Merge branch 'libradsec-new-client' into libradsec

1 files changed, 916 insertions, 0 deletions

diff --git a/lib/radius/radpkt.c b/lib/radius/radpkt.c
new file mode 100644
index 0000000..bb8f75e
--- /dev/null
+++ b/lib/radius/radpkt.c
@@ -0,0 +1,916 @@
+/*
+Copyright (c) 2011, Network RADIUS SARL
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+    * Neither the name of the <organization> nor the
+      names of its contributors may be used to endorse or promote products
+      derived from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
+DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/** \file packet.c
+ *  \brief Encoding and decoding packets
+ */
+
+#include	"client.h"
+
+#if RS_MAX_PACKET_LEN < 64
+#error RS_MAX_PACKET_LEN is too small.  It should be at least 64.
+#endif
+
+#if RS_MAX_PACKET_LEN > 16384
+#error RS_MAX_PACKET_LEN is too large.  It should be smaller than 16K.
+#endif
+
+const char *nr_packet_codes[RS_MAX_PACKET_CODE + 1] = {
+  NULL,
+  "Access-Request",
+  "Access-Accept",
+  "Access-Reject",
+  "Accounting-Request",
+  "Accounting-Response",
+  NULL, NULL, NULL, NULL, NULL,
+  "Access-Challenge",
+  "Status-Server",		/* 12 */
+  NULL, NULL, NULL, NULL, NULL, NULL, NULL, /* 19 */
+  NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, /* 20..29 */
+  NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, /* 30..39 */
+  "Disconnect-Request",
+  "Disconnect-ACK",
+  "Disconnect-NAK",
+  "CoA-Request",
+  "CoA-ACK",
+  "CoA-NAK"
+};
+
+
+static uint64_t allowed_responses[RS_MAX_PACKET_CODE + 1] = {
+	0,
+	(1 << PW_ACCESS_ACCEPT) | (1 << PW_ACCESS_REJECT) | (1 << PW_ACCESS_CHALLENGE),
+	0, 0,
+	1 << PW_ACCOUNTING_RESPONSE,
+	0,
+	0, 0, 0, 0, 0,
+	0,
+	(1 << PW_ACCESS_ACCEPT) | (1 << PW_ACCESS_REJECT) | (1 << PW_ACCESS_CHALLENGE) | (1 << PW_ACCOUNTING_RESPONSE),
+	0, 0, 0, 0, 0, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 20..29 */
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 30..39 */
+	(((uint64_t) 1) << PW_DISCONNECT_ACK) | (((uint64_t) 1) << PW_DISCONNECT_NAK),
+	0,
+	0,
+	(((uint64_t) 1) << PW_COA_ACK) | (((uint64_t) 1) << PW_COA_NAK),
+	0,
+	0
+};
+
+
+int nr_packet_ok_raw(const uint8_t *data, size_t sizeof_data)
+{
+	size_t packet_len;
+	const uint8_t *attr, *end;
+
+	if (!data || (sizeof_data < 20)) {
+		nr_debug_error("Invalid argument");
+		return -RSE_INVAL;
+	}
+
+	packet_len = (data[2] << 8) | data[3];
+	if (packet_len < 20) {
+		nr_debug_error("Packet length is too small");
+		return -RSE_PACKET_TOO_SMALL;
+	}
+
+	if (packet_len > sizeof_data) {
+		nr_debug_error("Packet length overflows received data");
+		return -RSE_PACKET_TOO_LARGE;
+	}
+
+	/*
+	 *	If we receive 100 bytes, and the header says it's 20 bytes,
+	 *	then it's 20 bytes.
