/* * Copyright (c) 1993, 1994, 1995, 1996, 1998 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that: (1) source code distributions * retain the above copyright notice and this paragraph in its entirety, (2) * distributions including binary code include the above copyright notice and * this paragraph in its entirety in the documentation or other materials * provided with the distribution, and (3) all advertising materials mentioning * features or use of this software display the following acknowledgement: * ``This product includes software developed by the University of California, * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of * the University nor the names of its contributors may 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[] _U_ = "@(#) $Header: /tcpdump/master/libpcap/pcap-bpf.c,v 1.116 2008-09-16 18:42:29 guy Exp $ (LBL)"; #endif #ifdef HAVE_CONFIG_H #include "config.h" #endif #include /* optionally get BSD define */ #ifdef HAVE_ZEROCOPY_BPF #include #endif #include #include /* * defines ioctls, but doesn't include . * * We include as it might be necessary to declare ioctl(); * at least on *BSD and Mac OS X, it also defines various SIOC ioctls - * we could include , but if we're already including * , which includes on those platforms, * there's not much point in doing so. * * If we have , we include it as well, to handle systems * such as Solaris which don't arrange to include if you * include */ #include #ifdef HAVE_SYS_IOCCOM_H #include #endif #include #ifdef HAVE_ZEROCOPY_BPF #include #endif #include #ifdef _AIX /* * Make "pcap.h" not include "pcap/bpf.h"; we are going to include the * native OS version, as we need "struct bpf_config" from it. */ #define PCAP_DONT_INCLUDE_PCAP_BPF_H #include /* * Prevent bpf.h from redefining the DLT_ values to their * IFT_ values, as we're going to return the standard libpcap * values, not IBM's non-standard IFT_ values. */ #undef _AIX #include #define _AIX #include /* for IFT_ values */ #include #include #include #include #ifdef __64BIT__ #define domakedev makedev64 #define getmajor major64 #define bpf_hdr bpf_hdr32 #else /* __64BIT__ */ #define domakedev makedev #define getmajor major #endif /* __64BIT__ */ #define BPF_NAME "bpf" #define BPF_MINORS 4 #define DRIVER_PATH "/usr/lib/drivers" #define BPF_NODE "/dev/bpf" static int bpfloadedflag = 0; static int odmlockid = 0; static int bpf_load(char *errbuf); #else /* _AIX */ #include #endif /* _AIX */ #include #include #include #include #include #include #include #include #ifdef HAVE_NET_IF_MEDIA_H # include #endif #include "pcap-int.h" #ifdef HAVE_DAG_API #include "pcap-dag.h" #endif /* HAVE_DAG_API */ #ifdef HAVE_SNF_API #include "pcap-snf.h" #endif /* HAVE_SNF_API */ #ifdef HAVE_OS_PROTO_H #include "os-proto.h" #endif #ifdef BIOCGDLTLIST # if (defined(HAVE_NET_IF_MEDIA_H) && defined(IFM_IEEE80211)) && !defined(__APPLE__) #define HAVE_BSD_IEEE80211 # endif # if defined(__APPLE__) || defined(HAVE_BSD_IEEE80211) static int find_802_11(struct bpf_dltlist *); # ifdef HAVE_BSD_IEEE80211 static int monitor_mode(pcap_t *, int); # endif # if defined(__APPLE__) static void remove_en(pcap_t *); static void remove_802_11(pcap_t *); # endif # endif /* defined(__APPLE__) || defined(HAVE_BSD_IEEE80211) */ #endif /* BIOCGDLTLIST */ /* * We include the OS's , not our "pcap/bpf.h", so we probably * don't get DLT_DOCSIS defined. */ #ifndef DLT_DOCSIS #define DLT_DOCSIS 143 #endif /* * On OS X, we don't even get any of the 802.11-plus-radio-header DLT_'s * defined, even though some of them are used by various Airport drivers. */ #ifndef DLT_PRISM_HEADER #define DLT_PRISM_HEADER 119 #endif #ifndef DLT_AIRONET_HEADER #define DLT_AIRONET_HEADER 120 #endif #ifndef DLT_IEEE802_11_RADIO #define DLT_IEEE802_11_RADIO 127 #endif #ifndef DLT_IEEE802_11_RADIO_AVS #define DLT_IEEE802_11_RADIO_AVS 163 #endif static int pcap_can_set_rfmon_bpf(pcap_t *p); static int pcap_activate_bpf(pcap_t *p); static int pcap_setfilter_bpf(pcap_t *p, struct bpf_program *fp); static int pcap_setdirection_bpf(pcap_t *, pcap_direction_t); static int pcap_set_datalink_bpf(pcap_t *p, int dlt); /* * For zerocopy bpf, the setnonblock/getnonblock routines need to modify * p->md.timeout so we don't call select(2) if the pcap handle is in non- * blocking mode. We preserve the timeout supplied by pcap_open functions * to make sure it does not get clobbered if the pcap handle moves between * blocking and non-blocking mode. */ static int pcap_getnonblock_bpf(pcap_t *p, char *errbuf) { #ifdef HAVE_ZEROCOPY_BPF if (p->md.zerocopy) { /* * Use a negative value for the timeout to represent that the * pcap handle is in non-blocking mode. */ return (p->md.timeout < 0); } #endif return (pcap_getnonblock_fd(p, errbuf)); } static int pcap_setnonblock_bpf(pcap_t *p, int nonblock, char *errbuf) { #ifdef HAVE_ZEROCOPY_BPF if (p->md.zerocopy) { /* * Map each value to the corresponding 2's complement, to * preserve the timeout value provided with pcap_set_timeout. * (from pcap-linux.c). */ if (nonblock) { if (p->md.timeout >= 0) { /* * Timeout is non-negative, so we're not * currently in non-blocking mode; set it * to the 2's complement, to make it * negative, as an indication that we're * in non-blocking mode. */ p->md.timeout = p->md.timeout * -1 - 1; } } else { if (p->md.timeout < 0) { /* * Timeout is negative, so we're currently * in blocking mode; reverse the previous * operation, to make the timeout non-negative * again. */ p->md.timeout = (p->md.timeout + 1) * -1; } } return (0); } #endif return (pcap_setnonblock_fd(p, nonblock, errbuf)); } #ifdef HAVE_ZEROCOPY_BPF /* * Zero-copy BPF buffer routines to check for and acknowledge BPF data in * shared memory buffers. * * pcap_next_zbuf_shm(): Check for a newly available shared memory buffer, * and set up p->buffer and cc to reflect one if available. Notice that if * there was no prior buffer, we select zbuf1 as this will be the first * buffer filled for a fresh BPF session. */ static int pcap_next_zbuf_shm(pcap_t *p, int *cc) { struct bpf_zbuf_header *bzh; if (p->md.zbuffer == p->md.zbuf2 || p->md.zbuffer == NULL) { bzh = (struct bpf_zbuf_header *)p->md.zbuf1; if (bzh->bzh_user_gen != atomic_load_acq_int(&bzh->bzh_kernel_gen)) { p->md.bzh = bzh; p->md.zbuffer = (u_char *)p->md.zbuf1; p->buffer = p->md.zbuffer + sizeof(*bzh); *cc = bzh->bzh_kernel_len; return (1); } } else if (p->md.zbuffer == p->md.zbuf1) { bzh = (struct bpf_zbuf_header *)p->md.zbuf2; if (bzh->bzh_user_gen != atomic_load_acq_int(&bzh->bzh_kernel_gen)) { p->md.bzh = bzh; p->md.zbuffer = (u_char *)p->md.zbuf2; p->buffer = p->md.zbuffer + sizeof(*bzh); *cc = bzh->bzh_kernel_len; return (1); } } *cc = 0; return (0); } /* * pcap_next_zbuf() -- Similar to pcap_next_zbuf_shm(), except wait using * select() for data or a timeout, and possibly force rotation of the buffer * in the event we time out or are in immediate mode. Invoke the shared * memory check before doing system calls in order to avoid doing avoidable * work. */ static int pcap_next_zbuf(pcap_t *p, int *cc) { struct bpf_zbuf bz; struct timeval tv; struct timespec cur; fd_set r_set; int data, r; int expire, tmout; #define TSTOMILLI(ts) (((ts)->tv_sec * 1000) + ((ts)->tv_nsec / 1000000)) /* * Start out by seeing whether anything is waiting by checking the * next shared memory buffer for data. */ data = pcap_next_zbuf_shm(p, cc); if (data) return (data); /* * If a previous sleep was interrupted due to signal delivery, make * sure that the timeout gets adjusted accordingly. This requires * that we analyze when the timeout should be been expired, and * subtract the current time from that. If after this operation, * our timeout is less then or equal to zero, handle it like