android_kernel_xiaomi_sm8350/net/tipc/socket.c
Allan Stephens 05646c9110 [TIPC]: Optimize stream send routine to avoid fragmentation
This patch enhances TIPC's stream socket send routine so that
it avoids transmitting data in chunks that require fragmentation
and reassembly, thereby improving performance at both the
sending and receiving ends of the connection.

The "maximum packet size" hint that records MTU info allows
the socket to decide how big a chunk it should send; in the
event that the hint has become stale, fragmentation may still
occur, but the data will be passed correctly and the hint will
be updated in time for the following send.  Note: The 66060 byte
pseudo-MTU used for intra-node connections requires the send
routine to perform an additional check to ensure it does not
exceed TIPC"s limit of 66000 bytes of user data per chunk.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Jon Paul Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-07-10 22:06:12 -07:00

1730 lines
41 KiB
C

/*
* net/tipc/socket.c: TIPC socket API
*
* Copyright (c) 2001-2007, Ericsson AB
* Copyright (c) 2004-2007, 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 <linux/module.h>
#include <linux/types.h>
#include <linux/net.h>
#include <linux/socket.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/poll.h>
#include <linux/fcntl.h>
#include <asm/semaphore.h>
#include <asm/string.h>
#include <asm/atomic.h>
#include <net/sock.h>
#include <linux/tipc.h>
#include <linux/tipc_config.h>
#include <net/tipc/tipc_msg.h>
#include <net/tipc/tipc_port.h>
#include "core.h"
#define SS_LISTENING -1 /* socket is listening */
#define SS_READY -2 /* socket is connectionless */
#define OVERLOAD_LIMIT_BASE 5000
struct tipc_sock {
struct sock sk;
struct tipc_port *p;
struct semaphore sem;
};
#define tipc_sk(sk) ((struct tipc_sock*)sk)
static u32 dispatch(struct tipc_port *tport, struct sk_buff *buf);
static void wakeupdispatch(struct tipc_port *tport);
static struct proto_ops packet_ops;
static struct proto_ops stream_ops;
static struct proto_ops msg_ops;
static struct proto tipc_proto;
static int sockets_enabled = 0;
static atomic_t tipc_queue_size = ATOMIC_INIT(0);
/*
* sock_lock(): Lock a port/socket pair. lock_sock() can
* not be used here, since the same lock must protect ports
* with non-socket interfaces.
* See net.c for description of locking policy.
*/
static void sock_lock(struct tipc_sock* tsock)
{
spin_lock_bh(tsock->p->lock);
}
/*
* sock_unlock(): Unlock a port/socket pair
*/
static void sock_unlock(struct tipc_sock* tsock)
{
spin_unlock_bh(tsock->p->lock);
}
/**
* pollmask - determine the current set of poll() events for a socket
* @sock: socket structure
*
* TIPC sets the returned events as follows:
* a) POLLRDNORM and POLLIN are set if the socket's receive queue is non-empty
* or if a connection-oriented socket is does not have an active connection
* (i.e. a read operation will not block).
* b) POLLOUT is set except when a socket's connection has been terminated
* (i.e. a write operation will not block).
* c) POLLHUP is set when a socket's connection has been terminated.
*
* IMPORTANT: The fact that a read or write operation will not block does NOT
* imply that the operation will succeed!
*
* Returns pollmask value
*/
static u32 pollmask(struct socket *sock)
{
u32 mask;
if ((skb_queue_len(&sock->sk->sk_receive_queue) != 0) ||
(sock->state == SS_UNCONNECTED) ||
(sock->state == SS_DISCONNECTING))
mask = (POLLRDNORM | POLLIN);
else
mask = 0;
if (sock->state == SS_DISCONNECTING)
mask |= POLLHUP;
else
mask |= POLLOUT;
return mask;
}
/**
* advance_queue - discard first buffer in queue
* @tsock: TIPC socket
*/
static void advance_queue(struct tipc_sock *tsock)
{
sock_lock(tsock);
buf_discard(skb_dequeue(&tsock->sk.sk_receive_queue));
sock_unlock(tsock);
atomic_dec(&tipc_queue_size);
}
/**
* tipc_create - create a TIPC socket
* @sock: pre-allocated socket structure
* @protocol: protocol indicator (must be 0)
*
* This routine creates and attaches a 'struct sock' to the 'struct socket',
* then create and attaches a TIPC port to the 'struct sock' part.
*
* Returns 0 on success, errno otherwise
*/
static int tipc_create(struct socket *sock, int protocol)
{
struct tipc_sock *tsock;
struct tipc_port *port;
struct sock *sk;
u32 ref;
if (unlikely(protocol != 0))
return -EPROTONOSUPPORT;
ref = tipc_createport_raw(NULL, &dispatch, &wakeupdispatch, TIPC_LOW_IMPORTANCE);
if (unlikely(!ref))
return -ENOMEM;
sock->state = SS_UNCONNECTED;
switch (sock->type) {
case SOCK_STREAM:
sock->ops = &stream_ops;
break;
case SOCK_SEQPACKET:
sock->ops = &packet_ops;
break;
case SOCK_DGRAM:
tipc_set_portunreliable(ref, 1);
/* fall through */
case SOCK_RDM:
tipc_set_portunreturnable(ref, 1);
sock->ops = &msg_ops;
sock->state = SS_READY;
break;
default:
tipc_deleteport(ref);
return -EPROTOTYPE;
}
sk = sk_alloc(AF_TIPC, GFP_KERNEL, &tipc_proto, 1);
if (!sk) {
tipc_deleteport(ref);
return -ENOMEM;
}
sock_init_data(sock, sk);
init_waitqueue_head(sk->sk_sleep);
sk->sk_rcvtimeo = 8 * HZ; /* default connect timeout = 8s */
tsock = tipc_sk(sk);
port = tipc_get_port(ref);
tsock->p = port;
port->usr_handle = tsock;
init_MUTEX(&tsock->sem);
dbg("sock_create: %x\n",tsock);
atomic_inc(&tipc_user_count);
return 0;
}
/**
* release - destroy a TIPC socket
* @sock: socket to destroy
*
* This routine cleans up any messages that are still queued on the socket.
