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 int sliplink_print(netdissect_options *, const u_char *, const struct ip *, u_int);
  56 static int 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         register u_int caplen = h->caplen;
  63         register u_int length = h->len;
  64         register const struct ip *ip;
  65
  66         if (caplen < SLIP_HDRLEN || length < SLIP_HDRLEN) {
  67                 ND_PRINT((ndo, "%s", tstr));
  68                 return (caplen);
  69         }
  70
  71         caplen -= SLIP_HDRLEN;
  72         length -= SLIP_HDRLEN;
  73
  74         ip = (const struct ip *)(p + SLIP_HDRLEN);
  75
  76         if (ndo->ndo_eflag)
  77                 if (sliplink_print(ndo, p, ip, length) == -1) {
  78                         ND_PRINT((ndo, "%s", tstr));
  79                         return (caplen + SLIP_HDRLEN);
  80         }
  81
  82         if (caplen < 1 || length < 1) {
  83                 ND_PRINT((ndo, "%s", tstr));
  84                 return (caplen + SLIP_HDRLEN);
  85         }
  86
  87         switch (IP_V(ip)) {
  88         case 4:
  89                 ip_print(ndo, (const u_char *)ip, length);
  90                 break;
  91         case 6:
  92                 ip6_print(ndo, (const u_char *)ip, length);
  93                 break;
  94         default:
  95                 ND_PRINT((ndo, "ip v%d", IP_V(ip)));
  96         }
  97
  98         return (SLIP_HDRLEN);
  99 }
 100
 101 u_int
 102 sl_bsdos_if_print(netdissect_options *ndo,
 103                   const struct pcap_pkthdr *h, const u_char *p)
 104 {
 105         register u_int caplen = h->caplen;
 106         register u_int length = h->len;
 107         register const struct ip *ip;
 108
 109         if (caplen < SLIP_HDRLEN) {
 110                 ND_PRINT((ndo, "%s", tstr));
 111                 return (caplen);
 112         }
 113
 114         length -= SLIP_HDRLEN;
 115
 116         ip = (const struct ip *)(p + SLIP_HDRLEN);
 117
 118 #ifdef notdef
 119         if (ndo->ndo_eflag)
 120                 sliplink_print(ndo, p, ip, length);
 121 #endif
 122
 123         ip_print(ndo, (const u_char *)ip, length);
 124
 125         return (SLIP_HDRLEN);
 126 }
 127
 128 static int
 129 sliplink_print(netdissect_options *ndo,
 130                register const u_char *p, register const struct ip *ip,
 131                register u_int length)
 132 {
 133         int dir;
 134         u_int hlen;
 135
 136         dir = p[SLX_DIR];
 137         switch (dir) {
 138
 139         case SLIPDIR_IN:
 140                 ND_PRINT((ndo, "I "));
 141                 break;
 142
 143         case SLIPDIR_OUT:
 144                 ND_PRINT((ndo, "O "));
 145                 break;
 146
 147         default:
 148                 ND_PRINT((ndo, "Invalid direction %d ", dir));
 149                 dir = -1;
 150                 break;
 151         }
 152         if (ndo->ndo_nflag) {
 153                 /* XXX just dump the header */
 154                 register int i;
 155
 156                 for (i = SLX_CHDR; i < SLX_CHDR + CHDR_LEN - 1; ++i)
 157                         ND_PRINT((ndo, "%02x.", p[i]));
 158                 ND_PRINT((ndo, "%02x: ", p[SLX_CHDR + CHDR_LEN - 1]));
 159                 return 0;
 160         }
 161         switch (p[SLX_CHDR] & 0xf0) {
 162
 163         case TYPE_IP:
 164                 ND_PRINT((ndo, "ip %d: ", length + SLIP_HDRLEN));
 165                 break;
 166
 167         case TYPE_UNCOMPRESSED_TCP:
 168                 /*
 169                  * The connection id is stored in the IP protocol field.
 170                  * Get it from the link layer since sl_uncompress_tcp()
 171                  * has restored the IP header copy to IPPROTO_TCP.
