#ifndef lint
static const char rcsid[] _U_ =
- "@(#) $Header: /tcpdump/master/libpcap/pcap-linux.c,v 1.129.2.4 2008-01-06 20:24:13 guy Exp $ (LBL)";
+ "@(#) $Header: /tcpdump/master/libpcap/pcap-linux.c,v 1.129.2.22 2008-08-06 07:40:20 guy Exp $ (LBL)";
#endif
/*
#include "config.h"
#endif
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <sys/utsname.h>
+#include <sys/mman.h>
+#include <net/if.h>
+#include <netinet/in.h>
+#include <linux/if_ether.h>
+#include <net/if_arp.h>
+#include <poll.h>
+
+/*
+ * Got Wireless Extensions?
+ */
+#ifdef HAVE_LINUX_WIRELESS_H
+#include <linux/wireless.h>
+#endif
+
#include "pcap-int.h"
#include "pcap/sll.h"
#include "pcap-bt-linux.h"
#endif
-#include <errno.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <fcntl.h>
-#include <string.h>
-#include <sys/socket.h>
-#include <sys/ioctl.h>
-#include <sys/utsname.h>
-#include <sys/mman.h>
-#include <net/if.h>
-#include <netinet/in.h>
-#include <linux/if_ether.h>
-#include <net/if_arp.h>
-#include <poll.h>
-
/*
* If PF_PACKET is defined, we can use {SOCK_RAW,SOCK_DGRAM}/PF_PACKET
* sockets rather than SOCK_PACKET sockets.
#include <linux/filter.h>
#endif
-#ifndef __GLIBC__
+#ifndef HAVE_SOCKLEN_T
typedef int socklen_t;
#endif
#define BIGGER_THAN_ALL_MTUS (64*1024)
/*
- * Prototypes for internal functions
+ * Prototypes for internal functions and methods.
*/
static void map_arphrd_to_dlt(pcap_t *, int, int);
+#ifdef HAVE_PF_PACKET_SOCKETS
static short int map_packet_type_to_sll_type(short int);
-static int live_open_old(pcap_t *, const char *, int, int, char *);
-static int live_open_new(pcap_t *, const char *, int, int, char *);
-static int live_open_mmap(pcap_t *, char *);
+#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 *);
+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_close_linux(pcap_t *);
+static void pcap_cleanup_linux(pcap_t *);
#ifdef HAVE_PACKET_RING
-#define RING_GET_FRAME(h) (((struct tpacket_hdr**)h->buffer)[handle->offset])
+#define RING_GET_FRAME(h) (((struct tpacket_hdr**)h->buffer)[h->offset])
static void destroy_ring(pcap_t *handle);
-static int create_ring(pcap_t* handle, unsigned size, char* errmsg);
-static void pcap_close_linux_mmap(pcap_t *);
+static int create_ring(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 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);
+static int has_wext(int sock_fd, const char *device, char *ebuf);
+static int enter_rfmon_mode_wext(pcap_t *handle, int sock_fd,
+ const char *device);
#endif
static int iface_bind_old(int fd, const char *device, char *ebuf);
= { 1, &total_insn };
#endif
-/*
- * Get a handle for a live capture from the given device. You can
- * pass NULL as device to get all packages (without link level
- * information of course). If you pass 1 as promisc the interface
- * will be set to promiscous mode (XXX: I think this usage should
- * be deprecated and functions be added to select that later allow
- * modification of that values -- Torsten).
- *
- * See also pcap(3).
- */
pcap_t *
-pcap_open_live(const char *device, int snaplen, int promisc, int to_ms,
- char *ebuf)
+pcap_create(const char *device, char *ebuf)
{
- pcap_t *handle;
- int mtu;
- int err;
- int live_open_ok = 0;
- struct utsname utsname;
+ pcap_t *handle;
#ifdef HAVE_DAG_API
if (strstr(device, "dag")) {
- return dag_open_live(device, snaplen, promisc, to_ms, ebuf);
+ return dag_create(device, ebuf);
}
#endif /* HAVE_DAG_API */
#ifdef HAVE_SEPTEL_API
if (strstr(device, "septel")) {
- return septel_open_live(device, snaplen, promisc, to_ms, ebuf);
+ return septel_create(device, ebuf);
}
#endif /* HAVE_SEPTEL_API */
#ifdef PCAP_SUPPORT_BT
if (strstr(device, "bluetooth")) {
- return bt_open_live(device, snaplen, promisc, to_ms, ebuf);
+ return bt_create(device, ebuf);
}
#endif
#ifdef PCAP_SUPPORT_USB
if (strstr(device, "usb")) {
- return usb_open_live(device, snaplen, promisc, to_ms, ebuf);
+ return usb_create(device, ebuf);
}
#endif
- /* Allocate a handle for this session. */
-
- handle = malloc(sizeof(*handle));
- if (handle == NULL) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
- pcap_strerror(errno));
+ 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;
+ return handle;
+}
+
+static int
+pcap_can_set_rfmon_linux(pcap_t *p)
+{
+#ifdef IW_MODE_MONITOR
+ int sock_fd;
+ struct iwreq ireq;
+#endif
+
+ if (p->opt.source == NULL) {
+ /*
+ * This is equivalent to the "any" device, and we don't
+ * support monitor mode on it.
+ */
+ return 0;
+ }
+
+#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(p->errbuf, PCAP_ERRBUF_SIZE,
+ "socket: %s", pcap_strerror(errno));
+ return PCAP_ERROR;
+ }
+
+ /*
+ * Attempt to get the current mode.
+ */
+ strncpy(ireq.ifr_ifrn.ifrn_name, p->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. */
+ close(sock_fd);
+ return PCAP_ERROR_NO_SUCH_DEVICE;
+ }
+ close(sock_fd);
+#endif
+ return 0;
+}
+
+/*
+ * 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 IW_MODE_MONITOR
+ struct iwreq ireq;
+#endif
+
+ if (handle->md.must_clear != 0) {
+ /*
+ * There's something we have to do when closing this
+ * pcap_t.
