/*

   * net/tipc/socket.c: TIPC socket API

   *

   * Copyright (c) 2001-2007, 2012-2016, Ericsson AB

   * Copyright (c) 2004-2008, 2010-2013, 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 <linux/rhashtable.h>

  #include <linux/sched/signal.h>

  #include "core.h"

  #include "name_table.h"

  #include "node.h"

  #include "link.h"

  #include "name_distr.h"

  #include "socket.h"

  #include "bcast.h"

  #include "netlink.h"

  #define CONN_TIMEOUT_DEFAULT	8000	/* default connect timeout = 8s */

  #define CONN_PROBING_INTERVAL	msecs_to_jiffies(3600000)  /* [ms] => 1 h */

  #define TIPC_FWD_MSG		1

  #define TIPC_MAX_PORT		0xffffffff
  #define TIPC_MIN_PORT		1

  #define TIPC_ACK_RATE		4       /* ACK at 1/4 of of rcv window size */

  enum {
  	TIPC_LISTEN = TCP_LISTEN,

  	TIPC_ESTABLISHED = TCP_ESTABLISHED,

  	TIPC_OPEN = TCP_CLOSE,

  	TIPC_DISCONNECTING = TCP_CLOSE_WAIT,

  	TIPC_CONNECTING = TCP_SYN_SENT,

  };

  /**
   * struct tipc_sock - TIPC socket structure
   * @sk: socket - interacts with 'port' and with user via the socket API

   * @conn_type: TIPC type used when connection was established
   * @conn_instance: TIPC instance used when connection was established
   * @published: non-zero if port has one or more associated names
   * @max_pkt: maximum packet size "hint" used when building messages sent by port

   * @portid: unique port identity in TIPC socket hash table

   * @phdr: preformatted message header used when sending messages

   * #cong_links: list of congested links

   * @publications: list of publications for port

   * @blocking_link: address of the congested link we are currently sleeping on

   * @pub_count: total # of publications port has made during its lifetime
   * @probing_state:

   * @conn_timeout: the time we can wait for an unresponded setup request
   * @dupl_rcvcnt: number of bytes counted twice, in both backlog and rcv queue

   * @cong_link_cnt: number of congested links

   * @sent_unacked: # messages sent by socket, and not yet acked by peer
   * @rcv_unacked: # messages read by user, but not yet acked back to peer

   * @peer: 'connected' peer for dgram/rdm

   * @node: hash table node

   * @mc_method: cookie for use between socket and broadcast layer

   * @rcu: rcu struct for tipc_sock

   */
  struct tipc_sock {
  	struct sock sk;

  	u32 conn_type;
  	u32 conn_instance;
  	int published;
  	u32 max_pkt;

  	u32 portid;

  	struct tipc_msg phdr;

  	struct list_head cong_links;

  	struct list_head publications;
  	u32 pub_count;

  	uint conn_timeout;
  	atomic_t dupl_rcvcnt;

  	bool probe_unacked;

  	u16 cong_link_cnt;

  	u16 snt_unacked;
  	u16 snd_win;

  	u16 peer_caps;

  	u16 rcv_unacked;
  	u16 rcv_win;

  	struct sockaddr_tipc peer;

  	struct rhash_head node;

  	struct tipc_mc_method mc_method;

  	struct rcu_head rcu;

  };

  static int tipc_backlog_rcv(struct sock *sk, struct sk_buff *skb);

  static void tipc_data_ready(struct sock *sk);

  static void tipc_write_space(struct sock *sk);

  static void tipc_sock_destruct(struct sock *sk);

  static int tipc_release(struct socket *sock);

  static int tipc_accept(struct socket *sock, struct socket *new_sock, int flags,
  		       bool kern);

  static void tipc_sk_timeout(unsigned long data);

  static int tipc_sk_publish(struct tipc_sock *tsk, uint scope,

  			   struct tipc_name_seq const *seq);

  static int tipc_sk_withdraw(struct tipc_sock *tsk, uint scope,

  			    struct tipc_name_seq const *seq);

  static struct tipc_sock *tipc_sk_lookup(struct net *net, u32 portid);

  static int tipc_sk_insert(struct tipc_sock *tsk);
  static void tipc_sk_remove(struct tipc_sock *tsk);

  static int __tipc_sendstream(struct socket *sock, struct msghdr *m, size_t dsz);

  static int __tipc_sendmsg(struct socket *sock, struct msghdr *m, size_t dsz);

  static const struct proto_ops packet_ops;
  static const struct proto_ops stream_ops;
  static const struct proto_ops msg_ops;

  static struct proto tipc_proto;

  static const struct rhashtable_params tsk_rht_params;

  static u32 tsk_own_node(struct tipc_sock *tsk)
  {
  	return msg_prevnode(&tsk->phdr);
  }

  static u32 tsk_peer_node(struct tipc_sock *tsk)

  {

  	return msg_destnode(&tsk->phdr);

  }

  static u32 tsk_peer_port(struct tipc_sock *tsk)

  {

  	return msg_destport(&tsk->phdr);

  }

  static  bool tsk_unreliable(struct tipc_sock *tsk)

  {

  	return msg_src_droppable(&tsk->phdr) != 0;

  }

  static void tsk_set_unreliable(struct tipc_sock *tsk, bool unreliable)

  {

  	msg_set_src_droppable(&tsk->phdr, unreliable ? 1 : 0);

  }

  static bool tsk_unreturnable(struct tipc_sock *tsk)

  {

  	return msg_dest_droppable(&tsk->phdr) != 0;

  }

  static void tsk_set_unreturnable(struct tipc_sock *tsk, bool unreturnable)

  {

  	msg_set_dest_droppable(&tsk->phdr, unreturnable ? 1 : 0);

  }

  static int tsk_importance(struct tipc_sock *tsk)

  {

  	return msg_importance(&tsk->phdr);

  }

  static int tsk_set_importance(struct tipc_sock *tsk, int imp)

