- 根目录:
- net
- tipc
- net.c
/*
* net/tipc/net.c: TIPC network routing code
*
* Copyright (c) 1995-2006, 2014, 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 "socket.h"
#include "node.h"
#include "bcast.h"
static const struct nla_policy tipc_nl_net_policy[TIPC_NLA_NET_MAX + 1] = {
[TIPC_NLA_NET_UNSPEC] = { .type = NLA_UNSPEC },
[TIPC_NLA_NET_ID] = { .type = NLA_U32 }
};
/*
* 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.
*/
int tipc_net_start(struct net *net, u32 addr)
{
struct tipc_net *tn = net_generic(net, tipc_net_id);
char addr_string[16];
tn->own_addr = addr;
tipc_named_reinit(net);
tipc_sk_reinit(net);
tipc_bcast_reinit(net);
tipc_nametbl_publish(net, TIPC_CFG_SRV, tn->own_addr, tn->own_addr,
TIPC_ZONE_SCOPE, 0, tn->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, tn->own_addr),
tn->net_id);
return 0;
}
void tipc_net_stop(struct net *net)
{
struct tipc_net *tn = net_generic(net, tipc_net_id);
if (!tn->own_addr)
return;
tipc_nametbl_withdraw(net, TIPC_CFG_SRV, tn->own_addr, 0,
tn->own_addr);
rtnl_lock();
tipc_bearer_stop(net);
tipc_node_stop(net);
rtnl_unlock();
pr_info("Left network mode\n");
}
static int __tipc_nl_add_net(struct net *net, struct tipc_nl_msg *msg)
{
struct tipc_net *tn = net_generic(net, tipc_net_id);
void *hdr;
struct nlattr *attrs;
hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
NLM_F_MULTI, TIPC_NL_NET_GET);
if (!hdr)
return -EMSGSIZE;
attrs = nla_nest_start(msg->skb, TIPC_NLA_NET);
if (!attrs)
goto msg_full;
if (nla_put_u32(msg->skb, TIPC_NLA_NET_ID, tn->net_id))
goto attr_msg_full;
nla_nest_end(msg->skb, attrs);
genlmsg_end(msg->skb, hdr);
return 0;
attr_msg_full:
nla_nest_cancel(msg->skb, attrs);
msg_full:
genlmsg_cancel(msg->skb, hdr);
return -EMSGSIZE;
}
int tipc_nl_net_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
struct net *net = sock_net(skb->sk);
int err;
int done = cb->args[0];
struct tipc_nl_msg msg;
if (done)
return 0;
msg.skb = skb;
msg.portid = NETLINK_CB(cb->skb).portid;
msg.seq = cb->nlh->nlmsg_seq;
err = __tipc_nl_add_net(net, &msg);
if (err)
goto out;
done = 1;
out:
cb->args[0] = done;
return skb->len;
}
int tipc_nl_net_set(struct sk_buff *skb, struct genl_info *info)
{
struct net *net = sock_net(skb->sk);
struct tipc_net *tn = net_generic(net, tipc_net_id);
struct nlattr *attrs[TIPC_NLA_NET_MAX + 1];
int err;
if (!info->attrs[TIPC_NLA_NET])
return -EINVAL;
err = nla_parse_nested(attrs, TIPC_NLA_NET_MAX,
info->attrs[TIPC_NLA_NET],
tipc_nl_net_policy);
if (err)
return err;
if (attrs[TIPC_NLA_NET_ID]) {
u32 val;
/* Can't change net id once TIPC has joined a network */
if (tn->own_addr)
return -EPERM;
val = nla_get_u32(attrs[TIPC_NLA_NET_ID]);
if (val < 1 || val > 9999)
return -EINVAL;
tn->net_id = val;
}
if (attrs[TIPC_NLA_NET_ADDR]) {
u32 addr;
/* Can't change net addr once TIPC has joined a network */
if (tn->own_addr)
return -EPERM;
addr = nla_get_u32(attrs[TIPC_NLA_NET_ADDR]);
if (!tipc_addr_node_valid(addr))
return -EINVAL;
rtnl_lock();
tipc_net_start(net, addr);
rtnl_unlock();
}
return 0;
}