* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * Modifications: Added PACKET_MMAP support
+ *
+ * based on previous works of:
+ *
+ * Monitor-mode support for mac80211 includes code taken from the iw
+ * command; the copyright notice for that code is
+ *
+ * Copyright (c) 2007, 2008 Johannes Berg
+ * Copyright (c) 2007 Andy Lutomirski
+ * Copyright (c) 2007 Mike Kershaw
+ * Copyright (c) 2008 Gábor Stefanik
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
*/
#ifndef lint
-static const char rcsid[] =
- "@(#) $Header: /tcpdump/master/libpcap/pcap-linux.c,v 1.95 2003-07-25 05:32:04 guy Exp $ (LBL)";
+static const char rcsid[] _U_ =
+ "@(#) $Header: /tcpdump/master/libpcap/pcap-linux.c,v 1.164 2008-12-14 22:00:57 guy Exp $ (LBL)";
#endif
/*
*/
+#define _GNU_SOURCE
+
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
-#include "pcap-int.h"
-#include "sll.h"
-
-#ifdef HAVE_DAG_API
-#include "pcap-dag.h"
-#endif /* HAVE_DAG_API */
-
#include <errno.h>
+#include <stdio.h>
#include <stdlib.h>
+#include <ctype.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
+#include <limits.h>
+#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/utsname.h>
-#include <net/if.h>
+#include <sys/mman.h>
+#include <linux/if.h>
+#include <linux/if_packet.h>
#include <netinet/in.h>
#include <linux/if_ether.h>
#include <net/if_arp.h>
+#include <poll.h>
+#include <dirent.h>
+
+#include "pcap-int.h"
+#include "pcap/sll.h"
+#include "pcap/vlan.h"
+
+#ifdef HAVE_DAG_API
+#include "pcap-dag.h"
+#endif /* HAVE_DAG_API */
+
+#ifdef HAVE_SEPTEL_API
+#include "pcap-septel.h"
+#endif /* HAVE_SEPTEL_API */
+
+#ifdef HAVE_SNF_API
+#include "pcap-snf.h"
+#endif /* HAVE_SNF_API */
+
+#ifdef PCAP_SUPPORT_USB
+#include "pcap-usb-linux.h"
+#endif
+
+#ifdef PCAP_SUPPORT_BT
+#include "pcap-bt-linux.h"
+#endif
+
+#ifdef PCAP_SUPPORT_CAN
+#include "pcap-can-linux.h"
+#endif
+
+#if PCAP_SUPPORT_CANUSB
+#include "pcap-canusb-linux.h"
+#endif
+
+#ifdef PCAP_SUPPORT_NETFILTER
+#include "pcap-netfilter-linux.h"
+#endif
/*
* If PF_PACKET is defined, we can use {SOCK_RAW,SOCK_DGRAM}/PF_PACKET
*/
# ifdef PACKET_HOST
# define HAVE_PF_PACKET_SOCKETS
+# ifdef PACKET_AUXDATA
+# define HAVE_PACKET_AUXDATA
+# endif /* PACKET_AUXDATA */
# endif /* PACKET_HOST */
+
+
+ /* check for memory mapped access avaibility. We assume every needed
+ * struct is defined if the macro TPACKET_HDRLEN is defined, because it
+ * uses many ring related structs and macros */
+# ifdef TPACKET_HDRLEN
+# define HAVE_PACKET_RING
+# ifdef TPACKET2_HDRLEN
+# define HAVE_TPACKET2
+# else
+# define TPACKET_V1 0
+# endif /* TPACKET2_HDRLEN */
+# endif /* TPACKET_HDRLEN */
#endif /* PF_PACKET */
#ifdef SO_ATTACH_FILTER
#include <linux/filter.h>
#endif
-#ifndef __GLIBC__
+/*
+ * We need linux/sockios.h if we have linux/net_tstamp.h (for time stamp
+ * specification) or linux/ethtool.h (for ethtool ioctls to get offloading
+ * information).
+ */
+#if defined(HAVE_LINUX_NET_TSTAMP_H) || defined(HAVE_LINUX_ETHTOOL_H)
+#include <linux/sockios.h>
+#endif
+
+#ifdef HAVE_LINUX_NET_TSTAMP_H
+#include <linux/net_tstamp.h>
+#endif
+
+/*
+ * Got Wireless Extensions?
+ */
+#ifdef HAVE_LINUX_WIRELESS_H
+#include <linux/wireless.h>
+#endif /* HAVE_LINUX_WIRELESS_H */
+
+/*
+ * Got libnl?
+ */
+#ifdef HAVE_LIBNL
+#include <linux/nl80211.h>
+
+#include <netlink/genl/genl.h>
+#include <netlink/genl/family.h>
+#include <netlink/genl/ctrl.h>
+#include <netlink/msg.h>
+#include <netlink/attr.h>
+#endif /* HAVE_LIBNL */
+
+/*
+ * Got ethtool support?
+ */
+#ifdef HAVE_LINUX_ETHTOOL_H
+#include <linux/ethtool.h>
+#endif
+
+#ifndef HAVE_SOCKLEN_T
typedef int socklen_t;
#endif
#define BIGGER_THAN_ALL_MTUS (64*1024)
/*
- * Prototypes for internal functions
+ * Prototypes for internal functions and methods.
*/
-static void map_arphrd_to_dlt(pcap_t *, int, int);
-static int live_open_old(pcap_t *, const char *, int, int, char *);
-static int live_open_new(pcap_t *, const char *, int, int, char *);
+static void map_arphrd_to_dlt(pcap_t *, int, int, const char *, int);
+#ifdef HAVE_PF_PACKET_SOCKETS
+static short int map_packet_type_to_sll_type(short int);
+#endif
+static int pcap_activate_linux(pcap_t *);
+static int activate_old(pcap_t *);
+static int activate_new(pcap_t *);
+static int activate_mmap(pcap_t *, int *);
+static int pcap_can_set_rfmon_linux(pcap_t *);
static int pcap_read_linux(pcap_t *, int, pcap_handler, u_char *);
static int pcap_read_packet(pcap_t *, pcap_handler, u_char *);
+static int pcap_inject_linux(pcap_t *, const void *, size_t);
static int pcap_stats_linux(pcap_t *, struct pcap_stat *);
static int pcap_setfilter_linux(pcap_t *, struct bpf_program *);
-static void pcap_close_linux(pcap_t *);
+static int pcap_setdirection_linux(pcap_t *, pcap_direction_t);
+static void pcap_cleanup_linux(pcap_t *);
+
+union thdr {
+ struct tpacket_hdr *h1;
+ struct tpacket2_hdr *h2;
+ void *raw;
+};
+
+#ifdef HAVE_PACKET_RING
+#define RING_GET_FRAME(h) (((union thdr **)h->buffer)[h->offset])
+
+static void destroy_ring(pcap_t *handle);
+static int create_ring(pcap_t *handle, int *status);
+static int prepare_tpacket_socket(pcap_t *handle);
+static void pcap_cleanup_linux_mmap(pcap_t *);
+static int pcap_read_linux_mmap(pcap_t *, int, pcap_handler , u_char *);
+static int pcap_setfilter_linux_mmap(pcap_t *, struct bpf_program *);
+static int pcap_setnonblock_mmap(pcap_t *p, int nonblock, char *errbuf);
+static int pcap_getnonblock_mmap(pcap_t *p, char *errbuf);
+static void pcap_oneshot_mmap(u_char *user, const struct pcap_pkthdr *h,
+ const u_char *bytes);
+#endif
/*
* Wrap some ioctl calls
*/
#ifdef HAVE_PF_PACKET_SOCKETS
static int iface_get_id(int fd, const char *device, char *ebuf);
-#endif
+#endif /* HAVE_PF_PACKET_SOCKETS */
static int iface_get_mtu(int fd, const char *device, char *ebuf);
static int iface_get_arptype(int fd, const char *device, char *ebuf);
#ifdef HAVE_PF_PACKET_SOCKETS
static int iface_bind(int fd, int ifindex, char *ebuf);
-#endif
+#ifdef IW_MODE_MONITOR
+static int has_wext(int sock_fd, const char *device, char *ebuf);
+#endif /* IW_MODE_MONITOR */
+static int enter_rfmon_mode(pcap_t *handle, int sock_fd,
+ const char *device);
+#endif /* HAVE_PF_PACKET_SOCKETS */
+static int iface_get_offload(pcap_t *handle);
static int iface_bind_old(int fd, const char *device, char *ebuf);
#ifdef SO_ATTACH_FILTER
-static int fix_program(pcap_t *handle, struct sock_fprog *fcode);
+static int fix_program(pcap_t *handle, struct sock_fprog *fcode,
+ int is_mapped);
static int fix_offset(struct bpf_insn *p);
static int set_kernel_filter(pcap_t *handle, struct sock_fprog *fcode);
static int reset_kernel_filter(pcap_t *handle);
= BPF_STMT(BPF_RET | BPF_K, 0);
static struct sock_fprog total_fcode
= { 1, &total_insn };
-#endif
+#endif /* SO_ATTACH_FILTER */
-/*
- * Get a handle for a live capture from the given device. You can
- * pass NULL as device to get all packages (without link level
- * information of course). If you pass 1 as promisc the interface
- * will be set to promiscous mode (XXX: I think this usage should
- * be deprecated and functions be added to select that later allow
- * modification of that values -- Torsten).
- *
- * See also pcap(3).
- */
pcap_t *
-pcap_open_live(const char *device, int snaplen, int promisc, int to_ms,
- char *ebuf)
+pcap_create(const char *device, char *ebuf)
{
- pcap_t *handle;
- int mtu;
- int err;
- int live_open_ok = 0;
- struct utsname utsname;
+ pcap_t *handle;
+
+ /*
+ * A null device name is equivalent to the "any" device.
+ */
+ if (device == NULL)
+ device = "any";
#ifdef HAVE_DAG_API
if (strstr(device, "dag")) {
- return dag_open_live(device, snaplen, promisc, to_ms, ebuf);
+ return dag_create(device, ebuf);
}
#endif /* HAVE_DAG_API */
- /* Allocate a handle for this session. */
-
- handle = malloc(sizeof(*handle));
- if (handle == NULL) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
- pcap_strerror(errno));
- return NULL;
+#ifdef HAVE_SEPTEL_API
+ if (strstr(device, "septel")) {
+ return septel_create(device, ebuf);
}
+#endif /* HAVE_SEPTEL_API */
- /* Initialize some components of the pcap structure. */
+#ifdef HAVE_SNF_API
+ handle = snf_create(device, ebuf);
+ if (strstr(device, "snf") || handle != NULL)
+ return handle;
- memset(handle, 0, sizeof(*handle));
- handle->snapshot = snaplen;
- handle->md.timeout = to_ms;
+#endif /* HAVE_SNF_API */
- /*
- * NULL and "any" are special devices which give us the hint to
- * monitor all devices.
- */
- if (!device || strcmp(device, "any") == 0) {
- device = NULL;
- handle->md.device = strdup("any");
- if (promisc) {
- promisc = 0;
- /* Just a warning. */
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "Promiscuous mode not supported on the \"any\" device");
- }
+#ifdef PCAP_SUPPORT_BT
+ if (strstr(device, "bluetooth")) {
+ return bt_create(device, ebuf);
+ }
+#endif
- } else
- handle->md.device = strdup(device);
+#if PCAP_SUPPORT_CANUSB
+ if (strstr(device, "canusb")) {
+ return canusb_create(device, ebuf);
+ }
+#endif
- if (handle->md.device == NULL) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE, "strdup: %s",
- pcap_strerror(errno) );
- free(handle);
- return NULL;
+#ifdef PCAP_SUPPORT_CAN
+ if ((strncmp(device, "can", 3) == 0 && isdigit(device[3])) ||
+ (strncmp(device, "vcan", 4) == 0 && isdigit(device[4]))) {
+ return can_create(device, ebuf);
}
+#endif
- /*
- * Current Linux kernels use the protocol family PF_PACKET to
- * allow direct access to all packets on the network while
- * older kernels had a special socket type SOCK_PACKET to
- * implement this feature.
- * While this old implementation is kind of obsolete we need
- * to be compatible with older kernels for a while so we are
- * trying both methods with the newer method preferred.
- */
+#ifdef PCAP_SUPPORT_USB
+ if (strstr(device, "usbmon")) {
+ return usb_create(device, ebuf);
+ }
+#endif
- if ((err = live_open_new(handle, device, promisc, to_ms, ebuf)) == 1)
- live_open_ok = 1;
- else if (err == 0) {
- /* Non-fatal error; try old way */
- if (live_open_old(handle, device, promisc, to_ms, ebuf))
- live_open_ok = 1;
+#ifdef PCAP_SUPPORT_NETFILTER
+ if (strncmp(device, "nflog", strlen("nflog")) == 0) {
+ return nflog_create(device, ebuf);
}
- if (!live_open_ok) {
- /*
- * Both methods to open the packet socket failed. Tidy
- * up and report our failure (ebuf is expected to be
- * set by the functions above).
- */
+#endif
- if (handle->md.device != NULL)
- free(handle->md.device);
- free(handle);
+ handle = pcap_create_common(device, ebuf);
+ if (handle == NULL)
return NULL;
- }
+ handle->activate_op = pcap_activate_linux;
+ handle->can_set_rfmon_op = pcap_can_set_rfmon_linux;
+#if defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP)
/*
- * Compute the buffer size.
+ * We claim that we support:
+ *
+ * software time stamps, with no details about their precision;
+ * hardware time stamps, synced to the host time;
+ * hardware time stamps, not synced to the host time.
*
- * If we're using SOCK_PACKET, this might be a 2.0[.x] kernel,
- * and might require special handling - check.
+ * XXX - we can't ask a device whether it supports
+ * hardware time stamps, so we just claim all devices do.
*/
- if (handle->md.sock_packet && (uname(&utsname) < 0 ||
- strncmp(utsname.release, "2.0", 3) == 0)) {
- /*
- * We're using a SOCK_PACKET structure, and either
- * we couldn't find out what kernel release this is,
- * or it's a 2.0[.x] kernel.
- *
- * In the 2.0[.x] kernel, a "recvfrom()" on
- * a SOCK_PACKET socket, with MSG_TRUNC set, will
- * return the number of bytes read, so if we pass
- * a length based on the snapshot length, it'll
- * return the number of bytes from the packet
- * copied to userland, not the actual length
- * of the packet.
- *
- * This means that, for example, the IP dissector
- * in tcpdump will get handed a packet length less
- * than the length in the IP header, and will
- * complain about "truncated-ip".
- *
- * So we don't bother trying to copy from the
- * kernel only the bytes in which we're interested,
- * but instead copy them all, just as the older
- * versions of libpcap for Linux did.
- *
- * The buffer therefore needs to be big enough to
- * hold the largest packet we can get from this
- * device. Unfortunately, we can't get the MRU
- * of the network; we can only get the MTU. The
- * MTU may be too small, in which case a packet larger
- * than the buffer size will be truncated *and* we
- * won't get the actual packet size.
- *
- * However, if the snapshot length is larger than
- * the buffer size based on the MTU, we use the
- * snapshot length as the buffer size, instead;
- * this means that with a sufficiently large snapshot
- * length we won't artificially truncate packets
- * to the MTU-based size.
- *
- * This mess just one of many problems with packet
- * capture on 2.0[.x] kernels; you really want a
- * 2.2[.x] or later kernel if you want packet capture
- * to work well.
- */
- mtu = iface_get_mtu(handle->fd, device, ebuf);
- if (mtu == -1) {
- pcap_close_linux(handle);
- free(handle);
- return NULL;
- }
- handle->bufsize = MAX_LINKHEADER_SIZE + mtu;
- if (handle->bufsize < handle->snapshot)
- handle->bufsize = handle->snapshot;
- } else {
- /*
- * This is a 2.2[.x] or later kernel (we know that
- * either because we're not using a SOCK_PACKET
- * socket - PF_PACKET is supported only in 2.2
- * and later kernels - or because we checked the
- * kernel version).
- *
- * We can safely pass "recvfrom()" a byte count
- * based on the snapshot length.
- */
- handle->bufsize = handle->snapshot;
- }
-
- /* Allocate the buffer */
-
- handle->buffer = malloc(handle->bufsize + handle->offset);
- if (!handle->buffer) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "malloc: %s", pcap_strerror(errno));
- pcap_close_linux(handle);
+ handle->tstamp_type_count = 3;
+ handle->tstamp_type_list = malloc(3 * sizeof(u_int));
+ if (handle->tstamp_type_list == NULL) {
free(handle);
return NULL;
}
-
- handle->read_op = pcap_read_linux;
- handle->setfilter_op = pcap_setfilter_linux;
- handle->set_datalink_op = NULL; /* can't change data link type */
- handle->stats_op = pcap_stats_linux;
- handle->close_op = pcap_close_linux;
+ handle->tstamp_type_list[0] = PCAP_TSTAMP_HOST;
+ handle->tstamp_type_list[1] = PCAP_TSTAMP_ADAPTER;
+ handle->tstamp_type_list[2] = PCAP_TSTAMP_ADAPTER_UNSYNCED;
+#endif
return handle;
}
+#ifdef HAVE_LIBNL
/*
- * Read at most max_packets from the capture stream and call the callback
- * for each of them. Returns the number of packets handled or -1 if an
- * error occured.
- */
-static int
-pcap_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
-{
- /*
- * Currently, on Linux only one packet is delivered per read,
- * so we don't loop.
- */
- return pcap_read_packet(handle, callback, user);
-}
+ * If interface {if} is a mac80211 driver, the file
+ * /sys/class/net/{if}/phy80211 is a symlink to
+ * /sys/class/ieee80211/{phydev}, for some {phydev}.
+ *
+ * On Fedora 9, with a 2.6.26.3-29 kernel, my Zydas stick, at
+ * least, has a "wmaster0" device and a "wlan0" device; the
+ * latter is the one with the IP address. Both show up in
+ * "tcpdump -D" output. Capturing on the wmaster0 device
+ * captures with 802.11 headers.
+ *
+ * airmon-ng searches through /sys/class/net for devices named
+ * monN, starting with mon0; as soon as one *doesn't* exist,
+ * it chooses that as the monitor device name. If the "iw"
+ * command exists, it does "iw dev {if} interface add {monif}
+ * type monitor", where {monif} is the monitor device. It
+ * then (sigh) sleeps .1 second, and then configures the
+ * device up. Otherwise, if /sys/class/ieee80211/{phydev}/add_iface
+ * is a file, it writes {mondev}, without a newline, to that file,
+ * and again (sigh) sleeps .1 second, and then iwconfig's that
+ * device into monitor mode and configures it up. Otherwise,
+ * you can't do monitor mode.
+ *
+ * All these devices are "glued" together by having the
+ * /sys/class/net/{device}/phy80211 links pointing to the same
+ * place, so, given a wmaster, wlan, or mon device, you can
+ * find the other devices by looking for devices with
+ * the same phy80211 link.
+ *
+ * To turn monitor mode off, delete the monitor interface,
+ * either with "iw dev {monif} interface del" or by sending
+ * {monif}, with no NL, down /sys/class/ieee80211/{phydev}/remove_iface
+ *
+ * Note: if you try to create a monitor device named "monN", and
+ * there's already a "monN" device, it fails, as least with
+ * the netlink interface (which is what iw uses), with a return
+ * value of -ENFILE. (Return values are negative errnos.) We
+ * could probably use that to find an unused device.
+ *
+ * Yes, you can have multiple monitor devices for a given
+ * physical device.
+*/
/*
- * Read a packet from the socket calling the handler provided by
- * the user. Returns the number of packets received or -1 if an
- * error occured.
+ * Is this a mac80211 device? If so, fill in the physical device path and
+ * return 1; if not, return 0. On an error, fill in handle->errbuf and
+ * return PCAP_ERROR.
*/
static int
-pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata)
+get_mac80211_phydev(pcap_t *handle, const char *device, char *phydev_path,
+ size_t phydev_max_pathlen)
{
- u_char *bp;
- int offset;
-#ifdef HAVE_PF_PACKET_SOCKETS
- struct sockaddr_ll from;
- struct sll_header *hdrp;
-#else
- struct sockaddr from;
-#endif
- socklen_t fromlen;
- int packet_len, caplen;
- struct pcap_pkthdr pcap_header;
+ char *pathstr;
+ ssize_t bytes_read;
-#ifdef HAVE_PF_PACKET_SOCKETS
/*
- * If this is a cooked device, leave extra room for a
- * fake packet header.
- */
- if (handle->md.cooked)
- offset = SLL_HDR_LEN;
- else
- offset = 0;
-#else
- /*
- * This system doesn't have PF_PACKET sockets, so it doesn't
- * support cooked devices.
+ * Generate the path string for the symlink to the physical device.
*/
- offset = 0;
-#endif
+ if (asprintf(&pathstr, "/sys/class/net/%s/phy80211", device) == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: Can't generate path name string for /sys/class/net device",
+ device);
+ return PCAP_ERROR;
+ }
+ bytes_read = readlink(pathstr, phydev_path, phydev_max_pathlen);
+ if (bytes_read == -1) {
+ if (errno == ENOENT || errno == EINVAL) {
+ /*
+ * Doesn't exist, or not a symlink; assume that
+ * means it's not a mac80211 device.
+ */
+ free(pathstr);
+ return 0;
+ }
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: Can't readlink %s: %s", device, pathstr,
+ strerror(errno));
+ free(pathstr);
+ return PCAP_ERROR;
+ }
+ free(pathstr);
+ phydev_path[bytes_read] = '\0';
+ return 1;
+}
- /* Receive a single packet from the kernel */
+#ifdef HAVE_LIBNL_2_x
+#define get_nl_errmsg nl_geterror
+#else
+/* libnl 2.x compatibility code */
- bp = handle->buffer + handle->offset;
- do {
- fromlen = sizeof(from);
- packet_len = recvfrom(
- handle->fd, bp + offset,
- handle->bufsize - offset, MSG_TRUNC,
- (struct sockaddr *) &from, &fromlen);
- } while (packet_len == -1 && errno == EINTR);
+#define nl_sock nl_handle
- /* Check if an error occured */
+static inline struct nl_handle *
+nl_socket_alloc(void)
+{
+ return nl_handle_alloc();
+}
- if (packet_len == -1) {
- if (errno == EAGAIN)
- return 0; /* no packet there */
- else {
- snprintf(handle->errbuf, sizeof(handle->errbuf),
- "recvfrom: %s", pcap_strerror(errno));
- return -1;
- }
- }
+static inline void
+nl_socket_free(struct nl_handle *h)
+{
+ nl_handle_destroy(h);
+}
-#ifdef HAVE_PF_PACKET_SOCKETS
- /*
- * If this is from the loopback device, reject outgoing packets;
- * we'll see the packet as an incoming packet as well, and
- * we don't want to see it twice.
- *
- * We can only do this if we're using PF_PACKET; the address
- * returned for SOCK_PACKET is a "sockaddr_pkt" which lacks
- * the relevant packet type information.
- */
- if (!handle->md.sock_packet &&
- from.sll_ifindex == handle->md.lo_ifindex &&
- from.sll_pkttype == PACKET_OUTGOING)
- return 0;
-#endif
+#define get_nl_errmsg strerror
-#ifdef HAVE_PF_PACKET_SOCKETS
- /*
- * If this is a cooked device, fill in the fake packet header.
- */
- if (handle->md.cooked) {
- /*
- * Add the length of the fake header to the length
- * of packet data we read.
- */
- packet_len += SLL_HDR_LEN;
+static inline int
+__genl_ctrl_alloc_cache(struct nl_handle *h, struct nl_cache **cache)
+{
+ struct nl_cache *tmp = genl_ctrl_alloc_cache(h);
+ if (!tmp)
+ return -ENOMEM;
+ *cache = tmp;
+ return 0;
+}
+#define genl_ctrl_alloc_cache __genl_ctrl_alloc_cache
+#endif /* !HAVE_LIBNL_2_x */
- hdrp = (struct sll_header *)bp;
+struct nl80211_state {
+ struct nl_sock *nl_sock;
+ struct nl_cache *nl_cache;
+ struct genl_family *nl80211;
+};
- /*
- * Map the PACKET_ value to a LINUX_SLL_ value; we
- * want the same numerical value to be used in
- * the link-layer header even if the numerical values
- * for the PACKET_ #defines change, so that programs
- * that look at the packet type field will always be
- * able to handle DLT_LINUX_SLL captures.
- */
- switch (from.sll_pkttype) {
+static int
+nl80211_init(pcap_t *handle, struct nl80211_state *state, const char *device)
+{
+ int err;
- case PACKET_HOST:
- hdrp->sll_pkttype = htons(LINUX_SLL_HOST);
- break;
+ state->nl_sock = nl_socket_alloc();
+ if (!state->nl_sock) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: failed to allocate netlink handle", device);
+ return PCAP_ERROR;
+ }
- case PACKET_BROADCAST:
- hdrp->sll_pkttype = htons(LINUX_SLL_BROADCAST);
- break;
+ if (genl_connect(state->nl_sock)) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: failed to connect to generic netlink", device);
+ goto out_handle_destroy;
+ }
- case PACKET_MULTICAST:
- hdrp->sll_pkttype = htons(LINUX_SLL_MULTICAST);
- break;
+ err = genl_ctrl_alloc_cache(state->nl_sock, &state->nl_cache);
+ if (err < 0) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: failed to allocate generic netlink cache: %s",
+ device, get_nl_errmsg(-err));
+ goto out_handle_destroy;
+ }
- case PACKET_OTHERHOST:
- hdrp->sll_pkttype = htons(LINUX_SLL_OTHERHOST);
- break;
+ state->nl80211 = genl_ctrl_search_by_name(state->nl_cache, "nl80211");
+ if (!state->nl80211) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: nl80211 not found", device);
+ goto out_cache_free;
+ }
- case PACKET_OUTGOING:
- hdrp->sll_pkttype = htons(LINUX_SLL_OUTGOING);
- break;
+ return 0;
- default:
- hdrp->sll_pkttype = -1;
- break;
- }
+out_cache_free:
+ nl_cache_free(state->nl_cache);
+out_handle_destroy:
+ nl_socket_free(state->nl_sock);
+ return PCAP_ERROR;
+}
- hdrp->sll_hatype = htons(from.sll_hatype);
- hdrp->sll_halen = htons(from.sll_halen);
- memcpy(hdrp->sll_addr, from.sll_addr,
- (from.sll_halen > SLL_ADDRLEN) ?
