net/rxrpc/ar-transport.c - linux - Git at Google

 /* RxRPC point-to-point transport session management
  *
  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * as published by the Free Software Foundation; either version
  * 2 of the License, or (at your option) any later version.
  */

 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

 #include <linux/module.h>
 #include <linux/net.h>
 #include <linux/skbuff.h>
 #include <linux/slab.h>
 #include <net/sock.h>
 #include <net/af_rxrpc.h>
 #include "ar-internal.h"

 /*
  * Time after last use at which transport record is cleaned up.
  */
 unsigned int rxrpc_transport_expiry = 3600 * 24;

 static void rxrpc_transport_reaper(struct work_struct *work);

 static LIST_HEAD(rxrpc_transports);
 static DEFINE_RWLOCK(rxrpc_transport_lock);
 static DECLARE_DELAYED_WORK(rxrpc_transport_reap, rxrpc_transport_reaper);

 /*
  * allocate a new transport session manager
  */
 static struct rxrpc_transport *rxrpc_alloc_transport(struct rxrpc_local *local,
 						     struct rxrpc_peer *peer,
 						     gfp_t gfp)
 {
 	struct rxrpc_transport *trans;

 	_enter("");

 	trans = kzalloc(sizeof(struct rxrpc_transport), gfp);
 	if (trans) {
 		trans->local = local;
 		trans->peer = peer;
 		INIT_LIST_HEAD(&trans->link);
 		trans->bundles = RB_ROOT;
 		trans->client_conns = RB_ROOT;
 		trans->server_conns = RB_ROOT;
 		skb_queue_head_init(&trans->error_queue);
 		spin_lock_init(&trans->client_lock);
 		rwlock_init(&trans->conn_lock);
 		atomic_set(&trans->usage, 1);
 		trans->conn_idcounter = peer->srx.srx_service << 16;
 		trans->debug_id = atomic_inc_return(&rxrpc_debug_id);

 		if (peer->srx.transport.family == AF_INET) {
 			switch (peer->srx.transport_type) {
 			case SOCK_DGRAM:
 				INIT_WORK(&trans->error_handler,
 					  rxrpc_UDP_error_handler);
 				break;
 			default:
 				BUG();
 				break;
 			}
 		} else {
 			BUG();
 		}
 	}

 	_leave(" = %p", trans);
 	return trans;
 }

 /*
  * obtain a transport session for the nominated endpoints
  */
 struct rxrpc_transport *rxrpc_get_transport(struct rxrpc_local *local,
 					    struct rxrpc_peer *peer,
 					    gfp_t gfp)
 {
 	struct rxrpc_transport *trans, *candidate;
 	const char *new = "old";
 	int usage;

 	_enter("{%pI4+%hu},{%pI4+%hu},",
 	       &local->srx.transport.sin.sin_addr,
 	       ntohs(local->srx.transport.sin.sin_port),
 	       &peer->srx.transport.sin.sin_addr,
 	       ntohs(peer->srx.transport.sin.sin_port));

 	/* search the transport list first */
 	read_lock_bh(&rxrpc_transport_lock);
 	list_for_each_entry(trans, &rxrpc_transports, link) {
 		if (trans->local == local && trans->peer == peer)
 			goto found_extant_transport;
 	}
 	read_unlock_bh(&rxrpc_transport_lock);

 	/* not yet present - create a candidate for a new record and then
 	 * redo the search */
 	candidate = rxrpc_alloc_transport(local, peer, gfp);
 	if (!candidate) {
 		_leave(" = -ENOMEM");
 		return ERR_PTR(-ENOMEM);
 	}

 	write_lock_bh(&rxrpc_transport_lock);

 	list_for_each_entry(trans, &rxrpc_transports, link) {
 		if (trans->local == local && trans->peer == peer)
 			goto found_extant_second;
 	}

 	/* we can now add the new candidate to the list */
 	trans = candidate;
 	candidate = NULL;
 	usage = atomic_read(&trans->usage);

 	rxrpc_get_local(trans->local);
 	atomic_inc(&trans->peer->usage);
 	list_add_tail(&trans->link, &rxrpc_transports);
 	write_unlock_bh(&rxrpc_transport_lock);
 	new = "new";

 success:
 	_net("TRANSPORT %s %d local %d -> peer %d",
 	     new,
 	     trans->debug_id,
 	     trans->local->debug_id,
 	     trans->peer->debug_id);

 	_leave(" = %p {u=%d}", trans, usage);
 	return trans;

