radius.c

/*
 *   This library is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU Lesser General Public
 *   License as published by the Free Software Foundation; either
 *   version 2.1 of the License, or (at your option) any later version.
 *
 *   This library is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 *   Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public
 *   License along with this library; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

/**
 * $Id$
 *
 * @file radius.c
 * @brief Functions to send/receive radius packets.
 *
 * @copyright 2000-2003,2006  The FreeRADIUS server project
 */

RCSID("$Id$")

#include	<freeradius-devel/libradius.h>

#include	<freeradius-devel/md5.h>

#include	<fcntl.h>
#include	<ctype.h>

#ifdef WITH_UDPFROMTO
#include	<freeradius-devel/udpfromto.h>
#endif

/*
 *	Some messages get printed out only in debugging mode.
 */
#define FR_DEBUG_STRERROR_PRINTF if (fr_debug_lvl) fr_strerror_printf

#if 0
#define VP_TRACE printf

static void VP_HEXDUMP(char const *msg, uint8_t const *data, size_t len)
{
	size_t i;

	printf("--- %s ---\n", msg);
	for (i = 0; i < len; i++) {
		if ((i & 0x0f) == 0) printf("%04x: ", (unsigned int) i);
		printf("%02x ", data[i]);
		if ((i & 0x0f) == 0x0f) printf("\n");
	}
	if ((len == 0x0f) || ((len & 0x0f) != 0x0f)) printf("\n");
	fflush(stdout);
}

#else
#define VP_TRACE(_x, ...)
#define VP_HEXDUMP(_x, _y, _z)
#endif


/*
 *  The RFC says 4096 octets max, and most packets are less than 256.
 */
#define MAX_PACKET_LEN 4096

/*
 *	The maximum number of attributes which we allow in an incoming
 *	request.  If there are more attributes than this, the request
 *	is rejected.
 *
 *	This helps to minimize the potential for a DoS, when an
 *	attacker spoofs Access-Request packets, which don't have a
 *	Message-Authenticator attribute.  This means that the packet
 *	is unsigned, and the attacker can use resources on the server,
 *	even if the end request is rejected.
 */
uint32_t fr_max_attributes = 0;
FILE *fr_log_fp = NULL;

typedef struct radius_packet_t {
  uint8_t	code;
  uint8_t	id;
  uint8_t	length[2];
  uint8_t	vector[AUTH_VECTOR_LEN];
  uint8_t	data[1];
} radius_packet_t;

static fr_randctx fr_rand_pool;	/* across multiple calls */
static int fr_rand_initialized = 0;
static unsigned int salt_offset = 0;
static uint8_t nullvector[AUTH_VECTOR_LEN] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; /* for CoA decode */

char const *fr_packet_codes[FR_MAX_PACKET_CODE] = {
  "",					//!< 0
  "Access-Request",
  "Access-Accept",
  "Access-Reject",
  "Accounting-Request",
  "Accounting-Response",
  "Accounting-Status",
  "Password-Request",
  "Password-Accept",
  "Password-Reject",
  "Accounting-Message",			//!< 10
  "Access-Challenge",
  "Status-Server",
  "Status-Client",
  "14",
  "15",
  "16",
  "17",
  "18",
  "19",
  "20",					//!< 20
  "Resource-Free-Request",
  "Resource-Free-Response",
  "Resource-Query-Request",
  "Resource-Query-Response",
  "Alternate-Resource-Reclaim-Request",
  "NAS-Reboot-Request",
  "NAS-Reboot-Response",
  "28",
  "Next-Passcode",
  "New-Pin",				//!< 30
  "Terminate-Session",
  "Password-Expired",
  "Event-Request",
  "Event-Response",
  "35",
  "36",
  "37",
  "38",
  "39",
  "Disconnect-Request",			//!< 40
  "Disconnect-ACK",
  "Disconnect-NAK",
  "CoA-Request",
  "CoA-ACK",
  "CoA-NAK",
  "46",
  "47",
  "48",
  "49",
  "IP-Address-Allocate",
  "IP-Address-Release",			//!< 50
};


void fr_printf_log(char const *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	if ((fr_debug_lvl == 0) || !fr_log_fp) {
		va_end(ap);
		return;
	}

	vfprintf(fr_log_fp, fmt, ap);
	va_end(ap);

	return;
}

static char const tabs[] = "\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t";

static void print_hex_data(uint8_t const *ptr, int attrlen, int depth)
{
	int i;

	for (i = 0; i < attrlen; i++) {
		if ((i > 0) && ((i & 0x0f) == 0x00))
			fprintf(fr_log_fp, "%.*s", depth, tabs);
		fprintf(fr_log_fp, "%02x ", ptr[i]);
		if ((i & 0x0f) == 0x0f) fprintf(fr_log_fp, "\n");
	}
	if ((i & 0x0f) != 0) fprintf(fr_log_fp, "\n");
}


void rad_print_hex(RADIUS_PACKET *packet)
{
	int i;

	if (!packet->data || !fr_log_fp) return;

	fprintf(fr_log_fp, "  Code:\t\t%u\n", packet->data[0]);
	fprintf(fr_log_fp, "  Id:\t\t%u\n", packet->data[1]);
	fprintf(fr_log_fp, "  Length:\t%u\n", ((packet->data[2] << 8) |
				   (packet->data[3])));
	fprintf(fr_log_fp, "  Vector:\t");
	for (i = 4; i < 20; i++) {
		fprintf(fr_log_fp, "%02x", packet->data[i]);
	}
	fprintf(fr_log_fp, "\n");

	if (packet->data_len > 20) {
		int total;
		uint8_t const *ptr;
		fprintf(fr_log_fp, "  Data:");

		total = packet->data_len - 20;
		ptr = packet->data + 20;

		while (total > 0) {
			int attrlen;
			unsigned int vendor = 0;

			fprintf(fr_log_fp, "\t\t");
			if (total < 2) { /* too short */
				fprintf(fr_log_fp, "%02x\n", *ptr);
				break;
			}

			if (ptr[1] > total) { /* too long */
				for (i = 0; i < total; i++) {
					fprintf(fr_log_fp, "%02x ", ptr[i]);
				}
				break;
			}

			fprintf(fr_log_fp, "%02x  %02x  ", ptr[0], ptr[1]);
			attrlen = ptr[1] - 2;

			if ((ptr[0] == PW_VENDOR_SPECIFIC) &&
			    (attrlen > 4)) {
				vendor = (ptr[3] << 16) | (ptr[4] << 8) | ptr[5];
				fprintf(fr_log_fp, "%02x%02x%02x%02x (%u)  ",
				       ptr[2], ptr[3], ptr[4], ptr[5], vendor);
				attrlen -= 4;
				ptr += 6;
				total -= 6;

			} else {
				ptr += 2;
				total -= 2;
			}

			print_hex_data(ptr, attrlen, 3);

			ptr += attrlen;
			total -= attrlen;
		}
	}
	fflush(stdout);
}

/** Wrapper for sendto which handles sendfromto, IPv6, and all possible combinations
 *
 */
static int rad_sendto(int sockfd, void *data, size_t data_len, int flags,
#ifdef WITH_UDPFROMTO
		      fr_ipaddr_t *src_ipaddr, uint16_t src_port,
#else
		      UNUSED fr_ipaddr_t *src_ipaddr, UNUSED uint16_t src_port,
#endif
		      fr_ipaddr_t *dst_ipaddr, uint16_t dst_port)
{
	int rcode;
	struct sockaddr_storage	dst;
	socklen_t		sizeof_dst;

#ifdef WITH_UDPFROMTO
	struct sockaddr_storage	src;
	socklen_t		sizeof_src;

	fr_ipaddr2sockaddr(src_ipaddr, src_port, &src, &sizeof_src);
#endif

	if (!fr_ipaddr2sockaddr(dst_ipaddr, dst_port, &dst, &sizeof_dst)) {
		return -1;
	}

#ifdef WITH_UDPFROMTO
	/*
	 *	And if they don't specify a source IP address, don't
	 *	use udpfromto.
	 */
	if (((dst_ipaddr->af == AF_INET) || (dst_ipaddr->af == AF_INET6)) &&
	    (src_ipaddr->af != AF_UNSPEC) &&
	    !fr_inaddr_any(src_ipaddr)) {
		rcode = sendfromto(sockfd, data, data_len, flags,
				   (struct sockaddr *)&src, sizeof_src,
				   (struct sockaddr *)&dst, sizeof_dst);
		goto done;
	}
#endif

	/*
	 *	No udpfromto, fail gracefully.
	 */
	rcode = sendto(sockfd, data, data_len, flags,
		       (struct sockaddr *) &dst, sizeof_dst);
#ifdef WITH_UDPFROMTO
done:
#endif
	if (rcode < 0) {
		fr_strerror_printf("sendto failed: %s", fr_syserror(errno));
	}

	return rcode;
}


void rad_recv_discard(int sockfd)
{
	uint8_t			header[4];
	struct sockaddr_storage	src;
	socklen_t		sizeof_src = sizeof(src);

	(void) recvfrom(sockfd, header, sizeof(header), 0,
			(struct sockaddr *)&src, &sizeof_src);
}

/** Basic validation of RADIUS packet header
 *
 * @note fr_strerror errors are only available if fr_debug_lvl > 0. This is to reduce CPU time
 *	consumed when discarding malformed packet.
 *
 * @param[in] sockfd we're reading from.
 * @param[out] src_ipaddr of the packet.
 * @param[out] src_port of the packet.
 * @param[out] code Pointer to where to write the packet code.
 * @return
 *	- -1 on failure.
 *	- 1 on decode error.
 *	- >= RADIUS_HDR_LEN on success. This is the packet length as specified in the header.
 */
ssize_t rad_recv_header(int sockfd, fr_ipaddr_t *src_ipaddr, uint16_t *src_port, int *code)
{
	ssize_t			data_len, packet_len;
	uint8_t			header[4];
	struct sockaddr_storage	src;
	socklen_t		sizeof_src = sizeof(src);

	data_len = recvfrom(sockfd, header, sizeof(header), MSG_PEEK,
			    (struct sockaddr *)&src, &sizeof_src);
	if (data_len < 0) {
		if ((errno == EAGAIN) || (errno == EINTR)) return 0;
		return -1;
	}

	/*
	 *	Too little data is available, discard the packet.
	 */
	if (data_len < 4) {
		FR_DEBUG_STRERROR_PRINTF("Expected at least 4 bytes of header data, got %zu bytes", data_len);
		rad_recv_discard(sockfd);

		return 1;

	} else {		/* we got 4 bytes of data. */
		/*
		 *	See how long the packet says it is.
		 */
		packet_len = (header[2] * 256) + header[3];

		/*
		 *	The length in the packet says it's less than
		 *	a RADIUS header length: discard it.
		 */
		if (packet_len < RADIUS_HDR_LEN) {
			FR_DEBUG_STRERROR_PRINTF("Expected at least " STRINGIFY(RADIUS_HDR_LEN)  " bytes of packet "
					   	 "data, got %zu bytes", packet_len);
			rad_recv_discard(sockfd);

			return 1;

			/*
			 *	Enforce RFC requirements, for sanity.
			 *	Anything after 4k will be discarded.
			 */
		} else if (packet_len > MAX_PACKET_LEN) {
			FR_DEBUG_STRERROR_PRINTF("Length field value too large, expected maximum of "
					   	 STRINGIFY(MAX_PACKET_LEN) " bytes, got %zu bytes", packet_len);
			rad_recv_discard(sockfd);

			return 1;
		}
	}

	/*
	 *	Convert AF.  If unknown, discard packet.
	 */
	if (!fr_sockaddr2ipaddr(&src, sizeof_src, src_ipaddr, src_port)) {
		FR_DEBUG_STRERROR_PRINTF("Unkown address family");
		rad_recv_discard(sockfd);

		return 1;
	}

	*code = header[0];

	/*
	 *	The packet says it's this long, but the actual UDP
	 *	size could still be smaller.
	 */
	return packet_len;
}


/** Wrapper for recvfrom, which handles recvfromto, IPv6, and all possible combinations
 *
 */
static ssize_t rad_recvfrom(int sockfd, RADIUS_PACKET *packet, int flags,
			    fr_ipaddr_t *src_ipaddr, uint16_t *src_port,
			    fr_ipaddr_t *dst_ipaddr, uint16_t *dst_port)
{
	struct sockaddr_storage	src;
	struct sockaddr_storage	dst;
	socklen_t		sizeof_src = sizeof(src);
	socklen_t		sizeof_dst = sizeof(dst);
	ssize_t			data_len;
	uint8_t			header[4];
	size_t			len;
	uint16_t		port;

	memset(&src, 0, sizeof_src);
	memset(&dst, 0, sizeof_dst);

	/*
	 *	Read the length of the packet, from the packet.
	 *	This lets us allocate the buffer to use for
	 *	reading the rest of the packet.
	 */
	data_len = recvfrom(sockfd, header, sizeof(header), MSG_PEEK,
			    (struct sockaddr *)&src, &sizeof_src);
	if (data_len < 0) {
		if ((errno == EAGAIN) || (errno == EINTR)) return 0;
		return -1;
	}

	/*
	 *	Too little data is available, discard the packet.
	 */
	if (data_len < 4) {
		rad_recv_discard(sockfd);

		return 0;

	} else {		/* we got 4 bytes of data. */
		/*
		 *	See how long the packet says it is.
		 */
		len = (header[2] * 256) + header[3];

		/*
		 *	The length in the packet says it's less than
		 *	a RADIUS header length: discard it.
		 */
		if (len < RADIUS_HDR_LEN) {
			recvfrom(sockfd, header, sizeof(header), flags,
				 (struct sockaddr *)&src, &sizeof_src);
			return 0;

			/*
			 *	Enforce RFC requirements, for sanity.
			 *	Anything after 4k will be discarded.
			 */
		} else if (len > MAX_PACKET_LEN) {
			recvfrom(sockfd, header, sizeof(header), flags,
				 (struct sockaddr *)&src, &sizeof_src);
			return len;
		}
	}

	packet->data = talloc_array(packet, uint8_t, len);
	if (!packet->data) return -1;

	/*
	 *	Receive the packet.  The OS will discard any data in the
	 *	packet after "len" bytes.
	 */
#ifdef WITH_UDPFROMTO
	data_len = recvfromto(sockfd, packet->data, len, flags,
			      (struct sockaddr *)&src, &sizeof_src,
			      (struct sockaddr *)&dst, &sizeof_dst);
#else
	data_len = recvfrom(sockfd, packet->data, len, flags,
			    (struct sockaddr *)&src, &sizeof_src);

	/*
	 *	Get the destination address, too.
	 */
	if (getsockname(sockfd, (struct sockaddr *)&dst,
			&sizeof_dst) < 0) return -1;
#endif
	if (data_len < 0) {
		return data_len;
	}

	if (!fr_sockaddr2ipaddr(&src, sizeof_src, src_ipaddr, &port)) {
		return -1;	/* Unknown address family, Die Die Die! */
	}
	*src_port = port;

	fr_sockaddr2ipaddr(&dst, sizeof_dst, dst_ipaddr, &port);
	*dst_port = port;

	/*
	 *	Different address families should never happen.
	 */
	if (src.ss_family != dst.ss_family) {
		return -1;
	}

	return data_len;
}


#define AUTH_PASS_LEN (AUTH_VECTOR_LEN)
/** Build an encrypted secret value to return in a reply packet
 *
 * The secret is hidden by xoring with a MD5 digest created from
 * the shared secret and the authentication vector.
 * We put them into MD5 in the reverse order from that used when
 * encrypting passwords to RADIUS.
 */
static void make_secret(uint8_t *digest, uint8_t const *vector,
			char const *secret, uint8_t const *value)
{
	FR_MD5_CTX context;
	int	     i;

	fr_md5_init(&context);
	fr_md5_update(&context, vector, AUTH_VECTOR_LEN);
	fr_md5_update(&context, (uint8_t const *) secret, strlen(secret));
	fr_md5_final(digest, &context);

	for ( i = 0; i < AUTH_VECTOR_LEN; i++ ) {
		digest[i] ^= value[i];
	}
}

#define MAX_PASS_LEN (128)
static void make_passwd(uint8_t *output, ssize_t *outlen,
			uint8_t const *input, size_t inlen,
			char const *secret, uint8_t const *vector)
{
	FR_MD5_CTX context, old;
	uint8_t	digest[AUTH_VECTOR_LEN];
	uint8_t passwd[MAX_PASS_LEN];
	size_t	i, n;
	size_t	len;

	/*
	 *	If the length is zero, round it up.
	 */
	len = inlen;

	if (len > MAX_PASS_LEN) len = MAX_PASS_LEN;

	memcpy(passwd, input, len);
	if (len < sizeof(passwd)) memset(passwd + len, 0, sizeof(passwd) - len);

	if (len == 0) {
		len = AUTH_PASS_LEN;
	}

	else if ((len & 0x0f) != 0) {
		len += 0x0f;
		len &= ~0x0f;
	}
	*outlen = len;

	fr_md5_init(&context);
	fr_md5_update(&context, (uint8_t const *) secret, strlen(secret));
	old = context;

