tcpdump-4.3.0/print-esp.c - nest-learning-thermostat/5.1.7/tcpdump - Git at Google

 /*	$NetBSD: print-ah.c,v 1.4 1996/05/20 00:41:16 fvdl Exp $	*/

 /*
  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994
  *	The Regents of the University of California.  All rights reserved.
  *
  * 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.
  */

 #ifndef lint
 static const char rcsid[] _U_ =
     "@(#) $Header: /tcpdump/master/tcpdump/print-esp.c,v 1.58 2007-12-07 00:03:07 mcr Exp $ (LBL)";
 #endif

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

 #include <string.h>

 #include <tcpdump-stdinc.h>

 #include <stdlib.h>

 #ifdef HAVE_LIBCRYPTO
 #ifdef HAVE_OPENSSL_EVP_H
 #include <openssl/evp.h>
 #endif
 #endif

 #include <stdio.h>

 #include "ip.h"
 #include "esp.h"
 #ifdef INET6
 #include "ip6.h"
 #endif

 #include "netdissect.h"
 #include "addrtoname.h"
 #include "extract.h"

 #ifndef HAVE_SOCKADDR_STORAGE
 #ifdef INET6
 struct sockaddr_storage {
 	union {
 		struct sockaddr_in sin;
 		struct sockaddr_in6 sin6;
 	} un;
 };
 #else
 #define sockaddr_storage sockaddr
 #endif
 #endif /* HAVE_SOCKADDR_STORAGE */

 #ifdef HAVE_LIBCRYPTO
 struct sa_list {
 	struct sa_list	*next;
 	struct sockaddr_storage daddr;
 	u_int32_t	spi;          /* if == 0, then IKEv2 */
 	int             initiator;
 	u_char          spii[8];      /* for IKEv2 */
 	u_char          spir[8];
 	const EVP_CIPHER *evp;
 	int		ivlen;
 	int		authlen;
 	u_char          authsecret[256];
 	int             authsecret_len;
 	u_char		secret[256];  /* is that big enough for all secrets? */
 	int		secretlen;
 };

 /*
  * this will adjust ndo_packetp and ndo_snapend to new buffer!
  */
 int esp_print_decrypt_buffer_by_ikev2(netdissect_options *ndo,
 				      int initiator,
 				      u_char spii[8], u_char spir[8],
 				      u_char *buf, u_char *end)
 {
 	struct sa_list *sa;
 	u_char *iv;
 	int len;
 	EVP_CIPHER_CTX ctx;

 	/* initiator arg is any non-zero value */
 	if(initiator) initiator=1;

 	/* see if we can find the SA, and if so, decode it */
 	for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) {
 		if (sa->spi == 0
 		    && initiator == sa->initiator
 		    && memcmp(spii, sa->spii, 8) == 0
 		    && memcmp(spir, sa->spir, 8) == 0)
 			break;
 	}

 	if(sa == NULL) return 0;
 	if(sa->evp == NULL) return 0;

 	/*
 	 * remove authenticator, and see if we still have something to
 	 * work with
 	 */
 	end = end - sa->authlen;
 	iv  = buf;
 	buf = buf + sa->ivlen;
 	len = end-buf;

 	if(end <= buf) return 0;

 	memset(&ctx, 0, sizeof(ctx));
 	if (EVP_CipherInit(&ctx, sa->evp, sa->secret, NULL, 0) < 0)
 		(*ndo->ndo_warning)(ndo, "espkey init failed");
 	EVP_CipherInit(&ctx, NULL, NULL, iv, 0);
 	EVP_Cipher(&ctx, buf, buf, len);
 	EVP_CIPHER_CTX_cleanup(&ctx);

 	ndo->ndo_packetp = buf;
 	ndo->ndo_snapend = end;

 	return 1;

 }

 static void esp_print_addsa(netdissect_options *ndo,
 			    struct sa_list *sa, int sa_def)
 {
 	/* copy the "sa" */

 	struct sa_list *nsa;

 	nsa = (struct sa_list *)malloc(sizeof(struct sa_list));
 	if (nsa == NULL)
 		(*ndo->ndo_error)(ndo, "ran out of memory to allocate sa structure");

 	*nsa = *sa;

 	if (sa_def)
 		ndo->ndo_sa_default = nsa;

 	nsa->next = ndo->ndo_sa_list_head;
 	ndo->ndo_sa_list_head = nsa;
 }


 static u_int hexdigit(netdissect_options *ndo, char hex)
 {
 	if (hex >= '0' && hex <= '9')
 		return (hex - '0');
 	else if (hex >= 'A' && hex <= 'F')
 		return (hex - 'A' + 10);
 	else if (hex >= 'a' && hex <= 'f')
 		return (hex - 'a' + 10);
 	else {
 		(*ndo->ndo_error)(ndo, "invalid hex digit %c in espsecret\n", hex);
 		return 0;
 	}
 }

 static u_int hex2byte(netdissect_options *ndo, char *hexstring)
 {
 	u_int byte;

 	byte = (hexdigit(ndo, hexstring[0]) << 4) + hexdigit(ndo, hexstring[1]);
 	return byte;
 }

