X-Git-Url: http://git.sameswireless.fr/l2tpns.git/blobdiff_plain/eb3a6cd62dc3b83c68ad174d4c439f5bbaa902e1..b61f2884c62ec6b8060453b80a3ae3c1b4770a38:/ppp.c?ds=inline

diff --git a/ppp.c b/ppp.c
index cfd4f80..d1258cf 100644
--- a/ppp.c
+++ b/ppp.c
@@ -1,6 +1,6 @@
 // L2TPNS PPP Stuff
 
-char const *cvs_id_ppp = "$Id: ppp.c,v 1.6 2004/06/28 02:43:13 fred_nerk Exp $";
+char const *cvs_id_ppp = "$Id: ppp.c,v 1.53 2005/05/08 06:28:12 bodea Exp $";
 
 #include <stdio.h>
 #include <string.h>
@@ -17,90 +17,108 @@ char const *cvs_id_ppp = "$Id: ppp.c,v 1.6 2004/06/28 02:43:13 fred_nerk Exp $";
 extern tunnelt *tunnel;
 extern sessiont *session;
 extern radiust *radius;
-extern int tapfd;
+extern int tunfd;
 extern char hostname[];
-extern u32 eth_tx;
+extern uint32_t eth_tx;
 extern time_t time_now;
-extern struct configt *config;
+extern configt *config;
+
+static void initccp(tunnelidt t, sessionidt s);
+static uint8_t *add_lcp_auth(uint8_t *b, int size, int authtype);
 
 // Process PAP messages
-void processpap(tunnelidt t, sessionidt s, u8 * p, u16 l)
+void processpap(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
 {
-	char user[129];
-	char pass[129];
-
+	char user[MAXUSER];
+	char pass[MAXPASS];
+	uint16_t hl;
 
-	CSTAT(call_processpap);
+	CSTAT(processpap);
 
-	log_hex(5, "PAP", p, l);
+	LOG_HEX(5, "PAP", p, l);
 	if (l < 4)
 	{
-		log(1, 0, s, t, "Short PAP %u bytes\n", l);
+		LOG(1, s, t, "Short PAP %u bytes\n", l);
 		STAT(tunnel_rx_errors);
-		return ;
+		sessionshutdown(s, "Short PAP packet.", 3, 0);
+		return;
 	}
-	if (*p != 1)
+
+	if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
 	{
-		log(1, 0, s, t, "Unexpected PAP code %d\n", *p);
+		LOG(1, s, t, "Length mismatch PAP %u/%u\n", hl, l);
 		STAT(tunnel_rx_errors);
-		return ;
+		sessionshutdown(s, "PAP length mismatch.", 3, 0);
+		return;
 	}
-	if (ntohs(*(u16 *) (p + 2)) > l)
+	l = hl;
+
+	if (*p != 1)
 	{
-		log(1, 0, s, t, "Length mismatch PAP %d/%d\n", ntohs(*(u16 *) (p + 2)), l);
+		LOG(1, s, t, "Unexpected PAP code %d\n", *p);
 		STAT(tunnel_rx_errors);
-		return ;
+		sessionshutdown(s, "Unexpected PAP code.", 3, 0);
+		return;
 	}
+
 	{
-		u8 *b = p;
+		uint8_t *b = p;
 		b += 4;
+		user[0] = pass[0] = 0;
 		if (*b && *b < sizeof(user))
+		{
 			memcpy(user, b + 1, *b);
-		user[*b] = 0;
-		b += 1 + *b;
-		if (*b && *b < sizeof(pass))
-			memcpy(pass, b + 1, *b);
-		pass[*b] = 0;
-		log(3, 0, s, t, "PAP login %s/%s\n", user, pass);
+			user[*b] = 0;
+			b += 1 + *b;
+			if (*b && *b < sizeof(pass))
+			{
+				memcpy(pass, b + 1, *b);
+				pass[*b] = 0;
+			}
+		}
+		LOG(3, s, t, "PAP login %s/%s\n", user, pass);
 	}
-	if (session[s].ip || !session[s].radius)
+	if (session[s].ip || !sess_local[s].radius)
 	{
 		// respond now, either no RADIUS available or already authenticated
-		u8 b[MAXCONTROL];
-		u8 id = p[1];
-		u8 *p = makeppp(b, sizeof(b), 0, 0, t, s, PPPPAP);
-		if (!p) {	// Failed to make ppp header!
-			log(1,0,0,0, "Failed to make PPP header in process pap!\n");
-			return;
-		}
+		uint8_t b[MAXCONTROL];
+		uint8_t id = p[1];
+		uint8_t *p = makeppp(b, sizeof(b), 0, 0, t, s, PPPPAP);
+		if (!p) return;
+
 		if (session[s].ip)
-			*p = 2;              // ACK
+			*p = 2;				// ACK
 		else
-			*p = 3;              // cant authorise
+			*p = 3;				// cant authorise
 		p[1] = id;
-		*(u16 *) (p + 2) = htons(5); // length
-		p[4] = 0;               // no message
+		*(uint16_t *) (p + 2) = htons(5);	// length
+		p[4] = 0;				// no message
 		if (session[s].ip)
 		{
-		    log(3, session[s].ip, s, t, "%d Already an IP allocated: %s (%d)\n", getpid(), inet_toa(htonl(session[s].ip)), session[s].ip_pool_index);
+			LOG(3, s, t, "Already an IP allocated: %s (%d)\n",
+				fmtaddr(htonl(session[s].ip), 0), session[s].ip_pool_index);
+
+			session[s].flags &= ~SF_IPCP_ACKED;
 		}
 		else
 		{
-		    log(1, 0, s, t, "No radius session available to authenticate session...\n");
+			LOG(1, s, t, "No radius session available to authenticate session...\n");
 		}
-		log(3, 0, s, t, "Fallback response to PAP (%s)\n", (session[s].ip) ? "ACK" : "NAK");
+		LOG(3, s, t, "Fallback response to PAP (%s)\n", (session[s].ip) ? "ACK" : "NAK");
 		tunnelsend(b, 5 + (p - b), t); // send it
+		sessionshutdown(s, "PAP authentication failed.", 3, 0);
 	}
 	else
-	{                          // set up RADIUS request
-		u16 r = session[s].radius;
+	{
+		// set up RADIUS request
+		uint16_t r = sess_local[s].radius;
 
 		// Run PRE_AUTH plugins
 		struct param_pre_auth packet = { &tunnel[t], &session[s], strdup(user), strdup(pass), PPPPAP, 1 };
 		run_plugins(PLUGIN_PRE_AUTH, &packet);
 		if (!packet.continue_auth)
 		{
-			log(3, 0, s, t, "A plugin rejected PRE_AUTH\n");
+			LOG(3, s, t, "A plugin rejected PRE_AUTH\n");
 			if (packet.username) free(packet.username);
 			if (packet.password) free(packet.password);
 			return;
@@ -113,76 +131,96 @@ void processpap(tunnelidt t, sessionidt s, u8 * p, u16 l)
 		free(packet.password);
 
 		radius[r].id = p[1];
-		log(3, 0, s, t, "Sending login for %s/%s to radius\n", user, pass);
+		LOG(3, s, t, "Sending login for %s/%s to radius\n", user, pass);
 		radiussend(r, RADIUSAUTH);
 	}
 }
 
 // Process CHAP messages
-void processchap(tunnelidt t, sessionidt s, u8 * p, u16 l)
+void processchap(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
 {
-	u16 r;
-	u16 len;
-
+	uint16_t r;
+	uint16_t hl;
 
-	CSTAT(call_processchap);
+	CSTAT(processchap);
 
