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