- SLL_ADDRLEN :
- from.sll_halen);
- hdrp->sll_protocol = from.sll_protocol;
+static void
+nl80211_cleanup(struct nl80211_state *state)
+{
+ genl_family_put(state->nl80211);
+ nl_cache_free(state->nl_cache);
+ nl_socket_free(state->nl_sock);
+}
+
+static int
+add_mon_if(pcap_t *handle, int sock_fd, struct nl80211_state *state,
+ const char *device, const char *mondevice)
+{
+ int ifindex;
+ struct nl_msg *msg;
+ int err;
+
+ ifindex = iface_get_id(sock_fd, device, handle->errbuf);
+ if (ifindex == -1)
+ return PCAP_ERROR;
+
+ msg = nlmsg_alloc();
+ if (!msg) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: failed to allocate netlink msg", device);
+ return PCAP_ERROR;
+ }
+
+ genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0,
+ 0, NL80211_CMD_NEW_INTERFACE, 0);
+ NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex);
+ NLA_PUT_STRING(msg, NL80211_ATTR_IFNAME, mondevice);
+ NLA_PUT_U32(msg, NL80211_ATTR_IFTYPE, NL80211_IFTYPE_MONITOR);
+
+ err = nl_send_auto_complete(state->nl_sock, msg);
+ if (err < 0) {
+#ifdef HAVE_LIBNL_2_x
+ if (err == -NLE_FAILURE) {
+#else
+ if (err == -ENFILE) {
+#endif
+ /*
+ * Device not available; our caller should just
+ * keep trying. (libnl 2.x maps ENFILE to
+ * NLE_FAILURE; it can also map other errors
+ * to that, but there's not much we can do
+ * about that.)
+ */
+ nlmsg_free(msg);
+ return 0;
+ } else {
+ /*
+ * Real failure, not just "that device is not
+ * available.
+ */
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: nl_send_auto_complete failed adding %s interface: %s",
+ device, mondevice, get_nl_errmsg(-err));
+ nlmsg_free(msg);
+ return PCAP_ERROR;
+ }
}
+ err = nl_wait_for_ack(state->nl_sock);
+ if (err < 0) {
+#ifdef HAVE_LIBNL_2_x
+ if (err == -NLE_FAILURE) {
+#else
+ if (err == -ENFILE) {
#endif
+ /*
+ * Device not available; our caller should just
+ * keep trying. (libnl 2.x maps ENFILE to
+ * NLE_FAILURE; it can also map other errors
+ * to that, but there's not much we can do
+ * about that.)
+ */
+ nlmsg_free(msg);
+ return 0;
+ } else {
+ /*
+ * Real failure, not just "that device is not
+ * available.
+ */
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: nl_wait_for_ack failed adding %s interface: %s",
+ device, mondevice, get_nl_errmsg(-err));
+ nlmsg_free(msg);
+ return PCAP_ERROR;
+ }
+ }
/*
- * XXX: According to the kernel source we should get the real
- * packet len if calling recvfrom with MSG_TRUNC set. It does
- * not seem to work here :(, but it is supported by this code
- * anyway.
- * To be honest the code RELIES on that feature so this is really
- * broken with 2.2.x kernels.
- * I spend a day to figure out what's going on and I found out
- * that the following is happening:
- *
- * The packet comes from a random interface and the packet_rcv
- * hook is called with a clone of the packet. That code inserts
- * the packet into the receive queue of the packet socket.
- * If a filter is attached to that socket that filter is run
- * first - and there lies the problem. The default filter always
- * cuts the packet at the snaplen:
- *
- * # tcpdump -d
- * (000) ret #68
- *
- * So the packet filter cuts down the packet. The recvfrom call
- * says "hey, it's only 68 bytes, it fits into the buffer" with
- * the result that we don't get the real packet length. This
- * is valid at least until kernel 2.2.17pre6.
- *
- * We currently handle this by making a copy of the filter
- * program, fixing all "ret" instructions with non-zero
- * operands to have an operand of 65535 so that the filter
- * doesn't truncate the packet, and supplying that modified
- * filter to the kernel.
+ * Success.
*/
+ nlmsg_free(msg);
+ return 1;
- caplen = packet_len;
- if (caplen > handle->snapshot)
- caplen = handle->snapshot;
+nla_put_failure:
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: nl_put failed adding %s interface",
+ device, mondevice);
+ nlmsg_free(msg);
+ return PCAP_ERROR;
+}
- /* Run the packet filter if not using kernel filter */
- if (!handle->md.use_bpf && handle->fcode.bf_insns) {
- if (bpf_filter(handle->fcode.bf_insns, bp,
- packet_len, caplen) == 0)
- {
- /* rejected by filter */
- return 0;
- }
+static int
+del_mon_if(pcap_t *handle, int sock_fd, struct nl80211_state *state,
+ const char *device, const char *mondevice)
+{
+ int ifindex;
+ struct nl_msg *msg;
+ int err;
+
+ ifindex = iface_get_id(sock_fd, mondevice, handle->errbuf);
+ if (ifindex == -1)
+ return PCAP_ERROR;
+
+ msg = nlmsg_alloc();
+ if (!msg) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: failed to allocate netlink msg", device);
+ return PCAP_ERROR;
}
- /* Fill in our own header data */
-
- if (ioctl(handle->fd, SIOCGSTAMP, &pcap_header.ts) == -1) {
- snprintf(handle->errbuf, sizeof(handle->errbuf),
- "ioctl: %s", pcap_strerror(errno));
- return -1;
+ genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0,
+ 0, NL80211_CMD_DEL_INTERFACE, 0);
+ NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex);
+
+ err = nl_send_auto_complete(state->nl_sock, msg);
+ if (err < 0) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: nl_send_auto_complete failed deleting %s interface: %s",
+ device, mondevice, get_nl_errmsg(-err));
+ nlmsg_free(msg);
+ return PCAP_ERROR;
+ }
+ err = nl_wait_for_ack(state->nl_sock);
+ if (err < 0) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: nl_wait_for_ack failed adding %s interface: %s",
+ device, mondevice, get_nl_errmsg(-err));
+ nlmsg_free(msg);
+ return PCAP_ERROR;
}
- pcap_header.caplen = caplen;
- pcap_header.len = packet_len;
/*
- * Count the packet.
- *
- * Arguably, we should count them before we check the filter,
- * as on many other platforms "ps_recv" counts packets
- * handed to the filter rather than packets that passed
- * the filter, but if filtering is done in the kernel, we
- * can't get a count of packets that passed the filter,
- * and that would mean the meaning of "ps_recv" wouldn't
- * be the same on all Linux systems.
- *
- * XXX - it's not the same on all systems in any case;
- * ideally, we should have a "get the statistics" call
- * that supplies more counts and indicates which of them
- * it supplies, so that we supply a count of packets
- * handed to the filter only on platforms where that
- * information is available.
- *
- * We count them here even if we can get the packet count
- * from the kernel, as we can only determine at run time
- * whether we'll be able to get it from the kernel (if
- * HAVE_TPACKET_STATS isn't defined, we can't get it from
- * the kernel, but if it is defined, the library might
- * have been built with a 2.4 or later kernel, but we
- * might be running on a 2.2[.x] kernel without Alexey
- * Kuznetzov's turbopacket patches, and thus the kernel
- * might not be able to supply those statistics). We
- * could, I guess, try, when opening the socket, to get
- * the statistics, and if we can not increment the count
- * here, but it's not clear that always incrementing
- * the count is more expensive than always testing a flag
- * in memory.
+ * Success.
*/
- handle->md.stat.ps_recv++;
-
- /* Call the user supplied callback function */
- callback(userdata, &pcap_header, bp);
-
+ nlmsg_free(msg);
return 1;
+
+nla_put_failure:
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: nl_put failed deleting %s interface",
+ device, mondevice);
+ nlmsg_free(msg);
+ return PCAP_ERROR;
}
-/*
- * Get the statistics for the given packet capture handle.
- * Reports the number of dropped packets iff the kernel supports
- * the PACKET_STATISTICS "getsockopt()" argument (2.4 and later
- * kernels, and 2.2[.x] kernels with Alexey Kuznetzov's turbopacket
- * patches); otherwise, that information isn't available, and we lie
- * and report 0 as the count of dropped packets.
- */
static int
-pcap_stats_linux(pcap_t *handle, struct pcap_stat *stats)
+enter_rfmon_mode_mac80211(pcap_t *handle, int sock_fd, const char *device)
{
-#ifdef HAVE_TPACKET_STATS
- struct tpacket_stats kstats;
- socklen_t len = sizeof (struct tpacket_stats);
-#endif
+ int ret;
+ char phydev_path[PATH_MAX+1];
+ struct nl80211_state nlstate;
+ struct ifreq ifr;
+ u_int n;
-#ifdef HAVE_TPACKET_STATS
/*
- * Try to get the packet counts from the kernel.
+ * Is this a mac80211 device?
*/
- if (getsockopt(handle->fd, SOL_PACKET, PACKET_STATISTICS,
- &kstats, &len) > -1) {
- /*
- * In "linux/net/packet/af_packet.c", at least in the
- * 2.4.9 kernel, "tp_packets" is incremented for every
- * packet that passes the packet filter *and* is
- * successfully queued on the socket; "tp_drops" is
- * incremented for every packet dropped because there's
- * not enough free space in the socket buffer.
- *
- * When the statistics are returned for a PACKET_STATISTICS
- * "getsockopt()" call, "tp_drops" is added to "tp_packets",
- * so that "tp_packets" counts all packets handed to
- * the PF_PACKET socket, including packets dropped because
- * there wasn't room on the socket buffer - but not
- * including packets that didn't pass the filter.
- *
- * In the BSD BPF, the count of received packets is
- * incremented for every packet handed to BPF, regardless
- * of whether it passed the filter.
- *
- * We can't make "pcap_stats()" work the same on both
- * platforms, but the best approximation is to return
- * "tp_packets" as the count of packets and "tp_drops"
- * as the count of drops.
- */
- handle->md.stat.ps_recv = kstats.tp_packets;
- handle->md.stat.ps_drop = kstats.tp_drops;
- }
- else
- {
+ ret = get_mac80211_phydev(handle, device, phydev_path, PATH_MAX);
+ if (ret < 0)
+ return ret; /* error */
+ if (ret == 0)
+ return 0; /* no error, but not mac80211 device */
+
+ /*
+ * XXX - is this already a monN device?
+ * If so, we're done.
+ * Is that determined by old Wireless Extensions ioctls?
+ */
+
+ /*
+ * OK, it's apparently a mac80211 device.
+ * Try to find an unused monN device for it.
+ */
+ ret = nl80211_init(handle, &nlstate, device);
+ if (ret != 0)
+ return ret;
+ for (n = 0; n < UINT_MAX; n++) {
/*
- * If the error was EOPNOTSUPP, fall through, so that
- * if you build the library on a system with
- * "struct tpacket_stats" and run it on a system
- * that doesn't, it works as it does if the library
- * is built on a system without "struct tpacket_stats".
+ * Try mon{n}.
*/
- if (errno != EOPNOTSUPP) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "pcap_stats: %s", pcap_strerror(errno));
- return -1;
+ char mondevice[3+10+1]; /* mon{UINT_MAX}\0 */
+
+ snprintf(mondevice, sizeof mondevice, "mon%u", n);
+ ret = add_mon_if(handle, sock_fd, &nlstate, device, mondevice);
+ if (ret == 1) {
+ handle->md.mondevice = strdup(mondevice);
+ goto added;
+ }
+ if (ret < 0) {
+ /*
+ * Hard failure. Just return ret; handle->errbuf
+ * has already been set.
+ */
+ nl80211_cleanup(&nlstate);
+ return ret;
}
}
+
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: No free monN interfaces", device);
+ nl80211_cleanup(&nlstate);
+ return PCAP_ERROR;
+
+added:
+
+#if 0
+ /*
+ * Sleep for .1 seconds.
+ */
+ delay.tv_sec = 0;
+ delay.tv_nsec = 500000000;
+ nanosleep(&delay, NULL);
#endif
+
/*
- * On systems where the PACKET_STATISTICS "getsockopt()" argument
- * is supported on PF_PACKET sockets:
- *
- * "ps_recv" counts only packets that *passed* the filter,
- * not packets that didn't pass the filter. This includes
- * packets later dropped because we ran out of buffer space.
- *
- * "ps_drop" counts packets dropped because we ran out of
- * buffer space. It doesn't count packets dropped by the
- * interface driver. It counts only packets that passed
- * the filter.
- *
- * Both statistics include packets not yet read from the
- * kernel by libpcap, and thus not yet seen by the application.
- *
- * On systems where the PACKET_STATISTICS "getsockopt()" argument
- * is not supported on PF_PACKET sockets:
- *
- * "ps_recv" counts only packets that *passed* the filter,
- * not packets that didn't pass the filter. It does not
- * count packets dropped because we ran out of buffer
- * space.
- *
- * "ps_drop" is not supported.
- *
- * "ps_recv" doesn't include packets not yet read from
- * the kernel by libpcap.
+ * If we haven't already done so, arrange to have
+ * "pcap_close_all()" called when we exit.
*/
- *stats = handle->md.stat;
- return 0;
-}
+ if (!pcap_do_addexit(handle)) {
+ /*
+ * "atexit()" failed; don't put the interface
+ * in rfmon mode, just give up.
+ */
+ return PCAP_ERROR_RFMON_NOTSUP;
+ }
-/*
- * Description string for the "any" device.
- */
-static const char any_descr[] = "Pseudo-device that captures on all interfaces";
+ /*
+ * Now configure the monitor interface up.
+ */
+ memset(&ifr, 0, sizeof(ifr));
+ strncpy(ifr.ifr_name, handle->md.mondevice, sizeof(ifr.ifr_name));
+ if (ioctl(sock_fd, SIOCGIFFLAGS, &ifr) == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: Can't get flags for %s: %s", device,
+ handle->md.mondevice, strerror(errno));
+ del_mon_if(handle, sock_fd, &nlstate, device,
+ handle->md.mondevice);
+ nl80211_cleanup(&nlstate);
+ return PCAP_ERROR;
+ }
+ ifr.ifr_flags |= IFF_UP|IFF_RUNNING;
+ if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: Can't set flags for %s: %s", device,
+ handle->md.mondevice, strerror(errno));
+ del_mon_if(handle, sock_fd, &nlstate, device,
+ handle->md.mondevice);
+ nl80211_cleanup(&nlstate);
+ return PCAP_ERROR;
+ }
-int
-pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
-{
- if (pcap_add_if(alldevsp, "any", 0, any_descr, errbuf) < 0)
- return (-1);
+ /*
+ * Success. Clean up the libnl state.
+ */
+ nl80211_cleanup(&nlstate);
-#ifdef HAVE_DAG_API
- if (dag_platform_finddevs(alldevsp, errbuf) < 0)
- return (-1);
-#endif /* HAVE_DAG_API */
+ /*
+ * Note that we have to delete the monitor device when we close
+ * the handle.
+ */
+ handle->md.must_do_on_close |= MUST_DELETE_MONIF;
- return (0);
+ /*
+ * Add this to the list of pcaps to close when we exit.
+ */
+ pcap_add_to_pcaps_to_close(handle);
+
+ return 1;
}
+#endif /* HAVE_LIBNL */
-/*
- * Attach the given BPF code to the packet capture device.
- */
static int
-pcap_setfilter_linux(pcap_t *handle, struct bpf_program *filter)
+pcap_can_set_rfmon_linux(pcap_t *handle)
{
-#ifdef SO_ATTACH_FILTER
- struct sock_fprog fcode;
- int can_filter_in_kernel;
- int err = 0;
+#ifdef HAVE_LIBNL
+ char phydev_path[PATH_MAX+1];
+ int ret;
+#endif
+#ifdef IW_MODE_MONITOR
+ int sock_fd;
+ struct iwreq ireq;
#endif
- if (!handle)
- return -1;
- if (!filter) {
- strncpy(handle->errbuf, "setfilter: No filter specified",
- sizeof(handle->errbuf));
- return -1;
+ if (strcmp(handle->opt.source, "any") == 0) {
+ /*
+ * Monitor mode makes no sense on the "any" device.
+ */
+ return 0;
}
- /* Make our private copy of the filter */
-
- if (install_bpf_program(handle, filter) < 0)
- /* install_bpf_program() filled in errbuf */
- return -1;
-
+#ifdef HAVE_LIBNL
/*
- * Run user level packet filter by default. Will be overriden if
- * installing a kernel filter succeeds.
+ * Bleah. There doesn't seem to be a way to ask a mac80211
+ * device, through libnl, whether it supports monitor mode;
+ * we'll just check whether the device appears to be a
+ * mac80211 device and, if so, assume the device supports
+ * monitor mode.
+ *
+ * wmaster devices don't appear to support the Wireless
+ * Extensions, but we can create a mon device for a
+ * wmaster device, so we don't bother checking whether
+ * a mac80211 device supports the Wireless Extensions.
*/
- handle->md.use_bpf = 0;
+ ret = get_mac80211_phydev(handle, handle->opt.source, phydev_path,
+ PATH_MAX);
+ if (ret < 0)
+ return ret; /* error */
+ if (ret == 1)
+ return 1; /* mac80211 device */
+#endif
- /* Install kernel level filter if possible */
+#ifdef IW_MODE_MONITOR
+ /*
+ * Bleah. There doesn't appear to be an ioctl to use to ask
+ * whether a device supports monitor mode; we'll just do
+ * SIOCGIWMODE and, if it succeeds, assume the device supports
+ * monitor mode.
+ *
+ * Open a socket on which to attempt to get the mode.
+ * (We assume that if we have Wireless Extensions support
+ * we also have PF_PACKET support.)
+ */
+ sock_fd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
+ if (sock_fd == -1) {
+ (void)snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "socket: %s", pcap_strerror(errno));
+ return PCAP_ERROR;
+ }
-#ifdef SO_ATTACH_FILTER
-#ifdef USHRT_MAX
- if (handle->fcode.bf_len > USHRT_MAX) {
+ /*
+ * Attempt to get the current mode.
+ */
+ strncpy(ireq.ifr_ifrn.ifrn_name, handle->opt.source,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ if (ioctl(sock_fd, SIOCGIWMODE, &ireq) != -1) {
/*
- * fcode.len is an unsigned short for current kernel.
- * I have yet to see BPF-Code with that much
- * instructions but still it is possible. So for the
- * sake of correctness I added this check.
+ * Well, we got the mode; assume we can set it.
*/
- fprintf(stderr, "Warning: Filter too complex for kernel\n");
- fcode.filter = NULL;
- can_filter_in_kernel = 0;
- } else
-#endif /* USHRT_MAX */
+ close(sock_fd);
+ return 1;
+ }
+ if (errno == ENODEV) {
+ /* The device doesn't even exist. */
+ (void)snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "SIOCGIWMODE failed: %s", pcap_strerror(errno));
+ close(sock_fd);
+ return PCAP_ERROR_NO_SUCH_DEVICE;
+ }
+ close(sock_fd);
+#endif
+ return 0;
+}
+
+/*
+ * Grabs the number of dropped packets by the interface from /proc/net/dev.
+ *
+ * XXX - what about /sys/class/net/{interface name}/rx_*? There are
+ * individual devices giving, in ASCII, various rx_ and tx_ statistics.
+ *
+ * Or can we get them in binary form from netlink?
+ */
+static long int
+linux_if_drops(const char * if_name)
+{
+ char buffer[512];
+ char * bufptr;
+ FILE * file;
+ int field_to_convert = 3, if_name_sz = strlen(if_name);
+ long int dropped_pkts = 0;
+
+ file = fopen("/proc/net/dev", "r");
+ if (!file)
+ return 0;
+
+ while (!dropped_pkts && fgets( buffer, sizeof(buffer), file ))
{
+ /* search for 'bytes' -- if its in there, then
+ that means we need to grab the fourth field. otherwise
+ grab the third field. */
+ if (field_to_convert != 4 && strstr(buffer, "bytes"))
+ {
+ field_to_convert = 4;
+ continue;
+ }
+
+ /* find iface and make sure it actually matches -- space before the name and : after it */
+ if ((bufptr = strstr(buffer, if_name)) &&
+ (bufptr == buffer || *(bufptr-1) == ' ') &&
+ *(bufptr + if_name_sz) == ':')
+ {
+ bufptr = bufptr + if_name_sz + 1;
+
+ /* grab the nth field from it */
+ while( --field_to_convert && *bufptr != '\0')
+ {
+ while (*bufptr != '\0' && *(bufptr++) == ' ');
+ while (*bufptr != '\0' && *(bufptr++) != ' ');
+ }
+
+ /* get rid of any final spaces */
+ while (*bufptr != '\0' && *bufptr == ' ') bufptr++;
+
+ if (*bufptr != '\0')
+ dropped_pkts = strtol(bufptr, NULL, 10);
+
+ break;
+ }
+ }
+
+ fclose(file);
+ return dropped_pkts;
+}
+
+
+/*
+ * With older kernels promiscuous mode is kind of interesting because we
+ * have to reset the interface before exiting. The problem can't really
+ * be solved without some daemon taking care of managing usage counts.
+ * If we put the interface into promiscuous mode, we set a flag indicating
+ * that we must take it out of that mode when the interface is closed,
+ * and, when closing the interface, if that flag is set we take it out
+ * of promiscuous mode.
+ *
+ * Even with newer kernels, we have the same issue with rfmon mode.
+ */
+
+static void pcap_cleanup_linux( pcap_t *handle )
+{
+ struct ifreq ifr;
+#ifdef HAVE_LIBNL
+ struct nl80211_state nlstate;
+ int ret;
+#endif /* HAVE_LIBNL */
+#ifdef IW_MODE_MONITOR
+ int oldflags;
+ struct iwreq ireq;
+#endif /* IW_MODE_MONITOR */
+
+ if (handle->md.must_do_on_close != 0) {
/*
- * Oh joy, the Linux kernel uses struct sock_fprog instead
- * of struct bpf_program and of course the length field is
- * of different size. Pointed out by Sebastian
- *
- * Oh, and we also need to fix it up so that all "ret"
- * instructions with non-zero operands have 65535 as the
- * operand, and so that, if we're in cooked mode, all
- * memory-reference instructions use special magic offsets
- * in references to the link-layer header and assume that
- * the link-layer payload begins at 0; "fix_program()"
- * will do that.
+ * There's something we have to do when closing this
+ * pcap_t.
*/
- switch (fix_program(handle, &fcode)) {
-
- case -1:
- default:
+ if (handle->md.must_do_on_close & MUST_CLEAR_PROMISC) {
/*
- * Fatal error; just quit.
- * (The "default" case shouldn't happen; we
- * return -1 for that reason.)
+ * We put the interface into promiscuous mode;
+ * take it out of promiscuous mode.
+ *
+ * XXX - if somebody else wants it in promiscuous
+ * mode, this code cannot know that, so it'll take
+ * it out of promiscuous mode. That's not fixable
+ * in 2.0[.x] kernels.
*/
- return -1;
+ memset(&ifr, 0, sizeof(ifr));
+ strncpy(ifr.ifr_name, handle->md.device,
+ sizeof(ifr.ifr_name));
+ if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) == -1) {
+ fprintf(stderr,
+ "Can't restore interface %s flags (SIOCGIFFLAGS failed: %s).\n"
+ "Please adjust manually.\n"
+ "Hint: This can't happen with Linux >= 2.2.0.\n",
+ handle->md.device, strerror(errno));
+ } else {
+ if (ifr.ifr_flags & IFF_PROMISC) {
+ /*
+ * Promiscuous mode is currently on;
+ * turn it off.
+ */
+ ifr.ifr_flags &= ~IFF_PROMISC;
+ if (ioctl(handle->fd, SIOCSIFFLAGS,
+ &ifr) == -1) {
+ fprintf(stderr,
+ "Can't restore interface %s flags (SIOCSIFFLAGS failed: %s).\n"
+ "Please adjust manually.\n"
+ "Hint: This can't happen with Linux >= 2.2.0.\n",
+ handle->md.device,
+ strerror(errno));
+ }
+ }
+ }
+ }
- case 0:
+#ifdef HAVE_LIBNL
+ if (handle->md.must_do_on_close & MUST_DELETE_MONIF) {
+ ret = nl80211_init(handle, &nlstate, handle->md.device);
+ if (ret >= 0) {
+ ret = del_mon_if(handle, handle->fd, &nlstate,
+ handle->md.device, handle->md.mondevice);
+ nl80211_cleanup(&nlstate);
+ }
+ if (ret < 0) {
+ fprintf(stderr,
+ "Can't delete monitor interface %s (%s).\n"
+ "Please delete manually.\n",
+ handle->md.mondevice, handle->errbuf);
+ }
+ }
+#endif /* HAVE_LIBNL */
+
+#ifdef IW_MODE_MONITOR
+ if (handle->md.must_do_on_close & MUST_CLEAR_RFMON) {
/*
- * The program performed checks that we can't make
- * work in the kernel.
+ * We put the interface into rfmon mode;
+ * take it out of rfmon mode.
+ *
+ * XXX - if somebody else wants it in rfmon
+ * mode, this code cannot know that, so it'll take
+ * it out of rfmon mode.
*/
- can_filter_in_kernel = 0;
- break;
- case 1:
/*
- * We have a filter that'll work in the kernel.
+ * First, take the interface down if it's up;
+ * otherwise, we might get EBUSY.
+ * If we get errors, just drive on and print
+ * a warning if we can't restore the mode.
*/
- can_filter_in_kernel = 1;
- break;
- }
- }
+ oldflags = 0;
+ memset(&ifr, 0, sizeof(ifr));
+ strncpy(ifr.ifr_name, handle->md.device,
+ sizeof(ifr.ifr_name));
+ if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) != -1) {
+ if (ifr.ifr_flags & IFF_UP) {
+ oldflags = ifr.ifr_flags;
+ ifr.ifr_flags &= ~IFF_UP;
+ if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1)
+ oldflags = 0; /* didn't set, don't restore */
+ }
+ }
- if (can_filter_in_kernel) {
- if ((err = set_kernel_filter(handle, &fcode)) == 0)
- {
- /* Installation succeded - using kernel filter. */
- handle->md.use_bpf = 1;
- }
- else if (err == -1) /* Non-fatal error */
- {
/*
- * Print a warning if we weren't able to install
- * the filter for a reason other than "this kernel
- * isn't configured to support socket filters.
