X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=secnet.git;a=blobdiff_plain;f=netlink.c;h=e197e80f8c69508f5f617d9af86b1bfa07957098;hp=2c3d12d4302b00aea1a59d44dbdd3ca130a532fc;hb=0e646750a699f6dac806c7752c81d160c4f78987;hpb=6e3fd952d7052293905334a3bb3911c775222ea6

diff --git a/netlink.c b/netlink.c
index 2c3d12d..e197e80 100644
--- a/netlink.c
+++ b/netlink.c
@@ -180,7 +180,7 @@ static inline uint16_t ip_fast_csum(const uint8_t *iph, int32_t ihl) {
     return sum;
 }
 #else
-static inline uint16_t ip_fast_csum(uint8_t *iph, int32_t ihl)
+static inline uint16_t ip_fast_csum(const uint8_t *iph, int32_t ihl)
 {
     assert(ihl < INT_MAX/4);
     return ip_csum(iph,ihl*4);
@@ -237,6 +237,20 @@ struct icmphdr {
 
 static const union icmpinfofield icmp_noinfo;
     
+static void netlink_client_deliver(struct netlink *st,
+				   struct netlink_client *client,
+				   uint32_t source, uint32_t dest,
+				   struct buffer_if *buf);
+static void netlink_host_deliver(struct netlink *st,
+				 struct netlink_client *sender,
+				 uint32_t source, uint32_t dest,
+				 struct buffer_if *buf);
+
+static const char *sender_name(struct netlink_client *sender /* or NULL */)
+{
+    return sender?sender->name:"(local)";
+}
+
 static void netlink_packet_deliver(struct netlink *st,
 				   struct netlink_client *client,
 				   struct buffer_if *buf);
@@ -249,7 +263,8 @@ static void netlink_packet_deliver(struct netlink *st,
    settable.
    */
 static struct icmphdr *netlink_icmp_tmpl(struct netlink *st,
-					 uint32_t dest,uint16_t len)
+					 uint32_t source, uint32_t dest,
+					 uint16_t len)
 {
     struct icmphdr *h;
 
@@ -265,7 +280,7 @@ static struct icmphdr *netlink_icmp_tmpl(struct netlink *st,
     h->iph.frag=0;
     h->iph.ttl=255; /* XXX should be configurable */
     h->iph.protocol=1;
-    h->iph.saddr=htonl(st->secnet_address);
+    h->iph.saddr=htonl(source);
     h->iph.daddr=htonl(dest);
     h->iph.check=0;
     h->iph.check=ip_fast_csum((uint8_t *)&h->iph,h->iph.ihl);
@@ -376,7 +391,9 @@ static uint16_t netlink_icmp_reply_len(struct buffer_if *buf)
 
 /* client indicates where the packet we're constructing a response to
    comes from. NULL indicates the host. */
-static void netlink_icmp_simple(struct netlink *st, struct buffer_if *buf,
+static void netlink_icmp_simple(struct netlink *st,
+				struct netlink_client *origsender,
+				struct buffer_if *buf,
 				uint8_t type, uint8_t code,
 				union icmpinfofield info)
 {
@@ -385,12 +402,44 @@ static void netlink_icmp_simple(struct netlink *st, struct buffer_if *buf,
 
     if (netlink_icmp_may_reply(buf)) {
 	struct iphdr *iph=(struct iphdr *)buf->start;
+
+	uint32_t icmpdest = ntohl(iph->saddr);
+	uint32_t icmpsource;
+	const char *icmpsourcedebugprefix;
+	if (!st->ptp) {
+	    icmpsource=st->secnet_address;
+	    icmpsourcedebugprefix="";
+	} else if (origsender) {
+	    /* was from peer, send reply as if from host */
+	    icmpsource=st->local_address;
+	    icmpsourcedebugprefix="L!";
+	} else {
+	    /* was from host, send reply as if from peer */
+	    icmpsource=st->secnet_address; /* actually, peer address */
+	    icmpsourcedebugprefix="P!";
+	}
+	MDEBUG("%s: generating ICMP re %s[%s]->[%s]:"
+	       " from %s%s type=%u code=%u\n",
+	       st->name, sender_name(origsender),
+	       ipaddr_to_string(ntohl(iph->saddr)),
+	       ipaddr_to_string(ntohl(iph->daddr)),
+	       icmpsourcedebugprefix,
+	       ipaddr_to_string(icmpsource),
+	       type, code);
+
 	len=netlink_icmp_reply_len(buf);
-	h=netlink_icmp_tmpl(st,ntohl(iph->saddr),len);
+	h=netlink_icmp_tmpl(st,icmpsource,icmpdest,len);
 	h->type=type; h->code=code; h->d=info;
-	memcpy(buf_append(&st->icmp,len),buf->start,len);
+	BUF_ADD_BYTES(append,&st->icmp,buf->start,len);
 	netlink_icmp_csum(h);
-	netlink_packet_deliver(st,NULL,&st->icmp);
+
+	if (!st->ptp) {
+	    netlink_packet_deliver(st,NULL,&st->icmp);
+	} else if (origsender) {
+	    netlink_client_deliver(st,origsender,icmpsource,icmpdest,&st->icmp);
+	} else {
+	    netlink_host_deliver(st,NULL,icmpsource,icmpdest,&st->icmp);
+	}
 	BUF_ASSERT_FREE(&st->icmp);
     }
 }
@@ -465,6 +514,7 @@ static const char *fragment_filter_header(uint8_t *base, long *hlp)
 
