// SPDX-License-Identifier: GPL-2.0

  /* net/atm/svc.c - ATM SVC sockets */
  
  /* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA */

  #define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__

  
  #include <linux/string.h>
  #include <linux/net.h>		/* struct socket, struct proto_ops */
  #include <linux/errno.h>	/* error codes */
  #include <linux/kernel.h>	/* printk */
  #include <linux/skbuff.h>
  #include <linux/wait.h>

  #include <linux/sched/signal.h>

  #include <linux/fcntl.h>	/* O_NONBLOCK */
  #include <linux/init.h>
  #include <linux/atm.h>		/* ATM stuff */
  #include <linux/atmsap.h>
  #include <linux/atmsvc.h>
  #include <linux/atmdev.h>
  #include <linux/bitops.h>
  #include <net/sock.h>		/* for sock_no_* */

  #include <linux/uaccess.h>

  #include <linux/export.h>

  
  #include "resources.h"
  #include "common.h"		/* common for PVCs and SVCs */
  #include "signaling.h"
  #include "addr.h"

  static int svc_create(struct net *net, struct socket *sock, int protocol,
  		      int kern);

  /*
   * Note: since all this is still nicely synchronized with the signaling demon,
   *       there's no need to protect sleep loops with clis. If signaling is
   *       moved into the kernel, that would change.
   */

  static int svc_shutdown(struct socket *sock, int how)

  {
  	return 0;
  }

  static void svc_disconnect(struct atm_vcc *vcc)
  {
  	DEFINE_WAIT(wait);
  	struct sk_buff *skb;
  	struct sock *sk = sk_atm(vcc);

  	pr_debug("%p
  ", vcc);
  	if (test_bit(ATM_VF_REGIS, &vcc->flags)) {

  		sigd_enq(vcc, as_close, NULL, NULL, NULL);

  		for (;;) {
  			prepare_to_wait(sk_sleep(sk), &wait, TASK_UNINTERRUPTIBLE);
  			if (test_bit(ATM_VF_RELEASED, &vcc->flags) || !sigd)
  				break;

  			schedule();

  		}

  		finish_wait(sk_sleep(sk), &wait);

  	}
  	/* beware - socket is still in use by atmsigd until the last
  	   as_indicate has been answered */
  	while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
  		atm_return(vcc, skb->truesize);

  		pr_debug("LISTEN REL
  ");

  		sigd_enq2(NULL, as_reject, vcc, NULL, NULL, &vcc->qos, 0);

  		dev_kfree_skb(skb);
  	}
  	clear_bit(ATM_VF_REGIS, &vcc->flags);
  	/* ... may retry later */
  }

  static int svc_release(struct socket *sock)
  {
  	struct sock *sk = sock->sk;
  	struct atm_vcc *vcc;

  	if (sk) {

  		vcc = ATM_SD(sock);

  		pr_debug("%p
  ", vcc);

  		clear_bit(ATM_VF_READY, &vcc->flags);

  		/*
  		 * VCC pointer is used as a reference,
  		 * so we must not free it (thereby subjecting it to re-use)
  		 * before all pending connections are closed
  		 */

  		svc_disconnect(vcc);
  		vcc_release(sock);
  	}
  	return 0;
  }

  static int svc_bind(struct socket *sock, struct sockaddr *sockaddr,
  		    int sockaddr_len)

  {
  	DEFINE_WAIT(wait);
  	struct sock *sk = sock->sk;
  	struct sockaddr_atmsvc *addr;
  	struct atm_vcc *vcc;
  	int error;
  
  	if (sockaddr_len != sizeof(struct sockaddr_atmsvc))
  		return -EINVAL;
  	lock_sock(sk);
  	if (sock->state == SS_CONNECTED) {
  		error = -EISCONN;
  		goto out;
  	}
  	if (sock->state != SS_UNCONNECTED) {
  		error = -EINVAL;
  		goto out;
  	}
  	vcc = ATM_SD(sock);

  	addr = (struct sockaddr_atmsvc *) sockaddr;
  	if (addr->sas_family != AF_ATMSVC) {
  		error = -EAFNOSUPPORT;
  		goto out;
  	}

  	clear_bit(ATM_VF_BOUND, &vcc->flags);

