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 1.75 2002-12-18 09:41:15 guy 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 %d: ",
  51                              etheraddr_string(ESRC(ep)),
  52                              etheraddr_string(EDST(ep)),
  53                              length);
  54         else
  55                 (void)printf("%s %s %s %d: ",
  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         /*
  78          * Some printers want to check that they're not walking off the
  79          * end of the packet.
  80          * Rather than pass it all the way down, we set this global.
  81          */
  82         snapend = p + caplen;
  83
  84         length -= ETHER_HDRLEN;
  85         caplen -= ETHER_HDRLEN;
  86         ep = (struct ether_header *)p;
  87         p += ETHER_HDRLEN;
  88
  89         ether_type = ntohs(ep->ether_type);
  90
  91         /*
  92          * Is it (gag) an 802.3 encapsulation?
  93          */
  94         extracted_ethertype = 0;
  95         if (ether_type <= ETHERMTU) {
  96                 /* Try to print the LLC-layer header & higher layers */
  97                 if (llc_print(p, length, caplen, ESRC(ep), EDST(ep),
  98                     &extracted_ethertype) == 0) {
  99                         /* ether_type not known, print raw packet */
 100                         if (!eflag)
 101                                 ether_hdr_print((u_char *)ep, length + ETHER_HDRLEN);
 102                         if (extracted_ethertype) {
 103                                 printf("(LLC %s) ",
 104                                etherproto_string(htons(extracted_ethertype)));
 105                         }
 106                         if (!xflag && !qflag)
 107                                 default_print(p, caplen);
 108                 }
 109         } else if (ether_encap_print(ether_type, p, length, caplen,
 110             &extracted_ethertype) == 0) {
 111                 /* ether_type not known, print raw packet */
 112                 if (!eflag)
 113                         ether_hdr_print((u_char *)ep, length + ETHER_HDRLEN);
 114                 if (!xflag && !qflag)
 115                         default_print(p, caplen);
 116         }
 117 }
 118
 119 /*
 120  * This is the top level routine of the printer.  'p' points
 121  * to the ether header of the packet, 'h->ts' is the timestamp,
 122  * 'h->length' is the length of the packet off the wire, and 'h->caplen'
 123  * is the number of bytes actually captured.
 124  */
 125 void
 126 ether_if_print(u_char *user _U_, const struct pcap_pkthdr *h, const u_char *p)
 127 {
 128         u_int caplen = h->caplen;
 129         u_int length = h->len;
 130
 131         ++infodelay;
 132         ts_print(&h->ts);
 133
 134         ether_print(p, length, caplen);
 135
 136         /*
 137          * If "-x" was specified, print packet data in hex.
 138          */
 139         if (xflag)
 140                 default_print_packet(p, caplen, ETHER_HDRLEN);
 141
 142         putchar('\n');
 143
 144         --infodelay;
 145         if (infoprint)
 146                 info(0);
 147 }
 148
 149 /*
 150  * Prints the packet encapsulated in an Ethernet data segment
 151  * (or an equivalent encapsulation), given the Ethernet type code.
 152  *
 153  * Returns non-zero if it can do so, zero if the ethertype is unknown.
 154  *
 155  * The Ethernet type code is passed through a pointer; if it was
 156  * ETHERTYPE_8021Q, it gets updated to be the Ethernet type of
 157  * the 802.1Q payload, for the benefit of lower layers that might
 158  * want to know what it is.
 159  */
 160
 161 int
 162 ether_encap_print(u_short ethertype, const u_char *p,
 163     u_int length, u_int caplen, u_short *extracted_ethertype)
 164 {
 165  recurse:
 166         *extracted_ethertype = ethertype;
 167
 168         switch (ethertype) {
 169
 170         case ETHERTYPE_IP:
 171                 ip_print(p, length);
 172                 return (1);
 173
 174 #ifdef INET6
 175         case ETHERTYPE_IPV6:
 176                 ip6_print(p, length);
 177                 return (1);
 178 #endif /*INET6*/
 179
 180         case ETHERTYPE_ARP:
 181         case ETHERTYPE_REVARP:
 182                 arp_print(p, length, caplen);
 183                 return (1);
 184
 185         case ETHERTYPE_DN:
 186                 decnet_print(p, length, caplen);
 187                 return (1);
 188
 189         case ETHERTYPE_ATALK:
 190                 if (vflag)
 191                         fputs("et1 ", stdout);
 192                 atalk_print(p, length);
 193                 return (1);
 194
 195         case ETHERTYPE_AARP:
 196                 aarp_print(p, length);
 197                 return (1);
 198
 199         case ETHERTYPE_IPX:
 200                 printf("(NOV-ETHII) ");
 201                 ipx_print(p, length);
 202                 return (1);
 203
 204         case ETHERTYPE_8021Q:
 205                 printf("802.1Q vlan#%d P%d%s ",
 206                        ntohs(*(u_int16_t *)p) & 0xfff,
 207                        ntohs(*(u_int16_t *)p) >> 13,
 208                        (ntohs(*(u_int16_t *)p) & 0x1000) ? " CFI" : "");
 209                 ethertype = ntohs(*(u_int16_t *)(p + 2));
 210                 p += 4;
 211                 length -= 4;
 212                 caplen -= 4;
 213                 if (ethertype > ETHERMTU)
 214                         goto recurse;
 215
 216                 *extracted_ethertype = 0;
 217
 218                 if (llc_print(p, length, caplen, p - 18, p - 12,
 219                     extracted_ethertype) == 0) {
 220                         /* ether_type not known, print raw packet */
 221                         if (!eflag)
 222                                 ether_hdr_print(p - 18, length + 4);
 223                         if (*extracted_ethertype) {
 224                                 printf("(LLC %s) ",
 225                                etherproto_string(htons(*extracted_ethertype)));
 226                         }
 227                         if (!xflag && !qflag)
 228                                 default_print(p - 18, caplen + 4);
 229                 }
 230                 return (1);
 231
 232         case ETHERTYPE_PPPOED:
 233         case ETHERTYPE_PPPOES:
 234                 pppoe_print(p, length);
 235                 return (1);
 236
 237         case ETHERTYPE_PPP:
 238                 printf("ppp");
 239                 if (length) {
 240                         printf(": ");
 241                         ppp_print(p, length);
 242                 }
 243                 return (1);
 244
 245         case ETHERTYPE_LOOPBACK:
 246                 printf("loopback");
 247                 return (1);
 248
 249         case ETHERTYPE_MPLS:
 250         case ETHERTYPE_MPLS_MULTI:
 251                 mpls_print(p, length);
 252                 return (1);
 253
 254         case ETHERTYPE_LAT:
 255         case ETHERTYPE_SCA:
 256         case ETHERTYPE_MOPRC:
 257         case ETHERTYPE_MOPDL:
 258                 /* default_print for now */
 259         default:
 260                 return (0);
 261         }
 262 }