[PATCH net-next 0/4] net: Generic UDP Encapsulation

[PATCH net-next 0/4] net: Generic UDP Encapsulation

[Tom Herbert]

Generic UDP Encapsulation (GUE) is UDP encapsulation protocol that
encapsulates packets of various IP protocols. The GUE protocol is
described in http://tools.ietf.org/html/draft-herbert-gue-01.

The receive path of GUE is implemented in the FOU over UDP module (FOU).
This includes a UDP encap receive function for GUE as well as GUE
specific GRO functions. Management and configuration of GUE ports shares
most of the same code with FOU.

For the transmit path, the previous FOU support for IPIP, sit, and GRE
was simply extended for GUE (when GUE is enabled insert the GUE
header on transmit in addition to UDP header inserted for FOU).

Semantically GUE is the same as FOU in that the encapsulation (UDP
and GUE headers) that are inserted on transmission and removed on
reception so that IP packet is processed with the inner header.

This patch set includes:
 - Some fixes to FOU, removal of IPv4,v6 specific GRO functions
 - Support to configure a GUE receive port
 - Implementation of GUE receive path (normal and GRO)
 - Additions to ip_tunnel netlink to configure GUE
 - GUE header inserion in ip_tunnel transmit path

Follow on patches will include

Testng:

I ran performance numbers using netperf TCP_RR with 200 streams,
comparing encapsulation without GUE, encapsulation with GUE, and
encapsulation with FOU.

 GRE
    TCP_STREAM
      IPv4, FOU, UDP checksum enabled
        14.04% TX CPU utilization
        13.17% RX CPU utilization
        9211 Mbps
      IPv4, GUE, UDP checksum enabled
        14.99% TX CPU utilization
        13.79% RX CPU utilization
        9185 Mbps
      IPv4, FOU, UDP checksum disabled
        13.14% TX CPU utilization
        23.18% RX CPU utilization
        9277 Mbps
      IPv4, GUE, UDP checksum disabled
        13.66% TX CPU utilization
        23.57% RX CPU utilization
        9184 Mbps
    TCP_RR
      IPv4, FOU, UDP checksum enabled
        94.2% CPU utilization
        155/249/460 90/95/99% latencies
        1.17018e+06 tps
      IPv4, GUE, UDP checksum enabled
        93.9% CPU utilization
        158/253/472 90/95/99% latencies
        1.15045e+06 tps


  IPIP
    TCP_STREAM
      FOU, UDP checksum enabled
        15.28% TX CPU utilization
        13.92% RX CPU utilization
        9342 Mbps
      GUE, UDP checksum enabled
        13.99% TX CPU utilization
        13.34% RX CPU utilization
        9210 Mbps
      FOU, UDP checksum disabled
        15.08% TX CPU utilization
        24.64% RX CPU utilization
        9226 Mbps
      GUE, UDP checksum disabled
        15.90% TX CPU utilization
        24.77% RX CPU utilization
        9197 Mbps
    TCP_RR
      FOU, UDP checksum enabled
        94.23% CPU utilization
        149/237/429 90/95/99% latencies
        1.19553e+06 tps
      GUE, UDP checksum enabled
        93.75% CPU utilization
        152/243/442 90/95/99% latencies
        1.17027e+06 tps

  SIT
    TCP_STREAM
      FOU, UDP checksum enabled
        14.47% TX CPU utilization
        14.58% RX CPU utilization
        9106 Mbps
      GUE, UDP checksum enabled
        15.09% TX CPU utilization
        14.84% RX CPU utilization
        9080 Mbps
      FOU, UDP checksum disabled
        15.70% TX CPU utilization
        27.93% RX CPU utilization
        9097 Mbps
      GUE, UDP checksum disabled
        15.04% TX CPU utilization
        27.54% RX CPU utilization
        9073 Mbps
    TCP_RR
      FOU, UDP checksum enabled
        96.9% CPU utilization
        170/281/581 90/95/99% latencies
        1.03372e+06 tps
      GUE, UDP checksum enabled
        97.16% CPU utilization
        172/286/576 90/95/99% latencies
        1.00469e+06 tps

