pppd/plugins/radius/sendserver.c - platform/external/ppp - Git at Google

 /*
  * $Id: sendserver.c,v 1.1 2004/11/14 07:26:26 paulus Exp $
  *
  * Copyright (C) 1995,1996,1997 Lars Fenneberg
  *
  * Copyright 1992 Livingston Enterprises, Inc.
  *
  * Copyright 1992,1993, 1994,1995 The Regents of the University of Michigan
  * and Merit Network, Inc. All Rights Reserved
  *
  * See the file COPYRIGHT for the respective terms and conditions.
  * If the file is missing contact me at lf@elemental.net
  * and I'll send you a copy.
  *
  */

 #include <includes.h>
 #include <radiusclient.h>
 #include <pathnames.h>

 static void rc_random_vector (unsigned char *);
 static int rc_check_reply (AUTH_HDR *, int, char *, unsigned char *, unsigned char);

 /*
  * Function: rc_pack_list
  *
  * Purpose: Packs an attribute value pair list into a buffer.
  *
  * Returns: Number of octets packed.
  *
  */

 static int rc_pack_list (VALUE_PAIR *vp, char *secret, AUTH_HDR *auth)
 {
     int             length, i, pc, secretlen, padded_length;
     int             total_length = 0;
     UINT4           lvalue;
     unsigned char   passbuf[MAX(AUTH_PASS_LEN, CHAP_VALUE_LENGTH)];
     unsigned char   md5buf[256];
     unsigned char   *buf, *vector, *lenptr;

     buf = auth->data;

     while (vp != (VALUE_PAIR *) NULL)
 	{

 	    if (vp->vendorcode != VENDOR_NONE) {
 		*buf++ = PW_VENDOR_SPECIFIC;

 		/* Place-holder for where to put length */
 		lenptr = buf++;

 		/* Insert vendor code */
 		*buf++ = 0;
 		*buf++ = (((unsigned int) vp->vendorcode) >> 16) & 255;
 		*buf++ = (((unsigned int) vp->vendorcode) >> 8) & 255;
 		*buf++ = ((unsigned int) vp->vendorcode) & 255;

 		/* Insert vendor-type */
 		*buf++ = vp->attribute;

 		/* Insert value */
 		switch(vp->type) {
 		case PW_TYPE_STRING:
 		    length = vp->lvalue;
 		    *lenptr = length + 8;
 		    *buf++ = length+2;
 		    memcpy(buf, vp->strvalue, (size_t) length);
 		    buf += length;
 		    total_length += length+8;
 		    break;
 		case PW_TYPE_INTEGER:
 		case PW_TYPE_IPADDR:
 		    length = sizeof(UINT4);
 		    *lenptr = length + 8;
 		    *buf++ = length+2;
 		    lvalue = htonl(vp->lvalue);
 		    memcpy(buf, (char *) &lvalue, sizeof(UINT4));
 		    buf += length;
 		    total_length += length+8;
 		    break;
 		default:
 		    break;
 		}
 	    } else {
 		*buf++ = vp->attribute;
 		switch (vp->attribute) {
 		case PW_USER_PASSWORD:

 		    /* Encrypt the password */

 		    /* Chop off password at AUTH_PASS_LEN */
 		    length = vp->lvalue;
 		    if (length > AUTH_PASS_LEN) length = AUTH_PASS_LEN;

 		    /* Calculate the padded length */
 		    padded_length = (length+(AUTH_VECTOR_LEN-1)) & ~(AUTH_VECTOR_LEN-1);

 		    /* Record the attribute length */
 		    *buf++ = padded_length + 2;

 		    /* Pad the password with zeros */
 		    memset ((char *) passbuf, '\0', AUTH_PASS_LEN);
 		    memcpy ((char *) passbuf, vp->strvalue, (size_t) length);

 		    secretlen = strlen (secret);
 		    vector = (char *)auth->vector;
 		    for(i = 0; i < padded_length; i += AUTH_VECTOR_LEN) {
 			/* Calculate the MD5 digest*/
 			strcpy ((char *) md5buf, secret);
 			memcpy ((char *) md5buf + secretlen, vector,
 				AUTH_VECTOR_LEN);
 			rc_md5_calc (buf, md5buf, secretlen + AUTH_VECTOR_LEN);

 			/* Remeber the start of the digest */
 			vector = buf;