a * regular timeout. */ tmout = p->md.timeout; if (tmout) (void) clock_gettime(CLOCK_MONOTONIC, &cur); if (p->md.interrupted && p->md.timeout) { expire = TSTOMILLI(&p->md.firstsel) + p->md.timeout; tmout = expire - TSTOMILLI(&cur); #undef TSTOMILLI if (tmout <= 0) { p->md.interrupted = 0; data = pcap_next_zbuf_shm(p, cc); if (data) return (data); if (ioctl(p->fd, BIOCROTZBUF, &bz) < 0) { (void) snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCROTZBUF: %s", strerror(errno)); return (PCAP_ERROR); } return (pcap_next_zbuf_shm(p, cc)); } } /* * No data in the buffer, so must use select() to wait for data or * the next timeout. Note that we only call select if the handle * is in blocking mode. */ if (p->md.timeout >= 0) { FD_ZERO(&r_set); FD_SET(p->fd, &r_set); if (tmout != 0) { tv.tv_sec = tmout / 1000; tv.tv_usec = (tmout * 1000) % 1000000; } r = select(p->fd + 1, &r_set, NULL, NULL, p->md.timeout != 0 ? &tv : NULL); if (r < 0 && errno == EINTR) { if (!p->md.interrupted && p->md.timeout) { p->md.interrupted = 1; p->md.firstsel = cur; } return (0); } else if (r < 0) { (void) snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "select: %s", strerror(errno)); return (PCAP_ERROR); } } p->md.interrupted = 0; /* * Check again for data, which may exist now that we've either been * woken up as a result of data or timed out. Try the "there's data" * case first since it doesn't require a system call. */ data = pcap_next_zbuf_shm(p, cc); if (data) return (data); /* * Try forcing a buffer rotation to dislodge timed out or immediate * data. */ if (ioctl(p->fd, BIOCROTZBUF, &bz) < 0) { (void) snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCROTZBUF: %s", strerror(errno)); return (PCAP_ERROR); } return (pcap_next_zbuf_shm(p, cc)); } /* * Notify kernel that we are done with the buffer. We don't reset zbuffer so * that we know which buffer to use next time around. */ static int pcap_ack_zbuf(pcap_t *p) { atomic_store_rel_int(&p->md.bzh->bzh_user_gen, p->md.bzh->bzh_kernel_gen); p->md.bzh = NULL; p->buffer = NULL; return (0); } #endif /* HAVE_ZEROCOPY_BPF */ pcap_t * pcap_create(const char *device, char *ebuf) { pcap_t *p; #ifdef HAVE_DAG_API if (strstr(device, "dag")) return (dag_create(device, ebuf)); #endif /* HAVE_DAG_API */ #ifdef HAVE_SNF_API if (strstr(device, "snf")) return (snf_create(device, ebuf)); #endif /* HAVE_SNF_API */ p = pcap_create_common(device, ebuf); if (p == NULL) return (NULL); p->activate_op = pcap_activate_bpf; p->can_set_rfmon_op = pcap_can_set_rfmon_bpf; return (p); } /* * On success, returns a file descriptor for a BPF device. * On failure, returns a PCAP_ERROR_ value, and sets p->errbuf. */ static int bpf_open(pcap_t *p) { int fd; #ifdef HAVE_CLONING_BPF static const char device[] = "/dev/bpf"; #else int n = 0; char device[sizeof "/dev/bpf0000000000"]; #endif #ifdef _AIX /* * Load the bpf driver, if it isn't already loaded, * and create the BPF device entries, if they don't * already exist. */ if (bpf_load(p->errbuf) == PCAP_ERROR) return (PCAP_ERROR); #endif #ifdef HAVE_CLONING_BPF if ((fd = open(device, O_RDWR)) == -1 && (errno != EACCES || (fd = open(device, O_RDONLY)) == -1)) { if (errno == EACCES) fd = PCAP_ERROR_PERM_DENIED; else fd = PCAP_ERROR; snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "(cannot open device) %s: %s", device, pcap_strerror(errno)); } #else /* * Go through all the minors and find one that isn't in use. */ do { (void)snprintf(device, sizeof(device), "/dev/bpf%d", n++); /* * Initially try a read/write open (to allow the inject * method to work). If that fails due to permission * issues, fall back to read-only. This allows a * non-root user to be granted specific access to pcap * capabilities via file permissions. * * XXX - we should have an API that has a flag that * controls whether to open read-only or read-write, * so that denial of permission to send (or inability * to send, if sending packets isn't supported on * the device in question) can be indicated at open * time. */ fd = open(device, O_RDWR); if (fd == -1 && errno == EACCES) fd = open(device, O_RDONLY); } while (fd < 0 && errno == EBUSY); /* * XXX better message for all minors used */ if (fd < 0) { switch (errno) { case ENOENT: fd = PCAP_ERROR; if (n == 1) { /* * /dev/bpf0 doesn't exist, which * means we probably have no BPF * devices. */ snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "(there are no BPF devices)"); } else { /* * We got EBUSY on at least one * BPF device, so we have BPF * devices, but all the ones * that exist are busy. */ snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "(all BPF devices are busy)"); } break; case EACCES: /* * Got EACCES on the last device we tried, * and EBUSY on all devices before that, * if any. */ fd = PCAP_ERROR_PERM_DENIED; snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "(cannot open BPF device) %s: %s", device, pcap_strerror(errno)); break; default: /* * Some other problem. */ fd = PCAP_ERROR; snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "(cannot open BPF device) %s: %s", device, pcap_strerror(errno)); break; } } #endif return (fd); } #ifdef BIOCGDLTLIST static int get_dlt_list(int fd, int v, struct bpf_dltlist *bdlp, char *ebuf) { memset(bdlp, 0, sizeof(*bdlp)); if (ioctl(fd, BIOCGDLTLIST, (caddr_t)bdlp) == 0) { u_int i; int is_ethernet; bdlp->bfl_list = (u_int *) malloc(sizeof(u_int) * (bdlp->bfl_len + 1)); if (bdlp->bfl_list == NULL) { (void)snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); return (PCAP_ERROR); } if (ioctl(fd, BIOCGDLTLIST, (caddr_t)bdlp) < 0) { (void)snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCGDLTLIST: %s", pcap_strerror(errno)); free(bdlp->bfl_list); return (PCAP_ERROR); } /* * OK, for real Ethernet devices, add DLT_DOCSIS to the * list, so that an application can let you choose it, * in case you're capturing DOCSIS traffic that a Cisco * Cable Modem Termination System is putting out onto * an Ethernet (it doesn't put an Ethernet header onto * the wire, it puts raw DOCSIS frames out on the wire * inside the low-level Ethernet framing). * * A "real Ethernet device" is defined here as a device * that has a link-layer type of DLT_EN10MB and that has * no alternate link-layer types; that's done to exclude * 802.11 interfaces (which might or might not be the * right thing to do, but I suspect it is - Ethernet <-> * 802.11 bridges would probably badly mishandle frames * that don't have Ethernet headers). * * On Solaris with BPF, Ethernet devices also offer * DLT_IPNET, so we, if DLT_IPNET is defined, we don't * treat it as an indication that the device isn't an * Ethernet. */ if (v == DLT_EN10MB) { is_ethernet = 1; for (i = 0; i < bdlp->bfl_len; i++) { if (bdlp->bfl_list[i] != DLT_EN10MB #ifdef DLT_IPNET && bdlp->bfl_list[i] != DLT_IPNET #endif ) { is_ethernet = 0; break; } } if (is_ethernet) { /* * We reserved one more slot at the end of * the list. */ bdlp->bfl_list[bdlp->bfl_len] = DLT_DOCSIS; bdlp->bfl_len++; } } } else { /* * EINVAL just means "we don't support this ioctl on * this device"; don't treat it as an error. */ if (errno != EINVAL) { (void)snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCGDLTLIST: %s", pcap_strerror(errno)); return (PCAP_ERROR); } } return (0); } #endif static int pcap_can_set_rfmon_bpf(pcap_t *p) { #if defined(__APPLE__) struct utsname osinfo; struct ifreq ifr; int fd; #ifdef BIOCGDLTLIST struct bpf_dltlist bdl; #endif /* * The joys of monitor mode on OS X. * * Prior to 10.4, it's not supported at all. * * In 10.4, if adapter enN supports monitor mode, there's a * wltN adapter corresponding to it; you open it, instead of * enN, to get monitor mode. You get whatever link-layer * headers it supplies. * * In 10.5, and, we