+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
+
+/*
+ * Known problems with 2.0[.x] kernels:
+ *
+ * - The loopback device gives every packet twice; on 2.2[.x] kernels,
+ * if we use PF_PACKET, we can filter out the transmitted version
+ * of the packet by using data in the "sockaddr_ll" returned by
+ * "recvfrom()", but, on 2.0[.x] kernels, we have to use
+ * PF_INET/SOCK_PACKET, which means "recvfrom()" supplies a
+ * "sockaddr_pkt" which doesn't give us enough information to let
+ * us do that.
+ *
+ * - We have to set the interface's IFF_PROMISC flag ourselves, if
+ * we're to run in promiscuous mode, which means we have to turn
+ * it off ourselves when we're done; the kernel doesn't keep track
+ * of how many sockets are listening promiscuously, which means
+ * it won't get turned off automatically when no sockets are
+ * listening promiscuously. We catch "pcap_close()" and, for
+ * interfaces we put into promiscuous mode, take them out of
+ * promiscuous mode - which isn't necessarily the right thing to
+ * do, if another socket also requested promiscuous mode between
+ * the time when we opened the socket and the time when we close
+ * the socket.
+ *
+ * - MSG_TRUNC isn't supported, so you can't specify that "recvfrom()"
+ * return the amount of data that you could have read, rather than
+ * the amount that was returned, so we can't just allocate a buffer
+ * whose size is the snapshot length and pass the snapshot length
+ * as the byte count, and also pass MSG_TRUNC, so that the return
+ * value tells us how long the packet was on the wire.
+ *
+ * This means that, if we want to get the actual size of the packet,
+ * so we can return it in the "len" field of the packet header,
+ * we have to read the entire packet, not just the part that fits
+ * within the snapshot length, and thus waste CPU time copying data
+ * from the kernel that our caller won't see.
+ *
+ * We have to get the actual size, and supply it in "len", because
+ * otherwise, the IP dissector in tcpdump, for example, will complain
+ * about "truncated-ip", as the packet will appear to have been
+ * shorter, on the wire, than the IP header said it should have been.
+ */
+
+
+#define _GNU_SOURCE
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#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/socket.h>
+#include <sys/ioctl.h>
+#include <sys/utsname.h>
+#include <sys/mman.h>
+#include <linux/if.h>
+#include <netinet/in.h>
+#include <linux/if_ether.h>
+#include <net/if_arp.h>
+#include <poll.h>
+#include <dirent.h>
+
+#ifdef HAVE_LINUX_NET_TSTAMP_H
+#include <linux/net_tstamp.h>
+#include <linux/sockios.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 */
+
+#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 PF_PACKET is defined, we can use {SOCK_RAW,SOCK_DGRAM}/PF_PACKET
+ * sockets rather than SOCK_PACKET sockets.
+ *
+ * To use them, we include <linux/if_packet.h> rather than
+ * <netpacket/packet.h>; we do so because
+ *
+ * some Linux distributions (e.g., Slackware 4.0) have 2.2 or
+ * later kernels and libc5, and don't provide a <netpacket/packet.h>
+ * file;
+ *
+ * not all versions of glibc2 have a <netpacket/packet.h> file
+ * that defines stuff needed for some of the 2.4-or-later-kernel
+ * features, so if the system has a 2.4 or later kernel, we
+ * still can't use those features.
+ *
+ * We're already including a number of other <linux/XXX.h> headers, and
+ * this code is Linux-specific (no other OS has PF_PACKET sockets as
+ * a raw packet capture mechanism), so it's not as if you gain any
+ * useful portability by using <netpacket/packet.h>
+ *
+ * XXX - should we just include <linux/if_packet.h> even if PF_PACKET
+ * isn't defined? It only defines one data structure in 2.0.x, so
+ * it shouldn't cause any problems.
+ */
+#ifdef PF_PACKET
+# include <linux/if_packet.h>
+
+ /*
+ * On at least some Linux distributions (for example, Red Hat 5.2),
+ * there's no <netpacket/packet.h> file, but PF_PACKET is defined if
+ * you include <sys/socket.h>, but <linux/if_packet.h> doesn't define
+ * any of the PF_PACKET stuff such as "struct sockaddr_ll" or any of
+ * the PACKET_xxx stuff.
+ *
+ * So we check whether PACKET_HOST is defined, and assume that we have
+ * PF_PACKET sockets only if it is defined.
+ */
+# 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/types.h>
+#include <linux/filter.h>
+#endif
+
+#ifndef HAVE_SOCKLEN_T
+typedef int socklen_t;
+#endif
+
+#ifndef MSG_TRUNC
+/*
+ * This is being compiled on a system that lacks MSG_TRUNC; define it
+ * with the value it has in the 2.2 and later kernels, so that, on
+ * those kernels, when we pass it in the flags argument to "recvfrom()"
+ * we're passing the right value and thus get the MSG_TRUNC behavior
+ * we want. (We don't get that behavior on 2.0[.x] kernels, because
+ * they didn't support MSG_TRUNC.)