 			/* Xor the password into the MD5 digest */
 			for (pc = i; pc < (i + AUTH_VECTOR_LEN); pc++) {
 			    *buf++ ^= passbuf[pc];
 			}
 		    }

 		    total_length += padded_length + 2;

 		    break;
 #if 0
 		case PW_CHAP_PASSWORD:

 		    *buf++ = CHAP_VALUE_LENGTH + 2;

 		    /* Encrypt the Password */
 		    length = vp->lvalue;
 		    if (length > CHAP_VALUE_LENGTH) {
 			length = CHAP_VALUE_LENGTH;
 		    }
 		    memset ((char *) passbuf, '\0', CHAP_VALUE_LENGTH);
 		    memcpy ((char *) passbuf, vp->strvalue, (size_t) length);

 		    /* Calculate the MD5 Digest */
 		    secretlen = strlen (secret);
 		    strcpy ((char *) md5buf, secret);
 		    memcpy ((char *) md5buf + secretlen, (char *) auth->vector,
 			    AUTH_VECTOR_LEN);
 		    rc_md5_calc (buf, md5buf, secretlen + AUTH_VECTOR_LEN);

 		    /* Xor the password into the MD5 digest */
 		    for (i = 0; i < CHAP_VALUE_LENGTH; i++) {
 			*buf++ ^= passbuf[i];
 		    }
 		    total_length += CHAP_VALUE_LENGTH + 2;

 		    break;
 #endif
 		default:
 		    switch (vp->type) {
 		    case PW_TYPE_STRING:
 			length = vp->lvalue;
 			*buf++ = length + 2;
 			memcpy (buf, vp->strvalue, (size_t) length);
 			buf += length;
 			total_length += length + 2;
 			break;

 		    case PW_TYPE_INTEGER:
 		    case PW_TYPE_IPADDR:
 			*buf++ = sizeof (UINT4) + 2;
 			lvalue = htonl (vp->lvalue);
 			memcpy (buf, (char *) &lvalue, sizeof (UINT4));
 			buf += sizeof (UINT4);
 			total_length += sizeof (UINT4) + 2;
 			break;

 		    default:
 			break;
 		    }
 		    break;
 		}
 	    }
 	    vp = vp->next;
 	}
     return total_length;
 }

 /*
  * Function: rc_send_server
  *
  * Purpose: send a request to a RADIUS server and wait for the reply
  *
  */

 int rc_send_server (SEND_DATA *data, char *msg, REQUEST_INFO *info)
 {
 	int             sockfd;
 	struct sockaddr salocal;
 	struct sockaddr saremote;
 	struct sockaddr_in *sin;
 	struct timeval  authtime;
 	fd_set          readfds;
 	AUTH_HDR       *auth, *recv_auth;
 	UINT4           auth_ipaddr;
 	char           *server_name;	/* Name of server to query */
 	int             salen;
 	int             result;
 	int             total_length;
 	int             length;
 	int             retry_max;
 	int		secretlen;
 	char            secret[MAX_SECRET_LENGTH + 1];
 	unsigned char   vector[AUTH_VECTOR_LEN];
 	char            recv_buffer[BUFFER_LEN];
 	char            send_buffer[BUFFER_LEN];
 	int		retries;
 	VALUE_PAIR	*vp;

 	server_name = data->server;
 	if (server_name == (char *) NULL || server_name[0] == '\0')
 		return (ERROR_RC);

 	if ((vp = rc_avpair_get(data->send_pairs, PW_SERVICE_TYPE)) && \
 	    (vp->lvalue == PW_ADMINISTRATIVE))
 	{
 		strcpy(secret, MGMT_POLL_SECRET);
 		if ((auth_ipaddr = rc_get_ipaddr(server_name)) == 0)
 			return (ERROR_RC);
 	}
 	else
 	{
 		if (rc_find_server (server_name, &auth_ipaddr, secret) != 0)
 		{
 			return (ERROR_RC);
 		}
 	}

 	sockfd = socket (AF_INET, SOCK_DGRAM, 0);
 	if (sockfd < 0)
 	{
 		memset (secret, '\0', sizeof (secret));
 		error("rc_send_server: socket: %s", strerror(errno));
 		return (ERROR_RC);
 	}

 	length = sizeof (salocal);
 	sin = (struct sockaddr_in *) & salocal;
 	memset ((char *) sin, '\0', (size_t) length);
 	sin->sin_family = AF_INET;
 	sin->sin_addr.s_addr = htonl(INADDR_ANY);
 	sin->sin_port = htons ((unsigned short) 0);
 	if (bind (sockfd, (struct sockaddr *) sin, length) < 0 ||
 		   getsockname (sockfd, (struct sockaddr *) sin, &length) < 0)
 	{
 		close (sockfd);
 		memset (secret, '\0', sizeof (secret));
 		error("rc_send_server: bind: %s: %m", server_name);
 		return (ERROR_RC);
 	}

 	retry_max = data->retries;	/* Max. numbers to try for reply */
 	retries = 0;			/* Init retry cnt for blocking call */

