Initial import

1 files changed, 928 insertions, 0 deletions

diff --git a/net/rxrpc/ar-connection.c b/net/rxrpc/ar-connection.c
new file mode 100644
index 000000000..6631f4f1e
--- /dev/null
+++ b/net/rxrpc/ar-connection.c
@@ -0,0 +1,928 @@
+/* RxRPC virtual connection handler
+ *
+ * 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/slab.h>
+#include <linux/net.h>
+#include <linux/skbuff.h>
+#include <linux/crypto.h>
+#include <net/sock.h>
+#include <net/af_rxrpc.h>
+#include "ar-internal.h"
+
+/*
+ * Time till a connection expires after last use (in seconds).
+ */
+unsigned rxrpc_connection_expiry = 10 * 60;
+
+static void rxrpc_connection_reaper(struct work_struct *work);
+
+LIST_HEAD(rxrpc_connections);
+DEFINE_RWLOCK(rxrpc_connection_lock);
+static DECLARE_DELAYED_WORK(rxrpc_connection_reap, rxrpc_connection_reaper);
+
+/*
+ * allocate a new client connection bundle
+ */
+static struct rxrpc_conn_bundle *rxrpc_alloc_bundle(gfp_t gfp)
+{
+	struct rxrpc_conn_bundle *bundle;
+
+	_enter("");
+
+	bundle = kzalloc(sizeof(struct rxrpc_conn_bundle), gfp);
+	if (bundle) {
+		INIT_LIST_HEAD(&bundle->unused_conns);
+		INIT_LIST_HEAD(&bundle->avail_conns);
+		INIT_LIST_HEAD(&bundle->busy_conns);
+		init_waitqueue_head(&bundle->chanwait);
+		atomic_set(&bundle->usage, 1);
+	}
+
+	_leave(" = %p", bundle);
+	return bundle;
+}
+
+/*
+ * compare bundle parameters with what we're looking for
+ * - return -ve, 0 or +ve
+ */
+static inline
+int rxrpc_cmp_bundle(const struct rxrpc_conn_bundle *bundle,
+		     struct key *key, __be16 service_id)
+{
+	return (bundle->service_id - service_id) ?:
+		((unsigned long) bundle->key - (unsigned long) key);
+}
+
+/*
+ * get bundle of client connections that a client socket can make use of
+ */
+struct rxrpc_conn_bundle *rxrpc_get_bundle(struct rxrpc_sock *rx,
+					   struct rxrpc_transport *trans,
+					   struct key *key,
+					   __be16 service_id,
+					   gfp_t gfp)
+{
+	struct rxrpc_conn_bundle *bundle, *candidate;
+	struct rb_node *p, *parent, **pp;
+
+	_enter("%p{%x},%x,%hx,",
+	       rx, key_serial(key), trans->debug_id, ntohs(service_id));
+
+	if (rx->trans == trans && rx->bundle) {
+		atomic_inc(&rx->bundle->usage);
+		return rx->bundle;
+	}
+
+	/* search the extant bundles first for one that matches the specified
+	 * user ID */
+	spin_lock(&trans->client_lock);
+
+	p = trans->bundles.rb_node;
+	while (p) {
+		bundle = rb_entry(p, struct rxrpc_conn_bundle, node);
+
+		if (rxrpc_cmp_bundle(bundle, key, service_id) < 0)
+			p = p->rb_left;
+		else if (rxrpc_cmp_bundle(bundle, key, service_id) > 0)
+			p = p->rb_right;
+		else
+			goto found_extant_bundle;
+	}
+
+	spin_unlock(&trans->client_lock);
+
+	/* not yet present - create a candidate for a new record and then
+	 * redo the search */
+	candidate = rxrpc_alloc_bundle(gfp);
+	if (!candidate) {
+		_leave(" = -ENOMEM");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	candidate->key = key_get(key);
+	candidate->service_id = service_id;
+
+	spin_lock(&trans->client_lock);
+
+	pp = &trans->bundles.rb_node;
