1 files changed, 399 insertions, 0 deletions
diff --git a/net/rxrpc/peer.c b/net/rxrpc/peer.c
new file mode 100644
index 00000000000..ed38f5b17c1
--- /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() */