/* $OpenBSD: s_cb.c,v 1.1 2014/08/26 17:47:25 jsing Exp $ */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */
/* ====================================================================
 * Copyright (c) 1998-2006 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    openssl-core@openssl.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#include <sys/socket.h>

#include <netinet/in.h>

#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "apps.h"

#include <openssl/err.h>
#include <openssl/ssl.h>
#include <openssl/x509.h>

#include "s_apps.h"

#define	COOKIE_SECRET_LENGTH	16

int verify_depth = 0;
int verify_error = X509_V_OK;
int verify_return_error = 0;
unsigned char cookie_secret[COOKIE_SECRET_LENGTH];
int cookie_initialized = 0;

int
verify_callback(int ok, X509_STORE_CTX * ctx)
{
	X509 *err_cert;
	int err, depth;

	err_cert = X509_STORE_CTX_get_current_cert(ctx);
	err = X509_STORE_CTX_get_error(ctx);
	depth = X509_STORE_CTX_get_error_depth(ctx);

	BIO_printf(bio_err, "depth=%d ", depth);
	if (err_cert) {
		X509_NAME_print_ex(bio_err, X509_get_subject_name(err_cert),
		    0, XN_FLAG_ONELINE);
		BIO_puts(bio_err, "\n");
	} else
		BIO_puts(bio_err, "<no cert>\n");
	if (!ok) {
		BIO_printf(bio_err, "verify error:num=%d:%s\n", err,
		    X509_verify_cert_error_string(err));
		if (verify_depth >= depth) {
			if (!verify_return_error)
				ok = 1;
			verify_error = X509_V_OK;
		} else {
			ok = 0;
			verify_error = X509_V_ERR_CERT_CHAIN_TOO_LONG;
		}
	}
	switch (err) {
	case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT:
		BIO_puts(bio_err, "issuer= ");
		X509_NAME_print_ex(bio_err, X509_get_issuer_name(err_cert),
		    0, XN_FLAG_ONELINE);
		BIO_puts(bio_err, "\n");
		break;
	case X509_V_ERR_CERT_NOT_YET_VALID:
	case X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD:
		BIO_printf(bio_err, "notBefore=");
		ASN1_TIME_print(bio_err, X509_get_notBefore(err_cert));
		BIO_printf(bio_err, "\n");
		break;
	case X509_V_ERR_CERT_HAS_EXPIRED:
	case X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD:
		BIO_printf(bio_err, "notAfter=");
		ASN1_TIME_print(bio_err, X509_get_notAfter(err_cert));
		BIO_printf(bio_err, "\n");
		break;
	case X509_V_ERR_NO_EXPLICIT_POLICY:
		policies_print(bio_err, ctx);
		break;
	}
	if (err == X509_V_OK && ok == 2)
		policies_print(bio_err, ctx);

	BIO_printf(bio_err, "verify return:%d\n", ok);
	return (ok);
}

int
set_cert_stuff(SSL_CTX * ctx, char *cert_file, char *key_file)
{
	if (cert_file != NULL) {
		/*
		SSL *ssl;
		X509 *x509;
		*/

		if (SSL_CTX_use_certificate_file(ctx, cert_file,
		    SSL_FILETYPE_PEM) <= 0) {
			BIO_printf(bio_err,
			    "unable to get certificate from '%s'\n", cert_file);
			ERR_print_errors(bio_err);
			return (0);
		}
		if (key_file == NULL)
			key_file = cert_file;
		if (SSL_CTX_use_PrivateKey_file(ctx, key_file,
		    SSL_FILETYPE_PEM) <= 0) {
			BIO_printf(bio_err,
			    "unable to get private key from '%s'\n", key_file);
			ERR_print_errors(bio_err);
			return (0);
		}
		/*
		In theory this is no longer needed
		ssl=SSL_new(ctx);
		x509=SSL_get_certificate(ssl);

		if (x509 != NULL) {
			EVP_PKEY *pktmp;
			pktmp = X509_get_pubkey(x509);
			EVP_PKEY_copy_parameters(pktmp,
						SSL_get_privatekey(ssl));
			EVP_PKEY_free(pktmp);
		}
		SSL_free(ssl);
		*/

		/*
		 * If we are using DSA, we can copy the parameters from the
		 * private key
		 */