+	parent = NULL;
+	while (*pp) {
+		parent = *pp;
+		bundle = rb_entry(parent, struct rxrpc_conn_bundle, node);
+
+		if (rxrpc_cmp_bundle(bundle, key, service_id) < 0)
+			pp = &(*pp)->rb_left;
+		else if (rxrpc_cmp_bundle(bundle, key, service_id) > 0)
+			pp = &(*pp)->rb_right;
+		else
+			goto found_extant_second;
+	}
+
+	/* second search also failed; add the new bundle */
+	bundle = candidate;
+	candidate = NULL;
+
+	rb_link_node(&bundle->node, parent, pp);
+	rb_insert_color(&bundle->node, &trans->bundles);
+	spin_unlock(&trans->client_lock);
+	_net("BUNDLE new on trans %d", trans->debug_id);
+	if (!rx->bundle && rx->sk.sk_state == RXRPC_CLIENT_CONNECTED) {
+		atomic_inc(&bundle->usage);
+		rx->bundle = bundle;
+	}
+	_leave(" = %p [new]", bundle);
+	return bundle;
+
+	/* we found the bundle in the list immediately */
+found_extant_bundle:
+	atomic_inc(&bundle->usage);
+	spin_unlock(&trans->client_lock);
+	_net("BUNDLE old on trans %d", trans->debug_id);
+	if (!rx->bundle && rx->sk.sk_state == RXRPC_CLIENT_CONNECTED) {
+		atomic_inc(&bundle->usage);
+		rx->bundle = bundle;
+	}
+	_leave(" = %p [extant %d]", bundle, atomic_read(&bundle->usage));
+	return bundle;
+
+	/* we found the bundle on the second time through the list */
+found_extant_second:
+	atomic_inc(&bundle->usage);
+	spin_unlock(&trans->client_lock);
+	kfree(candidate);
+	_net("BUNDLE old2 on trans %d", trans->debug_id);
+	if (!rx->bundle && rx->sk.sk_state == RXRPC_CLIENT_CONNECTED) {
+		atomic_inc(&bundle->usage);
+		rx->bundle = bundle;
+	}
+	_leave(" = %p [second %d]", bundle, atomic_read(&bundle->usage));
+	return bundle;
+}
+
+/*
+ * release a bundle
+ */
+void rxrpc_put_bundle(struct rxrpc_transport *trans,
+		      struct rxrpc_conn_bundle *bundle)
+{
+	_enter("%p,%p{%d}",trans, bundle, atomic_read(&bundle->usage));
+
+	if (atomic_dec_and_lock(&bundle->usage, &trans->client_lock)) {
+		_debug("Destroy bundle");
+		rb_erase(&bundle->node, &trans->bundles);
+		spin_unlock(&trans->client_lock);
+		ASSERT(list_empty(&bundle->unused_conns));
+		ASSERT(list_empty(&bundle->avail_conns));
+		ASSERT(list_empty(&bundle->busy_conns));
+		ASSERTCMP(bundle->num_conns, ==, 0);
+		key_put(bundle->key);
+		kfree(bundle);
+	}
+
+	_leave("");
+}
+
+/*
+ * allocate a new connection
+ */
+static struct rxrpc_connection *rxrpc_alloc_connection(gfp_t gfp)
+{
+	struct rxrpc_connection *conn;
+
+	_enter("");
+
+	conn = kzalloc(sizeof(struct rxrpc_connection), gfp);
+	if (conn) {
+		INIT_WORK(&conn->processor, &rxrpc_process_connection);
+		INIT_LIST_HEAD(&conn->bundle_link);
+		conn->calls = RB_ROOT;
+		skb_queue_head_init(&conn->rx_queue);
+		rwlock_init(&conn->lock);
+		spin_lock_init(&conn->state_lock);
+		atomic_set(&conn->usage, 1);
+		conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
+		conn->avail_calls = RXRPC_MAXCALLS;
+		conn->size_align = 4;
+		conn->header_size = sizeof(struct rxrpc_header);
+	}
+
+	_leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
+	return conn;
+}
+
+/*