+	 */
+	end = data + packet_len;
+
+	for (attr = data + 20; attr < end; attr += attr[1]) {
+		if ((attr + 2) > end) {
+			nr_debug_error("Attribute overflows packet");
+			return -RSE_ATTR_OVERFLOW;
+		}
+
+		if (attr[1] < 2) {
+			nr_debug_error("Attribute length is too small");
+			return -RSE_ATTR_TOO_SMALL;
+		}
+
+		if ((attr + attr[1]) > end) {
+			nr_debug_error("Attribute length is too large");
+			return -RSE_ATTR_TOO_LARGE;
+		}
+	}
+
+	return 0;
+}
+
+int nr_packet_ok(RADIUS_PACKET *packet)
+{
+	int rcode;
+
+	if (!packet) return -RSE_INVAL;
+
+	if ((packet->flags & RS_PACKET_OK) != 0) return 0;
+
+	rcode = nr_packet_ok_raw(packet->data, packet->length);
+	if (rcode < 0) return rcode;
+
+	packet->flags |= RS_PACKET_OK;
+	return 0;
+}
+
+
+/*
+ *	Comparison function that is time-independent.  Using "memcmp"
+ *	would satisfy the "comparison" part.  However, it would also
+ *	leak information about *which* bytes are wrong.  Attackers
+ *	could use that leak to create a "correct" RADIUS packet which
+ *	will be accepted by the client and/or server.
+ */
+static int digest_cmp(const uint8_t *a, const uint8_t *b, size_t length)
+{
+	int result = 0;
+	size_t i;
+
+	for (i = 0; i < length; i++) {
+		result |= (a[i] ^ b[i]);
+	}
+
+	return result;
+}
+
+
+#ifdef PW_MESSAGE_AUTHENTICATOR
+static int msg_auth_ok(const RADIUS_PACKET *original,
+		       uint8_t *ma,
+		       uint8_t *data, size_t length)
+{
+	uint8_t	packet_vector[sizeof(original->vector)];
+	uint8_t	msg_auth_vector[sizeof(original->vector)];
+	uint8_t calc_auth_vector[sizeof(original->vector)];
+	
+	if (ma[1] != 18) {
+		nr_debug_error("Message-Authenticator has invalid length");
+		return -RSE_MSG_AUTH_LEN;
+	}
+
+	memcpy(packet_vector, data + 4, sizeof(packet_vector));
+	memcpy(msg_auth_vector, ma + 2, sizeof(msg_auth_vector));
+	memset(ma + 2, 0, sizeof(msg_auth_vector));
+
+	switch (data[0]) {
+	default:
+		break;
+		
+	case PW_ACCOUNTING_REQUEST:
+	case PW_ACCOUNTING_RESPONSE:
+	case PW_DISCONNECT_REQUEST:
+	case PW_DISCONNECT_ACK:
+	case PW_DISCONNECT_NAK:
+	case PW_COA_REQUEST:
+	case PW_COA_ACK:
+	case PW_COA_NAK:
+		memset(data + 4, 0, sizeof(packet_vector));
+		break;
+		
+	case PW_ACCESS_ACCEPT:
+	case PW_ACCESS_REJECT:
+	case PW_ACCESS_CHALLENGE:
+		if (!original) {
+			nr_debug_error("Cannot validate response without request");
+			return -RSE_REQUEST_REQUIRED;
+		}
+		memcpy(data + 4, original->vector, sizeof(original->vector));
+		break;
+	}
+	
+	nr_hmac_md5(data, length,
+		    (const uint8_t *) original->secret, original->sizeof_secret,
+		    calc_auth_vector);
+
+	memcpy(ma + 2, msg_auth_vector, sizeof(msg_auth_vector));
+	memcpy(data + 4, packet_vector, sizeof(packet_vector));
+
+	if (digest_cmp(calc_auth_vector, msg_auth_vector,
+		       sizeof(calc_auth_vector)) != 0) {
+		nr_debug_error("Invalid Message-Authenticator");
+		return -RSE_MSG_AUTH_WRONG;
+	}
+
+	return 1;
+}
+#endif
+
+/*
+ *	The caller ensures that the packet codes are as expected.