 /*
  * returns size of binary, 0 on failure.
  */
 static
 int espprint_decode_hex(netdissect_options *ndo,
 			u_char *binbuf, unsigned int binbuf_len,
 			char *hex)
 {
 	unsigned int len;
 	int i;

 	len = strlen(hex) / 2;

 	if (len > binbuf_len) {
 		(*ndo->ndo_warning)(ndo, "secret is too big: %d\n", len);
 		return 0;
 	}

 	i = 0;
 	while (hex[0] != '\0' && hex[1]!='\0') {
 		binbuf[i] = hex2byte(ndo, hex);
 		hex += 2;
 		i++;
 	}

 	return i;
 }

 /*
  * decode the form:    SPINUM@IP <tab> ALGONAME:0xsecret
  */

 static int
 espprint_decode_encalgo(netdissect_options *ndo,
 			char *decode, struct sa_list *sa)
 {
 	int len;
 	size_t i;
 	const EVP_CIPHER *evp;
 	int authlen = 0;
 	char *colon, *p;

 	colon = strchr(decode, ':');
 	if (colon == NULL) {
 		(*ndo->ndo_warning)(ndo, "failed to decode espsecret: %s\n", decode);
 		return 0;
 	}
 	*colon = '\0';

 	len = colon - decode;
 	if (strlen(decode) > strlen("-hmac96") &&
 	    !strcmp(decode + strlen(decode) - strlen("-hmac96"),
 		    "-hmac96")) {
 		p = strstr(decode, "-hmac96");
 		*p = '\0';
 		authlen = 12;
 	}
 	if (strlen(decode) > strlen("-cbc") &&
 	    !strcmp(decode + strlen(decode) - strlen("-cbc"), "-cbc")) {
 		p = strstr(decode, "-cbc");
 		*p = '\0';
 	}
 	evp = EVP_get_cipherbyname(decode);

 	if (!evp) {
 		(*ndo->ndo_warning)(ndo, "failed to find cipher algo %s\n", decode);
 		sa->evp = NULL;
 		sa->authlen = 0;
 		sa->ivlen = 0;
 		return 0;
 	}

 	sa->evp = evp;
 	sa->authlen = authlen;
 	sa->ivlen = EVP_CIPHER_iv_length(evp);

 	colon++;
 	if (colon[0] == '0' && colon[1] == 'x') {
 		/* decode some hex! */

 		colon += 2;
 		sa->secretlen = espprint_decode_hex(ndo, sa->secret, sizeof(sa->secret), colon);
 		if(sa->secretlen == 0) return 0;
 	} else {
 		i = strlen(colon);

 		if (i < sizeof(sa->secret)) {
 			memcpy(sa->secret, colon, i);
 			sa->secretlen = i;
 		} else {
 			memcpy(sa->secret, colon, sizeof(sa->secret));
 			sa->secretlen = sizeof(sa->secret);
 		}
 	}

 	return 1;
 }

 /*
  * for the moment, ignore the auth algorith, just hard code the authenticator
  * length. Need to research how openssl looks up HMAC stuff.
  */
 static int
 espprint_decode_authalgo(netdissect_options *ndo,
 			 char *decode, struct sa_list *sa)
 {
 	char *colon;

 	colon = strchr(decode, ':');
 	if (colon == NULL) {
 		(*ndo->ndo_warning)(ndo, "failed to decode espsecret: %s\n", decode);
 		return 0;
 	}
 	*colon = '\0';

 	if(strcasecmp(colon,"sha1") == 0 ||
 	   strcasecmp(colon,"md5") == 0) {
 		sa->authlen = 12;
 	}
 	return 1;
 }

 static void esp_print_decode_ikeline(netdissect_options *ndo, char *line,
 				     const char *file, int lineno)
 {
 	/* it's an IKEv2 secret, store it instead */
 	struct sa_list sa1;

 	char *init;
 	char *icookie, *rcookie;
 	int   ilen, rlen;
 	char *authkey;
 	char *enckey;

 	init = strsep(&line, " \t");
 	icookie = strsep(&line, " \t");
 	rcookie = strsep(&line, " \t");
 	authkey = strsep(&line, " \t");
 	enckey  = strsep(&line, " \t");

 	/* if any fields are missing */
 	if(!init || !icookie || !rcookie || !authkey || !enckey) {
 		(*ndo->ndo_warning)(ndo, "print_esp: failed to find all fields for ikev2 at %s:%u",
 				    file, lineno);

 		return;
 	}

 	ilen = strlen(icookie);
 	rlen = strlen(rcookie);

 	if((init[0]!='I' && init[0]!='R')
 	   || icookie[0]!='0' || icookie[1]!='x'
 	   || rcookie[0]!='0' || rcookie[1]!='x'
 	   || ilen!=18
 	   || rlen!=18) {
 		(*ndo->ndo_warning)(ndo, "print_esp: line %s:%u improperly formatted.",
 				    file, lineno);

