X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=secnet.git;a=blobdiff_plain;f=netlink.c;h=4426a7c3575d31f79d1a8293a135d5cfe9d9cd02;hp=f77d6bd8ff4ddd9813723b4ac3de12ea4822bb6f;hb=469fd1d95b2528212a46b155cb115c078de4228f;hpb=c6f79b178fe27ee315055dccb371b63ca1a6183a

diff --git a/netlink.c b/netlink.c
index f77d6bd..4426a7c 100644
--- a/netlink.c
+++ b/netlink.c
@@ -14,6 +14,9 @@
 #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)
 {
@@ -177,11 +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);
@@ -254,9 +265,8 @@ 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.  */
 static void netlink_packet_deliver(struct netlink *st,
 				   struct netlink_client *client,
 				   struct buffer_if *buf)
@@ -265,84 +275,105 @@ 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;
     }
     
-    /* XXX we're going to need an extra value 'allow_route' for the
-       source of the packet. It's always True for packets from the
-       host. For packets from tunnels, we consult the client
-       options. If !allow_route and the destination is a tunnel that
-       also doesn't allow routing, we must reject the packet with an
-       'administratively prohibited' or something similar ICMP. */
-    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) will 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_routes; i++) {
+	if (st->routes[i].up && subnet_match(&st->routes[i].net,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].c->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].c->link_quality>best_quality
+		|| best_quality==0) {
+		best_quality=st->routes[i].c->link_quality;
+		best_match=i;
+		if (st->routes[i].c->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 */
-	/* XXX THIS IS NOT NECESSARILY TRUE, AND NEEDS FIXING */
-	/* THIS FUNCTION MUST JUST DELIVER THE PACKET: IT MUST ASSUME
-	   THE PACKET HAS ALREADY BEEN CHECKED */
+    }
+    if (best_match==-1) {
+	/* The packet's not going down a tunnel.  It might (ought to)
+	   be for the host.   */
 	if (subnet_matches_list(&st->networks,dest)) {
-	    st->deliver_to_host(st->dst,NULL,buf);
+	    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].c->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) {
+	    st->routes[best_match].c->deliver(
+		st->routes[best_match].c->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);
 }
@@ -377,6 +408,8 @@ 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) {
@@ -414,10 +447,9 @@ 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;
 
@@ -437,7 +469,7 @@ static void netlink_incoming(void *sst, void *cid, struct buffer_if *buf)
     if (client) {
 	/* Check that the packet source is appropriate for the tunnel
 	   it came down */
-	if (!subnet_matches_list(client->networks,source)) {
+	if (!subnet_matches_list(&client->networks,source)) {
 	    string_t s,d;
 	    s=ipaddr_to_string(source);
 	    d=ipaddr_to_string(dest);
@@ -468,9 +500,9 @@ static void netlink_incoming(void *sst, void *cid, struct buffer_if *buf)
        or to the host, depending on where it came from. */
     if (st->ptp) {
 	if (client) {
-	    st->deliver_to_host(st->dst,NULL,buf);
+	    st->deliver_to_host(st->dst,buf);
 	} else {
-	    st->clients->deliver(st->clients->dst,NULL,buf);
+	    st->clients->deliver(st->clients->dst,buf);
 	}
 	BUF_ASSERT_FREE(buf);
 	return;
@@ -501,6 +533,21 @@ static void netlink_incoming(void *sst, void *cid, struct buffer_if *buf)
     BUF_ASSERT_FREE(buf);
 }
 
+static void netlink_inst_incoming(void *sst, struct buffer_if *buf)
+{
+    struct netlink_client *c=sst;
+    struct netlink *st=c->nst;
+
+    netlink_incoming(st,c,buf);
+}
+
+static void netlink_dev_incoming(void *sst, struct buffer_if *buf)
+{
+    struct netlink *st=sst;
+
+    netlink_incoming(st,NULL,buf);
+}
+
 static void netlink_set_softlinks(struct netlink *st, struct netlink_client *c,
 				  bool_t up, uint32_t quality)
 {
@@ -518,10 +565,10 @@ static void netlink_set_softlinks(struct netlink *st, struct netlink_client *c,
     }
 }
 
