diff options
Diffstat (limited to 'net/rxrpc/peer.c')
| -rw-r--r-- | net/rxrpc/peer.c | 399 |
1 files changed, 399 insertions, 0 deletions
diff --git a/net/rxrpc/peer.c b/net/rxrpc/peer.c new file mode 100644 index 000000000000..ed38f5b17c1b --- /dev/null +++ b/net/rxrpc/peer.c @@ -0,0 +1,399 @@ +/* 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 = kmalloc(sizeof(struct rxrpc_peer), GFP_KERNEL); + if (!peer) { + _leave(" = -ENOMEM"); + return -ENOMEM; + } + + memset(peer, 0, sizeof(struct rxrpc_peer)); + 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() */ |