 		(*ndo->ndo_warning)(ndo, "init=%s icookie=%s(%u) rcookie=%s(%u)",
 				    init, icookie, ilen, rcookie, rlen);

 		return;
 	}

 	sa1.spi = 0;
 	sa1.initiator = (init[0] == 'I');
 	if(espprint_decode_hex(ndo, sa1.spii, sizeof(sa1.spii), icookie+2)!=8)
 		return;

 	if(espprint_decode_hex(ndo, sa1.spir, sizeof(sa1.spir), rcookie+2)!=8)
 		return;

 	if(!espprint_decode_encalgo(ndo, enckey, &sa1)) return;

 	if(!espprint_decode_authalgo(ndo, authkey, &sa1)) return;

 	esp_print_addsa(ndo, &sa1, FALSE);
 }

 /*
  *
  * special form: file /name
  * causes us to go read from this file instead.
  *
  */
 static void esp_print_decode_onesecret(netdissect_options *ndo, char *line,
 				       const char *file, int lineno)
 {
 	struct sa_list sa1;
 	int sa_def;

 	char *spikey;
 	char *decode;

 	spikey = strsep(&line, " \t");
 	sa_def = 0;
 	memset(&sa1, 0, sizeof(struct sa_list));

 	/* if there is only one token, then it is an algo:key token */
 	if (line == NULL) {
 		decode = spikey;
 		spikey = NULL;
 		/* memset(&sa1.daddr, 0, sizeof(sa1.daddr)); */
 		/* sa1.spi = 0; */
 		sa_def    = 1;
 	} else
 		decode = line;

 	if (spikey && strcasecmp(spikey, "file") == 0) {
 		/* open file and read it */
 		FILE *secretfile;
 		char  fileline[1024];
 		int   lineno=0;
 		char  *nl;
 		char *filename = line;

 		secretfile = fopen(filename, FOPEN_READ_TXT);
 		if (secretfile == NULL) {
 			perror(filename);
 			exit(3);
 		}

 		while (fgets(fileline, sizeof(fileline)-1, secretfile) != NULL) {
 			lineno++;
 			/* remove newline from the line */
 			nl = strchr(fileline, '\n');
 			if (nl)
 				*nl = '\0';
 			if (fileline[0] == '#') continue;
 			if (fileline[0] == '\0') continue;

 			esp_print_decode_onesecret(ndo, fileline, filename, lineno);
 		}
 		fclose(secretfile);

 		return;
 	}

 	if (spikey && strcasecmp(spikey, "ikev2") == 0) {
 		esp_print_decode_ikeline(ndo, line, file, lineno);
 		return;
 	}

 	if (spikey) {

 		char *spistr, *foo;
 		u_int32_t spino;
 		struct sockaddr_in *sin;
 #ifdef INET6
 		struct sockaddr_in6 *sin6;
 #endif

 		spistr = strsep(&spikey, "@");

 		spino = strtoul(spistr, &foo, 0);
 		if (spistr == foo || !spikey) {
 			(*ndo->ndo_warning)(ndo, "print_esp: failed to decode spi# %s\n", foo);
 			return;
 		}

 		sa1.spi = spino;

 		sin = (struct sockaddr_in *)&sa1.daddr;
 #ifdef INET6
 		sin6 = (struct sockaddr_in6 *)&sa1.daddr;
 		if (inet_pton(AF_INET6, spikey, &sin6->sin6_addr) == 1) {
 #ifdef HAVE_SOCKADDR_SA_LEN
 			sin6->sin6_len = sizeof(struct sockaddr_in6);
 #endif
 			sin6->sin6_family = AF_INET6;
 		} else
 #endif
 			if (inet_pton(AF_INET, spikey, &sin->sin_addr) == 1) {
 #ifdef HAVE_SOCKADDR_SA_LEN
 				sin->sin_len = sizeof(struct sockaddr_in);
 #endif
 				sin->sin_family = AF_INET;
 			} else {
 				(*ndo->ndo_warning)(ndo, "print_esp: can not decode IP# %s\n", spikey);
 				return;
 			}
 	}

 	if (decode) {
 		/* skip any blank spaces */
 		while (isspace((unsigned char)*decode))
 			decode++;

 		if(!espprint_decode_encalgo(ndo, decode, &sa1)) {
 			return;
 		}
 	}

 	esp_print_addsa(ndo, &sa1, sa_def);
 }

 static void esp_init(netdissect_options *ndo _U_)
 {

 	OpenSSL_add_all_algorithms();
 	EVP_add_cipher_alias(SN_des_ede3_cbc, "3des");
 }

 void esp_print_decodesecret(netdissect_options *ndo)
 {
 	char *line;
 	char *p;
 	static int initialized = 0;

 	if (!initialized) {
 		esp_init(ndo);
 		initialized = 1;
 	}

 	p = ndo->ndo_espsecret;

 	while (p && p[0] != '\0') {
 		/* pick out the first line or first thing until a comma */
 		if ((line = strsep(&p, "\n,")) == NULL) {
 			line = p;
 			p = NULL;
 		}

