rxrpc: do not pull udp headers on receive

Commit e6afc8ace6dd modified the udp receive path by pulling the udp
header before queuing an skbuff onto the receive queue.

Rxrpc also calls skb_recv_datagram to dequeue an skb from a udp
socket. Modify this receive path to also no longer expect udp
headers.

Fixes: e6afc8ace6dd ("udp: remove headers from UDP packets before queueing")

Signed-off-by: Willem de Bruijn <willemb@google.com>
Tested-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/rxrpc/ar-input.c

@@ -612,9 +612,9 @@ int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
 	struct rxrpc_wire_header whdr;
 
 	/* dig out the RxRPC connection details */
-	if (skb_copy_bits(skb, sizeof(struct udphdr), &whdr, sizeof(whdr)) < 0)
+	if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0)
 		return -EBADMSG;
-	if (!pskb_pull(skb, sizeof(struct udphdr) + sizeof(whdr)))
+	if (!pskb_pull(skb, sizeof(whdr)))
 		BUG();
 
 	memset(sp, 0, sizeof(*sp));