 	/* we found the transport in the list immediately */
 found_extant_transport:
 	usage = atomic_inc_return(&trans->usage);
 	read_unlock_bh(&rxrpc_transport_lock);
 	goto success;

 	/* we found the transport on the second time through the list */
 found_extant_second:
 	usage = atomic_inc_return(&trans->usage);
 	write_unlock_bh(&rxrpc_transport_lock);
 	kfree(candidate);
 	goto success;
 }

 /*
  * find the transport connecting two endpoints
  */
 struct rxrpc_transport *rxrpc_find_transport(struct rxrpc_local *local,
 					     struct rxrpc_peer *peer)
 {
 	struct rxrpc_transport *trans;

 	_enter("{%pI4+%hu},{%pI4+%hu},",
 	       &local->srx.transport.sin.sin_addr,
 	       ntohs(local->srx.transport.sin.sin_port),
 	       &peer->srx.transport.sin.sin_addr,
 	       ntohs(peer->srx.transport.sin.sin_port));

 	/* search the transport list */
 	read_lock_bh(&rxrpc_transport_lock);

 	list_for_each_entry(trans, &rxrpc_transports, link) {
 		if (trans->local == local && trans->peer == peer)
 			goto found_extant_transport;
 	}

 	read_unlock_bh(&rxrpc_transport_lock);
 	_leave(" = NULL");
 	return NULL;

 found_extant_transport:
 	atomic_inc(&trans->usage);
 	read_unlock_bh(&rxrpc_transport_lock);
 	_leave(" = %p", trans);
 	return trans;
 }

 /*
  * release a transport session
  */
 void rxrpc_put_transport(struct rxrpc_transport *trans)
 {
 	_enter("%p{u=%d}", trans, atomic_read(&trans->usage));

 	ASSERTCMP(atomic_read(&trans->usage), >, 0);

 	trans->put_time = ktime_get_seconds();
 	if (unlikely(atomic_dec_and_test(&trans->usage))) {
 		_debug("zombie");
 		/* let the reaper determine the timeout to avoid a race with
 		 * overextending the timeout if the reaper is running at the
 		 * same time */
 		rxrpc_queue_delayed_work(&rxrpc_transport_reap, 0);
 	}
 	_leave("");
 }

 /*
  * clean up a transport session
  */
 static void rxrpc_cleanup_transport(struct rxrpc_transport *trans)
 {
 	_net("DESTROY TRANS %d", trans->debug_id);

 	rxrpc_purge_queue(&trans->error_queue);

 	rxrpc_put_local(trans->local);
 	rxrpc_put_peer(trans->peer);
 	kfree(trans);
 }

 /*
  * reap dead transports that have passed their expiry date
  */
 static void rxrpc_transport_reaper(struct work_struct *work)
 {
 	struct rxrpc_transport *trans, *_p;
 	unsigned long now, earliest, reap_time;

 	LIST_HEAD(graveyard);

 	_enter("");

 	now = ktime_get_seconds();
 	earliest = ULONG_MAX;

 	/* extract all the transports that have been dead too long */
 	write_lock_bh(&rxrpc_transport_lock);
 	list_for_each_entry_safe(trans, _p, &rxrpc_transports, link) {
 		_debug("reap TRANS %d { u=%d t=%ld }",
 		       trans->debug_id, atomic_read(&trans->usage),
 		       (long) now - (long) trans->put_time);

 		if (likely(atomic_read(&trans->usage) > 0))
 			continue;

 		reap_time = trans->put_time + rxrpc_transport_expiry;
 		if (reap_time <= now)
 			list_move_tail(&trans->link, &graveyard);
 		else if (reap_time < earliest)
 			earliest = reap_time;
 	}
 	write_unlock_bh(&rxrpc_transport_lock);

 	if (earliest != ULONG_MAX) {
 		_debug("reschedule reaper %ld", (long) earliest - now);
 		ASSERTCMP(earliest, >, now);
 		rxrpc_queue_delayed_work(&rxrpc_transport_reap,
 					 (earliest - now) * HZ);
 	}

 	/* then destroy all those pulled out */
 	while (!list_empty(&graveyard)) {
 		trans = list_entry(graveyard.next, struct rxrpc_transport,
 				   link);
 		list_del_init(&trans->link);

 		ASSERTCMP(atomic_read(&trans->usage), ==, 0);
 		rxrpc_cleanup_transport(trans);
 	}