  	    /* failing rebind will kill old binding */
  	/* @@@ check memory (de)allocation on rebind */

  	if (!test_bit(ATM_VF_HASQOS, &vcc->flags)) {

  		error = -EBADFD;
  		goto out;
  	}
  	vcc->local = *addr;
  	set_bit(ATM_VF_WAITING, &vcc->flags);

  	sigd_enq(vcc, as_bind, NULL, NULL, &vcc->local);

  	for (;;) {

  		prepare_to_wait(sk_sleep(sk), &wait, TASK_UNINTERRUPTIBLE);

  		if (!test_bit(ATM_VF_WAITING, &vcc->flags) || !sigd)
  			break;
  		schedule();

  	}

  	finish_wait(sk_sleep(sk), &wait);

  	clear_bit(ATM_VF_REGIS, &vcc->flags); /* doesn't count */

  	if (!sigd) {
  		error = -EUNATCH;
  		goto out;
  	}

  	if (!sk->sk_err)

  		set_bit(ATM_VF_BOUND, &vcc->flags);

  	error = -sk->sk_err;
  out:
  	release_sock(sk);
  	return error;
  }

  static int svc_connect(struct socket *sock, struct sockaddr *sockaddr,
  		       int sockaddr_len, int flags)

  {
  	DEFINE_WAIT(wait);
  	struct sock *sk = sock->sk;
  	struct sockaddr_atmsvc *addr;
  	struct atm_vcc *vcc = ATM_SD(sock);
  	int error;

  	pr_debug("%p
  ", vcc);

  	lock_sock(sk);
  	if (sockaddr_len != sizeof(struct sockaddr_atmsvc)) {
  		error = -EINVAL;
  		goto out;
  	}
  
  	switch (sock->state) {
  	default:
  		error = -EINVAL;
  		goto out;
  	case SS_CONNECTED:
  		error = -EISCONN;
  		goto out;
  	case SS_CONNECTING:
  		if (test_bit(ATM_VF_WAITING, &vcc->flags)) {
  			error = -EALREADY;
  			goto out;
  		}
  		sock->state = SS_UNCONNECTED;
  		if (sk->sk_err) {
  			error = -sk->sk_err;
  			goto out;
  		}
  		break;
  	case SS_UNCONNECTED:
  		addr = (struct sockaddr_atmsvc *) sockaddr;
  		if (addr->sas_family != AF_ATMSVC) {
  			error = -EAFNOSUPPORT;
  			goto out;
  		}
  		if (!test_bit(ATM_VF_HASQOS, &vcc->flags)) {
  			error = -EBADFD;
  			goto out;
  		}
  		if (vcc->qos.txtp.traffic_class == ATM_ANYCLASS ||
  		    vcc->qos.rxtp.traffic_class == ATM_ANYCLASS) {
  			error = -EINVAL;
  			goto out;
  		}
  		if (!vcc->qos.txtp.traffic_class &&
  		    !vcc->qos.rxtp.traffic_class) {
  			error = -EINVAL;
  			goto out;
  		}
  		vcc->remote = *addr;
  		set_bit(ATM_VF_WAITING, &vcc->flags);

  		sigd_enq(vcc, as_connect, NULL, NULL, &vcc->remote);

  		if (flags & O_NONBLOCK) {

  			sock->state = SS_CONNECTING;
  			error = -EINPROGRESS;
  			goto out;
  		}
  		error = 0;

  		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);

  		while (test_bit(ATM_VF_WAITING, &vcc->flags) && sigd) {
  			schedule();
  			if (!signal_pending(current)) {

  				prepare_to_wait(sk_sleep(sk), &wait,

  						TASK_INTERRUPTIBLE);

  				continue;
  			}

  			pr_debug("*ABORT*
  ");

  			/*
  			 * This is tricky:
  			 *   Kernel ---close--> Demon
  			 *   Kernel <--close--- Demon

