Fixed MTP to work with TWRP

net/tipc/server.c

@@ -0,0 +1,600 @@
+/*
+ * net/tipc/server.c: TIPC server infrastructure
+ *
+ * Copyright (c) 2012-2013, Wind River Systems
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the names of the copyright holders nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "server.h"
+#include "core.h"
+#include <net/sock.h>
+
+/* Number of messages to send before rescheduling */
+#define MAX_SEND_MSG_COUNT	25
+#define MAX_RECV_MSG_COUNT	25
+#define CF_CONNECTED		1
+
+#define sock2con(x) ((struct tipc_conn *)(x)->sk_user_data)
+
+/**
+ * struct tipc_conn - TIPC connection structure
+ * @kref: reference counter to connection object
+ * @conid: connection identifier
+ * @sock: socket handler associated with connection
+ * @flags: indicates connection state
+ * @server: pointer to connected server
+ * @rwork: receive work item
+ * @usr_data: user-specified field
+ * @rx_action: what to do when connection socket is active
+ * @outqueue: pointer to first outbound message in queue
+ * @outqueue_lock: control access to the outqueue
+ * @outqueue: list of connection objects for its server
+ * @swork: send work item
+ */
+struct tipc_conn {
+	struct kref kref;
+	int conid;
+	struct socket *sock;
+	unsigned long flags;
+	struct tipc_server *server;
+	struct work_struct rwork;
+	int (*rx_action) (struct tipc_conn *con);
+	void *usr_data;
+	struct list_head outqueue;
+	spinlock_t outqueue_lock;
+	struct work_struct swork;
+};
+
+/* An entry waiting to be sent */
+struct outqueue_entry {
+	struct list_head list;
+	struct kvec iov;
+	struct sockaddr_tipc dest;
+};
+
+static void tipc_recv_work(struct work_struct *work);
+static void tipc_send_work(struct work_struct *work);
+static void tipc_clean_outqueues(struct tipc_conn *con);
+
+static void tipc_conn_kref_release(struct kref *kref)
+{
+	struct tipc_conn *con = container_of(kref, struct tipc_conn, kref);
+
+	if (con->sock) {
+		tipc_sock_release_local(con->sock);
+		con->sock = NULL;
+	}
+
+	tipc_clean_outqueues(con);
+	kfree(con);
+}
+
+static void conn_put(struct tipc_conn *con)
+{
+	kref_put(&con->kref, tipc_conn_kref_release);
+}
+
+static void conn_get(struct tipc_conn *con)
+{
+	kref_get(&con->kref);
+}
+
+static struct tipc_conn *tipc_conn_lookup(struct tipc_server *s, int conid)
+{
+	struct tipc_conn *con;
+
+	spin_lock_bh(&s->idr_lock);
+	con = idr_find(&s->conn_idr, conid);
+	if (con)
+		conn_get(con);
+	spin_unlock_bh(&s->idr_lock);
+	return con;
+}
+
+static void sock_data_ready(struct sock *sk)
+{
+	struct tipc_conn *con;
+
+	read_lock(&sk->sk_callback_lock);
+	con = sock2con(sk);
+	if (con && test_bit(CF_CONNECTED, &con->flags)) {
+		conn_get(con);
+		if (!queue_work(con->server->rcv_wq, &con->rwork))
+			conn_put(con);
+	}
+	read_unlock(&sk->sk_callback_lock);
+}
+
+static void sock_write_space(struct sock *sk)
+{
+	struct tipc_conn *con;
+
+	read_lock(&sk->sk_callback_lock);
+	con = sock2con(sk);
+	if (con && test_bit(CF_CONNECTED, &con->flags)) {
+		conn_get(con);
+		if (!queue_work(con->server->send_wq, &con->swork))
+			conn_put(con);
+	}
+	read_unlock(&sk->sk_callback_lock);
+}
+
+static void tipc_register_callbacks(struct socket *sock, struct tipc_conn *con)
+{
+	struct sock *sk = sock->sk;
+
+	write_lock_bh(&sk->sk_callback_lock);
+
+	sk->sk_data_ready = sock_data_ready;
+	sk->sk_write_space = sock_write_space;
+	sk->sk_user_data = con;
+
+	con->sock = sock;
+
+	write_unlock_bh(&sk->sk_callback_lock);
+}
+
+static void tipc_unregister_callbacks(struct tipc_conn *con)
+{
+	struct sock *sk = con->sock->sk;
+
+	write_lock_bh(&sk->sk_callback_lock);
+	sk->sk_user_data = NULL;
+	write_unlock_bh(&sk->sk_callback_lock);
+}
+
+static void tipc_close_conn(struct tipc_conn *con)
+{
+	struct tipc_server *s = con->server;
+
+	if (test_and_clear_bit(CF_CONNECTED, &con->flags)) {
+		if (con->conid)
+			s->tipc_conn_shutdown(con->conid, con->usr_data);
+
+		spin_lock_bh(&s->idr_lock);
+		idr_remove(&s->conn_idr, con->conid);
+		s->idr_in_use--;
+		spin_unlock_bh(&s->idr_lock);
+
+		tipc_unregister_callbacks(con);
+
+		/* We shouldn't flush pending works as we may be in the
+		 * thread. In fact the races with pending rx/tx work structs
+		 * are harmless for us here as we have already deleted this
+		 * connection from server connection list and set
+		 * sk->sk_user_data to 0 before releasing connection object.
