text: /*
   * net/tipc/port.c: TIPC port code
   *
   * Copyright (c) 1992-2007, 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 "core.h"
  #include "config.h"
  #include "port.h"
  #include "name_table.h"
  
  /* Connection management: */
  #define PROBING_INTERVAL 3600000	/* [ms] => 1 h */
  #define CONFIRMED 0
  #define PROBING 1
  
  #define MAX_REJECT_SIZE 1024
  
  DEFINE_SPINLOCK(tipc_port_list_lock);
  
  static LIST_HEAD(ports);
  static void port_handle_node_down(unsigned long ref);
  static struct sk_buff *port_build_self_abort_msg(struct tipc_port *, u32 err);
  static struct sk_buff *port_build_peer_abort_msg(struct tipc_port *, u32 err);
  static void port_timeout(unsigned long ref);
  
  
  static u32 port_peernode(struct tipc_port *p_ptr)
  {
  	return msg_destnode(&p_ptr->phdr);
  }
  
  static u32 port_peerport(struct tipc_port *p_ptr)
  {
  	return msg_destport(&p_ptr->phdr);
  }
  
  /**
   * tipc_port_peer_msg - verify 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.
   */
  int tipc_port_peer_msg(struct tipc_port *p_ptr, struct tipc_msg *msg)
  {
  	u32 peernode;
  	u32 orignode;
  
  	if (msg_origport(msg) != port_peerport(p_ptr))
  		return 0;
  
  	orignode = msg_orignode(msg);
  	peernode = port_peernode(p_ptr);
  	return (orignode == peernode) ||
  		(!orignode && (peernode == tipc_own_addr)) ||
  		(!peernode && (orignode == tipc_own_addr));
  }
  
  /**
   * tipc_multicast - send a multicast message to local and remote destinations
   */
  int tipc_multicast(u32 ref, struct tipc_name_seq const *seq,
  		   struct iovec const *msg_sect, unsigned int len)
  {
  	struct tipc_msg *hdr;
  	struct sk_buff *buf;
  	struct sk_buff *ibuf = NULL;
  	struct tipc_port_list dports = {0, NULL, };
  	struct tipc_port *oport = tipc_port_deref(ref);
  	int ext_targets;
  	int res;
  
  	if (unlikely(!oport))
  		return -EINVAL;
  
  	/* Create multicast message */
  	hdr = &oport->phdr;
  	msg_set_type(hdr, TIPC_MCAST_MSG);
  	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);
  	msg_set_hdr_sz(hdr, MCAST_H_SIZE);
  	res = tipc_msg_build(hdr, msg_sect, len, MAX_MSG_SIZE, &buf);
  	if (unlikely(!buf))
  		return res;
  
  	/* Figure out where to send multicast message */
  	ext_targets = tipc_nametbl_mc_translate(seq->type, seq->lower, seq->upper,
  						TIPC_NODE_SCOPE, &dports);
  
  	/* Send message to destinations (duplicate it only if necessary) */
  	if (ext_targets) {
  		if (dports.count != 0) {
  			ibuf = skb_copy(buf, GFP_ATOMIC);
  			if (ibuf == NULL) {
  				tipc_port_list_free(&dports);
  				kfree_skb(buf);
  				return -ENOMEM;
  			}
  		}
  		res = tipc_bclink_send_msg(buf);
  		if ((res < 0) && (dports.count != 0))
  			kfree_skb(ibuf);
  	} else {
  		ibuf = buf;
  	}
  
  	if (res >= 0) {
  		if (ibuf)
  			tipc_port_recv_mcast(ibuf, &dports);
  	} else {
  		tipc_port_list_free(&dports);
  	}
  	return res;
  }
  
  /**
   * tipc_port_recv_mcast - deliver multicast message to all destination ports
   *
   * If there is no port list, perform a lookup to create one
   */
  void tipc_port_recv_mcast(struct sk_buff *buf, struct tipc_port_list *dp)
  {
  	struct tipc_msg *msg;
  	struct tipc_port_list dports = {0, NULL, };
  	struct tipc_port_list *item = dp;
  	int cnt = 0;
  
  	msg = buf_msg(buf);
  
  	/* Create destination port list, if one wasn't supplied */
  	if (dp == NULL) {
  		tipc_nametbl_mc_translate(msg_nametype(msg),
  				     msg_namelower(msg),
  				     msg_nameupper(msg),
  				     TIPC_CLUSTER_SCOPE,
  				     &dports);
  		item = dp = &dports;
  	}
  
