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         length -= SLIP_HDRLEN;
  72
  73         ip = (const struct ip *)(p + SLIP_HDRLEN);
  74
  75         if (ndo->ndo_eflag)
  76                 sliplink_print(ndo, p, ip, length);
  77
  78         switch (IP_V(ip)) {
  79         case 4:
  80                 ip_print(ndo, (const u_char *)ip, length);
  81                 break;
  82         case 6:
  83                 ip6_print(ndo, (const u_char *)ip, length);
  84                 break;
  85         default:
  86                 ND_PRINT((ndo, "ip v%d", IP_V(ip)));
  87         }
  88
  89         return (SLIP_HDRLEN);
  90 }
  91
  92 u_int
  93 sl_bsdos_if_print(netdissect_options *ndo,
  94                   const struct pcap_pkthdr *h, const u_char *p)
  95 {
  96         register u_int caplen = h->caplen;
  97         register u_int length = h->len;
  98         register const struct ip *ip;
  99
 100         if (caplen < SLIP_HDRLEN) {
 101                 ND_PRINT((ndo, "%s", tstr));
 102                 return (caplen);
 103         }
 104
 105         length -= SLIP_HDRLEN;
 106
 107         ip = (const struct ip *)(p + SLIP_HDRLEN);
 108
 109 #ifdef notdef
 110         if (ndo->ndo_eflag)
 111                 sliplink_print(ndo, p, ip, length);
 112 #endif
 113
 114         ip_print(ndo, (const u_char *)ip, length);
 115
 116         return (SLIP_HDRLEN);
 117 }
 118
 119 static void
 120 sliplink_print(netdissect_options *ndo,
 121                register const u_char *p, register const struct ip *ip,
 122                register u_int length)
 123 {
 124         int dir;
 125         u_int hlen;
 126
 127         dir = p[SLX_DIR];
 128         ND_PRINT((ndo, dir == SLIPDIR_IN ? "I " : "O "));
 129
 130         if (ndo->ndo_nflag) {
 131                 /* XXX just dump the header */
 132                 register int i;
 133
 134                 for (i = SLX_CHDR; i < SLX_CHDR + CHDR_LEN - 1; ++i)
 135                         ND_PRINT((ndo, "%02x.", p[i]));
 136                 ND_PRINT((ndo, "%02x: ", p[SLX_CHDR + CHDR_LEN - 1]));
 137                 return;
 138         }
 139         switch (p[SLX_CHDR] & 0xf0) {
 140
 141         case TYPE_IP:
 142                 ND_PRINT((ndo, "ip %d: ", length + SLIP_HDRLEN));
 143                 break;
 144
 145         case TYPE_UNCOMPRESSED_TCP:
 146                 /*
 147                  * The connection id is stored in the IP protocol field.
 148                  * Get it from the link layer since sl_uncompress_tcp()
 149                  * has restored the IP header copy to IPPROTO_TCP.
 150                  */
 151                 lastconn = ((const struct ip *)&p[SLX_CHDR])->ip_p;
 152                 hlen = IP_HL(ip);
 153                 hlen += TH_OFF((const struct tcphdr *)&((const int *)ip)[hlen]);
 154                 lastlen[dir][lastconn] = length - (hlen << 2);
 155                 ND_PRINT((ndo, "utcp %d: ", lastconn));
 156                 break;
 157
 158         default:
 159                 if (p[SLX_CHDR] & TYPE_COMPRESSED_TCP) {
 160                         compressed_sl_print(ndo, &p[SLX_CHDR], ip,
 161                             length, dir);
 162                         ND_PRINT((ndo, ": "));
 163                 } else
 164                         ND_PRINT((ndo, "slip-%d!: ", p[SLX_CHDR]));
 165         }
 166 }
 167
 168 static const u_char *
 169 print_sl_change(netdissect_options *ndo,
 170                 const char *str, register const u_char *cp)
 171 {
 172         register u_int i;
 173
 174         if ((i = *cp++) == 0) {
 175                 i = EXTRACT_16BITS(cp);
 176                 cp += 2;
 177         }
 178         ND_PRINT((ndo, " %s%d", str, i));
 179         return (cp);
 180 }
 181
 182 static const u_char *
 183 print_sl_winchange(netdissect_options *ndo,
 184                    register const u_char *cp)
 185 {
 186         register short i;
 187
 188         if ((i = *cp++) == 0) {
 189                 i = EXTRACT_16BITS(cp);
 190                 cp += 2;
 191         }
 192         if (i >= 0)
 193                 ND_PRINT((ndo, " W+%d", i));
 194         else
 195                 ND_PRINT((ndo, " W%d", i));
 196         return (cp);
 197 }
 198
 199 static void
 200 compressed_sl_print(netdissect_options *ndo,
 201                     const u_char *chdr, const struct ip *ip,
 202                     u_int length, int dir)
 203 {
 204         register const u_char *cp = chdr;
 205         register u_int flags, hlen;
 206
 207         flags = *cp++;
 208         if (flags & NEW_C) {
 209                 lastconn = *cp++;
 210                 ND_PRINT((ndo, "ctcp %d", lastconn));
 211         } else
 212                 ND_PRINT((ndo, "ctcp *"));
 213
 214         /* skip tcp checksum */
 215         cp += 2;
 216
 217         switch (flags & SPECIALS_MASK) {
 218         case SPECIAL_I:
 219                 ND_PRINT((ndo, " *SA+%d", lastlen[dir][lastconn]));
 220                 break;
 221
 222         case SPECIAL_D:
 223                 ND_PRINT((ndo, " *S+%d", lastlen[dir][lastconn]));
 224                 break;
 225
 226         default:
 227                 if (flags & NEW_U)
 228                         cp = print_sl_change(ndo, "U=", cp);
 229                 if (flags & NEW_W)
 230                         cp = print_sl_winchange(ndo, cp);
 231                 if (flags & NEW_A)
 232                         cp = print_sl_change(ndo, "A+", cp);
 233                 if (flags & NEW_S)
 234                         cp = print_sl_change(ndo, "S+", cp);
 235                 break;
 236         }
 237         if (flags & NEW_I)
 238                 cp = print_sl_change(ndo, "I+", cp);
 239
 240         /*
 241          * 'hlen' is the length of the uncompressed TCP/IP header (in words).
 242          * 'cp - chdr' is the length of the compressed header.
 243          * 'length - hlen' is the amount of data in the packet.
 244          */
 245         hlen = IP_HL(ip);
 246         hlen += TH_OFF((const struct tcphdr *)&((const int32_t *)ip)[hlen]);
 247         lastlen[dir][lastconn] = length - (hlen << 2);
 248         ND_PRINT((ndo, " %d (%ld)", lastlen[dir][lastconn], (long)(cp - chdr)));
 249 }