Linux-libre 4.8.2-gnupck-4.8.2-gnu

1 files changed, 390 insertions, 0 deletions

diff --git a/net/rxrpc/local_object.c b/net/rxrpc/local_object.c
new file mode 100644
index 000000000..a753796fb
--- /dev/null
+++ b/net/rxrpc/local_object.c
@@ -0,0 +1,390 @@
+/* Local endpoint object management
+ *
+ * Copyright (C) 2016 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 Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/net.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/udp.h>
+#include <linux/ip.h>
+#include <linux/hashtable.h>
+#include <net/sock.h>
+#include <net/af_rxrpc.h>
+#include "ar-internal.h"
+
+static void rxrpc_local_processor(struct work_struct *);
+static void rxrpc_local_rcu(struct rcu_head *);
+
+static DEFINE_MUTEX(rxrpc_local_mutex);
+static LIST_HEAD(rxrpc_local_endpoints);
+
+/*
+ * Compare a local to an address.  Return -ve, 0 or +ve to indicate less than,
+ * same or greater than.
+ *
+ * We explicitly don't compare the RxRPC service ID as we want to reject
+ * conflicting uses by differing services.  Further, we don't want to share
+ * addresses with different options (IPv6), so we don't compare those bits
+ * either.
+ */
+static long rxrpc_local_cmp_key(const struct rxrpc_local *local,
+				const struct sockaddr_rxrpc *srx)
+{
+	long diff;
+
+	diff = ((local->srx.transport_type - srx->transport_type) ?:
+		(local->srx.transport_len - srx->transport_len) ?:
+		(local->srx.transport.family - srx->transport.family));
+	if (diff != 0)
+		return diff;
+
+	switch (srx->transport.family) {
+	case AF_INET:
+		/* If the choice of UDP port is left up to the transport, then
+		 * the endpoint record doesn't match.
+		 */
+		return ((u16 __force)local->srx.transport.sin.sin_port -
+			(u16 __force)srx->transport.sin.sin_port) ?:
+			memcmp(&local->srx.transport.sin.sin_addr,
+			       &srx->transport.sin.sin_addr,
+			       sizeof(struct in_addr));
+	default:
+		BUG();
+	}
+}
+
+/*
+ * Allocate a new local endpoint.
+ */
+static struct rxrpc_local *rxrpc_alloc_local(const struct sockaddr_rxrpc *srx)
+{
+	struct rxrpc_local *local;
+
+	local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL);
+	if (local) {
+		atomic_set(&local->usage, 1);
+		INIT_LIST_HEAD(&local->link);
+		INIT_WORK(&local->processor, rxrpc_local_processor);
+		INIT_LIST_HEAD(&local->services);
+		init_rwsem(&local->defrag_sem);
+		skb_queue_head_init(&local->accept_queue);
+		skb_queue_head_init(&local->reject_queue);
+		skb_queue_head_init(&local->event_queue);
+		local->client_conns = RB_ROOT;
+		spin_lock_init(&local->client_conns_lock);
+		spin_lock_init(&local->lock);
+		rwlock_init(&local->services_lock);
+		local->debug_id = atomic_inc_return(&rxrpc_debug_id);
+		memcpy(&local->srx, srx, sizeof(*srx));
+	}
+
+	_leave(" = %p", local);
+	return local;
+}
+
+/*
+ * create the local socket
+ * - must be called with rxrpc_local_mutex locked
+ */
+static int rxrpc_open_socket(struct rxrpc_local *local)
+{
+	struct sock *sock;
+	int ret, opt;
+
+	_enter("%p{%d}", local, local->srx.transport_type);
+
+	/* create a socket to represent the local endpoint */
+	ret = sock_create_kern(&init_net, PF_INET, local->srx.transport_type,
+			       IPPROTO_UDP, &local->socket);
+	if (ret < 0) {
+		_leave(" = %d [socket]", ret);
+		return ret;
+	}
+
+	/* if a local address was supplied then bind it */
+	if (local->srx.transport_len > sizeof(sa_family_t)) {
+		_debug("bind");
+		ret = kernel_bind(local->socket,
