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

   1 /*
   2  * Copyright (c) 1992, 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  * Code by Matt Thomas, Digital Equipment Corporation
  22  *      with an awful lot of hacking by Jeffrey Mogul, DECWRL
  23  */
  24
  25 #ifndef lint
  26 static const char rcsid[] =
  27     "@(#) $Header: /tcpdump/master/tcpdump/print-llc.c,v 1.24 1999-10-07 23:47:11 mcr Exp $";
  28 #endif
  29
  30 #include <sys/param.h>
  31 #include <sys/time.h>
  32
  33 #include <netinet/in.h>
  34
  35 #include <ctype.h>
  36 #include <netdb.h>
  37 #include <stdio.h>
  38 #include <string.h>
  39
  40 #include "interface.h"
  41 #include "addrtoname.h"
  42 #include "extract.h"                    /* must come after interface.h */
  43
  44 #include "llc.h"
  45
  46 static struct tok cmd2str[] = {
  47         { LLC_UI,       "ui" },
  48         { LLC_TEST,     "test" },
  49         { LLC_XID,      "xid" },
  50         { LLC_UA,       "ua" },
  51         { LLC_DISC,     "disc" },
  52         { LLC_DM,       "dm" },
  53         { LLC_SABME,    "sabme" },
  54         { LLC_FRMR,     "frmr" },
  55         { 0,            NULL }
  56 };
  57
  58 /*
  59  * Returns non-zero IFF it succeeds in printing the header
  60  */
  61 int
  62 llc_print(const u_char *p, u_int length, u_int caplen,
  63           const u_char *esrc, const u_char *edst)
  64 {
  65         struct llc llc;
  66         register u_short et;
  67         register int ret;
  68
  69         if (caplen < 3) {
  70                 (void)printf("[|llc]");
  71                 default_print((u_char *)p, caplen);
  72                 return(0);
  73         }
  74
  75         /* Watch out for possible alignment problems */
  76         memcpy((char *)&llc, (char *)p, min(caplen, sizeof(llc)));
  77
  78         if (llc.ssap == LLCSAP_GLOBAL && llc.dsap == LLCSAP_GLOBAL) {
  79                 ipx_print(p, length);
  80                 return (1);
  81         }
  82 #ifdef notyet
  83         else if (p[0] == 0xf0 && p[1] == 0xf0)
  84                 netbios_print(p, length);
  85 #endif
  86         if (llc.ssap == LLCSAP_ISONS && llc.dsap == LLCSAP_ISONS
  87             && llc.llcui == LLC_UI) {
  88                 isoclns_print(p + 3, length - 3, caplen - 3, esrc, edst);
  89                 return (1);
  90         }
  91
  92         if (llc.ssap == LLCSAP_SNAP && llc.dsap == LLCSAP_SNAP
  93             && llc.llcui == LLC_UI) {
  94                 if (caplen < sizeof(llc)) {
  95                     (void)printf("[|llc-snap]");
  96                     default_print((u_char *)p, caplen);
  97                     return (0);
  98                 }
  99                 if (vflag)
 100                         (void)printf("snap %s ", protoid_string(llc.llcpi));
 101
 102                 caplen -= sizeof(llc);
 103                 length -= sizeof(llc);
 104                 p += sizeof(llc);
 105
 106                 /* This is an encapsulated Ethernet packet */
 107                 et = EXTRACT_16BITS(&llc.ethertype[0]);
 108                 ret = ether_encap_print(et, p, length, caplen);
 109                 if (ret)
 110                         return (ret);
 111         }
 112
 113         if ((llc.ssap & ~LLC_GSAP) == llc.dsap) {
 114                 if (eflag)
 115                         (void)printf("%s ", llcsap_string(llc.dsap));
 116                 else
 117                         (void)printf("%s > %s %s ",
 118                                         etheraddr_string(esrc),
 119                                         etheraddr_string(edst),
 120                                         llcsap_string(llc.dsap));
 121         } else {
 122                 if (eflag)
 123                         (void)printf("%s > %s ",
 124                                 llcsap_string(llc.ssap & ~LLC_GSAP),
 125                                 llcsap_string(llc.dsap));
 126                 else
 127                         (void)printf("%s %s > %s %s ",
 128                                 etheraddr_string(esrc),
 129                                 llcsap_string(llc.ssap & ~LLC_GSAP),
 130                                 etheraddr_string(edst),
 131                                 llcsap_string(llc.dsap));
 132         }
 133
 134         if ((llc.llcu & LLC_U_FMT) == LLC_U_FMT) {
 135                 const char *m;
 136                 char f;
 137                 m = tok2str(cmd2str, "%02x", LLC_U_CMD(llc.llcu));
 138                 switch ((llc.ssap & LLC_GSAP) | (llc.llcu & LLC_U_POLL)) {
 139                     case 0:                     f = 'C'; break;
 140                     case LLC_GSAP:              f = 'R'; break;
 141                     case LLC_U_POLL:            f = 'P'; break;
 142                     case LLC_GSAP|LLC_U_POLL:   f = 'F'; break;
 143                     default:                    f = '?'; break;
 144                 }
 145
 146                 printf("%s/%c", m, f);
 147
 148                 p += 3;
 149                 length -= 3;
 150                 caplen -= 3;
 151
 152                 if ((llc.llcu & ~LLC_U_POLL) == LLC_XID) {
 153                     if (*p == LLC_XID_FI) {
 154                         printf(": %02x %02x", p[1], p[2]);
 155                         p += 3;
 156                         length -= 3;
 157                         caplen -= 3;
 158                     }
 159                 }
 160         } else {
 161                 char f;
 162                 llc.llcis = ntohs(llc.llcis);
 163                 switch ((llc.ssap & LLC_GSAP) | (llc.llcu & LLC_U_POLL)) {
 164                     case 0:                     f = 'C'; break;
 165                     case LLC_GSAP:              f = 'R'; break;
 166                     case LLC_U_POLL:            f = 'P'; break;
 167                     case LLC_GSAP|LLC_U_POLL:   f = 'F'; break;
 168                     default:                    f = '?'; break;
 169                 }
 170
 171                 if ((llc.llcu & LLC_S_FMT) == LLC_S_FMT) {
 172                         static char *llc_s[] = { "rr", "rej", "rnr", "03" };
 173                         (void)printf("%s (r=%d,%c)",
 174                                 llc_s[LLC_S_CMD(llc.llcis)],
 175                                 LLC_IS_NR(llc.llcis),
 176                                 f);
 177                 } else {
 178                         (void)printf("I (s=%d,r=%d,%c)",
 179                                 LLC_I_NS(llc.llcis),
 180                                 LLC_IS_NR(llc.llcis),
 181                                 f);
 182                 }
 183                 p += 4;
 184                 length -= 4;
 185                 caplen -= 4;
 186         }
 187         (void)printf(" len=%d", length);
 188         if (caplen > 0) {
 189                 default_print_unaligned(p, caplen);
 190         }
 191         return(1);
 192 }