net/tipc/bcast.c - linux - Git at Google

 /*
  * net/tipc/bcast.c: TIPC broadcast code
  *
  * Copyright (c) 2004-2006, 2014-2016, Ericsson AB
  * Copyright (c) 2004, Intel Corporation.
  * Copyright (c) 2005, 2010-2011, 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/tipc_config.h>
 #include "socket.h"
 #include "msg.h"
 #include "bcast.h"
 #include "name_distr.h"
 #include "link.h"
 #include "node.h"

 #define	BCLINK_WIN_DEFAULT	50	/* bcast link window size (default) */
 #define	BCLINK_WIN_MIN	        32	/* bcast minimum link window size */

 const char tipc_bclink_name[] = "broadcast-link";

 /**
  * struct tipc_bc_base - base structure for keeping broadcast send state
  * @link: broadcast send link structure
  * @inputq: data input queue; will only carry SOCK_WAKEUP messages
  * @dest: array keeping number of reachable destinations per bearer
  * @primary_bearer: a bearer having links to all broadcast destinations, if any
  * @bcast_support: indicates if primary bearer, if any, supports broadcast
  */
 struct tipc_bc_base {
 	struct tipc_link *link;
 	struct sk_buff_head inputq;
 	int dests[MAX_BEARERS];
 	int primary_bearer;
 	bool bcast_support;
 };

 static struct tipc_bc_base *tipc_bc_base(struct net *net)
 {
 	return tipc_net(net)->bcbase;
 }

 int tipc_bcast_get_mtu(struct net *net)
 {
 	return tipc_link_mtu(tipc_bc_sndlink(net));
 }

 /* tipc_bcbase_select_primary(): find a bearer with links to all destinations,
  *                               if any, and make it primary bearer
  */
 static void tipc_bcbase_select_primary(struct net *net)
 {
 	struct tipc_bc_base *bb = tipc_bc_base(net);
 	int all_dests =  tipc_link_bc_peers(bb->link);
 	int i, mtu, prim;

 	bb->primary_bearer = INVALID_BEARER_ID;
 	bb->bcast_support = true;

 	if (!all_dests)
 		return;

 	for (i = 0; i < MAX_BEARERS; i++) {
 		if (!bb->dests[i])
 			continue;

 		mtu = tipc_bearer_mtu(net, i);
 		if (mtu < tipc_link_mtu(bb->link))
 			tipc_link_set_mtu(bb->link, mtu);
 		bb->bcast_support &= tipc_bearer_bcast_support(net, i);
 		if (bb->dests[i] < all_dests)
 			continue;

 		bb->primary_bearer = i;

 		/* Reduce risk that all nodes select same primary */
 		if ((i ^ tipc_own_addr(net)) & 1)
 			break;
 	}
 	prim = bb->primary_bearer;
 	if (prim != INVALID_BEARER_ID)
 		bb->bcast_support = tipc_bearer_bcast_support(net, prim);
 }

 void tipc_bcast_inc_bearer_dst_cnt(struct net *net, int bearer_id)
 {
 	struct tipc_bc_base *bb = tipc_bc_base(net);

 	tipc_bcast_lock(net);
 	bb->dests[bearer_id]++;
 	tipc_bcbase_select_primary(net);
 	tipc_bcast_unlock(net);
 }

 void tipc_bcast_dec_bearer_dst_cnt(struct net *net, int bearer_id)
 {
 	struct tipc_bc_base *bb = tipc_bc_base(net);

 	tipc_bcast_lock(net);
 	bb->dests[bearer_id]--;
 	tipc_bcbase_select_primary(net);
 	tipc_bcast_unlock(net);
 }

