af_x25.c

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static int x25_create(struct socket *sock, int protocol)
{
	struct sock *sk;
	x25_cb *x25;

	if (sock->type != SOCK_SEQPACKET || protocol != 0)
		return -ESOCKTNOSUPPORT;

	if ((sk = x25_alloc_socket()) == NULL)
		return -ENOMEM;

	x25 = sk->protinfo.x25;

	sock_init_data(sock, sk);

	init_timer(&x25->timer);

	sock->ops    = &x25_proto_ops;
	sk->protocol = protocol;
	sk->backlog_rcv = x25_backlog_rcv;

	x25->t21   = sysctl_x25_call_request_timeout;
	x25->t22   = sysctl_x25_reset_request_timeout;
	x25->t23   = sysctl_x25_clear_request_timeout;
	x25->t2    = sysctl_x25_ack_holdback_timeout;
	x25->state = X25_STATE_0;

	x25->facilities.winsize_in  = X25_DEFAULT_WINDOW_SIZE;
	x25->facilities.winsize_out = X25_DEFAULT_WINDOW_SIZE;
	x25->facilities.pacsize_in  = X25_DEFAULT_PACKET_SIZE;
	x25->facilities.pacsize_out = X25_DEFAULT_PACKET_SIZE;
	x25->facilities.throughput  = X25_DEFAULT_THROUGHPUT;
	x25->facilities.reverse     = X25_DEFAULT_REVERSE;

	return 0;
}

static struct sock *x25_make_new(struct sock *osk)
{
	struct sock *sk;
	x25_cb *x25;

	if (osk->type != SOCK_SEQPACKET)
		return NULL;

	if ((sk = x25_alloc_socket()) == NULL)
		return NULL;

	x25 = sk->protinfo.x25;

	sk->type        = osk->type;
	sk->socket      = osk->socket;
	sk->priority    = osk->priority;
	sk->protocol    = osk->protocol;
	sk->rcvbuf      = osk->rcvbuf;
	sk->sndbuf      = osk->sndbuf;
	sk->debug       = osk->debug;
	sk->state       = TCP_ESTABLISHED;
	sk->sleep       = osk->sleep;
	sk->zapped      = osk->zapped;
	sk->backlog_rcv = osk->backlog_rcv;

	x25->t21        = osk->protinfo.x25->t21;
	x25->t22        = osk->protinfo.x25->t22;
	x25->t23        = osk->protinfo.x25->t23;
	x25->t2         = osk->protinfo.x25->t2;

	x25->facilities = osk->protinfo.x25->facilities;

	x25->qbitincl   = osk->protinfo.x25->qbitincl;

	init_timer(&x25->timer);

	return sk;
}

static int x25_release(struct socket *sock)
{
	struct sock *sk = sock->sk;

	if (sk == NULL) return 0;

	switch (sk->protinfo.x25->state) {

		case X25_STATE_0:
		case X25_STATE_2:
			x25_disconnect(sk, 0, 0, 0);
			x25_destroy_socket(sk);
			break;

		case X25_STATE_1:
		case X25_STATE_3:
		case X25_STATE_4:
			x25_clear_queues(sk);
			x25_write_internal(sk, X25_CLEAR_REQUEST);
			x25_start_t23timer(sk);
			sk->protinfo.x25->state = X25_STATE_2;
			sk->state               = TCP_CLOSE;
			sk->shutdown           |= SEND_SHUTDOWN;
			sk->state_change(sk);
			sk->dead                = 1;
			sk->destroy             = 1;
			break;

		default:
			break;
	}

	sock->sk   = NULL;	
	sk->socket = NULL;	/* Not used, but we should do this */

	return 0;
}

static int x25_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
	struct sock *sk = sock->sk;
	struct sockaddr_x25 *addr = (struct sockaddr_x25 *)uaddr;

	if (sk->zapped == 0)
		return -EINVAL;

	if (addr_len != sizeof(struct sockaddr_x25))
		return -EINVAL;

	if (addr->sx25_family != AF_X25)
		return -EINVAL;

	sk->protinfo.x25->source_addr = addr->sx25_addr;

	x25_insert_socket(sk);

	sk->zapped = 0;

