The Tcpdump Group git mirrors - tcpdump/blob - print-ether.c

   1 /*
   2  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the University of California,
  13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  */
  21 #ifndef lint
  22 static const char rcsid[] =
  23     "@(#) $Header: /tcpdump/master/tcpdump/print-ether.c,v 1.81 2003-05-28 12:56:52 hannes Exp $ (LBL)";
  24 #endif
  25
  26 #ifdef HAVE_CONFIG_H
  27 #include "config.h"
  28 #endif
  29
  30 #include <tcpdump-stdinc.h>
  31
  32 #include <stdio.h>
  33 #include <pcap.h>
  34
  35 #include "interface.h"
  36 #include "addrtoname.h"
  37 #include "ethertype.h"
  38
  39 #include "ether.h"
  40
  41 const u_char *snapend;
  42
  43 static inline void
  44 ether_hdr_print(register const u_char *bp, u_int length)
  45 {
  46         register const struct ether_header *ep;
  47         ep = (const struct ether_header *)bp;
  48
  49         (void)printf("%s > %s",
  50                      etheraddr_string(ESRC(ep)),
  51                      etheraddr_string(EDST(ep)));
  52
  53         if (!qflag) {
  54                 if (ntohs(ep->ether_type) <= ETHERMTU)
  55                           (void)printf(", 802.3");
  56                 else
  57                           (void)printf(", ethertype %s",
  58                                        tok2str(ethertype_values,"0x%04x", ntohs(ep->ether_type)));
  59         }
  60
  61         (void)printf(", length %u: ", length);
  62 }
  63
  64 void
  65 ether_print(const u_char *p, u_int length, u_int caplen)
  66 {
  67         struct ether_header *ep;
  68         u_short ether_type;
  69         u_short extracted_ether_type;
  70
  71         if (caplen < ETHER_HDRLEN) {
  72                 printf("[|ether]");
  73                 return;
  74         }
  75
  76         if (eflag)
  77                 ether_hdr_print(p, length);
  78
  79         length -= ETHER_HDRLEN;
  80         caplen -= ETHER_HDRLEN;
  81         ep = (struct ether_header *)p;
  82         p += ETHER_HDRLEN;
  83
  84         ether_type = ntohs(ep->ether_type);
  85
  86         /*
  87          * Is it (gag) an 802.3 encapsulation?
  88          */
  89         extracted_ether_type = 0;
  90         if (ether_type <= ETHERMTU) {
  91                 /* Try to print the LLC-layer header & higher layers */
  92                 if (llc_print(p, length, caplen, ESRC(ep), EDST(ep),
  93                     &extracted_ether_type) == 0) {
  94                         /* ether_type not known, print raw packet */
  95                         if (!eflag)
  96                                 ether_hdr_print((u_char *)ep, length + ETHER_HDRLEN);
  97
  98                         if (!xflag && !qflag)
  99                                 default_print(p, caplen);
 100                 }
 101         } else if (ether_encap_print(ether_type, p, length, caplen,
 102             &extracted_ether_type) == 0) {
 103                 /* ether_type not known, print raw packet */
 104                 if (!eflag)
 105                         ether_hdr_print((u_char *)ep, length + ETHER_HDRLEN);
 106
 107                 if (!xflag && !qflag)
 108                         default_print(p, caplen);
 109         }
 110 }
 111
 112 /*
 113  * This is the top level routine of the printer.  'p' points
 114  * to the ether header of the packet, 'h->ts' is the timestamp,
 115  * 'h->length' is the length of the packet off the wire, and 'h->caplen'
 116  * is the number of bytes actually captured.
 117  */
 118 u_int
 119 ether_if_print(const struct pcap_pkthdr *h, const u_char *p)
 120 {
 121         ether_print(p, h->len, h->caplen);
 122
 123         return (ETHER_HDRLEN);
 124 }
 125
 126 /*
 127  * Prints the packet encapsulated in an Ethernet data segment
 128  * (or an equivalent encapsulation), given the Ethernet type code.