 /* Fragment or send ICMP Fragmentation Needed */
 static void netlink_maybe_fragment(struct netlink *st,
+				   struct netlink_client *sender,
 				   netlink_deliver_fn *deliver,
 				   void *deliver_dst,
 				   const char *delivery_name,
@@ -496,7 +546,7 @@ static void netlink_maybe_fragment(struct netlink *st,
     if (orig_frag&IPHDR_FRAG_DONT) {
 	union icmpinfofield info =
 	    { .fragneeded = { .unused = 0, .mtu = htons(mtu) } };
-	netlink_icmp_simple(st,buf,
+	netlink_icmp_simple(st,sender,buf,
 			    ICMP_TYPE_UNREACHABLE,
 			    ICMP_CODE_FRAGMENTATION_REQUIRED,
 			    info);
@@ -541,7 +591,7 @@ static void netlink_maybe_fragment(struct netlink *st,
 	long avail = mtu - hl;
 	long remain = endindata - indata;
 	long use = avail < remain ? (avail & ~(long)7) : remain;
-	memcpy(buf_append(buf, use), indata, use);
+	BUF_ADD_BYTES(append, buf, indata, use);
 	indata += use;
 
 	_Bool last_frag = indata >= endindata;
@@ -587,11 +637,10 @@ static void netlink_client_deliver(struct netlink *st,
 	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;
     }
-    netlink_maybe_fragment(st, client->deliver,client->dst,client->name,
+    netlink_maybe_fragment(st,NULL, client->deliver,client->dst,client->name,
 			   client->mtu, source,dest,buf);
     client->outcount++;
 }
@@ -599,24 +648,24 @@ static void netlink_client_deliver(struct netlink *st,
 /* Deliver a packet to the host; used after we have decided that that
  * is what to do with it. */
 static void netlink_host_deliver(struct netlink *st,
+				 struct netlink_client *sender,
 				 uint32_t source, uint32_t dest,
 				 struct buffer_if *buf)
 {
-    netlink_maybe_fragment(st, st->deliver_to_host,st->dst,"(host)",
+    netlink_maybe_fragment(st,sender, st->deliver_to_host,st->dst,"(host)",
 			   st->mtu, source,dest,buf);
     st->outcount++;
 }
 
-/* Deliver a packet. "client" is the _origin_ of the packet, not its
-   destination, and is NULL for packets from the host and packets
+/* Deliver a packet. "sender"==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 netlink_client *sender,
 				   struct buffer_if *buf)
 {
     if (buf->size < (int)sizeof(struct iphdr)) {
 	Message(M_ERR,"%s: trying to deliver a too-short packet"
-		" from %s!\n",st->name, client?client->name:"(local)");
+		" from %s!\n",st->name, sender_name(sender));
 	BUF_FREE(buf);
 	return;
     }
@@ -638,9 +687,9 @@ static void netlink_packet_deliver(struct netlink *st,
 	return;
     }
     
-    /* Packets from the host (client==NULL) may always be routed.  Packets
+    /* Packets from the host (sender==NULL) may always be routed.  Packets
        from clients with the allow_route option will also be routed. */
-    if (!client || (client && (client->options & OPT_ALLOWROUTE)))
+    if (!sender || (sender && (sender->options & OPT_ALLOWROUTE)))
 	allow_route=True;
 
