X-Git-Url: http://git.sameswireless.fr/l2tpns.git/blobdiff_plain/5d4d6bb059735067158e2a2ee1d500b6cb1af4dc..6d5c3ecb4d12ca63e4f9f809255691b3b2cda6e1:/l2tpns.c

diff --git a/l2tpns.c b/l2tpns.c
index a6bff01..88a62a5 100644
--- a/l2tpns.c
+++ b/l2tpns.c
@@ -4,7 +4,7 @@
 // Copyright (c) 2002 FireBrick (Andrews & Arnold Ltd / Watchfront Ltd) - GPL licenced
 // vim: sw=8 ts=8
 
-char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.50 2004-11-16 21:54:46 fred_nerk Exp $";
+char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.58 2004-11-28 02:53:11 bodea Exp $";
 
 #include <arpa/inet.h>
 #include <assert.h>
@@ -54,7 +54,7 @@ char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.50 2004-11-16 21:54:46 fred_nerk
 #endif /* BGP */
 
 // Globals
-struct configt *config = NULL;	// all configuration
+configt *config = NULL;		// all configuration
 int tunfd = -1;			// tun interface file handle. (network device)
 int udpfd = -1;			// UDP file handle
 int controlfd = -1;		// Control signal handle
@@ -88,9 +88,9 @@ linked_list *loaded_plugins;
 linked_list *plugins[MAX_PLUGIN_TYPES];
 
 #define membersize(STRUCT, MEMBER) sizeof(((STRUCT *)0)->MEMBER)
-#define CONFIG(NAME, MEMBER, TYPE) { NAME, offsetof(struct configt, MEMBER), membersize(struct configt, MEMBER), TYPE }
+#define CONFIG(NAME, MEMBER, TYPE) { NAME, offsetof(configt, MEMBER), membersize(configt, MEMBER), TYPE }
 
-struct config_descriptt config_values[] = {
+config_descriptt config_values[] = {
 	CONFIG("debug", debug, INT),
 	CONFIG("log_file", log_filename, STRING),
 	CONFIG("pid_file", pid_file, STRING),
@@ -146,6 +146,7 @@ sessiont *session = NULL;		// Array of session structures.
 sessioncountt *sess_count = NULL;	// Array of partial per-session traffic counters.
 radiust *radius = NULL;			// Array of radius structures.
 ippoolt *ip_address_pool = NULL;	// Array of dynamic IP addresses.
+ip_filtert *ip_filters = NULL;	// Array of named filters.
 static controlt *controlfree = 0;
 struct Tstats *_statistics = NULL;
 #ifdef RINGBUFFER
@@ -167,10 +168,10 @@ static void build_chap_response(char *challenge, u8 id, u16 challenge_length, ch
 static void update_config(void);
 static void read_config_file(void);
 static void initplugins(void);
-static void add_plugin(char *plugin_name);
-static void remove_plugin(char *plugin_name);
+static int add_plugin(char *plugin_name);
+static int remove_plugin(char *plugin_name);
 static void plugins_done(void);
-static void processcontrol(u8 * buf, int len, struct sockaddr_in *addr);
+static void processcontrol(u8 * buf, int len, struct sockaddr_in *addr, int alen);
 static tunnelidt new_tunnel(void);
 static int unhide_avp(u8 *avp, tunnelidt t, sessionidt s, u16 length);
 
@@ -434,8 +435,8 @@ static void initudp(void)
 	// Control
 	memset(&addr, 0, sizeof(addr));
 	addr.sin_family = AF_INET;
-	addr.sin_port = htons(1702);
-	controlfd = socket(AF_INET, SOCK_DGRAM, 17);
+	addr.sin_port = htons(NSCTL_PORT);
+	controlfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
 	setsockopt(controlfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
 	if (bind(controlfd, (void *) &addr, sizeof(addr)) < 0)
 	{
@@ -657,6 +658,7 @@ void tunnelsend(u8 * buf, u16 l, tunnelidt t)
 		STAT(tunnel_tx_errors);
 		return;
 	}
+
 	memset(&addr, 0, sizeof(addr));
 	addr.sin_family = AF_INET;
 	*(u32 *) & addr.sin_addr = htonl(tunnel[t].ip);
@@ -783,11 +785,7 @@ static void processipout(u8 * buf, int len)
 	// Add on L2TP header
 	{
 		u8 *p = makeppp(b, sizeof(b), buf, len, t, s, PPPIP);
-		if (!p)
-		{
-			LOG(3, session[s].ip, s, t, "failed to send packet in processipout.\n");
-			return;
-		}
+		if (!p) return;
 		tunnelsend(b, len + (p-b), t); // send it...
 	}
 
