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 1.53 2000-09-23 08:26:33 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 #include <netinet/ip.h>
  41 #include <netinet/ip_var.h>
  42
  43 #include <stdio.h>
  44 #include <pcap.h>
  45
  46 #ifdef INET6
  47 #include <netinet/ip6.h>
  48 #endif
  49
  50 #include "interface.h"
  51 #include "addrtoname.h"
  52 #include "ethertype.h"
  53
  54 #include "ether.h"
  55
  56 const u_char *packetp;
  57 const u_char *snapend;
  58
  59 static inline void
  60 ether_print(register const u_char *bp, u_int length)
  61 {
  62         register const struct ether_header *ep;
  63
  64         ep = (const struct ether_header *)bp;
  65         if (qflag)
  66                 (void)printf("%s %s %d: ",
  67                              etheraddr_string(ESRC(ep)),
  68                              etheraddr_string(EDST(ep)),
  69                              length);
  70         else
  71                 (void)printf("%s %s %s %d: ",
  72                              etheraddr_string(ESRC(ep)),
  73                              etheraddr_string(EDST(ep)),
  74                              etherproto_string(ep->ether_type),
  75                              length);
  76 }
  77
  78 static u_short extracted_ethertype;
  79
  80 /*
  81  * This is the top level routine of the printer.  'p' is the points
  82  * to the ether header of the packet, 'h->tv' is the timestamp,
  83  * 'h->length' is the length of the packet off the wire, and 'h->caplen'
  84  * is the number of bytes actually captured.
  85  */
  86 void
  87 ether_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
  88 {
  89         u_int caplen = h->caplen;
  90         u_int length = h->len;
  91         struct ether_header *ep;
  92         u_short ether_type;
  93
  94         ts_print(&h->ts);
  95
  96         if (caplen < sizeof(struct ether_header)) {
  97                 printf("[|ether]");
  98                 goto out;
  99         }
 100
 101         if (eflag)
 102                 ether_print(p, length);
 103
 104         /*
 105          * Some printers want to get back at the ethernet addresses,
 106          * and/or check that they're not walking off the end of the packet.
 107          * Rather than pass them all the way down, we set these globals.
 108          */
 109         packetp = p;
 110         snapend = p + caplen;
 111
 112         length -= sizeof(struct ether_header);
 113         caplen -= sizeof(struct ether_header);
 114         ep = (struct ether_header *)p;
 115         p += sizeof(struct ether_header);
 116
 117         ether_type = ntohs(ep->ether_type);
 118
 119         /*
 120          * Is it (gag) an 802.3 encapsulation?
 121          */
 122         extracted_ethertype = 0;
 123         if (ether_type <= ETHERMTU) {
 124                 /* Try to print the LLC-layer header & higher layers */
 125                 if (llc_print(p, length, caplen, ESRC(ep), EDST(ep)) == 0) {
 126                         /* ether_type not known, print raw packet */
 127                         if (!eflag)
 128                                 ether_print((u_char *)ep, length);
 129                         if (extracted_ethertype) {
 130                                 printf("(LLC %s) ",
 131                                etherproto_string(htons(extracted_ethertype)));
 132                         }
 133                         if (!xflag && !qflag)
 134                                 default_print(p, caplen);
 135                 }
 136         } else if (ether_encap_print(ether_type, p, length, caplen) == 0) {
 137                 /* ether_type not known, print raw packet */
 138                 if (!eflag)
 139                         ether_print((u_char *)ep, length + sizeof(*ep));
 140                 if (!xflag && !qflag)
 141                         default_print(p, caplen);
 142         }
 143         if (xflag)
 144                 default_print(p, caplen);
 145  out:
 146         putchar('\n');
 147 }
 148
 149 /*
 150  * Prints the packet encapsulated in an Ethernet data segment
 151  * (or an equivalent encapsulation), given the Ethernet type code.
 152  *
 153  * Returns non-zero if it can do so, zero if the ethertype is unknown.
 154  *
 155  * Stuffs the ether type into a global for the benefit of lower layers
 156  * that might want to know what it is.
 157  */
 158
 159 int
 160 ether_encap_print(u_short ethertype, const u_char *p,
 161     u_int length, u_int caplen)
 162 {
 163  recurse:
 164         extracted_ethertype = ethertype;
 165
 166         switch (ethertype) {
 167
 168         case ETHERTYPE_IP:
 169                 ip_print(p, length);
 170                 return (1);
 171
 172 #ifdef INET6
 173         case ETHERTYPE_IPV6:
 174                 ip6_print(p, length);
 175                 return (1);
 176 #endif /*INET6*/
 177
 178         case ETHERTYPE_ARP:
 179         case ETHERTYPE_REVARP:
 180                 arp_print(p, length, caplen);
 181                 return (1);
 182
 183         case ETHERTYPE_DN:
 184                 decnet_print(p, length, caplen);
 185                 return (1);
 186
 187         case ETHERTYPE_ATALK:
 188                 if (vflag)
 189                         fputs("et1 ", stdout);
 190                 atalk_print(p, length);
 191                 return (1);
 192
 193         case ETHERTYPE_AARP:
 194                 aarp_print(p, length);
 195                 return (1);
 196
 197         case ETHERTYPE_IPX:
 198                 ipx_print(p, length);
 199                 return (1);
 200
 201         case ETHERTYPE_8021Q:
 202                 printf("802.1Q vlan#%d P%d%s",
 203                        ntohs(*(u_int16_t *)p) & 0xfff,
 204                        ntohs(*(u_int16_t *)p) >> 13,
 205                        (ntohs(*(u_int16_t *)p) & 0x1000) ? " CFI" : "");
 206                 ethertype = ntohs(*(u_int16_t *)(p + 2));
 207                 p += 4;
 208                 length -= 4;
 209                 caplen -= 4;
 210                 if (ethertype > ETHERMTU)
 211                         goto recurse;
 212
 213                 extracted_ethertype = 0;
 214
 215                 if (llc_print(p, length, caplen, p - 18, p - 12) == 0) {
 216                         /* ether_type not known, print raw packet */
 217                         if (!eflag)
 218                                 ether_print(p - 18, length + 4);
 219                         if (extracted_ethertype) {
 220                                 printf("(LLC %s) ",
 221                                etherproto_string(htons(extracted_ethertype)));
 222                         }
 223                         if (!xflag && !qflag)
 224                                 default_print(p - 18, caplen + 4);
 225                 }
 226                 return (1);
 227
 228         case ETHERTYPE_PPPOED:
 229         case ETHERTYPE_PPPOES:
 230                 pppoe_print(p, length);
 231                 return (1);
 232
 233         case ETHERTYPE_LAT:
 234         case ETHERTYPE_SCA:
 235         case ETHERTYPE_MOPRC:
 236         case ETHERTYPE_MOPDL:
 237                 /* default_print for now */
 238         default:
 239                 return (0);
 240         }
 241 }