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         ND_PRINT((ndo, dir == SLIPDIR_IN ? "I " : "O "));
 135
 136         if (ndo->ndo_nflag) {
 137                 /* XXX just dump the header */
 138                 register int i;
 139
 140                 for (i = SLX_CHDR; i < SLX_CHDR + CHDR_LEN - 1; ++i)
 141                         ND_PRINT((ndo, "%02x.", p[i]));
 142                 ND_PRINT((ndo, "%02x: ", p[SLX_CHDR + CHDR_LEN - 1]));
 143                 return;
 144         }
 145         switch (p[SLX_CHDR] & 0xf0) {
 146
 147         case TYPE_IP:
 148                 ND_PRINT((ndo, "ip %d: ", length + SLIP_HDRLEN));
 149                 break;
 150
 151         case TYPE_UNCOMPRESSED_TCP:
 152                 /*
 153                  * The connection id is stored in the IP protocol field.
 154                  * Get it from the link layer since sl_uncompress_tcp()
 155                  * has restored the IP header copy to IPPROTO_TCP.
 156                  */
 157                 lastconn = ((const struct ip *)&p[SLX_CHDR])->ip_p;
 158                 hlen = IP_HL(ip);
 159                 hlen += TH_OFF((const struct tcphdr *)&((const int *)ip)[hlen]);
 160                 lastlen[dir][lastconn] = length - (hlen << 2);
 161                 ND_PRINT((ndo, "utcp %d: ", lastconn));
 162                 break;
 163
 164         default:
 165                 if (p[SLX_CHDR] & TYPE_COMPRESSED_TCP) {
 166                         compressed_sl_print(ndo, &p[SLX_CHDR], ip,
 167                             length, dir);
 168                         ND_PRINT((ndo, ": "));
 169                 } else
 170                         ND_PRINT((ndo, "slip-%d!: ", p[SLX_CHDR]));
 171         }
 172 }
 173
 174 static const u_char *
 175 print_sl_change(netdissect_options *ndo,
 176                 const char *str, register const u_char *cp)
 177 {
 178         register u_int i;
 179
 180         if ((i = *cp++) == 0) {
 181                 i = EXTRACT_16BITS(cp);
 182                 cp += 2;
 183         }
 184         ND_PRINT((ndo, " %s%d", str, i));
 185         return (cp);
 186 }
 187
 188 static const u_char *
 189 print_sl_winchange(netdissect_options *ndo,
 190                    register const u_char *cp)
 191 {
 192         register short i;
 193
 194         if ((i = *cp++) == 0) {
 195                 i = EXTRACT_16BITS(cp);
 196                 cp += 2;
 197         }
 198         if (i >= 0)
 199                 ND_PRINT((ndo, " W+%d", i));
 200         else
 201                 ND_PRINT((ndo, " W%d", i));
 202         return (cp);
 203 }
 204
 205 static void
 206 compressed_sl_print(netdissect_options *ndo,
 207                     const u_char *chdr, const struct ip *ip,
 208                     u_int length, int dir)
 209 {
 210         register const u_char *cp = chdr;
 211         register u_int flags, hlen;
 212
 213         flags = *cp++;
 214         if (flags & NEW_C) {
 215                 lastconn = *cp++;
 216                 ND_PRINT((ndo, "ctcp %d", lastconn));
 217         } else
 218                 ND_PRINT((ndo, "ctcp *"));
 219
 220         /* skip tcp checksum */
 221         cp += 2;
 222
 223         switch (flags & SPECIALS_MASK) {
 224         case SPECIAL_I:
 225                 ND_PRINT((ndo, " *SA+%d", lastlen[dir][lastconn]));
 226                 break;
 227
 228         case SPECIAL_D:
 229                 ND_PRINT((ndo, " *S+%d", lastlen[dir][lastconn]));
 230                 break;
 231
 232         default:
 233                 if (flags & NEW_U)
 234                         cp = print_sl_change(ndo, "U=", cp);
 235                 if (flags & NEW_W)
 236                         cp = print_sl_winchange(ndo, cp);
 237                 if (flags & NEW_A)
 238                         cp = print_sl_change(ndo, "A+", cp);
 239                 if (flags & NEW_S)
 240                         cp = print_sl_change(ndo, "S+", cp);
 241                 break;
 242         }
 243         if (flags & NEW_I)
 244                 cp = print_sl_change(ndo, "I+", cp);
 245
 246         /*
 247          * 'hlen' is the length of the uncompressed TCP/IP header (in words).
 248          * 'cp - chdr' is the length of the compressed header.
 249          * 'length - hlen' is the amount of data in the packet.
 250          */
 251         hlen = IP_HL(ip);
 252         hlen += TH_OFF((const struct tcphdr *)&((const int32_t *)ip)[hlen]);
 253         lastlen[dir][lastconn] = length - (hlen << 2);
 254         ND_PRINT((ndo, " %d (%ld)", lastlen[dir][lastconn], (long)(cp - chdr)));
 255 }