	/*
	 *	Do first pass.
	 */
	fr_md5_update(&context, vector, AUTH_PASS_LEN);

	for (n = 0; n < len; n += AUTH_PASS_LEN) {
		if (n > 0) {
			context = old;
			fr_md5_update(&context,
				       passwd + n - AUTH_PASS_LEN,
				       AUTH_PASS_LEN);
		}

		fr_md5_final(digest, &context);
		for (i = 0; i < AUTH_PASS_LEN; i++) {
			passwd[i + n] ^= digest[i];
		}
	}

	memcpy(output, passwd, len);
}

static void make_tunnel_passwd(uint8_t *output, ssize_t *outlen,
			       uint8_t const *input, size_t inlen, size_t room,
			       char const *secret, uint8_t const *vector)
{
	FR_MD5_CTX context, old;
	uint8_t	digest[AUTH_VECTOR_LEN];
	uint8_t passwd[MAX_STRING_LEN + AUTH_VECTOR_LEN];
	int	i, n;
	int	len;

	/*
	 *	Be paranoid.
	 */
	if (room > 253) room = 253;

	/*
	 *	Account for 2 bytes of the salt, and round the room
	 *	available down to the nearest multiple of 16.  Then,
	 *	subtract one from that to account for the length byte,
	 *	and the resulting number is the upper bound on the data
	 *	to copy.
	 *
	 *	We could short-cut this calculation just be forcing
	 *	inlen to be no more than 239.  It would work for all
	 *	VSA's, as we don't pack multiple VSA's into one
	 *	attribute.
	 *
	 *	However, this calculation is more general, if a little
	 *	complex.  And it will work in the future for all possible
	 *	kinds of weird attribute packing.
	 */
	room -= 2;
	room -= (room & 0x0f);
	room--;

	if (inlen > room) inlen = room;

	/*
	 *	Length of the encrypted data is password length plus
	 *	one byte for the length of the password.
	 */
	len = inlen + 1;
	if ((len & 0x0f) != 0) {
		len += 0x0f;
		len &= ~0x0f;
	}
	*outlen = len + 2;	/* account for the salt */

	/*
	 *	Copy the password over.
	 */
	memcpy(passwd + 3, input, inlen);
	memset(passwd + 3 + inlen, 0, sizeof(passwd) - 3 - inlen);

	/*
	 *	Generate salt.  The RFC's say:
	 *
	 *	The high bit of salt[0] must be set, each salt in a
	 *	packet should be unique, and they should be random
	 *
	 *	So, we set the high bit, add in a counter, and then
	 *	add in some CSPRNG data.  should be OK..
	 */
	passwd[0] = (0x80 | ( ((salt_offset++) & 0x0f) << 3) |
		     (fr_rand() & 0x07));
	passwd[1] = fr_rand();
	passwd[2] = inlen;	/* length of the password string */

	fr_md5_init(&context);
	fr_md5_update(&context, (uint8_t const *) secret, strlen(secret));
	old = context;

	fr_md5_update(&context, vector, AUTH_VECTOR_LEN);
	fr_md5_update(&context, &passwd[0], 2);

	for (n = 0; n < len; n += AUTH_PASS_LEN) {
		if (n > 0) {
			context = old;
			fr_md5_update(&context,
				       passwd + 2 + n - AUTH_PASS_LEN,
				       AUTH_PASS_LEN);
		}

		fr_md5_final(digest, &context);

		for (i = 0; i < AUTH_PASS_LEN; i++) {
			passwd[i + 2 + n] ^= digest[i];
		}
	}
	memcpy(output, passwd, len + 2);
}

static int do_next_tlv(VALUE_PAIR const *vp, VALUE_PAIR const *next, int nest)
{
	unsigned int tlv1, tlv2;

	if (nest > fr_attr_max_tlv) return 0;

	if (!vp) return 0;

	/*
	 *	Keep encoding TLVs which have the same scope.
	 *	e.g. two attributes of:
	 *		ATTR.TLV1.TLV2.TLV3 = data1
	 *		ATTR.TLV1.TLV2.TLV4 = data2
	 *	both get put into a container of "ATTR.TLV1.TLV2"
	 */

	/*
	 *	Nothing to follow, we're done.
	 */
	if (!next) return 0;

	/*
	 *	Not from the same vendor, skip it.
	 */
	if (vp->da->vendor != next->da->vendor) return 0;

	/*
	 *	In a different TLV space, skip it.
	 */
	tlv1 = vp->da->attr;
	tlv2 = next->da->attr;

	tlv1 &= ((1 << fr_attr_shift[nest]) - 1);
	tlv2 &= ((1 << fr_attr_shift[nest]) - 1);

	if (tlv1 != tlv2) return 0;

	return 1;
}


static ssize_t vp2data_any(RADIUS_PACKET const *packet,
			   RADIUS_PACKET const *original,
			   char const *secret, int nest,
			   VALUE_PAIR const **pvp,
			   uint8_t *start, size_t room);

static ssize_t vp2attr_rfc(RADIUS_PACKET const *packet,
			   RADIUS_PACKET const *original,
			   char const *secret, VALUE_PAIR const **pvp,
			   unsigned int attribute, uint8_t *ptr, size_t room);

/** Encode the *data* portion of the TLV
 *
 * This is really a sub-function of vp2data_any().  It encodes the *data* portion
 * of the TLV, and assumes that the encapsulating attribute has already been encoded.
 */
static ssize_t vp2data_tlvs(RADIUS_PACKET const *packet,
			    RADIUS_PACKET const *original,
			    char const *secret, int nest,
			    VALUE_PAIR const **pvp,
			    uint8_t *start, size_t room)
{
	ssize_t len;
	size_t my_room;
	uint8_t *ptr = start;
	VALUE_PAIR const *vp = *pvp;
	VALUE_PAIR const *svp = vp;

	if (!svp) return 0;

#ifndef NDEBUG
	if (nest > fr_attr_max_tlv) {
		fr_strerror_printf("vp2data_tlvs: attribute nesting overflow");
		return -1;
	}
#endif

	while (vp) {
		VERIFY_VP(vp);

		if (room <= 2) return ptr - start;

		ptr[0] = (vp->da->attr >> fr_attr_shift[nest]) & fr_attr_mask[nest];
		ptr[1] = 2;

		my_room = room;
		if (room > 255) my_room = 255;

		len = vp2data_any(packet, original, secret, nest,
				  &vp, ptr + 2, my_room - 2);
		if (len < 0) return len;
		if (len == 0) return ptr - start;
		/* len can NEVER be more than 253 */

		ptr[1] += len;

#ifndef NDEBUG
		if ((fr_debug_lvl > 3) && fr_log_fp) {
			fprintf(fr_log_fp, "\t\t%02x %02x  ", ptr[0], ptr[1]);
			print_hex_data(ptr + 2, len, 3);
		}
#endif

		room -= ptr[1];
		ptr += ptr[1];
		*pvp = vp;

		if (!do_next_tlv(svp, vp, nest)) break;
	}

#ifndef NDEBUG
	if ((fr_debug_lvl > 3) && fr_log_fp) {
		DICT_ATTR const *da;

		da = dict_attrbyvalue(svp->da->attr & ((1 << fr_attr_shift[nest ]) - 1), svp->da->vendor);
		if (da) fprintf(fr_log_fp, "\t%s = ...\n", da->name);
	}
#endif

	return ptr - start;
}

/** Encodes the data portion of an attribute
 *
 * @return
 *	- Length of the data portion.
 *	- -1 on failure.
 */
static ssize_t vp2data_any(RADIUS_PACKET const *packet,
			   RADIUS_PACKET const *original,
			   char const *secret, int nest,
			   VALUE_PAIR const **pvp,
			   uint8_t *start, size_t room)
{
	uint32_t lvalue;
	ssize_t len;
	uint8_t const *data;
	uint8_t *ptr = start;
	uint8_t	array[4];
	uint64_t lvalue64;
	VALUE_PAIR const *vp = *pvp;

	VERIFY_VP(vp);

	/*
	 *	See if we need to encode a TLV.  The low portion of
	 *	the attribute has already been placed into the packer.
	 *	If there are still attribute bytes left, then go
	 *	encode them as TLVs.
	 *
	 *	If we cared about the stack, we could unroll the loop.
	 */
	if (vp->da->flags.is_tlv && (nest < fr_attr_max_tlv) &&
	    ((vp->da->attr >> fr_attr_shift[nest + 1]) != 0)) {
		return vp2data_tlvs(packet, original, secret, nest + 1, pvp,
				    start, room);
	}

	/*
	 *	Set up the default sources for the data.
	 */
	len = vp->vp_length;

	switch (vp->da->type) {
	case PW_TYPE_STRING:
	case PW_TYPE_OCTETS:
	case PW_TYPE_TLV:
		data = vp->data.ptr;
		if (!data) {
			fr_strerror_printf("ERROR: Cannot encode NULL data");
			return -1;
		}
		break;

	case PW_TYPE_IFID:
	case PW_TYPE_IPV4_ADDR:
	case PW_TYPE_IPV6_ADDR:
	case PW_TYPE_IPV6_PREFIX:
	case PW_TYPE_IPV4_PREFIX:
	case PW_TYPE_ABINARY:
	case PW_TYPE_ETHERNET:	/* just in case */
		data = (uint8_t const *) &vp->data;
		break;

	case PW_TYPE_BYTE:
		len = 1;	/* just in case */
		array[0] = vp->vp_byte;
		data = array;
		break;

	case PW_TYPE_SHORT:
		len = 2;	/* just in case */
		array[0] = (vp->vp_short >> 8) & 0xff;
		array[1] = vp->vp_short & 0xff;
		data = array;
		break;

	case PW_TYPE_INTEGER:
		len = 4;	/* just in case */
		lvalue = htonl(vp->vp_integer);
		memcpy(array, &lvalue, sizeof(lvalue));
		data = array;
		break;

	case PW_TYPE_INTEGER64:
		len = 8;	/* just in case */
		lvalue64 = htonll(vp->vp_integer64);
		data = (uint8_t *) &lvalue64;
		break;

		/*
		 *  There are no tagged date attributes.
		 */
	case PW_TYPE_DATE:
		lvalue = htonl(vp->vp_date);
		data = (uint8_t const *) &lvalue;
		len = 4;	/* just in case */
		break;

	case PW_TYPE_SIGNED:
	{
		int32_t slvalue;

		len = 4;	/* just in case */
		slvalue = htonl(vp->vp_signed);
		memcpy(array, &slvalue, sizeof(slvalue));
		data = array;
		break;
	}

	default:		/* unknown type: ignore it */
		fr_strerror_printf("ERROR: Unknown attribute type %d", vp->da->type);
		return -1;
	}

	/*
	 *	No data: skip it.
	 */
	if (len == 0) {
		*pvp = vp->next;
		return 0;
	}

	/*
	 *	Bound the data to the calling size
	 */
	if (len > (ssize_t) room) len = room;

	/*
	 *	Encrypt the various password styles
	 *
	 *	Attributes with encrypted values MUST be less than
	 *	128 bytes long.
	 */
	switch (vp->da->flags.encrypt) {
	case FLAG_ENCRYPT_USER_PASSWORD:
		make_passwd(ptr, &len, data, len,
			    secret, packet->vector);
		break;

	case FLAG_ENCRYPT_TUNNEL_PASSWORD:
		lvalue = 0;
		if (vp->da->flags.has_tag) lvalue = 1;

		/*
		 *	Check if there's enough room.  If there isn't,
		 *	we discard the attribute.
		 *
		 *	This is ONLY a problem if we have multiple VSA's
		 *	in one Vendor-Specific, though.
		 */
		if (room < (18 + lvalue)) return 0;

		switch (packet->code) {
		case PW_CODE_ACCESS_ACCEPT:
		case PW_CODE_ACCESS_REJECT:
		case PW_CODE_ACCESS_CHALLENGE:
		default:
			if (!original) {
				fr_strerror_printf("ERROR: No request packet, cannot encrypt %s attribute in the vp.", vp->da->name);
				return -1;
			}

			if (lvalue) ptr[0] = TAG_VALID(vp->tag) ? vp->tag : TAG_NONE;
			make_tunnel_passwd(ptr + lvalue, &len, data, len,
					   room - lvalue,
					   secret, original->vector);
			break;
		case PW_CODE_ACCOUNTING_REQUEST:
		case PW_CODE_DISCONNECT_REQUEST:
		case PW_CODE_COA_REQUEST:
			ptr[0] = TAG_VALID(vp->tag) ? vp->tag : TAG_NONE;
			make_tunnel_passwd(ptr + 1, &len, data, len - 1, room,
					   secret, packet->vector);
			break;
		}
		break;

		/*
		 *	The code above ensures that this attribute
		 *	always fits.
		 */
	case FLAG_ENCRYPT_ASCEND_SECRET:
		if (len != 16) return 0;
		make_secret(ptr, packet->vector, secret, data);
		len = AUTH_VECTOR_LEN;
		break;


	default:
		if (vp->da->flags.has_tag && TAG_VALID(vp->tag)) {
			if (vp->da->type == PW_TYPE_STRING) {
				if (len > ((ssize_t) (room - 1))) len = room - 1;
				ptr[0] = vp->tag;
				ptr++;
			} else if (vp->da->type == PW_TYPE_INTEGER) {
				array[0] = vp->tag;
			} /* else it can't be any other type */
		}
		memcpy(ptr, data, len);
		break;
	} /* switch over encryption flags */

	*pvp = vp->next;
	return len + (ptr - start);
}

static ssize_t attr_shift(uint8_t const *start, uint8_t const *end,
			  uint8_t *ptr, int hdr_len, ssize_t len,
			  int flag_offset, int vsa_offset)
{
	int check_len = len - ptr[1];
	int total = len + hdr_len;

	/*
	 *	Pass 1: Check if the addition of the headers
	 *	overflows the available room.  If so, return
	 *	what we were capable of encoding.
	 */

	while (check_len > (255 - hdr_len)) {
		total += hdr_len;
		check_len -= (255 - hdr_len);
	}

	/*
	 *	Note that this results in a number of attributes maybe
	 *	being marked as "encoded", but which aren't in the
	 *	packet.  Oh well.  The solution is to fix the
	 *	"vp2data_any" function to take into account the header
	 *	lengths.
	 */
	if ((ptr + ptr[1] + total) > end) {
		return (ptr + ptr[1]) - start;
	}

	/*
	 *	Pass 2: Now that we know there's enough room,
	 *	re-arrange the data to form a set of valid
	 *	RADIUS attributes.
	 */
	while (1) {
		int sublen = 255 - ptr[1];

		if (len <= sublen) {
			break;
		}

		len -= sublen;
		memmove(ptr + 255 + hdr_len, ptr + 255, sublen);
		memcpy(ptr + 255, ptr, hdr_len);
		ptr[1] += sublen;
		if (vsa_offset) ptr[vsa_offset] += sublen;
		ptr[flag_offset] |= 0x80;

		ptr += 255;
		ptr[1] = hdr_len;
		if (vsa_offset) ptr[vsa_offset] = 3;
	}

	ptr[1] += len;
	if (vsa_offset) ptr[vsa_offset] += len;

	return (ptr + ptr[1]) - start;
}


/** Encode an "extended" attribute
 */
int rad_vp2extended(RADIUS_PACKET const *packet,
		    RADIUS_PACKET const *original,
		    char const *secret, VALUE_PAIR const **pvp,
		    uint8_t *ptr, size_t room)
{
	int len;
	int hdr_len;
	uint8_t *start = ptr;
	VALUE_PAIR const *vp = *pvp;

	VERIFY_VP(vp);

	if (!vp->da->flags.extended) {
		fr_strerror_printf("rad_vp2extended called for non-extended attribute");
		return -1;
	}

	/*
	 *	The attribute number is encoded into the upper 8 bits
	 *	of the vendor ID.
	 */
	ptr[0] = (vp->da->vendor / FR_MAX_VENDOR) & 0xff;

	if (!vp->da->flags.long_extended) {
		if (room < 3) return 0;

		ptr[1] = 3;
		ptr[2] = vp->da->attr & fr_attr_mask[0];

	} else {
		if (room < 4) return 0;

		ptr[1] = 4;
		ptr[2] = vp->da->attr & fr_attr_mask[0];
		ptr[3] = 0;
	}

	/*
	 *	Only "flagged" attributes can be longer than one
	 *	attribute.
	 */
	if (!vp->da->flags.long_extended && (room > 255)) {
		room = 255;
	}

	/*
	 *	Handle EVS VSAs.
	 */
	if (vp->da->flags.evs) {
		uint8_t *evs = ptr + ptr[1];

		if (room < (size_t) (ptr[1] + 5)) return 0;

		ptr[2] = 26;

		evs[0] = 0;	/* always zero */
		evs[1] = (vp->da->vendor >> 16) & 0xff;
		evs[2] = (vp->da->vendor >> 8) & 0xff;
		evs[3] = vp->da->vendor & 0xff;
		evs[4] = vp->da->attr & fr_attr_mask[0];

		ptr[1] += 5;
	}
	hdr_len = ptr[1];

	len = vp2data_any(packet, original, secret, 0,
			  pvp, ptr + ptr[1], room - hdr_len);
	if (len <= 0) return len;

	/*
	 *	There may be more than 252 octets of data encoded in
	 *	the attribute.  If so, move the data up in the packet,
	 *	and copy the existing header over.  Set the "M" flag ONLY
	 *	after copying the rest of the data.
	 */
	if (vp->da->flags.long_extended && (len > (255 - ptr[1]))) {
		return attr_shift(start, start + room, ptr, 4, len, 3, 0);
	}

	ptr[1] += len;

