[BRIDGE-NF]: Fix bridge-nf ipv6 length check

A typo caused some bridged IPv6 packets to get dropped randomly,
as reported by Sebastien Chaumontet. The patch below fixes this
(using skb->nh.raw instead of raw) and also makes the jumbo packet
length checking up-to-date with the code in
net/ipv6/exthdrs.c::ipv6_hop_jumbo.
Signed-off-by: Bart De Schuymer <bdschuym@pandora.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_netfilter.c

@@ -295,7 +295,7 @@ static int check_hbh_len(struct sk_buff *skb)
 	len -= 2;
 
 	while (len > 0) {
-		int optlen = raw[off+1]+2;
+		int optlen = skb->nh.raw[off+1]+2;
 
 		switch (skb->nh.raw[off]) {
 		case IPV6_TLV_PAD0:
@@ -308,18 +308,15 @@ static int check_hbh_len(struct sk_buff *skb)
 		case IPV6_TLV_JUMBO:
 			if (skb->nh.raw[off+1] != 4 || (off&3) != 2)
 				goto bad;
-
 			pkt_len = ntohl(*(u32*)(skb->nh.raw+off+2));
-
+			if (pkt_len <= IPV6_MAXPLEN ||
+			    skb->nh.ipv6h->payload_len)
+				goto bad;
 			if (pkt_len > skb->len - sizeof(struct ipv6hdr))
 				goto bad;
-			if (pkt_len + sizeof(struct ipv6hdr) < skb->len) {
-				if (__pskb_trim(skb,
-				    pkt_len + sizeof(struct ipv6hdr)))
+			if (pskb_trim_rcsum(skb,
+			    pkt_len+sizeof(struct ipv6hdr)))
 				goto bad;
-				if (skb->ip_summed == CHECKSUM_HW)
-					skb->ip_summed = CHECKSUM_NONE;
-			}
 			break;
 		default:
 			if (optlen > len)