  	/* Deliver a copy of message to each destination port */
  	if (dp->count != 0) {
  		msg_set_destnode(msg, tipc_own_addr);
  		if (dp->count == 1) {
  			msg_set_destport(msg, dp->ports[0]);
  			tipc_port_recv_msg(buf);
  			tipc_port_list_free(dp);
  			return;
  		}
  		for (; cnt < dp->count; cnt++) {
  			int index = cnt % PLSIZE;
  			struct sk_buff *b = skb_clone(buf, GFP_ATOMIC);
  
  			if (b == NULL) {
  				pr_warn("Unable to deliver multicast message(s)\n");
  				goto exit;
  			}
  			if ((index == 0) && (cnt != 0))
  				item = item->next;
  			msg_set_destport(buf_msg(b), item->ports[index]);
  			tipc_port_recv_msg(b);
  		}
  	}
  exit:
  	kfree_skb(buf);
  	tipc_port_list_free(dp);
  }
  
  /**
   * tipc_createport - create a generic TIPC port
   *
   * Returns pointer to (locked) TIPC port, or NULL if unable to create it
   */
  struct tipc_port *tipc_createport(struct sock *sk,
  				  u32 (*dispatcher)(struct tipc_port *,
  				  struct sk_buff *),
  				  void (*wakeup)(struct tipc_port *),
  				  const u32 importance)
  {
  	struct tipc_port *p_ptr;
  	struct tipc_msg *msg;
  	u32 ref;
  
  	p_ptr = kzalloc(sizeof(*p_ptr), GFP_ATOMIC);
  	if (!p_ptr) {
  		pr_warn("Port creation failed, no memory\n");
  		return NULL;
  	}
  	ref = tipc_ref_acquire(p_ptr, &p_ptr->lock);
  	if (!ref) {
  		pr_warn("Port creation failed, ref. table exhausted\n");
  		kfree(p_ptr);
  		return NULL;
  	}
  
  	p_ptr->sk = sk;
  	p_ptr->max_pkt = MAX_PKT_DEFAULT;
  	p_ptr->ref = ref;
  	INIT_LIST_HEAD(&p_ptr->wait_list);
  	INIT_LIST_HEAD(&p_ptr->subscription.nodesub_list);
  	p_ptr->dispatcher = dispatcher;
  	p_ptr->wakeup = wakeup;
  	k_init_timer(&p_ptr->timer, (Handler)port_timeout, ref);
  	INIT_LIST_HEAD(&p_ptr->publications);
  	INIT_LIST_HEAD(&p_ptr->port_list);
  
  	/*
  	 * Must hold port list lock while initializing message header template
  	 * to ensure a change to node's own network address doesn't result
  	 * in template containing out-dated network address information
  	 */
  	spin_lock_bh(&tipc_port_list_lock);
  	msg = &p_ptr->phdr;
  	tipc_msg_init(msg, importance, TIPC_NAMED_MSG, NAMED_H_SIZE, 0);
  	msg_set_origport(msg, ref);
  	list_add_tail(&p_ptr->port_list, &ports);
  	spin_unlock_bh(&tipc_port_list_lock);
  	return p_ptr;
  }
  
  int tipc_deleteport(struct tipc_port *p_ptr)
  {
  	struct sk_buff *buf = NULL;
  
  	tipc_withdraw(p_ptr, 0, NULL);
  
  	spin_lock_bh(p_ptr->lock);
  	tipc_ref_discard(p_ptr->ref);
  	spin_unlock_bh(p_ptr->lock);
  
  	k_cancel_timer(&p_ptr->timer);
  	if (p_ptr->connected) {
  		buf = port_build_peer_abort_msg(p_ptr, TIPC_ERR_NO_PORT);
  		tipc_nodesub_unsubscribe(&p_ptr->subscription);
  	}
  
  	spin_lock_bh(&tipc_port_list_lock);
  	list_del(&p_ptr->port_list);
  	list_del(&p_ptr->wait_list);
  	spin_unlock_bh(&tipc_port_list_lock);
  	k_term_timer(&p_ptr->timer);
  	kfree(p_ptr);
  	tipc_net_route_msg(buf);
  	return 0;
  }
  
  static int port_unreliable(struct tipc_port *p_ptr)
  {
  	return msg_src_droppable(&p_ptr->phdr);
  }
  
