tcpdump  4.99.1
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print-sl.c
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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 #define ND_LONGJMP_FROM_TCHECK
31 #include "netdissect.h"
32 #include "extract.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 
47 #define SLIPDIR_IN 0
48 #define SLIPDIR_OUT 1
49 
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 void
59  const struct pcap_pkthdr *h, const u_char *p)
60 {
61  u_int length = h->len;
62  const struct ip *ip;
63 
64  ndo->ndo_protocol = "slip";
67 
68  length -= SLIP_HDRLEN;
69 
70  ip = (const struct ip *)(p + SLIP_HDRLEN);
71 
72  if (ndo->ndo_eflag)
73  sliplink_print(ndo, p, ip, length);
74 
75  switch (IP_V(ip)) {
76  case 4:
77  ip_print(ndo, (const u_char *)ip, length);
78  break;
79  case 6:
80  ip6_print(ndo, (const u_char *)ip, length);
81  break;
82  default:
83  ND_PRINT("ip v%u", IP_V(ip));
84  }
85 }
86 
87 void
89  const struct pcap_pkthdr *h, const u_char *p)
90 {
91  u_int length = h->len;
92  const struct ip *ip;
93 
94  ndo->ndo_protocol = "slip_bsdos";
97 
98  length -= SLIP_HDRLEN;
99 
100  ip = (const struct ip *)(p + SLIP_HDRLEN);
101 
102 #ifdef notdef
103  if (ndo->ndo_eflag)
104  sliplink_print(ndo, p, ip, length);
105 #endif
106 
107  ip_print(ndo, (const u_char *)ip, length);
108 }
109 
110 static void
112  const u_char *p, const struct ip *ip,
113  u_int length)
114 {
115  int dir;
116  u_int hlen;
117 
118  dir = GET_U_1(p + SLX_DIR);
119  switch (dir) {
120 
121  case SLIPDIR_IN:
122  ND_PRINT("I ");
123  break;
124 
125  case SLIPDIR_OUT:
126  ND_PRINT("O ");
127  break;
128 
129  default:
130  ND_PRINT("Invalid direction %d ", dir);
131  dir = -1;
132  break;
133  }
134  switch (GET_U_1(p + SLX_CHDR) & 0xf0) {
135 
136  case TYPE_IP:
137  ND_PRINT("ip %u: ", length + SLIP_HDRLEN);
138  break;
139 
141  /*
142  * The connection id is stored in the IP protocol field.
143  * Get it from the link layer since sl_uncompress_tcp()
144  * has restored the IP header copy to IPPROTO_TCP.
145  */
146  lastconn = GET_U_1(((const struct ip *)(p + SLX_CHDR))->ip_p);
147  ND_PRINT("utcp %u: ", lastconn);
148  if (dir == -1) {
149  /* Direction is bogus, don't use it */
150  return;
151  }
153  hlen = IP_HL(ip);
154  ND_TCHECK_SIZE((const struct tcphdr *)&((const int *)ip)[hlen]);
155  hlen += TH_OFF((const struct tcphdr *)&((const int *)ip)[hlen]);
156  lastlen[dir][lastconn] = length - (hlen << 2);
157  break;
158 
159  default:
160  if (dir == -1) {
161  /* Direction is bogus, don't use it */
162  return;
163  }
164  if (GET_U_1(p + SLX_CHDR) & TYPE_COMPRESSED_TCP) {
165  compressed_sl_print(ndo, p + SLX_CHDR, ip, length, dir);
166  ND_PRINT(": ");
167  } else
168  ND_PRINT("slip-%u!: ", GET_U_1(p + SLX_CHDR));
169  }
170 }
171 
172 static const u_char *
174  const char *str, const u_char *cp)
175 {
176  u_int i;
177 
178  if ((i = GET_U_1(cp)) == 0) {
179  cp++;
180  i = GET_BE_U_2(cp);
181  cp += 2;
182  }
183  ND_PRINT(" %s%u", str, i);
184  return (cp);
185 }
186 
187 static const u_char *
189  const u_char *cp)
190 {
191  int16_t i;
192 
193  if ((i = GET_U_1(cp)) == 0) {
194  cp++;
195  i = GET_BE_S_2(cp);
196  cp += 2;
197  }
198  if (i >= 0)
199  ND_PRINT(" W+%d", i);
200  else
201  ND_PRINT(" W%d", i);
202  return (cp);
203 }
204 
205 static void
207  const u_char *chdr, const struct ip *ip,
208  u_int length, int dir)
209 {
210  const u_char *cp = chdr;
211  u_int flags, hlen;
212 
213  flags = GET_U_1(cp);
214  cp++;
215  if (flags & NEW_C) {
216  lastconn = GET_U_1(cp);
217  cp++;
218  ND_PRINT("ctcp %u", lastconn);
219  } else
220  ND_PRINT("ctcp *");
221 
222  /* skip tcp checksum */
223  cp += 2;
224 
225  switch (flags & SPECIALS_MASK) {
226  case SPECIAL_I:
227  ND_PRINT(" *SA+%u", lastlen[dir][lastconn]);
228  break;
229 
230  case SPECIAL_D:
231  ND_PRINT(" *S+%u", lastlen[dir][lastconn]);
232  break;
233 
234  default:
235  if (flags & NEW_U)
236  cp = print_sl_change(ndo, "U=", cp);
237  if (flags & NEW_W)
238  cp = print_sl_winchange(ndo, cp);
239  if (flags & NEW_A)
240  cp = print_sl_change(ndo, "A+", cp);
241  if (flags & NEW_S)
242  cp = print_sl_change(ndo, "S+", cp);
243  break;
244  }
245  if (flags & NEW_I)
246  cp = print_sl_change(ndo, "I+", cp);
247 
248  /*
249  * 'hlen' is the length of the uncompressed TCP/IP header (in words).