* For DGRAM and RDM socket types, all queued messages are rejected.
* For SEQPACKET and STREAM socket types, the first message is rejected
* and any others are discarded. (If the first message on a STREAM socket
* is partially-read, it is discarded and the next one is rejected instead.)
*
* NOTE: Rejected messages are not necessarily returned to the sender! They
* are returned or discarded according to the "destination droppable" setting
* specified for the message by the sender.
*
* Returns 0 on success, errno otherwise
*/
static int release(struct socket *sock)
{
struct tipc_sock *tsock = tipc_sk(sock->sk);
struct sock *sk = sock->sk;
int res = TIPC_OK;
struct sk_buff *buf;
dbg("sock_delete: %x\n",tsock);
if (!tsock)
return 0;
down_interruptible(&tsock->sem);
if (!sock->sk) {
up(&tsock->sem);
return 0;
}
/* Reject unreceived messages, unless no longer connected */
while (sock->state != SS_DISCONNECTING) {
sock_lock(tsock);
buf = skb_dequeue(&sk->sk_receive_queue);
if (!buf)
tsock->p->usr_handle = NULL;
sock_unlock(tsock);
if (!buf)
break;
if (TIPC_SKB_CB(buf)->handle != msg_data(buf_msg(buf)))
buf_discard(buf);
else
tipc_reject_msg(buf, TIPC_ERR_NO_PORT);
atomic_dec(&tipc_queue_size);
}
/* Delete TIPC port */
res = tipc_deleteport(tsock->p->ref);
sock->sk = NULL;
/* Discard any remaining messages */
while ((buf = skb_dequeue(&sk->sk_receive_queue))) {
buf_discard(buf);
atomic_dec(&tipc_queue_size);
}
up(&tsock->sem);
sock_put(sk);
atomic_dec(&tipc_user_count);
return res;
}
/**
* bind - associate or disassocate TIPC name(s) with a socket
* @sock: socket structure
* @uaddr: socket address describing name(s) and desired operation
* @uaddr_len: size of socket address data structure
*
* Name and name sequence binding is indicated using a positive scope value;
* a negative scope value unbinds the specified name. Specifying no name
* (i.e. a socket address length of 0) unbinds all names from the socket.
*
* Returns 0 on success, errno otherwise
*/
static int bind(struct socket *sock, struct sockaddr *uaddr, int uaddr_len)
{
struct tipc_sock *tsock = tipc_sk(sock->sk);
struct sockaddr_tipc *addr = (struct sockaddr_tipc *)uaddr;
int res;
if (down_interruptible(&tsock->sem))
return -ERESTARTSYS;
if (unlikely(!uaddr_len)) {
res = tipc_withdraw(tsock->p->ref, 0, NULL);
goto exit;
}
if (uaddr_len < sizeof(struct sockaddr_tipc)) {
res = -EINVAL;
goto exit;
}
if (addr->family != AF_TIPC) {
res = -EAFNOSUPPORT;
goto exit;
}
if (addr->addrtype == TIPC_ADDR_NAME)
addr->addr.nameseq.upper = addr->addr.nameseq.lower;
else if (addr->addrtype != TIPC_ADDR_NAMESEQ) {
res = -EAFNOSUPPORT;
goto exit;
}
if (addr->scope > 0)
res = tipc_publish(tsock->p->ref, addr->scope,
&addr->addr.nameseq);
else
res = tipc_withdraw(tsock->p->ref, -addr->scope,
&addr->addr.nameseq);
exit:
up(&tsock->sem);
return res;
}
/**
* get_name - get port ID of socket or peer socket
* @sock: socket structure
* @uaddr: area for returned socket address
* @uaddr_len: area for returned length of socket address
* @peer: 0 to obtain socket name, 1 to obtain peer socket name
*
* Returns 0 on success, errno otherwise
*/
static int get_name(struct socket *sock, struct sockaddr *uaddr,
int *uaddr_len, int peer)
{
struct tipc_sock *tsock = tipc_sk(sock->sk);
struct sockaddr_tipc *addr = (struct sockaddr_tipc *)uaddr;
u32 res;
if (down_interruptible(&tsock->sem))
return -ERESTARTSYS;
*uaddr_len = sizeof(*addr);
addr->addrtype = TIPC_ADDR_ID;
addr->family = AF_TIPC;
addr->scope = 0;
if (peer)
res = tipc_peer(tsock->p->ref, &addr->addr.id);
else
res = tipc_ownidentity(tsock->p->ref, &addr->addr.id);
addr->addr.name.domain = 0;
up(&tsock->sem);
return res;
}
/**
* poll - read and possibly block on pollmask
* @file: file structure associated with the socket
* @sock: socket for which to calculate the poll bits
* @wait: ???
*
* Returns the pollmask
*/
static unsigned int poll(struct file *file, struct socket *sock,
poll_table *wait)
{
poll_wait(file, sock->sk->sk_sleep, wait);
/* NEED LOCK HERE? */
return pollmask(sock);
}
/**
* dest_name_check - verify user is permitted to send to specified port name
* @dest: destination address
* @m: descriptor for message to be sent
*
* Prevents restricted configuration commands from being issued by
* unauthorized users.
*
* Returns 0 if permission is granted, otherwise errno
*/
static int dest_name_check(struct sockaddr_tipc *dest, struct msghdr *m)
{
struct tipc_cfg_msg_hdr hdr;
if (likely(dest->addr.name.name.type >= TIPC_RESERVED_TYPES))
return 0;
if (likely(dest->addr.name.name.type == TIPC_TOP_SRV))
return 0;
if (likely(dest->addr.name.name.type != TIPC_CFG_SRV))
return -EACCES;
if (copy_from_user(&hdr, m->msg_iov[0].iov_base, sizeof(hdr)))
return -EFAULT;
if ((ntohs(hdr.tcm_type) & 0xC000) && (!capable(CAP_NET_ADMIN)))
return -EACCES;
return 0;
}
/**
* send_msg - send message in connectionless manner
* @iocb: (unused)
* @sock: socket structure
* @m: message to send
* @total_len: length of message
*
* Message must have an destination specified explicitly.
