svc.c

linux 内核源代码

/* net/atm/svc.c - ATM SVC sockets */

/* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA */


#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.h>	/* jiffies and HZ */
#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 <asm/uaccess.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);

/*
 * 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("svc_disconnect %p\n",vcc);
	if (test_bit(ATM_VF_REGIS,&vcc->flags)) {
		prepare_to_wait(sk->sk_sleep, &wait, TASK_UNINTERRUPTIBLE);
		sigd_enq(vcc,as_close,NULL,NULL,NULL);
		while (!test_bit(ATM_VF_RELEASED,&vcc->flags) && sigd) {
			schedule();
			prepare_to_wait(sk->sk_sleep, &wait, TASK_UNINTERRUPTIBLE);
		}
		finish_wait(sk->sk_sleep, &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\n");
		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("svc_release %p\n", 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);
	prepare_to_wait(sk->sk_sleep, &wait, TASK_UNINTERRUPTIBLE);
	sigd_enq(vcc,as_bind,NULL,NULL,&vcc->local);
	while (test_bit(ATM_VF_WAITING, &vcc->flags) && sigd) {
		schedule();
		prepare_to_wait(sk->sk_sleep, &wait, TASK_UNINTERRUPTIBLE);
	}
	finish_wait(sk->sk_sleep, &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("svc_connect %p\n",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);
		prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
		sigd_enq(vcc,as_connect,NULL,NULL,&vcc->remote);
		if (flags & O_NONBLOCK) {
			finish_wait(sk->sk_sleep, &wait);
			sock->state = SS_CONNECTING;
			error = -EINPROGRESS;
			goto out;
		}
		error = 0;
		while (test_bit(ATM_VF_WAITING, &vcc->flags) && sigd) {
			schedule();
			if (!signal_pending(current)) {
				prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
				continue;
			}
			pr_debug("*ABORT*\n");
			/*
			 * 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->sk_sleep, &wait, TASK_INTERRUPTIBLE);
				schedule();
			}
			if (!sk->sk_err)
				while (!test_bit(ATM_VF_RELEASED,&vcc->flags)
				    && sigd) {
					prepare_to_wait(sk->sk_sleep, &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->sk_sleep, &wait);
		if (error)
			goto out;
		if (!sigd) {
			error = -EUNATCH;
			goto out;
		}
		if (sk->sk_err) {
			error = -sk->sk_err;
			goto out;
		}
	}
/*
 * Not supported yet
 *
 * #ifndef CONFIG_SINGLE_SIGITF
 */
	vcc->qos.txtp.max_pcr = SELECT_TOP_PCR(vcc->qos.txtp);
	vcc->qos.txtp.pcr = 0;
	vcc->qos.txtp.min_pcr = 0;
/*
 * #endif
 */
	if (!(error = vcc_connect(sock, vcc->itf, vcc->vpi, vcc->vci)))
		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("svc_listen %p\n",vcc);
	lock_sock(sk);
	/* let server handle listen on unbound sockets */
	if (test_bit(ATM_VF_SESSION,&vcc->flags)) {
		error = -EINVAL;
		goto out;
	}
	vcc_insert_socket(sk);
	set_bit(ATM_VF_WAITING, &vcc->flags);
	prepare_to_wait(sk->sk_sleep, &wait, TASK_UNINTERRUPTIBLE);
	sigd_enq(vcc,as_listen,NULL,NULL,&vcc->local);
	while (test_bit(ATM_VF_WAITING, &vcc->flags) && sigd) {
		schedule();
		prepare_to_wait(sk->sk_sleep, &wait, TASK_UNINTERRUPTIBLE);
	}
	finish_wait(sk->sk_sleep, &wait);
	if (!sigd) {
		error = -EUNATCH;
		goto out;
	}
	set_bit(ATM_VF_LISTEN,&vcc->flags);
	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)
{
	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(sk->sk_net, newsock,0);
	if (error)
		goto out;

	new_vcc = ATM_SD(newsock);