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

   1 /*
   2  * Copyright (c) 1989, 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: Compressed Serial Line Internet Protocol 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 "extract.h"
  32
  33 #include "ip.h"
  34 #include "tcp.h"
  35 #include "slcompress.h"
  36
  37 /*
  38  * definitions of the pseudo- link-level header attached to slip
  39  * packets grabbed by the packet filter (bpf) traffic monitor.
  40  */
  41 #define SLIP_HDRLEN 16
  42
  43 #define SLX_DIR 0
  44 #define SLX_CHDR 1
  45 #define CHDR_LEN 15
  46
  47 #define SLIPDIR_IN 0
  48 #define SLIPDIR_OUT 1
  49
  50 static const char tstr[] = "[|slip]";
  51
  52 static u_int lastlen[2][256];
  53 static u_int lastconn = 255;
  54
  55 static void sliplink_print(netdissect_options *, const u_char *, const struct ip *, u_int);
  56 static void compressed_sl_print(netdissect_options *, const u_char *, const struct ip *, u_int, int);
  57
  58 u_int
  59 sl_if_print(netdissect_options *ndo,
  60             const struct pcap_pkthdr *h, const u_char *p)
  61 {
  62         u_int caplen = h->caplen;
  63         u_int length = h->len;
  64         const struct ip *ip;
  65
  66         ndo->ndo_protocol = "sl_if";
  67         if (caplen < SLIP_HDRLEN || length < SLIP_HDRLEN) {
  68                 ND_PRINT("%s", tstr);
  69                 return (caplen);
  70         }
  71
  72         caplen -= SLIP_HDRLEN;
  73         length -= SLIP_HDRLEN;
  74
  75         ip = (const struct ip *)(p + SLIP_HDRLEN);
  76
  77         if (ndo->ndo_eflag)
  78                 sliplink_print(ndo, p, ip, length);
  79
  80         if (caplen < 1 || length < 1) {
  81                 ND_PRINT("%s", tstr);
  82                 return (caplen + SLIP_HDRLEN);
  83         }
  84
  85         switch (IP_V(ip)) {
  86         case 4:
  87                 ip_print(ndo, (const u_char *)ip, length);
  88                 break;
  89         case 6:
  90                 ip6_print(ndo, (const u_char *)ip, length);
  91                 break;
  92         default:
  93                 ND_PRINT("ip v%u", IP_V(ip));
  94         }
  95
  96         return (SLIP_HDRLEN);
  97 }
  98
  99 u_int
 100 sl_bsdos_if_print(netdissect_options *ndo,
 101                   const struct pcap_pkthdr *h, const u_char *p)
 102 {
 103         u_int caplen = h->caplen;
 104         u_int length = h->len;
 105         const struct ip *ip;
 106
 107         ndo->ndo_protocol = "sl_bsdos_if";
 108         if (caplen < SLIP_HDRLEN) {
 109                 ND_PRINT("%s", tstr);
 110                 return (caplen);
 111         }
 112
 113         length -= SLIP_HDRLEN;
 114
 115         ip = (const struct ip *)(p + SLIP_HDRLEN);
 116
 117 #ifdef notdef
 118         if (ndo->ndo_eflag)
 119                 sliplink_print(ndo, p, ip, length);
 120 #endif
 121
 122         ip_print(ndo, (const u_char *)ip, length);
 123
 124         return (SLIP_HDRLEN);
 125 }
 126
 127 static void
 128 sliplink_print(netdissect_options *ndo,
 129                const u_char *p, const struct ip *ip,
 130                u_int length)
 131 {
 132         int dir;
 133         u_int hlen;
 134
 135         dir = EXTRACT_U_1(p + SLX_DIR);
 136         switch (dir) {
 137
 138         case SLIPDIR_IN:
 139                 ND_PRINT("I ");
 140                 break;
 141
 142         case SLIPDIR_OUT:
 143                 ND_PRINT("O ");
 144                 break;
 145
 146         default:
 147                 ND_PRINT("Invalid direction %d ", dir);
 148                 dir = -1;
 149                 break;
 150         }
 151         if (ndo->ndo_nflag) {
 152                 /* XXX just dump the header */
 153                 int i;
 154
 155                 for (i = SLX_CHDR; i < SLX_CHDR + CHDR_LEN - 1; ++i)
 156                         ND_PRINT("%02x.", EXTRACT_U_1(p + i));
 157                 ND_PRINT("%02x: ", EXTRACT_U_1(p + SLX_CHDR + CHDR_LEN - 1));
 158                 return;
 159         }
 160         switch (EXTRACT_U_1(p + SLX_CHDR) & 0xf0) {
 161
 162         case TYPE_IP:
 163                 ND_PRINT("ip %u: ", length + SLIP_HDRLEN);
 164                 break;
 165
 166         case TYPE_UNCOMPRESSED_TCP:
 167                 /*
 168                  * The connection id is stored in the IP protocol field.