  int tipc_portunreliable(u32 ref, unsigned int *isunreliable)
  {
  	struct tipc_port *p_ptr;
  
  	p_ptr = tipc_port_lock(ref);
  	if (!p_ptr)
  		return -EINVAL;
  	*isunreliable = port_unreliable(p_ptr);
  	tipc_port_unlock(p_ptr);
  	return 0;
  }
  
  int tipc_set_portunreliable(u32 ref, unsigned int isunreliable)
  {
  	struct tipc_port *p_ptr;
  
  	p_ptr = tipc_port_lock(ref);
  	if (!p_ptr)
  		return -EINVAL;
  	msg_set_src_droppable(&p_ptr->phdr, (isunreliable != 0));
  	tipc_port_unlock(p_ptr);
  	return 0;
  }
  
  static int port_unreturnable(struct tipc_port *p_ptr)
  {
  	return msg_dest_droppable(&p_ptr->phdr);
  }
  
  int tipc_portunreturnable(u32 ref, unsigned int *isunrejectable)
  {
  	struct tipc_port *p_ptr;
  
  	p_ptr = tipc_port_lock(ref);
  	if (!p_ptr)
  		return -EINVAL;
  	*isunrejectable = port_unreturnable(p_ptr);
  	tipc_port_unlock(p_ptr);
  	return 0;
  }
  
  int tipc_set_portunreturnable(u32 ref, unsigned int isunrejectable)
  {
  	struct tipc_port *p_ptr;
  
  	p_ptr = tipc_port_lock(ref);
  	if (!p_ptr)
  		return -EINVAL;
  	msg_set_dest_droppable(&p_ptr->phdr, (isunrejectable != 0));
  	tipc_port_unlock(p_ptr);
  	return 0;
  }
  
  /*
   * port_build_proto_msg(): create connection protocol message for port
   *
   * On entry the port must be locked and connected.
   */
  static struct sk_buff *port_build_proto_msg(struct tipc_port *p_ptr,
  					    u32 type, u32 ack)
  {
  	struct sk_buff *buf;
  	struct tipc_msg *msg;
  
  	buf = tipc_buf_acquire(INT_H_SIZE);
  	if (buf) {
  		msg = buf_msg(buf);
  		tipc_msg_init(msg, CONN_MANAGER, type, INT_H_SIZE,
  			      port_peernode(p_ptr));
  		msg_set_destport(msg, port_peerport(p_ptr));
  		msg_set_origport(msg, p_ptr->ref);
  		msg_set_msgcnt(msg, ack);
  	}
  	return buf;
  }
  
  int tipc_reject_msg(struct sk_buff *buf, u32 err)
  {
  	struct tipc_msg *msg = buf_msg(buf);
  	struct sk_buff *rbuf;
  	struct tipc_msg *rmsg;
  	int hdr_sz;
  	u32 imp;
  	u32 data_sz = msg_data_sz(msg);
  	u32 src_node;
  	u32 rmsg_sz;
  
  	/* discard rejected message if it shouldn't be returned to sender */
  	if (WARN(!msg_isdata(msg),
  		 "attempt to reject message with user=%u", msg_user(msg))) {
  		dump_stack();
  		goto exit;
  	}
  	if (msg_errcode(msg) || msg_dest_droppable(msg))
  		goto exit;
  
  	/*
  	 * construct returned message by copying rejected message header and
  	 * data (or subset), then updating header fields that need adjusting
  	 */
  	hdr_sz = msg_hdr_sz(msg);
  	rmsg_sz = hdr_sz + min_t(u32, data_sz, MAX_REJECT_SIZE);
  
  	rbuf = tipc_buf_acquire(rmsg_sz);
  	if (rbuf == NULL)
  		goto exit;
  
  	rmsg = buf_msg(rbuf);
  	skb_copy_to_linear_data(rbuf, msg, rmsg_sz);
  
  	if (msg_connected(rmsg)) {
  		imp = msg_importance(rmsg);
  		if (imp < TIPC_CRITICAL_IMPORTANCE)
  			msg_set_importance(rmsg, ++imp);
  	}
  	msg_set_non_seq(rmsg, 0);
  	msg_set_size(rmsg, rmsg_sz);
  	msg_set_errcode(rmsg, err);
  	msg_set_prevnode(rmsg, tipc_own_addr);
  	msg_swap_words(rmsg, 4, 5);
  	if (!msg_short(rmsg))
  		msg_swap_words(rmsg, 6, 7);
  
