X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=secnet.git;a=blobdiff_plain;f=netlink.c;h=b6650eb36f55ccd58910cb6e7203feae5e44fe93;hp=886ce058cd6099c4a9d3a2bc7af16f6b9a5bde9e;hb=d3fe100dfc120244d316e083ce87b1eb130fe4fd;hpb=9d3a4132788b198345116624761c12ed7bc936b6

diff --git a/netlink.c b/netlink.c
index 886ce05..b6650eb 100644
--- a/netlink.c
+++ b/netlink.c
@@ -10,7 +10,12 @@
 
 #include "secnet.h"
 #include "util.h"
+#include "ipaddr.h"
 #include "netlink.h"
+#include "process.h"
+
+#define OPT_SOFTROUTE   1
+#define OPT_ALLOWROUTE  2
 
 /* Generic IP checksum routine */
 static inline uint16_t ip_csum(uint8_t *iph,uint32_t count)
@@ -175,11 +180,19 @@ static void netlink_icmp_csum(struct icmphdr *h)
 static bool_t netlink_icmp_may_reply(struct buffer_if *buf)
 {
     struct iphdr *iph;
+    struct icmphdr *icmph;
     uint32_t source;
 
     iph=(struct iphdr *)buf->start;
-    if (iph->protocol==1) return False; /* Overly-broad; we may reply to
-					   eg. icmp echo-request */
+    icmph=(struct icmphdr *)buf->start;
+    if (iph->protocol==1) {
+	switch(icmph->type) {
+	case 3: /* Destination unreachable */
+	case 11: /* Time Exceeded */
+	case 12: /* Parameter Problem */
+	    return False;
+	}
+    }
     /* How do we spot broadcast destination addresses? */
     if (ntohs(iph->frag_off)&0x1fff) return False; /* Non-initial fragment */
     source=ntohl(iph->saddr);
@@ -252,9 +265,9 @@ static bool_t netlink_check(struct netlink *st, struct buffer_if *buf)
     return True;
 }
 
-/* Deliver a packet. "client" points to the _origin_ of the packet, not
-   its destination. (May be used when sending ICMP response - avoid
-   asymmetric routing.) */
+/* Deliver a packet. "client" is the _origin_ of the packet, not its
+   destination, and is NULL for packets from the host and packets
+   generated internally in secnet.  */
 static void netlink_packet_deliver(struct netlink *st,
 				   struct netlink_client *client,
 				   struct buffer_if *buf)
@@ -263,75 +276,107 @@ static void netlink_packet_deliver(struct netlink *st,
     uint32_t dest=ntohl(iph->daddr);
     uint32_t source=ntohl(iph->saddr);
     uint32_t best_quality;
+    bool_t allow_route=False;
+    bool_t found_allowed=False;
     int best_match;
     int i;
 
     BUF_ASSERT_USED(buf);
 
     if (dest==st->secnet_address) {
-	Message(M_ERROR,"%s: trying to deliver a packet to myself!\n");
+	Message(M_ERR,"%s: trying to deliver a packet to myself!\n");
 	BUF_FREE(buf);
 	return;
     }
     
