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

@@ -198,6 +198,18 @@
 #include <netinet/if_ether.h>
 #endif
 
+#ifdef HAVE_ARPA_NAMESER_H
+#include <arpa/nameser.h>
+#endif
+
+#ifdef HAVE_RESOLV_H
+#include <resolv.h>
+#endif
+
+#ifdef STATUS
+#undef STATUS
+#endif
+
 #ifdef HAVE_MINGW
 #define SLASH "\\"
 #else

src/net.c

@@ -36,10 +36,6 @@
 #include "subnet.h"
 #include "xalloc.h"
 
-#ifdef HAVE_RESOLV_H
-#include <resolv.h>
-#endif
-
 int contradicting_add_edge = 0;
 int contradicting_del_edge = 0;
 static int sleeptime = 10;
@@ -313,9 +309,6 @@ static void sighup_handler(void *data) {
 
 static void sigalrm_handler(void *data) {
 	logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(((signal_t *)data)->signum));
-#ifdef HAVE_DECL_RES_INIT
-	res_init();
-#endif
 	retry();
 }
 #endif

src/net_setup.c

@@ -663,6 +663,9 @@ static bool add_listen_address(char *address, bool bindto) {
 	hint.ai_protocol = IPPROTO_TCP;
 	hint.ai_flags = AI_PASSIVE;
 
+#ifdef HAVE_DECL_RES_INIT
+	res_init();
+#endif
 	int err = getaddrinfo(address && *address ? address : NULL, port, &hint, &ai);
 	free(address);
 

src/netutl.c

@@ -39,6 +39,9 @@ struct addrinfo *str2addrinfo(const char *address, const char *service, int sock
 	hint.ai_family = addressfamily;
 	hint.ai_socktype = socktype;
 
+#ifdef HAVE_DECL_RES_INIT
+	res_init();
+#endif
 	err = getaddrinfo(address, service, &hint, &ai);
 
 	if(err) {