 129  *
 130  * Returns non-zero if it can do so, zero if the ethertype is unknown.
 131  *
 132  * The Ethernet type code is passed through a pointer; if it was
 133  * ETHERTYPE_8021Q, it gets updated to be the Ethernet type of
 134  * the 802.1Q payload, for the benefit of lower layers that might
 135  * want to know what it is.
 136  */
 137
 138 int
 139 ether_encap_print(u_short ether_type, const u_char *p,
 140     u_int length, u_int caplen, u_short *extracted_ether_type)
 141 {
 142  recurse:
 143         *extracted_ether_type = ether_type;
 144
 145         switch (ether_type) {
 146
 147         case ETHERTYPE_IP:
 148                 ip_print(p, length);
 149                 return (1);
 150
 151 #ifdef INET6
 152         case ETHERTYPE_IPV6:
 153                 ip6_print(p, length);
 154                 return (1);
 155 #endif /*INET6*/
 156
 157         case ETHERTYPE_ARP:
 158         case ETHERTYPE_REVARP:
 159                 arp_print(p, length, caplen);
 160                 return (1);
 161
 162         case ETHERTYPE_DN:
 163                 decnet_print(p, length, caplen);
 164                 return (1);
 165
 166         case ETHERTYPE_ATALK:
 167                 if (vflag)
 168                         fputs("et1 ", stdout);
 169                 atalk_print(p, length);
 170                 return (1);
 171
 172         case ETHERTYPE_AARP:
 173                 aarp_print(p, length);
 174                 return (1);
 175
 176         case ETHERTYPE_IPX:
 177                 printf("(NOV-ETHII) ");
 178                 ipx_print(p, length);
 179                 return (1);
 180
 181         case ETHERTYPE_8021Q:
 182                 if (eflag)
 183                     printf("vlan %u, p %u%s, ",
 184                            ntohs(*(u_int16_t *)p) & 0xfff,
 185                            ntohs(*(u_int16_t *)p) >> 13,
 186                            (ntohs(*(u_int16_t *)p) & 0x1000) ? ", CFI" : "");
 187
 188                 ether_type = ntohs(*(u_int16_t *)(p + 2));
 189                 p += 4;
 190                 length -= 4;
 191                 caplen -= 4;
 192
 193                 if (ether_type > ETHERMTU) {
 194                         if (eflag)
 195                                 printf("ethertype %s, ",
 196                                        tok2str(ethertype_values,"0x%04x", ether_type));
 197                         goto recurse;
 198                 }
 199
 200                 *extracted_ether_type = 0;
 201
 202                 if (llc_print(p, length, caplen, p - 18, p - 12,
 203                     extracted_ether_type) == 0) {
 204                                 ether_hdr_print(p - 18, length + 4);
 205                 }
 206
 207                 if (!xflag && !qflag)
 208                         default_print(p - 18, caplen + 4);
 209
 210                 return (1);
 211
 212         case ETHERTYPE_PPPOED:
 213         case ETHERTYPE_PPPOES:
 214                 pppoe_print(p, length);
 215                 return (1);
 216
 217         case ETHERTYPE_PPP:
 218                 if (length) {
 219                         printf(": ");
 220                         ppp_print(p, length);
 221                 }
 222                 return (1);
 223
 224         case ETHERTYPE_LOOPBACK:
 225                 return (1);
 226
 227         case ETHERTYPE_MPLS:
 228         case ETHERTYPE_MPLS_MULTI:
 229                 mpls_print(p, length);
 230                 return (1);
 231
 232         case ETHERTYPE_LAT:
 233         case ETHERTYPE_SCA:
 234         case ETHERTYPE_MOPRC:
 235         case ETHERTYPE_MOPDL:
 236                 /* default_print for now */
 237         default:
 238                 return (0);
 239         }
 240 }