* Used for SOCK_RDM and SOCK_DGRAM messages,
* and for 'SYN' messages on SOCK_SEQPACKET and SOCK_STREAM connections.
* (Note: 'SYN+' is prohibited on SOCK_STREAM.)
*
* Returns the number of bytes sent on success, or errno otherwise
*/
static int send_msg(struct kiocb *iocb, struct socket *sock,
struct msghdr *m, size_t total_len)
{
struct tipc_sock *tsock = tipc_sk(sock->sk);
struct sockaddr_tipc *dest = (struct sockaddr_tipc *)m->msg_name;
struct sk_buff *buf;
int needs_conn;
int res = -EINVAL;
if (unlikely(!dest))
return -EDESTADDRREQ;
if (unlikely((m->msg_namelen < sizeof(*dest)) ||
(dest->family != AF_TIPC)))
return -EINVAL;
needs_conn = (sock->state != SS_READY);
if (unlikely(needs_conn)) {
if (sock->state == SS_LISTENING)
return -EPIPE;
if (sock->state != SS_UNCONNECTED)
return -EISCONN;
if ((tsock->p->published) ||
((sock->type == SOCK_STREAM) && (total_len != 0)))
return -EOPNOTSUPP;
if (dest->addrtype == TIPC_ADDR_NAME) {
tsock->p->conn_type = dest->addr.name.name.type;
tsock->p->conn_instance = dest->addr.name.name.instance;
}
}
if (down_interruptible(&tsock->sem))
return -ERESTARTSYS;
if (needs_conn) {
/* Abort any pending connection attempts (very unlikely) */
while ((buf = skb_dequeue(&sock->sk->sk_receive_queue))) {
tipc_reject_msg(buf, TIPC_ERR_NO_PORT);
atomic_dec(&tipc_queue_size);
}
sock->state = SS_CONNECTING;
}
do {
if (dest->addrtype == TIPC_ADDR_NAME) {
if ((res = dest_name_check(dest, m)))
goto exit;
res = tipc_send2name(tsock->p->ref,
&dest->addr.name.name,
dest->addr.name.domain,
m->msg_iovlen,
m->msg_iov);
}
else if (dest->addrtype == TIPC_ADDR_ID) {
res = tipc_send2port(tsock->p->ref,
&dest->addr.id,
m->msg_iovlen,
m->msg_iov);
}
else if (dest->addrtype == TIPC_ADDR_MCAST) {
if (needs_conn) {
res = -EOPNOTSUPP;
goto exit;
}
if ((res = dest_name_check(dest, m)))
goto exit;
res = tipc_multicast(tsock->p->ref,
&dest->addr.nameseq,
0,
m->msg_iovlen,
m->msg_iov);
}
if (likely(res != -ELINKCONG)) {
exit:
up(&tsock->sem);
return res;
}
if (m->msg_flags & MSG_DONTWAIT) {
res = -EWOULDBLOCK;
goto exit;
}
if (wait_event_interruptible(*sock->sk->sk_sleep,
!tsock->p->congested)) {
res = -ERESTARTSYS;
goto exit;
}
} while (1);
}
/**
* send_packet - send a connection-oriented message
* @iocb: (unused)
* @sock: socket structure
* @m: message to send
* @total_len: length of message
*
* Used for SOCK_SEQPACKET messages and SOCK_STREAM data.
*
* Returns the number of bytes sent on success, or errno otherwise
*/
static int send_packet(struct kiocb *iocb, struct socket *sock,
struct msghdr *m, size_t total_len)
{
struct tipc_sock *tsock = tipc_sk(sock->sk);
struct sockaddr_tipc *dest = (struct sockaddr_tipc *)m->msg_name;
int res;
/* Handle implied connection establishment */
if (unlikely(dest))
return send_msg(iocb, sock, m, total_len);
if (down_interruptible(&tsock->sem)) {
return -ERESTARTSYS;
}
do {
if (unlikely(sock->state != SS_CONNECTED)) {
if (sock->state == SS_DISCONNECTING)
res = -EPIPE;
else
res = -ENOTCONN;
goto exit;
}
res = tipc_send(tsock->p->ref, m->msg_iovlen, m->msg_iov);
if (likely(res != -ELINKCONG)) {
exit:
up(&tsock->sem);
return res;
}
if (m->msg_flags & MSG_DONTWAIT) {
res = -EWOULDBLOCK;
goto exit;
}
if (wait_event_interruptible(*sock->sk->sk_sleep,
!tsock->p->congested)) {
res = -ERESTARTSYS;
goto exit;
}
} while (1);
}
/**
* send_stream - send stream-oriented data
* @iocb: (unused)
* @sock: socket structure
* @m: data to send
* @total_len: total length of data to be sent
*
* Used for SOCK_STREAM data.
*
* Returns the number of bytes sent on success (or partial success),
* or errno if no data sent
*/
static int send_stream(struct kiocb *iocb, struct socket *sock,
struct msghdr *m, size_t total_len)
{
struct tipc_port *tport;
struct msghdr my_msg;
struct iovec my_iov;
struct iovec *curr_iov;
int curr_iovlen;
char __user *curr_start;
u32 hdr_size;
int curr_left;
int bytes_to_send;
int bytes_sent;
int res;
/* Handle special cases where there is no connection */
if (unlikely(sock->state != SS_CONNECTED)) {
if (sock->state == SS_UNCONNECTED)
return send_packet(iocb, sock, m, total_len);
else if (sock->state == SS_DISCONNECTING)
return -EPIPE;
else
return -ENOTCONN;
}
if (unlikely(m->msg_name))
return -EISCONN;
/*
* Send each iovec entry using one or more messages
*
* Note: This algorithm is good for the most likely case
* (i.e. one large iovec entry), but could be improved to pass sets
* of small iovec entries into send_packet().
