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 #ifdef HAVE_CONFIG_H
  23 #include "config.h"
  24 #endif
  25
  26 #include <netdissect-stdinc.h>
  27
  28 #include "netdissect.h"
  29 #include "extract.h"
  30
  31 #include "ip.h"
  32 #include "tcp.h"
  33 #include "slcompress.h"
  34
  35 /*
  36  * definitions of the pseudo- link-level header attached to slip
  37  * packets grabbed by the packet filter (bpf) traffic monitor.
  38  */
  39 #define SLIP_HDRLEN 16
  40
  41 #define SLX_DIR 0
  42 #define SLX_CHDR 1
  43 #define CHDR_LEN 15
  44
  45 #define SLIPDIR_IN 0
  46 #define SLIPDIR_OUT 1
  47
  48 static const char tstr[] = "[|slip]";
  49
  50 static u_int lastlen[2][256];
  51 static u_int lastconn = 255;
  52
  53 static void sliplink_print(netdissect_options *, const u_char *, const struct ip *, u_int);
  54 static void compressed_sl_print(netdissect_options *, const u_char *, const struct ip *, u_int, int);
  55
  56 u_int
  57 sl_if_print(netdissect_options *ndo,
  58             const struct pcap_pkthdr *h, const u_char *p)
  59 {
  60         register u_int caplen = h->caplen;
  61         register u_int length = h->len;
  62         register const struct ip *ip;
  63
  64         if (caplen < SLIP_HDRLEN || length < SLIP_HDRLEN) {
  65                 ND_PRINT((ndo, "%s", tstr));
  66                 return (caplen);
  67         }
  68
  69         length -= SLIP_HDRLEN;
  70
  71         ip = (const struct ip *)(p + SLIP_HDRLEN);
  72
  73         if (ndo->ndo_eflag)
  74                 sliplink_print(ndo, p, ip, length);
  75
  76         switch (IP_V(ip)) {
  77         case 4:
  78                 ip_print(ndo, (const u_char *)ip, length);
  79                 break;
  80         case 6:
  81                 ip6_print(ndo, (const u_char *)ip, length);
  82                 break;
  83         default:
  84                 ND_PRINT((ndo, "ip v%d", IP_V(ip)));
  85         }
  86
  87         return (SLIP_HDRLEN);
  88 }
  89
  90 u_int
  91 sl_bsdos_if_print(netdissect_options *ndo,
  92                   const struct pcap_pkthdr *h, const u_char *p)
  93 {
  94         register u_int caplen = h->caplen;
  95         register u_int length = h->len;
  96         register const struct ip *ip;
  97
  98         if (caplen < SLIP_HDRLEN) {
  99                 ND_PRINT((ndo, "%s", tstr));
 100                 return (caplen);
 101         }
 102
 103         length -= SLIP_HDRLEN;
 104
 105         ip = (const struct ip *)(p + SLIP_HDRLEN);
 106
 107 #ifdef notdef
 108         if (ndo->ndo_eflag)
 109                 sliplink_print(ndo, p, ip, length);
 110 #endif
 111
 112         ip_print(ndo, (const u_char *)ip, length);
 113
 114         return (SLIP_HDRLEN);
 115 }
 116
 117 static void
 118 sliplink_print(netdissect_options *ndo,
 119                register const u_char *p, register const struct ip *ip,
 120                register u_int length)
 121 {
 122         int dir;
 123         u_int hlen;
 124
 125         dir = p[SLX_DIR];
 126         ND_PRINT((ndo, dir == SLIPDIR_IN ? "I " : "O "));
 127
 128         if (ndo->ndo_nflag) {
 129                 /* XXX just dump the header */
 130                 register int i;
 131
 132                 for (i = SLX_CHDR; i < SLX_CHDR + CHDR_LEN - 1; ++i)
 133                         ND_PRINT((ndo, "%02x.", p[i]));
 134                 ND_PRINT((ndo, "%02x: ", p[SLX_CHDR + CHDR_LEN - 1]));
 135                 return;
 136         }
 137         switch (p[SLX_CHDR] & 0xf0) {
 138
 139         case TYPE_IP:
 140                 ND_PRINT((ndo, "ip %d: ", length + SLIP_HDRLEN));
 141                 break;
 142
 143         case TYPE_UNCOMPRESSED_TCP:
 144                 /*
 145                  * The connection id is stored in the IP protocol field.
