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root/net/x25/x25_link.c

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DEFINITIONS

This source file includes following definitions.
  1. x25_start_t20timer
  2. x25_t20timer_expiry
  3. x25_stop_t20timer
  4. x25_t20timer_pending
  5. x25_link_control
  6. x25_transmit_restart_request
  7. x25_transmit_restart_confirmation
  8. x25_transmit_clear_request
  9. x25_transmit_link
  10. x25_link_established
  11. x25_link_terminated
  12. x25_link_device_up
  13. __x25_remove_neigh
  14. x25_link_device_down
  15. x25_get_neigh
  16. x25_subscr_ioctl
  17. x25_link_free

/*
 *      X.25 Packet Layer release 002
 *
 *      This is ALPHA test software. This code may break your machine,
 *      randomly fail to work with new releases, misbehave and/or generally
 *      screw up. It might even work.
 *
 *      This code REQUIRES 2.1.15 or higher
 *
 *      This module:
 *              This module is free software; you can redistribute it and/or
 *              modify it under the terms of the GNU General Public License
 *              as published by the Free Software Foundation; either version
 *              2 of the License, or (at your option) any later version.
 *
 *      History
 *      X.25 001        Jonathan Naylor   Started coding.
 *      X.25 002        Jonathan Naylor   New timer architecture.
 *      mar/20/00       Daniela Squassoni Disabling/enabling of facilities
 *                                        negotiation.
 *      2000-09-04      Henner Eisen      dev_hold() / dev_put() for x25_neigh.
 */

#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <asm/uaccess.h>
#include <linux/init.h>
#include <net/x25.h>

static LIST_HEAD(x25_neigh_list);
static DEFINE_RWLOCK(x25_neigh_list_lock);

static void x25_t20timer_expiry(unsigned long);

static void x25_transmit_restart_confirmation(struct x25_neigh *nb);
static void x25_transmit_restart_request(struct x25_neigh *nb);

/*
 *      Linux set/reset timer routines
 */
static inline void x25_start_t20timer(struct x25_neigh *nb)
{
        mod_timer(&nb->t20timer, jiffies + nb->t20);
}

static void x25_t20timer_expiry(unsigned long param)
{
        struct x25_neigh *nb = (struct x25_neigh *)param;

        x25_transmit_restart_request(nb);

        x25_start_t20timer(nb);
}

static inline void x25_stop_t20timer(struct x25_neigh *nb)
{
        del_timer(&nb->t20timer);
}

static inline int x25_t20timer_pending(struct x25_neigh *nb)
{
        return timer_pending(&nb->t20timer);
}

/*
 *      This handles all restart and diagnostic frames.
 */
void x25_link_control(struct sk_buff *skb, struct x25_neigh *nb,
                      unsigned short frametype)
{
        struct sk_buff *skbn;
        int confirm;

        switch (frametype) {
                case X25_RESTART_REQUEST:
                        confirm = !x25_t20timer_pending(nb);
                        x25_stop_t20timer(nb);
                        nb->state = X25_LINK_STATE_3;
                        if (confirm)
                                x25_transmit_restart_confirmation(nb);
                        break;

                case X25_RESTART_CONFIRMATION:
                        x25_stop_t20timer(nb);
                        nb->state = X25_LINK_STATE_3;
                        break;

                case X25_DIAGNOSTIC:
                        printk(KERN_WARNING "x25: diagnostic #%d - "
                               "%02X %02X %02X\n",
                               skb->data[3], skb->data[4],
                               skb->data[5], skb->data[6]);
                        break;

                default:
                        printk(KERN_WARNING "x25: received unknown %02X "
                               "with LCI 000\n", frametype);
                        break;
        }

        if (nb->state == X25_LINK_STATE_3)
                while ((skbn = skb_dequeue(&nb->queue)) != NULL)
                        x25_send_frame(skbn, nb);
}

