| /* |
| * pcap-linux.c: Packet capture interface to the Linux kernel |
| * |
| * Copyright (c) 2000 Torsten Landschoff <torsten@debian.org> |
| * Sebastian Krahmer <krahmer@cs.uni-potsdam.de> |
| * |
| * License: BSD |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * 3. The names of the authors may not be used to endorse or promote |
| * products derived from this software without specific prior |
| * written permission. |
| * |
| * 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. |
| */ |
| #ifndef lint |
| static const char rcsid[] = |
| "@(#) $Header: /tcpdump/master/libpcap/pcap-linux.c,v 1.35 2000-10-20 06:55:28 guy Exp $ (LBL)"; |
| #endif |
| |
| /* |
| * Known bugs: |
| * - setting promiscuous on loopback gives every packet twice |
| */ |
| |
| |
| #ifdef HAVE_CONFIG_H |
| #include "config.h" |
| #endif |
| |
| #include "pcap-int.h" |
| |
| #include <errno.h> |
| #include <stdlib.h> |
| #include <unistd.h> |
| #include <fcntl.h> |
| #include <string.h> |
| #include <sys/socket.h> |
| #include <sys/ioctl.h> |
| #include <net/if.h> |
| #include <netinet/in.h> |
| #include <linux/if_ether.h> |
| #include <netinet/if_ether.h> |
| |
| #ifdef HAVE_NETPACKET_PACKET_H |
| #include <netpacket/packet.h> |
| #endif |
| #ifdef SO_ATTACH_FILTER |
| #include <linux/types.h> |
| #include <linux/filter.h> |
| #endif |
| |
| #ifndef __GLIBC__ |
| typedef int socklen_t; |
| #endif |
| |
| #ifndef MSG_TRUNC |
| #define MSG_TRUNC 0 |
| #endif |
| |
| #define MAX_LINKHEADER_SIZE 256 |
| |
| /* |
| * When capturing on all interfaces we use this as the buffer size. |
| * Should be bigger then all MTUs that occur in real life. |
| * 64kB should be enough for now. |
| */ |
| #define BIGGER_THAN_ALL_MTUS (64*1024) |
| |
| /* |
| * Prototypes for internal functions |
| */ |
| static int map_arphrd_to_dlt(int arptype ); |
| static int live_open_old(pcap_t *, char *, int, int, char *); |
| static int live_open_new(pcap_t *, char *, int, int, char *); |
| static int pcap_read_packet(pcap_t *, pcap_handler, u_char *); |
| |
| /* |
| * Wrap some ioctl calls |
| */ |
| #ifdef HAVE_NETPACKET_PACKET_H |
| static int iface_get_id(int fd, const char *device, char *ebuf); |
| #endif |
| static int iface_get_mtu(int fd, const char *device, char *ebuf); |
| static int iface_get_arptype(int fd, const char *device, char *ebuf); |
| #ifdef HAVE_NETPACKET_PACKET_H |
| static int iface_bind(int fd, int ifindex, char *ebuf); |
| #endif |
| static int iface_bind_old(int fd, const char *device, char *ebuf); |
| |
| /* |
| * 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(char *device, int snaplen, int promisc, int to_ms, char *ebuf) |
| { |
| /* Allocate a handle for this session. */ |
| |
| pcap_t *handle = malloc(sizeof(*handle)); |
| if (handle == NULL) { |
| snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s", |
| pcap_strerror(errno)); |
| return NULL; |
| } |
| |
| /* Initialize some components of the pcap structure. */ |
| |
| memset(handle, 0, sizeof(*handle)); |
| handle->snapshot = snaplen; |
| handle->md.timeout = to_ms; |
| handle->md.promisc = promisc; |
| |
| /* |
| * NULL and "any" are special devices which give us the hint to |
| * monitor all devices. |
| */ |
| if (!device || strcmp(device, "any") == 0) { |