	SOCK_DEBUG(sk, "x25_bind: socket is bound\n");

	return 0;
}

static int x25_connect(struct socket *sock, struct sockaddr *uaddr, int addr_len, int flags)
{
	struct sock *sk = sock->sk;
	struct sockaddr_x25 *addr = (struct sockaddr_x25 *)uaddr;
	struct net_device *dev;

	if (sk->state == TCP_ESTABLISHED && sock->state == SS_CONNECTING) {
		sock->state = SS_CONNECTED;
		return 0;	/* Connect completed during a ERESTARTSYS event */
	}

	if (sk->state == TCP_CLOSE && sock->state == SS_CONNECTING) {
		sock->state = SS_UNCONNECTED;
		return -ECONNREFUSED;
	}

	if (sk->state == TCP_ESTABLISHED)
		return -EISCONN;	/* No reconnect on a seqpacket socket */

	sk->state   = TCP_CLOSE;	
	sock->state = SS_UNCONNECTED;

	if (addr_len != sizeof(struct sockaddr_x25))
		return -EINVAL;

	if (addr->sx25_family != AF_X25)
		return -EINVAL;

	if ((dev = x25_get_route(&addr->sx25_addr)) == NULL)
		return -ENETUNREACH;

	if ((sk->protinfo.x25->neighbour = x25_get_neigh(dev)) == NULL)
		return -ENETUNREACH;

	x25_limit_facilities(&sk->protinfo.x25->facilities,
			     sk->protinfo.x25->neighbour);

	if ((sk->protinfo.x25->lci = x25_new_lci(sk->protinfo.x25->neighbour)) == 0)
		return -ENETUNREACH;

	if (sk->zapped)		/* Must bind first - autobinding does not work */
		return -EINVAL;

	if (strcmp(sk->protinfo.x25->source_addr.x25_addr, null_x25_address.x25_addr) == 0)
		memset(&sk->protinfo.x25->source_addr, '\0', X25_ADDR_LEN);

	sk->protinfo.x25->dest_addr = addr->sx25_addr;

	/* Move to connecting socket, start sending Connect Requests */
	sock->state   = SS_CONNECTING;
	sk->state     = TCP_SYN_SENT;

	sk->protinfo.x25->state = X25_STATE_1;

	x25_write_internal(sk, X25_CALL_REQUEST);

	x25_start_heartbeat(sk);
	x25_start_t21timer(sk);

	/* Now the loop */
	if (sk->state != TCP_ESTABLISHED && (flags & O_NONBLOCK))
		return -EINPROGRESS;

	cli();	/* To avoid races on the sleep */

	/*
	 * A Clear Request or timeout or failed routing will go to closed.
	 */
	while (sk->state == TCP_SYN_SENT) {
		interruptible_sleep_on(sk->sleep);
		if (signal_pending(current)) {
			sti();
			return -ERESTARTSYS;
		}
	}

	if (sk->state != TCP_ESTABLISHED) {
		sti();
		sock->state = SS_UNCONNECTED;
		return sock_error(sk);	/* Always set at this point */
	}

	sock->state = SS_CONNECTED;

	sti();

	return 0;
}
	
static int x25_accept(struct socket *sock, struct socket *newsock, int flags)
{
	struct sock *sk;
	struct sock *newsk;
	struct sk_buff *skb;

	if ((sk = sock->sk) == NULL)
		return -EINVAL;

	if (sk->type != SOCK_SEQPACKET)
		return -EOPNOTSUPP;

	if (sk->state != TCP_LISTEN)
		return -EINVAL;

	/*
	 *	The write queue this time is holding sockets ready to use
	 *	hooked into the CALL INDICATION we saved
	 */
	do {
		cli();
		if ((skb = skb_dequeue(&sk->receive_queue)) == NULL) {
			if (flags & O_NONBLOCK) {
				sti();
				return -EWOULDBLOCK;
			}
			interruptible_sleep_on(sk->sleep);
			if (signal_pending(current)) {
				sti();
				return -ERESTARTSYS;
			}
		}
	} while (skb == NULL);

	newsk = skb->sk;
	newsk->pair = NULL;
	newsk->socket = newsock;
	newsk->sleep = &newsock->wait;
	sti();

	/* Now attach up the new socket */
	skb->sk = NULL;
	kfree_skb(skb);
	sk->ack_backlog--;
	newsock->sk = newsk;
	newsock->state = SS_CONNECTED;

	return 0;
}

static int x25_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
{
	struct sockaddr_x25 *sx25 = (struct sockaddr_x25 *)uaddr;
	struct sock *sk = sock->sk;

	if (peer != 0) {
		if (sk->state != TCP_ESTABLISHED)
			return -ENOTCONN;
		sx25->sx25_addr   = sk->protinfo.x25->dest_addr;
	} else {
		sx25->sx25_addr   = sk->protinfo.x25->source_addr;
	}

	sx25->sx25_family = AF_X25;
	*uaddr_len = sizeof(struct sockaddr_x25);

	return 0;
}
 
int x25_rx_call_request(struct sk_buff *skb, struct x25_neigh *neigh, unsigned int lci)
{
	struct sock *sk;
	struct sock *make;
	x25_address source_addr, dest_addr;
	struct x25_facilities facilities;
	int len;

	/*
	 *	Remove the LCI and frame type.
	 */
	skb_pull(skb, X25_STD_MIN_LEN);