+ * Now restore the mode.
*/
- if (errno != ENOPROTOOPT && errno != EOPNOTSUPP) {
+ strncpy(ireq.ifr_ifrn.ifrn_name, handle->md.device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1]
+ = 0;
+ ireq.u.mode = handle->md.oldmode;
+ if (ioctl(handle->fd, SIOCSIWMODE, &ireq) == -1) {
+ /*
+ * Scientist, you've failed.
+ */
fprintf(stderr,
- "Warning: Kernel filter failed: %s\n",
- pcap_strerror(errno));
+ "Can't restore interface %s wireless mode (SIOCSIWMODE failed: %s).\n"
+ "Please adjust manually.\n",
+ handle->md.device, strerror(errno));
}
- }
- }
-
- /*
- * If we're not using the kernel filter, get rid of any kernel
- * filter that might've been there before, e.g. because the
- * previous filter could work in the kernel, or because some other
- * code attached a filter to the socket by some means other than
- * calling "pcap_setfilter()". Otherwise, the kernel filter may
- * filter out packets that would pass the new userland filter.
- */
- if (!handle->md.use_bpf)
- reset_kernel_filter(handle);
- /*
- * Free up the copy of the filter that was made by "fix_program()".
- */
- if (fcode.filter != NULL)
- free(fcode.filter);
+ /*
+ * Now bring the interface back up if we brought
+ * it down.
+ */
+ if (oldflags != 0) {
+ ifr.ifr_flags = oldflags;
+ if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1) {
+ fprintf(stderr,
+ "Can't bring interface %s back up (SIOCSIFFLAGS failed: %s).\n"
+ "Please adjust manually.\n",
+ handle->md.device, strerror(errno));
+ }
+ }
+ }
+#endif /* IW_MODE_MONITOR */
- if (err == -2)
- /* Fatal error */
- return -1;
-#endif /* SO_ATTACH_FILTER */
+ /*
+ * Take this pcap out of the list of pcaps for which we
+ * have to take the interface out of some mode.
+ */
+ pcap_remove_from_pcaps_to_close(handle);
+ }
- return 0;
+ if (handle->md.mondevice != NULL) {
+ free(handle->md.mondevice);
+ handle->md.mondevice = NULL;
+ }
+ if (handle->md.device != NULL) {
+ free(handle->md.device);
+ handle->md.device = NULL;
+ }
+ pcap_cleanup_live_common(handle);
}
/*
- * Linux uses the ARP hardware type to identify the type of an
- * interface. pcap uses the DLT_xxx constants for this. This
- * function takes a pointer to a "pcap_t", and an ARPHRD_xxx
- * constant, as arguments, and sets "handle->linktype" to the
- * appropriate DLT_XXX constant and sets "handle->offset" to
- * the appropriate value (to make "handle->offset" plus link-layer
- * header length be a multiple of 4, so that the link-layer payload
- * will be aligned on a 4-byte boundary when capturing packets).
- * (If the offset isn't set here, it'll be 0; add code as appropriate
- * for cases where it shouldn't be 0.)
- *
- * If "cooked_ok" is non-zero, we can use DLT_LINUX_SLL and capture
- * in cooked mode; otherwise, we can't use cooked mode, so we have
- * to pick some type that works in raw mode, or fail.
- *
- * Sets the link type to -1 if unable to map the type.
+ * Get a handle for a live capture from the given device. You can
+ * pass NULL as device to get all packages (without link level
+ * information of course). If you pass 1 as promisc the interface
+ * will be set to promiscous mode (XXX: I think this usage should
+ * be deprecated and functions be added to select that later allow
+ * modification of that values -- Torsten).
*/
-static void map_arphrd_to_dlt(pcap_t *handle, int arptype, int cooked_ok)
+static int
+pcap_activate_linux(pcap_t *handle)
{
- switch (arptype) {
-
- case ARPHRD_ETHER:
- case ARPHRD_METRICOM:
- case ARPHRD_LOOPBACK:
- handle->linktype = DLT_EN10MB;
- handle->offset = 2;
- break;
+ const char *device;
+ int status = 0;
- case ARPHRD_EETHER:
- handle->linktype = DLT_EN3MB;
- break;
+ device = handle->opt.source;
- case ARPHRD_AX25:
- handle->linktype = DLT_AX25;
- break;
+ handle->inject_op = pcap_inject_linux;
+ handle->setfilter_op = pcap_setfilter_linux;
+ handle->setdirection_op = pcap_setdirection_linux;
+ handle->set_datalink_op = NULL; /* can't change data link type */
+ handle->getnonblock_op = pcap_getnonblock_fd;
+ handle->setnonblock_op = pcap_setnonblock_fd;
+ handle->cleanup_op = pcap_cleanup_linux;
+ handle->read_op = pcap_read_linux;
+ handle->stats_op = pcap_stats_linux;
- case ARPHRD_PRONET:
- handle->linktype = DLT_PRONET;
- break;
+ /*
+ * The "any" device is a special device which causes us not
+ * to bind to a particular device and thus to look at all
+ * devices.
+ */
+ if (strcmp(device, "any") == 0) {
+ if (handle->opt.promisc) {
+ handle->opt.promisc = 0;
+ /* Just a warning. */
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "Promiscuous mode not supported on the \"any\" device");
+ status = PCAP_WARNING_PROMISC_NOTSUP;
+ }
+ }
- case ARPHRD_CHAOS:
+ handle->md.device = strdup(device);
+ if (handle->md.device == NULL) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "strdup: %s",
+ pcap_strerror(errno) );
+ return PCAP_ERROR;
+ }
+
+ /*
+ * If we're in promiscuous mode, then we probably want
+ * to see when the interface drops packets too, so get an
+ * initial count from /proc/net/dev
+ */
+ if (handle->opt.promisc)
+ handle->md.proc_dropped = linux_if_drops(handle->md.device);
+
+ /*
+ * Current Linux kernels use the protocol family PF_PACKET to
+ * allow direct access to all packets on the network while
+ * older kernels had a special socket type SOCK_PACKET to
+ * implement this feature.
+ * While this old implementation is kind of obsolete we need
+ * to be compatible with older kernels for a while so we are
+ * trying both methods with the newer method preferred.
+ */
+ status = activate_new(handle);
+ if (status < 0) {
+ /*
+ * Fatal error with the new way; just fail.
+ * status has the error return; if it's PCAP_ERROR,
+ * handle->errbuf has been set appropriately.
+ */
+ goto fail;
+ }
+ if (status == 1) {
+ /*
+ * Success.
+ * Try to use memory-mapped access.
+ */
+ switch (activate_mmap(handle, &status)) {
+
+ case 1:
+ /*
+ * We succeeded. status has been
+ * set to the status to return,
+ * which might be 0, or might be
+ * a PCAP_WARNING_ value.
+ */
+ return status;
+
+ case 0:
+ /*
+ * Kernel doesn't support it - just continue
+ * with non-memory-mapped access.
+ */
+ break;
+
+ case -1:
+ /*
+ * We failed to set up to use it, or the kernel
+ * supports it, but we failed to enable it.
+ * status has been set to the error status to
+ * return and, if it's PCAP_ERROR, handle->errbuf
+ * contains the error message.
+ */
+ goto fail;
+ }
+ }
+ else if (status == 0) {
+ /* Non-fatal error; try old way */
+ if ((status = activate_old(handle)) != 1) {
+ /*
+ * Both methods to open the packet socket failed.
+ * Tidy up and report our failure (handle->errbuf
+ * is expected to be set by the functions above).
+ */
+ goto fail;
+ }
+ }
+
+ /*
+ * We set up the socket, but not with memory-mapped access.
+ */
+ status = 0;
+ if (handle->opt.buffer_size != 0) {
+ /*
+ * Set the socket buffer size to the specified value.
+ */
+ if (setsockopt(handle->fd, SOL_SOCKET, SO_RCVBUF,
+ &handle->opt.buffer_size,
+ sizeof(handle->opt.buffer_size)) == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "SO_RCVBUF: %s", pcap_strerror(errno));
+ status = PCAP_ERROR;
+ goto fail;
+ }
+ }
+
+ /* Allocate the buffer */
+
+ handle->buffer = malloc(handle->bufsize + handle->offset);
+ if (!handle->buffer) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "malloc: %s", pcap_strerror(errno));
+ status = PCAP_ERROR;
+ goto fail;
+ }
+
+ /*
+ * "handle->fd" is a socket, so "select()" and "poll()"
+ * should work on it.
+ */
+ handle->selectable_fd = handle->fd;
+
+ return status;
+
+fail:
+ pcap_cleanup_linux(handle);
+ return status;
+}
+
+/*
+ * Read at most max_packets from the capture stream and call the callback
+ * for each of them. Returns the number of packets handled or -1 if an
+ * error occured.
+ */
+static int
+pcap_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
+{
+ /*
+ * Currently, on Linux only one packet is delivered per read,
+ * so we don't loop.
+ */
+ return pcap_read_packet(handle, callback, user);
+}
+
+/*
+ * Read a packet from the socket calling the handler provided by
+ * the user. Returns the number of packets received or -1 if an
+ * error occured.
+ */
+static int
+pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata)
+{
+ u_char *bp;
+ int offset;
+#ifdef HAVE_PF_PACKET_SOCKETS
+ struct sockaddr_ll from;
+ struct sll_header *hdrp;
+#else
+ struct sockaddr from;
+#endif
+#if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI)
+ struct iovec iov;
+ struct msghdr msg;
+ struct cmsghdr *cmsg;
+ union {
+ struct cmsghdr cmsg;
+ char buf[CMSG_SPACE(sizeof(struct tpacket_auxdata))];
+ } cmsg_buf;
+#else /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */
+ socklen_t fromlen;
+#endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */
+ int packet_len, caplen;
+ struct pcap_pkthdr pcap_header;
+
+#ifdef HAVE_PF_PACKET_SOCKETS
+ /*
+ * If this is a cooked device, leave extra room for a
+ * fake packet header.
+ */
+ if (handle->md.cooked)
+ offset = SLL_HDR_LEN;
+ else
+ offset = 0;
+#else
+ /*
+ * This system doesn't have PF_PACKET sockets, so it doesn't
+ * support cooked devices.
+ */
+ offset = 0;
+#endif
+
+ /*
+ * Receive a single packet from the kernel.
+ * We ignore EINTR, as that might just be due to a signal
+ * being delivered - if the signal should interrupt the
+ * loop, the signal handler should call pcap_breakloop()
+ * to set handle->break_loop (we ignore it on other
+ * platforms as well).
+ * We also ignore ENETDOWN, so that we can continue to
+ * capture traffic if the interface goes down and comes
+ * back up again; comments in the kernel indicate that
+ * we'll just block waiting for packets if we try to
+ * receive from a socket that delivered ENETDOWN, and,
+ * if we're using a memory-mapped buffer, we won't even
+ * get notified of "network down" events.
+ */
+ bp = handle->buffer + handle->offset;
+
+#if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI)
+ msg.msg_name = &from;
+ msg.msg_namelen = sizeof(from);
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+ msg.msg_control = &cmsg_buf;
+ msg.msg_controllen = sizeof(cmsg_buf);
+ msg.msg_flags = 0;
+
+ iov.iov_len = handle->bufsize - offset;
+ iov.iov_base = bp + offset;
+#endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */
+
+ do {
+ /*
+ * Has "pcap_breakloop()" been called?
+ */
+ if (handle->break_loop) {
+ /*
+ * Yes - clear the flag that indicates that it has,
+ * and return PCAP_ERROR_BREAK as an indication that
+ * we were told to break out of the loop.
+ */
+ handle->break_loop = 0;
+ return PCAP_ERROR_BREAK;
+ }
+
+#if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI)
+ packet_len = recvmsg(handle->fd, &msg, MSG_TRUNC);
+#else /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */
+ fromlen = sizeof(from);
+ packet_len = recvfrom(
+ handle->fd, bp + offset,
+ handle->bufsize - offset, MSG_TRUNC,
+ (struct sockaddr *) &from, &fromlen);
+#endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */
+ } while (packet_len == -1 && errno == EINTR);
+
+ /* Check if an error occured */
+
+ if (packet_len == -1) {
+ switch (errno) {
+
+ case EAGAIN:
+ return 0; /* no packet there */
+
+ case ENETDOWN:
+ /*
+ * The device on which we're capturing went away.
+ *
+ * XXX - we should really return
+ * PCAP_ERROR_IFACE_NOT_UP, but pcap_dispatch()
+ * etc. aren't defined to return that.
+ */
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "The interface went down");
+ return PCAP_ERROR;
+
+ default:
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "recvfrom: %s", pcap_strerror(errno));
+ return PCAP_ERROR;
+ }
+ }
+
+#ifdef HAVE_PF_PACKET_SOCKETS
+ if (!handle->md.sock_packet) {
+ /*
+ * Unfortunately, there is a window between socket() and
+ * bind() where the kernel may queue packets from any
+ * interface. If we're bound to a particular interface,
+ * discard packets not from that interface.
+ *
+ * (If socket filters are supported, we could do the
+ * same thing we do when changing the filter; however,
+ * that won't handle packet sockets without socket
+ * filter support, and it's a bit more complicated.
+ * It would save some instructions per packet, however.)
+ */
+ if (handle->md.ifindex != -1 &&
+ from.sll_ifindex != handle->md.ifindex)
+ return 0;
+
+ /*
+ * Do checks based on packet direction.
+ * We can only do this if we're using PF_PACKET; the
+ * address returned for SOCK_PACKET is a "sockaddr_pkt"
+ * which lacks the relevant packet type information.
+ */
+ if (from.sll_pkttype == PACKET_OUTGOING) {
+ /*
+ * Outgoing packet.
+ * If this is from the loopback device, reject it;
+ * we'll see the packet as an incoming packet as well,
+ * and we don't want to see it twice.
+ */
+ if (from.sll_ifindex == handle->md.lo_ifindex)
+ return 0;
+
+ /*
+ * If the user only wants incoming packets, reject it.
+ */
+ if (handle->direction == PCAP_D_IN)
+ return 0;
+ } else {
+ /*
+ * Incoming packet.
+ * If the user only wants outgoing packets, reject it.
+ */
+ if (handle->direction == PCAP_D_OUT)
+ return 0;
+ }
+ }
+#endif
+
+#ifdef HAVE_PF_PACKET_SOCKETS
+ /*
+ * If this is a cooked device, fill in the fake packet header.
+ */
+ if (handle->md.cooked) {
+ /*
+ * Add the length of the fake header to the length
+ * of packet data we read.
+ */
+ packet_len += SLL_HDR_LEN;
+
+ hdrp = (struct sll_header *)bp;
+ hdrp->sll_pkttype = map_packet_type_to_sll_type(from.sll_pkttype);
+ hdrp->sll_hatype = htons(from.sll_hatype);
+ hdrp->sll_halen = htons(from.sll_halen);
+ memcpy(hdrp->sll_addr, from.sll_addr,
+ (from.sll_halen > SLL_ADDRLEN) ?
+ SLL_ADDRLEN :
+ from.sll_halen);
+ hdrp->sll_protocol = from.sll_protocol;
+ }
+
+#if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI)
+ if (handle->md.vlan_offset != -1) {
+ for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
+ struct tpacket_auxdata *aux;
+ unsigned int len;
+ struct vlan_tag *tag;
+
+ if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct tpacket_auxdata)) ||
+ cmsg->cmsg_level != SOL_PACKET ||
+ cmsg->cmsg_type != PACKET_AUXDATA)
+ continue;
+
+ aux = (struct tpacket_auxdata *)CMSG_DATA(cmsg);
+#if defined(TP_STATUS_VLAN_VALID)
+ if ((aux->tp_vlan_tci == 0) && !(aux->tp_status & TP_STATUS_VLAN_VALID))
+#else
+ if (aux->tp_vlan_tci == 0) /* this is ambigious but without the
+ TP_STATUS_VLAN_VALID flag, there is
+ nothing that we can do */
+#endif
+ continue;
+
+ len = packet_len > iov.iov_len ? iov.iov_len : packet_len;
+ if (len < (unsigned int) handle->md.vlan_offset)
+ break;
+
+ bp -= VLAN_TAG_LEN;
+ memmove(bp, bp + VLAN_TAG_LEN, handle->md.vlan_offset);
+
+ tag = (struct vlan_tag *)(bp + handle->md.vlan_offset);
+ tag->vlan_tpid = htons(ETH_P_8021Q);
+ tag->vlan_tci = htons(aux->tp_vlan_tci);
+
+ packet_len += VLAN_TAG_LEN;
+ }
+ }
+#endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */
+#endif /* HAVE_PF_PACKET_SOCKETS */
+
+ /*
+ * XXX: According to the kernel source we should get the real
+ * packet len if calling recvfrom with MSG_TRUNC set. It does
+ * not seem to work here :(, but it is supported by this code
+ * anyway.
+ * To be honest the code RELIES on that feature so this is really
+ * broken with 2.2.x kernels.
+ * I spend a day to figure out what's going on and I found out
+ * that the following is happening:
+ *
+ * The packet comes from a random interface and the packet_rcv
+ * hook is called with a clone of the packet. That code inserts
+ * the packet into the receive queue of the packet socket.
+ * If a filter is attached to that socket that filter is run
+ * first - and there lies the problem. The default filter always
+ * cuts the packet at the snaplen:
+ *
+ * # tcpdump -d
+ * (000) ret #68
+ *
+ * So the packet filter cuts down the packet. The recvfrom call
+ * says "hey, it's only 68 bytes, it fits into the buffer" with
+ * the result that we don't get the real packet length. This
+ * is valid at least until kernel 2.2.17pre6.
+ *
+ * We currently handle this by making a copy of the filter
+ * program, fixing all "ret" instructions with non-zero
+ * operands to have an operand of 65535 so that the filter
+ * doesn't truncate the packet, and supplying that modified
+ * filter to the kernel.
+ */
+
+ caplen = packet_len;
+ if (caplen > handle->snapshot)
+ caplen = handle->snapshot;
+
+ /* Run the packet filter if not using kernel filter */
+ if (!handle->md.use_bpf && handle->fcode.bf_insns) {
+ if (bpf_filter(handle->fcode.bf_insns, bp,
+ packet_len, caplen) == 0)
+ {
+ /* rejected by filter */
+ return 0;
+ }
+ }
+
+ /* Fill in our own header data */
+
+ if (ioctl(handle->fd, SIOCGSTAMP, &pcap_header.ts) == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "SIOCGSTAMP: %s", pcap_strerror(errno));
+ return PCAP_ERROR;
+ }
+ pcap_header.caplen = caplen;
+ pcap_header.len = packet_len;
+
+ /*
+ * Count the packet.
+ *
+ * Arguably, we should count them before we check the filter,
+ * as on many other platforms "ps_recv" counts packets
+ * handed to the filter rather than packets that passed
+ * the filter, but if filtering is done in the kernel, we
+ * can't get a count of packets that passed the filter,
+ * and that would mean the meaning of "ps_recv" wouldn't
+ * be the same on all Linux systems.
+ *
+ * XXX - it's not the same on all systems in any case;
+ * ideally, we should have a "get the statistics" call
+ * that supplies more counts and indicates which of them
+ * it supplies, so that we supply a count of packets
+ * handed to the filter only on platforms where that
+ * information is available.
+ *
+ * We count them here even if we can get the packet count
+ * from the kernel, as we can only determine at run time
+ * whether we'll be able to get it from the kernel (if
+ * HAVE_TPACKET_STATS isn't defined, we can't get it from
+ * the kernel, but if it is defined, the library might
+ * have been built with a 2.4 or later kernel, but we
+ * might be running on a 2.2[.x] kernel without Alexey
+ * Kuznetzov's turbopacket patches, and thus the kernel
+ * might not be able to supply those statistics). We
+ * could, I guess, try, when opening the socket, to get
+ * the statistics, and if we can not increment the count
+ * here, but it's not clear that always incrementing
+ * the count is more expensive than always testing a flag
+ * in memory.
+ *
+ * We keep the count in "md.packets_read", and use that for
+ * "ps_recv" if we can't get the statistics from the kernel.
+ * We do that because, if we *can* get the statistics from
+ * the kernel, we use "md.stat.ps_recv" and "md.stat.ps_drop"
+ * as running counts, as reading the statistics from the
+ * kernel resets the kernel statistics, and if we directly
+ * increment "md.stat.ps_recv" here, that means it will
+ * count packets *twice* on systems where we can get kernel
+ * statistics - once here, and once in pcap_stats_linux().
+ */
+ handle->md.packets_read++;
+
+ /* Call the user supplied callback function */
+ callback(userdata, &pcap_header, bp);
+
+ return 1;
+}
+
+static int
+pcap_inject_linux(pcap_t *handle, const void *buf, size_t size)
+{
+ int ret;
+
+#ifdef HAVE_PF_PACKET_SOCKETS
+ if (!handle->md.sock_packet) {
+ /* PF_PACKET socket */
+ if (handle->md.ifindex == -1) {
+ /*
+ * We don't support sending on the "any" device.
+ */
+ strlcpy(handle->errbuf,
+ "Sending packets isn't supported on the \"any\" device",
+ PCAP_ERRBUF_SIZE);
+ return (-1);
+ }
+
+ if (handle->md.cooked) {
+ /*
+ * We don't support sending on the "any" device.
+ *
+ * XXX - how do you send on a bound cooked-mode
+ * socket?
+ * Is a "sendto()" required there?
+ */
+ strlcpy(handle->errbuf,
+ "Sending packets isn't supported in cooked mode",
+ PCAP_ERRBUF_SIZE);
+ return (-1);
+ }
+ }
+#endif
+
+ ret = send(handle->fd, buf, size, 0);
+ if (ret == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "send: %s",
+ pcap_strerror(errno));
+ return (-1);
+ }
+ return (ret);
+}
+
+/*
+ * Get the statistics for the given packet capture handle.
+ * Reports the number of dropped packets iff the kernel supports
+ * the PACKET_STATISTICS "getsockopt()" argument (2.4 and later
+ * kernels, and 2.2[.x] kernels with Alexey Kuznetzov's turbopacket
+ * patches); otherwise, that information isn't available, and we lie
+ * and report 0 as the count of dropped packets.
+ */
+static int
+pcap_stats_linux(pcap_t *handle, struct pcap_stat *stats)
+{
+#ifdef HAVE_TPACKET_STATS
+ struct tpacket_stats kstats;
+ socklen_t len = sizeof (struct tpacket_stats);
+#endif
+
+ long if_dropped = 0;
+
+ /*
+ * To fill in ps_ifdrop, we parse /proc/net/dev for the number
+ */
+ if (handle->opt.promisc)
+ {
+ if_dropped = handle->md.proc_dropped;
+ handle->md.proc_dropped = linux_if_drops(handle->md.device);
+ handle->md.stat.ps_ifdrop += (handle->md.proc_dropped - if_dropped);
+ }
+
+#ifdef HAVE_TPACKET_STATS
+ /*
+ * Try to get the packet counts from the kernel.
+ */
+ if (getsockopt(handle->fd, SOL_PACKET, PACKET_STATISTICS,
+ &kstats, &len) > -1) {
+ /*
+ * On systems where the PACKET_STATISTICS "getsockopt()"
+ * argument is supported on PF_PACKET sockets:
+ *
+ * "ps_recv" counts only packets that *passed* the
+ * filter, not packets that didn't pass the filter.
+ * This includes packets later dropped because we
+ * ran out of buffer space.
+ *
+ * "ps_drop" counts packets dropped because we ran
+ * out of buffer space. It doesn't count packets
+ * dropped by the interface driver. It counts only
+ * packets that passed the filter.
+ *
+ * See above for ps_ifdrop.
+ *
+ * Both statistics include packets not yet read from
+ * the kernel by libpcap, and thus not yet seen by
+ * the application.
+ *
+ * In "linux/net/packet/af_packet.c", at least in the
+ * 2.4.9 kernel, "tp_packets" is incremented for every
+ * packet that passes the packet filter *and* is
+ * successfully queued on the socket; "tp_drops" is
+ * incremented for every packet dropped because there's
+ * not enough free space in the socket buffer.
+ *
+ * When the statistics are returned for a PACKET_STATISTICS
+ * "getsockopt()" call, "tp_drops" is added to "tp_packets",
+ * so that "tp_packets" counts all packets handed to
+ * the PF_PACKET socket, including packets dropped because
+ * there wasn't room on the socket buffer - but not
+ * including packets that didn't pass the filter.
+ *
+ * In the BSD BPF, the count of received packets is
+ * incremented for every packet handed to BPF, regardless
+ * of whether it passed the filter.
+ *
+ * We can't make "pcap_stats()" work the same on both
+ * platforms, but the best approximation is to return
+ * "tp_packets" as the count of packets and "tp_drops"
+ * as the count of drops.
+ *
+ * Keep a running total because each call to
+ * getsockopt(handle->fd, SOL_PACKET, PACKET_STATISTICS, ....
+ * resets the counters to zero.
+ */
+ handle->md.stat.ps_recv += kstats.tp_packets;
+ handle->md.stat.ps_drop += kstats.tp_drops;
+ *stats = handle->md.stat;
+ return 0;
+ }
+ else
+ {
+ /*
+ * If the error was EOPNOTSUPP, fall through, so that
+ * if you build the library on a system with
+ * "struct tpacket_stats" and run it on a system
+ * that doesn't, it works as it does if the library
+ * is built on a system without "struct tpacket_stats".
+ */
+ if (errno != EOPNOTSUPP) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "pcap_stats: %s", pcap_strerror(errno));
+ return -1;
+ }
+ }
+#endif
+ /*
+ * On systems where the PACKET_STATISTICS "getsockopt()" argument
+ * is not supported on PF_PACKET sockets:
+ *
+ * "ps_recv" counts only packets that *passed* the filter,
+ * not packets that didn't pass the filter. It does not
+ * count packets dropped because we ran out of buffer
+ * space.
+ *
+ * "ps_drop" is not supported.