| device = NULL; |
| handle->md.device = strdup("any"); |
| } else |
| handle->md.device = strdup(device); |
| |
| if (handle->md.device == NULL) { |
| snprintf(ebuf, PCAP_ERRBUF_SIZE, "strdup: %s", |
| pcap_strerror(errno) ); |
| free(handle); |
| return NULL; |
| } |
| |
| /* |
| * Current Linux kernels use the protocol family PF_PACKET to |
| * allow direct access to all packets on the network while |
| * older kernels had a special socket type SOCK_PACKET to |
| * implement this feature. |
| * While this old implementation is kind of obsolete we need |
| * to be compatible with older kernels for a while so we are |
| * trying both methods with the newer method preferred. |
| */ |
| |
| if (! (live_open_new(handle, device, promisc, to_ms, ebuf) || |
| live_open_old(handle, device, promisc, to_ms, ebuf)) ) |
| { |
| /* |
| * Both methods to open the packet socket failed. Tidy |
| * up and report our failure (ebuf is expected to be |
| * set by the functions above). |
| */ |
| |
| free(handle->md.device); |
| free(handle); |
| return NULL; |
| } |
| |
| /* |
| * Okay, now we have a packet stream open. Maybe we need to handle |
| * a timeout? In that case we set the filehandle to nonblocking |
| * so pcap_read can try reading the fd and call select if no data |
| * is available at first. |
| */ |
| |
| if (to_ms > 0) { |
| int flags = fcntl(handle->fd, F_GETFL); |
| if (flags != -1) { |
| flags |= O_NONBLOCK; |
| flags = fcntl(handle->fd, F_SETFL, flags); |
| } |
| if (flags == -1) { |
| snprintf(ebuf, PCAP_ERRBUF_SIZE, "fcntl: %s", |
| pcap_strerror(errno)); |
| pcap_close(handle); |
| return NULL; |
| } |
| } |
| |
| return handle; |
| } |
| |
| /* |
| * Read at most max_packets from the capture stream and call the callback |
| * for each of them. Returns the number of packets handled or -1 if an |
| * error occured. |
| * |
| * XXX: Can I rely on the Linux-specified behaviour of select (returning |
| * the time left in the timeval structure)? I really don't want to query |
| * the system time before each select call... |
| * |
| * pcap_read currently gets not only a packet from the kernel but also |
| * the sockaddr_ll returned as source of the packet. This way we can at |
| * some time extend tcpdump and libpcap to sniff on all devices at a time |
| * and find the right printing routine by using the information in the |
| * sockaddr_ll structure. |
| */ |
| int |
| pcap_read(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user) |
| { |
| int status, packets; |
| fd_set read_fds; |
| struct timeval tv; |
| |
| /* |
| * Fill in a timeval structure for select if we need to obeye a |
| * timeout. |
| */ |
| if (handle->md.timeout > 0) { |
| tv.tv_usec = (handle->md.timeout % 1000) * 1000; |
| tv.tv_sec = (handle->md.timeout / 1000); |
| } |
| |
| /* |
| * Read packets until the packet limit has been reached or |
| * an error occured while reading. Call the user function |
| * for each received packet. |
| */ |
| for (packets = 0; max_packets == -1 || packets < max_packets;) |
| { |
| status = pcap_read_packet(handle, callback, user); |
| |
| if (status > 0) { |
| packets += status; |
| continue; |
| } else if (status == -1) |
| return -1; |
| |
| /* |
