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socket.c
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socket.c
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/*
* net/tipc/socket.c: TIPC socket API
*
* Copyright (c) 2001-2007, Ericsson AB
* Copyright (c) 2004-2008, 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 <linux/export.h>
#include <net/sock.h>
#include "core.h"
#include "port.h"
#define SS_LISTENING -1 /* socket is listening */
#define SS_READY -2 /* socket is connectionless */
#define OVERLOAD_LIMIT_BASE 5000
#define CONN_TIMEOUT_DEFAULT 8000 /* default connect timeout = 8s */
struct tipc_sock {
struct sock sk;
struct tipc_port *p;
struct tipc_portid peer_name;
unsigned int conn_timeout;
};
#define tipc_sk(sk) ((struct tipc_sock *)(sk))
#define tipc_sk_port(sk) ((struct tipc_port *)(tipc_sk(sk)->p))
#define tipc_rx_ready(sock) (!skb_queue_empty(&sock->sk->sk_receive_queue) || \
(sock->state == SS_DISCONNECTING))
static int backlog_rcv(struct sock *sk, struct sk_buff *skb);
static u32 dispatch(struct tipc_port *tport, struct sk_buff *buf);
static void wakeupdispatch(struct tipc_port *tport);
static const struct proto_ops packet_ops;
static const struct proto_ops stream_ops;
static const struct proto_ops msg_ops;
static struct proto tipc_proto;
static int sockets_enabled;
static atomic_t tipc_queue_size = ATOMIC_INIT(0);
/*
* Revised TIPC socket locking policy:
*
* Most socket operations take the standard socket lock when they start
* and hold it until they finish (or until they need to sleep). Acquiring
* this lock grants the owner exclusive access to the fields of the socket
* data structures, with the exception of the backlog queue. A few socket
* operations can be done without taking the socket lock because they only
* read socket information that never changes during the life of the socket.
*
* Socket operations may acquire the lock for the associated TIPC port if they
* need to perform an operation on the port. If any routine needs to acquire
* both the socket lock and the port lock it must take the socket lock first
* to avoid the risk of deadlock.
*
* The dispatcher handling incoming messages cannot grab the socket lock in
* the standard fashion, since invoked it runs at the BH level and cannot block.
* Instead, it checks to see if the socket lock is currently owned by someone,
* and either handles the message itself or adds it to the socket's backlog
* queue; in the latter case the queued message is processed once the process
* owning the socket lock releases it.
*
* NOTE: Releasing the socket lock while an operation is sleeping overcomes
* the problem of a blocked socket operation preventing any other operations
* from occurring. However, applications must be careful if they have
* multiple threads trying to send (or receive) on the same socket, as these
* operations might interfere with each other. For example, doing a connect
* and a receive at the same time might allow the receive to consume the
* ACK message meant for the connect. While additional work could be done
* to try and overcome this, it doesn't seem to be worthwhile at the present.
*
* NOTE: Releasing the socket lock while an operation is sleeping also ensures
* that another operation that must be performed in a non-blocking manner is
* not delayed for very long because the lock has already been taken.
*
* NOTE: This code assumes that certain fields of a port/socket pair are
* constant over its lifetime; such fields can be examined without taking
* the socket lock and/or port lock, and do not need to be re-read even
* after resuming processing after waiting. These fields include:
* - socket type
* - pointer to socket sk structure (aka tipc_sock structure)
* - pointer to port structure
* - port reference
*/
/**
* advance_rx_queue - discard first buffer in socket receive queue
*
* Caller must hold socket lock
*/
static void advance_rx_queue(struct sock *sk)
{
buf_discard(__skb_dequeue(&sk->sk_receive_queue));
atomic_dec(&tipc_queue_size);
}
/**
* discard_rx_queue - discard all buffers in socket receive queue
*
* Caller must hold socket lock
*/
static void discard_rx_queue(struct sock *sk)
{
struct sk_buff *buf;
while ((buf = __skb_dequeue(&sk->sk_receive_queue))) {
atomic_dec(&tipc_queue_size);
buf_discard(buf);
}
}
/**
* reject_rx_queue - reject all buffers in socket receive queue
*
* Caller must hold socket lock
*/
static void reject_rx_queue(struct sock *sk)
{
struct sk_buff *buf;
while ((buf = __skb_dequeue(&sk->sk_receive_queue))) {
tipc_reject_msg(buf, TIPC_ERR_NO_PORT);
atomic_dec(&tipc_queue_size);
}
}
/**
* tipc_create - create a TIPC socket
* @net: network namespace (must be default network)
* @sock: pre-allocated socket structure
* @protocol: protocol indicator (must be 0)
* @kern: caused by kernel or by userspace?