 /* tipc_bcbase_xmit - broadcast a packet queue across one or more bearers
  *
  * Note that number of reachable destinations, as indicated in the dests[]
  * array, may transitionally differ from the number of destinations indicated
  * in each sent buffer. We can sustain this. Excess destination nodes will
  * drop and never acknowledge the unexpected packets, and missing destinations
  * will either require retransmission (if they are just about to be added to
  * the bearer), or be removed from the buffer's 'ackers' counter (if they
  * just went down)
  */
 static void tipc_bcbase_xmit(struct net *net, struct sk_buff_head *xmitq)
 {
 	int bearer_id;
 	struct tipc_bc_base *bb = tipc_bc_base(net);
 	struct sk_buff *skb, *_skb;
 	struct sk_buff_head _xmitq;

 	if (skb_queue_empty(xmitq))
 		return;

 	/* The typical case: at least one bearer has links to all nodes */
 	bearer_id = bb->primary_bearer;
 	if (bearer_id >= 0) {
 		tipc_bearer_bc_xmit(net, bearer_id, xmitq);
 		return;
 	}

 	/* We have to transmit across all bearers */
 	skb_queue_head_init(&_xmitq);
 	for (bearer_id = 0; bearer_id < MAX_BEARERS; bearer_id++) {
 		if (!bb->dests[bearer_id])
 			continue;

 		skb_queue_walk(xmitq, skb) {
 			_skb = pskb_copy_for_clone(skb, GFP_ATOMIC);
 			if (!_skb)
 				break;
 			__skb_queue_tail(&_xmitq, _skb);
 		}
 		tipc_bearer_bc_xmit(net, bearer_id, &_xmitq);
 	}
 	__skb_queue_purge(xmitq);
 	__skb_queue_purge(&_xmitq);
 }

 /* tipc_bcast_xmit - deliver buffer chain to all nodes in cluster
  *                    and to identified node local sockets
  * @net: the applicable net namespace
  * @list: chain of buffers containing message
  * Consumes the buffer chain.
  * Returns 0 if success, otherwise errno: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE
  */
 int tipc_bcast_xmit(struct net *net, struct sk_buff_head *list)
 {
 	struct tipc_link *l = tipc_bc_sndlink(net);
 	struct sk_buff_head xmitq, inputq, rcvq;
 	int rc = 0;

 	__skb_queue_head_init(&rcvq);
 	__skb_queue_head_init(&xmitq);
 	skb_queue_head_init(&inputq);

 	/* Prepare message clone for local node */
 	if (unlikely(!tipc_msg_reassemble(list, &rcvq)))
 		return -EHOSTUNREACH;

 	tipc_bcast_lock(net);
 	if (tipc_link_bc_peers(l))
 		rc = tipc_link_xmit(l, list, &xmitq);
 	tipc_bcast_unlock(net);

 	/* Don't send to local node if adding to link failed */
 	if (unlikely(rc && (rc != -ELINKCONG))) {
 		__skb_queue_purge(&rcvq);
 		return rc;
 	}

 	/* Broadcast to all nodes, inluding local node */
 	tipc_bcbase_xmit(net, &xmitq);
 	tipc_sk_mcast_rcv(net, &rcvq, &inputq);
 	__skb_queue_purge(list);
 	return rc;
 }

 /* tipc_bcast_rcv - receive a broadcast packet, and deliver to rcv link
  *
  * RCU is locked, no other locks set
  */
 int tipc_bcast_rcv(struct net *net, struct tipc_link *l, struct sk_buff *skb)
 {
 	struct tipc_msg *hdr = buf_msg(skb);
 	struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
 	struct sk_buff_head xmitq;
 	int rc;

 	__skb_queue_head_init(&xmitq);

 	if (msg_mc_netid(hdr) != tipc_netid(net) || !tipc_link_is_up(l)) {
 		kfree_skb(skb);
 		return 0;
 	}

 	tipc_bcast_lock(net);
 	if (msg_user(hdr) == BCAST_PROTOCOL)
 		rc = tipc_link_bc_nack_rcv(l, skb, &xmitq);
 	else
 		rc = tipc_link_rcv(l, skb, NULL);
 	tipc_bcast_unlock(net);

 	tipc_bcbase_xmit(net, &xmitq);

