xfrm: Use the XFRM_GRO to indicate a GRO call on input

This is needed to support GRO for ESP in UDP encapsulation.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Co-developed-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Reviewed-by: Eyal Birger <eyal.birger@gmail.com>

net/ipv4/esp4_offload.c

@@ -77,7 +77,7 @@ static struct sk_buff *esp4_gro_receive(struct list_head *head,
 
 	/* We don't need to handle errors from xfrm_input, it does all
 	 * the error handling and frees the resources on error. */
-	xfrm_input(skb, IPPROTO_ESP, spi, -2);
+	xfrm_input(skb, IPPROTO_ESP, spi, 0);
 
 	return ERR_PTR(-EINPROGRESS);
 out_reset:

net/ipv6/esp6_offload.c

@@ -104,7 +104,7 @@ static struct sk_buff *esp6_gro_receive(struct list_head *head,
 
 	/* We don't need to handle errors from xfrm_input, it does all
 	 * the error handling and frees the resources on error. */
-	xfrm_input(skb, IPPROTO_ESP, spi, -2);
+	xfrm_input(skb, IPPROTO_ESP, spi, 0);
 
 	return ERR_PTR(-EINPROGRESS);
 out_reset:

net/xfrm/xfrm_input.c

@@ -462,7 +462,7 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 	struct xfrm_offload *xo = xfrm_offload(skb);
 	struct sec_path *sp;
 
-	if (encap_type < 0) {
+	if (encap_type < 0 || (xo && xo->flags & XFRM_GRO)) {
 		x = xfrm_input_state(skb);
 
 		if (unlikely(x->km.state != XFRM_STATE_VALID)) {
@@ -485,9 +485,7 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 			seq = XFRM_SKB_CB(skb)->seq.input.low;
 			goto resume;
 		}
-
-		/* encap_type < -1 indicates a GRO call. */
-		encap_type = 0;
+		/* GRO call */
 		seq = XFRM_SPI_SKB_CB(skb)->seq;
 
 		if (xo && (xo->flags & CRYPTO_DONE)) {