diff options
Diffstat (limited to 'pcap-linux.c')
| -rw-r--r-- | pcap-linux.c | 2511 |
1 files changed, 1945 insertions, 566 deletions
diff --git a/pcap-linux.c b/pcap-linux.c index e9db010d3238..8161af019ed9 100644 --- a/pcap-linux.c +++ b/pcap-linux.c @@ -23,11 +23,18 @@ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. + * + * Modifications: Added PACKET_MMAP support + * Paolo Abeni <paolo.abeni@email.it> + * + * based on previous works of: + * Simon Patarin <patarin@cs.unibo.it> + * Phil Wood <cpw@lanl.gov> */ #ifndef lint static const char rcsid[] _U_ = - "@(#) $Header: /tcpdump/master/libpcap/pcap-linux.c,v 1.110.2.14 2006/10/12 17:26:58 guy Exp $ (LBL)"; + "@(#) $Header: /tcpdump/master/libpcap/pcap-linux.c,v 1.129.2.29 2008-10-28 00:50:39 guy Exp $ (LBL)"; #endif /* @@ -77,17 +84,6 @@ static const char rcsid[] _U_ = #include "config.h" #endif -#include "pcap-int.h" -#include "sll.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 */ - #include <errno.h> #include <stdlib.h> #include <unistd.h> @@ -96,10 +92,39 @@ static const char rcsid[] _U_ = #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/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 PCAP_SUPPORT_USB +#include "pcap-usb-linux.h" +#endif + +#ifdef PCAP_SUPPORT_BT +#include "pcap-bt-linux.h" +#endif /* * If PF_PACKET is defined, we can use {SOCK_RAW,SOCK_DGRAM}/PF_PACKET @@ -141,7 +166,23 @@ static const char rcsid[] _U_ = */ # 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 @@ -149,7 +190,7 @@ static const char rcsid[] _U_ = #include <linux/filter.h> #endif -#ifndef __GLIBC__ +#ifndef HAVE_SOCKLEN_T typedef int socklen_t; #endif @@ -185,18 +226,43 @@ typedef int socklen_t; #define BIGGER_THAN_ALL_MTUS (64*1024) /* - * Prototypes for internal functions + * Prototypes for internal functions and methods. */ static void map_arphrd_to_dlt(pcap_t *, int, int); -static int live_open_old(pcap_t *, const char *, int, int, char *); -static int live_open_new(pcap_t *, const char *, int, int, char *); +#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 *); +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 *); + +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); +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); +#endif /* * Wrap some ioctl calls @@ -208,6 +274,9 @@ 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); +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); @@ -223,52 +292,230 @@ static struct sock_fprog total_fcode = { 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 */ - /* Allocate a handle for this session. */ +#ifdef PCAP_SUPPORT_BT + if (strstr(device, "bluetooth")) { + return bt_create(device, ebuf); + } +#endif - handle = malloc(sizeof(*handle)); - if (handle == NULL) { - snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s", - pcap_strerror(errno)); +#ifdef PCAP_SUPPORT_USB + if (strstr(device, "usb")) { + 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; + 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; } - /* Initialize some components of the pcap structure. */ +#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; + } - memset(handle, 0, sizeof(*handle)); - handle->snapshot = snaplen; - handle->md.timeout = to_ms; + /* + * 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); +} + +/* + * 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; + + 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; /* * NULL and "any" are special devices which give us the hint to @@ -277,21 +524,21 @@ pcap_open_live(const char *device, int snaplen, int promisc, int to_ms, 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; } /* @@ -304,118 +551,50 @@ pcap_open_live(const char *device, int snaplen, int promisc, int to_ms, * trying both methods with the newer method preferred. */ - if ((err = live_open_new(handle, device, promisc, to_ms, ebuf)) == 1) - live_open_ok = 1; - else if (err == 0) { + 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 (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)) { + if (handle->opt.buffer_size != 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. + * Set the socket buffer size to the specified value. */ - mtu = iface_get_mtu(handle->fd, device, ebuf); - if (mtu == -1) { - pcap_close_linux(handle); - free(handle); - return NULL; - } - handle->bufsize = MAX_LINKHEADER_SIZE + mtu; - if (handle->bufsize < handle->snapshot) - handle->bufsize = handle->snapshot; - } else { - /* - * This is a 2.2[.x] or later kernel (we know that - * either because we're not using a SOCK_PACKET - * socket - PF_PACKET is supported only in 2.2 - * and later kernels - or because we checked the - * kernel version). - * - * We can safely pass "recvfrom()" a byte count - * based on the snapshot length. - * - * 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; + 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; } /* @@ -424,17 +603,11 @@ pcap_open_live(const char *device, int snaplen, int promisc, int to_ms, */ handle->selectable_fd = handle->fd; - handle->read_op = pcap_read_linux; - 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->stats_op = pcap_stats_linux; - handle->close_op = pcap_close_linux; + return status; - return handle; +fail: + pcap_cleanup_linux(handle); + return status; } /* @@ -468,7 +641,17 @@ pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata) #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; @@ -489,9 +672,36 @@ pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata) 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; + +#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? @@ -505,12 +715,17 @@ pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata) handle->break_loop = 0; return -2; } + +#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); - } while (packet_len == -1 && errno == EINTR); +#endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */ + } while (packet_len == -1 && (errno == EINTR || errno == ENETDOWN)); /* Check if an error occured */ @@ -518,7 +733,7 @@ pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata) 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; } @@ -586,51 +801,46 @@ pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata) 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; + } - /* - * Map the PACKET_ value to a LINUX_SLL_ value; we - * want the same numerical value to be used in - * the link-layer header even if the numerical values - * for the PACKET_ #defines change, so that programs - * that look at the packet type field will always be - * able to handle DLT_LINUX_SLL captures. - */ - switch (from.sll_pkttype) { +#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; - case PACKET_HOST: - hdrp->sll_pkttype = htons(LINUX_SLL_HOST); - break; + if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct tpacket_auxdata)) || + cmsg->cmsg_level != SOL_PACKET || + cmsg->cmsg_type != PACKET_AUXDATA) + continue; - case PACKET_BROADCAST: - hdrp->sll_pkttype = htons(LINUX_SLL_BROADCAST); - break; + aux = (struct tpacket_auxdata *)CMSG_DATA(cmsg); + if (aux->tp_vlan_tci == 0) + continue; - case PACKET_MULTICAST: - hdrp->sll_pkttype = htons(LINUX_SLL_MULTICAST); + len = packet_len > iov.iov_len ? iov.iov_len : packet_len; + if (len < 2 * ETH_ALEN) break; - case PACKET_OTHERHOST: - hdrp->sll_pkttype = htons(LINUX_SLL_OTHERHOST); - break; + bp -= VLAN_TAG_LEN; + memmove(bp, bp + VLAN_TAG_LEN, 2 * ETH_ALEN); - case PACKET_OUTGOING: - hdrp->sll_pkttype = htons(LINUX_SLL_OUTGOING); - break; + tag = (struct vlan_tag *)(bp + 2 * ETH_ALEN); + tag->vlan_tpid = htons(ETH_P_8021Q); + tag->vlan_tci = htons(aux->tp_vlan_tci); - default: - hdrp->sll_pkttype = -1; - break; - } - - 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; + packet_len += VLAN_TAG_LEN; } -#endif +#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 @@ -681,7 +891,7 @@ pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata) /* 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; } @@ -915,6 +1125,16 @@ pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf) return (-1); #endif /* HAVE_SEPTEL_API */ +#ifdef PCAP_SUPPORT_BT + if (bt_platform_finddevs(alldevsp, errbuf) < 0) + return (-1); +#endif + +#ifdef PCAP_SUPPORT_USB + if (usb_platform_finddevs(alldevsp, errbuf) < 0) + return (-1); +#endif + return (0); } @@ -934,7 +1154,7 @@ pcap_setfilter_linux(pcap_t *handle, struct bpf_program *filter) return -1; if (!filter) { strncpy(handle->errbuf, "setfilter: No filter specified", - sizeof(handle->errbuf)); + PCAP_ERRBUF_SIZE); return -1; } @@ -1072,11 +1292,47 @@ pcap_setdirection_linux(pcap_t *handle, pcap_direction_t d) * 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 + * 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 @@ -1113,7 +1369,7 @@ static void map_arphrd_to_dlt(pcap_t *handle, int arptype, int cooked_ok) * 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? */ @@ -1139,7 +1395,7 @@ static void map_arphrd_to_dlt(pcap_t *handle, int arptype, int cooked_ok) break; case ARPHRD_AX25: - handle->linktype = DLT_AX25; + handle->linktype = DLT_AX25_KISS; break; case ARPHRD_PRONET: @@ -1371,6 +1627,17 @@ static void map_arphrd_to_dlt(pcap_t *handle, int arptype, int cooked_ok) 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; @@ -1380,218 +1647,265 @@ static void map_arphrd_to_dlt(pcap_t *handle, int arptype, int cooked_ok) /* ===== 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 sock_fd = -1, arptype, val; + 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))) { + if (err == 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. + * Nothing worked for turning monitor mode + * on. */ - 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; + close(sock_fd); + return PCAP_ERROR_RFMON_NOTSUP; + } + } + 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) { /* - * Get rid of any link-layer type list - * we allocated - this only supports cooked - * capture. + * Warn that we're falling back on + * cooked mode; we may want to + * update "map_arphrd_to_dlt()" + * to handle the new type. */ - 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; + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "arptype %d not " + "supported by libpcap - " + "falling back to cooked " + "socket", + arptype); } - 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; - } - } else { /* - * This is cooked mode. + * IrDA capture is not a real "cooked" capture, + * it's IrLAP frames, not IP packets. The + * same applies to LAPD capture. */ - handle->md.cooked = 1; - handle->linktype = DLT_LINUX_SLL; + if (handle->linktype != DLT_LINUX_IRDA && + handle->linktype != DLT_LINUX_LAPD) + 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. - */ - handle->md.ifindex = -1; + 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; - } - } + /* + * 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. + */ - /* Save the socket FD in the pcap structure */ + /* + * Hmm, how can we set promiscuous mode on all interfaces? + * I am not sure if that is possible at all. + */ - handle->fd = sock_fd; + 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; + } + } - return 1; + /* 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 */ - } 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 " @@ -1600,6 +1914,488 @@ live_open_new(pcap_t *handle, const char *device, int promisc, #endif } +static int +activate_mmap(pcap_t *handle) +{ +#ifdef HAVE_PACKET_RING + int ret; + + 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 == 0) + return ret; + ret = create_ring(handle); + if (ret == 0) + return ret; + + /* 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->selectable_fd = handle->fd; + return 1; +#else /* HAVE_PACKET_RING */ + return 0; +#endif /* HAVE_PACKET_RING */ +} + +#ifdef HAVE_PACKET_RING +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; + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "can't get TPACKET_V2 header len on socket %d: %d-%s", + handle->fd, errno, pcap_strerror(errno)); + return 0; + } + 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 socket %d: %d-%s", + handle->fd, errno, pcap_strerror(errno)); + return 0; + } + 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 socket %d: %d-%s", + handle->fd, errno, pcap_strerror(errno)); + return 0; + } + +#endif /* HAVE_TPACKET2 */ + return 1; +} + +static void +compute_ring_block(int frame_size, unsigned *block_size, unsigned *frames_per_block) +{ + /* 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. */ + *block_size = getpagesize(); + while (*block_size < frame_size) + *block_size <<= 1; + + *frames_per_block = *block_size/frame_size; +} + +static int +create_ring(pcap_t *handle) +{ + unsigned i, j, ringsize, frames_per_block; + struct tpacket_req req; + + /* 