 	/* Any socket wakeup messages ? */
 	if (!skb_queue_empty(inputq))
 		tipc_sk_rcv(net, inputq);

 	return rc;
 }

 /* tipc_bcast_ack_rcv - receive and handle a broadcast acknowledge
  *
  * RCU is locked, no other locks set
  */
 void tipc_bcast_ack_rcv(struct net *net, struct tipc_link *l,
 			struct tipc_msg *hdr)
 {
 	struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
 	u16 acked = msg_bcast_ack(hdr);
 	struct sk_buff_head xmitq;

 	/* Ignore bc acks sent by peer before bcast synch point was received */
 	if (msg_bc_ack_invalid(hdr))
 		return;

 	__skb_queue_head_init(&xmitq);

 	tipc_bcast_lock(net);
 	tipc_link_bc_ack_rcv(l, acked, &xmitq);
 	tipc_bcast_unlock(net);

 	tipc_bcbase_xmit(net, &xmitq);

 	/* Any socket wakeup messages ? */
 	if (!skb_queue_empty(inputq))
 		tipc_sk_rcv(net, inputq);
 }

 /* tipc_bcast_synch_rcv -  check and update rcv link with peer's send state
  *
  * RCU is locked, no other locks set
  */
 int tipc_bcast_sync_rcv(struct net *net, struct tipc_link *l,
 			struct tipc_msg *hdr)
 {
 	struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
 	struct sk_buff_head xmitq;
 	int rc = 0;

 	__skb_queue_head_init(&xmitq);

 	tipc_bcast_lock(net);
 	if (msg_type(hdr) != STATE_MSG) {
 		tipc_link_bc_init_rcv(l, hdr);
 	} else if (!msg_bc_ack_invalid(hdr)) {
 		tipc_link_bc_ack_rcv(l, msg_bcast_ack(hdr), &xmitq);
 		rc = tipc_link_bc_sync_rcv(l, hdr, &xmitq);
 	}
 	tipc_bcast_unlock(net);

 	tipc_bcbase_xmit(net, &xmitq);

 	/* Any socket wakeup messages ? */
 	if (!skb_queue_empty(inputq))
 		tipc_sk_rcv(net, inputq);
 	return rc;
 }

 /* tipc_bcast_add_peer - add a peer node to broadcast link and bearer
  *
  * RCU is locked, node lock is set
  */
 void tipc_bcast_add_peer(struct net *net, struct tipc_link *uc_l,
 			 struct sk_buff_head *xmitq)
 {
 	struct tipc_link *snd_l = tipc_bc_sndlink(net);

 	tipc_bcast_lock(net);
 	tipc_link_add_bc_peer(snd_l, uc_l, xmitq);
 	tipc_bcbase_select_primary(net);
 	tipc_bcast_unlock(net);
 }

 /* tipc_bcast_remove_peer - remove a peer node from broadcast link and bearer
  *
  * RCU is locked, node lock is set
  */
 void tipc_bcast_remove_peer(struct net *net, struct tipc_link *rcv_l)
 {
 	struct tipc_link *snd_l = tipc_bc_sndlink(net);
 	struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
 	struct sk_buff_head xmitq;

 	__skb_queue_head_init(&xmitq);

 	tipc_bcast_lock(net);
 	tipc_link_remove_bc_peer(snd_l, rcv_l, &xmitq);
 	tipc_bcbase_select_primary(net);
 	tipc_bcast_unlock(net);

 	tipc_bcbase_xmit(net, &xmitq);