-    if (!client) {
-	/* Origin of packet is host or secnet. Might be for a tunnel. */
-	best_quality=0;
-	best_match=-1;
-	for (i=0; i<st->n_routes; i++) {
-	    if (st->routes[i].up && subnet_match(&st->routes[i].net,dest)) {
-		if (st->routes[i].c->link_quality>best_quality
-		    || best_quality==0) {
-		    best_quality=st->routes[i].c->link_quality;
-		    best_match=i;
-		    /* If quality isn't perfect we may wish to
-		       consider kicking the tunnel with a 0-length
-		       packet to prompt it to perform a key setup.
-		       Then it'll eventually decide it's up or
-		       down. */
-		    /* If quality is perfect we don't need to search
-                       any more. */
-		    if (best_quality>=MAXIMUM_LINK_QUALITY) break;
-		}
-	    }
-	}
-	if (best_match==-1) {
-	    /* Not going down a tunnel. Might be for the host. 
-	       XXX think about this - only situation should be if we're
-	       sending ICMP. */
-	    if (source!=st->secnet_address) {
-		Message(M_ERROR,"netlink_packet_deliver: outgoing packet "
-			"from host that won't fit down any of our tunnels!\n");
-		/* XXX I think this could also occur if a soft tunnel just
-		   went down, but still had packets queued in the kernel. */
-		BUF_FREE(buf);
-	    } else {
-		st->deliver_to_host(st->dst,NULL,buf);
-		BUF_ASSERT_FREE(buf);
+    /* Packets from the host (client==NULL) may always be routed.  Packets
+       from clients with the allow_route option will also be routed. */
+    if (!client || (client && (client->options & OPT_ALLOWROUTE)))
+	allow_route=True;
+
+    /* If !allow_route, we check the routing table anyway, and if
+       there's a suitable route with OPT_ALLOWROUTE set we use it.  If
+       there's a suitable route, but none with OPT_ALLOWROUTE set then
+       we generate ICMP 'communication with destination network
+       administratively prohibited'. */
+
+    best_quality=0;
+    best_match=-1;
+    for (i=0; i<st->n_clients; i++) {
+	if (st->routes[i]->up &&
+	    ipset_contains_addr(st->routes[i]->networks,dest)) {
+	    /* It's an available route to the correct destination. But is
+	       it better than the one we already have? */
+
+	    /* If we have already found an allowed route then we don't
+	       bother looking at routes we're not allowed to use.  If
+	       we don't yet have an allowed route we'll consider any.  */
+	    if (!allow_route && found_allowed) {
+		if (!(st->routes[i]->options&OPT_ALLOWROUTE)) continue;
 	    }
-	} else {
-	    if (best_quality>0) {
-		st->routes[best_match].c->deliver(
-		    st->routes[best_match].c->dst,
-		    st->routes[best_match].c, buf);
-		BUF_ASSERT_FREE(buf);
-	    } else {
-		/* Generate ICMP destination unreachable */
-		netlink_icmp_simple(st,buf,client,3,0); /* client==NULL */
-		BUF_FREE(buf);
+	    
+	    if (st->routes[i]->link_quality>best_quality
+		|| best_quality==0) {
+		best_quality=st->routes[i]->link_quality;
+		best_match=i;
+		if (st->routes[i]->options&OPT_ALLOWROUTE)
+		    found_allowed=True;
+		/* If quality isn't perfect we may wish to
+		   consider kicking the tunnel with a 0-length
+		   packet to prompt it to perform a key setup.
+		   Then it'll eventually decide it's up or
+		   down. */
+		/* If quality is perfect and we're allowed to use the
+		   route we don't need to search any more. */
+		if (best_quality>=MAXIMUM_LINK_QUALITY && 
+		    (allow_route || found_allowed)) break;
 	    }
 	}
-    } else { /* client is set */
-	/* We know the origin is a tunnel - packet must be for the host */
-	if (subnet_matches_list(&st->networks,dest)) {
-	    st->deliver_to_host(st->dst,NULL,buf);
+    }
+    if (best_match==-1) {
+	/* The packet's not going down a tunnel.  It might (ought to)
+	   be for the host.   */
+	if (ipset_contains_addr(st->networks,dest)) {
+	    st->deliver_to_host(st->dst,buf);
+	    st->outcount++;
 	    BUF_ASSERT_FREE(buf);
 	} else {
-	    Message(M_ERROR,"%s: packet from tunnel %s can't be delivered "
-		    "to the host\n",st->name,client->name);
+	    string_t s,d;
+	    s=ipaddr_to_string(source);
+	    d=ipaddr_to_string(dest);
+	    Message(M_ERR,"%s: don't know where to deliver packet "
+		    "(s=%s, d=%s)\n", st->name, s, d);
+	    free(s); free(d);
 	    netlink_icmp_simple(st,buf,client,3,0);
 	    BUF_FREE(buf);
 	}
+    } else {
+	if (!allow_route &&
+	    !(st->routes[best_match]->options&OPT_ALLOWROUTE)) {
+	    string_t s,d;
+	    s=ipaddr_to_string(source);
+	    d=ipaddr_to_string(dest);
+	    /* We have a usable route but aren't allowed to use it.
+	       Generate ICMP destination unreachable: communication
+	       with destination network administratively prohibited */
+	    Message(M_NOTICE,"%s: denied forwarding for packet (s=%s, d=%s)\n",
+		    st->name,s,d);
+	    free(s); free(d);
+		    
+	    netlink_icmp_simple(st,buf,client,3,9);
+	    BUF_FREE(buf);
+	}
+	if (best_quality>0) {
+	    /* XXX Fragment if required */
+	    st->routes[best_match]->deliver(
+		st->routes[best_match]->dst, buf);
+	    st->routes[best_match]->outcount++;
+	    BUF_ASSERT_FREE(buf);
+	} else {
+	    /* Generate ICMP destination unreachable */
+	    netlink_icmp_simple(st,buf,client,3,0); /* client==NULL */
+	    BUF_FREE(buf);
+	}
     }
     BUF_ASSERT_FREE(buf);
 }
@@ -366,6 +411,8 @@ static void netlink_packet_local(struct netlink *st,
 {
     struct icmphdr *h;
 