+ *
+ * "ps_ifdrop" is supported. It will return the number
+ * of drops the interface reports in /proc/net/dev,
+ * if that is available.
+ *
+ * "ps_recv" doesn't include packets not yet read from
+ * the kernel by libpcap.
+ *
+ * We maintain the count of packets processed by libpcap in
+ * "md.packets_read", for reasons described in the comment
+ * at the end of pcap_read_packet(). We have no idea how many
+ * packets were dropped by the kernel buffers -- but we know
+ * how many the interface dropped, so we can return that.
+ */
+
+ stats->ps_recv = handle->md.packets_read;
+ stats->ps_drop = 0;
+ stats->ps_ifdrop = handle->md.stat.ps_ifdrop;
+ return 0;
+}
+
+/*
+ * Get from "/sys/class/net" all interfaces listed there; if they're
+ * already in the list of interfaces we have, that won't add another
+ * instance, but if they're not, that'll add them.
+ *
+ * We don't bother getting any addresses for them; it appears you can't
+ * use SIOCGIFADDR on Linux to get IPv6 addresses for interfaces, and,
+ * although some other types of addresses can be fetched with SIOCGIFADDR,
+ * we don't bother with them for now.
+ *
+ * We also don't fail if we couldn't open "/sys/class/net"; we just leave
+ * the list of interfaces as is, and return 0, so that we can try
+ * scanning /proc/net/dev.
+ */
+static int
+scan_sys_class_net(pcap_if_t **devlistp, char *errbuf)
+{
+ DIR *sys_class_net_d;
+ int fd;
+ struct dirent *ent;
+ char subsystem_path[PATH_MAX+1];
+ struct stat statb;
+ char *p;
+ char name[512]; /* XXX - pick a size */
+ char *q, *saveq;
+ struct ifreq ifrflags;
+ int ret = 1;
+
+ sys_class_net_d = opendir("/sys/class/net");
+ if (sys_class_net_d == NULL) {
+ /*
+ * Don't fail if it doesn't exist at all.
+ */
+ if (errno == ENOENT)
+ return (0);
+
+ /*
+ * Fail if we got some other error.
+ */
+ (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
+ "Can't open /sys/class/net: %s", pcap_strerror(errno));
+ return (-1);
+ }
+
+ /*
+ * Create a socket from which to fetch interface information.
+ */
+ fd = socket(AF_INET, SOCK_DGRAM, 0);
+ if (fd < 0) {
+ (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
+ "socket: %s", pcap_strerror(errno));
+ (void)closedir(sys_class_net_d);
+ return (-1);
+ }
+
+ for (;;) {
+ errno = 0;
+ ent = readdir(sys_class_net_d);
+ if (ent == NULL) {
+ /*
+ * Error or EOF; if errno != 0, it's an error.
+ */
+ break;
+ }
+
+ /*
+ * Ignore "." and "..".
+ */
+ if (strcmp(ent->d_name, ".") == 0 ||
+ strcmp(ent->d_name, "..") == 0)
+ continue;
+
+ /*
+ * Ignore plain files; they do not have subdirectories
+ * and thus have no attributes.
+ */
+ if (ent->d_type == DT_REG)
+ continue;
+
+ /*
+ * Is there an "ifindex" file under that name?
+ * (We don't care whether it's a directory or
+ * a symlink; older kernels have directories
+ * for devices, newer kernels have symlinks to
+ * directories.)
+ */
+ snprintf(subsystem_path, sizeof subsystem_path,
+ "/sys/class/net/%s/ifindex", ent->d_name);
+ if (lstat(subsystem_path, &statb) != 0) {
+ /*
+ * Stat failed. Either there was an error
+ * other than ENOENT, and we don't know if
+ * this is an interface, or it's ENOENT,
+ * and either some part of "/sys/class/net/{if}"
+ * disappeared, in which case it probably means
+ * the interface disappeared, or there's no
+ * "ifindex" file, which means it's not a
+ * network interface.
+ */
+ continue;
+ }
+
+ /*
+ * Get the interface name.
+ */
+ p = &ent->d_name[0];
+ q = &name[0];
+ while (*p != '\0' && isascii(*p) && !isspace(*p)) {
+ if (*p == ':') {
+ /*
+ * This could be the separator between a
+ * name and an alias number, or it could be
+ * the separator between a name with no
+ * alias number and the next field.
+ *
+ * If there's a colon after digits, it
+ * separates the name and the alias number,
+ * otherwise it separates the name and the
+ * next field.
+ */
+ saveq = q;
+ while (isascii(*p) && isdigit(*p))
+ *q++ = *p++;
+ if (*p != ':') {
+ /*
+ * That was the next field,
+ * not the alias number.
+ */
+ q = saveq;
+ }
+ break;
+ } else
+ *q++ = *p++;
+ }
+ *q = '\0';
+
+ /*
+ * Get the flags for this interface, and skip it if
+ * it's not up.
+ */
+ strncpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name));
+ if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
+ if (errno == ENXIO || errno == ENODEV)
+ continue;
+ (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
+ "SIOCGIFFLAGS: %.*s: %s",
+ (int)sizeof(ifrflags.ifr_name),
+ ifrflags.ifr_name,
+ pcap_strerror(errno));
+ ret = -1;
+ break;
+ }
+ if (!(ifrflags.ifr_flags & IFF_UP))
+ continue;
+
+ /*
+ * Add an entry for this interface, with no addresses.
+ */
+ if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL,
+ errbuf) == -1) {
+ /*
+ * Failure.
+ */
+ ret = -1;
+ break;
+ }
+ }
+ if (ret != -1) {
+ /*
+ * Well, we didn't fail for any other reason; did we
+ * fail due to an error reading the directory?
+ */
+ if (errno != 0) {
+ (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
+ "Error reading /sys/class/net: %s",
+ pcap_strerror(errno));
+ ret = -1;
+ }
+ }
+
+ (void)close(fd);
+ (void)closedir(sys_class_net_d);
+ return (ret);
+}
+
+/*
+ * Get from "/proc/net/dev" all interfaces listed there; if they're
+ * already in the list of interfaces we have, that won't add another
+ * instance, but if they're not, that'll add them.
+ *
+ * See comments from scan_sys_class_net().
+ */
+static int
+scan_proc_net_dev(pcap_if_t **devlistp, char *errbuf)
+{
+ FILE *proc_net_f;
+ int fd;
+ char linebuf[512];
+ int linenum;
+ char *p;
+ char name[512]; /* XXX - pick a size */
+ char *q, *saveq;
+ struct ifreq ifrflags;
+ int ret = 0;
+
+ proc_net_f = fopen("/proc/net/dev", "r");
+ if (proc_net_f == NULL) {
+ /*
+ * Don't fail if it doesn't exist at all.
+ */
+ if (errno == ENOENT)
+ return (0);
+
+ /*
+ * Fail if we got some other error.
+ */
+ (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
+ "Can't open /proc/net/dev: %s", pcap_strerror(errno));
+ return (-1);
+ }
+
+ /*
+ * Create a socket from which to fetch interface information.
+ */
+ fd = socket(AF_INET, SOCK_DGRAM, 0);
+ if (fd < 0) {
+ (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
+ "socket: %s", pcap_strerror(errno));
+ (void)fclose(proc_net_f);
+ return (-1);
+ }
+
+ for (linenum = 1;
+ fgets(linebuf, sizeof linebuf, proc_net_f) != NULL; linenum++) {
+ /*
+ * Skip the first two lines - they're headers.
+ */
+ if (linenum <= 2)
+ continue;
+
+ p = &linebuf[0];
+
+ /*
+ * Skip leading white space.
+ */
+ while (*p != '\0' && isascii(*p) && isspace(*p))
+ p++;
+ if (*p == '\0' || *p == '\n')
+ continue; /* blank line */
+
+ /*
+ * Get the interface name.
+ */
+ q = &name[0];
+ while (*p != '\0' && isascii(*p) && !isspace(*p)) {
+ if (*p == ':') {
+ /*
+ * This could be the separator between a
+ * name and an alias number, or it could be
+ * the separator between a name with no
+ * alias number and the next field.
+ *
+ * If there's a colon after digits, it
+ * separates the name and the alias number,
+ * otherwise it separates the name and the
+ * next field.
+ */
+ saveq = q;
+ while (isascii(*p) && isdigit(*p))
+ *q++ = *p++;
+ if (*p != ':') {
+ /*
+ * That was the next field,
+ * not the alias number.
+ */
+ q = saveq;
+ }
+ break;
+ } else
+ *q++ = *p++;
+ }
+ *q = '\0';
+
+ /*
+ * Get the flags for this interface, and skip it if
+ * it's not up.
+ */
+ strncpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name));
+ if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
+ if (errno == ENXIO)
+ continue;
+ (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
+ "SIOCGIFFLAGS: %.*s: %s",
+ (int)sizeof(ifrflags.ifr_name),
+ ifrflags.ifr_name,
+ pcap_strerror(errno));
+ ret = -1;
+ break;
+ }
+ if (!(ifrflags.ifr_flags & IFF_UP))
+ continue;
+
+ /*
+ * Add an entry for this interface, with no addresses.
+ */
+ if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL,
+ errbuf) == -1) {
+ /*
+ * Failure.
+ */
+ ret = -1;
+ break;
+ }
+ }
+ if (ret != -1) {
+ /*
+ * Well, we didn't fail for any other reason; did we
+ * fail due to an error reading the file?
+ */
+ if (ferror(proc_net_f)) {
+ (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
+ "Error reading /proc/net/dev: %s",
+ pcap_strerror(errno));
+ ret = -1;
+ }
+ }
+
+ (void)close(fd);
+ (void)fclose(proc_net_f);
+ return (ret);
+}
+
+/*
+ * Description string for the "any" device.
+ */
+static const char any_descr[] = "Pseudo-device that captures on all interfaces";
+
+int
+pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
+{
+ int ret;
+
+ /*
+ * Read "/sys/class/net", and add to the list of interfaces all
+ * interfaces listed there that we don't already have, because,
+ * on Linux, SIOCGIFCONF reports only interfaces with IPv4 addresses,
+ * and even getifaddrs() won't return information about
+ * interfaces with no addresses, so you need to read "/sys/class/net"
+ * to get the names of the rest of the interfaces.
+ */
+ ret = scan_sys_class_net(alldevsp, errbuf);
+ if (ret == -1)
+ return (-1); /* failed */
+ if (ret == 0) {
+ /*
+ * No /sys/class/net; try reading /proc/net/dev instead.
+ */
+ if (scan_proc_net_dev(alldevsp, errbuf) == -1)
+ return (-1);
+ }
+
+ /*
+ * Add the "any" device.
+ */
+ if (pcap_add_if(alldevsp, "any", 0, any_descr, errbuf) < 0)
+ return (-1);
+
+#ifdef HAVE_DAG_API
+ /*
+ * Add DAG devices.
+ */
+ if (dag_platform_finddevs(alldevsp, errbuf) < 0)
+ return (-1);
+#endif /* HAVE_DAG_API */
+
+#ifdef HAVE_SEPTEL_API
+ /*
+ * Add Septel devices.
+ */
+ if (septel_platform_finddevs(alldevsp, errbuf) < 0)
+ return (-1);
+#endif /* HAVE_SEPTEL_API */
+
+#ifdef HAVE_SNF_API
+ if (snf_platform_finddevs(alldevsp, errbuf) < 0)
+ return (-1);
+#endif /* HAVE_SNF_API */
+
+#ifdef PCAP_SUPPORT_BT
+ /*
+ * Add Bluetooth devices.
+ */
+ if (bt_platform_finddevs(alldevsp, errbuf) < 0)
+ return (-1);
+#endif
+
+#ifdef PCAP_SUPPORT_USB
+ /*
+ * Add USB devices.
+ */
+ if (usb_platform_finddevs(alldevsp, errbuf) < 0)
+ return (-1);
+#endif
+
+#ifdef PCAP_SUPPORT_NETFILTER
+ /*
+ * Add netfilter devices.
+ */
+ if (netfilter_platform_finddevs(alldevsp, errbuf) < 0)
+ return (-1);
+#endif
+
+#if PCAP_SUPPORT_CANUSB
+ if (canusb_platform_finddevs(alldevsp, errbuf) < 0)
+ return (-1);
+#endif
+
+ return (0);
+}
+
+/*
+ * Attach the given BPF code to the packet capture device.
+ */
+static int
+pcap_setfilter_linux_common(pcap_t *handle, struct bpf_program *filter,
+ int is_mmapped)
+{
+#ifdef SO_ATTACH_FILTER
+ struct sock_fprog fcode;
+ int can_filter_in_kernel;
+ int err = 0;
+#endif
+
+ if (!handle)
+ return -1;
+ if (!filter) {
+ strncpy(handle->errbuf, "setfilter: No filter specified",
+ PCAP_ERRBUF_SIZE);
+ return -1;
+ }
+
+ /* Make our private copy of the filter */
+
+ if (install_bpf_program(handle, filter) < 0)
+ /* install_bpf_program() filled in errbuf */
+ return -1;
+
+ /*
+ * Run user level packet filter by default. Will be overriden if
+ * installing a kernel filter succeeds.
+ */
+ handle->md.use_bpf = 0;
+
+ /* Install kernel level filter if possible */
+
+#ifdef SO_ATTACH_FILTER
+#ifdef USHRT_MAX
+ if (handle->fcode.bf_len > USHRT_MAX) {
+ /*
+ * fcode.len is an unsigned short for current kernel.
+ * I have yet to see BPF-Code with that much
+ * instructions but still it is possible. So for the
+ * sake of correctness I added this check.
+ */
+ fprintf(stderr, "Warning: Filter too complex for kernel\n");
+ fcode.len = 0;
+ fcode.filter = NULL;
+ can_filter_in_kernel = 0;
+ } else
+#endif /* USHRT_MAX */
+ {
+ /*
+ * Oh joy, the Linux kernel uses struct sock_fprog instead
+ * of struct bpf_program and of course the length field is
+ * of different size. Pointed out by Sebastian
+ *
+ * Oh, and we also need to fix it up so that all "ret"
+ * instructions with non-zero operands have 65535 as the
+ * operand if we're not capturing in memory-mapped modee,
+ * and so that, if we're in cooked mode, all memory-reference
+ * instructions use special magic offsets in references to
+ * the link-layer header and assume that the link-layer
+ * payload begins at 0; "fix_program()" will do that.
+ */
+ switch (fix_program(handle, &fcode, is_mmapped)) {
+
+ case -1:
+ default:
+ /*
+ * Fatal error; just quit.
+ * (The "default" case shouldn't happen; we
+ * return -1 for that reason.)
+ */
+ return -1;
+
+ case 0:
+ /*
+ * The program performed checks that we can't make
+ * work in the kernel.
+ */
+ can_filter_in_kernel = 0;
+ break;
+
+ case 1:
+ /*
+ * We have a filter that'll work in the kernel.
+ */
+ can_filter_in_kernel = 1;
+ break;
+ }
+ }
+
+ /*
+ * NOTE: at this point, we've set both the "len" and "filter"
+ * fields of "fcode". As of the 2.6.32.4 kernel, at least,
+ * those are the only members of the "sock_fprog" structure,
+ * so we initialize every member of that structure.
+ *
+ * If there is anything in "fcode" that is not initialized,
+ * it is either a field added in a later kernel, or it's
+ * padding.
+ *
+ * If a new field is added, this code needs to be updated
+ * to set it correctly.
+ *
+ * If there are no other fields, then:
+ *
+ * if the Linux kernel looks at the padding, it's
+ * buggy;
+ *
+ * if the Linux kernel doesn't look at the padding,
+ * then if some tool complains that we're passing
+ * uninitialized data to the kernel, then the tool
+ * is buggy and needs to understand that it's just
+ * padding.
+ */
+ if (can_filter_in_kernel) {
+ if ((err = set_kernel_filter(handle, &fcode)) == 0)
+ {
+ /* Installation succeded - using kernel filter. */
+ handle->md.use_bpf = 1;
+ }
+ else if (err == -1) /* Non-fatal error */
+ {
+ /*
+ * Print a warning if we weren't able to install
+ * the filter for a reason other than "this kernel
+ * isn't configured to support socket filters.
+ */
+ if (errno != ENOPROTOOPT && errno != EOPNOTSUPP) {
+ fprintf(stderr,
+ "Warning: Kernel filter failed: %s\n",
+ pcap_strerror(errno));
+ }
+ }
+ }
+
+ /*
+ * If we're not using the kernel filter, get rid of any kernel
+ * filter that might've been there before, e.g. because the
+ * previous filter could work in the kernel, or because some other
+ * code attached a filter to the socket by some means other than
+ * calling "pcap_setfilter()". Otherwise, the kernel filter may
+ * filter out packets that would pass the new userland filter.
+ */
+ if (!handle->md.use_bpf)
+ reset_kernel_filter(handle);
+
+ /*
+ * Free up the copy of the filter that was made by "fix_program()".
+ */
+ if (fcode.filter != NULL)
+ free(fcode.filter);
+
+ if (err == -2)
+ /* Fatal error */
+ return -1;
+#endif /* SO_ATTACH_FILTER */
+
+ return 0;
+}
+
+static int
+pcap_setfilter_linux(pcap_t *handle, struct bpf_program *filter)
+{
+ return pcap_setfilter_linux_common(handle, filter, 0);
+}
+
+
+/*
+ * Set direction flag: Which packets do we accept on a forwarding
+ * single device? IN, OUT or both?
+ */
+static int
+pcap_setdirection_linux(pcap_t *handle, pcap_direction_t d)
+{
+#ifdef HAVE_PF_PACKET_SOCKETS
+ if (!handle->md.sock_packet) {
+ handle->direction = d;
+ return 0;
+ }
+#endif
+ /*
+ * We're not using PF_PACKET sockets, so we can't determine
+ * the direction of the packet.
+ */
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "Setting direction is not supported on SOCK_PACKET sockets");
+ return -1;
+}
+
+#ifdef HAVE_PF_PACKET_SOCKETS
+/*
+ * Map the PACKET_ value to a LINUX_SLL_ value; we
+ * want the same numerical value to be used in
+ * the link-layer header even if the numerical values
+ * for the PACKET_ #defines change, so that programs
+ * that look at the packet type field will always be
+ * able to handle DLT_LINUX_SLL captures.
+ */
+static short int
+map_packet_type_to_sll_type(short int sll_pkttype)
+{
+ switch (sll_pkttype) {
+
+ case PACKET_HOST:
+ return htons(LINUX_SLL_HOST);
+
+ case PACKET_BROADCAST:
+ return htons(LINUX_SLL_BROADCAST);
+
+ case PACKET_MULTICAST:
+ return htons(LINUX_SLL_MULTICAST);
+
+ case PACKET_OTHERHOST:
+ return htons(LINUX_SLL_OTHERHOST);
+
+ case PACKET_OUTGOING:
+ return htons(LINUX_SLL_OUTGOING);
+
+ default:
+ return -1;
+ }
+}
+#endif
+
+static int
+is_wifi(int sock_fd
+#ifndef IW_MODE_MONITOR
+_U_
+#endif
+, const char *device)
+{
+ char *pathstr;
+ struct stat statb;
+#ifdef IW_MODE_MONITOR
+ char errbuf[PCAP_ERRBUF_SIZE];
+#endif
+
+ /*
+ * See if there's a sysfs wireless directory for it.
+ * If so, it's a wireless interface.
+ */
+ if (asprintf(&pathstr, "/sys/class/net/%s/wireless", device) == -1) {
+ /*
+ * Just give up here.
+ */
+ return 0;
+ }
+ if (stat(pathstr, &statb) == 0) {
+ free(pathstr);
+ return 1;
+ }
+ free(pathstr);
+
+#ifdef IW_MODE_MONITOR
+ /*
+ * OK, maybe it's not wireless, or maybe this kernel doesn't
+ * support sysfs. Try the wireless extensions.
+ */
+ if (has_wext(sock_fd, device, errbuf) == 1) {
+ /*
+ * It supports the wireless extensions, so it's a Wi-Fi
+ * device.
+ */
+ return 1;
+ }
+#endif
+ return 0;
+}
+
+/*
+ * Linux uses the ARP hardware type to identify the type of an
+ * interface. pcap uses the DLT_xxx constants for this. This
+ * function takes a pointer to a "pcap_t", and an ARPHRD_xxx
+ * constant, as arguments, and sets "handle->linktype" to the
+ * appropriate DLT_XXX constant and sets "handle->offset" to
+ * the appropriate value (to make "handle->offset" plus link-layer
+ * header length be a multiple of 4, so that the link-layer payload
+ * will be aligned on a 4-byte boundary when capturing packets).
+ * (If the offset isn't set here, it'll be 0; add code as appropriate
+ * for cases where it shouldn't be 0.)
+ *
+ * If "cooked_ok" is non-zero, we can use DLT_LINUX_SLL and capture
+ * in cooked mode; otherwise, we can't use cooked mode, so we have
+ * to pick some type that works in raw mode, or fail.
+ *
+ * Sets the link type to -1 if unable to map the type.
+ */
+static void map_arphrd_to_dlt(pcap_t *handle, int sock_fd, int arptype,
+ const char *device, int cooked_ok)
+{
+ static const char cdma_rmnet[] = "cdma_rmnet";
+
+ switch (arptype) {
+
+ case ARPHRD_ETHER:
+ /*
+ * For various annoying reasons having to do with DHCP
+ * software, some versions of Android give the mobile-
+ * phone-network interface an ARPHRD_ value of
+ * ARPHRD_ETHER, even though the packets supplied by
+ * that interface have no link-layer header, and begin
+ * with an IP header, so that the ARPHRD_ value should
+ * be ARPHRD_NONE.
+ *
+ * Detect those devices by checking the device name, and
+ * use DLT_RAW for them.
+ */
+ if (strncmp(device, cdma_rmnet, sizeof cdma_rmnet - 1) == 0) {
+ handle->linktype = DLT_RAW;
+ return;
+ }
+
+ /*
+ * Is this a real Ethernet device? If so, give it a
+ * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
+ * that an application can let you choose it, in case you're
+ * capturing DOCSIS traffic that a Cisco Cable Modem
+ * Termination System is putting out onto an Ethernet (it
+ * doesn't put an Ethernet header onto the wire, it puts raw
+ * DOCSIS frames out on the wire inside the low-level
+ * Ethernet framing).
+ *
+ * XXX - are there any other sorts of "fake Ethernet" that
+ * have ARPHRD_ETHER but that shouldn't offer DLT_DOCSIS as
+ * a Cisco CMTS won't put traffic onto it or get traffic
+ * bridged onto it? ISDN is handled in "activate_new()",
+ * as we fall back on cooked mode there, and we use
+ * is_wifi() to check for 802.11 devices; are there any
+ * others?
+ */
+ if (!is_wifi(sock_fd, device)) {
+ /*
+ * It's not a Wi-Fi device; offer DOCSIS.
+ */
+ handle->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
+ /*
+ * If that fails, just leave the list empty.
+ */
+ if (handle->dlt_list != NULL) {
+ handle->dlt_list[0] = DLT_EN10MB;
+ handle->dlt_list[1] = DLT_DOCSIS;
+ handle->dlt_count = 2;
+ }
+ }
+ /* FALLTHROUGH */
+
+ case ARPHRD_METRICOM:
+ case ARPHRD_LOOPBACK:
+ handle->linktype = DLT_EN10MB;
+ handle->offset = 2;
+ break;
+
+ case ARPHRD_EETHER:
+ handle->linktype = DLT_EN3MB;
+ break;
+
+ case ARPHRD_AX25:
+ handle->linktype = DLT_AX25_KISS;
+ break;
+
+ case ARPHRD_PRONET:
+ handle->linktype = DLT_PRONET;
+ break;
+
+ case ARPHRD_CHAOS:
handle->linktype = DLT_CHAOS;
break;
+#ifndef ARPHRD_CAN
+#define ARPHRD_CAN 280
+#endif
+ case ARPHRD_CAN:
+ handle->linktype = DLT_CAN_SOCKETCAN;
+ break;
+
+#ifndef ARPHRD_IEEE802_TR
+#define ARPHRD_IEEE802_TR 800 /* From Linux 2.4 */
+#endif
+ case ARPHRD_IEEE802_TR:
+ case ARPHRD_IEEE802:
+ handle->linktype = DLT_IEEE802;
+ handle->offset = 2;
+ break;
+
+ case ARPHRD_ARCNET:
+ handle->linktype = DLT_ARCNET_LINUX;
+ break;
+
+#ifndef ARPHRD_FDDI /* From Linux 2.2.13 */
+#define ARPHRD_FDDI 774
+#endif
+ case ARPHRD_FDDI:
+ handle->linktype = DLT_FDDI;
+ handle->offset = 3;
+ break;
+
+#ifndef ARPHRD_ATM /* FIXME: How to #include this? */
+#define ARPHRD_ATM 19
+#endif
+ case ARPHRD_ATM:
+ /*
+ * The Classical IP implementation in ATM for Linux
+ * supports both what RFC 1483 calls "LLC Encapsulation",
+ * in which each packet has an LLC header, possibly
+ * with a SNAP header as well, prepended to it, and
+ * what RFC 1483 calls "VC Based Multiplexing", in which
+ * different virtual circuits carry different network
+ * layer protocols, and no header is prepended to packets.
+ *
+ * They both have an ARPHRD_ type of ARPHRD_ATM, so
+ * you can't use the ARPHRD_ type to find out whether
+ * captured packets will have an LLC header, and,
+ * while there's a socket ioctl to *set* the encapsulation
+ * type, there's no ioctl to *get* the encapsulation type.
+ *
+ * This means that
+ *
+ * programs that dissect Linux Classical IP frames
+ * would have to check for an LLC header and,
+ * depending on whether they see one or not, dissect
+ * the frame as LLC-encapsulated or as raw IP (I
+ * don't know whether there's any traffic other than
+ * IP that would show up on the socket, or whether
+ * there's any support for IPv6 in the Linux
+ * Classical IP code);
+ *
+ * filter expressions would have to compile into
+ * code that checks for an LLC header and does
+ * the right thing.
+ *
+ * Both of those are a nuisance - and, at least on systems
+ * that support PF_PACKET sockets, we don't have to put
+ * up with those nuisances; instead, we can just capture
+ * in cooked mode. That's what we'll do, if we can.
