af_llc.c

linux 内核源代码

 *	@sock: Socket which connections arrive on.
 *	@newsock: Socket to move incoming connection to.
 *	@flags: User specified operational flags.
 *
 *	Accept a new incoming connection.
 *	Returns 0 upon success, negative otherwise.
 */
static int llc_ui_accept(struct socket *sock, struct socket *newsock, int flags)
{
	struct sock *sk = sock->sk, *newsk;
	struct llc_sock *llc, *newllc;
	struct sk_buff *skb;
	int rc = -EOPNOTSUPP;

	dprintk("%s: accepting on %02X\n", __FUNCTION__,
		llc_sk(sk)->laddr.lsap);
	lock_sock(sk);
	if (unlikely(sk->sk_type != SOCK_STREAM))
		goto out;
	rc = -EINVAL;
	if (unlikely(sock->state != SS_UNCONNECTED ||
		     sk->sk_state != TCP_LISTEN))
		goto out;
	/* wait for a connection to arrive. */
	if (skb_queue_empty(&sk->sk_receive_queue)) {
		rc = llc_wait_data(sk, sk->sk_rcvtimeo);
		if (rc)
			goto out;
	}
	dprintk("%s: got a new connection on %02X\n", __FUNCTION__,
		llc_sk(sk)->laddr.lsap);
	skb = skb_dequeue(&sk->sk_receive_queue);
	rc = -EINVAL;
	if (!skb->sk)
		goto frees;
	rc = 0;
	newsk = skb->sk;
	/* attach connection to a new socket. */
	llc_ui_sk_init(newsock, newsk);
	sock_reset_flag(newsk, SOCK_ZAPPED);
	newsk->sk_state		= TCP_ESTABLISHED;
	newsock->state		= SS_CONNECTED;
	llc			= llc_sk(sk);
	newllc			= llc_sk(newsk);
	memcpy(&newllc->addr, &llc->addr, sizeof(newllc->addr));
	newllc->link = llc_ui_next_link_no(newllc->laddr.lsap);

	/* put original socket back into a clean listen state. */
	sk->sk_state = TCP_LISTEN;
	sk->sk_ack_backlog--;
	dprintk("%s: ok success on %02X, client on %02X\n", __FUNCTION__,
		llc_sk(sk)->addr.sllc_sap, newllc->daddr.lsap);
frees:
	kfree_skb(skb);
out:
	release_sock(sk);
	return rc;
}

/**
 *	llc_ui_recvmsg - copy received data to the socket user.
 *	@sock: Socket to copy data from.
 *	@msg: Various user space related information.
 *	@len: Size of user buffer.
 *	@flags: User specified flags.
 *
 *	Copy received data to the socket user.
 *	Returns non-negative upon success, negative otherwise.
 */
static int llc_ui_recvmsg(struct kiocb *iocb, struct socket *sock,
			  struct msghdr *msg, size_t len, int flags)
{
	struct sockaddr_llc *uaddr = (struct sockaddr_llc *)msg->msg_name;
	const int nonblock = flags & MSG_DONTWAIT;
	struct sk_buff *skb = NULL;
	struct sock *sk = sock->sk;
	struct llc_sock *llc = llc_sk(sk);
	size_t copied = 0;
	u32 peek_seq = 0;
	u32 *seq;
	unsigned long used;
	int target;	/* Read at least this many bytes */
	long timeo;

	lock_sock(sk);
	copied = -ENOTCONN;
	if (unlikely(sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_LISTEN))
		goto out;

	timeo = sock_rcvtimeo(sk, nonblock);

	seq = &llc->copied_seq;
	if (flags & MSG_PEEK) {
		peek_seq = llc->copied_seq;
		seq = &peek_seq;
	}

	target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
	copied = 0;

	do {
		u32 offset;

		/*
		 * We need to check signals first, to get correct SIGURG
		 * handling. FIXME: Need to check this doesn't impact 1003.1g
		 * and move it down to the bottom of the loop
		 */
		if (signal_pending(current)) {
			if (copied)
				break;
			copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
			break;
		}