Tom Herbert (4):
  ip_tunnel: Account for secondary encapsulation header in max_headroom
  fou: eliminate IPv4,v6 specific GRO functions
  gue: Receive side for Generic UDP Encapsulation
  ip_tunnel: Add GUE support

 include/linux/netdevice.h      |   3 +
 include/uapi/linux/fou.h       |   7 ++
 include/uapi/linux/if_tunnel.h |   1 +
 net/ipv4/fou.c                 | 224 ++++++++++++++++++++++++++++++++++-------
 net/ipv4/ip_tunnel.c           |  15 ++-
 net/ipv4/udp_offload.c         |   1 +
 net/ipv6/udp_offload.c         |   1 +
 7 files changed, 212 insertions(+), 40 deletions(-)

-- 
2.1.0.rc2.206.gedb03e5

[PATCH net-next 1/4] ip_tunnel: Account for secondary encapsulation header in max_headroom

[Tom Herbert]

When adjusting max_header for the tunnel interface based on egress
device we need to account for any extra bytes in secondary encapsulation
(e.g. FOU).

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

diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index b75b47b..54ace25 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -759,7 +759,7 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
 		df |= (inner_iph->frag_off&htons(IP_DF));
 
 	max_headroom = LL_RESERVED_SPACE(rt->dst.dev) + sizeof(struct iphdr)
-			+ rt->dst.header_len;
+			+ rt->dst.header_len + ip_encap_hlen(&tunnel->encap);
 	if (max_headroom > dev->needed_headroom)
 		dev->needed_headroom = max_headroom;
 
-- 
2.1.0.rc2.206.gedb03e5

[PATCH net-next 2/4] fou: eliminate IPv4,v6 specific GRO functions

[Tom Herbert]

This patch removes fou[46]_gro_receive and fou[46]_gro_complete
functions. The v4 or v6 variants were chosen for the UDP offloads
based on the address family of the socket this is not necessary
or correct. Alternatively, this patch adds is_ipv6 to napi_gro_skb.
This is set in udp6_gro_receive and unset in udp4_gro_receive. In
fou_gro_receive the value is used to select the correct inet_offloads
for the protocol of the outer IP header.

Signed-off-by: Tom Herbert <therbert@google.com>
---
 include/linux/netdevice.h |  3 +++
 net/ipv4/fou.c            | 48 ++++++++---------------------------------------
 net/ipv4/udp_offload.c    |  1 +
 net/ipv6/udp_offload.c    |  1 +
 4 files changed, 13 insertions(+), 40 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 9b7fbac..640f8d8 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1886,6 +1886,9 @@ struct napi_gro_cb {
 	/* Number of checksums via CHECKSUM_UNNECESSARY */
 	u8	csum_cnt:3;
 
+	/* Used in foo-over-udp, set in udp[46]_gro_receive */
+	u8	is_ipv6:1;
+
 	/* used to support CHECKSUM_COMPLETE for tunneling protocols */
 	__wsum	csum;
 
diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c
index dced89f..7e2126a 100644
--- a/net/ipv4/fou.c
+++ b/net/ipv4/fou.c
@@ -65,14 +65,15 @@ static int fou_udp_recv(struct sock *sk, struct sk_buff *skb)
 }
 
 static struct sk_buff **fou_gro_receive(struct sk_buff **head,
-					struct sk_buff *skb,
-					const struct net_offload **offloads)
+					struct sk_buff *skb)
 {
 	const struct net_offload *ops;
 	struct sk_buff **pp = NULL;
 	u8 proto = NAPI_GRO_CB(skb)->proto;
+	const struct net_offload **offloads;
 
 	rcu_read_lock();
+	offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
 	ops = rcu_dereference(offloads[proto]);
 	if (!ops || !ops->callbacks.gro_receive)
 		goto out_unlock;
@@ -85,14 +86,15 @@ out_unlock:
 	return pp;
 }
 
-static int fou_gro_complete(struct sk_buff *skb, int nhoff,
-			    const struct net_offload **offloads)
+static int fou_gro_complete(struct sk_buff *skb, int nhoff)
 {
 	const struct net_offload *ops;
 	u8 proto = NAPI_GRO_CB(skb)->proto;
 	int err = -ENOSYS;
+	const struct net_offload **offloads;
 
 	rcu_read_lock();
+	offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
 	ops = rcu_dereference(offloads[proto]);
 	if (WARN_ON(!ops || !ops->callbacks.gro_complete))
 		goto out_unlock;
@@ -105,28 +107,6 @@ out_unlock:
 	return err;
 }
 