	/*
	 *	Extract the X.25 addresses and convert them to ASCII strings,
	 *	and remove them.
	 */
	skb_pull(skb, x25_addr_ntoa(skb->data, &source_addr, &dest_addr));

	/*
	 *	Find a listener for the particular address.
	 */
	sk = x25_find_listener(&source_addr);

	/*
	 *	We can't accept the Call Request.
	 */
	if (sk == NULL || sk->ack_backlog == sk->max_ack_backlog) {
		x25_transmit_clear_request(neigh, lci, 0x01);
		return 0;
	}

	/*
	 *	Try to reach a compromise on the requested facilities.
	 */
	if ((len = x25_negotiate_facilities(skb, sk, &facilities)) == -1) {
		x25_transmit_clear_request(neigh, lci, 0x01);
		return 0;
	}

	/*
	 * current neighbour/link might impose additional limits
	 * on certain facilties
	 */

	x25_limit_facilities(&facilities,neigh);

	/*
	 *	Try to create a new socket.
	 */
	if ((make = x25_make_new(sk)) == NULL) {
		x25_transmit_clear_request(neigh, lci, 0x01);
		return 0;
	}

	/*
	 *	Remove the facilities, leaving any Call User Data.
	 */
	skb_pull(skb, len);

	skb->sk     = make;
	make->state = TCP_ESTABLISHED;

	make->protinfo.x25->lci           = lci;
	make->protinfo.x25->dest_addr     = dest_addr;
	make->protinfo.x25->source_addr   = source_addr;
	make->protinfo.x25->neighbour     = neigh;
	make->protinfo.x25->facilities    = facilities;
	make->protinfo.x25->vc_facil_mask = sk->protinfo.x25->vc_facil_mask;

	x25_write_internal(make, X25_CALL_ACCEPTED);

	/*
	 *	Incoming Call User Data.
	 */
	if (skb->len >= 0) {
		memcpy(make->protinfo.x25->calluserdata.cuddata, skb->data, skb->len);
		make->protinfo.x25->calluserdata.cudlength = skb->len;
	}

	make->protinfo.x25->state = X25_STATE_3;

	sk->ack_backlog++;
	make->pair = sk;

	x25_insert_socket(make);

	skb_queue_head(&sk->receive_queue, skb);

	x25_start_heartbeat(make);

	if (!sk->dead)
		sk->data_ready(sk, skb->len);

	return 1;
}

static int x25_sendmsg(struct socket *sock, struct msghdr *msg, int len, struct scm_cookie *scm)
{
	struct sock *sk = sock->sk;
	struct sockaddr_x25 *usx25 = (struct sockaddr_x25 *)msg->msg_name;
	int err;
	struct sockaddr_x25 sx25;
	struct sk_buff *skb;
	unsigned char *asmptr;
	int size, qbit = 0;

	if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_OOB | MSG_EOR))
		return -EINVAL;

	/* we currently don't support segmented records at the user interface */
	if (!(msg->msg_flags & (MSG_EOR|MSG_OOB)))
		return -EINVAL;

	if (sk->zapped)
		return -EADDRNOTAVAIL;

	if (sk->shutdown & SEND_SHUTDOWN) {
		send_sig(SIGPIPE, current, 0);
		return -EPIPE;
	}

	if (sk->protinfo.x25->neighbour == NULL)
		return -ENETUNREACH;

	if (usx25 != NULL) {
		if (msg->msg_namelen < sizeof(sx25))
			return -EINVAL;
		sx25 = *usx25;
		if (strcmp(sk->protinfo.x25->dest_addr.x25_addr, sx25.sx25_addr.x25_addr) != 0)
			return -EISCONN;
		if (sx25.sx25_family != AF_X25)
			return -EINVAL;
	} else {
		/*
		 *	FIXME 1003.1g - if the socket is like this because
		 *	it has become closed (not started closed) we ought
		 *	to SIGPIPE, EPIPE;
		 */
		if (sk->state != TCP_ESTABLISHED)
			return -ENOTCONN;

		sx25.sx25_family = AF_X25;
		sx25.sx25_addr   = sk->protinfo.x25->dest_addr;
	}

	SOCK_DEBUG(sk, "x25_sendmsg: sendto: Addresses built.\n");

	/* Build a packet */
	SOCK_DEBUG(sk, "x25_sendmsg: sendto: building packet.\n");

	if ((msg->msg_flags & MSG_OOB) && len > 32)
		len = 32;

	size = len + X25_MAX_L2_LEN + X25_EXT_MIN_LEN;

	if ((skb = sock_alloc_send_skb(sk, size, 0, msg->msg_flags & MSG_DONTWAIT, &err)) == NULL)
		return err;
	X25_SKB_CB(skb)->flags = msg->msg_flags;

	skb_reserve(skb, X25_MAX_L2_LEN + X25_EXT_MIN_LEN);

	/*
	 *	Put the data on the end