- Set SO_REUSEADDR on outgoing tcp connections to fix the bind before

connect limited tcp connections.  With the option tcp connections
  can share the same source port (for different destinations).


git-svn-id: file:///svn/unbound/trunk@4151 be551aaa-1e26-0410-a405-d3ace91eadb9

doc/Changelog

@@ -1,5 +1,8 @@
 8 May 2017: Wouter
 	- Fix tcp-mss failure printout text.
+	- Set SO_REUSEADDR on outgoing tcp connections to fix the bind before
+	  connect limited tcp connections.  With the option tcp connections
+	  can share the same source port (for different destinations).
 
 2 May 2017: Ralph
 	- Added mesh_add_sub to add detached mesh entries.

services/outside_network.c

@@ -204,6 +204,9 @@ outnet_tcp_take_into_use(struct waiting_tcp* w, uint8_t* pkt, size_t pkt_len)
 {
 	struct pending_tcp* pend = w->outnet->tcp_free;
 	int s;
+#ifdef SO_REUSEADDR
+	int on = 1;
+#endif
 	log_assert(pend);
 	log_assert(pkt);
 	log_assert(w->addrlen > 0);
@@ -225,6 +228,13 @@ outnet_tcp_take_into_use(struct waiting_tcp* w, uint8_t* pkt, size_t pkt_len)
 		return 0;
 	}
 
+#ifdef SO_REUSEADDR
+	if(setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (void*)&on,
+		(socklen_t)sizeof(on)) < 0) {
+		verbose(VERB_ALGO, "outgoing tcp:"
+			" setsockopt(.. SO_REUSEADDR ..) failed");
+	}
+#endif
 	if (w->outnet->tcp_mss > 0) {
 #if defined(IPPROTO_TCP) && defined(TCP_MAXSEG)
 		if(setsockopt(s, IPPROTO_TCP, TCP_MAXSEG,