[PATCH v2 net-next 0/5] udp: Generalize GSO for UDP tunnels

[PATCH v2 net-next 0/5] udp: Generalize GSO for UDP tunnels

[Tom Herbert]

This patch set generalizes the UDP tunnel segmentation functions so
that they can work with various protocol encapsulations. The primary
change is to set the inner_protocol field in the skbuff when creating
the encapsulated packet, and then in skb_udp_tunnel_segment this data
is used to determine the function for segmenting the encapsulated
packet. The inner_protocol field is overloaded to take either an
Ethertype or IP protocol.

The inner_protocol is set on transmit using skb_set_inner_ipproto or
skb_set_inner_protocol functions. VXLAN and IP tunnels (for fou GSO)
were modified to call these.

Notes:
  - GSO for GRE/UDP where GRE checksum is enabled does not work.
    Handling this will require some special case code.
  - Software GSO now supports many varieties of encapsulation with
    SKB_GSO_UDP_TUNNEL{_CSUM}. We still need a mechanism to query
    for device support of particular combinations (I intend to
    add ndo_gso_check for that).
  - MPLS seems to be the only previous user of inner_protocol. I don't
    believe these patches can affect that. For supporting GSO with
    MPLS over UDP, the inner_protocol should be set using the
    helper functions in this patch.
  - GSO for L2TP/UDP should also be straightforward now.

v2:
  - Respin for Eric's restructuring of skbuff.

Tested GRE, IPIP, and SIT over fou as well as VLXAN. This was
done using 200 TCP_STREAMs in netperf.

 GRE
    IPv4, FOU, UDP checksum enabled
      TCP_STREAM TSO enabled on tun interface
        14.04% TX CPU utilization
        13.17% RX CPU utilization
        9211 Mbps
      TCP_STREAM TSO disabled on tun interface
        27.82% TX CPU utilization
        25.41% RX CPU utilization
        9336 Mbps
    IPv4, FOU, UDP checksum disabled
      TCP_STREAM TSO enabled on tun interface
        13.14% TX CPU utilization
        23.18% RX CPU utilization
        9277 Mbps
      TCP_STREAM TSO disabled on tun interface
        30.00% TX CPU utilization
        31.28% RX CPU utilization
        9327 Mbps

  IPIP
    FOU, UDP checksum enabled
      TCP_STREAM TSO enabled on tun interface
        15.28% TX CPU utilization
        13.92% RX CPU utilization
        9342 Mbps
      TCP_STREAM TSO disabled on tun interface
        27.82% TX CPU utilization
        25.41% RX CPU utilization
        9336 Mbps
    FOU, UDP checksum disabled
      TCP_STREAM TSO enabled on tun interface
        15.08% TX CPU utilization
        24.64% RX CPU utilization
        9226 Mbps
      TCP_STREAM TSO disabled on tun interface
        30.00% TX CPU utilization
        31.28% RX CPU utilization
        9327 Mbps

  SIT
    FOU, UDP checksum enabled
      TCP_STREAM TSO enabled on tun interface
        14.47% TX CPU utilization
        14.58% RX CPU utilization
        9106 Mbps
      TCP_STREAM TSO disabled on tun interface
        31.82% TX CPU utilization
        30.82% RX CPU utilization
        9204 Mbps
    FOU, UDP checksum disabled
      TCP_STREAM TSO enabled on tun interface
        15.70% TX CPU utilization
        27.93% RX CPU utilization
        9097 Mbps
      TCP_STREAM TSO disabled on tun interface
        33.48% TX CPU utilization
        37.36% RX CPU utilization
        9197 Mbps

   VXLAN
      TCP_STREAM TSO enabled on tun interface
        16.42% TX CPU utilization
        23.66% RX CPU utilization
        9081 Mbps
      TCP_STREAM TSO disabled on tun interface
        30.32% TX CPU utilization
        30.55% RX CPU utilization
        9185 Mbps

   Baseline (no encp, TSO and LRO enabled)
      TCP_STREAM
        11.85% TX CPU utilization
        15.13% RX CPU utilization
        9452 Mbps

Tom Herbert (5):
  udp: Generalize skb_udp_segment
  sit: Set inner IP protocol in sit
  ipip: Set inner IP protocol in ipip
  gre: Set inner protocol in v4 and v6 GRE transmit
  vxlan: Set inner protocol before transmit

 drivers/net/vxlan.c    |  4 ++++
 include/linux/skbuff.h | 26 +++++++++++++++++++++++--
 include/net/udp.h      |  3 ++-
 net/ipv4/ip_gre.c      |  2 ++
 net/ipv4/ipip.c        |  2 ++
 net/ipv4/udp_offload.c | 51 +++++++++++++++++++++++++++++++++++++++++++++-----
 net/ipv6/ip6_gre.c     |  8 ++++++--
 net/ipv6/sit.c         |  4 ++++
 net/ipv6/udp_offload.c |  2 +-
 9 files changed, 91 insertions(+), 11 deletions(-)

-- 
2.1.0.rc2.206.gedb03e5

[PATCH v2 net-next 1/5] udp: Generalize skb_udp_segment

[Tom Herbert]

skb_udp_segment is the function called from udp4_ufo_fragment to
segment a UDP tunnel packet. This function currently assumes
segmentation is transparent Ethernet bridging (i.e. VXLAN
encapsulation). This patch generalizes the function to
operate on either Ethertype or IP protocol.