+ */
+static int packet_auth_ok(const RADIUS_PACKET *original,
+			  uint8_t *data, size_t length)
+{
+	uint8_t packet_vector[sizeof(original->vector)];
+	uint8_t calc_digest[sizeof(original->vector)];
+	RS_MD5_CTX ctx;
+
+	if ((data[0] == PW_ACCESS_REQUEST) ||
+	    (data[0] == PW_STATUS_SERVER)) return 1;
+
+	memcpy(packet_vector, data + 4, sizeof(packet_vector));
+
+	if (!original) {
+		memset(data + 4, 0, sizeof(packet_vector));
+	} else {
+		memcpy(data + 4, original->vector, sizeof(original->vector));
+	}
+
+	RS_MD5Init(&ctx);
+	RS_MD5Update(&ctx, data, length);
+	RS_MD5Update(&ctx, (const unsigned char *)original->secret, original->sizeof_secret);
+	RS_MD5Final(calc_digest, &ctx);
+
+	memcpy(data + 4, packet_vector, sizeof(packet_vector));
+
+	if (digest_cmp(calc_digest, packet_vector,
+		       sizeof(packet_vector)) != 0) {
+		nr_debug_error("Invalid authentication vector");
+		return -RSE_AUTH_VECTOR_WRONG;
+	}
+
+	return 0;
+}
+
+
+int nr_packet_verify(RADIUS_PACKET *packet, const RADIUS_PACKET *original)
+{
+	int rcode;
+	uint8_t *attr;
+#ifdef PW_MESSAGE_AUTHENTICATOR
+	const uint8_t *end;
+#endif
+
+	if (!packet || !packet->data || !packet->secret) {
+		nr_debug_error("Invalid argument");
+		return -RSE_INVAL;
+	}
+
+	if ((packet->flags & RS_PACKET_VERIFIED) != 0) return 0;
+
+	/*
+	 *	Packet isn't well formed.  Ignore it.
+	 */
+	rcode = nr_packet_ok(packet);
+	if (rcode < 0) return rcode;
+
+	/*
+	 *	Get rid of improper packets as early as possible.
+	 */
+	if (original) {
+		uint64_t mask;
+
+		if (original->code > RS_MAX_PACKET_CODE) {
+			nr_debug_error("Invalid original code %u",
+					   original->code);
+			return -RSE_INVALID_REQUEST_CODE;
+		}
+
+		if (packet->data[1] != original->id) {
+			nr_debug_error("Ignoring response with wrong ID %u",
+					   packet->data[1]);
+			return -RSE_INVALID_RESPONSE_CODE;
+		}
+
+		mask = 1;
+		mask <<= packet->data[0];
+
+		if ((allowed_responses[original->code] & mask) == 0) {
+			nr_debug_error("Ignoring response with wrong code %u",
+					   packet->data[0]);
+			return -RSE_INVALID_RESPONSE_CODE;
+		}
+
+		if ((memcmp(&packet->src, &original->dst, sizeof(packet->src)) != 0) &&
+		    (evutil_sockaddr_cmp((struct sockaddr *)&packet->src, (struct sockaddr *)&original->dst, 1) != 0)) {
+			nr_debug_error("Ignoring response from wrong IP/port");
+			return -RSE_INVALID_RESPONSE_SRC;
+		}
+
+	} else if (allowed_responses[packet->data[0]] != 0) {
+		nr_debug_error("Ignoring response without original");
+		return -RSE_INVALID_RESPONSE_CODE;
+	}
+
+#ifdef PW_MESSAGE_AUTHENTICATOR
+	end = packet->data + packet->length;
+
+	/*
+	 *	Note that the packet MUST be well-formed here.
+	 */
+	for (attr = packet->data + 20; attr < end; attr += attr[1]) {
+		if (attr[0] == PW_MESSAGE_AUTHENTICATOR) {
+			rcode = msg_auth_ok(original, attr,
+					    packet->data, packet->length);
+			if (rcode < 0) return rcode;
+		}
+	}
+#endif
+
+	/*
+	 *	Verify the packet authenticator.
+	 */
+	rcode = packet_auth_ok(original, packet->data, packet->length);
+	if (rcode < 0) return rcode;
+
+	packet->flags |= RS_PACKET_VERIFIED;
+
+	return 0;
+}
+
+
+int nr_packet_decode(RADIUS_PACKET *packet, const RADIUS_PACKET *original)
+{
+	int		rcode, num_attributes;
+	uint8_t		*data, *attr;
+	const uint8_t	*end;
+	VALUE_PAIR	**tail, *vp;
+
+	if (!packet) return -RSE_INVAL;
+
+	if ((packet->flags & RS_PACKET_DECODED) != 0) return 0;
+      
+	rcode = nr_packet_ok(packet);
+	if (rcode < 0) return rcode;
+
+	data = packet->data;
+	end = data + packet->length;
+	tail = &packet->vps;
+	num_attributes = 0;
+
+	/*
+	 *	Loop over the packet, converting attrs to VPs.
