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 1.54 2000-09-23 08:54:28 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 #include <net/if.h>
  37
  38 #include <netinet/in.h>
  39 #include <netinet/in_systm.h>
  40
  41 #include <stdio.h>
  42 #include <pcap.h>
  43
  44 #ifdef INET6
  45 #include <netinet/ip6.h>
  46 #endif
  47
  48 #include "interface.h"
  49 #include "addrtoname.h"
  50 #include "ethertype.h"
  51
  52 #include "ether.h"
  53
  54 const u_char *packetp;
  55 const u_char *snapend;
  56
  57 static inline void
  58 ether_print(register const u_char *bp, u_int length)
  59 {
  60         register const struct ether_header *ep;
  61
  62         ep = (const struct ether_header *)bp;
  63         if (qflag)
  64                 (void)printf("%s %s %d: ",
  65                              etheraddr_string(ESRC(ep)),
  66                              etheraddr_string(EDST(ep)),
  67                              length);
  68         else
  69                 (void)printf("%s %s %s %d: ",
  70                              etheraddr_string(ESRC(ep)),
  71                              etheraddr_string(EDST(ep)),
  72                              etherproto_string(ep->ether_type),
  73                              length);
  74 }
  75
  76 static u_short extracted_ethertype;
  77
  78 /*
  79  * This is the top level routine of the printer.  'p' is the points
  80  * to the ether header of the packet, 'h->tv' is the timestamp,
  81  * 'h->length' is the length of the packet off the wire, and 'h->caplen'
  82  * is the number of bytes actually captured.
  83  */
  84 void
  85 ether_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
  86 {
  87         u_int caplen = h->caplen;
  88         u_int length = h->len;
  89         struct ether_header *ep;
  90         u_short ether_type;
  91
  92         ts_print(&h->ts);
  93
  94         if (caplen < sizeof(struct ether_header)) {
  95                 printf("[|ether]");
  96                 goto out;
  97         }
  98
  99         if (eflag)
 100                 ether_print(p, length);
 101
 102         /*
 103          * Some printers want to get back at the ethernet addresses,
 104          * and/or check that they're not walking off the end of the packet.
 105          * Rather than pass them all the way down, we set these globals.
 106          */
 107         packetp = p;
 108         snapend = p + caplen;
 109
 110         length -= sizeof(struct ether_header);
 111         caplen -= sizeof(struct ether_header);
 112         ep = (struct ether_header *)p;
 113         p += sizeof(struct ether_header);
 114
 115         ether_type = ntohs(ep->ether_type);
 116
 117         /*
 118          * Is it (gag) an 802.3 encapsulation?
 119          */
 120         extracted_ethertype = 0;
 121         if (ether_type <= ETHERMTU) {
 122                 /* Try to print the LLC-layer header & higher layers */
 123                 if (llc_print(p, length, caplen, ESRC(ep), EDST(ep)) == 0) {
 124                         /* ether_type not known, print raw packet */
 125                         if (!eflag)
 126                                 ether_print((u_char *)ep, length);
 127                         if (extracted_ethertype) {
 128                                 printf("(LLC %s) ",
 129                                etherproto_string(htons(extracted_ethertype)));
 130                         }
 131                         if (!xflag && !qflag)
 132                                 default_print(p, caplen);
 133                 }
 134         } else if (ether_encap_print(ether_type, p, length, caplen) == 0) {
 135                 /* ether_type not known, print raw packet */
 136                 if (!eflag)
 137                         ether_print((u_char *)ep, length + sizeof(*ep));
 138                 if (!xflag && !qflag)
 139                         default_print(p, caplen);
 140         }
 141         if (xflag)
 142                 default_print(p, caplen);
 143  out:
 144         putchar('\n');
 145 }
 146
 147 /*
 148  * Prints the packet encapsulated in an Ethernet data segment
 149  * (or an equivalent encapsulation), given the Ethernet type code.
 150  *
 151  * Returns non-zero if it can do so, zero if the ethertype is unknown.
 152  *
 153  * Stuffs the ether type into a global for the benefit of lower layers
 154  * that might want to know what it is.
 155  */
 156
 157 int
 158 ether_encap_print(u_short ethertype, const u_char *p,
 159     u_int length, u_int caplen)
 160 {
 161  recurse:
 162         extracted_ethertype = ethertype;
 163
 164         switch (ethertype) {
 165
 166         case ETHERTYPE_IP:
 167                 ip_print(p, length);
 168                 return (1);
 169
 170 #ifdef INET6
 171         case ETHERTYPE_IPV6:
 172                 ip6_print(p, length);
 173                 return (1);
 174 #endif /*INET6*/
 175
 176         case ETHERTYPE_ARP:
 177         case ETHERTYPE_REVARP:
 178                 arp_print(p, length, caplen);
 179                 return (1);
 180
 181         case ETHERTYPE_DN:
 182                 decnet_print(p, length, caplen);
 183                 return (1);
 184
 185         case ETHERTYPE_ATALK:
 186                 if (vflag)
 187                         fputs("et1 ", stdout);
 188                 atalk_print(p, length);
 189                 return (1);
 190
 191         case ETHERTYPE_AARP:
 192                 aarp_print(p, length);
 193                 return (1);
 194
 195         case ETHERTYPE_IPX:
 196                 ipx_print(p, length);
 197                 return (1);
 198
 199         case ETHERTYPE_8021Q:
 200                 printf("802.1Q vlan#%d P%d%s",
 201                        ntohs(*(u_int16_t *)p) & 0xfff,
 202                        ntohs(*(u_int16_t *)p) >> 13,
 203                        (ntohs(*(u_int16_t *)p) & 0x1000) ? " CFI" : "");
 204                 ethertype = ntohs(*(u_int16_t *)(p + 2));
 205                 p += 4;
 206                 length -= 4;
 207                 caplen -= 4;
 208                 if (ethertype > ETHERMTU)
 209                         goto recurse;
 210
 211                 extracted_ethertype = 0;
 212
 213                 if (llc_print(p, length, caplen, p - 18, p - 12) == 0) {
 214                         /* ether_type not known, print raw packet */
 215                         if (!eflag)
 216                                 ether_print(p - 18, length + 4);
 217                         if (extracted_ethertype) {
 218                                 printf("(LLC %s) ",
 219                                etherproto_string(htons(extracted_ethertype)));
 220                         }
 221                         if (!xflag && !qflag)
 222                                 default_print(p - 18, caplen + 4);
 223                 }
 224                 return (1);
 225
 226         case ETHERTYPE_PPPOED:
 227         case ETHERTYPE_PPPOES:
 228                 pppoe_print(p, length);
 229                 return (1);
 230
 231         case ETHERTYPE_LAT:
 232         case ETHERTYPE_SCA:
 233         case ETHERTYPE_MOPRC:
 234         case ETHERTYPE_MOPDL:
 235                 /* default_print for now */
 236         default:
 237                 return (0);
 238         }
 239 }