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/net/tipc/link.c

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/*
 * net/tipc/link.c: TIPC link code
 *
 * Copyright (c) 1996-2007, Ericsson AB
 * Copyright (c) 2004-2007, 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 "dbg.h"
#include "link.h"
#include "net.h"
#include "node.h"
#include "port.h"
#include "addr.h"
#include "node_subscr.h"
#include "name_distr.h"
#include "bearer.h"
#include "name_table.h"
#include "discover.h"
#include "config.h"
#include "bcast.h"


/*
 * Out-of-range value for link session numbers
 */

#define INVALID_SESSION 0x10000

/*
 * Limit for deferred reception queue:
 */

#define DEF_QUEUE_LIMIT 256u

/*
 * Link state events:
 */

#define  STARTING_EVT    856384768	/* link processing trigger */
#define  TRAFFIC_MSG_EVT 560815u	/* rx'd ??? */
#define  TIMEOUT_EVT     560817u	/* link timer expired */

/*
 * The following two 'message types' is really just implementation
 * data conveniently stored in the message header.
 * They must not be considered part of the protocol
 */
#define OPEN_MSG   0
#define CLOSED_MSG 1

/*
 * State value stored in 'exp_msg_count'
 */

#define START_CHANGEOVER 100000u

/**
 * struct link_name - deconstructed link name
 * @addr_local: network address of node at this end
 * @if_local: name of interface at this end
 * @addr_peer: network address of node at far end
 * @if_peer: name of interface at far end
 */

struct link_name {
	u32 addr_local;
	char if_local[TIPC_MAX_IF_NAME];
	u32 addr_peer;
	char if_peer[TIPC_MAX_IF_NAME];
};

#if 0

/* LINK EVENT CODE IS NOT SUPPORTED AT PRESENT */

/**
 * struct link_event - link up/down event notification
 */

struct link_event {
	u32 addr;
	int up;
	void (*fcn)(u32, char *, int);
	char name[TIPC_MAX_LINK_NAME];
};

#endif

static void link_handle_out_of_seq_msg(struct link *l_ptr,
				       struct sk_buff *buf);
static void link_recv_proto_msg(struct link *l_ptr, struct sk_buff *buf);
static int  link_recv_changeover_msg(struct link **l_ptr, struct sk_buff **buf);
static void link_set_supervision_props(struct link *l_ptr, u32 tolerance);
static int  link_send_sections_long(struct port *sender,
				    struct iovec const *msg_sect,
				    u32 num_sect, u32 destnode);
static void link_check_defragm_bufs(struct link *l_ptr);
static void link_state_event(struct link *l_ptr, u32 event);
static void link_reset_statistics(struct link *l_ptr);
static void link_print(struct link *l_ptr, struct print_buf *buf,
		       const char *str);

/*
 * Debugging code used by link routines only
 *
 * When debugging link problems on a system that has multiple links,
 * the standard TIPC debugging routines may not be useful since they
 * allow the output from multiple links to be intermixed.  For this reason
 * routines of the form "dbg_link_XXX()" have been created that will capture
 * debug info into a link's personal print buffer, which can then be dumped
 * into the TIPC system log (TIPC_LOG) upon request.
 *
 * To enable per-link debugging, use LINK_LOG_BUF_SIZE to specify the size
 * of the print buffer used by each link.  If LINK_LOG_BUF_SIZE is set to 0,
 * the dbg_link_XXX() routines simply send their output to the standard
 * debug print buffer (DBG_OUTPUT), if it has been defined; this can be useful
 * when there is only a single link in the system being debugged.
 *
 * Notes:
 * - When enabled, LINK_LOG_BUF_SIZE should be set to at least TIPC_PB_MIN_SIZE
 * - "l_ptr" must be valid when using dbg_link_XXX() macros
 */

#define LINK_LOG_BUF_SIZE 0

#define dbg_link(fmt, arg...) \
	do { \
		if (LINK_LOG_BUF_SIZE) \
			tipc_printf(&l_ptr->print_buf, fmt, ## arg); \
	} while (0)
#define dbg_link_msg(msg, txt) \
	do { \
		if (LINK_LOG_BUF_SIZE) \
			tipc_msg_dbg(&l_ptr->print_buf, msg, txt); \
	} while (0)
#define dbg_link_state(txt) \
	do { \
		if (LINK_LOG_BUF_SIZE) \
			link_print(l_ptr, &l_ptr->print_buf, txt); \
	} while (0)
#define dbg_link_dump() do { \
	if (LINK_LOG_BUF_SIZE) { \
		tipc_printf(LOG, "\n\nDumping link <%s>:\n", l_ptr->name); \
		tipc_printbuf_move(LOG, &l_ptr->print_buf); \
	} \
} while (0)

static void dbg_print_link(struct link *l_ptr, const char *str)
{
	if (DBG_OUTPUT != TIPC_NULL)
		link_print(l_ptr, DBG_OUTPUT, str);
}

static void dbg_print_buf_chain(struct sk_buff *root_buf)
{
	if (DBG_OUTPUT != TIPC_NULL) {
		struct sk_buff *buf = root_buf;

		while (buf) {
			msg_dbg(buf_msg(buf), "In chain: ");
			buf = buf->next;
		}
	}
}

/*
 *  Simple link routines
 */

static unsigned int align(unsigned int i)
{
	return (i + 3) & ~3u;
}

static int link_working_working(struct link *l_ptr)
{
	return (l_ptr->state == WORKING_WORKING);
}

static int link_working_unknown(struct link *l_ptr)
{
	return (l_ptr->state == WORKING_UNKNOWN);
}

static int link_reset_unknown(struct link *l_ptr)
{
	return (l_ptr->state == RESET_UNKNOWN);
}

static int link_reset_reset(struct link *l_ptr)
{
	return (l_ptr->state == RESET_RESET);
}

static int link_blocked(struct link *l_ptr)
{
	return (l_ptr->exp_msg_count || l_ptr->blocked);
}

static int link_congested(struct link *l_ptr)
{
	return (l_ptr->out_queue_size >= l_ptr->queue_limit[0]);
}

static u32 link_max_pkt(struct link *l_ptr)
{
	return l_ptr->max_pkt;
}

static void link_init_max_pkt(struct link *l_ptr)
{
	u32 max_pkt;

	max_pkt = (l_ptr->b_ptr->publ.mtu & ~3);
	if (max_pkt > MAX_MSG_SIZE)
		max_pkt = MAX_MSG_SIZE;

	l_ptr->max_pkt_target = max_pkt;
	if (l_ptr->max_pkt_target < MAX_PKT_DEFAULT)
		l_ptr->max_pkt = l_ptr->max_pkt_target;
	else
		l_ptr->max_pkt = MAX_PKT_DEFAULT;

	l_ptr->max_pkt_probes = 0;
}

static u32 link_next_sent(struct link *l_ptr)
{
	if (l_ptr->next_out)
		return msg_seqno(buf_msg(l_ptr->next_out));
	return mod(l_ptr->next_out_no);
}

static u32 link_last_sent(struct link *l_ptr)
{
	return mod(link_next_sent(l_ptr) - 1);
}

/*
 *  Simple non-static link routines (i.e. referenced outside this file)
 */

int tipc_link_is_up(struct link *l_ptr)
{
	if (!l_ptr)
		return 0;
	return (link_working_working(l_ptr) || link_working_unknown(l_ptr));
}

int tipc_link_is_active(struct link *l_ptr)
{
	return ((l_ptr->owner->active_links[0] == l_ptr) ||
		(l_ptr->owner->active_links[1] == l_ptr));
}

