206 lines
7.6 KiB
C
206 lines
7.6 KiB
C
/*
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* net/tipc/net.c: TIPC network routing code
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*
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* Copyright (c) 1995-2006, Ericsson AB
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* Copyright (c) 2005, 2010-2011, Wind River Systems
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the names of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* Alternatively, this software may be distributed under the terms of the
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* GNU General Public License ("GPL") version 2 as published by the Free
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* Software Foundation.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "core.h"
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#include "net.h"
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#include "name_distr.h"
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#include "subscr.h"
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#include "port.h"
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#include "node.h"
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#include "config.h"
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/*
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* The TIPC locking policy is designed to ensure a very fine locking
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* granularity, permitting complete parallel access to individual
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* port and node/link instances. The code consists of three major
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* locking domains, each protected with their own disjunct set of locks.
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*
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* 1: The routing hierarchy.
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* Comprises the structures 'zone', 'cluster', 'node', 'link'
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* and 'bearer'. The whole hierarchy is protected by a big
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* read/write lock, tipc_net_lock, to enssure that nothing is added
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* or removed while code is accessing any of these structures.
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* This layer must not be called from the two others while they
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* hold any of their own locks.
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* Neither must it itself do any upcalls to the other two before
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* it has released tipc_net_lock and other protective locks.
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*
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* Within the tipc_net_lock domain there are two sub-domains;'node' and
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* 'bearer', where local write operations are permitted,
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* provided that those are protected by individual spin_locks
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* per instance. Code holding tipc_net_lock(read) and a node spin_lock
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* is permitted to poke around in both the node itself and its
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* subordinate links. I.e, it can update link counters and queues,
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* change link state, send protocol messages, and alter the
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* "active_links" array in the node; but it can _not_ remove a link
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* or a node from the overall structure.
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* Correspondingly, individual bearers may change status within a
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* tipc_net_lock(read), protected by an individual spin_lock ber bearer
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* instance, but it needs tipc_net_lock(write) to remove/add any bearers.
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*
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*
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* 2: The transport level of the protocol.
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* This consists of the structures port, (and its user level
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* representations, such as user_port and tipc_sock), reference and
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* tipc_user (port.c, reg.c, socket.c).
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*
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* This layer has four different locks:
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* - The tipc_port spin_lock. This is protecting each port instance
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* from parallel data access and removal. Since we can not place
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* this lock in the port itself, it has been placed in the
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* corresponding reference table entry, which has the same life
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* cycle as the module. This entry is difficult to access from
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* outside the TIPC core, however, so a pointer to the lock has
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* been added in the port instance, -to be used for unlocking
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* only.
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* - A read/write lock to protect the reference table itself (teg.c).
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* (Nobody is using read-only access to this, so it can just as
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* well be changed to a spin_lock)
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* - A spin lock to protect the registry of kernel/driver users (reg.c)
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* - A global spin_lock (tipc_port_lock), which only task is to ensure
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* consistency where more than one port is involved in an operation,
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* i.e., whe a port is part of a linked list of ports.
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* There are two such lists; 'port_list', which is used for management,
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* and 'wait_list', which is used to queue ports during congestion.
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*
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* 3: The name table (name_table.c, name_distr.c, subscription.c)
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* - There is one big read/write-lock (tipc_nametbl_lock) protecting the
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* overall name table structure. Nothing must be added/removed to
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* this structure without holding write access to it.
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* - There is one local spin_lock per sub_sequence, which can be seen
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* as a sub-domain to the tipc_nametbl_lock domain. It is used only
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* for translation operations, and is needed because a translation
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* steps the root of the 'publication' linked list between each lookup.
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* This is always used within the scope of a tipc_nametbl_lock(read).
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* - A local spin_lock protecting the queue of subscriber events.
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*/
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DEFINE_RWLOCK(tipc_net_lock);
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static void net_route_named_msg(struct sk_buff *buf)
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{
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struct tipc_msg *msg = buf_msg(buf);
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u32 dnode;
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u32 dport;
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if (!msg_named(msg)) {
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kfree_skb(buf);
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return;
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}
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dnode = addr_domain(msg_lookup_scope(msg));
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dport = tipc_nametbl_translate(msg_nametype(msg), msg_nameinst(msg), &dnode);
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if (dport) {
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msg_set_destnode(msg, dnode);
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msg_set_destport(msg, dport);
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tipc_net_route_msg(buf);
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return;
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}
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tipc_reject_msg(buf, TIPC_ERR_NO_NAME);
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}
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void tipc_net_route_msg(struct sk_buff *buf)
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{
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struct tipc_msg *msg;
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u32 dnode;
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if (!buf)
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return;
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msg = buf_msg(buf);
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/* Handle message for this node */
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dnode = msg_short(msg) ? tipc_own_addr : msg_destnode(msg);
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if (tipc_in_scope(dnode, tipc_own_addr)) {
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if (msg_isdata(msg)) {
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if (msg_mcast(msg))
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tipc_port_recv_mcast(buf, NULL);
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else if (msg_destport(msg))
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tipc_port_recv_msg(buf);
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else
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net_route_named_msg(buf);
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return;
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}
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switch (msg_user(msg)) {
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case NAME_DISTRIBUTOR:
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tipc_named_recv(buf);
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break;
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case CONN_MANAGER:
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tipc_port_recv_proto_msg(buf);
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break;
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default:
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kfree_skb(buf);
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}
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return;
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}
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/* Handle message for another node */
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skb_trim(buf, msg_size(msg));
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tipc_link_send(buf, dnode, msg_link_selector(msg));
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}
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void tipc_net_start(u32 addr)
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{
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char addr_string[16];
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write_lock_bh(&tipc_net_lock);
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tipc_own_addr = addr;
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tipc_named_reinit();
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tipc_port_reinit();
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tipc_bclink_init();
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write_unlock_bh(&tipc_net_lock);
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tipc_cfg_reinit();
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pr_info("Started in network mode\n");
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pr_info("Own node address %s, network identity %u\n",
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tipc_addr_string_fill(addr_string, tipc_own_addr), tipc_net_id);
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}
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void tipc_net_stop(void)
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{
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struct tipc_node *node, *t_node;
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if (!tipc_own_addr)
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return;
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write_lock_bh(&tipc_net_lock);
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tipc_bearer_stop();
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tipc_bclink_stop();
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list_for_each_entry_safe(node, t_node, &tipc_node_list, list)
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tipc_node_delete(node);
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write_unlock_bh(&tipc_net_lock);
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pr_info("Left network mode\n");
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}
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