@@ -837,11 +835,7 @@ static void send_ipout(sessionidt s, u8 *buf, int len)
 	// Add on L2TP header
 	{
 		u8 *p = makeppp(b, sizeof(b),  buf, len, t, s, PPPIP);
-		if (!p)
-		{
-			LOG(3, session[s].ip, s, t, "failed to send packet in send_ipout.\n");
-			return;
-		}
+		if (!p) return;
 		tunnelsend(b, len + (p-b), t); // send it...
 	}
 
@@ -949,8 +943,10 @@ static void controladd(controlt * c, tunnelidt t, sessionidt s)
 		tunnel[t].controle->next = c;
 	else
 		tunnel[t].controls = c;
+
 	tunnel[t].controle = c;
 	tunnel[t].controlc++;
+
 	// send now if space in window
 	if (tunnel[t].controlc <= tunnel[t].window)
 	{
@@ -1006,6 +1002,44 @@ void throttle_session(sessionidt s, int rate_in, int rate_out)
 	}
 }
 
+// add/remove filters from session (-1 = no change)
+void filter_session(sessionidt s, int filter_in, int filter_out)
+{
+	if (!session[s].tunnel)
+		return; // No-one home.
+
+	if (!*session[s].user)
+	        return; // User not logged in
+
+	// paranoia
+	if (filter_in > MAXFILTER) filter_in = -1;
+	if (filter_out > MAXFILTER) filter_out = -1;
+	if (session[s].filter_in > MAXFILTER) session[s].filter_in = 0;
+	if (session[s].filter_out > MAXFILTER) session[s].filter_out = 0;
+
+	if (filter_in >= 0)
+	{
+		if (session[s].filter_in)
+			ip_filters[session[s].filter_in - 1].used--;
+
+		if (filter_in > 0)
+			ip_filters[filter_in - 1].used++;
+
+		session[s].filter_in = filter_in;
+	}
+
+	if (filter_out >= 0)
+	{
+		if (session[s].filter_out)
+			ip_filters[session[s].filter_out - 1].used--;
+
+		if (filter_out > 0)
+			ip_filters[filter_out - 1].used++;
+
+		session[s].filter_out = filter_out;
+	}
+}
+
 // start tidy shutdown of session
 void sessionshutdown(sessionidt s, char *reason)
 {
@@ -1052,15 +1086,20 @@ void sessionshutdown(sessionidt s, char *reason)
 	if (session[s].ip)
 	{                          // IP allocated, clear and unroute
 		int r;
+		int routed = 0;
 		for (r = 0; r < MAXROUTE && session[s].route[r].ip; r++)
 		{
+			if ((session[s].ip & session[s].route[r].mask) ==
+			    (session[s].route[r].ip & session[s].route[r].mask))
+				routed++;
+
 			routeset(s, session[s].route[r].ip, session[s].route[r].mask, 0, 0);
 			session[s].route[r].ip = 0;
 		}
 
 		if (session[s].ip_pool_index == -1) // static ip
 		{
-			routeset(s, session[s].ip, 0, 0, 0);	// Delete route.
+			if (!routed) routeset(s, session[s].ip, 0, 0, 0);
 			session[s].ip = 0;
 		}
 		else
@@ -1080,6 +1119,10 @@ void sessionshutdown(sessionidt s, char *reason)
 	if (!session[s].die)
 		session[s].die = now() + 150; // Clean up in 15 seconds
 
+	// update filter refcounts
+	if (session[s].filter_in) ip_filters[session[s].filter_in - 1].used--;
+	if (session[s].filter_out) ip_filters[session[s].filter_out - 1].used--;
+
 	cluster_send_session(s);
 }
 
@@ -1109,11 +1152,7 @@ void sendipcp(tunnelidt t, sessionidt s)
 	}
 
 	q = makeppp(buf,sizeof(buf), 0, 0, t, s, PPPIPCP);
-	if (!q)
-	{
-		LOG(3, session[s].ip, s, t, "failed to send packet in sendipcp.\n");
-		return;
-	}
+	if (!q) return;
 