#ifndef NDEBUG
	if ((fr_debug_lvl > 3) && fr_log_fp) {
		int jump = 3;

		fprintf(fr_log_fp, "\t\t%02x %02x  ", ptr[0], ptr[1]);
		if (!vp->da->flags.long_extended) {
			fprintf(fr_log_fp, "%02x  ", ptr[2]);

		} else {
			fprintf(fr_log_fp, "%02x %02x  ", ptr[2], ptr[3]);
			jump = 4;
		}

		if (vp->da->flags.evs) {
			fprintf(fr_log_fp, "%02x%02x%02x%02x (%u)  %02x  ",
				ptr[jump], ptr[jump + 1],
				ptr[jump + 2], ptr[jump + 3],
				((ptr[jump + 1] << 16) |
				 (ptr[jump + 2] << 8) |
				 ptr[jump + 3]),
				ptr[jump + 4]);
			jump += 5;
		}

		print_hex_data(ptr + jump, len, 3);
	}
#endif

	return (ptr + ptr[1]) - start;
}


/** Encode a WiMAX attribute
 *
 */
int rad_vp2wimax(RADIUS_PACKET const *packet,
		 RADIUS_PACKET const *original,
		 char const *secret, VALUE_PAIR const **pvp,
		 uint8_t *ptr, size_t room)
{
	int len;
	uint32_t lvalue;
	int hdr_len;
	uint8_t *start = ptr;
	VALUE_PAIR const *vp = *pvp;

	VERIFY_VP(vp);

	/*
	 *	Double-check for WiMAX format.
	 */
	if (!vp->da->flags.wimax) {
		fr_strerror_printf("rad_vp2wimax called for non-WIMAX VSA");
		return -1;
	}

	/*
	 *	Not enough room for:
	 *		attr, len, vendor-id, vsa, vsalen, continuation
	 */
	if (room < 9) return 0;

	/*
	 *	Build the Vendor-Specific header
	 */
	ptr = start;
	ptr[0] = PW_VENDOR_SPECIFIC;
	ptr[1] = 9;
	lvalue = htonl(vp->da->vendor);
	memcpy(ptr + 2, &lvalue, 4);
	ptr[6] = (vp->da->attr & fr_attr_mask[1]);
	ptr[7] = 3;
	ptr[8] = 0;		/* continuation byte */

	hdr_len = 9;

	len = vp2data_any(packet, original, secret, 0, pvp, ptr + ptr[1],
			  room - hdr_len);
	if (len <= 0) return len;

	/*
	 *	There may be more than 252 octets of data encoded in
	 *	the attribute.  If so, move the data up in the packet,
	 *	and copy the existing header over.  Set the "C" flag
	 *	ONLY after copying the rest of the data.
	 */
	if (len > (255 - ptr[1])) {
		return attr_shift(start, start + room, ptr, hdr_len, len, 8, 7);
	}

	ptr[1] += len;
	ptr[7] += len;

#ifndef NDEBUG
	if ((fr_debug_lvl > 3) && fr_log_fp) {
		fprintf(fr_log_fp, "\t\t%02x %02x  %02x%02x%02x%02x (%u)  %02x %02x %02x   ",
		       ptr[0], ptr[1],
		       ptr[2], ptr[3], ptr[4], ptr[5],
		       (ptr[3] << 16) | (ptr[4] << 8) | ptr[5],
		       ptr[6], ptr[7], ptr[8]);
		print_hex_data(ptr + 9, len, 3);
	}
#endif

	return (ptr + ptr[1]) - start;
}

/** Encode an RFC format attribute, with the "concat" flag set
 *
 * If there isn't enough room in the packet, the data is
 * truncated to fit.
 */
static ssize_t vp2attr_concat(UNUSED RADIUS_PACKET const *packet,
			      UNUSED RADIUS_PACKET const *original,
			      UNUSED char const *secret, VALUE_PAIR const **pvp,
			      unsigned int attribute, uint8_t *start, size_t room)
{
	uint8_t *ptr = start;
	uint8_t const *p;
	size_t len, left;
	VALUE_PAIR const *vp = *pvp;

	VERIFY_VP(vp);

	p = vp->vp_octets;
	len = vp->vp_length;

	while (len > 0) {
		if (room <= 2) break;

		ptr[0] = attribute;
		ptr[1] = 2;

		left = len;

		/* no more than 253 octets */
		if (left > 253) left = 253;

		/* no more than "room" octets */
		if (room < (left + 2)) left = room - 2;

		memcpy(ptr + 2, p, left);

#ifndef NDEBUG
		if ((fr_debug_lvl > 3) && fr_log_fp) {
			fprintf(fr_log_fp, "\t\t%02x %02x  ", ptr[0], ptr[1]);
			print_hex_data(ptr + 2, len, 3);
		}
#endif
		ptr[1] += left;
		ptr += ptr[1];
		p += left;
		room -= left;
		len -= left;
	}

	*pvp = vp->next;
	return ptr - start;
}

/** Encode an RFC format TLV.
 *
 * This could be a standard attribute, or a TLV data type.
 * If it's a standard attribute, then vp->da->attr == attribute.
 * Otherwise, attribute may be something else.
 */
static ssize_t vp2attr_rfc(RADIUS_PACKET const *packet,
			   RADIUS_PACKET const *original,
			   char const *secret, VALUE_PAIR const **pvp,
			   unsigned int attribute, uint8_t *ptr, size_t room)
{
	ssize_t len;

	if (room <= 2) return 0;

	ptr[0] = attribute & 0xff;
	ptr[1] = 2;

	if (room > ((unsigned) 255 - ptr[1])) room = 255 - ptr[1];

	len = vp2data_any(packet, original, secret, 0, pvp, ptr + ptr[1], room);
	if (len <= 0) return len;

	ptr[1] += len;

#ifndef NDEBUG
	if ((fr_debug_lvl > 3) && fr_log_fp) {
		fprintf(fr_log_fp, "\t\t%02x %02x  ", ptr[0], ptr[1]);
		print_hex_data(ptr + 2, len, 3);
	}
#endif

	return ptr[1];
}


/** Encode a VSA which is a TLV
 *
 * If it's in the RFC format, call vp2attr_rfc.  Otherwise, encode it here.
 */
static ssize_t vp2attr_vsa(RADIUS_PACKET const *packet,
			   RADIUS_PACKET const *original,
			   char const *secret, VALUE_PAIR const **pvp,
			   unsigned int attribute, unsigned int vendor,
			   uint8_t *ptr, size_t room)
{
	ssize_t len;
	DICT_VENDOR *dv;
	VALUE_PAIR const *vp = *pvp;

	VERIFY_VP(vp);
	/*
	 *	Unknown vendor: RFC format.
	 *	Known vendor and RFC format: go do that.
	 */
	dv = dict_vendorbyvalue(vendor);
	if (!dv ||
	    (!vp->da->flags.is_tlv && (dv->type == 1) && (dv->length == 1))) {
		return vp2attr_rfc(packet, original, secret, pvp,
				   attribute, ptr, room);
	}

	switch (dv->type) {
	default:
		fr_strerror_printf("vp2attr_vsa: Internal sanity check failed,"
				   " type %u", (unsigned) dv->type);
		return -1;

	case 4:
		ptr[0] = 0;	/* attr must be 24-bit */
		ptr[1] = (attribute >> 16) & 0xff;
		ptr[2] = (attribute >> 8) & 0xff;
		ptr[3] = attribute & 0xff;
		break;

	case 2:
		ptr[0] = (attribute >> 8) & 0xff;
		ptr[1] = attribute & 0xff;
		break;

	case 1:
		ptr[0] = attribute & 0xff;
		break;
	}

	switch (dv->length) {
	default:
		fr_strerror_printf("vp2attr_vsa: Internal sanity check failed,"
				   " length %u", (unsigned) dv->length);
		return -1;

	case 0:
		break;

	case 2:
		ptr[dv->type] = 0;
		ptr[dv->type + 1] = dv->type + 2;
		break;

	case 1:
		ptr[dv->type] = dv->type + 1;
		break;

	}

	if (room > ((unsigned) 255 - (dv->type + dv->length))) {
		room = 255 - (dv->type + dv->length);
	}

	len = vp2data_any(packet, original, secret, 0, pvp,
			  ptr + dv->type + dv->length, room);
	if (len <= 0) return len;

	if (dv->length) ptr[dv->type + dv->length - 1] += len;

#ifndef NDEBUG
	if ((fr_debug_lvl > 3) && fr_log_fp) {
		switch (dv->type) {
		default:
			break;

		case 4:
			if ((fr_debug_lvl > 3) && fr_log_fp)
				fprintf(fr_log_fp, "\t\t%02x%02x%02x%02x ",
					ptr[0], ptr[1], ptr[2], ptr[3]);
			break;

		case 2:
			if ((fr_debug_lvl > 3) && fr_log_fp)
				fprintf(fr_log_fp, "\t\t%02x%02x ",
					ptr[0], ptr[1]);
		break;

		case 1:
			if ((fr_debug_lvl > 3) && fr_log_fp)
				fprintf(fr_log_fp, "\t\t%02x ", ptr[0]);
			break;
		}

		switch (dv->length) {
		default:
			break;

		case 0:
			fprintf(fr_log_fp, "  ");
			break;

		case 1:
			fprintf(fr_log_fp, "%02x  ",
				ptr[dv->type]);
			break;

		case 2:
			fprintf(fr_log_fp, "%02x%02x  ",
				ptr[dv->type], ptr[dv->type] + 1);
			break;
		}

		print_hex_data(ptr + dv->type + dv->length, len, 3);
	}
#endif

	return dv->type + dv->length + len;
}


/** Encode a Vendor-Specific attribute
 *
 */
int rad_vp2vsa(RADIUS_PACKET const *packet, RADIUS_PACKET const *original,
		char const *secret, VALUE_PAIR const **pvp, uint8_t *ptr,
		size_t room)
{
	ssize_t len;
	uint32_t lvalue;
	VALUE_PAIR const *vp = *pvp;

	VERIFY_VP(vp);

	if (vp->da->vendor == 0) {
		fr_strerror_printf("rad_vp2vsa called with rfc attribute");
		return -1;
	}

	/*
	 *	Double-check for WiMAX format.
	 */
	if (vp->da->flags.wimax) {
		return rad_vp2wimax(packet, original, secret, pvp, ptr, room);
	}

	if (vp->da->vendor > FR_MAX_VENDOR) {
		fr_strerror_printf("rad_vp2vsa: Invalid arguments");
		return -1;
	}

	/*
	 *	Not enough room for:
	 *		attr, len, vendor-id
	 */
	if (room < 6) return 0;

	/*
	 *	Build the Vendor-Specific header
	 */
	ptr[0] = PW_VENDOR_SPECIFIC;
	ptr[1] = 6;
	lvalue = htonl(vp->da->vendor);
	memcpy(ptr + 2, &lvalue, 4);

	if (room > ((unsigned) 255 - ptr[1])) room = 255 - ptr[1];

	len = vp2attr_vsa(packet, original, secret, pvp,
			  vp->da->attr, vp->da->vendor,
			  ptr + ptr[1], room);
	if (len < 0) return len;

#ifndef NDEBUG
	if ((fr_debug_lvl > 3) && fr_log_fp) {
		fprintf(fr_log_fp, "\t\t%02x %02x  %02x%02x%02x%02x (%u)  ",
		       ptr[0], ptr[1],
		       ptr[2], ptr[3], ptr[4], ptr[5],
		       (ptr[3] << 16) | (ptr[4] << 8) | ptr[5]);
		print_hex_data(ptr + 6, len, 3);
	}
#endif

	ptr[1] += len;

	return ptr[1];
}


/** Encode an RFC standard attribute 1..255
 *
 */
int rad_vp2rfc(RADIUS_PACKET const *packet,
	       RADIUS_PACKET const *original,
	       char const *secret, VALUE_PAIR const **pvp,
	       uint8_t *ptr, size_t room)
{
	VALUE_PAIR const *vp = *pvp;

	VERIFY_VP(vp);

	if (vp->da->vendor != 0) {
		fr_strerror_printf("rad_vp2rfc called with VSA");
		return -1;
	}

	if ((vp->da->attr == 0) || (vp->da->attr > 255)) {
		fr_strerror_printf("rad_vp2rfc called with non-standard attribute %u", vp->da->attr);
		return -1;
	}

	/*
	 *	Only CUI is allowed to have zero length.
	 *	Thank you, WiMAX!
	 */
	if ((vp->vp_length == 0) &&
	    (vp->da->attr == PW_CHARGEABLE_USER_IDENTITY)) {
		ptr[0] = PW_CHARGEABLE_USER_IDENTITY;
		ptr[1] = 2;

		*pvp = vp->next;
		return 2;
	}

	/*
	 *	Message-Authenticator is hard-coded.
	 */
	if (!vp->da->vendor && (vp->da->attr == PW_MESSAGE_AUTHENTICATOR)) {
		if (room < 18) return -1;

		ptr[0] = PW_MESSAGE_AUTHENTICATOR;
		ptr[1] = 18;
		memset(ptr + 2, 0, 16);
#ifndef NDEBUG
		if ((fr_debug_lvl > 3) && fr_log_fp) {
			fprintf(fr_log_fp, "\t\t50 12 ...\n");
		}
#endif

		*pvp = (*pvp)->next;
		return 18;
	}

	/*
	 *	EAP-Message is special.
	 */
	if (vp->da->flags.concat && (vp->vp_length > 253)) {
		return vp2attr_concat(packet, original, secret, pvp, vp->da->attr,
				      ptr, room);
	}

	return vp2attr_rfc(packet, original, secret, pvp, vp->da->attr,
			   ptr, room);
}

static ssize_t rad_vp2rfctlv(RADIUS_PACKET const *packet,
			     RADIUS_PACKET const *original,
			     char const *secret, VALUE_PAIR const **pvp,
			     uint8_t *start, size_t room)
{
	ssize_t len;
	VALUE_PAIR const *vp = *pvp;

	VERIFY_VP(vp);

	if (!vp->da->flags.is_tlv) {
		fr_strerror_printf("rad_vp2rfctlv: attr is not a TLV");
		return -1;
	}

	if ((vp->da->vendor & (FR_MAX_VENDOR - 1)) != 0) {
		fr_strerror_printf("rad_vp2rfctlv: attr is not an RFC TLV");
		return -1;
	}

	if (room < 5) return 0;

	/*
	 *	Encode the first level of TLVs
	 */
	start[0] = (vp->da->vendor / FR_MAX_VENDOR) & 0xff;
	start[1] = 4;
	start[2] = vp->da->attr & fr_attr_mask[0];
	start[3] = 2;

	len = vp2data_any(packet, original, secret, 0, pvp,
			  start + 4, room - 4);
	if (len <= 0) return len;

	if (len > 253) {
		return -1;
	}

	start[1] += len;
	start[3] += len;

	return start[1];
}

/** Parse a data structure into a RADIUS attribute
 *
 */
int rad_vp2attr(RADIUS_PACKET const *packet, RADIUS_PACKET const *original,
		char const *secret, VALUE_PAIR const **pvp, uint8_t *start,
		size_t room)
{
	VALUE_PAIR const *vp;

	if (!pvp || !*pvp || !start || (room <= 2)) return -1;

	vp = *pvp;

	VERIFY_VP(vp);

	/*
	 *	RFC format attributes take the fast path.
	 */
	if (!vp->da->vendor) {
		if (vp->da->attr > 255) return 0;

		return rad_vp2rfc(packet, original, secret, pvp,
				  start, room);
	}

	if (vp->da->flags.extended) {
		return rad_vp2extended(packet, original, secret, pvp,
				       start, room);
	}

	/*
	 *	The upper 8 bits of the vendor number are the standard
	 *	space attribute which is a TLV.
	 */
	if ((vp->da->vendor & (FR_MAX_VENDOR - 1)) == 0) {
		return rad_vp2rfctlv(packet, original, secret, pvp,
				     start, room);
	}

	if (vp->da->flags.wimax) {
		return rad_vp2wimax(packet, original, secret, pvp,
				    start, room);
	}

	return rad_vp2vsa(packet, original, secret, pvp, start, room);
}


/** Encode a packet
 *
 */
int rad_encode(RADIUS_PACKET *packet, RADIUS_PACKET const *original,
	       char const *secret)
{
	radius_packet_t		*hdr;
	uint8_t			*ptr;
	uint16_t		total_length;
	int			len;
	VALUE_PAIR const	*reply;

	/*
	 *	A 4K packet, aligned on 64-bits.
	 */
	uint64_t	data[MAX_PACKET_LEN / sizeof(uint64_t)];

	/*
	 *	Double-check some things based on packet code.
	 */
	switch (packet->code) {
	case PW_CODE_ACCESS_ACCEPT:
	case PW_CODE_ACCESS_REJECT:
	case PW_CODE_ACCESS_CHALLENGE:
		if (!original) {
			fr_strerror_printf("ERROR: Cannot sign response packet without a request packet");
			return -1;
		}
		break;

		/*
		 *	These packet vectors start off as all zero.
		 */
	case PW_CODE_ACCOUNTING_REQUEST:
	case PW_CODE_DISCONNECT_REQUEST:
	case PW_CODE_COA_REQUEST:
		memset(packet->vector, 0, sizeof(packet->vector));
		break;

	default:
		break;
	}

	/*
	 *	Use memory on the stack, until we know how
	 *	large the packet will be.
	 */
	hdr = (radius_packet_t *) data;

