X-Git-Url: https://git.distorted.org.uk/~mdw/secnet/blobdiff_plain/975820aa67cb8f5f89eb968ec5397305e3b77bcf..cfd794827e3243c681590845063309fa628cfef4:/netlink.c

diff --git a/netlink.c b/netlink.c
index af6434f..87b6671 100644
--- a/netlink.c
+++ b/netlink.c
@@ -193,6 +193,10 @@ struct iphdr {
     uint16_t   tot_len;
     uint16_t   id;
     uint16_t   frag_off;
+#define IPHDR_FRAG_OFF  ((uint16_t)0x1fff)
+#define IPHDR_FRAG_MORE ((uint16_t)0x2000)
+#define IPHDR_FRAG_DONT ((uint16_t)0x4000)
+/*                 reserved        0x8000 */
     uint8_t    ttl;
     uint8_t    protocol;
     uint16_t   check;
@@ -206,7 +210,7 @@ struct icmphdr {
     uint8_t type;
     uint8_t code;
     uint16_t check;
-    union {
+    union icmpinfofield {
 	uint32_t unused;
 	struct {
 	    uint8_t pointer;
@@ -220,6 +224,8 @@ struct icmphdr {
 	} echo;
     } d;
 };
+
+static const union icmpinfofield icmp_noinfo;
     
 static void netlink_packet_deliver(struct netlink *st,
 				   struct netlink_client *client,
@@ -305,7 +311,7 @@ static bool_t netlink_icmp_may_reply(struct buffer_if *buf)
 	}
     }
     /* How do we spot broadcast destination addresses? */
-    if (ntohs(iph->frag_off)&0x1fff) return False; /* Non-initial fragment */
+    if (ntohs(iph->frag_off)&IPHDR_FRAG_OFF) return False;
     source=ntohl(iph->saddr);
     if (source==0) return False;
     if ((source&0xff000000)==0x7f000000) return False;
@@ -354,7 +360,8 @@ static uint16_t netlink_icmp_reply_len(struct buffer_if *buf)
    comes from. NULL indicates the host. */
 static void netlink_icmp_simple(struct netlink *st, struct buffer_if *buf,
 				struct netlink_client *client,
-				uint8_t type, uint8_t code)
+				uint8_t type, uint8_t code,
+				union icmpinfofield info)
 {
     struct icmphdr *h;
     uint16_t len;
@@ -363,7 +370,7 @@ static void netlink_icmp_simple(struct netlink *st, struct buffer_if *buf,
 	struct iphdr *iph=(struct iphdr *)buf->start;
 	len=netlink_icmp_reply_len(buf);
 	h=netlink_icmp_tmpl(st,ntohl(iph->saddr),len);
-	h->type=type; h->code=code;
+	h->type=type; h->code=code; h->d=info;
 	memcpy(buf_append(&st->icmp,len),buf->start,len);
 	netlink_icmp_csum(h);
 	netlink_packet_deliver(st,NULL,&st->icmp);
@@ -409,6 +416,28 @@ static bool_t netlink_check(struct netlink *st, struct buffer_if *buf,
 #undef BAD
 }
 
+/* Deliver a packet _to_ client; used after we have decided
+ * what to do with it (and just to check that the client has
+ * actually registered a delivery function with us). */
+static void netlink_client_deliver(struct netlink *st,
+				   struct netlink_client *client,
+				   uint32_t source, uint32_t dest,
+				   struct buffer_if *buf)
+{
+    if (!client->deliver) {
+	string_t s,d;
+	s=ipaddr_to_string(source);
+	d=ipaddr_to_string(dest);
+	Message(M_ERR,"%s: dropping %s->%s, client not registered\n",
+		st->name,s,d);
+	free(s); free(d);
+	BUF_FREE(buf);
+	return;
+    }
+    client->deliver(client->dst, buf);
+    client->outcount++;
+}
+
 /* 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.  */
@@ -499,7 +528,7 @@ static void netlink_packet_deliver(struct netlink *st,
 		    "(s=%s, d=%s)\n", st->name, s, d);
 	    free(s); free(d);
 	    netlink_icmp_simple(st,buf,client,ICMP_TYPE_UNREACHABLE,
-				ICMP_CODE_NET_UNREACHABLE);
+				ICMP_CODE_NET_UNREACHABLE, icmp_noinfo);
 	    BUF_FREE(buf);
 	}
     } else {
@@ -516,19 +545,20 @@ static void netlink_packet_deliver(struct netlink *st,
 	    free(s); free(d);
 		    