+ * assign a connection ID to a connection and add it to the transport's
+ * connection lookup tree
+ * - called with transport client lock held
+ */
+static void rxrpc_assign_connection_id(struct rxrpc_connection *conn)
+{
+	struct rxrpc_connection *xconn;
+	struct rb_node *parent, **p;
+	__be32 epoch;
+	u32 real_conn_id;
+
+	_enter("");
+
+	epoch = conn->epoch;
+
+	write_lock_bh(&conn->trans->conn_lock);
+
+	conn->trans->conn_idcounter += RXRPC_CID_INC;
+	if (conn->trans->conn_idcounter < RXRPC_CID_INC)
+		conn->trans->conn_idcounter = RXRPC_CID_INC;
+	real_conn_id = conn->trans->conn_idcounter;
+
+attempt_insertion:
+	parent = NULL;
+	p = &conn->trans->client_conns.rb_node;
+
+	while (*p) {
+		parent = *p;
+		xconn = rb_entry(parent, struct rxrpc_connection, node);
+
+		if (epoch < xconn->epoch)
+			p = &(*p)->rb_left;
+		else if (epoch > xconn->epoch)
+			p = &(*p)->rb_right;
+		else if (real_conn_id < xconn->real_conn_id)
+			p = &(*p)->rb_left;
+		else if (real_conn_id > xconn->real_conn_id)
+			p = &(*p)->rb_right;
+		else
+			goto id_exists;
+	}
+
+	/* we've found a suitable hole - arrange for this connection to occupy
+	 * it */
+	rb_link_node(&conn->node, parent, p);
+	rb_insert_color(&conn->node, &conn->trans->client_conns);
+
+	conn->real_conn_id = real_conn_id;
+	conn->cid = htonl(real_conn_id);
+	write_unlock_bh(&conn->trans->conn_lock);
+	_leave(" [CONNID %x CID %x]", real_conn_id, ntohl(conn->cid));
+	return;
+
+	/* we found a connection with the proposed ID - walk the tree from that
+	 * point looking for the next unused ID */
+id_exists:
+	for (;;) {
+		real_conn_id += RXRPC_CID_INC;
+		if (real_conn_id < RXRPC_CID_INC) {
+			real_conn_id = RXRPC_CID_INC;
+			conn->trans->conn_idcounter = real_conn_id;
+			goto attempt_insertion;
+		}
+
+		parent = rb_next(parent);
+		if (!parent)
+			goto attempt_insertion;
+
+		xconn = rb_entry(parent, struct rxrpc_connection, node);
+		if (epoch < xconn->epoch ||
+		    real_conn_id < xconn->real_conn_id)
+			goto attempt_insertion;
+	}
+}
+
+/*
+ * add a call to a connection's call-by-ID tree
+ */
+static void rxrpc_add_call_ID_to_conn(struct rxrpc_connection *conn,
+				      struct rxrpc_call *call)
+{
+	struct rxrpc_call *xcall;
+	struct rb_node *parent, **p;
+	__be32 call_id;
+
+	write_lock_bh(&conn->lock);
+
+	call_id = call->call_id;
+	p = &conn->calls.rb_node;
+	parent = NULL;
+	while (*p) {
+		parent = *p;
+		xcall = rb_entry(parent, struct rxrpc_call, conn_node);
+
+		if (call_id < xcall->call_id)
+			p = &(*p)->rb_left;
+		else if (call_id > xcall->call_id)
+			p = &(*p)->rb_right;
+		else
+			BUG();
+	}
+
+	rb_link_node(&call->conn_node, parent, p);
+	rb_insert_color(&call->conn_node, &conn->calls);
+
+	write_unlock_bh(&conn->lock);
+}
+
+/*
+ * connect a call on an exclusive connection
+ */
+static int rxrpc_connect_exclusive(struct rxrpc_sock *rx,
+				   struct rxrpc_transport *trans,
+				   __be16 service_id,
+				   struct rxrpc_call *call,
+				   gfp_t gfp)
+{
+	struct rxrpc_connection *conn;
+	int chan, ret;
+
+	_enter("");
+
+	conn = rx->conn;
