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 1.55 2000-09-28 06:42:59 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 #include <netinet/in_systm.h>
  39
  40 #include <stdio.h>
  41 #include <pcap.h>
  42
  43 #ifdef INET6
  44 #include <netinet/ip6.h>
  45 #endif
  46
  47 #include "interface.h"
  48 #include "addrtoname.h"
  49 #include "ethertype.h"
  50
  51 #include "ether.h"
  52
  53 const u_char *packetp;
  54 const u_char *snapend;
  55
  56 static inline void
  57 ether_print(register const u_char *bp, u_int length)
  58 {
  59         register const struct ether_header *ep;
  60
  61         ep = (const struct ether_header *)bp;
  62         if (qflag)
  63                 (void)printf("%s %s %d: ",
  64                              etheraddr_string(ESRC(ep)),
  65                              etheraddr_string(EDST(ep)),
  66                              length);
  67         else
  68                 (void)printf("%s %s %s %d: ",
  69                              etheraddr_string(ESRC(ep)),
  70                              etheraddr_string(EDST(ep)),
  71                              etherproto_string(ep->ether_type),
  72                              length);
  73 }
  74
  75 static u_short extracted_ethertype;
  76
  77 /*
  78  * This is the top level routine of the printer.  'p' is the points
  79  * to the ether header of the packet, 'h->tv' is the timestamp,
  80  * 'h->length' is the length of the packet off the wire, and 'h->caplen'
  81  * is the number of bytes actually captured.
  82  */
  83 void
  84 ether_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
  85 {
  86         u_int caplen = h->caplen;
  87         u_int length = h->len;
  88         struct ether_header *ep;
  89         u_short ether_type;
  90
  91         ts_print(&h->ts);
  92
  93         if (caplen < sizeof(struct ether_header)) {
  94                 printf("[|ether]");
  95                 goto out;
  96         }
  97
  98         if (eflag)
  99                 ether_print(p, length);
 100
 101         /*
 102          * Some printers want to get back at the ethernet addresses,
 103          * and/or check that they're not walking off the end of the packet.
 104          * Rather than pass them all the way down, we set these globals.
 105          */
 106         packetp = p;
 107         snapend = p + caplen;
 108
 109         length -= sizeof(struct ether_header);
 110         caplen -= sizeof(struct ether_header);
 111         ep = (struct ether_header *)p;
 112         p += sizeof(struct ether_header);
 113
 114         ether_type = ntohs(ep->ether_type);
 115
 116         /*
 117          * Is it (gag) an 802.3 encapsulation?
 118          */
 119         extracted_ethertype = 0;
 120         if (ether_type <= ETHERMTU) {
 121                 /* Try to print the LLC-layer header & higher layers */
 122                 if (llc_print(p, length, caplen, ESRC(ep), EDST(ep)) == 0) {
 123                         /* ether_type not known, print raw packet */
 124                         if (!eflag)
 125                                 ether_print((u_char *)ep, length);
 126                         if (extracted_ethertype) {
 127                                 printf("(LLC %s) ",
 128                                etherproto_string(htons(extracted_ethertype)));
 129                         }
 130                         if (!xflag && !qflag)
 131                                 default_print(p, caplen);
 132                 }
 133         } else if (ether_encap_print(ether_type, p, length, caplen) == 0) {
 134                 /* ether_type not known, print raw packet */
 135                 if (!eflag)
 136                         ether_print((u_char *)ep, length + sizeof(*ep));
 137                 if (!xflag && !qflag)
 138                         default_print(p, caplen);
 139         }
 140         if (xflag)
 141                 default_print(p, caplen);
 142  out:
 143         putchar('\n');
 144 }
 145
 146 /*
 147  * Prints the packet encapsulated in an Ethernet data segment
 148  * (or an equivalent encapsulation), given the Ethernet type code.
 149  *
 150  * Returns non-zero if it can do so, zero if the ethertype is unknown.
 151  *
 152  * Stuffs the ether type into a global for the benefit of lower layers
 153  * that might want to know what it is.
 154  */
 155
 156 int
 157 ether_encap_print(u_short ethertype, const u_char *p,
 158     u_int length, u_int caplen)
 159 {
 160  recurse:
 161         extracted_ethertype = ethertype;
 162
 163         switch (ethertype) {
 164
 165         case ETHERTYPE_IP:
 166                 ip_print(p, length);
 167                 return (1);
 168
 169 #ifdef INET6
 170         case ETHERTYPE_IPV6:
 171                 ip6_print(p, length);
 172                 return (1);
 173 #endif /*INET6*/
 174
 175         case ETHERTYPE_ARP:
 176         case ETHERTYPE_REVARP:
 177                 arp_print(p, length, caplen);
 178                 return (1);
 179
 180         case ETHERTYPE_DN:
 181                 decnet_print(p, length, caplen);
 182                 return (1);
 183
 184         case ETHERTYPE_ATALK:
 185                 if (vflag)
 186                         fputs("et1 ", stdout);
 187                 atalk_print(p, length);
 188                 return (1);
 189
 190         case ETHERTYPE_AARP:
 191                 aarp_print(p, length);
 192                 return (1);
 193
 194         case ETHERTYPE_IPX:
 195                 ipx_print(p, length);
 196                 return (1);
 197
 198         case ETHERTYPE_8021Q:
 199                 printf("802.1Q vlan#%d P%d%s",
 200                        ntohs(*(u_int16_t *)p) & 0xfff,
 201                        ntohs(*(u_int16_t *)p) >> 13,
 202                        (ntohs(*(u_int16_t *)p) & 0x1000) ? " CFI" : "");
 203                 ethertype = ntohs(*(u_int16_t *)(p + 2));
 204                 p += 4;
 205                 length -= 4;
 206                 caplen -= 4;
 207                 if (ethertype > ETHERMTU)
 208                         goto recurse;
 209
 210                 extracted_ethertype = 0;
 211
 212                 if (llc_print(p, length, caplen, p - 18, p - 12) == 0) {
 213                         /* ether_type not known, print raw packet */
 214                         if (!eflag)
 215                                 ether_print(p - 18, length + 4);
 216                         if (extracted_ethertype) {
 217                                 printf("(LLC %s) ",
 218                                etherproto_string(htons(extracted_ethertype)));
 219                         }
 220                         if (!xflag && !qflag)
 221                                 default_print(p - 18, caplen + 4);
 222                 }
 223                 return (1);
 224
 225         case ETHERTYPE_PPPOED:
 226         case ETHERTYPE_PPPOES:
 227                 pppoe_print(p, length);
 228                 return (1);
 229
 230         case ETHERTYPE_LAT:
 231         case ETHERTYPE_SCA:
 232         case ETHERTYPE_MOPRC:
 233         case ETHERTYPE_MOPDL:
 234                 /* default_print for now */
 235         default:
 236                 return (0);
 237         }
 238 }