common.c

linux 内核源代码

/* net/atm/common.c - ATM sockets (common part for PVC and SVC) */

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


#include <linux/module.h>
#include <linux/kmod.h>
#include <linux/net.h>		/* struct socket, struct proto_ops */
#include <linux/atm.h>		/* ATM stuff */
#include <linux/atmdev.h>
#include <linux/socket.h>	/* SOL_SOCKET */
#include <linux/errno.h>	/* error codes */
#include <linux/capability.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/time.h>		/* struct timeval */
#include <linux/skbuff.h>
#include <linux/bitops.h>
#include <linux/init.h>
#include <net/sock.h>		/* struct sock */

#include <asm/uaccess.h>
#include <asm/atomic.h>
#include <asm/poll.h>


#include "resources.h"		/* atm_find_dev */
#include "common.h"		/* prototypes */
#include "protocols.h"		/* atm_init_<transport> */
#include "addr.h"		/* address registry */
#include "signaling.h"		/* for WAITING and sigd_attach */

struct hlist_head vcc_hash[VCC_HTABLE_SIZE];
DEFINE_RWLOCK(vcc_sklist_lock);

static void __vcc_insert_socket(struct sock *sk)
{
	struct atm_vcc *vcc = atm_sk(sk);
	struct hlist_head *head = &vcc_hash[vcc->vci &
					(VCC_HTABLE_SIZE - 1)];
	sk->sk_hash = vcc->vci & (VCC_HTABLE_SIZE - 1);
	sk_add_node(sk, head);
}

void vcc_insert_socket(struct sock *sk)
{
	write_lock_irq(&vcc_sklist_lock);
	__vcc_insert_socket(sk);
	write_unlock_irq(&vcc_sklist_lock);
}

static void vcc_remove_socket(struct sock *sk)
{
	write_lock_irq(&vcc_sklist_lock);
	sk_del_node_init(sk);
	write_unlock_irq(&vcc_sklist_lock);
}


static struct sk_buff *alloc_tx(struct atm_vcc *vcc,unsigned int size)
{
	struct sk_buff *skb;
	struct sock *sk = sk_atm(vcc);

	if (atomic_read(&sk->sk_wmem_alloc) && !atm_may_send(vcc, size)) {
		pr_debug("Sorry: wmem_alloc = %d, size = %d, sndbuf = %d\n",
			atomic_read(&sk->sk_wmem_alloc), size,
			sk->sk_sndbuf);
		return NULL;
	}
	while (!(skb = alloc_skb(size,GFP_KERNEL))) schedule();
	pr_debug("AlTx %d += %d\n", atomic_read(&sk->sk_wmem_alloc),
		skb->truesize);
	atomic_add(skb->truesize, &sk->sk_wmem_alloc);
	return skb;
}


EXPORT_SYMBOL(vcc_hash);
EXPORT_SYMBOL(vcc_sklist_lock);
EXPORT_SYMBOL(vcc_insert_socket);

static void vcc_sock_destruct(struct sock *sk)
{
	if (atomic_read(&sk->sk_rmem_alloc))
		printk(KERN_DEBUG "vcc_sock_destruct: rmem leakage (%d bytes) detected.\n", atomic_read(&sk->sk_rmem_alloc));

	if (atomic_read(&sk->sk_wmem_alloc))
		printk(KERN_DEBUG "vcc_sock_destruct: wmem leakage (%d bytes) detected.\n", atomic_read(&sk->sk_wmem_alloc));
}

static void vcc_def_wakeup(struct sock *sk)
{
	read_lock(&sk->sk_callback_lock);
	if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
		wake_up(sk->sk_sleep);
	read_unlock(&sk->sk_callback_lock);
}

static inline int vcc_writable(struct sock *sk)
{
	struct atm_vcc *vcc = atm_sk(sk);

	return (vcc->qos.txtp.max_sdu +
		atomic_read(&sk->sk_wmem_alloc)) <= sk->sk_sndbuf;
}

static void vcc_write_space(struct sock *sk)
{
	read_lock(&sk->sk_callback_lock);

	if (vcc_writable(sk)) {
		if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
			wake_up_interruptible(sk->sk_sleep);

		sk_wake_async(sk, 2, POLL_OUT);
	}

	read_unlock(&sk->sk_callback_lock);
}

static struct proto vcc_proto = {
	.name	  = "VCC",
	.owner	  = THIS_MODULE,
	.obj_size = sizeof(struct atm_vcc),
};

int vcc_create(struct net *net, struct socket *sock, int protocol, int family)
{
	struct sock *sk;
	struct atm_vcc *vcc;

	sock->sk = NULL;
	if (sock->type == SOCK_STREAM)
		return -EINVAL;
	sk = sk_alloc(net, family, GFP_KERNEL, &vcc_proto);
	if (!sk)
		return -ENOMEM;
	sock_init_data(sock, sk);
	sk->sk_state_change = vcc_def_wakeup;
	sk->sk_write_space = vcc_write_space;

