Commit 56328486 authored by Tom Herbert's avatar Tom Herbert Committed by David S. Miller
Browse files

net: Changes to ip_tunnel to support foo-over-udp encapsulation 



This patch changes IP tunnel to support (secondary) encapsulation,
Foo-over-UDP. Changes include:

1) Adding tun_hlen as the tunnel header length, encap_hlen as the
   encapsulation header length, and hlen becomes the grand total
   of these.
2) Added common netlink define to support FOU encapsulation.
3) Routines to perform FOU encapsulation.

Signed-off-by: default avatarTom Herbert <therbert@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent afe93325

include/net/ip_tunnels.h

+18 −1
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include <net/gro_cells.h>

#include <net/inet_ecn.h>

#include <net/ip.h>

#include <net/netns/generic.h>

#include <net/rtnetlink.h>



#if IS_ENABLED(CONFIG_IPV6)
@@ -31,6 +32,13 @@ struct ip_tunnel_6rd_parm { 
};

#endif



struct ip_tunnel_encap {

	__u16			type;

	__u16			flags;

	__be16			sport;

	__be16			dport;

};



struct ip_tunnel_prl_entry {

	struct ip_tunnel_prl_entry __rcu *next;

	__be32				addr;
@@ -56,13 +64,18 @@ struct ip_tunnel { 
	/* These four fields used only by GRE */

	__u32		i_seqno;	/* The last seen seqno	*/

	__u32		o_seqno;	/* The last output seqno */

	int		hlen;		/* Precalculated header length */

	int		tun_hlen;	/* Precalculated header length */

	int		mlink;



	struct ip_tunnel_dst __percpu *dst_cache;



	struct ip_tunnel_parm parms;



	int		encap_hlen;	/* Encap header length (FOU,GUE) */

	struct ip_tunnel_encap encap;



	int		hlen;		/* tun_hlen + encap_hlen */



	/* for SIT */

#ifdef CONFIG_IPV6_SIT_6RD

	struct ip_tunnel_6rd_parm ip6rd;
@@ -114,6 +127,8 @@ void ip_tunnel_delete_net(struct ip_tunnel_net *itn, struct rtnl_link_ops *ops); 
void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,

		    const struct iphdr *tnl_params, const u8 protocol);

int ip_tunnel_ioctl(struct net_device *dev, struct ip_tunnel_parm *p, int cmd);

int ip_tunnel_encap(struct sk_buff *skb, struct ip_tunnel *t,

		    u8 *protocol, struct flowi4 *fl4);

int ip_tunnel_change_mtu(struct net_device *dev, int new_mtu);



struct rtnl_link_stats64 *ip_tunnel_get_stats64(struct net_device *dev,
@@ -131,6 +146,8 @@ int ip_tunnel_newlink(struct net_device *dev, struct nlattr *tb[], 
		      struct ip_tunnel_parm *p);

void ip_tunnel_setup(struct net_device *dev, int net_id);

void ip_tunnel_dst_reset_all(struct ip_tunnel *t);

int ip_tunnel_encap_setup(struct ip_tunnel *t,

			  struct ip_tunnel_encap *ipencap);



/* Extract dsfield from inner protocol */

static inline u8 ip_tunnel_get_dsfield(const struct iphdr *iph,

include/uapi/linux/if_tunnel.h

+12 −0
Original line number Diff line number Diff line
@@ -53,10 +53,22 @@ enum { 
	IFLA_IPTUN_6RD_RELAY_PREFIX,

	IFLA_IPTUN_6RD_PREFIXLEN,

	IFLA_IPTUN_6RD_RELAY_PREFIXLEN,

	IFLA_IPTUN_ENCAP_TYPE,

	IFLA_IPTUN_ENCAP_FLAGS,

	IFLA_IPTUN_ENCAP_SPORT,

	IFLA_IPTUN_ENCAP_DPORT,

	__IFLA_IPTUN_MAX,

};

#define IFLA_IPTUN_MAX	(__IFLA_IPTUN_MAX - 1)



enum tunnel_encap_types {

	TUNNEL_ENCAP_NONE,

	TUNNEL_ENCAP_FOU,

};



#define TUNNEL_ENCAP_FLAG_CSUM		(1<<0)