		/* Next get a buffer. */

		skb = skb_peek(&sk->sk_receive_queue);
		if (skb) {
			offset = *seq;
			goto found_ok_skb;
		}
		/* Well, if we have backlog, try to process it now yet. */

		if (copied >= target && !sk->sk_backlog.tail)
			break;

		if (copied) {
			if (sk->sk_err ||
			    sk->sk_state == TCP_CLOSE ||
			    (sk->sk_shutdown & RCV_SHUTDOWN) ||
			    !timeo ||
			    (flags & MSG_PEEK))
				break;
		} else {
			if (sock_flag(sk, SOCK_DONE))
				break;

			if (sk->sk_err) {
				copied = sock_error(sk);
				break;
			}
			if (sk->sk_shutdown & RCV_SHUTDOWN)
				break;

			if (sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_CLOSE) {
				if (!sock_flag(sk, SOCK_DONE)) {
					/*
					 * This occurs when user tries to read
					 * from never connected socket.
					 */
					copied = -ENOTCONN;
					break;
				}
				break;
			}
			if (!timeo) {
				copied = -EAGAIN;
				break;
			}
		}

		if (copied >= target) { /* Do not sleep, just process backlog. */
			release_sock(sk);
			lock_sock(sk);
		} else
			sk_wait_data(sk, &timeo);

		if ((flags & MSG_PEEK) && peek_seq != llc->copied_seq) {
			if (net_ratelimit())
				printk(KERN_DEBUG "LLC(%s:%d): Application "
						  "bug, race in MSG_PEEK.\n",
				       current->comm, task_pid_nr(current));
			peek_seq = llc->copied_seq;
		}
		continue;
	found_ok_skb:
		/* Ok so how much can we use? */
		used = skb->len - offset;
		if (len < used)
			used = len;

		if (!(flags & MSG_TRUNC)) {
			int rc = skb_copy_datagram_iovec(skb, offset,
							 msg->msg_iov, used);
			if (rc) {
				/* Exception. Bailout! */
				if (!copied)
					copied = -EFAULT;
				break;
			}
		}

		*seq += used;
		copied += used;
		len -= used;

		if (!(flags & MSG_PEEK)) {
			sk_eat_skb(sk, skb, 0);
			*seq = 0;
		}

		/* For non stream protcols we get one packet per recvmsg call */
		if (sk->sk_type != SOCK_STREAM)
			goto copy_uaddr;

		/* Partial read */
		if (used + offset < skb->len)
			continue;
	} while (len > 0);

out:
	release_sock(sk);
	return copied;
copy_uaddr:
	if (uaddr != NULL && skb != NULL) {
		memcpy(uaddr, llc_ui_skb_cb(skb), sizeof(*uaddr));
		msg->msg_namelen = sizeof(*uaddr);
	}
	goto out;
}

/**
 *	llc_ui_sendmsg - Transmit data provided by the socket user.
 *	@sock: Socket to transmit data from.
 *	@msg: Various user related information.
 *	@len: Length of data to transmit.
 *
 *	Transmit data provided by the socket user.
 *	Returns non-negative upon success, negative otherwise.
 */
static int llc_ui_sendmsg(struct kiocb *iocb, struct socket *sock,
			  struct msghdr *msg, size_t len)
{
	struct sock *sk = sock->sk;
	struct llc_sock *llc = llc_sk(sk);
	struct sockaddr_llc *addr = (struct sockaddr_llc *)msg->msg_name;
	int flags = msg->msg_flags;
	int noblock = flags & MSG_DONTWAIT;
	struct sk_buff *skb;
	size_t size = 0;
	int rc = -EINVAL, copied = 0, hdrlen;

