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 1.58 2000-10-09 02:59:39 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 static u_short extracted_ethertype;
  71
  72 /*
  73  * This is the top level routine of the printer.  'p' is the points
  74  * to the ether header of the packet, 'h->tv' is the timestamp,
  75  * 'h->length' is the length of the packet off the wire, and 'h->caplen'
  76  * is the number of bytes actually captured.
  77  */
  78 void
  79 ether_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
  80 {
  81         u_int caplen = h->caplen;
  82         u_int length = h->len;
  83         struct ether_header *ep;
  84         u_short ether_type;
  85
  86         ts_print(&h->ts);
  87
  88         if (caplen < ETHER_HDRLEN) {
  89                 printf("[|ether]");
  90                 goto out;
  91         }
  92
  93         if (eflag)
  94                 ether_print(p, length);
  95
  96         /*
  97          * Some printers want to get back at the ethernet addresses,
  98          * and/or check that they're not walking off the end of the packet.
  99          * Rather than pass them all the way down, we set these globals.
 100          */
 101         packetp = p;
 102         snapend = p + caplen;
 103
 104         length -= ETHER_HDRLEN;
 105         caplen -= ETHER_HDRLEN;
 106         ep = (struct ether_header *)p;
 107         p += ETHER_HDRLEN;
 108
 109         ether_type = ntohs(ep->ether_type);
 110
 111         /*
 112          * Is it (gag) an 802.3 encapsulation?
 113          */
 114         extracted_ethertype = 0;
 115         if (ether_type <= ETHERMTU) {
 116                 /* Try to print the LLC-layer header & higher layers */
 117                 if (llc_print(p, length, caplen, ESRC(ep), EDST(ep)) == 0) {
 118                         /* ether_type not known, print raw packet */
 119                         if (!eflag)
 120                                 ether_print((u_char *)ep, length);
 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) == 0) {
 129                 /* ether_type not known, print raw packet */
 130                 if (!eflag)
 131                         ether_print((u_char *)ep, length + ETHER_HDRLEN);
 132                 if (!xflag && !qflag)
 133                         default_print(p, caplen);
 134         }
 135         if (xflag)
 136                 default_print(p, caplen);
 137  out:
 138         putchar('\n');
 139 }
 140
 141 /*
 142  * Prints the packet encapsulated in an Ethernet data segment
 143  * (or an equivalent encapsulation), given the Ethernet type code.
 144  *
 145  * Returns non-zero if it can do so, zero if the ethertype is unknown.
 146  *
 147  * Stuffs the ether type into a global for the benefit of lower layers
 148  * that might want to know what it is.
 149  */
 150
 151 int
 152 ether_encap_print(u_short ethertype, const u_char *p,
 153     u_int length, u_int caplen)
 154 {
 155  recurse:
 156         extracted_ethertype = ethertype;
 157
 158         switch (ethertype) {
 159
 160         case ETHERTYPE_IP:
 161                 ip_print(p, length);
 162                 return (1);
 163
 164 #ifdef INET6
 165         case ETHERTYPE_IPV6:
 166                 ip6_print(p, length);
 167                 return (1);
 168 #endif /*INET6*/
 169
 170         case ETHERTYPE_ARP:
 171         case ETHERTYPE_REVARP:
 172                 arp_print(p, length, caplen);
 173                 return (1);
 174
 175         case ETHERTYPE_DN:
 176                 decnet_print(p, length, caplen);
 177                 return (1);
 178
 179         case ETHERTYPE_ATALK:
 180                 if (vflag)
 181                         fputs("et1 ", stdout);
 182                 atalk_print(p, length);
 183                 return (1);
 184
 185         case ETHERTYPE_AARP:
 186                 aarp_print(p, length);
 187                 return (1);
 188
 189         case ETHERTYPE_IPX:
 190                 ipx_print(p, length);
 191                 return (1);
 192
 193         case ETHERTYPE_8021Q:
 194                 printf("802.1Q vlan#%d P%d%s",
 195                        ntohs(*(u_int16_t *)p) & 0xfff,
 196                        ntohs(*(u_int16_t *)p) >> 13,
 197                        (ntohs(*(u_int16_t *)p) & 0x1000) ? " CFI" : "");
 198                 ethertype = ntohs(*(u_int16_t *)(p + 2));
 199                 p += 4;
 200                 length -= 4;
 201                 caplen -= 4;
 202                 if (ethertype > ETHERMTU)
 203                         goto recurse;
 204
 205                 extracted_ethertype = 0;
 206
 207                 if (llc_print(p, length, caplen, p - 18, p - 12) == 0) {
 208                         /* ether_type not known, print raw packet */
 209                         if (!eflag)
 210                                 ether_print(p - 18, length + 4);
 211                         if (extracted_ethertype) {
 212                                 printf("(LLC %s) ",
 213                                etherproto_string(htons(extracted_ethertype)));
 214                         }
 215                         if (!xflag && !qflag)
 216                                 default_print(p - 18, caplen + 4);
 217                 }
 218                 return (1);
 219
 220         case ETHERTYPE_PPPOED:
 221         case ETHERTYPE_PPPOES:
 222                 pppoe_print(p, length);
 223                 return (1);
 224
 225         case ETHERTYPE_LAT:
 226         case ETHERTYPE_SCA:
 227         case ETHERTYPE_MOPRC:
 228         case ETHERTYPE_MOPDL:
 229                 /* default_print for now */
 230         default:
 231                 return (0);
 232         }
 233 }