  			 * or

  			 *   Kernel ---close--> Demon
  			 *   Kernel <--error--- Demon
  			 * or
  			 *   Kernel ---close--> Demon
  			 *   Kernel <--okay---- Demon
  			 *   Kernel <--close--- Demon
  			 */

  			sigd_enq(vcc, as_close, NULL, NULL, NULL);

  			while (test_bit(ATM_VF_WAITING, &vcc->flags) && sigd) {

  				prepare_to_wait(sk_sleep(sk), &wait,

  						TASK_INTERRUPTIBLE);

  				schedule();
  			}
  			if (!sk->sk_err)

  				while (!test_bit(ATM_VF_RELEASED, &vcc->flags) &&
  				       sigd) {

  					prepare_to_wait(sk_sleep(sk), &wait,

  							TASK_INTERRUPTIBLE);

  					schedule();
  				}

  			clear_bit(ATM_VF_REGIS, &vcc->flags);
  			clear_bit(ATM_VF_RELEASED, &vcc->flags);
  			clear_bit(ATM_VF_CLOSE, &vcc->flags);

  			    /* we're gone now but may connect later */
  			error = -EINTR;
  			break;
  		}

  		finish_wait(sk_sleep(sk), &wait);

  		if (error)
  			goto out;
  		if (!sigd) {
  			error = -EUNATCH;
  			goto out;
  		}
  		if (sk->sk_err) {
  			error = -sk->sk_err;
  			goto out;
  		}
  	}

  	vcc->qos.txtp.max_pcr = SELECT_TOP_PCR(vcc->qos.txtp);
  	vcc->qos.txtp.pcr = 0;
  	vcc->qos.txtp.min_pcr = 0;

  	error = vcc_connect(sock, vcc->itf, vcc->vpi, vcc->vci);
  	if (!error)

  		sock->state = SS_CONNECTED;
  	else

  		(void)svc_disconnect(vcc);

  out:
  	release_sock(sk);
  	return error;
  }

  static int svc_listen(struct socket *sock, int backlog)

  {
  	DEFINE_WAIT(wait);
  	struct sock *sk = sock->sk;
  	struct atm_vcc *vcc = ATM_SD(sock);
  	int error;

  	pr_debug("%p
  ", vcc);

  	lock_sock(sk);
  	/* let server handle listen on unbound sockets */

  	if (test_bit(ATM_VF_SESSION, &vcc->flags)) {

  		error = -EINVAL;
  		goto out;
  	}

  	if (test_bit(ATM_VF_LISTEN, &vcc->flags)) {
  		error = -EADDRINUSE;
  		goto out;

  	}

  	set_bit(ATM_VF_WAITING, &vcc->flags);

  	sigd_enq(vcc, as_listen, NULL, NULL, &vcc->local);

  	for (;;) {

  		prepare_to_wait(sk_sleep(sk), &wait, TASK_UNINTERRUPTIBLE);

  		if (!test_bit(ATM_VF_WAITING, &vcc->flags) || !sigd)
  			break;
  		schedule();

  	}

  	finish_wait(sk_sleep(sk), &wait);

  	if (!sigd) {
  		error = -EUNATCH;
  		goto out;
  	}

  	set_bit(ATM_VF_LISTEN, &vcc->flags);

  	vcc_insert_socket(sk);

  	sk->sk_max_ack_backlog = backlog > 0 ? backlog : ATM_BACKLOG_DEFAULT;
  	error = -sk->sk_err;
  out:
  	release_sock(sk);
  	return error;
  }

  static int svc_accept(struct socket *sock, struct socket *newsock, int flags,
  		      bool kern)

  {
  	struct sock *sk = sock->sk;
  	struct sk_buff *skb;
  	struct atmsvc_msg *msg;
  	struct atm_vcc *old_vcc = ATM_SD(sock);
  	struct atm_vcc *new_vcc;
  	int error;
  
  	lock_sock(sk);

  	error = svc_create(sock_net(sk), newsock, 0, kern);

  	if (error)
  		goto out;
  
  	new_vcc = ATM_SD(newsock);

  	pr_debug("%p -> %p
  ", old_vcc, new_vcc);

  	while (1) {
  		DEFINE_WAIT(wait);