	dprintk("%s: sending from %02X to %02X\n", __FUNCTION__,
		llc->laddr.lsap, llc->daddr.lsap);
	lock_sock(sk);
	if (addr) {
		if (msg->msg_namelen < sizeof(*addr))
			goto release;
	} else {
		if (llc_ui_addr_null(&llc->addr))
			goto release;
		addr = &llc->addr;
	}
	/* must bind connection to sap if user hasn't done it. */
	if (sock_flag(sk, SOCK_ZAPPED)) {
		/* bind to sap with null dev, exclusive. */
		rc = llc_ui_autobind(sock, addr);
		if (rc)
			goto release;
	}
	hdrlen = llc->dev->hard_header_len + llc_ui_header_len(sk, addr);
	size = hdrlen + len;
	if (size > llc->dev->mtu)
		size = llc->dev->mtu;
	copied = size - hdrlen;
	release_sock(sk);
	skb = sock_alloc_send_skb(sk, size, noblock, &rc);
	lock_sock(sk);
	if (!skb)
		goto release;
	skb->dev      = llc->dev;
	skb->protocol = llc_proto_type(addr->sllc_arphrd);
	skb_reserve(skb, hdrlen);
	rc = memcpy_fromiovec(skb_put(skb, copied), msg->msg_iov, copied);
	if (rc)
		goto out;
	if (sk->sk_type == SOCK_DGRAM || addr->sllc_ua) {
		llc_build_and_send_ui_pkt(llc->sap, skb, addr->sllc_mac,
					  addr->sllc_sap);
		goto out;
	}
	if (addr->sllc_test) {
		llc_build_and_send_test_pkt(llc->sap, skb, addr->sllc_mac,
					    addr->sllc_sap);
		goto out;
	}
	if (addr->sllc_xid) {
		llc_build_and_send_xid_pkt(llc->sap, skb, addr->sllc_mac,
					   addr->sllc_sap);
		goto out;
	}
	rc = -ENOPROTOOPT;
	if (!(sk->sk_type == SOCK_STREAM && !addr->sllc_ua))
		goto out;
	rc = llc_ui_send_data(sk, skb, noblock);
out:
	if (rc) {
		kfree_skb(skb);
release:
		dprintk("%s: failed sending from %02X to %02X: %d\n",
			__FUNCTION__, llc->laddr.lsap, llc->daddr.lsap, rc);
	}
	release_sock(sk);
	return rc ? : copied;
}

/**
 *	llc_ui_getname - return the address info of a socket
 *	@sock: Socket to get address of.
 *	@uaddr: Address structure to return information.
 *	@uaddrlen: Length of address structure.
 *	@peer: Does user want local or remote address information.
 *
 *	Return the address information of a socket.
 */
static int llc_ui_getname(struct socket *sock, struct sockaddr *uaddr,
			  int *uaddrlen, int peer)
{
	struct sockaddr_llc sllc;
	struct sock *sk = sock->sk;
	struct llc_sock *llc = llc_sk(sk);
	int rc = 0;

	lock_sock(sk);
	if (sock_flag(sk, SOCK_ZAPPED))
		goto out;
	*uaddrlen = sizeof(sllc);
	memset(uaddr, 0, *uaddrlen);
	if (peer) {
		rc = -ENOTCONN;
		if (sk->sk_state != TCP_ESTABLISHED)
			goto out;
		if(llc->dev)
			sllc.sllc_arphrd = llc->dev->type;
		sllc.sllc_sap = llc->daddr.lsap;
		memcpy(&sllc.sllc_mac, &llc->daddr.mac, IFHWADDRLEN);
	} else {
		rc = -EINVAL;
		if (!llc->sap)
			goto out;
		sllc.sllc_sap = llc->sap->laddr.lsap;

		if (llc->dev) {
			sllc.sllc_arphrd = llc->dev->type;
			memcpy(&sllc.sllc_mac, &llc->dev->dev_addr,
			       IFHWADDRLEN);
		}
	}
	rc = 0;
	sllc.sllc_family = AF_LLC;
	memcpy(uaddr, &sllc, sizeof(sllc));
out:
	release_sock(sk);
	return rc;
}