*/
curr_iov = m->msg_iov;
curr_iovlen = m->msg_iovlen;
my_msg.msg_iov = &my_iov;
my_msg.msg_iovlen = 1;
my_msg.msg_flags = m->msg_flags;
my_msg.msg_name = NULL;
bytes_sent = 0;
tport = tipc_sk(sock->sk)->p;
hdr_size = msg_hdr_sz(&tport->phdr);
while (curr_iovlen--) {
curr_start = curr_iov->iov_base;
curr_left = curr_iov->iov_len;
while (curr_left) {
bytes_to_send = tport->max_pkt - hdr_size;
if (bytes_to_send > TIPC_MAX_USER_MSG_SIZE)
bytes_to_send = TIPC_MAX_USER_MSG_SIZE;
if (curr_left < bytes_to_send)
bytes_to_send = curr_left;
my_iov.iov_base = curr_start;
my_iov.iov_len = bytes_to_send;
if ((res = send_packet(iocb, sock, &my_msg, 0)) < 0) {
if (bytes_sent != 0)
res = bytes_sent;
return res;
}
curr_left -= bytes_to_send;
curr_start += bytes_to_send;
bytes_sent += bytes_to_send;
}
curr_iov++;
}
return bytes_sent;
}
/**
* auto_connect - complete connection setup to a remote port
* @sock: socket structure
* @tsock: TIPC-specific socket structure
* @msg: peer's response message
*
* Returns 0 on success, errno otherwise
*/
static int auto_connect(struct socket *sock, struct tipc_sock *tsock,
struct tipc_msg *msg)
{
struct tipc_portid peer;
if (msg_errcode(msg)) {
sock->state = SS_DISCONNECTING;
return -ECONNREFUSED;
}
peer.ref = msg_origport(msg);
peer.node = msg_orignode(msg);
tipc_connect2port(tsock->p->ref, &peer);
tipc_set_portimportance(tsock->p->ref, msg_importance(msg));
sock->state = SS_CONNECTED;
return 0;
}
/**
* set_orig_addr - capture sender's address for received message
* @m: descriptor for message info
* @msg: received message header
*
* Note: Address is not captured if not requested by receiver.
*/
static void set_orig_addr(struct msghdr *m, struct tipc_msg *msg)
{
struct sockaddr_tipc *addr = (struct sockaddr_tipc *)m->msg_name;
if (addr) {
addr->family = AF_TIPC;
addr->addrtype = TIPC_ADDR_ID;
addr->addr.id.ref = msg_origport(msg);
addr->addr.id.node = msg_orignode(msg);
addr->addr.name.domain = 0; /* could leave uninitialized */
addr->scope = 0; /* could leave uninitialized */
m->msg_namelen = sizeof(struct sockaddr_tipc);
}
}
/**
* anc_data_recv - optionally capture ancillary data for received message
* @m: descriptor for message info
* @msg: received message header
* @tport: TIPC port associated with message
*
* Note: Ancillary data is not captured if not requested by receiver.
*
* Returns 0 if successful, otherwise errno
*/
static int anc_data_recv(struct msghdr *m, struct tipc_msg *msg,
struct tipc_port *tport)
{
u32 anc_data[3];
u32 err;
u32 dest_type;
int has_name;
int res;
if (likely(m->msg_controllen == 0))
return 0;
/* Optionally capture errored message object(s) */
err = msg ? msg_errcode(msg) : 0;
if (unlikely(err)) {
anc_data[0] = err;
anc_data[1] = msg_data_sz(msg);
if ((res = put_cmsg(m, SOL_TIPC, TIPC_ERRINFO, 8, anc_data)))
return res;
if (anc_data[1] &&
(res = put_cmsg(m, SOL_TIPC, TIPC_RETDATA, anc_data[1],
msg_data(msg))))
return res;
}
/* Optionally capture message destination object */
dest_type = msg ? msg_type(msg) : TIPC_DIRECT_MSG;
switch (dest_type) {
case TIPC_NAMED_MSG:
has_name = 1;
anc_data[0] = msg_nametype(msg);
anc_data[1] = msg_namelower(msg);
anc_data[2] = msg_namelower(msg);
break;
case TIPC_MCAST_MSG:
has_name = 1;
anc_data[0] = msg_nametype(msg);
anc_data[1] = msg_namelower(msg);
anc_data[2] = msg_nameupper(msg);
break;
case TIPC_CONN_MSG:
has_name = (tport->conn_type != 0);
anc_data[0] = tport->conn_type;
anc_data[1] = tport->conn_instance;
anc_data[2] = tport->conn_instance;
break;
default:
has_name = 0;
}
if (has_name &&
(res = put_cmsg(m, SOL_TIPC, TIPC_DESTNAME, 12, anc_data)))
return res;
return 0;
}
/**
* recv_msg - receive packet-oriented message
* @iocb: (unused)
* @m: descriptor for message info
* @buf_len: total size of user buffer area
* @flags: receive flags
*
* Used for SOCK_DGRAM, SOCK_RDM, and SOCK_SEQPACKET messages.
* If the complete message doesn't fit in user area, truncate it.