 	*q = ConfigReq;
 	q[1] = r << RADIUS_SHIFT;                    // ID, dont care, we only send one type of request
@@ -1312,10 +1351,9 @@ void processudp(u8 * buf, int len, struct sockaddr_in *addr)
 			STAT(tunnel_rx_errors);
 			return;
 		}
-		LOG(3, ntohl(addr->sin_addr.s_addr), s, t, "Control message (%d bytes): (unacked %d) l-ns %d l-nr %d r-ns %d r-nr %d\n",
-				l, tunnel[t].controlc, tunnel[t].ns, tunnel[t].nr, ns, nr);
-		// if no tunnel specified, assign one
-		if (!t)
+
+		// check for duplicate tunnel open message
+		if (!t && ns == 0)
 		{
 			int i;
 
@@ -1329,10 +1367,15 @@ void processudp(u8 * buf, int len, struct sockaddr_in *addr)
 					tunnel[i].port != ntohs(addr->sin_port) )
 					continue;
 				t = i;
+				LOG(3, ntohl(addr->sin_addr.s_addr), s, t, "Duplicate SCCRQ?\n");
 				break;
 			}
 		}
 
+		LOG(3, ntohl(addr->sin_addr.s_addr), s, t, "Control message (%d bytes): (unacked %d) l-ns %d l-nr %d r-ns %d r-nr %d\n",
+				l, tunnel[t].controlc, tunnel[t].ns, tunnel[t].nr, ns, nr);
+
+		// if no tunnel specified, assign one
 		if (!t)
 		{
 			if (!(t = new_tunnel()))
@@ -1345,8 +1388,28 @@ void processudp(u8 * buf, int len, struct sockaddr_in *addr)
 			tunnel[t].ip = ntohl(*(ipt *) & addr->sin_addr);
 			tunnel[t].port = ntohs(addr->sin_port);
 			tunnel[t].window = 4; // default window
-			LOG(1, ntohl(addr->sin_addr.s_addr), 0, t, "   New tunnel from %u.%u.%u.%u/%u ID %d\n", tunnel[t].ip >> 24, tunnel[t].ip >> 16 & 255, tunnel[t].ip >> 8 & 255, tunnel[t].ip & 255, tunnel[t].port, t);
 			STAT(tunnel_created);
+			LOG(1, ntohl(addr->sin_addr.s_addr), 0, t, "   New tunnel from %u.%u.%u.%u/%u ID %d\n",
+				tunnel[t].ip >> 24, tunnel[t].ip >> 16 & 255,
+				tunnel[t].ip >> 8 & 255, tunnel[t].ip & 255, tunnel[t].port, t);
+		}
+
+			// If the 'ns' just received is not the 'nr' we're
+			// expecting, just send an ack and drop it.
+			//
+			// if 'ns' is less, then we got a retransmitted packet.
+			// if 'ns' is greater than missed a packet. Either way
+			// we should ignore it.
+		if (ns != tunnel[t].nr)
+		{
+			// is this the sequence we were expecting?
+			STAT(tunnel_rx_errors);
+			LOG(1, ntohl(addr->sin_addr.s_addr), 0, t, "   Out of sequence tunnel %d, (%d is not the expected %d)\n",
+				t, ns, tunnel[t].nr);
+
+			if (l)	// Is this not a ZLB?
+				controlnull(t);
+			return;
 		}
 
 		// This is used to time out old tunnels
@@ -1356,7 +1419,7 @@ void processudp(u8 * buf, int len, struct sockaddr_in *addr)
 		{
 			int skip = tunnel[t].window; // track how many in-window packets are still in queue
 				// some to clear maybe?
-			while (tunnel[t].controlc && (((tunnel[t].ns - tunnel[t].controlc) - nr) & 0x8000))
+			while (tunnel[t].controlc > 0 && (((tunnel[t].ns - tunnel[t].controlc) - nr) & 0x8000))
 			{
 				controlt *c = tunnel[t].controls;
 				tunnel[t].controls = c->next;
@@ -1367,22 +1430,6 @@ void processudp(u8 * buf, int len, struct sockaddr_in *addr)
 				tunnel[t].try = 0; // we have progress
 			}
 
-				// If the 'ns' just received is not the 'nr' we're
-				// expecting, just send an ack and drop it.
-				//
-				// if 'ns' is less, then we got a retransmitted packet.
-				// if 'ns' is greater than missed a packet. Either way
-				// we should ignore it.
-			if (ns != tunnel[t].nr)
-			{
-				// is this the sequence we were expecting?
-				LOG(1, ntohl(addr->sin_addr.s_addr), 0, t, "   Out of sequence tunnel %d, (%d is not the expected %d)\n", t, ns, tunnel[t].nr);
-				STAT(tunnel_rx_errors);
-
-				if (l)	// Is this not a ZLB?
-					controlnull(t);
-				return;
-			}
 			// receiver advance (do here so quoted correctly in any sends below)
 			if (l) tunnel[t].nr = (ns + 1);
 			if (skip < 0) skip = 0;
@@ -2067,11 +2114,7 @@ static int regular_cleanups(void)
 			u8 b[MAXCONTROL] = {0};
 
 			u8 *q = makeppp(b, sizeof(b), 0, 0, session[s].tunnel, s, PPPLCP);
-			if (!q)
-			{
-				LOG(3, session[s].ip, s, t, "failed to send ECHO packet.\n");
-				continue;
-			}
+			if (!q) continue;
 