		/*
		 * Now we know that a key and cert have been set against the
		 * SSL context
		 */
		if (!SSL_CTX_check_private_key(ctx)) {
			BIO_printf(bio_err,
			    "Private key does not match the certificate public key\n");
			return (0);
		}
	}
	return (1);
}

int
set_cert_key_stuff(SSL_CTX * ctx, X509 * cert, EVP_PKEY * key)
{
	if (cert == NULL)
		return 1;
	if (SSL_CTX_use_certificate(ctx, cert) <= 0) {
		BIO_printf(bio_err, "error setting certificate\n");
		ERR_print_errors(bio_err);
		return 0;
	}
	if (SSL_CTX_use_PrivateKey(ctx, key) <= 0) {
		BIO_printf(bio_err, "error setting private key\n");
		ERR_print_errors(bio_err);
		return 0;
	}
	/*
	 * Now we know that a key and cert have been set against the SSL
	 * context
	 */
	if (!SSL_CTX_check_private_key(ctx)) {
		BIO_printf(bio_err,
		    "Private key does not match the certificate public key\n");
		return 0;
	}
	return 1;
}

long
bio_dump_callback(BIO * bio, int cmd, const char *argp,
    int argi, long argl, long ret)
{
	BIO *out;

	out = (BIO *) BIO_get_callback_arg(bio);
	if (out == NULL)
		return (ret);

	if (cmd == (BIO_CB_READ | BIO_CB_RETURN)) {
		BIO_printf(out,
		    "read from %p [%p] (%lu bytes => %ld (0x%lX))\n",
		    (void *) bio, argp, (unsigned long) argi, ret, ret);
		BIO_dump(out, argp, (int) ret);
		return (ret);
	} else if (cmd == (BIO_CB_WRITE | BIO_CB_RETURN)) {
		BIO_printf(out,
		    "write to %p [%p] (%lu bytes => %ld (0x%lX))\n",
		    (void *) bio, argp, (unsigned long) argi, ret, ret);
		BIO_dump(out, argp, (int) ret);
	}
	return (ret);
}

void
apps_ssl_info_callback(const SSL * s, int where, int ret)
{
	const char *str;
	int w;

	w = where & ~SSL_ST_MASK;

	if (w & SSL_ST_CONNECT)
		str = "SSL_connect";
	else if (w & SSL_ST_ACCEPT)
		str = "SSL_accept";
	else
		str = "undefined";

	if (where & SSL_CB_LOOP) {
		BIO_printf(bio_err, "%s:%s\n", str, SSL_state_string_long(s));
	} else if (where & SSL_CB_ALERT) {
		str = (where & SSL_CB_READ) ? "read" : "write";
		BIO_printf(bio_err, "SSL3 alert %s:%s:%s\n", str,
		    SSL_alert_type_string_long(ret),
		    SSL_alert_desc_string_long(ret));
	} else if (where & SSL_CB_EXIT) {
		if (ret == 0)
			BIO_printf(bio_err, "%s:failed in %s\n",
			    str, SSL_state_string_long(s));
		else if (ret < 0) {
			BIO_printf(bio_err, "%s:error in %s\n",
			    str, SSL_state_string_long(s));
		}
	}
}


void
msg_cb(int write_p, int version, int content_type, const void *buf, size_t len, SSL * ssl, void *arg)
{
	BIO *bio = arg;
	const char *str_write_p, *str_version, *str_content_type = "",
	    *str_details1 = "", *str_details2 = "";

	str_write_p = write_p ? ">>>" : "<<<";

	switch (version) {
	case SSL2_VERSION:
		str_version = "SSL 2.0";
		break;
	case SSL3_VERSION:
		str_version = "SSL 3.0 ";
		break;
	case TLS1_VERSION:
		str_version = "TLS 1.0 ";
		break;
	case TLS1_1_VERSION:
		str_version = "TLS 1.1 ";
		break;
	case TLS1_2_VERSION:
		str_version = "TLS 1.2 ";
		break;
	case DTLS1_VERSION:
		str_version = "DTLS 1.0 ";
		break;
	case DTLS1_BAD_VER:
		str_version = "DTLS 1.0 (bad) ";
		break;
	default:
		str_version = "???";
	}