*
* Returns size of returned message data, errno otherwise
*/
static int recv_msg(struct kiocb *iocb, struct socket *sock,
struct msghdr *m, size_t buf_len, int flags)
{
struct tipc_sock *tsock = tipc_sk(sock->sk);
struct sk_buff *buf;
struct tipc_msg *msg;
unsigned int q_len;
unsigned int sz;
u32 err;
int res;
/* Currently doesn't support receiving into multiple iovec entries */
if (m->msg_iovlen != 1)
return -EOPNOTSUPP;
/* Catch invalid receive attempts */
if (unlikely(!buf_len))
return -EINVAL;
if (sock->type == SOCK_SEQPACKET) {
if (unlikely(sock->state == SS_UNCONNECTED))
return -ENOTCONN;
if (unlikely((sock->state == SS_DISCONNECTING) &&
(skb_queue_len(&sock->sk->sk_receive_queue) == 0)))
return -ENOTCONN;
}
/* Look for a message in receive queue; wait if necessary */
if (unlikely(down_interruptible(&tsock->sem)))
return -ERESTARTSYS;
restart:
if (unlikely((skb_queue_len(&sock->sk->sk_receive_queue) == 0) &&
(flags & MSG_DONTWAIT))) {
res = -EWOULDBLOCK;
goto exit;
}
if ((res = wait_event_interruptible(
*sock->sk->sk_sleep,
((q_len = skb_queue_len(&sock->sk->sk_receive_queue)) ||
(sock->state == SS_DISCONNECTING))) )) {
goto exit;
}
/* Catch attempt to receive on an already terminated connection */
/* [THIS CHECK MAY OVERLAP WITH AN EARLIER CHECK] */
if (!q_len) {
res = -ENOTCONN;
goto exit;
}
/* Get access to first message in receive queue */
buf = skb_peek(&sock->sk->sk_receive_queue);
msg = buf_msg(buf);
sz = msg_data_sz(msg);
err = msg_errcode(msg);
/* Complete connection setup for an implied connect */
if (unlikely(sock->state == SS_CONNECTING)) {
if ((res = auto_connect(sock, tsock, msg)))
goto exit;
}
/* Discard an empty non-errored message & try again */
if ((!sz) && (!err)) {
advance_queue(tsock);
goto restart;
}
/* Capture sender's address (optional) */
set_orig_addr(m, msg);
/* Capture ancillary data (optional) */
if ((res = anc_data_recv(m, msg, tsock->p)))
goto exit;
/* Capture message data (if valid) & compute return value (always) */
if (!err) {
if (unlikely(buf_len < sz)) {
sz = buf_len;
m->msg_flags |= MSG_TRUNC;
}
if (unlikely(copy_to_user(m->msg_iov->iov_base, msg_data(msg),
sz))) {
res = -EFAULT;
goto exit;
}
res = sz;
} else {
if ((sock->state == SS_READY) ||
((err == TIPC_CONN_SHUTDOWN) || m->msg_control))
res = 0;
else
res = -ECONNRESET;
}
/* Consume received message (optional) */
if (likely(!(flags & MSG_PEEK))) {
if (unlikely(++tsock->p->conn_unacked >= TIPC_FLOW_CONTROL_WIN))
tipc_acknowledge(tsock->p->ref, tsock->p->conn_unacked);
advance_queue(tsock);
}
exit:
up(&tsock->sem);
return res;
}
/**
* recv_stream - receive stream-oriented data
* @iocb: (unused)
* @m: descriptor for message info
* @buf_len: total size of user buffer area
* @flags: receive flags
*
* Used for SOCK_STREAM messages only. If not enough data is available
* will optionally wait for more; never truncates data.
*
* Returns size of returned message data, errno otherwise
*/
static int recv_stream(struct kiocb *iocb, struct socket *sock,
struct msghdr *m, size_t buf_len, int flags)
{
struct tipc_sock *tsock = tipc_sk(sock->sk);
struct sk_buff *buf;
struct tipc_msg *msg;
unsigned int q_len;
unsigned int sz;
int sz_to_copy;
int sz_copied = 0;
int needed;
char __user *crs = m->msg_iov->iov_base;
unsigned char *buf_crs;
u32 err;
int res;
/* Currently doesn't support receiving into multiple iovec entries */
if (m->msg_iovlen != 1)
return -EOPNOTSUPP;
/* Catch invalid receive attempts */
if (unlikely(!buf_len))
return -EINVAL;
if (unlikely(sock->state == SS_DISCONNECTING)) {
if (skb_queue_len(&sock->sk->sk_receive_queue) == 0)
return -ENOTCONN;
} else if (unlikely(sock->state != SS_CONNECTED))
return -ENOTCONN;
/* Look for a message in receive queue; wait if necessary */
if (unlikely(down_interruptible(&tsock->sem)))
return -ERESTARTSYS;
restart:
if (unlikely((skb_queue_len(&sock->sk->sk_receive_queue) == 0) &&
(flags & MSG_DONTWAIT))) {
res = -EWOULDBLOCK;
goto exit;
}
if ((res = wait_event_interruptible(
*sock->sk->sk_sleep,
((q_len = skb_queue_len(&sock->sk->sk_receive_queue)) ||
(sock->state == SS_DISCONNECTING))) )) {
goto exit;
}
/* Catch attempt to receive on an already terminated connection */
/* [THIS CHECK MAY OVERLAP WITH AN EARLIER CHECK] */
if (!q_len) {
res = -ENOTCONN;
goto exit;
}
/* Get access to first message in receive queue */
buf = skb_peek(&sock->sk->sk_receive_queue);
msg = buf_msg(buf);
sz = msg_data_sz(msg);
err = msg_errcode(msg);
/* Discard an empty non-errored message & try again */
if ((!sz) && (!err)) {
advance_queue(tsock);
goto restart;
}
/* Optionally capture sender's address & ancillary data of first msg */
if (sz_copied == 0) {
set_orig_addr(m, msg);
if ((res = anc_data_recv(m, msg, tsock->p)))
goto exit;
}
/* Capture message data (if valid) & compute return value (always) */
if (!err) {
buf_crs = (unsigned char *)(TIPC_SKB_CB(buf)->handle);
sz = skb_tail_pointer(buf) - buf_crs;
needed = (buf_len - sz_copied);
sz_to_copy = (sz <= needed) ? sz : needed;
if (unlikely(copy_to_user(crs, buf_crs, sz_to_copy))) {
res = -EFAULT;
goto exit;
}
sz_copied += sz_to_copy;
if (sz_to_copy < sz) {
if (!(flags & MSG_PEEK))
TIPC_SKB_CB(buf)->handle = buf_crs + sz_to_copy;
goto exit;
}
crs += sz_to_copy;
} else {
if (sz_copied != 0)
goto exit; /* can't add error msg to valid data */
if ((err == TIPC_CONN_SHUTDOWN) || m->msg_control)
res = 0;
else
res = -ECONNRESET;
}
/* Consume received message (optional) */
if (likely(!(flags & MSG_PEEK))) {
if (unlikely(++tsock->p->conn_unacked >= TIPC_FLOW_CONTROL_WIN))
tipc_acknowledge(tsock->p->ref, tsock->p->conn_unacked);
advance_queue(tsock);
}
/* Loop around if more data is required */
if ((sz_copied < buf_len) /* didn't get all requested data */
&& (flags & MSG_WAITALL) /* ... and need to wait for more */
&& (!(flags & MSG_PEEK)) /* ... and aren't just peeking at data */
&& (!err) /* ... and haven't reached a FIN */
)
goto restart;
exit:
up(&tsock->sem);
return sz_copied ? sz_copied : res;
}
/**
* queue_overloaded - test if queue overload condition exists
* @queue_size: current size of queue
* @base: nominal maximum size of queue
* @msg: message to be added to queue
*
* Returns 1 if queue is currently overloaded, 0 otherwise
*/
static int queue_overloaded(u32 queue_size, u32 base, struct tipc_msg *msg)
{
u32 threshold;
u32 imp = msg_importance(msg);
if (imp == TIPC_LOW_IMPORTANCE)
threshold = base;
else if (imp == TIPC_MEDIUM_IMPORTANCE)
threshold = base * 2;
else if (imp == TIPC_HIGH_IMPORTANCE)
threshold = base * 100;
else
return 0;
if (msg_connected(msg))
threshold *= 4;
return (queue_size > threshold);
}
/**
* async_disconnect - wrapper function used to disconnect port
* @portref: TIPC port reference (passed as pointer-sized value)
*/
static void async_disconnect(unsigned long portref)
{
tipc_disconnect((u32)portref);
}
/**
* dispatch - handle arriving message
* @tport: TIPC port that received message
* @buf: message
*
* Called with port locked. Must not take socket lock to avoid deadlock risk.