+ */
+#define MSG_TRUNC 0x20
+#endif
+
+#ifndef SOL_PACKET
+/*
+ * This is being compiled on a system that lacks SOL_PACKET; define it
+ * with the value it has in the 2.2 and later kernels, so that we can
+ * set promiscuous mode in the good modern way rather than the old
+ * 2.0-kernel crappy way.
+ */
+#define SOL_PACKET 263
+#endif
+
+#define MAX_LINKHEADER_SIZE 256
+
+/*
+ * When capturing on all interfaces we use this as the buffer size.
+ * Should be bigger then all MTUs that occur in real life.
+ * 64kB should be enough for now.
+ */
+#define BIGGER_THAN_ALL_MTUS (64*1024)
+
+/*
+ * Prototypes for internal functions and methods.
+ */
+static void map_arphrd_to_dlt(pcap_t *, int, 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 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
+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);
+#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_bind_old(int fd, const char *device, char *ebuf);
+
+#ifdef SO_ATTACH_FILTER
+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);
+
+static struct sock_filter total_insn
+ = BPF_STMT(BPF_RET | BPF_K, 0);
+static struct sock_fprog total_fcode
+ = { 1, &total_insn };
+#endif
+
+pcap_t *
+pcap_create(const char *device, char *ebuf)
+{
+ 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_create(device, ebuf);
+ }
+#endif /* HAVE_DAG_API */
+
+#ifdef HAVE_SEPTEL_API
+ if (strstr(device, "septel")) {
+ return septel_create(device, ebuf);
+ }
+#endif /* HAVE_SEPTEL_API */
+
+#ifdef HAVE_SNF_API
+ handle = snf_create(device, ebuf);
+ if (strstr(device, "snf") || handle != NULL)
+ return handle;
+
+#endif /* HAVE_SNF_API */
+
+#ifdef PCAP_SUPPORT_BT
+ if (strstr(device, "bluetooth")) {
+ return bt_create(device, ebuf);
+ }
+#endif
+
+#ifdef PCAP_SUPPORT_CAN
+ if (strstr(device, "can") || strstr(device, "vcan")) {
+ return can_create(device, ebuf);
+ }
+#endif
+
+#ifdef PCAP_SUPPORT_USB
+ if (strstr(device, "usbmon")) {
+ return usb_create(device, ebuf);
+ }
+#endif
+
+ 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)
+ /*
+ * 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.
+ *
+ * XXX - we can't ask a device whether it supports
+ * hardware time stamps, so we just claim all devices do.
+ */
+ 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->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
+/*
+ * 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.
+*/
+
+/*
+ * 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
+get_mac80211_phydev(pcap_t *handle, const char *device, char *phydev_path,
+ size_t phydev_max_pathlen)
+{
+ char *pathstr;
+ ssize_t bytes_read;
+
+ /*
+ * Generate the path string for the symlink to the physical device.
+ */
+ 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;
+}
+
+#ifndef HAVE_LIBNL_2_x
+/* libnl 2.x compatibility code */
+
+#define nl_sock nl_handle
+
+static inline struct nl_handle *
+nl_socket_alloc(void)
+{
+ return nl_handle_alloc();
+}
+
+static inline void
+nl_socket_free(struct nl_handle *h)
+{
+ nl_handle_destroy(h);
+}
+
+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 */
+
+struct nl80211_state {
+ struct nl_sock *nl_sock;
+ struct nl_cache *nl_cache;
+ struct genl_family *nl80211;
+};
+
+static int
+nl80211_init(pcap_t *handle, struct nl80211_state *state, const char *device)
+{
+ int err;
+
+ 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;
+ }
+
+ if (genl_connect(state->nl_sock)) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: failed to connect to generic netlink", device);
+ goto out_handle_destroy;
+ }
+
+ 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, strerror(-err));
+ goto out_handle_destroy;
+ }
+
+ 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;
+ }
+
+ return 0;
+
+out_cache_free:
+ nl_cache_free(state->nl_cache);
+out_handle_destroy:
+ nl_socket_free(state->nl_sock);
+ return PCAP_ERROR;
+}
+
+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) {
+ if (err == -ENFILE) {
+ /*
+ * Device not available; our caller should just
+ * keep trying.
+ */
+ 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, strerror(-err));
+ nlmsg_free(msg);
+ return PCAP_ERROR;
+ }
+ }
+ err = nl_wait_for_ack(state->nl_sock);
+ if (err < 0) {
+ if (err == -ENFILE) {
+ /*
+ * Device not available; our caller should just
+ * keep trying.
+ */
+ 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, strerror(-err));
+ nlmsg_free(msg);
+ return PCAP_ERROR;
+ }
+ }
+
+ /*
+ * Success.
+ */
+ nlmsg_free(msg);
+ return 1;
+
+nla_put_failure:
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: nl_put failed adding %s interface",
+ device, mondevice);
+ nlmsg_free(msg);
+ return PCAP_ERROR;
+}
+
+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;
+ }
+
+ 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) {
+ if (err == -ENFILE) {
+ /*
+ * Device not available; our caller should just
+ * keep trying.