+	if (!conn) {
+		/* not yet present - create a candidate for a new connection
+		 * and then redo the check */
+		conn = rxrpc_alloc_connection(gfp);
+		if (!conn) {
+			_leave(" = -ENOMEM");
+			return -ENOMEM;
+		}
+
+		conn->trans = trans;
+		conn->bundle = NULL;
+		conn->service_id = service_id;
+		conn->epoch = rxrpc_epoch;
+		conn->in_clientflag = 0;
+		conn->out_clientflag = RXRPC_CLIENT_INITIATED;
+		conn->cid = 0;
+		conn->state = RXRPC_CONN_CLIENT;
+		conn->avail_calls = RXRPC_MAXCALLS - 1;
+		conn->security_level = rx->min_sec_level;
+		conn->key = key_get(rx->key);
+
+		ret = rxrpc_init_client_conn_security(conn);
+		if (ret < 0) {
+			key_put(conn->key);
+			kfree(conn);
+			_leave(" = %d [key]", ret);
+			return ret;
+		}
+
+		write_lock_bh(&rxrpc_connection_lock);
+		list_add_tail(&conn->link, &rxrpc_connections);
+		write_unlock_bh(&rxrpc_connection_lock);
+
+		spin_lock(&trans->client_lock);
+		atomic_inc(&trans->usage);
+
+		_net("CONNECT EXCL new %d on TRANS %d",
+		     conn->debug_id, conn->trans->debug_id);
+
+		rxrpc_assign_connection_id(conn);
+		rx->conn = conn;
+	} else {
+		spin_lock(&trans->client_lock);
+	}
+
+	/* we've got a connection with a free channel and we can now attach the
+	 * call to it
+	 * - we're holding the transport's client lock
+	 * - we're holding a reference on the connection
+	 */
+	for (chan = 0; chan < RXRPC_MAXCALLS; chan++)
+		if (!conn->channels[chan])
+			goto found_channel;
+	goto no_free_channels;
+
+found_channel:
+	atomic_inc(&conn->usage);
+	conn->channels[chan] = call;
+	call->conn = conn;
+	call->channel = chan;
+	call->cid = conn->cid | htonl(chan);
+	call->call_id = htonl(++conn->call_counter);
+
+	_net("CONNECT client on conn %d chan %d as call %x",
+	     conn->debug_id, chan, ntohl(call->call_id));
+
+	spin_unlock(&trans->client_lock);
+
+	rxrpc_add_call_ID_to_conn(conn, call);
+	_leave(" = 0");
+	return 0;
+
+no_free_channels:
+	spin_unlock(&trans->client_lock);
+	_leave(" = -ENOSR");
+	return -ENOSR;
+}
+
+/*
+ * find a connection for a call
+ * - called in process context with IRQs enabled
+ */
+int rxrpc_connect_call(struct rxrpc_sock *rx,
+		       struct rxrpc_transport *trans,
+		       struct rxrpc_conn_bundle *bundle,
+		       struct rxrpc_call *call,
+		       gfp_t gfp)
+{
+	struct rxrpc_connection *conn, *candidate;
+	int chan, ret;
+
+	DECLARE_WAITQUEUE(myself, current);
+
+	_enter("%p,%lx,", rx, call->user_call_ID);
+
+	if (test_bit(RXRPC_SOCK_EXCLUSIVE_CONN, &rx->flags))
+		return rxrpc_connect_exclusive(rx, trans, bundle->service_id,
+					       call, gfp);
+
+	spin_lock(&trans->client_lock);
+	for (;;) {
+		/* see if the bundle has a call slot available */
+		if (!list_empty(&bundle->avail_conns)) {
+			_debug("avail");
+			conn = list_entry(bundle->avail_conns.next,
+					  struct rxrpc_connection,
+					  bundle_link);
+			if (conn->state >= RXRPC_CONN_REMOTELY_ABORTED) {
+				list_del_init(&conn->bundle_link);
+				bundle->num_conns--;
+				continue;
+			}
+			if (--conn->avail_calls == 0)
