path: root/net/atm/common.c

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

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

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

#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 <linux/slab.h>
#include <net/sock.h>		/* struct sock */
#include <linux/uaccess.h>
#include <linux/poll.h>

#include <asm/atomic.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];
EXPORT_SYMBOL(vcc_hash);

DEFINE_RWLOCK(vcc_sklist_lock);
EXPORT_SYMBOL(vcc_sklist_lock);

static ATOMIC_NOTIFIER_HEAD(atm_dev_notify_chain);

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);
}
EXPORT_SYMBOL(vcc_insert_socket);

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

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

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

static void vcc_def_wakeup(struct sock *sk)
{
	struct socket_wq *wq;

	rcu_read_lock();
	wq = rcu_dereference(sk->sk_wq);
	if (wq_has_sleeper(wq))
		wake_up(&wq->wait);
	rcu_read_unlock();
}

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)
{
	struct socket_wq *wq;

	rcu_read_lock();

	if (vcc_writable(sk)) {
		wq = rcu_dereference(sk->sk_wq);
		if (wq_has_sleeper(wq))
			wake_up_interruptible(&wq->wait);

		sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
	}

	rcu_read_unlock();
}

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, 1);
	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