+ /* If the host is the same, we're in business. If not, there is
+ still hope -- read below. */
+ if (0 != strcasecmp (host, pconn.host))
+ {
+ /* If pconn.socket is already talking to HOST, we needn't
+ reconnect. This happens often when both sites are virtual
+ hosts distinguished only by name and served by the same
+ network interface, and hence the same web server (possibly
+ set up by the ISP and serving many different web sites).
+ This admittedly non-standard optimization does not contradict
+ HTTP and works well with popular server software. */
+
+ int found;
+ ip_address ip;
+ struct address_list *al;
+
+ if (ssl)
+ /* Don't try to talk to two different SSL sites over the same
+ secure connection! (Besides, it's not clear if name-based
+ virtual hosting is even possible with SSL.) */
+ return 0;
+
+ /* If pconn.socket's peer is one of the IP addresses HOST
+ resolves to, pconn.socket is for all intents and purposes
+ already talking to HOST. */
+
+ if (!socket_ip_address (pconn.socket, &ip, ENDPOINT_PEER))
+ {
+ /* Can't get the peer's address -- something must be very
+ wrong with the connection. */
+ invalidate_persistent ();
+ return 0;
+ }
+ al = lookup_host (host, 0);
+ if (!al)
+ {
+ *host_lookup_failed = 1;
+ return 0;
+ }
+
+ found = address_list_contains (al, &ip);
+ address_list_release (al);
+
+ if (!found)
+ return 0;
+
+ /* The persistent connection's peer address was found among the
+ addresses HOST resolved to; therefore, pconn.sock is in fact
+ already talking to HOST -- no need to reconnect. */
+ }