  {
  	if (imp > TIPC_CRITICAL_IMPORTANCE)
  		return -EINVAL;

  	msg_set_importance(&tsk->phdr, (u32)imp);

  	return 0;
  }

  static struct tipc_sock *tipc_sk(const struct sock *sk)
  {
  	return container_of(sk, struct tipc_sock, sk);
  }

  static bool tsk_conn_cong(struct tipc_sock *tsk)

  {

  	return tsk->snt_unacked > tsk->snd_win;

  }
  
  /* tsk_blocks(): translate a buffer size in bytes to number of
   * advertisable blocks, taking into account the ratio truesize(len)/len
   * We can trust that this ratio is always < 4 for len >= FLOWCTL_BLK_SZ
   */
  static u16 tsk_adv_blocks(int len)
  {
  	return len / FLOWCTL_BLK_SZ / 4;
  }
  
  /* tsk_inc(): increment counter for sent or received data
   * - If block based flow control is not supported by peer we
   *   fall back to message based ditto, incrementing the counter
   */
  static u16 tsk_inc(struct tipc_sock *tsk, int msglen)
  {
  	if (likely(tsk->peer_caps & TIPC_BLOCK_FLOWCTL))
  		return ((msglen / FLOWCTL_BLK_SZ) + 1);
  	return 1;

  }

  /**

   * tsk_advance_rx_queue - discard first buffer in socket receive queue

   *
   * Caller must hold socket lock

   */

  static void tsk_advance_rx_queue(struct sock *sk)

  {

  	kfree_skb(__skb_dequeue(&sk->sk_receive_queue));

  }

  /* tipc_sk_respond() : send response message back to sender
   */
  static void tipc_sk_respond(struct sock *sk, struct sk_buff *skb, int err)
  {
  	u32 selector;
  	u32 dnode;
  	u32 onode = tipc_own_addr(sock_net(sk));
  
  	if (!tipc_msg_reverse(onode, &skb, err))
  		return;
  
  	dnode = msg_destnode(buf_msg(skb));
  	selector = msg_origport(buf_msg(skb));
  	tipc_node_xmit_skb(sock_net(sk), skb, dnode, selector);
  }

  /**

   * tsk_rej_rx_queue - reject all buffers in socket receive queue

   *
   * Caller must hold socket lock

   */

  static void tsk_rej_rx_queue(struct sock *sk)

  {

  	struct sk_buff *skb;

  	while ((skb = __skb_dequeue(&sk->sk_receive_queue)))
  		tipc_sk_respond(sk, skb, TIPC_ERR_NO_PORT);

  }

  static bool tipc_sk_connected(struct sock *sk)
  {

  	return sk->sk_state == TIPC_ESTABLISHED;

  }

  /* tipc_sk_type_connectionless - check if the socket is datagram socket
   * @sk: socket
   *
   * Returns true if connection less, false otherwise
   */
  static bool tipc_sk_type_connectionless(struct sock *sk)
  {
  	return sk->sk_type == SOCK_RDM || sk->sk_type == SOCK_DGRAM;
  }

  /* tsk_peer_msg - verify if message was sent by connected port's peer

   *
   * Handles cases where the node's network address has changed from
   * the default of <0.0.0> to its configured setting.
   */

  static bool tsk_peer_msg(struct tipc_sock *tsk, struct tipc_msg *msg)

  {

  	struct sock *sk = &tsk->sk;
  	struct tipc_net *tn = net_generic(sock_net(sk), tipc_net_id);

  	u32 peer_port = tsk_peer_port(tsk);

  	u32 orig_node;
  	u32 peer_node;

  	if (unlikely(!tipc_sk_connected(sk)))

  		return false;
  
  	if (unlikely(msg_origport(msg) != peer_port))
  		return false;
  
  	orig_node = msg_orignode(msg);

  	peer_node = tsk_peer_node(tsk);

  
  	if (likely(orig_node == peer_node))
  		return true;

  	if (!orig_node && (peer_node == tn->own_addr))

  		return true;

  	if (!peer_node && (orig_node == tn->own_addr))

  		return true;
  
  	return false;
  }

  /* tipc_set_sk_state - set the sk_state of the socket
   * @sk: socket
   *
   * Caller must hold socket lock
   *
   * Returns 0 on success, errno otherwise
   */
  static int tipc_set_sk_state(struct sock *sk, int state)
  {

  	int oldsk_state = sk->sk_state;

  	int res = -EINVAL;
  
  	switch (state) {

  	case TIPC_OPEN:
  		res = 0;
  		break;

  	case TIPC_LISTEN:

  	case TIPC_CONNECTING:

  		if (oldsk_state == TIPC_OPEN)

  			res = 0;
  		break;

  	case TIPC_ESTABLISHED:

  		if (oldsk_state == TIPC_CONNECTING ||

  		    oldsk_state == TIPC_OPEN)

  			res = 0;
  		break;

  	case TIPC_DISCONNECTING:

  		if (oldsk_state == TIPC_CONNECTING ||

  		    oldsk_state == TIPC_ESTABLISHED)
  			res = 0;
  		break;

  	}
  
  	if (!res)
  		sk->sk_state = state;
  
  	return res;
  }

  static int tipc_sk_sock_err(struct socket *sock, long *timeout)
  {
  	struct sock *sk = sock->sk;
  	int err = sock_error(sk);
  	int typ = sock->type;
  
  	if (err)
  		return err;
  	if (typ == SOCK_STREAM || typ == SOCK_SEQPACKET) {
  		if (sk->sk_state == TIPC_DISCONNECTING)
  			return -EPIPE;
  		else if (!tipc_sk_connected(sk))
  			return -ENOTCONN;
  	}
  	if (!*timeout)
  		return -EAGAIN;
  	if (signal_pending(current))
  		return sock_intr_errno(*timeout);
  
  	return 0;
  }

  #define tipc_wait_for_cond(sock_, timeo_, condition_)			       \
  ({                                                                             \
  	struct sock *sk_;						       \
  	int rc_;							       \
  									       \
  	while ((rc_ = !(condition_))) {					       \
  		DEFINE_WAIT_FUNC(wait_, woken_wake_function);	               \
  		sk_ = (sock_)->sk;					       \
  		rc_ = tipc_sk_sock_err((sock_), timeo_);		       \
  		if (rc_)						       \
  			break;						       \
  		prepare_to_wait(sk_sleep(sk_), &wait_, TASK_INTERRUPTIBLE);    \
  		release_sock(sk_);					       \
  		*(timeo_) = wait_woken(&wait_, TASK_INTERRUPTIBLE, *(timeo_)); \
  		sched_annotate_sleep();				               \
  		lock_sock(sk_);						       \
  		remove_wait_queue(sk_sleep(sk_), &wait_);		       \
  	}								       \
  	rc_;								       \

  })

  /**

   * tipc_sk_create - create a TIPC socket

   * @net: network namespace (must be default network)

   * @sock: pre-allocated socket structure
   * @protocol: protocol indicator (must be 0)

   * @kern: caused by kernel or by userspace?