+ */
+ if (handle->md.must_clear & 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 IW_MODE_MONITOR
+ if (handle->md.must_clear & 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
+
+ /*
+ * 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.device != NULL) {
+ free(handle->md.device);
+ handle->md.device = NULL;
}
+ pcap_cleanup_live_common(handle);
+}
- /* Initialize some components of the pcap structure. */
+/*
+ * 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;
+ int activate_ok = 0;
- memset(handle, 0, sizeof(*handle));
- handle->snapshot = snaplen;
- handle->md.timeout = to_ms;
+ device = handle->opt.source;
handle->inject_op = pcap_inject_linux;
handle->setfilter_op = pcap_setfilter_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->close_op = pcap_close_linux;
+ handle->cleanup_op = pcap_cleanup_linux;
handle->read_op = pcap_read_linux;
handle->stats_op = pcap_stats_linux;
if (!device || strcmp(device, "any") == 0) {
device = NULL;
handle->md.device = strdup("any");
- if (promisc) {
- promisc = 0;
+ if (handle->opt.promisc) {
+ handle->opt.promisc = 0;
/* Just a warning. */
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"Promiscuous mode not supported on the \"any\" device");
+ status = PCAP_WARNING_PROMISC_NOTSUP;
}
} else
handle->md.device = strdup(device);
if (handle->md.device == NULL) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE, "strdup: %s",
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "strdup: %s",
pcap_strerror(errno) );
- free(handle);
- return NULL;
+ return PCAP_ERROR;
}
/*
* trying both methods with the newer method preferred.
*/
- if ((err = live_open_new(handle, device, promisc, to_ms, ebuf)) == 1) {
- live_open_ok = 1;
- if (live_open_mmap(handle, ebuf) == 1)
- return handle;
+ if ((status = activate_new(handle)) == 1) {
+ activate_ok = 1;
+ /*
+ * Try to use memory-mapped access.
+ */
+ if (activate_mmap(handle) == 1)
+ return 0; /* we succeeded; nothing more to do */
}
- else if (err == 0) {
+ else if (status == 0) {
/* Non-fatal error; try old way */
- if (live_open_old(handle, device, promisc, to_ms, ebuf))
- live_open_ok = 1;
+ if ((status = activate_old(handle)) == 1)
+ activate_ok = 1;
}
- if (!live_open_ok) {
+ if (!activate_ok) {
/*
* Both methods to open the packet socket failed. Tidy
* up and report our failure (ebuf is expected to be
* set by the functions above).
*/
-
- if (handle->md.device != NULL)
- free(handle->md.device);
- free(handle);
- return NULL;
+ goto fail;
}
- /*
- * Compute the buffer size.
- *
- * If we're using SOCK_PACKET, this might be a 2.0[.x] kernel,
- * and might require special handling - check.
- */
- if (handle->md.sock_packet && (uname(&utsname) < 0 ||
- strncmp(utsname.release, "2.0", 3) == 0)) {
- /*
- * We're using a SOCK_PACKET structure, and either
- * we couldn't find out what kernel release this is,
- * or it's a 2.0[.x] kernel.
- *
- * In the 2.0[.x] kernel, a "recvfrom()" on
- * a SOCK_PACKET socket, with MSG_TRUNC set, will
- * return the number of bytes read, so if we pass
- * a length based on the snapshot length, it'll
- * return the number of bytes from the packet
- * copied to userland, not the actual length
- * of the packet.
- *
- * This means that, for example, the IP dissector
- * in tcpdump will get handed a packet length less
- * than the length in the IP header, and will
- * complain about "truncated-ip".
- *
- * So we don't bother trying to copy from the
- * kernel only the bytes in which we're interested,
- * but instead copy them all, just as the older
- * versions of libpcap for Linux did.
- *
- * The buffer therefore needs to be big enough to
- * hold the largest packet we can get from this
- * device. Unfortunately, we can't get the MRU
- * of the network; we can only get the MTU. The
- * MTU may be too small, in which case a packet larger
- * than the buffer size will be truncated *and* we
- * won't get the actual packet size.
- *
- * However, if the snapshot length is larger than
- * the buffer size based on the MTU, we use the
- * snapshot length as the buffer size, instead;
- * this means that with a sufficiently large snapshot
- * length we won't artificially truncate packets
- * to the MTU-based size.
- *
- * This mess just one of many problems with packet
- * capture on 2.0[.x] kernels; you really want a
- * 2.2[.x] or later kernel if you want packet capture
- * to work well.
- */
- mtu = iface_get_mtu(handle->fd, device, ebuf);
- if (mtu == -1) {
- pcap_close_linux(handle);
- free(handle);
- return NULL;
- }
- handle->bufsize = MAX_LINKHEADER_SIZE + mtu;
- if (handle->bufsize < handle->snapshot)
- handle->bufsize = handle->snapshot;
- } else {
+ if (handle->opt.buffer_size == 0) {
/*
- * This is a 2.2[.x] or later kernel (we know that
- * either because we're not using a SOCK_PACKET
- * socket - PF_PACKET is supported only in 2.2
- * and later kernels - or because we checked the
- * kernel version).
- *
- * We can safely pass "recvfrom()" a byte count
- * based on the snapshot length.
- *
- * 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()").
+ * Set the socket buffer size to the specified value.
*/
- if (handle->md.cooked) {
- if (handle->snapshot < SLL_HDR_LEN + 1)
- handle->snapshot = SLL_HDR_LEN + 1;
+ 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;
}
- handle->bufsize = handle->snapshot;
}
/* Allocate the buffer */
handle->buffer = malloc(handle->bufsize + handle->offset);
if (!handle->buffer) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"malloc: %s", pcap_strerror(errno));
- pcap_close_linux(handle);
- free(handle);
- return NULL;
+ status = PCAP_ERROR;
+ goto fail;
}
/*
*/
handle->selectable_fd = handle->fd;
- return handle;
+ return status;
+
+fail:
+ pcap_cleanup_linux(handle);
+ return status;
}
/*
#else
struct sockaddr from;
#endif
- socklen_t fromlen;
int packet_len, caplen;
struct pcap_pkthdr pcap_header;
-
+ struct iovec iov;
+ struct msghdr msg;
#ifdef HAVE_PF_PACKET_SOCKETS
/*
* If this is a cooked device, leave extra room for a
offset = 0;
#endif
- /* Receive a single packet from the kernel */
-
+ /*
+ * 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;
+
+ msg.msg_name = &from;
+ msg.msg_namelen = sizeof(from);
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+ msg.msg_control = NULL;
+ msg.msg_controllen = 0;
+ msg.msg_flags = 0;
+
+ iov.iov_len = handle->bufsize - offset;
+ iov.iov_base = bp + offset;
+
do {
/*
* Has "pcap_breakloop()" been called?
handle->break_loop = 0;
return -2;
}
- fromlen = sizeof(from);
- packet_len = recvfrom(
- handle->fd, bp + offset,
- handle->bufsize - offset, MSG_TRUNC,
- (struct sockaddr *) &from, &fromlen);
- } while (packet_len == -1 && errno == EINTR);
+
+ packet_len = recvmsg(handle->fd, &msg, MSG_TRUNC);
+ } while (packet_len == -1 && (errno == EINTR || errno == ENETDOWN));
/* Check if an error occured */
if (errno == EAGAIN)
return 0; /* no packet there */
else {
- snprintf(handle->errbuf, sizeof(handle->errbuf),
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"recvfrom: %s", pcap_strerror(errno));
return -1;
}
/* Fill in our own header data */
if (ioctl(handle->fd, SIOCGSTAMP, &pcap_header.ts) == -1) {
- snprintf(handle->errbuf, sizeof(handle->errbuf),
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"SIOCGSTAMP: %s", pcap_strerror(errno));
return -1;
}
return -1;
if (!filter) {
strncpy(handle->errbuf, "setfilter: No filter specified",
- sizeof(handle->errbuf));
+ PCAP_ERRBUF_SIZE);
return -1;
}
* We're not using PF_PACKET sockets, so we can't determine
* the direction of the packet.
