[IPV6]: Fix IPV6_RECVERR for connected raw sockets.

Based on patch from Dmitry Butskoy <buc@odusz.so-cdu.ru>.

Closes: 10437
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

net/ipv6/raw.c

@@ -357,8 +357,10 @@ void raw6_icmp_error(struct sk_buff *skb, int nexthdr,
 	read_lock(&raw_v6_hashinfo.lock);
 	sk = sk_head(&raw_v6_hashinfo.ht[hash]);
 	if (sk != NULL) {
-		saddr = &ipv6_hdr(skb)->saddr;
-		daddr = &ipv6_hdr(skb)->daddr;
+		/* Note: ipv6_hdr(skb) != skb->data */
+		struct ipv6hdr *ip6h = (struct ipv6hdr *)skb->data;
+		saddr = &ip6h->saddr;
+		daddr = &ip6h->daddr;
 		net = dev_net(skb->dev);
 
 		while ((sk = __raw_v6_lookup(net, sk, nexthdr, saddr, daddr,