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