net/atm/signaling.c

/* net/atm/signaling.c - ATM signaling */

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

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

#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/atm.h>		/* ATM stuff */
#include <linux/atmsap.h>
#include <linux/atmsvc.h>
#include <linux/atmdev.h>
#include <linux/bitops.h>

#include "resources.h"
#include "signaling.h"


#undef WAIT_FOR_DEMON		/* #define this if system calls on SVC sockets
				   should block until the demon runs.
				   Danger: may cause nasty hangs if the demon
				   crashes. */

struct atm_vcc *sigd = NULL;
#ifdef WAIT_FOR_DEMON
static DECLARE_WAIT_QUEUE_HEAD(sigd_sleep);
#endif


static void sigd_put_skb(struct sk_buff *skb)
{
#ifdef WAIT_FOR_DEMON
	DECLARE_WAITQUEUE(wait,current);

	add_wait_queue(&sigd_sleep,&wait);
	while (!sigd) {
		set_current_state(TASK_UNINTERRUPTIBLE);
		pr_debug("atmsvc: waiting for signaling daemon...\n");
		schedule();
	}
	current->state = TASK_RUNNING;
	remove_wait_queue(&sigd_sleep,&wait);
#else
	if (!sigd) {
		pr_debug("atmsvc: no signaling daemon\n");
		kfree_skb(skb);
		return;
	}
#endif
	atm_force_charge(sigd,skb->truesize);
	skb_queue_tail(&sk_atm(sigd)->sk_receive_queue,skb);
	sk_atm(sigd)->sk_data_ready(sk_atm(sigd), skb->len);
}


static void modify_qos(struct atm_vcc *vcc,struct atmsvc_msg *msg)
{
	struct sk_buff *skb;

	if (test_bit(ATM_VF_RELEASED,&vcc->flags) ||
	    !test_bit(ATM_VF_READY,&vcc->flags))
		return;
	msg->type = as_error;
	if (!vcc->dev->ops->change_qos) msg->reply = -EOPNOTSUPP;
	else {
		/* should lock VCC */
		msg->reply = vcc->dev->ops->change_qos(vcc,&msg->qos,
		    msg->reply);
		if (!msg->reply) msg->type = as_okay;
	}
	/*
	 * Should probably just turn around the old skb. But the, the buffer
	 * space accounting needs to follow the change too. Maybe later.
	 */
	while (!(skb = alloc_skb(sizeof(struct atmsvc_msg),GFP_KERNEL)))
		schedule();
	*(struct atmsvc_msg *) skb_put(skb,sizeof(struct atmsvc_msg)) = *msg;
	sigd_put_skb(skb);
}


static int sigd_send(struct atm_vcc *vcc,struct sk_buff *skb)
{
	struct atmsvc_msg *msg;
	struct atm_vcc *session_vcc;
	struct sock *sk;

	msg = (struct atmsvc_msg *) skb->data;
	atomic_sub(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
	vcc = *(struct atm_vcc **) &msg->vcc;
	pr_debug("%d (0x%lx)\n", (int)msg->type, (unsigned long)vcc);
	sk = sk_atm(vcc);

	switch (msg->type) {
		case as_okay:
			sk->sk_err = -msg->reply;
			clear_bit(ATM_VF_WAITING, &vcc->flags);
			if (!*vcc->local.sas_addr.prv &&
			    !*vcc->local.sas_addr.pub) {
				vcc->local.sas_family = AF_ATMSVC;
				memcpy(vcc->local.sas_addr.prv,
				    msg->local.sas_addr.prv,ATM_ESA_LEN);
				memcpy(vcc->local.sas_addr.pub,
				    msg->local.sas_addr.pub,ATM_E164_LEN+1);
			}
			session_vcc = vcc->session ? vcc->session : vcc;
			if (session_vcc->vpi || session_vcc->vci) break;
			session_vcc->itf = msg->pvc.sap_addr.itf;
			session_vcc->vpi = msg->pvc.sap_addr.vpi;
			session_vcc->vci = msg->pvc.sap_addr.vci;
			if (session_vcc->vpi || session_vcc->vci)
				session_vcc->qos = msg->qos;
			break;
		case as_error:
			clear_bit(ATM_VF_REGIS,&vcc->flags);
			clear_bit(ATM_VF_READY,&vcc->flags);
			sk->sk_err = -msg->reply;
			clear_bit(ATM_VF_WAITING, &vcc->flags);
			break;
		case as_indicate:
			vcc = *(struct atm_vcc **) &msg->listen_vcc;
			sk = sk_atm(vcc);
			pr_debug("as_indicate!!!\n");
			lock_sock(sk);
			if (sk_acceptq_is_full(sk)) {
				sigd_enq(NULL,as_reject,vcc,NULL,NULL);
				dev_kfree_skb(skb);
				goto as_indicate_complete;
			}
			sk->sk_ack_backlog++;
			skb_queue_tail(&sk->sk_receive_queue, skb);
			pr_debug("waking sk->sk_sleep 0x%p\n", sk->sk_sleep);
			sk->sk_state_change(sk);
as_indicate_complete:
			release_sock(sk);
			return 0;
		case as_close:
			set_bit(ATM_VF_RELEASED,&vcc->flags);
			vcc_release_async(vcc, msg->reply);
			goto out;
		case as_modify:
			modify_qos(vcc,msg);
			break;
		case as_addparty:
		case as_dropparty:
			sk->sk_err_soft = msg->reply;	/* < 0 failure, otherwise ep_ref */
			clear_bit(ATM_VF_WAITING, &vcc->flags);
			break;
		default:
			pr_alert("bad message type %d\n", (int)msg->type);
			return -EINVAL;
	}
	sk->sk_state_change(sk);
out:
	dev_kfree_skb(skb);
	return 0;
}