/**
 *	llc_ui_ioctl - io controls for PF_LLC
 *	@sock: Socket to get/set info
 *	@cmd: command
 *	@arg: optional argument for cmd
 *
 *	get/set info on llc sockets
 */
static int llc_ui_ioctl(struct socket *sock, unsigned int cmd,
			unsigned long arg)
{
	return -ENOIOCTLCMD;
}

/**
 *	llc_ui_setsockopt - set various connection specific parameters.
 *	@sock: Socket to set options on.
 *	@level: Socket level user is requesting operations on.
 *	@optname: Operation name.
 *	@optval User provided operation data.
 *	@optlen: Length of optval.
 *
 *	Set various connection specific parameters.
 */
static int llc_ui_setsockopt(struct socket *sock, int level, int optname,
			     char __user *optval, int optlen)
{
	struct sock *sk = sock->sk;
	struct llc_sock *llc = llc_sk(sk);
	int rc = -EINVAL, opt;

	lock_sock(sk);
	if (unlikely(level != SOL_LLC || optlen != sizeof(int)))
		goto out;
	rc = get_user(opt, (int __user *)optval);
	if (rc)
		goto out;
	rc = -EINVAL;
	switch (optname) {
	case LLC_OPT_RETRY:
		if (opt > LLC_OPT_MAX_RETRY)
			goto out;
		llc->n2 = opt;
		break;
	case LLC_OPT_SIZE:
		if (opt > LLC_OPT_MAX_SIZE)
			goto out;
		llc->n1 = opt;
		break;
	case LLC_OPT_ACK_TMR_EXP:
		if (opt > LLC_OPT_MAX_ACK_TMR_EXP)
			goto out;
		llc->ack_timer.expire = opt * HZ;
		break;
	case LLC_OPT_P_TMR_EXP:
		if (opt > LLC_OPT_MAX_P_TMR_EXP)
			goto out;
		llc->pf_cycle_timer.expire = opt * HZ;
		break;
	case LLC_OPT_REJ_TMR_EXP:
		if (opt > LLC_OPT_MAX_REJ_TMR_EXP)
			goto out;
		llc->rej_sent_timer.expire = opt * HZ;
		break;
	case LLC_OPT_BUSY_TMR_EXP:
		if (opt > LLC_OPT_MAX_BUSY_TMR_EXP)
			goto out;
		llc->busy_state_timer.expire = opt * HZ;
		break;
	case LLC_OPT_TX_WIN:
		if (opt > LLC_OPT_MAX_WIN)
			goto out;
		llc->k = opt;
		break;
	case LLC_OPT_RX_WIN:
		if (opt > LLC_OPT_MAX_WIN)
			goto out;
		llc->rw = opt;
		break;
	default:
		rc = -ENOPROTOOPT;
		goto out;
	}
	rc = 0;
out:
	release_sock(sk);
	return rc;
}

/**
 *	llc_ui_getsockopt - get connection specific socket info
 *	@sock: Socket to get information from.
 *	@level: Socket level user is requesting operations on.
 *	@optname: Operation name.
 *	@optval: Variable to return operation data in.
 *	@optlen: Length of optval.
 *
 *	Get connection specific socket information.
 */
static int llc_ui_getsockopt(struct socket *sock, int level, int optname,
			     char __user *optval, int __user *optlen)
{
	struct sock *sk = sock->sk;
	struct llc_sock *llc = llc_sk(sk);
	int val = 0, len = 0, rc = -EINVAL;