  	/* send self-abort message when rejecting on a connected port */
  	if (msg_connected(msg)) {
  		struct tipc_port *p_ptr = tipc_port_lock(msg_destport(msg));
  
  		if (p_ptr) {
  			struct sk_buff *abuf = NULL;
  
  			if (p_ptr->connected)
  				abuf = port_build_self_abort_msg(p_ptr, err);
  			tipc_port_unlock(p_ptr);
  			tipc_net_route_msg(abuf);
  		}
  	}
  
  	/* send returned message & dispose of rejected message */
  	src_node = msg_prevnode(msg);
  	if (in_own_node(src_node))
  		tipc_port_recv_msg(rbuf);
  	else
  		tipc_link_send(rbuf, src_node, msg_link_selector(rmsg));
  exit:
  	kfree_skb(buf);
  	return data_sz;
  }
  
  int tipc_port_reject_sections(struct tipc_port *p_ptr, struct tipc_msg *hdr,
  			      struct iovec const *msg_sect, unsigned int len,
  			      int err)
  {
  	struct sk_buff *buf;
  	int res;
  
  	res = tipc_msg_build(hdr, msg_sect, len, MAX_MSG_SIZE, &buf);
  	if (!buf)
  		return res;
  
  	return tipc_reject_msg(buf, err);
  }
  
  static void port_timeout(unsigned long ref)
  {
  	struct tipc_port *p_ptr = tipc_port_lock(ref);
  	struct sk_buff *buf = NULL;
  
  	if (!p_ptr)
  		return;
  
  	if (!p_ptr->connected) {
  		tipc_port_unlock(p_ptr);
  		return;
  	}
  
  	/* Last probe answered ? */
  	if (p_ptr->probing_state == PROBING) {
  		buf = port_build_self_abort_msg(p_ptr, TIPC_ERR_NO_PORT);
  	} else {
  		buf = port_build_proto_msg(p_ptr, CONN_PROBE, 0);
  		p_ptr->probing_state = PROBING;
  		k_start_timer(&p_ptr->timer, p_ptr->probing_interval);
  	}
  	tipc_port_unlock(p_ptr);
  	tipc_net_route_msg(buf);
  }
  
  
  static void port_handle_node_down(unsigned long ref)
  {
  	struct tipc_port *p_ptr = tipc_port_lock(ref);
  	struct sk_buff *buf = NULL;
  
  	if (!p_ptr)
  		return;
  	buf = port_build_self_abort_msg(p_ptr, TIPC_ERR_NO_NODE);
  	tipc_port_unlock(p_ptr);
  	tipc_net_route_msg(buf);
  }
  
  
  static struct sk_buff *port_build_self_abort_msg(struct tipc_port *p_ptr, u32 err)
  {
  	struct sk_buff *buf = port_build_peer_abort_msg(p_ptr, err);
  
  	if (buf) {
  		struct tipc_msg *msg = buf_msg(buf);
  		msg_swap_words(msg, 4, 5);
  		msg_swap_words(msg, 6, 7);
  	}
  	return buf;
  }
  
  
  static struct sk_buff *port_build_peer_abort_msg(struct tipc_port *p_ptr, u32 err)
  {
  	struct sk_buff *buf;
  	struct tipc_msg *msg;
  	u32 imp;
  
  	if (!p_ptr->connected)
  		return NULL;
  
  	buf = tipc_buf_acquire(BASIC_H_SIZE);
  	if (buf) {
  		msg = buf_msg(buf);
  		memcpy(msg, &p_ptr->phdr, BASIC_H_SIZE);
  		msg_set_hdr_sz(msg, BASIC_H_SIZE);
  		msg_set_size(msg, BASIC_H_SIZE);
  		imp = msg_importance(msg);
  		if (imp < TIPC_CRITICAL_IMPORTANCE)
  			msg_set_importance(msg, ++imp);
  		msg_set_errcode(msg, err);
  	}
  	return buf;
  }
  
  void tipc_port_recv_proto_msg(struct sk_buff *buf)
  {
  	struct tipc_msg *msg = buf_msg(buf);
  	struct tipc_port *p_ptr;
  	struct sk_buff *r_buf = NULL;
  	u32 destport = msg_destport(msg);
  	int wakeable;
  