-	log_hex(5, "CHAP", p, l);
-	r = session[s].radius;
+	LOG_HEX(5, "CHAP", p, l);
+	r = sess_local[s].radius;
 	if (!r)
 	{
-		log(1, 0, s, t, "Unexpected CHAP message\n");
-
-// FIXME: Need to drop the session here.
+		LOG(1, s, t, "Unexpected CHAP message\n");
+		STAT(tunnel_rx_errors);
+		sessionshutdown(s, "Unexpected CHAP message.", 3, 0);
+		return;
+	}
 
+	if (l < 4)
+	{
+		LOG(1, s, t, "Short CHAP %u bytes\n", l);
 		STAT(tunnel_rx_errors);
+		sessionshutdown(s, "Short CHAP packet.", 3, 0);
 		return;
 	}
-	if (*p != 2)
+
+	if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
 	{
-		log(1, 0, s, t, "Unexpected CHAP response code %d\n", *p);
+		LOG(1, s, t, "Length mismatch CHAP %u/%u\n", hl, l);
 		STAT(tunnel_rx_errors);
+		sessionshutdown(s, "CHAP length mismatch.", 3, 0);
 		return;
 	}
-	if (p[1] != radius[r].id)
+	l = hl;
+
+	if (*p != 2)
 	{
-		log(1, 0, s, t, "Wrong CHAP response ID %d (should be %d) (%d)\n", p[1], radius[r].id, r);
+		LOG(1, s, t, "Unexpected CHAP response code %d\n", *p);
 		STAT(tunnel_rx_errors);
-		return ;
+		sessionshutdown(s, "CHAP length mismatch.", 3, 0);
+		return;
 	}
-	len = ntohs(*(u16 *) (p + 2));
-	if (len > l)
+	if (p[1] != radius[r].id)
 	{
-		log(1, 0, s, t, "Bad CHAP length %d\n", len);
+		LOG(1, s, t, "Wrong CHAP response ID %d (should be %d) (%d)\n", p[1], radius[r].id, r);
 		STAT(tunnel_rx_errors);
-		return ;
+		sessionshutdown(s, "Unexpected CHAP response ID.", 3, 0);
+		return;
 	}
-	if (p[4] != 16)
+
+	if (l < 5 || p[4] != 16)
 	{
-		log(1, 0, s, t, "Bad CHAP response length %d\n", p[4]);
+		LOG(1, s, t, "Bad CHAP response length %d\n", l < 5 ? -1 : p[4]);
 		STAT(tunnel_rx_errors);
-		return ;
+		sessionshutdown(s, "Bad CHAP response length.", 3, 0);
+		return;
 	}
-	if (len - 21 >= sizeof(session[s].user))
+
+	l -= 5;
+	p += 5;
+	if (l < 16 || l - 16 >= sizeof(session[s].user))
 	{
-		log(1, 0, s, t, "CHAP user too long %d\n", len - 21);
+		LOG(1, s, t, "CHAP user too long %d\n", l - 16);
 		STAT(tunnel_rx_errors);
-		return ;
+		sessionshutdown(s, "CHAP username too long.", 3, 0);
+		return;
 	}
 
 	// Run PRE_AUTH plugins
 	{
 		struct param_pre_auth packet = { &tunnel[t], &session[s], NULL, NULL, PPPCHAP, 1 };
 
-		packet.username = calloc(len-20, 1);
-		packet.password = calloc(16, 1);
-		memcpy(packet.username, p + 21, len - 21);
-		memcpy(packet.password, p + 5, 16);
+		packet.password = calloc(17, 1);
+		memcpy(packet.password, p, 16);
+
+		p += 16;
+		l -= 16;
+
+		packet.username = calloc(l + 1, 1);
+		memcpy(packet.username, p, l);
 
 		run_plugins(PLUGIN_PRE_AUTH, &packet);
 		if (!packet.continue_auth)
 		{
-			log(3, 0, s, t, "A plugin rejected PRE_AUTH\n");
+			LOG(3, s, t, "A plugin rejected PRE_AUTH\n");
 			if (packet.username) free(packet.username);
 			if (packet.password) free(packet.password);
 			return;
@@ -196,33 +234,18 @@ void processchap(tunnelidt t, sessionidt s, u8 * p, u16 l)
 	}
 
 	radius[r].chap = 1;
-	log(3, 0, s, t, "CHAP login %s\n", session[s].user);
+	LOG(3, s, t, "CHAP login %s\n", session[s].user);
 	radiussend(r, RADIUSAUTH);
 }
 
-char *ppp_lcp_types[] = {
-	NULL,
-	"ConfigReq",
-	"ConfigAck",
-	"ConfigNak",
-	"ConfigRej",
-	"TerminateReq",
-	"TerminateAck",
-	"CodeRej",
-	"ProtocolRej",
-	"EchoReq",
-	"EchoReply",
-	"DiscardRequest",
-};
-
-void dumplcp(u8 *p, int l)
+static void dumplcp(uint8_t *p, int l)
 {
-	signed int x = l - 4;
-	u8 *o = (p + 4);
+	int x = l - 4;
+	uint8_t *o = (p + 4);
 
-	log_hex(5, "PPP LCP Packet", p, l);
-	log(4, 0, 0, 0, "PPP LCP Packet type %d (%s len %d)\n", *p, ppp_lcp_types[(int)*p], ntohs( ((u16 *) p)[1]) );
-	log(4, 0, 0, 0, "Length: %d\n", l);
+	LOG_HEX(5, "PPP LCP Packet", p, l);
+	LOG(4, 0, 0, "PPP LCP Packet type %d (%s len %d)\n", *p, ppp_lcp_type((int)*p), ntohs( ((uint16_t *) p)[1]) );
+	LOG(4, 0, 0, "Length: %d\n", l);
 	if (*p != ConfigReq && *p != ConfigRej && *p != ConfigAck)
 		return;
 
