The Tcpdump Group git mirrors - tcpdump/blob - print-ether.c

   1 /*
   2  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
   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 1.63 2001-03-12 00:24:54 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_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 /*
  71  * This is the top level routine of the printer.  'p' is the points
  72  * to the ether header of the packet, 'h->tv' is the timestamp,
  73  * 'h->length' is the length of the packet off the wire, and 'h->caplen'
  74  * is the number of bytes actually captured.
  75  */
  76 void
  77 ether_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
  78 {
  79         u_int caplen = h->caplen;
  80         u_int length = h->len;
  81         struct ether_header *ep;
  82         u_short ether_type;
  83         u_short extracted_ethertype;
  84
  85         ts_print(&h->ts);
  86
  87         if (caplen < ETHER_HDRLEN) {
  88                 printf("[|ether]");
  89                 goto out;
  90         }
  91
  92         if (eflag)
  93                 ether_print(p, length);
  94
  95         /*
  96          * Some printers want to get back at the ethernet addresses,
  97          * and/or check that they're not walking off the end of the packet.
  98          * Rather than pass them all the way down, we set these globals.
  99          */
 100         packetp = p;
 101         snapend = p + caplen;
 102
 103         length -= ETHER_HDRLEN;
 104         caplen -= ETHER_HDRLEN;
 105         ep = (struct ether_header *)p;
 106         p += ETHER_HDRLEN;
 107
 108         ether_type = ntohs(ep->ether_type);
 109
 110         /*
 111          * Is it (gag) an 802.3 encapsulation?
 112          */
 113         extracted_ethertype = 0;
 114         if (ether_type <= ETHERMTU) {
 115                 /* Try to print the LLC-layer header & higher layers */
 116                 if (llc_print(p, length, caplen, ESRC(ep), EDST(ep),
 117                     &extracted_ethertype) == 0) {
 118                         /* ether_type not known, print raw packet */
 119                         if (!eflag)
 120                                 ether_print((u_char *)ep, length + ETHER_HDRLEN);
 121                         if (extracted_ethertype) {
 122                                 printf("(LLC %s) ",
 123                                etherproto_string(htons(extracted_ethertype)));
 124                         }
 125                         if (!xflag && !qflag)
 126                                 default_print(p, caplen);
 127                 }
 128         } else if (ether_encap_print(ether_type, p, length, caplen,
 129             &extracted_ethertype) == 0) {
 130                 /* ether_type not known, print raw packet */
 131                 if (!eflag)
 132                         ether_print((u_char *)ep, length + ETHER_HDRLEN);
 133                 if (!xflag && !qflag)
 134                         default_print(p, caplen);
 135         }
 136         if (xflag)
 137                 default_print(p, caplen);
 138  out:
 139         putchar('\n');
 140 }
 141
 142 /*
 143  * Prints the packet encapsulated in an Ethernet data segment
 144  * (or an equivalent encapsulation), given the Ethernet type code.
 145  *
 146  * Returns non-zero if it can do so, zero if the ethertype is unknown.
 147  *
 148  * The Ethernet type code is passed through a pointer; if it was
 149  * ETHERTYPE_8021Q, it gets updated to be the Ethernet type of
 150  * the 802.1Q payload, for the benefit of lower layers that might
 151  * want to know what it is.
 152  */
 153
 154 int
 155 ether_encap_print(u_short ethertype, const u_char *p,
 156     u_int length, u_int caplen, u_short *extracted_ethertype)
 157 {
 158  recurse:
 159         *extracted_ethertype = ethertype;
 160
 161         switch (ethertype) {
 162
 163         case ETHERTYPE_IP:
 164                 ip_print(p, length);
 165                 return (1);
 166
 167 #ifdef INET6
 168         case ETHERTYPE_IPV6:
 169                 ip6_print(p, length);
 170                 return (1);
 171 #endif /*INET6*/
 172
 173         case ETHERTYPE_ARP:
 174         case ETHERTYPE_REVARP:
 175                 arp_print(p, length, caplen);
 176                 return (1);
 177
 178         case ETHERTYPE_DN:
 179                 decnet_print(p, length, caplen);
 180                 return (1);
 181
 182         case ETHERTYPE_ATALK:
 183                 if (vflag)
 184                         fputs("et1 ", stdout);
 185                 atalk_print(p, length);
 186                 return (1);
 187
 188         case ETHERTYPE_AARP:
 189                 aarp_print(p, length);
 190                 return (1);
 191
 192         case ETHERTYPE_IPX:
 193                 ipx_print(p, length);
 194                 return (1);
 195
 196         case ETHERTYPE_8021Q:
 197                 printf("802.1Q vlan#%d P%d%s ",
 198                        ntohs(*(u_int16_t *)p) & 0xfff,
 199                        ntohs(*(u_int16_t *)p) >> 13,
 200                        (ntohs(*(u_int16_t *)p) & 0x1000) ? " CFI" : "");
 201                 ethertype = ntohs(*(u_int16_t *)(p + 2));
 202                 p += 4;
 203                 length -= 4;
 204                 caplen -= 4;
 205                 if (ethertype > ETHERMTU)
 206                         goto recurse;
 207
 208                 *extracted_ethertype = 0;
 209
 210                 if (llc_print(p, length, caplen, p - 18, p - 12,
 211                     extracted_ethertype) == 0) {
 212                         /* ether_type not known, print raw packet */
 213                         if (!eflag)
 214                                 ether_print(p - 18, length + 4);
 215                         if (*extracted_ethertype) {
 216                                 printf("(LLC %s) ",
 217                                etherproto_string(htons(*extracted_ethertype)));
 218                         }
 219                         if (!xflag && !qflag)
 220                                 default_print(p - 18, caplen + 4);
 221                 }
 222                 return (1);
 223
 224         case ETHERTYPE_PPPOED:
 225         case ETHERTYPE_PPPOES:
 226                 pppoe_print(p, length);
 227                 return (1);
 228
 229         case ETHERTYPE_PPP:
 230                 printf("ppp");
 231                 if (length) {
 232                         printf(": ");
 233                         ppp_print(p, length);
 234                 }
 235                 return (1);
 236
 237         case ETHERTYPE_LAT:
 238         case ETHERTYPE_SCA:
 239         case ETHERTYPE_MOPRC:
 240         case ETHERTYPE_MOPDL:
 241                 /* default_print for now */
 242         default:
 243                 return (0);
 244         }
 245 }