   *

   * This routine creates additional data structures used by the TIPC socket,
   * initializes them, and links them together.

   *
   * Returns 0 on success, errno otherwise
   */

  static int tipc_sk_create(struct net *net, struct socket *sock,
  			  int protocol, int kern)

  {

  	struct tipc_net *tn;

  	const struct proto_ops *ops;

  	struct sock *sk;

  	struct tipc_sock *tsk;

  	struct tipc_msg *msg;

  
  	/* Validate arguments */

  	if (unlikely(protocol != 0))
  		return -EPROTONOSUPPORT;

  	switch (sock->type) {
  	case SOCK_STREAM:

  		ops = &stream_ops;

  		break;
  	case SOCK_SEQPACKET:

  		ops = &packet_ops;

  		break;
  	case SOCK_DGRAM:

  	case SOCK_RDM:

  		ops = &msg_ops;

  		break;

  	default:

  		return -EPROTOTYPE;

  	}

  	/* Allocate socket's protocol area */

  	sk = sk_alloc(net, AF_TIPC, GFP_KERNEL, &tipc_proto, kern);

  	if (sk == NULL)

  		return -ENOMEM;

  	tsk = tipc_sk(sk);

  	tsk->max_pkt = MAX_PKT_DEFAULT;

  	INIT_LIST_HEAD(&tsk->publications);

  	INIT_LIST_HEAD(&tsk->cong_links);

  	msg = &tsk->phdr;

  	tn = net_generic(sock_net(sk), tipc_net_id);

  	/* Finish initializing socket data structures */

  	sock->ops = ops;

  	sock_init_data(sock, sk);

  	tipc_set_sk_state(sk, TIPC_OPEN);

  	if (tipc_sk_insert(tsk)) {

  		pr_warn("Socket create failed; port number exhausted
  ");

  		return -EINVAL;
  	}

  
  	/* Ensure tsk is visible before we read own_addr. */
  	smp_mb();
  
  	tipc_msg_init(tn->own_addr, msg, TIPC_LOW_IMPORTANCE, TIPC_NAMED_MSG,
  		      NAMED_H_SIZE, 0);

  	msg_set_origport(msg, tsk->portid);

  	setup_timer(&sk->sk_timer, tipc_sk_timeout, (unsigned long)tsk);

  	sk->sk_shutdown = 0;

  	sk->sk_backlog_rcv = tipc_backlog_rcv;

  	sk->sk_rcvbuf = sysctl_tipc_rmem[1];

  	sk->sk_data_ready = tipc_data_ready;
  	sk->sk_write_space = tipc_write_space;

  	sk->sk_destruct = tipc_sock_destruct;

  	tsk->conn_timeout = CONN_TIMEOUT_DEFAULT;
  	atomic_set(&tsk->dupl_rcvcnt, 0);

  	/* Start out with safe limits until we receive an advertised window */
  	tsk->snd_win = tsk_adv_blocks(RCVBUF_MIN);
  	tsk->rcv_win = tsk->snd_win;

  	if (tipc_sk_type_connectionless(sk)) {

  		tsk_set_unreturnable(tsk, true);

  		if (sock->type == SOCK_DGRAM)

  			tsk_set_unreliable(tsk, true);

  	}

  	return 0;
  }

  static void tipc_sk_callback(struct rcu_head *head)
  {
  	struct tipc_sock *tsk = container_of(head, struct tipc_sock, rcu);
  
  	sock_put(&tsk->sk);
  }

  /* Caller should hold socket lock for the socket. */
  static void __tipc_shutdown(struct socket *sock, int error)
  {
  	struct sock *sk = sock->sk;
  	struct tipc_sock *tsk = tipc_sk(sk);
  	struct net *net = sock_net(sk);

  	long timeout = CONN_TIMEOUT_DEFAULT;

  	u32 dnode = tsk_peer_node(tsk);
  	struct sk_buff *skb;

  	/* Avoid that hi-prio shutdown msgs bypass msgs in link wakeup queue */
  	tipc_wait_for_cond(sock, &timeout, (!tsk->cong_link_cnt &&
  					    !tsk_conn_cong(tsk)));

  	/* Reject all unreceived messages, except on an active connection
  	 * (which disconnects locally & sends a 'FIN+' to peer).
  	 */
  	while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
  		if (TIPC_SKB_CB(skb)->bytes_read) {
  			kfree_skb(skb);

  			continue;

  		}

  		if (!tipc_sk_type_connectionless(sk) &&
  		    sk->sk_state != TIPC_DISCONNECTING) {
  			tipc_set_sk_state(sk, TIPC_DISCONNECTING);
  			tipc_node_remove_conn(net, dnode, tsk->portid);
  		}
  		tipc_sk_respond(sk, skb, error);

  	}

  
  	if (tipc_sk_type_connectionless(sk))
  		return;

  	if (sk->sk_state != TIPC_DISCONNECTING) {
  		skb = tipc_msg_create(TIPC_CRITICAL_IMPORTANCE,
  				      TIPC_CONN_MSG, SHORT_H_SIZE, 0, dnode,
  				      tsk_own_node(tsk), tsk_peer_port(tsk),
  				      tsk->portid, error);
  		if (skb)
  			tipc_node_xmit_skb(net, skb, dnode, tsk->portid);

  		tipc_node_remove_conn(net, dnode, tsk->portid);
  		tipc_set_sk_state(sk, TIPC_DISCONNECTING);

  	}
  }

  /**

   * tipc_release - destroy a TIPC socket

   * @sock: socket to destroy
   *
   * This routine cleans up any messages that are still queued on the socket.
   * For DGRAM and RDM socket types, all queued messages are rejected.
   * For SEQPACKET and STREAM socket types, the first message is rejected
   * and any others are discarded.  (If the first message on a STREAM socket
   * is partially-read, it is discarded and the next one is rejected instead.)

