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 #define NETDISSECT_REWORKED
  23 #ifdef HAVE_CONFIG_H
  24 #include "config.h"
  25 #endif
  26
  27 #include <tcpdump-stdinc.h>
  28
  29 #include "interface.h"
  30 #include "extract.h"                    /* must come after interface.h */
  31
  32 #include "ip.h"
  33 #include "tcp.h"
  34 #include "slcompress.h"
  35
  36 /*
  37  * definitions of the pseudo- link-level header attached to slip
  38  * packets grabbed by the packet filter (bpf) traffic monitor.
  39  */
  40 #define SLIP_HDRLEN 16
  41
  42 #define SLX_DIR 0
  43 #define SLX_CHDR 1
  44 #define CHDR_LEN 15
  45
  46 #define SLIPDIR_IN 0
  47 #define SLIPDIR_OUT 1
  48
  49 static const char tstr[] = "[|slip]";
  50
  51 static u_int lastlen[2][256];
  52 static u_int lastconn = 255;
  53
  54 static void sliplink_print(netdissect_options *, const u_char *, const struct ip *, u_int);
  55 static void compressed_sl_print(netdissect_options *, const u_char *, const struct ip *, u_int, int);
  56
  57 u_int
  58 sl_if_print(netdissect_options *ndo,
  59             const struct pcap_pkthdr *h, const u_char *p)
  60 {
  61         register u_int caplen = h->caplen;
  62         register u_int length = h->len;
  63         register const struct ip *ip;
  64
  65         if (caplen < SLIP_HDRLEN) {
  66                 ND_PRINT((ndo, "%s", tstr));
  67                 return (caplen);
  68         }
  69
  70         length -= SLIP_HDRLEN;
  71
  72         ip = (struct ip *)(p + SLIP_HDRLEN);
  73
  74         if (ndo->ndo_eflag)
  75                 sliplink_print(ndo, p, ip, length);
  76
  77         switch (IP_V(ip)) {
  78         case 4:
  79                 ip_print(ndo, (u_char *)ip, length);
  80                 break;
  81 #ifdef INET6
  82         case 6:
  83                 ip6_print(ndo, (u_char *)ip, length);
  84                 break;
  85 #endif
  86         default:
  87                 ND_PRINT((ndo, "ip v%d", IP_V(ip)));
  88         }
  89
  90         return (SLIP_HDRLEN);
  91 }
  92
  93 u_int
  94 sl_bsdos_if_print(netdissect_options *ndo,
  95                   const struct pcap_pkthdr *h, const u_char *p)
  96 {
  97         register u_int caplen = h->caplen;
  98         register u_int length = h->len;
  99         register const struct ip *ip;
 100
 101         if (caplen < SLIP_HDRLEN) {
 102                 ND_PRINT((ndo, "%s", tstr));
 103                 return (caplen);
 104         }
 105
 106         length -= SLIP_HDRLEN;
 107
 108         ip = (struct ip *)(p + SLIP_HDRLEN);
 109
 110 #ifdef notdef
 111         if (ndo->ndo_eflag)
 112                 sliplink_print(ndo, p, ip, length);
 113 #endif
 114
 115         ip_print(ndo, (u_char *)ip, length);
 116
 117         return (SLIP_HDRLEN);
 118 }
 119
 120 static void
 121 sliplink_print(netdissect_options *ndo,
 122                register const u_char *p, register const struct ip *ip,
 123                register u_int length)
 124 {
 125         int dir;
 126         u_int hlen;
 127
 128         dir = p[SLX_DIR];
 129         ND_PRINT((ndo, dir == SLIPDIR_IN ? "I " : "O "));
 130
 131         if (ndo->ndo_nflag) {
 132                 /* XXX just dump the header */
 133                 register int i;
 134
 135                 for (i = SLX_CHDR; i < SLX_CHDR + CHDR_LEN - 1; ++i)
 136                         ND_PRINT((ndo, "%02x.", p[i]));
 137                 ND_PRINT((ndo, "%02x: ", p[SLX_CHDR + CHDR_LEN - 1]));
 138                 return;
 139         }
 140         switch (p[SLX_CHDR] & 0xf0) {
 141
 142         case TYPE_IP:
 143                 ND_PRINT((ndo, "ip %d: ", length + SLIP_HDRLEN));
 144                 break;
 145
 146         case TYPE_UNCOMPRESSED_TCP:
 147                 /*
 148                  * The connection id is stored in the IP protocol field.