+				list_move(&conn->bundle_link,
+					  &bundle->busy_conns);
+			ASSERTCMP(conn->avail_calls, <, RXRPC_MAXCALLS);
+			ASSERT(conn->channels[0] == NULL ||
+			       conn->channels[1] == NULL ||
+			       conn->channels[2] == NULL ||
+			       conn->channels[3] == NULL);
+			atomic_inc(&conn->usage);
+			break;
+		}
+
+		if (!list_empty(&bundle->unused_conns)) {
+			_debug("unused");
+			conn = list_entry(bundle->unused_conns.next,
+					  struct rxrpc_connection,
+					  bundle_link);
+			if (conn->state >= RXRPC_CONN_REMOTELY_ABORTED) {
+				list_del_init(&conn->bundle_link);
+				bundle->num_conns--;
+				continue;
+			}
+			ASSERTCMP(conn->avail_calls, ==, RXRPC_MAXCALLS);
+			conn->avail_calls = RXRPC_MAXCALLS - 1;
+			ASSERT(conn->channels[0] == NULL &&
+			       conn->channels[1] == NULL &&
+			       conn->channels[2] == NULL &&
+			       conn->channels[3] == NULL);
+			atomic_inc(&conn->usage);
+			list_move(&conn->bundle_link, &bundle->avail_conns);
+			break;
+		}
+
+		/* need to allocate a new connection */
+		_debug("get new conn [%d]", bundle->num_conns);
+
+		spin_unlock(&trans->client_lock);
+
+		if (signal_pending(current))
+			goto interrupted;
+
+		if (bundle->num_conns >= 20) {
+			_debug("too many conns");
+
+			if (!(gfp & __GFP_WAIT)) {
+				_leave(" = -EAGAIN");
+				return -EAGAIN;
+			}
+
+			add_wait_queue(&bundle->chanwait, &myself);
+			for (;;) {
+				set_current_state(TASK_INTERRUPTIBLE);
+				if (bundle->num_conns < 20 ||
+				    !list_empty(&bundle->unused_conns) ||
+				    !list_empty(&bundle->avail_conns))
+					break;
+				if (signal_pending(current))
+					goto interrupted_dequeue;
+				schedule();
+			}
+			remove_wait_queue(&bundle->chanwait, &myself);
+			__set_current_state(TASK_RUNNING);
+			spin_lock(&trans->client_lock);
+			continue;
+		}
+
+		/* not yet present - create a candidate for a new connection and then
+		 * redo the check */
+		candidate = rxrpc_alloc_connection(gfp);
+		if (!candidate) {
+			_leave(" = -ENOMEM");
+			return -ENOMEM;
+		}
+
+		candidate->trans = trans;
+		candidate->bundle = bundle;
+		candidate->service_id = bundle->service_id;
+		candidate->epoch = rxrpc_epoch;
+		candidate->in_clientflag = 0;
+		candidate->out_clientflag = RXRPC_CLIENT_INITIATED;
+		candidate->cid = 0;
+		candidate->state = RXRPC_CONN_CLIENT;
+		candidate->avail_calls = RXRPC_MAXCALLS;
+		candidate->security_level = rx->min_sec_level;
+		candidate->key = key_get(bundle->key);
+
+		ret = rxrpc_init_client_conn_security(candidate);
+		if (ret < 0) {
+			key_put(candidate->key);
+			kfree(candidate);
+			_leave(" = %d [key]", ret);
+			return ret;
+		}
+
+		write_lock_bh(&rxrpc_connection_lock);
+		list_add_tail(&candidate->link, &rxrpc_connections);
+		write_unlock_bh(&rxrpc_connection_lock);
+
+		spin_lock(&trans->client_lock);
+
+		list_add(&candidate->bundle_link, &bundle->unused_conns);
+		bundle->num_conns++;
+		atomic_inc(&bundle->usage);
+		atomic_inc(&trans->usage);
+
+		_net("CONNECT new %d on TRANS %d",
+		     candidate->debug_id, candidate->trans->debug_id);
