X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?a=blobdiff_plain;f=netlink.c;h=b7cdb4cdef4a4ca6496f18b2ffa0cd08f3900f57;hb=8dea8d37a13fcc615daba3375809900f04a2e5a2;hp=e09eacf95c4466015bf393eaf1fa75cdcd634073;hpb=7138d0c54cd2212439434d27cb2d6ea775c3039b;p=secnet.git

diff --git a/netlink.c b/netlink.c
index e09eacf..b7cdb4c 100644
--- a/netlink.c
+++ b/netlink.c
@@ -12,6 +12,7 @@
 #include "util.h"
 #include "ipaddr.h"
 #include "netlink.h"
+#include "process.h"
 
 /* Generic IP checksum routine */
 static inline uint16_t ip_csum(uint8_t *iph,uint32_t count)
@@ -176,11 +177,19 @@ 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);
@@ -434,8 +443,8 @@ static void netlink_incoming(void *sst, void *cid, struct buffer_if *buf)
 
     /* Check source */
     if (client) {
-	/* Check that the packet source is in 'nets' and its destination is
-	   in st->networks */
+	/* Check that the packet source is appropriate for the tunnel
+	   it came down */
 	if (!subnet_matches_list(client->networks,source)) {
 	    string_t s,d;
 	    s=ipaddr_to_string(source);
@@ -447,6 +456,9 @@ static void netlink_incoming(void *sst, void *cid, struct buffer_if *buf)
 	    return;
 	}
     } else {
+	/* 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 (!subnet_matches_list(&st->networks,source)) {
 	    string_t s,d;
 	    s=ipaddr_to_string(source);
@@ -458,6 +470,20 @@ static void netlink_incoming(void *sst, void *cid, struct buffer_if *buf)
 	    return;
 	}
     }
+
+    /* If this is a point-to-point device we don't examine the packet at
+       all; we blindly send it down our one-and-only registered tunnel,
+       or to the host, depending on where it came from. */
+    if (st->ptp) {
+	if (client) {
+	    st->deliver_to_host(st->dst,NULL,buf);
+	} else {
+	    st->clients->deliver(st->clients->dst,NULL,buf);
+	}
+	BUF_ASSERT_FREE(buf);
+	return;
+    }
+
     /* (st->secnet_address needs checking before matching destination
        addresses) */
     if (dest==st->secnet_address) {
@@ -484,15 +510,18 @@ static void netlink_incoming(void *sst, void *cid, struct buffer_if *buf)
 }
 
 static void netlink_set_softlinks(struct netlink *st, struct netlink_client *c,
-				  bool_t up)
+				  bool_t up, uint32_t quality)
 {
     uint32_t i;
 
     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]);
+	if (st->routes[i].c==c) {
+	    st->routes[i].quality=quality;
+	    if (!st->routes[i].hard) {
+		st->routes[i].up=up;
+		st->set_route(st->dst,&st->routes[i]);
+	    }
 	}
     }
 }
@@ -504,9 +533,9 @@ static void netlink_set_quality(void *sst, void *cid, uint32_t quality)
 
     c->link_quality=quality;
     if (c->link_quality==LINK_QUALITY_DOWN) {
-	netlink_set_softlinks(st,c,False);
+	netlink_set_softlinks(st,c,False,c->link_quality);
     } else {
-	netlink_set_softlinks(st,c,True);
+	netlink_set_softlinks(st,c,True,c->link_quality);
     }
 }
 
@@ -541,14 +570,20 @@ static void *netlink_regnets(void *sst, struct subnet_list *nets,
 	Message(M_ERROR,"%s: site %s specifies networks that "
 		"intersect with the explicitly excluded remote networks\n",
 		st->name,client_name);
-	return False;
+	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; /* XXX copy it? */
+    c->name=client_name;
     c->options=options;
     c->link_quality=LINK_QUALITY_DOWN;
     c->next=st->clients;
@@ -560,26 +595,29 @@ static void *netlink_regnets(void *sst, struct subnet_list *nets,
     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);
+    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(M_INFO,"%s -> tunnel %s (%s,%s route,%s)\n",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].up?"up":"down",
+		st->routes[i].quality);
 	free(net);
     }
-    Message(M_INFO,"%s/32 -> netlink \"%s\"\n",
+    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(M_INFO,"%s -> host\n",net);
+	Message(c,"%s -> host\n",net);
 	free(net);
     }
 }
@@ -600,6 +638,13 @@ 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.  */
@@ -618,6 +663,7 @@ static void netlink_phase_hook(void *sst, uint32_t new_phase)
 	    st->routes[i].hard=c->options&NETLINK_OPTION_SOFTROUTE?False:True;
 	    st->routes[i].allow_route=c->options&NETLINK_OPTION_ALLOW_ROUTE?
 		True:False;
+	    st->routes[i].quality=c->link_quality;
 	    i++;
 	}
     }
@@ -630,7 +676,14 @@ static void netlink_phase_hook(void *sst, uint32_t new_phase)
     qsort(st->routes,st->n_routes,sizeof(*st->routes),
 	  netlink_compare_route_specificity);
 
-    netlink_dump_routes(st);
+    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);
 }
 
 netlink_deliver_fn *netlink_init(struct netlink *st,
@@ -639,6 +692,8 @@ netlink_deliver_fn *netlink_init(struct netlink *st,
 				 netlink_route_fn *set_route,
 				 netlink_deliver_fn *to_host)
 {
+    item_t *sa, *ptpa;
+
     st->dst=dst;
     st->cl.description=description;
     st->cl.type=CL_NETLINK;
@@ -663,14 +718,30 @@ netlink_deliver_fn *netlink_init(struct netlink *st,
     /* secnet-address does not have to be in local-networks;
        however, it should be advertised in the 'sites' file for the
        local site. */
-    st->secnet_address=string_to_ipaddr(
-	dict_find_item(dict,"secnet-address", True, "netlink", loc),"netlink");
+    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_to_ipaddr(sa,"netlink");
+	st->ptp=False;
+    } else {
+	st->secnet_address=string_to_ipaddr(ptpa,"netlink");
+	st->ptp=True;
+    }
     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;
 
     add_hook(PHASE_SETUP,netlink_phase_hook,st);
+    request_signal_notification(SIGUSR1, netlink_signal_handler, st);
 
     return netlink_incoming;
 }