  	/* Validate connection */
  	p_ptr = tipc_port_lock(destport);
  	if (!p_ptr || !p_ptr->connected || !tipc_port_peer_msg(p_ptr, msg)) {
  		r_buf = tipc_buf_acquire(BASIC_H_SIZE);
  		if (r_buf) {
  			msg = buf_msg(r_buf);
  			tipc_msg_init(msg, TIPC_HIGH_IMPORTANCE, TIPC_CONN_MSG,
  				      BASIC_H_SIZE, msg_orignode(msg));
  			msg_set_errcode(msg, TIPC_ERR_NO_PORT);
  			msg_set_origport(msg, destport);
  			msg_set_destport(msg, msg_origport(msg));
  		}
  		if (p_ptr)
  			tipc_port_unlock(p_ptr);
  		goto exit;
  	}
  
  	/* Process protocol message sent by peer */
  	switch (msg_type(msg)) {
  	case CONN_ACK:
  		wakeable = tipc_port_congested(p_ptr) && p_ptr->congested &&
  			p_ptr->wakeup;
  		p_ptr->acked += msg_msgcnt(msg);
  		if (!tipc_port_congested(p_ptr)) {
  			p_ptr->congested = 0;
  			if (wakeable)
  				p_ptr->wakeup(p_ptr);
  		}
  		break;
  	case CONN_PROBE:
  		r_buf = port_build_proto_msg(p_ptr, CONN_PROBE_REPLY, 0);
  		break;
  	default:
  		/* CONN_PROBE_REPLY or unrecognized - no action required */
  		break;
  	}
  	p_ptr->probing_state = CONFIRMED;
  	tipc_port_unlock(p_ptr);
  exit:
  	tipc_net_route_msg(r_buf);
  	kfree_skb(buf);
  }
  
  static int port_print(struct tipc_port *p_ptr, char *buf, int len, int full_id)
  {
  	struct publication *publ;
  	int ret;
  
  	if (full_id)
  		ret = tipc_snprintf(buf, len, "<%u.%u.%u:%u>:",
  				    tipc_zone(tipc_own_addr),
  				    tipc_cluster(tipc_own_addr),
  				    tipc_node(tipc_own_addr), p_ptr->ref);
  	else
  		ret = tipc_snprintf(buf, len, "%-10u:", p_ptr->ref);
  
  	if (p_ptr->connected) {
  		u32 dport = port_peerport(p_ptr);
  		u32 destnode = port_peernode(p_ptr);
  
  		ret += tipc_snprintf(buf + ret, len - ret,
  				     " connected to <%u.%u.%u:%u>",
  				     tipc_zone(destnode),
  				     tipc_cluster(destnode),
  				     tipc_node(destnode), dport);
  		if (p_ptr->conn_type != 0)
  			ret += tipc_snprintf(buf + ret, len - ret,
  					     " via {%u,%u}", p_ptr->conn_type,
  					     p_ptr->conn_instance);
  	} else if (p_ptr->published) {
  		ret += tipc_snprintf(buf + ret, len - ret, " bound to");
  		list_for_each_entry(publ, &p_ptr->publications, pport_list) {
  			if (publ->lower == publ->upper)
  				ret += tipc_snprintf(buf + ret, len - ret,
  						     " {%u,%u}", publ->type,
  						     publ->lower);
  			else
  				ret += tipc_snprintf(buf + ret, len - ret,
  						     " {%u,%u,%u}", publ->type,
  						     publ->lower, publ->upper);
  		}
  	}
  	ret += tipc_snprintf(buf + ret, len - ret, "\n");
  	return ret;
  }
  
  struct sk_buff *tipc_port_get_ports(void)
  {
  	struct sk_buff *buf;
  	struct tlv_desc *rep_tlv;
  	char *pb;
  	int pb_len;
  	struct tipc_port *p_ptr;
  	int str_len = 0;
  
  	buf = tipc_cfg_reply_alloc(TLV_SPACE(ULTRA_STRING_MAX_LEN));
  	if (!buf)
  		return NULL;
  	rep_tlv = (struct tlv_desc *)buf->data;
  	pb = TLV_DATA(rep_tlv);
  	pb_len = ULTRA_STRING_MAX_LEN;
  
  	spin_lock_bh(&tipc_port_list_lock);
  	list_for_each_entry(p_ptr, &ports, port_list) {
  		spin_lock_bh(p_ptr->lock);
  		str_len += port_print(p_ptr, pb, pb_len, 0);
  		spin_unlock_bh(p_ptr->lock);
  	}
  	spin_unlock_bh(&tipc_port_list_lock);
  	str_len += 1;	/* for "\0" */
  	skb_put(buf, TLV_SPACE(str_len));
  	TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
  