*
* This routine creates additional data structures used by the TIPC socket,
* initializes them, and links them together.
*
* Returns 0 on success, errno otherwise
*/
static int tipc_create(struct net *net, struct socket *sock, int protocol,
int kern)
{
const struct proto_ops *ops;
socket_state state;
struct sock *sk;
struct tipc_port *tp_ptr;
/* Validate arguments */
if (unlikely(protocol != 0))
return -EPROTONOSUPPORT;
switch (sock->type) {
case SOCK_STREAM:
ops = &stream_ops;
state = SS_UNCONNECTED;
break;
case SOCK_SEQPACKET:
ops = &packet_ops;
state = SS_UNCONNECTED;
break;
case SOCK_DGRAM:
case SOCK_RDM:
ops = &msg_ops;
state = SS_READY;
break;
default:
return -EPROTOTYPE;
}
/* Allocate socket's protocol area */
sk = sk_alloc(net, AF_TIPC, GFP_KERNEL, &tipc_proto);
if (sk == NULL)
return -ENOMEM;
/* Allocate TIPC port for socket to use */
tp_ptr = tipc_createport_raw(sk, &dispatch, &wakeupdispatch,
TIPC_LOW_IMPORTANCE);
if (unlikely(!tp_ptr)) {
sk_free(sk);
return -ENOMEM;
}
/* Finish initializing socket data structures */
sock->ops = ops;
sock->state = state;
sock_init_data(sock, sk);
sk->sk_backlog_rcv = backlog_rcv;
tipc_sk(sk)->p = tp_ptr;
tipc_sk(sk)->conn_timeout = CONN_TIMEOUT_DEFAULT;
spin_unlock_bh(tp_ptr->lock);
if (sock->state == SS_READY) {
tipc_set_portunreturnable(tp_ptr->ref, 1);
if (sock->type == SOCK_DGRAM)
tipc_set_portunreliable(tp_ptr->ref, 1);
}
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 sock *sk = sock->sk;
struct tipc_port *tport;
struct sk_buff *buf;
int res;
/*
* Exit if socket isn't fully initialized (occurs when a failed accept()
* releases a pre-allocated child socket that was never used)
*/
if (sk == NULL)
return 0;
tport = tipc_sk_port(sk);
lock_sock(sk);
/*
* Reject all unreceived messages, except on an active connection
* (which disconnects locally & sends a 'FIN+' to peer)
*/
while (sock->state != SS_DISCONNECTING) {
buf = __skb_dequeue(&sk->sk_receive_queue);
if (buf == NULL)
break;
atomic_dec(&tipc_queue_size);
if (TIPC_SKB_CB(buf)->handle != 0)
buf_discard(buf);
else {
if ((sock->state == SS_CONNECTING) ||
(sock->state == SS_CONNECTED)) {
sock->state = SS_DISCONNECTING;
tipc_disconnect(tport->ref);
}
tipc_reject_msg(buf, TIPC_ERR_NO_PORT);
}
}
/*
* Delete TIPC port; this ensures no more messages are queued
* (also disconnects an active connection & sends a 'FIN-' to peer)
*/
res = tipc_deleteport(tport->ref);
/* Discard any remaining (connection-based) messages in receive queue */
discard_rx_queue(sk);
/* Reject any messages that accumulated in backlog queue */
sock->state = SS_DISCONNECTING;
release_sock(sk);
sock_put(sk);
sock->sk = NULL;
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
*
* NOTE: This routine doesn't need to take the socket lock since it doesn't
* access any non-constant socket information.