   *

   * NOTE: Rejected messages are not necessarily returned to the sender!  They
   * are returned or discarded according to the "destination droppable" setting
   * specified for the message by the sender.
   *
   * Returns 0 on success, errno otherwise
   */

  static int tipc_release(struct socket *sock)

  {

  	struct sock *sk = sock->sk;

  	struct tipc_sock *tsk;

  	/*
  	 * Exit if socket isn't fully initialized (occurs when a failed accept()
  	 * releases a pre-allocated child socket that was never used)
  	 */

  	if (sk == NULL)

  		return 0;

  	tsk = tipc_sk(sk);

  	lock_sock(sk);

  	__tipc_shutdown(sock, TIPC_ERR_NO_PORT);
  	sk->sk_shutdown = SHUTDOWN_MASK;

  	tipc_sk_withdraw(tsk, 0, NULL);

  	sk_stop_timer(sk, &sk->sk_timer);

  	tipc_sk_remove(tsk);

  	/* Reject any messages that accumulated in backlog queue */

  	release_sock(sk);

  	u32_list_purge(&tsk->cong_links);
  	tsk->cong_link_cnt = 0;

  	call_rcu(&tsk->rcu, tipc_sk_callback);

  	sock->sk = NULL;

  	return 0;

  }
  
  /**

   * tipc_bind - associate or disassocate TIPC name(s) with a socket

   * @sock: socket structure
   * @uaddr: socket address describing name(s) and desired operation
   * @uaddr_len: size of socket address data structure

   *

   * Name and name sequence binding is indicated using a positive scope value;
   * a negative scope value unbinds the specified name.  Specifying no name
   * (i.e. a socket address length of 0) unbinds all names from the socket.

   *

   * Returns 0 on success, errno otherwise

   *
   * NOTE: This routine doesn't need to take the socket lock since it doesn't
   *       access any non-constant socket information.

   */

  static int tipc_bind(struct socket *sock, struct sockaddr *uaddr,
  		     int uaddr_len)

  {

  	struct sock *sk = sock->sk;

  	struct sockaddr_tipc *addr = (struct sockaddr_tipc *)uaddr;

  	struct tipc_sock *tsk = tipc_sk(sk);

  	int res = -EINVAL;

  	lock_sock(sk);
  	if (unlikely(!uaddr_len)) {

  		res = tipc_sk_withdraw(tsk, 0, NULL);

  		goto exit;
  	}

  	if (uaddr_len < sizeof(struct sockaddr_tipc)) {
  		res = -EINVAL;
  		goto exit;
  	}
  	if (addr->family != AF_TIPC) {
  		res = -EAFNOSUPPORT;
  		goto exit;
  	}

  	if (addr->addrtype == TIPC_ADDR_NAME)
  		addr->addr.nameseq.upper = addr->addr.nameseq.lower;

  	else if (addr->addrtype != TIPC_ADDR_NAMESEQ) {
  		res = -EAFNOSUPPORT;
  		goto exit;
  	}

  	if ((addr->addr.nameseq.type < TIPC_RESERVED_TYPES) &&

  	    (addr->addr.nameseq.type != TIPC_TOP_SRV) &&

  	    (addr->addr.nameseq.type != TIPC_CFG_SRV)) {
  		res = -EACCES;
  		goto exit;
  	}

  	res = (addr->scope > 0) ?

  		tipc_sk_publish(tsk, addr->scope, &addr->addr.nameseq) :
  		tipc_sk_withdraw(tsk, -addr->scope, &addr->addr.nameseq);

  exit:
  	release_sock(sk);
  	return res;

  }

  /**

   * tipc_getname - get port ID of socket or peer socket

   * @sock: socket structure
   * @uaddr: area for returned socket address
   * @uaddr_len: area for returned length of socket address

   * @peer: 0 = own ID, 1 = current peer ID, 2 = current/former peer ID

   *

   * Returns 0 on success, errno otherwise

   *

   * NOTE: This routine doesn't need to take the socket lock since it only
   *       accesses socket information that is unchanging (or which changes in

   *       a completely predictable manner).

   */

  static int tipc_getname(struct socket *sock, struct sockaddr *uaddr,
  			int *uaddr_len, int peer)

  {

  	struct sockaddr_tipc *addr = (struct sockaddr_tipc *)uaddr;

  	struct sock *sk = sock->sk;
  	struct tipc_sock *tsk = tipc_sk(sk);

  	struct tipc_net *tn = net_generic(sock_net(sock->sk), tipc_net_id);

  	memset(addr, 0, sizeof(*addr));

  	if (peer) {

  		if ((!tipc_sk_connected(sk)) &&

  		    ((peer != 2) || (sk->sk_state != TIPC_DISCONNECTING)))

  			return -ENOTCONN;

  		addr->addr.id.ref = tsk_peer_port(tsk);
  		addr->addr.id.node = tsk_peer_node(tsk);

  	} else {

  		addr->addr.id.ref = tsk->portid;

  		addr->addr.id.node = tn->own_addr;

  	}

  
  	*uaddr_len = sizeof(*addr);
  	addr->addrtype = TIPC_ADDR_ID;
  	addr->family = AF_TIPC;
  	addr->scope = 0;

  	addr->addr.name.domain = 0;

  	return 0;

  }
  
  /**

   * tipc_poll - read and possibly block on pollmask

   * @file: file structure associated with the socket
   * @sock: socket for which to calculate the poll bits
   * @wait: ???
   *

   * Returns pollmask value
   *
   * COMMENTARY:
   * It appears that the usual socket locking mechanisms are not useful here
   * since the pollmask info is potentially out-of-date the moment this routine
   * exits.  TCP and other protocols seem to rely on higher level poll routines
   * to handle any preventable race conditions, so TIPC will do the same ...
   *

   * IMPORTANT: The fact that a read or write operation is indicated does NOT
   * imply that the operation will succeed, merely that it should be performed
   * and will not block.