	if (version == SSL2_VERSION) {
		str_details1 = "???";

		if (len > 0) {
			switch (((const unsigned char *) buf)[0]) {
			case 0:
				str_details1 = ", ERROR:";
				str_details2 = " ???";
				if (len >= 3) {
					unsigned err = (((const unsigned char *) buf)[1] << 8) + ((const unsigned char *) buf)[2];

					switch (err) {
					case 0x0001:
						str_details2 = " NO-CIPHER-ERROR";
						break;
					case 0x0002:
						str_details2 = " NO-CERTIFICATE-ERROR";
						break;
					case 0x0004:
						str_details2 = " BAD-CERTIFICATE-ERROR";
						break;
					case 0x0006:
						str_details2 = " UNSUPPORTED-CERTIFICATE-TYPE-ERROR";
						break;
					}
				}
				break;
			case 1:
				str_details1 = ", CLIENT-HELLO";
				break;
			case 2:
				str_details1 = ", CLIENT-MASTER-KEY";
				break;
			case 3:
				str_details1 = ", CLIENT-FINISHED";
				break;
			case 4:
				str_details1 = ", SERVER-HELLO";
				break;
			case 5:
				str_details1 = ", SERVER-VERIFY";
				break;
			case 6:
				str_details1 = ", SERVER-FINISHED";
				break;
			case 7:
				str_details1 = ", REQUEST-CERTIFICATE";
				break;
			case 8:
				str_details1 = ", CLIENT-CERTIFICATE";
				break;
			}
		}
	}
	if (version == SSL3_VERSION || version == TLS1_VERSION ||
	    version == TLS1_1_VERSION || version == TLS1_2_VERSION ||
	    version == DTLS1_VERSION || version == DTLS1_BAD_VER) {
		switch (content_type) {
		case 20:
			str_content_type = "ChangeCipherSpec";
			break;
		case 21:
			str_content_type = "Alert";
			break;
		case 22:
			str_content_type = "Handshake";
			break;
		}

		if (content_type == 21) {	/* Alert */
			str_details1 = ", ???";

			if (len == 2) {
				switch (((const unsigned char *) buf)[0]) {
				case 1:
					str_details1 = ", warning";
					break;
				case 2:
					str_details1 = ", fatal";
					break;
				}

				str_details2 = " ???";
				switch (((const unsigned char *) buf)[1]) {
				case 0:
					str_details2 = " close_notify";
					break;
				case 10:
					str_details2 = " unexpected_message";
					break;
				case 20:
					str_details2 = " bad_record_mac";
					break;
				case 21:
					str_details2 = " decryption_failed";
					break;
				case 22:
					str_details2 = " record_overflow";
					break;
				case 30:
					str_details2 = " decompression_failure";
					break;
				case 40:
					str_details2 = " handshake_failure";
					break;
				case 42:
					str_details2 = " bad_certificate";
					break;
				case 43:
					str_details2 = " unsupported_certificate";
					break;
				case 44:
					str_details2 = " certificate_revoked";
					break;
				case 45:
					str_details2 = " certificate_expired";
					break;
				case 46:
					str_details2 = " certificate_unknown";
					break;
				case 47:
					str_details2 = " illegal_parameter";
					break;
				case 48:
					str_details2 = " unknown_ca";
					break;
				case 49:
					str_details2 = " access_denied";
					break;
				case 50:
					str_details2 = " decode_error";
					break;
				case 51:
					str_details2 = " decrypt_error";
					break;
				case 60:
					str_details2 = " export_restriction";
					break;
				case 70:
					str_details2 = " protocol_version";
					break;
				case 71:
					str_details2 = " insufficient_security";
					break;
				case 80:
					str_details2 = " internal_error";
					break;
				case 90:
					str_details2 = " user_canceled";
					break;
				case 100:
					str_details2 = " no_renegotiation";
					break;
				case 110:
					str_details2 = " unsupported_extension";
					break;
				case 111:
					str_details2 = " certificate_unobtainable";
					break;
				case 112:
					str_details2 = " unrecognized_name";
					break;
				case 113:
					str_details2 = " bad_certificate_status_response";
					break;
				case 114:
					str_details2 = " bad_certificate_hash_value";
					break;
				case 115:
					str_details2 = " unknown_psk_identity";
					break;
				}
			}
		}
		if (content_type == 22) {	/* Handshake */
			str_details1 = "???";