*
* Returns TIPC error status code (TIPC_OK if message is not to be rejected)
*/
static u32 dispatch(struct tipc_port *tport, struct sk_buff *buf)
{
struct tipc_msg *msg = buf_msg(buf);
struct tipc_sock *tsock = (struct tipc_sock *)tport->usr_handle;
struct socket *sock;
u32 recv_q_len;
/* Reject message if socket is closing */
if (!tsock)
return TIPC_ERR_NO_PORT;
/* Reject message if it is wrong sort of message for socket */
/*
* WOULD IT BE BETTER TO JUST DISCARD THESE MESSAGES INSTEAD?
* "NO PORT" ISN'T REALLY THE RIGHT ERROR CODE, AND THERE MAY
* BE SECURITY IMPLICATIONS INHERENT IN REJECTING INVALID TRAFFIC
*/
sock = tsock->sk.sk_socket;
if (sock->state == SS_READY) {
if (msg_connected(msg)) {
msg_dbg(msg, "dispatch filter 1\n");
return TIPC_ERR_NO_PORT;
}
} else {
if (msg_mcast(msg)) {
msg_dbg(msg, "dispatch filter 2\n");
return TIPC_ERR_NO_PORT;
}
if (sock->state == SS_CONNECTED) {
if (!msg_connected(msg)) {
msg_dbg(msg, "dispatch filter 3\n");
return TIPC_ERR_NO_PORT;
}
}
else if (sock->state == SS_CONNECTING) {
if (!msg_connected(msg) && (msg_errcode(msg) == 0)) {
msg_dbg(msg, "dispatch filter 4\n");
return TIPC_ERR_NO_PORT;
}
}
else if (sock->state == SS_LISTENING) {
if (msg_connected(msg) || msg_errcode(msg)) {
msg_dbg(msg, "dispatch filter 5\n");
return TIPC_ERR_NO_PORT;
}
}
else if (sock->state == SS_DISCONNECTING) {
msg_dbg(msg, "dispatch filter 6\n");
return TIPC_ERR_NO_PORT;
}
else /* (sock->state == SS_UNCONNECTED) */ {
if (msg_connected(msg) || msg_errcode(msg)) {
msg_dbg(msg, "dispatch filter 7\n");
return TIPC_ERR_NO_PORT;
}
}
}
/* Reject message if there isn't room to queue it */
if (unlikely((u32)atomic_read(&tipc_queue_size) >
OVERLOAD_LIMIT_BASE)) {
if (queue_overloaded(atomic_read(&tipc_queue_size),
OVERLOAD_LIMIT_BASE, msg))
return TIPC_ERR_OVERLOAD;
}
recv_q_len = skb_queue_len(&tsock->sk.sk_receive_queue);
if (unlikely(recv_q_len > (OVERLOAD_LIMIT_BASE / 2))) {
if (queue_overloaded(recv_q_len,
OVERLOAD_LIMIT_BASE / 2, msg))
return TIPC_ERR_OVERLOAD;
}
/* Initiate connection termination for an incoming 'FIN' */
if (unlikely(msg_errcode(msg) && (sock->state == SS_CONNECTED))) {
sock->state = SS_DISCONNECTING;
/* Note: Use signal since port lock is already taken! */
tipc_k_signal((Handler)async_disconnect, tport->ref);
}
/* Enqueue message (finally!) */
msg_dbg(msg,"<DISP<: ");
TIPC_SKB_CB(buf)->handle = msg_data(msg);
atomic_inc(&tipc_queue_size);
skb_queue_tail(&sock->sk->sk_receive_queue, buf);
if (waitqueue_active(sock->sk->sk_sleep))
wake_up_interruptible(sock->sk->sk_sleep);
return TIPC_OK;
}
/**
* wakeupdispatch - wake up port after congestion
* @tport: port to wakeup
*
* Called with port lock on.
