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 1.68 2002-05-29 10:06:26 guy Exp $ (LBL)";
  24 #endif
  25
  26 #ifdef HAVE_CONFIG_H
  27 #include "config.h"
  28 #endif
  29
  30 #include <sys/param.h>
  31 #include <sys/time.h>
  32 #include <sys/socket.h>
  33
  34 struct mbuf;
  35 struct rtentry;
  36
  37 #include <netinet/in.h>
  38
  39 #include <stdio.h>
  40 #include <pcap.h>
  41
  42 #include "interface.h"
  43 #include "addrtoname.h"
  44 #include "ethertype.h"
  45
  46 #include "ether.h"
  47
  48 const u_char *packetp;
  49 const u_char *snapend;
  50
  51 static inline void
  52 ether_hdr_print(register const u_char *bp, u_int length)
  53 {
  54         register const struct ether_header *ep;
  55
  56         ep = (const struct ether_header *)bp;
  57         if (qflag)
  58                 (void)printf("%s %s %d: ",
  59                              etheraddr_string(ESRC(ep)),
  60                              etheraddr_string(EDST(ep)),
  61                              length);
  62         else
  63                 (void)printf("%s %s %s %d: ",
  64                              etheraddr_string(ESRC(ep)),
  65                              etheraddr_string(EDST(ep)),
  66                              etherproto_string(ep->ether_type),
  67                              length);
  68 }
  69
  70 void
  71 ether_print(const u_char *p, u_int length, u_int caplen)
  72 {
  73         struct ether_header *ep;
  74         u_short ether_type;
  75         u_short extracted_ethertype;
  76
  77         if (caplen < ETHER_HDRLEN) {
  78                 printf("[|ether]");
  79                 return;
  80         }
  81
  82         if (eflag)
  83                 ether_hdr_print(p, length);
  84
  85         /*
  86          * Some printers want to get back at the ethernet addresses,
  87          * and/or check that they're not walking off the end of the packet.
  88          * Rather than pass them all the way down, we set these globals.
  89          */
  90         packetp = p;
  91         snapend = p + caplen;
  92
  93         length -= ETHER_HDRLEN;
  94         caplen -= ETHER_HDRLEN;
  95         ep = (struct ether_header *)p;
  96         p += ETHER_HDRLEN;
  97
  98         ether_type = ntohs(ep->ether_type);
  99
 100         /*
 101          * Is it (gag) an 802.3 encapsulation?
 102          */
 103         extracted_ethertype = 0;
 104         if (ether_type <= ETHERMTU) {
 105                 /* Try to print the LLC-layer header & higher layers */
 106                 if (llc_print(p, length, caplen, ESRC(ep), EDST(ep),
 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 (extracted_ethertype) {
 112                                 printf("(LLC %s) ",
 113                                etherproto_string(htons(extracted_ethertype)));
 114                         }
 115                         if (!xflag && !qflag)
 116                                 default_print(p, caplen);
 117                 }
 118         } else if (ether_encap_print(ether_type, p, length, caplen,
 119             &extracted_ethertype) == 0) {
 120                 /* ether_type not known, print raw packet */
 121                 if (!eflag)
 122                         ether_hdr_print((u_char *)ep, length + ETHER_HDRLEN);
 123                 if (!xflag && !qflag)
 124                         default_print(p, caplen);
 125         }
 126 }
 127
 128 /*
 129  * This is the top level routine of the printer.  'p' is the points
 130  * to the ether header of the packet, 'h->tv' is the timestamp,
 131  * 'h->length' is the length of the packet off the wire, and 'h->caplen'
 132  * is the number of bytes actually captured.
 133  */
 134 void
 135 ether_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
 136 {
 137         u_int caplen = h->caplen;
 138         u_int length = h->len;
 139
 140         ++infodelay;
 141         ts_print(&h->ts);
 142
 143         ether_print(p, length, caplen);
 144
 145         /*
 146          * If "-x" was specified, print stuff past the Ethernet header,
 147          * if there's anything to print.
