1 files changed, 276 insertions, 0 deletions

diff --git a/net/rxrpc/ar-transport.c b/net/rxrpc/ar-transport.c
new file mode 100644
index 000000000000..9b4e5cb545d2
--- /dev/null
+++ b/net/rxrpc/ar-transport.c
@@ -0,0 +1,276 @@
+/* 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 <net/sock.h>
+#include <net/af_rxrpc.h>
+#include "ar-internal.h"
+
+static void rxrpc_transport_reaper(struct work_struct *work);
+
+static LIST_HEAD(rxrpc_transports);
+static DEFINE_RWLOCK(rxrpc_transport_lock);
+static unsigned long rxrpc_transport_timeout = 3600 * 24;
+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("{%u.%u.%u.%u+%hu},{%u.%u.%u.%u+%hu},",
+               NIPQUAD(local->srx.transport.sin.sin_addr),
+               ntohs(local->srx.transport.sin.sin_port),
+               NIPQUAD(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;
+
+        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, atomic_read(&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("{%u.%u.%u.%u+%hu},{%u.%u.%u.%u+%hu},",
+               NIPQUAD(local->srx.transport.sin.sin_addr),
+               ntohs(local->srx.transport.sin.sin_port),
+               NIPQUAD(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 = xtime.tv_sec;
+        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 */
+                schedule_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 = xtime.tv_sec;
+        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_timeout;
+                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);
+                schedule_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_timeout = 0;
+        cancel_delayed_work(&rxrpc_transport_reap);
+        schedule_delayed_work(&rxrpc_transport_reap, 0);
+
+        _leave("");
+}