| * If no packet is available we go to sleep. FIXME: This |
| * might be better implemented using poll(?) |
| */ |
| FD_ZERO(&read_fds); |
| FD_SET(handle->fd, &read_fds); |
| status = select(handle->fd + 1, |
| &read_fds, NULL, NULL, &tv); |
| |
| if (status == -1) { |
| if (errno == EINTR) |
| return packets; |
| snprintf(handle->errbuf, sizeof(handle->errbuf), |
| "select: %s", pcap_strerror(errno)); |
| return -1; |
| } |
| else if (status == 0 || |
| (tv.tv_usec == 0 && tv.tv_sec == 0)) |
| return packets; |
| } |
| |
| return packets; |
| } |
| |
| /* |
| * Read a packet from the socket calling the handler provided by |
| * the user. Returns the number of packets received or -1 if an |
| * error occured. |
| */ |
| static int |
| pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata) |
| { |
| struct sockaddr from; |
| socklen_t fromlen; |
| int packet_len, caplen; |
| struct pcap_pkthdr pcap_header; |
| |
| /* |
| * We don't currently use the from return value of recvfrom but |
| * this will probably be implemented in the future. |
| */ |
| |
| /* Receive a single packet from the kernel */ |
| |
| do { |
| fromlen = sizeof(from); |
| packet_len = recvfrom( |
| handle->fd, handle->buffer + handle->offset, |
| handle->snapshot, MSG_TRUNC, |
| (struct sockaddr *) &from, &fromlen); |
| } while (packet_len == -1 && errno == EINTR); |
| |
| /* Check if an error occured */ |
| |
| if (packet_len == -1) { |
| if (errno == EAGAIN) |
| return 0; /* no packet there */ |
| else { |
| snprintf(handle->errbuf, sizeof(handle->errbuf), |
| "recvfrom: %s", pcap_strerror(errno)); |
| return -1; |
| } |
| } |
| |
| /* |
| * XXX: According to the kernel source we should get the real |
| * packet len if calling recvfrom with MSG_TRUNC set. It does |
| * not seem to work here :(, but it is supported by this code |
| * anyway. |
| * To be honest the code RELIES on that feature so this is really |
| * broken with 2.2.x kernels. |
| * I spend a day to figure out what's going on and I found out |
| * that the following is happening: |
| * |
| * The packet comes from a random interface and the packet_rcv |
| * hook is called with a clone of the packet. That code inserts |
| * the packet into the receive queue of the packet socket. |
| * If a filter is attached to that socket that filter is run |
| * first - and there lies the problem. The default filter always |
| * cuts the packet at the snaplen: |
| * |
| * # tcpdump -d |
| * (000) ret #68 |
| * |
| * So the packet filter cuts down the packet. The recvfrom call |
| * says "hey, it's only 68 bytes, it fits into the buffer" with |
| * the result that we don't get the real packet length. This |
| * is valid at least until kernel 2.2.17pre6. |
| * |
| * tcpdump is currently fixed by changing the BPF code generator |
| * to not truncate the received packet. |
| */ |
| |
| caplen = packet_len; |
| if (caplen > handle->snapshot) |
| caplen = handle->snapshot; |
| |
| /* Run the packet filter if not using kernel filter */ |
| if (!handle->md.use_bpf && handle->fcode.bf_insns) { |
| if (bpf_filter(handle->fcode.bf_insns, handle->buffer, |
| packet_len, caplen) == 0) |
| { |
| /* rejected by filter */ |
| return 0; |
| } |
| } |
| |
| /* Fill in our own header data */ |
| |