*/
static int bind(struct socket *sock, struct sockaddr *uaddr, int uaddr_len)
{
struct sockaddr_tipc *addr = (struct sockaddr_tipc *)uaddr;
u32 portref = tipc_sk_port(sock->sk)->ref;
if (unlikely(!uaddr_len))
return tipc_withdraw(portref, 0, NULL);
if (uaddr_len < sizeof(struct sockaddr_tipc))
return -EINVAL;
if (addr->family != AF_TIPC)
return -EAFNOSUPPORT;
if (addr->addrtype == TIPC_ADDR_NAME)
addr->addr.nameseq.upper = addr->addr.nameseq.lower;
else if (addr->addrtype != TIPC_ADDR_NAMESEQ)
return -EAFNOSUPPORT;
return (addr->scope > 0) ?
tipc_publish(portref, addr->scope, &addr->addr.nameseq) :
tipc_withdraw(portref, -addr->scope, &addr->addr.nameseq);
}
/**
* 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 = own ID, 1 = current peer ID, 2 = current/former peer ID
*
* Returns 0 on success, errno otherwise
*
* NOTE: This routine doesn't need to take the socket lock since it only
* accesses socket information that is unchanging (or which changes in
* a completely predictable manner).
*/
static int get_name(struct socket *sock, struct sockaddr *uaddr,
int *uaddr_len, int peer)
{
struct sockaddr_tipc *addr = (struct sockaddr_tipc *)uaddr;
struct tipc_sock *tsock = tipc_sk(sock->sk);
memset(addr, 0, sizeof(*addr));
if (peer) {
if ((sock->state != SS_CONNECTED) &&
((peer != 2) || (sock->state != SS_DISCONNECTING)))
return -ENOTCONN;
addr->addr.id.ref = tsock->peer_name.ref;
addr->addr.id.node = tsock->peer_name.node;
} else {
addr->addr.id.ref = tsock->p->ref;
addr->addr.id.node = tipc_own_addr;
}
*uaddr_len = sizeof(*addr);
addr->addrtype = TIPC_ADDR_ID;
addr->family = AF_TIPC;
addr->scope = 0;
addr->addr.name.domain = 0;
return 0;
}
/**
* 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 pollmask value
*
* COMMENTARY:
* It appears that the usual socket locking mechanisms are not useful here
* since the pollmask info is potentially out-of-date the moment this routine
* exits. TCP and other protocols seem to rely on higher level poll routines
* to handle any preventable race conditions, so TIPC will do the same ...
*
* TIPC sets the returned events as follows:
*
* socket state flags set
* ------------ ---------
* unconnected no read flags
* no write flags
*
* connecting POLLIN/POLLRDNORM if ACK/NACK in rx queue
* no write flags
*
* connected POLLIN/POLLRDNORM if data in rx queue
* POLLOUT if port is not congested
*
* disconnecting POLLIN/POLLRDNORM/POLLHUP
* no write flags
*
* listening POLLIN if SYN in rx queue
* no write flags
*
* ready POLLIN/POLLRDNORM if data in rx queue
* [connectionless] POLLOUT (since port cannot be congested)
*
* IMPORTANT: The fact that a read or write operation is indicated does NOT
* imply that the operation will succeed, merely that it should be performed
* and will not block.