/*
 *      This routine is called when a Restart Request is needed
 */
static void x25_transmit_restart_request(struct x25_neigh *nb)
{
        unsigned char *dptr;
        int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
        struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);

        if (!skb)
                return;

        skb_reserve(skb, X25_MAX_L2_LEN);

        dptr = skb_put(skb, X25_STD_MIN_LEN + 2);

        *dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
        *dptr++ = 0x00;
        *dptr++ = X25_RESTART_REQUEST;
        *dptr++ = 0x00;
        *dptr++ = 0;

        skb->sk = NULL;

        x25_send_frame(skb, nb);
}

/*
 * This routine is called when a Restart Confirmation is needed
 */
static void x25_transmit_restart_confirmation(struct x25_neigh *nb)
{
        unsigned char *dptr;
        int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN;
        struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);

        if (!skb)
                return;

        skb_reserve(skb, X25_MAX_L2_LEN);

        dptr = skb_put(skb, X25_STD_MIN_LEN);

        *dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
        *dptr++ = 0x00;
        *dptr++ = X25_RESTART_CONFIRMATION;

        skb->sk = NULL;

        x25_send_frame(skb, nb);
}

/*
 *      This routine is called when a Clear Request is needed outside of the context
 *      of a connected socket.
 */
void x25_transmit_clear_request(struct x25_neigh *nb, unsigned int lci,
                                unsigned char cause)
{
        unsigned char *dptr;
        int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
        struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);

        if (!skb)
                return;

        skb_reserve(skb, X25_MAX_L2_LEN);

        dptr = skb_put(skb, X25_STD_MIN_LEN + 2);

        *dptr++ = ((lci >> 8) & 0x0F) | (nb->extended ?
                                         X25_GFI_EXTSEQ :
                                         X25_GFI_STDSEQ);
        *dptr++ = (lci >> 0) & 0xFF;
        *dptr++ = X25_CLEAR_REQUEST;
        *dptr++ = cause;
        *dptr++ = 0x00;

        skb->sk = NULL;

        x25_send_frame(skb, nb);
}

void x25_transmit_link(struct sk_buff *skb, struct x25_neigh *nb)
{
        switch (nb->state) {
                case X25_LINK_STATE_0:
                        skb_queue_tail(&nb->queue, skb);
                        nb->state = X25_LINK_STATE_1;
                        x25_establish_link(nb);
                        break;
                case X25_LINK_STATE_1:
                case X25_LINK_STATE_2:
                        skb_queue_tail(&nb->queue, skb);
                        break;
                case X25_LINK_STATE_3:
                        x25_send_frame(skb, nb);
                        break;
        }
}

/*
 *      Called when the link layer has become established.
 */
void x25_link_established(struct x25_neigh *nb)
{
        switch (nb->state) {
                case X25_LINK_STATE_0:
                        nb->state = X25_LINK_STATE_2;
                        break;
                case X25_LINK_STATE_1:
                        x25_transmit_restart_request(nb);
                        nb->state = X25_LINK_STATE_2;
                        x25_start_t20timer(nb);
                        break;
        }
}

/*
 *      Called when the link layer has terminated, or an establishment
 *      request has failed.
 */

void x25_link_terminated(struct x25_neigh *nb)
{
        nb->state = X25_LINK_STATE_0;
        /* Out of order: clear existing virtual calls (X.25 03/93 4.6.3) */
        x25_kill_by_neigh(nb);
}

/*
 *      Add a new device.
 */
void x25_link_device_up(struct net_device *dev)
{
        struct x25_neigh *nb = kmalloc(sizeof(*nb), GFP_ATOMIC);

        if (!nb)
                return;

        skb_queue_head_init(&nb->queue);
        setup_timer(&nb->t20timer, x25_t20timer_expiry, (unsigned long)nb);

        dev_hold(dev);
        nb->dev      = dev;
        nb->state    = X25_LINK_STATE_0;
        nb->extended = 0;
        /*
         * Enables negotiation
         */
        nb->global_facil_mask = X25_MASK_REVERSE |
                                       X25_MASK_THROUGHPUT |
                                       X25_MASK_PACKET_SIZE |
                                       X25_MASK_WINDOW_SIZE;
        nb->t20      = sysctl_x25_restart_request_timeout;
        atomic_set(&nb->refcnt, 1);

        write_lock_bh(&x25_neigh_list_lock);
        list_add(&nb->node, &x25_neigh_list);
        write_unlock_bh(&x25_neigh_list_lock);
}

