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 <tcpdump-stdinc.h>
  27
  28 #include <pcap.h>
  29 #include <stdio.h>
  30
  31 #include "interface.h"
  32 #include "extract.h"                    /* must come after interface.h */
  33
  34 #include "ip.h"
  35 #include "tcp.h"
  36 #include "slcompress.h"
  37
  38 /*
  39  * definitions of the pseudo- link-level header attached to slip
  40  * packets grabbed by the packet filter (bpf) traffic monitor.
  41  */
  42 #define SLIP_HDRLEN 16
  43
  44 #define SLX_DIR 0
  45 #define SLX_CHDR 1
  46 #define CHDR_LEN 15
  47
  48 #define SLIPDIR_IN 0
  49 #define SLIPDIR_OUT 1
  50
  51 static const char tstr[] = "[|slip]";
  52
  53 static u_int lastlen[2][256];
  54 static u_int lastconn = 255;
  55
  56 static void sliplink_print(const u_char *, const struct ip *, u_int);
  57 static void compressed_sl_print(const u_char *, const struct ip *, u_int, int);
  58
  59 u_int
  60 sl_if_print(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) {
  67                 printf("%s", tstr);
  68                 return (caplen);
  69         }
  70
  71         length -= SLIP_HDRLEN;
  72
  73         ip = (struct ip *)(p + SLIP_HDRLEN);
  74
  75         if (eflag)
  76                 sliplink_print(p, ip, length);
  77
  78         switch (IP_V(ip)) {
  79         case 4:
  80                 ip_print(gndo, (u_char *)ip, length);
  81                 break;
  82 #ifdef INET6
  83         case 6:
  84                 ip6_print(gndo, (u_char *)ip, length);
  85                 break;
  86 #endif
  87         default:
  88                 printf ("ip v%d", IP_V(ip));
  89         }
  90
  91         return (SLIP_HDRLEN);
  92 }
  93
  94 u_int
  95 sl_bsdos_if_print(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                 printf("%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 (eflag)
 112                 sliplink_print(p, ip, length);
 113 #endif
 114
 115         ip_print(gndo, (u_char *)ip, length);
 116
 117         return (SLIP_HDRLEN);
 118 }
 119
 120 static void
 121 sliplink_print(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         putchar(dir == SLIPDIR_IN ? 'I' : 'O');
 129         putchar(' ');
 130
 131         if (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                         printf("%02x.", p[i]);
 137                 printf("%02x: ", p[SLX_CHDR + CHDR_LEN - 1]);
 138                 return;
 139         }
 140         switch (p[SLX_CHDR] & 0xf0) {
 141
 142         case TYPE_IP:
 143                 printf("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                 printf("utcp %d: ", lastconn);
 157                 break;
 158
 159         default:
 160                 if (p[SLX_CHDR] & TYPE_COMPRESSED_TCP) {
 161                         compressed_sl_print(&p[SLX_CHDR], ip,
 162                             length, dir);
 163                         printf(": ");
 164                 } else
 165                         printf("slip-%d!: ", p[SLX_CHDR]);
 166         }
 167 }
 168
 169 static const u_char *
 170 print_sl_change(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         printf(" %s%d", str, i);
 179         return (cp);
 180 }
 181
 182 static const u_char *
 183 print_sl_winchange(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                 printf(" W+%d", i);
 193         else
 194                 printf(" W%d", i);
 195         return (cp);
 196 }
 197
 198 static void
 199 compressed_sl_print(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                 printf("ctcp %d", lastconn);
 209         } else
 210                 printf("ctcp *");
 211
 212         /* skip tcp checksum */
 213         cp += 2;
 214
 215         switch (flags & SPECIALS_MASK) {
 216         case SPECIAL_I:
 217                 printf(" *SA+%d", lastlen[dir][lastconn]);
 218                 break;
 219
 220         case SPECIAL_D:
 221                 printf(" *S+%d", lastlen[dir][lastconn]);
 222                 break;
 223
 224         default:
 225                 if (flags & NEW_U)
 226                         cp = print_sl_change("U=", cp);
 227                 if (flags & NEW_W)
 228                         cp = print_sl_winchange(cp);
 229                 if (flags & NEW_A)
 230                         cp = print_sl_change("A+", cp);
 231                 if (flags & NEW_S)
 232                         cp = print_sl_change("S+", cp);
 233                 break;
 234         }
 235         if (flags & NEW_I)
 236                 cp = print_sl_change("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((struct tcphdr *)&((int32_t *)ip)[hlen]);
 245         lastlen[dir][lastconn] = length - (hlen << 2);
 246         printf(" %d (%ld)", lastlen[dir][lastconn], (long)(cp - chdr));
 247 }