*/
static unsigned int poll(struct file *file, struct socket *sock,
poll_table *wait)
{
struct sock *sk = sock->sk;
u32 mask = 0;
poll_wait(file, sk_sleep(sk), wait);
switch ((int)sock->state) {
case SS_READY:
case SS_CONNECTED:
if (!tipc_sk_port(sk)->congested)
mask |= POLLOUT;
/* fall thru' */
case SS_CONNECTING:
case SS_LISTENING:
if (!skb_queue_empty(&sk->sk_receive_queue))
mask |= (POLLIN | POLLRDNORM);
break;
case SS_DISCONNECTING:
mask = (POLLIN | POLLRDNORM | POLLHUP);
break;
}
return mask;
}
/**
* 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 (!m->msg_iovlen || (m->msg_iov[0].iov_len < sizeof(hdr)))
return -EMSGSIZE;
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: if NULL, indicates that socket lock is already held
* @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 sock *sk = sock->sk;
struct tipc_port *tport = tipc_sk_port(sk);
struct sockaddr_tipc *dest = (struct sockaddr_tipc *)m->msg_name;
int needs_conn;
long timeout_val;
int res = -EINVAL;
if (unlikely(!dest))
return -EDESTADDRREQ;
if (unlikely((m->msg_namelen < sizeof(*dest)) ||
(dest->family != AF_TIPC)))
return -EINVAL;
if ((total_len > TIPC_MAX_USER_MSG_SIZE) ||
(m->msg_iovlen > (unsigned)INT_MAX))
return -EMSGSIZE;
if (iocb)
lock_sock(sk);
needs_conn = (sock->state != SS_READY);
if (unlikely(needs_conn)) {
if (sock->state == SS_LISTENING) {
res = -EPIPE;
goto exit;
}
if (sock->state != SS_UNCONNECTED) {
res = -EISCONN;
goto exit;
}
if ((tport->published) ||
((sock->type == SOCK_STREAM) && (total_len != 0))) {
res = -EOPNOTSUPP;
goto exit;
}
if (dest->addrtype == TIPC_ADDR_NAME) {
tport->conn_type = dest->addr.name.name.type;
tport->conn_instance = dest->addr.name.name.instance;
}
/* Abort any pending connection attempts (very unlikely) */
reject_rx_queue(sk);
}
timeout_val = sock_sndtimeo(sk, m->msg_flags & MSG_DONTWAIT);
do {
if (dest->addrtype == TIPC_ADDR_NAME) {
res = dest_name_check(dest, m);
if (res)
break;
res = tipc_send2name(tport->ref,
&dest->addr.name.name,
dest->addr.name.domain,
m->msg_iovlen,
m->msg_iov,
total_len);
} else if (dest->addrtype == TIPC_ADDR_ID) {
res = tipc_send2port(tport->ref,
&dest->addr.id,
m->msg_iovlen,
m->msg_iov,
total_len);
} else if (dest->addrtype == TIPC_ADDR_MCAST) {
if (needs_conn) {
res = -EOPNOTSUPP;
break;
}
res = dest_name_check(dest, m);
if (res)
break;
res = tipc_multicast(tport->ref,
&dest->addr.nameseq,
m->msg_iovlen,
m->msg_iov,
total_len);
}
if (likely(res != -ELINKCONG)) {
if (needs_conn && (res >= 0))
sock->state = SS_CONNECTING;
break;
}
if (timeout_val <= 0L) {
res = timeout_val ? timeout_val : -EWOULDBLOCK;
break;
}
release_sock(sk);
timeout_val = wait_event_interruptible_timeout(*sk_sleep(sk),
!tport->congested, timeout_val);
lock_sock(sk);
} while (1);
exit:
if (iocb)
release_sock(sk);
return res;
}
/**
* send_packet - send a connection-oriented message
* @iocb: if NULL, indicates that socket lock is already held
* @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 sock *sk = sock->sk;
struct tipc_port *tport = tipc_sk_port(sk);
struct sockaddr_tipc *dest = (struct sockaddr_tipc *)m->msg_name;
long timeout_val;
int res;
/* Handle implied connection establishment */
if (unlikely(dest))
return send_msg(iocb, sock, m, total_len);
if ((total_len > TIPC_MAX_USER_MSG_SIZE) ||
(m->msg_iovlen > (unsigned)INT_MAX))
return -EMSGSIZE;
if (iocb)
lock_sock(sk);
timeout_val = sock_sndtimeo(sk, m->msg_flags & MSG_DONTWAIT);
do {
if (unlikely(sock->state != SS_CONNECTED)) {
if (sock->state == SS_DISCONNECTING)
res = -EPIPE;
else