	/*
	 *	Build standard header
	 */
	hdr->code = packet->code;
	hdr->id = packet->id;

	memcpy(hdr->vector, packet->vector, sizeof(hdr->vector));

	total_length = RADIUS_HDR_LEN;

	/*
	 *	Load up the configuration values for the user
	 */
	ptr = hdr->data;
	packet->offset = 0;

	/*
	 *	FIXME: Loop twice over the reply list.  The first time,
	 *	calculate the total length of data.  The second time,
	 *	allocate the memory, and fill in the VP's.
	 *
	 *	Hmm... this may be slower than just doing a small
	 *	memcpy.
	 */

	/*
	 *	Loop over the reply attributes for the packet.
	 */
	reply = packet->vps;
	while (reply) {
		size_t last_len;
		char const *last_name = NULL;

		VERIFY_VP(reply);

		/*
		 *	Ignore non-wire attributes, but allow extended
		 *	attributes.
		 *
		 *	@fixme We should be able to get rid of this check
		 *	and just look at da->flags.internal
		 */
		if (reply->da->flags.internal ||
		    ((reply->da->vendor == 0) &&
		    ((reply->da->attr & 0xFFFF) >= 256) &&
		    !reply->da->flags.extended && !reply->da->flags.long_extended)) {
#ifndef NDEBUG
			/*
			 *	Permit the admin to send BADLY formatted
			 *	attributes with a debug build.
			 */
			if (reply->da->attr == PW_RAW_ATTRIBUTE) {
				memcpy(ptr, reply->vp_octets, reply->vp_length);
				len = reply->vp_length;
				reply = reply->next;
				goto next;
			}
#endif
			reply = reply->next;
			continue;
		}

		/*
		 *	Set the Message-Authenticator to the correct
		 *	length and initial value.
		 */
		if (!reply->da->vendor && (reply->da->attr == PW_MESSAGE_AUTHENTICATOR)) {
			/*
			 *	Cache the offset to the
			 *	Message-Authenticator
			 */
			packet->offset = total_length;
			last_len = 16;
		} else {
			last_len = reply->vp_length;
		}
		last_name = reply->da->name;

		len = rad_vp2attr(packet, original, secret, &reply, ptr,
				  ((uint8_t *) data) + sizeof(data) - ptr);
		if (len < 0) return -1;

		/*
		 *	Failed to encode the attribute, likely because
		 *	the packet is full.
		 */
		if (len == 0) {
			if (last_len != 0) {
				fr_strerror_printf("WARNING: Failed encoding attribute %s\n", last_name);
				break;
			} else {
				fr_strerror_printf("WARNING: Skipping zero-length attribute %s\n", last_name);
			}
		}

#ifndef NDEBUG
	next:			/* Used only for Raw-Attribute */
#endif
		ptr += len;
		total_length += len;
	} /* done looping over all attributes */

	/*
	 *	Fill in the rest of the fields, and copy the data over
	 *	from the local stack to the newly allocated memory.
	 *
	 *	Yes, all this 'memcpy' is slow, but it means
	 *	that we only allocate the minimum amount of
	 *	memory for a request.
	 */
	packet->data_len = total_length;
	packet->data = talloc_array(packet, uint8_t, packet->data_len);
	if (!packet->data) {
		fr_strerror_printf("Out of memory");
		return -1;
	}

	memcpy(packet->data, hdr, packet->data_len);
	hdr = (radius_packet_t *) packet->data;

	total_length = htons(total_length);
	memcpy(hdr->length, &total_length, sizeof(total_length));

	return 0;
}


/** Sign a previously encoded packet
 *
 */
int rad_sign(RADIUS_PACKET *packet, RADIUS_PACKET const *original,
	     char const *secret)
{
	radius_packet_t	*hdr = (radius_packet_t *)packet->data;

	/*
	 *	It wasn't assigned an Id, this is bad!
	 */
	if (packet->id < 0) {
		fr_strerror_printf("ERROR: RADIUS packets must be assigned an Id");
		return -1;
	}

	if (!packet->data || (packet->data_len < RADIUS_HDR_LEN) ||
	    (packet->offset < 0)) {
		fr_strerror_printf("ERROR: You must call rad_encode() before rad_sign()");
		return -1;
	}

	/*
	 *	If there's a Message-Authenticator, update it
	 *	now, BEFORE updating the authentication vector.
	 */
	if (packet->offset > 0) {
		uint8_t calc_auth_vector[AUTH_VECTOR_LEN];

		switch (packet->code) {
		case PW_CODE_ACCOUNTING_RESPONSE:
			if (original && original->code == PW_CODE_STATUS_SERVER) {
				goto do_ack;
			}

		case PW_CODE_ACCOUNTING_REQUEST:
		case PW_CODE_DISCONNECT_REQUEST:
		case PW_CODE_DISCONNECT_ACK:
		case PW_CODE_DISCONNECT_NAK:
		case PW_CODE_COA_REQUEST:
		case PW_CODE_COA_ACK:
			memset(hdr->vector, 0, AUTH_VECTOR_LEN);
			break;

		do_ack:
		case PW_CODE_ACCESS_ACCEPT:
		case PW_CODE_ACCESS_REJECT:
		case PW_CODE_ACCESS_CHALLENGE:
			if (!original) {
				fr_strerror_printf("ERROR: Cannot sign response packet without a request packet");
				return -1;
			}
			memcpy(hdr->vector, original->vector,
			       AUTH_VECTOR_LEN);
			break;

		default:	/* others have vector already set to zero */
			break;

		}

		/*
		 *	Set the authentication vector to zero,
		 *	calculate the HMAC, and put it
		 *	into the Message-Authenticator
		 *	attribute.
		 */
		fr_hmac_md5(calc_auth_vector, packet->data, packet->data_len,
			    (uint8_t const *) secret, strlen(secret));
		memcpy(packet->data + packet->offset + 2,
		       calc_auth_vector, AUTH_VECTOR_LEN);

		/*
		 *	Copy the original request vector back
		 *	to the raw packet.
		 */
		memcpy(hdr->vector, packet->vector, AUTH_VECTOR_LEN);
	}

	/*
	 *	Switch over the packet code, deciding how to
	 *	sign the packet.
	 */
	switch (packet->code) {
		/*
		 *	Request packets are not signed, bur
		 *	have a random authentication vector.
		 */
	case PW_CODE_ACCESS_REQUEST:
	case PW_CODE_STATUS_SERVER:
		break;

		/*
		 *	Reply packets are signed with the
		 *	authentication vector of the request.
		 */
	default:
		{
			uint8_t digest[16];

			FR_MD5_CTX	context;
			fr_md5_init(&context);
			fr_md5_update(&context, packet->data, packet->data_len);
			fr_md5_update(&context, (uint8_t const *) secret,
				     strlen(secret));
			fr_md5_final(digest, &context);

			memcpy(hdr->vector, digest, AUTH_VECTOR_LEN);
			memcpy(packet->vector, digest, AUTH_VECTOR_LEN);
			break;
		}
	}/* switch over packet codes */

	return 0;
}

/** Reply to the request
 *
 * Also attach reply attribute value pairs and any user message provided.
 */
int rad_send(RADIUS_PACKET *packet, RADIUS_PACKET const *original,
	     char const *secret)
{
	/*
	 *	Maybe it's a fake packet.  Don't send it.
	 */
	if (!packet || (packet->sockfd < 0)) {
		return 0;
	}

	/*
	 *  First time through, allocate room for the packet
	 */
	if (!packet->data) {
		/*
		 *	Encode the packet.
		 */
		if (rad_encode(packet, original, secret) < 0) {
			return -1;
		}

		/*
		 *	Re-sign it, including updating the
		 *	Message-Authenticator.
		 */
		if (rad_sign(packet, original, secret) < 0) {
			return -1;
		}

		/*
		 *	If packet->data points to data, then we print out
		 *	the VP list again only for debugging.
		 */
	}

#ifndef NDEBUG
	if ((fr_debug_lvl > 3) && fr_log_fp) rad_print_hex(packet);
#endif

#ifdef WITH_TCP
	/*
	 *	If the socket is TCP, call write().  Calling sendto()
	 *	is allowed on some platforms, but it's not nice.  Even
	 *	worse, if UDPFROMTO is defined, we *can't* use it on
	 *	TCP sockets.  So... just call write().
	 */
	if (packet->proto == IPPROTO_TCP) {
		ssize_t rcode;

		rcode = write(packet->sockfd, packet->data, packet->data_len);
		if (rcode >= 0) return rcode;

		fr_strerror_printf("sendto failed: %s", fr_syserror(errno));
		return -1;
	}
#endif

	/*
	 *	And send it on it's way.
	 */
	return rad_sendto(packet->sockfd, packet->data, packet->data_len, 0,
			  &packet->src_ipaddr, packet->src_port,
			  &packet->dst_ipaddr, packet->dst_port);
}

/** Do a comparison of two authentication digests by comparing the FULL digest
 *
 * Otherwise, the server can be subject to timing attacks that allow attackers
 * find a valid message authenticator.
 *
 * http://www.cs.rice.edu/~dwallach/pub/crosby-timing2009.pdf
 */
int rad_digest_cmp(uint8_t const *a, uint8_t const *b, size_t length)
{
	int result = 0;
	size_t i;

	for (i = 0; i < length; i++) {
		result |= a[i] ^ b[i];
	}

	return result;		/* 0 is OK, !0 is !OK, just like memcmp */
}


/** Validates the requesting client NAS
 *
 * Calculates the request Authenticator based on the clients private key.
 */
static int calc_acctdigest(RADIUS_PACKET *packet, char const *secret)
{
	uint8_t		digest[AUTH_VECTOR_LEN];
	FR_MD5_CTX		context;

	/*
	 *	Zero out the auth_vector in the received packet.
	 *	Then append the shared secret to the received packet,
	 *	and calculate the MD5 sum. This must be the same
	 *	as the original MD5 sum (packet->vector).
	 */
	memset(packet->data + 4, 0, AUTH_VECTOR_LEN);

	/*
	 *  MD5(packet + secret);
	 */
	fr_md5_init(&context);
	fr_md5_update(&context, packet->data, packet->data_len);
	fr_md5_update(&context, (uint8_t const *) secret, strlen(secret));
	fr_md5_final(digest, &context);

	/*
	 *	Return 0 if OK, 2 if not OK.
	 */
	if (rad_digest_cmp(digest, packet->vector, AUTH_VECTOR_LEN) != 0) return 2;
	return 0;
}


/** Validates the requesting client NAS
 *
 * Calculates the response Authenticator based on the clients
 * private key.
 */
static int calc_replydigest(RADIUS_PACKET *packet, RADIUS_PACKET *original,
			    char const *secret)
{
	uint8_t		calc_digest[AUTH_VECTOR_LEN];
	FR_MD5_CTX		context;

	/*
	 *	Very bad!
	 */
	if (original == NULL) {
		return 3;
	}

	/*
	 *  Copy the original vector in place.
	 */
	memcpy(packet->data + 4, original->vector, AUTH_VECTOR_LEN);

	/*
	 *  MD5(packet + secret);
	 */
	fr_md5_init(&context);
	fr_md5_update(&context, packet->data, packet->data_len);
	fr_md5_update(&context, (uint8_t const *) secret, strlen(secret));
	fr_md5_final(calc_digest, &context);

	/*
	 *  Copy the packet's vector back to the packet.
	 */
	memcpy(packet->data + 4, packet->vector, AUTH_VECTOR_LEN);

	/*
	 *	Return 0 if OK, 2 if not OK.
	 */
	if (rad_digest_cmp(packet->vector, calc_digest, AUTH_VECTOR_LEN) != 0) return 2;
	return 0;
}

/** Check if a set of RADIUS formatted TLVs are OK
 *
 */
int rad_tlv_ok(uint8_t const *data, size_t length,
	       size_t dv_type, size_t dv_length)
{
	uint8_t const *end = data + length;

	VP_TRACE("checking TLV %u/%u\n", (unsigned int) dv_type, (unsigned int) dv_length);

	VP_HEXDUMP("tlv_ok", data, length);

	if ((dv_length > 2) || (dv_type == 0) || (dv_type > 4)) {
		fr_strerror_printf("rad_tlv_ok: Invalid arguments");
		return -1;
	}

	while (data < end) {
		size_t attrlen;

		if ((data + dv_type + dv_length) > end) {
			fr_strerror_printf("Attribute header overflow");
			return -1;
		}

		switch (dv_type) {
		case 4:
			if ((data[0] == 0) && (data[1] == 0) &&
			    (data[2] == 0) && (data[3] == 0)) {
			zero:
				fr_strerror_printf("Invalid attribute 0");
				return -1;
			}

			if (data[0] != 0) {
				fr_strerror_printf("Invalid attribute > 2^24");
				return -1;
			}
			break;

		case 2:
			if ((data[0] == 0) && (data[1] == 0)) goto zero;
			break;

		case 1:
			/*
			 *	Zero is allowed, because the Colubris
			 *	people are dumb and use it.
			 */
			break;

		default:
			fr_strerror_printf("Internal sanity check failed");
			return -1;
		}

		switch (dv_length) {
		case 0:
			return 0;

		case 2:
			if (data[dv_type] != 0) {
				fr_strerror_printf("Attribute is longer than 256 octets");
				return -1;
			}
			/* FALL-THROUGH */
		case 1:
			attrlen = data[dv_type + dv_length - 1];
			break;


		default:
			fr_strerror_printf("Internal sanity check failed");
			return -1;
		}

		if (attrlen < (dv_type + dv_length)) {
			fr_strerror_printf("Attribute header has invalid length");
			return -1;
		}

		if (attrlen > length) {
			fr_strerror_printf("Attribute overflows container");
			return -1;
		}

		data += attrlen;
		length -= attrlen;
	}

	return 0;
}


/** See if the data pointed to by PTR is a valid RADIUS packet.
 *
 * Packet is not 'const * const' because we may update data_len, if there's more data
 * in the UDP packet than in the RADIUS packet.
 *
 * @param packet to check
 * @param flags to control decoding
 * @param reason if not NULL, will have the failure reason written to where it points.
 * @return
 *	- True on success.
 *	- False on failure.
 */
bool rad_packet_ok(RADIUS_PACKET *packet, int flags, decode_fail_t *reason)
{
	uint8_t			*attr;
	size_t			totallen;
	int			count;
	radius_packet_t		*hdr;
	char			host_ipaddr[128];
	bool			require_ma = false;
	bool			seen_ma = false;
	uint32_t		num_attributes;
	decode_fail_t		failure = DECODE_FAIL_NONE;

	/*
	 *	Check for packets smaller than the packet header.
	 *
	 *	RFC 2865, Section 3., subsection 'length' says:
	 *
	 *	"The minimum length is 20 ..."
	 */
	if (packet->data_len < RADIUS_HDR_LEN) {
		FR_DEBUG_STRERROR_PRINTF("Malformed RADIUS packet from host %s: too short (received %zu < minimum %d)",
			   inet_ntop(packet->src_ipaddr.af,
				     &packet->src_ipaddr.ipaddr,
				     host_ipaddr, sizeof(host_ipaddr)),
				     packet->data_len, RADIUS_HDR_LEN);
		failure = DECODE_FAIL_MIN_LENGTH_PACKET;
		goto finish;
	}


	/*
	 *	Check for packets with mismatched size.
	 *	i.e. We've received 128 bytes, and the packet header
	 *	says it's 256 bytes long.
	 */
	totallen = (packet->data[2] << 8) | packet->data[3];
	hdr = (radius_packet_t *)packet->data;

	/*
	 *	Code of 0 is not understood.
	 *	Code of 16 or greate is not understood.
	 */
	if ((hdr->code == 0) ||
	    (hdr->code >= FR_MAX_PACKET_CODE)) {
		FR_DEBUG_STRERROR_PRINTF("Bad RADIUS packet from host %s: unknown packet code %d",
			   inet_ntop(packet->src_ipaddr.af,
				     &packet->src_ipaddr.ipaddr,
				     host_ipaddr, sizeof(host_ipaddr)),
			   hdr->code);
		failure = DECODE_FAIL_UNKNOWN_PACKET_CODE;
		goto finish;
	}

	/*
	 *	Message-Authenticator is required in Status-Server
	 *	packets, otherwise they can be trivially forged.
	 */
	if (hdr->code == PW_CODE_STATUS_SERVER) require_ma = true;

	/*
	 *	It's also required if the caller asks for it.
	 */
	if (flags) require_ma = true;

	/*
	 *	Repeat the length checks.  This time, instead of
	 *	looking at the data we received, look at the value
	 *	of the 'length' field inside of the packet.
	 *
	 *	Check for packets smaller than the packet header.
	 *
	 *	RFC 2865, Section 3., subsection 'length' says:
	 *
	 *	"The minimum length is 20 ..."
	 */
	if (totallen < RADIUS_HDR_LEN) {
		FR_DEBUG_STRERROR_PRINTF("Malformed RADIUS packet from host %s: too short (length %zu < minimum %d)",
			   inet_ntop(packet->src_ipaddr.af,
				     &packet->src_ipaddr.ipaddr,
				     host_ipaddr, sizeof(host_ipaddr)),
				     totallen, RADIUS_HDR_LEN);
		failure = DECODE_FAIL_MIN_LENGTH_FIELD;
		goto finish;
	}

	/*
	 *	And again, for the value of the 'length' field.
	 *
	 *	RFC 2865, Section 3., subsection 'length' says:
	 *
	 *	" ... and maximum length is 4096."
	 *
	 *	HOWEVER.  This requirement is for the network layer.
	 *	If the code gets here, we assume that a well-formed
	 *	packet is an OK packet.
	 *
	 *	We allow both the UDP data length, and the RADIUS
	 *	"length" field to contain up to 64K of data.
	 */