+	 */
+	for (attr = data + 20; attr < end; attr += attr[1]) {
+		rcode = nr_attr2vp(packet, original,
+				    attr, end - attr, &vp);
+		if (rcode < 0) {
+			nr_vp_free(&packet->vps);
+			return -rcode;
+		}
+
+		*tail = vp;
+		while (vp) {
+			num_attributes++;
+			tail = &(vp->next);
+			vp = vp->next;
+		}
+
+		if (num_attributes > RS_MAX_ATTRIBUTES) {
+			nr_debug_error("Too many attributes");
+			nr_vp_free(&packet->vps);
+			return -RSE_TOO_MANY_ATTRS;
+		}
+	}
+
+	packet->code = data[0];
+	packet->id = data[1];
+	memcpy(packet->vector, data + 4, sizeof(packet->vector));
+
+	packet->flags |= RS_PACKET_DECODED;
+
+	return 0;
+}
+
+
+int nr_packet_sign(RADIUS_PACKET *packet, const RADIUS_PACKET *original)
+{
+#ifdef PW_MESSAGE_AUTHENTICATOR
+	size_t ma = 0;
+	const uint8_t *attr, *end;
+#endif
+
+	if ((packet->flags & RS_PACKET_SIGNED) != 0) return 0;
+
+	if ((packet->flags & RS_PACKET_ENCODED) == 0) {
+		int rcode;
+
+		rcode = nr_packet_encode(packet, original);
+		if (rcode < 0) return rcode;
+	}
+
+	if ((packet->code == PW_ACCESS_ACCEPT) ||
+	    (packet->code == PW_ACCESS_CHALLENGE) ||
+	    (packet->code == PW_ACCESS_REJECT)) {
+#ifdef PW_MESSAGE_AUTHENTICATOR
+		if (!original) {
+			nr_debug_error("Original packet is required to create the  Message-Authenticator");
+			return -RSE_REQUEST_REQUIRED;
+		}
+#endif
+		
+		memcpy(packet->data + 4, original->vector,
+		       sizeof(original->vector));
+	} else {
+		memcpy(packet->data + 4, packet->vector,
+		       sizeof(packet->vector));
+	}
+
+#ifdef PW_MESSAGE_AUTHENTICATOR
+	end = packet->data + packet->length;
+
+	for (attr = packet->data + 20; attr < end; attr += attr[1]) {
+		if (attr[0] == PW_MESSAGE_AUTHENTICATOR) {
+			ma = (attr - packet->data);
+			break;
+		}
+	}
+
+	/*
+	 *	Force all Access-Request packets to have a
+	 *	Message-Authenticator.
+	 */
+	if (!ma && ((packet->length + 18) <= packet->sizeof_data) &&
+	    ((packet->code == PW_ACCESS_REQUEST) ||
+	     (packet->code == PW_STATUS_SERVER))) {
+		ma = packet->length;
+
+		packet->data[ma]= PW_MESSAGE_AUTHENTICATOR;
+		packet->data[ma + 1] = 18;
+		memset(&packet->data[ma + 2], 0, 16);
+		packet->length += 18;
+	}
+
+	/*
+	 *	Reset the length.
+	 */
+	packet->data[2] = (packet->length >> 8) & 0xff;
+	packet->data[3] = packet->length & 0xff;
+
+	/*
+	 *	Sign the Message-Authenticator && packet.
+	 */
+	if (ma) {
+		nr_hmac_md5(packet->data, packet->length,
+			    (const uint8_t *) packet->secret, packet->sizeof_secret,
+			    packet->data + ma + 2);
+	}
+#endif
+
+	/*
+	 *	Calculate the signature.
