nft: fix inversion of built-in selectors

(0ab045f xtables: fix missing ipt_entry for MASQUERADE target) broke
inversion of built-in selectors, such as -s, -d, etc.

We need to refresh the invflags if -p is used or set it for first
time if -p is not used, otherwise inversion is ignored.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/iptables/nft-ipv4.c b/iptables/nft-ipv4.c
index 2ac823f..1afe8b6 100644
--- a/iptables/nft-ipv4.c
+++ b/iptables/nft-ipv4.c
@@ -343,6 +343,10 @@
 				struct xtables_args *args)
 {
 	cs->fw.ip.flags = args->flags;
+	/* We already set invflags in proto_parse, but we need to refresh it
+	 * to include new parsed options.
+	 */
+	cs->fw.ip.invflags = args->invflags;
 
 	strncpy(cs->fw.ip.iniface, args->iniface, IFNAMSIZ);
 	memcpy(cs->fw.ip.iniface_mask,
diff --git a/iptables/nft-ipv6.c b/iptables/nft-ipv6.c
index b02d952..f30cec6 100644
--- a/iptables/nft-ipv6.c
+++ b/iptables/nft-ipv6.c
@@ -264,6 +264,10 @@
 		args->flags |= IP6T_F_PROTO;
 
 	cs->fw6.ipv6.flags = args->flags;
+	/* We already set invflags in proto_parse, but we need to refresh it
+	 * to include new parsed options.
+	 */
+	cs->fw6.ipv6.invflags = args->invflags;
 
 	strncpy(cs->fw6.ipv6.iniface, args->iniface, IFNAMSIZ);
 	memcpy(cs->fw6.ipv6.iniface_mask,