	/*
	 *	RFC 2865, Section 3., subsection 'length' says:
	 *
	 *	"If the packet is shorter than the Length field
	 *	indicates, it MUST be silently discarded."
	 *
	 *	i.e. No response to the NAS.
	 */
	if (packet->data_len < totallen) {
		FR_DEBUG_STRERROR_PRINTF("Malformed RADIUS packet from host %s: received %zu octets, packet length says %zu",
			   inet_ntop(packet->src_ipaddr.af,
				     &packet->src_ipaddr.ipaddr,
				     host_ipaddr, sizeof(host_ipaddr)),
				     packet->data_len, totallen);
		failure = DECODE_FAIL_MIN_LENGTH_MISMATCH;
		goto finish;
	}

	/*
	 *	RFC 2865, Section 3., subsection 'length' says:
	 *
	 *	"Octets outside the range of the Length field MUST be
	 *	treated as padding and ignored on reception."
	 */
	if (packet->data_len > totallen) {
		/*
		 *	We're shortening the packet below, but just
		 *	to be paranoid, zero out the extra data.
		 */
		memset(packet->data + totallen, 0, packet->data_len - totallen);
		packet->data_len = totallen;
	}

	/*
	 *	Walk through the packet's attributes, ensuring that
	 *	they add up EXACTLY to the size of the packet.
	 *
	 *	If they don't, then the attributes either under-fill
	 *	or over-fill the packet.  Any parsing of the packet
	 *	is impossible, and will result in unknown side effects.
	 *
	 *	This would ONLY happen with buggy RADIUS implementations,
	 *	or with an intentional attack.  Either way, we do NOT want
	 *	to be vulnerable to this problem.
	 */
	attr = hdr->data;
	count = totallen - RADIUS_HDR_LEN;
	num_attributes = 0;

	while (count > 0) {
		/*
		 *	We need at least 2 bytes to check the
		 *	attribute header.
		 */
		if (count < 2) {
			FR_DEBUG_STRERROR_PRINTF("Malformed RADIUS packet from host %s: attribute header overflows the packet",
				   inet_ntop(packet->src_ipaddr.af,
					     &packet->src_ipaddr.ipaddr,
					     host_ipaddr, sizeof(host_ipaddr)));
			failure = DECODE_FAIL_HEADER_OVERFLOW;
			goto finish;
		}

		/*
		 *	Attribute number zero is NOT defined.
		 */
		if (attr[0] == 0) {
			FR_DEBUG_STRERROR_PRINTF("Malformed RADIUS packet from host %s: Invalid attribute 0",
				   inet_ntop(packet->src_ipaddr.af,
					     &packet->src_ipaddr.ipaddr,
					     host_ipaddr, sizeof(host_ipaddr)));
			failure = DECODE_FAIL_INVALID_ATTRIBUTE;
			goto finish;
		}

		/*
		 *	Attributes are at LEAST as long as the ID & length
		 *	fields.  Anything shorter is an invalid attribute.
		 */
		if (attr[1] < 2) {
			FR_DEBUG_STRERROR_PRINTF("Malformed RADIUS packet from host %s: attribute %u too short",
				   inet_ntop(packet->src_ipaddr.af,
					     &packet->src_ipaddr.ipaddr,
					     host_ipaddr, sizeof(host_ipaddr)),
				   attr[0]);
			failure = DECODE_FAIL_ATTRIBUTE_TOO_SHORT;
			goto finish;
		}

		/*
		 *	If there are fewer bytes in the packet than in the
		 *	attribute, it's a bad packet.
		 */
		if (count < attr[1]) {
			FR_DEBUG_STRERROR_PRINTF("Malformed RADIUS packet from host %s: attribute %u data overflows the packet",
				   inet_ntop(packet->src_ipaddr.af,
					     &packet->src_ipaddr.ipaddr,
					     host_ipaddr, sizeof(host_ipaddr)),
					   attr[0]);
			failure = DECODE_FAIL_ATTRIBUTE_OVERFLOW;
			goto finish;
		}

		/*
		 *	Sanity check the attributes for length.
		 */
		switch (attr[0]) {
		default:	/* don't do anything by default */
			break;

			/*
			 *	If there's an EAP-Message, we require
			 *	a Message-Authenticator.
			 */
		case PW_EAP_MESSAGE:
			require_ma = true;
			break;

		case PW_MESSAGE_AUTHENTICATOR:
			if (attr[1] != 2 + AUTH_VECTOR_LEN) {
				FR_DEBUG_STRERROR_PRINTF("Malformed RADIUS packet from host %s: Message-Authenticator has invalid length %d",
					   inet_ntop(packet->src_ipaddr.af,
						     &packet->src_ipaddr.ipaddr,
						     host_ipaddr, sizeof(host_ipaddr)),
					   attr[1] - 2);
				failure = DECODE_FAIL_MA_INVALID_LENGTH;
				goto finish;
			}
			seen_ma = true;
			break;
		}

		/*
		 *	FIXME: Look up the base 255 attributes in the
		 *	dictionary, and switch over their type.  For
		 *	integer/date/ip, the attribute length SHOULD
		 *	be 6.
		 */
		count -= attr[1];	/* grab the attribute length */
		attr += attr[1];
		num_attributes++;	/* seen one more attribute */
	}

	/*
	 *	If the attributes add up to a packet, it's allowed.
	 *
	 *	If not, we complain, and throw the packet away.
	 */
	if (count != 0) {
		FR_DEBUG_STRERROR_PRINTF("Malformed RADIUS packet from host %s: packet attributes do NOT exactly fill the packet",
			   inet_ntop(packet->src_ipaddr.af,
				     &packet->src_ipaddr.ipaddr,
				     host_ipaddr, sizeof(host_ipaddr)));
		failure = DECODE_FAIL_ATTRIBUTE_UNDERFLOW;
		goto finish;
	}

	/*
	 *	If we're configured to look for a maximum number of
	 *	attributes, and we've seen more than that maximum,
	 *	then throw the packet away, as a possible DoS.
	 */
	if ((fr_max_attributes > 0) &&
	    (num_attributes > fr_max_attributes)) {
		FR_DEBUG_STRERROR_PRINTF("Possible DoS attack from host %s: Too many attributes in request (received %d, max %d are allowed).",
			   inet_ntop(packet->src_ipaddr.af,
				     &packet->src_ipaddr.ipaddr,
				     host_ipaddr, sizeof(host_ipaddr)),
			   num_attributes, fr_max_attributes);
		failure = DECODE_FAIL_TOO_MANY_ATTRIBUTES;
		goto finish;
	}

	/*
	 * 	http://www.freeradius.org/rfc/rfc2869.html#EAP-Message
	 *
	 *	A packet with an EAP-Message attribute MUST also have
	 *	a Message-Authenticator attribute.
	 *
	 *	A Message-Authenticator all by itself is OK, though.
	 *
	 *	Similarly, Status-Server packets MUST contain
	 *	Message-Authenticator attributes.
	 */
	if (require_ma && !seen_ma) {
		FR_DEBUG_STRERROR_PRINTF("Insecure packet from host %s:  Packet does not contain required Message-Authenticator attribute",
			   inet_ntop(packet->src_ipaddr.af,
				     &packet->src_ipaddr.ipaddr,
				     host_ipaddr, sizeof(host_ipaddr)));
		failure = DECODE_FAIL_MA_MISSING;
		goto finish;
	}

	/*
	 *	Fill RADIUS header fields
	 */
	packet->code = hdr->code;
	packet->id = hdr->id;
	memcpy(packet->vector, hdr->vector, AUTH_VECTOR_LEN);


	finish:

	if (reason) {
		*reason = failure;
	}
	return (failure == DECODE_FAIL_NONE);
}


/** Receive UDP client requests, and fill in the basics of a RADIUS_PACKET structure
 *
 */
RADIUS_PACKET *rad_recv(TALLOC_CTX *ctx, int fd, int flags)
{
	int sock_flags = 0;
	ssize_t data_len;
	RADIUS_PACKET		*packet;

	/*
	 *	Allocate the new request data structure
	 */
	packet = rad_alloc(ctx, false);
	if (!packet) {
		fr_strerror_printf("out of memory");
		return NULL;
	}

	if (flags & 0x02) {
		sock_flags = MSG_PEEK;
		flags &= ~0x02;
	}

	data_len = rad_recvfrom(fd, packet, sock_flags,
				&packet->src_ipaddr, &packet->src_port,
				&packet->dst_ipaddr, &packet->dst_port);

	/*
	 *	Check for socket errors.
	 */
	if (data_len < 0) {
		FR_DEBUG_STRERROR_PRINTF("Error receiving packet: %s", fr_syserror(errno));
		/* packet->data is NULL */
		rad_free(&packet);
		return NULL;
	}
	packet->data_len = data_len; /* unsigned vs signed */

	/*
	 *	If the packet is too big, then rad_recvfrom did NOT
	 *	allocate memory.  Instead, it just discarded the
	 *	packet.
	 */
	if (packet->data_len > MAX_PACKET_LEN) {
		FR_DEBUG_STRERROR_PRINTF("Discarding packet: Larger than RFC limitation of 4096 bytes");
		/* packet->data is NULL */
		rad_free(&packet);
		return NULL;
	}

	/*
	 *	Read no data.  Continue.
	 *	This check is AFTER the MAX_PACKET_LEN check above, because
	 *	if the packet is larger than MAX_PACKET_LEN, we also have
	 *	packet->data == NULL
	 */
	if ((packet->data_len == 0) || !packet->data) {
		FR_DEBUG_STRERROR_PRINTF("Empty packet: Socket is not ready");
		rad_free(&packet);
		return NULL;
	}

	/*
	 *	See if it's a well-formed RADIUS packet.
	 */
	if (!rad_packet_ok(packet, flags, NULL)) {
		rad_free(&packet);
		return NULL;
	}

	/*
	 *	Remember which socket we read the packet from.
	 */
	packet->sockfd = fd;

	/*
	 *	FIXME: Do even more filtering by only permitting
	 *	certain IP's.  The problem is that we don't know
	 *	how to do this properly for all possible clients...
	 */

	/*
	 *	Explicitely set the VP list to empty.
	 */
	packet->vps = NULL;

#ifndef NDEBUG
	if ((fr_debug_lvl > 3) && fr_log_fp) rad_print_hex(packet);
#endif

	return packet;
}


/** Verify the Request/Response Authenticator (and Message-Authenticator if present) of a packet
 *
 */
int rad_verify(RADIUS_PACKET *packet, RADIUS_PACKET *original, char const *secret)
{
	uint8_t		*ptr;
	int		length;
	int		attrlen;
	int		rcode;
	char		buffer[32];

	if (!packet || !packet->data) return -1;

	/*
	 *	Before we allocate memory for the attributes, do more
	 *	sanity checking.
	 */
	ptr = packet->data + RADIUS_HDR_LEN;
	length = packet->data_len - RADIUS_HDR_LEN;
	while (length > 0) {
		uint8_t	msg_auth_vector[AUTH_VECTOR_LEN];
		uint8_t calc_auth_vector[AUTH_VECTOR_LEN];

		attrlen = ptr[1];

		switch (ptr[0]) {
		default:	/* don't do anything. */
			break;

			/*
			 *	Note that more than one Message-Authenticator
			 *	attribute is invalid.
			 */
		case PW_MESSAGE_AUTHENTICATOR:
			memcpy(msg_auth_vector, &ptr[2], sizeof(msg_auth_vector));
			memset(&ptr[2], 0, AUTH_VECTOR_LEN);

			switch (packet->code) {
			default:
				break;

			case PW_CODE_ACCOUNTING_RESPONSE:
				if (original &&
				    (original->code == PW_CODE_STATUS_SERVER)) {
					goto do_ack;
				}

			case PW_CODE_ACCOUNTING_REQUEST:
			case PW_CODE_DISCONNECT_REQUEST:
			case PW_CODE_COA_REQUEST:
				memset(packet->data + 4, 0, AUTH_VECTOR_LEN);
				break;

			do_ack:
			case PW_CODE_ACCESS_ACCEPT:
			case PW_CODE_ACCESS_REJECT:
			case PW_CODE_ACCESS_CHALLENGE:
			case PW_CODE_DISCONNECT_ACK:
			case PW_CODE_DISCONNECT_NAK:
			case PW_CODE_COA_ACK:
			case PW_CODE_COA_NAK:
				if (!original) {
					fr_strerror_printf("Cannot validate Message-Authenticator in response "
							   "packet without a request packet");
					return -1;
				}
				memcpy(packet->data + 4, original->vector, AUTH_VECTOR_LEN);
				break;
			}

			fr_hmac_md5(calc_auth_vector, packet->data, packet->data_len,
				    (uint8_t const *) secret, strlen(secret));
			if (rad_digest_cmp(calc_auth_vector, msg_auth_vector,
				   sizeof(calc_auth_vector)) != 0) {
				fr_strerror_printf("Received packet from %s with invalid Message-Authenticator!  "
						   "(Shared secret is incorrect.)",
						   inet_ntop(packet->src_ipaddr.af,
							     &packet->src_ipaddr.ipaddr,
							     buffer, sizeof(buffer)));
				/* Silently drop packet, according to RFC 3579 */
				return -1;
			} /* else the message authenticator was good */

			/*
			 *	Reinitialize Authenticators.
			 */
			memcpy(&ptr[2], msg_auth_vector, AUTH_VECTOR_LEN);
			memcpy(packet->data + 4, packet->vector, AUTH_VECTOR_LEN);
			break;
		} /* switch over the attributes */

		ptr += attrlen;
		length -= attrlen;
	} /* loop over the packet, sanity checking the attributes */

	/*
	 *	It looks like a RADIUS packet, but we don't know what it is
	 *	so can't validate the authenticators.
	 */
	if ((packet->code == 0) || (packet->code >= FR_MAX_PACKET_CODE)) {
		fr_strerror_printf("Received Unknown packet code %d "
				   "from client %s port %d: Cannot validate Request/Response Authenticator.",
				   packet->code,
				   inet_ntop(packet->src_ipaddr.af,
				             &packet->src_ipaddr.ipaddr,
				             buffer, sizeof(buffer)),
				   packet->src_port);
		return -1;
	}

	/*
	 *	Calculate and/or verify Request or Response Authenticator.
	 */
	switch (packet->code) {
	case PW_CODE_ACCESS_REQUEST:
	case PW_CODE_STATUS_SERVER:
		/*
		 *	The authentication vector is random
		 *	nonsense, invented by the client.
		 */
		break;

	case PW_CODE_COA_REQUEST:
	case PW_CODE_DISCONNECT_REQUEST:
	case PW_CODE_ACCOUNTING_REQUEST:
		if (calc_acctdigest(packet, secret) > 1) {
			fr_strerror_printf("Received %s packet "
					   "from client %s with invalid Request Authenticator!  "
					   "(Shared secret is incorrect.)",
					   fr_packet_codes[packet->code],
					   inet_ntop(packet->src_ipaddr.af,
						     &packet->src_ipaddr.ipaddr,
						     buffer, sizeof(buffer)));
			return -1;
		}
		break;

		/* Verify the reply digest */
	case PW_CODE_ACCESS_ACCEPT:
	case PW_CODE_ACCESS_REJECT:
	case PW_CODE_ACCESS_CHALLENGE:
	case PW_CODE_ACCOUNTING_RESPONSE:
	case PW_CODE_DISCONNECT_ACK:
	case PW_CODE_DISCONNECT_NAK:
	case PW_CODE_COA_ACK:
	case PW_CODE_COA_NAK:
		rcode = calc_replydigest(packet, original, secret);
		if (rcode > 1) {
			fr_strerror_printf("Received %s packet "
					   "from home server %s port %d with invalid Response Authenticator!  "
					   "(Shared secret is incorrect.)",
					   fr_packet_codes[packet->code],
					   inet_ntop(packet->src_ipaddr.af,
						     &packet->src_ipaddr.ipaddr,
						     buffer, sizeof(buffer)),
					   packet->src_port);
			return -1;
		}
		break;

	default:
		fr_strerror_printf("Received Unknown packet code %d "
				   "from client %s port %d: Cannot validate Request/Response Authenticator",
				   packet->code,
				   inet_ntop(packet->src_ipaddr.af,
				             &packet->src_ipaddr.ipaddr,
				             buffer, sizeof(buffer)),
				   packet->src_port);
		return -1;
	}

	return 0;
}


/** Convert a "concatenated" attribute to one long VP
 *
 */
static ssize_t data2vp_concat(TALLOC_CTX *ctx,
			      DICT_ATTR const *da, uint8_t const *start,
			      size_t const packetlen, VALUE_PAIR **pvp)
{
	size_t total;
	uint8_t attr;
	uint8_t const *ptr = start;
	uint8_t const *end = start + packetlen;
	uint8_t *p;
	VALUE_PAIR *vp;

	total = 0;
	attr = ptr[0];

	/*
	 *	The packet has already been sanity checked, so we
	 *	don't care about walking off of the end of it.
	 */
	while (ptr < end) {
		total += ptr[1] - 2;

		ptr += ptr[1];

