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gtp: Allow to create GTP device without FDs

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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: Wojciech Drewek <wojciech.drewek@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
This commit is contained in:
Wojciech Drewek 2022-03-04 17:40:42 +01:00 committed by Tony Nguyen
parent 59d5923536
commit b20dc3c684
2 changed files with 85 additions and 17 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

95
drivers/net/gtp.c
View file

@ -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;
}

1
include/uapi/linux/if_link.h
View file

@ -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)