@@ -230,14 +253,14 @@ void dumplcp(u8 *p, int l)
 	{
 		int type = o[0];
 		int length = o[1];
-		if (length == 0)
+		if (length < 2)
 		{
-			log(4, 0, 0, 0, "	Option length is 0...\n");
+			LOG(4, 0, 0, "	Option length is %d...\n", length);
 			break;
 		}
 		if (type == 0)
 		{
-			log(4, 0, 0, 0, "	Option type is 0...\n");
+			LOG(4, 0, 0, "	Option type is 0...\n");
 			x -= length;
 			o += length;
 			continue;
@@ -245,41 +268,58 @@ void dumplcp(u8 *p, int l)
 		switch (type)
 		{
 			case 1: // Maximum-Receive-Unit
-				log(4, 0, 0, 0, "    %s %d\n", lcp_types[type], ntohs(*(u16 *)(o + 2)));
+				if (length == 4)
+					LOG(4, 0, 0, "    %s %d\n", lcp_type(type), ntohs(*(uint16_t *)(o + 2)));
+				else
+					LOG(4, 0, 0, "    %s odd length %d\n", lcp_type(type), length);
+				break;
+			case 2: // Async-Control-Character-Map
+				if (length == 6)
+				{
+					uint32_t asyncmap = ntohl(*(uint32_t *)(o + 2));
+					LOG(4, 0, 0, "    %s %x\n", lcp_type(type), asyncmap);
+				}
+				else
+					LOG(4, 0, 0, "   %s odd length %d\n", lcp_type(type), length);
 				break;
 			case 3: // Authentication-Protocol
+				if (length == 4)
 				{
-					int proto = ntohs(*(u16 *)(o + 2));
-					log(4, 0, 0, 0, "    %s %s\n", lcp_types[type],
-							proto == 0xC223 ? "CHAP" : "PAP");
-					break;
+					int proto = ntohs(*(uint16_t *)(o + 2));
+					LOG(4, 0, 0, "   %s 0x%x (%s)\n", lcp_type(type), proto,
+						proto == PPPPAP  ? "PAP"  : "UNSUPPORTED");
+				}
+				else if (length == 5)
+				{
+					int proto = ntohs(*(uint16_t *)(o + 2));
+					int algo = *(uint8_t *)(o + 4);
+					LOG(4, 0, 0, "   %s 0x%x 0x%x (%s)\n", lcp_type(type), proto, algo,
+						(proto == PPPCHAP && algo == 5) ? "CHAP MD5"  : "UNSUPPORTED");
 				}
+				else
+					LOG(4, 0, 0, "   %s odd length %d\n", lcp_type(type), length);
+				break;
 			case 4: // Quality-Protocol
 				{
-					u32 qp = ntohl(*(u32 *)(o + 2));
-					log(4, 0, 0, 0, "    %s %x\n", lcp_types[type], qp);
-					break;
+					uint32_t qp = ntohl(*(uint32_t *)(o + 2));
+					LOG(4, 0, 0, "    %s %x\n", lcp_type(type), qp);
 				}
+				break;
 			case 5: // Magic-Number
+				if (length == 6)
 				{
-					u32 magicno = ntohl(*(u32 *)(o + 2));
-					log(4, 0, 0, 0, "    %s %x\n", lcp_types[type], magicno);
-					break;
+					uint32_t magicno = ntohl(*(uint32_t *)(o + 2));
+					LOG(4, 0, 0, "    %s %x\n", lcp_type(type), magicno);
 				}
+				else
+					LOG(4, 0, 0, "   %s odd length %d\n", lcp_type(type), length);
+				break;
 			case 7: // Protocol-Field-Compression
-				{
-					u32 pfc = ntohl(*(u32 *)(o + 2));
-					log(4, 0, 0, 0, "    %s %x\n", lcp_types[type], pfc);
-					break;
-				}
 			case 8: // Address-And-Control-Field-Compression
-				{
-					u32 afc = ntohl(*(u32 *)(o + 2));
-					log(4, 0, 0, 0, "    %s %x\n", lcp_types[type], afc);
-					break;
-				}
+				LOG(4, 0, 0, "    %s\n", lcp_type(type));
+				break;
 			default:
-				log(2, 0, 0, 0, "    Unknown PPP LCP Option type %d\n", type);
+				LOG(2, 0, 0, "    Unknown PPP LCP Option type %d\n", type);
 				break;
 		}
 		x -= length;
@@ -288,183 +328,371 @@ void dumplcp(u8 *p, int l)
 }
 
 // Process LCP messages
-void processlcp(tunnelidt t, sessionidt s, u8 * p, u16 l)
+void processlcp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
 {
-	u8 b[MAXCONTROL];
-	u8 *q = NULL;
+	uint8_t b[MAXCONTROL];
+	uint8_t *q = NULL;
+	uint32_t magicno = 0;
+	uint16_t hl;
 
+	CSTAT(processlcp);
 
-	CSTAT(call_processlcp);
-
-	log_hex(5, "LCP", p, l);
+	LOG_HEX(5, "LCP", p, l);
 	if (l < 4)
 	{
-		log(1, session[s].ip, s, t, "Short LCP %d bytes\n", l);
+		LOG(1, s, t, "Short LCP %d bytes\n", l);
+		STAT(tunnel_rx_errors);
+		return ;
+	}
+
+	if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
+	{
+		LOG(1, s, t, "Length mismatch LCP %u/%u\n", hl, l);
 		STAT(tunnel_rx_errors);
 		return ;
 	}
+	l = hl;
+
 	if (*p == ConfigAck)
 	{
-		log(3, session[s].ip, s, t, "LCP: Discarding ConfigAck\n");
+		LOG(3, s, t, "LCP: Discarding ConfigAck\n");
+		session[s].flags |= SF_LCP_ACKED;
 	}
 	else if (*p == ConfigReq)
 	{
-		signed int x = l - 4;
-		u8 *o = (p + 4);
+		int x = l - 4;
+		uint8_t *o = (p + 4);
+		uint8_t *response = 0;
 
-		log(3, session[s].ip, s, t, "LCP: ConfigReq (%d bytes)...\n", l);
-		dumplcp(p, l);
+		LOG(3, s, t, "LCP: ConfigReq (%d bytes)...\n", l);
+		if (config->debug > 3) dumplcp(p, l);
 
 		while (x > 2)
 		{
 			int type = o[0];
 			int length = o[1];
-			if (length == 0 || type == 0) break;
+
+			if (length == 0 || type == 0 || x < length) break;
 			switch (type)
 			{
 				case 1: // Maximum-Receive-Unit
-					session[s].mru = ntohs(*(u16 *)(o + 2));
+					session[s].mru = ntohs(*(uint16_t *)(o + 2));
 					break;
+
+				case 2: // Async-Control-Character-Map
+					if (!ntohl(*(uint32_t *)(o + 2))) // all bits zero is OK
+						break;
+
+					if (response && *response != ConfigNak) // rej already queued
+						break;
+
+					LOG(2, s, t, "    Remote requesting asyncmap.  Rejecting.\n");
+					if (!response)
+					{
+						q = response = makeppp(b, sizeof(b), p, 2, t, s, PPPLCP);
+						if (!q) break;
+						*q = ConfigNak;
+						q += 4;
+					}
+
+					if ((q - b + 11) > sizeof(b))
+					{
+						LOG(2, s, t, "LCP overflow for asyncmap ConfigNak.\n");
+						break;
+					}
+
+					*q++ = type;
+					*q++ = 6;
+					memset(q, 0, 4); // asyncmap 0
+					q += 4;
+					*((uint16_t *) (response + 2)) = htons(q - response); // LCP header length
+					break;
+
 				case 3: // Authentication-Protocol
 					{
-						int proto = ntohs(*(u16 *)(o + 2));
-						if (proto == 0xC223)
+						int proto = ntohs(*(uint16_t *)(o + 2));
+						char proto_name[] = "0x0000";
+						uint8_t *a;
+
+						if (proto == PPPPAP)
+						{
+							if (config->radius_authtypes & AUTHPAP)
+								break;
+
+							strcpy(proto_name, "PAP");
+						}
+						else if (proto == PPPCHAP)
 						{
-							log(2, session[s].ip, s, t, "    Remote end is trying to do CHAP. Rejecting it.\n");
+							if (config->radius_authtypes & AUTHCHAP
+							    && *(o + 4) == 5) // MD5
+								break;
+
+							strcpy(proto_name, "CHAP");
+						}
+						else
+							sprintf(proto_name, "%#4.4x", proto);
+
+						if (response && *response != ConfigNak) // rej already queued
+							break;
+
+						LOG(2, s, t, "    Remote requesting %s authentication.  Rejecting.\n", proto_name);
+
+						if (!response)
+						{
+							q = response = makeppp(b, sizeof(b), p, 2, t, s, PPPLCP);
+							if (!q) break;
+							*q = ConfigNak;
+							q += 4;
+						}
 