/**
 * link_name_validate - validate & (optionally) deconstruct link name
 * @name - ptr to link name string
 * @name_parts - ptr to area for link name components (or NULL if not needed)
 *
 * Returns 1 if link name is valid, otherwise 0.
 */

static int link_name_validate(const char *name, struct link_name *name_parts)
{
	char name_copy[TIPC_MAX_LINK_NAME];
	char *addr_local;
	char *if_local;
	char *addr_peer;
	char *if_peer;
	char dummy;
	u32 z_local, c_local, n_local;
	u32 z_peer, c_peer, n_peer;
	u32 if_local_len;
	u32 if_peer_len;

	/* copy link name & ensure length is OK */

	name_copy[TIPC_MAX_LINK_NAME - 1] = 0;
	/* need above in case non-Posix strncpy() doesn't pad with nulls */
	strncpy(name_copy, name, TIPC_MAX_LINK_NAME);
	if (name_copy[TIPC_MAX_LINK_NAME - 1] != 0)
		return 0;

	/* ensure all component parts of link name are present */

	addr_local = name_copy;
	if ((if_local = strchr(addr_local, ':')) == NULL)
		return 0;
	*(if_local++) = 0;
	if ((addr_peer = strchr(if_local, '-')) == NULL)
		return 0;
	*(addr_peer++) = 0;
	if_local_len = addr_peer - if_local;
	if ((if_peer = strchr(addr_peer, ':')) == NULL)
		return 0;
	*(if_peer++) = 0;
	if_peer_len = strlen(if_peer) + 1;

	/* validate component parts of link name */

	if ((sscanf(addr_local, "%u.%u.%u%c",
		    &z_local, &c_local, &n_local, &dummy) != 3) ||
	    (sscanf(addr_peer, "%u.%u.%u%c",
		    &z_peer, &c_peer, &n_peer, &dummy) != 3) ||
	    (z_local > 255) || (c_local > 4095) || (n_local > 4095) ||
	    (z_peer  > 255) || (c_peer  > 4095) || (n_peer  > 4095) ||
	    (if_local_len <= 1) || (if_local_len > TIPC_MAX_IF_NAME) ||
	    (if_peer_len  <= 1) || (if_peer_len  > TIPC_MAX_IF_NAME) ||
	    (strspn(if_local, tipc_alphabet) != (if_local_len - 1)) ||
	    (strspn(if_peer, tipc_alphabet) != (if_peer_len - 1)))
		return 0;

	/* return link name components, if necessary */

	if (name_parts) {
		name_parts->addr_local = tipc_addr(z_local, c_local, n_local);
		strcpy(name_parts->if_local, if_local);
		name_parts->addr_peer = tipc_addr(z_peer, c_peer, n_peer);
		strcpy(name_parts->if_peer, if_peer);
	}
	return 1;
}

/**
 * link_timeout - handle expiration of link timer
 * @l_ptr: pointer to link
 *
 * This routine must not grab "tipc_net_lock" to avoid a potential deadlock conflict
 * with tipc_link_delete().  (There is no risk that the node will be deleted by
 * another thread because tipc_link_delete() always cancels the link timer before
 * tipc_node_delete() is called.)
 */

static void link_timeout(struct link *l_ptr)
{
	tipc_node_lock(l_ptr->owner);

	/* update counters used in statistical profiling of send traffic */

	l_ptr->stats.accu_queue_sz += l_ptr->out_queue_size;
	l_ptr->stats.queue_sz_counts++;

	if (l_ptr->out_queue_size > l_ptr->stats.max_queue_sz)
		l_ptr->stats.max_queue_sz = l_ptr->out_queue_size;

	if (l_ptr->first_out) {
		struct tipc_msg *msg = buf_msg(l_ptr->first_out);
		u32 length = msg_size(msg);

		if ((msg_user(msg) == MSG_FRAGMENTER) &&
		    (msg_type(msg) == FIRST_FRAGMENT)) {
			length = msg_size(msg_get_wrapped(msg));
		}
		if (length) {
			l_ptr->stats.msg_lengths_total += length;
			l_ptr->stats.msg_length_counts++;
			if (length <= 64)
				l_ptr->stats.msg_length_profile[0]++;
			else if (length <= 256)
				l_ptr->stats.msg_length_profile[1]++;
			else if (length <= 1024)
				l_ptr->stats.msg_length_profile[2]++;
			else if (length <= 4096)
				l_ptr->stats.msg_length_profile[3]++;
			else if (length <= 16384)
				l_ptr->stats.msg_length_profile[4]++;
			else if (length <= 32768)
				l_ptr->stats.msg_length_profile[5]++;
			else
				l_ptr->stats.msg_length_profile[6]++;
		}
	}

	/* do all other link processing performed on a periodic basis */

	link_check_defragm_bufs(l_ptr);

	link_state_event(l_ptr, TIMEOUT_EVT);

	if (l_ptr->next_out)
		tipc_link_push_queue(l_ptr);

	tipc_node_unlock(l_ptr->owner);
}

static void link_set_timer(struct link *l_ptr, u32 time)
{
	k_start_timer(&l_ptr->timer, time);
}

/**
 * tipc_link_create - create a new link
 * @b_ptr: pointer to associated bearer
 * @peer: network address of node at other end of link
 * @media_addr: media address to use when sending messages over link
 *
 * Returns pointer to link.
 */

struct link *tipc_link_create(struct bearer *b_ptr, const u32 peer,
			      const struct tipc_media_addr *media_addr)
{
	struct link *l_ptr;
	struct tipc_msg *msg;
	char *if_name;

	l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
	if (!l_ptr) {
		warn("Link creation failed, no memory\n");
		return NULL;
	}

	if (LINK_LOG_BUF_SIZE) {
		char *pb = kmalloc(LINK_LOG_BUF_SIZE, GFP_ATOMIC);

		if (!pb) {
			kfree(l_ptr);
			warn("Link creation failed, no memory for print buffer\n");
			return NULL;
		}
		tipc_printbuf_init(&l_ptr->print_buf, pb, LINK_LOG_BUF_SIZE);
	}

	l_ptr->addr = peer;
	if_name = strchr(b_ptr->publ.name, ':') + 1;
	sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:",
		tipc_zone(tipc_own_addr), tipc_cluster(tipc_own_addr),
		tipc_node(tipc_own_addr),
		if_name,
		tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
		/* note: peer i/f is appended to link name by reset/activate */
	memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
	l_ptr->checkpoint = 1;
	l_ptr->b_ptr = b_ptr;
	link_set_supervision_props(l_ptr, b_ptr->media->tolerance);
	l_ptr->state = RESET_UNKNOWN;

	l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
	msg = l_ptr->pmsg;
	msg_init(msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, l_ptr->addr);
	msg_set_size(msg, sizeof(l_ptr->proto_msg));
	msg_set_session(msg, (tipc_random & 0xffff));
	msg_set_bearer_id(msg, b_ptr->identity);
	strcpy((char *)msg_data(msg), if_name);

	l_ptr->priority = b_ptr->priority;
	tipc_link_set_queue_limits(l_ptr, b_ptr->media->window);

	link_init_max_pkt(l_ptr);

	l_ptr->next_out_no = 1;
	INIT_LIST_HEAD(&l_ptr->waiting_ports);

	link_reset_statistics(l_ptr);

	l_ptr->owner = tipc_node_attach_link(l_ptr);
	if (!l_ptr->owner) {
		if (LINK_LOG_BUF_SIZE)
			kfree(l_ptr->print_buf.buf);
		kfree(l_ptr);
		return NULL;
	}