/**
 *      __x25_remove_neigh - remove neighbour from x25_neigh_list
 *      @nb - neigh to remove
 *
 *      Remove neighbour from x25_neigh_list. If it was there.
 *      Caller must hold x25_neigh_list_lock.
 */
static void __x25_remove_neigh(struct x25_neigh *nb)
{
        skb_queue_purge(&nb->queue);
        x25_stop_t20timer(nb);

        if (nb->node.next) {
                list_del(&nb->node);
                x25_neigh_put(nb);
        }
}

/*
 *      A device has been removed, remove its links.
 */
void x25_link_device_down(struct net_device *dev)
{
        struct x25_neigh *nb;
        struct list_head *entry, *tmp;

        write_lock_bh(&x25_neigh_list_lock);

        list_for_each_safe(entry, tmp, &x25_neigh_list) {
                nb = list_entry(entry, struct x25_neigh, node);

                if (nb->dev == dev) {
                        __x25_remove_neigh(nb);
                        dev_put(dev);
                }
        }

        write_unlock_bh(&x25_neigh_list_lock);
}

/*
 *      Given a device, return the neighbour address.
 */
struct x25_neigh *x25_get_neigh(struct net_device *dev)
{
        struct x25_neigh *nb, *use = NULL;
        struct list_head *entry;

        read_lock_bh(&x25_neigh_list_lock);
        list_for_each(entry, &x25_neigh_list) {
                nb = list_entry(entry, struct x25_neigh, node);

                if (nb->dev == dev) {
                        use = nb;
                        break;
                }
        }

        if (use)
                x25_neigh_hold(use);
        read_unlock_bh(&x25_neigh_list_lock);
        return use;
}

/*
 *      Handle the ioctls that control the subscription functions.
 */
int x25_subscr_ioctl(unsigned int cmd, void __user *arg)
{
        struct x25_subscrip_struct x25_subscr;
        struct x25_neigh *nb;
        struct net_device *dev;
        int rc = -EINVAL;

        if (cmd != SIOCX25GSUBSCRIP && cmd != SIOCX25SSUBSCRIP)
                goto out;

        rc = -EFAULT;
        if (copy_from_user(&x25_subscr, arg, sizeof(x25_subscr)))
                goto out;

        rc = -EINVAL;
        if ((dev = x25_dev_get(x25_subscr.device)) == NULL)
                goto out;

        if ((nb = x25_get_neigh(dev)) == NULL)
                goto out_dev_put;

        dev_put(dev);

        if (cmd == SIOCX25GSUBSCRIP) {
                x25_subscr.extended          = nb->extended;
                x25_subscr.global_facil_mask = nb->global_facil_mask;
                rc = copy_to_user(arg, &x25_subscr,
                                  sizeof(x25_subscr)) ? -EFAULT : 0;
        } else {
                rc = -EINVAL;
                if (!(x25_subscr.extended && x25_subscr.extended != 1)) {
                        rc = 0;
                        nb->extended         = x25_subscr.extended;
                        nb->global_facil_mask = x25_subscr.global_facil_mask;
                }
        }
        x25_neigh_put(nb);
out:
        return rc;
out_dev_put:
        dev_put(dev);
        goto out;
}


/*
 *      Release all memory associated with X.25 neighbour structures.
 */
void __exit x25_link_free(void)
{
        struct x25_neigh *nb;
        struct list_head *entry, *tmp;

        write_lock_bh(&x25_neigh_list_lock);

        list_for_each_safe(entry, tmp, &x25_neigh_list) {
                nb = list_entry(entry, struct x25_neigh, node);
                __x25_remove_neigh(nb);
        }
        write_unlock_bh(&x25_neigh_list_lock);
}

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