-							if (!q)
+						a = add_lcp_auth(q, sizeof(b) - (q - b), config->radius_authprefer);
+						if (!a)
+						{
+							LOG(2, s, t, "LCP overflow for %s ConfigNak.\n", proto_name);
+							break;
+						}
+
+						q = a;
+
+						if (config->radius_authtypes != config->radius_authprefer)
+						{
+							a = add_lcp_auth(q, sizeof(b) - (q - b), config->radius_authtypes & ~config->radius_authprefer);
+							if (!a)
 							{
-								q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
-								if (!q) {
-									log(2, session[s].ip, s, t, " Failed to send packet.\n");
-									break;
-								}
-								*q++ = ConfigNak;
+								LOG(2, s, t, "LCP overflow for %s ConfigNak.\n", proto_name);
+								break;
 							}
-							memcpy(q, o, length);
-							*(u16 *)(q += 2) = htons(0xC023); // NAK -> Use PAP instead
-							q += length;
+
+							q = a;
 						}
+
+						*((uint16_t *) (response + 2)) = htons(q - response); // LCP header length
 						break;
 					}
+					break;
+
 				case 5: // Magic-Number
-					{
-//						u32 magicno = ntohl(*(u32 *)(o + 2));
-						break;
-					}
+					magicno = ntohl(*(uint32_t *)(o + 2));
+					break;
+
 				case 4: // Quality-Protocol
-					{
-//						u32 qp = ntohl(*(u32 *)(o + 2));
-						break;
-					}
 				case 7: // Protocol-Field-Compression
+				case 8: // Address-And-Control-Field-Compression
+					break;
+
+				default: // Reject any unknown options
+					LOG(2, s, t, "    Rejecting PPP LCP Option type %d\n", type);
+					if (!response || *response != ConfigRej) // drop nak in favour of rej
 					{
-//						u32 pfc = ntohl(*(u32 *)(o + 2));
-						break;
+						q = response = makeppp(b, sizeof(b), p, 2, t, s, PPPLCP);
+						if (!q) break;
+						*q = ConfigRej;
+						q += 4;
 					}
-				case 8: // Address-And-Control-Field-Compression
+
+					if ((q - b + length) > sizeof(b))
 					{
-//						u32 afc = ntohl(*(u32 *)(o + 2));
+						LOG(2, s, t, "LCP overflow for ConfigRej (type=%d).\n", type);
 						break;
 					}
-				default:
-					log(2, session[s].ip, s, t, "    Unknown PPP LCP Option type %d\n", type);
-					break;
+
+					memcpy(q, o, length);
+					q += length;
+					*((uint16_t *) (response + 2)) = htons(q - response); // LCP header length
 			}
 			x -= length;
 			o += length;
 		}
 
-		if (!q)
+		if (!response)
 		{
 			// Send back a ConfigAck
-			log(3, session[s].ip, s, t, "ConfigReq accepted, sending as Ack\n");
-			q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
-			if (!q) {
-				log(3, session[s].ip, s, t, " failed to create packet.\n");
-				return;
-			}
+			q = response = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
+			if (!q) return;
 			*q = ConfigAck;
-			tunnelsend(b, l + (q - b), t);
-		}
-		else
-		{
-			// Already built a ConfigNak... send it
-			log(3, session[s].ip, s, t, "Sending ConfigNak\n");
-			tunnelsend(b, l + (q - b), t);
-
-			log(3, session[s].ip, s, t, "Sending ConfigReq, requesting PAP login\n");
-			q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP);
-			*q++ = ConfigReq;
-			*(u8 *)(q++) = 3;
-			*(u8 *)(q++) = 4;
-			*(u16 *)(q += 2) = htons(0xC023);
-			tunnelsend(b, l + (q - b), t);
 		}
+
+		LOG(3, s, t, "Sending %s\n", ppp_lcp_type(*response));
+		tunnelsend(b, l + (q - b), t);
+
+		if (!(session[s].flags & SF_LCP_ACKED))
+			sendlcp(t, s, config->radius_authprefer);
 	}
 	else if (*p == ConfigNak)
 	{
-		log(1, session[s].ip, s, t, "Remote end sent a ConfigNak. Ignoring\n");
-		dumplcp(p, l);
-		return ;
+		int x = l - 4;
+		uint8_t *o = (p + 4);
+		int authtype = 0;
+
+		LOG(3, s, t, "LCP: ConfigNak (%d bytes)...\n", l);
+		if (config->debug > 3) dumplcp(p, l);
+
+		while (x > 2)
+		{
+			int type = o[0];
+			int length = o[1];
+
+			if (length == 0 || type == 0 || x < length) break;
+			switch (type)
+			{
+				case 1: // Maximum-Receive-Unit
+					session[s].mru = ntohs(*(uint16_t *)(o + 2));
+					LOG(3, s, t, "    Remote requested MRU of %u\n", session[s].mru);
+					break;
+
+				case 3: // Authentication-Protocol
+					if (authtype)
+						break;
+
+					{
+						int proto = ntohs(*(uint16_t *)(o + 2));
+						if (proto == PPPPAP)
+						{
+							authtype = config->radius_authtypes & AUTHPAP;
+							LOG(3, s, t, "    Remote requested PAP authentication...%sing\n",
+								authtype ? "accept" : "reject");
+						}
+						else if (proto == PPPCHAP && *(o + 4) == 5)
+						{
+							authtype = config->radius_authtypes & AUTHCHAP;
+							LOG(3, s, t, "    Remote requested CHAP authentication...%sing\n",
+								authtype ? "accept" : "reject");
+						}
+						else
+						{
+							LOG(3, s, t, "    Rejecting unsupported authentication %#4x\n",
+								proto);
+						}
+					}
+
+					if (!authtype)
+					{
+						sessionshutdown(s, "Unsupported authentication.", 3, 0);
+						return;
+					}
+
+					break;
+
+				default:
+				    	LOG(2, s, t, "    Remote NAKed LCP type %u?\n", type);
+					break;
+			}
+		}
+
+		if (!authtype)
+			authtype = config->radius_authprefer;
+
+		sendlcp(t, s, authtype);
 	}
 	else if (*p == TerminateReq)
 	{
-		*p = TerminateAck;     // close
+		LOG(3, s, t, "LCP: Received TerminateReq.  Sending TerminateAck\n");
+		*p = TerminateAck;	// close
 		q = makeppp(b, sizeof(b),  p, l, t, s, PPPLCP);
-		if (!q) {
-			log(3, session[s].ip, s, t, "Failed to create PPP packet in processlcp.\n");
-			return;
-		}
-		log(3, session[s].ip, s, t, "LCP: Received TerminateReq. Sending TerminateAck\n");
-		sessionshutdown(s, "Remote end closed connection.");
+		if (!q) return;
 		tunnelsend(b, l + (q - b), t); // send it
+		sessionshutdown(s, "Remote end closed connection.", 3, 0);
 	}
-	else if (*p == TerminateReq)
+	else if (*p == TerminateAck)
 	{
-		sessionshutdown(s, "Remote end closed connection.");
+		sessionshutdown(s, "Connection closed.", 3, 0);
+	}
+	else if (*p == ProtocolRej)
+	{
+		if (*(uint16_t *) (p+4) == htons(PPPIPV6CP))
+		{
+			LOG(3, s, t, "IPv6 rejected\n");
+			session[s].flags |= SF_IPV6_NACKED;
+		}
+		else
+		{
+			LOG(1, s, t, "Unexpected LCP protocol reject 0x%X\n",
+				ntohs(*(uint16_t *) (p+4)));
+			STAT(tunnel_rx_errors);
+		}
 	}
 	else if (*p == EchoReq)
 	{
-		*p = EchoReply;      // reply
-		*(u32 *) (p + 4) = htonl(session[s].magic); // our magic number
+		LOG(5, s, t, "LCP: Received EchoReq.  Sending EchoReply\n");
+		*p = EchoReply;		// reply
+		*(uint32_t *) (p + 4) = htonl(session[s].magic); // our magic number
 		q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
-		if (!q) {
-			log(3, session[s].ip, s, t, " failed to send EchoReply.\n");
-			return;
-		}
-		log(5, session[s].ip, s, t, "LCP: Received EchoReq. Sending EchoReply\n");
+		if (!q) return;
 		tunnelsend(b, l + (q - b), t); // send it
 	}
 	else if (*p == EchoReply)
 	{
 		// Ignore it, last_packet time is set earlier than this.
 	}
+	else if (*p == IdentRequest)
+	{
+		*p = CodeRej;
+		if (l > MAXCONTROL)
+		{
+			LOG(1, s, t, "Truncated Ident Packet (length=%d) to 1400 bytes\n", l);
+			l = 1400;
+		}
+		q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
+		if (!q) return;
+		LOG_HEX(5, "LCPIdentRej", q, l + 4);
+		tunnelsend(b, 12 + 4 + l, t);
+	}
 	else
 	{
-		log(1, session[s].ip, s, t, "Unexpected LCP code %d\n", *p);
+		LOG(1, s, t, "Unexpected LCP code %d\n", *p);
 		STAT(tunnel_rx_errors);
-		return ;
 	}
 }
 
