/* * Copyright (c) 1993, 1994, 1995, 1996, 1997 * 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-snoop.c,v 1.55.2.3 2008-04-14 20:41:52 guy Exp $ (LBL)"; #endif #ifdef HAVE_CONFIG_H #include "config.h" #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "pcap-int.h" #ifdef HAVE_OS_PROTO_H #include "os-proto.h" #endif static int pcap_read_snoop(pcap_t *p, int cnt, pcap_handler callback, u_char *user) { int cc; register struct snoopheader *sh; register u_int datalen; register u_int caplen; register u_char *cp; again: /* * Has "pcap_breakloop()" been called? */ if (p->break_loop) { /* * Yes - clear the flag that indicates that it * has, and return -2 to indicate that we were * told to break out of the loop. */ p->break_loop = 0; return (-2); } 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; case EWOULDBLOCK: return (0); /* XXX */ } snprintf(p->errbuf, sizeof(p->errbuf), "read: %s", pcap_strerror(errno)); return (-1); } sh = (struct snoopheader *)p->buffer; datalen = sh->snoop_packetlen; /* * XXX - Sigh, snoop_packetlen is a 16 bit quantity. If we * got a short length, but read a full sized snoop pakcet, * assume we overflowed and add back the 64K... */ if (cc == (p->snapshot + sizeof(struct snoopheader)) && (datalen < p->snapshot)) datalen += (64 * 1024); caplen = (datalen < p->snapshot) ? datalen : p->snapshot; cp = (u_char *)(sh + 1) + p->offset; /* XXX */ /* * XXX unfortunately snoop loopback isn't exactly like * BSD's. The address family is encoded in the first 2 * bytes rather than the first 4 bytes! Luckily the last * two snoop loopback bytes are zeroed. */ if (p->linktype == DLT_NULL && *((short *)(cp + 2)) == 0) { u_int *uip = (u_int *)cp; *uip >>= 16; } if (p->fcode.bf_insns == NULL || bpf_filter(p->fcode.bf_insns, cp, datalen, caplen)) { struct pcap_pkthdr h; ++p->md.stat.ps_recv; h.ts.tv_sec = sh->snoop_timestamp.tv_sec; h.ts.tv_usec = sh->snoop_timestamp.tv_usec; h.len = datalen; h.caplen = caplen; (*callback)(user, &h, cp); return (1); } return (0); } static int pcap_inject_snoop(pcap_t *p, const void *buf, size_t size) { int ret; /* * XXX - libnet overwrites the source address with what I * presume is the interface's address; is that required? */ ret = write(p->fd, buf, size); if (ret == -1) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s", pcap_strerror(errno)); return (-1); } return (ret); } static int pcap_stats_snoop(pcap_t *p, struct pcap_stat *ps) { register struct rawstats *rs; struct rawstats rawstats; rs = &rawstats; memset(rs, 0, sizeof(*rs)); if (ioctl(p->fd, SIOCRAWSTATS, (char *)rs) < 0) { snprintf(p->errbuf, sizeof(p->errbuf), "SIOCRAWSTATS: %s", pcap_strerror(errno)); return (-1); } /* * "ifdrops" are those dropped by the network interface * due to resource shortages or hardware errors. * * "sbdrops" are those dropped due to socket buffer limits. * * As filter is done in userland, "sbdrops" counts packets * regardless of whether they would've passed the filter. * * XXX - does this count *all* Snoop or Drain sockets, * rather than just this socket? If not, why does it have * both Snoop and Drain statistics? */ p->md.stat.ps_drop = rs->rs_snoop.ss_ifdrops + rs->rs_snoop.ss_sbdrops + rs->rs_drain.ds_ifdrops + rs->rs_drain.ds_sbdrops; /* * "ps_recv" counts only packets that passed the filter. * As filtering is done in userland, this does not include * packets dropped because we ran out of buffer space. */ *ps = p->md.stat; return (0); } /* XXX can't disable promiscuous */ static int pcap_activate_snoop(pcap_t *p) { int fd; struct sockaddr_raw sr; struct snoopfilter sf; u_int v; int ll_hdrlen; int snooplen; struct ifreq ifr; fd = socket(PF_RAW, SOCK_RAW, RAWPROTO_SNOOP); if (fd < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "snoop socket: %s", pcap_strerror(errno)); goto bad; } p->fd = fd; memset(&sr, 0, sizeof(sr)); sr.sr_family = AF_RAW; (void)strncpy(sr.sr_ifname, p->opt.source, sizeof(sr.sr_ifname)); if (bind(fd, (struct sockaddr *)&sr, sizeof(sr))) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "snoop bind: %s", pcap_strerror(errno)); goto bad; } memset(&sf, 0, sizeof(sf)); if (ioctl(fd, SIOCADDSNOOP, &sf) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCADDSNOOP: %s", pcap_strerror(errno)); goto bad; } if (handle->opt.buffer_size != 0) v = handle->opt.buffer_size; else v = 64 * 1024; /* default to 64K buffer size */ (void)setsockopt(fd, SOL_SOCKET, SO_RCVBUF, (char *)&v, sizeof(v)); /* * XXX hack - map device name to link layer type */ if (strncmp("et", p->opt.source, 2) == 0 || /* Challenge 10 Mbit */ strncmp("ec", p->opt.source, 2) == 0 || /* Indigo/Indy 10 Mbit, O2 10/100 */ strncmp("ef", p->opt.source, 2) == 0 || /* O200/2000 10/100 Mbit */ strncmp("eg", p->opt.source, 2) == 0 || /* Octane/O2xxx/O3xxx Gigabit */ strncmp("gfe", p->opt.source, 3) == 0 || /* GIO 100 Mbit */ strncmp("fxp", p->opt.source, 3) == 0 || /* Challenge VME Enet */ strncmp("ep", p->opt.source, 2) == 0 || /* Challenge 8x10 Mbit EPLEX */ strncmp("vfe", p->opt.source, 3) == 0 || /* Challenge VME 100Mbit */ strncmp("fa", p->opt.source, 2) == 0 || strncmp("qaa", p->opt.source, 3) == 0 || strncmp("cip", p->opt.source, 3) == 0 || strncmp("el", p->opt.source, 2) == 0) { p->linktype = DLT_EN10MB; p->offset = RAW_HDRPAD(sizeof(struct ether_header)); ll_hdrlen = sizeof(struct ether_header); /* * This is (presumably) a real Ethernet capture; give it a * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, 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). * * XXX - are there any sorts of "fake Ethernet" that have * Ethernet link-layer headers but that *shouldn't offer * DLT_DOCSIS as a Cisco CMTS won't put traffic onto it * or get traffic bridged onto it? "el" is for ATM LANE * Ethernet devices, so that might be the case for them; * the same applies for "qaa" classical IP devices. If * "fa" devices are for FORE SPANS, that'd apply to them * as well; what are "cip" devices - some other ATM * Classical IP devices? */ 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; } } else if (strncmp("ipg", p->opt.source, 3) == 0 || strncmp("rns", p->opt.source, 3) == 0 || /* O2/200/2000 FDDI */ strncmp("xpi", p->opt.source, 3) == 0) { p->linktype = DLT_FDDI; p->offset = 3; /* XXX yeah? */ ll_hdrlen = 13; } else if (strncmp("ppp", p->opt.source, 3) == 0) { p->linktype = DLT_RAW; ll_hdrlen = 0; /* DLT_RAW meaning "no PPP header, just the IP packet"? */ } else if (strncmp("qfa", p->opt.source, 3) == 0) { p->linktype = DLT_IP_OVER_FC; ll_hdrlen = 24; } else if (strncmp("pl", p->opt.source, 2) == 0) { p->linktype = DLT_RAW; ll_hdrlen = 0; /* Cray UNICOS/mp pseudo link */ } else if (strncmp("lo", p->opt.source, 2) == 0) { p->linktype = DLT_NULL; ll_hdrlen = 4; } else { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "snoop: unknown physical layer type"); goto bad; } if (p->opt.rfmon) { /* * No monitor mode on Irix (no Wi-Fi devices on * hardware supported by Irix). */ return (PCAP_ERROR_RFMON_NOTSUP); } #ifdef SIOCGIFMTU /* * XXX - IRIX appears to give you an error if you try to set the * capture length to be greater than the MTU, so let's try to get * the MTU first and, if that succeeds, trim the snap length * to be no greater than the MTU. */ (void)strncpy(ifr.ifr_name, p->opt.source, sizeof(ifr.ifr_name)); if (ioctl(fd, SIOCGIFMTU, (char *)&ifr) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFMTU: %s", pcap_strerror(errno)); goto bad; } /* * OK, we got it. * * XXX - some versions of IRIX 6.5 define "ifr_mtu" and have an * "ifru_metric" member of the "ifr_ifru" union in an "ifreq" * structure, others don't. * * I've no idea what's going on, so, if "ifr_mtu" isn't defined, * we define it as "ifr_metric", as using that field appears to * work on the versions that lack "ifr_mtu" (and, on those that * don't lack it, "ifru_metric" and "ifru_mtu" are both "int" * members of the "ifr_ifru" union, which suggests that they * may be interchangeable in this case). */ #ifndef ifr_mtu #define ifr_mtu ifr_metric #endif if (p->snapshot > ifr.ifr_mtu + ll_hdrlen) p->snapshot = ifr.ifr_mtu + ll_hdrlen; #endif /* * The argument to SIOCSNOOPLEN is the number of link-layer * payload bytes to capture - it doesn't count link-layer * header bytes. */ snooplen = p->snapshot - ll_hdrlen; if (snooplen < 0) snooplen = 0; if (ioctl(fd, SIOCSNOOPLEN, &snooplen) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCSNOOPLEN: %s", pcap_strerror(errno)); goto bad; } v = 1; if (ioctl(fd, SIOCSNOOPING, &v) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCSNOOPING: %s", pcap_strerror(errno)); goto bad; } p->bufsize = 4096; /* XXX */ p->buffer = (u_char *)malloc(p->bufsize); if (p->buffer == NULL) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); goto bad; } /* * "p->fd" is a socket, so "select()" should work on it. */ p->selectable_fd = p->fd; p->read_op = pcap_read_snoop; p->inject_op = pcap_inject_snoop; p->setfilter_op = install_bpf_program; /* no kernel filtering */ p->setdirection_op = NULL; /* Not implemented. */ p->set_datalink_op = NULL; /* can't change data link type */ p->getnonblock_op = pcap_getnonblock_fd; p->setnonblock_op = pcap_setnonblock_fd; p->stats_op = pcap_stats_snoop; return (0); bad: return (PCAP_ERROR); } pcap_t * pcap_create(const char *device, char *ebuf) { pcap_t *p; p = pcap_create_common(device, ebuf); if (p == NULL) return (NULL); p->activate_op = pcap_activate_snoop; return (p); } int pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf) { return (0); }