| if (ioctl(handle->fd, SIOCGSTAMP, &pcap_header.ts) == -1) { |
| snprintf(handle->errbuf, sizeof(handle->errbuf), |
| "ioctl: %s", pcap_strerror(errno)); |
| return -1; |
| } |
| pcap_header.caplen = caplen; |
| pcap_header.len = packet_len; |
| |
| /* Call the user supplied callback function */ |
| handle->md.stat.ps_recv++; |
| callback(userdata, &pcap_header, handle->buffer + handle->offset); |
| |
| return 1; |
| } |
| |
| /* |
| * Get the statistics for the given packet capture handle. |
| * FIXME: Currently does not report the number of dropped packets. |
| */ |
| int |
| pcap_stats(pcap_t *handle, struct pcap_stat *stats) |
| { |
| *stats = handle->md.stat; |
| return 0; |
| } |
| |
| /* |
| * Attach the given BPF code to the packet capture device. |
| */ |
| int |
| pcap_setfilter(pcap_t *handle, struct bpf_program *filter) |
| { |
| #ifdef SO_ATTACH_FILTER |
| struct sock_fprog fcode; |
| #endif |
| |
| if (!handle) |
| return -1; |
| if (!filter) { |
| strncpy(handle->errbuf, "setfilter: No filter specified", |
| sizeof(handle->errbuf)); |
| return -1; |
| } |
| |
| /* Free old filter code if existing */ |
| |
| handle->fcode.bf_len = 0; |
| if (handle->fcode.bf_insns) { |
| free(handle->fcode.bf_insns); |
| handle->fcode.bf_insns = NULL; |
| } |
| |
| |
| /* Make our private copy of the filter */ |
| |
| handle->fcode.bf_len = filter->bf_len; |
| handle->fcode.bf_insns = |
| malloc(filter->bf_len * sizeof(*filter->bf_insns)); |
| if (handle->fcode.bf_insns == NULL) { |
| snprintf(handle->errbuf, sizeof(handle->errbuf), |
| "malloc: %s", pcap_strerror(errno)); |
| return -1; |
| } |
| memcpy(handle->fcode.bf_insns, filter->bf_insns, |
| filter->bf_len * sizeof(*filter->bf_insns)); |
| |
| /* |
| * Run user level packet filter by default. Will be overriden if |
| * installing a kernel filter succeeds. |
| */ |
| handle->md.use_bpf = 0; |
| |
| /* Install kernel level filter if possible */ |
| |
| #ifdef SO_ATTACH_FILTER |
| /* |
| * Oh joy, the Linux kernel uses struct sock_fprog instead of |
| * struct bpf_program and of course the length field is of |
| * different size. Pointed out by Sebastian |
| */ |
| |
| fcode.filter = (struct sock_filter *) handle->fcode.bf_insns; |
| fcode.len = filter->bf_len; |
| #ifdef USHRT_MAX |
| if (filter->bf_len > USHRT_MAX) { |
| /* |
| * fcode.len is an unsigned short for current kernel. |
| * I have yet to see BPF-Code with that much instructions |
| * but still it is possible. So for the sake of |
| * correctness I added this check. |
| */ |
| fprintf(stderr, "Warning: Filter to complex for kernel\n"); |
| } |
| else |
| #endif |
| if (setsockopt(handle->fd, SOL_SOCKET, SO_ATTACH_FILTER, |
| &fcode, sizeof(fcode)) == 0) |
| { |
| /* Installation succeded - using kernel filter. */ |
| handle->md.use_bpf = 1; |
| } |
| else |
| { |
| /* |
| * Print a warning if kernel filter available but a problem |
| * occured using it. |
| */ |
| if (errno != ENOPROTOOPT && errno != EOPNOTSUPP) { |
| fprintf(stderr, "Warning: Kernel filter failed: %s\n", |
| pcap_strerror(errno)); |
| } |
| } |
| #endif |
| |
| return 0; |
| } |
| |
| /* |
| * Linux uses the ARP hardware type to identify the type of an |
| * interface. pcap uses the DLT_xxx constants for this. This |
