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 1.44 1999-10-07 23:47:11 mcr Exp $ (LBL)";
  24 #endif
  25
  26 #include <sys/param.h>
  27 #include <sys/time.h>
  28 #include <sys/socket.h>
  29
  30 #if __STDC__
  31 struct mbuf;
  32 struct rtentry;
  33 #endif
  34 #include <net/if.h>
  35
  36 #include <netinet/in.h>
  37 #include <netinet/if_ether.h>
  38 #include <netinet/in_systm.h>
  39 #include <netinet/ip.h>
  40 #include <netinet/ip_var.h>
  41 #include <netinet/udp.h>
  42 #include <netinet/udp_var.h>
  43 #include <netinet/tcp.h>
  44 #include <netinet/tcpip.h>
  45
  46 #include <stdio.h>
  47 #include <pcap.h>
  48
  49 #include "interface.h"
  50 #include "addrtoname.h"
  51 #include "ethertype.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 /*
  76  * This is the top level routine of the printer.  'p' is the points
  77  * to the ether header of the packet, 'tvp' is the timestamp,
  78  * 'length' is the length of the packet off the wire, and 'caplen'
  79  * is the number of bytes actually captured.
  80  */
  81 void
  82 ether_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
  83 {
  84         u_int caplen = h->caplen;
  85         u_int length = h->len;
  86         struct ether_header *ep;
  87         u_short ether_type;
  88         extern u_short extracted_ethertype;
  89
  90         ts_print(&h->ts);
  91
  92         if (caplen < sizeof(struct ether_header)) {
  93                 printf("[|ether]");
  94                 goto out;
  95         }
  96
  97         if (eflag)
  98                 ether_print(p, length);
  99
 100         /*
 101          * Some printers want to get back at the ethernet addresses,
 102          * and/or check that they're not walking off the end of the packet.
 103          * Rather than pass them all the way down, we set these globals.
 104          */
 105         packetp = p;
 106         snapend = p + caplen;
 107
 108         length -= sizeof(struct ether_header);
 109         caplen -= sizeof(struct ether_header);
 110         ep = (struct ether_header *)p;
 111         p += sizeof(struct ether_header);
 112
 113         ether_type = ntohs(ep->ether_type);
 114
 115         /*
 116          * Is it (gag) an 802.3 encapsulation?
 117          */
 118         extracted_ethertype = 0;
 119         if (ether_type <= ETHERMTU) {
 120                 /* Try to print the LLC-layer header & higher layers */
 121                 if (llc_print(p, length, caplen, ESRC(ep), EDST(ep)) == 0) {
 122                         /* ether_type not known, print raw packet */
 123                         if (!eflag)
 124                                 ether_print((u_char *)ep, length);
 125                         if (extracted_ethertype) {
 126                                 printf("(LLC %s) ",
 127                                etherproto_string(htons(extracted_ethertype)));
 128                         }
 129                         if (!xflag && !qflag)
 130                                 default_print(p, caplen);
 131                 }
 132         } else if (ether_encap_print(ether_type, p, length, caplen) == 0) {
 133                 /* ether_type not known, print raw packet */
 134                 if (!eflag)
 135                         ether_print((u_char *)ep, length + sizeof(*ep));
 136                 if (!xflag && !qflag)
 137                         default_print(p, caplen);
 138         }
 139         if (xflag)
 140                 default_print(p, caplen);
 141  out:
 142         putchar('\n');
 143 }
 144
 145 /*
 146  * Prints the packet encapsulated in an Ethernet data segment
 147  * (or an equivalent encapsulation), given the Ethernet type code.
 148  *
 149  * Returns non-zero if it can do so, zero if the ethertype is unknown.
 150  *
 151  * Stuffs the ether type into a global for the benefit of lower layers
 152  * that might want to know what it is.
 153  */
 154
 155 u_short extracted_ethertype;
 156
 157 int
 158 ether_encap_print(u_short ethertype, const u_char *p,
 159     u_int length, u_int caplen)
 160 {
 161         extracted_ethertype = ethertype;
 162
 163         switch (ethertype) {
 164
 165         case ETHERTYPE_IP:
 166                 ip_print(p, length);
 167                 return (1);
 168
 169         case ETHERTYPE_ARP:
 170         case ETHERTYPE_REVARP:
 171                 arp_print(p, length, caplen);
 172                 return (1);
 173
 174         case ETHERTYPE_DN:
 175                 decnet_print(p, length, caplen);
 176                 return (1);
 177
 178         case ETHERTYPE_ATALK:
 179                 if (vflag)
 180                         fputs("et1 ", stdout);
 181                 atalk_print(p, length);
 182                 return (1);
 183
 184         case ETHERTYPE_AARP:
 185                 aarp_print(p, length);
 186                 return (1);
 187
 188         case ETHERTYPE_LAT:
 189         case ETHERTYPE_SCA:
 190         case ETHERTYPE_MOPRC:
 191         case ETHERTYPE_MOPDL:
 192                 /* default_print for now */
 193         default:
 194                 return (0);
 195         }
 196 }