/*
   * Copyright (c) 2006 Oracle.  All rights reserved.
   *
   * This software is available to you under a choice of one of two
   * licenses.  You may choose to be licensed under the terms of the GNU
   * General Public License (GPL) Version 2, available from the file
   * COPYING in the main directory of this source tree, or the
   * OpenIB.org BSD license below:
   *
   *     Redistribution and use in source and binary forms, with or
   *     without modification, are permitted provided that the following
   *     conditions are met:
   *
   *      - Redistributions of source code must retain the above
   *        copyright notice, this list of conditions and the following
   *        disclaimer.
   *
   *      - 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.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
   * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
   * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   *
   */
  #include <linux/kernel.h>
  #include <linux/in.h>
  #include <net/tcp.h>
  
  #include "rds.h"
  #include "tcp.h"
  
  void rds_tcp_state_change(struct sock *sk)
  {
  	void (*state_change)(struct sock *sk);
  	struct rds_connection *conn;
  	struct rds_tcp_connection *tc;
  
  	read_lock(&sk->sk_callback_lock);
  	conn = sk->sk_user_data;
  	if (!conn) {
  		state_change = sk->sk_state_change;
  		goto out;
  	}
  	tc = conn->c_transport_data;
  	state_change = tc->t_orig_state_change;
  
  	rdsdebug("sock %p state_change to %d
  ", tc->t_sock, sk->sk_state);
  
  	switch(sk->sk_state) {
  		/* ignore connecting sockets as they make progress */
  		case TCP_SYN_SENT:
  		case TCP_SYN_RECV:
  			break;
  		case TCP_ESTABLISHED:
  			rds_connect_complete(conn);
  			break;
  		case TCP_CLOSE:
  			rds_conn_drop(conn);
  		default:
  			break;
  	}
  out:
  	read_unlock(&sk->sk_callback_lock);
  	state_change(sk);
  }
  
  int rds_tcp_conn_connect(struct rds_connection *conn)
  {
  	struct socket *sock = NULL;
  	struct sockaddr_in src, dest;
  	int ret;
  
  	ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
  	if (ret < 0)
  		goto out;
  
  	rds_tcp_tune(sock);
  
  	src.sin_family = AF_INET;
  	src.sin_addr.s_addr = (__force u32)conn->c_laddr;
  	src.sin_port = (__force u16)htons(0);
  
  	ret = sock->ops->bind(sock, (struct sockaddr *)&src, sizeof(src));
  	if (ret) {
  		rdsdebug("bind failed with %d at address %pI4
  ",
  			 ret, &conn->c_laddr);
  		goto out;
  	}
  
  	dest.sin_family = AF_INET;
  	dest.sin_addr.s_addr = (__force u32)conn->c_faddr;
  	dest.sin_port = (__force u16)htons(RDS_TCP_PORT);
  
  	/*
  	 * once we call connect() we can start getting callbacks and they
  	 * own the socket
  	 */
  	rds_tcp_set_callbacks(sock, conn);
  	ret = sock->ops->connect(sock, (struct sockaddr *)&dest, sizeof(dest),
  				 O_NONBLOCK);
  	sock = NULL;
  
  	rdsdebug("connect to address %pI4 returned %d
  ", &conn->c_faddr, ret);
  	if (ret == -EINPROGRESS)
  		ret = 0;
  
  out:
  	if (sock)
  		sock_release(sock);
  	return ret;
  }
  
  /*
   * Before killing the tcp socket this needs to serialize with callbacks.  The
   * caller has already grabbed the sending sem so we're serialized with other
   * senders.
   *
   * TCP calls the callbacks with the sock lock so we hold it while we reset the
   * callbacks to those set by TCP.  Our callbacks won't execute again once we
   * hold the sock lock.
   */
  void rds_tcp_conn_shutdown(struct rds_connection *conn)
  {
  	struct rds_tcp_connection *tc = conn->c_transport_data;
  	struct socket *sock = tc->t_sock;
  
  	rdsdebug("shutting down conn %p tc %p sock %p
  ", conn, tc, sock);
  
  	if (sock) {
  		sock->ops->shutdown(sock, RCV_SHUTDOWN | SEND_SHUTDOWN);
  		lock_sock(sock->sk);
  		rds_tcp_restore_callbacks(sock, tc); /* tc->tc_sock = NULL */
  
  		release_sock(sock->sk);
  		sock_release(sock);
  	}
  
  	if (tc->t_tinc) {
  		rds_inc_put(&tc->t_tinc->ti_inc);
  		tc->t_tinc = NULL;
  	}
  	tc->t_tinc_hdr_rem = sizeof(struct rds_header);
  	tc->t_tinc_data_rem = 0;
  }