*/
- snprintf(handle->errbuf, sizeof(handle->errbuf),
+ 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
return -1;
}
}
+#endif
/*
* Linux uses the ARP hardware type to identify the type of an
* 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 "live_open_new()",
+ * bridged onto it? ISDN is handled in "activate_new()",
* as we fall back on cooked mode there; are there any
* others?
*/
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;
+
default:
handle->linktype = -1;
break;
/* ===== Functions to interface to the newer kernels ================== */
/*
- * Try to open a packet socket using the new kernel interface.
- * Returns 0 on failure.
- * FIXME: 0 uses to mean success (Sebastian)
+ * 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
-live_open_new(pcap_t *handle, const char *device, int promisc,
- int to_ms, char *ebuf)
+activate_new(pcap_t *handle)
{
#ifdef HAVE_PF_PACKET_SOCKETS
int sock_fd = -1, arptype;
- int err;
- int fatal_err = 0;
+ int err = 0;
struct packet_mreq mr;
+ const char* device = handle->opt.source;
- /* One shot loop used for error handling - bail out with break */
-
- do {
- /*
- * Open a socket with protocol family packet. If a device is
- * given we try to open it in raw mode otherwise we use
- * the cooked interface.
- */
- sock_fd = device ?
- socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL))
- : socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_ALL));
-
- if (sock_fd == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE, "socket: %s",
- pcap_strerror(errno) );
- break;
- }
+ /*
+ * Open a socket with protocol family packet. If a device is
+ * given we try to open it in raw mode otherwise we use
+ * the cooked interface.
+ */
+ sock_fd = device ?
+ socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL))
+ : socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_ALL));
- /* It seems the kernel supports the new interface. */
- handle->md.sock_packet = 0;
+ if (sock_fd == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "socket: %s",
+ pcap_strerror(errno) );
+ return 0; /* try old mechanism */
+ }
- /*
- * 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", ebuf);
+ /* It seems the kernel supports the new interface. */
+ handle->md.sock_packet = 0;
- /*
- * Default value for offset to align link-layer payload
- * on a 4-byte boundary.
- */
- handle->offset = 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);
- /*
- * What kind of frames do we have to deal with? Fall back
- * to cooked mode if we have an unknown interface type.
- */
+ /*
+ * Default value for offset to align link-layer payload
+ * on a 4-byte boundary.
+ */
+ handle->offset = 0;
- if (device) {
- /* Assume for now we don't need cooked mode. */
- handle->md.cooked = 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 (device) {
+ /* Assume for now we don't need cooked mode. */
+ handle->md.cooked = 0;
- arptype = iface_get_arptype(sock_fd, device, ebuf);
- if (arptype == -1) {
- fatal_err = 1;
- break;
+ 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_wext(handle, sock_fd, device);
+ if (err < 0) {
+ /* Hard failure */
+ close(sock_fd);
+ return err;
}
- 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(ebuf, PCAP_ERRBUF_SIZE,
- "close: %s", pcap_strerror(errno));
- break;
- }
- sock_fd = socket(PF_PACKET, SOCK_DGRAM,
- htons(ETH_P_ALL));
- if (sock_fd == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "socket: %s", pcap_strerror(errno));
- break;
- }
- handle->md.cooked = 1;
-
+ if (err == 0) {
/*
- * Get rid of any link-layer type list
- * we allocated - this only supports cooked
- * capture.
+ * Nothing worked for turning monitor mode
+ * on.
*/
- 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(ebuf, 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. */
- 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, ebuf);
- if (handle->md.ifindex == -1)
- break;
-
- if ((err = iface_bind(sock_fd, handle->md.ifindex,
- ebuf)) < 0) {
- if (err == -2)
- fatal_err = 1;
- break;
+ close(sock_fd);
+ return PCAP_ERROR_RFMON_NOTSUP;
}
- } else {
+ }
+ 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))) {
/*
- * This is cooked mode.
+ * 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;
- handle->linktype = DLT_LINUX_SLL;
/*
- * We're not bound to a device.
- * XXX - true? Or true only if we're using
- * the "any" 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.
+ * Get rid of any link-layer type list
+ * we allocated - this only supports cooked
+ * capture.
*/
- handle->md.ifindex = -1;
+ 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 {
/*
- * 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.
+ * This is cooked mode.
*/
+ handle->md.cooked = 1;
+ handle->linktype = DLT_LINUX_SLL;
/*
- * Hmm, how can we set promiscuous mode on all interfaces?
- * I am not sure if that is possible at all.
+ * We're not bound to a device.
+ * XXX - true? Or true only if we're using
+ * the "any" 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;
+ }
- if (device && 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(ebuf, PCAP_ERRBUF_SIZE,
- "setsockopt: %s", pcap_strerror(errno));
- break;
- }
- }
-
- /* Save the socket FD in the pcap structure */
+ /*
+ * 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.
+ */
- handle->fd = sock_fd;
+ /*
+ * Hmm, how can we set promiscuous mode on all interfaces?
+ * I am not sure if that is possible at all.
+ */
- return 1;
+ if (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;
+ }
+ }
- } while(0);
+ /*
+ * 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;
- if (sock_fd != -1)
- close(sock_fd);
+ /* Save the socket FD in the pcap structure */
+ handle->fd = sock_fd;
- if (fatal_err) {
- /*
- * Get rid of any link-layer type list we allocated.
