/*

   * Copyright (c) 2006, 2017 Oracle and/or its affiliates. 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_conn_path *cp;

  	struct rds_tcp_connection *tc;

  	read_lock_bh(&sk->sk_callback_lock);

  	cp = sk->sk_user_data;
  	if (!cp) {

  		state_change = sk->sk_state_change;
  		goto out;
  	}

  	tc = cp->cp_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:

  		/* Force the peer to reconnect so that we have the
  		 * TCP ports going from <smaller-ip>.<transient> to
  		 * <larger-ip>.<RDS_TCP_PORT>. We avoid marking the
  		 * RDS connection as RDS_CONN_UP until the reconnect,
  		 * to avoid RDS datagram loss.
  		 */

  		if (rds_addr_cmp(&cp->cp_conn->c_laddr,
  				 &cp->cp_conn->c_faddr) >= 0 &&

  		    rds_conn_path_transition(cp, RDS_CONN_CONNECTING,
  					     RDS_CONN_ERROR)) {

  			rds_conn_path_drop(cp, false);

  		} else {
  			rds_connect_path_complete(cp, RDS_CONN_CONNECTING);
  		}

  		break;
  	case TCP_CLOSE_WAIT:
  	case TCP_CLOSE:

  		rds_conn_path_drop(cp, false);

  	default:
  		break;

  	}
  out:

  	read_unlock_bh(&sk->sk_callback_lock);

  	state_change(sk);
  }

  int rds_tcp_conn_path_connect(struct rds_conn_path *cp)

  {
  	struct socket *sock = NULL;

  	struct sockaddr_in6 sin6;

  	struct sockaddr_in sin;
  	struct sockaddr *addr;
  	int addrlen;

  	bool isv6;

  	int ret;

  	struct rds_connection *conn = cp->cp_conn;
  	struct rds_tcp_connection *tc = cp->cp_transport_data;

  	/* for multipath rds,we only trigger the connection after
  	 * the handshake probe has determined the number of paths.
  	 */
  	if (cp->cp_index > 0 && cp->cp_conn->c_npaths < 2)
  		return -EAGAIN;

  	mutex_lock(&tc->t_conn_path_lock);

  	if (rds_conn_path_up(cp)) {

  		mutex_unlock(&tc->t_conn_path_lock);

  		return 0;
  	}

  	if (ipv6_addr_v4mapped(&conn->c_laddr)) {
  		ret = sock_create_kern(rds_conn_net(conn), PF_INET,
  				       SOCK_STREAM, IPPROTO_TCP, &sock);
  		isv6 = false;
  	} else {
  		ret = sock_create_kern(rds_conn_net(conn), PF_INET6,
  				       SOCK_STREAM, IPPROTO_TCP, &sock);
  		isv6 = true;
  	}

  	if (ret < 0)
  		goto out;
  
  	rds_tcp_tune(sock);

  	if (isv6) {
  		sin6.sin6_family = AF_INET6;
  		sin6.sin6_addr = conn->c_laddr;
  		sin6.sin6_port = 0;
  		sin6.sin6_flowinfo = 0;
  		sin6.sin6_scope_id = conn->c_dev_if;
  		addr = (struct sockaddr *)&sin6;
  		addrlen = sizeof(sin6);
  	} else {
  		sin.sin_family = AF_INET;
  		sin.sin_addr.s_addr = conn->c_laddr.s6_addr32[3];
  		sin.sin_port = 0;
  		addr = (struct sockaddr *)&sin;
  		addrlen = sizeof(sin);
  	}

  	ret = sock->ops->bind(sock, addr, addrlen);

  	if (ret) {

  		rdsdebug("bind failed with %d at address %pI6c
  ",

  			 ret, &conn->c_laddr);

  		goto out;
  	}

  	if (isv6) {
  		sin6.sin6_family = AF_INET6;
  		sin6.sin6_addr = conn->c_faddr;
  		sin6.sin6_port = htons(RDS_TCP_PORT);
  		sin6.sin6_flowinfo = 0;
  		sin6.sin6_scope_id = conn->c_dev_if;
  		addr = (struct sockaddr *)&sin6;
  		addrlen = sizeof(sin6);
  	} else {
  		sin.sin_family = AF_INET;
  		sin.sin_addr.s_addr = conn->c_faddr.s6_addr32[3];
  		sin.sin_port = htons(RDS_TCP_PORT);
  		addr = (struct sockaddr *)&sin;
  		addrlen = sizeof(sin);
  	}

  
  	/*
  	 * once we call connect() we can start getting callbacks and they
  	 * own the socket
  	 */

  	rds_tcp_set_callbacks(sock, cp);

  	ret = sock->ops->connect(sock, addr, addrlen, O_NONBLOCK);

  	rdsdebug("connect to address %pI6c returned %d
  ", &conn->c_faddr, ret);

  	if (ret == -EINPROGRESS)
  		ret = 0;

  	if (ret == 0) {
  		rds_tcp_keepalive(sock);

  		sock = NULL;

  	} else {

  		rds_tcp_restore_callbacks(sock, cp->cp_transport_data);

  	}

  
  out:

  	mutex_unlock(&tc->t_conn_path_lock);

  	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_path_shutdown(struct rds_conn_path *cp)

  {

  	struct rds_tcp_connection *tc = cp->cp_transport_data;

  	struct socket *sock = tc->t_sock;

  	rdsdebug("shutting down conn %p tc %p sock %p
  ",
  		 cp->cp_conn, tc, sock);

  
  	if (sock) {

  		if (rds_destroy_pending(cp->cp_conn))

  			rds_tcp_set_linger(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;
  }