 	/* Build a request */
 	auth = (AUTH_HDR *) send_buffer;
 	auth->code = data->code;
 	auth->id = data->seq_nbr;

 	if (data->code == PW_ACCOUNTING_REQUEST)
 	{
 		total_length = rc_pack_list(data->send_pairs, secret, auth) + AUTH_HDR_LEN;

 		auth->length = htons ((unsigned short) total_length);

 		memset((char *) auth->vector, 0, AUTH_VECTOR_LEN);
 		secretlen = strlen (secret);
 		memcpy ((char *) auth + total_length, secret, secretlen);
 		rc_md5_calc (vector, (char *) auth, total_length + secretlen);
 		memcpy ((char *) auth->vector, (char *) vector, AUTH_VECTOR_LEN);
 	}
 	else
 	{
 		rc_random_vector (vector);
 		memcpy (auth->vector, vector, AUTH_VECTOR_LEN);

 		total_length = rc_pack_list(data->send_pairs, secret, auth) + AUTH_HDR_LEN;

 		auth->length = htons ((unsigned short) total_length);
 	}

 	sin = (struct sockaddr_in *) & saremote;
 	memset ((char *) sin, '\0', sizeof (saremote));
 	sin->sin_family = AF_INET;
 	sin->sin_addr.s_addr = htonl (auth_ipaddr);
 	sin->sin_port = htons ((unsigned short) data->svc_port);

 	for (;;)
 	{
 		sendto (sockfd, (char *) auth, (unsigned int) total_length, (int) 0,
 			(struct sockaddr *) sin, sizeof (struct sockaddr_in));

 		authtime.tv_usec = 0L;
 		authtime.tv_sec = (long) data->timeout;
 		FD_ZERO (&readfds);
 		FD_SET (sockfd, &readfds);
 		if (select (sockfd + 1, &readfds, NULL, NULL, &authtime) < 0)
 		{
 			if (errno == EINTR)
 				continue;
 			error("rc_send_server: select: %m");
 			memset (secret, '\0', sizeof (secret));
 			close (sockfd);
 			return (ERROR_RC);
 		}
 		if (FD_ISSET (sockfd, &readfds))
 			break;

 		/*
 		 * Timed out waiting for response.  Retry "retry_max" times
 		 * before giving up.  If retry_max = 0, don't retry at all.
 		 */
 		if (++retries >= retry_max)
 		{
 			error("rc_send_server: no reply from RADIUS server %s:%u",
 			      rc_ip_hostname (auth_ipaddr), data->svc_port);
 			close (sockfd);
 			memset (secret, '\0', sizeof (secret));
 			return (TIMEOUT_RC);
 		}
 	}
 	salen = sizeof (saremote);
 	length = recvfrom (sockfd, (char *) recv_buffer,
 			   (int) sizeof (recv_buffer),
 			   (int) 0, &saremote, &salen);

 	if (length <= 0)
 	{
 		error("rc_send_server: recvfrom: %s:%d: %m", server_name,\
 		      data->svc_port);
 		close (sockfd);
 		memset (secret, '\0', sizeof (secret));
 		return (ERROR_RC);
 	}

 	recv_auth = (AUTH_HDR *)recv_buffer;

 	result = rc_check_reply (recv_auth, BUFFER_LEN, secret, vector, data->seq_nbr);

 	data->receive_pairs = rc_avpair_gen(recv_auth);

 	close (sockfd);
 	if (info)
 	{
 		memcpy(info->secret, secret, sizeof(info->secret));
 		memcpy(info->request_vector, vector,
 		       sizeof(info->request_vector));
 	}
 	memset (secret, '\0', sizeof (secret));

 	if (result != OK_RC) return (result);