 		esp_print_decode_onesecret(ndo, line, "cmdline", 0);
 	}

 	ndo->ndo_espsecret = NULL;
 }

 #endif

 int
 esp_print(netdissect_options *ndo,
 	  const u_char *bp, const int length, const u_char *bp2
 #ifndef HAVE_LIBCRYPTO
 	_U_
 #endif
 	,
 	int *nhdr
 #ifndef HAVE_LIBCRYPTO
 	_U_
 #endif
 	,
 	int *padlen
 #ifndef HAVE_LIBCRYPTO
 	_U_
 #endif
 	)
 {
 	register const struct newesp *esp;
 	register const u_char *ep;
 #ifdef HAVE_LIBCRYPTO
 	struct ip *ip;
 	struct sa_list *sa = NULL;
 	int espsecret_keylen;
 #ifdef INET6
 	struct ip6_hdr *ip6 = NULL;
 #endif
 	int advance;
 	int len;
 	u_char *secret;
 	int ivlen = 0;
 	u_char *ivoff;
 	u_char *p;
 	EVP_CIPHER_CTX ctx;
 	int blocksz;
 #endif

 	esp = (struct newesp *)bp;

 #ifdef HAVE_LIBCRYPTO
 	secret = NULL;
 	advance = 0;
 #endif

 #if 0
 	/* keep secret out of a register */
 	p = (u_char *)&secret;
 #endif

 	/* 'ep' points to the end of available data. */
 	ep = ndo->ndo_snapend;

 	if ((u_char *)(esp + 1) >= ep) {
 		fputs("[|ESP]", stdout);
 		goto fail;
 	}
 	(*ndo->ndo_printf)(ndo, "ESP(spi=0x%08x", EXTRACT_32BITS(&esp->esp_spi));
 	(*ndo->ndo_printf)(ndo, ",seq=0x%x)", EXTRACT_32BITS(&esp->esp_seq));
         (*ndo->ndo_printf)(ndo, ", length %u", length);

 #ifndef HAVE_LIBCRYPTO
 	goto fail;
 #else
 	/* initiailize SAs */
 	if (ndo->ndo_sa_list_head == NULL) {
 		if (!ndo->ndo_espsecret)
 			goto fail;

 		esp_print_decodesecret(ndo);
 	}

 	if (ndo->ndo_sa_list_head == NULL)
 		goto fail;

 	ip = (struct ip *)bp2;
 	switch (IP_V(ip)) {
 #ifdef INET6
 	case 6:
 		ip6 = (struct ip6_hdr *)bp2;
 		/* we do not attempt to decrypt jumbograms */
 		if (!EXTRACT_16BITS(&ip6->ip6_plen))
 			goto fail;
 		/* if we can't get nexthdr, we do not need to decrypt it */
 		len = sizeof(struct ip6_hdr) + EXTRACT_16BITS(&ip6->ip6_plen);

 		/* see if we can find the SA, and if so, decode it */
 		for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) {
 			struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&sa->daddr;
 			if (sa->spi == EXTRACT_32BITS(&esp->esp_spi) &&
 			    sin6->sin6_family == AF_INET6 &&
 			    memcmp(&sin6->sin6_addr, &ip6->ip6_dst,
 				   sizeof(struct in6_addr)) == 0) {
 				break;
 			}
 		}
 		break;
 #endif /*INET6*/
 	case 4:
 		/* nexthdr & padding are in the last fragment */
 		if (EXTRACT_16BITS(&ip->ip_off) & IP_MF)
 			goto fail;
 		len = EXTRACT_16BITS(&ip->ip_len);

 		/* see if we can find the SA, and if so, decode it */
 		for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) {
 			struct sockaddr_in *sin = (struct sockaddr_in *)&sa->daddr;
 			if (sa->spi == EXTRACT_32BITS(&esp->esp_spi) &&
 			    sin->sin_family == AF_INET &&
 			    sin->sin_addr.s_addr == ip->ip_dst.s_addr) {
 				break;
 			}
 		}
 		break;
 	default:
 		goto fail;
 	}

 	/* if we didn't find the specific one, then look for
 	 * an unspecified one.
 	 */
 	if (sa == NULL)
 		sa = ndo->ndo_sa_default;

 	/* if not found fail */
 	if (sa == NULL)
 		goto fail;

 	/* if we can't get nexthdr, we do not need to decrypt it */
 	if (ep - bp2 < len)
 		goto fail;
 	if (ep - bp2 > len) {
 		/* FCS included at end of frame (NetBSD 1.6 or later) */
 		ep = bp2 + len;
 	}

 	ivoff = (u_char *)(esp + 1) + 0;
 	ivlen = sa->ivlen;
 	secret = sa->secret;
 	espsecret_keylen = sa->secretlen;
 	ep = ep - sa->authlen;

 	if (sa->evp) {
 		memset(&ctx, 0, sizeof(ctx));
 		if (EVP_CipherInit(&ctx, sa->evp, secret, NULL, 0) < 0)
 			(*ndo->ndo_warning)(ndo, "espkey init failed");

 		blocksz = EVP_CIPHER_CTX_block_size(&ctx);

 		p = ivoff;
 		EVP_CipherInit(&ctx, NULL, NULL, p, 0);
 		EVP_Cipher(&ctx, p + ivlen, p + ivlen, ep - (p + ivlen));
 		EVP_CIPHER_CTX_cleanup(&ctx);
 		advance = ivoff - (u_char *)esp + ivlen;
 	} else
 		advance = sizeof(struct newesp);

