X-Git-Url: https://git.tcpdump.org/libpcap/blobdiff_plain/d2ae6943a6b0d960c647c9a3c6fac1b61146cb19..83b51abcee9dffe2a58c564fb390ce3a3e772f1a:/pcap-linux.c diff --git a/pcap-linux.c b/pcap-linux.c index b84f94dc..bef5c437 100644 --- a/pcap-linux.c +++ b/pcap-linux.c @@ -34,7 +34,7 @@ #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 /* @@ -84,6 +84,28 @@ static const char rcsid[] _U_ = #include "config.h" #endif +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * Got Wireless Extensions? + */ +#ifdef HAVE_LINUX_WIRELESS_H +#include +#endif + #include "pcap-int.h" #include "pcap/sll.h" @@ -103,21 +125,6 @@ static const char rcsid[] _U_ = #include "pcap-bt-linux.h" #endif -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - /* * If PF_PACKET is defined, we can use {SOCK_RAW,SOCK_DGRAM}/PF_PACKET * sockets rather than SOCK_PACKET sockets. @@ -174,7 +181,7 @@ static const char rcsid[] _U_ = #include #endif -#ifndef __GLIBC__ +#ifndef HAVE_SOCKLEN_T typedef int socklen_t; #endif @@ -210,27 +217,31 @@ 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); +#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); @@ -247,6 +258,9 @@ 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); @@ -262,64 +276,220 @@ 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 */ #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; @@ -327,7 +497,7 @@ pcap_open_live(const char *device, int snaplen, int promisc, int to_ms, 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; @@ -338,21 +508,21 @@ 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; } /* @@ -365,121 +535,50 @@ 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; - 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; } /* @@ -488,7 +587,11 @@ pcap_open_live(const char *device, int snaplen, int promisc, int to_ms, */ handle->selectable_fd = handle->fd; - return handle; + return status; + +fail: + pcap_cleanup_linux(handle); + return status; } /* @@ -522,10 +625,10 @@ pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata) #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 @@ -543,9 +646,34 @@ 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; + + 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? @@ -559,12 +687,9 @@ pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata) 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 */ @@ -572,7 +697,7 @@ 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; } @@ -700,7 +825,7 @@ 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; } @@ -963,7 +1088,7 @@ 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; } @@ -1101,12 +1226,13 @@ 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 @@ -1139,6 +1265,7 @@ map_packet_type_to_sll_type(short int sll_pkttype) return -1; } } +#endif /* * Linux uses the ARP hardware type to identify the type of an @@ -1176,7 +1303,7 @@ 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? */ @@ -1434,6 +1561,17 @@ 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; @@ -1443,218 +1581,251 @@ 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 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 " @@ -1664,20 +1835,25 @@ live_open_new(pcap_t *handle, const char *device, int promisc, } 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; @@ -1705,7 +1881,7 @@ compute_ring_block(int frame_size, unsigned *block_size, unsigned *frames_per_bl } 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; @@ -1716,7 +1892,7 @@ create_ring(pcap_t* handle, unsigned size, char* errmsg) * 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; @@ -1733,7 +1909,7 @@ retry: 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; @@ -1744,7 +1920,7 @@ retry: 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*/ @@ -1795,34 +1971,28 @@ destroy_ring(pcap_t *handle) 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; @@ -1864,9 +2034,9 @@ pcap_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, } 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; @@ -1879,7 +2049,7 @@ pcap_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, 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; } @@ -1915,8 +2085,34 @@ pcap_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, /* 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); @@ -2009,6 +2205,8 @@ 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) @@ -2023,9 +2221,20 @@ 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? */ @@ -2033,251 +2242,763 @@ 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. */ -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; } /* @@ -2356,7 +3077,13 @@ 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; @@ -2380,7 +3107,7 @@ 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; } @@ -2552,7 +3279,7 @@ 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; }