-static struct sk_buff **fou4_gro_receive(struct sk_buff **head,
-					 struct sk_buff *skb)
-{
-	return fou_gro_receive(head, skb, inet_offloads);
-}
-
-static int fou4_gro_complete(struct sk_buff *skb, int nhoff)
-{
-	return fou_gro_complete(skb, nhoff, inet_offloads);
-}
-
-static struct sk_buff **fou6_gro_receive(struct sk_buff **head,
-					 struct sk_buff *skb)
-{
-	return fou_gro_receive(head, skb, inet6_offloads);
-}
-
-static int fou6_gro_complete(struct sk_buff *skb, int nhoff)
-{
-	return fou_gro_complete(skb, nhoff, inet6_offloads);
-}
-
 static int fou_add_to_port_list(struct fou *fou)
 {
 	struct fou *fout;
@@ -199,20 +179,8 @@ static int fou_create(struct net *net, struct fou_cfg *cfg,
 
 	sk->sk_allocation = GFP_ATOMIC;
 
-	switch (cfg->udp_config.family) {
-	case AF_INET:
-		fou->udp_offloads.callbacks.gro_receive = fou4_gro_receive;
-		fou->udp_offloads.callbacks.gro_complete = fou4_gro_complete;
-		break;
-	case AF_INET6:
-		fou->udp_offloads.callbacks.gro_receive = fou6_gro_receive;
-		fou->udp_offloads.callbacks.gro_complete = fou6_gro_complete;
-		break;
-	default:
-		err = -EPFNOSUPPORT;
-		goto error;
-	}
-
+	fou->udp_offloads.callbacks.gro_receive = fou_gro_receive;
+	fou->udp_offloads.callbacks.gro_complete = fou_gro_complete;
 	fou->udp_offloads.port = cfg->udp_config.local_udp_port;
 	fou->udp_offloads.ipproto = cfg->protocol;
 
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index 8c35f2c..507310e 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -334,6 +334,7 @@ static struct sk_buff **udp4_gro_receive(struct sk_buff **head,
 		skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
 					     inet_gro_compute_pseudo);
 skip:
+	NAPI_GRO_CB(skb)->is_ipv6 = 0;
 	return udp_gro_receive(head, skb, uh);
 
 flush:
diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c
index 8f96988..6b8f543 100644
--- a/net/ipv6/udp_offload.c
+++ b/net/ipv6/udp_offload.c
@@ -140,6 +140,7 @@ static struct sk_buff **udp6_gro_receive(struct sk_buff **head,
 					     ip6_gro_compute_pseudo);
 
 skip:
+	NAPI_GRO_CB(skb)->is_ipv6 = 1;
 	return udp_gro_receive(head, skb, uh);
 
 flush:
-- 
2.1.0.rc2.206.gedb03e5

[PATCH net-next 3/4] gue: Receive side for Generic UDP Encapsulation

[Tom Herbert]

This patch adds support receiving for GUE packets in the fou module. The
fou module now supports direct foo-over-udp (no encapsulation header)
and GUE. To support this a type parameter is added to the fou netlink
parameters.

For a GUE socket we define gue_udp_recv, gue_gro_receive, and
gue_gro_complete to handle the specifics of the GUE protocol. Most
of the code to manage and configure sockets is common with the fou.

Signed-off-by: Tom Herbert <therbert@google.com>
---
 include/uapi/linux/fou.h |   7 ++
 net/ipv4/fou.c           | 196 ++++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 194 insertions(+), 9 deletions(-)

diff --git a/include/uapi/linux/fou.h b/include/uapi/linux/fou.h
index e03376d..8df0689 100644
--- a/include/uapi/linux/fou.h
+++ b/include/uapi/linux/fou.h
@@ -13,6 +13,7 @@ enum {
 	FOU_ATTR_PORT,				/* u16 */
 	FOU_ATTR_AF,				/* u8 */
 	FOU_ATTR_IPPROTO,			/* u8 */
+	FOU_ATTR_TYPE,				/* u8 */
 
 	__FOU_ATTR_MAX,
 };
@@ -27,6 +28,12 @@ enum {
 	__FOU_CMD_MAX,
 };
 
+enum {
+	FOU_ENCAP_UNSPEC,
+	FOU_ENCAP_DIRECT,
+	FOU_ENCAP_GUE,
+};
+
 #define FOU_CMD_MAX	(__FOU_CMD_MAX - 1)
 