 148          */
 149         if (xflag && caplen > ETHER_HDRLEN)
 150                 default_print(p + ETHER_HDRLEN, caplen - ETHER_HDRLEN);
 151
 152         putchar('\n');
 153
 154         --infodelay;
 155         if (infoprint)
 156                 info(0);
 157 }
 158
 159 /*
 160  * Prints the packet encapsulated in an Ethernet data segment
 161  * (or an equivalent encapsulation), given the Ethernet type code.
 162  *
 163  * Returns non-zero if it can do so, zero if the ethertype is unknown.
 164  *
 165  * The Ethernet type code is passed through a pointer; if it was
 166  * ETHERTYPE_8021Q, it gets updated to be the Ethernet type of
 167  * the 802.1Q payload, for the benefit of lower layers that might
 168  * want to know what it is.
 169  */
 170
 171 int
 172 ether_encap_print(u_short ethertype, const u_char *p,
 173     u_int length, u_int caplen, u_short *extracted_ethertype)
 174 {
 175  recurse:
 176         *extracted_ethertype = ethertype;
 177
 178         switch (ethertype) {
 179
 180         case ETHERTYPE_IP:
 181                 ip_print(p, length);
 182                 return (1);
 183
 184 #ifdef INET6
 185         case ETHERTYPE_IPV6:
 186                 ip6_print(p, length);
 187                 return (1);
 188 #endif /*INET6*/
 189
 190         case ETHERTYPE_ARP:
 191         case ETHERTYPE_REVARP:
 192                 arp_print(p, length, caplen);
 193                 return (1);
 194
 195         case ETHERTYPE_DN:
 196                 decnet_print(p, length, caplen);
 197                 return (1);
 198
 199         case ETHERTYPE_ATALK:
 200                 if (vflag)
 201                         fputs("et1 ", stdout);
 202                 atalk_print(p, length);
 203                 return (1);
 204
 205         case ETHERTYPE_AARP:
 206                 aarp_print(p, length);
 207                 return (1);
 208
 209         case ETHERTYPE_IPX:
 210                 printf("(NOV-ETHII) ");
 211                 ipx_print(p, length);
 212                 return (1);
 213
 214         case ETHERTYPE_8021Q:
 215                 printf("802.1Q vlan#%d P%d%s ",
 216                        ntohs(*(u_int16_t *)p) & 0xfff,
 217                        ntohs(*(u_int16_t *)p) >> 13,
 218                        (ntohs(*(u_int16_t *)p) & 0x1000) ? " CFI" : "");
 219                 ethertype = ntohs(*(u_int16_t *)(p + 2));
 220                 p += 4;
 221                 length -= 4;
 222                 caplen -= 4;
 223                 if (ethertype > ETHERMTU)
 224                         goto recurse;
 225
 226                 *extracted_ethertype = 0;
 227
 228                 if (llc_print(p, length, caplen, p - 18, p - 12,
 229                     extracted_ethertype) == 0) {
 230                         /* ether_type not known, print raw packet */
 231                         if (!eflag)
 232                                 ether_hdr_print(p - 18, length + 4);
 233                         if (*extracted_ethertype) {
 234                                 printf("(LLC %s) ",
 235                                etherproto_string(htons(*extracted_ethertype)));
 236                         }
 237                         if (!xflag && !qflag)
 238                                 default_print(p - 18, caplen + 4);
 239                 }
 240                 return (1);
 241
 242         case ETHERTYPE_PPPOED:
 243         case ETHERTYPE_PPPOES:
 244                 pppoe_print(p, length);
 245                 return (1);
 246
 247         case ETHERTYPE_PPP:
 248                 printf("ppp");
 249                 if (length) {
 250                         printf(": ");
 251                         ppp_print(p, length);
 252                 }
 253                 return (1);
 254
 255         case ETHERTYPE_MPLS:
 256         case ETHERTYPE_MPLS_MULTI:
 257                 mpls_print(p, length);
 258                 return (1);
 259
 260         case ETHERTYPE_LAT:
 261         case ETHERTYPE_SCA:
 262         case ETHERTYPE_MOPRC:
 263         case ETHERTYPE_MOPDL:
 264                 /* default_print for now */
 265         default:
 266                 return (0);
 267         }
 268 }