+
+		rxrpc_assign_connection_id(candidate);
+		if (candidate->security)
+			candidate->security->prime_packet_security(candidate);
+
+		/* leave the candidate lurking in zombie mode attached to the
+		 * bundle until we're ready for it */
+		rxrpc_put_connection(candidate);
+		candidate = NULL;
+	}
+
+	/* we've got a connection with a free channel and we can now attach the
+	 * call to it
+	 * - we're holding the transport's client lock
+	 * - we're holding a reference on the connection
+	 * - we're holding a reference on the bundle
+	 */
+	for (chan = 0; chan < RXRPC_MAXCALLS; chan++)
+		if (!conn->channels[chan])
+			goto found_channel;
+	ASSERT(conn->channels[0] == NULL ||
+	       conn->channels[1] == NULL ||
+	       conn->channels[2] == NULL ||
+	       conn->channels[3] == NULL);
+	BUG();
+
+found_channel:
+	conn->channels[chan] = call;
+	call->conn = conn;
+	call->channel = chan;
+	call->cid = conn->cid | htonl(chan);
+	call->call_id = htonl(++conn->call_counter);
+
+	_net("CONNECT client on conn %d chan %d as call %x",
+	     conn->debug_id, chan, ntohl(call->call_id));
+
+	ASSERTCMP(conn->avail_calls, <, RXRPC_MAXCALLS);
+	spin_unlock(&trans->client_lock);
+
+	rxrpc_add_call_ID_to_conn(conn, call);
+
+	_leave(" = 0");
+	return 0;
+
+interrupted_dequeue:
+	remove_wait_queue(&bundle->chanwait, &myself);
+	__set_current_state(TASK_RUNNING);
+interrupted:
+	_leave(" = -ERESTARTSYS");
+	return -ERESTARTSYS;
+}
+
+/*
+ * get a record of an incoming connection
+ */
+struct rxrpc_connection *
+rxrpc_incoming_connection(struct rxrpc_transport *trans,
+			  struct rxrpc_header *hdr,
+			  gfp_t gfp)
+{
+	struct rxrpc_connection *conn, *candidate = NULL;
+	struct rb_node *p, **pp;
+	const char *new = "old";
+	__be32 epoch;
+	u32 conn_id;
+
+	_enter("");
+
+	ASSERT(hdr->flags & RXRPC_CLIENT_INITIATED);
+
+	epoch = hdr->epoch;
+	conn_id = ntohl(hdr->cid) & RXRPC_CIDMASK;
+
+	/* search the connection list first */
+	read_lock_bh(&trans->conn_lock);
+
+	p = trans->server_conns.rb_node;
+	while (p) {
+		conn = rb_entry(p, struct rxrpc_connection, node);
+
+		_debug("maybe %x", conn->real_conn_id);
+
+		if (epoch < conn->epoch)
+			p = p->rb_left;
+		else if (epoch > conn->epoch)
+			p = p->rb_right;
+		else if (conn_id < conn->real_conn_id)
+			p = p->rb_left;
+		else if (conn_id > conn->real_conn_id)
+			p = p->rb_right;
+		else
+			goto found_extant_connection;
+	}
+	read_unlock_bh(&trans->conn_lock);
+
+	/* not yet present - create a candidate for a new record and then
+	 * redo the search */
+	candidate = rxrpc_alloc_connection(gfp);
+	if (!candidate) {
+		_leave(" = -ENOMEM");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	candidate->trans = trans;
+	candidate->epoch = hdr->epoch;
+	candidate->cid = hdr->cid & cpu_to_be32(RXRPC_CIDMASK);
+	candidate->service_id = hdr->serviceId;
+	candidate->security_ix = hdr->securityIndex;
+	candidate->in_clientflag = RXRPC_CLIENT_INITIATED;
+	candidate->out_clientflag = 0;
+	candidate->real_conn_id = conn_id;
+	candidate->state = RXRPC_CONN_SERVER;