 #endif /* _UAPI_LINUX_FOU_H */
diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c
index 7e2126a..efa70ad 100644
--- a/net/ipv4/fou.c
+++ b/net/ipv4/fou.c
@@ -7,6 +7,7 @@
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <net/genetlink.h>
+#include <net/gue.h>
 #include <net/ip.h>
 #include <net/protocol.h>
 #include <net/udp.h>
@@ -27,6 +28,7 @@ struct fou {
 };
 
 struct fou_cfg {
+	u16 type;
 	u8 protocol;
 	struct udp_port_cfg udp_config;
 };
@@ -64,6 +66,41 @@ static int fou_udp_recv(struct sock *sk, struct sk_buff *skb)
 					  sizeof(struct udphdr));
 }
 
+static int gue_udp_recv(struct sock *sk, struct sk_buff *skb)
+{
+	struct fou *fou = fou_from_sock(sk);
+	size_t len;
+	struct guehdr *guehdr;
+	struct udphdr *uh;
+
+	if (!fou)
+		return 1;
+
+	len = sizeof(struct udphdr) + sizeof(struct guehdr);
+	if (!pskb_may_pull(skb, len))
+		goto drop;
+
+	uh = udp_hdr(skb);
+	guehdr = (struct guehdr *)&uh[1];
+
+	len += guehdr->hlen << 2;
+	if (!pskb_may_pull(skb, len))
+		goto drop;
+
+	if (guehdr->version != 0)
+		goto drop;
+
+	if (guehdr->flags) {
+		/* No support yet */
+		goto drop;
+	}
+
+	return fou_udp_encap_recv_deliver(skb, guehdr->next_hdr, len);
+drop:
+	kfree_skb(skb);
+	return 0;
+}
+
 static struct sk_buff **fou_gro_receive(struct sk_buff **head,
 					struct sk_buff *skb)
 {
@@ -107,6 +144,112 @@ out_unlock:
 	return err;
 }
 
+static struct sk_buff **gue_gro_receive(struct sk_buff **head,
+					struct sk_buff *skb)
+{
+	const struct net_offload **offloads;
+	const struct net_offload *ops;
+	struct sk_buff **pp = NULL;
+	struct sk_buff *p;
+	u8 proto;
+	struct guehdr *guehdr;
+	unsigned int hlen, guehlen;
+	unsigned int off;
+	int flush = 1;
+
+	off = skb_gro_offset(skb);
+	hlen = off + sizeof(*guehdr);
+	guehdr = skb_gro_header_fast(skb, off);
+	if (skb_gro_header_hard(skb, hlen)) {
+		guehdr = skb_gro_header_slow(skb, hlen, off);
+		if (unlikely(!guehdr))
+			goto out;
+	}
+
+	proto = guehdr->next_hdr;
+
+	rcu_read_lock();
+	offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
+	ops = rcu_dereference(offloads[proto]);
+	if (WARN_ON(!ops || !ops->callbacks.gro_receive))
+		goto out_unlock;
+
+	guehlen = sizeof(*guehdr) + (guehdr->hlen << 2);
+
+	hlen = off + guehlen;
+	if (skb_gro_header_hard(skb, hlen)) {
+		guehdr = skb_gro_header_slow(skb, hlen, off);
+		if (unlikely(!guehdr))
+			goto out_unlock;
+	}
+
+	flush = 0;
+
+	for (p = *head; p; p = p->next) {
+		const struct guehdr *guehdr2;
+
+		if (!NAPI_GRO_CB(p)->same_flow)
+			continue;
+
+		guehdr2 = (struct guehdr *)(p->data + off);
+
+		/* Compare base GUE header to be equal (covers
+		 * hlen, version, next_hdr, and flags.
+		 */
+		if (guehdr->word != guehdr2->word) {
+			NAPI_GRO_CB(p)->same_flow = 0;
+			continue;
+		}
+
+		/* Compare optional fields are the same. */
+		if (guehdr->hlen && memcmp(&guehdr[1], &guehdr2[1],
+					   guehdr->hlen << 2)) {
+			NAPI_GRO_CB(p)->same_flow = 0;
+			continue;
+		}
+	}
+
+	skb_gro_pull(skb, guehlen);
+
+	/* Adjusted NAPI_GRO_CB(skb)->csum after skb_gro_pull()*/
+	skb_gro_postpull_rcsum(skb, guehdr, guehlen);
+
+	pp = ops->callbacks.gro_receive(head, skb);
+
+out_unlock:
+	rcu_read_unlock();
+out:
+	NAPI_GRO_CB(skb)->flush |= flush;
+
+	return pp;
+}
+
+static int gue_gro_complete(struct sk_buff *skb, int nhoff)
+{
+	const struct net_offload **offloads;
+	struct guehdr *guehdr = (struct guehdr *)(skb->data + nhoff);
+	const struct net_offload *ops;
+	unsigned int guehlen;
+	u8 proto;
+	int err = -ENOENT;
+
+	proto = guehdr->next_hdr;
+
+	guehlen = sizeof(*guehdr) + (guehdr->hlen << 2);
+
+	rcu_read_lock();
+	offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
+	ops = rcu_dereference(offloads[proto]);
+	if (WARN_ON(!ops || !ops->callbacks.gro_complete))
+		goto out_unlock;
+
+	err = ops->callbacks.gro_complete(skb, nhoff + guehlen);
+
+out_unlock:
+	rcu_read_unlock();
+	return err;
+}
+
 static int fou_add_to_port_list(struct fou *fou)
 {
 	struct fou *fout;
@@ -142,6 +285,28 @@ static void fou_release(struct fou *fou)
 	kfree(fou);
 }
 