	vcc = atm_sk(sk);
	vcc->dev = NULL;
	memset(&vcc->local,0,sizeof(struct sockaddr_atmsvc));
	memset(&vcc->remote,0,sizeof(struct sockaddr_atmsvc));
	vcc->qos.txtp.max_sdu = 1 << 16; /* for meta VCs */
	atomic_set(&sk->sk_wmem_alloc, 0);
	atomic_set(&sk->sk_rmem_alloc, 0);
	vcc->push = NULL;
	vcc->pop = NULL;
	vcc->push_oam = NULL;
	vcc->vpi = vcc->vci = 0; /* no VCI/VPI yet */
	vcc->atm_options = vcc->aal_options = 0;
	sk->sk_destruct = vcc_sock_destruct;
	return 0;
}


static void vcc_destroy_socket(struct sock *sk)
{
	struct atm_vcc *vcc = atm_sk(sk);
	struct sk_buff *skb;

	set_bit(ATM_VF_CLOSE, &vcc->flags);
	clear_bit(ATM_VF_READY, &vcc->flags);
	if (vcc->dev) {
		if (vcc->dev->ops->close)
			vcc->dev->ops->close(vcc);
		if (vcc->push)
			vcc->push(vcc, NULL); /* atmarpd has no push */

		while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
			atm_return(vcc,skb->truesize);
			kfree_skb(skb);
		}

		module_put(vcc->dev->ops->owner);
		atm_dev_put(vcc->dev);
	}

	vcc_remove_socket(sk);
}


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

	if (sk) {
		lock_sock(sk);
		vcc_destroy_socket(sock->sk);
		release_sock(sk);
		sock_put(sk);
	}

	return 0;
}


void vcc_release_async(struct atm_vcc *vcc, int reply)
{
	struct sock *sk = sk_atm(vcc);

	set_bit(ATM_VF_CLOSE, &vcc->flags);
	sk->sk_shutdown |= RCV_SHUTDOWN;
	sk->sk_err = -reply;
	clear_bit(ATM_VF_WAITING, &vcc->flags);
	sk->sk_state_change(sk);
}


EXPORT_SYMBOL(vcc_release_async);


void atm_dev_release_vccs(struct atm_dev *dev)
{
	int i;

	write_lock_irq(&vcc_sklist_lock);
	for (i = 0; i < VCC_HTABLE_SIZE; i++) {
		struct hlist_head *head = &vcc_hash[i];
		struct hlist_node *node, *tmp;
		struct sock *s;
		struct atm_vcc *vcc;

		sk_for_each_safe(s, node, tmp, head) {
			vcc = atm_sk(s);
			if (vcc->dev == dev) {
				vcc_release_async(vcc, -EPIPE);
				sk_del_node_init(s);
			}
		}
	}
	write_unlock_irq(&vcc_sklist_lock);
}


static int adjust_tp(struct atm_trafprm *tp,unsigned char aal)
{
	int max_sdu;

	if (!tp->traffic_class) return 0;
	switch (aal) {
		case ATM_AAL0:
			max_sdu = ATM_CELL_SIZE-1;
			break;
		case ATM_AAL34:
			max_sdu = ATM_MAX_AAL34_PDU;
			break;
		default:
			printk(KERN_WARNING "ATM: AAL problems ... "
			    "(%d)\n",aal);
			/* fall through */
		case ATM_AAL5:
			max_sdu = ATM_MAX_AAL5_PDU;
	}
	if (!tp->max_sdu) tp->max_sdu = max_sdu;
	else if (tp->max_sdu > max_sdu) return -EINVAL;
	if (!tp->max_cdv) tp->max_cdv = ATM_MAX_CDV;
	return 0;
}


static int check_ci(struct atm_vcc *vcc, short vpi, int vci)
{
	struct hlist_head *head = &vcc_hash[vci &
					(VCC_HTABLE_SIZE - 1)];
	struct hlist_node *node;
	struct sock *s;
	struct atm_vcc *walk;

	sk_for_each(s, node, head) {
		walk = atm_sk(s);
		if (walk->dev != vcc->dev)
			continue;
		if (test_bit(ATM_VF_ADDR, &walk->flags) && walk->vpi == vpi &&
		    walk->vci == vci && ((walk->qos.txtp.traffic_class !=
		    ATM_NONE && vcc->qos.txtp.traffic_class != ATM_NONE) ||
		    (walk->qos.rxtp.traffic_class != ATM_NONE &&
		    vcc->qos.rxtp.traffic_class != ATM_NONE)))
			return -EADDRINUSE;
	}