+	if (candidate->service_id)
+		candidate->state = RXRPC_CONN_SERVER_UNSECURED;
+
+	write_lock_bh(&trans->conn_lock);
+
+	pp = &trans->server_conns.rb_node;
+	p = NULL;
+	while (*pp) {
+		p = *pp;
+		conn = rb_entry(p, struct rxrpc_connection, node);
+
+		if (epoch < conn->epoch)
+			pp = &(*pp)->rb_left;
+		else if (epoch > conn->epoch)
+			pp = &(*pp)->rb_right;
+		else if (conn_id < conn->real_conn_id)
+			pp = &(*pp)->rb_left;
+		else if (conn_id > conn->real_conn_id)
+			pp = &(*pp)->rb_right;
+		else
+			goto found_extant_second;
+	}
+
+	/* we can now add the new candidate to the list */
+	conn = candidate;
+	candidate = NULL;
+	rb_link_node(&conn->node, p, pp);
+	rb_insert_color(&conn->node, &trans->server_conns);
+	atomic_inc(&conn->trans->usage);
+
+	write_unlock_bh(&trans->conn_lock);
+
+	write_lock_bh(&rxrpc_connection_lock);
+	list_add_tail(&conn->link, &rxrpc_connections);
+	write_unlock_bh(&rxrpc_connection_lock);
+
+	new = "new";
+
+success:
+	_net("CONNECTION %s %d {%x}", new, conn->debug_id, conn->real_conn_id);
+
+	_leave(" = %p {u=%d}", conn, atomic_read(&conn->usage));
+	return conn;
+
+	/* we found the connection in the list immediately */
+found_extant_connection:
+	if (hdr->securityIndex != conn->security_ix) {
+		read_unlock_bh(&trans->conn_lock);
+		goto security_mismatch;
+	}
+	atomic_inc(&conn->usage);
+	read_unlock_bh(&trans->conn_lock);
+	goto success;
+
+	/* we found the connection on the second time through the list */
+found_extant_second:
+	if (hdr->securityIndex != conn->security_ix) {
+		write_unlock_bh(&trans->conn_lock);
+		goto security_mismatch;
+	}
+	atomic_inc(&conn->usage);
+	write_unlock_bh(&trans->conn_lock);
+	kfree(candidate);
+	goto success;
+
+security_mismatch:
+	kfree(candidate);
+	_leave(" = -EKEYREJECTED");
+	return ERR_PTR(-EKEYREJECTED);
+}
+
+/*
+ * find a connection based on transport and RxRPC connection ID for an incoming
+ * packet
+ */
+struct rxrpc_connection *rxrpc_find_connection(struct rxrpc_transport *trans,
+					       struct rxrpc_header *hdr)
+{
+	struct rxrpc_connection *conn;
+	struct rb_node *p;
+	__be32 epoch;
+	u32 conn_id;
+
+	_enter(",{%x,%x}", ntohl(hdr->cid), hdr->flags);
+
+	read_lock_bh(&trans->conn_lock);
+
+	conn_id = ntohl(hdr->cid) & RXRPC_CIDMASK;
+	epoch = hdr->epoch;
+
+	if (hdr->flags & RXRPC_CLIENT_INITIATED)
+		p = trans->server_conns.rb_node;
+	else
+		p = trans->client_conns.rb_node;
+
+	while (p) {
+		conn = rb_entry(p, struct rxrpc_connection, node);
+
+		_debug("maybe %x", conn->real_conn_id);
+
+		if (epoch < conn->epoch)
+			p = p->rb_left;
+		else if (epoch > conn->epoch)
+			p = p->rb_right;
+		else if (conn_id < conn->real_conn_id)
+			p = p->rb_left;
+		else if (conn_id > conn->real_conn_id)
+			p = p->rb_right;
+		else
+			goto found;
+	}
+
+	read_unlock_bh(&trans->conn_lock);
+	_leave(" = NULL");
+	return NULL;
+
+found:
+	atomic_inc(&conn->usage);
+	read_unlock_bh(&trans->conn_lock);
+	_leave(" = %p", conn);
+	return conn;
+}
+
+/*
+ * release a virtual connection
+ */