+		 */
+		kernel_sock_shutdown(con->sock, SHUT_RDWR);
+
+		conn_put(con);
+	}
+}
+
+static struct tipc_conn *tipc_alloc_conn(struct tipc_server *s)
+{
+	struct tipc_conn *con;
+	int ret;
+
+	con = kzalloc(sizeof(struct tipc_conn), GFP_ATOMIC);
+	if (!con)
+		return ERR_PTR(-ENOMEM);
+
+	kref_init(&con->kref);
+	INIT_LIST_HEAD(&con->outqueue);
+	spin_lock_init(&con->outqueue_lock);
+	INIT_WORK(&con->swork, tipc_send_work);
+	INIT_WORK(&con->rwork, tipc_recv_work);
+
+	spin_lock_bh(&s->idr_lock);
+	ret = idr_alloc(&s->conn_idr, con, 0, 0, GFP_ATOMIC);
+	if (ret < 0) {
+		kfree(con);
+		spin_unlock_bh(&s->idr_lock);
+		return ERR_PTR(-ENOMEM);
+	}
+	con->conid = ret;
+	s->idr_in_use++;
+	spin_unlock_bh(&s->idr_lock);
+
+	set_bit(CF_CONNECTED, &con->flags);
+	con->server = s;
+
+	return con;
+}
+
+static int tipc_receive_from_sock(struct tipc_conn *con)
+{
+	struct msghdr msg = {};
+	struct tipc_server *s = con->server;
+	struct sockaddr_tipc addr;
+	struct kvec iov;
+	void *buf;
+	int ret;
+
+	buf = kmem_cache_alloc(s->rcvbuf_cache, GFP_ATOMIC);
+	if (!buf) {
+		ret = -ENOMEM;
+		goto out_close;
+	}
+
+	iov.iov_base = buf;
+	iov.iov_len = s->max_rcvbuf_size;
+	msg.msg_name = &addr;
+	ret = kernel_recvmsg(con->sock, &msg, &iov, 1, iov.iov_len,
+			     MSG_DONTWAIT);
+	if (ret <= 0) {
+		kmem_cache_free(s->rcvbuf_cache, buf);
+		goto out_close;
+	}
+
+	s->tipc_conn_recvmsg(con->conid, &addr, con->usr_data, buf, ret);
+
+	kmem_cache_free(s->rcvbuf_cache, buf);
+
+	return 0;
+
+out_close:
+	if (ret != -EWOULDBLOCK)
+		tipc_close_conn(con);
+	else if (ret == 0)
+		/* Don't return success if we really got EOF */
+		ret = -EAGAIN;
+
+	return ret;
+}
+
+static int tipc_accept_from_sock(struct tipc_conn *con)
+{
+	struct tipc_server *s = con->server;
+	struct socket *sock = con->sock;
+	struct socket *newsock;
+	struct tipc_conn *newcon;
+	int ret;
+
+	ret = tipc_sock_accept_local(sock, &newsock, O_NONBLOCK);
+	if (ret < 0)
+		return ret;
+
+	newcon = tipc_alloc_conn(con->server);
+	if (IS_ERR(newcon)) {
+		ret = PTR_ERR(newcon);
+		sock_release(newsock);
+		return ret;
+	}
+
+	newcon->rx_action = tipc_receive_from_sock;
+	tipc_register_callbacks(newsock, newcon);
+
+	/* Notify that new connection is incoming */
+	newcon->usr_data = s->tipc_conn_new(newcon->conid);
+
+	/* Wake up receive process in case of 'SYN+' message */
+	newsock->sk->sk_data_ready(newsock->sk);
+	return ret;
+}
+
+static struct socket *tipc_create_listen_sock(struct tipc_conn *con)
+{
+	struct tipc_server *s = con->server;
+	struct socket *sock = NULL;
+	int ret;
+
+	ret = tipc_sock_create_local(s->type, &sock);
+	if (ret < 0)
+		return NULL;
+	ret = kernel_setsockopt(sock, SOL_TIPC, TIPC_IMPORTANCE,
+				(char *)&s->imp, sizeof(s->imp));
+	if (ret < 0)
+		goto create_err;
+	ret = kernel_bind(sock, (struct sockaddr *)s->saddr, sizeof(*s->saddr));
+	if (ret < 0)
+		goto create_err;
+