 	/* Any socket wakeup messages ? */
 	if (!skb_queue_empty(inputq))
 		tipc_sk_rcv(net, inputq);
 }

 int tipc_bclink_reset_stats(struct net *net)
 {
 	struct tipc_link *l = tipc_bc_sndlink(net);

 	if (!l)
 		return -ENOPROTOOPT;

 	tipc_bcast_lock(net);
 	tipc_link_reset_stats(l);
 	tipc_bcast_unlock(net);
 	return 0;
 }

 static int tipc_bc_link_set_queue_limits(struct net *net, u32 limit)
 {
 	struct tipc_link *l = tipc_bc_sndlink(net);

 	if (!l)
 		return -ENOPROTOOPT;
 	if (limit < BCLINK_WIN_MIN)
 		limit = BCLINK_WIN_MIN;
 	if (limit > TIPC_MAX_LINK_WIN)
 		return -EINVAL;
 	tipc_bcast_lock(net);
 	tipc_link_set_queue_limits(l, limit);
 	tipc_bcast_unlock(net);
 	return 0;
 }

 int tipc_nl_bc_link_set(struct net *net, struct nlattr *attrs[])
 {
 	int err;
 	u32 win;
 	struct nlattr *props[TIPC_NLA_PROP_MAX + 1];

 	if (!attrs[TIPC_NLA_LINK_PROP])
 		return -EINVAL;

 	err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP], props);
 	if (err)
 		return err;

 	if (!props[TIPC_NLA_PROP_WIN])
 		return -EOPNOTSUPP;

 	win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);

 	return tipc_bc_link_set_queue_limits(net, win);
 }

 int tipc_bcast_init(struct net *net)
 {
 	struct tipc_net *tn = tipc_net(net);
 	struct tipc_bc_base *bb = NULL;
 	struct tipc_link *l = NULL;

 	bb = kzalloc(sizeof(*bb), GFP_ATOMIC);
 	if (!bb)
 		goto enomem;
 	tn->bcbase = bb;
 	spin_lock_init(&tipc_net(net)->bclock);

 	if (!tipc_link_bc_create(net, 0, 0,
 				 U16_MAX,
 				 BCLINK_WIN_DEFAULT,
 				 0,
 				 &bb->inputq,
 				 NULL,
 				 NULL,
 				 &l))
 		goto enomem;
 	bb->link = l;
 	tn->bcl = l;
 	return 0;
 enomem:
 	kfree(bb);
 	kfree(l);
 	return -ENOMEM;
 }

 void tipc_bcast_stop(struct net *net)
 {
 	struct tipc_net *tn = net_generic(net, tipc_net_id);

 	synchronize_net();
 	kfree(tn->bcbase);
 	kfree(tn->bcl);
 }
	/*
	* net/tipc/bcast.c: TIPC broadcast code
	*
	* Copyright (c) 2004-2006, 2014-2016, Ericsson AB
	* Copyright (c) 2004, Intel Corporation.
	* Copyright (c) 2005, 2010-2011, 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/tipc_config.h>
	#include "socket.h"
	#include "msg.h"
	#include "bcast.h"
	#include "name_distr.h"
	#include "link.h"
	#include "node.h"

	#define BCLINK_WIN_DEFAULT 50 /* bcast link window size (default) */
	#define BCLINK_WIN_MIN 32 /* bcast minimum link window size */

	const char tipc_bclink_name[] = "broadcast-link";

	/**
	* struct tipc_bc_base - base structure for keeping broadcast send state
	* @link: broadcast send link structure
	* @inputq: data input queue; will only carry SOCK_WAKEUP messages
	* @dest: array keeping number of reachable destinations per bearer
	* @primary_bearer: a bearer having links to all broadcast destinations, if any
	* @bcast_support: indicates if primary bearer, if any, supports broadcast
	*/
	struct tipc_bc_base {
	struct tipc_link *link;
	struct sk_buff_head inputq;
	int dests[MAX_BEARERS];
	int primary_bearer;
	bool bcast_support;
	};

	static struct tipc_bc_base tipc_bc_base(struct net net)
	{
	return tipc_net(net)->bcbase;
	}

	int tipc_bcast_get_mtu(struct net *net)
	{
	return tipc_link_mtu(tipc_bc_sndlink(net));
	}

