linux/net/tipc/net.c
Jon Paul Maloy 5fd9fd6351 tipc: create broadcast transmission link at namespace init
The broadcast transmission link is currently instantiated when the
network subsystem is started, i.e., on order from user space via netlink.

This forces the broadcast transmission code to do unnecessary tests for
the existence of the transmission link, as well in single mode node as
in network mode.

In this commit, we do instead create the link during initialization of
the name space, and remove it when it is stopped. The fact that the
transmission link now has a guaranteed longer life cycle than any of its
potential clients paves the way for further code simplifcations
and optimizations.

Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-10-24 06:56:27 -07:00

252 lines
8.2 KiB
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;
}