 	_leave("");
 }

 /*
  * preemptively destroy all the transport session records rather than waiting
  * for them to time out
  */
 void __exit rxrpc_destroy_all_transports(void)
 {
 	_enter("");

 	rxrpc_transport_expiry = 0;
 	cancel_delayed_work(&rxrpc_transport_reap);
 	rxrpc_queue_delayed_work(&rxrpc_transport_reap, 0);

 	_leave("");
 }
	/* RxRPC point-to-point transport session management
	*
	* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
	* Written by David Howells (dhowells@redhat.com)
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version
	* 2 of the License, or (at your option) any later version.
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#include <linux/module.h>
	#include <linux/net.h>
	#include <linux/skbuff.h>
	#include <linux/slab.h>
	#include <net/sock.h>
	#include <net/af_rxrpc.h>
	#include "ar-internal.h"

	/*
	* Time after last use at which transport record is cleaned up.
	*/
	unsigned int rxrpc_transport_expiry = 3600 * 24;

	static void rxrpc_transport_reaper(struct work_struct *work);

	static LIST_HEAD(rxrpc_transports);
	static DEFINE_RWLOCK(rxrpc_transport_lock);
	static DECLARE_DELAYED_WORK(rxrpc_transport_reap, rxrpc_transport_reaper);

	/*
	* allocate a new transport session manager
	*/
	static struct rxrpc_transport rxrpc_alloc_transport(struct rxrpc_local local,
	struct rxrpc_peer *peer,
	gfp_t gfp)
	{
	struct rxrpc_transport *trans;

	_enter("");

	trans = kzalloc(sizeof(struct rxrpc_transport), gfp);
	if (trans) {
	trans->local = local;
	trans->peer = peer;
	INIT_LIST_HEAD(&trans->link);
	trans->bundles = RB_ROOT;
	trans->client_conns = RB_ROOT;
	trans->server_conns = RB_ROOT;
	skb_queue_head_init(&trans->error_queue);
	spin_lock_init(&trans->client_lock);
	rwlock_init(&trans->conn_lock);
	atomic_set(&trans->usage, 1);
	trans->conn_idcounter = peer->srx.srx_service << 16;
	trans->debug_id = atomic_inc_return(&rxrpc_debug_id);

	if (peer->srx.transport.family == AF_INET) {
	switch (peer->srx.transport_type) {
	case SOCK_DGRAM:
	INIT_WORK(&trans->error_handler,
	rxrpc_UDP_error_handler);
	break;
	default:
	BUG();
	break;
	}
	} else {
	BUG();
	}
	}

	_leave(" = %p", trans);
	return trans;
	}

	/*
	* obtain a transport session for the nominated endpoints
	*/
	struct rxrpc_transport rxrpc_get_transport(struct rxrpc_local local,
	struct rxrpc_peer *peer,
	gfp_t gfp)
	{
	struct rxrpc_transport trans, candidate;
	const char *new = "old";
	int usage;

	_enter("{%pI4+%hu},{%pI4+%hu},",
	&local->srx.transport.sin.sin_addr,
	ntohs(local->srx.transport.sin.sin_port),
	&peer->srx.transport.sin.sin_addr,
	ntohs(peer->srx.transport.sin.sin_port));

	/* search the transport list first */
	read_lock_bh(&rxrpc_transport_lock);
	list_for_each_entry(trans, &rxrpc_transports, link) {
	if (trans->local == local && trans->peer == peer)
	goto found_extant_transport;
	}
	read_unlock_bh(&rxrpc_transport_lock);

	/* not yet present - create a candidate for a new record and then
	* redo the search */
	candidate = rxrpc_alloc_transport(local, peer, gfp);
	if (!candidate) {
	_leave(" = -ENOMEM");
	return ERR_PTR(-ENOMEM);
	}

	write_lock_bh(&rxrpc_transport_lock);

	list_for_each_entry(trans, &rxrpc_transports, link) {
	if (trans->local == local && trans->peer == peer)
	goto found_extant_second;
	}

	/* we can now add the new candidate to the list */
	trans = candidate;
	candidate = NULL;
	usage = atomic_read(&trans->usage);

	rxrpc_get_local(trans->local);
	atomic_inc(&trans->peer->usage);
	list_add_tail(&trans->link, &rxrpc_transports);
	write_unlock_bh(&rxrpc_transport_lock);
	new = "new";

	success:
	_net("TRANSPORT %s %d local %d -> peer %d",
	new,
	trans->debug_id,
	trans->local->debug_id,
	trans->peer->debug_id);

	_leave(" = %p {u=%d}", trans, usage);
	return trans;