 			*q = EchoReq;
 			*(u8 *)(q + 1) = (time_now % 255); // ID
@@ -2130,6 +2173,22 @@ static int regular_cleanups(void)
 				send++;
 			}
 
+			if (a & CLI_SESS_NOFILTER)
+			{
+				LOG(2, 0, s, session[s].tunnel, "Un-filtering session by CLI\n");
+				filter_session(s, 0, 0);
+				send++;
+			}
+			else if (a & CLI_SESS_FILTER)
+			{
+				LOG(2, 0, s, session[s].tunnel, "Filtering session by CLI (in=%d, out=%d)\n",
+				    cli_session_actions[s].filter_in,
+				    cli_session_actions[s].filter_out);
+
+				filter_session(s, cli_session_actions[s].filter_in, cli_session_actions[s].filter_out);
+				send++;
+			}
+
 			if (send)
 				cluster_send_session(s);
 
@@ -2324,7 +2383,7 @@ static void mainloop(void)
 			}
 
 			if (FD_ISSET(controlfd, &r))
-				processcontrol(buf, recvfrom(controlfd, buf, sizeof(buf), MSG_WAITALL, (void *) &addr, &alen), &addr);
+				processcontrol(buf, recvfrom(controlfd, buf, sizeof(buf), MSG_WAITALL, (void *) &addr, &alen), &addr, alen);
 
 			if (FD_ISSET(clifd, &r))
 			{
@@ -2490,12 +2549,12 @@ static void initdata(int optdebug, char *optconfig)
 		LOG(0, 0, 0, 0, "Error doing malloc for _statistics: %s\n", strerror(errno));
 		exit(1);
 	}
-	if (!(config = shared_malloc(sizeof(struct configt))))
+	if (!(config = shared_malloc(sizeof(configt))))
 	{
 		LOG(0, 0, 0, 0, "Error doing malloc for configuration: %s\n", strerror(errno));
 		exit(1);
 	}
-	memset(config, 0, sizeof(struct configt));
+	memset(config, 0, sizeof(configt));
 	time(&config->start_time);
 	strncpy(config->config_file, optconfig, strlen(optconfig));
 	config->debug = optdebug;
@@ -2531,6 +2590,13 @@ static void initdata(int optdebug, char *optconfig)
 		exit(1);
 	}
 
+if (!(ip_filters = shared_malloc(sizeof(ip_filtert) * MAXFILTER)))
+{
+	LOG(0, 0, 0, 0, "Error doing malloc for ip_filters: %s\n", strerror(errno));
+	exit(1);
+}
+memset(ip_filters, 0, sizeof(ip_filtert) * MAXFILTER);
+
 #ifdef RINGBUFFER
 	if (!(ringbuffer = shared_malloc(sizeof(struct Tringbuffer))))
 	{
@@ -2582,11 +2648,11 @@ static void initdata(int optdebug, char *optconfig)
 	_statistics->start_time = _statistics->last_reset = time(NULL);
 
 #ifdef BGP
- 	if (!(bgp_peers = shared_malloc(sizeof(struct bgp_peer) * BGP_NUM_PEERS)))
- 	{
- 		LOG(0, 0, 0, 0, "Error doing malloc for bgp: %s\n", strerror(errno));
- 		exit(1);
- 	}
+	if (!(bgp_peers = shared_malloc(sizeof(struct bgp_peer) * BGP_NUM_PEERS)))
+	{
+		LOG(0, 0, 0, 0, "Error doing malloc for bgp: %s\n", strerror(errno));
+		exit(1);
+	}
 #endif /* BGP */
 }
 
