--- /dev/null
+/* 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.
+ */
+
+#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 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->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 = 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 = 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("");
+}
Code Review / kvmfornfv.git / blobdiff