- */
- if (handle->dlt_list != NULL)
- free(handle->dlt_list);
- return -2;
- } else
- return 0;
+ return 1;
#else
strncpy(ebuf,
"New packet capturing interface not supported by build "
}
static int
-live_open_mmap(pcap_t* handle, char* errmsg)
+activate_mmap(pcap_t *handle)
{
#ifdef HAVE_PACKET_RING
- /* by default request 4M for the ring buffer */
- int ret = create_ring(handle, 4*1024*1024, errmsg);
+ int ret;
+
+ if (handle->opt.buffer_size == 0) {
+ /* by default request 2M for the ring buffer */
+ handle->opt.buffer_size = 2*1024*1024;
+ }
+ ret = create_ring(handle);
if (ret == 0)
return ret;
/* override some defaults and inherit the other fields from
- * open_live_new
+ * 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->close_op = pcap_close_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;
}
static int
-create_ring(pcap_t* handle, unsigned size, char* errmsg)
+create_ring(pcap_t *handle)
{
unsigned i, j, ringsize, frames_per_block;
struct tpacket_req req;
* The snap len should be carefully chosen to achive best
* performance */
req.tp_frame_size = TPACKET_ALIGN(handle->snapshot+TPACKET_HDRLEN);
- req.tp_frame_nr = size/req.tp_frame_size;
+ req.tp_frame_nr = handle->opt.buffer_size/req.tp_frame_size;
compute_ring_block(req.tp_frame_size, &req.tp_block_size, &frames_per_block);
req.tp_block_nr = req.tp_frame_nr / frames_per_block;
req.tp_block_nr = req.tp_frame_nr/frames_per_block;
goto retry;
}
- snprintf(errmsg, PCAP_ERRBUF_SIZE, "can't create rx ring on "
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "can't create rx ring on "
"packet socket %d: %d-%s", handle->fd, errno,
pcap_strerror(errno));
return 0;
handle->bp = mmap(0, ringsize, PROT_READ| PROT_WRITE, MAP_SHARED,
handle->fd, 0);
if (handle->bp == MAP_FAILED) {
- snprintf(errmsg, PCAP_ERRBUF_SIZE, "can't mmap rx ring: %d-%s",
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "can't mmap rx ring: %d-%s",
errno, pcap_strerror(errno));
/* clear the allocated ring on error*/
munmap(handle->bp, block_size * handle->cc / frames_per_block);
handle->bp = 0;
}
-
- /* if the header ring is allocated, clear it*/
- if (handle->buffer) {
- free(handle->buffer);
- handle->buffer = 0;
- }
}
static void
-pcap_close_linux_mmap( pcap_t *handle )
+pcap_cleanup_linux_mmap( pcap_t *handle )
{
destroy_ring(handle);
- pcap_close_linux(handle);
+ pcap_cleanup_linux(handle);
}
-int
+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);
}
-int
+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_open_live */
+ * preserve the timeout value provided with pcap_set_timeout */
if (nonblock) {
if (p->md.timeout > 0)
p->md.timeout = p->md.timeout*-1 - 1;
} while (ret < 0);
}
- /* negative values of max_packets are used to require all
- * packets available in the ring */
- while ((pkts < max_packets) || (max_packets <0)) {
+ /* non-positive values of max_packets are used to require all
+ * packets currently available in the ring */
+ while ((pkts < max_packets) || (max_packets <= 0)) {
int run_bpf;
struct sockaddr_ll *sll;
struct pcap_pkthdr pcaphdr;
if (thdr->tp_mac+thdr->tp_snaplen > handle->bufsize) {
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"corrupted frame on kernel ring mac "
- "offset %d + caplen %d > frame len %d\n",
+ "offset %d + caplen %d > frame len %d",
thdr->tp_mac, thdr->tp_snaplen, handle->bufsize);
return -1;
}
/* if required build in place the sll header*/
if (handle->md.cooked) {
- struct sll_header *hdrp = (struct sll_header *)((char *)bp - sizeof(struct sll_header));
+ struct sll_header *hdrp;
+
+ /*
+ * The kernel should have left us with enough
+ * space for an sll header; back up the packet
+ * data pointer into that space, as that'll be
+ * the beginning of the packet we pass to the
+ * callback.
+ */
+ bp -= SLL_HDR_LEN;
+ /*
+ * Let's make sure that's past the end of
+ * the tpacket header, i.e. >=
+ * ((u_char *)thdr + TPACKET_HDRLEN), so we
+ * don't step on the header when we construct
+ * the sll header.
+ */
+ if (bp < (u_char *)thdr + TPACKET_HDRLEN) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "cooked-mode frame doesn't have room for sll header");
+ return -1;
+ }
+
+ /*
+ * OK, that worked; construct the sll header.
+ */
+ hdrp = (struct sll_header *)bp;
hdrp->sll_pkttype = map_packet_type_to_sll_type(
sll->sll_pkttype);
hdrp->sll_hatype = htons(sll->sll_hatype);
/*
* Bind the socket associated with FD to the given device.
+ * Return 1 on success, 0 if we should try a SOCK_PACKET socket,
+ * or a PCAP_ERROR_ value on a hard error.
*/
static int
iface_bind(int fd, int ifindex, char *ebuf)
sll.sll_protocol = htons(ETH_P_ALL);
if (bind(fd, (struct sockaddr *) &sll, sizeof(sll)) == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "bind: %s", pcap_strerror(errno));
- return -1;
+ if (errno == ENETDOWN) {
+ /*
+ * Return a "network down" indication, so that
+ * the application can report that rather than
+ * saying we had a mysterious failure and
+ * suggest that they report a problem to the
+ * libpcap developers.
+ */
+ return PCAP_ERROR_IFACE_NOT_UP;
+ } else {
+ snprintf(ebuf, PCAP_ERRBUF_SIZE,
+ "bind: %s", pcap_strerror(errno));
+ return PCAP_ERROR;
+ }
}
/* Any pending errors, e.g., network is down? */
if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &errlen) == -1) {
snprintf(ebuf, PCAP_ERRBUF_SIZE,
"getsockopt: %s", pcap_strerror(errno));
- return -2;
+ return 0;
}
- if (err > 0) {
+ if (err == ENETDOWN) {
+ /*
+ * Return a "network down" indication, so that
+ * the application can report that rather than
+ * saying we had a mysterious failure and
+ * suggest that they report a problem to the
+ * libpcap developers.
+ */
+ return PCAP_ERROR_IFACE_NOT_UP;
+ } else if (err > 0) {
snprintf(ebuf, PCAP_ERRBUF_SIZE,
"bind: %s", pcap_strerror(err));
- return -2;
+ return 0;
}
- return 0;
+ return 1;
}
-#endif
-
-
-/* ===== Functions to interface to the older kernels ================== */
-
/*
- * With older kernels promiscuous mode is kind of interesting because we
- * have to reset the interface before exiting. The problem can't really
- * be solved without some daemon taking care of managing usage counts.
- * If we put the interface into promiscuous mode, we set a flag indicating
- * that we must take it out of that mode when the interface is closed,
- * and, when closing the interface, if that flag is set we take it out
- * of promiscuous mode.