 169                  * Get it from the link layer since sl_uncompress_tcp()
 170                  * has restored the IP header copy to IPPROTO_TCP.
 171                  */
 172                 lastconn = EXTRACT_U_1(((const struct ip *)(p + SLX_CHDR))->ip_p);
 173                 ND_PRINT("utcp %u: ", lastconn);
 174                 if (dir == -1) {
 175                         /* Direction is bogus, don't use it */
 176                         return;
 177                 }
 178                 hlen = IP_HL(ip);
 179                 hlen += TH_OFF((const struct tcphdr *)&((const int *)ip)[hlen]);
 180                 lastlen[dir][lastconn] = length - (hlen << 2);
 181                 break;
 182
 183         default:
 184                 if (dir == -1) {
 185                         /* Direction is bogus, don't use it */
 186                         return;
 187                 }
 188                 if (EXTRACT_U_1(p + SLX_CHDR) & TYPE_COMPRESSED_TCP) {
 189                         compressed_sl_print(ndo, p + SLX_CHDR, ip,
 190                                             length, dir);
 191                         ND_PRINT(": ");
 192                 } else
 193                         ND_PRINT("slip-%u!: ", EXTRACT_U_1(p + SLX_CHDR));
 194         }
 195 }
 196
 197 static const u_char *
 198 print_sl_change(netdissect_options *ndo,
 199                 const char *str, const u_char *cp)
 200 {
 201         u_int i;
 202
 203         if ((i = EXTRACT_U_1(cp)) == 0) {
 204                 cp++;
 205                 i = EXTRACT_BE_U_2(cp);
 206                 cp += 2;
 207         }
 208         ND_PRINT(" %s%u", str, i);
 209         return (cp);
 210 }
 211
 212 static const u_char *
 213 print_sl_winchange(netdissect_options *ndo,
 214                    const u_char *cp)
 215 {
 216         int16_t i;
 217
 218         if ((i = EXTRACT_U_1(cp)) == 0) {
 219                 cp++;
 220                 i = EXTRACT_BE_S_2(cp);
 221                 cp += 2;
 222         }
 223         if (i >= 0)
 224                 ND_PRINT(" W+%d", i);
 225         else
 226                 ND_PRINT(" W%d", i);
 227         return (cp);
 228 }
 229
 230 static void
 231 compressed_sl_print(netdissect_options *ndo,
 232                     const u_char *chdr, const struct ip *ip,
 233                     u_int length, int dir)
 234 {
 235         const u_char *cp = chdr;
 236         u_int flags, hlen;
 237
 238         flags = EXTRACT_U_1(cp);
 239         cp++;
 240         if (flags & NEW_C) {
 241                 lastconn = EXTRACT_U_1(cp);
 242                 cp++;
 243                 ND_PRINT("ctcp %u", lastconn);
 244         } else
 245                 ND_PRINT("ctcp *");
 246
 247         /* skip tcp checksum */
 248         cp += 2;
 249
 250         switch (flags & SPECIALS_MASK) {
 251         case SPECIAL_I:
 252                 ND_PRINT(" *SA+%u", lastlen[dir][lastconn]);
 253                 break;
 254
 255         case SPECIAL_D:
 256                 ND_PRINT(" *S+%u", lastlen[dir][lastconn]);
 257                 break;
 258
 259         default:
 260                 if (flags & NEW_U)
 261                         cp = print_sl_change(ndo, "U=", cp);
 262                 if (flags & NEW_W)
 263                         cp = print_sl_winchange(ndo, cp);
 264                 if (flags & NEW_A)
 265                         cp = print_sl_change(ndo, "A+", cp);
 266                 if (flags & NEW_S)
 267                         cp = print_sl_change(ndo, "S+", cp);
 268                 break;
 269         }
 270         if (flags & NEW_I)
 271                 cp = print_sl_change(ndo, "I+", cp);
 272
 273         /*
 274          * 'hlen' is the length of the uncompressed TCP/IP header (in words).
 275          * 'cp - chdr' is the length of the compressed header.
 276          * 'length - hlen' is the amount of data in the packet.
 277          */
 278         hlen = IP_HL(ip);
 279         hlen += TH_OFF((const struct tcphdr *)&((const int32_t *)ip)[hlen]);
 280         lastlen[dir][lastconn] = length - (hlen << 2);
 281         ND_PRINT(" %u (%ld)", lastlen[dir][lastconn], (long)(cp - chdr));
 282 }