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 1.73 2002-09-05 21:25:40 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 *packetp;
  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         if (qflag)
  51                 (void)printf("%s %s %d: ",
  52                              etheraddr_string(ESRC(ep)),
  53                              etheraddr_string(EDST(ep)),
  54                              length);
  55         else
  56                 (void)printf("%s %s %s %d: ",
  57                              etheraddr_string(ESRC(ep)),
  58                              etheraddr_string(EDST(ep)),
  59                              etherproto_string(ep->ether_type),
  60                              length);
  61 }
  62
  63 void
  64 ether_print(const u_char *p, u_int length, u_int caplen)
  65 {
  66         struct ether_header *ep;
  67         u_short ether_type;
  68         u_short extracted_ethertype;
  69
  70         if (caplen < ETHER_HDRLEN) {
  71                 printf("[|ether]");
  72                 return;
  73         }
  74
  75         if (eflag)
  76                 ether_hdr_print(p, length);
  77
  78         /*
  79          * Some printers want to get back at the ethernet addresses,
  80          * and/or check that they're not walking off the end of the packet.
  81          * Rather than pass them all the way down, we set these globals.
  82          */
  83         packetp = p;
  84         snapend = p + caplen;
  85
  86         length -= ETHER_HDRLEN;
  87         caplen -= ETHER_HDRLEN;
  88         ep = (struct ether_header *)p;
  89         p += ETHER_HDRLEN;
  90
  91         ether_type = ntohs(ep->ether_type);
  92
  93         /*
  94          * Is it (gag) an 802.3 encapsulation?
  95          */
  96         extracted_ethertype = 0;
  97         if (ether_type <= ETHERMTU) {
  98                 /* Try to print the LLC-layer header & higher layers */
  99                 if (llc_print(p, length, caplen, ESRC(ep), EDST(ep),
 100                     &extracted_ethertype) == 0) {
 101                         /* ether_type not known, print raw packet */
 102                         if (!eflag)
 103                                 ether_hdr_print((u_char *)ep, length + ETHER_HDRLEN);
 104                         if (extracted_ethertype) {
 105                                 printf("(LLC %s) ",
 106                                etherproto_string(htons(extracted_ethertype)));
 107                         }
 108                         if (!xflag && !qflag)
 109                                 default_print(p, caplen);
 110                 }
 111         } else if (ether_encap_print(ether_type, p, length, caplen,
 112             &extracted_ethertype) == 0) {
 113                 /* ether_type not known, print raw packet */
 114                 if (!eflag)
 115                         ether_hdr_print((u_char *)ep, length + ETHER_HDRLEN);
 116                 if (!xflag && !qflag)
 117                         default_print(p, caplen);
 118         }
 119 }
 120
 121 /*
 122  * This is the top level routine of the printer.  'p' points
 123  * to the ether header of the packet, 'h->ts' is the timestamp,
 124  * 'h->length' is the length of the packet off the wire, and 'h->caplen'
 125  * is the number of bytes actually captured.
 126  */
 127 void
 128 ether_if_print(u_char *user _U_, const struct pcap_pkthdr *h, const u_char *p)
 129 {
 130         u_int caplen = h->caplen;
 131         u_int length = h->len;
 132
 133         ++infodelay;
 134         ts_print(&h->ts);
 135
 136         ether_print(p, length, caplen);
 137
 138         /*
 139          * If "-x" was specified, print stuff past the Ethernet header,
 140          * if there's anything to print.
 141          */
 142         if (xflag && caplen > ETHER_HDRLEN)
 143                 default_print(p + ETHER_HDRLEN, caplen - ETHER_HDRLEN);
 144
 145         putchar('\n');
 146
 147         --infodelay;
 148         if (infoprint)
 149                 info(0);
 150 }
 151
 152 /*
 153  * Prints the packet encapsulated in an Ethernet data segment
 154  * (or an equivalent encapsulation), given the Ethernet type code.
