Re: [PATCH RFC ipsec-next 5/5] esp: Add a software GRO codepath

On Tue, 2017-02-07 at 10:14 +0100, Steffen Klassert wrote:

This patch adds GRO ifrastructure and callbacks for ESP on
ipv4 and ipv6.

I am a bit confused.

 
-struct xfrm_tunnel_skb_cb {
+/*
+ * This structure is used if we get the packet from the gro layer.
+ */
+struct xfrm_gro_skb_cb {
 	union {
 		struct inet_skb_parm h4;
 		struct inet6_skb_parm h6;
-	} header;
+
+		struct {
+			__be32 seq;
+			bool skb_is_gro;
+		} input;
+	} gro;
+};
+
+#define XFRM_GRO_SKB_CB(__skb) ((struct xfrm_gro_skb_cb *)&((__skb)->cb[0]))
+

Then :

+
+	x = xfrm_state_lookup(dev_net(skb->dev), skb->mark,
+			      (xfrm_address_t *)&ip_hdr(skb)->daddr,
+			      spi, IPPROTO_ESP, AF_INET);
+	if (!x)
+		goto out;
+
+	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
+	XFRM_SPI_SKB_CB(skb)->family = AF_INET;
+	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
+	XFRM_GRO_SKB_CB(skb)->gro.input.seq = seq;
+	skb->sp->xvec[skb->sp->len++] = x;
+
+	/* 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);
+
+	return ERR_PTR(-EINPROGRESS);
+out:
+	skb_push(skb, offset);
+	NAPI_GRO_CB(skb)->same_flow = 0;
+	NAPI_GRO_CB(skb)->flush = 1;
+

How can you mix XFRM_SPI_SKB_CB(), XFRM_GRO_SKB_CB() and NAPI_GRO_CB()
at the same time on one skb ?