+ * Check whether the device supports the Wireless Extensions.
+ * Returns 1 if it does, 0 if it doesn't, PCAP_ERROR_NO_SUCH_DEVICE
+ * if the device doesn't even exist.
*/
+static int
+has_wext(int sock_fd, const char *device, char *ebuf)
+{
+#ifdef IW_MODE_MONITOR
+ struct iwreq ireq;
+
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ if (ioctl(sock_fd, SIOCGIWNAME, &ireq) >= 0)
+ return 1; /* yes */
+ snprintf(ebuf, PCAP_ERRBUF_SIZE,
+ "%s: SIOCGIWPRIV: %s", device, pcap_strerror(errno));
+ if (errno == ENODEV)
+ return PCAP_ERROR_NO_SUCH_DEVICE;
+#endif
+ return 0;
+}
/*
- * List of pcaps for which we turned promiscuous mode on by hand.
- * If there are any such pcaps, we arrange to call "pcap_close_all()"
- * when we exit, and have it close all of them to turn promiscuous mode
- * off.
+ * Per me si va ne la citta dolente,
+ * Per me si va ne l'etterno dolore,
+ * ...
+ * Lasciate ogne speranza, voi ch'intrate.
*/
-static struct pcap *pcaps_to_close;
+typedef enum {
+ MONITOR_WEXT,
+ MONITOR_HOSTAP,
+ MONITOR_PRISM,
+ MONITOR_PRISM54,
+ MONITOR_ACX100,
+ MONITOR_RT2500,
+ MONITOR_RT2570,
+ MONITOR_RT73,
+ MONITOR_RTL8XXX
+} monitor_type;
/*
- * TRUE if we've already called "atexit()" to cause "pcap_close_all()" to
- * be called on exit.
+ * Use the Wireless Extensions, if we have them, to try to turn monitor mode
+ * on if it's not already on.
+ *
+ * Returns 1 on success, 0 if we don't support the Wireless Extensions
+ * on this device, or a PCAP_ERROR_ value if we do support them but
+ * we weren't able to turn monitor mode on.
*/
-static int did_atexit;
-
-static void pcap_close_all(void)
+static int
+enter_rfmon_mode_wext(pcap_t *handle, int sock_fd, const char *device)
{
- struct pcap *handle;
+#ifdef IW_MODE_MONITOR
+ /*
+ * XXX - at least some adapters require non-Wireless Extensions
+ * mechanisms to turn monitor mode on.
+ *
+ * Atheros cards might require that a separate "monitor virtual access
+ * point" be created, with later versions of the madwifi driver.
+ *
+ * Some Intel Centrino adapters might require private ioctls to get
+ * radio headers; the ipw2200 and ipw3945 drivers allow you to
+ * configure a separate "rtapN" interface to capture in monitor
+ * mode without preventing the adapter from operating normally.
+ *
+ * It would be Truly Wonderful if mac80211 and nl80211 cleaned this
+ * up, and if all drivers were converted to mac80211 drivers.
+ */
+ int err;
+ struct iwreq ireq;
+ struct iw_priv_args *priv;
+ monitor_type montype;
+ int i;
+ __u32 cmd;
+ int args[2];
+ int channel;
- while ((handle = pcaps_to_close) != NULL)
- pcap_close(handle);
-}
+ /*
+ * Does this device *support* the Wireless Extensions?
+ */
+ err = has_wext(sock_fd, device, handle->errbuf);
+ if (err <= 0)
+ return err; /* either it doesn't or the device doesn't even exist */
+ /*
+ * Try to get all the Wireless Extensions private ioctls
+ * supported by this device.
+ *
+ * First, get the size of the buffer we need, by supplying no
+ * buffer and a length of 0. If the device supports private
+ * ioctls, it should return E2BIG, with ireq.u.data.length set
+ * to the length we need. If it doesn't support them, it should
+ * return EOPNOTSUPP.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ ireq.u.data.pointer = args;
+ ireq.u.data.length = 0;
+ ireq.u.data.flags = 0;
+ if (ioctl(sock_fd, SIOCGIWPRIV, &ireq) != -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: SIOCGIWPRIV with a zero-length buffer didn't fail!",
+ device);
+ return PCAP_ERROR;
+ }
+ if (errno == EOPNOTSUPP) {
+ /*
+ * No private ioctls, so we assume that there's only one
+ * DLT_ for monitor mode.
+ */
+ return 0;
+ }
+ if (errno != E2BIG) {
+ /*
+ * Failed.
+ */
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: SIOCGIWPRIV: %s", device, pcap_strerror(errno));
+ return PCAP_ERROR;
+ }
+ priv = malloc(ireq.u.data.length * sizeof (struct iw_priv_args));
+ if (priv == NULL) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "malloc: %s", pcap_strerror(errno));
+ return PCAP_ERROR;
+ }
+ ireq.u.data.pointer = priv;
+ if (ioctl(sock_fd, SIOCGIWPRIV, &ireq) == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: SIOCGIWPRIV: %s", device, pcap_strerror(errno));
+ free(priv);
+ return PCAP_ERROR;
+ }
-static void pcap_close_linux( pcap_t *handle )
-{
- struct pcap *p, *prevp;
- struct ifreq ifr;
+ /*
+ * Look for private ioctls to turn monitor mode on or, if
+ * monitor mode is on, to set the header type.
+ */
+ montype = MONITOR_WEXT;
+ cmd = 0;
+ for (i = 0; i < ireq.u.data.length; i++) {
+ if (strcmp(priv[i].name, "monitor_type") == 0) {
+ /*
+ * Hostap driver, use this one.
+ * Set monitor mode first.
+ * You can set it to 0 to get DLT_IEEE80211,
+ * 1 to get DLT_PRISM, or 2 to get
+ * DLT_IEEE80211_RADIO_AVS.
+ */
+ if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
+ break;
+ if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
+ break;
+ if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
+ break;
+ montype = MONITOR_HOSTAP;
+ cmd = priv[i].cmd;
+ break;
+ }
+ if (strcmp(priv[i].name, "set_prismhdr") == 0) {
+ /*
+ * Prism54 driver, use this one.
+ * Set monitor mode first.
+ * You can set it to 2 to get DLT_IEEE80211
+ * or 3 or get DLT_PRISM.
+ */
+ if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
+ break;
+ if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
+ break;
+ if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
+ break;
+ montype = MONITOR_PRISM54;
+ cmd = priv[i].cmd;
+ break;
+ }
+ if (strcmp(priv[i].name, "forceprismheader") == 0) {
+ /*
+ * RT2570 driver, use this one.