+    st->localcount++;
+
     h=(struct icmphdr *)buf->start;
 
     if ((ntohs(h->iph.frag_off)&0xbfff)!=0) {
@@ -403,10 +450,9 @@ static void netlink_packet_local(struct netlink *st,
 
 /* If cid==NULL packet is from host, otherwise cid specifies which tunnel 
    it came from. */
-static void netlink_incoming(void *sst, void *cid, struct buffer_if *buf)
+static void netlink_incoming(struct netlink *st, struct netlink_client *client,
+			     struct buffer_if *buf)
 {
-    struct netlink *st=sst;
-    struct netlink_client *client=cid;
     uint32_t source,dest;
     struct iphdr *iph;
 
@@ -422,11 +468,13 @@ static void netlink_incoming(void *sst, void *cid, struct buffer_if *buf)
     source=ntohl(iph->saddr);
     dest=ntohl(iph->daddr);
 
-    /* Check source */
+    /* Check source. If we don't like the source, there's no point
+       generating ICMP because we won't know how to get it to the
+       source of the packet. */
     if (client) {
-	/* Check that the packet source is in 'nets' and its destination is
-	   in st->networks */
-	if (!subnet_matches_list(client->networks,source)) {
+	/* Check that the packet source is appropriate for the tunnel
+	   it came down */
+	if (!ipset_contains_addr(client->networks,source)) {
 	    string_t s,d;
 	    s=ipaddr_to_string(source);
 	    d=ipaddr_to_string(dest);
@@ -437,7 +485,10 @@ static void netlink_incoming(void *sst, void *cid, struct buffer_if *buf)
 	    return;
 	}
     } else {
-	if (!subnet_matches_list(&st->networks,source)) {
+	/* Check that the packet originates in our configured local
+	   network, and hasn't been forwarded from elsewhere or
+	   generated with the wrong source address */
+	if (!ipset_contains_addr(st->networks,source)) {
 	    string_t s,d;
 	    s=ipaddr_to_string(source);
 	    d=ipaddr_to_string(dest);
@@ -448,148 +499,121 @@ static void netlink_incoming(void *sst, void *cid, struct buffer_if *buf)
 	    return;
 	}
     }
-    /* (st->secnet_address needs checking before matching destination
-       addresses) */
+
+    /* If this is a point-to-point device we don't examine the
+       destination address at all; we blindly send it down our
+       one-and-only registered tunnel, or to the host, depending on
+       where it came from.  It's up to external software to check
+       address validity and generate ICMP, etc. */
+    if (st->ptp) {
+	if (client) {
+	    st->deliver_to_host(st->dst,buf);
+	} else {
+	    st->clients->deliver(st->clients->dst,buf);
+	}
+	BUF_ASSERT_FREE(buf);
+	return;
+    }
+
+    /* st->secnet_address needs checking before matching destination
+       addresses */
     if (dest==st->secnet_address) {
 	netlink_packet_local(st,client,buf);
 	BUF_ASSERT_FREE(buf);
 	return;
     }
-    if (client) {
-	if (!subnet_matches_list(&st->networks,dest)) {
-	    string_t s,d;
-	    s=ipaddr_to_string(source);
-	    d=ipaddr_to_string(dest);
-	    Message(M_WARNING,"%s: incoming packet from tunnel %s "
-		    "with bad destination address "
-		    "(s=%s,d=%s)\n",st->name,client->name,s,d);
-	    free(s); free(d);
-	    BUF_FREE(buf);
-	    return;
-	}
-    }
     netlink_packet_forward(st,client,buf);
     BUF_ASSERT_FREE(buf);
 }
 