assume, later releases, if adapter enN * supports monitor mode, it offers, among its selectable * DLT_ values, values that let you get the 802.11 header; * selecting one of those values puts the adapter into monitor * mode (i.e., you can't get 802.11 headers except in monitor * mode, and you can't get Ethernet headers in monitor mode). */ if (uname(&osinfo) == -1) { /* * Can't get the OS version; just say "no". */ return (0); } /* * We assume osinfo.sysname is "Darwin", because * __APPLE__ is defined. We just check the version. */ if (osinfo.release[0] < '8' && osinfo.release[1] == '.') { /* * 10.3 (Darwin 7.x) or earlier. * Monitor mode not supported. */ return (0); } if (osinfo.release[0] == '8' && osinfo.release[1] == '.') { /* * 10.4 (Darwin 8.x). s/en/wlt/, and check * whether the device exists. */ if (strncmp(p->opt.source, "en", 2) != 0) { /* * Not an enN device; no monitor mode. */ return (0); } fd = socket(AF_INET, SOCK_DGRAM, 0); if (fd == -1) { (void)snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "socket: %s", pcap_strerror(errno)); return (PCAP_ERROR); } strlcpy(ifr.ifr_name, "wlt", sizeof(ifr.ifr_name)); strlcat(ifr.ifr_name, p->opt.source + 2, sizeof(ifr.ifr_name)); if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) < 0) { /* * No such device? */ close(fd); return (0); } close(fd); return (1); } #ifdef BIOCGDLTLIST /* * Everything else is 10.5 or later; for those, * we just open the enN device, and check whether * we have any 802.11 devices. * * First, open a BPF device. */ fd = bpf_open(p); if (fd < 0) return (fd); /* fd is the appropriate error code */ /* * Now bind to the device. */ (void)strncpy(ifr.ifr_name, p->opt.source, sizeof(ifr.ifr_name)); if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) < 0) { switch (errno) { case ENXIO: /* * There's no such device. */ close(fd); return (PCAP_ERROR_NO_SUCH_DEVICE); case 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. */ close(fd); return (PCAP_ERROR_IFACE_NOT_UP); default: snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETIF: %s: %s", p->opt.source, pcap_strerror(errno)); close(fd); return (PCAP_ERROR); } } /* * We know the default link type -- now determine all the DLTs * this interface supports. If this fails with EINVAL, it's * not fatal; we just don't get to use the feature later. * (We don't care about DLT_DOCSIS, so we pass DLT_NULL * as the default DLT for this adapter.) */ if (get_dlt_list(fd, DLT_NULL, &bdl, p->errbuf) == PCAP_ERROR) { close(fd); return (PCAP_ERROR); } if (find_802_11(&bdl) != -1) { /* * We have an 802.11 DLT, so we can set monitor mode. */ free(bdl.bfl_list); close(fd); return (1); } free(bdl.bfl_list); #endif /* BIOCGDLTLIST */ return (0); #elif defined(HAVE_BSD_IEEE80211) int ret; ret = monitor_mode(p, 0); if (ret == PCAP_ERROR_RFMON_NOTSUP) return (0); /* not an error, just a "can't do" */ if (ret == 0) return (1); /* success */ return (ret); #else return (0); #endif } static int pcap_stats_bpf(pcap_t *p, struct pcap_stat *ps) { struct bpf_stat s; /* * "ps_recv" counts packets handed to the filter, not packets * that passed the filter. This includes packets later dropped * because we ran out of buffer space. * * "ps_drop" counts packets dropped inside the BPF device * because we ran out of buffer space. It doesn't count * packets dropped by the interface driver. It counts * only packets that passed the filter. * * Both statistics include packets not yet read from the kernel * by libpcap, and thus not yet seen by the application. */ if (ioctl(p->fd, BIOCGSTATS, (caddr_t)&s) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCGSTATS: %s", pcap_strerror(errno)); return (PCAP_ERROR); } ps->ps_recv = s.bs_recv; ps->ps_drop = s.bs_drop; ps->ps_ifdrop = 0; return (0); } static int pcap_read_bpf(pcap_t *p, int cnt, pcap_handler callback, u_char *user) { int cc; int n = 0; register u_char *bp, *ep; u_char *datap; #ifdef PCAP_FDDIPAD register int pad; #endif #ifdef HAVE_ZEROCOPY_BPF int i; #endif again: /* * Has "pcap_breakloop()" been called? */ if (p->break_loop) { /* * Yes - clear the flag that indicates that it * has, and return PCAP_ERROR_BREAK to indicate * that we were told to break out of the loop. */ p->break_loop = 0; return (PCAP_ERROR_BREAK); } cc = p->cc; if (p->cc == 0) { /* * When reading without zero-copy from a file descriptor, we * use a single buffer and return a length of data in the * buffer. With zero-copy, we update the p->buffer pointer * to point at whatever underlying buffer contains the next * data and update cc to reflect the data found in the * buffer. */ #ifdef HAVE_ZEROCOPY_BPF if (p->md.zerocopy) { if (p->buffer != NULL) pcap_ack_zbuf(p); i = pcap_next_zbuf(p, &cc); if (i == 0) goto again; if (i < 0) return (PCAP_ERROR); } else #endif { cc = read(p->fd, (char *)p->buffer, p->bufsize); } if (cc < 0) { /* Don't choke when we get ptraced */ switch (errno) { case EINTR: goto again; #ifdef _AIX case EFAULT: /* * Sigh. More AIX wonderfulness. * * For some unknown reason the uiomove() * operation in the bpf kernel extension * used to copy the buffer into user * space sometimes returns EFAULT. I have * no idea why this is the case given that * a kernel debugger shows the user buffer * is correct. This problem appears to * be mostly mitigated by the memset of * the buffer before it is first used. * Very strange.... Shaun Clowes * * In any case this means that we shouldn't * treat EFAULT as a fatal error; as we * don't have an API for returning * a "some packets were dropped since * the last packet you saw" indication, * we just ignore EFAULT and keep reading. */ goto again; #endif case EWOULDBLOCK: return (0); case ENXIO: /* * The device on which we're capturing * went away. * * XXX - we should really return * PCAP_ERROR_IFACE_NOT_UP, but * pcap_dispatch() etc. aren't * defined to retur that. */ snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "The interface went down"); return (PCAP_ERROR); #if defined(sun) && !defined(BSD) && !defined(__svr4__) && !defined(__SVR4) /* * Due to a SunOS bug, after 2^31 bytes, the kernel * file offset overflows and read fails with EINVAL. * The lseek() to 0 will fix things. */ case EINVAL: if (lseek(p->fd, 0L, SEEK_CUR) + p->bufsize < 0) { (void)lseek(p->fd, 0L, SEEK_SET); goto again; } /* fall through */ #endif } snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "read: %s", pcap_strerror(errno)); return (PCAP_ERROR); } bp = p->buffer; } else bp = p->bp; /* * Loop through each packet. */ #define bhp ((struct bpf_hdr *)bp) ep = bp + cc; #ifdef PCAP_FDDIPAD pad = p->fddipad; #endif while (bp < ep) { register int caplen, hdrlen; /* * Has "pcap_breakloop()" been called? * If so, return immediately - if we haven't read any * packets, clear the flag and return PCAP_ERROR_BREAK * to indicate that we were told to break out of the loop, * otherwise leave the flag set, so that the *next* call * will break out of the loop without having read any * packets, and return the number of packets we've * processed so far. */ if (p->break_loop) { p->bp = bp; p->cc = ep - bp; /* * ep is set based on the return value of read(), * but read() from a BPF device doesn't necessarily * return a value that's a multiple of the alignment * value for BPF_WORDALIGN(). However, whenever we * increment bp, we round up the increment value by * a value rounded up by BPF_WORDALIGN(), so we * could increment bp past ep after processing the * last packet in the buffer. * * We treat ep < bp as an indication that this * happened, and just set p->cc to 0. */ if (p->cc < 0) p->cc = 0; if (n == 0) { p->break_loop = 0; return (PCAP_ERROR_BREAK); } else return (n); } caplen = bhp->bh_caplen; hdrlen = bhp->bh_hdrlen; datap = bp + hdrlen; /* * Short-circuit