When packets hit raw sockets the csum update isn't done yet, do it manually.
Packets can also reach rawv6_rcv on the output path through
ip6_call_ra_chain, in this case skb->ip_summed is CHECKSUM_NONE and this
codepath isn't executed.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
 
        if (skb->ip_summed != CHECKSUM_UNNECESSARY) {
                if (skb->ip_summed == CHECKSUM_HW) {
+                       skb_postpull_rcsum(skb, skb->nh.raw,
+                                          skb->h.raw - skb->nh.raw);
                        skb->ip_summed = CHECKSUM_UNNECESSARY;
                        if (csum_ipv6_magic(&skb->nh.ipv6h->saddr,
                                            &skb->nh.ipv6h->daddr,