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