socket.c

linux 内核源代码

		}
	} 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(sock->sk->sk_net, 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);
}