	/* tipc_bcbase_select_primary(): find a bearer with links to all destinations,
	* if any, and make it primary bearer
	*/
	static void tipc_bcbase_select_primary(struct net *net)
	{
	struct tipc_bc_base *bb = tipc_bc_base(net);
	int all_dests = tipc_link_bc_peers(bb->link);
	int i, mtu, prim;

	bb->primary_bearer = INVALID_BEARER_ID;
	bb->bcast_support = true;

	if (!all_dests)
	return;

	for (i = 0; i < MAX_BEARERS; i++) {
	if (!bb->dests[i])
	continue;

	mtu = tipc_bearer_mtu(net, i);
	if (mtu < tipc_link_mtu(bb->link))
	tipc_link_set_mtu(bb->link, mtu);
	bb->bcast_support &= tipc_bearer_bcast_support(net, i);
	if (bb->dests[i] < all_dests)
	continue;

	bb->primary_bearer = i;

	/* Reduce risk that all nodes select same primary */
	if ((i ^ tipc_own_addr(net)) & 1)
	break;
	}
	prim = bb->primary_bearer;
	if (prim != INVALID_BEARER_ID)
	bb->bcast_support = tipc_bearer_bcast_support(net, prim);
	}

	void tipc_bcast_inc_bearer_dst_cnt(struct net *net, int bearer_id)
	{
	struct tipc_bc_base *bb = tipc_bc_base(net);

	tipc_bcast_lock(net);
	bb->dests[bearer_id]++;
	tipc_bcbase_select_primary(net);
	tipc_bcast_unlock(net);
	}

	void tipc_bcast_dec_bearer_dst_cnt(struct net *net, int bearer_id)
	{
	struct tipc_bc_base *bb = tipc_bc_base(net);

	tipc_bcast_lock(net);
	bb->dests[bearer_id]--;
	tipc_bcbase_select_primary(net);
	tipc_bcast_unlock(net);
	}

	/* tipc_bcbase_xmit - broadcast a packet queue across one or more bearers
	*
	* Note that number of reachable destinations, as indicated in the dests[]
	* array, may transitionally differ from the number of destinations indicated
	* in each sent buffer. We can sustain this. Excess destination nodes will
	* drop and never acknowledge the unexpected packets, and missing destinations
	* will either require retransmission (if they are just about to be added to
	* the bearer), or be removed from the buffer's 'ackers' counter (if they
	* just went down)
	*/
	static void tipc_bcbase_xmit(struct net net, struct sk_buff_head xmitq)
	{
	int bearer_id;
	struct tipc_bc_base *bb = tipc_bc_base(net);
	struct sk_buff skb, _skb;
	struct sk_buff_head _xmitq;

	if (skb_queue_empty(xmitq))
	return;

	/* The typical case: at least one bearer has links to all nodes */
	bearer_id = bb->primary_bearer;
	if (bearer_id >= 0) {
	tipc_bearer_bc_xmit(net, bearer_id, xmitq);
	return;
	}

	/* We have to transmit across all bearers */
	skb_queue_head_init(&_xmitq);
	for (bearer_id = 0; bearer_id < MAX_BEARERS; bearer_id++) {
	if (!bb->dests[bearer_id])
	continue;

	skb_queue_walk(xmitq, skb) {
	_skb = pskb_copy_for_clone(skb, GFP_ATOMIC);
	if (!_skb)
	break;
	__skb_queue_tail(&_xmitq, _skb);
	}
	tipc_bearer_bc_xmit(net, bearer_id, &_xmitq);
	}
	__skb_queue_purge(xmitq);
	__skb_queue_purge(&_xmitq);
	}

	/* tipc_bcast_xmit - deliver buffer chain to all nodes in cluster
	* and to identified node local sockets
	* @net: the applicable net namespace
	* @list: chain of buffers containing message
	* Consumes the buffer chain.
	* Returns 0 if success, otherwise errno: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE
	*/
	int tipc_bcast_xmit(struct net net, struct sk_buff_head list)
	{
	struct tipc_link *l = tipc_bc_sndlink(net);
	struct sk_buff_head xmitq, inputq, rcvq;
	int rc = 0;