+ * Do this after turning monitor mode on.
+ * You can set it to 1 to get DLT_PRISM or 2
+ * to get DLT_IEEE80211.
+ */
+ if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
+ break;
+ if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
+ break;
+ if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
+ break;
+ montype = MONITOR_RT2570;
+ cmd = priv[i].cmd;
+ break;
+ }
+ if (strcmp(priv[i].name, "forceprism") == 0) {
+ /*
+ * RT73 driver, use this one.
+ * Do this after turning monitor mode on.
+ * Its argument is a *string*; you can
+ * set it to "1" to get DLT_PRISM or "2"
+ * to get DLT_IEEE80211.
+ */
+ if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_CHAR)
+ break;
+ if (priv[i].set_args & IW_PRIV_SIZE_FIXED)
+ break;
+ montype = MONITOR_RT73;
+ cmd = priv[i].cmd;
+ break;
+ }
+ if (strcmp(priv[i].name, "prismhdr") == 0) {
+ /*
+ * One of the RTL8xxx drivers, use this one.
+ * It can only be done after monitor mode
+ * has been turned on. You can set it to 1
+ * to get DLT_PRISM or 0 to get DLT_IEEE80211.
+ */
+ if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
+ break;
+ if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
+ break;
+ if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
+ break;
+ montype = MONITOR_RTL8XXX;
+ cmd = priv[i].cmd;
+ break;
+ }
+ if (strcmp(priv[i].name, "rfmontx") == 0) {
+ /*
+ * RT2500 or RT61 driver, use this one.
+ * It has one one-byte parameter; set
+ * u.data.length to 1 and u.data.pointer to
+ * point to the parameter.
+ * It doesn't itself turn monitor mode on.
+ * You can set it to 1 to allow transmitting
+ * in monitor mode(?) and get DLT_IEEE80211,
+ * or set it to 0 to disallow transmitting in
+ * monitor mode(?) and get DLT_PRISM.
+ */
+ if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
+ break;
+ if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 2)
+ break;
+ montype = MONITOR_RT2500;
+ cmd = priv[i].cmd;
+ break;
+ }
+ if (strcmp(priv[i].name, "monitor") == 0) {
+ /*
+ * Either ACX100 or hostap, use this one.
+ * It turns monitor mode on.
+ * If it takes two arguments, it's ACX100;
+ * the first argument is 1 for DLT_PRISM
+ * or 2 for DLT_IEEE80211, and the second
+ * argument is the channel on which to
+ * run. If it takes one argument, it's
+ * HostAP, and the argument is 2 for
+ * DLT_IEEE80211 and 3 for DLT_PRISM.
+ *
+ * If we see this, we don't quit, as this
+ * might be a version of the hostap driver
+ * that also supports "monitor_type".
+ */
+ if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
+ break;
+ if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
+ break;
+ switch (priv[i].set_args & IW_PRIV_SIZE_MASK) {
- if (handle->md.clear_promisc) {
+ case 1:
+ montype = MONITOR_PRISM;
+ cmd = priv[i].cmd;
+ break;
+
+ case 2:
+ montype = MONITOR_ACX100;
+ cmd = priv[i].cmd;
+ break;
+
+ default:
+ break;
+ }
+ }
+ }
+ free(priv);
+
+ /*
+ * XXX - ipw3945? islism?
+ */
+
+ /*
+ * Get the old mode.
+ */
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ if (ioctl(sock_fd, SIOCGIWMODE, &ireq) == -1) {
+ /*
+ * We probably won't be able to set the mode, either.
+ */
+ return PCAP_ERROR_RFMON_NOTSUP;
+ }
+
+ /*
+ * Is it currently in monitor mode?
+ */
+ if (ireq.u.mode == IW_MODE_MONITOR) {
/*
- * We put the interface into promiscuous mode; take
- * it out of promiscuous mode.
+ * Yes. Just leave things as they are.
+ * We don't offer multiple link-layer types, as
+ * changing the link-layer type out from under
+ * somebody else capturing in monitor mode would
+ * be considered rude.
+ */
+ return 1;
+ }
+ /*
+ * No. We have to put the adapter into rfmon mode.
+ */
+
+ /*
+ * If we haven't already done so, arrange to have
+ * "pcap_close_all()" called when we exit.
+ */
+ if (!pcap_do_addexit(handle)) {
+ /*
+ * "atexit()" failed; don't put the interface
+ * in rfmon mode, just give up.
+ */
+ return PCAP_ERROR_RFMON_NOTSUP;
+ }
+
+ /*
+ * Save the old mode.
+ */
+ handle->md.oldmode = ireq.u.mode;
+
+ /*
+ * Put the adapter in rfmon mode. How we do this depends
+ * on whether we have a special private ioctl or not.
+ */
+ if (montype == MONITOR_PRISM) {
+ /*
+ * We have the "monitor" private ioctl, but none of
+ * the other private ioctls. Use this, and select
+ * the Prism header.
*
- * 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.
+ * If it fails, just fall back on SIOCSIWMODE.
*/
- 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));
- }
- }
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ ireq.u.data.length = 1; /* 1 argument */
+ args[0] = 3; /* request Prism header */
+ memcpy(ireq.u.name, args, IFNAMSIZ);
+ if (ioctl(sock_fd, cmd, &ireq) != -1) {
+ /*
+ * Success.
+ * Note that we have to put the old mode back
+ * when we close the device.
+ */
+ handle->md.must_clear |= MUST_CLEAR_RFMON;
+
+ /*
+ * Add this to the list of pcaps to close
+ * when we exit.
+ */
+ pcap_add_to_pcaps_to_close(handle);
+
+ return 1;
}
/*
- * Take this pcap out of the list of pcaps for which we
- * have to take the interface out of promiscuous mode.
+ * Failure. Fall back on SIOCSIWMODE.
*/
- for (p = pcaps_to_close, prevp = NULL; p != NULL;
- prevp = p, p = p->md.next) {
- if (p == handle) {
- /*
- * Found it. Remove it from the list.
- */
- if (prevp == NULL) {
- /*
- * It was at the head of the list.
- */
- pcaps_to_close = p->md.next;
- } else {
- /*
- * It was in the middle of the list.
- */
- prevp->md.next = p->md.next;
- }
- break;
- }
+ }
+
+ /*
+ * First, turn monitor mode on.
+ */
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ ireq.u.mode = IW_MODE_MONITOR;
+ if (ioctl(sock_fd, SIOCSIWMODE, &ireq) == -1) {
+ /*
+ * Scientist, you've failed.
+ */
+ return PCAP_ERROR_RFMON_NOTSUP;
+ }
+
+ /*
+ * Now select the appropriate radio header.