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_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_frame_nr is requested to match frames_per_block*req.tp_block_nr */ + req.tp_frame_nr = req.tp_block_nr * frames_per_block; + + /* ask the kernel to create the ring */ +retry: + if (setsockopt(handle->fd, SOL_PACKET, PACKET_RX_RING, + (void *) &req, sizeof(req))) { + /* try to reduce requested ring size to prevent memory failure */ + if ((errno == ENOMEM) && (req.tp_block_nr > 1)) { + req.tp_frame_nr >>= 1; + req.tp_block_nr = req.tp_frame_nr/frames_per_block; + goto retry; + } + 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; + } + + /* memory map the rx ring */ + ringsize = req.tp_block_nr * req.tp_block_size; + handle->bp = mmap(0, ringsize, PROT_READ| PROT_WRITE, MAP_SHARED, + handle->fd, 0); + if (handle->bp == MAP_FAILED) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "can't mmap rx ring: %d-%s", + errno, pcap_strerror(errno)); + + /* clear the allocated ring on error*/ + destroy_ring(handle); + return 0; + } + + /* 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) { + destroy_ring(handle); + return 0; + } + + /* fill the header ring with proper frame ptr*/ + handle->offset = 0; + for (i=0; i<req.tp_block_nr; ++i) { + void *base = &handle->bp[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->bp) { + /* need to re-compute the ring size */ + unsigned frames_per_block, block_size; + compute_ring_block(handle->bufsize, &block_size, &frames_per_block); + + /* do not perform sanity check here: we can't recover any error */ + munmap(handle->bp, block_size * handle->cc / frames_per_block); + handle->bp = 0; + } +} + +static void +pcap_cleanup_linux_mmap( pcap_t *handle ) +{ + destroy_ring(handle); + 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) + p->md.timeout = p->md.timeout*-1 - 1; + } else + if (p->md.timeout < 0) + 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; +} + +static int +pcap_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, + u_char *user) +{ + int pkts = 0; + + /* wait for frames availability.*/ + if ((handle->md.timeout >= 0) && + !pcap_get_ring_frame(handle, TP_STATUS_USER)) { + struct pollfd pollinfo; + int ret; + + pollinfo.fd = handle->fd; + pollinfo.events = POLLIN; + + do { + /* poll() requires a negative timeout to wait forever */ + ret = poll(&pollinfo, 1, (handle->md.timeout > 0)? + handle->md.timeout: -1); + if ((ret < 0) && (errno != EINTR)) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "can't poll on packet socket fd %d: %d-%s", + handle->fd, errno, pcap_strerror(errno)); + return -1; + } + /* check for break loop condition on interrupted syscall*/ + if (handle->break_loop) { + handle->break_loop = 0; + return -2; + } + } while (ret < 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; + unsigned char *bp; + union thdr h; + unsigned int tp_len; + unsigned int tp_mac; + unsigned int tp_snaplen; + unsigned int tp_sec; + unsigned int tp_usec; + + h.raw = pcap_get_ring_frame(handle, TP_STATUS_USER); + if (!h.raw) + break; + + switch (handle->md.tp_version) { + case TPACKET_V1: + tp_len = h.h1->tp_len; + tp_mac = h.h1->tp_mac; + tp_snaplen = h.h1->tp_snaplen; + tp_sec = h.h1->tp_sec; + tp_usec = h.h1->tp_usec; + break; +#ifdef HAVE_TPACKET2 + case TPACKET_V2: + tp_len = h.h2->tp_len; + tp_mac = h.h2->tp_mac; + tp_snaplen = h.h2->tp_snaplen; + tp_sec = h.h2->tp_sec; + tp_usec = h.h2->tp_nsec / 1000; + break; +#endif + default: + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "unsupported tpacket version %d", + handle->md.tp_version); + return -1; + } + /* perform sanity check on internal offset. */ + if (tp_mac + tp_snaplen > handle->bufsize) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "corrupted frame on kernel ring mac " + "offset %d + caplen %d > frame len %d", + tp_mac, tp_snaplen, handle->bufsize); + return -1; + } + + /* run filter on received packet + * If the kernel filtering is enabled we need to run the + * filter until all the frames present into the ring + * at filter creation time are processed. + * In such case md.use_bpf is used as a counter for the + * packet we need to filter. + * Note: alternatively it could be possible to stop applying + * the filter when the ring became empty, but it can possibly + * happen a lot