	__skb_queue_head_init(&rcvq);
	__skb_queue_head_init(&xmitq);
	skb_queue_head_init(&inputq);

	/* Prepare message clone for local node */
	if (unlikely(!tipc_msg_reassemble(list, &rcvq)))
	return -EHOSTUNREACH;

	tipc_bcast_lock(net);
	if (tipc_link_bc_peers(l))
	rc = tipc_link_xmit(l, list, &xmitq);
	tipc_bcast_unlock(net);

	/* Don't send to local node if adding to link failed */
	if (unlikely(rc && (rc != -ELINKCONG))) {
	__skb_queue_purge(&rcvq);
	return rc;
	}

	/* Broadcast to all nodes, inluding local node */
	tipc_bcbase_xmit(net, &xmitq);
	tipc_sk_mcast_rcv(net, &rcvq, &inputq);
	__skb_queue_purge(list);
	return rc;
	}

	/* tipc_bcast_rcv - receive a broadcast packet, and deliver to rcv link
	*
	* RCU is locked, no other locks set
	*/
	int tipc_bcast_rcv(struct net net, struct tipc_link l, struct sk_buff *skb)
	{
	struct tipc_msg *hdr = buf_msg(skb);
	struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
	struct sk_buff_head xmitq;
	int rc;

	__skb_queue_head_init(&xmitq);

	if (msg_mc_netid(hdr) != tipc_netid(net) \|\| !tipc_link_is_up(l)) {
	kfree_skb(skb);
	return 0;
	}

	tipc_bcast_lock(net);
	if (msg_user(hdr) == BCAST_PROTOCOL)
	rc = tipc_link_bc_nack_rcv(l, skb, &xmitq);
	else
	rc = tipc_link_rcv(l, skb, NULL);
	tipc_bcast_unlock(net);

	tipc_bcbase_xmit(net, &xmitq);

	/* Any socket wakeup messages ? */
	if (!skb_queue_empty(inputq))
	tipc_sk_rcv(net, inputq);

	return rc;
	}

	/* tipc_bcast_ack_rcv - receive and handle a broadcast acknowledge
	*
	* RCU is locked, no other locks set
	*/
	void tipc_bcast_ack_rcv(struct net net, struct tipc_link l,
	struct tipc_msg *hdr)
	{
	struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
	u16 acked = msg_bcast_ack(hdr);
	struct sk_buff_head xmitq;

	/* Ignore bc acks sent by peer before bcast synch point was received */
	if (msg_bc_ack_invalid(hdr))
	return;

	__skb_queue_head_init(&xmitq);

	tipc_bcast_lock(net);
	tipc_link_bc_ack_rcv(l, acked, &xmitq);
	tipc_bcast_unlock(net);

	tipc_bcbase_xmit(net, &xmitq);

	/* Any socket wakeup messages ? */
	if (!skb_queue_empty(inputq))
	tipc_sk_rcv(net, inputq);
	}

	/* tipc_bcast_synch_rcv - check and update rcv link with peer's send state
	*
	* RCU is locked, no other locks set
	*/
	int tipc_bcast_sync_rcv(struct net net, struct tipc_link l,
	struct tipc_msg *hdr)
	{
	struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
	struct sk_buff_head xmitq;
	int rc = 0;

	__skb_queue_head_init(&xmitq);

	tipc_bcast_lock(net);
	if (msg_type(hdr) != STATE_MSG) {
	tipc_link_bc_init_rcv(l, hdr);
	} else if (!msg_bc_ack_invalid(hdr)) {
	tipc_link_bc_ack_rcv(l, msg_bcast_ack(hdr), &xmitq);
	rc = tipc_link_bc_sync_rcv(l, hdr, &xmitq);
	}
	tipc_bcast_unlock(net);

	tipc_bcbase_xmit(net, &xmitq);