+ */
+ switch (montype) {
+
+ case MONITOR_WEXT:
+ /*
+ * We don't have any private ioctl to set the header.
+ */
+ break;
+
+ case MONITOR_HOSTAP:
+ /*
+ * Select the AVS header if we can, otherwise
+ * select the Prism header.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ args[0] = 2; /* request AVS header */
+ memcpy(ireq.u.name, args, sizeof (int));
+ if (ioctl(sock_fd, cmd, &ireq) == -1) {
+ /*
+ * Failure - try the Prism header.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ args[0] = 1; /* request Prism header */
+ memcpy(ireq.u.name, args, sizeof (int));
+ ioctl(sock_fd, cmd, &ireq);
}
+ break;
+
+ case MONITOR_PRISM:
+ /*
+ * The private ioctl failed.
+ */
+ break;
+
+ case MONITOR_PRISM54:
+ /*
+ * Select the Prism header.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ args[0] = 3; /* request Prism header */
+ memcpy(ireq.u.name, args, sizeof (int));
+ ioctl(sock_fd, cmd, &ireq);
+ break;
+
+ case MONITOR_ACX100:
+ /*
+ * Get the current channel.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ if (ioctl(sock_fd, SIOCGIWFREQ, &ireq) == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "%s: SIOCGIWFREQ: %s", device,
+ pcap_strerror(errno));
+ return PCAP_ERROR;
+ }
+ channel = ireq.u.freq.m;
+
+ /*
+ * Select the Prism header, and set the channel to the
+ * current value.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ args[0] = 1; /* request Prism header */
+ args[1] = channel; /* set channel */
+ memcpy(ireq.u.name, args, 2*sizeof (int));
+ ioctl(sock_fd, cmd, &ireq);
+ break;
+
+ case MONITOR_RT2500:
+ /*
+ * Disallow transmission - that turns on the
+ * Prism header.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ args[0] = 0; /* disallow transmitting */
+ memcpy(ireq.u.name, args, sizeof (int));
+ ioctl(sock_fd, cmd, &ireq);
+ break;
+
+ case MONITOR_RT2570:
+ /*
+ * Force the Prism header.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ args[0] = 1; /* request Prism header */
+ memcpy(ireq.u.name, args, sizeof (int));
+ ioctl(sock_fd, cmd, &ireq);
+ break;
+
+ case MONITOR_RT73:
+ /*
+ * Force the Prism header.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ ireq.u.data.length = 1; /* 1 argument */
+ ireq.u.data.pointer = "1";
+ ireq.u.data.flags = 0;
+ ioctl(sock_fd, cmd, &ireq);
+ break;
+
+ case MONITOR_RTL8XXX:
+ /*
+ * Force the Prism header.
+ */
+ memset(&ireq, 0, sizeof ireq);
+ strncpy(ireq.ifr_ifrn.ifrn_name, device,
+ sizeof ireq.ifr_ifrn.ifrn_name);
+ ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
+ args[0] = 1; /* request Prism header */
+ memcpy(ireq.u.name, args, sizeof (int));
+ ioctl(sock_fd, cmd, &ireq);
+ break;
}
- if (handle->md.device != NULL)
- free(handle->md.device);
- handle->md.device = NULL;
- pcap_close_common(handle);
+ /*
+ * Note that we have to put the old mode back when we
+ * close the device.
+ */
+ handle->md.must_clear |= MUST_CLEAR_RFMON;
+
+ /*
+ * Add this to the list of pcaps to close when we exit.
+ */
+ pcap_add_to_pcaps_to_close(handle);
+
+ return 1;
+#else
+ /*
+ * We don't have the Wireless Extensions available, so we can't
+ * do monitor mode.
+ */
+ return 0;
+#endif
}
+#endif /* HAVE_PF_PACKET_SOCKETS */
+
+/* ===== Functions to interface to the older kernels ================== */
+
/*
- * Try to open a packet socket using the old kernel interface.
- * Returns 0 on failure.
- * FIXME: 0 uses to mean success (Sebastian)
+ * Try to open a packet socket using the old kernel interface.
+ * Returns 1 on success and a PCAP_ERROR_ value on an error.
*/
static int
-live_open_old(pcap_t *handle, const char *device, int promisc,
- int to_ms, char *ebuf)
+activate_old(pcap_t *handle)
{
int arptype;
struct ifreq ifr;
+ const char *device = handle->opt.source;
+ struct utsname utsname;
+ int mtu;
- do {
- /* Open the socket */
+ /* Open the socket */
- handle->fd = socket(PF_INET, SOCK_PACKET, htons(ETH_P_ALL));
- if (handle->fd == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "socket: %s", pcap_strerror(errno));
- break;
- }
+ handle->fd = socket(PF_INET, SOCK_PACKET, htons(ETH_P_ALL));
+ if (handle->fd == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "socket: %s", pcap_strerror(errno));
+ return PCAP_ERROR_PERM_DENIED;
+ }
- /* It worked - we are using the old interface */
- handle->md.sock_packet = 1;
+ /* It worked - we are using the old interface */
+ handle->md.sock_packet = 1;
- /* ...which means we get the link-layer header. */
- handle->md.cooked = 0;
+ /* ...which means we get the link-layer header. */
+ handle->md.cooked = 0;
- /* Bind to the given device */
+ /* Bind to the given device */
- if (!device) {
- strncpy(ebuf, "pcap_open_live: The \"any\" device isn't supported on 2.0[.x]-kernel systems",
- PCAP_ERRBUF_SIZE);
- break;
- }
- if (iface_bind_old(handle->fd, device, ebuf) == -1)
- break;
+ if (!device) {
+ strncpy(handle->errbuf, "pcap_activate: The \"any\" device isn't supported on 2.0[.x]-kernel systems",
+ PCAP_ERRBUF_SIZE);
+ return PCAP_ERROR;
+ }
+ if (iface_bind_old(handle->fd, device, handle->errbuf) == -1)
+ return PCAP_ERROR;
- /*
- * Try to get the link-layer type.
- */
- arptype = iface_get_arptype(handle->fd, device, ebuf);
- if (arptype == -1)
- break;
+ /*
+ * Try to get the link-layer type.
+ */
+ arptype = iface_get_arptype(handle->fd, device, handle->errbuf);
+ if (arptype < 0)
+ return PCAP_ERROR;
- /*
- * Try to find the DLT_ type corresponding to that
- * link-layer type.
- */
- map_arphrd_to_dlt(handle, arptype, 0);
- if (handle->linktype == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "unknown arptype %d", arptype);
- break;
- }
+ /*
+ * Try to find the DLT_ type corresponding to that
+ * link-layer type.
