Commit 2e7a2806 authored by James Chapman's avatar James Chapman Committed by David S. Miller
Browse files

l2tp: lookup tunnel from socket without using sk_user_data 



l2tp_sk_to_tunnel derives the tunnel from sk_user_data. Instead,
lookup the tunnel by walking the tunnel IDR for a tunnel using the
indicated sock. This is slow but l2tp_sk_to_tunnel is not used in
the datapath so performance isn't critical.

l2tp_tunnel_destruct needs a variant of l2tp_sk_to_tunnel which does
not bump the tunnel refcount since the tunnel refcount is already 0.

Change l2tp_sk_to_tunnel sk arg to const since it does not modify sk.

Signed-off-by: default avatarJames Chapman <jchapman@katalix.com>
Signed-off-by: default avatarTom Parkin <tparkin@katalix.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0a658d08

net/l2tp/l2tp_core.c

+43 −9
Original line number Diff line number Diff line
@@ -150,16 +150,44 @@ static void l2tp_session_free(struct l2tp_session *session) 
	kfree(session);

}



struct l2tp_tunnel *l2tp_sk_to_tunnel(struct sock *sk)

static struct l2tp_tunnel *__l2tp_sk_to_tunnel(const struct sock *sk)

{

	struct l2tp_tunnel *tunnel = sk->sk_user_data;

	const struct net *net = sock_net(sk);

	unsigned long tunnel_id, tmp;

	struct l2tp_tunnel *tunnel;

	struct l2tp_net *pn;



	WARN_ON_ONCE(!rcu_read_lock_bh_held());

	pn = l2tp_pernet(net);

	idr_for_each_entry_ul(&pn->l2tp_tunnel_idr, tunnel, tmp, tunnel_id) {

		if (tunnel && tunnel->sock == sk)

			return tunnel;

	}



	if (tunnel)

		if (WARN_ON(tunnel->magic != L2TP_TUNNEL_MAGIC))

	return NULL;

}



struct l2tp_tunnel *l2tp_sk_to_tunnel(const struct sock *sk)

{

	const struct net *net = sock_net(sk);

	unsigned long tunnel_id, tmp;

	struct l2tp_tunnel *tunnel;

	struct l2tp_net *pn;



	rcu_read_lock_bh();

	pn = l2tp_pernet(net);

	idr_for_each_entry_ul(&pn->l2tp_tunnel_idr, tunnel, tmp, tunnel_id) {

		if (tunnel &&

		    tunnel->sock == sk &&

		    refcount_inc_not_zero(&tunnel->ref_count)) {

			rcu_read_unlock_bh();

			return tunnel;

		}

	}

	rcu_read_unlock_bh();



	return NULL;

}

EXPORT_SYMBOL_GPL(l2tp_sk_to_tunnel);



void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel)
@@ -1213,8 +1241,10 @@ EXPORT_SYMBOL_GPL(l2tp_xmit_skb); 
 */

static void l2tp_tunnel_destruct(struct sock *sk)

{

	struct l2tp_tunnel *tunnel = l2tp_sk_to_tunnel(sk);

	struct l2tp_tunnel *tunnel;



	rcu_read_lock_bh();

	tunnel = __l2tp_sk_to_tunnel(sk);

	if (!tunnel)

		goto end;
@@ -1242,6 +1272,7 @@ static void l2tp_tunnel_destruct(struct sock *sk) 


	kfree_rcu(tunnel, rcu);

end:

	rcu_read_unlock_bh();

	return;

}
@@ -1308,10 +1339,13 @@ static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel) 
/* Tunnel socket destroy hook for UDP encapsulation */

static void l2tp_udp_encap_destroy(struct sock *sk)

{

	struct l2tp_tunnel *tunnel = l2tp_sk_to_tunnel(sk);

	struct l2tp_tunnel *tunnel;



	if (tunnel)

	tunnel = l2tp_sk_to_tunnel(sk);

	if (tunnel) {

		l2tp_tunnel_delete(tunnel);

		l2tp_tunnel_dec_refcount(tunnel);

	}

}



static void l2tp_tunnel_remove(struct net *net, struct l2tp_tunnel *tunnel)

net/l2tp/l2tp_core.h

+1 −4
Original line number Diff line number Diff line
@@ -273,10 +273,7 @@ void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type); 
/* IOCTL helper for IP encap modules. */

int l2tp_ioctl(struct sock *sk, int cmd, int *karg);



/* Extract the tunnel structure from a socket's sk_user_data pointer,

 * validating the tunnel magic feather.

 */

struct l2tp_tunnel *l2tp_sk_to_tunnel(struct sock *sk);

struct l2tp_tunnel *l2tp_sk_to_tunnel(const struct sock *sk);



static inline int l2tp_get_l2specific_len(struct l2tp_session *session)

{

net/l2tp/l2tp_ip.c

+5 −2
Original line number Diff line number Diff line
@@ -235,14 +235,17 @@ static void l2tp_ip_close(struct sock *sk, long timeout) 


static void l2tp_ip_destroy_sock(struct sock *sk)

{

	struct l2tp_tunnel *tunnel = l2tp_sk_to_tunnel(sk);

	struct l2tp_tunnel *tunnel;

	struct sk_buff *skb;



	while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)

		kfree_skb(skb);



	if (tunnel)

	tunnel = l2tp_sk_to_tunnel(sk);

	if (tunnel) {

		l2tp_tunnel_delete(tunnel);

		l2tp_tunnel_dec_refcount(tunnel);

	}

}



static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)

net/l2tp/l2tp_ip6.c

+5 −2
Original line number Diff line number Diff line
@@ -246,14 +246,17 @@ static void l2tp_ip6_close(struct sock *sk, long timeout) 


static void l2tp_ip6_destroy_sock(struct sock *sk)

{

	struct l2tp_tunnel *tunnel = l2tp_sk_to_tunnel(sk);

	struct l2tp_tunnel *tunnel;



	lock_sock(sk);

	ip6_flush_pending_frames(sk);

	release_sock(sk);



	if (tunnel)

	tunnel = l2tp_sk_to_tunnel(sk);

	if (tunnel) {

		l2tp_tunnel_delete(tunnel);

		l2tp_tunnel_dec_refcount(tunnel);

	}

}



static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)