-static void netlink_set_softlinks(struct netlink *st, struct netlink_client *c,
-				  bool_t up)
+static void netlink_inst_incoming(void *sst, struct buffer_if *buf)
 {
-    uint32_t i;
+    struct netlink_client *c=sst;
+    struct netlink *st=c->nst;
 
-    if (!st->routes) return; /* Table has not yet been created */
-    for (i=0; i<st->n_routes; i++) {
-	if (!st->routes[i].hard && st->routes[i].c==c) {
-	    st->routes[i].up=up;
-	    st->set_route(st->dst,&st->routes[i]);
-	}
-    }
+    netlink_incoming(st,c,buf);
 }
 
-static void netlink_set_quality(void *sst, void *cid, uint32_t quality)
+static void netlink_dev_incoming(void *sst, struct buffer_if *buf)
 {
     struct netlink *st=sst;
-    struct netlink_client *c=cid;
 
-    c->link_quality=quality;
-    if (c->link_quality==LINK_QUALITY_DOWN) {
-	netlink_set_softlinks(st,c,False);
-    } else {
-	netlink_set_softlinks(st,c,True);
-    }
+    netlink_incoming(st,NULL,buf);
 }
 
-static void *netlink_regnets(void *sst, struct subnet_list *nets,
-			     netlink_deliver_fn *deliver, void *dst,
-			     uint32_t max_start_pad, uint32_t max_end_pad,
-			     bool_t hard_routes, string_t client_name)
+static void netlink_set_quality(void *sst, uint32_t quality)
 {
-    struct netlink *st=sst;
-    struct netlink_client *c;
-
-    Message(M_DEBUG_CONFIG,"netlink_regnets: request for %d networks, "
-	    "max_start_pad=%d, max_end_pad=%d\n",
-	    nets->entries,max_start_pad,max_end_pad);
+    struct netlink_client *c=sst;
+    struct netlink *st=c->nst;
 
-    if (!hard_routes && !st->set_route) {
-	Message(M_ERROR,"%s: this netlink device does not support "
-		"soft routes.\n");
-	return NULL;
+    c->link_quality=quality;
+    c->up=(c->link_quality==LINK_QUALITY_DOWN)?False:True;
+    if (c->options&OPT_SOFTROUTE) {
+	st->set_routes(st->dst,c);
     }
+}
 
-    if (!hard_routes) {
-	/* XXX for now we assume that soft routes require root privilege;
-	   this may not always be true. */
-	require_root_privileges=True;
-	require_root_privileges_explanation="netlink: soft routes";
-    }
+static void netlink_output_subnets(struct netlink *st, uint32_t loglevel,
+				   struct subnet_list *snets)
+{
+    uint32_t i;
+    string_t net;
 
-#if 0
-    /* XXX POLICY: do we check nets against local networks?  If we do,
-       that prevents things like laptop tunnels working.  Perhaps we
-       can have a configuration option for this.  Or, if the admin
-       really doesn't want remote sites to be able to claim local
-       addresses, he can list them in exclude-remote-networks. */
-    if (subnet_lists_intersect(&st->networks,nets)) {
-	Message(M_ERROR,"%s: site %s specifies networks that "
-		"intersect with our local networks\n",st->name,client_name);
-	return False;
-    }
-#endif /* 0 */
-    /* Check that nets do not intersect st->exclude_remote_networks;
-       refuse to register if they do. */
-    if (subnet_lists_intersect(&st->exclude_remote_networks,nets)) {
-	Message(M_ERROR,"%s: site %s specifies networks that "
-		"intersect with the explicitly excluded remote networks\n",
-		st->name,client_name);
-	return False;
+    for (i=0; i<snets->entries; i++) {
+	net=subnet_to_string(snets->list[i]);
+	Message(loglevel,"%s ",net);
+	free(net);
     }
-
-    c=safe_malloc(sizeof(*c),"netlink_regnets");
-    c->networks=nets;
-    c->deliver=deliver;
-    c->dst=dst;
-    c->name=client_name; /* XXX copy it? */
-    c->hard_routes=hard_routes;
-    c->link_quality=LINK_QUALITY_DOWN;
-    c->next=st->clients;
-    st->clients=c;
-    if (max_start_pad > st->max_start_pad) st->max_start_pad=max_start_pad;
-    if (max_end_pad > st->max_end_pad) st->max_end_pad=max_end_pad;
-    st->n_routes+=nets->entries;
-
-    return c;
 }
 