+				  (struct sockaddr *)&local->srx.transport,
+				  local->srx.transport_len);
+		if (ret < 0) {
+			_debug("bind failed %d", ret);
+			goto error;
+		}
+	}
+
+	/* we want to receive ICMP errors */
+	opt = 1;
+	ret = kernel_setsockopt(local->socket, SOL_IP, IP_RECVERR,
+				(char *) &opt, sizeof(opt));
+	if (ret < 0) {
+		_debug("setsockopt failed");
+		goto error;
+	}
+
+	/* we want to set the don't fragment bit */
+	opt = IP_PMTUDISC_DO;
+	ret = kernel_setsockopt(local->socket, SOL_IP, IP_MTU_DISCOVER,
+				(char *) &opt, sizeof(opt));
+	if (ret < 0) {
+		_debug("setsockopt failed");
+		goto error;
+	}
+
+	/* set the socket up */
+	sock = local->socket->sk;
+	sock->sk_user_data	= local;
+	sock->sk_data_ready	= rxrpc_data_ready;
+	sock->sk_error_report	= rxrpc_error_report;
+	_leave(" = 0");
+	return 0;
+
+error:
+	kernel_sock_shutdown(local->socket, SHUT_RDWR);
+	local->socket->sk->sk_user_data = NULL;
+	sock_release(local->socket);
+	local->socket = NULL;
+
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * Look up or create a new local endpoint using the specified local address.
+ */
+struct rxrpc_local *rxrpc_lookup_local(const struct sockaddr_rxrpc *srx)
+{
+	struct rxrpc_local *local;
+	struct list_head *cursor;
+	const char *age;
+	long diff;
+	int ret;
+
+	if (srx->transport.family == AF_INET) {
+		_enter("{%d,%u,%pI4+%hu}",
+		       srx->transport_type,
+		       srx->transport.family,
+		       &srx->transport.sin.sin_addr,
+		       ntohs(srx->transport.sin.sin_port));
+	} else {
+		_enter("{%d,%u}",
+		       srx->transport_type,
+		       srx->transport.family);
+		return ERR_PTR(-EAFNOSUPPORT);
+	}
+
+	mutex_lock(&rxrpc_local_mutex);
+
+	for (cursor = rxrpc_local_endpoints.next;
+	     cursor != &rxrpc_local_endpoints;
+	     cursor = cursor->next) {
+		local = list_entry(cursor, struct rxrpc_local, link);
+
+		diff = rxrpc_local_cmp_key(local, srx);
+		if (diff < 0)
+			continue;
+		if (diff > 0)
+			break;
+
+		/* Services aren't allowed to share transport sockets, so
+		 * reject that here.  It is possible that the object is dying -
+		 * but it may also still have the local transport address that
+		 * we want bound.
+		 */
+		if (srx->srx_service) {
+			local = NULL;
+			goto addr_in_use;
+		}
+
+		/* Found a match.  We replace a dying object.  Attempting to
+		 * bind the transport socket may still fail if we're attempting
+		 * to use a local address that the dying object is still using.
+		 */
+		if (!rxrpc_get_local_maybe(local)) {
+			cursor = cursor->next;
+			list_del_init(&local->link);
+			break;
+		}
+
+		age = "old";
+		goto found;
+	}
+
+	local = rxrpc_alloc_local(srx);
+	if (!local)
+		goto nomem;
+
+	ret = rxrpc_open_socket(local);
+	if (ret < 0)
+		goto sock_error;
+
+	list_add_tail(&local->link, cursor);
+	age = "new";
+
+found:
+	mutex_unlock(&rxrpc_local_mutex);
+
+	_net("LOCAL %s %d {%d,%u,%pI4+%hu}",
+	     age,
+	     local->debug_id,
+	     local->srx.transport_type,
+	     local->srx.transport.family,
+	     &local->srx.transport.sin.sin_addr,
+	     ntohs(local->srx.transport.sin.sin_port));
+
+	_leave(" = %p", local);
+	return local;
+
+nomem:
+	ret = -ENOMEM;
+sock_error:
+	mutex_unlock(&rxrpc_local_mutex);
+	kfree(local);
+	_leave(" = %d", ret);
+	return ERR_PTR(ret);
+
+addr_in_use:
+	mutex_unlock(&rxrpc_local_mutex);
+	_leave(" = -EADDRINUSE");
+	return ERR_PTR(-EADDRINUSE);
+}
+
+/*
+ * A local endpoint reached its end of life.