evaluation: if using BPF filter * in kernel, no need to do it now - we already know * the packet passed the filter. * #ifdef PCAP_FDDIPAD * Note: the filter code was generated assuming * that p->fddipad was the amount of padding * before the header, as that's what's required * in the kernel, so we run the filter before * skipping that padding. #endif */ if (p->md.use_bpf || bpf_filter(p->fcode.bf_insns, datap, bhp->bh_datalen, caplen)) { struct pcap_pkthdr pkthdr; pkthdr.ts.tv_sec = bhp->bh_tstamp.tv_sec; #ifdef _AIX /* * AIX's BPF returns seconds/nanoseconds time * stamps, not seconds/microseconds time stamps. */ pkthdr.ts.tv_usec = bhp->bh_tstamp.tv_usec/1000; #else pkthdr.ts.tv_usec = bhp->bh_tstamp.tv_usec; #endif #ifdef PCAP_FDDIPAD if (caplen > pad) pkthdr.caplen = caplen - pad; else pkthdr.caplen = 0; if (bhp->bh_datalen > pad) pkthdr.len = bhp->bh_datalen - pad; else pkthdr.len = 0; datap += pad; #else pkthdr.caplen = caplen; pkthdr.len = bhp->bh_datalen; #endif (*callback)(user, &pkthdr, datap); bp += BPF_WORDALIGN(caplen + hdrlen); if (++n >= cnt && cnt > 0) { p->bp = bp; p->cc = ep - bp; /* * See comment above about p->cc < 0. */ if (p->cc < 0) p->cc = 0; return (n); } } else { /* * Skip this packet. */ bp += BPF_WORDALIGN(caplen + hdrlen); } } #undef bhp p->cc = 0; return (n); } static int pcap_inject_bpf(pcap_t *p, const void *buf, size_t size) { int ret; ret = write(p->fd, buf, size); #ifdef __APPLE__ if (ret == -1 && errno == EAFNOSUPPORT) { /* * In Mac OS X, there's a bug wherein setting the * BIOCSHDRCMPLT flag causes writes to fail; see, * for example: * * http://cerberus.sourcefire.com/~jeff/archives/patches/macosx/BIOCSHDRCMPLT-10.3.3.patch * * So, if, on OS X, we get EAFNOSUPPORT from the write, we * assume it's due to that bug, and turn off that flag * and try again. If we succeed, it either means that * somebody applied the fix from that URL, or other patches * for that bug from * * http://cerberus.sourcefire.com/~jeff/archives/patches/macosx/ * * and are running a Darwin kernel with those fixes, or * that Apple fixed the problem in some OS X release. */ u_int spoof_eth_src = 0; if (ioctl(p->fd, BIOCSHDRCMPLT, &spoof_eth_src) == -1) { (void)snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: can't turn off BIOCSHDRCMPLT: %s", pcap_strerror(errno)); return (PCAP_ERROR); } /* * Now try the write again. */ ret = write(p->fd, buf, size); } #endif /* __APPLE__ */ if (ret == -1) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s", pcap_strerror(errno)); return (PCAP_ERROR); } return (ret); } #ifdef _AIX static int bpf_odminit(char *errbuf) { char *errstr; if (odm_initialize() == -1) { if (odm_err_msg(odmerrno, &errstr) == -1) errstr = "Unknown error"; snprintf(errbuf, PCAP_ERRBUF_SIZE, "bpf_load: odm_initialize failed: %s", errstr); return (PCAP_ERROR); } if ((odmlockid = odm_lock("/etc/objrepos/config_lock", ODM_WAIT)) == -1) { if (odm_err_msg(odmerrno, &errstr) == -1) errstr = "Unknown error"; snprintf(errbuf, PCAP_ERRBUF_SIZE, "bpf_load: odm_lock of /etc/objrepos/config_lock failed: %s", errstr); (void)odm_terminate(); return (PCAP_ERROR); } return (0); } static int bpf_odmcleanup(char *errbuf) { char *errstr; if (odm_unlock(odmlockid) == -1) { if (errbuf != NULL) { if (odm_err_msg(odmerrno, &errstr) == -1) errstr = "Unknown error"; snprintf(errbuf, PCAP_ERRBUF_SIZE, "bpf_load: odm_unlock failed: %s", errstr); } return (PCAP_ERROR); } if (odm_terminate() == -1) { if (errbuf != NULL) { if (odm_err_msg(odmerrno, &errstr) == -1) errstr = "Unknown error"; snprintf(errbuf, PCAP_ERRBUF_SIZE, "bpf_load: odm_terminate failed: %s", errstr); } return (PCAP_ERROR); } return (0); } static int bpf_load(char *errbuf) { long major; int *minors; int numminors, i, rc; char buf[1024]; struct stat sbuf; struct bpf_config cfg_bpf; struct cfg_load cfg_ld; struct cfg_kmod cfg_km; /* * This is very very close to what happens in the real implementation * but I've fixed some (unlikely) bug situations. */ if (bpfloadedflag) return (0); if (bpf_odminit(errbuf) == PCAP_ERROR) return (PCAP_ERROR); major = genmajor(BPF_NAME); if (major == -1) { snprintf(errbuf, PCAP_ERRBUF_SIZE, "bpf_load: genmajor failed: %s", pcap_strerror(errno)); (void)bpf_odmcleanup(NULL); return (PCAP_ERROR); } minors = getminor(major, &numminors, BPF_NAME); if (!minors) { minors = genminor("bpf", major, 0, BPF_MINORS, 1, 1); if (!minors) { snprintf(errbuf, PCAP_ERRBUF_SIZE, "bpf_load: genminor failed: %s", pcap_strerror(errno)); (void)bpf_odmcleanup(NULL); return (PCAP_ERROR); } } if (bpf_odmcleanup(errbuf) == PCAP_ERROR) return (PCAP_ERROR); rc = stat(BPF_NODE "0", &sbuf); if (rc == -1 && errno != ENOENT) { snprintf(errbuf, PCAP_ERRBUF_SIZE, "bpf_load: can't stat %s: %s", BPF_NODE "0", pcap_strerror(errno)); return (PCAP_ERROR); } if (rc == -1 || getmajor(sbuf.st_rdev) != major) { for (i = 0; i < BPF_MINORS; i++) { sprintf(buf, "%s%d", BPF_NODE, i); unlink(buf); if (mknod(buf, S_IRUSR | S_IFCHR, domakedev(major, i)) == -1) { snprintf(errbuf, PCAP_ERRBUF_SIZE, "bpf_load: can't mknod %s: %s", buf, pcap_strerror(errno)); return (PCAP_ERROR); } } } /* Check if the driver is loaded */ memset(&cfg_ld, 0x0, sizeof(cfg_ld)); cfg_ld.path = buf; sprintf(cfg_ld.path, "%s/%s", DRIVER_PATH, BPF_NAME); if ((sysconfig(SYS_QUERYLOAD, (void *)&cfg_ld, sizeof(cfg_ld)) == -1) || (cfg_ld.kmid == 0)) { /* Driver isn't loaded, load it now */ if (sysconfig(SYS_SINGLELOAD, (void *)&cfg_ld, sizeof(cfg_ld)) == -1) { snprintf(errbuf, PCAP_ERRBUF_SIZE, "bpf_load: could not load driver: %s", strerror(errno)); return (PCAP_ERROR); } } /* Configure the driver */ cfg_km.cmd = CFG_INIT; cfg_km.kmid = cfg_ld.kmid; cfg_km.mdilen = sizeof(cfg_bpf); cfg_km.mdiptr = (void *)&cfg_bpf; for (i = 0; i < BPF_MINORS; i++) { cfg_bpf.devno = domakedev(major, i); if (sysconfig(SYS_CFGKMOD, (void *)&cfg_km, sizeof(cfg_km)) == -1) { snprintf(errbuf, PCAP_ERRBUF_SIZE, "bpf_load: could not configure driver: %s", strerror(errno)); return (PCAP_ERROR); } } bpfloadedflag = 1; return (0); } #endif /* * Turn off rfmon mode if necessary. */ static void pcap_cleanup_bpf(pcap_t *p) { #ifdef HAVE_BSD_IEEE80211 int sock; struct ifmediareq req; struct ifreq ifr; #endif if (p->md.must_do_on_close != 0) { /* * There's something we have to do when closing this * pcap_t. */ #ifdef HAVE_BSD_IEEE80211 if (p->md.must_do_on_close & 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. */ sock = socket(AF_INET, SOCK_DGRAM, 0); if (sock == -1) { fprintf(stderr, "Can't restore interface flags (socket() failed: %s).\n" "Please adjust manually.\n", strerror(errno)); } else { memset(&req, 0, sizeof(req)); strncpy(req.ifm_name, p->md.device, sizeof(req.ifm_name)); if (ioctl(sock, SIOCGIFMEDIA, &req) < 0) { fprintf(stderr, "Can't restore interface flags (SIOCGIFMEDIA failed: %s).\n" "Please adjust manually.\n", strerror(errno)); } else { if (req.ifm_current & IFM_IEEE80211_MONITOR) { /* * Rfmon mode is currently on; * turn it off. */ memset(&ifr, 0, sizeof(ifr)); (void)strncpy(ifr.ifr_name, p->md.device, sizeof(ifr.ifr_name)); ifr.ifr_media = req.ifm_current & ~IFM_IEEE80211_MONITOR; if (ioctl(sock, SIOCSIFMEDIA, &ifr) == -1) { fprintf(stderr, "Can't restore interface flags (SIOCSIFMEDIA failed: %s).\n" "Please adjust manually.