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