Commit b20dc3c6 authored by Wojciech Drewek's avatar Wojciech Drewek Committed by Tony Nguyen
Browse files

gtp: Allow to create GTP device without FDs 



Currently, when the user wants to create GTP device, he has to
provide file handles to the sockets created in userspace (IFLA_GTP_FD0,
IFLA_GTP_FD1). This behaviour is not ideal, considering the option of
adding support for GTP device creation through ip link. Ip link
application is not a good place to create such sockets.

This patch allows to create GTP device without providing
IFLA_GTP_FD0 and IFLA_GTP_FD1 arguments. If the user sets
IFLA_GTP_CREATE_SOCKETS attribute, then GTP module takes care
of creating UDP sockets by itself. Sockets are created with the
commonly known UDP ports used for GTP protocol (GTP0_PORT and
GTP1U_PORT). In this case we don't have to provide encap_destroy
because no extra deinitialization is needed, everything is covered
by udp_tunnel_sock_release.

Note: GTP instance created with only this change applied, does
not handle GTP Echo Requests. This is implemented in the following
patch.

Signed-off-by: default avatarWojciech Drewek <wojciech.drewek@intel.com>
Signed-off-by: default avatarTony Nguyen <anthony.l.nguyen@intel.com>
parent 59d59235

drivers/net/gtp.c

+84 −17
Original line number Diff line number Diff line
@@ -66,8 +66,10 @@ struct gtp_dev { 


	struct sock		*sk0;

	struct sock		*sk1u;

	u8			sk_created;



	struct net_device	*dev;

	struct net		*net;



	unsigned int		role;

	unsigned int		hash_size;
@@ -320,9 +322,17 @@ static void gtp_encap_disable_sock(struct sock *sk) 


static void gtp_encap_disable(struct gtp_dev *gtp)

{

	if (gtp->sk_created) {

		udp_tunnel_sock_release(gtp->sk0->sk_socket);

		udp_tunnel_sock_release(gtp->sk1u->sk_socket);

		gtp->sk_created = false;

		gtp->sk0 = NULL;

		gtp->sk1u = NULL;

	} else {

		gtp_encap_disable_sock(gtp->sk0);

		gtp_encap_disable_sock(gtp->sk1u);

	}

}



/* UDP encapsulation receive handler. See net/ipv4/udp.c.

 * Return codes: 0: success, <0: error, >0: pass up to userspace UDP socket.
@@ -656,17 +666,69 @@ static void gtp_destructor(struct net_device *dev) 
	kfree(gtp->tid_hash);

}



static struct sock *gtp_create_sock(int type, struct gtp_dev *gtp)

{

	struct udp_tunnel_sock_cfg tuncfg = {};

	struct udp_port_cfg udp_conf = {

		.local_ip.s_addr	= htonl(INADDR_ANY),

		.family			= AF_INET,

	};

	struct net *net = gtp->net;

	struct socket *sock;

	int err;



	if (type == UDP_ENCAP_GTP0)

		udp_conf.local_udp_port = htons(GTP0_PORT);

	else if (type == UDP_ENCAP_GTP1U)

		udp_conf.local_udp_port = htons(GTP1U_PORT);

	else

		return ERR_PTR(-EINVAL);



	err = udp_sock_create(net, &udp_conf, &sock);

	if (err)

		return ERR_PTR(err);



	tuncfg.sk_user_data = gtp;

	tuncfg.encap_type = type;

	tuncfg.encap_rcv = gtp_encap_recv;

	tuncfg.encap_destroy = NULL;



	setup_udp_tunnel_sock(net, sock, &tuncfg);



	return sock->sk;

}



static int gtp_create_sockets(struct gtp_dev *gtp, struct nlattr *data[])

