link.c

linux 内核源代码

/*
 * 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"


/*
 * 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_print(&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, TIPC_OK, INT_H_SIZE, l_ptr->addr);
	msg_set_size(msg, sizeof(l_ptr->proto_msg));
	msg_set_session(msg, tipc_random);
	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) {