-static void netlink_dump_routes(struct netlink *st)
+static void netlink_dump_routes(struct netlink *st, bool_t requested)
 {
     int i;
     string_t net;
+    uint32_t c=M_INFO;
 
-    Message(M_INFO,"%s: routing table:\n",st->name);
-    for (i=0; i<st->n_routes; i++) {
-	net=subnet_to_string(&st->routes[i].net);
-	Message(M_INFO,"%s -> tunnel %s (%s,%s)\n",net,st->routes[i].c->name,
-		st->routes[i].hard?"hard":"soft",
-		st->routes[i].up?"up":"down");
+    if (requested) c=M_WARNING;
+    if (st->ptp) {
+	net=ipaddr_to_string(st->secnet_address);
+	Message(c,"%s: point-to-point (remote end is %s); routes:\n",
+		st->name, net);
 	free(net);
-    }
-    Message(M_INFO,"%s/32 -> netlink \"%s\"\n",
-	    ipaddr_to_string(st->secnet_address),st->name);
-    for (i=0; i<st->networks.entries; i++) {
-	net=subnet_to_string(&st->networks.list[i]);
-	Message(M_INFO,"%s -> host\n",net);
+	netlink_output_subnets(st,c,st->clients->subnets);
+	Message(c,"\n");
+    } else {
+	Message(c,"%s: routing table:\n",st->name);
+	for (i=0; i<st->n_clients; i++) {
+	    netlink_output_subnets(st,c,st->routes[i]->subnets);
+	    Message(c,"-> tunnel %s (%s,%s routes,%s,quality %d,use %d)\n",
+		    st->routes[i]->name,
+		    st->routes[i]->options&OPT_SOFTROUTE?"soft":"hard",
+		    st->routes[i]->options&OPT_ALLOWROUTE?"free":"restricted",
+		    st->routes[i]->up?"up":"down",
+		    st->routes[i]->link_quality,
+		    st->routes[i]->outcount);
+	}
+	net=ipaddr_to_string(st->secnet_address);
+	Message(c,"%s/32 -> netlink \"%s\" (use %d)\n",
+		net,st->name,st->localcount);
 	free(net);
+	for (i=0; i<st->subnets->entries; i++) {
+	    net=subnet_to_string(st->subnets->list[i]);
+	    Message(c,"%s ",net);
+	    free(net);
+	}
+	if (i>0)
+	    Message(c,"-> host (use %d)\n",st->outcount);
     }
 }
 
-static int netlink_compare_route_specificity(const void *ap, const void *bp)
+/* ap is a pointer to a member of the routes array */
+static int netlink_compare_client_priority(const void *ap, const void *bp)
 {
-    const struct netlink_route *a=ap;
-    const struct netlink_route *b=bp;
+    const struct netlink_client *const*a=ap;
+    const struct netlink_client *const*b=bp;
 
-    if (a->net.len==b->net.len) return 0;
-    if (a->net.len<b->net.len) return 1;
+    if ((*a)->priority==(*b)->priority) return 0;
+    if ((*a)->priority<(*b)->priority) return 1;
     return -1;
 }
 
@@ -597,80 +621,263 @@ static void netlink_phase_hook(void *sst, uint32_t new_phase)
 {
     struct netlink *st=sst;
     struct netlink_client *c;
-    uint32_t i,j;
+    uint32_t i;
 
