/* peer.c: Rx RPC peer management
*
* Copyright (C) 2002 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/sched.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <rxrpc/rxrpc.h>
#include <rxrpc/transport.h>
#include <rxrpc/peer.h>
#include <rxrpc/connection.h>
#include <rxrpc/call.h>
#include <rxrpc/message.h>
#include <linux/udp.h>
#include <linux/ip.h>
#include <net/sock.h>
#include <asm/uaccess.h>
#include <asm/div64.h>
#include "internal.h"
__RXACCT_DECL(atomic_t rxrpc_peer_count);
LIST_HEAD(rxrpc_peers);
DECLARE_RWSEM(rxrpc_peers_sem);
unsigned long rxrpc_peer_timeout = 12 * 60 * 60;
static void rxrpc_peer_do_timeout(struct rxrpc_peer *peer);
static void __rxrpc_peer_timeout(rxrpc_timer_t *timer)
{
struct rxrpc_peer *peer =
list_entry(timer, struct rxrpc_peer, timeout);
_debug("Rx PEER TIMEOUT [%p{u=%d}]", peer, atomic_read(&peer->usage));
rxrpc_peer_do_timeout(peer);
}
static const struct rxrpc_timer_ops rxrpc_peer_timer_ops = {
.timed_out = __rxrpc_peer_timeout,
};
/*****************************************************************************/
/*
* create a peer record
*/
static int __rxrpc_create_peer(struct rxrpc_transport *trans, __be32 addr,
struct rxrpc_peer **_peer)
{
struct rxrpc_peer *peer;
_enter("%p,%08x", trans, ntohl(addr));
/* allocate and initialise a peer record */
peer = kzalloc(sizeof(struct rxrpc_peer), GFP_KERNEL);
if (!peer) {
_leave(" = -ENOMEM");
return -ENOMEM;
}
atomic_set(&peer->usage, 1);
INIT_LIST_HEAD(&peer->link);
INIT_LIST_HEAD(&peer->proc_link);
INIT_LIST_HEAD(&peer->conn_idlist);
INIT_LIST_HEAD(&peer->conn_active);
INIT_LIST_HEAD(&peer->conn_graveyard);
spin_lock_init(&peer->conn_gylock);
init_waitqueue_head(&peer->conn_gy_waitq);
rwlock_init(&peer->conn_idlock);
rwlock_init(&peer->conn_lock);
atomic_set(&peer->conn_count, 0);
spin_lock_init(&peer->lock);
rxrpc_timer_init(&peer->timeout, &rxrpc_peer_timer_ops);
peer->addr.s_addr = addr;
peer->trans = trans;
peer->ops = trans->peer_ops;
__RXACCT(atomic_inc(&rxrpc_peer_count));
*_peer = peer;
_leave(" = 0 (%p)", peer);
return 0;
} /* end __rxrpc_create_peer() */
/*****************************************************************************/
/*
* find a peer record on the specified transport
* - returns (if successful) with peer record usage incremented
* - resurrects it from the graveyard if found there
*/
int rxrpc_peer_lookup(struct rxrpc_transport *trans, __be32 addr,
struct rxrpc_peer **_peer)
{
struct rxrpc_peer *peer, *candidate = NULL;
struct list_head *_p;
int ret;
_enter("%p{%hu},%08x", trans, trans->port, ntohl(addr));
/* [common case] search the transport's active list first */
read_lock(&trans->peer_lock);
list_for_each(_p, &trans->peer_active) {
peer = list_entry(_p, struct rxrpc_peer, link);
if (peer->addr.s_addr == addr)
goto found_active;
}
read_unlock(&trans->peer_lock);
/* [uncommon case] not active - create a candidate for a new record */
ret = __rxrpc_create_peer(trans, addr, &candidate);
if (ret < 0) {
_leave(" = %d", ret);
return ret;
}
/* search the active list again, just in case it appeared whilst we
* were busy */
write_lock(&trans->peer_lock);
list_for_each(_p, &trans->peer_active) {