+	switch (s->type) {
+	case SOCK_STREAM:
+	case SOCK_SEQPACKET:
+		con->rx_action = tipc_accept_from_sock;
+
+		ret = kernel_listen(sock, 0);
+		if (ret < 0)
+			goto create_err;
+		break;
+	case SOCK_DGRAM:
+	case SOCK_RDM:
+		con->rx_action = tipc_receive_from_sock;
+		break;
+	default:
+		pr_err("Unknown socket type %d\n", s->type);
+		goto create_err;
+	}
+	return sock;
+
+create_err:
+	sock_release(sock);
+	con->sock = NULL;
+	return NULL;
+}
+
+static int tipc_open_listening_sock(struct tipc_server *s)
+{
+	struct socket *sock;
+	struct tipc_conn *con;
+
+	con = tipc_alloc_conn(s);
+	if (IS_ERR(con))
+		return PTR_ERR(con);
+
+	sock = tipc_create_listen_sock(con);
+	if (!sock) {
+		idr_remove(&s->conn_idr, con->conid);
+		s->idr_in_use--;
+		kfree(con);
+		return -EINVAL;
+	}
+
+	tipc_register_callbacks(sock, con);
+	return 0;
+}
+
+static struct outqueue_entry *tipc_alloc_entry(void *data, int len)
+{
+	struct outqueue_entry *entry;
+	void *buf;
+
+	entry = kmalloc(sizeof(struct outqueue_entry), GFP_ATOMIC);
+	if (!entry)
+		return NULL;
+
+	buf = kmalloc(len, GFP_ATOMIC);
+	if (!buf) {
+		kfree(entry);
+		return NULL;
+	}
+
+	memcpy(buf, data, len);
+	entry->iov.iov_base = buf;
+	entry->iov.iov_len = len;
+
+	return entry;
+}
+
+static void tipc_free_entry(struct outqueue_entry *e)
+{
+	kfree(e->iov.iov_base);
+	kfree(e);
+}
+
+static void tipc_clean_outqueues(struct tipc_conn *con)
+{
+	struct outqueue_entry *e, *safe;
+
+	spin_lock_bh(&con->outqueue_lock);
+	list_for_each_entry_safe(e, safe, &con->outqueue, list) {
+		list_del(&e->list);
+		tipc_free_entry(e);
+	}
+	spin_unlock_bh(&con->outqueue_lock);
+}
+
+int tipc_conn_sendmsg(struct tipc_server *s, int conid,
+		      struct sockaddr_tipc *addr, void *data, size_t len)
+{
+	struct outqueue_entry *e;
+	struct tipc_conn *con;
+
+	con = tipc_conn_lookup(s, conid);
+	if (!con)
+		return -EINVAL;
+
+	e = tipc_alloc_entry(data, len);
+	if (!e) {
+		conn_put(con);
+		return -ENOMEM;
+	}
+
+	if (addr)
+		memcpy(&e->dest, addr, sizeof(struct sockaddr_tipc));
+
+	spin_lock_bh(&con->outqueue_lock);
+	list_add_tail(&e->list, &con->outqueue);
+	spin_unlock_bh(&con->outqueue_lock);
+
+	if (test_bit(CF_CONNECTED, &con->flags)) {
+		if (!queue_work(s->send_wq, &con->swork))
+			conn_put(con);
+	} else {
+		conn_put(con);
+	}
+	return 0;
+}
+
+void tipc_conn_terminate(struct tipc_server *s, int conid)
+{
+	struct tipc_conn *con;
+
+	con = tipc_conn_lookup(s, conid);
+	if (con) {
+		tipc_close_conn(con);
+		conn_put(con);
+	}
+}
+
+static void tipc_send_to_sock(struct tipc_conn *con)
+{
+	int count = 0;
+	struct tipc_server *s = con->server;
+	struct outqueue_entry *e;
+	struct msghdr msg;
+	int ret;
+
+	spin_lock_bh(&con->outqueue_lock);
+	while (1) {
+		e = list_entry(con->outqueue.next, struct outqueue_entry,
+			       list);
+		if ((struct list_head *) e == &con->outqueue)
+			break;
+		spin_unlock_bh(&con->outqueue_lock);