+	 */
+	if (!((packet->code == PW_ACCESS_REQUEST) ||
+	      (packet->code == PW_STATUS_SERVER))) {
+		RS_MD5_CTX	ctx;
+
+		RS_MD5Init(&ctx);
+		RS_MD5Update(&ctx, packet->data, packet->length);
+		RS_MD5Update(&ctx, (const unsigned char *)packet->secret, packet->sizeof_secret);
+		RS_MD5Final(packet->vector, &ctx);
+	}
+
+	memcpy(packet->data + 4, packet->vector, sizeof(packet->vector));
+
+	packet->attempts = 0;
+	packet->flags |= RS_PACKET_SIGNED;
+
+	return 0;
+}
+
+
+static int can_encode_packet(RADIUS_PACKET *packet,
+			     const RADIUS_PACKET *original)
+{
+	if ((packet->code == 0) ||
+	    (packet->code > RS_MAX_PACKET_CODE) ||
+	    (original && (original->code > RS_MAX_PACKET_CODE))) {
+		nr_debug_error("Cannot send unknown packet code");
+		return -RSE_INVALID_REQUEST_CODE;
+	}
+
+	if (!nr_packet_codes[packet->code]) {
+		nr_debug_error("Cannot handle packet code %u",
+				   packet->code);
+		return -RSE_INVALID_REQUEST_CODE;
+	}
+
+#ifdef NR_NO_MALLOC
+	if (!packet->data) {
+		nr_debug_error("No place to put packet");
+		return -RSE_NO_PACKET_DATA;
+	}
+#endif
+
+	if (packet->sizeof_data < 20) {
+		nr_debug_error("The buffer is too small to encode the packet");
+		return -RSE_PACKET_TOO_SMALL;
+	}
+
+	/*
+	 *	Enforce request / response correlation.
+	 */
+	if (original) {
+		uint64_t mask;
+
+		mask = 1;
+		mask <<= packet->code;
+
+		if ((allowed_responses[original->code] & mask) == 0) {
+			nr_debug_error("Cannot encode response %u to packet %u",
+					   packet->code, original->code);
+			return -RSE_INVALID_RESPONSE_CODE;
+		}
+		packet->id = original->id;
+
+	} else if (allowed_responses[packet->code] == 0) {
+		nr_debug_error("Cannot encode response %u without original",
+				   packet->code);
+		return -RSE_REQUEST_REQUIRED;
+	}
+
+	return 0;
+}
+
+static void encode_header(RADIUS_PACKET *packet)
+{
+	if ((packet->flags & RS_PACKET_HEADER) != 0) return;
+
+	memset(packet->data, 0, 20);
+	packet->data[0] = packet->code;
+	packet->data[1] = packet->id;
+	packet->data[2] = 0;
+	packet->data[3] = 20;
+	packet->length = 20;
+
+	/*
+	 *	Calculate a random authentication vector.
+	 */
+	if ((packet->code == PW_ACCESS_REQUEST) ||
+	    (packet->code == PW_STATUS_SERVER)) {
+		nr_rand_bytes(packet->vector, sizeof(packet->vector));
+	} else {
+		memset(packet->vector, 0, sizeof(packet->vector));
+	}
+
+	memcpy(packet->data + 4, packet->vector, sizeof(packet->vector));
+
+	packet->flags |= RS_PACKET_HEADER;
+}
+
+int nr_packet_encode(RADIUS_PACKET *packet, const RADIUS_PACKET *original)
+{
+#ifdef PW_MESSAGE_AUTHENTICATOR
+	size_t ma = 0;
+#endif
+	int rcode;
+	ssize_t len;
+	const VALUE_PAIR *vp;
+	uint8_t *data, *end;
+
+	if ((packet->flags & RS_PACKET_ENCODED) != 0) return 0;
+
+	rcode = can_encode_packet(packet, original);
+	if (rcode < 0) return rcode;
+
+	data = packet->data;
+	end = data + packet->sizeof_data;
+
+	encode_header(packet);
+	data += 20;
+
+	/*
+	 *	Encode each VALUE_PAIR
+	 */
+	vp = packet->vps;
+	while (vp) {
+#ifdef PW_MESSAGE_AUTHENTICATOR
+		if (vp->da->attr == PW_MESSAGE_AUTHENTICATOR) {
+			ma = (data - packet->data);
+		}
+#endif
+		len = nr_vp2attr(packet, original, &vp,
+				  data, end - data);
+		if (len < 0) return len;
+
+		if (len == 0) break; /* insufficient room to encode it */
+
+		data += data[1];
+	}
+
+#ifdef PW_MESSAGE_AUTHENTICATOR
+	/*
+	 *	Always send a Message-Authenticator.
+	 *
+	 *	We do *not* recommend removing this code.