  	return buf;
  }
  
  void tipc_port_reinit(void)
  {
  	struct tipc_port *p_ptr;
  	struct tipc_msg *msg;
  
  	spin_lock_bh(&tipc_port_list_lock);
  	list_for_each_entry(p_ptr, &ports, port_list) {
  		msg = &p_ptr->phdr;
  		msg_set_prevnode(msg, tipc_own_addr);
  		msg_set_orignode(msg, tipc_own_addr);
  	}
  	spin_unlock_bh(&tipc_port_list_lock);
  }
  
  void tipc_acknowledge(u32 ref, u32 ack)
  {
  	struct tipc_port *p_ptr;
  	struct sk_buff *buf = NULL;
  
  	p_ptr = tipc_port_lock(ref);
  	if (!p_ptr)
  		return;
  	if (p_ptr->connected) {
  		p_ptr->conn_unacked -= ack;
  		buf = port_build_proto_msg(p_ptr, CONN_ACK, ack);
  	}
  	tipc_port_unlock(p_ptr);
  	tipc_net_route_msg(buf);
  }
  
  int tipc_portimportance(u32 ref, unsigned int *importance)
  {
  	struct tipc_port *p_ptr;
  
  	p_ptr = tipc_port_lock(ref);
  	if (!p_ptr)
  		return -EINVAL;
  	*importance = (unsigned int)msg_importance(&p_ptr->phdr);
  	tipc_port_unlock(p_ptr);
  	return 0;
  }
  
  int tipc_set_portimportance(u32 ref, unsigned int imp)
  {
  	struct tipc_port *p_ptr;
  
  	if (imp > TIPC_CRITICAL_IMPORTANCE)
  		return -EINVAL;
  
  	p_ptr = tipc_port_lock(ref);
  	if (!p_ptr)
  		return -EINVAL;
  	msg_set_importance(&p_ptr->phdr, (u32)imp);
  	tipc_port_unlock(p_ptr);
  	return 0;
  }
  
  
  int tipc_publish(struct tipc_port *p_ptr, unsigned int scope,
  		 struct tipc_name_seq const *seq)
  {
  	struct publication *publ;
  	u32 key;
  
  	if (p_ptr->connected)
  		return -EINVAL;
  	key = p_ptr->ref + p_ptr->pub_count + 1;
  	if (key == p_ptr->ref)
  		return -EADDRINUSE;
  
  	publ = tipc_nametbl_publish(seq->type, seq->lower, seq->upper,
  				    scope, p_ptr->ref, key);
  	if (publ) {
  		list_add(&publ->pport_list, &p_ptr->publications);
  		p_ptr->pub_count++;
  		p_ptr->published = 1;
  		return 0;
  	}
  	return -EINVAL;
  }
  
  int tipc_withdraw(struct tipc_port *p_ptr, unsigned int scope,
  		  struct tipc_name_seq const *seq)
  {
  	struct publication *publ;
  	struct publication *tpubl;
  	int res = -EINVAL;
  
  	if (!seq) {
  		list_for_each_entry_safe(publ, tpubl,
  					 &p_ptr->publications, pport_list) {
  			tipc_nametbl_withdraw(publ->type, publ->lower,
  					      publ->ref, publ->key);
  		}
  		res = 0;
  	} else {
  		list_for_each_entry_safe(publ, tpubl,
  					 &p_ptr->publications, pport_list) {
  			if (publ->scope != scope)
  				continue;
  			if (publ->type != seq->type)
  				continue;
  			if (publ->lower != seq->lower)
  				continue;
  			if (publ->upper != seq->upper)
  				break;
  			tipc_nametbl_withdraw(publ->type, publ->lower,
  					      publ->ref, publ->key);
  			res = 0;
  			break;
  		}
  	}
  	if (list_empty(&p_ptr->publications))
  		p_ptr->published = 0;
  	return res;
  }
  
  int tipc_connect(u32 ref, struct tipc_portid const *peer)
  {
  	struct tipc_port *p_ptr;
  	int res;
  
  	p_ptr = tipc_port_lock(ref);
  	if (!p_ptr)
  		return -EINVAL;
  	res = __tipc_connect(ref, p_ptr, peer);
  	tipc_port_unlock(p_ptr);
  	return res;
  }
  