-static void netlink_set_quality(void *sst, void *cid, uint32_t quality)
+static void netlink_set_quality(void *sst, uint32_t quality)
 {
-    struct netlink *st=sst;
-    struct netlink_client *c=cid;
+    struct netlink_client *c=sst;
+    struct netlink *st=c->nst;
 
     c->link_quality=quality;
     if (c->link_quality==LINK_QUALITY_DOWN) {
@@ -531,62 +578,6 @@ static void netlink_set_quality(void *sst, void *cid, uint32_t quality)
     }
 }
 
-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,
-			     uint32_t options, string_t client_name)
-{
-    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);
-
-    if ((options&NETLINK_OPTION_SOFTROUTE) && !st->set_route) {
-	Message(M_ERROR,"%s: this netlink device does not support "
-		"soft routes.\n");
-	return NULL;
-    }
-
-    if (options&NETLINK_OPTION_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";
-    }
-
-    /* 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 NULL;
-    }
-
-    if (st->clients && st->ptp) {
-	fatal("%s: only one site may use a point-to-point netlink device\n",
-	      st->name);
-	return NULL;
-    }
-
-    c=safe_malloc(sizeof(*c),"netlink_regnets");
-    c->networks=nets;
-    c->deliver=deliver;
-    c->dst=dst;
-    c->name=client_name;
-    c->options=options;
-    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, bool_t requested)
 {
     int i;
@@ -594,23 +585,39 @@ static void netlink_dump_routes(struct netlink *st, bool_t requested)
     uint32_t c=M_INFO;
 
     if (requested) c=M_WARNING;
-    Message(c,"%s: routing table:\n",st->name);
-    for (i=0; i<st->n_routes; i++) {
-	net=subnet_to_string(&st->routes[i].net);
-	Message(c,"%s -> tunnel %s (%s,%s route,%s,quality %d)\n",net,
-		st->routes[i].c->name,
-		st->routes[i].hard?"hard":"soft",
-		st->routes[i].allow_route?"free":"restricted",
-		st->routes[i].up?"up":"down",
-		st->routes[i].quality);
+    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(c,"%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(c,"%s -> host\n",net);
+	for (i=0; i<st->n_routes; i++) {
+	    net=subnet_to_string(&st->routes[i].net);
+	    Message(c,"%s ",net);
+	    free(net);
+	}
+	Message(c,"\n");
+    } else {
+	Message(c,"%s: routing table:\n",st->name);
+	for (i=0; i<st->n_routes; i++) {
+	    net=subnet_to_string(&st->routes[i].net);
+	    Message(c,"%s -> tunnel %s (%s,%s route,%s,quality %d,use %d)\n",net,
+		    st->routes[i].c->name,
+		    st->routes[i].hard?"hard":"soft",
+		    st->routes[i].allow_route?"free":"restricted",
+		    st->routes[i].up?"up":"down",
+		    st->routes[i].quality,
+		    st->routes[i].outcount);
+	    free(net);
+	}
+	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->networks.entries; i++) {
+	    net=subnet_to_string(&st->networks.list[i]);
+	    Message(c,"%s -> host (use %d)\n",net,st->outcount);
+	    free(net);
+	}
     }
 }
 
@@ -630,13 +637,6 @@ static void netlink_phase_hook(void *sst, uint32_t new_phase)
     struct netlink_client *c;
     uint32_t i,j;
 