+	 */
+	if (((packet->code == PW_ACCESS_REQUEST) ||
+	     (packet->code == PW_STATUS_SERVER)) &&
+	    !ma &&
+	    ((data + 18) <= end)) {
+		ma = (data - packet->data);
+		data[0] = PW_MESSAGE_AUTHENTICATOR;
+		data[1] = 18;
+		memset(data + 2, 0, 16);
+		data += data[1];
+	}
+#endif
+
+	packet->length = data - packet->data;
+
+	packet->data[2] = (packet->length >> 8) & 0xff;
+	packet->data[3] = packet->length & 0xff;
+
+	packet->flags |= RS_PACKET_ENCODED;
+
+	return packet->length;
+}
+
+
+/*
+ *	Ensure that the nr_data2attr_t structure is filled in
+ *	appropriately.  This includes filling in a fake DICT_ATTR
+ *	structure, if necessary.
+ */
+static int do_callback(void *ctx, nr_packet_walk_func_t callback,
+		       int attr, int vendor,
+		       const uint8_t *data, size_t sizeof_data)
+		       
+{
+	int rcode;
+	const DICT_ATTR *da;
+	DICT_ATTR myda;
+	char buffer[64];
+
+	da = nr_dict_attr_byvalue(attr, vendor);
+
+	/*
+	 *	The attribute is supposed to have a particular length,
+	 *	but does not.  It is therefore malformed.
+	 */
+	if (da && (da->flags.length != 0) &&
+	    da->flags.length != sizeof_data) {
+		da = NULL;
+	}
+
+	if (!da) {
+		rcode = nr_dict_attr_2struct(&myda, attr, vendor,
+					     buffer, sizeof(buffer));
+		
+		if (rcode < 0) return rcode;
+		da = &myda;
+	}
+	
+	rcode = callback(ctx, da, data, sizeof_data);
+	if (rcode < 0) return rcode;
+
+	return 0;
+}
+
+
+int nr_packet_walk(RADIUS_PACKET *packet, void *ctx,
+		   nr_packet_walk_func_t callback)
+{
+	int rcode;
+	uint8_t *attr;
+	const uint8_t *end;
+
+	if (!packet || !callback) return -RSE_INVAL;
+
+	rcode = nr_packet_ok(packet);
+	if (rcode < 0) return rcode;
+
+	end = packet->data + packet->length;
+
+	for (attr = packet->data + 20; attr < end; attr += attr[1]) {
+		int length, value;
+		int dv_type, dv_length;
+		uint32_t vendorpec;
+		const uint8_t *vsa;
+		const DICT_VENDOR *dv = NULL;
+
+		vendorpec = 0;
+		value = attr[0];
+
+		if (value != PW_VENDOR_SPECIFIC) {
+		raw:
+			rcode = do_callback(ctx, callback,
+					    attr[0], 0,
+					    attr + 2, attr[1] - 2);
+			if (rcode < 0) return rcode;
+			continue;
+		}
+
+		if (attr[1] < 6) goto raw;
+		memcpy(&vendorpec, attr + 2, 4);
+		vendorpec = ntohl(vendorpec);
+
+		if (dv && (dv->vendor != vendorpec)) dv = NULL;
+
+		if (!dv) dv = nr_dict_vendor_byvalue(vendorpec);
+
+		if (dv) {
+			dv_type = dv->type;
+			dv_length = dv->length;
+		} else {
+			dv_type = 1;
+			dv_length = 1;
+		}
+
+		/*
+		 *	Malformed: it's a raw attribute.