+ */
+void __rxrpc_put_local(struct rxrpc_local *local)
+{
+	_enter("%d", local->debug_id);
+	rxrpc_queue_work(&local->processor);
+}
+
+/*
+ * Destroy a local endpoint's socket and then hand the record to RCU to dispose
+ * of.
+ *
+ * Closing the socket cannot be done from bottom half context or RCU callback
+ * context because it might sleep.
+ */
+static void rxrpc_local_destroyer(struct rxrpc_local *local)
+{
+	struct socket *socket = local->socket;
+
+	_enter("%d", local->debug_id);
+
+	/* We can get a race between an incoming call packet queueing the
+	 * processor again and the work processor starting the destruction
+	 * process which will shut down the UDP socket.
+	 */
+	if (local->dead) {
+		_leave(" [already dead]");
+		return;
+	}
+	local->dead = true;
+
+	mutex_lock(&rxrpc_local_mutex);
+	list_del_init(&local->link);
+	mutex_unlock(&rxrpc_local_mutex);
+
+	ASSERT(RB_EMPTY_ROOT(&local->client_conns));
+	ASSERT(list_empty(&local->services));
+
+	if (socket) {
+		local->socket = NULL;
+		kernel_sock_shutdown(socket, SHUT_RDWR);
+		socket->sk->sk_user_data = NULL;
+		sock_release(socket);
+	}
+
+	/* At this point, there should be no more packets coming in to the
+	 * local endpoint.
+	 */
+	rxrpc_purge_queue(&local->accept_queue);
+	rxrpc_purge_queue(&local->reject_queue);
+	rxrpc_purge_queue(&local->event_queue);
+
+	_debug("rcu local %d", local->debug_id);
+	call_rcu(&local->rcu, rxrpc_local_rcu);
+}
+
+/*
+ * Process events on an endpoint
+ */
+static void rxrpc_local_processor(struct work_struct *work)
+{
+	struct rxrpc_local *local =
+		container_of(work, struct rxrpc_local, processor);
+	bool again;
+
+	_enter("%d", local->debug_id);
+
+	do {
+		again = false;
+		if (atomic_read(&local->usage) == 0)
+			return rxrpc_local_destroyer(local);
+
+		if (!skb_queue_empty(&local->accept_queue)) {
+			rxrpc_accept_incoming_calls(local);
+			again = true;
+		}
+
+		if (!skb_queue_empty(&local->reject_queue)) {
+			rxrpc_reject_packets(local);
+			again = true;
+		}
+
+		if (!skb_queue_empty(&local->event_queue)) {
+			rxrpc_process_local_events(local);
+			again = true;
+		}
+	} while (again);
+}
+
+/*
+ * Destroy a local endpoint after the RCU grace period expires.
+ */
+static void rxrpc_local_rcu(struct rcu_head *rcu)
+{
+	struct rxrpc_local *local = container_of(rcu, struct rxrpc_local, rcu);
+
+	_enter("%d", local->debug_id);
+
+	ASSERT(!work_pending(&local->processor));
+
+	_net("DESTROY LOCAL %d", local->debug_id);
+	kfree(local);
+	_leave("");
+}
+
+/*
+ * Verify the local endpoint list is empty by this point.
+ */
+void __exit rxrpc_destroy_all_locals(void)
+{
+	struct rxrpc_local *local;
+
+	_enter("");
+
+	flush_workqueue(rxrpc_workqueue);
+
+	if (!list_empty(&rxrpc_local_endpoints)) {
+		mutex_lock(&rxrpc_local_mutex);
+		list_for_each_entry(local, &rxrpc_local_endpoints, link) {
+			pr_err("AF_RXRPC: Leaked local %p {%d}\n",
+			       local, atomic_read(&local->usage));
+		}
+		mutex_unlock(&rxrpc_local_mutex);
+		BUG();
+	}
+
+	rcu_barrier();
+}