1 files changed, 309 insertions, 0 deletions
diff --git a/net/rxrpc/ar-local.c b/net/rxrpc/ar-local.c
new file mode 100644
index 00000000000..fe03f71f17d
--- /dev/null
+++ b/net/rxrpc/ar-local.c
@@ -0,0 +1,309 @@
+/* AF_RXRPC local endpoint 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 LIST_HEAD(rxrpc_locals);
+DEFINE_RWLOCK(rxrpc_local_lock);
+static DECLARE_RWSEM(rxrpc_local_sem);
+static DECLARE_WAIT_QUEUE_HEAD(rxrpc_local_wq);
+
+static void rxrpc_destroy_local(struct work_struct *work);
+
+/*
+ * allocate a new local
+ */
+static
+struct rxrpc_local *rxrpc_alloc_local(struct sockaddr_rxrpc *srx)
+{
+	struct rxrpc_local *local;
+
+	local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL);
+	if (local) {
+		INIT_WORK(&local->destroyer, &rxrpc_destroy_local);
+		INIT_WORK(&local->acceptor, &rxrpc_accept_incoming_calls);
+		INIT_WORK(&local->rejecter, &rxrpc_reject_packets);
+		INIT_LIST_HEAD(&local->services);
+		INIT_LIST_HEAD(&local->link);
+		init_rwsem(&local->defrag_sem);
+		skb_queue_head_init(&local->accept_queue);
+		skb_queue_head_init(&local->reject_queue);
+		spin_lock_init(&local->lock);
+		rwlock_init(&local->services_lock);
+		atomic_set(&local->usage, 1);
+		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_sem writelocked
+ */
+static int rxrpc_create_local(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(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");
+			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;
+	}
+
+	write_lock_bh(&rxrpc_local_lock);
+	list_add(&local->link, &rxrpc_locals);
+	write_unlock_bh(&rxrpc_local_lock);
+
+	/* 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_UDP_error_report;
+	_leave(" = 0");
+	return 0;
+
+error:
+	local->socket->ops->shutdown(local->socket, 2);
+	local->socket->sk->sk_user_data = NULL;
+	sock_release(local->socket);
+	local->socket = NULL;
+
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * create a new local endpoint using the specified UDP address
+ */
+struct rxrpc_local *rxrpc_lookup_local(struct sockaddr_rxrpc *srx)
+{
+	struct rxrpc_local *local;
+	int ret;
+
+	_enter("{%d,%u,%u.%u.%u.%u+%hu}",
+	       srx->transport_type,
+	       srx->transport.family,
+	       NIPQUAD(srx->transport.sin.sin_addr),
+	       ntohs(srx->transport.sin.sin_port));
+
+	down_write(&rxrpc_local_sem);
+
+	/* see if we have a suitable local local endpoint already */
+	read_lock_bh(&rxrpc_local_lock);
+
+	list_for_each_entry(local, &rxrpc_locals, link) {
+		_debug("CMP {%d,%u,%u.%u.%u.%u+%hu}",
+		       local->srx.transport_type,
+		       local->srx.transport.family,
+		       NIPQUAD(local->srx.transport.sin.sin_addr),
+		       ntohs(local->srx.transport.sin.sin_port));
+
+		if (local->srx.transport_type != srx->transport_type ||
+		    local->srx.transport.family != srx->transport.family)
+			continue;
+
+		switch (srx->transport.family) {
+		case AF_INET:
+			if (local->srx.transport.sin.sin_port !=
+			    srx->transport.sin.sin_port)
+				continue;
+			if (memcmp(&local->srx.transport.sin.sin_addr,
+				   &srx->transport.sin.sin_addr,
+				   sizeof(struct in_addr)) != 0)
+				continue;
+			goto found_local;
+
+		default:
+			BUG();
+		}
+	}
+
+	read_unlock_bh(&rxrpc_local_lock);
+
+	/* we didn't find one, so we need to create one */