	/* allow VCCs with same VPI/VCI iff they don't collide on
	   TX/RX (but we may refuse such sharing for other reasons,
	   e.g. if protocol requires to have both channels) */

	return 0;
}


static int find_ci(struct atm_vcc *vcc, short *vpi, int *vci)
{
	static short p;        /* poor man's per-device cache */
	static int c;
	short old_p;
	int old_c;
	int err;

	if (*vpi != ATM_VPI_ANY && *vci != ATM_VCI_ANY) {
		err = check_ci(vcc, *vpi, *vci);
		return err;
	}
	/* last scan may have left values out of bounds for current device */
	if (*vpi != ATM_VPI_ANY)
		p = *vpi;
	else if (p >= 1 << vcc->dev->ci_range.vpi_bits)
		p = 0;
	if (*vci != ATM_VCI_ANY)
		c = *vci;
	else if (c < ATM_NOT_RSV_VCI || c >= 1 << vcc->dev->ci_range.vci_bits)
			c = ATM_NOT_RSV_VCI;
	old_p = p;
	old_c = c;
	do {
		if (!check_ci(vcc, p, c)) {
			*vpi = p;
			*vci = c;
			return 0;
		}
		if (*vci == ATM_VCI_ANY) {
			c++;
			if (c >= 1 << vcc->dev->ci_range.vci_bits)
				c = ATM_NOT_RSV_VCI;
		}
		if ((c == ATM_NOT_RSV_VCI || *vci != ATM_VCI_ANY) &&
		    *vpi == ATM_VPI_ANY) {
			p++;
			if (p >= 1 << vcc->dev->ci_range.vpi_bits) p = 0;
		}
	}
	while (old_p != p || old_c != c);
	return -EADDRINUSE;
}


static int __vcc_connect(struct atm_vcc *vcc, struct atm_dev *dev, short vpi,
			 int vci)
{
	struct sock *sk = sk_atm(vcc);
	int error;

	if ((vpi != ATM_VPI_UNSPEC && vpi != ATM_VPI_ANY &&
	    vpi >> dev->ci_range.vpi_bits) || (vci != ATM_VCI_UNSPEC &&
	    vci != ATM_VCI_ANY && vci >> dev->ci_range.vci_bits))
		return -EINVAL;
	if (vci > 0 && vci < ATM_NOT_RSV_VCI && !capable(CAP_NET_BIND_SERVICE))
		return -EPERM;
	error = -ENODEV;
	if (!try_module_get(dev->ops->owner))
		return error;
	vcc->dev = dev;
	write_lock_irq(&vcc_sklist_lock);
	if (test_bit(ATM_DF_REMOVED, &dev->flags) ||
	    (error = find_ci(vcc, &vpi, &vci))) {
		write_unlock_irq(&vcc_sklist_lock);
		goto fail_module_put;
	}
	vcc->vpi = vpi;
	vcc->vci = vci;
	__vcc_insert_socket(sk);
	write_unlock_irq(&vcc_sklist_lock);
	switch (vcc->qos.aal) {
		case ATM_AAL0:
			error = atm_init_aal0(vcc);
			vcc->stats = &dev->stats.aal0;
			break;
		case ATM_AAL34:
			error = atm_init_aal34(vcc);
			vcc->stats = &dev->stats.aal34;
			break;
		case ATM_NO_AAL:
			/* ATM_AAL5 is also used in the "0 for default" case */
			vcc->qos.aal = ATM_AAL5;
			/* fall through */
		case ATM_AAL5:
			error = atm_init_aal5(vcc);
			vcc->stats = &dev->stats.aal5;
			break;
		default:
			error = -EPROTOTYPE;
	}
	if (!error) error = adjust_tp(&vcc->qos.txtp,vcc->qos.aal);
	if (!error) error = adjust_tp(&vcc->qos.rxtp,vcc->qos.aal);
	if (error)
		goto fail;
	pr_debug("VCC %d.%d, AAL %d\n",vpi,vci,vcc->qos.aal);
	pr_debug("  TX: %d, PCR %d..%d, SDU %d\n",vcc->qos.txtp.traffic_class,
	    vcc->qos.txtp.min_pcr,vcc->qos.txtp.max_pcr,vcc->qos.txtp.max_sdu);
	pr_debug("  RX: %d, PCR %d..%d, SDU %d\n",vcc->qos.rxtp.traffic_class,
	    vcc->qos.rxtp.min_pcr,vcc->qos.rxtp.max_pcr,vcc->qos.rxtp.max_sdu);

	if (dev->ops->open) {
		if ((error = dev->ops->open(vcc)))
			goto fail;
	}
	return 0;

fail:
	vcc_remove_socket(sk);
fail_module_put:
	module_put(dev->ops->owner);
	/* ensure we get dev module ref count correct */
	vcc->dev = NULL;
	return error;
}


int vcc_connect(struct socket *sock, int itf, short vpi, int vci)