-    if (!st->clients && st->ptp) {
-	/* Point-to-point netlink devices must have precisely one
-	   client. If none has registered by now, complain. */
-	fatal("%s: point-to-point netlink devices must have precisely "
-	      "one client. This one doesn't have any.\n",st->name);
-    }
-
     /* 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.  */
@@ -645,17 +645,21 @@ static void netlink_phase_hook(void *sst, uint32_t new_phase)
     /* 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];
+	for (j=0; j<c->networks.entries; j++) {
+	    st->routes[i].net=c->networks.list[j];
 	    st->routes[i].c=c;
 	    /* Hard routes are always up;
-	       soft routes default to down */
-	    st->routes[i].up=c->options&NETLINK_OPTION_SOFTROUTE?False:True;
+	       soft routes default to down; routes with no 'deliver' function
+	       default to down */
+	    st->routes[i].up=c->deliver?
+		(c->options&OPT_SOFTROUTE?False:True):
+		False;
 	    st->routes[i].kup=False;
-	    st->routes[i].hard=c->options&NETLINK_OPTION_SOFTROUTE?False:True;
-	    st->routes[i].allow_route=c->options&NETLINK_OPTION_ALLOW_ROUTE?
+	    st->routes[i].hard=c->options&OPT_SOFTROUTE?False:True;
+	    st->routes[i].allow_route=c->options&OPT_ALLOWROUTE?
 		True:False;
 	    st->routes[i].quality=c->link_quality;
+	    st->routes[i].outcount=0;
 	    i++;
 	}
     }
@@ -678,6 +682,116 @@ static void netlink_signal_handler(void *sst, int signum)
     netlink_dump_routes(st,True);
 }
 
+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 subnet_list networks;
+    uint32_t options;
+
+    name=dict_read_string(dict, "name", True, st->name, loc);
+
+    dict_read_subnet_list(dict, "routes", True, st->name, loc,
+			  &networks);
+    options=string_list_to_word(dict_lookup(dict,"options"),
+				netlink_option_table,st->name);
+
+    if ((options&OPT_SOFTROUTE) && !st->set_route) {
+	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;
+	}
+    }
+
+    /* Check that nets do not intersect st->exclude_remote_networks;
+       refuse to register if they do. */
+    if (subnet_lists_intersect(&st->exclude_remote_networks,&networks)) {
+	cfgfatal(loc,st->name,"networks intersect with the explicitly "
+		 "excluded remote networks\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->nst=st;
+
+    c->networks=networks;
+    c->deliver=NULL;
+    c->dst=NULL;
+    c->name=name;
+    c->options=options;
+    c->link_quality=LINK_QUALITY_DOWN;
+    c->next=st->clients;
+    st->clients=c;
+    st->n_routes+=networks.entries;
+
+    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;
+
+    Message(M_DEBUG_CONFIG,"netlink_inst_apply\n");
+
+    item=list_elem(args,0);
+    if (!item || item->type!=t_dict) {
+	cfgfatal(loc,st->name,"must have a dictionary argument\n");
+    }
+    dict=item->data.dict;
+
+    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,
@@ -688,13 +802,9 @@ netlink_deliver_fn *netlink_init(struct netlink *st,
 
     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;
@@ -707,11 +817,8 @@ netlink_deliver_fn *netlink_init(struct netlink *st,
 			  &st->networks);
     dict_read_subnet_list(dict, "exclude-remote-networks", False, "netlink",
 			  loc, &st->exclude_remote_networks);
-    /* secnet-address does not have to be in local-networks;
-       however, it should be advertised in the 'sites' file for the
-       local site. */
     sa=dict_find_item(dict,"secnet-address",False,"netlink",loc);
-    ptpa=dict_find_item(dict,"ptp-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");
@@ -731,11 +838,22 @@ netlink_deliver_fn *netlink_init(struct netlink *st,
     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);
     request_signal_notification(SIGUSR1, netlink_signal_handler, st);
 
-    return netlink_incoming;
+    /* 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... */
@@ -760,7 +878,7 @@ static bool_t null_set_route(void *sst, struct netlink_route *route)
     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;
 }