		/*
		 *	Attributes MUST be consecutive.
		 */
		if (ptr[0] != attr) break;
	}

	vp = pairalloc(ctx, da);
	if (!vp) return -1;

	vp->vp_length = total;
	vp->vp_octets = p = talloc_array(vp, uint8_t, vp->vp_length);
	if (!p) {
		pairfree(&vp);
		return -1;
	}

	total = 0;
	ptr = start;
	while (total < vp->vp_length) {
		memcpy(p, ptr + 2, ptr[1] - 2);
		p += ptr[1] - 2;
		total += ptr[1] - 2;
		ptr += ptr[1];
	}

	*pvp = vp;
	return ptr - start;
}


/** Convert TLVs to one or more VPs
 *
 */
static ssize_t data2vp_tlvs(TALLOC_CTX *ctx,
			    RADIUS_PACKET *packet, RADIUS_PACKET const *original,
			    char const *secret, DICT_ATTR const *da,
			    uint8_t const *start, size_t length,
			    VALUE_PAIR **pvp)
{
	uint8_t const *data = start;
	DICT_ATTR const *child;
	VALUE_PAIR *head, **tail;

	if (length < 3) return -1; /* type, length, value */

	VP_HEXDUMP("tlvs", data, length);

	if (rad_tlv_ok(data, length, 1, 1) < 0) return -1;

	head = NULL;
	tail = &head;

	while (data < (start + length)) {
		ssize_t tlv_len;

		child = dict_attrbyparent(da, data[0], da->vendor);
		if (!child) {
			unsigned int my_attr, my_vendor;

			VP_TRACE("Failed to find child %u of TLV %s\n",
				 data[0], da->name);

			/*
			 *	Get child attr/vendor so that
			 *	we can call unknown attr.
			 */
			my_attr = data[0];
			my_vendor = da->vendor;

			if (!dict_attr_child(da, &my_attr, &my_vendor)) {
				pairfree(&head);
				return -1;
			}

			child = dict_unknown_afrom_fields(ctx, my_attr, my_vendor);
			if (!child) {
				pairfree(&head);
				return -1;
			}
		}

		tlv_len = data2vp(ctx, packet, original, secret, child,
				  data + 2, data[1] - 2, data[1] - 2, tail);
		if (tlv_len < 0) {
			pairfree(&head);
			return -1;
		}
		if (*tail) tail = &((*tail)->next);
		data += data[1];
	}

	*pvp = head;
	return length;
}

/** Convert a top-level VSA to a VP.
 *
 * "length" can be LONGER than just this sub-vsa.
 */
static ssize_t data2vp_vsa(TALLOC_CTX *ctx, RADIUS_PACKET *packet,
			   RADIUS_PACKET const *original,
			   char const *secret, DICT_VENDOR *dv,
			   uint8_t const *data, size_t length,
			   VALUE_PAIR **pvp)
{
	unsigned int attribute;
	ssize_t attrlen, my_len;
	DICT_ATTR const *da;

	VP_TRACE("data2vp_vsa: length %u\n", (unsigned int) length);

#ifndef NDEBUG
	if (length <= (dv->type + dv->length)) {
		fr_strerror_printf("data2vp_vsa: Failure to call rad_tlv_ok");
		return -1;
	}
#endif

	switch (dv->type) {
	case 4:
		/* data[0] must be zero */
		attribute = data[1] << 16;
		attribute |= data[2] << 8;
		attribute |= data[3];
		break;

	case 2:
		attribute = data[0] << 8;
		attribute |= data[1];
		break;

	case 1:
		attribute = data[0];
		break;

	default:
		fr_strerror_printf("data2vp_vsa: Internal sanity check failed");
		return -1;
	}

	switch (dv->length) {
	case 2:
		/* data[dv->type] must be zero, from rad_tlv_ok() */
		attrlen = data[dv->type + 1];
		break;

	case 1:
		attrlen = data[dv->type];
		break;

	case 0:
		attrlen = length;
		break;

	default:
		fr_strerror_printf("data2vp_vsa: Internal sanity check failed");
		return -1;
	}

	/*
	 *	See if the VSA is known.
	 */
	da = dict_attrbyvalue(attribute, dv->vendorpec);
	if (!da) da = dict_unknown_afrom_fields(ctx, attribute, dv->vendorpec);
	if (!da) return -1;

	my_len = data2vp(ctx, packet, original, secret, da,
			 data + dv->type + dv->length,
			 attrlen - (dv->type + dv->length),
			 attrlen - (dv->type + dv->length),
			 pvp);
	if (my_len < 0) return my_len;

	return attrlen;
}


/** Convert a fragmented extended attr to a VP
 *
 * Format is:
 *
 * attr
 * length
 * extended-attr
 * flag
 * data...
 *
 * But for the first fragment, we get passed a pointer to the "extended-attr"
 */
static ssize_t data2vp_extended(TALLOC_CTX *ctx, RADIUS_PACKET *packet,
				RADIUS_PACKET const *original,
				char const *secret, DICT_ATTR const *da,
				uint8_t const *data,
				size_t attrlen, size_t packetlen,
				VALUE_PAIR **pvp)
{
	ssize_t rcode;
	size_t fraglen;
	uint8_t *head, *tail;
	uint8_t const *frag, *end;
	uint8_t const *attr;
	int fragments;
	bool last_frag;

	if (attrlen < 3) return -1;

	/*
	 *	Calculate the length of all of the fragments.  For
	 *	now, they MUST be contiguous in the packet, and they
	 *	MUST be all of the same TYPE and EXTENDED-TYPE
	 */
	attr = data - 2;
	fraglen = attrlen - 2;
	frag = data + attrlen;
	end = data + packetlen;
	fragments = 1;
	last_frag = false;

	while (frag < end) {
		if (last_frag ||
		    (frag[0] != attr[0]) ||
		    (frag[1] < 4) ||		       /* too short for long-extended */
		    (frag[2] != attr[2]) ||
		    ((frag + frag[1]) > end)) {		/* overflow */
			end = frag;
			break;
		}

		last_frag = ((frag[3] & 0x80) == 0);

		fraglen += frag[1] - 4;
		frag += frag[1];
		fragments++;
	}

	head = tail = malloc(fraglen);
	if (!head) return -1;

	VP_TRACE("Fragments %d, total length %d\n", fragments, (int) fraglen);

	/*
	 *	And again, but faster and looser.
	 *
	 *	We copy the first fragment, followed by the rest of
	 *	the fragments.
	 */
	frag = attr;

	while (fragments >  0) {
		memcpy(tail, frag + 4, frag[1] - 4);
		tail += frag[1] - 4;
		frag += frag[1];
		fragments--;
	}

	VP_HEXDUMP("long-extended fragments", head, fraglen);

	rcode = data2vp(ctx, packet, original, secret, da,
			head, fraglen, fraglen, pvp);
	free(head);
	if (rcode < 0) return rcode;

	return end - data;
}

/** Convert a Vendor-Specific WIMAX to vps
 *
 * @note Called ONLY for Vendor-Specific
 */
static ssize_t data2vp_wimax(TALLOC_CTX *ctx,
			     RADIUS_PACKET *packet, RADIUS_PACKET const *original,
			     char const *secret, uint32_t vendor,
			     uint8_t const *data,
			     size_t attrlen, size_t packetlen,
			     VALUE_PAIR **pvp)
{
	ssize_t rcode;
	size_t fraglen;
	bool last_frag;
	uint8_t *head, *tail;
	uint8_t const *frag, *end;
	DICT_ATTR const *child;

	if (attrlen < 8) return -1;

	if (((size_t) (data[5] + 4)) != attrlen) return -1;

	child = dict_attrbyvalue(data[4], vendor);
	if (!child) return -1;

	if ((data[6] & 0x80) == 0) {
		rcode = data2vp(ctx, packet, original, secret, child,
				data + 7, data[5] - 3, data[5] - 3,
				pvp);
		if (rcode < 0) return -1;
		return 7 + rcode;
	}

	/*
	 *	Calculate the length of all of the fragments.  For
	 *	now, they MUST be contiguous in the packet, and they
	 *	MUST be all of the same VSA, WiMAX, and WiMAX-attr.
	 *
	 *	The first fragment doesn't have a RADIUS attribute
	 *	header, so it needs to be treated a little special.
	 */
	fraglen = data[5] - 3;
	frag = data + attrlen;
	end = data + packetlen;
	last_frag = false;

	while (frag < end) {
		if (last_frag ||
		    (frag[0] != PW_VENDOR_SPECIFIC) ||
		    (frag[1] < 9) ||		       /* too short for wimax */
		    ((frag + frag[1]) > end) ||		/* overflow */
		    (memcmp(frag + 2, data, 4) != 0) || /* not wimax */
		    (frag[6] != data[4]) || /* not the same wimax attr */
		    ((frag[7] + 6) != frag[1])) { /* doesn't fill the attr */
			end = frag;
			break;
		}

		last_frag = ((frag[8] & 0x80) == 0);

		fraglen += frag[7] - 3;
		frag += frag[1];
	}

	head = tail = malloc(fraglen);
	if (!head) return -1;

	/*
	 *	And again, but faster and looser.
	 *
	 *	We copy the first fragment, followed by the rest of
	 *	the fragments.
	 */
	frag = data;

	memcpy(tail, frag + 4 + 3, frag[4 + 1] - 3);
	tail += frag[4 + 1] - 3;
	frag += attrlen;	/* should be frag[1] - 7 */

	/*
	 *	frag now points to RADIUS attributes
	 */
	do {
		memcpy(tail, frag + 2 + 4 + 3, frag[2 + 4 + 1] - 3);
		tail += frag[2 + 4 + 1] - 3;
		frag += frag[1];
	} while (frag < end);

	VP_HEXDUMP("wimax fragments", head, fraglen);

	rcode = data2vp(ctx, packet, original, secret, child,
			head, fraglen, fraglen, pvp);
	free(head);
	if (rcode < 0) return rcode;

	return end - data;
}


/** Convert a top-level VSA to one or more VPs
 *
 */
static ssize_t data2vp_vsas(TALLOC_CTX *ctx, RADIUS_PACKET *packet,
			    RADIUS_PACKET const *original,
			    char const *secret, uint8_t const *data,
			    size_t attrlen, size_t packetlen,
			    VALUE_PAIR **pvp)
{
	size_t total;
	ssize_t rcode;
	uint32_t vendor;
	DICT_VENDOR *dv;
	VALUE_PAIR *head, **tail;
	DICT_VENDOR my_dv;

	if (attrlen > packetlen) return -1;
	if (attrlen < 5) return -1; /* vid, value */
	if (data[0] != 0) return -1; /* we require 24-bit VIDs */

	VP_TRACE("data2vp_vsas\n");

	memcpy(&vendor, data, 4);
	vendor = ntohl(vendor);
	dv = dict_vendorbyvalue(vendor);
	if (!dv) {
		/*
		 *	RFC format is 1 octet type, 1 octet length
		 */
		if (rad_tlv_ok(data + 4, attrlen - 4, 1, 1) < 0) {
			VP_TRACE("data2vp_vsas: unknown tlvs not OK: %s\n", fr_strerror());
			return -1;
		}

		/*
		 *	It's a known unknown.
		 */
		memset(&my_dv, 0, sizeof(my_dv));
		dv = &my_dv;

		/*
		 *	Fill in the fields.  Note that the name is empty!
		 */
		dv->vendorpec = vendor;
		dv->type = 1;
		dv->length = 1;

		goto create_attrs;
	}

	/*
	 *	WiMAX craziness
	 */
	if ((vendor == VENDORPEC_WIMAX) && dv->flags) {
		rcode = data2vp_wimax(ctx, packet, original, secret, vendor,
				      data, attrlen, packetlen, pvp);
		return rcode;
	}

	/*
	 *	VSAs should normally be in TLV format.
	 */
	if (rad_tlv_ok(data + 4, attrlen - 4,
		       dv->type, dv->length) < 0) {
		VP_TRACE("data2vp_vsas: tlvs not OK: %s\n", fr_strerror());
		return -1;
	}

	/*
	 *	There may be more than one VSA in the
	 *	Vendor-Specific.  If so, loop over them all.
	 */
create_attrs:
	data += 4;
	attrlen -= 4;
	packetlen -= 4;
	total = 4;
	head = NULL;
	tail = &head;

	while (attrlen > 0) {
		ssize_t vsa_len;

		vsa_len = data2vp_vsa(ctx, packet, original, secret, dv,
				      data, attrlen, tail);
		if (vsa_len < 0) {
			pairfree(&head);
			fr_strerror_printf("Internal sanity check %d", __LINE__);
			return -1;
		}

		/*
		 *	Vendors can send zero-length VSAs.
		 */
		if (*tail) tail = &((*tail)->next);

		data += vsa_len;
		attrlen -= vsa_len;
		packetlen -= vsa_len;
		total += vsa_len;
	}

	*pvp = head;
	return total;
}

/** Create any kind of VP from the attribute contents
 *
 * "length" is AT LEAST the length of this attribute, as we
 * expect the caller to have verified the data with
 * rad_packet_ok().  "length" may be up to the length of the
 * packet.
 *
 * @return
 *	- Length on success.
 *	- -1 on failure.
 */
ssize_t data2vp(TALLOC_CTX *ctx,
		RADIUS_PACKET *packet, RADIUS_PACKET const *original,
		char const *secret,
		DICT_ATTR const *da, uint8_t const *start,
		size_t const attrlen, size_t const packetlen,
		VALUE_PAIR **pvp)
{
	int8_t tag = TAG_NONE;
	size_t datalen;
	ssize_t rcode;
	uint32_t vendor;
	DICT_ATTR const *child;
	VALUE_PAIR *vp;
	uint8_t const *data = start;
	char *p;
	uint8_t buffer[256];

	/*
	 *	FIXME: Attrlen can be larger than 253 for extended attrs!
	 */
	if (!da || (attrlen > packetlen) ||
	    ((attrlen > 253) && (attrlen != packetlen)) ||
	    (attrlen > 128*1024)) {
		fr_strerror_printf("data2vp: invalid arguments");
		return -1;
	}

	VP_HEXDUMP("data2vp", start, attrlen);

	VP_TRACE("parent %s len %zu ... %zu\n", da->name, attrlen, packetlen);

	datalen = attrlen;

	/*
	 *	Hacks for CUI.  The WiMAX spec says that it can be
	 *	zero length, even though this is forbidden by the
	 *	RADIUS specs.  So... we make a special case for it.
	 */
	if (attrlen == 0) {
		if (!((da->vendor == 0) &&
		      (da->attr == PW_CHARGEABLE_USER_IDENTITY))) {
			*pvp = NULL;
			return 0;
		}

#ifndef NDEBUG
		/*
		 *	Hacks for Coverity.  Editing the dictionary
		 *	will break assumptions about CUI.  We know
		 *	this, but Coverity doesn't.
		 */
		if (da->type != PW_TYPE_OCTETS) return -1;
#endif

		data = NULL;
		datalen = 0;
		goto alloc_cui;	/* skip everything */
	}

	/*
	 *	Hacks for tags.  If the attribute is capable of
	 *	encoding a tag, and there's room for the tag, and
	 *	there is a tag, or it's encrypted with Tunnel-Password,
	 *	then decode the tag.
	 */
	if (da->flags.has_tag && (datalen > 1) &&
	    ((data[0] < 0x20) ||
	     (da->flags.encrypt == FLAG_ENCRYPT_TUNNEL_PASSWORD))) {
		/*
		 *	Only "short" attributes can be encrypted.
		 */
		if (datalen >= sizeof(buffer)) return -1;

		if (da->type == PW_TYPE_STRING) {
			memcpy(buffer, data + 1, datalen - 1);
			tag = data[0];
			datalen -= 1;

		} else if (da->type == PW_TYPE_INTEGER) {
			memcpy(buffer, data, attrlen);
			tag = buffer[0];
			buffer[0] = 0;

		} else {
			return -1; /* only string and integer can have tags */
		}

		data = buffer;
	}

	/*
	 *	Decrypt the attribute.
	 */
	if (secret && packet && (da->flags.encrypt != FLAG_ENCRYPT_NONE)) {
		VP_TRACE("data2vp: decrypting type %u\n", da->flags.encrypt);
		/*
		 *	Encrypted attributes can only exist for the
		 *	old-style format.  Extended attributes CANNOT
		 *	be encrypted.
		 */
		if (attrlen > 253) {
			return -1;
		}

		if (data == start) {
			memcpy(buffer, data, attrlen);
		}
		data = buffer;

		switch (da->flags.encrypt) { /* can't be tagged */
		/*
		 *  User-Password
		 */
		case FLAG_ENCRYPT_USER_PASSWORD:
			if (original) {
				rad_pwdecode((char *) buffer,
					     attrlen, secret,
					     original->vector);
			} else {
				rad_pwdecode((char *) buffer,
					     attrlen, secret,
					     packet->vector);
			}
			buffer[253] = '\0';

			/*
			 *	Take off trailing zeros from the END.
			 *	This allows passwords to have zeros in
			 *	the middle of a field.
			 *
			 *	However, if the password has a zero at
			 *	the end, it will get mashed by this
			 *	code.  There's really no way around
			 *	that.
			 */
			while ((datalen > 0) && (buffer[datalen - 1] == '\0')) datalen--;
			break;

		/*
		 *	Tunnel-Password's may go ONLY in response
		 *	packets.  They can have a tag, so datalen is
		 *	not the same as attrlen.
		 */
		case FLAG_ENCRYPT_TUNNEL_PASSWORD:
			if (rad_tunnel_pwdecode(buffer, &datalen, secret,
						original ? original->vector : nullvector) < 0) {
				goto raw;
			}
			break;