+ */
+ map_arphrd_to_dlt(handle, arptype, 0);
+ if (handle->linktype == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "unknown arptype %d", arptype);
+ return PCAP_ERROR;
+ }
- /* Go to promisc mode if requested */
+ /* Go to promisc mode if requested */
- if (promisc) {
- memset(&ifr, 0, sizeof(ifr));
- strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
- if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "SIOCGIFFLAGS: %s", pcap_strerror(errno));
- break;
- }
- if ((ifr.ifr_flags & IFF_PROMISC) == 0) {
- /*
- * Promiscuous mode isn't currently on,
- * so turn it on, and remember that
- * we should turn it off when the
- * pcap_t is closed.
- */
+ if (handle->opt.promisc) {
+ memset(&ifr, 0, sizeof(ifr));
+ strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
+ if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "SIOCGIFFLAGS: %s", pcap_strerror(errno));
+ return PCAP_ERROR;
+ }
+ if ((ifr.ifr_flags & IFF_PROMISC) == 0) {
+ /*
+ * Promiscuous mode isn't currently on,
+ * so turn it on, and remember that
+ * we should turn it off when the
+ * pcap_t is closed.
+ */
+ /*
+ * If we haven't already done so, arrange
+ * to have "pcap_close_all()" called when
+ * we exit.
+ */
+ if (!pcap_do_addexit(handle)) {
/*
- * If we haven't already done so, arrange
- * to have "pcap_close_all()" called when
- * we exit.
+ * "atexit()" failed; don't put
+ * the interface in promiscuous
+ * mode, just give up.
*/
- if (!did_atexit) {
- if (atexit(pcap_close_all) == -1) {
- /*
- * "atexit()" failed; don't
- * put the interface in
- * promiscuous mode, just
- * give up.
- */
- strncpy(ebuf, "atexit failed",
- PCAP_ERRBUF_SIZE);
- break;
- }
- did_atexit = 1;
- }
-
- ifr.ifr_flags |= IFF_PROMISC;
- if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "SIOCSIFFLAGS: %s",
- pcap_strerror(errno));
- break;
- }
- handle->md.clear_promisc = 1;
+ return PCAP_ERROR;
+ }
- /*
- * Add this to the list of pcaps
- * to close when we exit.
- */
- handle->md.next = pcaps_to_close;
- pcaps_to_close = handle;
+ ifr.ifr_flags |= IFF_PROMISC;
+ if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "SIOCSIFFLAGS: %s",
+ pcap_strerror(errno));
+ return PCAP_ERROR;
}
+ handle->md.must_clear |= MUST_CLEAR_PROMISC;
+
+ /*
+ * Add this to the list of pcaps
+ * to close when we exit.
+ */
+ pcap_add_to_pcaps_to_close(handle);
}
+ }
+ /*
+ * Compute the buffer size.
+ *
+ * We're using SOCK_PACKET, so this might be a 2.0[.x]
+ * kernel, and might require special handling - check.
+ */
+ if (uname(&utsname) < 0 ||
+ strncmp(utsname.release, "2.0", 3) == 0) {
+ /*
+ * Either we couldn't find out what kernel release
+ * this is, or it's a 2.0[.x] kernel.
+ *
+ * In the 2.0[.x] kernel, a "recvfrom()" on
+ * a SOCK_PACKET socket, with MSG_TRUNC set, will
+ * return the number of bytes read, so if we pass
+ * a length based on the snapshot length, it'll
+ * return the number of bytes from the packet
+ * copied to userland, not the actual length
+ * of the packet.
+ *
+ * This means that, for example, the IP dissector
+ * in tcpdump will get handed a packet length less
+ * than the length in the IP header, and will
+ * complain about "truncated-ip".
+ *
+ * So we don't bother trying to copy from the
+ * kernel only the bytes in which we're interested,
+ * but instead copy them all, just as the older
+ * versions of libpcap for Linux did.
+ *
+ * The buffer therefore needs to be big enough to
+ * hold the largest packet we can get from this
+ * device. Unfortunately, we can't get the MRU
+ * of the network; we can only get the MTU. The
+ * MTU may be too small, in which case a packet larger
+ * than the buffer size will be truncated *and* we
+ * won't get the actual packet size.
+ *
+ * However, if the snapshot length is larger than
+ * the buffer size based on the MTU, we use the
+ * snapshot length as the buffer size, instead;
+ * this means that with a sufficiently large snapshot
+ * length we won't artificially truncate packets
+ * to the MTU-based size.
+ *
+ * This mess just one of many problems with packet
+ * capture on 2.0[.x] kernels; you really want a
+ * 2.2[.x] or later kernel if you want packet capture
+ * to work well.
+ */
+ mtu = iface_get_mtu(handle->fd, device, handle->errbuf);
+ if (mtu == -1)
+ return PCAP_ERROR;
+ handle->bufsize = MAX_LINKHEADER_SIZE + mtu;
+ if (handle->bufsize < handle->snapshot)
+ handle->bufsize = handle->snapshot;
+ } else {
/*
- * Default value for offset to align link-layer payload
- * on a 4-byte boundary.
+ * This is a 2.2[.x] or later kernel.
+ *
+ * We can safely pass "recvfrom()" a byte count
+ * based on the snapshot length.
*/
- handle->offset = 0;
-
- return 1;
+ handle->bufsize = handle->snapshot;
+ }
- } while (0);
+ /*
+ * Default value for offset to align link-layer payload
+ * on a 4-byte boundary.
+ */
+ handle->offset = 0;
- pcap_close_linux(handle);
- return 0;
+ return 1;
}
/*
if (ioctl(fd, SIOCGIFHWADDR, &ifr) == -1) {
snprintf(ebuf, PCAP_ERRBUF_SIZE,
"SIOCGIFHWADDR: %s", pcap_strerror(errno));
- return -1;
+ if (errno == ENODEV) {
+ /*
+ * No such device.
+ */
+ return PCAP_ERROR_NO_SUCH_DEVICE;
+ }
+ return PCAP_ERROR;
}
return ifr.ifr_hwaddr.sa_family;
len = handle->fcode.bf_len;
f = (struct bpf_insn *)malloc(prog_size);
if (f == NULL) {
- snprintf(handle->errbuf, sizeof(handle->errbuf),
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"malloc: %s", pcap_strerror(errno));
return -1;
}
if (save_errno != EAGAIN) {
/* Fatal error */
reset_kernel_filter(handle);
- snprintf(handle->errbuf, sizeof(handle->errbuf),
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"recv: %s", pcap_strerror(save_errno));
return -2;
}
projects / libpcap / blobdiff