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 1.78 2003-05-08 14:40:54 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
  48         ep = (const struct ether_header *)bp;
  49         if (qflag)
  50                 (void)printf("%s > %s (length: %u): ",
  51                              etheraddr_string(ESRC(ep)),
  52                              etheraddr_string(EDST(ep)),
  53                              length);
  54         else
  55                 (void)printf("%s > %s %s (length: %u): ",
  56                              etheraddr_string(ESRC(ep)),
  57                              etheraddr_string(EDST(ep)),
  58                              etherproto_string(ep->ether_type),
  59                              length);
  60 }
  61
  62 void
  63 ether_print(const u_char *p, u_int length, u_int caplen)
  64 {
  65         struct ether_header *ep;
  66         u_short ether_type;
  67         u_short extracted_ethertype;
  68
  69         if (caplen < ETHER_HDRLEN) {
  70                 printf("[|ether]");
  71                 return;
  72         }
  73
  74         if (eflag)
  75                 ether_hdr_print(p, length);
  76
  77         length -= ETHER_HDRLEN;
  78         caplen -= ETHER_HDRLEN;
  79         ep = (struct ether_header *)p;
  80         p += ETHER_HDRLEN;
  81
  82         ether_type = ntohs(ep->ether_type);
  83
  84         /*
  85          * Is it (gag) an 802.3 encapsulation?
  86          */
  87         extracted_ethertype = 0;
  88         if (ether_type <= ETHERMTU) {
  89                 /* Try to print the LLC-layer header & higher layers */
  90                 if (llc_print(p, length, caplen, ESRC(ep), EDST(ep),
  91                     &extracted_ethertype) == 0) {
  92                         /* ether_type not known, print raw packet */
  93                         if (!eflag)
  94                                 ether_hdr_print((u_char *)ep, length + ETHER_HDRLEN);
  95                         if (extracted_ethertype) {
  96                                 printf("(LLC %s) ",
  97                                etherproto_string(htons(extracted_ethertype)));
  98                         }
  99                         if (!xflag && !qflag)
 100                                 default_print(p, caplen);
 101                 }
 102         } else if (ether_encap_print(ether_type, p, length, caplen,
 103             &extracted_ethertype) == 0) {
 104                 /* ether_type not known, print raw packet */
 105                 if (!eflag)
 106                         ether_hdr_print((u_char *)ep, length + ETHER_HDRLEN);
 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 ethertype, const u_char *p,
 140     u_int length, u_int caplen, u_short *extracted_ethertype)
 141 {
 142  recurse:
 143         *extracted_ethertype = ethertype;
 144
 145         switch (ethertype) {
 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                 printf("802.1Q vlan#%d P%d%s ",
 183                        ntohs(*(u_int16_t *)p) & 0xfff,
 184                        ntohs(*(u_int16_t *)p) >> 13,
 185                        (ntohs(*(u_int16_t *)p) & 0x1000) ? " CFI" : "");
 186                 ethertype = ntohs(*(u_int16_t *)(p + 2));
 187                 p += 4;
 188                 length -= 4;
 189                 caplen -= 4;
 190                 if (ethertype > ETHERMTU)
 191                         goto recurse;
 192
 193                 *extracted_ethertype = 0;
 194
 195                 if (llc_print(p, length, caplen, p - 18, p - 12,
 196                     extracted_ethertype) == 0) {
 197                         /* ether_type not known, print raw packet */
 198                         if (!eflag)
 199                                 ether_hdr_print(p - 18, length + 4);
 200                         if (*extracted_ethertype) {
 201                                 printf("(LLC %s) ",
 202                                etherproto_string(htons(*extracted_ethertype)));
 203                         }
 204                         if (!xflag && !qflag)
 205                                 default_print(p - 18, caplen + 4);
 206                 }
 207                 return (1);
 208
 209         case ETHERTYPE_PPPOED:
 210         case ETHERTYPE_PPPOES:
 211                 pppoe_print(p, length);
 212                 return (1);
 213
 214         case ETHERTYPE_PPP:
 215                 printf("ppp");
 216                 if (length) {
 217                         printf(": ");
 218                         ppp_print(p, length);
 219                 }
 220                 return (1);
 221
 222         case ETHERTYPE_LOOPBACK:
 223                 printf("loopback");
 224                 return (1);
 225
 226         case ETHERTYPE_MPLS:
 227         case ETHERTYPE_MPLS_MULTI:
 228                 mpls_print(p, length);
 229                 return (1);
 230
 231         case ETHERTYPE_LAT:
 232         case ETHERTYPE_SCA:
 233         case ETHERTYPE_MOPRC:
 234         case ETHERTYPE_MOPDL:
 235                 /* default_print for now */
 236         default:
 237                 return (0);
 238         }
 239 }