+ * Otherwise, we'll just fail.
+ */
+ if (cooked_ok)
+ handle->linktype = DLT_LINUX_SLL;
+ else
+ handle->linktype = -1;
+ break;
+
+#ifndef ARPHRD_IEEE80211 /* From Linux 2.4.6 */
+#define ARPHRD_IEEE80211 801
+#endif
+ case ARPHRD_IEEE80211:
+ handle->linktype = DLT_IEEE802_11;
+ break;
+
+#ifndef ARPHRD_IEEE80211_PRISM /* From Linux 2.4.18 */
+#define ARPHRD_IEEE80211_PRISM 802
+#endif
+ case ARPHRD_IEEE80211_PRISM:
+ handle->linktype = DLT_PRISM_HEADER;
+ break;
+
+#ifndef ARPHRD_IEEE80211_RADIOTAP /* new */
+#define ARPHRD_IEEE80211_RADIOTAP 803
+#endif
+ case ARPHRD_IEEE80211_RADIOTAP:
+ handle->linktype = DLT_IEEE802_11_RADIO;
+ break;
+
+ case ARPHRD_PPP:
+ /*
+ * Some PPP code in the kernel supplies no link-layer
+ * header whatsoever to PF_PACKET sockets; other PPP
+ * code supplies PPP link-layer headers ("syncppp.c");
+ * some PPP code might supply random link-layer
+ * headers (PPP over ISDN - there's code in Ethereal,
+ * for example, to cope with PPP-over-ISDN captures
+ * with which the Ethereal developers have had to cope,
+ * heuristically trying to determine which of the
+ * oddball link-layer headers particular packets have).
+ *
+ * As such, we just punt, and run all PPP interfaces
+ * in cooked mode, if we can; otherwise, we just treat
+ * it as DLT_RAW, for now - if somebody needs to capture,
+ * on a 2.0[.x] kernel, on PPP devices that supply a
+ * link-layer header, they'll have to add code here to
+ * map to the appropriate DLT_ type (possibly adding a
+ * new DLT_ type, if necessary).
+ */
+ if (cooked_ok)
+ handle->linktype = DLT_LINUX_SLL;
+ else {
+ /*
+ * XXX - handle ISDN types here? We can't fall
+ * back on cooked sockets, so we'd have to
+ * figure out from the device name what type of
+ * link-layer encapsulation it's using, and map
+ * that to an appropriate DLT_ value, meaning
+ * we'd map "isdnN" devices to DLT_RAW (they
+ * supply raw IP packets with no link-layer
+ * header) and "isdY" devices to a new DLT_I4L_IP
+ * type that has only an Ethernet packet type as
+ * a link-layer header.
+ *
+ * But sometimes we seem to get random crap
+ * in the link-layer header when capturing on
+ * ISDN devices....
+ */
+ handle->linktype = DLT_RAW;
+ }
+ break;
+
+#ifndef ARPHRD_CISCO
+#define ARPHRD_CISCO 513 /* previously ARPHRD_HDLC */
+#endif
+ case ARPHRD_CISCO:
+ handle->linktype = DLT_C_HDLC;
+ break;
+
+ /* Not sure if this is correct for all tunnels, but it
+ * works for CIPE */
+ case ARPHRD_TUNNEL:
+#ifndef ARPHRD_SIT
+#define ARPHRD_SIT 776 /* From Linux 2.2.13 */
+#endif
+ case ARPHRD_SIT:
+ case ARPHRD_CSLIP:
+ case ARPHRD_SLIP6:
+ case ARPHRD_CSLIP6:
+ case ARPHRD_ADAPT:
+ case ARPHRD_SLIP:
+#ifndef ARPHRD_RAWHDLC
+#define ARPHRD_RAWHDLC 518
+#endif
+ case ARPHRD_RAWHDLC:
+#ifndef ARPHRD_DLCI
+#define ARPHRD_DLCI 15
+#endif
+ case ARPHRD_DLCI:
+ /*
+ * XXX - should some of those be mapped to DLT_LINUX_SLL
+ * instead? Should we just map all of them to DLT_LINUX_SLL?
+ */
+ handle->linktype = DLT_RAW;
+ break;
+
+#ifndef ARPHRD_FRAD
+#define ARPHRD_FRAD 770
+#endif
+ case ARPHRD_FRAD:
+ handle->linktype = DLT_FRELAY;
+ break;
+
+ case ARPHRD_LOCALTLK:
+ handle->linktype = DLT_LTALK;
+ break;
+
+#ifndef ARPHRD_FCPP
+#define ARPHRD_FCPP 784
+#endif
+ case ARPHRD_FCPP:
+#ifndef ARPHRD_FCAL
+#define ARPHRD_FCAL 785
+#endif
+ case ARPHRD_FCAL:
+#ifndef ARPHRD_FCPL
+#define ARPHRD_FCPL 786
+#endif
+ case ARPHRD_FCPL:
+#ifndef ARPHRD_FCFABRIC
+#define ARPHRD_FCFABRIC 787
+#endif
+ case ARPHRD_FCFABRIC:
+ /*
+ * We assume that those all mean RFC 2625 IP-over-
+ * Fibre Channel, with the RFC 2625 header at
+ * the beginning of the packet.
+ */
+ handle->linktype = DLT_IP_OVER_FC;
+ break;
+
+#ifndef ARPHRD_IRDA
+#define ARPHRD_IRDA 783
+#endif
+ case ARPHRD_IRDA:
+ /* Don't expect IP packet out of this interfaces... */
+ handle->linktype = DLT_LINUX_IRDA;
+ /* We need to save packet direction for IrDA decoding,
+ * so let's use "Linux-cooked" mode. Jean II */
+ //handle->md.cooked = 1;
+ break;
+
+ /* ARPHRD_LAPD is unofficial and randomly allocated, if reallocation
+#ifndef ARPHRD_LAPD
+#define ARPHRD_LAPD 8445
+#endif
+ case ARPHRD_LAPD:
+ /* Don't expect IP packet out of this interfaces... */
+ handle->linktype = DLT_LINUX_LAPD;
+ break;
+
+#ifndef ARPHRD_NONE
+#define ARPHRD_NONE 0xFFFE
+#endif
+ case ARPHRD_NONE:
+ /*
+ * No link-layer header; packets are just IP
+ * packets, so use DLT_RAW.
+ */
+ handle->linktype = DLT_RAW;
+ break;
+
+#ifndef ARPHRD_IEEE802154
+#define ARPHRD_IEEE802154 804
+#endif
+ case ARPHRD_IEEE802154:
+ handle->linktype = DLT_IEEE802_15_4_NOFCS;
+ break;
+
+ default:
+ handle->linktype = -1;
+ break;
+ }
+}
+
+/* ===== Functions to interface to the newer kernels ================== */
+
+/*
+ * Try to open a packet socket using the new kernel PF_PACKET interface.
+ * Returns 1 on success, 0 on an error that means the new interface isn't
+ * present (so the old SOCK_PACKET interface should be tried), and a
+ * PCAP_ERROR_ value on an error that means that the old mechanism won't
+ * work either (so it shouldn't be tried).
+ */
+static int
+activate_new(pcap_t *handle)
+{
+#ifdef HAVE_PF_PACKET_SOCKETS
+ const char *device = handle->opt.source;
+ int is_any_device = (strcmp(device, "any") == 0);
+ int sock_fd = -1, arptype;
+#ifdef HAVE_PACKET_AUXDATA
+ int val;
+#endif
+ int err = 0;
+ struct packet_mreq mr;
+
+ /*
+ * Open a socket with protocol family packet. If the
+ * "any" device was specified, we open a SOCK_DGRAM
+ * socket for the cooked interface, otherwise we first
+ * try a SOCK_RAW socket for the raw interface.
+ */
+ sock_fd = is_any_device ?
+ socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_ALL)) :
+ socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
+
+ if (sock_fd == -1) {
+ if (errno == EINVAL || errno == EAFNOSUPPORT) {
+ /*
+ * We don't support PF_PACKET/SOCK_whatever
+ * sockets; try the old mechanism.
+ */
+ return 0;
+ }
+
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "socket: %s",
+ pcap_strerror(errno) );
+ if (errno == EPERM || errno == EACCES) {
+ /*
+ * You don't have permission to open the
+ * socket.
+ */
+ return PCAP_ERROR_PERM_DENIED;
+ } else {
+ /*
+ * Other error.
+ */
+ return PCAP_ERROR;
+ }
+ }
+
+ /* It seems the kernel supports the new interface. */
+ handle->md.sock_packet = 0;
+
+ /*
+ * Get the interface index of the loopback device.
+ * If the attempt fails, don't fail, just set the
+ * "md.lo_ifindex" to -1.
+ *
+ * XXX - can there be more than one device that loops
+ * packets back, i.e. devices other than "lo"? If so,
+ * we'd need to find them all, and have an array of
+ * indices for them, and check all of them in
+ * "pcap_read_packet()".
+ */
+ handle->md.lo_ifindex = iface_get_id(sock_fd, "lo", handle->errbuf);
+
+ /*
+ * Default value for offset to align link-layer payload
+ * on a 4-byte boundary.
+ */
+ handle->offset = 0;
+
+ /*
+ * What kind of frames do we have to deal with? Fall back
+ * to cooked mode if we have an unknown interface type
+ * or a type we know doesn't work well in raw mode.
+ */
+ if (!is_any_device) {
+ /* Assume for now we don't need cooked mode. */
+ handle->md.cooked = 0;
+
+ if (handle->opt.rfmon) {
+ /*
+ * We were asked to turn on monitor mode.
+ * Do so before we get the link-layer type,
+ * because entering monitor mode could change
+ * the link-layer type.
+ */
+ err = enter_rfmon_mode(handle, sock_fd, device);
+ if (err < 0) {
+ /* Hard failure */
+ close(sock_fd);
+ return err;
+ }
+ if (err == 0) {
+ /*
+ * Nothing worked for turning monitor mode
+ * on.
+ */
+ close(sock_fd);
+ return PCAP_ERROR_RFMON_NOTSUP;
+ }
+
+ /*
+ * Either monitor mode has been turned on for
+ * the device, or we've been given a different
+ * device to open for monitor mode. If we've
+ * been given a different device, use it.
+ */
+ if (handle->md.mondevice != NULL)
+ device = handle->md.mondevice;
+ }
+ arptype = iface_get_arptype(sock_fd, device, handle->errbuf);
+ if (arptype < 0) {
+ close(sock_fd);
+ return arptype;
+ }
+ map_arphrd_to_dlt(handle, sock_fd, arptype, device, 1);
+ if (handle->linktype == -1 ||
+ handle->linktype == DLT_LINUX_SLL ||
+ handle->linktype == DLT_LINUX_IRDA ||
+ handle->linktype == DLT_LINUX_LAPD ||
+ (handle->linktype == DLT_EN10MB &&
+ (strncmp("isdn", device, 4) == 0 ||
+ strncmp("isdY", device, 4) == 0))) {
+ /*
+ * Unknown interface type (-1), or a
+ * device we explicitly chose to run
+ * in cooked mode (e.g., PPP devices),
+ * or an ISDN device (whose link-layer
+ * type we can only determine by using
+ * APIs that may be different on different
+ * kernels) - reopen in cooked mode.
+ */
+ if (close(sock_fd) == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "close: %s", pcap_strerror(errno));
+ return PCAP_ERROR;
+ }
+ sock_fd = socket(PF_PACKET, SOCK_DGRAM,
+ htons(ETH_P_ALL));
+ if (sock_fd == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "socket: %s", pcap_strerror(errno));
+ if (errno == EPERM || errno == EACCES) {
+ /*
+ * You don't have permission to
+ * open the socket.
+ */
+ return PCAP_ERROR_PERM_DENIED;
+ } else {
+ /*
+ * Other error.
+ */
+ return PCAP_ERROR;
+ }
+ }
+ handle->md.cooked = 1;
+
+ /*
+ * Get rid of any link-layer type list
+ * we allocated - this only supports cooked
+ * capture.
+ */
+ if (handle->dlt_list != NULL) {
+ free(handle->dlt_list);
+ handle->dlt_list = NULL;
+ handle->dlt_count = 0;
+ }
+
+ if (handle->linktype == -1) {
+ /*
+ * Warn that we're falling back on
+ * cooked mode; we may want to
+ * update "map_arphrd_to_dlt()"
+ * to handle the new type.
+ */
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "arptype %d not "
+ "supported by libpcap - "
+ "falling back to cooked "
+ "socket",
+ arptype);
+ }
+
+ /*
+ * IrDA capture is not a real "cooked" capture,
+ * it's IrLAP frames, not IP packets. The
+ * same applies to LAPD capture.
+ */
+ if (handle->linktype != DLT_LINUX_IRDA &&
+ handle->linktype != DLT_LINUX_LAPD)
+ handle->linktype = DLT_LINUX_SLL;
+ }
+
+ handle->md.ifindex = iface_get_id(sock_fd, device,
+ handle->errbuf);
+ if (handle->md.ifindex == -1) {
+ close(sock_fd);
+ return PCAP_ERROR;
+ }
+
+ if ((err = iface_bind(sock_fd, handle->md.ifindex,
+ handle->errbuf)) != 1) {
+ close(sock_fd);
+ if (err < 0)
+ return err;
+ else
+ return 0; /* try old mechanism */
+ }
+ } else {
+ /*
+ * The "any" device.
+ */
+ if (handle->opt.rfmon) {
+ /*
+ * It doesn't support monitor mode.
+ */
+ return PCAP_ERROR_RFMON_NOTSUP;
+ }
+
+ /*
+ * It uses cooked mode.
+ */
+ handle->md.cooked = 1;
+ handle->linktype = DLT_LINUX_SLL;
+
+ /*
+ * We're not bound to a device.
+ * For now, we're using this as an indication
+ * that we can't transmit; stop doing that only
+ * if we figure out how to transmit in cooked
+ * mode.
+ */
+ handle->md.ifindex = -1;
+ }
+
+ /*
+ * Select promiscuous mode on if "promisc" is set.
+ *
+ * Do not turn allmulti mode on if we don't select
+ * promiscuous mode - on some devices (e.g., Orinoco
+ * wireless interfaces), allmulti mode isn't supported
+ * and the driver implements it by turning promiscuous
+ * mode on, and that screws up the operation of the
+ * card as a normal networking interface, and on no
+ * other platform I know of does starting a non-
+ * promiscuous capture affect which multicast packets
+ * are received by the interface.
+ */
+
+ /*
+ * Hmm, how can we set promiscuous mode on all interfaces?
+ * I am not sure if that is possible at all. For now, we
+ * silently ignore attempts to turn promiscuous mode on
+ * for the "any" device (so you don't have to explicitly
+ * disable it in programs such as tcpdump).
+ */
+
+ if (!is_any_device && handle->opt.promisc) {
+ memset(&mr, 0, sizeof(mr));
+ mr.mr_ifindex = handle->md.ifindex;
+ mr.mr_type = PACKET_MR_PROMISC;
+ if (setsockopt(sock_fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP,
+ &mr, sizeof(mr)) == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "setsockopt: %s", pcap_strerror(errno));
+ close(sock_fd);
+ return PCAP_ERROR;
+ }
+ }
+
+ /* Enable auxillary data if supported and reserve room for
+ * reconstructing VLAN headers. */
+#ifdef HAVE_PACKET_AUXDATA
+ val = 1;
+ if (setsockopt(sock_fd, SOL_PACKET, PACKET_AUXDATA, &val,
+ sizeof(val)) == -1 && errno != ENOPROTOOPT) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "setsockopt: %s", pcap_strerror(errno));
+ close(sock_fd);
+ return PCAP_ERROR;
+ }
+ handle->offset += VLAN_TAG_LEN;
+#endif /* HAVE_PACKET_AUXDATA */
+
+ /*
+ * This is a 2.2[.x] or later kernel (we know that
+ * because we're not using a SOCK_PACKET socket -
+ * PF_PACKET is supported only in 2.2 and later
+ * kernels).
+ *
+ * We can safely pass "recvfrom()" a byte count
+ * based on the snapshot length.
+ *
+ * If we're in cooked mode, make the snapshot length
+ * large enough to hold a "cooked mode" header plus
+ * 1 byte of packet data (so we don't pass a byte
+ * count of 0 to "recvfrom()").
+ */
+ if (handle->md.cooked) {
+ if (handle->snapshot < SLL_HDR_LEN + 1)
+ handle->snapshot = SLL_HDR_LEN + 1;
+ }
+ handle->bufsize = handle->snapshot;
+
+ /*
+ * Set the offset at which to insert VLAN tags.
+ */
+ switch (handle->linktype) {
+
+ case DLT_EN10MB:
+ handle->md.vlan_offset = 2 * ETH_ALEN;
+ break;
-#ifndef ARPHRD_IEEE802_TR
-#define ARPHRD_IEEE802_TR 800 /* From Linux 2.4 */
-#endif
- case ARPHRD_IEEE802_TR:
- case ARPHRD_IEEE802:
- handle->linktype = DLT_IEEE802;
- handle->offset = 2;
+ case DLT_LINUX_SLL:
+ handle->md.vlan_offset = 14;
break;
- case ARPHRD_ARCNET:
- handle->linktype = DLT_ARCNET_LINUX;
+ default:
+ handle->md.vlan_offset = -1; /* unknown */
break;
+ }
-#ifndef ARPHRD_FDDI /* From Linux 2.2.13 */
-#define ARPHRD_FDDI 774
+ /* Save the socket FD in the pcap structure */
+ handle->fd = sock_fd;
+
+ return 1;
+#else
+ strncpy(ebuf,
+ "New packet capturing interface not supported by build "
+ "environment", PCAP_ERRBUF_SIZE);
+ return 0;
#endif
- case ARPHRD_FDDI:
- handle->linktype = DLT_FDDI;
- handle->offset = 3;
+}
+
+#ifdef HAVE_PACKET_RING
+/*
+ * Attempt to activate with memory-mapped access.
+ *
+ * On success, returns 1, and sets *status to 0 if there are no warnings
+ * or to a PCAP_WARNING_ code if there is a warning.
+ *
+ * On failure due to lack of support for memory-mapped capture, returns
+ * 0.
+ *
+ * On error, returns -1, and sets *status to the appropriate error code;
+ * if that is PCAP_ERROR, sets handle->errbuf to the appropriate message.
+ */
+static int
+activate_mmap(pcap_t *handle, int *status)
+{
+ int ret;
+
+ /*
+ * Attempt to allocate a buffer to hold the contents of one
+ * packet, for use by the oneshot callback.
+ */
+ handle->md.oneshot_buffer = malloc(handle->snapshot);
+ if (handle->md.oneshot_buffer == NULL) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "can't allocate oneshot buffer: %s",
+ pcap_strerror(errno));
+ *status = PCAP_ERROR;
+ return -1;
+ }
+
+ if (handle->opt.buffer_size == 0) {
+ /* by default request 2M for the ring buffer */
+ handle->opt.buffer_size = 2*1024*1024;
+ }
+ ret = prepare_tpacket_socket(handle);
+ if (ret == -1) {
+ free(handle->md.oneshot_buffer);
+ *status = PCAP_ERROR;
+ return ret;
+ }
+ ret = create_ring(handle, status);
+ if (ret == 0) {
+ /*
+ * We don't support memory-mapped capture; our caller
+ * will fall back on reading from the socket.
+ */
+ free(handle->md.oneshot_buffer);
+ return 0;
+ }
+ if (ret == -1) {
+ /*
+ * Error attempting to enable memory-mapped capture;
+ * fail. create_ring() has set *status.
+ */
+ free(handle->md.oneshot_buffer);
+ return -1;
+ }
+
+ /*
+ * Success. *status has been set either to 0 if there are no
+ * warnings or to a PCAP_WARNING_ value if there is a warning.
+ *
+ * Override some defaults and inherit the other fields from
+ * activate_new.
+ * handle->offset is used to get the current position into the rx ring.
+ * handle->cc is used to store the ring size.
+ */
+ handle->read_op = pcap_read_linux_mmap;
+ handle->cleanup_op = pcap_cleanup_linux_mmap;
+ handle->setfilter_op = pcap_setfilter_linux_mmap;
+ handle->setnonblock_op = pcap_setnonblock_mmap;
+ handle->getnonblock_op = pcap_getnonblock_mmap;
+ handle->oneshot_callback = pcap_oneshot_mmap;
+ handle->selectable_fd = handle->fd;
+ return 1;
+}
+#else /* HAVE_PACKET_RING */
+static int
+activate_mmap(pcap_t *handle _U_, int *status _U_)
+{
+ return 0;
+}
+#endif /* HAVE_PACKET_RING */
+
+#ifdef HAVE_PACKET_RING
+/*
+ * Attempt to set the socket to version 2 of the memory-mapped header.
+ * Return 1 if we succeed or if we fail because version 2 isn't
+ * supported; return -1 on any other error, and set handle->errbuf.
+ */
+static int
+prepare_tpacket_socket(pcap_t *handle)
+{
+#ifdef HAVE_TPACKET2
+ socklen_t len;
+ int val;
+#endif
+
+ handle->md.tp_version = TPACKET_V1;
+ handle->md.tp_hdrlen = sizeof(struct tpacket_hdr);
+
+#ifdef HAVE_TPACKET2
+ /* Probe whether kernel supports TPACKET_V2 */
+ val = TPACKET_V2;
+ len = sizeof(val);
+ if (getsockopt(handle->fd, SOL_PACKET, PACKET_HDRLEN, &val, &len) < 0) {
+ if (errno == ENOPROTOOPT)
+ return 1; /* no - just drive on */
+
+ /* Yes - treat as a failure. */
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "can't get TPACKET_V2 header len on packet socket: %s",
+ pcap_strerror(errno));
+ return -1;
+ }
+ handle->md.tp_hdrlen = val;
+
+ val = TPACKET_V2;
+ if (setsockopt(handle->fd, SOL_PACKET, PACKET_VERSION, &val,
+ sizeof(val)) < 0) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "can't activate TPACKET_V2 on packet socket: %s",
+ pcap_strerror(errno));
+ return -1;
+ }
+ handle->md.tp_version = TPACKET_V2;
+
+ /* Reserve space for VLAN tag reconstruction */
+ val = VLAN_TAG_LEN;
+ if (setsockopt(handle->fd, SOL_PACKET, PACKET_RESERVE, &val,
+ sizeof(val)) < 0) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "can't set up reserve on packet socket: %s",
+ pcap_strerror(errno));
+ return -1;
+ }
+
+#endif /* HAVE_TPACKET2 */
+ return 1;
+}
+
+/*
+ * Attempt to set up memory-mapped access.
+ *
+ * On success, returns 1, and sets *status to 0 if there are no warnings
+ * or to a PCAP_WARNING_ code if there is a warning.
+ *
+ * On failure due to lack of support for memory-mapped capture, returns
+ * 0.
+ *
+ * On error, returns -1, and sets *status to the appropriate error code;
+ * if that is PCAP_ERROR, sets handle->errbuf to the appropriate message.
+ */
+static int
+create_ring(pcap_t *handle, int *status)
+{
+ unsigned i, j, frames_per_block;
+ struct tpacket_req req;
+ socklen_t len;
+ unsigned int sk_type, tp_reserve, maclen, tp_hdrlen, netoff, macoff;
+ unsigned int frame_size;
+
+ /*
+ * Start out assuming no warnings or errors.
+ */
+ *status = 0;
+
+ /* Note that with large snapshot length (say 64K, which is the default
+ * for recent versions of tcpdump, the value that "-s 0" has given
+ * for a long time with tcpdump, and the default in Wireshark/TShark),
+ * if we use the snapshot length to calculate the frame length,
+ * only a few frames will be available in the ring even with pretty
+ * large ring size (and a lot of memory will be unused).
+ *
+ * Ideally, we should choose a frame length based on the
+ * minimum of the specified snapshot length and the maximum
+ * packet size. That's not as easy as it sounds; consider, for
+ * example, an 802.11 interface in monitor mode, where the
+ * frame would include a radiotap header, where the maximum
+ * radiotap header length is device-dependent.
+ *
+ * So, for now, we just do this for Ethernet devices, where
+ * there's no metadata header, and the link-layer header is
+ * fixed length. We can get the maximum packet size by
+ * adding 18, the Ethernet header length plus the CRC length
+ * (just in case we happen to get the CRC in the packet), to
+ * the MTU of the interface; we fetch the MTU in the hopes
+ * that it reflects support for jumbo frames. (Even if the
+ * interface is just being used for passive snooping, the driver
+ * might set the size of buffers in the receive ring based on
+ * the MTU, so that the MTU limits the maximum size of packets
+ * that we can receive.)
+ *
+ * We don't do that if segmentation/fragmentation or receive
+ * offload are enabled, so we don't get rudely surprised by
+ * "packets" bigger than the MTU. */
+ frame_size = handle->snapshot;
+ if (handle->linktype == DLT_EN10MB) {
+ int mtu;
+ int offload;
+
+ offload = iface_get_offload(handle);
+ if (offload == -1) {
+ *status = PCAP_ERROR;
+ return -1;
+ }
+ if (!offload) {
+ mtu = iface_get_mtu(handle->fd, handle->opt.source,
+ handle->errbuf);
+ if (mtu == -1) {
+ *status = PCAP_ERROR;
+ return -1;
+ }
+ if (frame_size > mtu + 18)
+ frame_size = mtu + 18;
+ }
+ }
+
+ /* NOTE: calculus matching those in tpacket_rcv()
+ * in linux-2.6/net/packet/af_packet.c
+ */
+ len = sizeof(sk_type);
+ if (getsockopt(handle->fd, SOL_SOCKET, SO_TYPE, &sk_type, &len) < 0) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "getsockopt: %s", pcap_strerror(errno));
+ *status = PCAP_ERROR;
+ return -1;
+ }
+#ifdef PACKET_RESERVE
+ len = sizeof(tp_reserve);
+ if (getsockopt(handle->fd, SOL_PACKET, PACKET_RESERVE, &tp_reserve, &len) < 0) {
+ if (errno != ENOPROTOOPT) {
+ /*
+ * ENOPROTOOPT means "kernel doesn't support
+ * PACKET_RESERVE", in which case we fall back
+ * as best we can.
