The Tcpdump Group git mirrors - tcpdump/blob - print-ether.c

   1 /*
   2  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000
   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 1.69 2002-06-01 23:50:31 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 #include <netinet/in.h>
  35
  36 #include <stdio.h>
  37 #include <pcap.h>
  38
  39 #include "interface.h"
  40 #include "addrtoname.h"
  41 #include "ethertype.h"
  42
  43 #include "ether.h"
  44
  45 const u_char *packetp;
  46 const u_char *snapend;
  47
  48 static inline void
  49 ether_hdr_print(register const u_char *bp, u_int length)
  50 {
  51         register const struct ether_header *ep;
  52
  53         ep = (const struct ether_header *)bp;
  54         if (qflag)
  55                 (void)printf("%s %s %d: ",
  56                              etheraddr_string(ESRC(ep)),
  57                              etheraddr_string(EDST(ep)),
  58                              length);
  59         else
  60                 (void)printf("%s %s %s %d: ",
  61                              etheraddr_string(ESRC(ep)),
  62                              etheraddr_string(EDST(ep)),
  63                              etherproto_string(ep->ether_type),
  64                              length);
  65 }
  66
  67 void
  68 ether_print(const u_char *p, u_int length, u_int caplen)
  69 {
  70         struct ether_header *ep;
  71         u_short ether_type;
  72         u_short extracted_ethertype;
  73
  74         if (caplen < ETHER_HDRLEN) {
  75                 printf("[|ether]");
  76                 return;
  77         }
  78
  79         if (eflag)
  80                 ether_hdr_print(p, length);
  81
  82         /*
  83          * Some printers want to get back at the ethernet addresses,
  84          * and/or check that they're not walking off the end of the packet.
  85          * Rather than pass them all the way down, we set these globals.
  86          */
  87         packetp = p;
  88         snapend = p + caplen;
  89
  90         length -= ETHER_HDRLEN;
  91         caplen -= ETHER_HDRLEN;
  92         ep = (struct ether_header *)p;
  93         p += ETHER_HDRLEN;
  94
  95         ether_type = ntohs(ep->ether_type);
  96
  97         /*
  98          * Is it (gag) an 802.3 encapsulation?
  99          */
 100         extracted_ethertype = 0;
 101         if (ether_type <= ETHERMTU) {
 102                 /* Try to print the LLC-layer header & higher layers */
 103                 if (llc_print(p, length, caplen, ESRC(ep), EDST(ep),
 104                     &extracted_ethertype) == 0) {
 105                         /* ether_type not known, print raw packet */
 106                         if (!eflag)
 107                                 ether_hdr_print((u_char *)ep, length + ETHER_HDRLEN);
 108                         if (extracted_ethertype) {
 109                                 printf("(LLC %s) ",
 110                                etherproto_string(htons(extracted_ethertype)));
 111                         }
 112                         if (!xflag && !qflag)
 113                                 default_print(p, caplen);
 114                 }
 115         } else if (ether_encap_print(ether_type, p, length, caplen,
 116             &extracted_ethertype) == 0) {
 117                 /* ether_type not known, print raw packet */
 118                 if (!eflag)
 119                         ether_hdr_print((u_char *)ep, length + ETHER_HDRLEN);
 120                 if (!xflag && !qflag)
 121                         default_print(p, caplen);
 122         }
 123 }
 124
 125 /*
 126  * This is the top level routine of the printer.  'p' is the points
 127  * to the ether header of the packet, 'h->tv' is the timestamp,
 128  * 'h->length' is the length of the packet off the wire, and 'h->caplen'
 129  * is the number of bytes actually captured.
 130  */
 131 void
 132 ether_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
 133 {
 134         u_int caplen = h->caplen;
 135         u_int length = h->len;
 136
 137         ++infodelay;
 138         ts_print(&h->ts);
 139
 140         ether_print(p, length, caplen);
 141
 142         /*
 143          * If "-x" was specified, print stuff past the Ethernet header,
 144          * if there's anything to print.
