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print-ether.c

/*
 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000
 *    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/tcpdump/print-ether.c,v 1.82.2.3 2003/12/29 22:42:21 hannes Exp $ (LBL)";
#endif

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

#include <tcpdump-stdinc.h>

#include <stdio.h>
#include <pcap.h>

#include "interface.h"
#include "addrtoname.h"
#include "ethertype.h"

#include "ether.h"

const u_char *snapend;

const struct tok ethertype_values[] = { 
    { ETHERTYPE_IP,           "IPv4" },
    { ETHERTYPE_MPLS,         "MPLS unicast" },
    { ETHERTYPE_MPLS_MULTI,   "MPLS multicast" },
    { ETHERTYPE_IPV6,         "IPv6" },
    { ETHERTYPE_8021Q,        "802.1Q" },
    { ETHERTYPE_VMAN,         "VMAN" },
    { ETHERTYPE_PUP,            "PUP" },
    { ETHERTYPE_ARP,            "ARP"},
    { ETHERTYPE_REVARP ,        "Reverse ARP"},
    { ETHERTYPE_NS,             "NS" },
    { ETHERTYPE_SPRITE,         "Sprite" },
    { ETHERTYPE_TRAIL,          "Trail" },
    { ETHERTYPE_MOPDL,          "MOP DL" },
    { ETHERTYPE_MOPRC,          "MOP RC" },
    { ETHERTYPE_DN,             "DN" },
    { ETHERTYPE_LAT,            "LAT" },
    { ETHERTYPE_SCA,            "SCA" },
    { ETHERTYPE_LANBRIDGE,      "Lanbridge" },
    { ETHERTYPE_DECDNS,         "DEC DNS" },
    { ETHERTYPE_DECDTS,         "DEC DTS" },
    { ETHERTYPE_VEXP,           "VEXP" },
    { ETHERTYPE_VPROD,          "VPROD" },
    { ETHERTYPE_ATALK,          "Appletalk" },
    { ETHERTYPE_AARP,           "Appletalk ARP" },
    { ETHERTYPE_IPX,            "IPX" },
    { ETHERTYPE_PPP,            "PPP" },
    { ETHERTYPE_PPPOED,         "PPPoE D" },
    { ETHERTYPE_PPPOES,         "PPPoE S" },
    { ETHERTYPE_LOOPBACK,       "Loopback" },
    { 0, NULL}
};

static inline void
ether_hdr_print(register const u_char *bp, u_int length)
{
      register const struct ether_header *ep;
      ep = (const struct ether_header *)bp;

      (void)printf("%s > %s",
                 etheraddr_string(ESRC(ep)),
                 etheraddr_string(EDST(ep)));

      if (!qflag) {
              if (ntohs(ep->ether_type) <= ETHERMTU)
                      (void)printf(", 802.3");
                else 
                      (void)printf(", ethertype %s (0x%04x)",
                               tok2str(ethertype_values,"Unknown", ntohs(ep->ether_type)),
                                       ntohs(ep->ether_type));          
        } else {
                if (ntohs(ep->ether_type) <= ETHERMTU)
                          (void)printf(", 802.3");
                else 
                          (void)printf(", %s", tok2str(ethertype_values,"Unknown Ethertype (0x%04x)", ntohs(ep->ether_type)));  
        }

      (void)printf(", length %u: ", length);
}

void
ether_print(const u_char *p, u_int length, u_int caplen)
{
      struct ether_header *ep;
      u_short ether_type;
      u_short extracted_ether_type;

      if (caplen < ETHER_HDRLEN) {
            printf("[|ether]");
            return;
      }

      if (eflag)
            ether_hdr_print(p, length);

      length -= ETHER_HDRLEN;
      caplen -= ETHER_HDRLEN;
      ep = (struct ether_header *)p;
      p += ETHER_HDRLEN;

      ether_type = ntohs(ep->ether_type);