+static int fou_encap_init(struct sock *sk, struct fou *fou, struct fou_cfg *cfg)
+{
+	udp_sk(sk)->encap_rcv = fou_udp_recv;
+	fou->protocol = cfg->protocol;
+	fou->udp_offloads.callbacks.gro_receive = fou_gro_receive;
+	fou->udp_offloads.callbacks.gro_complete = fou_gro_complete;
+	fou->udp_offloads.port = cfg->udp_config.local_udp_port;
+	fou->udp_offloads.ipproto = cfg->protocol;
+
+	return 0;
+}
+
+static int gue_encap_init(struct sock *sk, struct fou *fou, struct fou_cfg *cfg)
+{
+	udp_sk(sk)->encap_rcv = gue_udp_recv;
+	fou->udp_offloads.callbacks.gro_receive = gue_gro_receive;
+	fou->udp_offloads.callbacks.gro_complete = gue_gro_complete;
+	fou->udp_offloads.port = cfg->udp_config.local_udp_port;
+
+	return 0;
+}
+
 static int fou_create(struct net *net, struct fou_cfg *cfg,
 		      struct socket **sockp)
 {
@@ -164,10 +329,24 @@ static int fou_create(struct net *net, struct fou_cfg *cfg,
 
 	sk = sock->sk;
 
-	/* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
-	fou->protocol = cfg->protocol;
-	fou->port =  cfg->udp_config.local_udp_port;
-	udp_sk(sk)->encap_rcv = fou_udp_recv;
+	fou->port = cfg->udp_config.local_udp_port;
+
+	/* Initial for fou type */
+	switch (cfg->type) {
+	case FOU_ENCAP_DIRECT:
+		err = fou_encap_init(sk, fou, cfg);
+		if (err)
+			goto error;
+		break;
+	case FOU_ENCAP_GUE:
+		err = gue_encap_init(sk, fou, cfg);
+		if (err)
+			goto error;
+		break;
+	default:
+		err = -EINVAL;
+		goto error;
+	}
 
 	udp_sk(sk)->encap_type = 1;
 	udp_encap_enable();
@@ -179,11 +358,6 @@ static int fou_create(struct net *net, struct fou_cfg *cfg,
 
 	sk->sk_allocation = GFP_ATOMIC;
 
-	fou->udp_offloads.callbacks.gro_receive = fou_gro_receive;
-	fou->udp_offloads.callbacks.gro_complete = fou_gro_complete;
-	fou->udp_offloads.port = cfg->udp_config.local_udp_port;
-	fou->udp_offloads.ipproto = cfg->protocol;
-
 	if (cfg->udp_config.family == AF_INET) {
 		err = udp_add_offload(&fou->udp_offloads);
 		if (err)
@@ -240,6 +414,7 @@ static struct nla_policy fou_nl_policy[FOU_ATTR_MAX + 1] = {
 	[FOU_ATTR_PORT] = { .type = NLA_U16, },
 	[FOU_ATTR_AF] = { .type = NLA_U8, },
 	[FOU_ATTR_IPPROTO] = { .type = NLA_U8, },
+	[FOU_ATTR_TYPE] = { .type = NLA_U8, },
 };
 
 static int parse_nl_config(struct genl_info *info,
@@ -267,6 +442,9 @@ static int parse_nl_config(struct genl_info *info,
 	if (info->attrs[FOU_ATTR_IPPROTO])
 		cfg->protocol = nla_get_u8(info->attrs[FOU_ATTR_IPPROTO]);
 