  /*
   * __tipc_connect - connect to a remote peer
   *
   * Port must be locked.
   */
  int __tipc_connect(u32 ref, struct tipc_port *p_ptr,
  			struct tipc_portid const *peer)
  {
  	struct tipc_msg *msg;
  	int res = -EINVAL;
  
  	if (p_ptr->published || p_ptr->connected)
  		goto exit;
  	if (!peer->ref)
  		goto exit;
  
  	msg = &p_ptr->phdr;
  	msg_set_destnode(msg, peer->node);
  	msg_set_destport(msg, peer->ref);
  	msg_set_type(msg, TIPC_CONN_MSG);
  	msg_set_lookup_scope(msg, 0);
  	msg_set_hdr_sz(msg, SHORT_H_SIZE);
  
  	p_ptr->probing_interval = PROBING_INTERVAL;
  	p_ptr->probing_state = CONFIRMED;
  	p_ptr->connected = 1;
  	k_start_timer(&p_ptr->timer, p_ptr->probing_interval);
  
  	tipc_nodesub_subscribe(&p_ptr->subscription, peer->node,
  			  (void *)(unsigned long)ref,
  			  (net_ev_handler)port_handle_node_down);
  	res = 0;
  exit:
  	p_ptr->max_pkt = tipc_link_get_max_pkt(peer->node, ref);
  	return res;
  }
  
  /*
   * __tipc_disconnect - disconnect port from peer
   *
   * Port must be locked.
   */
  int __tipc_disconnect(struct tipc_port *tp_ptr)
  {
  	if (tp_ptr->connected) {
  		tp_ptr->connected = 0;
  		/* let timer expire on it's own to avoid deadlock! */
  		tipc_nodesub_unsubscribe(&tp_ptr->subscription);
  		return 0;
  	}
  
  	return -ENOTCONN;
  }
  
  /*
   * tipc_disconnect(): Disconnect port form peer.
   *                    This is a node local operation.
   */
  int tipc_disconnect(u32 ref)
  {
  	struct tipc_port *p_ptr;
  	int res;
  
  	p_ptr = tipc_port_lock(ref);
  	if (!p_ptr)
  		return -EINVAL;
  	res = __tipc_disconnect(p_ptr);
  	tipc_port_unlock(p_ptr);
  	return res;
  }
  
  /*
   * tipc_shutdown(): Send a SHUTDOWN msg to peer and disconnect
   */
  int tipc_shutdown(u32 ref)
  {
  	struct tipc_port *p_ptr;
  	struct sk_buff *buf = NULL;
  
  	p_ptr = tipc_port_lock(ref);
  	if (!p_ptr)
  		return -EINVAL;
  
  	buf = port_build_peer_abort_msg(p_ptr, TIPC_CONN_SHUTDOWN);
  	tipc_port_unlock(p_ptr);
  	tipc_net_route_msg(buf);
  	return tipc_disconnect(ref);
  }
  
  /**
   * tipc_port_recv_msg - receive message from lower layer and deliver to port user
   */
  int tipc_port_recv_msg(struct sk_buff *buf)
  {
  	struct tipc_port *p_ptr;
  	struct tipc_msg *msg = buf_msg(buf);
  	u32 destport = msg_destport(msg);
  	u32 dsz = msg_data_sz(msg);
  	u32 err;
  
  	/* forward unresolved named message */
  	if (unlikely(!destport)) {
  		tipc_net_route_msg(buf);
  		return dsz;
  	}
  
  	/* validate destination & pass to port, otherwise reject message */
  	p_ptr = tipc_port_lock(destport);
  	if (likely(p_ptr)) {
  		err = p_ptr->dispatcher(p_ptr, buf);
  		tipc_port_unlock(p_ptr);
  		if (likely(!err))
  			return dsz;
  	} else {
  		err = TIPC_ERR_NO_PORT;
  	}
  
  	return tipc_reject_msg(buf, err);
  }
  
  /*
   *  tipc_port_recv_sections(): Concatenate and deliver sectioned
   *                        message for this node.
   */
  static int tipc_port_recv_sections(struct tipc_port *sender,
  				   struct iovec const *msg_sect,
  				   unsigned int len)
  {
  	struct sk_buff *buf;
  	int res;
  
  	res = tipc_msg_build(&sender->phdr, msg_sect, len, MAX_MSG_SIZE, &buf);
  	if (likely(buf))
  		tipc_port_recv_msg(buf);
  	return res;
  }
  
