path: root/net/rxrpc/ar-connection.c

/* RxRPC virtual connection handler
 *
 * 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.
 */

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

static void rxrpc_connection_reaper(struct work_struct *work);

LIST_HEAD(rxrpc_connections);
DEFINE_RWLOCK(rxrpc_connection_lock);
static unsigned long rxrpc_connection_timeout = 10 * 60;
static DECLARE_DELAYED_WORK(rxrpc_connection_reap, rxrpc_connection_reaper);

/*
 * allocate a new client connection bundle
 */
static struct rxrpc_conn_bundle *rxrpc_alloc_bundle(gfp_t gfp)
{
	struct rxrpc_conn_bundle *bundle;

	_enter("");

	bundle = kzalloc(sizeof(struct rxrpc_conn_bundle), gfp);
	if (bundle) {
		INIT_LIST_HEAD(&bundle->unused_conns);
		INIT_LIST_HEAD(&bundle->avail_conns);
		INIT_LIST_HEAD(&bundle->busy_conns);
		init_waitqueue_head(&bundle->chanwait);
		atomic_set(&bundle->usage, 1);
	}

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

/*
 * compare bundle parameters with what we're looking for
 * - return -ve, 0 or +ve
 */
static inline
int rxrpc_cmp_bundle(const struct rxrpc_conn_bundle *bundle,
		     struct key *key, __be16 service_id)
{
	return (bundle->service_id - service_id) ?:
		((unsigned long) bundle->key - (unsigned long) key);
}

/*
 * get bundle of client connections that a client socket can make use of
 */
struct rxrpc_conn_bundle *rxrpc_get_bundle(struct rxrpc_sock *rx,
					   struct rxrpc_transport *trans,
					   struct key *key,
					   __be16 service_id,
					   gfp_t gfp)
{
	struct rxrpc_conn_bundle *bundle, *candidate;
	struct rb_node *p, *parent, **pp;

	_enter("%p{%x},%x,%hx,",
	       rx, key_serial(key), trans->debug_id, ntohs(service_id));

	if (rx->trans == trans && rx->bundle) {
		atomic_inc(&rx->bundle->usage);
		return rx->bundle;
	}

	/* search the extant bundles first for one that matches the specified
	 * user ID */
	spin_lock(&trans->client_lock);

	p = trans->bundles.rb_node;
	while (p) {
		bundle = rb_entry(p, struct rxrpc_conn_bundle, node);

		if (rxrpc_cmp_bundle(bundle, key, service_id) < 0)
			p = p->rb_left;
		else if (rxrpc_cmp_bundle(bundle, key, service_id) > 0)
			p = p->rb_right;
		else
			goto found_extant_bundle;
	}

	spin_unlock(&trans->client_lock);

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

	candidate->key = key_get(key);
	candidate->service_id = service_id;

	spin_lock(&trans->client_lock);

	pp = &trans->bundles.rb_node;
	parent = NULL;
	while (*pp) {
		parent = *pp;
		bundle = rb_entry(parent, struct rxrpc_conn_bundle, node);

		if (rxrpc_cmp_bundle(bundle, key, service_id) < 0)
			pp = &(*pp)->rb_left;
		else if (rxrpc_cmp_bundle(bundle, key, service_id) > 0)
			pp = &(*pp)->rb_right;
		else
			goto found_extant_second;
	}

	/* second search also failed; add the new bundle */
	bundle = candidate;
	candidate = NULL;

	rb_link_node(&bundle->node, parent, pp);
	rb_insert_color(&bundle->node, &trans->bundles);
	spin_unlock(&trans->client_lock);
	_net("BUNDLE new on trans %d", trans->debug_id);
	if (!rx->bundle && rx->sk.sk_state == RXRPC_CLIENT_CONNECTED) {
		atomic_inc(&bundle->usage);
		rx->bundle = bundle;
	}
	_leave(" = %p [new]", bundle);
	return bundle;

	/* we found the bundle in the list immediately */
found_extant_bundle:
	atomic_inc(&bundle->usage);
	spin_unlock(&trans->client_lock);
	_net("BUNDLE old on trans %d", trans->debug_id);
	if (!rx->bundle && rx->sk.sk_state == RXRPC_CLIENT_CONNECTED) {
		atomic_inc(&bundle->usage);
		rx->bundle = bundle;
	}
	_leave(" = %p [extant %d]", bundle, atomic_read(&bundle->usage));
	return bundle;

	/* we found the bundle on the second