+
+		memset(&msg, 0, sizeof(msg));
+		msg.msg_flags = MSG_DONTWAIT;
+
+		if (s->type == SOCK_DGRAM || s->type == SOCK_RDM) {
+			msg.msg_name = &e->dest;
+			msg.msg_namelen = sizeof(struct sockaddr_tipc);
+		}
+		ret = kernel_sendmsg(con->sock, &msg, &e->iov, 1,
+				     e->iov.iov_len);
+		if (ret == -EWOULDBLOCK || ret == 0) {
+			cond_resched();
+			goto out;
+		} else if (ret < 0) {
+			goto send_err;
+		}
+
+		/* Don't starve users filling buffers */
+		if (++count >= MAX_SEND_MSG_COUNT) {
+			cond_resched();
+			count = 0;
+		}
+
+		spin_lock_bh(&con->outqueue_lock);
+		list_del(&e->list);
+		tipc_free_entry(e);
+	}
+	spin_unlock_bh(&con->outqueue_lock);
+out:
+	return;
+
+send_err:
+	tipc_close_conn(con);
+}
+
+static void tipc_recv_work(struct work_struct *work)
+{
+	struct tipc_conn *con = container_of(work, struct tipc_conn, rwork);
+	int count = 0;
+
+	while (test_bit(CF_CONNECTED, &con->flags)) {
+		if (con->rx_action(con))
+			break;
+
+		/* Don't flood Rx machine */
+		if (++count >= MAX_RECV_MSG_COUNT) {
+			cond_resched();
+			count = 0;
+		}
+	}
+	conn_put(con);
+}
+
+static void tipc_send_work(struct work_struct *work)
+{
+	struct tipc_conn *con = container_of(work, struct tipc_conn, swork);
+
+	if (test_bit(CF_CONNECTED, &con->flags))
+		tipc_send_to_sock(con);
+
+	conn_put(con);
+}
+
+static void tipc_work_stop(struct tipc_server *s)
+{
+	destroy_workqueue(s->rcv_wq);
+	destroy_workqueue(s->send_wq);
+}
+
+static int tipc_work_start(struct tipc_server *s)
+{
+	s->rcv_wq = alloc_workqueue("tipc_rcv", WQ_UNBOUND, 1);
+	if (!s->rcv_wq) {
+		pr_err("can't start tipc receive workqueue\n");
+		return -ENOMEM;
+	}
+
+	s->send_wq = alloc_workqueue("tipc_send", WQ_UNBOUND, 1);
+	if (!s->send_wq) {
+		pr_err("can't start tipc send workqueue\n");
+		destroy_workqueue(s->rcv_wq);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+int tipc_server_start(struct tipc_server *s)
+{
+	int ret;
+
+	spin_lock_init(&s->idr_lock);
+	idr_init(&s->conn_idr);
+	s->idr_in_use = 0;
+
+	s->rcvbuf_cache = kmem_cache_create(s->name, s->max_rcvbuf_size,
+					    0, SLAB_HWCACHE_ALIGN, NULL);
+	if (!s->rcvbuf_cache)
+		return -ENOMEM;
+
+	ret = tipc_work_start(s);
+	if (ret < 0) {
+		kmem_cache_destroy(s->rcvbuf_cache);
+		return ret;
+	}
+	ret = tipc_open_listening_sock(s);
+	if (ret < 0) {
+		tipc_work_stop(s);
+		kmem_cache_destroy(s->rcvbuf_cache);
+		return ret;
+	}
+	return ret;
+}
+
+void tipc_server_stop(struct tipc_server *s)
+{
+	struct tipc_conn *con;
+	int total = 0;
+	int id;
+
+	spin_lock_bh(&s->idr_lock);
+	for (id = 0; total < s->idr_in_use; id++) {
+		con = idr_find(&s->conn_idr, id);
+		if (con) {
+			total++;
+			spin_unlock_bh(&s->idr_lock);
+			tipc_close_conn(con);
+			spin_lock_bh(&s->idr_lock);
+		}
+	}
+	spin_unlock_bh(&s->idr_lock);
+
+	tipc_work_stop(s);
+	kmem_cache_destroy(s->rcvbuf_cache);
+	idr_destroy(&s->conn_idr);
+}