#define TUNNEL_ENCAP_FLAG_CSUM6		(1<<1)



/* SIT-mode i_flags */

#define	SIT_ISATAP	0x0001

net/ipv4/ip_tunnel.c

+90 −1
Original line number Diff line number Diff line
@@ -55,6 +55,7 @@ 
#include <net/net_namespace.h>

#include <net/netns/generic.h>

#include <net/rtnetlink.h>

#include <net/udp.h>



#if IS_ENABLED(CONFIG_IPV6)

#include <net/ipv6.h>
@@ -487,6 +488,91 @@ drop: 
}

EXPORT_SYMBOL_GPL(ip_tunnel_rcv);



static int ip_encap_hlen(struct ip_tunnel_encap *e)

{

	switch (e->type) {

	case TUNNEL_ENCAP_NONE:

		return 0;

	case TUNNEL_ENCAP_FOU:

		return sizeof(struct udphdr);

	default:

		return -EINVAL;

	}

}



int ip_tunnel_encap_setup(struct ip_tunnel *t,

			  struct ip_tunnel_encap *ipencap)

{

	int hlen;



	memset(&t->encap, 0, sizeof(t->encap));



	hlen = ip_encap_hlen(ipencap);

	if (hlen < 0)

		return hlen;



	t->encap.type = ipencap->type;

	t->encap.sport = ipencap->sport;

	t->encap.dport = ipencap->dport;

	t->encap.flags = ipencap->flags;



	t->encap_hlen = hlen;

	t->hlen = t->encap_hlen + t->tun_hlen;



	return 0;

}

EXPORT_SYMBOL_GPL(ip_tunnel_encap_setup);



static int fou_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,

			    size_t hdr_len, u8 *protocol, struct flowi4 *fl4)

{

	struct udphdr *uh;

	__be16 sport;

	bool csum = !!(e->flags & TUNNEL_ENCAP_FLAG_CSUM);

	int type = csum ? SKB_GSO_UDP_TUNNEL_CSUM : SKB_GSO_UDP_TUNNEL;



	skb = iptunnel_handle_offloads(skb, csum, type);



	if (IS_ERR(skb))

		return PTR_ERR(skb);



	/* Get length and hash before making space in skb */



	sport = e->sport ? : udp_flow_src_port(dev_net(skb->dev),

					       skb, 0, 0, false);



	skb_push(skb, hdr_len);



	skb_reset_transport_header(skb);

	uh = udp_hdr(skb);



	uh->dest = e->dport;

	uh->source = sport;

	uh->len = htons(skb->len);

	uh->check = 0;

	udp_set_csum(!(e->flags & TUNNEL_ENCAP_FLAG_CSUM), skb,

		     fl4->saddr, fl4->daddr, skb->len);



	*protocol = IPPROTO_UDP;



	return 0;

}



int ip_tunnel_encap(struct sk_buff *skb, struct ip_tunnel *t,

		    u8 *protocol, struct flowi4 *fl4)

{

	switch (t->encap.type) {

	case TUNNEL_ENCAP_NONE:

		return 0;

	case TUNNEL_ENCAP_FOU:

		return fou_build_header(skb, &t->encap, t->encap_hlen,

					protocol, fl4);

	default:

		return -EINVAL;

	}

}

EXPORT_SYMBOL(ip_tunnel_encap);



static int tnl_update_pmtu(struct net_device *dev, struct sk_buff *skb,

			    struct rtable *rt, __be16 df)

{
@@ -536,7 +622,7 @@ static int tnl_update_pmtu(struct net_device *dev, struct sk_buff *skb, 
}



void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,

		    const struct iphdr *tnl_params, const u8 protocol)

		    const struct iphdr *tnl_params, u8 protocol)

{

	struct ip_tunnel *tunnel = netdev_priv(dev);

	const struct iphdr *inner_iph;
@@ -617,6 +703,9 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev, 
	init_tunnel_flow(&fl4, protocol, dst, tnl_params->saddr,

			 tunnel->parms.o_key, RT_TOS(tos), tunnel->parms.link);



	if (ip_tunnel_encap(skb, tunnel, &protocol, &fl4) < 0)

		goto tx_error;



	rt = connected ? tunnel_rtable_get(tunnel, 0, &fl4.saddr) : NULL;



	if (!rt) {

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