From 09d60499af3acef2ba9bd7be15e8d1c44249f8d5 Mon Sep 17 00:00:00 2001
From: Guus Sliepen <guus@tinc-vpn.org>
Date: Mon, 9 Feb 2015 15:06:12 +0100
Subject: [PATCH] Always call res_init() before getaddrinfo().

Unfortunately, glibc assumes that /etc/resolv.conf is a static file that
never changes. Even on servers, /etc/resolv.conf might be a dynamically
generated file, and we never know when it changes. So just call
res_init() every time, so glibc uses up-to-date nameserver information.
---
 src/have.h      | 11 +++++++++++
 src/net.c       | 11 -----------
 src/net_setup.c |  4 ++++
 src/netutl.c    |  4 ++++
 4 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/src/have.h b/src/have.h
index bcd46127..e83f98f4 100644
--- a/src/have.h
+++ b/src/have.h
@@ -196,4 +196,15 @@
 #include <netinet/if_ether.h>
 #endif
 
+#ifdef HAVE_ARPA_NAMESER_H
+#include <arpa/nameser.h>
+#ifdef STATUS
+#undef STATUS
+#endif
+#endif
+
+#ifdef HAVE_RESOLV_H
+#include <resolv.h>
+#endif
+
 #endif /* __TINC_SYSTEM_H__ */
diff --git a/src/net.c b/src/net.c
index 8d0a0cf4..08f0a874 100644
--- a/src/net.c
+++ b/src/net.c
@@ -41,14 +41,6 @@
 #include "subnet.h"
 #include "xalloc.h"
 
-#ifdef HAVE_ARPA_NAMESER_H
-#include <arpa/nameser.h>
-#endif
-
-#ifdef HAVE_RESOLV_H
-#include <resolv.h>
-#endif
-
 bool do_purge = false;
 volatile bool running = false;
 #ifdef HAVE_PSELECT
@@ -508,9 +500,6 @@ int main_loop(void) {
 			avl_node_t *node;
 			logger(LOG_INFO, "Flushing event queue");
 			expire_events();
-#if HAVE_DECL_RES_INIT
-			res_init();
-#endif
 			for(node = connection_tree->head; node; node = node->next) {
 				connection_t *c = node->data;
 				if(c->status.active)
diff --git a/src/net_setup.c b/src/net_setup.c
index 765a9ebf..121b9892 100644
--- a/src/net_setup.c
+++ b/src/net_setup.c
@@ -813,6 +813,10 @@ static bool setup_myself(void) {
 			hint.ai_protocol = IPPROTO_TCP;
 			hint.ai_flags = AI_PASSIVE;
 
+#ifdef HAVE_DECL_RES_INIT
+			// ensure glibc reloads /etc/resolv.conf.
+			res_init();
+#endif
 			err = getaddrinfo(address && *address ? address : NULL, port, &hint, &ai);
 			free(address);
 
diff --git a/src/netutl.c b/src/netutl.c
index c57b24ff..fc3cdc91 100644
--- a/src/netutl.c
+++ b/src/netutl.c
@@ -39,6 +39,10 @@ struct addrinfo *str2addrinfo(const char *address, const char *service, int sock
 	hint.ai_family = addressfamily;
 	hint.ai_socktype = socktype;
 
+#ifdef HAVE_DECL_RES_INIT
+	// ensure glibc reloads /etc/resolv.conf.
+	res_init();
+#endif
 	err = getaddrinfo(address, service, &hint, &ai);
 
 	if(err) {
-- 
2.20.1