net/iptables: check iptables command has wait option

v2: fix compilation warning for snprintf
v3: check iptables has xtables locks support once on init
v4: switch opts to kdat
Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

criu/include/kerndat.h

@@ -34,6 +34,7 @@ struct kerndat_s {
 	bool ipv6;
 	bool has_loginuid;
 	enum pagemap_func pmap;
+	unsigned int has_xtlocks;
 };
 
 extern struct kerndat_s kdat;

criu/kerndat.c

@@ -446,6 +446,17 @@ int kerndat_loginuid(bool only_dump)
 	return 0;
 }
 
+static int kerndat_iptables_has_xtlocks(void)
+{
+	char *argv[4] = { "sh", "-c", "iptables -w -L", NULL };
+
+	kdat.has_xtlocks = 1;
+	if (cr_system(-1, -1, -1, "sh", argv, CRS_CAN_FAIL) == -1)
+		kdat.has_xtlocks = 0;
+
+	return 0;
+}
+
 int kerndat_init(void)
 {
 	int ret;
@@ -467,6 +478,8 @@ int kerndat_init(void)
 		ret = get_ipv6();
 	if (!ret)
 		ret = kerndat_loginuid(true);
+	if (!ret)
+		ret = kerndat_iptables_has_xtlocks();
 
 	kerndat_lsm();
 
@@ -494,6 +507,8 @@ int kerndat_init_rst(void)
 		ret = get_ipv6();
 	if (!ret)
 		ret = kerndat_loginuid(false);
+	if (!ret)
+		ret = kerndat_iptables_has_xtlocks();
 
 	kerndat_lsm();
 

criu/netfilter.c

@@ -12,6 +12,7 @@
 #include "netfilter.h"
 #include "sockets.h"
 #include "sk-inet.h"
+#include "kerndat.h"
 
 static char buf[512];
 
@@ -20,7 +21,7 @@ static char buf[512];
  * ANy brave soul to write it using xtables-devel?
  */
 
-static const char *nf_conn_cmd = "%s -w -t filter %s %s --protocol tcp "
+static const char *nf_conn_cmd = "%s %s -t filter %s %s --protocol tcp "
 	"--source %s --sport %d --destination %s --dport %d -j DROP";
 
 static char iptable_cmd_ipv4[] = "iptables";
@@ -73,6 +74,7 @@ static int nf_connection_switch_raw(int family, u32 *src_addr, u16 src_port,
 	}
 
 	snprintf(buf, sizeof(buf), nf_conn_cmd, cmd,
+			kdat.has_xtlocks ? "-w" : "",
 			lock ? "-A" : "-D",
 			input ? "INPUT" : "OUTPUT",
 			dip, (int)dst_port, sip, (int)src_port);