peer = list_entry(_p, struct rxrpc_peer, link);
if (peer->addr.s_addr == addr)
goto found_active_second_chance;
}
/* search the transport's graveyard list */
spin_lock(&trans->peer_gylock);
list_for_each(_p, &trans->peer_graveyard) {
peer = list_entry(_p, struct rxrpc_peer, link);
if (peer->addr.s_addr == addr)
goto found_in_graveyard;
}
spin_unlock(&trans->peer_gylock);
/* we can now add the new candidate to the list
* - tell the application layer that this peer has been added
*/
rxrpc_get_transport(trans);
peer = candidate;
candidate = NULL;
if (peer->ops && peer->ops->adding) {
ret = peer->ops->adding(peer);
if (ret < 0) {
write_unlock(&trans->peer_lock);
__RXACCT(atomic_dec(&rxrpc_peer_count));
kfree(peer);
rxrpc_put_transport(trans);
_leave(" = %d", ret);
return ret;
}
}
atomic_inc(&trans->peer_count);
make_active:
list_add_tail(&peer->link, &trans->peer_active);
success_uwfree:
write_unlock(&trans->peer_lock);
if (candidate) {
__RXACCT(atomic_dec(&rxrpc_peer_count));
kfree(candidate);
}
if (list_empty(&peer->proc_link)) {
down_write(&rxrpc_peers_sem);
list_add_tail(&peer->proc_link, &rxrpc_peers);
up_write(&rxrpc_peers_sem);
}
success:
*_peer = peer;
_leave(" = 0 (%p{u=%d cc=%d})",
peer,
atomic_read(&peer->usage),
atomic_read(&peer->conn_count));
return 0;
/* handle the peer being found in the active list straight off */
found_active:
rxrpc_get_peer(peer);
read_unlock(&trans->peer_lock);
goto success;
/* handle resurrecting a peer from the graveyard */
found_in_graveyard:
rxrpc_get_peer(peer);
rxrpc_get_transport(peer->trans);
rxrpc_krxtimod_del_timer(&peer->timeout);
list_del_init(&peer->link);
spin_unlock(&trans->peer_gylock);
goto make_active;
/* handle finding the peer on the second time through the active
* list */
found_active_second_chance:
rxrpc_get_peer(peer);
goto success_uwfree;
} /* end rxrpc_peer_lookup() */
/*****************************************************************************/
/*
* finish with a peer record
* - it gets sent to the graveyard from where it can be resurrected or timed
* out
*/
void rxrpc_put_peer(struct rxrpc_peer *peer)
{
struct rxrpc_transport *trans = peer->trans;
_enter("%p{cc=%d a=%08x}",
peer,
atomic_read(&peer->conn_count),
ntohl(peer->addr.s_addr));
/* sanity check */
if (atomic_read(&peer->usage) <= 0)
BUG();
write_lock(&trans->peer_lock);
spin_lock(&trans->peer_gylock);
if (likely(!atomic_dec_and_test(&peer->usage))) {
spin_unlock(&trans->peer_gylock);
write_unlock(&trans->peer_lock);
_leave("");
return;
}
/* move to graveyard queue */
list_del(&peer->link);
write_unlock(&trans->peer_lock);
list_add_tail(&peer->link, &trans->peer_graveyard);
BUG_ON(!list_empty(&peer->conn_active));
rxrpc_krxtimod_add_timer(&peer->timeout, rxrpc_peer_timeout * HZ);
spin_unlock(&trans->peer_gylock);
rxrpc_put_transport(trans);
_leave(" [killed]");
} /* end rxrpc_put_peer() */
/*****************************************************************************/
/*
* handle a peer timing out in the graveyard
* - called from krxtimod
*/
static void rxrpc_peer_do_timeout(struct rxrpc_peer *peer)
{
struct rxrpc_transport *trans = peer->trans;
_enter("%p{u=%d cc=%d a=%08x}",
