From: Michał Kępień <michal@isc.org>
Date: Tue, 8 Jan 2019 10:17:39 +0000 (+0100)
Subject: Remove dead code handling address family mismatches for TCP sockets
X-Git-Tag: v9.13.6~71^2~3
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=ef1da8731b7b176179ba5ca09ae884a524aadc98;p=thirdparty%2Fbind9.git

Remove dead code handling address family mismatches for TCP sockets

Before commit c2ec022f5784a2ff844f7d062c2022197dc4ad09, using the "-b"
command line switch for dig did not disable use of the other address
family than the one to which the address supplied to that option
belonged to.  Thus, bind9_getaddresses() could e.g. prepare an
isc_sockaddr_t structure for an IPv6 address when an IPv4 address has
been passed to the "-b" command line option.  To avoid attempting the
impossible (e.g. querying an IPv6 address from a socket bound to an IPv4
address), a certain code block in send_tcp_connect() checked whether the
address family of the server to be queried was the same as the address
family of the socket set up for sending that query; if there was a
mismatch, that particular server address was skipped.

Commit c2ec022f5784a2ff844f7d062c2022197dc4ad09 made
bind9_getaddresses() fail upon an address family mismatch between the
address the hostname passed to it resolved to and the address supplied
to the "-b" command line option.  Such failures were fatal to dig back
then.

Commit 7f658603910358db7ee27ffb9783096250afab62 made
bind9_getaddresses() failures non-fatal, but also ensured that a
get_address() failure in send_tcp_connect() still causes the given query
address to be skipped (and also made such failures trigger an early
return from send_tcp_connect()).

Summing up, the code block handling address family mismatches in
send_tcp_connect() has been redundant since commit
c2ec022f5784a2ff844f7d062c2022197dc4ad09.  Remove it.
---

diff --git a/bin/dig/dighost.c b/bin/dig/dighost.c
index 2b6cab552e8..400fcaf34fe 100644
--- a/bin/dig/dighost.c
+++ b/bin/dig/dighost.c
@@ -2730,27 +2730,6 @@ send_tcp_connect(dig_query_t *query) {
 		return;
 	}
 
-	if (specified_source &&
-	    (isc_sockaddr_pf(&query->sockaddr) !=
-	     isc_sockaddr_pf(&bind_address))) {
-		printf(";; Skipping server %s, incompatible "
-		       "address family\n", query->servname);
-		query->waiting_connect = false;
-		if (ISC_LINK_LINKED(query, link))
-			next = ISC_LIST_NEXT(query, link);
-		else
-			next = NULL;
-		l = query->lookup;
-		clear_query(query);
-		if (next == NULL) {
-			printf(";; No acceptable nameservers\n");
-			check_next_lookup(l);
-			return;
-		}
-		send_tcp_connect(next);
-		return;
-	}
-
 	INSIST(query->sock == NULL);
 
 	if (keep != NULL && isc_sockaddr_equal(&keepaddr, &query->sockaddr)) {