 	/* sanity check for pad length */
 	if (ep - bp < *(ep - 2))
 		goto fail;

 	if (padlen)
 		*padlen = *(ep - 2) + 2;

 	if (nhdr)
 		*nhdr = *(ep - 1);

 	(ndo->ndo_printf)(ndo, ": ");
 	return advance;
 #endif

 fail:
 	return -1;
 }

 /*
  * Local Variables:
  * c-style: whitesmith
  * c-basic-offset: 8
  * End:
  */
	/* $NetBSD: print-ah.c,v 1.4 1996/05/20 00:41:16 fvdl Exp $ */

	/*
	* Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994
	* The Regents of the University of California. All rights reserved.
	*
	* 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.
	*/

	#ifndef lint
	static const char rcsid[] _U_ =
	"@(#) $Header: /tcpdump/master/tcpdump/print-esp.c,v 1.58 2007-12-07 00:03:07 mcr Exp $ (LBL)";
	#endif

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

	#include <string.h>

	#include <tcpdump-stdinc.h>

	#include <stdlib.h>

	#ifdef HAVE_LIBCRYPTO
	#ifdef HAVE_OPENSSL_EVP_H
	#include <openssl/evp.h>
	#endif
	#endif

	#include <stdio.h>

	#include "ip.h"
	#include "esp.h"
	#ifdef INET6
	#include "ip6.h"
	#endif

	#include "netdissect.h"
	#include "addrtoname.h"
	#include "extract.h"

	#ifndef HAVE_SOCKADDR_STORAGE
	#ifdef INET6
	struct sockaddr_storage {
	union {
	struct sockaddr_in sin;
	struct sockaddr_in6 sin6;
	} un;
	};
	#else
	#define sockaddr_storage sockaddr
	#endif
	#endif /* HAVE_SOCKADDR_STORAGE */

	#ifdef HAVE_LIBCRYPTO
	struct sa_list {
	struct sa_list *next;
	struct sockaddr_storage daddr;
	u_int32_t spi; /* if == 0, then IKEv2 */
	int initiator;
	u_char spii[8]; /* for IKEv2 */
	u_char spir[8];
	const EVP_CIPHER *evp;
	int ivlen;
	int authlen;
	u_char authsecret[256];
	int authsecret_len;
	u_char secret[256]; /* is that big enough for all secrets? */
	int secretlen;
	};

	/*
	* this will adjust ndo_packetp and ndo_snapend to new buffer!
	*/
	int esp_print_decrypt_buffer_by_ikev2(netdissect_options *ndo,
	int initiator,
	u_char spii[8], u_char spir[8],
	u_char buf, u_char end)
	{
	struct sa_list *sa;
	u_char *iv;
	int len;
	EVP_CIPHER_CTX ctx;

	/* initiator arg is any non-zero value */
	if(initiator) initiator=1;

	/* see if we can find the SA, and if so, decode it */
	for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) {
	if (sa->spi == 0
	&& initiator == sa->initiator
	&& memcmp(spii, sa->spii, 8) == 0
	&& memcmp(spir, sa->spir, 8) == 0)
	break;
	}

	if(sa == NULL) return 0;
	if(sa->evp == NULL) return 0;

	/*
	* remove authenticator, and see if we still have something to
	* work with
	*/
	end = end - sa->authlen;
	iv = buf;
	buf = buf + sa->ivlen;
	len = end-buf;

	if(end <= buf) return 0;

	memset(&ctx, 0, sizeof(ctx));
	if (EVP_CipherInit(&ctx, sa->evp, sa->secret, NULL, 0) < 0)
	(*ndo->ndo_warning)(ndo, "espkey init failed");
	EVP_CipherInit(&ctx, NULL, NULL, iv, 0);
	EVP_Cipher(&ctx, buf, buf, len);
	EVP_CIPHER_CTX_cleanup(&ctx);

	ndo->ndo_packetp = buf;
	ndo->ndo_snapend = end;

	return 1;

	}

	static void esp_print_addsa(netdissect_options *ndo,
	struct sa_list *sa, int sa_def)
	{
	/* copy the "sa" */

	struct sa_list *nsa;

	nsa = (struct sa_list *)malloc(sizeof(struct sa_list));
	if (nsa == NULL)
	(*ndo->ndo_error)(ndo, "ran out of memory to allocate sa structure");

	nsa = sa;

	if (sa_def)
	ndo->ndo_sa_default = nsa;

	nsa->next = ndo->ndo_sa_list_head;
	ndo->ndo_sa_list_head = nsa;
	}


	static u_int hexdigit(netdissect_options *ndo, char hex)
	{
	if (hex >= '0' && hex <= '9')
	return (hex - '0');
	else if (hex >= 'A' && hex <= 'F')
	return (hex - 'A' + 10);
	else if (hex >= 'a' && hex <= 'f')
	return (hex - 'a' + 10);
	else {
	(*ndo->ndo_error)(ndo, "invalid hex digit %c in espsecret\n", hex);
	return 0;
	}
	}

	static u_int hex2byte(netdissect_options ndo, char hexstring)
	{
	u_int byte;

	byte = (hexdigit(ndo, hexstring[0]) << 4) + hexdigit(ndo, hexstring[1]);
	return byte;
	}