250  * 'cp - chdr' is the length of the compressed header.
251  * 'length - hlen' is the amount of data in the packet.
252  */
254  hlen = IP_HL(ip);
255  ND_TCHECK_SIZE((const struct tcphdr *)&((const int32_t *)ip)[hlen]);
256  hlen += TH_OFF((const struct tcphdr *)&((const int32_t *)ip)[hlen]);
257  lastlen[dir][lastconn] = length - (hlen << 2);
258  ND_PRINT(" %u (%ld)", lastlen[dir][lastconn], (long)(cp - chdr));
259 }
#define GET_BE_U_2(p)
Definition: extract.h:875
#define GET_BE_S_2(p)
Definition: extract.h:883
#define GET_U_1(p)
Definition: extract.h:872
#define IP_HL(ip)
Definition: ip.h:55
#define IP_V(ip)
Definition: ip.h:54
void ip6_print(netdissect_options *, const u_char *, u_int)
Definition: print-ip6.c:226
#define ND_TCHECK_LEN(p, l)
Definition: netdissect.h:368
#define ND_TCHECK_SIZE(p)
Definition: netdissect.h:372
void ip_print(netdissect_options *, const u_char *, u_int)
Definition: print-ip.c:319
#define ND_PRINT(...)
Definition: netdissect.h:385
static u_int lastlen[2][256]
Definition: print-sl.c:51
static void compressed_sl_print(netdissect_options *, const u_char *, const struct ip *, u_int, int)
Definition: print-sl.c:206
void sl_bsdos_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
Definition: print-sl.c:88
static u_int lastconn
Definition: print-sl.c:52
#define SLIPDIR_OUT
Definition: print-sl.c:48
void sl_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
Definition: print-sl.c:58
#define SLIP_HDRLEN
Definition: print-sl.c:42
#define SLX_DIR
Definition: print-sl.c:44
static const u_char * print_sl_winchange(netdissect_options *ndo, const u_char *cp)
Definition: print-sl.c:188
static const u_char * print_sl_change(netdissect_options *ndo, const char *str, const u_char *cp)
Definition: print-sl.c:173
static void sliplink_print(netdissect_options *, const u_char *, const struct ip *, u_int)
Definition: print-sl.c:111
#define SLX_CHDR
Definition: print-sl.c:45
#define SLIPDIR_IN
Definition: print-sl.c:47
#define TYPE_UNCOMPRESSED_TCP
Definition: slcompress.h:68
#define NEW_I
Definition: slcompress.h:74
#define TYPE_COMPRESSED_TCP
Definition: slcompress.h:69
#define SPECIALS_MASK
Definition: slcompress.h:83
#define NEW_C
Definition: slcompress.h:73
#define NEW_U
Definition: slcompress.h:78
#define TYPE_IP
Definition: slcompress.h:67
#define NEW_W
Definition: slcompress.h:77
#define NEW_S
Definition: slcompress.h:75
#define SPECIAL_D
Definition: slcompress.h:82
#define SPECIAL_I
Definition: slcompress.h:81
#define NEW_A
Definition: slcompress.h:76
Definition: ip.h:52
nd_uint8_t ip_p
Definition: ip.h:64
const char * ndo_protocol
Definition: netdissect.h:218
Definition: tcp.h:40
#define TH_OFF(th)
Definition: tcp.h:52