@@ -2934,31 +3000,31 @@ int main(int argc, char *argv[])
 	{
 		switch (i)
 		{
-			case 'd':
-				if (fork()) exit(0);
-				setsid();
-				freopen("/dev/null", "r", stdin);
-				freopen("/dev/null", "w", stdout);
-				freopen("/dev/null", "w", stderr);
-				break;
-			case 'v':
-				optdebug++;
-				break;
-			case 'c':
-			    	optconfig = optarg;
-				break;
-			case 'h':
-				snprintf(hostname, sizeof(hostname), "%s", optarg);
-				break;
-			default:
-				printf("Args are:\n"
-				       "\t-d\t\tDetach from terminal\n"
-				       "\t-c <file>\tConfig file\n"
-				       "\t-h <hostname>\tForce hostname\n"
-				       "\t-v\t\tDebug\n");
-
-				return (0);
-				break;
+		case 'd':
+			if (fork()) exit(0);
+			setsid();
+			freopen("/dev/null", "r", stdin);
+			freopen("/dev/null", "w", stdout);
+			freopen("/dev/null", "w", stderr);
+			break;
+		case 'v':
+			optdebug++;
+			break;
+		case 'c':
+			optconfig = optarg;
+			break;
+		case 'h':
+			snprintf(hostname, sizeof(hostname), "%s", optarg);
+			break;
+		default:
+			printf("Args are:\n"
+			       "\t-d\t\tDetach from terminal\n"
+			       "\t-c <file>\tConfig file\n"
+			       "\t-h <hostname>\tForce hostname\n"
+			       "\t-v\t\tDebug\n");
+
+			return (0);
+			break;
 		}
 	}
 
@@ -3576,18 +3642,30 @@ int sessionsetup(tunnelidt t, sessionidt s)
 		}
 	}
 
+	{
+	    	int routed = 0;
+
 		// Add the route for this session.
-		//
-		// Static IPs need to be routed. Anything else
-		// is part of the IP address pool and is already routed,
-		// it just needs to be added to the IP cache.
-	if (session[s].ip_pool_index == -1) // static ip
-		routeset(s, session[s].ip, 0, 0, 1);
-	else
-		cache_ipmap(session[s].ip, s);
+		for (r = 0; r < MAXROUTE && session[s].route[r].ip; r++)
+		{
+			if ((session[s].ip & session[s].route[r].mask) ==
+			    (session[s].route[r].ip & session[s].route[r].mask))
+				routed++;
 
-	for (r = 0; r < MAXROUTE && session[s].route[r].ip; r++)
-		routeset(s, session[s].route[r].ip, session[s].route[r].mask, 0, 1);
+			routeset(s, session[s].route[r].ip, session[s].route[r].mask, 0, 1);
+		}
+
+		// Static IPs need to be routed if not already
+		// convered by a Framed-Route.  Anything else is part
+		// of the IP address pool and is already routed, it
+		// just needs to be added to the IP cache.
+		if (session[s].ip_pool_index == -1) // static ip
+		{
+			if (!routed) routeset(s, session[s].ip, 0, 0, 1);
+		}
+		else
+			cache_ipmap(session[s].ip, s);
+	}
 
 	if (!session[s].unique_id)
 	{
@@ -3631,6 +3709,7 @@ int sessionsetup(tunnelidt t, sessionidt s)
 int load_session(sessionidt s, sessiont *new)
 {
 	int i;
+	int newip = 0;
 
 		// Sanity checks.
 	if (new->ip_pool_index >= MAXIPPOOL ||
@@ -3648,46 +3727,89 @@ int load_session(sessionidt s, sessiont *new)
 
 	session[s].tunnel = new->tunnel; // For logging in cache_ipmap
 
+	// See if routes/ip cache need updating
+	if (new->ip != session[s].ip)
+		newip++;
 
-	if (new->ip != session[s].ip)	// Changed ip. fix up hash tables.
+	for (i = 0; !newip && i < MAXROUTE && (session[s].route[i].ip || new->route[i].ip); i++)
+		if (new->route[i].ip != session[s].route[i].ip ||
+		    new->route[i].mask != session[s].route[i].mask)
+			newip++;
+
+	// needs update
+	if (newip)
 	{
-		if (session[s].ip)	// If there's an old one, remove it.
+	    	int routed = 0;
+
+		// remove old routes...
+		for (i = 0; i < MAXROUTE && session[s].route[i].ip; i++)
 		{
-			// Remove any routes if the IP has changed
-			for (i = 0; i < MAXROUTE && session[s].route[i].ip; i++)
-			{
-				routeset(s, session[s].route[i].ip, session[s].route[i].mask, 0, 0);
-				session[s].route[i].ip = 0;
-			}
+			if ((session[s].ip & session[s].route[i].mask) ==
+			    (session[s].route[i].ip & session[s].route[i].mask))
+				routed++;
+
+			routeset(s, session[s].route[i].ip, session[s].route[i].mask, 0, 0);
+		}
 