	k_init_timer(&l_ptr->timer, (Handler)link_timeout, (unsigned long)l_ptr);
	list_add_tail(&l_ptr->link_list, &b_ptr->links);
	tipc_k_signal((Handler)tipc_link_start, (unsigned long)l_ptr);

	dbg("tipc_link_create(): tolerance = %u,cont intv = %u, abort_limit = %u\n",
	    l_ptr->tolerance, l_ptr->continuity_interval, l_ptr->abort_limit);

	return l_ptr;
}

/**
 * tipc_link_delete - delete a link
 * @l_ptr: pointer to link
 *
 * Note: 'tipc_net_lock' is write_locked, bearer is locked.
 * This routine must not grab the node lock until after link timer cancellation
 * to avoid a potential deadlock situation.
 */

void tipc_link_delete(struct link *l_ptr)
{
	if (!l_ptr) {
		err("Attempt to delete non-existent link\n");
		return;
	}

	dbg("tipc_link_delete()\n");

	k_cancel_timer(&l_ptr->timer);

	tipc_node_lock(l_ptr->owner);
	tipc_link_reset(l_ptr);
	tipc_node_detach_link(l_ptr->owner, l_ptr);
	tipc_link_stop(l_ptr);
	list_del_init(&l_ptr->link_list);
	if (LINK_LOG_BUF_SIZE)
		kfree(l_ptr->print_buf.buf);
	tipc_node_unlock(l_ptr->owner);
	k_term_timer(&l_ptr->timer);
	kfree(l_ptr);
}

void tipc_link_start(struct link *l_ptr)
{
	dbg("tipc_link_start %x\n", l_ptr);
	link_state_event(l_ptr, STARTING_EVT);
}

/**
 * link_schedule_port - schedule port for deferred sending
 * @l_ptr: pointer to link
 * @origport: reference to sending port
 * @sz: amount of data to be sent
 *
 * Schedules port for renewed sending of messages after link congestion
 * has abated.
 */

static int link_schedule_port(struct link *l_ptr, u32 origport, u32 sz)
{
	struct port *p_ptr;

	spin_lock_bh(&tipc_port_list_lock);
	p_ptr = tipc_port_lock(origport);
	if (p_ptr) {
		if (!p_ptr->wakeup)
			goto exit;
		if (!list_empty(&p_ptr->wait_list))
			goto exit;
		p_ptr->congested_link = l_ptr;
		p_ptr->publ.congested = 1;
		p_ptr->waiting_pkts = 1 + ((sz - 1) / link_max_pkt(l_ptr));
		list_add_tail(&p_ptr->wait_list, &l_ptr->waiting_ports);
		l_ptr->stats.link_congs++;
exit:
		tipc_port_unlock(p_ptr);
	}
	spin_unlock_bh(&tipc_port_list_lock);
	return -ELINKCONG;
}

void tipc_link_wakeup_ports(struct link *l_ptr, int all)
{
	struct port *p_ptr;
	struct port *temp_p_ptr;
	int win = l_ptr->queue_limit[0] - l_ptr->out_queue_size;

	if (all)
		win = 100000;
	if (win <= 0)
		return;
	if (!spin_trylock_bh(&tipc_port_list_lock))
		return;
	if (link_congested(l_ptr))
		goto exit;
	list_for_each_entry_safe(p_ptr, temp_p_ptr, &l_ptr->waiting_ports,
				 wait_list) {
		if (win <= 0)
			break;
		list_del_init(&p_ptr->wait_list);
		p_ptr->congested_link = NULL;
		spin_lock_bh(p_ptr->publ.lock);
		p_ptr->publ.congested = 0;
		p_ptr->wakeup(&p_ptr->publ);
		win -= p_ptr->waiting_pkts;
		spin_unlock_bh(p_ptr->publ.lock);
	}

exit:
	spin_unlock_bh(&tipc_port_list_lock);
}

/**
 * link_release_outqueue - purge link's outbound message queue
 * @l_ptr: pointer to link
 */

static void link_release_outqueue(struct link *l_ptr)
{
	struct sk_buff *buf = l_ptr->first_out;
	struct sk_buff *next;

	while (buf) {
		next = buf->next;
		buf_discard(buf);
		buf = next;
	}
	l_ptr->first_out = NULL;
	l_ptr->out_queue_size = 0;
}

/**
 * tipc_link_reset_fragments - purge link's inbound message fragments queue
 * @l_ptr: pointer to link
 */

void tipc_link_reset_fragments(struct link *l_ptr)
{
	struct sk_buff *buf = l_ptr->defragm_buf;
	struct sk_buff *next;

	while (buf) {
		next = buf->next;
		buf_discard(buf);
		buf = next;
	}
	l_ptr->defragm_buf = NULL;
}

/**
 * tipc_link_stop - purge all inbound and outbound messages associated with link
 * @l_ptr: pointer to link
 */

void tipc_link_stop(struct link *l_ptr)
{
	struct sk_buff *buf;
	struct sk_buff *next;

	buf = l_ptr->oldest_deferred_in;
	while (buf) {
		next = buf->next;
		buf_discard(buf);
		buf = next;
	}

	buf = l_ptr->first_out;
	while (buf) {
		next = buf->next;
		buf_discard(buf);
		buf = next;
	}

	tipc_link_reset_fragments(l_ptr);

	buf_discard(l_ptr->proto_msg_queue);
	l_ptr->proto_msg_queue = NULL;
}

#if 0

/* LINK EVENT CODE IS NOT SUPPORTED AT PRESENT */

static void link_recv_event(struct link_event *ev)
{
	ev->fcn(ev->addr, ev->name, ev->up);
	kfree(ev);
}

static void link_send_event(void (*fcn)(u32 a, char *n, int up),
			    struct link *l_ptr, int up)
{
	struct link_event *ev;

	ev = kmalloc(sizeof(*ev), GFP_ATOMIC);
	if (!ev) {
		warn("Link event allocation failure\n");
		return;
	}
	ev->addr = l_ptr->addr;
	ev->up = up;
	ev->fcn = fcn;
	memcpy(ev->name, l_ptr->name, TIPC_MAX_LINK_NAME);
	tipc_k_signal((Handler)link_recv_event, (unsigned long)ev);
}

#else

#define link_send_event(fcn, l_ptr, up) do { } while (0)

#endif

void tipc_link_reset(struct link *l_ptr)
{
	struct sk_buff *buf;
	u32 prev_state = l_ptr->state;
	u32 checkpoint = l_ptr->next_in_no;
	int was_active_link = tipc_link_is_active(l_ptr);

	msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));

	/* Link is down, accept any session */
	l_ptr->peer_session = INVALID_SESSION;

	/* Prepare for max packet size negotiation */
	link_init_max_pkt(l_ptr);

	l_ptr->state = RESET_UNKNOWN;
	dbg_link_state("Resetting Link\n");

	if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
		return;

	tipc_node_link_down(l_ptr->owner, l_ptr);
	tipc_bearer_remove_dest(l_ptr->b_ptr, l_ptr->addr);
#if 0
	tipc_printf(TIPC_CONS, "\nReset link <%s>\n", l_ptr->name);
	dbg_link_dump();
#endif
	if (was_active_link && tipc_node_has_active_links(l_ptr->owner) &&
	    l_ptr->owner->permit_changeover) {
		l_ptr->reset_checkpoint = checkpoint;
		l_ptr->exp_msg_count = START_CHANGEOVER;
	}

