contrib/tcpdump/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 /* \summary: Cisco HDLC printer */
  23
  24 #ifdef HAVE_CONFIG_H
  25 #include "config.h"
  26 #endif
  27
  28 #include <netdissect-stdinc.h>
  29
  30 #include "netdissect.h"
  31 #include "addrtoname.h"
  32 #include "ethertype.h"
  33 #include "extract.h"
  34 #include "chdlc.h"
  35
  36 static void chdlc_slarp_print(netdissect_options *, const u_char *, u_int);
  37
  38 static const struct tok chdlc_cast_values[] = {
  39     { CHDLC_UNICAST, "unicast" },
  40     { CHDLC_BCAST, "bcast" },
  41     { 0, NULL}
  42 };
  43
  44
  45 /* Standard CHDLC printer */
  46 u_int
  47 chdlc_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, register const u_char *p)
  48 {
  49         return chdlc_print(ndo, p, h->len);
  50 }
  51
  52 u_int
  53 chdlc_print(netdissect_options *ndo, register const u_char *p, u_int length)
  54 {
  55         u_int proto;
  56         const u_char *bp = p;
  57
  58         if (length < CHDLC_HDRLEN)
  59                 goto trunc;
  60         ND_TCHECK2(*p, CHDLC_HDRLEN);
  61         proto = EXTRACT_16BITS(&p[2]);
  62         if (ndo->ndo_eflag) {
  63                 ND_PRINT((ndo, "%s, ethertype %s (0x%04x), length %u: ",
  64                        tok2str(chdlc_cast_values, "0x%02x", p[0]),
  65                        tok2str(ethertype_values, "Unknown", proto),
  66                        proto,
  67                        length));
  68         }
  69
  70         length -= CHDLC_HDRLEN;
  71         p += CHDLC_HDRLEN;
  72
  73         switch (proto) {
  74         case ETHERTYPE_IP:
  75                 ip_print(ndo, p, length);
  76                 break;
  77         case ETHERTYPE_IPV6:
  78                 ip6_print(ndo, p, length);
  79                 break;
  80         case CHDLC_TYPE_SLARP:
  81                 chdlc_slarp_print(ndo, p, length);
  82                 break;
  83 #if 0
  84         case CHDLC_TYPE_CDP:
  85                 chdlc_cdp_print(p, length);
  86                 break;
  87 #endif
  88         case ETHERTYPE_MPLS:
  89         case ETHERTYPE_MPLS_MULTI:
  90                 mpls_print(ndo, p, length);
  91                 break;
  92         case ETHERTYPE_ISO:
  93                 /* is the fudge byte set ? lets verify by spotting ISO headers */
  94                 if (length < 2)
  95                     goto trunc;
  96                 ND_TCHECK_16BITS(p);
  97                 if (*(p+1) == 0x81 ||
  98                     *(p+1) == 0x82 ||
  99                     *(p+1) == 0x83)
 100                     isoclns_print(ndo, p + 1, length - 1);
 101                 else
 102                     isoclns_print(ndo, p, 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 trunc:
 113         ND_PRINT((ndo, "[|chdlc]"));
 114         return ndo->ndo_snapend - bp;
 115 }
 116
 117 /*
 118  * The fixed-length portion of a SLARP packet.
 119  */
 120 struct cisco_slarp {
 121         uint8_t code[4];
 122 #define SLARP_REQUEST   0
 123 #define SLARP_REPLY     1
 124 #define SLARP_KEEPALIVE 2
 125         union {
 126                 struct {
 127                         uint8_t addr[4];
 128                         uint8_t mask[4];
 129                 } addr;
 130                 struct {
 131                         uint8_t myseq[4];
 132                         uint8_t yourseq[4];
 133                         uint8_t rel[2];
 134                 } keep;
 135         } un;
 136 };
 137
 138 #define SLARP_MIN_LEN   14
 139 #define SLARP_MAX_LEN   18
 140
 141 static void
 142 chdlc_slarp_print(netdissect_options *ndo, const u_char *cp, u_int length)
 143 {
 144         const struct cisco_slarp *slarp;
 145         u_int sec,min,hrs,days;
 146
 147         ND_PRINT((ndo, "SLARP (length: %u), ",length));
 148         if (length < SLARP_MIN_LEN)
 149                 goto trunc;
 150
 151         slarp = (const struct cisco_slarp *)cp;
 152         ND_TCHECK2(*slarp, SLARP_MIN_LEN);
 153         switch (EXTRACT_32BITS(&slarp->code)) {
 154         case SLARP_REQUEST:
 155                 ND_PRINT((ndo, "request"));
 156                 /*
 157                  * At least according to William "Chops" Westfield's
 158                  * message in
 159                  *
 160                  *      http://www.nethelp.no/net/cisco-hdlc.txt
 161                  *
 162                  * the address and mask aren't used in requests -
 163                  * they're just zero.
 164                  */
 165                 break;
 166         case SLARP_REPLY:
 167                 ND_PRINT((ndo, "reply %s/%s",
 168                         ipaddr_string(ndo, &slarp->un.addr.addr),
 169                         ipaddr_string(ndo, &slarp->un.addr.mask)));
 170                 break;
 171         case SLARP_KEEPALIVE:
 172                 ND_PRINT((ndo, "keepalive: mineseen=0x%08x, yourseen=0x%08x, reliability=0x%04x",
 173                        EXTRACT_32BITS(&slarp->un.keep.myseq),
 174                        EXTRACT_32BITS(&slarp->un.keep.yourseq),
 175                        EXTRACT_16BITS(&slarp->un.keep.rel)));
 176
 177                 if (length >= SLARP_MAX_LEN) { /* uptime-stamp is optional */
 178                         cp += SLARP_MIN_LEN;
 179                         ND_TCHECK2(*cp, 4);
 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                         ND_PRINT((ndo, ", link uptime=%ud%uh%um%us",days,hrs,min,sec));
 185                 }
 186                 break;
 187         default:
 188                 ND_PRINT((ndo, "0x%02x unknown", EXTRACT_32BITS(&slarp->code)));
 189                 if (ndo->ndo_vflag <= 1)
 190                     print_unknown_data(ndo,cp+4,"\n\t",length-4);
 191                 break;
 192         }
 193
 194         if (SLARP_MAX_LEN < length && ndo->ndo_vflag)
 195                 ND_PRINT((ndo, ", (trailing junk: %d bytes)", length - SLARP_MAX_LEN));
 196         if (ndo->ndo_vflag > 1)
 197             print_unknown_data(ndo,cp+4,"\n\t",length-4);
 198         return;
 199
 200 trunc:
 201         ND_PRINT((ndo, "[|slarp]"));
 202 }
 203
 204
 205 /*
 206  * Local Variables:
 207  * c-style: whitesmith
 208  * c-basic-offset: 8
 209  * End:
 210  */