| /* |
| 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. |
| */ |
| |
| /* |
| TODO: |
| |
| - Make it compatible with older Linux installations (at compilation time) |
| |
| BUGS: |
| |
| - setting promiscuous on loopback for example gives every packet |
| twice |
| */ |
| |
| |
| /* |
| FYI: |
| |
| pcap_read currently reads 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. |
| */ |
| |
| |
| #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 |
| |
| /* 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 */ |
| static int iface_get_id( int fd, const char *device, char *ebuf ); |
| static int iface_get_mtu( int fd, const char *device, char *ebuf ); |
| static int iface_get_arptype( int fd, const char *device, char *ebuf ); |
| static int iface_bind( int fd, int ifindex, char *ebuf ); |
| static int iface_bind_old( int fd, const char *device, char *ebuf ); |
| |
| /* |
| pcap_open_live: |
| |
| 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; |
| 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 once. */ |
| |
| 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; |
| } |
| |
| /* |
| pcap_read: |
| |
| 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... |
| */ |
| 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; |
| |
| if( handle->md.timeout > 0 ) { |
| tv.tv_usec = (handle->md.timeout % 1000) * 1000; |
| tv.tv_sec = (handle->md.timeout / 1000); |
| } |
| |
| for( packets = 0; max_packets == -1 || packets < max_packets; ) |
| { |
| status = pcap_read_packet( handle, callback, user ); |
| |
| if( status > 0 ) { |
| packets++; |
| continue; |
| } else if( status == -1 ) |
| return -1; |
| |
| /* paranoia - the recvmsg call should block if we don't use |
| * a timeout */ |
| if( handle->md.timeout <= 0 ) |
| continue; |
| |
| /* No packet available - go to sleep */ |
| FD_ZERO( &read_fds ); |
| FD_SET( handle->fd, &read_fds ); |
| status = select( handle->fd + 1, |
| &read_fds, NULL, NULL, &tv ); |
| if( status == -1 ) { |
| 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; |
| } |
| |
| /* |
| pcap_read_packet: |
| |
| Read a packet from the socket calling the handler provided by |
| the user. Returns 0 if no packet was there, 1 if a packet was |
| handled and -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 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 some 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. */ |
| |
| 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; |
| } |
| |
| /* |
| pcap_stats: |
| |
| Get the statistics for the given packet capture handle. |
| */ |
| int |
| pcap_stats( pcap_t *handle, struct pcap_stat *stats ) |
| { |
| *stats = handle->md.stat; |
| return 0; |
| } |
| |
| /* |
| pcap_setfilter: |
| |
| 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 ) { |
| fprintf( stderr, "Warning: Filter to complex for kernel\n" ); |
| /* paranoid - should never happen */ |
| } |
| else |
| #endif |
| if( setsockopt(handle->fd, SOL_SOCKET, SO_ATTACH_FILTER, |
| &fcode, sizeof(fcode)) == 0 ) |
| { |
| 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; |
| } |
| |
| |
| /* |
| map_arphrd_to_dlt: |
| |
| 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; |
| |
| 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 ================== */ |
| |
| /* |
| live_open_new: |
| |
| 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. */ |
| sock_fd = socket( PF_PACKET, SOCK_RAW, 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; |
| |
| /* Currently we only support monitoring a single interface. |
| * While the kernel can do more I want to reimplement the |
| * old features first before adding more. */ |
| |
| if( !device ) { |
| snprintf(ebuf, PCAP_ERRBUF_SIZE, |
| "pcap_open_live: No device given" ); |
| break; |
| } |
| |
| /* What kind of frames do we have to deal with? Fall back |
| * to cooked mode if we have an unknown interface type. */ |
| |
| arptype = iface_get_arptype(sock_fd, device, ebuf); |
| if( arptype == -1 ) |
| break; |
| handle->linktype = map_arphrd_to_dlt( arptype ); |
| 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; |
| } |
| |
| |
| 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 |
| /* XXX: We got reports that this does not work in 2.3.99. |
| * Need to investigate. Using ioctl to switch the promisc |
| * mode at device level costs us most of the benefits of |
| * using the new kernel interface. |
| * UPDATE: I found the bug. The kernel checks mr_alen |
| * even if it is of zero interest for the request. A |
| * random value there made the kernel return EINVAL. |
| * Probably the right solution is to memset the whole |
| * struct at first. */ |
| |
| 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; |
| |
| /* 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 |
| /* |
| iface_get_id: |
| |
| 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; |
| } |
| |
| /* |
| iface_bind: |
| |
| 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. */ |
| |
| struct ifreq restore_ifr; |
| /* Contains the device name and the interface flags to be restored |
| * at exit */ |
| |
| 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"); |
| } |
| } |
| |
| /* |
| live_open_old: |
| |
| 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; |
| |
| /* 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; |
| } |
| |
| /* |
| iface_bind_old: |
| |
| 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 ============== */ |
| |
| /* |
| iface_get_mtu: |
| |
| 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; |
| |
| 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; |
| } |
| |
| /* |
| iface_get_arptype: |
| |
| 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; |
| } |
| |