	/* Clean up all queues: */

	link_release_outqueue(l_ptr);
	buf_discard(l_ptr->proto_msg_queue);
	l_ptr->proto_msg_queue = NULL;
	buf = l_ptr->oldest_deferred_in;
	while (buf) {
		struct sk_buff *next = buf->next;
		buf_discard(buf);
		buf = next;
	}
	if (!list_empty(&l_ptr->waiting_ports))
		tipc_link_wakeup_ports(l_ptr, 1);

	l_ptr->retransm_queue_head = 0;
	l_ptr->retransm_queue_size = 0;
	l_ptr->last_out = NULL;
	l_ptr->first_out = NULL;
	l_ptr->next_out = NULL;
	l_ptr->unacked_window = 0;
	l_ptr->checkpoint = 1;
	l_ptr->next_out_no = 1;
	l_ptr->deferred_inqueue_sz = 0;
	l_ptr->oldest_deferred_in = NULL;
	l_ptr->newest_deferred_in = NULL;
	l_ptr->fsm_msg_cnt = 0;
	l_ptr->stale_count = 0;
	link_reset_statistics(l_ptr);

	link_send_event(tipc_cfg_link_event, l_ptr, 0);
	if (!in_own_cluster(l_ptr->addr))
		link_send_event(tipc_disc_link_event, l_ptr, 0);
}


static void link_activate(struct link *l_ptr)
{
	l_ptr->next_in_no = l_ptr->stats.recv_info = 1;
	tipc_node_link_up(l_ptr->owner, l_ptr);
	tipc_bearer_add_dest(l_ptr->b_ptr, l_ptr->addr);
	link_send_event(tipc_cfg_link_event, l_ptr, 1);
	if (!in_own_cluster(l_ptr->addr))
		link_send_event(tipc_disc_link_event, l_ptr, 1);
}

/**
 * link_state_event - link finite state machine
 * @l_ptr: pointer to link
 * @event: state machine event to process
 */

static void link_state_event(struct link *l_ptr, unsigned event)
{
	struct link *other;
	u32 cont_intv = l_ptr->continuity_interval;

	if (!l_ptr->started && (event != STARTING_EVT))
		return;		/* Not yet. */

	if (link_blocked(l_ptr)) {
		if (event == TIMEOUT_EVT) {
			link_set_timer(l_ptr, cont_intv);
		}
		return;	  /* Changeover going on */
	}
	dbg_link("STATE_EV: <%s> ", l_ptr->name);

	switch (l_ptr->state) {
	case WORKING_WORKING:
		dbg_link("WW/");
		switch (event) {
		case TRAFFIC_MSG_EVT:
			dbg_link("TRF-");
			/* fall through */
		case ACTIVATE_MSG:
			dbg_link("ACT\n");
			break;
		case TIMEOUT_EVT:
			dbg_link("TIM ");
			if (l_ptr->next_in_no != l_ptr->checkpoint) {
				l_ptr->checkpoint = l_ptr->next_in_no;
				if (tipc_bclink_acks_missing(l_ptr->owner)) {
					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
								 0, 0, 0, 0, 0);
					l_ptr->fsm_msg_cnt++;
				} else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
								 1, 0, 0, 0, 0);
					l_ptr->fsm_msg_cnt++;
				}
				link_set_timer(l_ptr, cont_intv);
				break;
			}
			dbg_link(" -> WU\n");
			l_ptr->state = WORKING_UNKNOWN;
			l_ptr->fsm_msg_cnt = 0;
			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
			l_ptr->fsm_msg_cnt++;
			link_set_timer(l_ptr, cont_intv / 4);
			break;
		case RESET_MSG:
			dbg_link("RES -> RR\n");
			info("Resetting link <%s>, requested by peer\n",
			     l_ptr->name);
			tipc_link_reset(l_ptr);
			l_ptr->state = RESET_RESET;
			l_ptr->fsm_msg_cnt = 0;
			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
			l_ptr->fsm_msg_cnt++;
			link_set_timer(l_ptr, cont_intv);
			break;
		default:
			err("Unknown link event %u in WW state\n", event);
		}
		break;
	case WORKING_UNKNOWN:
		dbg_link("WU/");
		switch (event) {
		case TRAFFIC_MSG_EVT:
			dbg_link("TRF-");
		case ACTIVATE_MSG:
			dbg_link("ACT -> WW\n");
			l_ptr->state = WORKING_WORKING;
			l_ptr->fsm_msg_cnt = 0;
			link_set_timer(l_ptr, cont_intv);
			break;
		case RESET_MSG:
			dbg_link("RES -> RR\n");
			info("Resetting link <%s>, requested by peer "
			     "while probing\n", l_ptr->name);
			tipc_link_reset(l_ptr);
			l_ptr->state = RESET_RESET;
			l_ptr->fsm_msg_cnt = 0;
			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
			l_ptr->fsm_msg_cnt++;
			link_set_timer(l_ptr, cont_intv);
			break;
		case TIMEOUT_EVT:
			dbg_link("TIM ");
			if (l_ptr->next_in_no != l_ptr->checkpoint) {
				dbg_link("-> WW \n");
				l_ptr->state = WORKING_WORKING;
				l_ptr->fsm_msg_cnt = 0;
				l_ptr->checkpoint = l_ptr->next_in_no;
				if (tipc_bclink_acks_missing(l_ptr->owner)) {
					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
								 0, 0, 0, 0, 0);
					l_ptr->fsm_msg_cnt++;
				}
				link_set_timer(l_ptr, cont_intv);
			} else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
				dbg_link("Probing %u/%u,timer = %u ms)\n",
					 l_ptr->fsm_msg_cnt, l_ptr->abort_limit,
					 cont_intv / 4);
				tipc_link_send_proto_msg(l_ptr, STATE_MSG,
							 1, 0, 0, 0, 0);
				l_ptr->fsm_msg_cnt++;
				link_set_timer(l_ptr, cont_intv / 4);
			} else {	/* Link has failed */
				dbg_link("-> RU (%u probes unanswered)\n",
					 l_ptr->fsm_msg_cnt);
				warn("Resetting link <%s>, peer not responding\n",
				     l_ptr->name);
				tipc_link_reset(l_ptr);
				l_ptr->state = RESET_UNKNOWN;
				l_ptr->fsm_msg_cnt = 0;
				tipc_link_send_proto_msg(l_ptr, RESET_MSG,
							 0, 0, 0, 0, 0);
				l_ptr->fsm_msg_cnt++;
				link_set_timer(l_ptr, cont_intv);
			}
			break;
		default:
			err("Unknown link event %u in WU state\n", event);
		}
		break;
	case RESET_UNKNOWN:
		dbg_link("RU/");
		switch (event) {
		case TRAFFIC_MSG_EVT:
			dbg_link("TRF-\n");
			break;
		case ACTIVATE_MSG:
			other = l_ptr->owner->active_links[0];
			if (other && link_working_unknown(other)) {
				dbg_link("ACT\n");
				break;
			}
			dbg_link("ACT -> WW\n");
			l_ptr->state = WORKING_WORKING;
			l_ptr->fsm_msg_cnt = 0;
			link_activate(l_ptr);
			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
			l_ptr->fsm_msg_cnt++;
			link_set_timer(l_ptr, cont_intv);
			break;
		case RESET_MSG:
			dbg_link("RES \n");
			dbg_link(" -> RR\n");
			l_ptr->state = RESET_RESET;
			l_ptr->fsm_msg_cnt = 0;
			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 1, 0, 0, 0, 0);
			l_ptr->fsm_msg_cnt++;
			link_set_timer(l_ptr, cont_intv);
			break;
		case STARTING_EVT:
			dbg_link("START-");
			l_ptr->started = 1;
			/* fall through */
		case TIMEOUT_EVT:
			dbg_link("TIM \n");
			tipc_link_send_proto_msg(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
			l_ptr->fsm_msg_cnt++;
			link_set_timer(l_ptr, cont_intv);
			break;
		default:
			err("Unknown link event %u in RU state\n", event);
		}
		break;
	case RESET_RESET:
		dbg_link("RR/ ");
		switch (event) {
		case TRAFFIC_MSG_EVT:
			dbg_link("TRF-");
			/* fall through */
		case ACTIVATE_MSG:
			other = l_ptr->owner->active_links[0];
			if (other && link_working_unknown(other)) {
				dbg_link("ACT\n");
				break;
			}
			dbg_link("ACT -> WW\n");
			l_ptr->state = WORKING_WORKING;
			l_ptr->fsm_msg_cnt = 0;
			link_activate(l_ptr);
			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
			l_ptr->fsm_msg_cnt++;
			link_set_timer(l_ptr, cont_intv);
			break;
		case RESET_MSG:
			dbg_link("RES\n");
			break;
		case TIMEOUT_EVT:
			dbg_link("TIM\n");
			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
			l_ptr->fsm_msg_cnt++;
			link_set_timer(l_ptr, cont_intv);
			dbg_link("fsm_msg_cnt %u\n", l_ptr->fsm_msg_cnt);
			break;
		default:
			err("Unknown link event %u in RR state\n", event);
		}
		break;
	default:
		err("Unknown link state %u/%u\n", l_ptr->state, event);
	}
}