| * function maps the ARPHRD_xxx constant to an appropriate |
| * DLT_xxx constant. |
| * |
| * Returns -1 if unable to map the type. |
| */ |
| static int map_arphrd_to_dlt(int arptype) |
| { |
| switch (arptype) { |
| case ARPHRD_ETHER: |
| case ARPHRD_METRICOM: |
| case ARPHRD_LOOPBACK: return DLT_EN10MB; |
| case ARPHRD_EETHER: return DLT_EN3MB; |
| case ARPHRD_AX25: return DLT_AX25; |
| case ARPHRD_PRONET: return DLT_PRONET; |
| case ARPHRD_CHAOS: return DLT_CHAOS; |
| case ARPHRD_IEEE802: return DLT_IEEE802; |
| case ARPHRD_ARCNET: return DLT_ARCNET; |
| case ARPHRD_FDDI: return DLT_FDDI; |
| |
| #ifndef ARPHRD_ATM /* FIXME: How to #include this? */ |
| #define ARPHRD_ATM 19 |
| #endif |
| case ARPHRD_ATM: return DLT_ATM_CLIP; |
| |
| case ARPHRD_PPP: |
| case ARPHRD_CSLIP: |
| case ARPHRD_SLIP6: |
| case ARPHRD_CSLIP6: |
| case ARPHRD_SLIP: return DLT_RAW; |
| } |
| |
| return -1; |
| } |
| |
| /* ===== 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) |
| */ |
| static int |
| live_open_new(pcap_t *handle, char *device, int promisc, |
| int to_ms, char *ebuf) |
| { |
| #ifdef HAVE_NETPACKET_PACKET_H |
| int sock_fd = -1, device_id, mtu, arptype; |
| struct packet_mreq mr; |
| |
| /* 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; |
| } |
| |
| /* It seems the kernel supports the new interface. */ |
| handle->md.sock_packet = 0; |
| |
| /* |
| * What kind of frames do we have to deal with? Fall back |
| * to cooked mode if we have an unknown interface type. |
| */ |
| |
| if (device) { |
| arptype = iface_get_arptype(sock_fd, device, ebuf); |
| if (arptype == -1) |
| break; |
| handle->linktype = map_arphrd_to_dlt(arptype); |
| } else |
| handle->linktype = DLT_RAW; |
| |
| if (handle->linktype == -1) { |
| /* Unknown interface type - 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; |
| } |
| |
| fprintf(stderr, |
| "Warning: Falling back to cooked socket\n"); |
| handle->linktype = DLT_RAW; |
| } |
| |
| |
| if (device) { |
| device_id = iface_get_id(sock_fd, device, ebuf); |
| if (device_id == -1) |
| break; |
| |
| if (iface_bind(sock_fd, device_id, ebuf) == -1) |
| break; |
| } |
| |
| /* Select promiscous mode on/off */ |
| |
| #ifdef SOL_PACKET |
| /* |
| * Hmm, how can we set promiscuous mode on all interfaces? |
| * I am not sure if that is possible at all. |
| */ |
| |
| if (device) { |
| memset(&mr, 0, sizeof(mr)); |
| mr.mr_ifindex = device_id; |
| mr.mr_type = promisc ? |
| PACKET_MR_PROMISC : PACKET_MR_ALLMULTI; |
| if (setsockopt(sock_fd, SOL_PACKET, |
| PACKET_ADD_MEMBERSHIP, &mr, sizeof(mr)) == -1) |
| { |
| snprintf(ebuf, PCAP_ERRBUF_SIZE, |
| "setsockopt: %s", pcap_strerror(errno)); |
| break; |
| } |
| } |
| #endif |
| |
| /* Compute the buffersize */ |
| |
| mtu = iface_get_mtu(sock_fd, device, ebuf); |
| if (mtu == -1) |
| break; |
| handle->bufsize = MAX_LINKHEADER_SIZE + mtu; |
| if (handle->bufsize < handle->snapshot) |
| handle->bufsize = handle->snapshot; |
| |
| /* Fill in the pcap structure */ |
| |
| handle->fd = sock_fd; |
| handle->offset = 0; |
| |
| handle->buffer = malloc(handle->bufsize); |
| if (!handle->buffer) { |
| snprintf(ebuf, PCAP_ERRBUF_SIZE, |
| "malloc: %s", pcap_strerror(errno)); |
| break; |
| } |
| |
| return 1; |
| |
| } while(0); |