\n", strerror(errno)); } } } close(sock); } } #endif /* HAVE_BSD_IEEE80211 */ /* * 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(p); p->md.must_do_on_close = 0; } #ifdef HAVE_ZEROCOPY_BPF if (p->md.zerocopy) { /* * Delete the mappings. Note that p->buffer gets * initialized to one of the mmapped regions in * this case, so do not try and free it directly; * null it out so that pcap_cleanup_live_common() * doesn't try to free it. */ if (p->md.zbuf1 != MAP_FAILED && p->md.zbuf1 != NULL) (void) munmap(p->md.zbuf1, p->md.zbufsize); if (p->md.zbuf2 != MAP_FAILED && p->md.zbuf2 != NULL) (void) munmap(p->md.zbuf2, p->md.zbufsize); p->buffer = NULL; } #endif if (p->md.device != NULL) { free(p->md.device); p->md.device = NULL; } pcap_cleanup_live_common(p); } static int check_setif_failure(pcap_t *p, int error) { #ifdef __APPLE__ int fd; struct ifreq ifr; int err; #endif if (error == ENXIO) { /* * No such device exists. */ #ifdef __APPLE__ if (p->opt.rfmon && strncmp(p->opt.source, "wlt", 3) == 0) { /* * Monitor mode was requested, and we're trying * to open a "wltN" device. Assume that this * is 10.4 and that we were asked to open an * "enN" device; if that device exists, return * "monitor mode not supported on the device". */ fd = socket(AF_INET, SOCK_DGRAM, 0); if (fd != -1) { strlcpy(ifr.ifr_name, "en", sizeof(ifr.ifr_name)); strlcat(ifr.ifr_name, p->opt.source + 3, sizeof(ifr.ifr_name)); if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) < 0) { /* * We assume this failed because * the underlying device doesn't * exist. */ err = PCAP_ERROR_NO_SUCH_DEVICE; snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFFLAGS on %s failed: %s", ifr.ifr_name, pcap_strerror(errno)); } else { /* * The underlying "enN" device * exists, but there's no * corresponding "wltN" device; * that means that the "enN" * device doesn't support * monitor mode, probably because * it's an Ethernet device rather * than a wireless device. */ err = PCAP_ERROR_RFMON_NOTSUP; } close(fd); } else { /* * We can't find out whether there's * an underlying "enN" device, so * just report "no such device". */ err = PCAP_ERROR_NO_SUCH_DEVICE; snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "socket() failed: %s", pcap_strerror(errno)); } return (err); } #endif /* * No such device. */ snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETIF failed: %s", pcap_strerror(errno)); return (PCAP_ERROR_NO_SUCH_DEVICE); } else 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 { /* * Some other error; fill in the error string, and * return PCAP_ERROR. */ snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETIF: %s: %s", p->opt.source, pcap_strerror(errno)); return (PCAP_ERROR); } } /* * Default capture buffer size. * 32K isn't very much for modern machines with fast networks; we * pick .5M, as that's the maximum on at least some systems with BPF. */ #define DEFAULT_BUFSIZE 524288 static int pcap_activate_bpf(pcap_t *p) { int status = 0; int fd; struct ifreq ifr; struct bpf_version bv; #ifdef __APPLE__ int sockfd; char *wltdev = NULL; #endif #ifdef BIOCGDLTLIST struct bpf_dltlist bdl; #if defined(__APPLE__) || defined(HAVE_BSD_IEEE80211) int new_dlt; #endif #endif /* BIOCGDLTLIST */ #if defined(BIOCGHDRCMPLT) && defined(BIOCSHDRCMPLT) u_int spoof_eth_src = 1; #endif u_int v; struct bpf_insn total_insn; struct bpf_program total_prog; struct utsname osinfo; int have_osinfo = 0; #ifdef HAVE_ZEROCOPY_BPF struct bpf_zbuf bz; u_int bufmode, zbufmax; #endif fd = bpf_open(p); if (fd < 0) { status = fd; goto bad; } p->fd = fd; if (ioctl(fd, BIOCVERSION, (caddr_t)&bv) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCVERSION: %s", pcap_strerror(errno)); status = PCAP_ERROR; goto bad; } if (bv.bv_major != BPF_MAJOR_VERSION || bv.bv_minor < BPF_MINOR_VERSION) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "kernel bpf filter out of date"); status = PCAP_ERROR; goto bad; } p->md.device = strdup(p->opt.source); if (p->md.device == NULL) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "strdup: %s", pcap_strerror(errno)); status = PCAP_ERROR; goto bad; } /* * Attempt to find out the version of the OS on which we're running. */ if (uname(&osinfo) == 0) have_osinfo = 1; #ifdef __APPLE__ /* * See comment in pcap_can_set_rfmon_bpf() for an explanation * of why we check the version number. */ if (p->opt.rfmon) { if (have_osinfo) { /* * We assume osinfo.sysname is "Darwin", because * __APPLE__ is defined. We just check the version. */ if (osinfo.release[0] < '8' && osinfo.release[1] == '.') { /* * 10.3 (Darwin 7.x) or earlier. */ status = PCAP_ERROR_RFMON_NOTSUP; goto bad; } if (osinfo.release[0] == '8' && osinfo.release[1] == '.') { /* * 10.4 (Darwin 8.x). s/en/wlt/ */ if (strncmp(p->opt.source, "en", 2) != 0) { /* * Not an enN device; check * whether the device even exists. */ sockfd = socket(AF_INET, SOCK_DGRAM, 0); if (sockfd != -1) { strlcpy(ifr.ifr_name, p->opt.source, sizeof(ifr.ifr_name)); if (ioctl(sockfd, SIOCGIFFLAGS, (char *)&ifr) < 0) { /* * We assume this * failed because * the underlying * device doesn't * exist. */ status = PCAP_ERROR_NO_SUCH_DEVICE; snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFFLAGS failed: %s", pcap_strerror(errno)); } else status = PCAP_ERROR_RFMON_NOTSUP; close(sockfd); } else { /* * We can't find out whether * the device exists, so just * report "no such device". */ status = PCAP_ERROR_NO_SUCH_DEVICE; snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "socket() failed: %s", pcap_strerror(errno)); } goto bad; } wltdev = malloc(strlen(p->opt.source) + 2); if (wltdev == NULL) { (void)snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); status = PCAP_ERROR; goto bad; } strcpy(wltdev, "wlt"); strcat(wltdev, p->opt.source + 2); free(p->opt.source); p->opt.source = wltdev; } /* * Everything else is 10.5 or later; for those, * we just open the enN device, and set the DLT. */ } } #endif /* __APPLE__ */ #ifdef HAVE_ZEROCOPY_BPF /* * If the BPF extension to set buffer mode is present, try setting * the mode to zero-copy. If that fails, use regular buffering. If * it succeeds but other setup fails, return an error to the user. */ bufmode = BPF_BUFMODE_ZBUF; if (ioctl(fd, BIOCSETBUFMODE, (caddr_t)&bufmode) == 0) { /* * We have zerocopy BPF; use it. */ p->md.zerocopy = 1; /* * How to pick a buffer size: first, query the maximum buffer * size supported by zero-copy. This also lets us quickly * determine whether the kernel generally supports zero-copy. * Then, if a buffer size was specified, use that, otherwise * query the default buffer size, which reflects kernel * policy for a desired default. Round to the nearest page * size. */ if (ioctl(fd, BIOCGETZMAX, (caddr_t)&zbufmax) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCGETZMAX: %s", pcap_strerror(errno)); goto bad; } if (p->opt.buffer_size != 0) { /* * A buffer size was explicitly specified; use it. */ v = p->opt.buffer_size; } else { if ((ioctl(fd, BIOCGBLEN, (caddr_t)&v) < 0) || v < DEFAULT_BUFSIZE) v = DEFAULT_BUFSIZE; } #ifndef roundup #define roundup(x, y) ((((x)+((y)-1))/(y))*(y)) /* to any y */ #endif p->md.zbufsize = roundup(v, getpagesize()); if (p->md.zbufsize > zbufmax) p->md.zbufsize = zbufmax; p->md.zbuf1 = mmap(NULL, p->md.zbufsize, PROT_READ | PROT_WRITE, MAP_ANON, -1, 0); p->md.zbuf2 = mmap(NULL, p->md.zbufsize, PROT_READ | PROT_WRITE, MAP_ANON, -1, 0); if (p->md.zbuf1 == MAP_FAILED || p->md.zbuf2 == MAP_FAILED) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "mmap: %s", pcap_strerror(errno)); goto bad; } bzero(&bz, sizeof(bz)); bz.bz_bufa = p->md.zbuf1; bz.bz_bufb = p->md.zbuf2; bz.bz_buflen = p->md.zbufsize; if (ioctl(fd, BIOCSETZBUF, (caddr_t)&bz) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETZBUF: %s", pcap_strerror(errno)); goto bad; } (void)strncpy(ifr.ifr_name, p->opt.source, sizeof(ifr.ifr_name)); if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETIF: %s: %s", p->opt.source, pcap_strerror(errno)); goto bad; } v = p->md.zbufsize - sizeof(struct bpf_zbuf_header); } else #endif { /* * We don't have zerocopy BPF. * Set the buffer size. */ if (p->opt.buffer_size != 0) { /* * A buffer size was explicitly specified; use it. */ if (ioctl(fd, BIOCSBLEN, (caddr_t)&p->opt.buffer_size) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSBLEN: %s: %s", p->opt.source, pcap_strerror(errno)); status = PCAP_ERROR; goto bad; } /* * Now bind to the device. */ (void)strncpy(ifr.ifr_name, p->opt.source, sizeof(ifr.ifr_name)); if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) < 0) { status = check_setif_failure(p, errno); goto bad; } } else { /* * No buffer size was explicitly specified. * * Try finding a good size for the buffer; * DEFAULT_BUFSIZE may be too big, so keep * cutting it in half until we find a size * that works, or run out of sizes to try. * If the default is larger, don't make it smaller. */ if ((ioctl(fd, BIOCGBLEN, (caddr_t)&v) < 0) || v < DEFAULT_BUFSIZE) v = DEFAULT_BUFSIZE; for ( ; v != 0; v >>= 1) { /* * Ignore the return value - this is because the * call fails on BPF systems that don't have * kernel malloc. And if the call fails, it's * no big deal, we just continue to use the * standard buffer size. */ (void) ioctl(fd, BIOCSBLEN, (caddr_t)&v); (void)strncpy(ifr.ifr_name, p->opt.source, sizeof(ifr.ifr_name)); if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) >= 0) break; /* that size worked; we're done */ if (errno != ENOBUFS) { status = check_setif_failure(p, errno); goto bad; } } if (v == 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSBLEN: %s: No buffer size worked", p->opt.source); status = PCAP_ERROR; goto bad; } } } /* Get the data link layer type. */ if (ioctl(fd, BIOCGDLT, (caddr_t)&v) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCGDLT: %s", pcap_strerror(errno)); status = PCAP_ERROR; goto bad; } #ifdef _AIX /* * AIX's BPF returns IFF_ types, not DLT_ types, in BIOCGDLT. */ switch (v) { case IFT_ETHER: case IFT_ISO88023: v = DLT_EN10MB; break; case IFT_FDDI: v = DLT_FDDI; break; case IFT_ISO88025: v = DLT_IEEE802; break; case IFT_LOOP: v = DLT_NULL; break; default: /* * We don't know what to map this to yet. */ snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "unknown interface type %u", v); status = PCAP_ERROR; goto bad; } #endif #if _BSDI_VERSION - 0 >= 199510 /* The SLIP and PPP link layer header changed in BSD/OS 2.1 */ switch (v) { case DLT_SLIP: v = DLT_SLIP_BSDOS; break; case DLT_PPP: v = DLT_PPP_BSDOS; break; case 11: /*DLT_FR*/ v = DLT_FRELAY; break; case 12: /*DLT_C_HDLC*/ v = DLT_CHDLC; break; } #endif #ifdef BIOCGDLTLIST /* * We know the default link type -- now determine all the DLTs * this interface supports. If this fails with EINVAL, it's * not fatal; we just don't get to use the feature later. */ if (get_dlt_list(fd, v, &bdl, p->errbuf) == -1) { status = PCAP_ERROR; goto bad; } p->dlt_count = bdl.bfl_len; p->dlt_list = bdl.bfl_list; #ifdef __APPLE__ /* * Monitor mode fun, continued. * * For 10.5 and, we're assuming, later releases, as noted above, * 802.1 adapters that support monitor mode offer both DLT_EN10MB, * DLT_IEEE802_11, and possibly some 802.11-plus-radio-information * DLT_ value. Choosing one of the 802.11 DLT_ values will turn * monitor mode on. * * Therefore, if the user asked for monitor mode, we filter out * the DLT_EN10MB value, as you can't get that in monitor mode, * and, if the user didn't ask for monitor mode, we filter out * the 802.11 DLT_ values, because selecting those will turn * monitor mode on. Then, for monitor mode, if an 802.11-plus- * radio DLT_ value is offered, we try to select that, otherwise * we try to select DLT_IEEE802_11. */ if (have_osinfo) { if (isdigit((unsigned)osinfo.release[0]) && (osinfo.release[0] == '9' || isdigit((unsigned)osinfo.release[1]))) { /* * 10.5 (Darwin 9.x), or later. */ new_dlt = find_802_11(&bdl); if (new_dlt != -1) { /* * We have at least one 802.11 DLT_ value, * so this is an 802.11 interface. * new_dlt is the best of the 802.11 * DLT_ values in the list. */ if (p->opt.rfmon) { /* * Our caller wants monitor mode. * Purge DLT_EN10MB from the list * of link-layer types, as selecting * it will keep monitor mode off. */ remove_en(p); /* * If the new mode we want isn't * the default mode, attempt to * select the new mode. */ if (new_dlt != v) { if (ioctl(p->fd, BIOCSDLT, &new_dlt) != -1) { /* * We succeeded; * make this the * new DLT_ value. */ v = new_dlt; } } } else { /* * Our caller doesn't want * monitor mode. Unless this * is being done by pcap_open_live(), * purge the 802.11 link-layer types * from the list, as selecting * one of them will turn monitor * mode on. */ if (!p->oldstyle) remove_802_11(p); } } else { if (p->opt.rfmon) { /* * The caller requested monitor * mode, but we have no 802.11 * link-layer types, so they * can't have it. */ status = PCAP_ERROR_RFMON_NOTSUP; goto bad; } } } } #elif defined(HAVE_BSD_IEEE80211) /* * *BSD with the new 802.11 ioctls. * Do we want monitor mode? */ if (p->opt.rfmon) { /* * Try to put the interface into monitor mode. */ status = monitor_mode(p, 1); if (status != 0) { /* * We failed. */ goto bad; } /* * We're in monitor mode. * Try to find the best 802.11 DLT_ value and, if we * succeed, try to switch to that mode if we're not * already in that mode. */ new_dlt = find_802_11(&bdl); if (new_dlt != -1) { /* * We have at least one 802.11 DLT_ value. * new_dlt is the best of the 802.11 * DLT_ values in the list. * * If the new mode we want isn't the default mode, * attempt to select the new mode. */ if (new_dlt != v) { if (ioctl(p->fd, BIOCSDLT, &new_dlt) != -1) { /* * We succeeded; make this the * new DLT_ value. */ v = new_dlt; } } } } #endif /* various platforms */ #endif /* BIOCGDLTLIST */ /* * If this is an Ethernet device, and we don't have a DLT_ list, * give it a list with DLT_EN10MB and DLT_DOCSIS. (That'd give * 802.11 interfaces DLT_DOCSIS, which isn't the right thing to * do, but there's not much we can do about that without finding * some other way of determining whether it's an Ethernet or 802.11 * device.) */ if (v == DLT_EN10MB && p->dlt_count == 0) { p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2); /* * If that fails, just leave the list empty. */ if (p->dlt_list != NULL) { p->dlt_list[0] = DLT_EN10MB; p->dlt_list[1] = DLT_DOCSIS; p->dlt_count = 2; } } #ifdef PCAP_FDDIPAD if (v == DLT_FDDI) p->fddipad = PCAP_FDDIPAD; else p->fddipad = 0; #endif p->linktype = v; #if defined(BIOCGHDRCMPLT) && defined(BIOCSHDRCMPLT) /* * Do a BIOCSHDRCMPLT, if defined, to turn that flag on, so * the link-layer source address isn't forcibly overwritten. * (Should we ignore errors? Should we do this only if * we're open for writing?) * * XXX - I seem to remember some packet-sending bug in some * BSDs - check CVS log for "bpf.c"? */ if (ioctl(fd, BIOCSHDRCMPLT, &spoof_eth_src) == -1) { (void)snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSHDRCMPLT: %s", pcap_strerror(errno)); status = PCAP_ERROR; goto bad; } #endif /* set timeout */ #ifdef HAVE_ZEROCOPY_BPF if (p->md.timeout != 0 && !p->md.zerocopy) { #else if (p->md.timeout) { #endif /* * XXX - is this seconds/nanoseconds in AIX? * (Treating it as such doesn't fix the timeout * problem described below.) * * XXX - Mac OS X 10.6 mishandles BIOCSRTIMEOUT in * 64-bit userland - it takes, as an argument, a * "struct BPF_TIMEVAL", which has 32-bit tv_sec * and tv_usec, rather than a "struct timeval". * * If this platform defines "struct BPF_TIMEVAL", * we check whether the structure size in BIOCSRTIMEOUT * is that of a "struct timeval" and, if not, we use * a "struct BPF_TIMEVAL" rather than a "struct timeval". * (That way, if the bug is fixed in a future release, * we will still do the right thing.) */ struct timeval to; #ifdef HAVE_STRUCT_BPF_TIMEVAL struct BPF_TIMEVAL bpf_to; if (IOCPARM_LEN(BIOCSRTIMEOUT) != sizeof(struct timeval)) { bpf_to.tv_sec = p->md.timeout / 1000; bpf_to.tv_usec = (p->md.timeout * 1000) % 1000000; if (ioctl(p->fd, BIOCSRTIMEOUT, (caddr_t)&bpf_to) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSRTIMEOUT: %s", pcap_strerror(errno)); status = PCAP_ERROR; goto bad; } } else { #endif to.tv_sec = p->md.timeout / 1000; to.tv_usec = (p->md.timeout * 1000) % 1000000; if (ioctl(p->fd, BIOCSRTIMEOUT, (caddr_t)&to) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSRTIMEOUT: %s", pcap_strerror(errno)); status = PCAP_ERROR; goto bad; } #ifdef HAVE_STRUCT_BPF_TIMEVAL } #endif } #ifdef _AIX #ifdef BIOCIMMEDIATE /* * Darren Reed notes that * * On AIX (4.2 at least), if BIOCIMMEDIATE is not set, the * timeout appears to be ignored and it waits until the buffer * is filled before returning. The result of not having it * set is almost worse than useless if your BPF filter * is reducing things to only a few packets (i.e. one every * second or so). * * so we turn BIOCIMMEDIATE mode on if this is AIX. * * We don't turn it on for other platforms, as that means we * get woken up for every packet, which may not be what we want; * in the Winter 1993 USENIX paper on BPF, they say: * * Since a process might want to look at every packet on a * network and the time between packets can be only a few * microseconds, it is not possible to do a read system call * per packet and BPF must collect the data from several * packets and return it as a unit when the monitoring * application does a read. * * which I infer is the reason for the timeout - it means we * wait that amount of time, in the hopes that more packets * will arrive and we'll get them all with one read. * * Setting BIOCIMMEDIATE mode on FreeBSD (and probably other * BSDs) causes the timeout to be ignored. * * On the other hand, some platforms (e.g., Linux) don't support * timeouts, they just hand stuff to you as soon as it arrives; * if that doesn't cause a problem on those platforms, it may * be OK to have BIOCIMMEDIATE mode on BSD as well. * * (Note, though, that applications may depend on the read * completing, even if no packets have arrived, when the timeout * expires, e.g. GUI applications that have to check for input * while waiting for packets to arrive; a non-zero timeout * prevents "select()" from working right on FreeBSD and * possibly other BSDs, as the timer doesn't start until a * "read()" is done, so the timer isn't in effect if the * application is blocked on a "select()", and the "select()" * doesn't get woken up for a BPF device until the buffer * fills up.) */ v = 1; if (ioctl(p->fd, BIOCIMMEDIATE, &v) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCIMMEDIATE: %s", pcap_strerror(errno)); status = PCAP_ERROR; goto bad; } #endif /* BIOCIMMEDIATE */ #endif /* _AIX */ if (p->opt.promisc) { /* set promiscuous mode, just warn if it fails */ if (ioctl(p->fd, BIOCPROMISC, NULL) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCPROMISC: %s", pcap_strerror(errno)); status = PCAP_WARNING_PROMISC_NOTSUP; } } if (ioctl(fd, BIOCGBLEN, (caddr_t)&v) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCGBLEN: %s", pcap_strerror(errno)); status = PCAP_ERROR; goto bad; } p->bufsize = v; #ifdef HAVE_ZEROCOPY_BPF if (!p->md.zerocopy) { #endif p->buffer = (u_char *)malloc(p->bufsize); if (p->buffer == NULL) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); status = PCAP_ERROR; goto bad; } #ifdef _AIX /* For some strange reason this seems to prevent the EFAULT * problems we have experienced from AIX BPF. */ memset(p->buffer, 0x0, p->bufsize); #endif #ifdef HAVE_ZEROCOPY_BPF } #endif /* * If there's no filter program installed, there's * no indication to the kernel of what the snapshot * length should be, so no snapshotting is done. * * Therefore, when we open the device, we install * an "accept everything" filter with the specified * snapshot length. */ total_insn.code = (u_short)(BPF_RET | BPF_K); total_insn.jt = 0; total_insn.jf = 0; total_insn.k = p->snapshot; total_prog.bf_len = 1; total_prog.bf_insns = &total_insn; if (ioctl(p->fd, BIOCSETF, (caddr_t)&total_prog) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETF: %s", pcap_strerror(errno)); status = PCAP_ERROR; goto bad; } /* * On most BPF platforms, either you can do a "select()" or * "poll()" on a BPF file descriptor and it works correctly, * or you can do it and it will return "readable" if the * hold buffer is full but not if the timeout expires *and* * a non-blocking read will, if the hold buffer is empty * but the store buffer isn't empty, rotate the buffers * and return what packets are available. * * In the latter case, the fact that a non-blocking read * will give you the available packets means you can work * around the failure of "select()" and "poll()" to wake up * and return "readable" when the timeout expires by using * the timeout as the "select()" or "poll()" timeout, putting * the BPF descriptor into non-blocking mode, and read from * it regardless of whether "select()" reports it as readable * or not. * * However, in FreeBSD 4.3 and 4.4, "select()" and "poll()" * won't wake up and return "readable" if the timer expires * and non-blocking reads return EWOULDBLOCK if the hold * buffer is empty, even if the store buffer is non-empty. * * This means the workaround in question won't work. * * Therefore, on FreeBSD 4.3 and 4.4, we set "p->selectable_fd" * to -1, which means "sorry, you can't use 'select()' or 'poll()' * here". On all other BPF platforms, we set it to the FD for * the BPF device; in NetBSD, OpenBSD, and Darwin, a non-blocking * read will, if the hold buffer is empty and the store buffer * isn't empty, rotate the buffers and return what packets are * there (and in sufficiently recent versions of OpenBSD * "select()" and "poll()" should work correctly). * * XXX - what about AIX? */ p->selectable_fd = p->fd; /* assume select() works until we know otherwise */ if (have_osinfo) { /* * We can check what OS this is. */ if (strcmp(osinfo.sysname, "FreeBSD") == 0) { if (strncmp(osinfo.release, "4.3-", 4) == 0 || strncmp(osinfo.release, "4.4-", 4) == 0) p->selectable_fd = -1; } } p->read_op = pcap_read_bpf; p->inject_op = pcap_inject_bpf; p->setfilter_op = pcap_setfilter_bpf; p->setdirection_op = pcap_setdirection_bpf; p->set_datalink_op = pcap_set_datalink_bpf; p->getnonblock_op = pcap_getnonblock_bpf; p->setnonblock_op = pcap_setnonblock_bpf; p->stats_op = pcap_stats_bpf; p->cleanup_op = pcap_cleanup_bpf; return (status); bad: pcap_cleanup_bpf(p); return (status); } int pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf) { #ifdef HAVE_DAG_API if (dag_platform_finddevs(alldevsp, errbuf) < 0) return (-1); #endif /* HAVE_DAG_API */ #ifdef HAVE_SNF_API if (snf_platform_finddevs(alldevsp, errbuf) < 0) return (-1); #endif /* HAVE_SNF_API */ return (0); } #ifdef HAVE_BSD_IEEE80211 static int monitor_mode(pcap_t *p, int set) { int sock; struct ifmediareq req; int *media_list; int i; int can_do; struct ifreq ifr; sock = socket(AF_INET, SOCK_DGRAM, 0); if (sock == -1) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "can't open socket: %s", pcap_strerror(errno)); return (PCAP_ERROR); } memset(&req, 0, sizeof req); strncpy(req.ifm_name, p->opt.source, sizeof req.ifm_name); /* * Find out how many media types we have. */ if (ioctl(sock, SIOCGIFMEDIA, &req) < 0) { /* * Can't get the media types. */ switch (errno) { case ENXIO: /* * There's no such device. */ close(sock); return (PCAP_ERROR_NO_SUCH_DEVICE); case EINVAL: /* * Interface doesn't support SIOC{G,S}IFMEDIA. */ close(sock); return (PCAP_ERROR_RFMON_NOTSUP); default: snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFMEDIA 1: %s", pcap_strerror(errno)); close(sock); return (PCAP_ERROR); } } if (req.ifm_count == 0) { /* * No media types. */ close(sock); return (PCAP_ERROR_RFMON_NOTSUP); } /* * Allocate a buffer to hold all the media types, and * get the media types. */ media_list = malloc(req.ifm_count * sizeof(int)); if (media_list == NULL) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); close(sock); return (PCAP_ERROR); } req.ifm_ulist = media_list; if (ioctl(sock, SIOCGIFMEDIA, &req) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFMEDIA: %s", pcap_strerror(errno)); free(media_list); close(sock); return (PCAP_ERROR); } /* * Look for an 802.11 "automatic" media type. * We assume that all 802.11 adapters have that media type, * and that it will carry the monitor mode supported flag. */ can_do = 0; for (i = 0; i < req.ifm_count; i++) { if (IFM_TYPE(media_list[i]) == IFM_IEEE80211 && IFM_SUBTYPE(media_list[i]) == IFM_AUTO) { /* OK, does it do monitor mode? */ if (media_list[i] & IFM_IEEE80211_MONITOR) { can_do = 1; break; } } } free(media_list); if (!can_do) { /* * This adapter doesn't support monitor mode. */ close(sock); return (PCAP_ERROR_RFMON_NOTSUP); } if (set) { /* * Don't just check whether we can enable monitor mode, * do so, if it's not already enabled. */ if ((req.ifm_current & IFM_IEEE80211_MONITOR) == 0) { /* * Monitor 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(p)) { /* * "atexit()" failed; don't put the interface * in monitor mode, just give up. */ snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "atexit failed"); close(sock); return (PCAP_ERROR); } memset(&ifr, 0, sizeof(ifr)); (void)strncpy(ifr.ifr_name, p->opt.source, sizeof(ifr.ifr_name)); ifr.ifr_media = req.ifm_current | IFM_IEEE80211_MONITOR; if (ioctl(sock, SIOCSIFMEDIA, &ifr) == -1) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCSIFMEDIA: %s", pcap_strerror(errno)); close(sock); return (PCAP_ERROR); } p->md.must_do_on_close |= MUST_CLEAR_RFMON; /* * Add this to the list of pcaps to close when we exit. */ pcap_add_to_pcaps_to_close(p); } } return (0); } #endif /* HAVE_BSD_IEEE80211 */ #if defined(BIOCGDLTLIST) && (defined(__APPLE__) || defined(HAVE_BSD_IEEE80211)) /* * Check whether we have any 802.11 link-layer types; return the best * of the 802.11 link-layer types if we find one, and return -1 * otherwise. * * DLT_IEEE802_11_RADIO, with the radiotap header, is considered the * best 802.11 link-layer type; any of the other 802.11-plus-radio * headers are second-best; 802.11 with no radio information is * the least good. */ static int find_802_11(struct bpf_dltlist *bdlp) { int new_dlt; int i; /* * Scan the list of DLT_ values, looking for 802.11 values, * and, if we find any, choose the best of them. */ new_dlt = -1; for (i = 0; i < bdlp->bfl_len; i++) { switch (bdlp->bfl_list[i]) { case DLT_IEEE802_11: /* * 802.11, but no radio. * * Offer this, and select it as the new mode * unless we've already found an 802.11 * header with radio information. */ if (new_dlt == -1) new_dlt = bdlp->bfl_list[i]; break; case DLT_PRISM_HEADER: case DLT_AIRONET_HEADER: case DLT_IEEE802_11_RADIO_AVS: /* * 802.11 with radio, but not radiotap. * * Offer this, and select it as the new mode * unless we've already found the radiotap DLT_. */ if (new_dlt != DLT_IEEE802_11_RADIO) new_dlt = bdlp->bfl_list[i]; break; case DLT_IEEE802_11_RADIO: /* * 802.11 with radiotap. * * Offer this, and select it as the new mode. */ new_dlt = bdlp->bfl_list[i]; break; default: /* * Not 802.11. */ break; } } return (new_dlt); } #endif /* defined(BIOCGDLTLIST) && (defined(__APPLE__) || defined(HAVE_BSD_IEEE80211)) */ #if defined(__APPLE__) && defined(BIOCGDLTLIST) /* * Remove DLT_EN10MB from the list of DLT_ values, as we're in monitor mode, * and DLT_EN10MB isn't supported in monitor mode. */ static void remove_en(pcap_t *p) { int i, j; /* * Scan the list of DLT_ values and discard DLT_EN10MB. */ j = 0; for (i = 0; i < p->dlt_count; i++) { switch (p->dlt_list[i]) { case DLT_EN10MB: /* * Don't offer this one. */ continue; default: /* * Just copy this mode over. */ break; } /* * Copy this DLT_ value to its new position. */ p->dlt_list[j] = p->dlt_list[i]; j++; } /* * Set the DLT_ count to the number of entries we copied. */ p->dlt_count = j; } /* * Remove 802.11 link-layer types from the list of DLT_ values, as * we're not in monitor mode, and those DLT_ values will switch us * to monitor mode. */ static void remove_802_11(pcap_t *p) { int i, j; /* * Scan the list of DLT_ values and discard 802.11 values. */ j = 0; for (i = 0; i < p->dlt_count; i++) { switch (p->dlt_list[i]) { case DLT_IEEE802_11: case DLT_PRISM_HEADER: case DLT_AIRONET_HEADER: case DLT_IEEE802_11_RADIO: case DLT_IEEE802_11_RADIO_AVS: /* * 802.11. Don't offer this one. */ continue; default: /* * Just copy this mode over. */ break; } /* * Copy this DLT_ value to its new position. */ p->dlt_list[j] = p->dlt_list[i]; j++; } /* * Set the DLT_ count to the number of entries we copied. */ p->dlt_count = j; } #endif /* defined(__APPLE__) && defined(BIOCGDLTLIST) */ static int pcap_setfilter_bpf(pcap_t *p, struct bpf_program *fp) { /* * Free any user-mode filter we might happen to have installed. */ pcap_freecode(&p->fcode); /* * Try to install the kernel filter. */ if (ioctl(p->fd, BIOCSETF, (caddr_t)fp) == 0) { /* * It worked. */ p->md.use_bpf = 1; /* filtering in the kernel */ /* * Discard any previously-received packets, as they might * have passed whatever filter was formerly in effect, but * might not pass this filter (BIOCSETF discards packets * buffered in the kernel, so you can lose packets in any * case). */ p->cc = 0; return (0); } /* * We failed. * * If it failed with EINVAL, that's probably because the program * is invalid or too big. Validate it ourselves; if we like it * (we currently allow backward branches, to support protochain), * run it in userland. (There's no notion of "too big" for * userland.) * * Otherwise, just give up. * XXX - if the copy of the program into the kernel failed, * we will get EINVAL rather than, say, EFAULT on at least * some kernels. */ if (errno != EINVAL) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETF: %s", pcap_strerror(errno)); return (-1); } /* * install_bpf_program() validates the program. * * XXX - what if we already have a filter in the kernel? */ if (install_bpf_program(p, fp) < 0) return (-1); p->md.use_bpf = 0; /* filtering in userland */ return (0); } /* * Set direction flag: Which packets do we accept on a forwarding * single device? IN, OUT or both? */ static int pcap_setdirection_bpf(pcap_t *p, pcap_direction_t d) { #if defined(BIOCSDIRECTION) u_int direction; direction = (d == PCAP_D_IN) ? BPF_D_IN : ((d == PCAP_D_OUT) ? BPF_D_OUT : BPF_D_INOUT); if (ioctl(p->fd, BIOCSDIRECTION, &direction) == -1) { (void) snprintf(p->errbuf, sizeof(p->errbuf), "Cannot set direction to %s: %s", (d == PCAP_D_IN) ? "PCAP_D_IN" : ((d == PCAP_D_OUT) ? "PCAP_D_OUT" : "PCAP_D_INOUT"), strerror(errno)); return (-1); } return (0); #elif defined(BIOCSSEESENT) u_int seesent; /* * We don't support PCAP_D_OUT. */ if (d == PCAP_D_OUT) { snprintf(p->errbuf, sizeof(p->errbuf), "Setting direction to PCAP_D_OUT is not supported on BPF"); return -1; } seesent = (d == PCAP_D_INOUT); if (ioctl(p->fd, BIOCSSEESENT, &seesent) == -1) { (void) snprintf(p->errbuf, sizeof(p->errbuf), "Cannot set direction to %s: %s", (d == PCAP_D_INOUT) ? "PCAP_D_INOUT" : "PCAP_D_IN", strerror(errno)); return (-1); } return (0); #else (void) snprintf(p->errbuf, sizeof(p->errbuf), "This system doesn't support BIOCSSEESENT, so the direction can't be set"); return (-1); #endif } static int pcap_set_datalink_bpf(pcap_t *p, int dlt) { #ifdef BIOCSDLT if (ioctl(p->fd, BIOCSDLT, &dlt) == -1) { (void) snprintf(p->errbuf, sizeof(p->errbuf), "Cannot set DLT %d: %s", dlt, strerror(errno)); return (-1); } #endif return (0); }