/*
 * link_bundle_buf(): Append contents of a buffer to
 * the tail of an existing one.
 */

static int link_bundle_buf(struct link *l_ptr,
			   struct sk_buff *bundler,
			   struct sk_buff *buf)
{
	struct tipc_msg *bundler_msg = buf_msg(bundler);
	struct tipc_msg *msg = buf_msg(buf);
	u32 size = msg_size(msg);
	u32 bundle_size = msg_size(bundler_msg);
	u32 to_pos = align(bundle_size);
	u32 pad = to_pos - bundle_size;

	if (msg_user(bundler_msg) != MSG_BUNDLER)
		return 0;
	if (msg_type(bundler_msg) != OPEN_MSG)
		return 0;
	if (skb_tailroom(bundler) < (pad + size))
		return 0;
	if (link_max_pkt(l_ptr) < (to_pos + size))
		return 0;

	skb_put(bundler, pad + size);
	skb_copy_to_linear_data_offset(bundler, to_pos, buf->data, size);
	msg_set_size(bundler_msg, to_pos + size);
	msg_set_msgcnt(bundler_msg, msg_msgcnt(bundler_msg) + 1);
	dbg("Packed msg # %u(%u octets) into pos %u in buf(#%u)\n",
	    msg_msgcnt(bundler_msg), size, to_pos, msg_seqno(bundler_msg));
	msg_dbg(msg, "PACKD:");
	buf_discard(buf);
	l_ptr->stats.sent_bundled++;
	return 1;
}

static void link_add_to_outqueue(struct link *l_ptr,
				 struct sk_buff *buf,
				 struct tipc_msg *msg)
{
	u32 ack = mod(l_ptr->next_in_no - 1);
	u32 seqno = mod(l_ptr->next_out_no++);

	msg_set_word(msg, 2, ((ack << 16) | seqno));
	msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
	buf->next = NULL;
	if (l_ptr->first_out) {
		l_ptr->last_out->next = buf;
		l_ptr->last_out = buf;
	} else
		l_ptr->first_out = l_ptr->last_out = buf;
	l_ptr->out_queue_size++;
}

/*
 * tipc_link_send_buf() is the 'full path' for messages, called from
 * inside TIPC when the 'fast path' in tipc_send_buf
 * has failed, and from link_send()
 */

int tipc_link_send_buf(struct link *l_ptr, struct sk_buff *buf)
{
	struct tipc_msg *msg = buf_msg(buf);
	u32 size = msg_size(msg);
	u32 dsz = msg_data_sz(msg);
	u32 queue_size = l_ptr->out_queue_size;
	u32 imp = msg_tot_importance(msg);
	u32 queue_limit = l_ptr->queue_limit[imp];
	u32 max_packet = link_max_pkt(l_ptr);

	msg_set_prevnode(msg, tipc_own_addr);	/* If routed message */

	/* Match msg importance against queue limits: */

	if (unlikely(queue_size >= queue_limit)) {
		if (imp <= TIPC_CRITICAL_IMPORTANCE) {
			return link_schedule_port(l_ptr, msg_origport(msg),
						  size);
		}
		msg_dbg(msg, "TIPC: Congestion, throwing away\n");
		buf_discard(buf);
		if (imp > CONN_MANAGER) {
			warn("Resetting link <%s>, send queue full", l_ptr->name);
			tipc_link_reset(l_ptr);
		}
		return dsz;
	}

	/* Fragmentation needed ? */

	if (size > max_packet)
		return tipc_link_send_long_buf(l_ptr, buf);

	/* Packet can be queued or sent: */

	if (queue_size > l_ptr->stats.max_queue_sz)
		l_ptr->stats.max_queue_sz = queue_size;

	if (likely(!tipc_bearer_congested(l_ptr->b_ptr, l_ptr) &&
		   !link_congested(l_ptr))) {
		link_add_to_outqueue(l_ptr, buf, msg);

		if (likely(tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr))) {
			l_ptr->unacked_window = 0;
		} else {
			tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
			l_ptr->stats.bearer_congs++;
			l_ptr->next_out = buf;
		}
		return dsz;
	}
	/* Congestion: can message be bundled ?: */

	if ((msg_user(msg) != CHANGEOVER_PROTOCOL) &&
	    (msg_user(msg) != MSG_FRAGMENTER)) {

		/* Try adding message to an existing bundle */

		if (l_ptr->next_out &&
		    link_bundle_buf(l_ptr, l_ptr->last_out, buf)) {
			tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
			return dsz;
		}

		/* Try creating a new bundle */

		if (size <= max_packet * 2 / 3) {
			struct sk_buff *bundler = buf_acquire(max_packet);
			struct tipc_msg bundler_hdr;

			if (bundler) {
				msg_init(&bundler_hdr, MSG_BUNDLER, OPEN_MSG,
					 INT_H_SIZE, l_ptr->addr);
				skb_copy_to_linear_data(bundler, &bundler_hdr,
							INT_H_SIZE);
				skb_trim(bundler, INT_H_SIZE);
				link_bundle_buf(l_ptr, bundler, buf);
				buf = bundler;
				msg = buf_msg(buf);
				l_ptr->stats.sent_bundles++;
			}
		}
	}
	if (!l_ptr->next_out)
		l_ptr->next_out = buf;
	link_add_to_outqueue(l_ptr, buf, msg);
	tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
	return dsz;
}

/*
 * tipc_link_send(): same as tipc_link_send_buf(), but the link to use has
 * not been selected yet, and the the owner node is not locked
 * Called by TIPC internal users, e.g. the name distributor
 */

int tipc_link_send(struct sk_buff *buf, u32 dest, u32 selector)
{
	struct link *l_ptr;
	struct tipc_node *n_ptr;
	int res = -ELINKCONG;

	read_lock_bh(&tipc_net_lock);
	n_ptr = tipc_node_select(dest, selector);
	if (n_ptr) {
		tipc_node_lock(n_ptr);
		l_ptr = n_ptr->active_links[selector & 1];
		if (l_ptr) {
			dbg("tipc_link_send: found link %x for dest %x\n", l_ptr, dest);
			res = tipc_link_send_buf(l_ptr, buf);
		} else {
			dbg("Attempt to send msg to unreachable node:\n");
			msg_dbg(buf_msg(buf),">>>");
			buf_discard(buf);
		}
		tipc_node_unlock(n_ptr);
	} else {
		dbg("Attempt to send msg to unknown node:\n");
		msg_dbg(buf_msg(buf),">>>");
		buf_discard(buf);
	}
	read_unlock_bh(&tipc_net_lock);
	return res;
}