  		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);

  		while (!(skb = skb_dequeue(&sk->sk_receive_queue)) &&
  		       sigd) {

  			if (test_bit(ATM_VF_RELEASED, &old_vcc->flags))
  				break;
  			if (test_bit(ATM_VF_CLOSE, &old_vcc->flags)) {

  				error = -sk->sk_err;
  				break;
  			}
  			if (flags & O_NONBLOCK) {
  				error = -EAGAIN;
  				break;
  			}
  			release_sock(sk);
  			schedule();
  			lock_sock(sk);
  			if (signal_pending(current)) {
  				error = -ERESTARTSYS;
  				break;
  			}

  			prepare_to_wait(sk_sleep(sk), &wait,

  					TASK_INTERRUPTIBLE);

  		}

  		finish_wait(sk_sleep(sk), &wait);

  		if (error)
  			goto out;
  		if (!skb) {
  			error = -EUNATCH;
  			goto out;
  		}

  		msg = (struct atmsvc_msg *)skb->data;

  		new_vcc->qos = msg->qos;

  		set_bit(ATM_VF_HASQOS, &new_vcc->flags);

  		new_vcc->remote = msg->svc;
  		new_vcc->local = msg->local;
  		new_vcc->sap = msg->sap;
  		error = vcc_connect(newsock, msg->pvc.sap_addr.itf,

  				    msg->pvc.sap_addr.vpi,
  				    msg->pvc.sap_addr.vci);

  		dev_kfree_skb(skb);
  		sk->sk_ack_backlog--;
  		if (error) {

  			sigd_enq2(NULL, as_reject, old_vcc, NULL, NULL,
  				  &old_vcc->qos, error);

  			error = error == -EAGAIN ? -EBUSY : error;
  			goto out;
  		}
  		/* wait should be short, so we ignore the non-blocking flag */
  		set_bit(ATM_VF_WAITING, &new_vcc->flags);

  		sigd_enq(new_vcc, as_accept, old_vcc, NULL, NULL);

  		for (;;) {
  			prepare_to_wait(sk_sleep(sk_atm(new_vcc)), &wait,
  					TASK_UNINTERRUPTIBLE);
  			if (!test_bit(ATM_VF_WAITING, &new_vcc->flags) || !sigd)
  				break;

  			release_sock(sk);
  			schedule();
  			lock_sock(sk);

  		}

  		finish_wait(sk_sleep(sk_atm(new_vcc)), &wait);

  		if (!sigd) {
  			error = -EUNATCH;
  			goto out;
  		}
  		if (!sk_atm(new_vcc)->sk_err)
  			break;
  		if (sk_atm(new_vcc)->sk_err != ERESTARTSYS) {
  			error = -sk_atm(new_vcc)->sk_err;
  			goto out;
  		}
  	}
  	newsock->state = SS_CONNECTED;
  out:
  	release_sock(sk);
  	return error;
  }

  static int svc_getname(struct socket *sock, struct sockaddr *sockaddr,
  		       int *sockaddr_len, int peer)

  {
  	struct sockaddr_atmsvc *addr;
  
  	*sockaddr_len = sizeof(struct sockaddr_atmsvc);
  	addr = (struct sockaddr_atmsvc *) sockaddr;

  	memcpy(addr, peer ? &ATM_SD(sock)->remote : &ATM_SD(sock)->local,
  	       sizeof(struct sockaddr_atmsvc));

  	return 0;
  }

  int svc_change_qos(struct atm_vcc *vcc, struct atm_qos *qos)

  {
  	struct sock *sk = sk_atm(vcc);
  	DEFINE_WAIT(wait);
  
  	set_bit(ATM_VF_WAITING, &vcc->flags);

  	sigd_enq2(vcc, as_modify, NULL, NULL, &vcc->local, qos, 0);

  	for (;;) {

  		prepare_to_wait(sk_sleep(sk), &wait, TASK_UNINTERRUPTIBLE);

  		if (!test_bit(ATM_VF_WAITING, &vcc->flags) ||
  		    test_bit(ATM_VF_RELEASED, &vcc->flags) || !sigd) {
  			break;
  		}
  		schedule();

