netfilter: nfnetlink: add nfnetlink_rcv_skb_batch()

Add new nfnetlink_rcv_skb_batch() to wrap initial nfnetlink batch
handling.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nfnetlink.c

@@ -436,24 +436,12 @@ static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh,
 	kfree_skb(skb);
 }
 
-static void nfnetlink_rcv(struct sk_buff *skb)
+static void nfnetlink_rcv_skb_batch(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
-	struct nlmsghdr *nlh = nlmsg_hdr(skb);
+	struct nfgenmsg *nfgenmsg;
 	u16 res_id;
 	int msglen;
 
-	if (nlh->nlmsg_len < NLMSG_HDRLEN ||
-	    skb->len < nlh->nlmsg_len)
-		return;
-
-	if (!netlink_net_capable(skb, CAP_NET_ADMIN)) {
-		netlink_ack(skb, nlh, -EPERM);
-		return;
-	}
-
-	if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN) {
-		struct nfgenmsg *nfgenmsg;
-
 	msglen = NLMSG_ALIGN(nlh->nlmsg_len);
 	if (msglen > skb->len)
 		msglen = skb->len;
@@ -469,10 +457,27 @@ static void nfnetlink_rcv(struct sk_buff *skb)
 		res_id = NFNL_SUBSYS_NFTABLES;
 	else
 		res_id = ntohs(nfgenmsg->res_id);
+
 	nfnetlink_rcv_batch(skb, nlh, res_id);
-	} else {
-		netlink_rcv_skb(skb, &nfnetlink_rcv_msg);
+}
+
+static void nfnetlink_rcv(struct sk_buff *skb)
+{
+	struct nlmsghdr *nlh = nlmsg_hdr(skb);
+
+	if (nlh->nlmsg_len < NLMSG_HDRLEN ||
+	    skb->len < nlh->nlmsg_len)
+		return;
+
+	if (!netlink_net_capable(skb, CAP_NET_ADMIN)) {
+		netlink_ack(skb, nlh, -EPERM);
+		return;
 	}
+
+	if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN)
+		nfnetlink_rcv_skb_batch(skb, nlh);
+	else
+		netlink_rcv_skb(skb, &nfnetlink_rcv_msg);
 }
 
 #ifdef CONFIG_MODULES