Merge branch 'udp-gro'

Paolo Abeni says:

====================
udp: implement GRO support

This series implements GRO support for UDP sockets, as the RX counterpart
of commit bec1f6f69736 ("udp: generate gso with UDP_SEGMENT").
The core functionality is implemented by the second patch, introducing a new
sockopt to enable UDP_GRO, while patch 3 implements support for passing the
segment size to the user space via a new cmsg.
UDP GRO performs a socket lookup for each ingress packets and aggregate datagram
directed to UDP GRO enabled sockets with constant l4 tuple.

UDP GRO packets can land on non GRO-enabled sockets, e.g. due to iptables NAT
rules, and that could potentially confuse existing applications.

The solution adopted here is to de-segment the GRO packet before enqueuing
as needed. Since we must cope with packet reinsertion after de-segmentation,
the relevant code is factored-out in ipv4 and ipv6 specific helpers and exposed
to UDP usage.

While the current code can probably be improved, this safeguard ,implemented in
the patches 4-7, allows future enachements to enable UDP GSO offload on more
virtual devices eventually even on forwarded packets.

The last 4 for patches implement some performance and functional self-tests,
re-using the existing udpgso infrastructure. The problematic scenario described
above is explicitly tested.

This revision of the series try to address the feedback provided by Willem and
Subash on previous iteration.
====================

Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 24 insertions, 1 deletions

diff --git a/include/linux/udp.h b/include/linux/udp.h
index 320d49d85484..0a9c54e76305 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -49,7 +49,13 @@ struct udp_sock {
 	unsigned int	 corkflag;	/* Cork is required */
 	__u8		 encap_type;	/* Is this an Encapsulation socket? */
 	unsigned char	 no_check6_tx:1,/* Send zero UDP6 checksums on TX? */
-			 no_check6_rx:1;/* Allow zero UDP6 checksums on RX? */
+			 no_check6_rx:1,/* Allow zero UDP6 checksums on RX? */
+			 encap_enabled:1, /* This socket enabled encap
+					   * processing; UDP tunnels and
+					   * different encapsulation layer set
+					   * this
+					   */
+			 gro_enabled:1;	/* Can accept GRO packets */
 	/*
 	 * Following member retains the information to create a UDP header
 	 * when the socket is uncorked.
@@ -115,6 +121,23 @@ static inline bool udp_get_no_check6_rx(struct sock *sk)
 	return udp_sk(sk)->no_check6_rx;
 }
 
+static inline void udp_cmsg_recv(struct msghdr *msg, struct sock *sk,
+				 struct sk_buff *skb)
+{
+	int gso_size;
+
+	if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) {
+		gso_size = skb_shinfo(skb)->gso_size;
+		put_cmsg(msg, SOL_UDP, UDP_GRO, sizeof(gso_size), &gso_size);
+	}
+}
+
+static inline bool udp_unexpected_gso(struct sock *sk, struct sk_buff *skb)
+{
+	return !udp_sk(sk)->gro_enabled && skb_is_gso(skb) &&
+	       skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4;
+}
+
 #define udp_portaddr_for_each_entry(__sk, list) \
 	hlist_for_each_entry(__sk, list, __sk_common.skc_portaddr_node)