		/*
		 *  Ascend-Send-Secret
		 *  Ascend-Receive-Secret
		 */
		case FLAG_ENCRYPT_ASCEND_SECRET:
			if (!original) {
				goto raw;
			} else {
				uint8_t my_digest[AUTH_VECTOR_LEN];
				make_secret(my_digest,
					    original->vector,
					    secret, data);
				memcpy(buffer, my_digest,
				       AUTH_VECTOR_LEN );
				buffer[AUTH_VECTOR_LEN] = '\0';
				datalen = strlen((char *) buffer);
			}
			break;

		default:
			break;
		} /* switch over encryption flags */
	}

	/*
	 *	Double-check the length after decrypting the
	 *	attribute.
	 */
	VP_TRACE("data2vp: type %u\n", da->type);
	switch (da->type) {
	case PW_TYPE_STRING:
	case PW_TYPE_OCTETS:
		break;

	case PW_TYPE_ABINARY:
		if (datalen > sizeof(vp->vp_filter)) goto raw;
		break;

	case PW_TYPE_INTEGER:
	case PW_TYPE_IPV4_ADDR:
	case PW_TYPE_DATE:
	case PW_TYPE_SIGNED:
		if (datalen != 4) goto raw;
		break;

	case PW_TYPE_INTEGER64:
	case PW_TYPE_IFID:
		if (datalen != 8) goto raw;
		break;

	case PW_TYPE_IPV6_ADDR:
		if (datalen != 16) goto raw;
		break;

	case PW_TYPE_IPV6_PREFIX:
		if ((datalen < 2) || (datalen > 18)) goto raw;
		if (data[1] > 128) goto raw;
		break;

	case PW_TYPE_BYTE:
		if (datalen != 1) goto raw;
		break;

	case PW_TYPE_SHORT:
		if (datalen != 2) goto raw;
		break;

	case PW_TYPE_ETHERNET:
		if (datalen != 6) goto raw;
		break;

	case PW_TYPE_COMBO_IP_ADDR:
		if (datalen == 4) {
			child = dict_attrbytype(da->attr, da->vendor,
						PW_TYPE_IPV4_ADDR);
		} else if (datalen == 16) {
			child = dict_attrbytype(da->attr, da->vendor,
					     PW_TYPE_IPV6_ADDR);
		} else {
			goto raw;
		}
		if (!child) goto raw;
		da = child;	/* re-write it */
		break;

	case PW_TYPE_IPV4_PREFIX:
		if (datalen != 6) goto raw;
		if ((data[1] & 0x3f) > 32) goto raw;
		break;

		/*
		 *	The rest of the data types can cause
		 *	recursion!  Ask yourself, "is recursion OK?"
		 */

	case PW_TYPE_EXTENDED:
		if (datalen < 2) goto raw; /* etype, value */

		child = dict_attrbyparent(da, data[0], 0);
		if (!child) goto raw;

		/*
		 *	Recurse to decode the contents, which could be
		 *	a TLV, IPaddr, etc.  Note that we decode only
		 *	the current attribute, and we ignore any extra
		 *	data after it.
		 */
		rcode = data2vp(ctx, packet, original, secret, child,
				data + 1, attrlen - 1, attrlen - 1, pvp);
		if (rcode < 0) goto raw;
		return 1 + rcode;

	case PW_TYPE_LONG_EXTENDED:
		if (datalen < 3) goto raw; /* etype, flags, value */

		child = dict_attrbyparent(da, data[0], 0);
		if (!child) {
			if ((data[0] != PW_VENDOR_SPECIFIC) ||
			    (datalen < (3 + 4 + 1))) {
				/* da->attr < 255, da->vendor == 0 */
				child = dict_unknown_afrom_fields(ctx, data[0], da->attr * FR_MAX_VENDOR);
			} else {
				/*
				 *	Try to find the VSA.
				 */
				memcpy(&vendor, data + 3, 4);
				vendor = ntohl(vendor);

				if (vendor == 0) goto raw;

				child = dict_unknown_afrom_fields(ctx, data[7], vendor | (da->attr * FR_MAX_VENDOR));
			}

			if (!child) {
				fr_strerror_printf("Internal sanity check %d", __LINE__);
				return -1;
			}
		}

		/*
		 *	If there no more fragments, then the contents
		 *	have to be a well-known data type.
		 *
		 */
		if ((data[1] & 0x80) == 0) {
			rcode = data2vp(ctx, packet, original, secret, child,
					data + 2, attrlen - 2, attrlen - 2,
					pvp);
			if (rcode < 0) goto raw;
			return 2 + rcode;
		}

		/*
		 *	This requires a whole lot more work.
		 */
		return data2vp_extended(ctx, packet, original, secret, child,
					start, attrlen, packetlen, pvp);

	case PW_TYPE_EVS:
		if (datalen < 6) goto raw; /* vid, vtype, value */

		if (data[0] != 0) goto raw; /* we require 24-bit VIDs */

		memcpy(&vendor, data, 4);
		vendor = ntohl(vendor);
		vendor |= da->vendor;

		child = dict_attrbyvalue(data[4], vendor);
		if (!child) {
			/*
			 *	Create a "raw" attribute from the
			 *	contents of the EVS VSA.
			 */
			da = dict_unknown_afrom_fields(ctx, data[4], vendor);
			data += 5;
			datalen -= 5;
			break;
		}

		rcode = data2vp(ctx, packet, original, secret, child,
				data + 5, attrlen - 5, attrlen - 5, pvp);
		if (rcode < 0) goto raw;
		return 5 + rcode;

	case PW_TYPE_TLV:
		/*
		 *	We presume that the TLVs all fit into one
		 *	attribute, OR they've already been grouped
		 *	into a contiguous memory buffer.
		 */
		rcode = data2vp_tlvs(ctx, packet, original, secret, da,
				     data, attrlen, pvp);
		if (rcode < 0) goto raw;
		return rcode;

	case PW_TYPE_VSA:
		/*
		 *	VSAs can be WiMAX, in which case they don't
		 *	fit into one attribute.
		 */
		rcode = data2vp_vsas(ctx, packet, original, secret,
				     data, attrlen, packetlen, pvp);
		if (rcode < 0) goto raw;
		return rcode;

	default:
	raw:
		/*
		 *	Re-write the attribute to be "raw".  It is
		 *	therefore of type "octets", and will be
		 *	handled below.
		 */
		da = dict_unknown_afrom_fields(ctx, da->attr, da->vendor);
		if (!da) {
			fr_strerror_printf("Internal sanity check %d", __LINE__);
			return -1;
		}
		tag = TAG_NONE;
#ifndef NDEBUG
		/*
		 *	Fix for Coverity.
		 */
		if (da->type != PW_TYPE_OCTETS) {
			dict_attr_free(&da);
			return -1;
		}
#endif
		break;
	}

	/*
	 *	And now that we've verified the basic type
	 *	information, decode the actual data.
	 */
 alloc_cui:
	vp = pairalloc(ctx, da);
	if (!vp) return -1;

	vp->vp_length = datalen;
	vp->tag = tag;

	switch (da->type) {
	case PW_TYPE_STRING:
		p = talloc_array(vp, char, vp->vp_length + 1);
		memcpy(p, data, vp->vp_length);
		p[vp->vp_length] = '\0';
		vp->vp_strvalue = p;
		break;

	case PW_TYPE_OCTETS:
		pairmemcpy(vp, data, vp->vp_length);
		break;

	case PW_TYPE_ABINARY:
		if (vp->vp_length > sizeof(vp->vp_filter)) {
			vp->vp_length = sizeof(vp->vp_filter);
		}
		memcpy(vp->vp_filter, data, vp->vp_length);
		break;

	case PW_TYPE_BYTE:
		vp->vp_byte = data[0];
		break;

	case PW_TYPE_SHORT:
		vp->vp_short = (data[0] << 8) | data[1];
		break;

	case PW_TYPE_INTEGER:
		memcpy(&vp->vp_integer, data, 4);
		vp->vp_integer = ntohl(vp->vp_integer);
		break;

	case PW_TYPE_INTEGER64:
		memcpy(&vp->vp_integer64, data, 8);
		vp->vp_integer64 = ntohll(vp->vp_integer64);
		break;

	case PW_TYPE_DATE:
		memcpy(&vp->vp_date, data, 4);
		vp->vp_date = ntohl(vp->vp_date);
		break;

	case PW_TYPE_ETHERNET:
		memcpy(vp->vp_ether, data, 6);
		break;

	case PW_TYPE_IPV4_ADDR:
		memcpy(&vp->vp_ipaddr, data, 4);
		break;

	case PW_TYPE_IFID:
		memcpy(vp->vp_ifid, data, 8);
		break;

	case PW_TYPE_IPV6_ADDR:
		memcpy(&vp->vp_ipv6addr, data, 16);
		break;

	case PW_TYPE_IPV6_PREFIX:
		/*
		 *	FIXME: double-check that
		 *	(vp->vp_octets[1] >> 3) matches vp->vp_length + 2
		 */
		memcpy(vp->vp_ipv6prefix, data, vp->vp_length);
		if (vp->vp_length < 18) {
			memset(((uint8_t *)vp->vp_ipv6prefix) + vp->vp_length, 0,
			       18 - vp->vp_length);
		}
		break;

	case PW_TYPE_IPV4_PREFIX:
		/* FIXME: do the same double-check as for IPv6Prefix */
		memcpy(vp->vp_ipv4prefix, data, vp->vp_length);

		/*
		 *	/32 means "keep all bits".  Otherwise, mask
		 *	them out.
		 */
		if ((data[1] & 0x3f) > 32) {
			uint32_t addr, mask;

			memcpy(&addr, vp->vp_octets + 2, sizeof(addr));
			mask = 1;
			mask <<= (32 - (data[1] & 0x3f));
			mask--;
			mask = ~mask;
			mask = htonl(mask);
			addr &= mask;
			memcpy(vp->vp_ipv4prefix + 2, &addr, sizeof(addr));
		}
		break;

	case PW_TYPE_SIGNED:	/* overloaded with vp_integer */
		memcpy(&vp->vp_integer, buffer, 4);
		vp->vp_integer = ntohl(vp->vp_integer);
		break;

	default:
		pairfree(&vp);
		fr_strerror_printf("Internal sanity check %d", __LINE__);
		return -1;
	}
	vp->type = VT_DATA;
	*pvp = vp;

	return attrlen;
}


/** Create a "normal" VALUE_PAIR from the given data
 *
 */
ssize_t rad_attr2vp(TALLOC_CTX *ctx,
		    RADIUS_PACKET *packet, RADIUS_PACKET const *original,
		    char const *secret,
		    uint8_t const *data, size_t length,
		    VALUE_PAIR **pvp)
{
	ssize_t rcode;

	DICT_ATTR const *da;

	if ((length < 2) || (data[1] < 2) || (data[1] > length)) {
		fr_strerror_printf("rad_attr2vp: Insufficient data");
		return -1;
	}

	da = dict_attrbyvalue(data[0], 0);
	if (!da) {
		VP_TRACE("attr2vp: unknown attribute %u\n", data[0]);
		da = dict_unknown_afrom_fields(ctx, data[0], 0);
	}
	if (!da) return -1;

	/*
	 *	Pass the entire thing to the decoding function
	 */
	if (da->flags.concat) {
		VP_TRACE("attr2vp: concat attribute\n");
		return data2vp_concat(ctx, da, data, length, pvp);
	}

	/*
	 *	Note that we pass the entire length, not just the
	 *	length of this attribute.  The Extended or WiMAX
	 *	attributes may have the "continuation" bit set, and
	 *	will thus be more than one attribute in length.
	 */
	rcode = data2vp(ctx, packet, original, secret, da,
			data + 2, data[1] - 2, length - 2, pvp);
	if (rcode < 0) return rcode;

	return 2 + rcode;
}

fr_thread_local_setup(uint8_t *, rad_vp2data_buff)

/** Converts vp_data to network byte order
 *
 * Provide a pointer to a buffer which contains the value of the VALUE_PAIR
 * in an architecture independent format.
 *
 * The pointer is only guaranteed to be valid between calls to rad_vp2data, and so long
 * as the source VALUE_PAIR is not freed.
 *
 * @param out where to write the pointer to the value.
 * @param vp to get the value from.
 * @return
 *	- The length of the value.
 *	- -1 on failure.
 */
ssize_t rad_vp2data(uint8_t const **out, VALUE_PAIR const *vp)
{
	uint8_t		*buffer;
	uint32_t	lvalue;
	uint64_t	lvalue64;

	*out = NULL;

	buffer = fr_thread_local_init(rad_vp2data_buff, free);
	if (!buffer) {
		int ret;

		buffer = malloc(sizeof(uint8_t) * sizeof(value_data_t));
		if (!buffer) {
			fr_strerror_printf("Failed allocating memory for rad_vp2data buffer");
			return -1;
		}

		ret = fr_thread_local_set(rad_vp2data_buff, buffer);
		if (ret != 0) {
			fr_strerror_printf("Failed setting up TLS for rad_vp2data buffer: %s", strerror(errno));
			free(buffer);
			return -1;
		}
	}

	VERIFY_VP(vp);

	switch (vp->da->type) {
	case PW_TYPE_STRING:
	case PW_TYPE_OCTETS:
	case PW_TYPE_TLV:
		memcpy(out, &vp->data.ptr, sizeof(*out));
		break;

	/*
	 *	All of these values are at the same location.
	 */
	case PW_TYPE_IFID:
	case PW_TYPE_IPV4_ADDR:
	case PW_TYPE_IPV6_ADDR:
	case PW_TYPE_IPV6_PREFIX:
	case PW_TYPE_IPV4_PREFIX:
	case PW_TYPE_ABINARY:
	case PW_TYPE_ETHERNET:
	case PW_TYPE_COMBO_IP_ADDR:
	case PW_TYPE_COMBO_IP_PREFIX:
	{
		void const *p = &vp->data;
		memcpy(out, &p, sizeof(*out));
		break;
	}

	case PW_TYPE_BOOLEAN:
		buffer[0] = vp->vp_byte & 0x01;
		*out = buffer;
		break;

	case PW_TYPE_BYTE:
		buffer[0] = vp->vp_byte & 0xff;
		*out = buffer;
		break;

	case PW_TYPE_SHORT:
		buffer[0] = (vp->vp_short >> 8) & 0xff;
		buffer[1] = vp->vp_short & 0xff;
		*out = buffer;
		break;

	case PW_TYPE_INTEGER:
		lvalue = htonl(vp->vp_integer);
		memcpy(buffer, &lvalue, sizeof(lvalue));
		*out = buffer;
		break;

	case PW_TYPE_INTEGER64:
		lvalue64 = htonll(vp->vp_integer64);
		memcpy(buffer, &lvalue64, sizeof(lvalue64));
		*out = buffer;
		break;

	case PW_TYPE_DATE:
		lvalue = htonl(vp->vp_date);
		memcpy(buffer, &lvalue, sizeof(lvalue));
		*out = buffer;
		break;

	case PW_TYPE_SIGNED:
	{
		int32_t slvalue = htonl(vp->vp_signed);
		memcpy(buffer, &slvalue, sizeof(slvalue));
		*out = buffer;
		break;
	}

	case PW_TYPE_INVALID:
	case PW_TYPE_EXTENDED:
	case PW_TYPE_LONG_EXTENDED:
	case PW_TYPE_EVS:
	case PW_TYPE_VSA:
	case PW_TYPE_TIMEVAL:
	case PW_TYPE_MAX:
		fr_strerror_printf("Cannot get data for VALUE_PAIR type %i", vp->da->type);
		return -1;

	/* Don't add default */
	}

	return vp->vp_length;
}

/** Calculate/check digest, and decode radius attributes
 *
 * @return
 *	- 0 on success
 *	- -1 on decoding error.
 */
int rad_decode(RADIUS_PACKET *packet, RADIUS_PACKET *original,
	       char const *secret)
{
	int			packet_length;
	uint32_t		num_attributes;
	uint8_t			*ptr;
	radius_packet_t		*hdr;
	VALUE_PAIR *head, **tail, *vp;

	/*
	 *	Extract attribute-value pairs
	 */
	hdr = (radius_packet_t *)packet->data;
	ptr = hdr->data;
	packet_length = packet->data_len - RADIUS_HDR_LEN;

	head = NULL;
	tail = &head;
	num_attributes = 0;

	/*
	 *	Loop over the attributes, decoding them into VPs.
	 */
	while (packet_length > 0) {
		ssize_t my_len;

		/*
		 *	This may return many VPs
		 */
		my_len = rad_attr2vp(packet, packet, original, secret,
				     ptr, packet_length, &vp);
		if (my_len < 0) {
			pairfree(&head);
			return -1;
		}

		*tail = vp;
		while (vp) {
			num_attributes++;
			tail = &(vp->next);
			vp = vp->next;
		}

		/*
		 *	VSA's may not have been counted properly in
		 *	rad_packet_ok() above, as it is hard to count
		 *	then without using the dictionary.  We
		 *	therefore enforce the limits here, too.
		 */
		if ((fr_max_attributes > 0) &&
		    (num_attributes > fr_max_attributes)) {
			char host_ipaddr[128];

			pairfree(&head);
			fr_strerror_printf("Possible DoS attack from host %s: Too many attributes in request (received %d, max %d are allowed).",
				   inet_ntop(packet->src_ipaddr.af,
					     &packet->src_ipaddr.ipaddr,
					     host_ipaddr, sizeof(host_ipaddr)),
				   num_attributes, fr_max_attributes);
			return -1;
		}

		ptr += my_len;
		packet_length -= my_len;
	}

	/*
	 *	Merge information from the outside world into our
	 *	random pool.
	 */
	fr_rand_seed(packet->data, RADIUS_HDR_LEN);