+		 */
+		if (nr_tlv_ok(attr + 6, attr[1] - 6, dv_type, dv_length) < 0) {
+			goto raw;
+		}
+
+		for (vsa = attr + 6; vsa < attr + attr[1]; vsa += length) {
+			switch (dv_type) {
+			case 4:
+				value = (vsa[2] << 8) | vsa[3];
+				break;
+
+			case 2:
+				value = (vsa[0] << 8) | vsa[1];
+				break;
+
+			case 1:
+				value = vsa[0];
+				break;
+
+			default:
+				return -RSE_INTERNAL;
+			}
+
+			switch (dv_length) {
+			case 0:
+				length = attr[1] - 6 - dv_type;
+				break;
+
+			case 2:
+			case 1:
+				length = vsa[dv_type + dv_length - 1];
+				break;
+
+			default:
+				return -RSE_INTERNAL;
+			}
+
+			rcode = do_callback(ctx, callback,
+					    value, vendorpec,
+					    vsa + dv_type + dv_length,
+					    length - dv_type - dv_length);
+			if (rcode < 0) return rcode;
+		}
+	}
+
+	return 0;
+}
+
+int nr_packet_init(RADIUS_PACKET *packet, const RADIUS_PACKET *original,
+		   const char *secret, int code,
+		   void *data, size_t sizeof_data)
+{
+	int rcode;
+
+	if ((code < 0) || (code > RS_MAX_PACKET_CODE)) {
+		return -RSE_INVALID_REQUEST_CODE;
+	}
+
+	if (!data || (sizeof_data < 20)) return -RSE_INVAL;
+
+	memset(packet, 0, sizeof(*packet));
+	packet->secret = secret;
+	packet->sizeof_secret = secret ? strlen(secret) : 0;
+	packet->code = code;
+	packet->id = 0;
+	packet->data = data;
+	packet->sizeof_data = sizeof_data;
+
+	rcode = can_encode_packet(packet, original);
+	if (rcode < 0) return rcode;
+
+	encode_header(packet);
+
+	return 0;
+}
+
+
+static int pack_eap(RADIUS_PACKET *packet,
+		    const void *data, size_t data_len)
+{
+	uint8_t *attr, *end;
+	const uint8_t *eap;
+	size_t left;
+		
+	eap = data;
+	left = data_len;
+	attr = packet->data + packet->length;
+	end = attr + packet->sizeof_data;
+	
+	while (left > 253) {
+		if ((attr + 255) > end) return -RSE_ATTR_OVERFLOW;
+		
+		attr[0] = PW_EAP_MESSAGE;
+		attr[1] = 255;
+		memcpy(attr + 2, eap, 253);
+		attr += attr[1];
+		eap += 253;
+		left -= 253;
+	}
+	
+	if ((attr + (2 + left)) > end) return -RSE_ATTR_OVERFLOW;
+	
+	attr[0] = PW_EAP_MESSAGE;
+	attr[1] = 2 + left;
+	memcpy(attr + 2, eap, left);
+	attr += attr[1];
+	packet->length = attr - packet->data;
+
+	return 0;
+}
+
+ssize_t nr_packet_attr_append(RADIUS_PACKET *packet,
+			      const RADIUS_PACKET *original,
+			      const DICT_ATTR *da,
+			      const void *data, size_t data_len)
+{
+	ssize_t rcode;
+	uint8_t *attr, *end;
+	VALUE_PAIR my_vp;
+	const VALUE_PAIR *vp;
+
+	if (!packet || !da || !data) {
+		return -RSE_INVAL;
+	}
+
+	if (data_len == 0) {
+		if (da->type != RS_TYPE_STRING) return -RSE_ATTR_TOO_SMALL;
+
+		data_len = strlen(data);
+	}
+
+	packet->flags |= RS_PACKET_ENCODED; /* ignore any VPs */
+
+	attr = packet->data + packet->length;
+	end = attr + packet->sizeof_data;
+
+	if ((attr + 2 + data_len) > end) {
+		return -RSE_ATTR_OVERFLOW;
+	}
+
+	if ((da->flags.length != 0) &&
+	    (data_len != da->flags.length)) {
+		return -RSE_ATTR_VALUE_MALFORMED;
+	}
+
+#ifdef PW_EAP_MESSAGE
+	/*
+	 *	automatically split EAP-Message into multiple
+	 *	attributes.
+	 */
+	if (!da->vendor && (da->attr == PW_EAP_MESSAGE) && (data_len > 253)) {
+		return pack_eap(packet, data, data_len);
+	}
+#endif
+
+	if (data_len > 253) return -RSE_ATTR_TOO_LARGE;
+
+	vp = nr_vp_init(&my_vp, da);
+	rcode = nr_vp_set_data(&my_vp, data, data_len);
+	if (rcode < 0) return rcode;
+
+	/*
+	 *	Note that this function packs VSAs each into their own
+	 *	Vendor-Specific attribute.  If this isn't what you
+	 *	want, use the version of the library with full support
+	 *	for TLVs, WiMAX, and extended attributes.
+	 */
+	rcode = nr_vp2attr(packet, original, &vp, attr, end - attr);
+	if (rcode <= 0) return rcode;
+
+	packet->length += rcode;
+
+	return rcode;
+}