	lock_sock(sk);
	if (unlikely(level != SOL_LLC))
		goto out;
	rc = get_user(len, optlen);
	if (rc)
		goto out;
	rc = -EINVAL;
	if (len != sizeof(int))
		goto out;
	switch (optname) {
	case LLC_OPT_RETRY:
		val = llc->n2;					break;
	case LLC_OPT_SIZE:
		val = llc->n1;					break;
	case LLC_OPT_ACK_TMR_EXP:
		val = llc->ack_timer.expire / HZ;		break;
	case LLC_OPT_P_TMR_EXP:
		val = llc->pf_cycle_timer.expire / HZ;		break;
	case LLC_OPT_REJ_TMR_EXP:
		val = llc->rej_sent_timer.expire / HZ;		break;
	case LLC_OPT_BUSY_TMR_EXP:
		val = llc->busy_state_timer.expire / HZ;	break;
	case LLC_OPT_TX_WIN:
		val = llc->k;				break;
	case LLC_OPT_RX_WIN:
		val = llc->rw;				break;
	default:
		rc = -ENOPROTOOPT;
		goto out;
	}
	rc = 0;
	if (put_user(len, optlen) || copy_to_user(optval, &val, len))
		rc = -EFAULT;
out:
	release_sock(sk);
	return rc;
}

static struct net_proto_family llc_ui_family_ops = {
	.family = PF_LLC,
	.create = llc_ui_create,
	.owner	= THIS_MODULE,
};

static const struct proto_ops llc_ui_ops = {
	.family	     = PF_LLC,
	.owner       = THIS_MODULE,
	.release     = llc_ui_release,
	.bind	     = llc_ui_bind,
	.connect     = llc_ui_connect,
	.socketpair  = sock_no_socketpair,
	.accept      = llc_ui_accept,
	.getname     = llc_ui_getname,
	.poll	     = datagram_poll,
	.ioctl       = llc_ui_ioctl,
	.listen      = llc_ui_listen,
	.shutdown    = llc_ui_shutdown,
	.setsockopt  = llc_ui_setsockopt,
	.getsockopt  = llc_ui_getsockopt,
	.sendmsg     = llc_ui_sendmsg,
	.recvmsg     = llc_ui_recvmsg,
	.mmap	     = sock_no_mmap,
	.sendpage    = sock_no_sendpage,
};

static char llc_proc_err_msg[] __initdata =
	KERN_CRIT "LLC: Unable to register the proc_fs entries\n";
static char llc_sysctl_err_msg[] __initdata =
	KERN_CRIT "LLC: Unable to register the sysctl entries\n";
static char llc_sock_err_msg[] __initdata =
	KERN_CRIT "LLC: Unable to register the network family\n";

static int __init llc2_init(void)
{
	int rc = proto_register(&llc_proto, 0);

	if (rc != 0)
		goto out;

	llc_build_offset_table();
	llc_station_init();
	llc_ui_sap_last_autoport = LLC_SAP_DYN_START;
	rc = llc_proc_init();
	if (rc != 0) {
		printk(llc_proc_err_msg);
		goto out_unregister_llc_proto;
	}
	rc = llc_sysctl_init();
	if (rc) {
		printk(llc_sysctl_err_msg);
		goto out_proc;
	}
	rc = sock_register(&llc_ui_family_ops);
	if (rc) {
		printk(llc_sock_err_msg);
		goto out_sysctl;
	}
	llc_add_pack(LLC_DEST_SAP, llc_sap_handler);
	llc_add_pack(LLC_DEST_CONN, llc_conn_handler);
out:
	return rc;
out_sysctl:
	llc_sysctl_exit();
out_proc:
	llc_proc_exit();
out_unregister_llc_proto:
	proto_unregister(&llc_proto);
	goto out;
}

static void __exit llc2_exit(void)
{
	llc_station_exit();
	llc_remove_pack(LLC_DEST_SAP);
	llc_remove_pack(LLC_DEST_CONN);
	sock_unregister(PF_LLC);
	llc_proc_exit();
	llc_sysctl_exit();
	proto_unregister(&llc_proto);
}

module_init(llc2_init);
module_exit(llc2_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Procom 1997, Jay Schullist 2001, Arnaldo C. Melo 2001-2003");
MODULE_DESCRIPTION("IEEE 802.2 PF_LLC support");
MODULE_ALIAS_NETPROTO(PF_LLC);