			if (len > 0) {
				switch (((const unsigned char *) buf)[0]) {
				case 0:
					str_details1 = ", HelloRequest";
					break;
				case 1:
					str_details1 = ", ClientHello";
					break;
				case 2:
					str_details1 = ", ServerHello";
					break;
				case 3:
					str_details1 = ", HelloVerifyRequest";
					break;
				case 11:
					str_details1 = ", Certificate";
					break;
				case 12:
					str_details1 = ", ServerKeyExchange";
					break;
				case 13:
					str_details1 = ", CertificateRequest";
					break;
				case 14:
					str_details1 = ", ServerHelloDone";
					break;
				case 15:
					str_details1 = ", CertificateVerify";
					break;
				case 16:
					str_details1 = ", ClientKeyExchange";
					break;
				case 20:
					str_details1 = ", Finished";
					break;
				}
			}
		}
	}
	BIO_printf(bio, "%s %s%s [length %04lx]%s%s\n", str_write_p,
	    str_version, str_content_type, (unsigned long) len,
	    str_details1, str_details2);

	if (len > 0) {
		size_t num, i;

		BIO_printf(bio, "   ");
		num = len;
#if 0
		if (num > 16)
			num = 16;
#endif
		for (i = 0; i < num; i++) {
			if (i % 16 == 0 && i > 0)
				BIO_printf(bio, "\n   ");
			BIO_printf(bio, " %02x",
			    ((const unsigned char *) buf)[i]);
		}
		if (i < len)
			BIO_printf(bio, " ...");
		BIO_printf(bio, "\n");
	}
	(void) BIO_flush(bio);
}

void
tlsext_cb(SSL * s, int client_server, int type, unsigned char *data, int len,
    void *arg)
{
	BIO *bio = arg;
	char *extname;

	switch (type) {
	case TLSEXT_TYPE_server_name:
		extname = "server name";
		break;

	case TLSEXT_TYPE_max_fragment_length:
		extname = "max fragment length";
		break;

	case TLSEXT_TYPE_client_certificate_url:
		extname = "client certificate URL";
		break;

	case TLSEXT_TYPE_trusted_ca_keys:
		extname = "trusted CA keys";
		break;

	case TLSEXT_TYPE_truncated_hmac:
		extname = "truncated HMAC";
		break;

	case TLSEXT_TYPE_status_request:
		extname = "status request";
		break;

	case TLSEXT_TYPE_user_mapping:
		extname = "user mapping";
		break;

	case TLSEXT_TYPE_client_authz:
		extname = "client authz";
		break;

	case TLSEXT_TYPE_server_authz:
		extname = "server authz";
		break;

	case TLSEXT_TYPE_cert_type:
		extname = "cert type";
		break;

	case TLSEXT_TYPE_elliptic_curves:
		extname = "elliptic curves";
		break;

	case TLSEXT_TYPE_ec_point_formats:
		extname = "EC point formats";
		break;

	case TLSEXT_TYPE_srp:
		extname = "SRP";
		break;

	case TLSEXT_TYPE_signature_algorithms:
		extname = "signature algorithms";
		break;

	case TLSEXT_TYPE_use_srtp:
		extname = "use SRTP";
		break;

	case TLSEXT_TYPE_heartbeat:
		extname = "heartbeat";
		break;

	case TLSEXT_TYPE_session_ticket:
		extname = "session ticket";
		break;

	case TLSEXT_TYPE_renegotiate:
		extname = "renegotiation info";
		break;

#ifdef TLSEXT_TYPE_next_proto_neg
	case TLSEXT_TYPE_next_proto_neg:
		extname = "next protocol";
		break;
#endif

	default:
		extname = "unknown";
		break;

	}

	BIO_printf(bio, "TLS %s extension \"%s\" (id=%d), len=%d\n",
	    client_server ? "server" : "client", extname, type, len);
	BIO_dump(bio, (char *) data, len);
	(void) BIO_flush(bio);
}

int
generate_cookie_callback(SSL * ssl, unsigned char *cookie,
    unsigned int *cookie_len)
{
	unsigned char *buffer, result[EVP_MAX_MD_SIZE];
	unsigned int length, resultlength;
	union {
		struct sockaddr sa;
		struct sockaddr_in s4;
		struct sockaddr_in6 s6;
	} peer;

