net/tipc/net.c

Source file repositories/reference/linux-study-clean/net/tipc/net.c

File Facts

System
Linux kernel
Corpus path
net/tipc/net.c
Extension
.c
Size
10427 bytes
Lines
348
Domain
Networking Core
Bucket
Sockets, Protocols, Packet Path, And Network Policy
Inferred role
Networking Core: implementation source
Status
source implementation candidate

Why This File Exists

Networking stack implementation surface: socket APIs, protocol dispatch, packet flow, routing, filtering, and network namespaces.

Dependency Surface

Detected Declarations

Annotated Snippet

#include "core.h"
#include "net.h"
#include "name_distr.h"
#include "subscr.h"
#include "socket.h"
#include "node.h"
#include "bcast.h"
#include "link.h"
#include "netlink.h"
#include "monitor.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., when 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 tipc_net_finalize(struct net *net, u32 addr);

int tipc_net_init(struct net *net, u8 *node_id, u32 addr)
{
	if (tipc_own_id(net)) {
		pr_info("Cannot configure node identity twice\n");
		return -1;
	}
	pr_info("Started in network mode\n");

	if (node_id)
		tipc_set_node_id(net, node_id);
	if (addr)
		tipc_net_finalize(net, addr);
	return 0;
}

static void tipc_net_finalize(struct net *net, u32 addr)

Annotation

Implementation Notes