+// find a PPP option, returns point to option, or 0 if not found
+static uint8_t *findppp(uint8_t *b, uint8_t mtype)
+{
+	uint16_t l = ntohs(*(uint16_t *) (b + 2));
+	if (l < 4)
+		return 0;
+	b += 4;
+	l -= 4;
+	while (l)
+	{
+		if (l < b[1] || !b[1])
+			return 0;		// faulty
+		if (*b == mtype)
+			return b;
+		l -= b[1];
+		b += b[1];
+	}
+	return 0;
+}
+
 // Process IPCP messages
-void processipcp(tunnelidt t, sessionidt s, u8 * p, u16 l)
+void processipcp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
 {
+	uint16_t hl;
 
-	CSTAT(call_processipcp);
+	CSTAT(processipcp);
 
-	log_hex(5, "IPCP", p, l);
+	LOG_HEX(5, "IPCP", p, l);
 	if (l < 5)
 	{
-		log(1, 0, s, t, "Short IPCP %d bytes\n", l);
+		LOG(1, s, t, "Short IPCP %d bytes\n", l);
 		STAT(tunnel_rx_errors);
 		return ;
 	}
+
+	if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
+	{
+		LOG(1, s, t, "Length mismatch IPCP %u/%u\n", hl, l);
+		STAT(tunnel_rx_errors);
+		return ;
+	}
+	l = hl;
+
 	if (*p == ConfigAck)
-	{                          // happy with our IPCP
-		u16 r = session[s].radius;
-		if ((!r || radius[r].state == RADIUSIPCP) && !session[s].walled_garden) {
+	{
+		// happy with our IPCP
+		uint16_t r = sess_local[s].radius;
+		if ((!r || radius[r].state == RADIUSIPCP) && !session[s].walled_garden)
+		{
 			if (!r)
 				r = radiusnew(s);
 			if (r)
@@ -472,30 +700,30 @@ void processipcp(tunnelidt t, sessionidt s, u8 * p, u16 l)
 		}
 		session[s].flags |= SF_IPCP_ACKED;
 
-		return ;                 // done
+		LOG(3, s, t, "IPCP Acked, session is now active\n");
+
+		// clear LCP_ACKED/CCP_ACKED flag for possible fast renegotiaion for routers
+		session[s].flags &= ~(SF_LCP_ACKED|SF_CCP_ACKED);
+
+		return;
 	}
 	if (*p != ConfigReq)
 	{
-		log(1, 0, s, t, "Unexpected IPCP code %d\n", *p);
-		STAT(tunnel_rx_errors);
-		return ;
-	}
-	if (ntohs(*(u16 *) (p + 2)) > l)
-	{
-		log(1, 0, s, t, "Length mismatch IPCP %d/%d\n", ntohs(*(u16 *) (p + 2)), l);
+		LOG(1, s, t, "Unexpected IPCP code %d\n", *p);
 		STAT(tunnel_rx_errors);
 		return ;
 	}
+	LOG(4, s, t, "IPCP ConfigReq received\n");
+
 	if (!session[s].ip)
 	{
-		log(3, 0, s, t, "Waiting on radius reply\n");
-		return ;                   // have to wait on RADIUS reply
+		LOG(3, s, t, "Waiting on radius reply\n");
+		return;			// have to wait on RADIUS reply
 	}
 	// form a config reply quoting the IP in the session
 	{
-		u8 b[MAXCONTROL];
-		u8 *i,
-		*q;
+		uint8_t b[MAXCONTROL];
+		uint8_t *i, *q;
 