 149                  * Get it from the link layer since sl_uncompress_tcp()
 150                  * has restored the IP header copy to IPPROTO_TCP.
 151                  */
 152                 lastconn = ((struct ip *)&p[SLX_CHDR])->ip_p;
 153                 hlen = IP_HL(ip);
 154                 hlen += TH_OFF((struct tcphdr *)&((int *)ip)[hlen]);
 155                 lastlen[dir][lastconn] = length - (hlen << 2);
 156                 ND_PRINT((ndo, "utcp %d: ", lastconn));
 157                 break;
 158
 159         default:
 160                 if (p[SLX_CHDR] & TYPE_COMPRESSED_TCP) {
 161                         compressed_sl_print(ndo, &p[SLX_CHDR], ip,
 162                             length, dir);
 163                         ND_PRINT((ndo, ": "));
 164                 } else
 165                         ND_PRINT((ndo, "slip-%d!: ", p[SLX_CHDR]));
 166         }
 167 }
 168
 169 static const u_char *
 170 print_sl_change(netdissect_options *ndo,
 171                 const char *str, register const u_char *cp)
 172 {
 173         register u_int i;
 174
 175         if ((i = *cp++) == 0) {
 176                 i = EXTRACT_16BITS(cp);
 177                 cp += 2;
 178         }
 179         ND_PRINT((ndo, " %s%d", str, i));
 180         return (cp);
 181 }
 182
 183 static const u_char *
 184 print_sl_winchange(netdissect_options *ndo,
 185                    register const u_char *cp)
 186 {
 187         register short i;
 188
 189         if ((i = *cp++) == 0) {
 190                 i = EXTRACT_16BITS(cp);
 191                 cp += 2;
 192         }
 193         if (i >= 0)
 194                 ND_PRINT((ndo, " W+%d", i));
 195         else
 196                 ND_PRINT((ndo, " W%d", i));
 197         return (cp);
 198 }
 199
 200 static void
 201 compressed_sl_print(netdissect_options *ndo,
 202                     const u_char *chdr, const struct ip *ip,
 203                     u_int length, int dir)
 204 {
 205         register const u_char *cp = chdr;
 206         register u_int flags, hlen;
 207
 208         flags = *cp++;
 209         if (flags & NEW_C) {
 210                 lastconn = *cp++;
 211                 ND_PRINT((ndo, "ctcp %d", lastconn));
 212         } else
 213                 ND_PRINT((ndo, "ctcp *"));
 214
 215         /* skip tcp checksum */
 216         cp += 2;
 217
 218         switch (flags & SPECIALS_MASK) {
 219         case SPECIAL_I:
 220                 ND_PRINT((ndo, " *SA+%d", lastlen[dir][lastconn]));
 221                 break;
 222
 223         case SPECIAL_D:
 224                 ND_PRINT((ndo, " *S+%d", lastlen[dir][lastconn]));
 225                 break;
 226
 227         default:
 228                 if (flags & NEW_U)
 229                         cp = print_sl_change(ndo, "U=", cp);
 230                 if (flags & NEW_W)
 231                         cp = print_sl_winchange(ndo, cp);
 232                 if (flags & NEW_A)
 233                         cp = print_sl_change(ndo, "A+", cp);
 234                 if (flags & NEW_S)
 235                         cp = print_sl_change(ndo, "S+", cp);
 236                 break;
 237         }
 238         if (flags & NEW_I)
 239                 cp = print_sl_change(ndo, "I+", cp);
 240
 241         /*
 242          * 'hlen' is the length of the uncompressed TCP/IP header (in words).
 243          * 'cp - chdr' is the length of the compressed header.
 244          * 'length - hlen' is the amount of data in the packet.
 245          */
 246         hlen = IP_HL(ip);
 247         hlen += TH_OFF((struct tcphdr *)&((int32_t *)ip)[hlen]);
 248         lastlen[dir][lastconn] = length - (hlen << 2);
 249         ND_PRINT((ndo, " %d (%ld)", lastlen[dir][lastconn], (long)(cp - chdr)));
 250 }