BUG/MINOR: Fix name lookup ordering when compiled with USE_GETADDRINFO

When compiled with USE_GETADDRINFO, make sure we use getaddrinfo(3) to
perform name lookups. On default dual-stack setups this will change the
behavior of using IPv6 first. Global configuration option
'nogetaddrinfo' can be used to revert to deprecated gethostbyname(3).

include/types/global.h

@@ -57,6 +57,7 @@
 #define GTUNE_USE_KQUEUE         (1<<3)
 /* platform-specific options */
 #define GTUNE_USE_SPLICE         (1<<4)
+#define GTUNE_USE_GAI            (1<<5)
 
 /* Access level for a stats socket */
 #define ACCESS_LVL_NONE     0

src/cfgparse.c

@@ -506,6 +506,9 @@ int cfg_parse_global(const char *file, int linenum, char **args, int kwm)
 	else if (!strcmp(args[0], "nosplice")) {
 		global.tune.options &= ~GTUNE_USE_SPLICE;
 	}
+	else if (!strcmp(args[0], "nogetaddrinfo")) {
+		global.tune.options &= ~GTUNE_USE_GAI;
+	}
 	else if (!strcmp(args[0], "quiet")) {
 		global.mode |= MODE_QUIET;
 	}

src/haproxy.c

@@ -384,6 +384,9 @@ void usage(char *name)
 #endif
 #if defined(CONFIG_HAP_LINUX_SPLICE)
 		"        -dS disables splice usage (broken on old kernels)\n"
+#endif
+#if defined(USE_GETADDRINFO)
+		"        -dG disables getaddrinfo() usage\n"
 #endif
 		"        -dV disables SSL verify on servers side\n"
 		"        -sf/-st [pid ]* finishes/terminates old pids. Must be last arguments.\n"
@@ -553,6 +556,9 @@ void init(int argc, char **argv)
 #if defined(CONFIG_HAP_LINUX_SPLICE)
 	global.tune.options |= GTUNE_USE_SPLICE;
 #endif
+#if defined(USE_GETADDRINFO)
+	global.tune.options |= GTUNE_USE_GAI;
+#endif
 
 	pid = getpid();
 	progname = *argv;
@@ -591,6 +597,10 @@ void init(int argc, char **argv)
 #if defined(CONFIG_HAP_LINUX_SPLICE)
 			else if (*flag == 'd' && flag[1] == 'S')
 				global.tune.options &= ~GTUNE_USE_SPLICE;
+#endif
+#if defined(USE_GETADDRINFO)
+			else if (*flag == 'd' && flag[1] == 'G')
+				global.tune.options &= ~GTUNE_USE_GAI;
 #endif
 			else if (*flag == 'd' && flag[1] == 'V')
 				global.ssl_server_verify = SSL_SERVER_VERIFY_NONE;

src/standard.c

@@ -552,25 +552,8 @@ static struct sockaddr_storage *str2ip(const char *str, struct sockaddr_storage
 		return sa;
 	}
 
-	/* try to resolve an IPv4/IPv6 hostname */
-	he = gethostbyname(str);
-	if (he) {
-		if (!sa->ss_family || sa->ss_family == AF_UNSPEC)
-			sa->ss_family = he->h_addrtype;
-		else if (sa->ss_family != he->h_addrtype)
-			goto fail;
-
-		switch (sa->ss_family) {
-		case AF_INET:
-			((struct sockaddr_in *)sa)->sin_addr = *(struct in_addr *) *(he->h_addr_list);
-			return sa;
-		case AF_INET6:
-			((struct sockaddr_in6 *)sa)->sin6_addr = *(struct in6_addr *) *(he->h_addr_list);
-			return sa;
-		}
-	}
 #ifdef USE_GETADDRINFO
-	else {
+	if (global.tune.options & GTUNE_USE_GAI) {
 		struct addrinfo hints, *result;
 
 		memset(&result, 0, sizeof(result));
@@ -600,6 +583,24 @@ static struct sockaddr_storage *str2ip(const char *str, struct sockaddr_storage
 			freeaddrinfo(result);
 	}
 #endif
+	/* try to resolve an IPv4/IPv6 hostname */
+	he = gethostbyname(str);
+	if (he) {
+		if (!sa->ss_family || sa->ss_family == AF_UNSPEC)
+			sa->ss_family = he->h_addrtype;
+		else if (sa->ss_family != he->h_addrtype)
+			goto fail;
+
+		switch (sa->ss_family) {
+		case AF_INET:
+			((struct sockaddr_in *)sa)->sin_addr = *(struct in_addr *) *(he->h_addr_list);
+			return sa;
+		case AF_INET6:
+			((struct sockaddr_in6 *)sa)->sin6_addr = *(struct in6_addr *) *(he->h_addr_list);
+			return sa;
+		}
+	}
+
 	/* unsupported address family */
  fail:
 	return NULL;