text: /*
   * 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 <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;
  
  	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);
  }
  