+	if (info->attrs[FOU_ATTR_TYPE])
+		cfg->type = nla_get_u8(info->attrs[FOU_ATTR_TYPE]);
+
 	return 0;
 }
 
-- 
2.1.0.rc2.206.gedb03e5

[PATCH net-next 4/4] ip_tunnel: Add GUE support

[Tom Herbert]

This patch allows configuring IPIP, sit, and GRE tunnels to use GUE.
This is very similar to fou excpet that we need to insert the GUE header
in addition to the UDP header on transmit.

Signed-off-by: Tom Herbert <therbert@google.com>
---
 include/uapi/linux/if_tunnel.h |  1 +
 net/ipv4/ip_tunnel.c           | 13 +++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/include/uapi/linux/if_tunnel.h b/include/uapi/linux/if_tunnel.h
index 7c832af..280d9e0 100644
--- a/include/uapi/linux/if_tunnel.h
+++ b/include/uapi/linux/if_tunnel.h
@@ -64,6 +64,7 @@ enum {
 enum tunnel_encap_types {
 	TUNNEL_ENCAP_NONE,
 	TUNNEL_ENCAP_FOU,
+	TUNNEL_ENCAP_GUE,
 };
 
 #define TUNNEL_ENCAP_FLAG_CSUM		(1<<0)
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index 54ace25..79f2ac0 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -56,6 +56,7 @@
 #include <net/netns/generic.h>
 #include <net/rtnetlink.h>
 #include <net/udp.h>
+#include <net/gue.h>
 
 #if IS_ENABLED(CONFIG_IPV6)
 #include <net/ipv6.h>
@@ -495,6 +496,8 @@ static int ip_encap_hlen(struct ip_tunnel_encap *e)
 		return 0;
 	case TUNNEL_ENCAP_FOU:
 		return sizeof(struct udphdr);
+	case TUNNEL_ENCAP_GUE:
+		return sizeof(struct udphdr) + sizeof(struct guehdr);
 	default:
 		return -EINVAL;
 	}
@@ -546,6 +549,15 @@ static int fou_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
 	skb_reset_transport_header(skb);
 	uh = udp_hdr(skb);
 
+	if (e->type == TUNNEL_ENCAP_GUE) {
+		struct guehdr *guehdr = (struct guehdr *)&uh[1];
+
+		guehdr->version = 0;
+		guehdr->hlen = 0;
+		guehdr->flags = 0;
+		guehdr->next_hdr = *protocol;
+	}
+
 	uh->dest = e->dport;
 	uh->source = sport;
 	uh->len = htons(skb->len);
@@ -565,6 +577,7 @@ int ip_tunnel_encap(struct sk_buff *skb, struct ip_tunnel *t,
 	case TUNNEL_ENCAP_NONE:
 		return 0;
 	case TUNNEL_ENCAP_FOU:
+	case TUNNEL_ENCAP_GUE:
 		return fou_build_header(skb, &t->encap, t->encap_hlen,
 					protocol, fl4);
 	default:
-- 
2.1.0.rc2.206.gedb03e5

Re: [PATCH net-next 0/4] net: Generic UDP Encapsulation

[David Miller]

From: Tom Herbert <therbert@google.com>
Date: Wed,  1 Oct 2014 21:46:35 -0700

> Generic UDP Encapsulation (GUE) is UDP encapsulation protocol that
> encapsulates packets of various IP protocols. The GUE protocol is
> described in http://tools.ietf.org/html/draft-herbert-gue-01.

Series applied, thanks Tom.

Re: [PATCH net-next 0/4] net: Generic UDP Encapsulation

[David Miller]

From: David Miller <davem@davemloft.net>
Date: Fri, 03 Oct 2014 13:10:29 -0700 (PDT)

> From: Tom Herbert <therbert@google.com>
> Date: Wed,  1 Oct 2014 21:46:35 -0700
> 
>> Generic UDP Encapsulation (GUE) is UDP encapsulation protocol that
>> encapsulates packets of various IP protocols. The GUE protocol is
>> described in http://tools.ietf.org/html/draft-herbert-gue-01.
> 
> Series applied, thanks Tom.

I had to revert, forgot to 'git add' this file?

net/ipv4/ip_tunnel.c:59:21: fatal error: net/gue.h: No such file or directory