void sigd_enq2(struct atm_vcc *vcc,enum atmsvc_msg_type type,
    struct atm_vcc *listen_vcc,const struct sockaddr_atmpvc *pvc,
    const struct sockaddr_atmsvc *svc,const struct atm_qos *qos,int reply)
{
	struct sk_buff *skb;
	struct atmsvc_msg *msg;
	static unsigned session = 0;

	pr_debug("%d (0x%p)\n", (int)type, vcc);
	while (!(skb = alloc_skb(sizeof(struct atmsvc_msg),GFP_KERNEL)))
		schedule();
	msg = (struct atmsvc_msg *) skb_put(skb,sizeof(struct atmsvc_msg));
	memset(msg,0,sizeof(*msg));
	msg->type = type;
	*(struct atm_vcc **) &msg->vcc = vcc;
	*(struct atm_vcc **) &msg->listen_vcc = listen_vcc;
	msg->reply = reply;
	if (qos) msg->qos = *qos;
	if (vcc) msg->sap = vcc->sap;
	if (svc) msg->svc = *svc;
	if (vcc) msg->local = vcc->local;
	if (pvc) msg->pvc = *pvc;
	if (vcc) {
		if (type == as_connect && test_bit(ATM_VF_SESSION, &vcc->flags))
			msg->session = ++session;
			/* every new pmp connect gets the next session number */
	}
	sigd_put_skb(skb);
	if (vcc) set_bit(ATM_VF_REGIS,&vcc->flags);
}


void sigd_enq(struct atm_vcc *vcc,enum atmsvc_msg_type type,
    struct atm_vcc *listen_vcc,const struct sockaddr_atmpvc *pvc,
    const struct sockaddr_atmsvc *svc)
{
	sigd_enq2(vcc,type,listen_vcc,pvc,svc,vcc ? &vcc->qos : NULL,0);
	/* other ISP applications may use "reply" */
}


static void purge_vcc(struct atm_vcc *vcc)
{
	if (sk_atm(vcc)->sk_family == PF_ATMSVC &&
	    !test_bit(ATM_VF_META, &vcc->flags)) {
		set_bit(ATM_VF_RELEASED, &vcc->flags);
		clear_bit(ATM_VF_REGIS, &vcc->flags);
		vcc_release_async(vcc, -EUNATCH);
	}
}


static void sigd_close(struct atm_vcc *vcc)
{
	struct hlist_node *node;
	struct sock *s;
	int i;

	pr_debug("\n");
	sigd = NULL;
	if (skb_peek(&sk_atm(vcc)->sk_receive_queue))
		pr_err("closing with requests pending\n");
	skb_queue_purge(&sk_atm(vcc)->sk_receive_queue);

	read_lock(&vcc_sklist_lock);
	for(i = 0; i < VCC_HTABLE_SIZE; ++i) {
		struct hlist_head *head = &vcc_hash[i];

		sk_for_each(s, node, head) {
			vcc = atm_sk(s);

			purge_vcc(vcc);
		}
	}
	read_unlock(&vcc_sklist_lock);
}


static struct atmdev_ops sigd_dev_ops = {
	.close = sigd_close,
	.send =	sigd_send
};


static struct atm_dev sigd_dev = {
	.ops =		&sigd_dev_ops,
	.type =		"sig",
	.number =	999,
	.lock =		__SPIN_LOCK_UNLOCKED(sigd_dev.lock)
};


int sigd_attach(struct atm_vcc *vcc)
{
	if (sigd) return -EADDRINUSE;
	pr_debug("\n");
	sigd = vcc;
	vcc->dev = &sigd_dev;
	vcc_insert_socket(sk_atm(vcc));
	set_bit(ATM_VF_META,&vcc->flags);
	set_bit(ATM_VF_READY,&vcc->flags);
#ifdef WAIT_FOR_DEMON
	wake_up(&sigd_sleep);
#endif
	return 0;
}