+ */
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "getsockopt: %s", pcap_strerror(errno));
+ *status = PCAP_ERROR;
+ return -1;
+ }
+ tp_reserve = 0; /* older kernel, reserve not supported */
+ }
+#else
+ tp_reserve = 0; /* older kernel, reserve not supported */
+#endif
+ maclen = (sk_type == SOCK_DGRAM) ? 0 : MAX_LINKHEADER_SIZE;
+ /* XXX: in the kernel maclen is calculated from
+ * LL_ALLOCATED_SPACE(dev) and vnet_hdr.hdr_len
+ * in: packet_snd() in linux-2.6/net/packet/af_packet.c
+ * then packet_alloc_skb() in linux-2.6/net/packet/af_packet.c
+ * then sock_alloc_send_pskb() in linux-2.6/net/core/sock.c
+ * but I see no way to get those sizes in userspace,
+ * like for instance with an ifreq ioctl();
+ * the best thing I've found so far is MAX_HEADER in the kernel
+ * part of linux-2.6/include/linux/netdevice.h
+ * which goes up to 128+48=176; since pcap-linux.c defines
+ * a MAX_LINKHEADER_SIZE of 256 which is greater than that,
+ * let's use it.. maybe is it even large enough to directly
+ * replace macoff..
+ */
+ tp_hdrlen = TPACKET_ALIGN(handle->md.tp_hdrlen) + sizeof(struct sockaddr_ll) ;
+ netoff = TPACKET_ALIGN(tp_hdrlen + (maclen < 16 ? 16 : maclen)) + tp_reserve;
+ /* NOTE: AFAICS tp_reserve may break the TPACKET_ALIGN of
+ * netoff, which contradicts
+ * linux-2.6/Documentation/networking/packet_mmap.txt
+ * documenting that:
+ * "- Gap, chosen so that packet data (Start+tp_net)
+ * aligns to TPACKET_ALIGNMENT=16"
+ */
+ /* NOTE: in linux-2.6/include/linux/skbuff.h:
+ * "CPUs often take a performance hit
+ * when accessing unaligned memory locations"
+ */
+ macoff = netoff - maclen;
+ req.tp_frame_size = TPACKET_ALIGN(macoff + frame_size);
+ req.tp_frame_nr = handle->opt.buffer_size/req.tp_frame_size;
+
+ /* compute the minumum block size that will handle this frame.
+ * The block has to be page size aligned.
+ * The max block size allowed by the kernel is arch-dependent and
+ * it's not explicitly checked here. */
+ req.tp_block_size = getpagesize();
+ while (req.tp_block_size < req.tp_frame_size)
+ req.tp_block_size <<= 1;
+
+ frames_per_block = req.tp_block_size/req.tp_frame_size;
+
+ /*
+ * PACKET_TIMESTAMP was added after linux/net_tstamp.h was,
+ * so we check for PACKET_TIMESTAMP. We check for
+ * linux/net_tstamp.h just in case a system somehow has
+ * PACKET_TIMESTAMP but not linux/net_tstamp.h; that might
+ * be unnecessary.
+ *
+ * SIOCSHWTSTAMP was introduced in the patch that introduced
+ * linux/net_tstamp.h, so we don't bother checking whether
+ * SIOCSHWTSTAMP is defined (if your Linux system has
+ * linux/net_tstamp.h but doesn't define SIOCSHWTSTAMP, your
+ * Linux system is badly broken).
+ */
+#if defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP)
+ /*
+ * If we were told to do so, ask the kernel and the driver
+ * to use hardware timestamps.
+ *
+ * Hardware timestamps are only supported with mmapped
+ * captures.
+ */
+ if (handle->opt.tstamp_type == PCAP_TSTAMP_ADAPTER ||
+ handle->opt.tstamp_type == PCAP_TSTAMP_ADAPTER_UNSYNCED) {
+ struct hwtstamp_config hwconfig;
+ struct ifreq ifr;
+ int timesource;
+
+ /*
+ * Ask for hardware time stamps on all packets,
+ * including transmitted packets.
+ */
+ memset(&hwconfig, 0, sizeof(hwconfig));
+ hwconfig.tx_type = HWTSTAMP_TX_ON;
+ hwconfig.rx_filter = HWTSTAMP_FILTER_ALL;
+
+ memset(&ifr, 0, sizeof(ifr));
+ strcpy(ifr.ifr_name, handle->opt.source);
+ ifr.ifr_data = (void *)&hwconfig;
+
+ if (ioctl(handle->fd, SIOCSHWTSTAMP, &ifr) < 0) {
+ switch (errno) {
+
+ case EPERM:
+ /*
+ * Treat this as an error, as the
+ * user should try to run this
+ * with the appropriate privileges -
+ * and, if they can't, shouldn't
+ * try requesting hardware time stamps.
+ */
+ *status = PCAP_ERROR_PERM_DENIED;
+ return -1;
+
+ case EOPNOTSUPP:
+ /*
+ * Treat this as a warning, as the
+ * only way to fix the warning is to
+ * get an adapter that supports hardware
+ * time stamps. We'll just fall back
+ * on the standard host time stamps.
+ */
+ *status = PCAP_WARNING_TSTAMP_TYPE_NOTSUP;
+ break;
+
+ default:
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "SIOCSHWTSTAMP failed: %s",
+ pcap_strerror(errno));
+ *status = PCAP_ERROR;
+ return -1;
+ }
+ } else {
+ /*
+ * Well, that worked. Now specify the type of
+ * hardware time stamp we want for this
+ * socket.
+ */
+ if (handle->opt.tstamp_type == PCAP_TSTAMP_ADAPTER) {
+ /*
+ * Hardware timestamp, synchronized
+ * with the system clock.
+ */
+ timesource = SOF_TIMESTAMPING_SYS_HARDWARE;
+ } else {
+ /*
+ * PCAP_TSTAMP_ADAPTER_UNSYNCED - hardware
+ * timestamp, not synchronized with the
+ * system clock.
+ */
+ timesource = SOF_TIMESTAMPING_RAW_HARDWARE;
+ }
+ if (setsockopt(handle->fd, SOL_PACKET, PACKET_TIMESTAMP,
+ (void *)×ource, sizeof(timesource))) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "can't set PACKET_TIMESTAMP: %s",
+ pcap_strerror(errno));
+ *status = PCAP_ERROR;
+ return -1;
+ }
+ }
+ }
+#endif /* HAVE_LINUX_NET_TSTAMP_H && PACKET_TIMESTAMP */
+
+ /* ask the kernel to create the ring */
+retry:
+ req.tp_block_nr = req.tp_frame_nr / frames_per_block;
+
+ /* req.tp_frame_nr is requested to match frames_per_block*req.tp_block_nr */
+ req.tp_frame_nr = req.tp_block_nr * frames_per_block;
+
+ if (setsockopt(handle->fd, SOL_PACKET, PACKET_RX_RING,
+ (void *) &req, sizeof(req))) {
+ if ((errno == ENOMEM) && (req.tp_block_nr > 1)) {
+ /*
+ * Memory failure; try to reduce the requested ring
+ * size.
+ *
+ * We used to reduce this by half -- do 5% instead.
+ * That may result in more iterations and a longer
+ * startup, but the user will be much happier with
+ * the resulting buffer size.
+ */
+ if (req.tp_frame_nr < 20)
+ req.tp_frame_nr -= 1;
+ else
+ req.tp_frame_nr -= req.tp_frame_nr/20;
+ goto retry;
+ }
+ if (errno == ENOPROTOOPT) {
+ /*
+ * We don't have ring buffer support in this kernel.
+ */
+ return 0;
+ }
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "can't create rx ring on packet socket: %s",
+ pcap_strerror(errno));
+ *status = PCAP_ERROR;
+ return -1;
+ }
+
+ /* memory map the rx ring */
+ handle->md.mmapbuflen = req.tp_block_nr * req.tp_block_size;
+ handle->md.mmapbuf = mmap(0, handle->md.mmapbuflen,
+ PROT_READ|PROT_WRITE, MAP_SHARED, handle->fd, 0);
+ if (handle->md.mmapbuf == MAP_FAILED) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "can't mmap rx ring: %s", pcap_strerror(errno));
+
+ /* clear the allocated ring on error*/
+ destroy_ring(handle);
+ *status = PCAP_ERROR;
+ return -1;
+ }
+
+ /* allocate a ring for each frame header pointer*/
+ handle->cc = req.tp_frame_nr;
+ handle->buffer = malloc(handle->cc * sizeof(union thdr *));
+ if (!handle->buffer) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "can't allocate ring of frame headers: %s",
+ pcap_strerror(errno));
+
+ destroy_ring(handle);
+ *status = PCAP_ERROR;
+ return -1;
+ }
+
+ /* fill the header ring with proper frame ptr*/
+ handle->offset = 0;
+ for (i=0; i<req.tp_block_nr; ++i) {
+ void *base = &handle->md.mmapbuf[i*req.tp_block_size];
+ for (j=0; j<frames_per_block; ++j, ++handle->offset) {
+ RING_GET_FRAME(handle) = base;
+ base += req.tp_frame_size;
+ }
+ }
+
+ handle->bufsize = req.tp_frame_size;
+ handle->offset = 0;
+ return 1;
+}
+
+/* free all ring related resources*/
+static void
+destroy_ring(pcap_t *handle)
+{
+ /* tell the kernel to destroy the ring*/
+ struct tpacket_req req;
+ memset(&req, 0, sizeof(req));
+ setsockopt(handle->fd, SOL_PACKET, PACKET_RX_RING,
+ (void *) &req, sizeof(req));
+
+ /* if ring is mapped, unmap it*/
+ if (handle->md.mmapbuf) {
+ /* do not test for mmap failure, as we can't recover from any error */
+ munmap(handle->md.mmapbuf, handle->md.mmapbuflen);
+ handle->md.mmapbuf = NULL;
+ }
+}
+
+/*
+ * Special one-shot callback, used for pcap_next() and pcap_next_ex(),
+ * for Linux mmapped capture.
+ *
+ * The problem is that pcap_next() and pcap_next_ex() expect the packet
+ * data handed to the callback to be valid after the callback returns,
+ * but pcap_read_linux_mmap() has to release that packet as soon as
+ * the callback returns (otherwise, the kernel thinks there's still
+ * at least one unprocessed packet available in the ring, so a select()
+ * will immediately return indicating that there's data to process), so,
+ * in the callback, we have to make a copy of the packet.
+ *
+ * Yes, this means that, if the capture is using the ring buffer, using
+ * pcap_next() or pcap_next_ex() requires more copies than using
+ * pcap_loop() or pcap_dispatch(). If that bothers you, don't use
+ * pcap_next() or pcap_next_ex().
+ */
+static void
+pcap_oneshot_mmap(u_char *user, const struct pcap_pkthdr *h,
+ const u_char *bytes)
+{
+ struct oneshot_userdata *sp = (struct oneshot_userdata *)user;
+
+ *sp->hdr = *h;
+ memcpy(sp->pd->md.oneshot_buffer, bytes, h->caplen);
+ *sp->pkt = sp->pd->md.oneshot_buffer;
+}
+
+static void
+pcap_cleanup_linux_mmap( pcap_t *handle )
+{
+ destroy_ring(handle);
+ if (handle->md.oneshot_buffer != NULL) {
+ free(handle->md.oneshot_buffer);
+ handle->md.oneshot_buffer = NULL;
+ }
+ pcap_cleanup_linux(handle);
+}
+
+
+static int
+pcap_getnonblock_mmap(pcap_t *p, char *errbuf)
+{
+ /* use negative value of timeout to indicate non blocking ops */
+ return (p->md.timeout<0);
+}
+
+static int
+pcap_setnonblock_mmap(pcap_t *p, int nonblock, char *errbuf)
+{
+ /* map each value to the corresponding 2's complement, to
+ * preserve the timeout value provided with pcap_set_timeout */
+ if (nonblock) {
+ if (p->md.timeout >= 0) {
+ /*
+ * Timeout is non-negative, so we're not already
+ * in non-blocking mode; set it to the 2's
+ * complement, to make it negative, as an
+ * indication that we're in non-blocking mode.
+ */
+ p->md.timeout = p->md.timeout*-1 - 1;
+ }
+ } else {
+ if (p->md.timeout < 0) {
+ /*
+ * Timeout is negative, so we're not already
+ * in blocking mode; reverse the previous
+ * operation, to make the timeout non-negative
+ * again.
+ */
+ p->md.timeout = (p->md.timeout+1)*-1;
+ }
+ }
+ return 0;
+}
+
+static inline union thdr *
+pcap_get_ring_frame(pcap_t *handle, int status)
+{
+ union thdr h;
+
+ h.raw = RING_GET_FRAME(handle);
+ switch (handle->md.tp_version) {
+ case TPACKET_V1:
+ if (status != (h.h1->tp_status ? TP_STATUS_USER :
+ TP_STATUS_KERNEL))
+ return NULL;
break;
+#ifdef HAVE_TPACKET2
+ case TPACKET_V2:
+ if (status != (h.h2->tp_status ? TP_STATUS_USER :
+ TP_STATUS_KERNEL))
+ return NULL;
+ break;
+#endif
+ }
+ return h.raw;
+}
-#ifndef ARPHRD_ATM /* FIXME: How to #include this? */
-#define ARPHRD_ATM 19
+#ifndef POLLRDHUP
+#define POLLRDHUP 0
#endif
- case ARPHRD_ATM:
- /*
- * The Classical IP implementation in ATM for Linux
- * supports both what RFC 1483 calls "LLC Encapsulation",
- * in which each packet has an LLC header, possibly
- * with a SNAP header as well, prepended to it, and
- * what RFC 1483 calls "VC Based Multiplexing", in which
- * different virtual circuits carry different network
- * layer protocols, and no header is prepended to packets.
- *
- * They both have an ARPHRD_ type of ARPHRD_ATM, so
- * you can't use the ARPHRD_ type to find out whether
- * captured packets will have an LLC header, and,
- * while there's a socket ioctl to *set* the encapsulation
- * type, there's no ioctl to *get* the encapsulation type.
- *
- * This means that
- *
- * programs that dissect Linux Classical IP frames
- * would have to check for an LLC header and,
- * depending on whether they see one or not, dissect
- * the frame as LLC-encapsulated or as raw IP (I
- * don't know whether there's any traffic other than
- * IP that would show up on the socket, or whether
- * there's any support for IPv6 in the Linux
- * Classical IP code);
- *
- * filter expressions would have to compile into
- * code that checks for an LLC header and does
- * the right thing.
- *
- * Both of those are a nuisance - and, at least on systems
- * that support PF_PACKET sockets, we don't have to put
- * up with those nuisances; instead, we can just capture
- * in cooked mode. That's what we'll do, if we can.
- * Otherwise, we'll just fail.
- */
- if (cooked_ok)
- handle->linktype = DLT_LINUX_SLL;
+
+static int
+pcap_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback,
+ u_char *user)
+{
+ int timeout;
+ int pkts = 0;
+ char c;
+
+ /* wait for frames availability.*/
+ if (!pcap_get_ring_frame(handle, TP_STATUS_USER)) {
+ struct pollfd pollinfo;
+ int ret;
+
+ pollinfo.fd = handle->fd;
+ pollinfo.events = POLLIN;
+
+ if (handle->md.timeout == 0)
+ timeout = -1; /* block forever */
+ else if (handle->md.timeout > 0)
+ timeout = handle->md.timeout; /* block for that amount of time */
else
- handle->linktype = -1;
- break;
+ timeout = 0; /* non-blocking mode - poll to pick up errors */
+ do {
+ ret = poll(&pollinfo, 1, timeout);
+ if (ret < 0 && errno != EINTR) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "can't poll on packet socket: %s",
+ pcap_strerror(errno));
+ return PCAP_ERROR;
+ } else if (ret > 0 &&
+ (pollinfo.revents & (POLLHUP|POLLRDHUP|POLLERR|POLLNVAL))) {
+ /*
+ * There's some indication other than
+ * "you can read on this descriptor" on
+ * the descriptor.
+ */
+ if (pollinfo.revents & (POLLHUP | POLLRDHUP)) {
+ snprintf(handle->errbuf,
+ PCAP_ERRBUF_SIZE,
+ "Hangup on packet socket");
+ return PCAP_ERROR;
+ }
+ if (pollinfo.revents & POLLERR) {
+ /*
+ * A recv() will give us the
+ * actual error code.
+ *
+ * XXX - make the socket non-blocking?
+ */
+ if (recv(handle->fd, &c, sizeof c,
+ MSG_PEEK) != -1)
+ continue; /* what, no error? */
+ if (errno == ENETDOWN) {
+ /*
+ * The device on which we're
+ * capturing went away.
+ *
+ * XXX - we should really return
+ * PCAP_ERROR_IFACE_NOT_UP,
+ * but pcap_dispatch() etc.
+ * aren't defined to return
+ * that.
+ */
+ snprintf(handle->errbuf,
+ PCAP_ERRBUF_SIZE,
+ "The interface went down");
+ } else {
+ snprintf(handle->errbuf,
+ PCAP_ERRBUF_SIZE,
+ "Error condition on packet socket: %s",
+ strerror(errno));
+ }
+ return PCAP_ERROR;
+ }
+ if (pollinfo.revents & POLLNVAL) {
+ snprintf(handle->errbuf,
+ PCAP_ERRBUF_SIZE,
+ "Invalid polling request on packet socket");
+ return PCAP_ERROR;
+ }
+ }
+ /* check for break loop condition on interrupted syscall*/
+ if (handle->break_loop) {
+ handle->break_loop = 0;
+ return PCAP_ERROR_BREAK;
+ }
+ } while (ret < 0);
+ }
-#ifndef ARPHRD_IEEE80211 /* From Linux 2.4.6 */
-#define ARPHRD_IEEE80211 801
-#endif
- case ARPHRD_IEEE80211:
- handle->linktype = DLT_IEEE802_11;
- break;
+ /* non-positive values of max_packets are used to require all
+ * packets currently available in the ring */
+ while ((pkts < max_packets) || (max_packets <= 0)) {
+ int run_bpf;
+ struct sockaddr_ll *sll;
+ struct pcap_pkthdr pcaphdr;
+ unsigned char *bp;
+ union thdr h;
+ unsigned int tp_len;
+ unsigned int tp_mac;
+ unsigned int tp_snaplen;
+ unsigned int tp_sec;
+ unsigned int tp_usec;
+
+ h.raw = pcap_get_ring_frame(handle, TP_STATUS_USER);
+ if (!h.raw)
+ break;
-#ifndef ARPHRD_IEEE80211_PRISM /* From Linux 2.4.18 */
-#define ARPHRD_IEEE80211_PRISM 802
+ switch (handle->md.tp_version) {
+ case TPACKET_V1:
+ tp_len = h.h1->tp_len;
+ tp_mac = h.h1->tp_mac;
+ tp_snaplen = h.h1->tp_snaplen;
+ tp_sec = h.h1->tp_sec;
+ tp_usec = h.h1->tp_usec;
+ break;
+#ifdef HAVE_TPACKET2
+ case TPACKET_V2:
+ tp_len = h.h2->tp_len;
+ tp_mac = h.h2->tp_mac;
+ tp_snaplen = h.h2->tp_snaplen;
+ tp_sec = h.h2->tp_sec;
+ tp_usec = h.h2->tp_nsec / 1000;
+ break;
#endif
- case ARPHRD_IEEE80211_PRISM:
- handle->linktype = DLT_PRISM_HEADER;
- break;
+ default:
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "unsupported tpacket version %d",
+ handle->md.tp_version);
+ return -1;
+ }
+ /* perform sanity check on internal offset. */
+ if (tp_mac + tp_snaplen > handle->bufsize) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "corrupted frame on kernel ring mac "
+ "offset %u + caplen %u > frame len %d",
+ tp_mac, tp_snaplen, handle->bufsize);
+ return -1;
+ }
+
+ /* run filter on received packet
+ * If the kernel filtering is enabled we need to run the
+ * filter until all the frames present into the ring
+ * at filter creation time are processed.
+ * In such case md.use_bpf is used as a counter for the
+ * packet we need to filter.
+ * Note: alternatively it could be possible to stop applying
+ * the filter when the ring became empty, but it can possibly
+ * happen a lot later... */
+ bp = (unsigned char*)h.raw + tp_mac;
+ run_bpf = (!handle->md.use_bpf) ||
+ ((handle->md.use_bpf>1) && handle->md.use_bpf--);
+ if (run_bpf && handle->fcode.bf_insns &&
+ (bpf_filter(handle->fcode.bf_insns, bp,
+ tp_len, tp_snaplen) == 0))
+ goto skip;
- case ARPHRD_PPP:
/*
- * Some PPP code in the kernel supplies no link-layer
- * header whatsoever to PF_PACKET sockets; other PPP
- * code supplies PPP link-layer headers ("syncppp.c");
- * some PPP code might supply random link-layer
- * headers (PPP over ISDN - there's code in Ethereal,
- * for example, to cope with PPP-over-ISDN captures
- * with which the Ethereal developers have had to cope,
- * heuristically trying to determine which of the
- * oddball link-layer headers particular packets have).
- *
- * As such, we just punt, and run all PPP interfaces
- * in cooked mode, if we can; otherwise, we just treat
- * it as DLT_RAW, for now - if somebody needs to capture,
- * on a 2.0[.x] kernel, on PPP devices that supply a
- * link-layer header, they'll have to add code here to
- * map to the appropriate DLT_ type (possibly adding a
- * new DLT_ type, if necessary).
+ * Do checks based on packet direction.
*/
- if (cooked_ok)
- handle->linktype = DLT_LINUX_SLL;
- else {
+ sll = (void *)h.raw + TPACKET_ALIGN(handle->md.tp_hdrlen);
+ if (sll->sll_pkttype == PACKET_OUTGOING) {
/*
- * XXX - handle ISDN types here? We can't fall
- * back on cooked sockets, so we'd have to
- * figure out from the device name what type of
- * link-layer encapsulation it's using, and map
- * that to an appropriate DLT_ value, meaning
- * we'd map "isdnN" devices to DLT_RAW (they
- * supply raw IP packets with no link-layer
- * header) and "isdY" devices to a new DLT_I4L_IP
- * type that has only an Ethernet packet type as
- * a link-layer header.
- *
- * But sometimes we seem to get random crap
- * in the link-layer header when capturing on
- * ISDN devices....
+ * Outgoing packet.
+ * If this is from the loopback device, reject it;
+ * we'll see the packet as an incoming packet as well,
+ * and we don't want to see it twice.
*/
- handle->linktype = DLT_RAW;
+ if (sll->sll_ifindex == handle->md.lo_ifindex)
+ goto skip;
+
+ /*
+ * If the user only wants incoming packets, reject it.
+ */
+ if (handle->direction == PCAP_D_IN)
+ goto skip;
+ } else {
+ /*
+ * Incoming packet.
+ * If the user only wants outgoing packets, reject it.
+ */
+ if (handle->direction == PCAP_D_OUT)
+ goto skip;
}
- break;
-#ifndef ARPHRD_HDLC
-#define ARPHRD_HDLC 513 /* From Linux 2.2.13 */
-#endif
- case ARPHRD_HDLC:
- handle->linktype = DLT_C_HDLC;
- break;
+ /* get required packet info from ring header */
+ pcaphdr.ts.tv_sec = tp_sec;
+ pcaphdr.ts.tv_usec = tp_usec;
+ pcaphdr.caplen = tp_snaplen;
+ pcaphdr.len = tp_len;
- /* Not sure if this is correct for all tunnels, but it
- * works for CIPE */
- case ARPHRD_TUNNEL:
-#ifndef ARPHRD_SIT
-#define ARPHRD_SIT 776 /* From Linux 2.2.13 */
+ /* if required build in place the sll header*/
+ if (handle->md.cooked) {
+ struct sll_header *hdrp;
+
+ /*
+ * The kernel should have left us with enough
+ * space for an sll header; back up the packet
+ * data pointer into that space, as that'll be
+ * the beginning of the packet we pass to the
+ * callback.
+ */
+ bp -= SLL_HDR_LEN;
+
+ /*
+ * Let's make sure that's past the end of
+ * the tpacket header, i.e. >=
+ * ((u_char *)thdr + TPACKET_HDRLEN), so we
+ * don't step on the header when we construct
+ * the sll header.
+ */
+ if (bp < (u_char *)h.raw +
+ TPACKET_ALIGN(handle->md.tp_hdrlen) +
+ sizeof(struct sockaddr_ll)) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "cooked-mode frame doesn't have room for sll header");
+ return -1;
+ }
+
+ /*
+ * OK, that worked; construct the sll header.
+ */
+ hdrp = (struct sll_header *)bp;
+ hdrp->sll_pkttype = map_packet_type_to_sll_type(
+ sll->sll_pkttype);
+ hdrp->sll_hatype = htons(sll->sll_hatype);
+ hdrp->sll_halen = htons(sll->sll_halen);
+ memcpy(hdrp->sll_addr, sll->sll_addr, SLL_ADDRLEN);
+ hdrp->sll_protocol = sll->sll_protocol;
+
+ /* update packet len */
+ pcaphdr.caplen += SLL_HDR_LEN;
+ pcaphdr.len += SLL_HDR_LEN;
+ }
+
+#ifdef HAVE_TPACKET2
+ if ((handle->md.tp_version == TPACKET_V2) &&
+#if defined(TP_STATUS_VLAN_VALID)
+ (h.h2->tp_vlan_tci || (h.h2->tp_status & TP_STATUS_VLAN_VALID)) &&
+#else
+ h.h2->tp_vlan_tci &&
#endif
- case ARPHRD_SIT:
- case ARPHRD_CSLIP:
- case ARPHRD_SLIP6:
- case ARPHRD_CSLIP6:
- case ARPHRD_ADAPT:
- case ARPHRD_SLIP:
-#ifndef ARPHRD_RAWHDLC
-#define ARPHRD_RAWHDLC 518
+ handle->md.vlan_offset != -1 &&
+ tp_snaplen >= (unsigned int) handle->md.vlan_offset) {
+ struct vlan_tag *tag;
+
+ bp -= VLAN_TAG_LEN;
+ memmove(bp, bp + VLAN_TAG_LEN, handle->md.vlan_offset);
+
+ tag = (struct vlan_tag *)(bp + handle->md.vlan_offset);
+ tag->vlan_tpid = htons(ETH_P_8021Q);
+ tag->vlan_tci = htons(h.h2->tp_vlan_tci);
+
+ pcaphdr.caplen += VLAN_TAG_LEN;
+ pcaphdr.len += VLAN_TAG_LEN;
+ }
#endif
- case ARPHRD_RAWHDLC:
+
/*
- * XXX - should some of those be mapped to DLT_LINUX_SLL
- * instead? Should we just map all of them to DLT_LINUX_SLL?