+ */
+ 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 deleting %s interface: %s",
+ device, mondevice, strerror(-err));
+ nlmsg_free(msg);
+ return PCAP_ERROR;
+ }
+ }
+ err = nl_wait_for_ack(state->nl_sock);
+ if (err < 0) {
+ if (err == -ENFILE) {
+ /*
+ * Device not available; our caller should just
+ * keep trying.
+ */
+ 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, strerror(-err));
+ nlmsg_free(msg);
+ return PCAP_ERROR;
+ }
+ }
+
+ /*
+ * Success.
+ */
+ 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;
+}
+
+static int
+enter_rfmon_mode_mac80211(pcap_t *handle, int sock_fd, const char *device)
+{
+ int ret;
+ char phydev_path[PATH_MAX+1];
+ struct nl80211_state nlstate;
+ struct ifreq ifr;
+ u_int n;
+
+ /*
+ * Is this a mac80211 device?
+ */
+ 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++) {
+ /*
+ * Try mon{n}.
+ */
+ 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
+
+ /*
+ * 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;
+ }
+
+ /*
+ * Success. Clean up the libnl state.
+ */
+ nl80211_cleanup(&nlstate);
+
+ /*
+ * Note that we have to delete the monitor device when we close
+ * the handle.
+ */
+ handle->md.must_do_on_close |= MUST_DELETE_MONIF;
+
+ /*
+ * Add this to the list of pcaps to close when we exit.
+ */
+ pcap_add_to_pcaps_to_close(handle);
+
+ return 1;
+}
+#endif /* HAVE_LIBNL */
+
+static int
+pcap_can_set_rfmon_linux(pcap_t *handle)
+{
+#ifdef HAVE_LIBNL
+ char phydev_path[PATH_MAX+1];
+ int ret;
+#endif
+#ifdef IW_MODE_MONITOR
+ int sock_fd;
+ struct iwreq ireq;
+#endif
+
+ if (strcmp(handle->opt.source, "any") == 0) {
+ /*
+ * Monitor mode makes no sense on the "any" device.
+ */
+ return 0;
+ }
+
+#ifdef HAVE_LIBNL
+ /*
+ * 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.
+ */
+ 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
+
+#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;
+ }
+
+ /*
+ * 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) {
+ /*
+ * Well, we got the mode; assume we can set it.
+ */
+ 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
+ struct iwreq ireq;
+#endif /* IW_MODE_MONITOR */
+
+ if (handle->md.must_do_on_close != 0) {
+ /*
+ * There's something we have to do when closing this
+ * pcap_t.
+ */
+ if (handle->md.must_do_on_close & MUST_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));
+ }
+ }
+ }
+ }
+
+#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) {
+ /*
+ * 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.
+ */
+ 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,
+ "Can't restore interface wireless mode (SIOCSIWMODE failed: %s).\n"
+ "Please adjust manually.\n",
+ strerror(errno));
+ }
+ }
+#endif /* IW_MODE_MONITOR */
+
+ /*
+ * 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);
+ }
+
+ 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);
+}
+
+/*
+ * 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 int
+pcap_activate_linux(pcap_t *handle)
+{
+ const char *device;
+ int status = 0;
+
+ device = handle->opt.source;
+
+ 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;
+
+ /*
+ * 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;
+ }
+ }
+
+ 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)
+ 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 (aux->tp_vlan_tci == 0)
+ continue;
+
+ len = packet_len > iov.iov_len ? iov.iov_len : packet_len;
+ if (len < 2 * ETH_ALEN)
+ break;
+
+ bp -= VLAN_TAG_LEN;
+ memmove(bp, bp + VLAN_TAG_LEN, 2 * ETH_ALEN);
+
+ tag = (struct vlan_tag *)(bp + 2 * ETH_ALEN);
+ 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 *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 && errno == ENOENT)
+ return (0);
+
+ /*
+ * 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));
+ 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 directories (".", "..", and any subdirectories).
+ */
+ if (ent->d_type == DT_DIR)
+ 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 && errno == ENOENT)
+ return (0);
+
+ /*
+ * 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));
+ 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
+
+ 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;
+ }
+ }
+
+ 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
+
+/*
+ * 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 arptype, int cooked_ok)
+{
+ switch (arptype) {
+
+ case ARPHRD_ETHER:
+ /*
+ * This is (presumably) a real Ethernet capture; 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 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; are there any
+ * others?
+ */
+ 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) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "socket: %s",
+ pcap_strerror(errno) );
+ return 0; /* try old mechanism */
+ }
+
+ /* 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, arptype, 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));
+ 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;
+
+ /* 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
+}
+
+#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;
+
+ /*
+ * Start out assuming no warnings or errors.
+ */
+ *status = 0;
+
+ /* Note that with large snapshot (say 64K) only a few frames
+ * will be available in the ring even with pretty large ring size
+ * (and a lot of memory will be unused).
+ * The snap len should be carefully chosen to achive best
+ * performance */
+ req.tp_frame_size = TPACKET_ALIGN(handle->snapshot +
+ TPACKET_ALIGN(handle->md.tp_hdrlen) +
+ sizeof(struct sockaddr_ll));
+ 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 POLLRDHUP
+#define POLLRDHUP 0
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