 		q = p + 4;
 		i = p + l;
@@ -506,65 +734,190 @@ void processipcp(tunnelidt t, sessionidt s, u8 * p, u16 l)
 			q += q[1];
 		}
 		if (q < i)
-		{                       // reject
-			u16 n = 4;
+		{
+			// reject
+			uint16_t n = 4;
 			i = p + l;
-			q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP);
-			if (!q) {
-				log(2, 0, s, t, "Failed to send IPCP.\n");
+			if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))
 				return;
-			}
+
 			*q = ConfigRej;
 			p += 4;
 			while (p < i && p[1])
 			{
 				if (*p != 0x81 && *p != 0x83 && *p != 3)
 				{
-					log(2, 0, s, t, "IPCP reject %d\n", *p);
+					LOG(2, s, t, "IPCP reject %d\n", *p);
 					memcpy(q + n, p, p[1]);
 					n += p[1];
 				}
 				p += p[1];
 			}
-			*(u16 *) (q + 2) = htons(n);
+			*(uint16_t *) (q + 2) = htons(n);
+			LOG(4, s, t, "Sending ConfigRej\n");
 			tunnelsend(b, n + (q - b), t); // send it
 		}
 		else
 		{
+			LOG(4, s, t, "Sending ConfigAck\n");
 			*p = ConfigAck;
-			i = findppp(p, 0x81); // Primary DNS address
-			if (i)
+			if ((i = findppp(p, 0x81))) // Primary DNS address
 			{
-				if (*(u32 *) (i + 2) != htonl(session[s].dns1))
+				if (*(uint32_t *) (i + 2) != htonl(session[s].dns1))
 				{
-					*(u32 *) (i + 2) = htonl(session[s].dns1);
+					*(uint32_t *) (i + 2) = htonl(session[s].dns1);
 					*p = ConfigNak;
+					LOG(5, s, t, "   DNS1 = %s\n",
+						fmtaddr(htonl(session[s].dns1), 0));
 				}
 			}
-			i = findppp(p, 0x83); // Secondary DNS address (TBA, is it)
-			if (i)
+			if ((i = findppp(p, 0x83))) // Secondary DNS address (TBA, is it)
 			{
-				if (*(u32 *) (i + 2) != htonl(session[s].dns2))
+				if (*(uint32_t *) (i + 2) != htonl(session[s].dns2))
 				{
-					*(u32 *) (i + 2) = htonl(session[s].dns2);
+					*(uint32_t *) (i + 2) = htonl(session[s].dns2);
 					*p = ConfigNak;
+					LOG(5, s, t, "   DNS2 = %s\n",
+						fmtaddr(htonl(session[s].dns2), 0));
 				}
 			}
-			i = findppp(p, 3);   // IP address
+			i = findppp(p, 3);		// IP address
 			if (!i || i[1] != 6)
 			{
-				log(1, 0, s, t, "No IP in IPCP request\n");
+				LOG(1, s, t, "No IP in IPCP request\n");
 				STAT(tunnel_rx_errors);
 				return ;
 			}
-			if (*(u32 *) (i + 2) != htonl(session[s].ip))
+			if (*(uint32_t *) (i + 2) != htonl(session[s].ip))
 			{
-				*(u32 *) (i + 2) = htonl(session[s].ip);
+				*(uint32_t *) (i + 2) = htonl(session[s].ip);
 				*p = ConfigNak;
+				LOG(4, s, t, " No, a ConfigNak, client is requesting IP - sending %s\n",
+						fmtaddr(htonl(session[s].ip), 0));
 			}
-			q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP);
-			if (!q) {
-				log(2, 0, s, t, " Failed to send IPCP packet.\n");
+			if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))
+				return;
+
+			tunnelsend(b, l + (q - b), t); // send it
+		}
+	}
+}
+
+// Process IPV6CP messages
+void processipv6cp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
+{
+
+	CSTAT(processipv6cp);
+
+	LOG_HEX(5, "IPV6CP", p, l);
+	if (l < 4)
+	{
+		LOG(1, s, t, "Short IPV6CP %d bytes\n", l);
+		STAT(tunnel_rx_errors);
+		return ;
+	}
+	if (*p == ConfigAck)
+	{
+		// happy with our IPV6CP
+		session[s].flags |= SF_IPV6CP_ACKED;
+
+		LOG(3, s, t, "IPV6CP Acked, IPv6 is now active\n");
+		// Add a routed block if configured.
+		if (session[s].ipv6prefixlen)
+		{
+			route6set(s, session[s].ipv6route, session[s].ipv6prefixlen, 1);
+			session[s].flags |= SF_IPV6_ROUTED;
+		}
+
+		// Send an initial RA (TODO: Should we send these regularly?)
+		send_ipv6_ra(t, s, NULL);
+		return;
+	}
+	if (*p != ConfigReq)
+	{
+		LOG(1, s, t, "Unexpected IPV6CP code %d\n", *p);
+		STAT(tunnel_rx_errors);
+		return;
+	}
+
+	LOG(4, s, t, "IPV6CP ConfigReq received\n");
+	if (ntohs(*(uint16_t *) (p + 2)) > l)
+	{
+		LOG(1, s, t, "Length mismatch IPV6CP %d/%d\n", ntohs(*(uint16_t *) (p + 2)), l);
+		STAT(tunnel_rx_errors);
+		return ;
+	}
+	if (!session[s].ip)
+	{
+		LOG(3, s, t, "Waiting on radius reply\n");
+		return;			// have to wait on RADIUS reply
+	}
+	// form a config reply quoting the IP in the session
+	{
+		uint8_t b[MAXCONTROL];
+		uint8_t *i,
+		*q;
+
+		l = ntohs(*(uint16_t *) (p + 2)); // We must use length from IPV6CP len field
+		q = p + 4;
+		i = p + l;
+		while (q < i && q[1])
+		{
+			if (*q != 1)
+				break;
+			q += q[1];
+		}
+		if (q < i)
+		{
+			// reject
+			uint16_t n = 4;
+			i = p + l;
+			if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPV6CP)))
+			{
+				LOG(2, s, t, "Failed to send IPV6CP ConfigRej\n");
+				return;
+			}
+			*q = ConfigRej;
+			p += 4;
+			while (p < i && p[1])
+			{
+				if (*p != 1)
+				{
+					LOG(2, s, t, "IPV6CP reject %d\n", *p);
+					memcpy(q + n, p, p[1]);
+					n += p[1];
+				}
+				p += p[1];
+			}
+			*(uint16_t *) (q + 2) = htons(n);
+			LOG(4, s, t, "Sending ConfigRej\n");
+			tunnelsend(b, n + (q - b), t); // send it
+		}
+		else
+		{
+			LOG(4, s, t, "Sending ConfigAck\n");
+			*p = ConfigAck;
+			i = findppp(p, 1);		// IP address
+			if (!i || i[1] != 10)
+			{
+				LOG(1, s, t, "No IP in IPV6CP request\n");
+				STAT(tunnel_rx_errors);
+				return ;
+			}
+			if ((*(uint32_t *) (i + 2) != htonl(session[s].ip)) || 
+					(*(uint32_t *) (i + 6) != 0))
+			{
+				*(uint32_t *) (i + 2) = htonl(session[s].ip);
+				*(uint32_t *) (i + 6) = 0;
+				*p = ConfigNak;
+				LOG(4, s, t,
+					" No, a ConfigNak, client is "
+					"requesting IP - sending %s\n",
+					fmtaddr(htonl(session[s].ip), 0));
+			}
+			if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPV6CP)))
+			{
+				LOG(2, s, t, " Failed to send IPV6CP packet.\n");
 				return;
 			}
 			tunnelsend(b, l + (q - b), t); // send it
@@ -576,20 +929,19 @@ void processipcp(tunnelidt t, sessionidt s, u8 * p, u16 l)
 //
 // This MUST be called with at least 4 byte behind 'p'.
 // (i.e. this routine writes to p[-4]).
-void processipin(tunnelidt t, sessionidt s, u8 * p, u16 l)
+void processipin(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
 {
-	ipt ip;
+	in_addr_t ip;
 
+	CSTAT(processipin);
 
-	CSTAT(call_processipin);
+	LOG_HEX(5, "IP", p, l);
 
-	log_hex(5, "IP", p, l);
-
-	ip = ntohl(*(u32 *)(p + 12));
+	ip = ntohl(*(uint32_t *)(p + 12));
 
 	if (l > MAXETHER)
 	{
-		log(1, ip, s, t, "IP packet too long %d\n", l);
+		LOG(1, s, t, "IP packet too long %d\n", l);
 		STAT(tunnel_rx_errors);
 		return ;
 	}
@@ -597,36 +949,117 @@ void processipin(tunnelidt t, sessionidt s, u8 * p, u16 l)
 	// no spoof (do sessionbyip to handled statically routed subnets)
 	if (ip != session[s].ip && sessionbyip(htonl(ip)) != s)
 	{
-		log(5, ip, s, t, "Dropping packet with spoofed IP %s\n", inet_toa(htonl(ip)));
+		LOG(5, s, t, "Dropping packet with spoofed IP %s\n", fmtaddr(htonl(ip), 0));
 		return;
 	}
 
+	// run access-list if any
+	if (session[s].filter_in && !ip_filter(p, l, session[s].filter_in - 1))
+		return;
+
 	// Add on the tun header
 	p -= 4;
-	*(u32 *)p = htonl(0x00000800);
+	*(uint32_t *) p = htonl(PKTIP);
 	l += 4;
 
-	if (session[s].tbf_in && !config->cluster_iam_master) { // Are we throttled and a slave?
-		master_throttle_packet(session[s].tbf_in, p, l); // Pass it to the master for handling.
+	// Are we throttled and a slave?
+	if (session[s].tbf_in && !config->cluster_iam_master) {
+		// Pass it to the master for handling.
+		master_throttle_packet(session[s].tbf_in, p, l);
+		return;
+	}
+
+	// Are we throttled and a master??
+	if (session[s].tbf_in && config->cluster_iam_master) {
+		// Actually handle the throttled packets.
+		tbf_queue_packet(session[s].tbf_in, p, l);
 		return;
 	}
 
+	// send to ethernet
+	if (tun_write(p, l) < 0)
+	{
+		STAT(tun_tx_errors);
+		LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
+			l, strerror(errno), tunfd, p);
+
+		return;
+	}
+
+	if (session[s].snoop_ip && session[s].snoop_port)
+	{
+		// Snooping this session
+		snoop_send_packet(p + 4, l - 4, session[s].snoop_ip, session[s].snoop_port);
+	}
+
 	session[s].cin += l - 4;
 	session[s].total_cin += l - 4;
-	sess_count[s].cin += l - 4;
+	sess_local[s].cin += l - 4;
 
 	session[s].pin++;
 	eth_tx += l - 4;
 
-	if (session[s].snoop_ip && session[s].snoop_port)
+	STAT(tun_tx_packets);
+	INC_STAT(tun_tx_bytes, l - 4);
+}
+
+// process IPv6 packet received
+//
+// This MUST be called with at least 4 byte behind 'p'.
+// (i.e. this routine writes to p[-4]).
+void processipv6in(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
+{
+	struct in6_addr ip;
+	in_addr_t ipv4;
+
+	CSTAT(processipv6in);
+
+	LOG_HEX(5, "IPv6", p, l);
+
+	ip = *(struct in6_addr *) (p + 8);
+	ipv4 = ntohl(*(uint32_t *)(p + 16));
+
+	if (l > MAXETHER)
 	{
-		// Snooping this session, send it to ASIO
-		snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
+		LOG(1, s, t, "IP packet too long %d\n", l);
+		STAT(tunnel_rx_errors);
+		return ;
 	}
-	STAT(tap_tx_packets);
-	INC_STAT(tap_tx_bytes, l);
 