 	*msg = '\0';
 	vp = data->receive_pairs;
 	while (vp)
 	{
 		if ((vp = rc_avpair_get(vp, PW_REPLY_MESSAGE)))
 		{
 			strcat(msg, vp->strvalue);
 			strcat(msg, "\n");
 			vp = vp->next;
 		}
 	}

 	if ((recv_auth->code == PW_ACCESS_ACCEPT) ||
 		(recv_auth->code == PW_PASSWORD_ACK) ||
 		(recv_auth->code == PW_ACCOUNTING_RESPONSE))
 	{
 		result = OK_RC;
 	}
 	else
 	{
 		result = BADRESP_RC;
 	}

 	return (result);
 }

 /*
  * Function: rc_check_reply
  *
  * Purpose: verify items in returned packet.
  *
  * Returns:	OK_RC       -- upon success,
  *		BADRESP_RC  -- if anything looks funny.
  *
  */

 static int rc_check_reply (AUTH_HDR *auth, int bufferlen, char *secret,
 			   unsigned char *vector, unsigned char seq_nbr)
 {
 	int             secretlen;
 	int             totallen;
 	unsigned char   calc_digest[AUTH_VECTOR_LEN];
 	unsigned char   reply_digest[AUTH_VECTOR_LEN];

 	totallen = ntohs (auth->length);

 	secretlen = strlen (secret);

 	/* Do sanity checks on packet length */
 	if ((totallen < 20) || (totallen > 4096))
 	{
 		error("rc_check_reply: received RADIUS server response with invalid length");
 		return (BADRESP_RC);
 	}

 	/* Verify buffer space, should never trigger with current buffer size and check above */
 	if ((totallen + secretlen) > bufferlen)
 	{
 		error("rc_check_reply: not enough buffer space to verify RADIUS server response");
 		return (BADRESP_RC);
 	}
 	/* Verify that id (seq. number) matches what we sent */
 	if (auth->id != seq_nbr)
 	{
 		error("rc_check_reply: received non-matching id in RADIUS server response");
 		return (BADRESP_RC);
 	}

 	/* Verify the reply digest */
 	memcpy ((char *) reply_digest, (char *) auth->vector, AUTH_VECTOR_LEN);
 	memcpy ((char *) auth->vector, (char *) vector, AUTH_VECTOR_LEN);
 	memcpy ((char *) auth + totallen, secret, secretlen);
 	rc_md5_calc (calc_digest, (char *) auth, totallen + secretlen);

 #ifdef DIGEST_DEBUG
 	{
 		int i;

 		fputs("reply_digest: ", stderr);
 		for (i = 0; i < AUTH_VECTOR_LEN; i++)
 		{
 			fprintf(stderr,"%.2x ", (int) reply_digest[i]);
 		}
 		fputs("\ncalc_digest:  ", stderr);
 		for (i = 0; i < AUTH_VECTOR_LEN; i++)
 		{
 			fprintf(stderr,"%.2x ", (int) calc_digest[i]);
 		}
 		fputs("\n", stderr);
 	}
 #endif

 	if (memcmp ((char *) reply_digest, (char *) calc_digest,
 		    AUTH_VECTOR_LEN) != 0)
 	{
 #ifdef RADIUS_116
 		/* the original Livingston radiusd v1.16 seems to have
 		   a bug in digest calculation with accounting requests,
 		   authentication request are ok. i looked at the code
 		   but couldn't find any bugs. any help to get this
 		   kludge out are welcome. preferably i want to
 		   reproduce the calculation bug here to be compatible
 		   to stock Livingston radiusd v1.16.	-lf, 03/14/96
 		 */
 		if (auth->code == PW_ACCOUNTING_RESPONSE)
 			return (OK_RC);
 #endif
 		error("rc_check_reply: received invalid reply digest from RADIUS server");
 		return (BADRESP_RC);
 	}

 	return (OK_RC);

 }

 /*
  * Function: rc_random_vector
  *
  * Purpose: generates a random vector of AUTH_VECTOR_LEN octets.
  *
  * Returns: the vector (call by reference)
  *
  */

 static void rc_random_vector (unsigned char *vector)
 {
 	int             randno;
 	int             i;
 	int		fd;