	/*
	* returns size of binary, 0 on failure.
	*/
	static
	int espprint_decode_hex(netdissect_options *ndo,
	u_char *binbuf, unsigned int binbuf_len,
	char *hex)
	{
	unsigned int len;
	int i;

	len = strlen(hex) / 2;

	if (len > binbuf_len) {
	(*ndo->ndo_warning)(ndo, "secret is too big: %d\n", len);
	return 0;
	}

	i = 0;
	while (hex[0] != '\0' && hex[1]!='\0') {
	binbuf[i] = hex2byte(ndo, hex);
	hex += 2;
	i++;
	}

	return i;
	}

	/*
	* decode the form: SPINUM@IP <tab> ALGONAME:0xsecret
	*/

	static int
	espprint_decode_encalgo(netdissect_options *ndo,
	char decode, struct sa_list sa)
	{
	int len;
	size_t i;
	const EVP_CIPHER *evp;
	int authlen = 0;
	char colon, p;

	colon = strchr(decode, ':');
	if (colon == NULL) {
	(*ndo->ndo_warning)(ndo, "failed to decode espsecret: %s\n", decode);
	return 0;
	}
	*colon = '\0';

	len = colon - decode;
	if (strlen(decode) > strlen("-hmac96") &&
	!strcmp(decode + strlen(decode) - strlen("-hmac96"),
	"-hmac96")) {
	p = strstr(decode, "-hmac96");
	*p = '\0';
	authlen = 12;
	}
	if (strlen(decode) > strlen("-cbc") &&
	!strcmp(decode + strlen(decode) - strlen("-cbc"), "-cbc")) {
	p = strstr(decode, "-cbc");
	*p = '\0';
	}
	evp = EVP_get_cipherbyname(decode);

	if (!evp) {
	(*ndo->ndo_warning)(ndo, "failed to find cipher algo %s\n", decode);
	sa->evp = NULL;
	sa->authlen = 0;
	sa->ivlen = 0;
	return 0;
	}

	sa->evp = evp;
	sa->authlen = authlen;
	sa->ivlen = EVP_CIPHER_iv_length(evp);

	colon++;
	if (colon[0] == '0' && colon[1] == 'x') {
	/* decode some hex! */

	colon += 2;
	sa->secretlen = espprint_decode_hex(ndo, sa->secret, sizeof(sa->secret), colon);
	if(sa->secretlen == 0) return 0;
	} else {
	i = strlen(colon);

	if (i < sizeof(sa->secret)) {
	memcpy(sa->secret, colon, i);
	sa->secretlen = i;
	} else {
	memcpy(sa->secret, colon, sizeof(sa->secret));
	sa->secretlen = sizeof(sa->secret);
	}
	}

	return 1;
	}

	/*
	* for the moment, ignore the auth algorith, just hard code the authenticator
	* length. Need to research how openssl looks up HMAC stuff.
	*/
	static int
	espprint_decode_authalgo(netdissect_options *ndo,
	char decode, struct sa_list sa)
	{
	char *colon;

	colon = strchr(decode, ':');
	if (colon == NULL) {
	(*ndo->ndo_warning)(ndo, "failed to decode espsecret: %s\n", decode);
	return 0;
	}
	*colon = '\0';

	if(strcasecmp(colon,"sha1") == 0 \|\|
	strcasecmp(colon,"md5") == 0) {
	sa->authlen = 12;
	}
	return 1;
	}

	static void esp_print_decode_ikeline(netdissect_options ndo, char line,
	const char *file, int lineno)
	{
	/* it's an IKEv2 secret, store it instead */
	struct sa_list sa1;

	char *init;
	char icookie, rcookie;
	int ilen, rlen;
	char *authkey;
	char *enckey;

	init = strsep(&line, " \t");
	icookie = strsep(&line, " \t");
	rcookie = strsep(&line, " \t");
	authkey = strsep(&line, " \t");
	enckey = strsep(&line, " \t");

	/* if any fields are missing */
	if(!init \|\| !icookie \|\| !rcookie \|\| !authkey \|\| !enckey) {
	(*ndo->ndo_warning)(ndo, "print_esp: failed to find all fields for ikev2 at %s:%u",
	file, lineno);

	return;
	}

	ilen = strlen(icookie);
	rlen = strlen(rcookie);

	if((init[0]!='I' && init[0]!='R')
	\|\| icookie[0]!='0' \|\| icookie[1]!='x'
	\|\| rcookie[0]!='0' \|\| rcookie[1]!='x'
	\|\| ilen!=18
	\|\| rlen!=18) {
	(*ndo->ndo_warning)(ndo, "print_esp: line %s:%u improperly formatted.",
	file, lineno);