	/* we found the transport in the list immediately */
	found_extant_transport:
	usage = atomic_inc_return(&trans->usage);
	read_unlock_bh(&rxrpc_transport_lock);
	goto success;

	/* we found the transport on the second time through the list */
	found_extant_second:
	usage = atomic_inc_return(&trans->usage);
	write_unlock_bh(&rxrpc_transport_lock);
	kfree(candidate);
	goto success;
	}

	/*
	* find the transport connecting two endpoints
	*/
	struct rxrpc_transport rxrpc_find_transport(struct rxrpc_local local,
	struct rxrpc_peer *peer)
	{
	struct rxrpc_transport *trans;

	_enter("{%pI4+%hu},{%pI4+%hu},",
	&local->srx.transport.sin.sin_addr,
	ntohs(local->srx.transport.sin.sin_port),
	&peer->srx.transport.sin.sin_addr,
	ntohs(peer->srx.transport.sin.sin_port));

	/* search the transport list */
	read_lock_bh(&rxrpc_transport_lock);

	list_for_each_entry(trans, &rxrpc_transports, link) {
	if (trans->local == local && trans->peer == peer)
	goto found_extant_transport;
	}

	read_unlock_bh(&rxrpc_transport_lock);
	_leave(" = NULL");
	return NULL;

	found_extant_transport:
	atomic_inc(&trans->usage);
	read_unlock_bh(&rxrpc_transport_lock);
	_leave(" = %p", trans);
	return trans;
	}

	/*
	* release a transport session
	*/
	void rxrpc_put_transport(struct rxrpc_transport *trans)
	{
	_enter("%p{u=%d}", trans, atomic_read(&trans->usage));

	ASSERTCMP(atomic_read(&trans->usage), >, 0);

	trans->put_time = ktime_get_seconds();
	if (unlikely(atomic_dec_and_test(&trans->usage))) {
	_debug("zombie");
	/* let the reaper determine the timeout to avoid a race with
	* overextending the timeout if the reaper is running at the
	* same time */
	rxrpc_queue_delayed_work(&rxrpc_transport_reap, 0);
	}
	_leave("");
	}

	/*
	* clean up a transport session
	*/
	static void rxrpc_cleanup_transport(struct rxrpc_transport *trans)
	{
	_net("DESTROY TRANS %d", trans->debug_id);

	rxrpc_purge_queue(&trans->error_queue);

	rxrpc_put_local(trans->local);
	rxrpc_put_peer(trans->peer);
	kfree(trans);
	}

	/*
	* reap dead transports that have passed their expiry date
	*/
	static void rxrpc_transport_reaper(struct work_struct *work)
	{
	struct rxrpc_transport trans, _p;
	unsigned long now, earliest, reap_time;

	LIST_HEAD(graveyard);

	_enter("");

	now = ktime_get_seconds();
	earliest = ULONG_MAX;

	/* extract all the transports that have been dead too long */
	write_lock_bh(&rxrpc_transport_lock);
	list_for_each_entry_safe(trans, _p, &rxrpc_transports, link) {
	_debug("reap TRANS %d { u=%d t=%ld }",
	trans->debug_id, atomic_read(&trans->usage),
	(long) now - (long) trans->put_time);

	if (likely(atomic_read(&trans->usage) > 0))
	continue;

	reap_time = trans->put_time + rxrpc_transport_expiry;
	if (reap_time <= now)
	list_move_tail(&trans->link, &graveyard);
	else if (reap_time < earliest)
	earliest = reap_time;
	}
	write_unlock_bh(&rxrpc_transport_lock);

	if (earliest != ULONG_MAX) {
	_debug("reschedule reaper %ld", (long) earliest - now);
	ASSERTCMP(earliest, >, now);
	rxrpc_queue_delayed_work(&rxrpc_transport_reap,
	(earliest - now) * HZ);
	}

	/* then destroy all those pulled out */
	while (!list_empty(&graveyard)) {
	trans = list_entry(graveyard.next, struct rxrpc_transport,
	link);
	list_del_init(&trans->link);

	ASSERTCMP(atomic_read(&trans->usage), ==, 0);
	rxrpc_cleanup_transport(trans);
	}

	_leave("");
	}

	/*
	* preemptively destroy all the transport session records rather than waiting
	* for them to time out
	*/
	void __exit rxrpc_destroy_all_transports(void)
	{
	_enter("");

	rxrpc_transport_expiry = 0;
	cancel_delayed_work(&rxrpc_transport_reap);
	rxrpc_queue_delayed_work(&rxrpc_transport_reap, 0);

	_leave("");
	}