/*
* net/tipc/net.c: TIPC network routing code
*
* Copyright (c) 1995-2006, Ericsson AB
* 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 "core.h"
#include "net.h"
#include "name_distr.h"
#include "subscr.h"
#include "port.h"
#include "socket.h"
#include "node.h"
#include "config.h"
/*
* The TIPC locking policy is designed to ensure a very fine locking
* granularity, permitting complete parallel access to individual
* port and node/link instances. The code consists of four major
* locking domains, each protected with their own disjunct set of locks.
*
* 1: The bearer level.
* RTNL lock is used to serialize the process of configuring bearer
* on update side, and RCU lock is applied on read side to make
* bearer instance valid on both paths of message transmission and
* reception.
*
* 2: The node and link level.
* All node instances are saved into two tipc_node_list and node_htable
* lists. The two lists are protected by node_list_lock on write side,
* and they are guarded with RCU lock on read side. Especially node
* instance is destroyed only when TIPC module is removed, and we can
* confirm that there has no any user who is accessing the node at the
* moment. Therefore, Except for iterating the two lists within RCU
* protection, it's no needed to hold RCU that we access node instance
* in other places.
*
* In addition, all members in node structure including link instances
* are protected by node spin lock.
*
* 3: The transport level of the protocol.
* This consists of the structures port, (and its user level
* representations, such as user_port and tipc_sock), reference and
* tipc_user (port.c, reg.c, socket.c).
*
* This layer has four different locks:
* - The tipc_port spin_lock. This is protecting each port instance
* from parallel data access and removal. Since we can not place
* this lock in the port itself, it has been placed in the
* corresponding reference table entry, which has the same life
* cycle as the module. This entry is difficult to access from
* outside the TIPC core, however, so a pointer to the lock has
* been added in the port instance, -to be used for unlocking
* only.
* - A read/write lock to protect the reference table itself (teg.c).
* (Nobody is using read-only access to this, so it can just as
* well be changed to a spin_lock)
* - A spin lock to protect the registry of kernel/driver users (reg.c)
* - A global spin_lock (tipc_port_lock), which only task is to ensure
* consistency where more than one port is involved in an operation,
* i.e., whe a port is part of a linked list of ports.
* There are two such lists; 'port_list', which is used for management,
* and 'wait_list', which is used to queue ports during congestion.
*
* 4: The name table (name_table.c, name_distr.c, subscription.c)
* - There is one big read/write-lock (tipc_nametbl_lock) protecting the
* overall name table structure. Nothing must be added/removed to
* this structure without holding write access to it.
* - There is one local spin_lock per sub_sequence, which can be seen
* as a sub-domain to the tipc_nametbl_lock domain. It is used only
* for translation operations, and is needed because a translation
* steps the root of the 'publication' linked list between each lookup.
* This is always used within the scope of a tipc_nametbl_lock(read).
* - A local spin_lock protecting the queue of subscriber events.
*/
static void net_route_named_msg(struct sk_buff *buf)
{
struct tipc_msg *msg = buf_msg(buf);
u32 dnode;
u32 dport;
if (!msg_named(msg)) {
kfree_skb(buf);
return;
}
dnode = addr_domain(msg_lookup_scope(msg));
dport = tipc_nametbl_translate(msg_nametype(msg), msg_nameinst(msg), &dnode);
if (dport) {
msg_set_destnode(msg, dnode);
msg_set_destport(msg, dport);
tipc_net_route_msg(buf);
return;
}
tipc_reject_msg(buf, TIPC_ERR_NO_NAME);
}
void tipc_net_route_msg(struct sk_buff *buf)
{
struct tipc_msg *msg;
u32 dnode;
if (!buf)
return;
msg = buf_msg(buf);
/* Handle message for this node */
dnode = msg_short(msg) ? tipc_own_addr : msg_destnode(msg);
if (tipc_in_scope(dnode, tipc_own_addr)) {
if (msg_isdata(msg)) {
if (msg_mcast(msg))
tipc_port_mcast_rcv(buf, NULL);
else if (msg_destport(msg))
tipc_sk_rcv(buf);
else
net_route_named_msg(buf);
return;
}
switch (msg_user(msg)) {
case NAME_DISTRIBUTOR:
tipc_named_rcv(buf);
break;
case CONN_MANAGER:
tipc_port_proto_rcv(buf);
break;
default:
kfree_skb(buf);
}
return;
}
/* Handle message for another node */
skb_trim(buf, msg_size(msg));
tipc_link_xmit(buf, dnode, msg_link_selector(msg));
}
int tipc_net_start(u32 addr)
{
char addr_string[16];
int res;
tipc_own_addr = addr;
tipc_named_reinit();
tipc_port_reinit();
res = tipc_bclink_init();
if (res)
return res;
tipc_nametbl_publish(TIPC_CFG_SRV, tipc_own_addr, tipc_own_addr,
TIPC_ZONE_SCOPE, 0, tipc_own_addr);
pr_info("Started in network mode\n");
pr_info("Own node address %s, network identity %u\n",
tipc_addr_string_fill(addr_string, tipc_own_addr), tipc_net_id);
return 0;
}
void tipc_net_stop(void)
{
if (!tipc_own_addr)
return;
tipc_nametbl_withdraw(TIPC_CFG_SRV, tipc_own_addr, 0, tipc_own_addr);
rtnl_lock();
tipc_bearer_stop();
tipc_bclink_stop();
tipc_node_stop();
rtnl_unlock();
pr_info("Left network mode\n");
}