/*
 * link_send_buf_fast: Entry for data messages where the
 * destination link is known and the header is complete,
 * inclusive total message length. Very time critical.
 * Link is locked. Returns user data length.
 */

static int link_send_buf_fast(struct link *l_ptr, struct sk_buff *buf,
			      u32 *used_max_pkt)
{
	struct tipc_msg *msg = buf_msg(buf);
	int res = msg_data_sz(msg);

	if (likely(!link_congested(l_ptr))) {
		if (likely(msg_size(msg) <= link_max_pkt(l_ptr))) {
			if (likely(list_empty(&l_ptr->b_ptr->cong_links))) {
				link_add_to_outqueue(l_ptr, buf, msg);
				if (likely(tipc_bearer_send(l_ptr->b_ptr, buf,
							    &l_ptr->media_addr))) {
					l_ptr->unacked_window = 0;
					msg_dbg(msg,"SENT_FAST:");
					return res;
				}
				dbg("failed sent fast...\n");
				tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
				l_ptr->stats.bearer_congs++;
				l_ptr->next_out = buf;
				return res;
			}
		}
		else
			*used_max_pkt = link_max_pkt(l_ptr);
	}
	return tipc_link_send_buf(l_ptr, buf);  /* All other cases */
}

/*
 * tipc_send_buf_fast: Entry for data messages where the
 * destination node is known and the header is complete,
 * inclusive total message length.
 * Returns user data length.
 */
int tipc_send_buf_fast(struct sk_buff *buf, u32 destnode)
{
	struct link *l_ptr;
	struct tipc_node *n_ptr;
	int res;
	u32 selector = msg_origport(buf_msg(buf)) & 1;
	u32 dummy;

	if (destnode == tipc_own_addr)
		return tipc_port_recv_msg(buf);

	read_lock_bh(&tipc_net_lock);
	n_ptr = tipc_node_select(destnode, selector);
	if (likely(n_ptr)) {
		tipc_node_lock(n_ptr);
		l_ptr = n_ptr->active_links[selector];
		dbg("send_fast: buf %x selected %x, destnode = %x\n",
		    buf, l_ptr, destnode);
		if (likely(l_ptr)) {
			res = link_send_buf_fast(l_ptr, buf, &dummy);
			tipc_node_unlock(n_ptr);
			read_unlock_bh(&tipc_net_lock);
			return res;
		}
		tipc_node_unlock(n_ptr);
	}
	read_unlock_bh(&tipc_net_lock);
	res = msg_data_sz(buf_msg(buf));
	tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
	return res;
}


/*
 * tipc_link_send_sections_fast: Entry for messages where the
 * destination processor is known and the header is complete,
 * except for total message length.
 * Returns user data length or errno.
 */
int tipc_link_send_sections_fast(struct port *sender,
				 struct iovec const *msg_sect,
				 const u32 num_sect,
				 u32 destaddr)
{
	struct tipc_msg *hdr = &sender->publ.phdr;
	struct link *l_ptr;
	struct sk_buff *buf;
	struct tipc_node *node;
	int res;
	u32 selector = msg_origport(hdr) & 1;

again:
	/*
	 * Try building message using port's max_pkt hint.
	 * (Must not hold any locks while building message.)
	 */

	res = msg_build(hdr, msg_sect, num_sect, sender->publ.max_pkt,
			!sender->user_port, &buf);

	read_lock_bh(&tipc_net_lock);
	node = tipc_node_select(destaddr, selector);
	if (likely(node)) {
		tipc_node_lock(node);
		l_ptr = node->active_links[selector];
		if (likely(l_ptr)) {
			if (likely(buf)) {
				res = link_send_buf_fast(l_ptr, buf,
							 &sender->publ.max_pkt);
				if (unlikely(res < 0))
					buf_discard(buf);
exit:
				tipc_node_unlock(node);
				read_unlock_bh(&tipc_net_lock);
				return res;
			}

			/* Exit if build request was invalid */

			if (unlikely(res < 0))
				goto exit;

			/* Exit if link (or bearer) is congested */

			if (link_congested(l_ptr) ||
			    !list_empty(&l_ptr->b_ptr->cong_links)) {
				res = link_schedule_port(l_ptr,
							 sender->publ.ref, res);
				goto exit;
			}

			/*
			 * Message size exceeds max_pkt hint; update hint,
			 * then re-try fast path or fragment the message
			 */

			sender->publ.max_pkt = link_max_pkt(l_ptr);
			tipc_node_unlock(node);
			read_unlock_bh(&tipc_net_lock);


			if ((msg_hdr_sz(hdr) + res) <= sender->publ.max_pkt)
				goto again;

			return link_send_sections_long(sender, msg_sect,
						       num_sect, destaddr);
		}
		tipc_node_unlock(node);
	}
	read_unlock_bh(&tipc_net_lock);

	/* Couldn't find a link to the destination node */

	if (buf)
		return tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
	if (res >= 0)
		return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
						 TIPC_ERR_NO_NODE);
	return res;
}

/*
 * link_send_sections_long(): Entry for long messages where the
 * destination node is known and the header is complete,
 * inclusive total message length.
 * Link and bearer congestion status have been checked to be ok,
 * and are ignored if they change.
 *
 * Note that fragments do not use the full link MTU so that they won't have
 * to undergo refragmentation if link changeover causes them to be sent
 * over another link with an additional tunnel header added as prefix.
 * (Refragmentation will still occur if the other link has a smaller MTU.)
 *
 * Returns user data length or errno.
 */
static int link_send_sections_long(struct port *sender,
				   struct iovec const *msg_sect,
				   u32 num_sect,
				   u32 destaddr)
{
	struct link *l_ptr;
	struct tipc_node *node;
	struct tipc_msg *hdr = &sender->publ.phdr;
	u32 dsz = msg_data_sz(hdr);
	u32 max_pkt,fragm_sz,rest;
	struct tipc_msg fragm_hdr;
	struct sk_buff *buf,*buf_chain,*prev;
	u32 fragm_crs,fragm_rest,hsz,sect_rest;
	const unchar *sect_crs;
	int curr_sect;
	u32 fragm_no;

again:
	fragm_no = 1;
	max_pkt = sender->publ.max_pkt - INT_H_SIZE;
		/* leave room for tunnel header in case of link changeover */
	fragm_sz = max_pkt - INT_H_SIZE;
		/* leave room for fragmentation header in each fragment */
	rest = dsz;
	fragm_crs = 0;
	fragm_rest = 0;
	sect_rest = 0;
	sect_crs = NULL;
	curr_sect = -1;

	/* Prepare reusable fragment header: */

	msg_dbg(hdr, ">FRAGMENTING>");
	msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
		 INT_H_SIZE, msg_destnode(hdr));
	msg_set_link_selector(&fragm_hdr, sender->publ.ref);
	msg_set_size(&fragm_hdr, max_pkt);
	msg_set_fragm_no(&fragm_hdr, 1);

	/* Prepare header of first fragment: */

	buf_chain = buf = buf_acquire(max_pkt);
	if (!buf)
		return -ENOMEM;
	buf->next = NULL;
	skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
	hsz = msg_hdr_sz(hdr);
	skb_copy_to_linear_data_offset(buf, INT_H_SIZE, hdr, hsz);
	msg_dbg(buf_msg(buf), ">BUILD>");