 /* well, I added this to increase the security for user passwords.
    we use /dev/urandom here, as /dev/random might block and we don't
    need that much randomness. BTW, great idea, Ted!     -lf, 03/18/95	*/

 	if ((fd = open(_PATH_DEV_URANDOM, O_RDONLY)) >= 0)
 	{
 		unsigned char *pos;
 		int readcount;

 		i = AUTH_VECTOR_LEN;
 		pos = vector;
 		while (i > 0)
 		{
 			readcount = read(fd, (char *)pos, i);
 			pos += readcount;
 			i -= readcount;
 		}

 		close(fd);
 		return;
 	} /* else fall through */

 	for (i = 0; i < AUTH_VECTOR_LEN;)
 	{
 		randno = magic();
 		memcpy ((char *) vector, (char *) &randno, sizeof (int));
 		vector += sizeof (int);
 		i += sizeof (int);
 	}

 	return;
 }
	/*
	* $Id: sendserver.c,v 1.1 2004/11/14 07:26:26 paulus Exp $
	*
	* Copyright (C) 1995,1996,1997 Lars Fenneberg
	*
	* Copyright 1992 Livingston Enterprises, Inc.
	*
	* Copyright 1992,1993, 1994,1995 The Regents of the University of Michigan
	* and Merit Network, Inc. All Rights Reserved
	*
	* See the file COPYRIGHT for the respective terms and conditions.
	* If the file is missing contact me at lf@elemental.net
	* and I'll send you a copy.
	*
	*/

	#include <includes.h>
	#include <radiusclient.h>
	#include <pathnames.h>

	static void rc_random_vector (unsigned char *);
	static int rc_check_reply (AUTH_HDR , int, char , unsigned char *, unsigned char);

	/*
	* Function: rc_pack_list
	*
	* Purpose: Packs an attribute value pair list into a buffer.
	*
	* Returns: Number of octets packed.
	*
	*/

	static int rc_pack_list (VALUE_PAIR vp, char secret, AUTH_HDR *auth)
	{
	int length, i, pc, secretlen, padded_length;
	int total_length = 0;
	UINT4 lvalue;
	unsigned char passbuf[MAX(AUTH_PASS_LEN, CHAP_VALUE_LENGTH)];
	unsigned char md5buf[256];
	unsigned char buf, vector, *lenptr;

	buf = auth->data;

	while (vp != (VALUE_PAIR *) NULL)
	{

	if (vp->vendorcode != VENDOR_NONE) {
	*buf++ = PW_VENDOR_SPECIFIC;

	/* Place-holder for where to put length */
	lenptr = buf++;

	/* Insert vendor code */
	*buf++ = 0;
	*buf++ = (((unsigned int) vp->vendorcode) >> 16) & 255;
	*buf++ = (((unsigned int) vp->vendorcode) >> 8) & 255;
	*buf++ = ((unsigned int) vp->vendorcode) & 255;

	/* Insert vendor-type */
	*buf++ = vp->attribute;

	/* Insert value */
	switch(vp->type) {
	case PW_TYPE_STRING:
	length = vp->lvalue;
	*lenptr = length + 8;
	*buf++ = length+2;
	memcpy(buf, vp->strvalue, (size_t) length);
	buf += length;
	total_length += length+8;
	break;
	case PW_TYPE_INTEGER:
	case PW_TYPE_IPADDR:
	length = sizeof(UINT4);
	*lenptr = length + 8;
	*buf++ = length+2;
	lvalue = htonl(vp->lvalue);
	memcpy(buf, (char *) &lvalue, sizeof(UINT4));
	buf += length;
	total_length += length+8;
	break;
	default:
	break;
	}
	} else {
	*buf++ = vp->attribute;
	switch (vp->attribute) {
	case PW_USER_PASSWORD:

	/* Encrypt the password */

	/* Chop off password at AUTH_PASS_LEN */
	length = vp->lvalue;
	if (length > AUTH_PASS_LEN) length = AUTH_PASS_LEN;

	/* Calculate the padded length */
	padded_length = (length+(AUTH_VECTOR_LEN-1)) & ~(AUTH_VECTOR_LEN-1);

	/* Record the attribute length */
	*buf++ = padded_length + 2;

	/* Pad the password with zeros */
	memset ((char *) passbuf, '\0', AUTH_PASS_LEN);
	memcpy ((char *) passbuf, vp->strvalue, (size_t) length);

	secretlen = strlen (secret);
	vector = (char *)auth->vector;
	for(i = 0; i < padded_length; i += AUTH_VECTOR_LEN) {
	/* Calculate the MD5 digest*/
	strcpy ((char *) md5buf, secret);
	memcpy ((char *) md5buf + secretlen, vector,
	AUTH_VECTOR_LEN);
	rc_md5_calc (buf, md5buf, secretlen + AUTH_VECTOR_LEN);