      /*
       * Is it (gag) an 802.3 encapsulation?
       */
      extracted_ether_type = 0;
      if (ether_type <= ETHERMTU) {
            /* Try to print the LLC-layer header & higher layers */
            if (llc_print(p, length, caplen, ESRC(ep), EDST(ep),
                &extracted_ether_type) == 0) {
                  /* ether_type not known, print raw packet */
                  if (!eflag)
                        ether_hdr_print((u_char *)ep, length + ETHER_HDRLEN);

                  if (!xflag && !qflag)
                        default_print(p, caplen);
            }
      } else if (ether_encap_print(ether_type, p, length, caplen,
          &extracted_ether_type) == 0) {
            /* ether_type not known, print raw packet */
            if (!eflag)
                  ether_hdr_print((u_char *)ep, length + ETHER_HDRLEN);

            if (!xflag && !qflag)
                  default_print(p, caplen);
      } 
}

/*
 * This is the top level routine of the printer.  'p' points
 * to the ether header of the packet, 'h->ts' is the timestamp,
 * 'h->length' is the length of the packet off the wire, and 'h->caplen'
 * is the number of bytes actually captured.
 */
u_int
ether_if_print(const struct pcap_pkthdr *h, const u_char *p)
{
      ether_print(p, h->len, h->caplen);

      return (ETHER_HDRLEN);
}

/*
 * Prints the packet encapsulated in an Ethernet data segment
 * (or an equivalent encapsulation), given the Ethernet type code.
 *
 * Returns non-zero if it can do so, zero if the ethertype is unknown.
 *
 * The Ethernet type code is passed through a pointer; if it was
 * ETHERTYPE_8021Q, it gets updated to be the Ethernet type of
 * the 802.1Q payload, for the benefit of lower layers that might
 * want to know what it is.
 */

int
ether_encap_print(u_short ether_type, const u_char *p,
    u_int length, u_int caplen, u_short *extracted_ether_type)
{
 recurse:
      *extracted_ether_type = ether_type;

      switch (ether_type) {

      case ETHERTYPE_IP:
            ip_print(p, length);
            return (1);

#ifdef INET6
      case ETHERTYPE_IPV6:
            ip6_print(p, length);
            return (1);
#endif /*INET6*/

      case ETHERTYPE_ARP:
      case ETHERTYPE_REVARP:
            arp_print(p, length, caplen);
            return (1);

      case ETHERTYPE_DN:
            decnet_print(p, length, caplen);
            return (1);

      case ETHERTYPE_ATALK:
            if (vflag)
                  fputs("et1 ", stdout);
            atalk_print(p, length);
            return (1);

      case ETHERTYPE_AARP:
            aarp_print(p, length);
            return (1);

      case ETHERTYPE_IPX:
            printf("(NOV-ETHII) ");
            ipx_print(p, length);
            return (1);

      case ETHERTYPE_8021Q:
              if (eflag)
                printf("vlan %u, p %u%s, ",
                     ntohs(*(u_int16_t *)p) & 0xfff,
                     ntohs(*(u_int16_t *)p) >> 13,
                     (ntohs(*(u_int16_t *)p) & 0x1000) ? ", CFI" : "");

            ether_type = ntohs(*(u_int16_t *)(p + 2));
            p += 4;
            length -= 4;
            caplen -= 4;

            if (ether_type > ETHERMTU) {
                    if (eflag)
                          printf("ethertype %s, ",
                               tok2str(ethertype_values,"0x%04x", ether_type));
                  goto recurse;
            }

            *extracted_ether_type = 0;

            if (llc_print(p, length, caplen, p - 18, p - 12,
                extracted_ether_type) == 0) {
                        ether_hdr_print(p - 18, length + 4);
            }

            if (!xflag && !qflag)
                    default_print(p - 18, caplen + 4);

            return (1);

      case ETHERTYPE_PPPOED:
      case ETHERTYPE_PPPOES:
            pppoe_print(p, length);
            return (1);

      case ETHERTYPE_PPP:
            if (length) {
                  printf(": ");
                  ppp_print(p, length);
            }
            return (1);

        case ETHERTYPE_LOOPBACK:
                return (0);

      case ETHERTYPE_MPLS:
      case ETHERTYPE_MPLS_MULTI:
            mpls_print(p, length);
            return (1);

      case ETHERTYPE_LAT:
      case ETHERTYPE_SCA:
      case ETHERTYPE_MOPRC:
      case ETHERTYPE_MOPDL:
            /* default_print for now */
      default:
            return (0);
      }
}

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