+	local = rxrpc_alloc_local(srx);
+	if (!local) {
+		up_write(&rxrpc_local_sem);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	ret = rxrpc_create_local(local);
+	if (ret < 0) {
+		up_write(&rxrpc_local_sem);
+		kfree(local);
+		_leave(" = %d", ret);
+		return ERR_PTR(ret);
+	}
+
+	up_write(&rxrpc_local_sem);
+
+	_net("LOCAL new %d {%d,%u,%u.%u.%u.%u+%hu}",
+	     local->debug_id,
+	     local->srx.transport_type,
+	     local->srx.transport.family,
+	     NIPQUAD(local->srx.transport.sin.sin_addr),
+	     ntohs(local->srx.transport.sin.sin_port));
+
+	_leave(" = %p [new]", local);
+	return local;
+
+found_local:
+	rxrpc_get_local(local);
+	read_unlock_bh(&rxrpc_local_lock);
+	up_write(&rxrpc_local_sem);
+
+	_net("LOCAL old %d {%d,%u,%u.%u.%u.%u+%hu}",
+	     local->debug_id,
+	     local->srx.transport_type,
+	     local->srx.transport.family,
+	     NIPQUAD(local->srx.transport.sin.sin_addr),
+	     ntohs(local->srx.transport.sin.sin_port));
+
+	_leave(" = %p [reuse]", local);
+	return local;
+}
+
+/*
+ * release a local endpoint
+ */
+void rxrpc_put_local(struct rxrpc_local *local)
+{
+	_enter("%p{u=%d}", local, atomic_read(&local->usage));
+
+	ASSERTCMP(atomic_read(&local->usage), >, 0);
+
+	/* to prevent a race, the decrement and the dequeue must be effectively
+	 * atomic */
+	write_lock_bh(&rxrpc_local_lock);
+	if (unlikely(atomic_dec_and_test(&local->usage))) {
+		_debug("destroy local");
+		rxrpc_queue_work(&local->destroyer);
+	}
+	write_unlock_bh(&rxrpc_local_lock);
+	_leave("");
+}
+
+/*
+ * destroy a local endpoint
+ */
+static void rxrpc_destroy_local(struct work_struct *work)
+{
+	struct rxrpc_local *local =
+		container_of(work, struct rxrpc_local, destroyer);
+
+	_enter("%p{%d}", local, atomic_read(&local->usage));
+
+	down_write(&rxrpc_local_sem);
+
+	write_lock_bh(&rxrpc_local_lock);
+	if (atomic_read(&local->usage) > 0) {
+		write_unlock_bh(&rxrpc_local_lock);
+		up_read(&rxrpc_local_sem);
+		_leave(" [resurrected]");
+		return;
+	}
+
+	list_del(&local->link);
+	local->socket->sk->sk_user_data = NULL;
+	write_unlock_bh(&rxrpc_local_lock);
+
+	downgrade_write(&rxrpc_local_sem);
+
+	ASSERT(list_empty(&local->services));
+	ASSERT(!work_pending(&local->acceptor));
+	ASSERT(!work_pending(&local->rejecter));
+
+	/* finish cleaning up the local descriptor */
+	rxrpc_purge_queue(&local->accept_queue);
+	rxrpc_purge_queue(&local->reject_queue);
+	local->socket->ops->shutdown(local->socket, 2);
+	sock_release(local->socket);
+
+	up_read(&rxrpc_local_sem);
+
+	_net("DESTROY LOCAL %d", local->debug_id);
+	kfree(local);
+
+	if (list_empty(&rxrpc_locals))
+		wake_up_all(&rxrpc_local_wq);
+
+	_leave("");
+}
+
+/*
+ * preemptively destroy all local local endpoint rather than waiting for
+ * them to be destroyed
+ */
+void __exit rxrpc_destroy_all_locals(void)
+{
+	DECLARE_WAITQUEUE(myself,current);
+
+	_enter("");
+
+	/* we simply have to wait for them to go away */
+	if (!list_empty(&rxrpc_locals)) {
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		add_wait_queue(&rxrpc_local_wq, &myself);
+
+		while (!list_empty(&rxrpc_locals)) {
+			schedule();
+			set_current_state(TASK_UNINTERRUPTIBLE);
+		}
+
+		remove_wait_queue(&rxrpc_local_wq, &myself);
+		set_current_state(TASK_RUNNING);
+	}
+
+	_leave("");
+}