*/
static void wakeupdispatch(struct tipc_port *tport)
{
struct tipc_sock *tsock = (struct tipc_sock *)tport->usr_handle;
if (waitqueue_active(tsock->sk.sk_sleep))
wake_up_interruptible(tsock->sk.sk_sleep);
}
/**
* connect - establish a connection to another TIPC port
* @sock: socket structure
* @dest: socket address for destination port
* @destlen: size of socket address data structure
* @flags: (unused)
*
* Returns 0 on success, errno otherwise
*/
static int connect(struct socket *sock, struct sockaddr *dest, int destlen,
int flags)
{
struct tipc_sock *tsock = tipc_sk(sock->sk);
struct sockaddr_tipc *dst = (struct sockaddr_tipc *)dest;
struct msghdr m = {NULL,};
struct sk_buff *buf;
struct tipc_msg *msg;
int res;
/* For now, TIPC does not allow use of connect() with DGRAM or RDM types */
if (sock->state == SS_READY)
return -EOPNOTSUPP;
/* Issue Posix-compliant error code if socket is in the wrong state */
if (sock->state == SS_LISTENING)
return -EOPNOTSUPP;
if (sock->state == SS_CONNECTING)
return -EALREADY;
if (sock->state != SS_UNCONNECTED)
return -EISCONN;
/*
* Reject connection attempt using multicast address
*
* Note: send_msg() validates the rest of the address fields,
* so there's no need to do it here
*/
if (dst->addrtype == TIPC_ADDR_MCAST)
return -EINVAL;
/* Send a 'SYN-' to destination */
m.msg_name = dest;
m.msg_namelen = destlen;
if ((res = send_msg(NULL, sock, &m, 0)) < 0) {
sock->state = SS_DISCONNECTING;
return res;
}
if (down_interruptible(&tsock->sem))
return -ERESTARTSYS;
/* Wait for destination's 'ACK' response */
res = wait_event_interruptible_timeout(*sock->sk->sk_sleep,
skb_queue_len(&sock->sk->sk_receive_queue),
sock->sk->sk_rcvtimeo);
buf = skb_peek(&sock->sk->sk_receive_queue);
if (res > 0) {
msg = buf_msg(buf);
res = auto_connect(sock, tsock, msg);
if (!res) {
if (!msg_data_sz(msg))
advance_queue(tsock);
}
} else {
if (res == 0) {
res = -ETIMEDOUT;
} else
{ /* leave "res" unchanged */ }
sock->state = SS_DISCONNECTING;
}
up(&tsock->sem);
return res;
}
/**
* listen - allow socket to listen for incoming connections
* @sock: socket structure
* @len: (unused)
*
* Returns 0 on success, errno otherwise
*/
static int listen(struct socket *sock, int len)
{
/* REQUIRES SOCKET LOCKING OF SOME SORT? */
if (sock->state == SS_READY)
return -EOPNOTSUPP;
if (sock->state != SS_UNCONNECTED)
return -EINVAL;
sock->state = SS_LISTENING;
return 0;
}
/**
* accept - wait for connection request
* @sock: listening socket
* @newsock: new socket that is to be connected
* @flags: file-related flags associated with socket
*
* Returns 0 on success, errno otherwise
*/
static int accept(struct socket *sock, struct socket *newsock, int flags)
{
struct tipc_sock *tsock = tipc_sk(sock->sk);
struct sk_buff *buf;
int res = -EFAULT;
if (sock->state == SS_READY)
return -EOPNOTSUPP;
if (sock->state != SS_LISTENING)
return -EINVAL;
if (unlikely((skb_queue_len(&sock->sk->sk_receive_queue) == 0) &&
(flags & O_NONBLOCK)))
return -EWOULDBLOCK;
if (down_interruptible(&tsock->sem))
return -ERESTARTSYS;
if (wait_event_interruptible(*sock->sk->sk_sleep,
skb_queue_len(&sock->sk->sk_receive_queue))) {
res = -ERESTARTSYS;
goto exit;
}
buf = skb_peek(&sock->sk->sk_receive_queue);
res = tipc_create(newsock, 0);
if (!res) {
struct tipc_sock *new_tsock = tipc_sk(newsock->sk);
struct tipc_portid id;
struct tipc_msg *msg = buf_msg(buf);
u32 new_ref = new_tsock->p->ref;
id.ref = msg_origport(msg);
id.node = msg_orignode(msg);
tipc_connect2port(new_ref, &id);
newsock->state = SS_CONNECTED;
tipc_set_portimportance(new_ref, msg_importance(msg));
if (msg_named(msg)) {
new_tsock->p->conn_type = msg_nametype(msg);
new_tsock->p->conn_instance = msg_nameinst(msg);
}
/*
* Respond to 'SYN-' by discarding it & returning 'ACK'-.
* Respond to 'SYN+' by queuing it on new socket.
*/
msg_dbg(msg,"<ACC<: ");
if (!msg_data_sz(msg)) {
struct msghdr m = {NULL,};
send_packet(NULL, newsock, &m, 0);
advance_queue(tsock);
} else {
sock_lock(tsock);
skb_dequeue(&sock->sk->sk_receive_queue);
sock_unlock(tsock);
skb_queue_head(&newsock->sk->sk_receive_queue, buf);
}
}
exit:
up(&tsock->sem);
return res;
}
/**
* shutdown - shutdown socket connection
* @sock: socket structure
* @how: direction to close (unused; always treated as read + write)
*
* Terminates connection (if necessary), then purges socket's receive queue.
*
* Returns 0 on success, errno otherwise
*/
static int shutdown(struct socket *sock, int how)
{
struct tipc_sock* tsock = tipc_sk(sock->sk);
struct sk_buff *buf;
int res;
/* Could return -EINVAL for an invalid "how", but why bother? */
if (down_interruptible(&tsock->sem))
return -ERESTARTSYS;
sock_lock(tsock);
switch (sock->state) {
case SS_CONNECTED:
/* Send 'FIN+' or 'FIN-' message to peer */
sock_unlock(tsock);
restart:
if ((buf = skb_dequeue(&sock->sk->sk_receive_queue))) {
atomic_dec(&tipc_queue_size);
if (TIPC_SKB_CB(buf)->handle != msg_data(buf_msg(buf))) {
buf_discard(buf);
goto restart;
}
tipc_reject_msg(buf, TIPC_CONN_SHUTDOWN);
}
else {
tipc_shutdown(tsock->p->ref);
}
sock_lock(tsock);
/* fall through */
case SS_DISCONNECTING:
/* Discard any unreceived messages */
while ((buf = skb_dequeue(&sock->sk->sk_receive_queue))) {
atomic_dec(&tipc_queue_size);
buf_discard(buf);
}
tsock->p->conn_unacked = 0;
/* fall through */
case SS_CONNECTING:
sock->state = SS_DISCONNECTING;
res = 0;
break;
default:
res = -ENOTCONN;
}
sock_unlock(tsock);
up(&tsock->sem);
return res;
}
/**
* setsockopt - set socket option
* @sock: socket structure
* @lvl: option level
* @opt: option identifier
* @ov: pointer to new option value
* @ol: length of option value
*
* For stream sockets only, accepts and ignores all IPPROTO_TCP options
* (to ease compatibility).