  	}

  	finish_wait(sk_sleep(sk), &wait);

  	if (!sigd)
  		return -EUNATCH;

  	return -sk->sk_err;
  }

  static int svc_setsockopt(struct socket *sock, int level, int optname,

  			  char __user *optval, unsigned int optlen)

  {
  	struct sock *sk = sock->sk;
  	struct atm_vcc *vcc = ATM_SD(sock);
  	int value, error = 0;
  
  	lock_sock(sk);
  	switch (optname) {

  	case SO_ATMSAP:
  		if (level != SOL_ATM || optlen != sizeof(struct atm_sap)) {
  			error = -EINVAL;
  			goto out;
  		}
  		if (copy_from_user(&vcc->sap, optval, optlen)) {
  			error = -EFAULT;
  			goto out;
  		}
  		set_bit(ATM_VF_HASSAP, &vcc->flags);
  		break;
  	case SO_MULTIPOINT:
  		if (level != SOL_ATM || optlen != sizeof(int)) {
  			error = -EINVAL;
  			goto out;
  		}
  		if (get_user(value, (int __user *)optval)) {
  			error = -EFAULT;
  			goto out;
  		}
  		if (value == 1)
  			set_bit(ATM_VF_SESSION, &vcc->flags);
  		else if (value == 0)
  			clear_bit(ATM_VF_SESSION, &vcc->flags);
  		else
  			error = -EINVAL;
  		break;
  	default:
  		error = vcc_setsockopt(sock, level, optname, optval, optlen);

  	}
  
  out:
  	release_sock(sk);
  	return error;
  }

  static int svc_getsockopt(struct socket *sock, int level, int optname,
  			  char __user *optval, int __user *optlen)

  {
  	struct sock *sk = sock->sk;
  	int error = 0, len;
  
  	lock_sock(sk);
  	if (!__SO_LEVEL_MATCH(optname, level) || optname != SO_ATMSAP) {
  		error = vcc_getsockopt(sock, level, optname, optval, optlen);
  		goto out;
  	}
  	if (get_user(len, optlen)) {
  		error = -EFAULT;
  		goto out;
  	}
  	if (len != sizeof(struct atm_sap)) {
  		error = -EINVAL;
  		goto out;
  	}
  	if (copy_to_user(optval, &ATM_SD(sock)->sap, sizeof(struct atm_sap))) {
  		error = -EFAULT;
  		goto out;
  	}
  out:
  	release_sock(sk);
  	return error;
  }

  static int svc_addparty(struct socket *sock, struct sockaddr *sockaddr,
  			int sockaddr_len, int flags)
  {
  	DEFINE_WAIT(wait);
  	struct sock *sk = sock->sk;
  	struct atm_vcc *vcc = ATM_SD(sock);
  	int error;
  
  	lock_sock(sk);
  	set_bit(ATM_VF_WAITING, &vcc->flags);

  	sigd_enq(vcc, as_addparty, NULL, NULL,

  		 (struct sockaddr_atmsvc *) sockaddr);

  	if (flags & O_NONBLOCK) {

  		error = -EINPROGRESS;
  		goto out;
  	}

  	pr_debug("added wait queue
  ");

  	for (;;) {

  		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);

  		if (!test_bit(ATM_VF_WAITING, &vcc->flags) || !sigd)
  			break;
  		schedule();

  	}

  	finish_wait(sk_sleep(sk), &wait);

  	error = -xchg(&sk->sk_err_soft, 0);

  out:
  	release_sock(sk);
  	return error;
  }

  static int svc_dropparty(struct socket *sock, int ep_ref)
  {
  	DEFINE_WAIT(wait);
  	struct sock *sk = sock->sk;
  	struct atm_vcc *vcc = ATM_SD(sock);
  	int error;
  
  	lock_sock(sk);
  	set_bit(ATM_VF_WAITING, &vcc->flags);

  	sigd_enq2(vcc, as_dropparty, NULL, NULL, NULL, NULL, ep_ref);

  	for (;;) {

  		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);

  		if (!test_bit(ATM_VF_WAITING, &vcc->flags) || !sigd)
  			break;
  		schedule();

