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 1.79 2003-05-22 14:24:31 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 #include "extract.h"
  41
  42 const u_char *snapend;
  43
  44 static inline void
  45 ether_hdr_print(register const u_char *bp, u_int length)
  46 {
  47         register const struct ether_header *ep;
  48
  49         ep = (const struct ether_header *)bp;
  50
  51         (void)printf("%s > %s",
  52                      etheraddr_string(ESRC(ep)),
  53                      etheraddr_string(EDST(ep)));
  54
  55         if (!qflag) {
  56                 if (ntohs(ep->ether_type) <= ETHERMTU)
  57                           (void)printf(", 802.2");
  58                 else
  59                           (void)printf(", ethertype %s",
  60                                        etherproto_string(ep->ether_type));
  61         }
  62
  63         (void)printf(", length %u: ", length);
  64 }
  65
  66 void
  67 ether_print(const u_char *p, u_int length, u_int caplen)
  68 {
  69         struct ether_header *ep;
  70         u_short ether_type;
  71         u_short extracted_ethertype;
  72
  73         if (caplen < ETHER_HDRLEN) {
  74                 printf("[|ether]");
  75                 return;
  76         }
  77
  78         if (eflag)
  79                 ether_hdr_print(p, length);
  80
  81         length -= ETHER_HDRLEN;
  82         caplen -= ETHER_HDRLEN;
  83         ep = (struct ether_header *)p;
  84         p += ETHER_HDRLEN;
  85
  86         ether_type = ntohs(ep->ether_type);
  87
  88         /*
  89          * Is it (gag) an 802.3 encapsulation?
  90          */
  91         extracted_ethertype = 0;
  92         if (ether_type <= ETHERMTU) {
  93                 /* Try to print the LLC-layer header & higher layers */
  94                 if (llc_print(p, length, caplen, ESRC(ep), EDST(ep),
  95                     &extracted_ethertype) == 0) {
  96                         /* ether_type not known, print raw packet */
  97                         if (!eflag)
  98                                 ether_hdr_print((u_char *)ep, length + ETHER_HDRLEN);
  99                         if (extracted_ethertype) {
 100                                 printf("(LLC %s) ",
 101                                etherproto_string(htons(extracted_ethertype)));
 102                         }
 103                         if (!xflag && !qflag)
 104                                 default_print(p, caplen);
 105                 }
 106         } else if (ether_encap_print(ether_type, p, length, caplen,
 107             &extracted_ethertype) == 0) {
 108                 /* ether_type not known, print raw packet */
 109                 if (!eflag)
 110                         ether_hdr_print((u_char *)ep, length + ETHER_HDRLEN);
 111                 if (!xflag && !qflag)
 112                         default_print(p, caplen);
 113         }
 114 }
 115
 116 /*
 117  * This is the top level routine of the printer.  'p' points
 118  * to the ether header of the packet, 'h->ts' is the timestamp,
 119  * 'h->length' is the length of the packet off the wire, and 'h->caplen'
 120  * is the number of bytes actually captured.
 121  */
 122 u_int
 123 ether_if_print(const struct pcap_pkthdr *h, const u_char *p)
 124 {
 125         ether_print(p, h->len, h->caplen);
 126
 127         return (ETHER_HDRLEN);
 128 }
 129
 130 /*
 131  * Prints the packet encapsulated in an Ethernet data segment
 132  * (or an equivalent encapsulation), given the Ethernet type code.
 133  *
 134  * Returns non-zero if it can do so, zero if the ethertype is unknown.
 135  *
 136  * The Ethernet type code is passed through a pointer; if it was
 137  * ETHERTYPE_8021Q, it gets updated to be the Ethernet type of
 138  * the 802.1Q payload, for the benefit of lower layers that might
 139  * want to know what it is.
 140  */
 141
 142 int
 143 ether_encap_print(u_short ethertype, const u_char *p,
 144     u_int length, u_int caplen, u_short *extracted_ethertype)
 145 {
 146  recurse:
 147         *extracted_ethertype = ethertype;
 148
 149         switch (ethertype) {
 150
 151         case ETHERTYPE_IP:
 152                 ip_print(p, length);
 153                 return (1);
 154
 155 #ifdef INET6
 156         case ETHERTYPE_IPV6:
 157                 ip6_print(p, length);
 158                 return (1);
 159 #endif /*INET6*/
 160
 161         case ETHERTYPE_ARP:
 162         case ETHERTYPE_REVARP:
 163                 arp_print(p, length, caplen);
 164                 return (1);
 165
 166         case ETHERTYPE_DN:
 167                 decnet_print(p, length, caplen);
 168                 return (1);
 169
 170         case ETHERTYPE_ATALK:
 171                 if (vflag)
 172                         fputs("et1 ", stdout);
 173                 atalk_print(p, length);
 174                 return (1);
 175
 176         case ETHERTYPE_AARP:
 177                 aarp_print(p, length);
 178                 return (1);
 179
 180         case ETHERTYPE_IPX:
 181                 printf("(NOV-ETHII) ");
 182                 ipx_print(p, length);
 183                 return (1);
 184
 185         case ETHERTYPE_8021Q:
 186                 printf("802.1Q vlan#%d P%d%s ",
 187                        ntohs(*(u_int16_t *)p) & 0xfff,
 188                        ntohs(*(u_int16_t *)p) >> 13,
 189                        (ntohs(*(u_int16_t *)p) & 0x1000) ? " CFI" : "");
 190                 ethertype = ntohs(*(u_int16_t *)(p + 2));
 191                 p += 4;
 192                 length -= 4;
 193                 caplen -= 4;
 194                 if (ethertype > ETHERMTU)
 195                         goto recurse;
 196
 197                 *extracted_ethertype = 0;
 198
 199                 if (llc_print(p, length, caplen, p - 18, p - 12,
 200                     extracted_ethertype) == 0) {
 201                         /* ether_type not known, print raw packet */
 202                         if (!eflag)
 203                                 ether_hdr_print(p - 18, length + 4);
 204                         if (*extracted_ethertype) {
 205                                 printf("(LLC %s) ",
 206                                etherproto_string(htons(*extracted_ethertype)));
 207                         }
 208                         if (!xflag && !qflag)
 209                                 default_print(p - 18, caplen + 4);
 210                 }
 211                 return (1);
 212
 213         case ETHERTYPE_PPPOED:
 214         case ETHERTYPE_PPPOES:
 215                 pppoe_print(p, length);
 216                 return (1);
 217
 218         case ETHERTYPE_PPP:
 219                 printf("ppp");
 220                 if (length) {
 221                         printf(": ");
 222                         ppp_print(p, length);
 223                 }
 224                 return (1);
 225
 226         case ETHERTYPE_LOOPBACK:
 227                 printf("loopback");
 228                 return (1);
 229
 230         case ETHERTYPE_MPLS:
 231         case ETHERTYPE_MPLS_MULTI:
 232                 mpls_print(p, length);
 233                 return (1);
 234
 235         case ETHERTYPE_LAT:
 236         case ETHERTYPE_SCA:
 237         case ETHERTYPE_MOPRC:
 238         case ETHERTYPE_MOPDL:
 239                 /* default_print for now */
 240         default:
 241                 return (0);
 242         }
 243 }