For Linux non-mmapped captures, Linux bluetooth captures, and Irix

[libpcap] / pcap-snoop.c

/*
 * 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 1.57 2008-04-07 03:57:32 guy Exp $ (LBL)";
#endif

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <sys/param.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/time.h>

#include <net/raw.h>
#include <net/if.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/if_ether.h>
#include <netinet/ip_var.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#include <netinet/tcp.h>
#include <netinet/tcpip.h>

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#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;

        if (p->opt.rfmon) {
                /*
                 * No monitor mode on Irix (no Wi-Fi devices on
                 * hardware supported by Irix).
                 */
                return (PCAP_ERROR_RFMON_NOTSUP);
        }

        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;
        }
#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;
        p->close_op = pcap_close_common;

        return (0);
 bad:
        (void)close(fd);
        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);
}