  	}

  	finish_wait(sk_sleep(sk), &wait);

  	if (!sigd) {
  		error = -EUNATCH;
  		goto out;
  	}

  	error = -xchg(&sk->sk_err_soft, 0);

  out:
  	release_sock(sk);
  	return error;
  }

  static int svc_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
  {

  	int error, ep_ref;
  	struct sockaddr_atmsvc sa;

  	struct atm_vcc *vcc = ATM_SD(sock);

  	switch (cmd) {

  	case ATM_ADDPARTY:
  		if (!test_bit(ATM_VF_SESSION, &vcc->flags))
  			return -EINVAL;
  		if (copy_from_user(&sa, (void __user *) arg, sizeof(sa)))
  			return -EFAULT;
  		error = svc_addparty(sock, (struct sockaddr *)&sa, sizeof(sa),
  				     0);
  		break;
  	case ATM_DROPPARTY:
  		if (!test_bit(ATM_VF_SESSION, &vcc->flags))
  			return -EINVAL;
  		if (copy_from_user(&ep_ref, (void __user *) arg, sizeof(int)))
  			return -EFAULT;
  		error = svc_dropparty(sock, ep_ref);
  		break;
  	default:
  		error = vcc_ioctl(sock, cmd, arg);

  	}
  
  	return error;
  }

  #ifdef CONFIG_COMPAT

  static int svc_compat_ioctl(struct socket *sock, unsigned int cmd,
  			    unsigned long arg)

  {
  	/* The definition of ATM_ADDPARTY uses the size of struct atm_iobuf.
  	   But actually it takes a struct sockaddr_atmsvc, which doesn't need
  	   compat handling. So all we have to do is fix up cmd... */
  	if (cmd == COMPAT_ATM_ADDPARTY)
  		cmd = ATM_ADDPARTY;
  
  	if (cmd == ATM_ADDPARTY || cmd == ATM_DROPPARTY)
  		return svc_ioctl(sock, cmd, arg);
  	else
  		return vcc_compat_ioctl(sock, cmd, arg);
  }
  #endif /* CONFIG_COMPAT */

  static const struct proto_ops svc_proto_ops = {

  	.family =	PF_ATMSVC,
  	.owner =	THIS_MODULE,
  
  	.release =	svc_release,
  	.bind =		svc_bind,
  	.connect =	svc_connect,
  	.socketpair =	sock_no_socketpair,
  	.accept =	svc_accept,
  	.getname =	svc_getname,
  	.poll =		vcc_poll,
  	.ioctl =	svc_ioctl,

  #ifdef CONFIG_COMPAT
  	.compat_ioctl =	svc_compat_ioctl,
  #endif

  	.listen =	svc_listen,
  	.shutdown =	svc_shutdown,
  	.setsockopt =	svc_setsockopt,
  	.getsockopt =	svc_getsockopt,
  	.sendmsg =	vcc_sendmsg,
  	.recvmsg =	vcc_recvmsg,
  	.mmap =		sock_no_mmap,
  	.sendpage =	sock_no_sendpage,
  };

  static int svc_create(struct net *net, struct socket *sock, int protocol,
  		      int kern)

  {
  	int error;

  	if (!net_eq(net, &init_net))

  		return -EAFNOSUPPORT;

  	sock->ops = &svc_proto_ops;

  	error = vcc_create(net, sock, protocol, AF_ATMSVC, kern);

  	if (error)
  		return error;

  	ATM_SD(sock)->local.sas_family = AF_ATMSVC;
  	ATM_SD(sock)->remote.sas_family = AF_ATMSVC;
  	return 0;
  }

  static const struct net_proto_family svc_family_ops = {

  	.family = PF_ATMSVC,
  	.create = svc_create,
  	.owner = THIS_MODULE,
  };
  
  
  /*
   *	Initialize the ATM SVC protocol family
   */
  
  int __init atmsvc_init(void)
  {
  	return sock_register(&svc_family_ops);
  }
  
  void atmsvc_exit(void)
  {
  	sock_unregister(PF_ATMSVC);
  }