+		// ...ip
+		if (session[s].ip)
+		{
 			if (session[s].ip_pool_index == -1) // static IP
-				routeset(s, session[s].ip, 0, 0, 0);
+			{
+				if (!routed) routeset(s, session[s].ip, 0, 0, 0);
+			}
 			else		// It's part of the IP pool, remove it manually.
 				uncache_ipmap(session[s].ip);
 		}
 
+		routed = 0;
+
+		// add new routes...
+		for (i = 0; i < MAXROUTE && new->route[i].ip; i++)
+		{
+			if ((new->ip & new->route[i].mask) ==
+			    (new->route[i].ip & new->route[i].mask))
+				routed++;
+
+			routeset(s, new->route[i].ip, new->route[i].mask, 0, 1);
+		}
+
+		// ...ip
 		if (new->ip)
 		{
 			// If there's a new one, add it.
 			if (new->ip_pool_index == -1)
-				routeset(s, new->ip, 0, 0, 1);
+			{
+				if (!routed) routeset(s, new->ip, 0, 0, 1);
+			}
 			else
 				cache_ipmap(new->ip, s);
 		}
 	}
 
-	// Update routed networks
-	for (i = 0; i < MAXROUTE && (session[s].route[i].ip || new->route[i].ip); i++)
+	// check filters
+	if (new->filter_in && (new->filter_in > MAXFILTER || !ip_filters[new->filter_in - 1].name[0]))
 	{
-		if (new->route[i].ip == session[s].route[i].ip &&
-		    new->route[i].mask == session[s].route[i].mask)
-			continue;
+		LOG(2, session[s].ip, s, session[s].tunnel, "Dropping invalid input filter %d\n", (int) new->filter_in);
+		new->filter_in = 0;
+	}
 
-		if (session[s].route[i].ip) // Remove the old one if it exists.
-			routeset(s, session[s].route[i].ip, session[s].route[i].mask, 0, 0);
+	if (new->filter_out && (new->filter_out > MAXFILTER || !ip_filters[new->filter_out - 1].name[0]))
+	{
+		LOG(2, session[s].ip, s, session[s].tunnel, "Dropping invalid output filter %d\n", (int) new->filter_out);
+		new->filter_out = 0;
+	}
 
-		if (new->route[i].ip)	// Add the new one if it exists.
-			routeset(s, new->route[i].ip, new->route[i].mask, 0, 1);
+	if (new->filter_in != session[s].filter_in)
+	{
+		if (session[s].filter_in) ip_filters[session[s].filter_in - 1].used--;
+		if (new->filter_in)       ip_filters[new->filter_in - 1].used++;
+	}
+
+	if (new->filter_out != session[s].filter_out)
+	{
+		if (session[s].filter_out) ip_filters[session[s].filter_out - 1].used--;
+		if (new->filter_out)       ip_filters[new->filter_out - 1].used++;
 	}
 
 	if (new->tunnel && s > config->cluster_highest_sessionid)	// Maintain this in the slave. It's used
@@ -3751,7 +3873,7 @@ static void *getconfig(char *key, enum config_typet type)
 	return 0;
 }
 
-static void add_plugin(char *plugin_name)
+static int add_plugin(char *plugin_name)
 {
 	static struct pluginfuncs funcs = {
 		_log,
@@ -3760,10 +3882,12 @@ static void add_plugin(char *plugin_name)
 		sessionbyuser,
 		sessiontbysessionidt,
 		sessionidtbysessiont,
-		sessionkill,
 		radiusnew,
 		radiussend,
 		getconfig,
+		sessionkill,
+		throttle_session,
+		cluster_send_session,
 	};
 
 	void *p = open_plugin(plugin_name, 1);
@@ -3773,22 +3897,22 @@ static void add_plugin(char *plugin_name)
 	if (!p)
 	{
 		LOG(1, 0, 0, 0, "   Plugin load failed: %s\n", dlerror());
-		return;
+		return -1;
 	}
 
 	if (ll_contains(loaded_plugins, p))
 	{
 		dlclose(p);
-		return;
+		return 0; // already loaded
 	}
 
 	{
-		int *v = dlsym(p, "__plugin_api_version");
+		int *v = dlsym(p, "plugin_api_version");
 		if (!v || *v != PLUGIN_API_VERSION)
 		{
 			LOG(1, 0, 0, 0, "   Plugin load failed: API version mismatch: %s\n", dlerror());
 			dlclose(p);
-			return;
+			return -1;
 		}
 	}
 