The inner_protocol field must be set to the protocol of the inner
header. This can now be either an Ethertype or an IP protocol
(in a union). A new flag in the skbuff indicates which type is
effective. skb_set_inner_protocol and skb_set_inner_ipproto
helper functions were added to set the inner_protocol. These
functions are called from the point where the tunnel encapsulation
is occuring.

When skb_udp_tunnel_segment is called, the function to segment the
inner packet is selected based on the inner IP or Ethertype. In the
case of an IP protocol encapsulation, the function is derived from
inet[6]_offloads. In the case of Ethertype, skb->protocol is
set to the inner_protocol and skb_mac_gso_segment is called. (GRE
currently does this, but it might be possible to lookup the protocol
in offload_base and call the appropriate segmenation function
directly).

Signed-off-by: Tom Herbert <therbert@google.com>
---
 include/linux/skbuff.h | 26 +++++++++++++++++++++++--
 include/net/udp.h      |  3 ++-
 net/ipv4/udp_offload.c | 51 +++++++++++++++++++++++++++++++++++++++++++++-----
 net/ipv6/udp_offload.c |  2 +-
 4 files changed, 73 insertions(+), 9 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 262efdb..49bc464 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -596,7 +596,8 @@ struct sk_buff {
 	__u8			ndisc_nodetype:2;
 #endif
 	__u8			ipvs_property:1;
-	/* 5 or 7 bit hole */
+	__u8			inner_protocol_type:1;
+	/* 4 or 6 bit hole */
 
 #ifdef CONFIG_NET_SCHED
 	__u16			tc_index;	/* traffic control index */
@@ -632,7 +633,11 @@ struct sk_buff {
 		__u32		reserved_tailroom;
 	};
 
-	__be16			inner_protocol;
+	union {
+		__be16		inner_protocol;
+		__u8		inner_ipproto;
+	};
+
 	__u16			inner_transport_header;
 	__u16			inner_network_header;
 	__u16			inner_mac_header;
@@ -1737,6 +1742,23 @@ static inline void skb_reserve(struct sk_buff *skb, int len)
 	skb->tail += len;
 }
 
+#define ENCAP_TYPE_ETHER	0
+#define ENCAP_TYPE_IPPROTO	1
+
+static inline void skb_set_inner_protocol(struct sk_buff *skb,
+					  __be16 protocol)
+{
+	skb->inner_protocol = protocol;
+	skb->inner_protocol_type = ENCAP_TYPE_ETHER;
+}
+
+static inline void skb_set_inner_ipproto(struct sk_buff *skb,
+					 __u8 ipproto)
+{
+	skb->inner_ipproto = ipproto;
+	skb->inner_protocol_type = ENCAP_TYPE_IPPROTO;
+}
+
 static inline void skb_reset_inner_headers(struct sk_buff *skb)
 {
 	skb->inner_mac_header = skb->mac_header;
diff --git a/include/net/udp.h b/include/net/udp.h
index 16f4e80..07f9b70 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -239,7 +239,8 @@ int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
 int udp_disconnect(struct sock *sk, int flags);
 unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait);
 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
-				       netdev_features_t features);
+				       netdev_features_t features,
+				       bool is_ipv6);
 int udp_lib_getsockopt(struct sock *sk, int level, int optname,
 		       char __user *optval, int __user *optlen);
 int udp_lib_setsockopt(struct sock *sk, int level, int optname,
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index 19ebe6a..8c35f2c 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -25,8 +25,11 @@ struct udp_offload_priv {
 	struct udp_offload_priv __rcu *next;
 };
 
-struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
-				       netdev_features_t features)
+static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
+	netdev_features_t features,
+	struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
+					     netdev_features_t features),
+	__be16 new_protocol)
 {
 	struct sk_buff *segs = ERR_PTR(-EINVAL);
 	u16 mac_offset = skb->mac_header;
@@ -48,7 +51,7 @@ struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
 	skb_reset_mac_header(skb);
 	skb_set_network_header(skb, skb_inner_network_offset(skb));
 	skb->mac_len = skb_inner_network_offset(skb);
-	skb->protocol = htons(ETH_P_TEB);
+	skb->protocol = new_protocol;
 
 	need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
 	if (need_csum)
@@ -56,7 +59,7 @@ struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
 