peer,
atomic_read(&peer->usage),
atomic_read(&peer->conn_count),
ntohl(peer->addr.s_addr));
BUG_ON(atomic_read(&peer->usage) < 0);
/* remove from graveyard if still dead */
spin_lock(&trans->peer_gylock);
if (atomic_read(&peer->usage) == 0)
list_del_init(&peer->link);
else
peer = NULL;
spin_unlock(&trans->peer_gylock);
if (!peer) {
_leave("");
return; /* resurrected */
}
/* clear all connections on this peer */
rxrpc_conn_clearall(peer);
BUG_ON(!list_empty(&peer->conn_active));
BUG_ON(!list_empty(&peer->conn_graveyard));
/* inform the application layer */
if (peer->ops && peer->ops->discarding)
peer->ops->discarding(peer);
if (!list_empty(&peer->proc_link)) {
down_write(&rxrpc_peers_sem);
list_del(&peer->proc_link);
up_write(&rxrpc_peers_sem);
}
__RXACCT(atomic_dec(&rxrpc_peer_count));
kfree(peer);
/* if the graveyard is now empty, wake up anyone waiting for that */
if (atomic_dec_and_test(&trans->peer_count))
wake_up(&trans->peer_gy_waitq);
_leave(" [destroyed]");
} /* end rxrpc_peer_do_timeout() */
/*****************************************************************************/
/*
* clear all peer records from a transport endpoint
*/
void rxrpc_peer_clearall(struct rxrpc_transport *trans)
{
DECLARE_WAITQUEUE(myself,current);
struct rxrpc_peer *peer;
int err;
_enter("%p",trans);
/* there shouldn't be any active peers remaining */
BUG_ON(!list_empty(&trans->peer_active));
/* manually timeout all peers in the graveyard */
spin_lock(&trans->peer_gylock);
while (!list_empty(&trans->peer_graveyard)) {
peer = list_entry(trans->peer_graveyard.next,
struct rxrpc_peer, link);
_debug("Clearing peer %p\n", peer);
err = rxrpc_krxtimod_del_timer(&peer->timeout);
spin_unlock(&trans->peer_gylock);
if (err == 0)
rxrpc_peer_do_timeout(peer);
spin_lock(&trans->peer_gylock);
}
spin_unlock(&trans->peer_gylock);
/* wait for the the peer graveyard to be completely cleared */
set_current_state(TASK_UNINTERRUPTIBLE);
add_wait_queue(&trans->peer_gy_waitq, &myself);
while (atomic_read(&trans->peer_count) != 0) {
schedule();
set_current_state(TASK_UNINTERRUPTIBLE);
}
remove_wait_queue(&trans->peer_gy_waitq, &myself);
set_current_state(TASK_RUNNING);
_leave("");
} /* end rxrpc_peer_clearall() */
/*****************************************************************************/
/*
* calculate and cache the Round-Trip-Time for a message and its response
*/
void rxrpc_peer_calculate_rtt(struct rxrpc_peer *peer,
struct rxrpc_message *msg,
struct rxrpc_message *resp)
{
unsigned long long rtt;
int loop;
_enter("%p,%p,%p", peer, msg, resp);
/* calculate the latest RTT */
rtt = resp->stamp.tv_sec - msg->stamp.tv_sec;
rtt *= 1000000UL;
rtt += resp->stamp.tv_usec - msg->stamp.tv_usec;
/* add to cache */
peer->rtt_cache[peer->rtt_point] = rtt;
peer->rtt_point++;
peer->rtt_point %= RXRPC_RTT_CACHE_SIZE;
if (peer->rtt_usage < RXRPC_RTT_CACHE_SIZE)
peer->rtt_usage++;
/* recalculate RTT */
rtt = 0;
for (loop = peer->rtt_usage - 1; loop >= 0; loop--)
rtt += peer->rtt_cache[loop];
do_div(rtt, peer->rtt_usage);
peer->rtt = rtt;
_leave(" RTT=%lu.%lums",
(long) (peer->rtt / 1000), (long) (peer->rtt % 1000));
} /* end rxrpc_peer_calculate_rtt() */