*
* Returns 0 on success, errno otherwise
*/
static int setsockopt(struct socket *sock,
int lvl, int opt, char __user *ov, int ol)
{
struct tipc_sock *tsock = tipc_sk(sock->sk);
u32 value;
int res;
if ((lvl == IPPROTO_TCP) && (sock->type == SOCK_STREAM))
return 0;
if (lvl != SOL_TIPC)
return -ENOPROTOOPT;
if (ol < sizeof(value))
return -EINVAL;
if ((res = get_user(value, (u32 __user *)ov)))
return res;
if (down_interruptible(&tsock->sem))
return -ERESTARTSYS;
switch (opt) {
case TIPC_IMPORTANCE:
res = tipc_set_portimportance(tsock->p->ref, value);
break;
case TIPC_SRC_DROPPABLE:
if (sock->type != SOCK_STREAM)
res = tipc_set_portunreliable(tsock->p->ref, value);
else
res = -ENOPROTOOPT;
break;
case TIPC_DEST_DROPPABLE:
res = tipc_set_portunreturnable(tsock->p->ref, value);
break;
case TIPC_CONN_TIMEOUT:
sock->sk->sk_rcvtimeo = (value * HZ / 1000);
break;
default:
res = -EINVAL;
}
up(&tsock->sem);
return res;
}
/**
* getsockopt - get socket option
* @sock: socket structure
* @lvl: option level
* @opt: option identifier
* @ov: receptacle for option value
* @ol: receptacle for length of option value
*
* For stream sockets only, returns 0 length result for all IPPROTO_TCP options
* (to ease compatibility).
*
* Returns 0 on success, errno otherwise
*/
static int getsockopt(struct socket *sock,
int lvl, int opt, char __user *ov, int __user *ol)
{
struct tipc_sock *tsock = tipc_sk(sock->sk);
int len;
u32 value;
int res;
if ((lvl == IPPROTO_TCP) && (sock->type == SOCK_STREAM))
return put_user(0, ol);
if (lvl != SOL_TIPC)
return -ENOPROTOOPT;
if ((res = get_user(len, ol)))
return res;
if (down_interruptible(&tsock->sem))
return -ERESTARTSYS;
switch (opt) {
case TIPC_IMPORTANCE:
res = tipc_portimportance(tsock->p->ref, &value);
break;
case TIPC_SRC_DROPPABLE:
res = tipc_portunreliable(tsock->p->ref, &value);
break;
case TIPC_DEST_DROPPABLE:
res = tipc_portunreturnable(tsock->p->ref, &value);
break;
case TIPC_CONN_TIMEOUT:
value = (sock->sk->sk_rcvtimeo * 1000) / HZ;
break;
default:
res = -EINVAL;
}
if (res) {
/* "get" failed */
}
else if (len < sizeof(value)) {
res = -EINVAL;
}
else if ((res = copy_to_user(ov, &value, sizeof(value)))) {
/* couldn't return value */
}
else {
res = put_user(sizeof(value), ol);
}
up(&tsock->sem);
return res;
}
/**
* Protocol switches for the various types of TIPC sockets
*/
static struct proto_ops msg_ops = {
.owner = THIS_MODULE,
.family = AF_TIPC,
.release = release,
.bind = bind,
.connect = connect,
.socketpair = sock_no_socketpair,
.accept = accept,
.getname = get_name,
.poll = poll,
.ioctl = sock_no_ioctl,
.listen = listen,
.shutdown = shutdown,
.setsockopt = setsockopt,
.getsockopt = getsockopt,
.sendmsg = send_msg,
.recvmsg = recv_msg,
.mmap = sock_no_mmap,
.sendpage = sock_no_sendpage
};
static struct proto_ops packet_ops = {
.owner = THIS_MODULE,
.family = AF_TIPC,
.release = release,
.bind = bind,
.connect = connect,
.socketpair = sock_no_socketpair,
.accept = accept,
.getname = get_name,
.poll = poll,
.ioctl = sock_no_ioctl,
.listen = listen,
.shutdown = shutdown,
.setsockopt = setsockopt,
.getsockopt = getsockopt,
.sendmsg = send_packet,
.recvmsg = recv_msg,
.mmap = sock_no_mmap,
.sendpage = sock_no_sendpage
};
static struct proto_ops stream_ops = {
.owner = THIS_MODULE,
.family = AF_TIPC,
.release = release,
.bind = bind,
.connect = connect,
.socketpair = sock_no_socketpair,
.accept = accept,
.getname = get_name,
.poll = poll,
.ioctl = sock_no_ioctl,
.listen = listen,
.shutdown = shutdown,
.setsockopt = setsockopt,
.getsockopt = getsockopt,
.sendmsg = send_stream,
.recvmsg = recv_stream,
.mmap = sock_no_mmap,
.sendpage = sock_no_sendpage
};
static struct net_proto_family tipc_family_ops = {
.owner = THIS_MODULE,
.family = AF_TIPC,
.create = tipc_create
};
static struct proto tipc_proto = {
.name = "TIPC",
.owner = THIS_MODULE,
.obj_size = sizeof(struct tipc_sock)
};
/**
* tipc_socket_init - initialize TIPC socket interface
*
* Returns 0 on success, errno otherwise
*/
int tipc_socket_init(void)
{
int res;
res = proto_register(&tipc_proto, 1);
if (res) {
err("Failed to register TIPC protocol type\n");
goto out;
}
res = sock_register(&tipc_family_ops);
if (res) {
err("Failed to register TIPC socket type\n");
proto_unregister(&tipc_proto);
goto out;
}
sockets_enabled = 1;
out:
return res;
}
/**
* tipc_socket_stop - stop TIPC socket interface
*/
void tipc_socket_stop(void)
{
if (!sockets_enabled)
return;
sockets_enabled = 0;
sock_unregister(tipc_family_ops.family);
proto_unregister(&tipc_proto);
}