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 1.52 2000-09-23 08:03:35 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 #include <netinet/udp.h>
  43 #include <netinet/udp_var.h>
  44 #include <netinet/tcp.h>
  45
  46 #include <stdio.h>
  47 #include <pcap.h>
  48
  49 #ifdef INET6
  50 #include <netinet/ip6.h>
  51 #endif
  52
  53 #include "interface.h"
  54 #include "addrtoname.h"
  55 #include "ethertype.h"
  56
  57 #include "ether.h"
  58
  59 const u_char *packetp;
  60 const u_char *snapend;
  61
  62 static inline void
  63 ether_print(register const u_char *bp, u_int length)
  64 {
  65         register const struct ether_header *ep;
  66
  67         ep = (const struct ether_header *)bp;
  68         if (qflag)
  69                 (void)printf("%s %s %d: ",
  70                              etheraddr_string(ESRC(ep)),
  71                              etheraddr_string(EDST(ep)),
  72                              length);
  73         else
  74                 (void)printf("%s %s %s %d: ",
  75                              etheraddr_string(ESRC(ep)),
  76                              etheraddr_string(EDST(ep)),
  77                              etherproto_string(ep->ether_type),
  78                              length);
  79 }
  80
  81 static u_short extracted_ethertype;
  82
  83 /*
  84  * This is the top level routine of the printer.  'p' is the points
  85  * to the ether header of the packet, 'h->tv' is the timestamp,
  86  * 'h->length' is the length of the packet off the wire, and 'h->caplen'
  87  * is the number of bytes actually captured.
  88  */
  89 void
  90 ether_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
  91 {
  92         u_int caplen = h->caplen;
  93         u_int length = h->len;
  94         struct ether_header *ep;
  95         u_short ether_type;
  96
  97         ts_print(&h->ts);
  98
  99         if (caplen < sizeof(struct ether_header)) {
 100                 printf("[|ether]");
 101                 goto out;
 102         }
 103
 104         if (eflag)
 105                 ether_print(p, length);
 106
 107         /*
 108          * Some printers want to get back at the ethernet addresses,
 109          * and/or check that they're not walking off the end of the packet.
 110          * Rather than pass them all the way down, we set these globals.
 111          */
 112         packetp = p;
 113         snapend = p + caplen;
 114
 115         length -= sizeof(struct ether_header);
 116         caplen -= sizeof(struct ether_header);
 117         ep = (struct ether_header *)p;
 118         p += sizeof(struct ether_header);
 119
 120         ether_type = ntohs(ep->ether_type);
 121
 122         /*
 123          * Is it (gag) an 802.3 encapsulation?
 124          */
 125         extracted_ethertype = 0;
 126         if (ether_type <= ETHERMTU) {
 127                 /* Try to print the LLC-layer header & higher layers */
 128                 if (llc_print(p, length, caplen, ESRC(ep), EDST(ep)) == 0) {
 129                         /* ether_type not known, print raw packet */
 130                         if (!eflag)
 131                                 ether_print((u_char *)ep, length);
 132                         if (extracted_ethertype) {
 133                                 printf("(LLC %s) ",
 134                                etherproto_string(htons(extracted_ethertype)));
 135                         }
 136                         if (!xflag && !qflag)
 137                                 default_print(p, caplen);
 138                 }
 139         } else if (ether_encap_print(ether_type, p, length, caplen) == 0) {
 140                 /* ether_type not known, print raw packet */
 141                 if (!eflag)
 142                         ether_print((u_char *)ep, length + sizeof(*ep));
 143                 if (!xflag && !qflag)
 144                         default_print(p, caplen);
 145         }
 146         if (xflag)
 147                 default_print(p, caplen);
 148  out:
 149         putchar('\n');
 150 }
 151
 152 /*
 153  * Prints the packet encapsulated in an Ethernet data segment
 154  * (or an equivalent encapsulation), given the Ethernet type code.
 155  *
 156  * Returns non-zero if it can do so, zero if the ethertype is unknown.
 157  *
 158  * Stuffs the ether type into a global for the benefit of lower layers
 159  * that might want to know what it is.
 160  */
 161
 162 int
 163 ether_encap_print(u_short ethertype, const u_char *p,
 164     u_int length, u_int caplen)
 165 {
 166  recurse:
 167         extracted_ethertype = ethertype;
 168
 169         switch (ethertype) {
 170
 171         case ETHERTYPE_IP:
 172                 ip_print(p, length);
 173                 return (1);
 174
 175 #ifdef INET6
 176         case ETHERTYPE_IPV6:
 177                 ip6_print(p, length);
 178                 return (1);
 179 #endif /*INET6*/
 180
 181         case ETHERTYPE_ARP:
 182         case ETHERTYPE_REVARP:
 183                 arp_print(p, length, caplen);
 184                 return (1);
 185
 186         case ETHERTYPE_DN:
 187                 decnet_print(p, length, caplen);
 188                 return (1);
 189
 190         case ETHERTYPE_ATALK:
 191                 if (vflag)
 192                         fputs("et1 ", stdout);
 193                 atalk_print(p, length);
 194                 return (1);
 195
 196         case ETHERTYPE_AARP:
 197                 aarp_print(p, length);
 198                 return (1);
 199
 200         case ETHERTYPE_IPX:
 201                 ipx_print(p, length);
 202                 return (1);
 203
 204         case ETHERTYPE_8021Q:
 205                 printf("802.1Q vlan#%d P%d%s",
 206                        ntohs(*(u_int16_t *)p) & 0xfff,
 207                        ntohs(*(u_int16_t *)p) >> 13,
 208                        (ntohs(*(u_int16_t *)p) & 0x1000) ? " CFI" : "");
 209                 ethertype = ntohs(*(u_int16_t *)(p + 2));
 210                 p += 4;
 211                 length -= 4;
 212                 caplen -= 4;
 213                 if (ethertype > ETHERMTU)
 214                         goto recurse;
 215
 216                 extracted_ethertype = 0;
 217
 218                 if (llc_print(p, length, caplen, p - 18, p - 12) == 0) {
 219                         /* ether_type not known, print raw packet */
 220                         if (!eflag)
 221                                 ether_print(p - 18, length + 4);
 222                         if (extracted_ethertype) {
 223                                 printf("(LLC %s) ",
 224                                etherproto_string(htons(extracted_ethertype)));
 225                         }
 226                         if (!xflag && !qflag)
 227                                 default_print(p - 18, caplen + 4);
 228                 }
 229                 return (1);
 230
 231         case ETHERTYPE_PPPOED:
 232         case ETHERTYPE_PPPOES:
 233                 pppoe_print(p, length);
 234                 return (1);
 235
 236         case ETHERTYPE_LAT:
 237         case ETHERTYPE_SCA:
 238         case ETHERTYPE_MOPRC:
 239         case ETHERTYPE_MOPDL:
 240                 /* default_print for now */
 241         default:
 242                 return (0);
 243         }
 244 }