 	/* segment inner packet. */
 	enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
-	segs = skb_mac_gso_segment(skb, enc_features);
+	segs = gso_inner_segment(skb, enc_features);
 	if (IS_ERR_OR_NULL(segs)) {
 		skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
 				     mac_len);
@@ -101,6 +104,44 @@ out:
 	return segs;
 }
 
+struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
+				       netdev_features_t features,
+				       bool is_ipv6)
+{
+	__be16 protocol = skb->protocol;
+	const struct net_offload **offloads;
+	const struct net_offload *ops;
+	struct sk_buff *segs = ERR_PTR(-EINVAL);
+	struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
+					     netdev_features_t features);
+
+	rcu_read_lock();
+
+	switch (skb->inner_protocol_type) {
+	case ENCAP_TYPE_ETHER:
+		protocol = skb->inner_protocol;
+		gso_inner_segment = skb_mac_gso_segment;
+		break;
+	case ENCAP_TYPE_IPPROTO:
+		offloads = is_ipv6 ? inet6_offloads : inet_offloads;
+		ops = rcu_dereference(offloads[skb->inner_ipproto]);
+		if (!ops || !ops->callbacks.gso_segment)
+			goto out_unlock;
+		gso_inner_segment = ops->callbacks.gso_segment;
+		break;
+	default:
+		goto out_unlock;
+	}
+
+	segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment,
+					protocol);
+
+out_unlock:
+	rcu_read_unlock();
+
+	return segs;
+}
+
 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
 					 netdev_features_t features)
 {
@@ -113,7 +154,7 @@ static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
 	if (skb->encapsulation &&
 	    (skb_shinfo(skb)->gso_type &
 	     (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
-		segs = skb_udp_tunnel_segment(skb, features);
+		segs = skb_udp_tunnel_segment(skb, features, false);
 		goto out;
 	}
 
diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c
index 212ebfc..8f96988 100644
--- a/net/ipv6/udp_offload.c
+++ b/net/ipv6/udp_offload.c
@@ -58,7 +58,7 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
 
 	if (skb->encapsulation && skb_shinfo(skb)->gso_type &
 	    (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))
-		segs = skb_udp_tunnel_segment(skb, features);
+		segs = skb_udp_tunnel_segment(skb, features, true);
 	else {
 		const struct ipv6hdr *ipv6h;
 		struct udphdr *uh;
-- 
2.1.0.rc2.206.gedb03e5

[PATCH v2 net-next 2/5] sit: Set inner IP protocol in sit

[Tom Herbert]

Call skb_set_inner_ipproto to set inner IP protocol to IPPROTO_IPV6
before tunnel_xmit. This is needed if UDP encapsulation (fou) is
being done.

Signed-off-by: Tom Herbert <therbert@google.com>
---
 net/ipv6/sit.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index db75809..0d4e274 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -982,6 +982,8 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 		goto tx_error;
 	}
 
+	skb_set_inner_ipproto(skb, IPPROTO_IPV6);
+
 	err = iptunnel_xmit(skb->sk, rt, skb, fl4.saddr, fl4.daddr,
 			    protocol, tos, ttl, df,
 			    !net_eq(tunnel->net, dev_net(dev)));
@@ -1006,6 +1008,8 @@ static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 	if (IS_ERR(skb))
 		goto out;
 
+	skb_set_inner_ipproto(skb, IPPROTO_IPIP);
+
 	ip_tunnel_xmit(skb, dev, tiph, IPPROTO_IPIP);
 	return NETDEV_TX_OK;
 out:
-- 
2.1.0.rc2.206.gedb03e5

[PATCH v2 net-next 3/5] ipip: Set inner IP protocol in ipip

[Tom Herbert]

Call skb_set_inner_ipproto to set inner IP protocol to IPPROTO_IPV4
before tunnel_xmit. This is needed if UDP encapsulation (fou) is
being done.

Signed-off-by: Tom Herbert <therbert@google.com>
---
 net/ipv4/ipip.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
index bfec31d..ea88ab3 100644
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -224,6 +224,8 @@ static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 	if (IS_ERR(skb))
 		goto out;
 
+	skb_set_inner_ipproto(skb, IPPROTO_IPIP);
+
 	ip_tunnel_xmit(skb, dev, tiph, tiph->protocol);
 	return NETDEV_TX_OK;
 
-- 
2.1.0.rc2.206.gedb03e5

[PATCH v2 net-next 4/5] gre: Set inner protocol in v4 and v6 GRE transmit

[Tom Herbert]

Call skb_set_inner_protocol to set inner Ethernet protocol to
protocol being encapsulation by GRE before tunnel_xmit. This is
needed for GSO if UDP encapsulation (fou) is being done.

