netfilter: move br_nf_check_hbh_len to utils

Rename br_nf_check_hbh_len() to nf_ip6_check_hbh_len() and move it
to netfilter utils, so that it can be used by other modules, like
ovs and tc.

Signed-off-by: Xin Long <[e-mail]>
Reviewed-by: Simon Horman <[e-mail]>
Reviewed-by: Nikolay Aleksandrov <[e-mail]>
Reviewed-by: Aaron Conole <[e-mail]>
Signed-off-by: Florian Westphal <[e-mail]>

include/linux/netfilter_ipv6.h

···
 __sum16 nf_ip6_checksum(struct sk_buff *skb, unsigned int hook,
 			unsigned int dataoff, u_int8_t protocol);
 
+int nf_ip6_check_hbh_len(struct sk_buff *skb, u32 *plen);
+
 int ipv6_netfilter_init(void);
 void ipv6_netfilter_fini(void);
 

net/bridge/br_netfilter_ipv6.c

···
 #include <linux/sysctl.h>
 #endif
 
-/* We only check the length. A bridge shouldn't do any hop-by-hop stuff
- * anyway
- */
-static int br_nf_check_hbh_len(struct sk_buff *skb, u32 *plen)
-{
-	int len, off = sizeof(struct ipv6hdr);
-	unsigned char *nh;
-
-	if (!pskb_may_pull(skb, off + 8))
-		return -1;
-	nh = (unsigned char *)(ipv6_hdr(skb) + 1);
-	len = (nh[1] + 1) << 3;
-
-	if (!pskb_may_pull(skb, off + len))
-		return -1;
-	nh = skb_network_header(skb);
-
-	off += 2;
-	len -= 2;
-	while (len > 0) {
-		int optlen;
-
-		if (nh[off] == IPV6_TLV_PAD1) {
-			off++;
-			len--;
-			continue;
-		}
-		if (len < 2)
-			return -1;
-		optlen = nh[off + 1] + 2;
-		if (optlen > len)
-			return -1;
-
-		if (nh[off] == IPV6_TLV_JUMBO) {
-			u32 pkt_len;
-
-			if (nh[off + 1] != 4 || (off & 3) != 2)
-				return -1;
-			pkt_len = ntohl(*(__be32 *)(nh + off + 2));
-			if (pkt_len <= IPV6_MAXPLEN ||
-			    ipv6_hdr(skb)->payload_len)
-				return -1;
-			if (pkt_len > skb->len - sizeof(struct ipv6hdr))
-				return -1;
-			*plen = pkt_len;
-		}
-		off += optlen;
-		len -= optlen;
-	}
-
-	return len ? -1 : 0;
-}
-
 int br_validate_ipv6(struct net *net, struct sk_buff *skb)
 {
 	const struct ipv6hdr *hdr;
···
 		goto inhdr_error;
 
 	pkt_len = ntohs(hdr->payload_len);
-	if (hdr->nexthdr == NEXTHDR_HOP && br_nf_check_hbh_len(skb, &pkt_len))
+	if (hdr->nexthdr == NEXTHDR_HOP && nf_ip6_check_hbh_len(skb, &pkt_len))
 		goto drop;
 
 	if (pkt_len + ip6h_len > skb->len) {

net/netfilter/utils.c

···
 	}
 	return ret;
 }
+
+/* Only get and check the lengths, not do any hop-by-hop stuff. */
+int nf_ip6_check_hbh_len(struct sk_buff *skb, u32 *plen)
+{
+	int len, off = sizeof(struct ipv6hdr);
+	unsigned char *nh;
+
+	if (!pskb_may_pull(skb, off + 8))
+		return -ENOMEM;
+	nh = (unsigned char *)(ipv6_hdr(skb) + 1);
+	len = (nh[1] + 1) << 3;
+
+	if (!pskb_may_pull(skb, off + len))
+		return -ENOMEM;
+	nh = skb_network_header(skb);
+
+	off += 2;
+	len -= 2;
+	while (len > 0) {
+		int optlen;
+
+		if (nh[off] == IPV6_TLV_PAD1) {
+			off++;
+			len--;
+			continue;
+		}
+		if (len < 2)
+			return -EBADMSG;
+		optlen = nh[off + 1] + 2;
+		if (optlen > len)
+			return -EBADMSG;
+
+		if (nh[off] == IPV6_TLV_JUMBO) {
+			u32 pkt_len;
+
+			if (nh[off + 1] != 4 || (off & 3) != 2)
+				return -EBADMSG;
+			pkt_len = ntohl(*(__be32 *)(nh + off + 2));
+			if (pkt_len <= IPV6_MAXPLEN ||
+			    ipv6_hdr(skb)->payload_len)
+				return -EBADMSG;
+			if (pkt_len > skb->len - sizeof(struct ipv6hdr))
+				return -EBADMSG;
+			*plen = pkt_len;
+		}
+		off += optlen;
+		len -= optlen;
+	}
+
+	return len ? -EBADMSG : 0;
+}
+EXPORT_SYMBOL_GPL(nf_ip6_check_hbh_len);