     /* All the networks serviced by the various tunnels should now
      * have been registered.  We build a routing table by sorting the
-     * routes into most-specific-first order.  */
-    st->routes=safe_malloc(st->n_routes*sizeof(*st->routes),
+     * clients by priority.  */
+    st->routes=safe_malloc(st->n_clients*sizeof(*st->routes),
 			   "netlink_phase_hook");
     /* Fill the table */
     i=0;
-    for (c=st->clients; c; c=c->next) {
-	for (j=0; j<c->networks->entries; j++) {
-	    st->routes[i].net=c->networks->list[j];
-	    st->routes[i].c=c;
-	    st->routes[i].up=c->hard_routes; /* Hard routes are always up;
-						soft routes default to down */
-	    st->routes[i].kup=False;
-	    st->routes[i].hard=c->hard_routes;
-	    i++;
+    for (c=st->clients; c; c=c->next)
+	st->routes[i++]=c;
+    /* Sort the table in descending order of priority */
+    qsort(st->routes,st->n_clients,sizeof(*st->routes),
+	  netlink_compare_client_priority);
+
+    netlink_dump_routes(st,False);
+}
+
+static void netlink_signal_handler(void *sst, int signum)
+{
+    struct netlink *st=sst;
+    Message(M_INFO,"%s: route dump requested by SIGUSR1\n",st->name);
+    netlink_dump_routes(st,True);
+}
+
+static void netlink_inst_output_config(void *sst, struct buffer_if *buf)
+{
+/*    struct netlink_client *c=sst; */
+/*    struct netlink *st=c->nst; */
+
+    /* For now we don't output anything */
+    BUF_ASSERT_USED(buf);
+}
+
+static bool_t netlink_inst_check_config(void *sst, struct buffer_if *buf)
+{
+/*    struct netlink_client *c=sst; */
+/*    struct netlink *st=c->nst; */
+
+    BUF_ASSERT_USED(buf);
+    /* We need to eat all of the configuration information from the buffer
+       for backward compatibility. */
+    buf->size=0;
+    return True;
+}
+
+static void netlink_inst_set_mtu(void *sst, uint32_t new_mtu)
+{
+    struct netlink_client *c=sst;
+
+    c->mtu=new_mtu;
+}
+
+static void netlink_inst_reg(void *sst, netlink_deliver_fn *deliver, 
+			     void *dst, uint32_t max_start_pad,
+			     uint32_t max_end_pad)
+{
+    struct netlink_client *c=sst;
+    struct netlink *st=c->nst;
+
+    if (max_start_pad > st->max_start_pad) st->max_start_pad=max_start_pad;
+    if (max_end_pad > st->max_end_pad) st->max_end_pad=max_end_pad;
+    c->deliver=deliver;
+    c->dst=dst;
+}
+
+static struct flagstr netlink_option_table[]={
+    { "soft", OPT_SOFTROUTE },
+    { "allow-route", OPT_ALLOWROUTE },
+    { NULL, 0}
+};
+/* This is the routine that gets called when the closure that's
+   returned by an invocation of a netlink device closure (eg. tun,
+   userv-ipif) is invoked.  It's used to create routes and pass in
+   information about them; the closure it returns is used by site
+   code.  */
+static closure_t *netlink_inst_create(struct netlink *st,
+				      struct cloc loc, dict_t *dict)
+{
+    struct netlink_client *c;
+    string_t name;
+    struct ipset *networks;