	(*ndo->ndo_warning)(ndo, "init=%s icookie=%s(%u) rcookie=%s(%u)",
	init, icookie, ilen, rcookie, rlen);

	return;
	}

	sa1.spi = 0;
	sa1.initiator = (init[0] == 'I');
	if(espprint_decode_hex(ndo, sa1.spii, sizeof(sa1.spii), icookie+2)!=8)
	return;

	if(espprint_decode_hex(ndo, sa1.spir, sizeof(sa1.spir), rcookie+2)!=8)
	return;

	if(!espprint_decode_encalgo(ndo, enckey, &sa1)) return;

	if(!espprint_decode_authalgo(ndo, authkey, &sa1)) return;

	esp_print_addsa(ndo, &sa1, FALSE);
	}

	/*
	*
	* special form: file /name
	* causes us to go read from this file instead.
	*
	*/
	static void esp_print_decode_onesecret(netdissect_options ndo, char line,
	const char *file, int lineno)
	{
	struct sa_list sa1;
	int sa_def;

	char *spikey;
	char *decode;

	spikey = strsep(&line, " \t");
	sa_def = 0;
	memset(&sa1, 0, sizeof(struct sa_list));

	/* if there is only one token, then it is an algo:key token */
	if (line == NULL) {
	decode = spikey;
	spikey = NULL;
	/* memset(&sa1.daddr, 0, sizeof(sa1.daddr)); */
	/* sa1.spi = 0; */
	sa_def = 1;
	} else
	decode = line;

	if (spikey && strcasecmp(spikey, "file") == 0) {
	/* open file and read it */
	FILE *secretfile;
	char fileline[1024];
	int lineno=0;
	char *nl;
	char *filename = line;

	secretfile = fopen(filename, FOPEN_READ_TXT);
	if (secretfile == NULL) {
	perror(filename);
	exit(3);
	}

	while (fgets(fileline, sizeof(fileline)-1, secretfile) != NULL) {
	lineno++;
	/* remove newline from the line */
	nl = strchr(fileline, '\n');
	if (nl)
	*nl = '\0';
	if (fileline[0] == '#') continue;
	if (fileline[0] == '\0') continue;

	esp_print_decode_onesecret(ndo, fileline, filename, lineno);
	}
	fclose(secretfile);

	return;
	}

	if (spikey && strcasecmp(spikey, "ikev2") == 0) {
	esp_print_decode_ikeline(ndo, line, file, lineno);
	return;
	}

	if (spikey) {

	char spistr, foo;
	u_int32_t spino;
	struct sockaddr_in *sin;
	#ifdef INET6
	struct sockaddr_in6 *sin6;
	#endif

	spistr = strsep(&spikey, "@");

	spino = strtoul(spistr, &foo, 0);
	if (spistr == foo \|\| !spikey) {
	(*ndo->ndo_warning)(ndo, "print_esp: failed to decode spi# %s\n", foo);
	return;
	}

	sa1.spi = spino;

	sin = (struct sockaddr_in *)&sa1.daddr;
	#ifdef INET6
	sin6 = (struct sockaddr_in6 *)&sa1.daddr;
	if (inet_pton(AF_INET6, spikey, &sin6->sin6_addr) == 1) {
	#ifdef HAVE_SOCKADDR_SA_LEN
	sin6->sin6_len = sizeof(struct sockaddr_in6);
	#endif
	sin6->sin6_family = AF_INET6;
	} else
	#endif
	if (inet_pton(AF_INET, spikey, &sin->sin_addr) == 1) {
	#ifdef HAVE_SOCKADDR_SA_LEN
	sin->sin_len = sizeof(struct sockaddr_in);
	#endif
	sin->sin_family = AF_INET;
	} else {
	(*ndo->ndo_warning)(ndo, "print_esp: can not decode IP# %s\n", spikey);
	return;
	}
	}

	if (decode) {
	/* skip any blank spaces */
	while (isspace((unsigned char)*decode))
	decode++;

	if(!espprint_decode_encalgo(ndo, decode, &sa1)) {
	return;
	}
	}

	esp_print_addsa(ndo, &sa1, sa_def);
	}

	static void esp_init(netdissect_options *ndo _U_)
	{

	OpenSSL_add_all_algorithms();
	EVP_add_cipher_alias(SN_des_ede3_cbc, "3des");
	}

	void esp_print_decodesecret(netdissect_options *ndo)
	{
	char *line;
	char *p;
	static int initialized = 0;

	if (!initialized) {
	esp_init(ndo);
	initialized = 1;
	}

	p = ndo->ndo_espsecret;

	while (p && p[0] != '\0') {
	/* pick out the first line or first thing until a comma */
	if ((line = strsep(&p, "\n,")) == NULL) {
	line = p;
	p = NULL;
	}

	esp_print_decode_onesecret(ndo, line, "cmdline", 0);
	}

	ndo->ndo_espsecret = NULL;
	}

	#endif

	int
	esp_print(netdissect_options *ndo,
	const u_char bp, const int length, const u_char bp2
	#ifndef HAVE_LIBCRYPTO
	_U_
	#endif
	,
	int *nhdr
	#ifndef HAVE_LIBCRYPTO
	_U_
	#endif
	,
	int *padlen
	#ifndef HAVE_LIBCRYPTO
	_U_
	#endif
	)
	{
	register const struct newesp *esp;
	register const u_char *ep;
	#ifdef HAVE_LIBCRYPTO
	struct ip *ip;
	struct sa_list *sa = NULL;
	int espsecret_keylen;
	#ifdef INET6
	struct ip6_hdr *ip6 = NULL;
	#endif
	int advance;
	int len;
	u_char *secret;
	int ivlen = 0;
	u_char *ivoff;
	u_char *p;
	EVP_CIPHER_CTX ctx;
	int blocksz;
	#endif

	esp = (struct newesp *)bp;