   */

  static unsigned int tipc_poll(struct file *file, struct socket *sock,
  			      poll_table *wait)

  {

  	struct sock *sk = sock->sk;

  	struct tipc_sock *tsk = tipc_sk(sk);

  	u32 mask = 0;

  	sock_poll_wait(file, sk_sleep(sk), wait);

  	if (sk->sk_shutdown & RCV_SHUTDOWN)
  		mask |= POLLRDHUP | POLLIN | POLLRDNORM;
  	if (sk->sk_shutdown == SHUTDOWN_MASK)
  		mask |= POLLHUP;

  	switch (sk->sk_state) {
  	case TIPC_ESTABLISHED:

  	case TIPC_CONNECTING:

  		if (!tsk->cong_link_cnt && !tsk_conn_cong(tsk))

  			mask |= POLLOUT;

  		/* fall thru' */
  	case TIPC_LISTEN:

  		if (!skb_queue_empty(&sk->sk_receive_queue))
  			mask |= (POLLIN | POLLRDNORM);

  		break;
  	case TIPC_OPEN:

  		if (!tsk->cong_link_cnt)

  			mask |= POLLOUT;
  		if (tipc_sk_type_connectionless(sk) &&
  		    (!skb_queue_empty(&sk->sk_receive_queue)))
  			mask |= (POLLIN | POLLRDNORM);
  		break;
  	case TIPC_DISCONNECTING:
  		mask = (POLLIN | POLLRDNORM | POLLHUP);
  		break;

  	}

  
  	return mask;

  }

  /**
   * tipc_sendmcast - send multicast message
   * @sock: socket structure
   * @seq: destination address

   * @msg: message to send

   * @dlen: length of data to send
   * @timeout: timeout to wait for wakeup

   *
   * Called from function tipc_sendmsg(), which has done all sanity checks
   * Returns the number of bytes sent on success, or errno
   */
  static int tipc_sendmcast(struct  socket *sock, struct tipc_name_seq *seq,

  			  struct msghdr *msg, size_t dlen, long timeout)

  {
  	struct sock *sk = sock->sk;

  	struct tipc_sock *tsk = tipc_sk(sk);

  	struct tipc_msg *hdr = &tsk->phdr;

  	struct net *net = sock_net(sk);

  	int mtu = tipc_bcast_get_mtu(net);

  	struct tipc_mc_method *method = &tsk->mc_method;

  	u32 domain = addr_domain(net, TIPC_CLUSTER_SCOPE);

  	struct sk_buff_head pkts;

  	struct tipc_nlist dsts;

  	int rc;

  	/* Block or return if any destination link is congested */

  	rc = tipc_wait_for_cond(sock, &timeout, !tsk->cong_link_cnt);
  	if (unlikely(rc))
  		return rc;

  	/* Lookup destination nodes */
  	tipc_nlist_init(&dsts, tipc_own_addr(net));
  	tipc_nametbl_lookup_dst_nodes(net, seq->type, seq->lower,
  				      seq->upper, domain, &dsts);
  	if (!dsts.local && !dsts.remote)
  		return -EHOSTUNREACH;
  
  	/* Build message header */

  	msg_set_type(hdr, TIPC_MCAST_MSG);

  	msg_set_hdr_sz(hdr, MCAST_H_SIZE);

  	msg_set_lookup_scope(hdr, TIPC_CLUSTER_SCOPE);
  	msg_set_destport(hdr, 0);
  	msg_set_destnode(hdr, 0);
  	msg_set_nametype(hdr, seq->type);
  	msg_set_namelower(hdr, seq->lower);
  	msg_set_nameupper(hdr, seq->upper);

  	/* Build message as chain of buffers */

  	skb_queue_head_init(&pkts);
  	rc = tipc_msg_build(hdr, msg, 0, dlen, mtu, &pkts);

  	/* Send message if build was successful */
  	if (unlikely(rc == dlen))

  		rc = tipc_mcast_xmit(net, &pkts, method, &dsts,

  				     &tsk->cong_link_cnt);
  
  	tipc_nlist_purge(&dsts);

  
  	return rc ? rc : dlen;

  }

  /**
   * tipc_sk_mcast_rcv - Deliver multicast messages to all destination sockets
   * @arrvq: queue with arriving messages, to be cloned after destination lookup
   * @inputq: queue with cloned messages, delivered to socket after dest lookup
   *
   * Multi-threaded: parallel calls with reference to same queues may occur

   */

  void tipc_sk_mcast_rcv(struct net *net, struct sk_buff_head *arrvq,
  		       struct sk_buff_head *inputq)

  {

  	struct tipc_msg *msg;

  	struct list_head dports;

  	u32 portid;

  	u32 scope = TIPC_CLUSTER_SCOPE;

  	struct sk_buff_head tmpq;
  	uint hsz;
  	struct sk_buff *skb, *_skb;

  	__skb_queue_head_init(&tmpq);

  	INIT_LIST_HEAD(&dports);

  	skb = tipc_skb_peek(arrvq, &inputq->lock);
  	for (; skb; skb = tipc_skb_peek(arrvq, &inputq->lock)) {
  		msg = buf_msg(skb);
  		hsz = skb_headroom(skb) + msg_hdr_sz(msg);
  
  		if (in_own_node(net, msg_orignode(msg)))
  			scope = TIPC_NODE_SCOPE;
  
  		/* Create destination port list and message clones: */
  		tipc_nametbl_mc_translate(net,
  					  msg_nametype(msg), msg_namelower(msg),
  					  msg_nameupper(msg), scope, &dports);

  		portid = u32_pop(&dports);
  		for (; portid; portid = u32_pop(&dports)) {

  			_skb = __pskb_copy(skb, hsz, GFP_ATOMIC);
  			if (_skb) {
  				msg_set_destport(buf_msg(_skb), portid);
  				__skb_queue_tail(&tmpq, _skb);
  				continue;
  			}
  			pr_warn("Failed to clone mcast rcv buffer
  ");

  		}

  		/* Append to inputq if not already done by other thread */
  		spin_lock_bh(&inputq->lock);
  		if (skb_peek(arrvq) == skb) {
  			skb_queue_splice_tail_init(&tmpq, inputq);
  			kfree_skb(__skb_dequeue(arrvq));
  		}
  		spin_unlock_bh(&inputq->lock);
  		__skb_queue_purge(&tmpq);
  		kfree_skb(skb);

  	}

  	tipc_sk_rcv(net, inputq);

  }

  /**

   * tipc_sk_proto_rcv - receive a connection mng protocol message
   * @tsk: receiving socket

   * @skb: pointer to message buffer.