	/*
	 *	There may be VP's already in the packet.  Don't
	 *	destroy them.  Instead, add the decoded attributes to
	 *	the tail of the list.
	 */
	for (tail = &packet->vps; *tail != NULL; tail = &((*tail)->next)) {
		/* nothing */
	}
	*tail = head;

	return 0;
}


/** Encode password
 *
 * We assume that the passwd buffer passed is big enough.
 * RFC2138 says the password is max 128 chars, so the size
 * of the passwd buffer must be at least 129 characters.
 * Preferably it's just MAX_STRING_LEN.
 *
 * int *pwlen is updated to the new length of the encrypted
 * password - a multiple of 16 bytes.
 */
int rad_pwencode(char *passwd, size_t *pwlen, char const *secret,
		 uint8_t const *vector)
{
	FR_MD5_CTX context, old;
	uint8_t	digest[AUTH_VECTOR_LEN];
	int	i, n, secretlen;
	int	len;

	/*
	 *	RFC maximum is 128 bytes.
	 *
	 *	If length is zero, pad it out with zeros.
	 *
	 *	If the length isn't aligned to 16 bytes,
	 *	zero out the extra data.
	 */
	len = *pwlen;

	if (len > 128) len = 128;

	if (len == 0) {
		memset(passwd, 0, AUTH_PASS_LEN);
		len = AUTH_PASS_LEN;
	} else if ((len % AUTH_PASS_LEN) != 0) {
		memset(&passwd[len], 0, AUTH_PASS_LEN - (len % AUTH_PASS_LEN));
		len += AUTH_PASS_LEN - (len % AUTH_PASS_LEN);
	}
	*pwlen = len;

	/*
	 *	Use the secret to setup the decryption digest
	 */
	secretlen = strlen(secret);

	fr_md5_init(&context);
	fr_md5_update(&context, (uint8_t const *) secret, secretlen);
	old = context;		/* save intermediate work */

	/*
	 *	Encrypt it in place.  Don't bother checking
	 *	len, as we've ensured above that it's OK.
	 */
	for (n = 0; n < len; n += AUTH_PASS_LEN) {
		if (n == 0) {
			fr_md5_update(&context, vector, AUTH_PASS_LEN);
			fr_md5_final(digest, &context);
		} else {
			context = old;
			fr_md5_update(&context,
				     (uint8_t *) passwd + n - AUTH_PASS_LEN,
				     AUTH_PASS_LEN);
			fr_md5_final(digest, &context);
		}

		for (i = 0; i < AUTH_PASS_LEN; i++) {
			passwd[i + n] ^= digest[i];
		}
	}

	return 0;
}

/** Decode password
 *
 */
int rad_pwdecode(char *passwd, size_t pwlen, char const *secret,
		 uint8_t const *vector)
{
	FR_MD5_CTX context, old;
	uint8_t	digest[AUTH_VECTOR_LEN];
	int	i;
	size_t	n, secretlen;

	/*
	 *	The RFC's say that the maximum is 128.
	 *	The buffer we're putting it into above is 254, so
	 *	we don't need to do any length checking.
	 */
	if (pwlen > 128) pwlen = 128;

	/*
	 *	Catch idiots.
	 */
	if (pwlen == 0) goto done;

	/*
	 *	Use the secret to setup the decryption digest
	 */
	secretlen = strlen(secret);

	fr_md5_init(&context);
	fr_md5_update(&context, (uint8_t const *) secret, secretlen);
	old = context;		/* save intermediate work */

	/*
	 *	The inverse of the code above.
	 */
	for (n = 0; n < pwlen; n += AUTH_PASS_LEN) {
		if (n == 0) {
			fr_md5_update(&context, vector, AUTH_VECTOR_LEN);
			fr_md5_final(digest, &context);

			context = old;
			if (pwlen > AUTH_PASS_LEN) {
				fr_md5_update(&context, (uint8_t *) passwd,
					     AUTH_PASS_LEN);
			}
		} else {
			fr_md5_final(digest, &context);

			context = old;
			if (pwlen > (n + AUTH_PASS_LEN)) {
				fr_md5_update(&context, (uint8_t *) passwd + n,
					     AUTH_PASS_LEN);
			}
		}

		for (i = 0; i < AUTH_PASS_LEN; i++) {
			passwd[i + n] ^= digest[i];
		}
	}

 done:
	passwd[pwlen] = '\0';
	return strlen(passwd);
}


/** Encode Tunnel-Password attributes when sending them out on the wire
 *
 * int *pwlen is updated to the new length of the encrypted
 * password - a multiple of 16 bytes.
 *
 * This is per RFC-2868 which adds a two char SALT to the initial intermediate
 * value MD5 hash.
 */
int rad_tunnel_pwencode(char *passwd, size_t *pwlen, char const *secret,
			uint8_t const *vector)
{
	uint8_t	buffer[AUTH_VECTOR_LEN + MAX_STRING_LEN + 3];
	unsigned char	digest[AUTH_VECTOR_LEN];
	char*   salt;
	int	i, n, secretlen;
	unsigned len, n2;

	len = *pwlen;

	if (len > 127) len = 127;

	/*
	 * Shift the password 3 positions right to place a salt and original
	 * length, tag will be added automatically on packet send
	 */
	for (n=len ; n>=0 ; n--) passwd[n+3] = passwd[n];
	salt = passwd;
	passwd += 2;
	/*
	 * save original password length as first password character;
	 */
	*passwd = len;
	len += 1;


	/*
	 *	Generate salt.  The RFC's say:
	 *
	 *	The high bit of salt[0] must be set, each salt in a
	 *	packet should be unique, and they should be random
	 *
	 *	So, we set the high bit, add in a counter, and then
	 *	add in some CSPRNG data.  should be OK..
	 */
	salt[0] = (0x80 | ( ((salt_offset++) & 0x0f) << 3) |
		   (fr_rand() & 0x07));
	salt[1] = fr_rand();

	/*
	 *	Padd password to multiple of AUTH_PASS_LEN bytes.
	 */
	n = len % AUTH_PASS_LEN;
	if (n) {
		n = AUTH_PASS_LEN - n;
		for (; n > 0; n--, len++)
			passwd[len] = 0;
	}
	/* set new password length */
	*pwlen = len + 2;

	/*
	 *	Use the secret to setup the decryption digest
	 */
	secretlen = strlen(secret);
	memcpy(buffer, secret, secretlen);

	for (n2 = 0; n2 < len; n2+=AUTH_PASS_LEN) {
		if (!n2) {
			memcpy(buffer + secretlen, vector, AUTH_VECTOR_LEN);
			memcpy(buffer + secretlen + AUTH_VECTOR_LEN, salt, 2);
			fr_md5_calc(digest, buffer, secretlen + AUTH_VECTOR_LEN + 2);
		} else {
			memcpy(buffer + secretlen, passwd + n2 - AUTH_PASS_LEN, AUTH_PASS_LEN);
			fr_md5_calc(digest, buffer, secretlen + AUTH_PASS_LEN);
		}

		for (i = 0; i < AUTH_PASS_LEN; i++) {
			passwd[i + n2] ^= digest[i];
		}
	}
	passwd[n2] = 0;
	return 0;
}

/** Decode Tunnel-Password encrypted attributes
 *
 * Defined in RFC-2868, this uses a two char SALT along with the
 * initial intermediate value, to differentiate it from the
 * above.
 */
int rad_tunnel_pwdecode(uint8_t *passwd, size_t *pwlen, char const *secret,
			uint8_t const *vector)
{
	FR_MD5_CTX  context, old;
	uint8_t		digest[AUTH_VECTOR_LEN];
	int		secretlen;
	unsigned	i, n, len, reallen;

	len = *pwlen;

	/*
	 *	We need at least a salt.
	 */
	if (len < 2) {
		fr_strerror_printf("tunnel password is too short");
		return -1;
	}

	/*
	 *	There's a salt, but no password.  Or, there's a salt
	 *	and a 'data_len' octet.  It's wrong, but at least we
	 *	can figure out what it means: the password is empty.
	 *
	 *	Note that this means we ignore the 'data_len' field,
	 *	if the attribute length tells us that there's no
	 *	more data.  So the 'data_len' field may be wrong,
	 *	but that's ok...
	 */
	if (len <= 3) {
		passwd[0] = 0;
		*pwlen = 0;
		return 0;
	}

	len -= 2;		/* discount the salt */

	/*
	 *	Use the secret to setup the decryption digest
	 */
	secretlen = strlen(secret);

	fr_md5_init(&context);
	fr_md5_update(&context, (uint8_t const *) secret, secretlen);
	old = context;		/* save intermediate work */

	/*
	 *	Set up the initial key:
	 *
	 *	 b(1) = MD5(secret + vector + salt)
	 */
	fr_md5_update(&context, vector, AUTH_VECTOR_LEN);
	fr_md5_update(&context, passwd, 2);

	reallen = 0;
	for (n = 0; n < len; n += AUTH_PASS_LEN) {
		int base = 0;

		if (n == 0) {
			fr_md5_final(digest, &context);

			context = old;

			/*
			 *	A quick check: decrypt the first octet
			 *	of the password, which is the
			 *	'data_len' field.  Ensure it's sane.
			 */
			reallen = passwd[2] ^ digest[0];
			if (reallen >= len) {
				fr_strerror_printf("tunnel password is too long for the attribute");
				return -1;
			}

			fr_md5_update(&context, passwd + 2, AUTH_PASS_LEN);

			base = 1;
		} else {
			fr_md5_final(digest, &context);

			context = old;
			fr_md5_update(&context, passwd + n + 2, AUTH_PASS_LEN);
		}

		for (i = base; i < AUTH_PASS_LEN; i++) {
			passwd[n + i - 1] = passwd[n + i + 2] ^ digest[i];
		}
	}

	/*
	 *	See make_tunnel_password, above.
	 */
	if (reallen > 239) reallen = 239;

	*pwlen = reallen;
	passwd[reallen] = 0;

	return reallen;
}

/** Encode a CHAP password
 *
 * @bug FIXME: might not work with Ascend because
 * we use vp->vp_length, and Ascend gear likes
 * to send an extra '\0' in the string!
 */
int rad_chap_encode(RADIUS_PACKET *packet, uint8_t *output, int id,
		    VALUE_PAIR *password)
{
	int		i;
	uint8_t		*ptr;
	uint8_t		string[MAX_STRING_LEN * 2 + 1];
	VALUE_PAIR	*challenge;

	/*
	 *	Sanity check the input parameters
	 */
	if ((packet == NULL) || (password == NULL)) {
		return -1;
	}

	/*
	 *	Note that the password VP can be EITHER
	 *	a User-Password attribute (from a check-item list),
	 *	or a CHAP-Password attribute (the client asking
	 *	the library to encode it).
	 */

	i = 0;
	ptr = string;
	*ptr++ = id;

	i++;
	memcpy(ptr, password->vp_strvalue, password->vp_length);
	ptr += password->vp_length;
	i += password->vp_length;

	/*
	 *	Use Chap-Challenge pair if present,
	 *	Request Authenticator otherwise.
	 */
	challenge = pairfind(packet->vps, PW_CHAP_CHALLENGE, 0, TAG_ANY);
	if (challenge) {
		memcpy(ptr, challenge->vp_strvalue, challenge->vp_length);
		i += challenge->vp_length;
	} else {
		memcpy(ptr, packet->vector, AUTH_VECTOR_LEN);
		i += AUTH_VECTOR_LEN;
	}

	*output = id;
	fr_md5_calc((uint8_t *)output + 1, (uint8_t *)string, i);

	return 0;
}


/** Seed the random number generator
 *
 * May be called any number of times.
 */
void fr_rand_seed(void const *data, size_t size)
{
	uint32_t hash;

	/*
	 *	Ensure that the pool is initialized.
	 */
	if (!fr_rand_initialized) {
		int fd;

		memset(&fr_rand_pool, 0, sizeof(fr_rand_pool));

		fd = open("/dev/urandom", O_RDONLY);
		if (fd >= 0) {
			size_t total;
			ssize_t this;

			total = 0;
			while (total < sizeof(fr_rand_pool.randrsl)) {
				this = read(fd, fr_rand_pool.randrsl,
					    sizeof(fr_rand_pool.randrsl) - total);
				if ((this < 0) && (errno != EINTR)) break;
				if (this > 0) total += this;
			}
			close(fd);
		} else {
			fr_rand_pool.randrsl[0] = fd;
			fr_rand_pool.randrsl[1] = time(NULL);
			fr_rand_pool.randrsl[2] = errno;
		}

		fr_randinit(&fr_rand_pool, 1);
		fr_rand_pool.randcnt = 0;
		fr_rand_initialized = 1;
	}

	if (!data) return;

	/*
	 *	Hash the user data
	 */
	hash = fr_rand();
	if (!hash) hash = fr_rand();
	hash = fr_hash_update(data, size, hash);

	fr_rand_pool.randmem[fr_rand_pool.randcnt] ^= hash;
}


/** Return a 32-bit random number
 *
 */
uint32_t fr_rand(void)
{
	uint32_t num;

	/*
	 *	Ensure that the pool is initialized.
	 */
	if (!fr_rand_initialized) {
		fr_rand_seed(NULL, 0);
	}

	num = fr_rand_pool.randrsl[fr_rand_pool.randcnt++];
	if (fr_rand_pool.randcnt >= 256) {
		fr_rand_pool.randcnt = 0;
		fr_isaac(&fr_rand_pool);
	}

	return num;
}


/** Allocate a new RADIUS_PACKET
 *
 * @param ctx the context in which the packet is allocated. May be NULL if
 *	the packet is not associated with a REQUEST.
 * @param new_vector if true a new request authenticator will be generated.
 * @return
 *	- New RADIUS_PACKET.
 *	- NULL on error.
 */
RADIUS_PACKET *rad_alloc(TALLOC_CTX *ctx, bool new_vector)
{
	RADIUS_PACKET	*rp;

	rp = talloc_zero(ctx, RADIUS_PACKET);
	if (!rp) {
		fr_strerror_printf("out of memory");
		return NULL;
	}
	rp->id = -1;
	rp->offset = -1;

	if (new_vector) {
		int i;
		uint32_t hash, base;

		/*
		 *	Don't expose the actual contents of the random
		 *	pool.
		 */
		base = fr_rand();
		for (i = 0; i < AUTH_VECTOR_LEN; i += sizeof(uint32_t)) {
			hash = fr_rand() ^ base;
			memcpy(rp->vector + i, &hash, sizeof(hash));
		}
	}
	fr_rand();		/* stir the pool again */

	return rp;
}

/** Allocate a new RADIUS_PACKET response
 *
 * @param ctx the context in which the packet is allocated. May be NULL if
 *	the packet is not associated with a REQUEST.
 * @param packet The request packet.
 * @return
 *	- New RADIUS_PACKET.
 *	- NULL on error.
 */
RADIUS_PACKET *rad_alloc_reply(TALLOC_CTX *ctx, RADIUS_PACKET *packet)
{
	RADIUS_PACKET *reply;

	if (!packet) return NULL;

	reply = rad_alloc(ctx, false);
	if (!reply) return NULL;

	/*
	 *	Initialize the fields from the request.
	 */
	reply->sockfd = packet->sockfd;
	reply->dst_ipaddr = packet->src_ipaddr;
	reply->src_ipaddr = packet->dst_ipaddr;
	reply->dst_port = packet->src_port;
	reply->src_port = packet->dst_port;
	reply->id = packet->id;
	reply->code = 0; /* UNKNOWN code */
	memcpy(reply->vector, packet->vector,
	       sizeof(reply->vector));
	reply->vps = NULL;
	reply->data = NULL;
	reply->data_len = 0;

#ifdef WITH_TCP
	reply->proto = packet->proto;
#endif
	return reply;
}


/** Free a RADIUS_PACKET
 *
 */
void rad_free(RADIUS_PACKET **radius_packet_ptr)
{
	RADIUS_PACKET *radius_packet;

	if (!radius_packet_ptr || !*radius_packet_ptr) return;
	radius_packet = *radius_packet_ptr;

	VERIFY_PACKET(radius_packet);

	pairfree(&radius_packet->vps);

	talloc_free(radius_packet);
	*radius_packet_ptr = NULL;
}

/** Duplicate a RADIUS_PACKET
 *
 * @param ctx the context in which the packet is allocated. May be NULL if
 *	the packet is not associated with a REQUEST.
 * @param in The packet to copy
 * @return
 *	- New RADIUS_PACKET.
 *	- NULL on error.
 */
RADIUS_PACKET *rad_copy_packet(TALLOC_CTX *ctx, RADIUS_PACKET const *in)
{
	RADIUS_PACKET *out;

	out = rad_alloc(ctx, false);
	if (!out) return NULL;

	/*
	 *	Bootstrap by copying everything.
	 */
	memcpy(out, in, sizeof(*out));

	/*
	 *	Then reset necessary fields
	 */
	out->sockfd = -1;

	out->data = NULL;
	out->data_len = 0;

	out->vps = paircopy(out, in->vps);
	out->offset = 0;

	return out;
}