| |
| if (sock_fd != -1) |
| close(sock_fd); |
| return 0; |
| #else |
| strncpy(ebuf, |
| "New packet capturing interface not supported by build " |
| "environment", PCAP_ERRBUF_SIZE); |
| return 0; |
| #endif |
| } |
| |
| #ifdef HAVE_NETPACKET_PACKET_H |
| /* |
| * Return the index of the given device name. Fill ebuf and return |
| * -1 on failure. |
| */ |
| static int |
| iface_get_id(int fd, const char *device, char *ebuf) |
| { |
| struct ifreq ifr; |
| |
| memset(&ifr, 0, sizeof(ifr)); |
| strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); |
| |
| if (ioctl(fd, SIOCGIFINDEX, &ifr) == -1) { |
| snprintf(ebuf, PCAP_ERRBUF_SIZE, |
| "ioctl: %s", pcap_strerror(errno)); |
| return -1; |
| } |
| |
| return ifr.ifr_ifindex; |
| } |
| |
| /* |
| * Bind the socket associated with FD to the given device. |
| */ |
| static int |
| iface_bind(int fd, int ifindex, char *ebuf) |
| { |
| struct sockaddr_ll sll; |
| |
| memset(&sll, 0, sizeof(sll)); |
| sll.sll_family = AF_PACKET; |
| sll.sll_ifindex = ifindex; |
| sll.sll_protocol = htons(ETH_P_ALL); |
| |
| if (bind(fd, (struct sockaddr *) &sll, sizeof(sll)) == -1) { |
| snprintf(ebuf, PCAP_ERRBUF_SIZE, |
| "bind: %s", pcap_strerror(errno)); |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| #endif |
| |
| |
| /* ===== Functions to interface to the older kernels ================== */ |
| |
| /* |
| * With older kernels promiscuous mode is kind of interesting because we |
| * have to reset the interface before exiting. The problem can't really |
| * be solved without some daemon taking care of managing usage counts. |
| * We save the promiscuous state of the device when opening the capture |
| * stream and arrange for it to be reset on process exit. |
| * |
| * XXX: This solution is still not correct even for this case. The |
| * devices stay in promiscuous mode until the process exits. I need to |
| * modify pcap_close to solve this. |
| */ |
| |
| /* |
| * The device name and the interface flags to be restored at exit |
| */ |
| struct ifreq restore_ifr; |
| |
| static void restore_interface( void ) |
| { |
| int status = socket(PF_INET, SOCK_PACKET, 0); |
| |
| if (status != -1) |
| status = ioctl(status, SIOCSIFFLAGS, &restore_ifr); |
| |
| if (status == -1) { |
| fprintf(stderr, |
| "Can't restore interface flags. Please adjust manually. \n" |
| "Hint: This can't happen with Linux >= 2.2.0.\n"); |
| } |
| } |
| |
| /* |
| * Try to open a packet socket using the old kernel interface. |
| * Returns 0 on failure. |
| * FIXME: 0 uses to mean success (Sebastian) |
| */ |
| static int |
| live_open_old(pcap_t *handle, char *device, int promisc, |
| int to_ms, char *ebuf) |
| { |
| int sock_fd = -1, mtu, arptype; |
| struct ifreq ifr; |
| |
| do { |
| /* Open the socket */ |
| |
| sock_fd = socket(PF_INET, SOCK_PACKET, htons(ETH_P_ALL)); |
| if (sock_fd == -1) { |
| snprintf(ebuf, PCAP_ERRBUF_SIZE, |
| "socket: %s", pcap_strerror(errno)); |
| break; |
| } |
| |
| /* It worked - we are using the old interface */ |
| handle->md.sock_packet = 1; |
| |
| /* Bind to the given device */ |
| |
| if (!device) { |
| strncpy(ebuf, "pcap_open_live: No interface given", |
| PCAP_ERRBUF_SIZE); |
| break; |
| } |
| if (iface_bind_old(sock_fd, device, ebuf) == -1) |