	/* Chop up message: */

	fragm_crs = INT_H_SIZE + hsz;
	fragm_rest = fragm_sz - hsz;

	do {		/* For all sections */
		u32 sz;

		if (!sect_rest) {
			sect_rest = msg_sect[++curr_sect].iov_len;
			sect_crs = (const unchar *)msg_sect[curr_sect].iov_base;
		}

		if (sect_rest < fragm_rest)
			sz = sect_rest;
		else
			sz = fragm_rest;

		if (likely(!sender->user_port)) {
			if (copy_from_user(buf->data + fragm_crs, sect_crs, sz)) {
error:
				for (; buf_chain; buf_chain = buf) {
					buf = buf_chain->next;
					buf_discard(buf_chain);
				}
				return -EFAULT;
			}
		} else
			skb_copy_to_linear_data_offset(buf, fragm_crs,
						       sect_crs, sz);
		sect_crs += sz;
		sect_rest -= sz;
		fragm_crs += sz;
		fragm_rest -= sz;
		rest -= sz;

		if (!fragm_rest && rest) {

			/* Initiate new fragment: */
			if (rest <= fragm_sz) {
				fragm_sz = rest;
				msg_set_type(&fragm_hdr,LAST_FRAGMENT);
			} else {
				msg_set_type(&fragm_hdr, FRAGMENT);
			}
			msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
			msg_set_fragm_no(&fragm_hdr, ++fragm_no);
			prev = buf;
			buf = buf_acquire(fragm_sz + INT_H_SIZE);
			if (!buf)
				goto error;

			buf->next = NULL;
			prev->next = buf;
			skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
			fragm_crs = INT_H_SIZE;
			fragm_rest = fragm_sz;
			msg_dbg(buf_msg(buf),"  >BUILD>");
		}
	}
	while (rest > 0);

	/*
	 * Now we have a buffer chain. Select a link and check
	 * that packet size is still OK
	 */
	node = tipc_node_select(destaddr, sender->publ.ref & 1);
	if (likely(node)) {
		tipc_node_lock(node);
		l_ptr = node->active_links[sender->publ.ref & 1];
		if (!l_ptr) {
			tipc_node_unlock(node);
			goto reject;
		}
		if (link_max_pkt(l_ptr) < max_pkt) {
			sender->publ.max_pkt = link_max_pkt(l_ptr);
			tipc_node_unlock(node);
			for (; buf_chain; buf_chain = buf) {
				buf = buf_chain->next;
				buf_discard(buf_chain);
			}
			goto again;
		}
	} else {
reject:
		for (; buf_chain; buf_chain = buf) {
			buf = buf_chain->next;
			buf_discard(buf_chain);
		}
		return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
						 TIPC_ERR_NO_NODE);
	}

	/* Append whole chain to send queue: */

	buf = buf_chain;
	l_ptr->long_msg_seq_no = mod(l_ptr->long_msg_seq_no + 1);
	if (!l_ptr->next_out)
		l_ptr->next_out = buf_chain;
	l_ptr->stats.sent_fragmented++;
	while (buf) {
		struct sk_buff *next = buf->next;
		struct tipc_msg *msg = buf_msg(buf);

		l_ptr->stats.sent_fragments++;
		msg_set_long_msgno(msg, l_ptr->long_msg_seq_no);
		link_add_to_outqueue(l_ptr, buf, msg);
		msg_dbg(msg, ">ADD>");
		buf = next;
	}

	/* Send it, if possible: */

	tipc_link_push_queue(l_ptr);
	tipc_node_unlock(node);
	return dsz;
}

/*
 * tipc_link_push_packet: Push one unsent packet to the media
 */
u32 tipc_link_push_packet(struct link *l_ptr)
{
	struct sk_buff *buf = l_ptr->first_out;
	u32 r_q_size = l_ptr->retransm_queue_size;
	u32 r_q_head = l_ptr->retransm_queue_head;

	/* Step to position where retransmission failed, if any,    */
	/* consider that buffers may have been released in meantime */

	if (r_q_size && buf) {
		u32 last = lesser(mod(r_q_head + r_q_size),
				  link_last_sent(l_ptr));
		u32 first = msg_seqno(buf_msg(buf));

		while (buf && less(first, r_q_head)) {
			first = mod(first + 1);
			buf = buf->next;
		}
		l_ptr->retransm_queue_head = r_q_head = first;
		l_ptr->retransm_queue_size = r_q_size = mod(last - first);
	}

	/* Continue retransmission now, if there is anything: */

	if (r_q_size && buf && !skb_cloned(buf)) {
		msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
		msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
		if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
			msg_dbg(buf_msg(buf), ">DEF-RETR>");
			l_ptr->retransm_queue_head = mod(++r_q_head);
			l_ptr->retransm_queue_size = --r_q_size;
			l_ptr->stats.retransmitted++;
			return 0;
		} else {
			l_ptr->stats.bearer_congs++;
			msg_dbg(buf_msg(buf), "|>DEF-RETR>");
			return PUSH_FAILED;
		}
	}

	/* Send deferred protocol message, if any: */

	buf = l_ptr->proto_msg_queue;
	if (buf) {
		msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
		msg_set_bcast_ack(buf_msg(buf),l_ptr->owner->bclink.last_in);
		if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
			msg_dbg(buf_msg(buf), ">DEF-PROT>");
			l_ptr->unacked_window = 0;
			buf_discard(buf);
			l_ptr->proto_msg_queue = NULL;
			return 0;
		} else {
			msg_dbg(buf_msg(buf), "|>DEF-PROT>");
			l_ptr->stats.bearer_congs++;
			return PUSH_FAILED;
		}
	}

	/* Send one deferred data message, if send window not full: */

	buf = l_ptr->next_out;
	if (buf) {
		struct tipc_msg *msg = buf_msg(buf);
		u32 next = msg_seqno(msg);
		u32 first = msg_seqno(buf_msg(l_ptr->first_out));

		if (mod(next - first) < l_ptr->queue_limit[0]) {
			msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
			msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
			if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
				if (msg_user(msg) == MSG_BUNDLER)
					msg_set_type(msg, CLOSED_MSG);
				msg_dbg(msg, ">PUSH-DATA>");
				l_ptr->next_out = buf->next;
				return 0;
			} else {
				msg_dbg(msg, "|PUSH-DATA|");
				l_ptr->stats.bearer_congs++;
				return PUSH_FAILED;
			}
		}
	}
	return PUSH_FINISHED;
}

/*
 * push_queue(): push out the unsent messages of a link where
 *               congestion has abated. Node is locked
 */
void tipc_link_push_queue(struct link *l_ptr)
{
	u32 res;

	if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr))
		return;

	do {
		res = tipc_link_push_packet(l_ptr);
	} while (!res);

	if (res == PUSH_FAILED)
		tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
}

static void link_reset_all(unsigned long addr)
{
	struct tipc_node *n_ptr;
	char addr_string[16];
	u32 i;

	read_lock_bh(&tipc_net_lock);
	n_ptr = tipc_node_find((u32)addr);
	if (!n_ptr) {
		read_unlock_bh(&tipc_net_lock);
		return;	/* node no longer exists */
	}

	tipc_node_lock(n_ptr);

	warn("Resetting all links to %s\n",
	     addr_string_fill(addr_string, n_ptr->addr));

	for (i = 0; i < MAX_BEARERS; i++) {
		if (n_ptr->links[i]) {
			link_print(n_ptr->links[i], TIPC_OUTPUT,
				   "Resetting link\n");
			tipc_link_reset(n_ptr->links[i]);
		}
	}

	tipc_node_unlock(n_ptr);
	read_unlock_bh(&tipc_net_lock);
}

static void link_retransmit_failure(struct link *l_ptr, struct sk_buff *buf)
{
	struct tipc_msg *msg = buf_msg(buf);

	warn("Retransmission failure on link <%s>\n", l_ptr->name);
	tipc_msg_dbg(TIPC_OUTPUT, msg, ">RETR-FAIL>");

	if (l_ptr->addr) {

		/* Handle failure on standard link */

		link_print(l_ptr, TIPC_OUTPUT, "Resetting link\n");
		tipc_link_reset(l_ptr);