@@ -3798,7 +3922,7 @@ static void add_plugin(char *plugin_name)
 		{
 			LOG(1, 0, 0, 0, "   Plugin load failed: plugin_init() returned FALSE: %s\n", dlerror());
 			dlclose(p);
-			return;
+			return -1;
 		}
 	}
 
@@ -3815,6 +3939,7 @@ static void add_plugin(char *plugin_name)
 	}
 
 	LOG(2, 0, 0, 0, "   Loaded plugin %s\n", plugin_name);
+	return 1;
 }
 
 static void run_plugin_done(void *plugin)
@@ -3825,45 +3950,51 @@ static void run_plugin_done(void *plugin)
 		donefunc();
 }
 
-static void remove_plugin(char *plugin_name)
+static int remove_plugin(char *plugin_name)
 {
 	void *p = open_plugin(plugin_name, 0);
-	int i;
+	int loaded = 0;
 
 	if (!p)
-		return;
-
-	for (i = 0; i < max_plugin_functions; i++)
-	{
-		void *x;
-		if (plugin_functions[i] && (x = dlsym(p, plugin_functions[i])))
-			ll_delete(plugins[i], x);
-	}
+		return -1;
 
 	if (ll_contains(loaded_plugins, p))
 	{
+		int i;
+		for (i = 0; i < max_plugin_functions; i++)
+		{
+			void *x;
+			if (plugin_functions[i] && (x = dlsym(p, plugin_functions[i])))
+				ll_delete(plugins[i], x);
+		}
+
 		ll_delete(loaded_plugins, p);
 		run_plugin_done(p);
+		loaded = 1;
 	}
 
 	dlclose(p);
 	LOG(2, 0, 0, 0, "Removed plugin %s\n", plugin_name);
+	return loaded;
 }
 
 int run_plugins(int plugin_type, void *data)
 {
 	int (*func)(void *data);
-	if (!plugins[plugin_type] || plugin_type > max_plugin_functions) return 1;
+
+	if (!plugins[plugin_type] || plugin_type > max_plugin_functions)
+		return PLUGIN_RET_ERROR;
 
 	ll_reset(plugins[plugin_type]);
 	while ((func = ll_next(plugins[plugin_type])))
 	{
-		int rc;
-		rc = func(data);
-		if (rc == PLUGIN_RET_STOP) return 1;
-		if (rc == PLUGIN_RET_ERROR) return 0;
+		int r = func(data);
+
+		if (r != PLUGIN_RET_OK)
+			return r; // stop here
 	}
-	return 1;
+
+	return PLUGIN_RET_OK;
 }
 
 static void plugins_done()
@@ -3875,39 +4006,174 @@ static void plugins_done()
 		run_plugin_done(p);
 }
 
-static void processcontrol(u8 * buf, int len, struct sockaddr_in *addr)
+static void processcontrol(u8 * buf, int len, struct sockaddr_in *addr, int alen)
 {
-	char *resp;
-	int l;
-	struct param_control param = { buf, len, ntohl(addr->sin_addr.s_addr), ntohs(addr->sin_port), NULL, 0, 0 };
-
+	struct nsctl request;
+	struct nsctl response;
+	int type = unpack_control(&request, buf, len);
+	int r;
+	void *p;
 
 	if (log_stream && config->debug >= 4)
 	{
-		LOG(4, ntohl(addr->sin_addr.s_addr), 0, 0, "Received ");
-		dump_packet(buf, log_stream);
+		if (type < 0)
+		{
+			LOG(4, ntohl(addr->sin_addr.s_addr), 0, 0, "Bogus control message (%d)\n", type);
+		}
+		else
+		{
+			LOG(4, ntohl(addr->sin_addr.s_addr), 0, 0, "Received ");
+			dump_control(&request, log_stream);
+		}
 	}
 