   */

  static void tipc_sk_proto_rcv(struct tipc_sock *tsk, struct sk_buff *skb,
  			      struct sk_buff_head *xmitq)

  {

  	struct sock *sk = &tsk->sk;

  	u32 onode = tsk_own_node(tsk);

  	struct tipc_msg *hdr = buf_msg(skb);
  	int mtyp = msg_type(hdr);

  	bool conn_cong;

  	/* Ignore if connection cannot be validated: */

  	if (!tsk_peer_msg(tsk, hdr))

  		goto exit;

  	if (unlikely(msg_errcode(hdr))) {
  		tipc_set_sk_state(sk, TIPC_DISCONNECTING);
  		tipc_node_remove_conn(sock_net(sk), tsk_peer_node(tsk),
  				      tsk_peer_port(tsk));
  		sk->sk_state_change(sk);
  		goto exit;
  	}

  	tsk->probe_unacked = false;

  	if (mtyp == CONN_PROBE) {
  		msg_set_type(hdr, CONN_PROBE_REPLY);

  		if (tipc_msg_reverse(onode, &skb, TIPC_OK))
  			__skb_queue_tail(xmitq, skb);

  		return;
  	} else if (mtyp == CONN_ACK) {

  		conn_cong = tsk_conn_cong(tsk);

  		tsk->snt_unacked -= msg_conn_ack(hdr);
  		if (tsk->peer_caps & TIPC_BLOCK_FLOWCTL)
  			tsk->snd_win = msg_adv_win(hdr);

  		if (conn_cong)

  			sk->sk_write_space(sk);
  	} else if (mtyp != CONN_PROBE_REPLY) {
  		pr_warn("Received unknown CONN_PROTO msg
  ");

  	}

  exit:

  	kfree_skb(skb);

  }

  /**

   * tipc_sendmsg - send message in connectionless manner

   * @sock: socket structure
   * @m: message to send

   * @dsz: amount of user data to be sent

   *

   * Message must have an destination specified explicitly.

   * Used for SOCK_RDM and SOCK_DGRAM messages,

   * and for 'SYN' messages on SOCK_SEQPACKET and SOCK_STREAM connections.
   * (Note: 'SYN+' is prohibited on SOCK_STREAM.)

   *

   * Returns the number of bytes sent on success, or errno otherwise
   */

  static int tipc_sendmsg(struct socket *sock,

  			struct msghdr *m, size_t dsz)

  {

  	struct sock *sk = sock->sk;
  	int ret;
  
  	lock_sock(sk);
  	ret = __tipc_sendmsg(sock, m, dsz);
  	release_sock(sk);
  
  	return ret;
  }

  static int __tipc_sendmsg(struct socket *sock, struct msghdr *m, size_t dlen)

  {

  	struct sock *sk = sock->sk;

  	struct net *net = sock_net(sk);

  	struct tipc_sock *tsk = tipc_sk(sk);
  	DECLARE_SOCKADDR(struct sockaddr_tipc *, dest, m->msg_name);
  	long timeout = sock_sndtimeo(sk, m->msg_flags & MSG_DONTWAIT);
  	struct list_head *clinks = &tsk->cong_links;
  	bool syn = !tipc_sk_type_connectionless(sk);
  	struct tipc_msg *hdr = &tsk->phdr;

  	struct tipc_name_seq *seq;

  	struct sk_buff_head pkts;
  	u32 type, inst, domain;
  	u32 dnode, dport;
  	int mtu, rc;

  	if (unlikely(dlen > TIPC_MAX_USER_MSG_SIZE))

  		return -EMSGSIZE;

  	if (unlikely(!dest)) {

  		dest = &tsk->peer;
  		if (!syn || dest->family != AF_TIPC)

  			return -EDESTADDRREQ;

  	}

  
  	if (unlikely(m->msg_namelen < sizeof(*dest)))
  		return -EINVAL;
  
  	if (unlikely(dest->family != AF_TIPC))
  		return -EINVAL;
  
  	if (unlikely(syn)) {

  		if (sk->sk_state == TIPC_LISTEN)

  			return -EPIPE;

  		if (sk->sk_state != TIPC_OPEN)

  			return -EISCONN;
  		if (tsk->published)
  			return -EOPNOTSUPP;

  		if (dest->addrtype == TIPC_ADDR_NAME) {

  			tsk->conn_type = dest->addr.name.name.type;
  			tsk->conn_instance = dest->addr.name.name.instance;

  		}

  	}

  	seq = &dest->addr.nameseq;
  	if (dest->addrtype == TIPC_ADDR_MCAST)
  		return tipc_sendmcast(sock, seq, m, dlen, timeout);

  	if (dest->addrtype == TIPC_ADDR_NAME) {
  		type = dest->addr.name.name.type;
  		inst = dest->addr.name.name.instance;
  		domain = dest->addr.name.domain;

  		dnode = domain;

  		msg_set_type(hdr, TIPC_NAMED_MSG);
  		msg_set_hdr_sz(hdr, NAMED_H_SIZE);
  		msg_set_nametype(hdr, type);
  		msg_set_nameinst(hdr, inst);
  		msg_set_lookup_scope(hdr, tipc_addr_scope(domain));

  		dport = tipc_nametbl_translate(net, type, inst, &dnode);

  		msg_set_destnode(hdr, dnode);
  		msg_set_destport(hdr, dport);

  		if (unlikely(!dport && !dnode))
  			return -EHOSTUNREACH;