	/* Remeber the start of the digest */
	vector = buf;

	/* Xor the password into the MD5 digest */
	for (pc = i; pc < (i + AUTH_VECTOR_LEN); pc++) {
	*buf++ ^= passbuf[pc];
	}
	}

	total_length += padded_length + 2;

	break;
	#if 0
	case PW_CHAP_PASSWORD:

	*buf++ = CHAP_VALUE_LENGTH + 2;

	/* Encrypt the Password */
	length = vp->lvalue;
	if (length > CHAP_VALUE_LENGTH) {
	length = CHAP_VALUE_LENGTH;
	}
	memset ((char *) passbuf, '\0', CHAP_VALUE_LENGTH);
	memcpy ((char *) passbuf, vp->strvalue, (size_t) length);

	/* Calculate the MD5 Digest */
	secretlen = strlen (secret);
	strcpy ((char *) md5buf, secret);
	memcpy ((char ) md5buf + secretlen, (char ) auth->vector,
	AUTH_VECTOR_LEN);
	rc_md5_calc (buf, md5buf, secretlen + AUTH_VECTOR_LEN);

	/* Xor the password into the MD5 digest */
	for (i = 0; i < CHAP_VALUE_LENGTH; i++) {
	*buf++ ^= passbuf[i];
	}
	total_length += CHAP_VALUE_LENGTH + 2;

	break;
	#endif
	default:
	switch (vp->type) {
	case PW_TYPE_STRING:
	length = vp->lvalue;
	*buf++ = length + 2;
	memcpy (buf, vp->strvalue, (size_t) length);
	buf += length;
	total_length += length + 2;
	break;

	case PW_TYPE_INTEGER:
	case PW_TYPE_IPADDR:
	*buf++ = sizeof (UINT4) + 2;
	lvalue = htonl (vp->lvalue);
	memcpy (buf, (char *) &lvalue, sizeof (UINT4));
	buf += sizeof (UINT4);
	total_length += sizeof (UINT4) + 2;
	break;

	default:
	break;
	}
	break;
	}
	}
	vp = vp->next;
	}
	return total_length;
	}

	/*
	* Function: rc_send_server
	*
	* Purpose: send a request to a RADIUS server and wait for the reply
	*
	*/

	int rc_send_server (SEND_DATA data, char msg, REQUEST_INFO *info)
	{
	int sockfd;
	struct sockaddr salocal;
	struct sockaddr saremote;
	struct sockaddr_in *sin;
	struct timeval authtime;
	fd_set readfds;
	AUTH_HDR auth, recv_auth;
	UINT4 auth_ipaddr;
	char server_name; / Name of server to query */
	int salen;
	int result;
	int total_length;
	int length;
	int retry_max;
	int secretlen;
	char secret[MAX_SECRET_LENGTH + 1];
	unsigned char vector[AUTH_VECTOR_LEN];
	char recv_buffer[BUFFER_LEN];
	char send_buffer[BUFFER_LEN];
	int retries;
	VALUE_PAIR *vp;

	server_name = data->server;
	if (server_name == (char *) NULL \|\| server_name[0] == '\0')
	return (ERROR_RC);

	if ((vp = rc_avpair_get(data->send_pairs, PW_SERVICE_TYPE)) && \
	(vp->lvalue == PW_ADMINISTRATIVE))
	{
	strcpy(secret, MGMT_POLL_SECRET);
	if ((auth_ipaddr = rc_get_ipaddr(server_name)) == 0)
	return (ERROR_RC);
	}
	else
	{
	if (rc_find_server (server_name, &auth_ipaddr, secret) != 0)
	{
	return (ERROR_RC);
	}
	}

	sockfd = socket (AF_INET, SOCK_DGRAM, 0);
	if (sockfd < 0)
	{
	memset (secret, '\0', sizeof (secret));
	error("rc_send_server: socket: %s", strerror(errno));
	return (ERROR_RC);
	}

	length = sizeof (salocal);
	sin = (struct sockaddr_in *) & salocal;
	memset ((char *) sin, '\0', (size_t) length);
	sin->sin_family = AF_INET;
	sin->sin_addr.s_addr = htonl(INADDR_ANY);
	sin->sin_port = htons ((unsigned short) 0);
	if (bind (sockfd, (struct sockaddr *) sin, length) < 0 \|\|
	getsockname (sockfd, (struct sockaddr *) sin, &length) < 0)
	{
	close (sockfd);
	memset (secret, '\0', sizeof (secret));
	error("rc_send_server: bind: %s: %m", server_name);
	return (ERROR_RC);
	}

	retry_max = data->retries; /* Max. numbers to try for reply */
	retries = 0; /* Init retry cnt for blocking call */