  /**
   * tipc_send - send message sections on connection
   */
  int tipc_send(u32 ref, struct iovec const *msg_sect, unsigned int len)
  {
  	struct tipc_port *p_ptr;
  	u32 destnode;
  	int res;
  
  	p_ptr = tipc_port_deref(ref);
  	if (!p_ptr || !p_ptr->connected)
  		return -EINVAL;
  
  	p_ptr->congested = 1;
  	if (!tipc_port_congested(p_ptr)) {
  		destnode = port_peernode(p_ptr);
  		if (likely(!in_own_node(destnode)))
  			res = tipc_link_send_sections_fast(p_ptr, msg_sect,
  							   len, destnode);
  		else
  			res = tipc_port_recv_sections(p_ptr, msg_sect, len);
  
  		if (likely(res != -ELINKCONG)) {
  			p_ptr->congested = 0;
  			if (res > 0)
  				p_ptr->sent++;
  			return res;
  		}
  	}
  	if (port_unreliable(p_ptr)) {
  		p_ptr->congested = 0;
  		return len;
  	}
  	return -ELINKCONG;
  }
  
  /**
   * tipc_send2name - send message sections to port name
   */
  int tipc_send2name(u32 ref, struct tipc_name const *name, unsigned int domain,
  		   struct iovec const *msg_sect, unsigned int len)
  {
  	struct tipc_port *p_ptr;
  	struct tipc_msg *msg;
  	u32 destnode = domain;
  	u32 destport;
  	int res;
  
  	p_ptr = tipc_port_deref(ref);
  	if (!p_ptr || p_ptr->connected)
  		return -EINVAL;
  
  	msg = &p_ptr->phdr;
  	msg_set_type(msg, TIPC_NAMED_MSG);
  	msg_set_hdr_sz(msg, NAMED_H_SIZE);
  	msg_set_nametype(msg, name->type);
  	msg_set_nameinst(msg, name->instance);
  	msg_set_lookup_scope(msg, tipc_addr_scope(domain));
  	destport = tipc_nametbl_translate(name->type, name->instance, &destnode);
  	msg_set_destnode(msg, destnode);
  	msg_set_destport(msg, destport);
  
  	if (likely(destport || destnode)) {
  		if (likely(in_own_node(destnode)))
  			res = tipc_port_recv_sections(p_ptr, msg_sect, len);
  		else if (tipc_own_addr)
  			res = tipc_link_send_sections_fast(p_ptr, msg_sect,
  							   len, destnode);
  		else
  			res = tipc_port_reject_sections(p_ptr, msg, msg_sect,
  							len, TIPC_ERR_NO_NODE);
  		if (likely(res != -ELINKCONG)) {
  			if (res > 0)
  				p_ptr->sent++;
  			return res;
  		}
  		if (port_unreliable(p_ptr)) {
  			return len;
  		}
  		return -ELINKCONG;
  	}
  	return tipc_port_reject_sections(p_ptr, msg, msg_sect, len,
  					 TIPC_ERR_NO_NAME);
  }
  
  /**
   * tipc_send2port - send message sections to port identity
   */
  int tipc_send2port(u32 ref, struct tipc_portid const *dest,
  		   struct iovec const *msg_sect, unsigned int len)
  {
  	struct tipc_port *p_ptr;
  	struct tipc_msg *msg;
  	int res;
  
  	p_ptr = tipc_port_deref(ref);
  	if (!p_ptr || p_ptr->connected)
  		return -EINVAL;
  
  	msg = &p_ptr->phdr;
  	msg_set_type(msg, TIPC_DIRECT_MSG);
  	msg_set_lookup_scope(msg, 0);
  	msg_set_destnode(msg, dest->node);
  	msg_set_destport(msg, dest->ref);
  	msg_set_hdr_sz(msg, BASIC_H_SIZE);
  
  	if (in_own_node(dest->node))
  		res =  tipc_port_recv_sections(p_ptr, msg_sect, len);
  	else if (tipc_own_addr)
  		res = tipc_link_send_sections_fast(p_ptr, msg_sect, len,
  						   dest->node);
  	else
  		res = tipc_port_reject_sections(p_ptr, msg, msg_sect, len,
  						TIPC_ERR_NO_NODE);
  	if (likely(res != -ELINKCONG)) {
  		if (res > 0)
  			p_ptr->sent++;
  		return res;
  	}
  	if (port_unreliable(p_ptr)) {
  		return len;
  	}
  	return -ELINKCONG;
  }
  