     /* If !allow_route, we check the routing table anyway, and if
@@ -686,7 +735,7 @@ static void netlink_packet_deliver(struct netlink *st,
 	/* The packet's not going down a tunnel.  It might (ought to)
 	   be for the host.   */
 	if (ipset_contains_addr(st->networks,dest)) {
-	    netlink_host_deliver(st,source,dest,buf);
+	    netlink_host_deliver(st,sender,source,dest,buf);
 	    BUF_ASSERT_FREE(buf);
 	} else {
 	    string_t s,d;
@@ -694,8 +743,7 @@ static void netlink_packet_deliver(struct netlink *st,
 	    d=ipaddr_to_string(dest);
 	    Message(M_DEBUG,"%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,ICMP_TYPE_UNREACHABLE,
+	    netlink_icmp_simple(st,sender,buf,ICMP_TYPE_UNREACHABLE,
 				ICMP_CODE_NET_UNREACHABLE, icmp_noinfo);
 	    BUF_FREE(buf);
 	}
@@ -710,9 +758,8 @@ static void netlink_packet_deliver(struct netlink *st,
 	       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,ICMP_TYPE_UNREACHABLE,
+	    netlink_icmp_simple(st,sender,buf,ICMP_TYPE_UNREACHABLE,
 				ICMP_CODE_NET_PROHIBITED, icmp_noinfo);
 	    BUF_FREE(buf);
 	} else {
@@ -722,7 +769,7 @@ static void netlink_packet_deliver(struct netlink *st,
 		BUF_ASSERT_FREE(buf);
 	    } else {
 		/* Generate ICMP destination unreachable */
-		netlink_icmp_simple(st,buf,
+		netlink_icmp_simple(st,sender,buf,
 				    ICMP_TYPE_UNREACHABLE,
 				    ICMP_CODE_NET_UNREACHABLE,
 				    icmp_noinfo);
@@ -734,7 +781,7 @@ static void netlink_packet_deliver(struct netlink *st,
 }
 
 static void netlink_packet_forward(struct netlink *st, 
-				   struct netlink_client *client,
+				   struct netlink_client *sender,
 				   struct buffer_if *buf)
 {
     if (buf->size < (int)sizeof(struct iphdr)) return;
@@ -745,7 +792,7 @@ static void netlink_packet_forward(struct netlink *st,
     /* Packet has already been checked */
     if (iph->ttl<=1) {
 	/* Generate ICMP time exceeded */
-	netlink_icmp_simple(st,buf,ICMP_TYPE_TIME_EXCEEDED,
+	netlink_icmp_simple(st,sender,buf,ICMP_TYPE_TIME_EXCEEDED,
 			    ICMP_CODE_TTL_EXCEEDED,icmp_noinfo);
 	BUF_FREE(buf);
 	return;
@@ -754,13 +801,13 @@ static void netlink_packet_forward(struct netlink *st,
     iph->check=0;
     iph->check=ip_fast_csum((uint8_t *)iph,iph->ihl);
 
-    netlink_packet_deliver(st,client,buf);
+    netlink_packet_deliver(st,sender,buf);
     BUF_ASSERT_FREE(buf);
 }
 
 /* Deal with packets addressed explicitly to us */
 static void netlink_packet_local(struct netlink *st,
-				 struct netlink_client *client,
+				 struct netlink_client *sender,
 				 struct buffer_if *buf)
 {
     struct icmphdr *h;
@@ -803,7 +850,7 @@ static void netlink_packet_local(struct netlink *st,
 	Message(M_WARNING,"%s: unknown incoming ICMP\n",st->name);
     } else {
 	/* Send ICMP protocol unreachable */
-	netlink_icmp_simple(st,buf,ICMP_TYPE_UNREACHABLE,
+	netlink_icmp_simple(st,sender,buf,ICMP_TYPE_UNREACHABLE,
 			    ICMP_CODE_PROTOCOL_UNREACHABLE,icmp_noinfo);
 	BUF_FREE(buf);
 	return;
@@ -814,13 +861,13 @@ 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(struct netlink *st, struct netlink_client *client,
+static void netlink_incoming(struct netlink *st, struct netlink_client *sender,
 			     struct buffer_if *buf)
 {
     uint32_t source,dest;
     struct iphdr *iph;
     char errmsgbuf[50];
-    const char *sourcedesc=client?client->name:"host";
+    const char *sourcedesc=sender?sender->name:"host";
 