+void rxrpc_put_connection(struct rxrpc_connection *conn)
+{
+	_enter("%p{u=%d,d=%d}",
+	       conn, atomic_read(&conn->usage), conn->debug_id);
+
+	ASSERTCMP(atomic_read(&conn->usage), >, 0);
+
+	conn->put_time = get_seconds();
+	if (atomic_dec_and_test(&conn->usage)) {
+		_debug("zombie");
+		rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
+	}
+
+	_leave("");
+}
+
+/*
+ * destroy a virtual connection
+ */
+static void rxrpc_destroy_connection(struct rxrpc_connection *conn)
+{
+	_enter("%p{%d}", conn, atomic_read(&conn->usage));
+
+	ASSERTCMP(atomic_read(&conn->usage), ==, 0);
+
+	_net("DESTROY CONN %d", conn->debug_id);
+
+	if (conn->bundle)
+		rxrpc_put_bundle(conn->trans, conn->bundle);
+
+	ASSERT(RB_EMPTY_ROOT(&conn->calls));
+	rxrpc_purge_queue(&conn->rx_queue);
+
+	rxrpc_clear_conn_security(conn);
+	rxrpc_put_transport(conn->trans);
+	kfree(conn);
+	_leave("");
+}
+
+/*
+ * reap dead connections
+ */
+static void rxrpc_connection_reaper(struct work_struct *work)
+{
+	struct rxrpc_connection *conn, *_p;
+	unsigned long now, earliest, reap_time;
+
+	LIST_HEAD(graveyard);
+
+	_enter("");
+
+	now = get_seconds();
+	earliest = ULONG_MAX;
+
+	write_lock_bh(&rxrpc_connection_lock);
+	list_for_each_entry_safe(conn, _p, &rxrpc_connections, link) {
+		_debug("reap CONN %d { u=%d,t=%ld }",
+		       conn->debug_id, atomic_read(&conn->usage),
+		       (long) now - (long) conn->put_time);
+
+		if (likely(atomic_read(&conn->usage) > 0))
+			continue;
+
+		spin_lock(&conn->trans->client_lock);
+		write_lock(&conn->trans->conn_lock);
+		reap_time = conn->put_time + rxrpc_connection_expiry;
+
+		if (atomic_read(&conn->usage) > 0) {
+			;
+		} else if (reap_time <= now) {
+			list_move_tail(&conn->link, &graveyard);
+			if (conn->out_clientflag)
+				rb_erase(&conn->node,
+					 &conn->trans->client_conns);
+			else
+				rb_erase(&conn->node,
+					 &conn->trans->server_conns);
+			if (conn->bundle) {
+				list_del_init(&conn->bundle_link);
+				conn->bundle->num_conns--;
+			}
+
+		} else if (reap_time < earliest) {
+			earliest = reap_time;
+		}
+
+		write_unlock(&conn->trans->conn_lock);
+		spin_unlock(&conn->trans->client_lock);
+	}
+	write_unlock_bh(&rxrpc_connection_lock);
+
+	if (earliest != ULONG_MAX) {
+		_debug("reschedule reaper %ld", (long) earliest - now);
+		ASSERTCMP(earliest, >, now);
+		rxrpc_queue_delayed_work(&rxrpc_connection_reap,
+					 (earliest - now) * HZ);
+	}
+
+	/* then destroy all those pulled out */
+	while (!list_empty(&graveyard)) {
+		conn = list_entry(graveyard.next, struct rxrpc_connection,
+				  link);
+		list_del_init(&conn->link);
+
+		ASSERTCMP(atomic_read(&conn->usage), ==, 0);
+		rxrpc_destroy_connection(conn);
+	}
+
+	_leave("");
+}
+
+/*
+ * preemptively destroy all the connection records rather than waiting for them
+ * to time out
+ */
+void __exit rxrpc_destroy_all_connections(void)
+{
+	_enter("");
+
+	rxrpc_connection_expiry = 0;
+	cancel_delayed_work(&rxrpc_connection_reap);
+	rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
+
+	_leave("");
+}