 146                  * Get it from the link layer since sl_uncompress_tcp()
 147                  * has restored the IP header copy to IPPROTO_TCP.
 148                  */
 149                 lastconn = ((const struct ip *)&p[SLX_CHDR])->ip_p;
 150                 hlen = IP_HL(ip);
 151                 hlen += TH_OFF((const struct tcphdr *)&((const int *)ip)[hlen]);
 152                 lastlen[dir][lastconn] = length - (hlen << 2);
 153                 ND_PRINT((ndo, "utcp %d: ", lastconn));
 154                 break;
 155
 156         default:
 157                 if (p[SLX_CHDR] & TYPE_COMPRESSED_TCP) {
 158                         compressed_sl_print(ndo, &p[SLX_CHDR], ip,
 159                             length, dir);
 160                         ND_PRINT((ndo, ": "));
 161                 } else
 162                         ND_PRINT((ndo, "slip-%d!: ", p[SLX_CHDR]));
 163         }
 164 }
 165
 166 static const u_char *
 167 print_sl_change(netdissect_options *ndo,
 168                 const char *str, register const u_char *cp)
 169 {
 170         register u_int i;
 171
 172         if ((i = *cp++) == 0) {
 173                 i = EXTRACT_16BITS(cp);
 174                 cp += 2;
 175         }
 176         ND_PRINT((ndo, " %s%d", str, i));
 177         return (cp);
 178 }
 179
 180 static const u_char *
 181 print_sl_winchange(netdissect_options *ndo,
 182                    register const u_char *cp)
 183 {
 184         register short i;
 185
 186         if ((i = *cp++) == 0) {
 187                 i = EXTRACT_16BITS(cp);
 188                 cp += 2;
 189         }
 190         if (i >= 0)
 191                 ND_PRINT((ndo, " W+%d", i));
 192         else
 193                 ND_PRINT((ndo, " W%d", i));
 194         return (cp);
 195 }
 196
 197 static void
 198 compressed_sl_print(netdissect_options *ndo,
 199                     const u_char *chdr, const struct ip *ip,
 200                     u_int length, int dir)
 201 {
 202         register const u_char *cp = chdr;
 203         register u_int flags, hlen;
 204
 205         flags = *cp++;
 206         if (flags & NEW_C) {
 207                 lastconn = *cp++;
 208                 ND_PRINT((ndo, "ctcp %d", lastconn));
 209         } else
 210                 ND_PRINT((ndo, "ctcp *"));
 211
 212         /* skip tcp checksum */
 213         cp += 2;
 214
 215         switch (flags & SPECIALS_MASK) {
 216         case SPECIAL_I:
 217                 ND_PRINT((ndo, " *SA+%d", lastlen[dir][lastconn]));
 218                 break;
 219
 220         case SPECIAL_D:
 221                 ND_PRINT((ndo, " *S+%d", lastlen[dir][lastconn]));
 222                 break;
 223
 224         default:
 225                 if (flags & NEW_U)
 226                         cp = print_sl_change(ndo, "U=", cp);
 227                 if (flags & NEW_W)
 228                         cp = print_sl_winchange(ndo, cp);
 229                 if (flags & NEW_A)
 230                         cp = print_sl_change(ndo, "A+", cp);
 231                 if (flags & NEW_S)
 232                         cp = print_sl_change(ndo, "S+", cp);
 233                 break;
 234         }
 235         if (flags & NEW_I)
 236                 cp = print_sl_change(ndo, "I+", cp);
 237
 238         /*
 239          * 'hlen' is the length of the uncompressed TCP/IP header (in words).
 240          * 'cp - chdr' is the length of the compressed header.
 241          * 'length - hlen' is the amount of data in the packet.
 242          */
 243         hlen = IP_HL(ip);
 244         hlen += TH_OFF((const struct tcphdr *)&((const int32_t *)ip)[hlen]);
 245         lastlen[dir][lastconn] = length - (hlen << 2);
 246         ND_PRINT((ndo, " %d (%ld)", lastlen[dir][lastconn], (long)(cp - chdr)));
 247 }