 155  *
 156  * Returns non-zero if it can do so, zero if the ethertype is unknown.
 157  *
 158  * The Ethernet type code is passed through a pointer; if it was
 159  * ETHERTYPE_8021Q, it gets updated to be the Ethernet type of
 160  * the 802.1Q payload, for the benefit of lower layers that might
 161  * want to know what it is.
 162  */
 163
 164 int
 165 ether_encap_print(u_short ethertype, const u_char *p,
 166     u_int length, u_int caplen, u_short *extracted_ethertype)
 167 {
 168  recurse:
 169         *extracted_ethertype = ethertype;
 170
 171         switch (ethertype) {
 172
 173         case ETHERTYPE_IP:
 174                 ip_print(p, length);
 175                 return (1);
 176
 177 #ifdef INET6
 178         case ETHERTYPE_IPV6:
 179                 ip6_print(p, length);
 180                 return (1);
 181 #endif /*INET6*/
 182
 183         case ETHERTYPE_ARP:
 184         case ETHERTYPE_REVARP:
 185                 arp_print(p, length, caplen);
 186                 return (1);
 187
 188         case ETHERTYPE_DN:
 189                 decnet_print(p, length, caplen);
 190                 return (1);
 191
 192         case ETHERTYPE_ATALK:
 193                 if (vflag)
 194                         fputs("et1 ", stdout);
 195                 atalk_print(p, length);
 196                 return (1);
 197
 198         case ETHERTYPE_AARP:
 199                 aarp_print(p, length);
 200                 return (1);
 201
 202         case ETHERTYPE_IPX:
 203                 printf("(NOV-ETHII) ");
 204                 ipx_print(p, length);
 205                 return (1);
 206
 207         case ETHERTYPE_8021Q:
 208                 printf("802.1Q vlan#%d P%d%s ",
 209                        ntohs(*(u_int16_t *)p) & 0xfff,
 210                        ntohs(*(u_int16_t *)p) >> 13,
 211                        (ntohs(*(u_int16_t *)p) & 0x1000) ? " CFI" : "");
 212                 ethertype = ntohs(*(u_int16_t *)(p + 2));
 213                 p += 4;
 214                 length -= 4;
 215                 caplen -= 4;
 216                 if (ethertype > ETHERMTU)
 217                         goto recurse;
 218
 219                 *extracted_ethertype = 0;
 220
 221                 if (llc_print(p, length, caplen, p - 18, p - 12,
 222                     extracted_ethertype) == 0) {
 223                         /* ether_type not known, print raw packet */
 224                         if (!eflag)
 225                                 ether_hdr_print(p - 18, length + 4);
 226                         if (*extracted_ethertype) {
 227                                 printf("(LLC %s) ",
 228                                etherproto_string(htons(*extracted_ethertype)));
 229                         }
 230                         if (!xflag && !qflag)
 231                                 default_print(p - 18, caplen + 4);
 232                 }
 233                 return (1);
 234
 235         case ETHERTYPE_PPPOED:
 236         case ETHERTYPE_PPPOES:
 237                 pppoe_print(p, length);
 238                 return (1);
 239
 240         case ETHERTYPE_PPP:
 241                 printf("ppp");
 242                 if (length) {
 243                         printf(": ");
 244                         ppp_print(p, length);
 245                 }
 246                 return (1);
 247
 248         case ETHERTYPE_LOOPBACK:
 249                 printf("loopback");
 250                 return (1);
 251
 252         case ETHERTYPE_MPLS:
 253         case ETHERTYPE_MPLS_MULTI:
 254                 mpls_print(p, length);
 255                 return (1);
 256
 257         case ETHERTYPE_LAT:
 258         case ETHERTYPE_SCA:
 259         case ETHERTYPE_MOPRC:
 260         case ETHERTYPE_MOPDL:
 261                 /* default_print for now */
 262         default:
 263                 return (0);
 264         }
 265 }