	/* Build a request */
	auth = (AUTH_HDR *) send_buffer;
	auth->code = data->code;
	auth->id = data->seq_nbr;

	if (data->code == PW_ACCOUNTING_REQUEST)
	{
	total_length = rc_pack_list(data->send_pairs, secret, auth) + AUTH_HDR_LEN;

	auth->length = htons ((unsigned short) total_length);

	memset((char *) auth->vector, 0, AUTH_VECTOR_LEN);
	secretlen = strlen (secret);
	memcpy ((char *) auth + total_length, secret, secretlen);
	rc_md5_calc (vector, (char *) auth, total_length + secretlen);
	memcpy ((char ) auth->vector, (char ) vector, AUTH_VECTOR_LEN);
	}
	else
	{
	rc_random_vector (vector);
	memcpy (auth->vector, vector, AUTH_VECTOR_LEN);

	total_length = rc_pack_list(data->send_pairs, secret, auth) + AUTH_HDR_LEN;

	auth->length = htons ((unsigned short) total_length);
	}

	sin = (struct sockaddr_in *) & saremote;
	memset ((char *) sin, '\0', sizeof (saremote));
	sin->sin_family = AF_INET;
	sin->sin_addr.s_addr = htonl (auth_ipaddr);
	sin->sin_port = htons ((unsigned short) data->svc_port);

	for (;;)
	{
	sendto (sockfd, (char *) auth, (unsigned int) total_length, (int) 0,
	(struct sockaddr *) sin, sizeof (struct sockaddr_in));

	authtime.tv_usec = 0L;
	authtime.tv_sec = (long) data->timeout;
	FD_ZERO (&readfds);
	FD_SET (sockfd, &readfds);
	if (select (sockfd + 1, &readfds, NULL, NULL, &authtime) < 0)
	{
	if (errno == EINTR)
	continue;
	error("rc_send_server: select: %m");
	memset (secret, '\0', sizeof (secret));
	close (sockfd);
	return (ERROR_RC);
	}
	if (FD_ISSET (sockfd, &readfds))
	break;

	/*
	* Timed out waiting for response. Retry "retry_max" times
	* before giving up. If retry_max = 0, don't retry at all.
	*/
	if (++retries >= retry_max)
	{
	error("rc_send_server: no reply from RADIUS server %s:%u",
	rc_ip_hostname (auth_ipaddr), data->svc_port);
	close (sockfd);
	memset (secret, '\0', sizeof (secret));
	return (TIMEOUT_RC);
	}
	}
	salen = sizeof (saremote);
	length = recvfrom (sockfd, (char *) recv_buffer,
	(int) sizeof (recv_buffer),
	(int) 0, &saremote, &salen);

	if (length <= 0)
	{
	error("rc_send_server: recvfrom: %s:%d: %m", server_name,\
	data->svc_port);
	close (sockfd);
	memset (secret, '\0', sizeof (secret));
	return (ERROR_RC);
	}

	recv_auth = (AUTH_HDR *)recv_buffer;

	result = rc_check_reply (recv_auth, BUFFER_LEN, secret, vector, data->seq_nbr);

	data->receive_pairs = rc_avpair_gen(recv_auth);

	close (sockfd);
	if (info)
	{
	memcpy(info->secret, secret, sizeof(info->secret));
	memcpy(info->request_vector, vector,
	sizeof(info->request_vector));
	}
	memset (secret, '\0', sizeof (secret));

	if (result != OK_RC) return (result);