-	if (session[s].tbf_in && config->cluster_iam_master) { // Are we throttled and a master?? actually handle the throttled packets.
+	// no spoof
+	if (ipv4 != session[s].ip && memcmp(&config->ipv6_prefix, &ip, 8) && sessionbyipv6(ip) != s)
+	{
+		char str[INET6_ADDRSTRLEN];
+		LOG(5, s, t, "Dropping packet with spoofed IP %s\n",
+				inet_ntop(AF_INET6, &ip, str, INET6_ADDRSTRLEN));
+		return;
+	}
+
+	// Check if it's a Router Solicition message.
+	if (*(p + 6) == 58 && *(p + 7) == 255 && *(p + 24) == 0xFF && *(p + 25) == 2 &&
+			*(uint32_t *)(p + 26) == 0 && *(uint32_t *)(p + 30) == 0 &&
+			*(uint32_t *)(p + 34) == 0 &&
+			*(p + 38) == 0 && *(p + 39) == 2 && *(p + 40) == 133) {
+		LOG(3, s, t, "Got IPv6 RS\n");
+		send_ipv6_ra(t, s, &ip);
+		return;
+	}
+
+	// Add on the tun header
+	p -= 4;
+	*(uint32_t *) p = htonl(PKTIPV6);
+	l += 4;
+
+	// Are we throttled and a slave?
+	if (session[s].tbf_in && !config->cluster_iam_master) {
+		// Pass it to the master for handling.
+		master_throttle_packet(session[s].tbf_in, p, l);
+		return;
+	}
+
+	// Are we throttled and a master??
+	if (session[s].tbf_in && config->cluster_iam_master) {
+		// Actually handle the throttled packets.
 		tbf_queue_packet(session[s].tbf_in, p, l);
 		return;
 	}
@@ -634,195 +1067,275 @@ void processipin(tunnelidt t, sessionidt s, u8 * p, u16 l)
 	// send to ethernet
 	if (tun_write(p, l) < 0)
 	{
-		STAT(tap_tx_errors);
-		log(0, 0, s, t, "Error writing %d bytes to TAP device: %s (tapfd=%d, p=%p)\n",
-			l, strerror(errno), tapfd, p);
+		STAT(tun_tx_errors);
+		LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
+			l, strerror(errno), tunfd, p);
+
+		return;
+	}
+
+	if (session[s].snoop_ip && session[s].snoop_port)
+	{
+		// Snooping this session
+		snoop_send_packet(p + 4, l - 4, session[s].snoop_ip, session[s].snoop_port);
 	}
 
+	session[s].cin += l - 4;
+	session[s].total_cin += l - 4;
+	sess_local[s].cin += l - 4;
+
+	session[s].pin++;
+	eth_tx += l - 4;
+
+	STAT(tun_tx_packets);
+	INC_STAT(tun_tx_bytes, l - 4);
 }
 
 //
 // Helper routine for the TBF filters.
 // Used to send queued data in from the user.
 //
-void send_ipin(sessionidt s, u8 *buf, int len)
+void send_ipin(sessionidt s, uint8_t *buf, int len)
 {
-	log_hex(5, "IP in throttled", buf, len);
-	if (write(tapfd, buf, len) < 0)
+	LOG_HEX(5, "IP in throttled", buf, len);
+
+	if (write(tunfd, buf, len) < 0)
 	{
-		STAT(tap_tx_errors);
-		log(0, 0, 0, 0, "Error writing %d bytes to TAP device: %s (tapfd=%d, p=%p)\n",
-			len, strerror(errno), tapfd, buf);
+		STAT(tun_tx_errors);
+		LOG(0, 0, 0, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
+			len, strerror(errno), tunfd, buf);
+
+		return;
+	}
+
+	if (session[s].snoop_ip && session[s].snoop_port)
+	{
+		// Snooping this session
+		snoop_send_packet(buf + 4, len - 4, session[s].snoop_ip, session[s].snoop_port);
 	}
 
 	// Increment packet counters
 	session[s].cin += len - 4;
 	session[s].total_cin += len - 4;
-	sess_count[s].cin += len - 4;
+	sess_local[s].cin += len - 4;
 
 	session[s].pin++;
 	eth_tx += len - 4;
+
+	STAT(tun_tx_packets);
+	INC_STAT(tun_tx_bytes, len - 4);
 }
 
 
-// Process LCP messages
-void processccp(tunnelidt t, sessionidt s, u8 * p, u16 l)
+// Process CCP messages
+void processccp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
 {
+	uint8_t b[MAXCONTROL];
+	uint8_t *q;
 
-	CSTAT(call_processccp);
+	CSTAT(processccp);
 
-	log_hex(5, "CCP", p, l);
-	if (l < 2 || (*p != ConfigReq && *p != TerminateReq))
-	{
-		log(1, 0, s, t, "Unexpecetd CCP request code %d\n", *p);
-		STAT(tunnel_rx_errors);
-		return ;
-	}
-	// reject
+	LOG_HEX(5, "CCP", p, l);
+	switch (l > 1 ? *p : 0)
 	{
-		u8 b[MAXCONTROL];
-		u8 *q;
-		if (*p == ConfigReq)
+	case ConfigAck:
+		session[s].flags |= SF_CCP_ACKED;
+		return;
+
+	case ConfigReq:
+		if (l < 6) // accept no compression
 		{
-			if (l < 6)
-			{
-				*p = ConfigAck;		// accept no compression
-			}
-			else
-			{
-				*p = ConfigRej;        // reject
-			}
+			*p = ConfigAck;
+			break;
 		}
+
+		// compression requested--reject
+		*p = ConfigRej;
+
+		// send CCP request for no compression for our end if not negotiated
+		if (!(session[s].flags & SF_CCP_ACKED))
+			initccp(t, s);
+
+		break;
+
+	case TerminateReq:
+	    	*p = TerminateAck;
+		break;
+
+	default:
+		if (l > 1)
+			LOG(1, s, t, "Unexpected CCP request code %d\n", *p);
 		else
-			*p = TerminateAck;     // close
-		q = makeppp(b, sizeof(b), p, l, t, s, PPPCCP);
-		if (!q) {
-			log(1,0,0,0, "Failed to send CCP packet.\n");	
-			return;
-		}
-		tunnelsend(b, l + (q - b), t); // send it
+			LOG(1, s, t, "Short CCP packet\n");
+
+		STAT(tunnel_rx_errors);
+		return;
 	}
+
+	if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPCCP)))
+		return;
+
+	tunnelsend(b, l + (q - b), t); // send it
 }
 
-// send a CHAP PP packet
+// send a CHAP challenge
 void sendchap(tunnelidt t, sessionidt s)
 {
-	u8 b[MAXCONTROL];
-	u16 r = session[s].radius;
-	u8 *q;
+	uint8_t b[MAXCONTROL];
+	uint16_t r = sess_local[s].radius;
+	uint8_t *q;
 