Signed-off-by: Tom Herbert <therbert@google.com>
---
 net/ipv4/ip_gre.c  | 2 ++
 net/ipv6/ip6_gre.c | 8 ++++++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 829aff8b..0485ef1 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -241,6 +241,8 @@ static void __gre_xmit(struct sk_buff *skb, struct net_device *dev,
 	/* Push GRE header. */
 	gre_build_header(skb, &tpi, tunnel->tun_hlen);
 
+	skb_set_inner_protocol(skb, tpi.proto);
+
 	ip_tunnel_xmit(skb, dev, tnl_params, tnl_params->protocol);
 }
 
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 5f19dfb..9a0a1aa 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -616,6 +616,7 @@ static netdev_tx_t ip6gre_xmit2(struct sk_buff *skb,
 	int err = -1;
 	u8 proto;
 	struct sk_buff *new_skb;
+	__be16 protocol;
 
 	if (dev->type == ARPHRD_ETHER)
 		IPCB(skb)->flags = 0;
@@ -732,8 +733,9 @@ static netdev_tx_t ip6gre_xmit2(struct sk_buff *skb,
 	ipv6h->daddr = fl6->daddr;
 
 	((__be16 *)(ipv6h + 1))[0] = tunnel->parms.o_flags;
-	((__be16 *)(ipv6h + 1))[1] = (dev->type == ARPHRD_ETHER) ?
-				   htons(ETH_P_TEB) : skb->protocol;
+	protocol = (dev->type == ARPHRD_ETHER) ?
+		    htons(ETH_P_TEB) : skb->protocol;
+	((__be16 *)(ipv6h + 1))[1] = protocol;
 
 	if (tunnel->parms.o_flags&(GRE_KEY|GRE_CSUM|GRE_SEQ)) {
 		__be32 *ptr = (__be32 *)(((u8 *)ipv6h) + tunnel->hlen - 4);
@@ -754,6 +756,8 @@ static netdev_tx_t ip6gre_xmit2(struct sk_buff *skb,
 		}
 	}
 
+	skb_set_inner_protocol(skb, protocol);
+
 	ip6tunnel_xmit(skb, dev);
 	if (ndst)
 		ip6_tnl_dst_store(tunnel, ndst);
-- 
2.1.0.rc2.206.gedb03e5

[PATCH v2 net-next 5/5] vxlan: Set inner protocol before transmit

[Tom Herbert]

Call skb_set_inner_protocol to set inner Ethernet protocol to
ETH_P_TEB before transmit. This is needed for GSO with UDP tunnels.

Signed-off-by: Tom Herbert <therbert@google.com>
---
 drivers/net/vxlan.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 34e102e..2af795d 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -1610,6 +1610,8 @@ static int vxlan6_xmit_skb(struct vxlan_sock *vs,
 	vxh->vx_flags = htonl(VXLAN_FLAGS);
 	vxh->vx_vni = vni;
 
+	skb_set_inner_protocol(skb, htons(ETH_P_TEB));
+
 	udp_tunnel6_xmit_skb(vs->sock, dst, skb, dev, saddr, daddr, prio,
 			     ttl, src_port, dst_port);
 	return 0;
@@ -1652,6 +1654,8 @@ int vxlan_xmit_skb(struct vxlan_sock *vs,
 	vxh->vx_flags = htonl(VXLAN_FLAGS);
 	vxh->vx_vni = vni;
 
+	skb_set_inner_protocol(skb, htons(ETH_P_TEB));
+
 	return udp_tunnel_xmit_skb(vs->sock, rt, skb, src, dst, tos,
 				   ttl, df, src_port, dst_port, xnet);
 }
-- 
2.1.0.rc2.206.gedb03e5

Re: [PATCH v2 net-next 0/5] udp: Generalize GSO for UDP tunnels

[David Miller]

From: Tom Herbert <therbert@google.com>
Date: Mon, 29 Sep 2014 20:22:28 -0700

> This patch set generalizes the UDP tunnel segmentation functions so
> that they can work with various protocol encapsulations. The primary
> change is to set the inner_protocol field in the skbuff when creating
> the encapsulated packet, and then in skb_udp_tunnel_segment this data
> is used to determine the function for segmenting the encapsulated
> packet. The inner_protocol field is overloaded to take either an
> Ethertype or IP protocol.
> 
> The inner_protocol is set on transmit using skb_set_inner_ipproto or
> skb_set_inner_protocol functions. VXLAN and IP tunnels (for fou GSO)
> were modified to call these.

Series applied, thanks Tom.