 172                  */
 173                 lastconn = ((const struct ip *)&p[SLX_CHDR])->ip_p;
 174                 ND_PRINT((ndo, "utcp %d: ", lastconn));
 175                 if (dir == -1) {
 176                         /* Direction is bogus, don't use it */
 177                         return 0;
 178                 }
 179                 ND_TCHECK(*ip);
 180                 hlen = IP_HL(ip);
 181                 ND_TCHECK(*((const struct tcphdr *)&((const int *)ip)[hlen]));
 182                 hlen += TH_OFF((const struct tcphdr *)&((const int *)ip)[hlen]);
 183                 lastlen[dir][lastconn] = length - (hlen << 2);
 184                 break;
 185
 186         default:
 187                 if (dir == -1) {
 188                         /* Direction is bogus, don't use it */
 189                         return 0;
 190                 }
 191                 if (p[SLX_CHDR] & TYPE_COMPRESSED_TCP) {
 192                         if (compressed_sl_print(ndo, &p[SLX_CHDR], ip,
 193                                                 length, dir) == -1)
 194                                 goto trunc;
 195                         ND_PRINT((ndo, ": "));
 196                 } else
 197                         ND_PRINT((ndo, "slip-%d!: ", p[SLX_CHDR]));
 198         }
 199         return 0;
 200 trunc:
 201         return -1;
 202 }
 203
 204 static const u_char *
 205 print_sl_change(netdissect_options *ndo,
 206                 const char *str, register const u_char *cp)
 207 {
 208         register u_int i;
 209
 210         if ((i = *cp++) == 0) {
 211                 i = EXTRACT_16BITS(cp);
 212                 cp += 2;
 213         }
 214         ND_PRINT((ndo, " %s%d", str, i));
 215         return (cp);
 216 }
 217
 218 static const u_char *
 219 print_sl_winchange(netdissect_options *ndo,
 220                    register const u_char *cp)
 221 {
 222         register short i;
 223
 224         if ((i = *cp++) == 0) {
 225                 i = EXTRACT_16BITS(cp);
 226                 cp += 2;
 227         }
 228         if (i >= 0)
 229                 ND_PRINT((ndo, " W+%d", i));
 230         else
 231                 ND_PRINT((ndo, " W%d", i));
 232         return (cp);
 233 }
 234
 235 static int
 236 compressed_sl_print(netdissect_options *ndo,
 237                     const u_char *chdr, const struct ip *ip,
 238                     u_int length, int dir)
 239 {
 240         register const u_char *cp = chdr;
 241         register u_int flags, hlen;
 242
 243         flags = *cp++;
 244         if (flags & NEW_C) {
 245                 lastconn = *cp++;
 246                 ND_PRINT((ndo, "ctcp %d", lastconn));
 247         } else
 248                 ND_PRINT((ndo, "ctcp *"));
 249
 250         /* skip tcp checksum */
 251         cp += 2;
 252
 253         switch (flags & SPECIALS_MASK) {
 254         case SPECIAL_I:
 255                 ND_PRINT((ndo, " *SA+%d", lastlen[dir][lastconn]));
 256                 break;
 257
 258         case SPECIAL_D:
 259                 ND_PRINT((ndo, " *S+%d", lastlen[dir][lastconn]));
 260                 break;
 261
 262         default:
 263                 if (flags & NEW_U)
 264                         cp = print_sl_change(ndo, "U=", cp);
 265                 if (flags & NEW_W)
 266                         cp = print_sl_winchange(ndo, cp);
 267                 if (flags & NEW_A)
 268                         cp = print_sl_change(ndo, "A+", cp);
 269                 if (flags & NEW_S)
 270                         cp = print_sl_change(ndo, "S+", cp);
 271                 break;
 272         }
 273         if (flags & NEW_I)
 274                 cp = print_sl_change(ndo, "I+", cp);
 275
 276         /*
 277          * 'hlen' is the length of the uncompressed TCP/IP header (in words).
 278          * 'cp - chdr' is the length of the compressed header.
 279          * 'length - hlen' is the amount of data in the packet.
 280          */
 281         ND_TCHECK(*ip);
 282         hlen = IP_HL(ip);
 283         ND_TCHECK(*((const struct tcphdr *)&((const int32_t *)ip)[hlen]));
 284         hlen += TH_OFF((const struct tcphdr *)&((const int32_t *)ip)[hlen]);
 285         lastlen[dir][lastconn] = length - (hlen << 2);
 286         ND_PRINT((ndo, " %d (%ld)", lastlen[dir][lastconn], (long)(cp - chdr)));
 287         return 0;
 288 trunc:
 289         return -1;
 290 }