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 1.49 2000-04-28 11:38:38 itojun 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 #if __STDC__
  35 struct mbuf;
  36 struct rtentry;
  37 #endif
  38 #include <net/if.h>
  39
  40 #include <netinet/in.h>
  41 #include <netinet/if_ether.h>
  42 #include <netinet/in_systm.h>
  43 #include <netinet/ip.h>
  44 #include <netinet/ip_var.h>
  45 #include <netinet/udp.h>
  46 #include <netinet/udp_var.h>
  47 #include <netinet/tcp.h>
  48
  49 #include <stdio.h>
  50 #include <pcap.h>
  51
  52 #ifdef INET6
  53 #include <netinet/ip6.h>
  54 #endif
  55
  56 #include "interface.h"
  57 #include "addrtoname.h"
  58 #include "ethertype.h"
  59
  60 const u_char *packetp;
  61 const u_char *snapend;
  62
  63 static inline void
  64 ether_print(register const u_char *bp, u_int length)
  65 {
  66         register const struct ether_header *ep;
  67
  68         ep = (const struct ether_header *)bp;
  69         if (qflag)
  70                 (void)printf("%s %s %d: ",
  71                              etheraddr_string(ESRC(ep)),
  72                              etheraddr_string(EDST(ep)),
  73                              length);
  74         else
  75                 (void)printf("%s %s %s %d: ",
  76                              etheraddr_string(ESRC(ep)),
  77                              etheraddr_string(EDST(ep)),
  78                              etherproto_string(ep->ether_type),
  79                              length);
  80 }
  81
  82 static u_short extracted_ethertype;
  83
  84 /*
  85  * This is the top level routine of the printer.  'p' is the points
  86  * to the ether header of the packet, 'h->tv' is the timestamp,
  87  * 'h->length' is the length of the packet off the wire, and 'h->caplen'
  88  * is the number of bytes actually captured.
  89  */
  90 void
  91 ether_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
  92 {
  93         u_int caplen = h->caplen;
  94         u_int length = h->len;
  95         struct ether_header *ep;
  96         u_short ether_type;
  97
  98         ts_print(&h->ts);
  99
 100         if (caplen < sizeof(struct ether_header)) {
 101                 printf("[|ether]");
 102                 goto out;
 103         }
 104
 105         if (eflag)
 106                 ether_print(p, length);
 107
 108         /*
 109          * Some printers want to get back at the ethernet addresses,
 110          * and/or check that they're not walking off the end of the packet.
 111          * Rather than pass them all the way down, we set these globals.
 112          */
 113         packetp = p;
 114         snapend = p + caplen;
 115
 116         length -= sizeof(struct ether_header);
 117         caplen -= sizeof(struct ether_header);
 118         ep = (struct ether_header *)p;
 119         p += sizeof(struct ether_header);
 120
 121         ether_type = ntohs(ep->ether_type);
 122
 123         /*
 124          * Is it (gag) an 802.3 encapsulation?
 125          */
 126         extracted_ethertype = 0;
 127         if (ether_type <= ETHERMTU) {
 128                 /* Try to print the LLC-layer header & higher layers */
 129                 if (llc_print(p, length, caplen, ESRC(ep), EDST(ep)) == 0) {
 130                         /* ether_type not known, print raw packet */
 131                         if (!eflag)
 132                                 ether_print((u_char *)ep, length);
 133                         if (extracted_ethertype) {
 134                                 printf("(LLC %s) ",
 135                                etherproto_string(htons(extracted_ethertype)));
 136                         }
 137                         if (!xflag && !qflag)
 138                                 default_print(p, caplen);
 139                 }
 140         } else if (ether_encap_print(ether_type, p, length, caplen) == 0) {
 141                 /* ether_type not known, print raw packet */
 142                 if (!eflag)
 143                         ether_print((u_char *)ep, length + sizeof(*ep));
 144                 if (!xflag && !qflag)
 145                         default_print(p, caplen);
 146         }
 147         if (xflag)
 148                 default_print(p, caplen);
 149  out:
 150         putchar('\n');
 151 }
 152
 153 /*
 154  * Prints the packet encapsulated in an Ethernet data segment
 155  * (or an equivalent encapsulation), given the Ethernet type code.
 156  *
 157  * Returns non-zero if it can do so, zero if the ethertype is unknown.
 158  *
 159  * Stuffs the ether type into a global for the benefit of lower layers
 160  * that might want to know what it is.
 161  */
 162
 163 int
 164 ether_encap_print(u_short ethertype, const u_char *p,
 165     u_int length, u_int caplen)
 166 {
 167  recurse:
 168         extracted_ethertype = ethertype;
 169
 170         switch (ethertype) {
 171
 172         case ETHERTYPE_IP:
 173                 ip_print(p, length);
 174                 return (1);
 175
 176 #ifdef INET6
 177         case ETHERTYPE_IPV6:
 178                 ip6_print(p, length);
 179                 return (1);
 180 #endif /*INET6*/
 181
 182         case ETHERTYPE_ARP:
 183         case ETHERTYPE_REVARP:
 184                 arp_print(p, length, caplen);
 185                 return (1);
 186
 187         case ETHERTYPE_DN:
 188                 decnet_print(p, length, caplen);
 189                 return (1);
 190
 191         case ETHERTYPE_ATALK:
 192                 if (vflag)
 193                         fputs("et1 ", stdout);
 194                 atalk_print(p, length);
 195                 return (1);
 196
 197         case ETHERTYPE_AARP:
 198                 aarp_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 }