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

   1 /*
   2  * Copyright (c) 1990, 1991, 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
  22 #ifdef HAVE_CONFIG_H
  23 #include "config.h"
  24 #endif
  25
  26 #include <tcpdump-stdinc.h>
  27
  28 #include <pcap.h>
  29 #include <stdio.h>
  30
  31 #include "interface.h"
  32 #include "addrtoname.h"
  33 #include "ethertype.h"
  34 #include "extract.h"
  35 #include "ppp.h"
  36 #include "chdlc.h"
  37
  38 static void chdlc_slarp_print(const u_char *, u_int);
  39
  40 static const struct tok chdlc_cast_values[] = {
  41     { CHDLC_UNICAST, "unicast" },
  42     { CHDLC_BCAST, "bcast" },
  43     { 0, NULL}
  44 };
  45
  46
  47 /* Standard CHDLC printer */
  48 u_int
  49 chdlc_if_print(const struct pcap_pkthdr *h, register const u_char *p)
  50 {
  51         register u_int length = h->len;
  52         register u_int caplen = h->caplen;
  53
  54         if (caplen < CHDLC_HDRLEN) {
  55                 printf("[|chdlc]");
  56                 return (caplen);
  57         }
  58         return (chdlc_print(p,length));
  59 }
  60
  61 u_int
  62 chdlc_print(register const u_char *p, u_int length) {
  63         u_int proto;
  64
  65         proto = EXTRACT_16BITS(&p[2]);
  66         if (eflag) {
  67                 printf("%s, ethertype %s (0x%04x), length %u: ",
  68                        tok2str(chdlc_cast_values, "0x%02x", p[0]),
  69                        tok2str(ethertype_values, "Unknown", proto),
  70                        proto,
  71                        length);
  72         }
  73
  74         length -= CHDLC_HDRLEN;
  75         p += CHDLC_HDRLEN;
  76
  77         switch (proto) {
  78         case ETHERTYPE_IP:
  79                 ip_print(gndo, p, length);
  80                 break;
  81 #ifdef INET6
  82         case ETHERTYPE_IPV6:
  83                 ip6_print(gndo, p, length);
  84                 break;
  85 #endif
  86         case CHDLC_TYPE_SLARP:
  87                 chdlc_slarp_print(p, length);
  88                 break;
  89 #if 0
  90         case CHDLC_TYPE_CDP:
  91                 chdlc_cdp_print(p, length);
  92                 break;
  93 #endif
  94         case ETHERTYPE_MPLS:
  95         case ETHERTYPE_MPLS_MULTI:
  96                 mpls_print(p, length);
  97                 break;
  98         case ETHERTYPE_ISO:
  99                 /* is the fudge byte set ? lets verify by spotting ISO headers */
 100                 if (*(p+1) == 0x81 ||
 101                     *(p+1) == 0x82 ||
 102                     *(p+1) == 0x83)
 103                     isoclns_print(p+1, length-1, length-1);
 104                 else
 105                     isoclns_print(p, length, length);
 106                 break;
 107         default:
 108                 if (!eflag)
 109                         printf("unknown CHDLC protocol (0x%04x)", proto);
 110                 break;
 111         }
 112
 113         return (CHDLC_HDRLEN);
 114 }
 115
 116 /*
 117  * The fixed-length portion of a SLARP packet.
 118  */
 119 struct cisco_slarp {
 120         u_int8_t code[4];
 121 #define SLARP_REQUEST   0
 122 #define SLARP_REPLY     1
 123 #define SLARP_KEEPALIVE 2
 124         union {
 125                 struct {
 126                         u_int8_t addr[4];
 127                         u_int8_t mask[4];
 128                 } addr;
 129                 struct {
 130                         u_int8_t myseq[4];
 131                         u_int8_t yourseq[4];
 132                         u_int8_t rel[2];
 133                 } keep;
 134         } un;
 135 };
 136
 137 #define SLARP_MIN_LEN   14
 138 #define SLARP_MAX_LEN   18
 139
 140 static void
 141 chdlc_slarp_print(const u_char *cp, u_int length)
 142 {
 143         const struct cisco_slarp *slarp;
 144         u_int sec,min,hrs,days;
 145
 146         printf("SLARP (length: %u), ",length);
 147         if (length < SLARP_MIN_LEN)
 148                 goto trunc;
 149
 150         slarp = (const struct cisco_slarp *)cp;
 151         TCHECK2(*slarp, SLARP_MIN_LEN);
 152         switch (EXTRACT_32BITS(&slarp->code)) {
 153         case SLARP_REQUEST:
 154                 printf("request");
 155                 /*
 156                  * At least according to William "Chops" Westfield's
 157                  * message in
 158                  *
 159                  *      http://www.nethelp.no/net/cisco-hdlc.txt
 160                  *
 161                  * the address and mask aren't used in requests -
 162                  * they're just zero.
 163                  */
 164                 break;
 165         case SLARP_REPLY:
 166                 printf("reply %s/%s",
 167                         ipaddr_string(&slarp->un.addr.addr),
 168                         ipaddr_string(&slarp->un.addr.mask));
 169                 break;
 170         case SLARP_KEEPALIVE:
 171                 printf("keepalive: mineseen=0x%08x, yourseen=0x%08x, reliability=0x%04x",
 172                        EXTRACT_32BITS(&slarp->un.keep.myseq),
 173                        EXTRACT_32BITS(&slarp->un.keep.yourseq),
 174                        EXTRACT_16BITS(&slarp->un.keep.rel));
 175
 176                 if (length >= SLARP_MAX_LEN) { /* uptime-stamp is optional */
 177                         cp += SLARP_MIN_LEN;
 178                         if (!TTEST2(*cp, 4))
 179                                 goto trunc;
 180                         sec = EXTRACT_32BITS(cp) / 1000;
 181                         min = sec / 60; sec -= min * 60;
 182                         hrs = min / 60; min -= hrs * 60;
 183                         days = hrs / 24; hrs -= days * 24;
 184                         printf(", link uptime=%ud%uh%um%us",days,hrs,min,sec);
 185                 }
 186                 break;
 187         default:
 188                 printf("0x%02x unknown", EXTRACT_32BITS(&slarp->code));
 189                 if (vflag <= 1)
 190                     print_unknown_data(gndo,cp+4,"\n\t",length-4);
 191                 break;
 192         }
 193
 194         if (SLARP_MAX_LEN < length && vflag)
 195                 printf(", (trailing junk: %d bytes)", length - SLARP_MAX_LEN);
 196         if (vflag > 1)
 197             print_unknown_data(gndo,cp+4,"\n\t",length-4);
 198         return;
 199
 200 trunc:
 201         printf("[|slarp]");
 202 }
 203
 204
 205 /*
 206  * Local Variables:
 207  * c-style: whitesmith
 208  * c-basic-offset: 8
 209  * End:
 210  */