	/* Any socket wakeup messages ? */
	if (!skb_queue_empty(inputq))
	tipc_sk_rcv(net, inputq);
	return rc;
	}

	/* tipc_bcast_add_peer - add a peer node to broadcast link and bearer
	*
	* RCU is locked, node lock is set
	*/
	void tipc_bcast_add_peer(struct net net, struct tipc_link uc_l,
	struct sk_buff_head *xmitq)
	{
	struct tipc_link *snd_l = tipc_bc_sndlink(net);

	tipc_bcast_lock(net);
	tipc_link_add_bc_peer(snd_l, uc_l, xmitq);
	tipc_bcbase_select_primary(net);
	tipc_bcast_unlock(net);
	}

	/* tipc_bcast_remove_peer - remove a peer node from broadcast link and bearer
	*
	* RCU is locked, node lock is set
	*/
	void tipc_bcast_remove_peer(struct net net, struct tipc_link rcv_l)
	{
	struct tipc_link *snd_l = tipc_bc_sndlink(net);
	struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
	struct sk_buff_head xmitq;

	__skb_queue_head_init(&xmitq);

	tipc_bcast_lock(net);
	tipc_link_remove_bc_peer(snd_l, rcv_l, &xmitq);
	tipc_bcbase_select_primary(net);
	tipc_bcast_unlock(net);

	tipc_bcbase_xmit(net, &xmitq);

	/* Any socket wakeup messages ? */
	if (!skb_queue_empty(inputq))
	tipc_sk_rcv(net, inputq);
	}

	int tipc_bclink_reset_stats(struct net *net)
	{
	struct tipc_link *l = tipc_bc_sndlink(net);

	if (!l)
	return -ENOPROTOOPT;

	tipc_bcast_lock(net);
	tipc_link_reset_stats(l);
	tipc_bcast_unlock(net);
	return 0;
	}

	static int tipc_bc_link_set_queue_limits(struct net *net, u32 limit)
	{
	struct tipc_link *l = tipc_bc_sndlink(net);

	if (!l)
	return -ENOPROTOOPT;
	if (limit < BCLINK_WIN_MIN)
	limit = BCLINK_WIN_MIN;
	if (limit > TIPC_MAX_LINK_WIN)
	return -EINVAL;
	tipc_bcast_lock(net);
	tipc_link_set_queue_limits(l, limit);
	tipc_bcast_unlock(net);
	return 0;
	}

	int tipc_nl_bc_link_set(struct net net, struct nlattr attrs[])
	{
	int err;
	u32 win;
	struct nlattr *props[TIPC_NLA_PROP_MAX + 1];

	if (!attrs[TIPC_NLA_LINK_PROP])
	return -EINVAL;

	err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP], props);
	if (err)
	return err;

	if (!props[TIPC_NLA_PROP_WIN])
	return -EOPNOTSUPP;

	win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);

	return tipc_bc_link_set_queue_limits(net, win);
	}

	int tipc_bcast_init(struct net *net)
	{
	struct tipc_net *tn = tipc_net(net);
	struct tipc_bc_base *bb = NULL;
	struct tipc_link *l = NULL;

	bb = kzalloc(sizeof(*bb), GFP_ATOMIC);
	if (!bb)
	goto enomem;
	tn->bcbase = bb;
	spin_lock_init(&tipc_net(net)->bclock);

	if (!tipc_link_bc_create(net, 0, 0,
	U16_MAX,
	BCLINK_WIN_DEFAULT,
	0,
	&bb->inputq,
	NULL,
	NULL,
	&l))
	goto enomem;
	bb->link = l;
	tn->bcl = l;
	return 0;
	enomem:
	kfree(bb);
	kfree(l);
	return -ENOMEM;
	}

	void tipc_bcast_stop(struct net *net)
	{
	struct tipc_net *tn = net_generic(net, tipc_net_id);

	synchronize_net();
	kfree(tn->bcbase);
	kfree(tn->bcl);
	}