	#ifdef HAVE_LIBCRYPTO
	secret = NULL;
	advance = 0;
	#endif

	#if 0
	/* keep secret out of a register */
	p = (u_char *)&secret;
	#endif

	/* 'ep' points to the end of available data. */
	ep = ndo->ndo_snapend;

	if ((u_char *)(esp + 1) >= ep) {
	fputs("[\|ESP]", stdout);
	goto fail;
	}
	(*ndo->ndo_printf)(ndo, "ESP(spi=0x%08x", EXTRACT_32BITS(&esp->esp_spi));
	(*ndo->ndo_printf)(ndo, ",seq=0x%x)", EXTRACT_32BITS(&esp->esp_seq));
	(*ndo->ndo_printf)(ndo, ", length %u", length);

	#ifndef HAVE_LIBCRYPTO
	goto fail;
	#else
	/* initiailize SAs */
	if (ndo->ndo_sa_list_head == NULL) {
	if (!ndo->ndo_espsecret)
	goto fail;

	esp_print_decodesecret(ndo);
	}

	if (ndo->ndo_sa_list_head == NULL)
	goto fail;

	ip = (struct ip *)bp2;
	switch (IP_V(ip)) {
	#ifdef INET6
	case 6:
	ip6 = (struct ip6_hdr *)bp2;
	/* we do not attempt to decrypt jumbograms */
	if (!EXTRACT_16BITS(&ip6->ip6_plen))
	goto fail;
	/* if we can't get nexthdr, we do not need to decrypt it */
	len = sizeof(struct ip6_hdr) + EXTRACT_16BITS(&ip6->ip6_plen);

	/* see if we can find the SA, and if so, decode it */
	for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) {
	struct sockaddr_in6 sin6 = (struct sockaddr_in6 )&sa->daddr;
	if (sa->spi == EXTRACT_32BITS(&esp->esp_spi) &&
	sin6->sin6_family == AF_INET6 &&
	memcmp(&sin6->sin6_addr, &ip6->ip6_dst,
	sizeof(struct in6_addr)) == 0) {
	break;
	}
	}
	break;
	#endif /INET6/
	case 4:
	/* nexthdr & padding are in the last fragment */
	if (EXTRACT_16BITS(&ip->ip_off) & IP_MF)
	goto fail;
	len = EXTRACT_16BITS(&ip->ip_len);

	/* see if we can find the SA, and if so, decode it */
	for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) {
	struct sockaddr_in sin = (struct sockaddr_in )&sa->daddr;
	if (sa->spi == EXTRACT_32BITS(&esp->esp_spi) &&
	sin->sin_family == AF_INET &&
	sin->sin_addr.s_addr == ip->ip_dst.s_addr) {
	break;
	}
	}
	break;
	default:
	goto fail;
	}

	/* if we didn't find the specific one, then look for
	* an unspecified one.
	*/
	if (sa == NULL)
	sa = ndo->ndo_sa_default;

	/* if not found fail */
	if (sa == NULL)
	goto fail;

	/* if we can't get nexthdr, we do not need to decrypt it */
	if (ep - bp2 < len)
	goto fail;
	if (ep - bp2 > len) {
	/* FCS included at end of frame (NetBSD 1.6 or later) */
	ep = bp2 + len;
	}

	ivoff = (u_char *)(esp + 1) + 0;
	ivlen = sa->ivlen;
	secret = sa->secret;
	espsecret_keylen = sa->secretlen;
	ep = ep - sa->authlen;

	if (sa->evp) {
	memset(&ctx, 0, sizeof(ctx));
	if (EVP_CipherInit(&ctx, sa->evp, secret, NULL, 0) < 0)
	(*ndo->ndo_warning)(ndo, "espkey init failed");

	blocksz = EVP_CIPHER_CTX_block_size(&ctx);

	p = ivoff;
	EVP_CipherInit(&ctx, NULL, NULL, p, 0);
	EVP_Cipher(&ctx, p + ivlen, p + ivlen, ep - (p + ivlen));
	EVP_CIPHER_CTX_cleanup(&ctx);
	advance = ivoff - (u_char *)esp + ivlen;
	} else
	advance = sizeof(struct newesp);

	/* sanity check for pad length */
	if (ep - bp < *(ep - 2))
	goto fail;

	if (padlen)
	padlen = (ep - 2) + 2;

	if (nhdr)
	nhdr = (ep - 1);

	(ndo->ndo_printf)(ndo, ": ");
	return advance;
	#endif

	fail:
	return -1;
	}

	/*
	* Local Variables:
	* c-style: whitesmith
	* c-basic-offset: 8
	* End:
	*/