  	} else if (dest->addrtype == TIPC_ADDR_ID) {
  		dnode = dest->addr.id.node;

  		msg_set_type(hdr, TIPC_DIRECT_MSG);
  		msg_set_lookup_scope(hdr, 0);
  		msg_set_destnode(hdr, dnode);
  		msg_set_destport(hdr, dest->addr.id.ref);
  		msg_set_hdr_sz(hdr, BASIC_H_SIZE);

  	}

  	/* Block or return if destination link is congested */
  	rc = tipc_wait_for_cond(sock, &timeout, !u32_find(clinks, dnode));
  	if (unlikely(rc))
  		return rc;
  
  	skb_queue_head_init(&pkts);

  	mtu = tipc_node_get_mtu(net, dnode, tsk->portid);

  	rc = tipc_msg_build(hdr, m, 0, dlen, mtu, &pkts);
  	if (unlikely(rc != dlen))

  		return rc;

  	rc = tipc_node_xmit(net, &pkts, dnode, tsk->portid);
  	if (unlikely(rc == -ELINKCONG)) {
  		u32_push(clinks, dnode);
  		tsk->cong_link_cnt++;
  		rc = 0;
  	}

  	if (unlikely(syn && !rc))
  		tipc_set_sk_state(sk, TIPC_CONNECTING);
  
  	return rc ? rc : dlen;

  }

  /**

   * tipc_sendstream - send stream-oriented data

   * @sock: socket structure

   * @m: data to send
   * @dsz: total length of data to be transmitted

   *

   * Used for SOCK_STREAM data.

   *

   * Returns the number of bytes sent on success (or partial success),
   * or errno if no data sent

   */

  static int tipc_sendstream(struct socket *sock, struct msghdr *m, size_t dsz)

  {

  	struct sock *sk = sock->sk;

  	int ret;
  
  	lock_sock(sk);

  	ret = __tipc_sendstream(sock, m, dsz);

  	release_sock(sk);
  
  	return ret;
  }

  static int __tipc_sendstream(struct socket *sock, struct msghdr *m, size_t dlen)

  {
  	struct sock *sk = sock->sk;

  	DECLARE_SOCKADDR(struct sockaddr_tipc *, dest, m->msg_name);

  	long timeout = sock_sndtimeo(sk, m->msg_flags & MSG_DONTWAIT);
  	struct tipc_sock *tsk = tipc_sk(sk);
  	struct tipc_msg *hdr = &tsk->phdr;
  	struct net *net = sock_net(sk);
  	struct sk_buff_head pkts;
  	u32 dnode = tsk_peer_node(tsk);
  	int send, sent = 0;
  	int rc = 0;

  	skb_queue_head_init(&pkts);

  	if (unlikely(dlen > INT_MAX))
  		return -EMSGSIZE;

  	/* Handle implicit connection setup */
  	if (unlikely(dest)) {
  		rc = __tipc_sendmsg(sock, m, dlen);

  		if (dlen && dlen == rc) {
  			tsk->peer_caps = tipc_node_get_capabilities(net, dnode);

  			tsk->snt_unacked = tsk_inc(tsk, dlen + msg_hdr_sz(hdr));

  		}

  		return rc;

  	}

  	do {

  		rc = tipc_wait_for_cond(sock, &timeout,
  					(!tsk->cong_link_cnt &&

  					 !tsk_conn_cong(tsk) &&
  					 tipc_sk_connected(sk)));

  		if (unlikely(rc))
  			break;
  
  		send = min_t(size_t, dlen - sent, TIPC_MAX_USER_MSG_SIZE);
  		rc = tipc_msg_build(hdr, m, sent, send, tsk->max_pkt, &pkts);
  		if (unlikely(rc != send))
  			break;
  
  		rc = tipc_node_xmit(net, &pkts, dnode, tsk->portid);
  		if (unlikely(rc == -ELINKCONG)) {
  			tsk->cong_link_cnt = 1;
  			rc = 0;
  		}
  		if (likely(!rc)) {
  			tsk->snt_unacked += tsk_inc(tsk, send + MIN_H_SIZE);
  			sent += send;
  		}
  	} while (sent < dlen && !rc);

  	return sent ? sent : rc;

  }

  /**

   * tipc_send_packet - send a connection-oriented message

   * @sock: socket structure

   * @m: message to send
   * @dsz: length of data to be transmitted

   *

   * Used for SOCK_SEQPACKET messages.

   *

   * Returns the number of bytes sent on success, or errno otherwise

   */

  static int tipc_send_packet(struct socket *sock, struct msghdr *m, size_t dsz)

  {

  	if (dsz > TIPC_MAX_USER_MSG_SIZE)
  		return -EMSGSIZE;

  	return tipc_sendstream(sock, m, dsz);

  }

  /* tipc_sk_finish_conn - complete the setup of a connection

   */

  static void tipc_sk_finish_conn(struct tipc_sock *tsk, u32 peer_port,

  				u32 peer_node)

  {

  	struct sock *sk = &tsk->sk;
  	struct net *net = sock_net(sk);

  	struct tipc_msg *msg = &tsk->phdr;

  	msg_set_destnode(msg, peer_node);
  	msg_set_destport(msg, peer_port);
  	msg_set_type(msg, TIPC_CONN_MSG);
  	msg_set_lookup_scope(msg, 0);
  	msg_set_hdr_sz(msg, SHORT_H_SIZE);

  	sk_reset_timer(sk, &sk->sk_timer, jiffies + CONN_PROBING_INTERVAL);

  	tipc_set_sk_state(sk, TIPC_ESTABLISHED);

  	tipc_node_add_conn(net, peer_node, tsk->portid, peer_port);
  	tsk->max_pkt = tipc_node_get_mtu(net, peer_node, tsk->portid);

  	tsk->peer_caps = tipc_node_get_capabilities(net, peer_node);

  	if (tsk->peer_caps & TIPC_BLOCK_FLOWCTL)
  		return;
  
