2 * Copyright (c) 1988-1997
3 * The Regents of the University of California. All rights reserved.
5 * Copyright (c) 1998-2012 Michael Richardson <mcr@tcpdump.org>
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that: (1) source code distributions
10 * retain the above copyright notice and this paragraph in its entirety, (2)
11 * distributions including binary code include the above copyright notice and
12 * this paragraph in its entirety in the documentation or other materials
13 * provided with the distribution, and (3) all advertising materials mentioning
14 * features or use of this software display the following acknowledgement:
15 * ``This product includes software developed by the University of California,
16 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
17 * the University nor the names of its contributors may be used to endorse
18 * or promote products derived from this software without specific prior
20 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
21 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
22 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
29 #include "netdissect-stdinc.h"
30 #include "netdissect.h"
40 * Initialize anything that must be initialized before dissecting
43 * This should be called at the beginning of the program; it does
44 * not need to be called, and should not be called, for every
45 * netdissect_options structure.
48 nd_init(char *errbuf, size_t errbuf_size)
51 WORD wVersionRequested;
56 * Request Winsock 2.2; we expect Winsock 2.
58 wVersionRequested = MAKEWORD(2, 2);
59 err = WSAStartup(wVersionRequested, &wsaData);
61 strlcpy(errbuf, "Attempting to initialize Winsock failed",
69 * XXX - should we just fail if this fails? Some of the
70 * libsmi calls may fail.
76 * Clears the error buffer, and uses it so we don't get
77 * "unused argument" warnings at compile time.
79 strlcpy(errbuf, "", errbuf_size);
84 * Clean up anything that ndo_init() did.
91 * This appears, in libsmi 0.4.8, to do nothing if smiInit()
92 * wasn't done or failed, so we call it unconditionally.
99 * Undo the WSAStartup() call above.
106 nd_have_smi_support(void)
116 * Indicates whether an SMI module has been loaded, so that we can use
117 * libsmi to translate OIDs.
119 int nd_smi_module_loaded;
122 nd_load_smi_module(const char *module, char *errbuf, size_t errbuf_size)
125 if (smiLoadModule(module) == 0) {
126 snprintf(errbuf, errbuf_size, "could not load MIB module %s",
130 nd_smi_module_loaded = 1;
133 snprintf(errbuf, errbuf_size, "MIB module %s not loaded: no libsmi support",
140 nd_smi_version_string(void)
143 return (smi_version_string);
151 nd_push_buffer(netdissect_options *ndo, u_char *new_buffer,
152 const u_char *new_packetp, const u_int newlen)
154 struct netdissect_saved_packet_info *ndspi;
156 ndspi = (struct netdissect_saved_packet_info *)malloc(sizeof(struct netdissect_saved_packet_info));
158 return (0); /* fail */
159 ndspi->ndspi_buffer = new_buffer;
160 ndspi->ndspi_packetp = ndo->ndo_packetp;
161 ndspi->ndspi_snapend = ndo->ndo_snapend;
162 ndspi->ndspi_prev = ndo->ndo_packet_info_stack;
164 ndo->ndo_packetp = new_packetp;
165 ndo->ndo_snapend = new_packetp + newlen;
166 ndo->ndo_packet_info_stack = ndspi;
168 return (1); /* success */
173 * In a given netdissect_options structure:
175 * push the current packet information onto the packet information
178 * given a pointer into the packet and a length past that point in
179 * the packet, calculate a new snapshot end that's at the lower
180 * of the current snapshot end and that point in the packet;
182 * set the snapshot end to that new value.
185 nd_push_snaplen(netdissect_options *ndo, const u_char *bp, const u_int newlen)
187 struct netdissect_saved_packet_info *ndspi;
188 u_int snaplen_remaining;
190 ndspi = (struct netdissect_saved_packet_info *)malloc(sizeof(struct netdissect_saved_packet_info));
192 return (0); /* fail */
193 ndspi->ndspi_buffer = NULL; /* no new buffer */
194 ndspi->ndspi_packetp = ndo->ndo_packetp;
195 ndspi->ndspi_snapend = ndo->ndo_snapend;
196 ndspi->ndspi_prev = ndo->ndo_packet_info_stack;
199 * Push the saved previous data onto the stack.
201 ndo->ndo_packet_info_stack = ndspi;
204 * Find out how many bytes remain after the current snapend.
206 * We're restricted to packets with at most UINT_MAX bytes;
207 * cast the result to u_int, so that we don't get truncation
208 * warnings on LP64 and LLP64 platforms. (ptrdiff_t is
209 * signed and we want an unsigned difference; the pointer
210 * should at most be equal to snapend, and must *never*
213 snaplen_remaining = (u_int)(ndo->ndo_snapend - bp);
216 * If the new snapend is smaller than the one calculated
217 * above, set the snapend to that value, otherwise leave
220 if (newlen <= snaplen_remaining) {
221 /* Snapend isn't past the previous snapend */
222 ndo->ndo_snapend = bp + newlen;
225 return (1); /* success */
229 * In a given netdissect_options structure:
231 * given a pointer into the packet and a length past that point in
232 * the packet, calculate a new snapshot end that's at the lower
233 * of the previous snapshot end - or, if there is no previous
234 * snapshot end, the current snapshot end - and that point in the
237 * set the snapshot end to that new value.
239 * This is to change the current snapshot end. This may increase the
240 * snapshot end, as it may be used, for example, for a Jumbo Payload
241 * option in IPv6. It must not increase it past the snapshot length
242 * atop which the current one was pushed, however.
245 nd_change_snaplen(netdissect_options *ndo, const u_char *bp, const u_int newlen)
247 struct netdissect_saved_packet_info *ndspi;
248 const u_char *previous_snapend;
249 u_int snaplen_remaining;
251 ndspi = ndo->ndo_packet_info_stack;
252 if (ndspi->ndspi_prev != NULL)
253 previous_snapend = ndspi->ndspi_prev->ndspi_snapend;
255 previous_snapend = ndo->ndo_snapend;
258 * Find out how many bytes remain after the previous
259 * snapend - or, if there is no previous snapend, after
260 * the current snapend.
262 * We're restricted to packets with at most UINT_MAX bytes;
263 * cast the result to u_int, so that we don't get truncation
264 * warnings on LP64 and LLP64 platforms. (ptrdiff_t is
265 * signed and we want an unsigned difference; the pointer
266 * should at most be equal to snapend, and must *never*
269 snaplen_remaining = (u_int)(previous_snapend - bp);
272 * If the new snapend is smaller than the one calculated
273 * above, set the snapend to that value, otherwise leave
276 if (newlen <= snaplen_remaining) {
277 /* Snapend isn't past the previous snapend */
278 ndo->ndo_snapend = bp + newlen;
283 nd_pop_packet_info(netdissect_options *ndo)
285 struct netdissect_saved_packet_info *ndspi;
287 ndspi = ndo->ndo_packet_info_stack;
288 ndo->ndo_packetp = ndspi->ndspi_packetp;
289 ndo->ndo_snapend = ndspi->ndspi_snapend;
290 ndo->ndo_packet_info_stack = ndspi->ndspi_prev;
292 free(ndspi->ndspi_buffer);
297 nd_pop_all_packet_info(netdissect_options *ndo)
299 while (ndo->ndo_packet_info_stack != NULL)
300 nd_pop_packet_info(ndo);