	} else {

		/* Handle failure on broadcast link */

		struct tipc_node *n_ptr;
		char addr_string[16];

		tipc_printf(TIPC_OUTPUT, "Msg seq number: %u,  ", msg_seqno(msg));
		tipc_printf(TIPC_OUTPUT, "Outstanding acks: %lu\n",
				     (unsigned long) TIPC_SKB_CB(buf)->handle);

		n_ptr = l_ptr->owner->next;
		tipc_node_lock(n_ptr);

		addr_string_fill(addr_string, n_ptr->addr);
		tipc_printf(TIPC_OUTPUT, "Multicast link info for %s\n", addr_string);
		tipc_printf(TIPC_OUTPUT, "Supported: %d,  ", n_ptr->bclink.supported);
		tipc_printf(TIPC_OUTPUT, "Acked: %u\n", n_ptr->bclink.acked);
		tipc_printf(TIPC_OUTPUT, "Last in: %u,  ", n_ptr->bclink.last_in);
		tipc_printf(TIPC_OUTPUT, "Gap after: %u,  ", n_ptr->bclink.gap_after);
		tipc_printf(TIPC_OUTPUT, "Gap to: %u\n", n_ptr->bclink.gap_to);
		tipc_printf(TIPC_OUTPUT, "Nack sync: %u\n\n", n_ptr->bclink.nack_sync);

		tipc_k_signal((Handler)link_reset_all, (unsigned long)n_ptr->addr);

		tipc_node_unlock(n_ptr);

		l_ptr->stale_count = 0;
	}
}

void tipc_link_retransmit(struct link *l_ptr, struct sk_buff *buf,
			  u32 retransmits)
{
	struct tipc_msg *msg;

	if (!buf)
		return;

	msg = buf_msg(buf);

	dbg("Retransmitting %u in link %x\n", retransmits, l_ptr);

	if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
		if (!skb_cloned(buf)) {
			msg_dbg(msg, ">NO_RETR->BCONG>");
			dbg_print_link(l_ptr, "   ");
			l_ptr->retransm_queue_head = msg_seqno(msg);
			l_ptr->retransm_queue_size = retransmits;
			return;
		} else {
			/* Don't retransmit if driver already has the buffer */
		}
	} else {
		/* Detect repeated retransmit failures on uncongested bearer */

		if (l_ptr->last_retransmitted == msg_seqno(msg)) {
			if (++l_ptr->stale_count > 100) {
				link_retransmit_failure(l_ptr, buf);
				return;
			}
		} else {
			l_ptr->last_retransmitted = msg_seqno(msg);
			l_ptr->stale_count = 1;
		}
	}

	while (retransmits && (buf != l_ptr->next_out) && buf && !skb_cloned(buf)) {
		msg = buf_msg(buf);
		msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
		msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
		if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
			msg_dbg(buf_msg(buf), ">RETR>");
			buf = buf->next;
			retransmits--;
			l_ptr->stats.retransmitted++;
		} else {
			tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
			l_ptr->stats.bearer_congs++;
			l_ptr->retransm_queue_head = msg_seqno(buf_msg(buf));
			l_ptr->retransm_queue_size = retransmits;
			return;
		}
	}

	l_ptr->retransm_queue_head = l_ptr->retransm_queue_size = 0;
}

/**
 * link_insert_deferred_queue - insert deferred messages back into receive chain
 */

static struct sk_buff *link_insert_deferred_queue(struct link *l_ptr,
						  struct sk_buff *buf)
{
	u32 seq_no;

	if (l_ptr->oldest_deferred_in == NULL)
		return buf;

	seq_no = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
	if (seq_no == mod(l_ptr->next_in_no)) {
		l_ptr->newest_deferred_in->next = buf;
		buf = l_ptr->oldest_deferred_in;
		l_ptr->oldest_deferred_in = NULL;
		l_ptr->deferred_inqueue_sz = 0;
	}
	return buf;
}

/**
 * link_recv_buf_validate - validate basic format of received message
 *
 * This routine ensures a TIPC message has an acceptable header, and at least
 * as much data as the header indicates it should.  The routine also ensures
 * that the entire message header is stored in the main fragment of the message
 * buffer, to simplify future access to message header fields.
 *
 * Note: Having extra info present in the message header or data areas is OK.
 * TIPC will ignore the excess, under the assumption that it is optional info
 * introduced by a later release of the protocol.
 */

static int link_recv_buf_validate(struct sk_buff *buf)
{
	static u32 min_data_hdr_size[8] = {
		SHORT_H_SIZE, MCAST_H_SIZE, LONG_H_SIZE, DIR_MSG_H_SIZE,
		MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE
		};

	struct tipc_msg *msg;
	u32 tipc_hdr[2];
	u32 size;
	u32 hdr_size;
	u32 min_hdr_size;

	if (unlikely(buf->len < MIN_H_SIZE))
		return 0;

	msg = skb_header_pointer(buf, 0, sizeof(tipc_hdr), tipc_hdr);
	if (msg == NULL)
		return 0;

	if (unlikely(msg_version(msg) != TIPC_VERSION))
		return 0;

	size = msg_size(msg);
	hdr_size = msg_hdr_sz(msg);
	min_hdr_size = msg_isdata(msg) ?
		min_data_hdr_size[msg_type(msg)] : INT_H_SIZE;

	if (unlikely((hdr_size < min_hdr_size) ||
		     (size < hdr_size) ||
		     (buf->len < size) ||
		     (size - hdr_size > TIPC_MAX_USER_MSG_SIZE)))
		return 0;

	return pskb_may_pull(buf, hdr_size);
}

void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *tb_ptr)
{
	read_lock_bh(&tipc_net_lock);
	while (head) {
		struct bearer *b_ptr = (struct bearer *)tb_ptr;
		struct tipc_node *n_ptr;
		struct link *l_ptr;
		struct sk_buff *crs;
		struct sk_buff *buf = head;
		struct tipc_msg *msg;
		u32 seq_no;
		u32 ackd;
		u32 released = 0;
		int type;

		head = head->next;

		/* Ensure message is well-formed */

		if (unlikely(!link_recv_buf_validate(buf)))
			goto cont;

		/* Ensure message data is a single contiguous unit */

		if (unlikely(buf_linearize(buf))) {
			goto cont;
		}

		/* Handle arrival of a non-unicast link message */

		msg = buf_msg(buf);

		if (unlikely(msg_non_seq(msg))) {
			if (msg_user(msg) ==  LINK_CONFIG)
				tipc_disc_recv_msg(buf, b_ptr);
			else
				tipc_bclink_recv_pkt(buf);
			continue;
		}

		if (unlikely(!msg_short(msg) &&
			     (msg_destnode(msg) != tipc_own_addr)))
			goto cont;

		/* Discard non-routeable messages destined for another node */

		if (unlikely(!msg_isdata(msg) &&
			     (msg_destnode(msg) != tipc_own_addr))) {
			if ((msg_user(msg) != CONN_MANAGER) &&
			    (msg_user(msg) != MSG_FRAGMENTER))
				goto cont;
		}

		/* Locate unicast link endpoint that should handle message */

		n_ptr = tipc_node_find(msg_prevnode(msg));
		if (unlikely(!n_ptr))
			g…
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