netdissect.c

/*
 * Copyright (c) 1988-1997
 *	The Regents of the University of California.  All rights reserved.
 *
 * Copyright (c) 1998-2012  Michael Richardson <mcr@tcpdump.org>
 *      The TCPDUMP project
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that: (1) source code distributions
 * retain the above copyright notice and this paragraph in its entirety, (2)
 * distributions including binary code include the above copyright notice and
 * this paragraph in its entirety in the documentation or other materials
 * provided with the distribution, and (3) all advertising materials mentioning
 * features or use of this software display the following acknowledgement:
 * ``This product includes software developed by the University of California,
 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
 * the University nor the names of its contributors may be used to endorse
 * or promote products derived from this software without specific prior
 * written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <netdissect-stdinc.h>
#include "netdissect.h"
#include <string.h>
#include <stdio.h>

#ifdef USE_LIBSMI
#include <smi.h>
#endif

/*
 * Initialize anything that must be initialized before dissecting
 * packets.
 *
 * This should be called at the beginning of the program; it does
 * not need to be called, and should not be called, for every
 * netdissect_options structure.
 */
int
nd_init(char *errbuf, size_t errbuf_size)
{
#ifdef _WIN32
	WORD wVersionRequested;
	WSADATA wsaData;
	int err;

	/*
	 * Request Winsock 2.2; we expect Winsock 2.
	 */
	wVersionRequested = MAKEWORD(2, 2);
	err = WSAStartup(wVersionRequested, &wsaData);
	if (err != 0) {
		strlcpy(errbuf, "Attempting to initialize Winsock failed",
		    errbuf_size);
		return (-1);
	}
#endif /* _WIN32 */

#ifdef USE_LIBSMI
	/*
	 * XXX - should we just fail if this fails?  Some of the
	 * libsmi calls may fail.
	 */
	smiInit("tcpdump");
#endif

	/*
	 * Clears the error buffer, and uses it so we don't get
	 * "unused argument" warnings at compile time.
	 */
	strlcpy(errbuf, "", errbuf_size);
	return (0);
}

/*
 * Clean up anything that ndo_init() did.
 */
void
nd_cleanup(void)
{
#ifdef USE_LIBSMI
	/*
	 * This appears, in libsmi 0.4.8, to do nothing if smiInit()
	 * wasn't done or failed, so we call it unconditionally.
	 */
	smiExit();
#endif

#ifdef _WIN32
	/*
	 * Undo the WSAStartup() call above.
	 */
	WSACleanup();
#endif
}

int
nd_have_smi_support(void)
{
#ifdef USE_LIBSMI
	return (1);
#else
	return (0);
#endif
}

/*
 * Indicates whether an SMI module has been loaded, so that we can use
 * libsmi to translate OIDs.
 */
int nd_smi_module_loaded;

int
nd_load_smi_module(const char *module, char *errbuf, size_t errbuf_size)
{
#ifdef USE_LIBSMI
	if (smiLoadModule(module) == 0) {
		snprintf(errbuf, errbuf_size, "could not load MIB module %s",
		    module);
		return (-1);
	}
	nd_smi_module_loaded = 1;
	return (0);
#else
	snprintf(errbuf, errbuf_size, "MIB module %s not loaded: no libsmi support",
	    module);
	return (-1);
#endif
}

const char *
nd_smi_version_string(void)
{
#ifdef USE_LIBSMI
	return (smi_version_string);
#else
	return (NULL);
#endif
}