res = -ENOTCONN;
break;
}
res = tipc_send(tport->ref, m->msg_iovlen, m->msg_iov,
total_len);
if (likely(res != -ELINKCONG))
break;
if (timeout_val <= 0L) {
res = timeout_val ? timeout_val : -EWOULDBLOCK;
break;
}
release_sock(sk);
timeout_val = wait_event_interruptible_timeout(*sk_sleep(sk),
(!tport->congested || !tport->connected), timeout_val);
lock_sock(sk);
} while (1);
if (iocb)
release_sock(sk);
return res;
}
/**
* 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 sock *sk = sock->sk;
struct tipc_port *tport = tipc_sk_port(sk);
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;
lock_sock(sk);
/* Handle special cases where there is no connection */
if (unlikely(sock->state != SS_CONNECTED)) {
if (sock->state == SS_UNCONNECTED) {
res = send_packet(NULL, sock, m, total_len);
goto exit;
} else if (sock->state == SS_DISCONNECTING) {
res = -EPIPE;
goto exit;
} else {
res = -ENOTCONN;
goto exit;
}
}
if (unlikely(m->msg_name)) {
res = -EISCONN;
goto exit;
}
if ((total_len > (unsigned)INT_MAX) ||
(m->msg_iovlen > (unsigned)INT_MAX)) {
res = -EMSGSIZE;
goto exit;
}
/*
* 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;
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;
res = send_packet(NULL, sock, &my_msg, bytes_to_send);
if (res < 0) {
if (bytes_sent)
res = bytes_sent;
goto exit;
}
curr_left -= bytes_to_send;
curr_start += bytes_to_send;
bytes_sent += bytes_to_send;
}
curr_iov++;
}
res = bytes_sent;
exit:
release_sock(sk);
return res;
}
/**
* auto_connect - complete connection setup to a remote port
* @sock: socket structure
* @msg: peer's response message
*
* Returns 0 on success, errno otherwise
*/
static int auto_connect(struct socket *sock, struct tipc_msg *msg)
{
struct tipc_sock *tsock = tipc_sk(sock->sk);
if (msg_errcode(msg)) {
sock->state = SS_DISCONNECTING;
return -ECONNREFUSED;
}
tsock->peer_name.ref = msg_origport(msg);
tsock->peer_name.node = msg_orignode(msg);
tipc_connect2port(tsock->p->ref, &tsock->peer_name);
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);
res = put_cmsg(m, SOL_TIPC, TIPC_ERRINFO, 8, anc_data);
if (res)
return res;
if (anc_data[1]) {
res = put_cmsg(m, SOL_TIPC, TIPC_RETDATA, anc_data[1],
msg_data(msg));
if (res)
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);
if (res)
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 sock *sk = sock->sk;
struct tipc_port *tport = tipc_sk_port(sk);
struct sk_buff *buf;
struct tipc_msg *msg;
long timeout;
unsigned int sz;
u32 err;
int res;
/* Catch invalid receive requests */
if (unlikely(!buf_len))
return -EINVAL;
lock_sock(sk);
if (unlikely(sock->state == SS_UNCONNECTED)) {
res = -ENOTCONN;
goto exit;
}
timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
restart:
/* Look for a message in receive queue; wait if necessary */
while (skb_queue_empty(&sk->sk_receive_queue)) {
if (sock->state == SS_DISCONNECTING) {
res = -ENOTCONN;
goto exit;
}
if (timeout <= 0L) {
res = timeout ? timeout : -EWOULDBLOCK;
goto exit;
}
release_sock(sk);
timeout = wait_event_interruptible_timeout(*sk_sleep(sk),
tipc_rx_ready(sock),
timeout);
lock_sock(sk);
}
/* Look at first message in receive queue */
buf = skb_peek(&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)) {
res = auto_connect(sock, msg);
if (res)
goto exit;
}
/* Discard an empty non-errored message & try again */
if ((!sz) && (!err)) {
advance_rx_queue(sk);
goto restart;
}
/* Capture sender's address (optional) */
set_orig_addr(m, msg);
/* Capture ancillary data (optional) */
res = anc_data_recv(m, msg, tport);
if (res)
goto exit;