later... */ + bp = (unsigned char*)h.raw + tp_mac; + run_bpf = (!handle->md.use_bpf) || + ((handle->md.use_bpf>1) && handle->md.use_bpf--); + if (run_bpf && handle->fcode.bf_insns && + (bpf_filter(handle->fcode.bf_insns, bp, + tp_len, tp_snaplen) == 0)) + goto skip; + + /* check direction and interface index */ + sll = (void *)h.raw + TPACKET_ALIGN(handle->md.tp_hdrlen); + if ((sll->sll_ifindex == handle->md.lo_ifindex) && + (sll->sll_pkttype == PACKET_OUTGOING)) + goto skip; + + /* get required packet info from ring header */ + pcaphdr.ts.tv_sec = tp_sec; + pcaphdr.ts.tv_usec = tp_usec; + pcaphdr.caplen = tp_snaplen; + pcaphdr.len = tp_len; + + /* if required build in place the sll header*/ + if (handle->md.cooked) { + struct sll_header *hdrp; + + /* + * The kernel should have left us with enough + * space for an sll header; back up the packet + * data pointer into that space, as that'll be + * the beginning of the packet we pass to the + * callback. + */ + bp -= SLL_HDR_LEN; + + /* + * Let's make sure that's past the end of + * the tpacket header, i.e. >= + * ((u_char *)thdr + TPACKET_HDRLEN), so we + * don't step on the header when we construct + * the sll header. + */ + if (bp < (u_char *)h.raw + + TPACKET_ALIGN(handle->md.tp_hdrlen) + + sizeof(struct sockaddr_ll)) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "cooked-mode frame doesn't have room for sll header"); + return -1; + } + + /* + * OK, that worked; construct the sll header. + */ + hdrp = (struct sll_header *)bp; + hdrp->sll_pkttype = map_packet_type_to_sll_type( + sll->sll_pkttype); + hdrp->sll_hatype = htons(sll->sll_hatype); + hdrp->sll_halen = htons(sll->sll_halen); + memcpy(hdrp->sll_addr, sll->sll_addr, SLL_ADDRLEN); + hdrp->sll_protocol = sll->sll_protocol; + + /* update packet len */ + pcaphdr.caplen += SLL_HDR_LEN; + pcaphdr.len += SLL_HDR_LEN; + } + +#ifdef HAVE_TPACKET2 + if (handle->md.tp_version == TPACKET_V2 && h.h2->tp_vlan_tci && + tp_snaplen >= 2 * ETH_ALEN) { + struct vlan_tag *tag; + + 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(h.h2->tp_vlan_tci); + + pcaphdr.caplen += VLAN_TAG_LEN; + pcaphdr.len += VLAN_TAG_LEN; + } +#endif + + /* pass the packet to the user */ + pkts++; + callback(user, &pcaphdr, bp); + handle->md.packets_read++; + +skip: + /* next packet */ + switch (handle->md.tp_version) { + case TPACKET_V1: + h.h1->tp_status = TP_STATUS_KERNEL; + break; +#ifdef HAVE_TPACKET2 + case TPACKET_V2: + h.h2->tp_status = TP_STATUS_KERNEL; + break; +#endif + } + if (++handle->offset >= handle->cc) + handle->offset = 0; + + /* check for break loop condition*/ + if (handle->break_loop) { + handle->break_loop = 0; + return -2; + } + } + return pkts; +} + +static int +pcap_setfilter_linux_mmap(pcap_t *handle, struct bpf_program *filter) +{ + int n, offset; + int ret = pcap_setfilter_linux(handle, filter); + if (ret < 0) + return ret; + + /* if the kernel filter is enabled, we need to apply the filter on + * all packets present into the ring. Get an upper bound of their number + */ + if (!handle->md.use_bpf) + return ret; + + /* walk the ring backward and count the free slot */ + offset = handle->offset; + if (--handle->offset < 0) + handle->offset = handle->cc - 1; + for (n=0; n < handle->cc; ++n) { + if (--handle->offset < 0) + handle->offset = handle->cc - 1; + if (!pcap_get_ring_frame(handle, TP_STATUS_KERNEL)) + break; + } + + /* be careful to not change current ring position */ + handle->offset = offset; + + /* store the number of packets currently present in the ring */ + handle->md.use_bpf = 1 + (handle->cc - n); + return ret; +} + +#endif /* HAVE_PACKET_RING */ + + #ifdef HAVE_PF_PACKET_SOCKETS /* * Return the index of the given device name. Fill ebuf and return @@ -1624,6 +2420,8 @@ iface_get_id(int fd, const char *device, char *ebuf) /* * 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) @@ -1638,9 +2436,20 @@ 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? */ @@ -1648,251 +2457,815 @@ iface_bind(int fd, int ifindex, char *ebuf) 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. + * + * XXX - airmon-ng does special stuff with the Orinoco driver and the + * wlan-ng driver. */ -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. + * airmon-ng does "wlanconfig ath create wlandev {if} wlanmode + * monitor -bssid", which apparently spits out a line "athN" + * where "athN" is the monitor mode device. To leave monitor + * mode, it destroys the monitor mode device. + * + * Some Intel Centrino adapters might require private ioctls to get + * radio headers; the ipw2200 and ipw3945 drivers allow you to + * configure a separate "rtapN" interface to capture in monitor + * mode without preventing the adapter from operating normally. + * (airmon-ng doesn't appear to use that, though.) + * + * It would be Truly Wonderful if mac80211 and nl80211 cleaned this + * up, and if all drivers were converted to mac80211 drivers. + * + * If interface {if} is a mac80211 driver, the file + * /sys/class/net/{if}/phy80211 is a symlink to + * /sys/class/ieee80211/{phydev}, for some {phydev}. + * + * On Fedora 9, with a 2.6.26.3-29 kernel, my Zydas stick, at + * least, has a "wmaster0" device and a "wlan0" device; the + * latter is the one with the IP address. Both show up in + * "tcpdump -D" output. Capturing on the wmaster0 device + * captures with 802.11 headers. + * + * airmon-ng searches through /sys/class/net for devices named + * monN, starting with mon0; as soon as one *doesn't* exist, + * it chooses that as the monitor device name. If the "iw" + * command exists, it does "iw dev {if} interface add {monif} + * type monitor", where {monif} is the monitor device. It + * then (sigh) sleeps .1 second, and then configures the + * device up. Otherwise, if /sys/class/ieee80211/{phydev}/add_iface + * is a file, it writes {mondev}, without a newline, to that file, + * and again (sigh) sleeps .1 second, and then iwconfig's that + * device into monitor mode and configures it up. Otherwise, + * you can't do monitor mode. + * + * All these devices are "glued" together by having the + * /sys/class/net/{device}/phy80211 links pointing to the same + * place, so, given a wmaster, wlan, or mon device, you can + * find the other devices by looking for devices with + * the same phy80211 link. + * + * To turn monitor mode off, delete the monitor interface, + * either with "iw dev {monif} interface del" or by sending + * {monif}, with no NL, down /sys/class/ieee80211/{phydev}/remove_iface + * + * Note: if you try to create a monitor device named "monN", and + * there's already a "monN" device, it fails, as least with + * the netlink interface (which is what iw uses), with a return + * value of -ENFILE. (Return values are negative errnos.) We + * could probably use that to find an unused device. + */ + int err; + struct iwreq ireq; + struct iw_priv_args *priv; + monitor_type montype; + int i; + __u32 cmd; + 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) { + + 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) { + /* + * 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; + } - if (handle->md.clear_promisc) { + /* + * 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 put the interface into promiscuous mode; take - * it out of promiscuous mode. + * 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; + } + + /* + * XXX - airmon-ng does "iwconfig {if} key off" after setting + * monitor mode and setting the channel, and then does + * "iwconfig up". + */ + + /* + * Now select the appropriate radio header. + */ + switch (montype) { + + case MONITOR_WEXT: + /* + * 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) { /* - * Default value for offset to align link-layer payload - * on a 4-byte boundary. + * 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. */ - handle->offset = 0; - - return 1; + 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 { + /* + * This is a 2.2[.x] or later kernel. + * + * We can safely pass "recvfrom()" a byte count + * based on the snapshot length. + */ + 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; } /* @@ -1971,7 +3344,13 @@ iface_get_arptype(int fd, const char *device, char *ebuf) 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; @@ -1995,7 +3374,7 @@ fix_program(pcap_t *handle, struct sock_fprog *fcode) 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; } @@ -2167,7 +3546,7 @@ set_kernel_filter(pcap_t *handle, struct sock_fprog *fcode) 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; } |