 	    netlink_icmp_simple(st,buf,client,ICMP_TYPE_UNREACHABLE,
-				ICMP_CODE_NET_PROHIBITED);
+				ICMP_CODE_NET_PROHIBITED, icmp_noinfo);
 	    BUF_FREE(buf);
 	} else {
 	    if (best_quality>0) {
 		/* XXX Fragment if required */
-		st->routes[best_match]->deliver(
-		    st->routes[best_match]->dst, buf);
-		st->routes[best_match]->outcount++;
+		netlink_client_deliver(st,st->routes[best_match],
+				       source,dest,buf);
 		BUF_ASSERT_FREE(buf);
 	    } else {
 		/* Generate ICMP destination unreachable */
-		netlink_icmp_simple(st,buf,client,ICMP_TYPE_UNREACHABLE,
-				    ICMP_CODE_NET_UNREACHABLE); /* client==NULL */
+		netlink_icmp_simple(st,buf,client,/* client==NULL */
+				    ICMP_TYPE_UNREACHABLE,
+				    ICMP_CODE_NET_UNREACHABLE,
+				    icmp_noinfo);
 		BUF_FREE(buf);
 	    }
 	}
@@ -549,7 +579,7 @@ static void netlink_packet_forward(struct netlink *st,
     if (iph->ttl<=1) {
 	/* Generate ICMP time exceeded */
 	netlink_icmp_simple(st,buf,client,ICMP_TYPE_TIME_EXCEEDED,
-			    ICMP_CODE_TTL_EXCEEDED);
+			    ICMP_CODE_TTL_EXCEEDED,icmp_noinfo);
 	BUF_FREE(buf);
 	return;
     }
@@ -578,7 +608,7 @@ static void netlink_packet_local(struct netlink *st,
     }
     h=(struct icmphdr *)buf->start;
 
-    if ((ntohs(h->iph.frag_off)&0xbfff)!=0) {
+    if ((ntohs(h->iph.frag_off)&(IPHDR_FRAG_OFF|IPHDR_FRAG_MORE))!=0) {
 	Message(M_WARNING,"%s: fragmented packet addressed to secnet; "
 		"ignoring it\n",st->name);
 	BUF_FREE(buf);
@@ -604,7 +634,7 @@ static void netlink_packet_local(struct netlink *st,
     } else {
 	/* Send ICMP protocol unreachable */
 	netlink_icmp_simple(st,buf,client,ICMP_TYPE_UNREACHABLE,
-			    ICMP_CODE_PROTOCOL_UNREACHABLE);
+			    ICMP_CODE_PROTOCOL_UNREACHABLE,icmp_noinfo);
 	BUF_FREE(buf);
 	return;
     }
@@ -678,7 +708,7 @@ static void netlink_incoming(struct netlink *st, struct netlink_client *client,
 	if (client) {
 	    st->deliver_to_host(st->dst,buf);
 	} else {
-	    st->clients->deliver(st->clients->dst,buf);
+	    netlink_client_deliver(st,st->clients,source,dest,buf);
 	}
 	BUF_ASSERT_FREE(buf);
 	return;
@@ -744,7 +774,7 @@ static void netlink_dump_routes(struct netlink *st, bool_t requested)
     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",
+	Message(c,"%s: point-to-point (remote end is %s); routes: ",
 		st->name, net);
 	free(net);
 	netlink_output_subnets(st,c,st->clients->subnets);