	/* Initialize a random secret */
	if (!cookie_initialized) {
		arc4random_buf(cookie_secret, COOKIE_SECRET_LENGTH);
		cookie_initialized = 1;
	}
	/* Read peer information */
	(void) BIO_dgram_get_peer(SSL_get_rbio(ssl), &peer);

	/* Create buffer with peer's address and port */
	length = 0;
	switch (peer.sa.sa_family) {
	case AF_INET:
		length += sizeof(struct in_addr);
		length += sizeof(peer.s4.sin_port);
		break;
	case AF_INET6:
		length += sizeof(struct in6_addr);
		length += sizeof(peer.s6.sin6_port);
		break;
	default:
		OPENSSL_assert(0);
		break;
	}
	buffer = malloc(length);

	if (buffer == NULL) {
		BIO_printf(bio_err, "out of memory\n");
		return 0;
	}
	switch (peer.sa.sa_family) {
	case AF_INET:
		memcpy(buffer, &peer.s4.sin_port, sizeof(peer.s4.sin_port));
		memcpy(buffer + sizeof(peer.s4.sin_port),
		    &peer.s4.sin_addr, sizeof(struct in_addr));
		break;
	case AF_INET6:
		memcpy(buffer, &peer.s6.sin6_port, sizeof(peer.s6.sin6_port));
		memcpy(buffer + sizeof(peer.s6.sin6_port),
		    &peer.s6.sin6_addr, sizeof(struct in6_addr));
		break;
	default:
		OPENSSL_assert(0);
		break;
	}

	/* Calculate HMAC of buffer using the secret */
	HMAC(EVP_sha1(), cookie_secret, COOKIE_SECRET_LENGTH,
	    buffer, length, result, &resultlength);
	free(buffer);

	memcpy(cookie, result, resultlength);
	*cookie_len = resultlength;

	return 1;
}

int
verify_cookie_callback(SSL * ssl, unsigned char *cookie, unsigned int cookie_len)
{
	unsigned char *buffer, result[EVP_MAX_MD_SIZE];
	unsigned int length, resultlength;
	union {
		struct sockaddr sa;
		struct sockaddr_in s4;
		struct sockaddr_in6 s6;
	} peer;

	/* If secret isn't initialized yet, the cookie can't be valid */
	if (!cookie_initialized)
		return 0;

	/* Read peer information */
	(void) BIO_dgram_get_peer(SSL_get_rbio(ssl), &peer);

	/* Create buffer with peer's address and port */
	length = 0;
	switch (peer.sa.sa_family) {
	case AF_INET:
		length += sizeof(struct in_addr);
		length += sizeof(peer.s4.sin_port);
		break;
	case AF_INET6:
		length += sizeof(struct in6_addr);
		length += sizeof(peer.s6.sin6_port);
		break;
	default:
		OPENSSL_assert(0);
		break;
	}
	buffer = malloc(length);

	if (buffer == NULL) {
		BIO_printf(bio_err, "out of memory\n");
		return 0;
	}
	switch (peer.sa.sa_family) {
	case AF_INET:
		memcpy(buffer, &peer.s4.sin_port, sizeof(peer.s4.sin_port));
		memcpy(buffer + sizeof(peer.s4.sin_port),
		    &peer.s4.sin_addr, sizeof(struct in_addr));
		break;
	case AF_INET6:
		memcpy(buffer, &peer.s6.sin6_port, sizeof(peer.s6.sin6_port));
		memcpy(buffer + sizeof(peer.s6.sin6_port),
		    &peer.s6.sin6_addr, sizeof(struct in6_addr));
		break;
	default:
		OPENSSL_assert(0);
		break;
	}

	/* Calculate HMAC of buffer using the secret */
	HMAC(EVP_sha1(), cookie_secret, COOKIE_SECRET_LENGTH,
	    buffer, length, result, &resultlength);
	free(buffer);

	if (cookie_len == resultlength &&
	    memcmp(result, cookie, resultlength) == 0)
		return 1;

	return 0;
}