-	CSTAT(call_sendchap);
+	CSTAT(sendchap);
 
 	if (!r)
 	{
-		log(1, 0, s, t, "No RADIUS to send challenge\n");
+		LOG(1, s, t, "No RADIUS to send challenge\n");
 		STAT(tunnel_tx_errors);
-		return ;
-	}
-	log(1, 0, s, t, "Send CHAP challenge\n");
-	{                            // new challenge
-		int n;
-		for (n = 0; n < 15; n++)
-			radius[r].auth[n] = rand();
+		return;
 	}
-	radius[r].chap = 1;          // CHAP not PAP
+
+	LOG(1, s, t, "Send CHAP challenge\n");
+
+	radius[r].chap = 1;		// CHAP not PAP
 	radius[r].id++;
 	if (radius[r].state != RADIUSCHAP)
 		radius[r].try = 0;
+
 	radius[r].state = RADIUSCHAP;
 	radius[r].retry = backoff(radius[r].try++);
 	if (radius[r].try > 5)
 	{
-		sessionshutdown(s, "Timeout CHAP");
+		sessionshutdown(s, "CHAP timeout.", 3, 0);
 		STAT(tunnel_tx_errors);
 		return ;
 	}
 	q = makeppp(b, sizeof(b), 0, 0, t, s, PPPCHAP);
-	if (!q) {
-		log(1, 0, s, t, "failed to send CHAP challenge.\n");
-		return;
-	}
-	*q = 1;                      // challenhe
-	q[1] = radius[r].id;         // ID
-	q[4] = 16;                   // length
-	memcpy(q + 5, radius[r].auth, 16); // challenge
-	strcpy(q + 21, hostname);    // our name
-	*(u16 *) (q + 2) = htons(strlen(hostname) + 21); // length
+	if (!q) return;
+
+	*q = 1;					// challenge
+	q[1] = radius[r].id;			// ID
+	q[4] = 16;				// value size (size of challenge)
+	memcpy(q + 5, radius[r].auth, 16);	// challenge
+	strcpy(q + 21, hostname);		// our name
+	*(uint16_t *) (q + 2) = htons(strlen(hostname) + 21); // length
 	tunnelsend(b, strlen(hostname) + 21 + (q - b), t); // send it
 }
 
 // fill in a L2TP message with a PPP frame,
 // copies existing PPP message and changes magic number if seen
 // returns start of PPP frame
-u8 *makeppp(u8 * b, int size, u8 * p, int l, tunnelidt t, sessionidt s, u16 mtype)
+uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, tunnelidt t, sessionidt s, uint16_t mtype)
 {
+	if (size < 12) // Need more space than this!!
+	{
+		static int backtrace_count = 0;
+		LOG(0, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size);
+		log_backtrace(backtrace_count, 5)
+		return NULL;
+	}
 
-	if (size < 12)
-		return NULL;	// Need more space than this!!
-
-	*(u16 *) (b + 0) = htons(0x0002); // L2TP with no options
-	*(u16 *) (b + 2) = htons(tunnel[t].far); // tunnel
-	*(u16 *) (b + 4) = htons(session[s].far); // session
+	*(uint16_t *) (b + 0) = htons(0x0002); // L2TP with no options
+	*(uint16_t *) (b + 2) = htons(tunnel[t].far); // tunnel
+	*(uint16_t *) (b + 4) = htons(session[s].far); // session
 	b += 6;
-	if (mtype != PPPLCP && !(session[s].l2tp_flags & SESSIONACFC))
+	if (mtype == PPPLCP || !(session[s].l2tp_flags & SESSIONACFC))
 	{
-		*(u16 *) b = htons(0xFF03); // HDLC header
+		*(uint16_t *) b = htons(0xFF03); // HDLC header
 		b += 2;
 	}
 	if (mtype < 0x100 && session[s].l2tp_flags & SESSIONPFC)
 		*b++ = mtype;
 	else
 	{
-		*(u16 *) b = htons(mtype);
+		*(uint16_t *) b = htons(mtype);
 		b += 2;
 	}
 
-	if (l + 12 > size) {
-		log(3,0,0,0, "Would have overflowed the buffer in makeppp: size %d, len %d.\n", size, l);
-		return NULL;	// Run out of room to hold the packet!
+	if (l + 12 > size)
+	{
+		static int backtrace_count = 0;
+		LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%d)\n", size, l + 12);
+		log_backtrace(backtrace_count, 5)
+		return NULL;
 	}
+
 	if (p && l)
 		memcpy(b, p, l);
+
 	return b;
 }
 
-// find a PPP option, returns point to option, or 0 if not found
-u8 *findppp(u8 * b, u8 mtype)
+static uint8_t *add_lcp_auth(uint8_t *b, int size, int authtype)
 {
-	u16 l = ntohs(*(u16 *) (b + 2));
-	if (l < 4)
+	if ((authtype == AUTHCHAP && size < 5) || size < 4)
 		return 0;
-	b += 4;
-	l -= 4;
-	while (l)
+
+	*b++ = 3; // Authentication-Protocol
+	if (authtype == AUTHCHAP)
 	{
-		if (l < b[1] || !b[1])
-			return 0;            // faulty
-		if (*b == mtype)
-			return b;
-		l -= b[1];
-		b += b[1];
+		*b++ = 5; // length
+		*(uint16_t *) b = htons(PPPCHAP); b += 2;
+		*b++ = 5; // MD5
 	}
-	return 0;
+	else if (authtype == AUTHPAP)
+	{
+		*b++ = 4; // length
+		*(uint16_t *) b = htons(PPPPAP); b += 2;
+	}
+	else
+	{
+		LOG(0, 0, 0, "add_lcp_auth called with unsupported auth type %d\n", authtype);
+	}
+
+	return b;
 }
 
-// Send initial LCP ConfigReq
-void initlcp(tunnelidt t, sessionidt s)
+// Send initial LCP ConfigReq for MRU, authentication type and magic no
+void sendlcp(tunnelidt t, sessionidt s, int authtype)
 {
-	char b[500] = {0}, *q;
+	char b[500], *q, *l;
 
-	q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP);
-	if (!q) {
-		log(1, 0, s, t, "Failed to send LCP ConfigReq.\n");
+	if (!(q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP)))
 		return;
-	}
-	log(4, 0, s, t, "Sending LCP ConfigReq for PAP\n");
-	*q = ConfigReq;
-	*(u8 *)(q + 1) = (time_now % 255) + 1; // ID
-	*(u16 *)(q + 2) = htons(8); // Length
-	*(u8 *)(q + 4) = 3;
-	*(u8 *)(q + 5) = 4;
-	*(u16 *)(q + 6) = htons(0xC023); // PAP
-	tunnelsend(b, 12 + 8, t);
+
+	LOG(4, s, t, "Sending LCP ConfigReq for %s\n",
+	    config->radius_authprefer == AUTHCHAP ? "CHAP" : "PAP");
+
+	if (!session[s].mru)
+		session[s].mru = DEFAULT_MRU;
+
+	l = q;
+	*l++ = ConfigReq;
+	*l++ = (time_now % 255) + 1; // ID
+
+	*l++ = 1; *l++ = 4; // Maximum-Receive-Unit (length 4)
+	*(uint16_t *) l = htons(session[s].mru); l += 2;
+
+	l = add_lcp_auth(l, sizeof(b) - (l - b), authtype);
+
+	*l++ = 5; *l++ = 6; // Magic-Number (length 6)
+	*(uint32_t *) l = htonl(session[s].magic);
+	l += 4;
+
+	*(uint16_t *)(q + 2) = htons(l - q); // Length
+
+	LOG_HEX(5, "PPPLCP", q, l - q);
+	tunnelsend(b, (l - b), t);
 }
 
+// Send CCP request for no compression
+static void initccp(tunnelidt t, sessionidt s)
+{
+	char b[500], *q;
+
+	if (!(q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPCCP)))
+		return;
+
+	LOG(4, s, t, "Sending CCP ConfigReq for no compression\n");
+	*q = ConfigReq;
+	*(uint8_t *)(q + 1) = (time_now % 255) + 1; // ID
+	*(uint16_t *)(q + 2) = htons(4); // Length
+
+	LOG_HEX(5, "PPPCCP", q, 4);
+	tunnelsend(b, (q - b) + 4 , t);
+}