Commit 7b14e15a authored by Jeremy Kerr's avatar Jeremy Kerr Committed by David S. Miller
Browse files

mctp: Implement a timeout for tags 



Currently, a MCTP (local-eid,remote-eid,tag) tuple is allocated to a
socket on send, and only expires when the socket is closed.

This change introduces a tag timeout, freeing the tuple after a fixed
expiry - currently six seconds. This is greater than (but close to) the
max response timeout in upper-layer bindings.

Signed-off-by: default avatarJeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 43f55f23

include/net/mctp.h

+10 −0
Original line number Diff line number Diff line
@@ -62,6 +62,11 @@ struct mctp_sock { 
	 * by sk->net->keys_lock

	 */

	struct hlist_head keys;



	/* mechanism for expiring allocated keys; will release an allocated

	 * tag, and any netdev state for a request/response pairing

	 */

	struct timer_list key_expiry;

};



/* Key for matching incoming packets to sockets or reassembly contexts.
@@ -107,6 +112,8 @@ struct mctp_sock { 
 *      the (complete) reply, or during reassembly errors. Here, we clean up

 *      the reassembly context (marking reasm_dead, to prevent another from

 *      starting), and remove the socket from the netns & socket lists.

 *

 *    - through an expiry timeout, on a per-socket timer

 */

struct mctp_sk_key {

	mctp_eid_t	peer_addr;
@@ -138,6 +145,9 @@ struct mctp_sk_key { 


	/* key validity */

	bool		valid;



	/* expiry timeout; valid (above) cleared on expiry */

	unsigned long	expiry;

};



struct mctp_skb_cb {

net/mctp/af_mctp.c

+44 −0
Original line number Diff line number Diff line
@@ -223,16 +223,60 @@ static const struct proto_ops mctp_dgram_ops = { 
	.sendpage	= sock_no_sendpage,

};



static void mctp_sk_expire_keys(struct timer_list *timer)

{

	struct mctp_sock *msk = container_of(timer, struct mctp_sock,

					     key_expiry);

	struct net *net = sock_net(&msk->sk);

	unsigned long next_expiry, flags;

	struct mctp_sk_key *key;

	struct hlist_node *tmp;

	bool next_expiry_valid = false;



	spin_lock_irqsave(&net->mctp.keys_lock, flags);



	hlist_for_each_entry_safe(key, tmp, &msk->keys, sklist) {

		spin_lock(&key->lock);



		if (!time_after_eq(key->expiry, jiffies)) {

			key->valid = false;

			hlist_del_rcu(&key->hlist);

			hlist_del_rcu(&key->sklist);

			spin_unlock(&key->lock);

			mctp_key_unref(key);

			continue;

		}



		if (next_expiry_valid) {

			if (time_before(key->expiry, next_expiry))

				next_expiry = key->expiry;

		} else {

			next_expiry = key->expiry;

			next_expiry_valid = true;

		}

		spin_unlock(&key->lock);

	}



	spin_unlock_irqrestore(&net->mctp.keys_lock, flags);



	if (next_expiry_valid)

		mod_timer(timer, next_expiry);

}



static int mctp_sk_init(struct sock *sk)

{

	struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);



	INIT_HLIST_HEAD(&msk->keys);

	timer_setup(&msk->key_expiry, mctp_sk_expire_keys, 0);

	return 0;

}



static void mctp_sk_close(struct sock *sk, long timeout)

{

	struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);



	del_timer_sync(&msk->key_expiry);

	sk_common_release(sk);

}

net/mctp/route.c

+8 −0
Original line number Diff line number Diff line
@@ -24,6 +24,8 @@ 
#include <net/sock.h>



static const unsigned int mctp_message_maxlen = 64 * 1024;

static const unsigned long mctp_key_lifetime = 6 * CONFIG_HZ;





/* route output callbacks */

static int mctp_route_discard(struct mctp_route *route, struct sk_buff *skb)
@@ -175,6 +177,9 @@ static int mctp_key_add(struct mctp_sk_key *key, struct mctp_sock *msk) 


	if (!rc) {

		refcount_inc(&key->refs);

		key->expiry = jiffies + mctp_key_lifetime;

		timer_reduce(&msk->key_expiry, key->expiry);



		hlist_add_head(&key->hlist, &net->mctp.keys);

		hlist_add_head(&key->sklist, &msk->keys);

	}
@@ -497,6 +502,9 @@ static void mctp_reserve_tag(struct net *net, struct mctp_sk_key *key, 


	lockdep_assert_held(&mns->keys_lock);



	key->expiry = jiffies + mctp_key_lifetime;

	timer_reduce(&msk->key_expiry, key->expiry);



	/* we hold the net->key_lock here, allowing updates to both

	 * then net and sk

	 */