+ * The only way to tell the kernel to cut off the
+ * packet at a snapshot length is with a filter program;
+ * if there's no filter program, the kernel won't cut
+ * the packet off.
+ *
+ * Trim the snapshot length to be no longer than the
+ * specified snapshot length.
*/
- handle->linktype = DLT_RAW;
- break;
+ if (pcaphdr.caplen > handle->snapshot)
+ pcaphdr.caplen = handle->snapshot;
+
+ /* pass the packet to the user */
+ pkts++;
+ callback(user, &pcaphdr, bp);
+ handle->md.packets_read++;
+
+skip:
+ /* next packet */
+ switch (handle->md.tp_version) {
+ case TPACKET_V1:
+ h.h1->tp_status = TP_STATUS_KERNEL;
+ break;
+#ifdef HAVE_TPACKET2
+ case TPACKET_V2:
+ h.h2->tp_status = TP_STATUS_KERNEL;
+ break;
+#endif
+ }
+ if (++handle->offset >= handle->cc)
+ handle->offset = 0;
- case ARPHRD_LOCALTLK:
- handle->linktype = DLT_LTALK;
- break;
+ /* check for break loop condition*/
+ if (handle->break_loop) {
+ handle->break_loop = 0;
+ return PCAP_ERROR_BREAK;
+ }
+ }
+ return pkts;
+}
-#ifndef ARPHRD_FCPP
-#define ARPHRD_FCPP 784
-#endif
- case ARPHRD_FCPP:
-#ifndef ARPHRD_FCAL
-#define ARPHRD_FCAL 785
-#endif
- case ARPHRD_FCAL:
-#ifndef ARPHRD_FCPL
-#define ARPHRD_FCPL 786
-#endif
- case ARPHRD_FCPL:
-#ifndef ARPHRD_FCFABRIC
-#define ARPHRD_FCFABRIC 787
-#endif
- case ARPHRD_FCFABRIC:
+static int
+pcap_setfilter_linux_mmap(pcap_t *handle, struct bpf_program *filter)
+{
+ int n, offset;
+ int ret;
+
+ /*
+ * Don't rewrite "ret" instructions; we don't need to, as
+ * we're not reading packets with recvmsg(), and we don't
+ * want to, as, by not rewriting them, the kernel can avoid
+ * copying extra data.
+ */
+ ret = pcap_setfilter_linux_common(handle, filter, 1);
+ if (ret < 0)
+ return ret;
+
+ /* if the kernel filter is enabled, we need to apply the filter on
+ * all packets present into the ring. Get an upper bound of their number
+ */
+ if (!handle->md.use_bpf)
+ return ret;
+
+ /* walk the ring backward and count the free slot */
+ offset = handle->offset;
+ if (--handle->offset < 0)
+ handle->offset = handle->cc - 1;
+ for (n=0; n < handle->cc; ++n) {
+ if (--handle->offset < 0)
+ handle->offset = handle->cc - 1;
+ if (!pcap_get_ring_frame(handle, TP_STATUS_KERNEL))
+ break;
+ }
+
+ /* be careful to not change current ring position */
+ handle->offset = offset;
+
+ /* store the number of packets currently present in the ring */
+ handle->md.use_bpf = 1 + (handle->cc - n);
+ return ret;
+}
+
+#endif /* HAVE_PACKET_RING */
+
+
+#ifdef HAVE_PF_PACKET_SOCKETS
+/*
+ * Return the index of the given device name. Fill ebuf and return
+ * -1 on failure.
+ */
+static int
+iface_get_id(int fd, const char *device, char *ebuf)
+{
+ struct ifreq ifr;
+
+ memset(&ifr, 0, sizeof(ifr));
+ strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
+
+ if (ioctl(fd, SIOCGIFINDEX, &ifr) == -1) {
+ snprintf(ebuf, PCAP_ERRBUF_SIZE,
+ "SIOCGIFINDEX: %s", pcap_strerror(errno));
+ return -1;
+ }
+
+ return ifr.ifr_ifindex;
+}
+
+/*
+ * Bind the socket associated with FD to the given device.
+ * Return 1 on success, 0 if we should try a SOCK_PACKET socket,
+ * or a PCAP_ERROR_ value on a hard error.
+ */
+static int
+iface_bind(int fd, int ifindex, char *ebuf)
+{
+ struct sockaddr_ll sll;
+ int err;
+ socklen_t errlen = sizeof(err);
+
+ memset(&sll, 0, sizeof(sll));
+ sll.sll_family = AF_PACKET;
+ sll.sll_ifindex = ifindex;
+ sll.sll_protocol = htons(ETH_P_ALL);
+
+ if (bind(fd, (struct sockaddr *) &sll, sizeof(sll)) == -1) {
+ if (errno == ENETDOWN) {
+ /*
+ * Return a "network down" indication, so that
+ * the application can report that rather than
+ * saying we had a mysterious failure and
+ * suggest that they report a problem to the
+ * libpcap developers.
+ */
+ return PCAP_ERROR_IFACE_NOT_UP;
+ } else {
+ snprintf(ebuf, PCAP_ERRBUF_SIZE,
+ "bind: %s", pcap_strerror(errno));
+ return PCAP_ERROR;
+ }
+ }
+
+ /* Any pending errors, e.g., network is down? */
+
+ if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &errlen) == -1) {
+ snprintf(ebuf, PCAP_ERRBUF_SIZE,
+ "getsockopt: %s", pcap_strerror(errno));
+ return 0;
+ }
+
+ if (err == ENETDOWN) {
/*
- * We assume that those all mean RFC 2625 IP-over-
- * Fibre Channel, with the RFC 2625 header at
- * the beginning of the packet.
+ * Return a "network down" indication, so that
+ * the application can report that rather than
+ * saying we had a mysterious failure and
+ * suggest that they report a problem to the
+ * libpcap developers.
*/
- handle->linktype = DLT_IP_OVER_FC;
- break;
-
- default:
- handle->linktype = -1;
- break;
+ return PCAP_ERROR_IFACE_NOT_UP;
+ } else if (err > 0) {
+ snprintf(ebuf, PCAP_ERRBUF_SIZE,
+ "bind: %s", pcap_strerror(err));
+ return 0;
}
-}
-/* ===== Functions to interface to the newer kernels ================== */
+ return 1;
+}
+#ifdef IW_MODE_MONITOR
/*
- * Try to open a packet socket using the new kernel interface.
- * Returns 0 on failure.
- * FIXME: 0 uses to mean success (Sebastian)
+ * Check whether the device supports the Wireless Extensions.
+ * Returns 1 if it does, 0 if it doesn't, PCAP_ERROR_NO_SUCH_DEVICE
+ * if the device doesn't even exist.
*/
static int
-live_open_new(pcap_t *handle, const char *device, int promisc,
- int to_ms, char *ebuf)
+has_wext(int sock_fd, const char *device, char *ebuf)
{
-#ifdef HAVE_PF_PACKET_SOCKETS
- int sock_fd = -1, device_id, arptype;
- int err;
- int fatal_err = 0;
- struct packet_mreq mr;
-
- /* One shot loop used for error handling - bail out with break */
+ struct iwreq ireq;
+
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ if (ioctl(sock_fd, SIOCGIWNAME, &ireq) >= 0)
+ return 1; /* yes */
+ snprintf(ebuf, PCAP_ERRBUF_SIZE,
+ "%s: SIOCGIWPRIV: %s", device, pcap_strerror(errno));
+ if (errno == ENODEV)
+ return PCAP_ERROR_NO_SUCH_DEVICE;
+ return 0;
+}
- do {
- /*
- * Open a socket with protocol family packet. If a device is
- * given we try to open it in raw mode otherwise we use
- * the cooked interface.
- */
- sock_fd = device ?
- socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL))
- : socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_ALL));
+/*
+ * Per me si va ne la citta dolente,
+ * Per me si va ne l'etterno dolore,
+ * ...
+ * Lasciate ogne speranza, voi ch'intrate.
+ *
+ * XXX - airmon-ng does special stuff with the Orinoco driver and the
+ * wlan-ng driver.
+ */
+typedef enum {
+ MONITOR_WEXT,
+ MONITOR_HOSTAP,
+ MONITOR_PRISM,
+ MONITOR_PRISM54,
+ MONITOR_ACX100,
+ MONITOR_RT2500,
+ MONITOR_RT2570,
+ MONITOR_RT73,
+ MONITOR_RTL8XXX
+} monitor_type;
- if (sock_fd == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE, "socket: %s",
- pcap_strerror(errno) );
- break;
- }
+/*
+ * Use the Wireless Extensions, if we have them, to try to turn monitor mode
+ * on if it's not already on.
+ *
+ * Returns 1 on success, 0 if we don't support the Wireless Extensions
+ * on this device, or a PCAP_ERROR_ value if we do support them but
+ * we weren't able to turn monitor mode on.
+ */
+static int
+enter_rfmon_mode_wext(pcap_t *handle, int sock_fd, const char *device)
+{
+ /*
+ * XXX - at least some adapters require non-Wireless Extensions
+ * mechanisms to turn monitor mode on.
+ *
+ * Atheros cards might require that a separate "monitor virtual access
+ * point" be created, with later versions of the madwifi driver.
+ * airmon-ng does "wlanconfig ath create wlandev {if} wlanmode
+ * monitor -bssid", which apparently spits out a line "athN"
+ * where "athN" is the monitor mode device. To leave monitor
+ * mode, it destroys the monitor mode device.
+ *
+ * Some Intel Centrino adapters might require private ioctls to get
+ * radio headers; the ipw2200 and ipw3945 drivers allow you to
+ * configure a separate "rtapN" interface to capture in monitor
+ * mode without preventing the adapter from operating normally.
+ * (airmon-ng doesn't appear to use that, though.)
+ *
+ * It would be Truly Wonderful if mac80211 and nl80211 cleaned this
+ * up, and if all drivers were converted to mac80211 drivers.
+ *
+ * If interface {if} is a mac80211 driver, the file
+ * /sys/class/net/{if}/phy80211 is a symlink to
+ * /sys/class/ieee80211/{phydev}, for some {phydev}.
+ *
+ * On Fedora 9, with a 2.6.26.3-29 kernel, my Zydas stick, at
+ * least, has a "wmaster0" device and a "wlan0" device; the
+ * latter is the one with the IP address. Both show up in
+ * "tcpdump -D" output. Capturing on the wmaster0 device
+ * captures with 802.11 headers.
+ *
+ * airmon-ng searches through /sys/class/net for devices named
+ * monN, starting with mon0; as soon as one *doesn't* exist,
+ * it chooses that as the monitor device name. If the "iw"
+ * command exists, it does "iw dev {if} interface add {monif}
+ * type monitor", where {monif} is the monitor device. It
+ * then (sigh) sleeps .1 second, and then configures the
+ * device up. Otherwise, if /sys/class/ieee80211/{phydev}/add_iface
+ * is a file, it writes {mondev}, without a newline, to that file,
+ * and again (sigh) sleeps .1 second, and then iwconfig's that
+ * device into monitor mode and configures it up. Otherwise,
+ * you can't do monitor mode.
+ *
+ * All these devices are "glued" together by having the
+ * /sys/class/net/{device}/phy80211 links pointing to the same
+ * place, so, given a wmaster, wlan, or mon device, you can
+ * find the other devices by looking for devices with
+ * the same phy80211 link.
+ *
+ * To turn monitor mode off, delete the monitor interface,
+ * either with "iw dev {monif} interface del" or by sending
+ * {monif}, with no NL, down /sys/class/ieee80211/{phydev}/remove_iface
+ *
+ * Note: if you try to create a monitor device named "monN", and
+ * there's already a "monN" device, it fails, as least with
+ * the netlink interface (which is what iw uses), with a return
+ * value of -ENFILE. (Return values are negative errnos.) We
+ * could probably use that to find an unused device.
+ */
+ int err;
+ struct iwreq ireq;
+ struct iw_priv_args *priv;
+ monitor_type montype;
+ int i;
+ __u32 cmd;
+ struct ifreq ifr;
+ int oldflags;
+ int args[2];
+ int channel;
- /* It seems the kernel supports the new interface. */
- handle->md.sock_packet = 0;
+ /*
+ * Does this device *support* the Wireless Extensions?
+ */
+ err = has_wext(sock_fd, device, handle->errbuf);
+ if (err <= 0)
+ return err; /* either it doesn't or the device doesn't even exist */
+ /*
+ * Start out assuming we have no private extensions to control
+ * radio metadata.
+ */
+ montype = MONITOR_WEXT;
+ cmd = 0;
+ /*
+ * Try to get all the Wireless Extensions private ioctls
+ * supported by this device.
+ *
+ * First, get the size of the buffer we need, by supplying no
+ * buffer and a length of 0. If the device supports private
+ * ioctls, it should return E2BIG, with ireq.u.data.length set
+ * to the length we need. If it doesn't support them, it should
+ * return EOPNOTSUPP.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ ireq.u.data.pointer = (void *)args;
+ ireq.u.data.length = 0;
+ ireq.u.data.flags = 0;
+ if (ioctl(sock_fd, SIOCGIWPRIV, &ireq) != -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: SIOCGIWPRIV with a zero-length buffer didn't fail!",
+ device);
+ return PCAP_ERROR;
+ }
+ if (errno != EOPNOTSUPP) {
/*
- * Get the interface index of the loopback device.
- * If the attempt fails, don't fail, just set the
- * "md.lo_ifindex" to -1.
- *
- * XXX - can there be more than one device that loops
- * packets back, i.e. devices other than "lo"? If so,
- * we'd need to find them all, and have an array of
- * indices for them, and check all of them in
- * "pcap_read_packet()".
+ * OK, it's not as if there are no private ioctls.
*/
- handle->md.lo_ifindex = iface_get_id(sock_fd, "lo", ebuf);
+ if (errno != E2BIG) {
+ /*
+ * Failed.
+ */
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: SIOCGIWPRIV: %s", device,
+ pcap_strerror(errno));
+ return PCAP_ERROR;
+ }
/*
- * Default value for offset to align link-layer payload
- * on a 4-byte boundary.
+ * OK, try to get the list of private ioctls.
*/
- handle->offset = 0;
+ priv = malloc(ireq.u.data.length * sizeof (struct iw_priv_args));
+ if (priv == NULL) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "malloc: %s", pcap_strerror(errno));
+ return PCAP_ERROR;
+ }
+ ireq.u.data.pointer = (void *)priv;
+ if (ioctl(sock_fd, SIOCGIWPRIV, &ireq) == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: SIOCGIWPRIV: %s", device,
+ pcap_strerror(errno));
+ free(priv);
+ return PCAP_ERROR;
+ }
/*
- * What kind of frames do we have to deal with? Fall back
- * to cooked mode if we have an unknown interface type.
+ * Look for private ioctls to turn monitor mode on or, if
+ * monitor mode is on, to set the header type.
*/
-
- if (device) {
- /* Assume for now we don't need cooked mode. */
- handle->md.cooked = 0;
-
- arptype = iface_get_arptype(sock_fd, device, ebuf);
- if (arptype == -1) {
- fatal_err = 1;
+ for (i = 0; i < ireq.u.data.length; i++) {
+ if (strcmp(priv[i].name, "monitor_type") == 0) {
+ /*
+ * Hostap driver, use this one.
+ * Set monitor mode first.
+ * You can set it to 0 to get DLT_IEEE80211,
+ * 1 to get DLT_PRISM, 2 to get
+ * DLT_IEEE80211_RADIO_AVS, and, with more
+ * recent versions of the driver, 3 to get
+ * DLT_IEEE80211_RADIO.
+ */
+ if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
+ break;
+ if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
+ break;
+ if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
+ break;
+ montype = MONITOR_HOSTAP;
+ cmd = priv[i].cmd;
break;
}
- map_arphrd_to_dlt(handle, arptype, 1);
- if (handle->linktype == -1 ||
- handle->linktype == DLT_LINUX_SLL ||
- (handle->linktype == DLT_EN10MB &&
- (strncmp("isdn", device, 4) == 0 ||
- strncmp("isdY", device, 4) == 0))) {
+ if (strcmp(priv[i].name, "set_prismhdr") == 0) {
/*
- * Unknown interface type (-1), or a
- * device we explicitly chose to run
- * in cooked mode (e.g., PPP devices),
- * or an ISDN device (whose link-layer
- * type we can only determine by using
- * APIs that may be different on different
- * kernels) - reopen in cooked mode.
+ * Prism54 driver, use this one.
+ * Set monitor mode first.
+ * You can set it to 2 to get DLT_IEEE80211
+ * or 3 or get DLT_PRISM.
*/
- if (close(sock_fd) == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "close: %s", pcap_strerror(errno));
+ if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
break;
- }
- sock_fd = socket(PF_PACKET, SOCK_DGRAM,
- htons(ETH_P_ALL));
- if (sock_fd == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "socket: %s", pcap_strerror(errno));
+ if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
break;
- }
- handle->md.cooked = 1;
+ if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
+ break;
+ montype = MONITOR_PRISM54;
+ cmd = priv[i].cmd;
+ break;
+ }
+ if (strcmp(priv[i].name, "forceprismheader") == 0) {
+ /*
+ * RT2570 driver, use this one.
+ * Do this after turning monitor mode on.
+ * You can set it to 1 to get DLT_PRISM or 2
+ * to get DLT_IEEE80211.
+ */
+ if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
+ break;
+ if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
+ break;
+ if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
+ break;
+ montype = MONITOR_RT2570;
+ cmd = priv[i].cmd;
+ break;
+ }
+ if (strcmp(priv[i].name, "forceprism") == 0) {
+ /*
+ * RT73 driver, use this one.
+ * Do this after turning monitor mode on.
+ * Its argument is a *string*; you can
+ * set it to "1" to get DLT_PRISM or "2"
+ * to get DLT_IEEE80211.
+ */
+ if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_CHAR)
+ break;
+ if (priv[i].set_args & IW_PRIV_SIZE_FIXED)
+ break;
+ montype = MONITOR_RT73;
+ cmd = priv[i].cmd;
+ break;
+ }
+ if (strcmp(priv[i].name, "prismhdr") == 0) {
+ /*
+ * One of the RTL8xxx drivers, use this one.
+ * It can only be done after monitor mode
+ * has been turned on. You can set it to 1
+ * to get DLT_PRISM or 0 to get DLT_IEEE80211.
+ */
+ if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
+ break;
+ if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
+ break;
+ if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
+ break;
+ montype = MONITOR_RTL8XXX;
+ cmd = priv[i].cmd;
+ break;
+ }
+ if (strcmp(priv[i].name, "rfmontx") == 0) {
+ /*
+ * RT2500 or RT61 driver, use this one.
+ * It has one one-byte parameter; set
+ * u.data.length to 1 and u.data.pointer to
+ * point to the parameter.
+ * It doesn't itself turn monitor mode on.
+ * You can set it to 1 to allow transmitting
+ * in monitor mode(?) and get DLT_IEEE80211,
+ * or set it to 0 to disallow transmitting in
+ * monitor mode(?) and get DLT_PRISM.
+ */
+ if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
+ break;
+ if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 2)
+ break;
+ montype = MONITOR_RT2500;
+ cmd = priv[i].cmd;
+ break;
+ }
+ if (strcmp(priv[i].name, "monitor") == 0) {
+ /*
+ * Either ACX100 or hostap, use this one.
+ * It turns monitor mode on.
+ * If it takes two arguments, it's ACX100;
+ * the first argument is 1 for DLT_PRISM
+ * or 2 for DLT_IEEE80211, and the second
+ * argument is the channel on which to
+ * run. If it takes one argument, it's
+ * HostAP, and the argument is 2 for
+ * DLT_IEEE80211 and 3 for DLT_PRISM.
+ *
+ * If we see this, we don't quit, as this
+ * might be a version of the hostap driver
+ * that also supports "monitor_type".
+ */
+ if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
+ break;
+ if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
+ break;
+ switch (priv[i].set_args & IW_PRIV_SIZE_MASK) {
- if (handle->linktype == -1) {
- /*
- * Warn that we're falling back on
- * cooked mode; we may want to
- * update "map_arphrd_to_dlt()"
- * to handle the new type.
- */
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "arptype %d not "
- "supported by libpcap - "
- "falling back to cooked "
- "socket",
- arptype);
+ case 1:
+ montype = MONITOR_PRISM;
+ cmd = priv[i].cmd;
+ break;
+
+ case 2:
+ montype = MONITOR_ACX100;
+ cmd = priv[i].cmd;
+ break;
+
+ default:
+ break;
}
- handle->linktype = DLT_LINUX_SLL;
}
+ }
+ free(priv);
+ }
- device_id = iface_get_id(sock_fd, device, ebuf);
- if (device_id == -1)
- break;
+ /*
+ * XXX - ipw3945? islism?
+ */
- if ((err = iface_bind(sock_fd, device_id, ebuf)) < 0) {
- if (err == -2)
- fatal_err = 1;
- break;
- }
- } else {
+ /*
+ * Get the old mode.
+ */
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ if (ioctl(sock_fd, SIOCGIWMODE, &ireq) == -1) {
+ /*
+ * We probably won't be able to set the mode, either.
+ */
+ return PCAP_ERROR_RFMON_NOTSUP;
+ }
+
+ /*
+ * Is it currently in monitor mode?
+ */
+ if (ireq.u.mode == IW_MODE_MONITOR) {
+ /*
+ * Yes. Just leave things as they are.
+ * We don't offer multiple link-layer types, as
+ * changing the link-layer type out from under
+ * somebody else capturing in monitor mode would
+ * be considered rude.
+ */
+ return 1;
+ }
+ /*
+ * No. We have to put the adapter into rfmon mode.
+ */
+
+ /*
+ * If we haven't already done so, arrange to have
+ * "pcap_close_all()" called when we exit.
+ */
+ if (!pcap_do_addexit(handle)) {
+ /*
+ * "atexit()" failed; don't put the interface
+ * in rfmon mode, just give up.
+ */
+ return PCAP_ERROR_RFMON_NOTSUP;
+ }
+
+ /*
+ * Save the old mode.
+ */
+ handle->md.oldmode = ireq.u.mode;
+
+ /*
+ * Put the adapter in rfmon mode. How we do this depends
+ * on whether we have a special private ioctl or not.
+ */
+ if (montype == MONITOR_PRISM) {
+ /*
+ * We have the "monitor" private ioctl, but none of
+ * the other private ioctls. Use this, and select
+ * the Prism header.
+ *
+ * If it fails, just fall back on SIOCSIWMODE.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ ireq.u.data.length = 1; /* 1 argument */
+ args[0] = 3; /* request Prism header */
+ memcpy(ireq.u.name, args, IFNAMSIZ);
+ if (ioctl(sock_fd, cmd, &ireq) != -1) {
/*
- * This is cooked mode.
+ * Success.
+ * Note that we have to put the old mode back
+ * when we close the device.
*/
- handle->md.cooked = 1;
- handle->linktype = DLT_LINUX_SLL;
+ handle->md.must_do_on_close |= MUST_CLEAR_RFMON;
/*
- * XXX - squelch GCC complaints about
- * uninitialized variables; if we can't
- * select promiscuous mode on all interfaces,
- * we should move the code below into the
- * "if (device)" branch of the "if" and
- * get rid of the next statement.
+ * Add this to the list of pcaps to close
+ * when we exit.
*/
- device_id = -1;
+ pcap_add_to_pcaps_to_close(handle);
+
+ return 1;
}
/*
- * Select promiscuous mode on if "promisc" is set.
- *
- * Do not turn allmulti mode on if we don't select
- * promiscuous mode - on some devices (e.g., Orinoco
- * wireless interfaces), allmulti mode isn't supported
- * and the driver implements it by turning promiscuous
- * mode on, and that screws up the operation of the
- * card as a normal networking interface, and on no
- * other platform I know of does starting a non-
- * promiscuous capture affect which multicast packets
- * are received by the interface.
+ * Failure. Fall back on SIOCSIWMODE.
+ */
+ }
+
+ /*
+ * First, take the interface down if it's up; otherwise, we
+ * might get EBUSY.
+ */
+ memset(&ifr, 0, sizeof(ifr));
+ strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
+ if (ioctl(sock_fd, SIOCGIFFLAGS, &ifr) == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: Can't get flags: %s", device, strerror(errno));
+ return PCAP_ERROR;
+ }
+ oldflags = 0;
+ if (ifr.ifr_flags & IFF_UP) {
+ oldflags = ifr.ifr_flags;
+ ifr.ifr_flags &= ~IFF_UP;
+ if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: Can't set flags: %s", device, strerror(errno));
+ return PCAP_ERROR;
+ }
+ }
+
+ /*
+ * Then turn monitor mode on.
+ */
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ ireq.u.mode = IW_MODE_MONITOR;
+ if (ioctl(sock_fd, SIOCSIWMODE, &ireq) == -1) {
+ /*
+ * Scientist, you've failed.
+ * Bring the interface back up if we shut it down.
*/
+ ifr.ifr_flags = oldflags;
+ if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: Can't set flags: %s", device, strerror(errno));
+ return PCAP_ERROR;
+ }
+ return PCAP_ERROR_RFMON_NOTSUP;
+ }
+
+ /*
+ * XXX - airmon-ng does "iwconfig {if} key off" after setting
+ * monitor mode and setting the channel, and then does
+ * "iwconfig up".
+ */
+
+ /*
+ * Now select the appropriate radio header.
+ */
+ switch (montype) {
+ case MONITOR_WEXT:
/*
- * Hmm, how can we set promiscuous mode on all interfaces?
- * I am not sure if that is possible at all.
+ * We don't have any private ioctl to set the header.
