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 #define NETDISSECT_REWORKED
  23 #ifdef HAVE_CONFIG_H
  24 #include "config.h"
  25 #endif
  26
  27 #include <tcpdump-stdinc.h>
  28
  29 #include "interface.h"
  30 #include "addrtoname.h"
  31 #include "ethertype.h"
  32 #include "extract.h"
  33 #include "chdlc.h"
  34
  35 static void chdlc_slarp_print(netdissect_options *, const u_char *, u_int);
  36
  37 static const struct tok chdlc_cast_values[] = {
  38     { CHDLC_UNICAST, "unicast" },
  39     { CHDLC_BCAST, "bcast" },
  40     { 0, NULL}
  41 };
  42
  43
  44 /* Standard CHDLC printer */
  45 u_int
  46 chdlc_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, register const u_char *p)
  47 {
  48         register u_int length = h->len;
  49         register u_int caplen = h->caplen;
  50
  51         if (caplen < CHDLC_HDRLEN) {
  52                 ND_PRINT((ndo, "[|chdlc]"));
  53                 return (caplen);
  54         }
  55         return (chdlc_print(ndo, p,length));
  56 }
  57
  58 u_int
  59 chdlc_print(netdissect_options *ndo, register const u_char *p, u_int length) {
  60         u_int proto;
  61
  62         proto = EXTRACT_16BITS(&p[2]);
  63         if (ndo->ndo_eflag) {
  64                 ND_PRINT((ndo, "%s, ethertype %s (0x%04x), length %u: ",
  65                        tok2str(chdlc_cast_values, "0x%02x", p[0]),
  66                        tok2str(ethertype_values, "Unknown", proto),
  67                        proto,
  68                        length));
  69         }
  70
  71         length -= CHDLC_HDRLEN;
  72         p += CHDLC_HDRLEN;
  73
  74         switch (proto) {
  75         case ETHERTYPE_IP:
  76                 ip_print(ndo, p, length);
  77                 break;
  78 #ifdef INET6
  79         case ETHERTYPE_IPV6:
  80                 ip6_print(ndo, p, length);
  81                 break;
  82 #endif
  83         case CHDLC_TYPE_SLARP:
  84                 chdlc_slarp_print(ndo, p, length);
  85                 break;
  86 #if 0
  87         case CHDLC_TYPE_CDP:
  88                 chdlc_cdp_print(p, length);
  89                 break;
  90 #endif
  91         case ETHERTYPE_MPLS:
  92         case ETHERTYPE_MPLS_MULTI:
  93                 mpls_print(ndo, p, length);
  94                 break;
  95         case ETHERTYPE_ISO:
  96                 /* is the fudge byte set ? lets verify by spotting ISO headers */
  97                 if (*(p+1) == 0x81 ||
  98                     *(p+1) == 0x82 ||
  99                     *(p+1) == 0x83)
 100                     isoclns_print(ndo, p + 1, length - 1, length - 1);
 101                 else
 102                     isoclns_print(ndo, p, length, length);
 103                 break;
 104         default:
 105                 if (!ndo->ndo_eflag)
 106                         ND_PRINT((ndo, "unknown CHDLC protocol (0x%04x)", proto));
 107                 break;
 108         }
 109
 110         return (CHDLC_HDRLEN);
 111 }
 112
 113 /*
 114  * The fixed-length portion of a SLARP packet.
 115  */
 116 struct cisco_slarp {
 117         uint8_t code[4];
 118 #define SLARP_REQUEST   0
 119 #define SLARP_REPLY     1
 120 #define SLARP_KEEPALIVE 2
 121         union {
 122                 struct {
 123                         uint8_t addr[4];
 124                         uint8_t mask[4];
 125                 } addr;
 126                 struct {
 127                         uint8_t myseq[4];
 128                         uint8_t yourseq[4];
 129                         uint8_t rel[2];
 130                 } keep;
 131         } un;
 132 };
 133
 134 #define SLARP_MIN_LEN   14
 135 #define SLARP_MAX_LEN   18
 136
 137 static void
 138 chdlc_slarp_print(netdissect_options *ndo, const u_char *cp, u_int length)
 139 {
 140         const struct cisco_slarp *slarp;
 141         u_int sec,min,hrs,days;
 142
 143         ND_PRINT((ndo, "SLARP (length: %u), ",length));
 144         if (length < SLARP_MIN_LEN)
 145                 goto trunc;
 146
 147         slarp = (const struct cisco_slarp *)cp;
 148         ND_TCHECK2(*slarp, SLARP_MIN_LEN);
 149         switch (EXTRACT_32BITS(&slarp->code)) {
 150         case SLARP_REQUEST:
 151                 ND_PRINT((ndo, "request"));
 152                 /*
 153                  * At least according to William "Chops" Westfield's
 154                  * message in
 155                  *
 156                  *      http://www.nethelp.no/net/cisco-hdlc.txt
 157                  *
 158                  * the address and mask aren't used in requests -
 159                  * they're just zero.
 160                  */
 161                 break;
 162         case SLARP_REPLY:
 163                 ND_PRINT((ndo, "reply %s/%s",
 164                         ipaddr_string(ndo, &slarp->un.addr.addr),
 165                         ipaddr_string(ndo, &slarp->un.addr.mask)));
 166                 break;
 167         case SLARP_KEEPALIVE:
 168                 ND_PRINT((ndo, "keepalive: mineseen=0x%08x, yourseen=0x%08x, reliability=0x%04x",
 169                        EXTRACT_32BITS(&slarp->un.keep.myseq),
 170                        EXTRACT_32BITS(&slarp->un.keep.yourseq),
 171                        EXTRACT_16BITS(&slarp->un.keep.rel)));
 172
 173                 if (length >= SLARP_MAX_LEN) { /* uptime-stamp is optional */
 174                         cp += SLARP_MIN_LEN;
 175                         ND_TCHECK2(*cp, 4);
 176                         sec = EXTRACT_32BITS(cp) / 1000;
 177                         min = sec / 60; sec -= min * 60;
 178                         hrs = min / 60; min -= hrs * 60;
 179                         days = hrs / 24; hrs -= days * 24;
 180                         ND_PRINT((ndo, ", link uptime=%ud%uh%um%us",days,hrs,min,sec));
 181                 }
 182                 break;
 183         default:
 184                 ND_PRINT((ndo, "0x%02x unknown", EXTRACT_32BITS(&slarp->code)));
 185                 if (ndo->ndo_vflag <= 1)
 186                     print_unknown_data(ndo,cp+4,"\n\t",length-4);
 187                 break;
 188         }
 189
 190         if (SLARP_MAX_LEN < length && ndo->ndo_vflag)
 191                 ND_PRINT((ndo, ", (trailing junk: %d bytes)", length - SLARP_MAX_LEN));
 192         if (ndo->ndo_vflag > 1)
 193             print_unknown_data(ndo,cp+4,"\n\t",length-4);
 194         return;
 195
 196 trunc:
 197         ND_PRINT((ndo, "[|slarp]"));
 198 }
 199
 200
 201 /*
 202  * Local Variables:
 203  * c-style: whitesmith
 204  * c-basic-offset: 8
 205  * End:
 206  */