+    uint32_t options,priority,mtu;
+    list_t *l;
+
+    name=dict_read_string(dict, "name", True, st->name, loc);
+
+    l=dict_lookup(dict,"routes");
+    if (!l)
+	cfgfatal(loc,st->name,"required parameter \"routes\" not found\n");
+    networks=string_list_to_ipset(l,loc,st->name,"routes");
+    options=string_list_to_word(dict_lookup(dict,"options"),
+				netlink_option_table,st->name);
+
+    priority=dict_read_number(dict,"priority",False,st->name,loc,0);
+    mtu=dict_read_number(dict,"mtu",False,st->name,loc,0);
+
+    if ((options&OPT_SOFTROUTE) && !st->set_routes) {
+	cfgfatal(loc,st->name,"this netlink device does not support "
+		 "soft routes.\n");
+	return NULL;
+    }
+
+    if (options&OPT_SOFTROUTE) {
+	/* XXX for now we assume that soft routes require root privilege;
+	   this may not always be true. The device driver can tell us. */
+	require_root_privileges=True;
+	require_root_privileges_explanation="netlink: soft routes";
+	if (st->ptp) {
+	    cfgfatal(loc,st->name,"point-to-point netlinks do not support "
+		     "soft routes.\n");
+	    return NULL;
 	}
     }
-    /* ASSERT i==st->n_routes */
-    if (i!=st->n_routes) {
-	fatal("netlink: route count error: expected %d got %d\n",
-	      st->n_routes,i);
+
+    /* Check that nets are a subset of st->remote_networks;
+       refuse to register if they are not. */
+    if (!ipset_is_subset(st->remote_networks,networks)) {
+	cfgfatal(loc,st->name,"routes are not allowed\n");
+	return NULL;
+    }
+
+    c=safe_malloc(sizeof(*c),"netlink_inst_create");
+    c->cl.description=name;
+    c->cl.type=CL_NETLINK;
+    c->cl.apply=NULL;
+    c->cl.interface=&c->ops;
+    c->ops.st=c;
+    c->ops.reg=netlink_inst_reg;
+    c->ops.deliver=netlink_inst_incoming;
+    c->ops.set_quality=netlink_set_quality;
+    c->ops.output_config=netlink_inst_output_config;
+    c->ops.check_config=netlink_inst_check_config;
+    c->ops.set_mtu=netlink_inst_set_mtu;
+    c->nst=st;
+
+    c->networks=networks;
+    c->subnets=ipset_to_subnet_list(networks);
+    c->priority=priority;
+    c->deliver=NULL;
+    c->dst=NULL;
+    c->name=name;
+    c->link_quality=LINK_QUALITY_DOWN;
+    c->mtu=mtu?mtu:st->mtu;
+    c->options=options;
+    c->outcount=0;
+    c->up=False;
+    c->kup=False;
+    c->next=st->clients;
+    st->clients=c;
+    st->n_clients++;
+
+    return &c->cl;
+}
+
+static list_t *netlink_inst_apply(closure_t *self, struct cloc loc,
+				  dict_t *context, list_t *args)
+{
+    struct netlink *st=self->interface;
+
+    dict_t *dict;
+    item_t *item;
+    closure_t *cl;
+
+    item=list_elem(args,0);
+    if (!item || item->type!=t_dict) {
+	cfgfatal(loc,st->name,"must have a dictionary argument\n");
     }
-    /* Sort the table in descending order of specificity */
-    qsort(st->routes,st->n_routes,sizeof(*st->routes),
-	  netlink_compare_route_specificity);
+    dict=item->data.dict;
 