     BUF_ASSERT_USED(buf);
 
@@ -831,7 +878,7 @@ static void netlink_incoming(struct netlink *st, struct netlink_client *client,
 	BUF_FREE(buf);
 	return;
     }
-    assert(buf->size >= (int)sizeof(struct icmphdr));
+    assert(buf->size >= (int)sizeof(struct iphdr));
     iph=(struct iphdr *)buf->start;
 
     source=ntohl(iph->saddr);
@@ -840,16 +887,15 @@ static void netlink_incoming(struct netlink *st, struct netlink_client *client,
     /* 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) {
+    if (sender) {
 	/* Check that the packet source is appropriate for the tunnel
 	   it came down */
-	if (!ipset_contains_addr(client->networks,source)) {
+	if (!ipset_contains_addr(sender->networks,source)) {
 	    string_t s,d;
 	    s=ipaddr_to_string(source);
 	    d=ipaddr_to_string(dest);
 	    Message(M_WARNING,"%s: packet from tunnel %s with bad "
-		    "source address (s=%s,d=%s)\n",st->name,client->name,s,d);
-	    free(s); free(d);
+		    "source address (s=%s,d=%s)\n",st->name,sender->name,s,d);
 	    BUF_FREE(buf);
 	    return;
 	}
@@ -863,7 +909,6 @@ static void netlink_incoming(struct netlink *st, struct netlink_client *client,
 	    d=ipaddr_to_string(dest);
 	    Message(M_WARNING,"%s: outgoing packet with bad source address "
 		    "(s=%s,d=%s)\n",st->name,s,d);
-	    free(s); free(d);
 	    BUF_FREE(buf);
 	    return;
 	}
@@ -875,8 +920,8 @@ static void netlink_incoming(struct netlink *st, struct netlink_client *client,
        where it came from.  It's up to external software to check
        address validity and generate ICMP, etc. */
     if (st->ptp) {
-	if (client) {
-	    netlink_host_deliver(st,source,dest,buf);
+	if (sender) {
+	    netlink_host_deliver(st,sender,source,dest,buf);
 	} else {
 	    netlink_client_deliver(st,st->clients,source,dest,buf);
 	}
@@ -887,11 +932,11 @@ static void netlink_incoming(struct netlink *st, struct netlink_client *client,
     /* st->secnet_address needs checking before matching destination
        addresses */
     if (dest==st->secnet_address) {
-	netlink_packet_local(st,client,buf);
+	netlink_packet_local(st,sender,buf);
 	BUF_ASSERT_FREE(buf);
 	return;
     }
-    netlink_packet_forward(st,client,buf);
+    netlink_packet_forward(st,sender,buf);
     BUF_ASSERT_FREE(buf);
 }
 
@@ -931,7 +976,6 @@ static void netlink_output_subnets(struct netlink *st, uint32_t loglevel,
     for (i=0; i<snets->entries; i++) {
 	net=subnet_to_string(snets->list[i]);
 	Message(loglevel,"%s ",net);
-	free(net);
     }
 }
 
@@ -946,7 +990,6 @@ static void netlink_dump_routes(struct netlink *st, bool_t requested)
 	net=ipaddr_to_string(st->secnet_address);
 	Message(c,"%s: point-to-point (remote end is %s); routes: ",
 		st->name, net);
-	free(net);
 	netlink_output_subnets(st,c,st->clients->subnets);
 	Message(c,"\n");
     } else {
@@ -967,11 +1010,9 @@ static void netlink_dump_routes(struct netlink *st, bool_t requested)
 	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);
@@ -1028,12 +1069,16 @@ static void netlink_inst_set_mtu(void *sst, int32_t new_mtu)
 }
 
 static void netlink_inst_reg(void *sst, netlink_deliver_fn *deliver, 
-			     void *dst)
+			     void *dst, uint32_t *localmtu_r)
 {
     struct netlink_client *c=sst;
+    struct netlink *st=c->nst;
 
     c->deliver=deliver;
     c->dst=dst;
+
+    if (localmtu_r)
+	*localmtu_r=st->mtu;
 }
 
 static struct flagstr netlink_option_table[]={
@@ -1186,6 +1231,8 @@ netlink_deliver_fn *netlink_init(struct netlink *st,
 	st->remote_networks=ipset_complement(empty);
 	ipset_free(empty);
     }
+    st->local_address=string_item_to_ipaddr(
+	dict_find_item(dict,"local-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);