Use strrchr to ensure we split off the last colon for the service port

IPv6 addresses have colons and will produce invalid data for the getaddrinfo lookup.

Signed-off-by: Andrew Thompson <[email protected]>

AUTHORS

@@ -2,6 +2,7 @@ Contributors
 ============
 
 Alexej Lotz <[email protected]>
+Andrew Thompson <[email protected]>
 Asko Kauppi <[email protected]>
 Barak Amar <[email protected]>
 Bernd Prager <[email protected]>

src/ip.cpp

@@ -272,7 +272,7 @@ int zmq::resolve_ip_hostname (sockaddr_storage *addr_, socklen_t *addr_len_,
     const char *hostname_)
 {
     //  Find the ':' that separates hostname name from service.
-    const char *delimiter = strchr (hostname_, ':');
+    const char *delimiter = strrchr (hostname_, ':');
     if (!delimiter) {
         errno = EINVAL;
         return -1;