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/*
* 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 1.54.2.1 2005/05/03 18:54:38 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 */
pcap_t *
pcap_open_live(const char *device, int snaplen, int promisc, int to_ms,
char *ebuf)
{
int fd;
struct sockaddr_raw sr;
struct snoopfilter sf;
u_int v;
int ll_hdrlen;
int snooplen;
pcap_t *p;
struct ifreq ifr;
p = (pcap_t *)malloc(sizeof(*p));
if (p == NULL) {
snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
pcap_strerror(errno));
return (NULL);
}
memset(p, 0, sizeof(*p));
fd = socket(PF_RAW, SOCK_RAW, RAWPROTO_SNOOP);
if (fd < 0) {
snprintf(ebuf, 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, device, sizeof(sr.sr_ifname));
if (bind(fd, (struct sockaddr *)&sr, sizeof(sr))) {
snprintf(ebuf, PCAP_ERRBUF_SIZE, "snoop bind: %s",
pcap_strerror(errno));
goto bad;
}
memset(&sf, 0, sizeof(sf));
if (ioctl(fd, SIOCADDSNOOP, &sf) < 0) {
snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCADDSNOOP: %s",
pcap_strerror(errno));
goto bad;
}
v = 64 * 1024;
(void)setsockopt(fd, SOL_SOCKET, SO_RCVBUF, (char *)&v, sizeof(v));
/*
* XXX hack - map device name to link layer type
*/
if (strncmp("et", device, 2) == 0 || /* Challenge 10 Mbit */
strncmp("ec", device, 2) == 0 || /* Indigo/Indy 10 Mbit,
O2 10/100 */
strncmp("ef", device, 2) == 0 || /* O200/2000 10/100 Mbit */
strncmp("eg", device, 2) == 0 || /* Octane/O2xxx/O3xxx Gigabit */
strncmp("gfe", device, 3) == 0 || /* GIO 100 Mbit */
strncmp("fxp", device, 3) == 0 || /* Challenge VME Enet */
strncmp("ep", device, 2) == 0 || /* Challenge 8x10 Mbit EPLEX */
strncmp("vfe", device, 3) == 0 || /* Challenge VME 100Mbit */
strncmp("fa", device, 2) == 0 ||
strncmp("qaa", device, 3) == 0 ||
strncmp("cip", device, 3) == 0 ||
strncmp("el", device, 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", device, 3) == 0 ||
strncmp("rns", device, 3) == 0 || /* O2/200/2000 FDDI */
strncmp("xpi", device, 3) == 0) {
p->linktype = DLT_FDDI;
p->offset = 3; /* XXX yeah? */
ll_hdrlen = 13;
} else if (strncmp("ppp", device, 3) == 0) {
p->linktype = DLT_RAW;
ll_hdrlen = 0; /* DLT_RAW meaning "no PPP header, just the IP packet"? */
} else if (strncmp("qfa", device, 3) == 0) {
p->linktype = DLT_IP_OVER_FC;
ll_hdrlen = 24;
} else if (strncmp("pl", device, 2) == 0) {
p->linktype = DLT_RAW;
ll_hdrlen = 0; /* Cray UNICOS/mp pseudo link */
} else if (strncmp("lo", device, 2) == 0) {
p->linktype = DLT_NULL;
ll_hdrlen = 4;
} else {
snprintf(ebuf, 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, device, sizeof(ifr.ifr_name));
if (ioctl(fd, SIOCGIFMTU, (char *)&ifr) < 0) {
snprintf(ebuf, 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 (snaplen > ifr.ifr_mtu + ll_hdrlen)
snaplen = 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 = snaplen - ll_hdrlen;
if (snooplen < 0)
snooplen = 0;
if (ioctl(fd, SIOCSNOOPLEN, &snooplen) < 0) {
snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCSNOOPLEN: %s",
pcap_strerror(errno));
goto bad;
}
p->snapshot = snaplen;
v = 1;
if (ioctl(fd, SIOCSNOOPING, &v) < 0) {
snprintf(ebuf, 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(ebuf, 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 (p);
bad:
(void)close(fd);
/*
* Get rid of any link-layer type list we allocated.
*/
if (p->dlt_list != NULL)
free(p->dlt_list);
free(p);
return (NULL);
}
int
pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
{
return (0);
}
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