 145          */
 146         if (xflag && caplen > ETHER_HDRLEN)
 147                 default_print(p + ETHER_HDRLEN, caplen - ETHER_HDRLEN);
 148
 149         putchar('\n');
 150
 151         --infodelay;
 152         if (infoprint)
 153                 info(0);
 154 }
 155
 156 /*
 157  * Prints the packet encapsulated in an Ethernet data segment
 158  * (or an equivalent encapsulation), given the Ethernet type code.
 159  *
 160  * Returns non-zero if it can do so, zero if the ethertype is unknown.
 161  *
 162  * The Ethernet type code is passed through a pointer; if it was
 163  * ETHERTYPE_8021Q, it gets updated to be the Ethernet type of
 164  * the 802.1Q payload, for the benefit of lower layers that might
 165  * want to know what it is.
 166  */
 167
 168 int
 169 ether_encap_print(u_short ethertype, const u_char *p,
 170     u_int length, u_int caplen, u_short *extracted_ethertype)
 171 {
 172  recurse:
 173         *extracted_ethertype = ethertype;
 174
 175         switch (ethertype) {
 176
 177         case ETHERTYPE_IP:
 178                 ip_print(p, length);
 179                 return (1);
 180
 181 #ifdef INET6
 182         case ETHERTYPE_IPV6:
 183                 ip6_print(p, length);
 184                 return (1);
 185 #endif /*INET6*/
 186
 187         case ETHERTYPE_ARP:
 188         case ETHERTYPE_REVARP:
 189                 arp_print(p, length, caplen);
 190                 return (1);
 191
 192         case ETHERTYPE_DN:
 193                 decnet_print(p, length, caplen);
 194                 return (1);
 195
 196         case ETHERTYPE_ATALK:
 197                 if (vflag)
 198                         fputs("et1 ", stdout);
 199                 atalk_print(p, length);
 200                 return (1);
 201
 202         case ETHERTYPE_AARP:
 203                 aarp_print(p, length);
 204                 return (1);
 205
 206         case ETHERTYPE_IPX:
 207                 printf("(NOV-ETHII) ");
 208                 ipx_print(p, length);
 209                 return (1);
 210
 211         case ETHERTYPE_8021Q:
 212                 printf("802.1Q vlan#%d P%d%s ",
 213                        ntohs(*(u_int16_t *)p) & 0xfff,
 214                        ntohs(*(u_int16_t *)p) >> 13,
 215                        (ntohs(*(u_int16_t *)p) & 0x1000) ? " CFI" : "");
 216                 ethertype = ntohs(*(u_int16_t *)(p + 2));
 217                 p += 4;
 218                 length -= 4;
 219                 caplen -= 4;
 220                 if (ethertype > ETHERMTU)
 221                         goto recurse;
 222
 223                 *extracted_ethertype = 0;
 224
 225                 if (llc_print(p, length, caplen, p - 18, p - 12,
 226                     extracted_ethertype) == 0) {
 227                         /* ether_type not known, print raw packet */
 228                         if (!eflag)
 229                                 ether_hdr_print(p - 18, length + 4);
 230                         if (*extracted_ethertype) {
 231                                 printf("(LLC %s) ",
 232                                etherproto_string(htons(*extracted_ethertype)));
 233                         }
 234                         if (!xflag && !qflag)
 235                                 default_print(p - 18, caplen + 4);
 236                 }
 237                 return (1);
 238
 239         case ETHERTYPE_PPPOED:
 240         case ETHERTYPE_PPPOES:
 241                 pppoe_print(p, length);
 242                 return (1);
 243
 244         case ETHERTYPE_PPP:
 245                 printf("ppp");
 246                 if (length) {
 247                         printf(": ");
 248                         ppp_print(p, length);
 249                 }
 250                 return (1);
 251
 252         case ETHERTYPE_MPLS:
 253         case ETHERTYPE_MPLS_MULTI:
 254                 mpls_print(p, length);
 255                 return (1);
 256
 257         case ETHERTYPE_LAT:
 258         case ETHERTYPE_SCA:
 259         case ETHERTYPE_MOPRC:
 260         case ETHERTYPE_MOPDL:
 261                 /* default_print for now */
 262         default:
 263                 return (0);
 264         }
 265 }