	*msg = '\0';
	vp = data->receive_pairs;
	while (vp)
	{
	if ((vp = rc_avpair_get(vp, PW_REPLY_MESSAGE)))
	{
	strcat(msg, vp->strvalue);
	strcat(msg, "\n");
	vp = vp->next;
	}
	}

	if ((recv_auth->code == PW_ACCESS_ACCEPT) \|\|
	(recv_auth->code == PW_PASSWORD_ACK) \|\|
	(recv_auth->code == PW_ACCOUNTING_RESPONSE))
	{
	result = OK_RC;
	}
	else
	{
	result = BADRESP_RC;
	}

	return (result);
	}

	/*
	* Function: rc_check_reply
	*
	* Purpose: verify items in returned packet.
	*
	* Returns: OK_RC -- upon success,
	* BADRESP_RC -- if anything looks funny.
	*
	*/

	static int rc_check_reply (AUTH_HDR auth, int bufferlen, char secret,
	unsigned char *vector, unsigned char seq_nbr)
	{
	int secretlen;
	int totallen;
	unsigned char calc_digest[AUTH_VECTOR_LEN];
	unsigned char reply_digest[AUTH_VECTOR_LEN];

	totallen = ntohs (auth->length);

	secretlen = strlen (secret);

	/* Do sanity checks on packet length */
	if ((totallen < 20) \|\| (totallen > 4096))
	{
	error("rc_check_reply: received RADIUS server response with invalid length");
	return (BADRESP_RC);
	}

	/* Verify buffer space, should never trigger with current buffer size and check above */
	if ((totallen + secretlen) > bufferlen)
	{
	error("rc_check_reply: not enough buffer space to verify RADIUS server response");
	return (BADRESP_RC);
	}
	/* Verify that id (seq. number) matches what we sent */
	if (auth->id != seq_nbr)
	{
	error("rc_check_reply: received non-matching id in RADIUS server response");
	return (BADRESP_RC);
	}

	/* Verify the reply digest */
	memcpy ((char ) reply_digest, (char ) auth->vector, AUTH_VECTOR_LEN);
	memcpy ((char ) auth->vector, (char ) vector, AUTH_VECTOR_LEN);
	memcpy ((char *) auth + totallen, secret, secretlen);
	rc_md5_calc (calc_digest, (char *) auth, totallen + secretlen);

	#ifdef DIGEST_DEBUG
	{
	int i;

	fputs("reply_digest: ", stderr);
	for (i = 0; i < AUTH_VECTOR_LEN; i++)
	{
	fprintf(stderr,"%.2x ", (int) reply_digest[i]);
	}
	fputs("\ncalc_digest: ", stderr);
	for (i = 0; i < AUTH_VECTOR_LEN; i++)
	{
	fprintf(stderr,"%.2x ", (int) calc_digest[i]);
	}
	fputs("\n", stderr);
	}
	#endif

	if (memcmp ((char ) reply_digest, (char ) calc_digest,
	AUTH_VECTOR_LEN) != 0)
	{
	#ifdef RADIUS_116
	/* the original Livingston radiusd v1.16 seems to have
	a bug in digest calculation with accounting requests,
	authentication request are ok. i looked at the code
	but couldn't find any bugs. any help to get this
	kludge out are welcome. preferably i want to
	reproduce the calculation bug here to be compatible
	to stock Livingston radiusd v1.16. -lf, 03/14/96
	*/
	if (auth->code == PW_ACCOUNTING_RESPONSE)
	return (OK_RC);
	#endif
	error("rc_check_reply: received invalid reply digest from RADIUS server");
	return (BADRESP_RC);
	}

	return (OK_RC);

	}

	/*
	* Function: rc_random_vector
	*
	* Purpose: generates a random vector of AUTH_VECTOR_LEN octets.
	*
	* Returns: the vector (call by reference)
	*
	*/

	static void rc_random_vector (unsigned char *vector)
	{
	int randno;
	int i;
	int fd;

	/* well, I added this to increase the security for user passwords.
	we use /dev/urandom here, as /dev/random might block and we don't
	need that much randomness. BTW, great idea, Ted! -lf, 03/18/95 */

	if ((fd = open(_PATH_DEV_URANDOM, O_RDONLY)) >= 0)
	{
	unsigned char *pos;
	int readcount;

	i = AUTH_VECTOR_LEN;
	pos = vector;
	while (i > 0)
	{
	readcount = read(fd, (char *)pos, i);
	pos += readcount;
	i -= readcount;
	}

	close(fd);
	return;
	} /* else fall through */

	for (i = 0; i < AUTH_VECTOR_LEN;)
	{
	randno = magic();
	memcpy ((char ) vector, (char ) &randno, sizeof (int));
	vector += sizeof (int);
	i += sizeof (int);
	}

	return;
	}