-	resp = calloc(1400, 1);
-	l = new_packet(PKT_RESP_ERROR, resp);
-	*(int *)(resp + 6) = *(int *)(buf + 6);
+	switch (type)
+	{
+	case NSCTL_REQ_LOAD:
+		if (request.argc != 1)
+		{
+			response.type = NSCTL_RES_ERR;
+			response.argc = 1;
+			response.argv[0] = "name of plugin required";
+		}
+		else if ((r = add_plugin(request.argv[0])) < 1)
+		{
+			response.type = NSCTL_RES_ERR;
+			response.argc = 1;
+			response.argv[0] = !r
+				? "plugin already loaded"
+				: "error loading plugin";
+		}
+		else
+		{
+			response.type = NSCTL_RES_OK;
+			response.argc = 0;
+		}
+
+		break;
+
+	case NSCTL_REQ_UNLOAD:
+		if (request.argc != 1)
+		{
+			response.type = NSCTL_RES_ERR;
+			response.argc = 1;
+			response.argv[0] = "name of plugin required";
+		}
+		else if ((r = remove_plugin(request.argv[0])) < 1)
+		{
+			response.type = NSCTL_RES_ERR;
+			response.argc = 1;
+			response.argv[0] = !r
+				? "plugin not loaded"
+				: "plugin not found";
+		}
+		else
+		{
+			response.type = NSCTL_RES_OK;
+			response.argc = 0;
+		}
+
+		break;
+
+	case NSCTL_REQ_HELP:
+		response.type = NSCTL_RES_OK;
+		response.argc = 0;
+
+		ll_reset(loaded_plugins);
+		while ((p = ll_next(loaded_plugins)))
+		{
+			char **help = dlsym(p, "plugin_control_help");
+			while (response.argc < 0xff && help && *help)
+				response.argv[response.argc++] = *help++;
+		}
 
-	param.type = ntohs(*(short *)(buf + 2));
-	param.id = ntohl(*(int *)(buf + 6));
-	param.data_length = ntohs(*(short *)(buf + 4)) - 10;
-	param.data = (param.data_length > 0) ? (char *)(buf + 10) : NULL;
-	param.response = resp;
-	param.response_length = l;
+		break;
 
-	run_plugins(PLUGIN_CONTROL, &param);
+	case NSCTL_REQ_CONTROL:
+		{
+			struct param_control param = {
+				config->cluster_iam_master,
+				request.argc,
+				request.argv,
+				0,
+				NULL,
+			};
+
+			int r = run_plugins(PLUGIN_CONTROL, &param);
+
+			if (r == PLUGIN_RET_ERROR)
+			{
+				response.type = NSCTL_RES_ERR;
+				response.argc = 1;
+				response.argv[0] = param.additional
+					? param.additional
+					: "error returned by plugin";
+			}
+			else if (r == PLUGIN_RET_NOTMASTER)
+			{
+				static char msg[] = "must be run on master: 000.000.000.000";
 
-	if (param.send_response)
+				response.type = NSCTL_RES_ERR;
+				response.argc = 1;
+				if (config->cluster_master_address)
+				{
+					strcpy(msg + 23, inet_toa(config->cluster_master_address));
+					response.argv[0] = msg;
+				}
+				else
+				{
+				    	response.argv[0] = "must be run on master: none elected";
+				}
+			}
+			else if (!(param.response & NSCTL_RESPONSE))
+			{
+				response.type = NSCTL_RES_ERR;
+				response.argc = 1;
+				response.argv[0] = param.response
+					? "unrecognised response value from plugin"
+					: "unhandled action";
+			}
+			else
+			{
+				response.type = param.response;
+				response.argc = 0;
+				if (param.additional)
+				{
+					response.argc = 1;
+					response.argv[0] = param.additional;
+				}
+			}
+		}
+
+		break;
+
+	default:
+		response.type = NSCTL_RES_ERR;
+		response.argc = 1;
+		response.argv[0] = "error unpacking control packet";
+	}
+
+	buf = calloc(NSCTL_MAX_PKT_SZ, 1);
+	if (!buf)
+	{
+		LOG(2, ntohl(addr->sin_addr.s_addr), 0, 0, "Failed to allocate nsctl response\n");
+		return;
+	}
+
+	r = pack_control(buf, NSCTL_MAX_PKT_SZ, response.type, response.argc, response.argv);
+	if (r > 0)
 	{
-		send_packet(controlfd, ntohl(addr->sin_addr.s_addr), ntohs(addr->sin_port), param.response, param.response_length);
-		LOG(4, ntohl(addr->sin_addr.s_addr), 0, 0, "Sent Control packet response\n");
+		sendto(controlfd, buf, r, 0, (const struct sockaddr *) addr, alen);
+		if (log_stream && config->debug >= 4)
+		{
+			LOG(4, ntohl(addr->sin_addr.s_addr), 0, 0, "Sent ");
+			dump_control(&response, log_stream);
+		}
 	}
+	else
+		LOG(2, ntohl(addr->sin_addr.s_addr), 0, 0, "Failed to pack nsctl response (%d)\n", r);
 
-	free(resp);
+	free(buf);
 }
 
 static tunnelidt new_tunnel()