  	/* Fall back to message based flow control */
  	tsk->rcv_win = FLOWCTL_MSG_WIN;
  	tsk->snd_win = FLOWCTL_MSG_WIN;

  }
  
  /**
   * set_orig_addr - capture sender's address for received message
   * @m: descriptor for message info
   * @msg: received message header

   *

   * Note: Address is not captured if not requested by receiver.
   */

  static void set_orig_addr(struct msghdr *m, struct tipc_msg *msg)

  {

  	DECLARE_SOCKADDR(struct sockaddr_tipc *, addr, m->msg_name);

  	if (addr) {

  		addr->family = AF_TIPC;
  		addr->addrtype = TIPC_ADDR_ID;

  		memset(&addr->addr, 0, sizeof(addr->addr));

  		addr->addr.id.ref = msg_origport(msg);
  		addr->addr.id.node = msg_orignode(msg);

  		addr->addr.name.domain = 0;	/* could leave uninitialized */
  		addr->scope = 0;		/* could leave uninitialized */

  		m->msg_namelen = sizeof(struct sockaddr_tipc);
  	}
  }
  
  /**

   * tipc_sk_anc_data_recv - optionally capture ancillary data for received message

   * @m: descriptor for message info
   * @msg: received message header

   * @tsk: TIPC port associated with message

   *

   * Note: Ancillary data is not captured if not requested by receiver.

   *

   * Returns 0 if successful, otherwise errno
   */

  static int tipc_sk_anc_data_recv(struct msghdr *m, struct tipc_msg *msg,
  				 struct tipc_sock *tsk)

  {
  	u32 anc_data[3];
  	u32 err;
  	u32 dest_type;

  	int has_name;

  	int res;
  
  	if (likely(m->msg_controllen == 0))
  		return 0;
  
  	/* Optionally capture errored message object(s) */

  	err = msg ? msg_errcode(msg) : 0;
  	if (unlikely(err)) {
  		anc_data[0] = err;
  		anc_data[1] = msg_data_sz(msg);

  		res = put_cmsg(m, SOL_TIPC, TIPC_ERRINFO, 8, anc_data);
  		if (res)

  			return res;

  		if (anc_data[1]) {
  			res = put_cmsg(m, SOL_TIPC, TIPC_RETDATA, anc_data[1],
  				       msg_data(msg));
  			if (res)
  				return res;
  		}

  	}
  
  	/* Optionally capture message destination object */

  	dest_type = msg ? msg_type(msg) : TIPC_DIRECT_MSG;
  	switch (dest_type) {
  	case TIPC_NAMED_MSG:

  		has_name = 1;

  		anc_data[0] = msg_nametype(msg);
  		anc_data[1] = msg_namelower(msg);
  		anc_data[2] = msg_namelower(msg);
  		break;
  	case TIPC_MCAST_MSG:

  		has_name = 1;

  		anc_data[0] = msg_nametype(msg);
  		anc_data[1] = msg_namelower(msg);
  		anc_data[2] = msg_nameupper(msg);
  		break;
  	case TIPC_CONN_MSG:

  		has_name = (tsk->conn_type != 0);
  		anc_data[0] = tsk->conn_type;
  		anc_data[1] = tsk->conn_instance;
  		anc_data[2] = tsk->conn_instance;

  		break;
  	default:

  		has_name = 0;

  	}

  	if (has_name) {
  		res = put_cmsg(m, SOL_TIPC, TIPC_DESTNAME, 12, anc_data);
  		if (res)
  			return res;
  	}

  
  	return 0;
  }

  static void tipc_sk_send_ack(struct tipc_sock *tsk)

  {

  	struct sock *sk = &tsk->sk;
  	struct net *net = sock_net(sk);

  	struct sk_buff *skb = NULL;

  	struct tipc_msg *msg;

  	u32 peer_port = tsk_peer_port(tsk);
  	u32 dnode = tsk_peer_node(tsk);

  	if (!tipc_sk_connected(sk))

  		return;

  	skb = tipc_msg_create(CONN_MANAGER, CONN_ACK, INT_H_SIZE, 0,
  			      dnode, tsk_own_node(tsk), peer_port,
  			      tsk->portid, TIPC_OK);

  	if (!skb)

  		return;

  	msg = buf_msg(skb);

  	msg_set_conn_ack(msg, tsk->rcv_unacked);
  	tsk->rcv_unacked = 0;
  
  	/* Adjust to and advertize the correct window limit */
  	if (tsk->peer_caps & TIPC_BLOCK_FLOWCTL) {
  		tsk->rcv_win = tsk_adv_blocks(tsk->sk.sk_rcvbuf);
  		msg_set_adv_win(msg, tsk->rcv_win);
  	}

  	tipc_node_xmit_skb(net, skb, dnode, msg_link_selector(msg));

  }

  static int tipc_wait_for_rcvmsg(struct socket *sock, long *timeop)

  {
  	struct sock *sk = sock->sk;
  	DEFINE_WAIT(wait);

  	long timeo = *timeop;

  	int err = sock_error(sk);
  
  	if (err)
  		return err;

  
  	for (;;) {
  		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);

  		if (timeo && skb_queue_empty(&sk->sk_receive_queue)) {

  			if (sk->sk_shutdown & RCV_SHUTDOWN) {

  				err = -ENOTCONN;
  				break;
  			}
  			release_sock(sk);
  			timeo = schedule_timeout(timeo);
  			lock_sock(sk);
  		}
  		err = 0;
  		if (!skb_queue_empty(&sk->sk_receive_queue))
  			break;

  		err = -EAGAIN;
  		if (!timeo)
  			break;

  		err = sock_intr_errno(timeo);
  		if (signal_pending(current))
  			break;

  
  		err = sock_error(sk);
  		if (err)
  			break;

  	}
  	finish_wait(sk_sleep(sk), &wait);

  	*timeop = timeo;

  	return err;
  }

  /**

   * tipc_recvmsg - receive packet-oriented message

   * @m: descriptor for message info

   * @buflen: length of user buffer area

   * @flags: receive flags