-    netlink_dump_routes(st);
+    cl=netlink_inst_create(st,loc,dict);
+
+    return new_closure(cl);
 }
 
 netlink_deliver_fn *netlink_init(struct netlink *st,
 				 void *dst, struct cloc loc,
 				 dict_t *dict, string_t description,
-				 netlink_route_fn *set_route,
+				 netlink_route_fn *set_routes,
 				 netlink_deliver_fn *to_host)
 {
+    item_t *sa, *ptpa;
+    list_t *l;
+
     st->dst=dst;
     st->cl.description=description;
-    st->cl.type=CL_NETLINK;
-    st->cl.apply=NULL;
-    st->cl.interface=&st->ops;
-    st->ops.st=st;
-    st->ops.regnets=netlink_regnets;
-    st->ops.deliver=netlink_incoming;
-    st->ops.set_quality=netlink_set_quality;
+    st->cl.type=CL_PURE;
+    st->cl.apply=netlink_inst_apply;
+    st->cl.interface=st;
     st->max_start_pad=0;
     st->max_end_pad=0;
     st->clients=NULL;
-    st->set_route=set_route;
+    st->routes=NULL;
+    st->n_clients=0;
+    st->set_routes=set_routes;
     st->deliver_to_host=to_host;
 
-    st->name=dict_read_string(dict,"name",False,"netlink",loc);
+    st->name=dict_read_string(dict,"name",False,description,loc);
     if (!st->name) st->name=description;
-    dict_read_subnet_list(dict, "networks", True, "netlink", loc,
-			  &st->networks);
-    dict_read_subnet_list(dict, "exclude-remote-networks", False, "netlink",
-			  loc, &st->exclude_remote_networks);
-    /* local-address and secnet-address do not have to be in local-networks;
-       however, they should be advertised in the 'sites' file for the
-       local site. */
-    st->local_address=string_to_ipaddr(
-	dict_find_item(dict,"local-address", True, "netlink", loc),"netlink");
-    st->secnet_address=string_to_ipaddr(
-	dict_find_item(dict,"secnet-address", True, "netlink", loc),"netlink");
+    l=dict_lookup(dict,"networks");
+    if (l) 
+	st->networks=string_list_to_ipset(l,loc,st->name,"networks");
+    else {
+	Message(M_WARNING,"%s: no local networks (parameter \"networks\") "
+		"defined\n",st->name);
+	st->networks=ipset_new();
+    }
+    l=dict_lookup(dict,"remote-networks");
+    if (l) {
+	st->remote_networks=string_list_to_ipset(l,loc,st->name,
+						 "remote-networks");
+    } else {
+	struct ipset *empty;
+	empty=ipset_new();
+	st->remote_networks=ipset_complement(empty);
+	ipset_free(empty);
+    }
+
+    sa=dict_find_item(dict,"secnet-address",False,"netlink",loc);
+    ptpa=dict_find_item(dict,"ptp-address",False,"netlink",loc);
+    if (sa && ptpa) {
+	cfgfatal(loc,st->name,"you may not specify secnet-address and "
+		 "ptp-address in the same netlink device\n");
+    }
+    if (!(sa || ptpa)) {
+	cfgfatal(loc,st->name,"you must specify secnet-address or "
+		 "ptp-address for this netlink device\n");
+    }
+    if (sa) {
+	st->secnet_address=string_item_to_ipaddr(sa,"netlink");
+	st->ptp=False;
+    } else {
+	st->secnet_address=string_item_to_ipaddr(ptpa,"netlink");
+	st->ptp=True;
+    }
+    /* To be strictly correct we could subtract secnet_address from
+       networks here.  It shouldn't make any practical difference,
+       though, and will make the route dump look complicated... */
+    st->subnets=ipset_to_subnet_list(st->networks);
     st->mtu=dict_read_number(dict, "mtu", False, "netlink", loc, DEFAULT_MTU);
     buffer_new(&st->icmp,ICMP_BUFSIZE);
-    st->n_routes=0;
-    st->routes=NULL;
+    st->outcount=0;
+    st->localcount=0;
 
     add_hook(PHASE_SETUP,netlink_phase_hook,st);
-
-    return netlink_incoming;
+    request_signal_notification(SIGUSR1, netlink_signal_handler, st);
+
+    /* If we're point-to-point then we return a CL_NETLINK directly,
+       rather than a CL_NETLINK_OLD or pure closure (depending on
+       compatibility).  This CL_NETLINK is for our one and only
+       client.  Our cl.apply function is NULL. */
+    if (st->ptp) {
+	closure_t *cl;
+	cl=netlink_inst_create(st,loc,dict);
+	st->cl=*cl;
+    }
+    return netlink_dev_incoming;
 }
 
 /* No connection to the kernel at all... */
@@ -679,23 +886,21 @@ struct null {
     struct netlink nl;
 };
 
-static bool_t null_set_route(void *sst, struct netlink_route *route)
+static bool_t null_set_route(void *sst, struct netlink_client *routes)
 {
     struct null *st=sst;
-    string_t t;
-
-    if (route->up!=route->kup) {
-	t=subnet_to_string(&route->net);
-	Message(M_INFO,"%s: setting route %s to state %s\n",st->nl.name,
-		t, route->up?"up":"down");
-	free(t);
-	route->kup=route->up;
+
+    if (routes->up!=routes->kup) {
+	Message(M_INFO,"%s: setting routes for tunnel %s to state %s\n",
+		st->nl.name,routes->name,
+		routes->up?"up":"down");
+	routes->kup=routes->up;
 	return True;
     }
     return False;
 }
 	    
-static void null_deliver(void *sst, void *cid, struct buffer_if *buf)
+static void null_deliver(void *sst, struct buffer_if *buf)
 {
     return;
 }