| break; |
| |
| /* Go to promisc mode */ |
| if (promisc) { |
| memset(&ifr, 0, sizeof(ifr)); |
| strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); |
| if (ioctl(sock_fd, SIOCGIFFLAGS, &ifr) == -1) { |
| snprintf(ebuf, PCAP_ERRBUF_SIZE, |
| "ioctl: %s", pcap_strerror(errno)); |
| break; |
| } |
| if ((ifr.ifr_flags & IFF_PROMISC) == 0) { |
| restore_ifr = ifr; |
| ifr.ifr_flags |= IFF_PROMISC; |
| if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) { |
| snprintf(ebuf, PCAP_ERRBUF_SIZE, |
| "ioctl: %s", |
| pcap_strerror(errno)); |
| break; |
| } |
| if (atexit(restore_interface) == -1) { |
| restore_interface(); |
| strncpy(ebuf, "atexit failed", |
| PCAP_ERRBUF_SIZE); |
| break; |
| } |
| } |
| } |
| |
| |
| /* Compute the buffersize */ |
| |
| mtu = iface_get_mtu(sock_fd, device, ebuf); |
| if (mtu == -1) |
| break; |
| handle->bufsize = MAX_LINKHEADER_SIZE + mtu; |
| if (handle->bufsize < handle->snapshot) |
| handle->bufsize = handle->snapshot; |
| |
| /* All done - fill in the pcap handle */ |
| |
| arptype = iface_get_arptype(sock_fd, device, ebuf); |
| if (arptype == -1) |
| break; |
| |
| handle->fd = sock_fd; |
| handle->offset = 0; |
| handle->linktype = map_arphrd_to_dlt(arptype); |
| if (handle->linktype == -1) { |
| snprintf(ebuf, PCAP_ERRBUF_SIZE, |
| "interface type of %s not supported", device); |
| break; |
| } |
| handle->buffer = malloc(handle->bufsize); |
| if (!handle->buffer) { |
| snprintf(ebuf, PCAP_ERRBUF_SIZE, |
| "malloc: %s", pcap_strerror(errno)); |
| break; |
| } |
| |
| return 1; |
| |
| } while (0); |
| |
| if (sock_fd != -1) |
| close(sock_fd); |
| return 0; |
| } |
| |
| /* |
| * Bind the socket associated with FD to the given device using the |
| * interface of the old kernels. |
| */ |
| static int |
| iface_bind_old(int fd, const char *device, char *ebuf) |
| { |
| struct sockaddr saddr; |
| |
| memset(&saddr, 0, sizeof(saddr)); |
| strncpy(saddr.sa_data, device, sizeof(saddr.sa_data)); |
| if (bind(fd, &saddr, sizeof(saddr)) == -1) { |
| snprintf(ebuf, PCAP_ERRBUF_SIZE, |
| "bind: %s", pcap_strerror(errno)); |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| |
| /* ===== System calls available on all supported kernels ============== */ |
| |
| /* |
| * Query the kernel for the MTU of the given interface. |
| */ |
| static int |
| iface_get_mtu(int fd, const char *device, char *ebuf) |
| { |
| struct ifreq ifr; |
| |
| if (!device) |
| return BIGGER_THAN_ALL_MTUS; |
| |
| memset(&ifr, 0, sizeof(ifr)); |
| strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); |
| |
| if (ioctl(fd, SIOCGIFMTU, &ifr) == -1) { |
| snprintf(ebuf, PCAP_ERRBUF_SIZE, |
| "ioctl: %s", pcap_strerror(errno)); |
| return -1; |
| } |
| |
| return ifr.ifr_mtu; |
| } |
| |
| /* |
| * Get the hardware type of the given interface as ARPHRD_xxx constant. |
| */ |
| static int |
| iface_get_arptype(int fd, const char *device, char *ebuf) |
| { |
| struct ifreq ifr; |
| |
| memset(&ifr, 0, sizeof(ifr)); |
| strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); |
| |
| if (ioctl(fd, SIOCGIFHWADDR, &ifr) == -1) { |
| snprintf(ebuf, PCAP_ERRBUF_SIZE, |
| "ioctl: %s", pcap_strerror(errno)); |
| return -1; |
| } |
| |
| return ifr.ifr_hwaddr.sa_family; |
| } |