alistair23-linux/net/tipc/node.h
Jon Maloy 25b0b9c4e8 tipc: handle collisions of 32-bit node address hash values
When a 32-bit node address is generated from a 128-bit identifier,
there is a risk of collisions which must be discovered and handled.

We do this as follows:
- We don't apply the generated address immediately to the node, but do
  instead initiate a 1 sec trial period to allow other cluster members
  to discover and handle such collisions.

- During the trial period the node periodically sends out a new type
  of message, DSC_TRIAL_MSG, using broadcast or emulated broadcast,
  to all the other nodes in the cluster.

- When a node is receiving such a message, it must check that the
  presented 32-bit identifier either is unused, or was used by the very
  same peer in a previous session. In both cases it accepts the request
  by not responding to it.

- If it finds that the same node has been up before using a different
  address, it responds with a DSC_TRIAL_FAIL_MSG containing that
  address.

- If it finds that the address has already been taken by some other
  node, it generates a new, unused address and returns it to the
  requester.

- During the trial period the requesting node must always be prepared
  to accept a failure message, i.e., a message where a peer suggests a
  different (or equal)  address to the one tried. In those cases it
  must apply the suggested value as trial address and restart the trial
  period.

This algorithm ensures that in the vast majority of cases a node will
have the same address before and after a reboot. If a legacy user
configures the address explicitly, there will be no trial period and
messages, so this protocol addition is completely backwards compatible.

Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-03-23 13:12:18 -04:00

99 lines
4.4 KiB
C

/*
* net/tipc/node.h: Include file for TIPC node management routines
*
* Copyright (c) 2000-2006, 2014-2016, Ericsson AB
* Copyright (c) 2005, 2010-2014, 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.
*/
#ifndef _TIPC_NODE_H
#define _TIPC_NODE_H
#include "addr.h"
#include "net.h"
#include "bearer.h"
#include "msg.h"
/* Optional capabilities supported by this code version
*/
enum {
TIPC_BCAST_SYNCH = (1 << 1),
TIPC_BCAST_STATE_NACK = (1 << 2),
TIPC_BLOCK_FLOWCTL = (1 << 3),
TIPC_BCAST_RCAST = (1 << 4),
TIPC_NODE_ID128 = (1 << 5)
};
#define TIPC_NODE_CAPABILITIES (TIPC_BCAST_SYNCH | \
TIPC_BCAST_STATE_NACK | \
TIPC_BCAST_RCAST | \
TIPC_BLOCK_FLOWCTL | \
TIPC_NODE_ID128)
#define INVALID_BEARER_ID -1
void tipc_node_stop(struct net *net);
u32 tipc_node_try_addr(struct net *net, u8 *id, u32 addr);
void tipc_node_check_dest(struct net *net, u32 onode, u8 *peer_id128,
struct tipc_bearer *bearer,
u16 capabilities, u32 signature,
struct tipc_media_addr *maddr,
bool *respond, bool *dupl_addr);
void tipc_node_delete_links(struct net *net, int bearer_id);
void tipc_node_apply_tolerance(struct net *net, struct tipc_bearer *b);
int tipc_node_get_linkname(struct net *net, u32 bearer_id, u32 node,
char *linkname, size_t len);
int tipc_node_xmit(struct net *net, struct sk_buff_head *list, u32 dnode,
int selector);
int tipc_node_distr_xmit(struct net *net, struct sk_buff_head *list);
int tipc_node_xmit_skb(struct net *net, struct sk_buff *skb, u32 dest,
u32 selector);
void tipc_node_subscribe(struct net *net, struct list_head *subscr, u32 addr);
void tipc_node_unsubscribe(struct net *net, struct list_head *subscr, u32 addr);
void tipc_node_broadcast(struct net *net, struct sk_buff *skb);
int tipc_node_add_conn(struct net *net, u32 dnode, u32 port, u32 peer_port);
void tipc_node_remove_conn(struct net *net, u32 dnode, u32 port);
int tipc_node_get_mtu(struct net *net, u32 addr, u32 sel);
bool tipc_node_is_up(struct net *net, u32 addr);
u16 tipc_node_get_capabilities(struct net *net, u32 addr);
int tipc_nl_node_dump(struct sk_buff *skb, struct netlink_callback *cb);
int tipc_nl_node_dump_link(struct sk_buff *skb, struct netlink_callback *cb);
int tipc_nl_node_reset_link_stats(struct sk_buff *skb, struct genl_info *info);
int tipc_nl_node_get_link(struct sk_buff *skb, struct genl_info *info);
int tipc_nl_node_set_link(struct sk_buff *skb, struct genl_info *info);
int tipc_nl_peer_rm(struct sk_buff *skb, struct genl_info *info);
int tipc_nl_node_set_monitor(struct sk_buff *skb, struct genl_info *info);
int tipc_nl_node_get_monitor(struct sk_buff *skb, struct genl_info *info);
int tipc_nl_node_dump_monitor(struct sk_buff *skb, struct netlink_callback *cb);
int tipc_nl_node_dump_monitor_peer(struct sk_buff *skb,
struct netlink_callback *cb);
#endif