{

	struct sock *sk1u = NULL;

	struct sock *sk0 = NULL;



	sk0 = gtp_create_sock(UDP_ENCAP_GTP0, gtp);

	if (IS_ERR(sk0))

		return PTR_ERR(sk0);



	sk1u = gtp_create_sock(UDP_ENCAP_GTP1U, gtp);

	if (IS_ERR(sk1u)) {

		udp_tunnel_sock_release(sk0->sk_socket);

		return PTR_ERR(sk1u);

	}



	gtp->sk_created = true;

	gtp->sk0 = sk0;

	gtp->sk1u = sk1u;



	return 0;

}



static int gtp_newlink(struct net *src_net, struct net_device *dev,

		       struct nlattr *tb[], struct nlattr *data[],

		       struct netlink_ext_ack *extack)

{

	unsigned int role = GTP_ROLE_GGSN;

	struct gtp_dev *gtp;

	struct gtp_net *gn;

	int hashsize, err;



	if (!data[IFLA_GTP_FD0] && !data[IFLA_GTP_FD1])

		return -EINVAL;



	gtp = netdev_priv(dev);



	if (!data[IFLA_GTP_PDP_HASHSIZE]) {
@@ -677,10 +739,22 @@ static int gtp_newlink(struct net *src_net, struct net_device *dev, 
			hashsize = 1024;

	}



	if (data[IFLA_GTP_ROLE]) {

		role = nla_get_u32(data[IFLA_GTP_ROLE]);

		if (role > GTP_ROLE_SGSN)

			return -EINVAL;

	}

	gtp->role = role;



	gtp->net = src_net;



	err = gtp_hashtable_new(gtp, hashsize);

	if (err < 0)

		return err;



	if (data[IFLA_GTP_CREATE_SOCKETS])

		err = gtp_create_sockets(gtp, data);

	else

		err = gtp_encap_enable(gtp, data);

	if (err < 0)

		goto out_hashtable;
@@ -726,6 +800,7 @@ static const struct nla_policy gtp_policy[IFLA_GTP_MAX + 1] = { 
	[IFLA_GTP_FD1]			= { .type = NLA_U32 },

	[IFLA_GTP_PDP_HASHSIZE]		= { .type = NLA_U32 },

	[IFLA_GTP_ROLE]			= { .type = NLA_U32 },

	[IFLA_GTP_CREATE_SOCKETS]	= { .type = NLA_U8 },

};



static int gtp_validate(struct nlattr *tb[], struct nlattr *data[],
@@ -848,7 +923,9 @@ static int gtp_encap_enable(struct gtp_dev *gtp, struct nlattr *data[]) 
{

	struct sock *sk1u = NULL;

	struct sock *sk0 = NULL;

	unsigned int role = GTP_ROLE_GGSN;



	if (!data[IFLA_GTP_FD0] && !data[IFLA_GTP_FD1])

		return -EINVAL;



	if (data[IFLA_GTP_FD0]) {

		u32 fd0 = nla_get_u32(data[IFLA_GTP_FD0]);
@@ -868,18 +945,8 @@ static int gtp_encap_enable(struct gtp_dev *gtp, struct nlattr *data[]) 
		}

	}



	if (data[IFLA_GTP_ROLE]) {

		role = nla_get_u32(data[IFLA_GTP_ROLE]);

		if (role > GTP_ROLE_SGSN) {

			gtp_encap_disable_sock(sk0);

			gtp_encap_disable_sock(sk1u);

			return -EINVAL;

		}

	}



	gtp->sk0 = sk0;

	gtp->sk1u = sk1u;

	gtp->role = role;



	return 0;

}

include/uapi/linux/if_link.h

+1 −0
Original line number Diff line number Diff line
@@ -887,6 +887,7 @@ enum { 
	IFLA_GTP_FD1,

	IFLA_GTP_PDP_HASHSIZE,

	IFLA_GTP_ROLE,

	IFLA_GTP_CREATE_SOCKETS,

	__IFLA_GTP_MAX,

};

#define IFLA_GTP_MAX (__IFLA_GTP_MAX - 1)