*/
+ break;
- if (device && promisc) {
- memset(&mr, 0, sizeof(mr));
- mr.mr_ifindex = device_id;
- mr.mr_type = PACKET_MR_PROMISC;
- if (setsockopt(sock_fd, SOL_PACKET,
- PACKET_ADD_MEMBERSHIP, &mr, sizeof(mr)) == -1)
- {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "setsockopt: %s", pcap_strerror(errno));
- break;
+ case MONITOR_HOSTAP:
+ /*
+ * Try to select the radiotap header.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ args[0] = 3; /* request radiotap header */
+ memcpy(ireq.u.name, args, sizeof (int));
+ if (ioctl(sock_fd, cmd, &ireq) != -1)
+ break; /* success */
+
+ /*
+ * That failed. Try to select the AVS header.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ args[0] = 2; /* request AVS header */
+ memcpy(ireq.u.name, args, sizeof (int));
+ if (ioctl(sock_fd, cmd, &ireq) != -1)
+ break; /* success */
+
+ /*
+ * That failed. Try to select the Prism header.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ args[0] = 1; /* request Prism header */
+ memcpy(ireq.u.name, args, sizeof (int));
+ ioctl(sock_fd, cmd, &ireq);
+ break;
+
+ case MONITOR_PRISM:
+ /*
+ * The private ioctl failed.
+ */
+ break;
+
+ case MONITOR_PRISM54:
+ /*
+ * Select the Prism header.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ args[0] = 3; /* request Prism header */
+ memcpy(ireq.u.name, args, sizeof (int));
+ ioctl(sock_fd, cmd, &ireq);
+ break;
+
+ case MONITOR_ACX100:
+ /*
+ * Get the current channel.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ if (ioctl(sock_fd, SIOCGIWFREQ, &ireq) == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: SIOCGIWFREQ: %s", device,
+ pcap_strerror(errno));
+ return PCAP_ERROR;
+ }
+ channel = ireq.u.freq.m;
+
+ /*
+ * Select the Prism header, and set the channel to the
+ * current value.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ args[0] = 1; /* request Prism header */
+ args[1] = channel; /* set channel */
+ memcpy(ireq.u.name, args, 2*sizeof (int));
+ ioctl(sock_fd, cmd, &ireq);
+ break;
+
+ case MONITOR_RT2500:
+ /*
+ * Disallow transmission - that turns on the
+ * Prism header.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ args[0] = 0; /* disallow transmitting */
+ memcpy(ireq.u.name, args, sizeof (int));
+ ioctl(sock_fd, cmd, &ireq);
+ break;
+
+ case MONITOR_RT2570:
+ /*
+ * Force the Prism header.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ args[0] = 1; /* request Prism header */
+ memcpy(ireq.u.name, args, sizeof (int));
+ ioctl(sock_fd, cmd, &ireq);
+ break;
+
+ case MONITOR_RT73:
+ /*
+ * Force the Prism header.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ ireq.u.data.length = 1; /* 1 argument */
+ ireq.u.data.pointer = "1";
+ ireq.u.data.flags = 0;
+ ioctl(sock_fd, cmd, &ireq);
+ break;
+
+ case MONITOR_RTL8XXX:
+ /*
+ * Force the Prism header.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ args[0] = 1; /* request Prism header */
+ memcpy(ireq.u.name, args, sizeof (int));
+ ioctl(sock_fd, cmd, &ireq);
+ break;
+ }
+
+ /*
+ * Now bring the interface back up if we brought it down.
+ */
+ if (oldflags != 0) {
+ ifr.ifr_flags = oldflags;
+ if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: Can't set flags: %s", device, strerror(errno));
+
+ /*
+ * At least try to restore the old mode on the
+ * interface.
+ */
+ if (ioctl(handle->fd, SIOCSIWMODE, &ireq) == -1) {
+ /*
+ * Scientist, you've failed.
+ */
+ fprintf(stderr,
+ "Can't restore interface wireless mode (SIOCSIWMODE failed: %s).\n"
+ "Please adjust manually.\n",
+ strerror(errno));
}
+ return PCAP_ERROR;
}
+ }
- /* Save the socket FD in the pcap structure */
+ /*
+ * Note that we have to put the old mode back when we
+ * close the device.
+ */
+ handle->md.must_do_on_close |= MUST_CLEAR_RFMON;
- handle->fd = sock_fd;
+ /*
+ * Add this to the list of pcaps to close when we exit.
+ */
+ pcap_add_to_pcaps_to_close(handle);
- return 1;
+ return 1;
+}
+#endif /* IW_MODE_MONITOR */
- } while(0);
+/*
+ * Try various mechanisms to enter monitor mode.
+ */
+static int
+enter_rfmon_mode(pcap_t *handle, int sock_fd, const char *device)
+{
+#if defined(HAVE_LIBNL) || defined(IW_MODE_MONITOR)
+ int ret;
+#endif
- if (sock_fd != -1)
- close(sock_fd);
+#ifdef HAVE_LIBNL
+ ret = enter_rfmon_mode_mac80211(handle, sock_fd, device);
+ if (ret < 0)
+ return ret; /* error attempting to do so */
+ if (ret == 1)
+ return 1; /* success */
+#endif /* HAVE_LIBNL */
+
+#ifdef IW_MODE_MONITOR
+ ret = enter_rfmon_mode_wext(handle, sock_fd, device);
+ if (ret < 0)
+ return ret; /* error attempting to do so */
+ if (ret == 1)
+ return 1; /* success */
+#endif /* IW_MODE_MONITOR */
- if (fatal_err)
- return -2;
- else
- return 0;
-#else
- strncpy(ebuf,
- "New packet capturing interface not supported by build "
- "environment", PCAP_ERRBUF_SIZE);
+ /*
+ * Either none of the mechanisms we know about work or none
+ * of those mechanisms are available, so we can't do monitor
+ * mode.
+ */
return 0;
-#endif
}
-#ifdef HAVE_PF_PACKET_SOCKETS
/*
- * Return the index of the given device name. Fill ebuf and return
- * -1 on failure.
+ * Find out if we have any form of fragmentation/reassembly offloading.
+ *
+ * We do so using SIOCETHTOOL checking for various types of offloading;
+ * if SIOCETHTOOL isn't defined, or we don't have any #defines for any
+ * of the types of offloading, there's nothing we can do to check, so
+ * we just say "no, we don't".
*/
+#if defined(SIOCETHTOOL) && (defined(ETHTOOL_GTSO) || defined(ETHTOOL_GUFO) || defined(ETHTOOL_GGSO) || defined(ETHTOOL_GFLAGS) || defined(ETHTOOL_GGRO))
static int
-iface_get_id(int fd, const char *device, char *ebuf)
+iface_ethtool_ioctl(pcap_t *handle, int cmd, const char *cmdname)
{
struct ifreq ifr;
+ struct ethtool_value eval;
memset(&ifr, 0, sizeof(ifr));
- strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
-
- if (ioctl(fd, SIOCGIFINDEX, &ifr) == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "ioctl: %s", pcap_strerror(errno));
+ strncpy(ifr.ifr_name, handle->opt.source, sizeof(ifr.ifr_name));
+ eval.cmd = cmd;
+ ifr.ifr_data = (caddr_t)&eval;
+ if (ioctl(handle->fd, SIOCETHTOOL, &ifr) == -1) {
+ if (errno == EOPNOTSUPP || errno == EINVAL) {
+ /*
+ * OK, let's just return 0, which, in our
+ * case, either means "no, what we're asking
+ * about is not enabled" or "all the flags
+ * are clear (i.e., nothing is enabled)".
+ */
+ return 0;
+ }
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: SIOETHTOOL(%s) ioctl failed: %s", handle->opt.source,
+ cmdname, strerror(errno));
return -1;
}
-
- return ifr.ifr_ifindex;
+ return eval.data;
}
-/*
- * Bind the socket associated with FD to the given device.
- */
static int
-iface_bind(int fd, int ifindex, char *ebuf)
+iface_get_offload(pcap_t *handle)
{
- struct sockaddr_ll sll;
- int err;
- socklen_t errlen = sizeof(err);
+ int ret;
- memset(&sll, 0, sizeof(sll));
- sll.sll_family = AF_PACKET;
- sll.sll_ifindex = ifindex;
- sll.sll_protocol = htons(ETH_P_ALL);
+#ifdef ETHTOOL_GTSO
+ ret = iface_ethtool_ioctl(handle, ETHTOOL_GTSO, "ETHTOOL_GTSO");
+ if (ret == -1)
+ return -1;
+ if (ret)
+ return 1; /* TCP segmentation offloading on */
+#endif
- if (bind(fd, (struct sockaddr *) &sll, sizeof(sll)) == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "bind: %s", pcap_strerror(errno));
+#ifdef ETHTOOL_GUFO
+ ret = iface_ethtool_ioctl(handle, ETHTOOL_GUFO, "ETHTOOL_GUFO");
+ if (ret == -1)
return -1;
- }
+ if (ret)
+ return 1; /* UDP fragmentation offloading on */
+#endif
- /* Any pending errors, e.g., network is down? */
+#ifdef ETHTOOL_GGSO
+ /*
+ * XXX - will this cause large unsegmented packets to be
+ * handed to PF_PACKET sockets on transmission? If not,
+ * this need not be checked.
+ */
+ ret = iface_ethtool_ioctl(handle, ETHTOOL_GGSO, "ETHTOOL_GGSO");
+ if (ret == -1)
+ return -1;
+ if (ret)
+ return 1; /* generic segmentation offloading on */
+#endif
- if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &errlen) == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "getsockopt: %s", pcap_strerror(errno));
- return -2;
- }
+#ifdef ETHTOOL_GFLAGS
+ ret = iface_ethtool_ioctl(handle, ETHTOOL_GFLAGS, "ETHTOOL_GFLAGS");
+ if (ret == -1)
+ return -1;
+ if (ret & ETH_FLAG_LRO)
+ return 1; /* large receive offloading on */
+#endif
- if (err > 0) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "bind: %s", pcap_strerror(err));
- return -2;
- }
+#ifdef ETHTOOL_GGRO
+ /*
+ * XXX - will this cause large reassembled packets to be
+ * handed to PF_PACKET sockets on receipt? If not,
+ * this need not be checked.
+ */
+ ret = iface_ethtool_ioctl(handle, ETHTOOL_GGRO, "ETHTOOL_GGRO");
+ if (ret == -1)
+ return -1;
+ if (ret)
+ return 1; /* generic (large) receive offloading on */
+#endif
return 0;
}
-
-#endif
-
-
-/* ===== Functions to interface to the older kernels ================== */
-
-/*
- * With older kernels promiscuous mode is kind of interesting because we
- * have to reset the interface before exiting. The problem can't really
- * be solved without some daemon taking care of managing usage counts.
- * If we put the interface into promiscuous mode, we set a flag indicating
- * that we must take it out of that mode when the interface is closed,
- * and, when closing the interface, if that flag is set we take it out
- * of promiscuous mode.
- */
-
-/*
- * List of pcaps for which we turned promiscuous mode on by hand.
- * If there are any such pcaps, we arrange to call "pcap_close_all()"
- * when we exit, and have it close all of them to turn promiscuous mode
- * off.
- */
-static struct pcap *pcaps_to_close;
-
-/*
- * TRUE if we've already called "atexit()" to cause "pcap_close_all()" to
- * be called on exit.
- */
-static int did_atexit;
-
-static void pcap_close_all(void)
+#else /* SIOCETHTOOL */
+static int
+iface_get_offload(pcap_t *handle _U_)
{
- struct pcap *handle;
-
- while ((handle = pcaps_to_close) != NULL)
- pcap_close(handle);
+ /*
+ * XXX - do we need to get this information if we don't
+ * have the ethtool ioctls? If so, how do we do that?
+ */
+ return 0;
}
+#endif /* SIOCETHTOOL */
-static void pcap_close_linux( pcap_t *handle )
-{
- struct pcap *p, *prevp;
- struct ifreq ifr;
-
- if (handle->md.clear_promisc) {
- /*
- * We put the interface into promiscuous mode; take
- * it out of promiscuous mode.
- *
- * XXX - if somebody else wants it in promiscuous mode,
- * this code cannot know that, so it'll take it out
- * of promiscuous mode. That's not fixable in 2.0[.x]
- * kernels.
- */
- memset(&ifr, 0, sizeof(ifr));
- strncpy(ifr.ifr_name, handle->md.device, sizeof(ifr.ifr_name));
- if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) == -1) {
- fprintf(stderr,
- "Can't restore interface flags (SIOCGIFFLAGS failed: %s).\n"
- "Please adjust manually.\n"
- "Hint: This can't happen with Linux >= 2.2.0.\n",
- strerror(errno));
- } else {
- if (ifr.ifr_flags & IFF_PROMISC) {
- /*
- * Promiscuous mode is currently on; turn it
- * off.
- */
- ifr.ifr_flags &= ~IFF_PROMISC;
- if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1) {
- fprintf(stderr,
- "Can't restore interface flags (SIOCSIFFLAGS failed: %s).\n"
- "Please adjust manually.\n"
- "Hint: This can't happen with Linux >= 2.2.0.\n",
- strerror(errno));
- }
- }
- }
-
- /*
- * Take this pcap out of the list of pcaps for which we
- * have to take the interface out of promiscuous mode.
- */
- for (p = pcaps_to_close, prevp = NULL; p != NULL;
- prevp = p, p = p->md.next) {
- if (p == handle) {
- /*
- * Found it. Remove it from the list.
- */
- if (prevp == NULL) {
- /*
- * It was at the head of the list.
- */
- pcaps_to_close = p->md.next;
- } else {
- /*
- * It was in the middle of the list.
- */
- prevp->md.next = p->md.next;
- }
- break;
- }
- }
- }
+#endif /* HAVE_PF_PACKET_SOCKETS */
- if (handle->md.device != NULL)
- free(handle->md.device);
- handle->md.device = NULL;
- if (handle->buffer != NULL)
- free(handle->buffer);
- if (handle->fd >= 0)
- close(handle->fd);
-}
+/* ===== Functions to interface to the older kernels ================== */
/*
- * Try to open a packet socket using the old kernel interface.
- * Returns 0 on failure.
- * FIXME: 0 uses to mean success (Sebastian)
+ * Try to open a packet socket using the old kernel interface.
+ * Returns 1 on success and a PCAP_ERROR_ value on an error.
*/
static int
-live_open_old(pcap_t *handle, const char *device, int promisc,
- int to_ms, char *ebuf)
+activate_old(pcap_t *handle)
{
int arptype;
struct ifreq ifr;
+ const char *device = handle->opt.source;
+ struct utsname utsname;
+ int mtu;
- do {
- /* Open the socket */
+ /* Open the socket */
- handle->fd = socket(PF_INET, SOCK_PACKET, htons(ETH_P_ALL));
- if (handle->fd == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "socket: %s", pcap_strerror(errno));
- break;
+ handle->fd = socket(PF_INET, SOCK_PACKET, htons(ETH_P_ALL));
+ if (handle->fd == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "socket: %s", pcap_strerror(errno));
+ if (errno == EPERM || errno == EACCES) {
+ /*
+ * You don't have permission to open the
+ * socket.
+ */
+ return PCAP_ERROR_PERM_DENIED;
+ } else {
+ /*
+ * Other error.
+ */
+ return PCAP_ERROR;
}
+ }
- /* It worked - we are using the old interface */
- handle->md.sock_packet = 1;
+ /* It worked - we are using the old interface */
+ handle->md.sock_packet = 1;
- /* ...which means we get the link-layer header. */
- handle->md.cooked = 0;
+ /* ...which means we get the link-layer header. */
+ handle->md.cooked = 0;
- /* Bind to the given device */
+ /* Bind to the given device */
- if (!device) {
- strncpy(ebuf, "pcap_open_live: The \"any\" device isn't supported on 2.0[.x]-kernel systems",
- PCAP_ERRBUF_SIZE);
- break;
- }
- if (iface_bind_old(handle->fd, device, ebuf) == -1)
- break;
+ if (strcmp(device, "any") == 0) {
+ strncpy(handle->errbuf, "pcap_activate: The \"any\" device isn't supported on 2.0[.x]-kernel systems",
+ PCAP_ERRBUF_SIZE);
+ return PCAP_ERROR;
+ }
+ if (iface_bind_old(handle->fd, device, handle->errbuf) == -1)
+ return PCAP_ERROR;
- /*
- * Try to get the link-layer type.
- */
- arptype = iface_get_arptype(handle->fd, device, ebuf);
- if (arptype == -1)
- break;
+ /*
+ * Try to get the link-layer type.
+ */
+ arptype = iface_get_arptype(handle->fd, device, handle->errbuf);
+ if (arptype < 0)
+ return PCAP_ERROR;
- /*
- * Try to find the DLT_ type corresponding to that
- * link-layer type.
- */
- map_arphrd_to_dlt(handle, arptype, 0);
- if (handle->linktype == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "unknown arptype %d", arptype);
- break;
- }
+ /*
+ * Try to find the DLT_ type corresponding to that
+ * link-layer type.
+ */
+ map_arphrd_to_dlt(handle, handle->fd, arptype, device, 0);
+ if (handle->linktype == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "unknown arptype %d", arptype);
+ return PCAP_ERROR;
+ }
- /* Go to promisc mode if requested */
+ /* Go to promisc mode if requested */
- if (promisc) {
- memset(&ifr, 0, sizeof(ifr));
- strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
- if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "ioctl: %s", pcap_strerror(errno));
- break;
- }
- if ((ifr.ifr_flags & IFF_PROMISC) == 0) {
- /*
- * Promiscuous mode isn't currently on,
- * so turn it on, and remember that
- * we should turn it off when the
- * pcap_t is closed.
- */
+ if (handle->opt.promisc) {
+ memset(&ifr, 0, sizeof(ifr));
+ strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
+ if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "SIOCGIFFLAGS: %s", pcap_strerror(errno));
+ return PCAP_ERROR;
+ }
+ if ((ifr.ifr_flags & IFF_PROMISC) == 0) {
+ /*
+ * Promiscuous mode isn't currently on,
+ * so turn it on, and remember that
+ * we should turn it off when the
+ * pcap_t is closed.
+ */
+ /*
+ * If we haven't already done so, arrange
+ * to have "pcap_close_all()" called when
+ * we exit.
+ */
+ if (!pcap_do_addexit(handle)) {
/*
- * If we haven't already done so, arrange
- * to have "pcap_close_all()" called when
- * we exit.
+ * "atexit()" failed; don't put
+ * the interface in promiscuous
+ * mode, just give up.
*/
- if (!did_atexit) {
- if (atexit(pcap_close_all) == -1) {
- /*
- * "atexit()" failed; don't
- * put the interface in
- * promiscuous mode, just
- * give up.
- */
- strncpy(ebuf, "atexit failed",
- PCAP_ERRBUF_SIZE);
- break;
- }
- did_atexit = 1;
- }
-
- ifr.ifr_flags |= IFF_PROMISC;
- if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "ioctl: %s",
- pcap_strerror(errno));
- break;
- }
- handle->md.clear_promisc = 1;
+ return PCAP_ERROR;
+ }
- /*
- * Add this to the list of pcaps
- * to close when we exit.
- */
- handle->md.next = pcaps_to_close;
- pcaps_to_close = handle;
+ ifr.ifr_flags |= IFF_PROMISC;
+ if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "SIOCSIFFLAGS: %s",
+ pcap_strerror(errno));
+ return PCAP_ERROR;
}
+ handle->md.must_do_on_close |= MUST_CLEAR_PROMISC;
+
+ /*
+ * Add this to the list of pcaps
+ * to close when we exit.
+ */
+ pcap_add_to_pcaps_to_close(handle);
}
+ }
+ /*
+ * Compute the buffer size.
+ *
+ * We're using SOCK_PACKET, so this might be a 2.0[.x]
+ * kernel, and might require special handling - check.
+ */
+ if (uname(&utsname) < 0 ||
+ strncmp(utsname.release, "2.0", 3) == 0) {
+ /*
+ * Either we couldn't find out what kernel release
+ * this is, or it's a 2.0[.x] kernel.
+ *
+ * In the 2.0[.x] kernel, a "recvfrom()" on
+ * a SOCK_PACKET socket, with MSG_TRUNC set, will
+ * return the number of bytes read, so if we pass
+ * a length based on the snapshot length, it'll
+ * return the number of bytes from the packet
+ * copied to userland, not the actual length
+ * of the packet.
+ *
+ * This means that, for example, the IP dissector
+ * in tcpdump will get handed a packet length less
+ * than the length in the IP header, and will
+ * complain about "truncated-ip".
+ *
+ * So we don't bother trying to copy from the
+ * kernel only the bytes in which we're interested,
+ * but instead copy them all, just as the older
+ * versions of libpcap for Linux did.
+ *
+ * The buffer therefore needs to be big enough to
+ * hold the largest packet we can get from this
+ * device. Unfortunately, we can't get the MRU
+ * of the network; we can only get the MTU. The
+ * MTU may be too small, in which case a packet larger
+ * than the buffer size will be truncated *and* we
+ * won't get the actual packet size.
+ *
+ * However, if the snapshot length is larger than
+ * the buffer size based on the MTU, we use the
+ * snapshot length as the buffer size, instead;
+ * this means that with a sufficiently large snapshot
+ * length we won't artificially truncate packets
+ * to the MTU-based size.
+ *
+ * This mess just one of many problems with packet
+ * capture on 2.0[.x] kernels; you really want a
+ * 2.2[.x] or later kernel if you want packet capture
+ * to work well.
+ */
+ mtu = iface_get_mtu(handle->fd, device, handle->errbuf);
+ if (mtu == -1)
+ return PCAP_ERROR;
+ handle->bufsize = MAX_LINKHEADER_SIZE + mtu;
+ if (handle->bufsize < handle->snapshot)
+ handle->bufsize = handle->snapshot;
+ } else {
/*
- * Default value for offset to align link-layer payload
- * on a 4-byte boundary.
+ * This is a 2.2[.x] or later kernel.
+ *
+ * We can safely pass "recvfrom()" a byte count
+ * based on the snapshot length.
*/
- handle->offset = 0;
+ handle->bufsize = handle->snapshot;
+ }
- return 1;
+ /*
+ * Default value for offset to align link-layer payload
+ * on a 4-byte boundary.
+ */
+ handle->offset = 0;
- } while (0);
+ /*
+ * SOCK_PACKET sockets don't supply information from
+ * stripped VLAN tags.
+ */
+ handle->md.vlan_offset = -1; /* unknown */
- pcap_close_linux(handle);
- return 0;
+ return 1;
}
/*
if (ioctl(fd, SIOCGIFMTU, &ifr) == -1) {
snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "ioctl: %s", pcap_strerror(errno));
+ "SIOCGIFMTU: %s", pcap_strerror(errno));
return -1;
}
if (ioctl(fd, SIOCGIFHWADDR, &ifr) == -1) {
snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "ioctl: %s", pcap_strerror(errno));
- return -1;
+ "SIOCGIFHWADDR: %s", pcap_strerror(errno));
+ if (errno == ENODEV) {
+ /*
+ * No such device.
+ */
+ return PCAP_ERROR_NO_SUCH_DEVICE;
+ }
+ return PCAP_ERROR;
}
return ifr.ifr_hwaddr.sa_family;
#ifdef SO_ATTACH_FILTER
static int
-fix_program(pcap_t *handle, struct sock_fprog *fcode)
+fix_program(pcap_t *handle, struct sock_fprog *fcode, int is_mmapped)
{
size_t prog_size;
register int i;
len = handle->fcode.bf_len;
f = (struct bpf_insn *)malloc(prog_size);
if (f == NULL) {
- snprintf(handle->errbuf, sizeof(handle->errbuf),
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"malloc: %s", pcap_strerror(errno));
return -1;
}
case BPF_RET:
/*
- * It's a return instruction; is the snapshot
- * length a constant, rather than the contents
- * of the accumulator?
+ * It's a return instruction; are we capturing
+ * in memory-mapped mode?
*/
- if (BPF_MODE(p->code) == BPF_K) {
+ if (!is_mmapped) {
/*
- * Yes - if the value to be returned,
- * i.e. the snapshot length, is anything
- * other than 0, make it 65535, so that
- * the packet is truncated by "recvfrom()",
- * not by the filter.
- *
- * XXX - there's nothing we can easily do
- * if it's getting the value from the
- * accumulator; we'd have to insert
- * code to force non-zero values to be
- * 65535.
+ * No; is the snapshot length a constant,
+ * rather than the contents of the
+ * accumulator?
*/
- if (p->k != 0)
- p->k = 65535;
+ if (BPF_MODE(p->code) == BPF_K) {
+ /*
+ * Yes - if the value to be returned,
+ * i.e. the snapshot length, is
+ * anything other than 0, make it
+ * 65535, so that the packet is
+ * truncated by "recvfrom()",
+ * not by the filter.
+ *
+ * XXX - there's nothing we can
+ * easily do if it's getting the
+ * value from the accumulator; we'd
+ * have to insert code to force
+ * non-zero values to be 65535.
+ */
+ if (p->k != 0)
+ p->k = 65535;
+ }
}
break;
* header.
*/
p->k -= SLL_HDR_LEN;
+ } else if (p->k == 0) {
+ /*
+ * It's the packet type field; map it to the special magic
+ * kernel offset for that field.
+ */
+ p->k = SKF_AD_OFF + SKF_AD_PKTTYPE;
} else if (p->k == 14) {
/*
* It's the protocol field; map it to the special magic
* kernel offset for that field.
*/
p->k = SKF_AD_OFF + SKF_AD_PROTOCOL;
- } else {
+ } else if ((bpf_int32)(p->k) > 0) {
/*
* It's within the header, but it's not one of those
* fields; we can't do that in the kernel, so punt
if (save_errno != EAGAIN) {
/* Fatal error */
reset_kernel_filter(handle);
- snprintf(handle->errbuf, sizeof(handle->errbuf),
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"recv: %s", pcap_strerror(save_errno));
return -2;
}
static int
reset_kernel_filter(pcap_t *handle)
{
- /* setsockopt() barfs unless it get a dummy parameter */
- int dummy;
+ /*
+ * setsockopt() barfs unless it get a dummy parameter.
+ * valgrind whines unless the value is initialized,
+ * as it has no idea that setsockopt() ignores its
+ * parameter.
+ */
+ int dummy = 0;
return setsockopt(handle->fd, SOL_SOCKET, SO_DETACH_FILTER,
&dummy, sizeof(dummy));
projects / libpcap / blobdiff