linux-imx

/*

 *  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   Centralised disconnection processing.

 *  mar/20/00   Daniela Squassoni Disabling/enabling of facilities

 *                    negotiation.

 *  jun/24/01   Arnaldo C. Melo   use skb_queue_purge, cleanups

 *  apr/04/15   Shaun Pereira       Fast select with no

 *                      restriction on response.

 */

​

#define pr_fmt(fmt) "X25: " fmt

​

#include <linux/slab.h>

#include <linux/kernel.h>

#include <linux/string.h>

#include <linux/skbuff.h>

#include <net/sock.h>

#include <net/tcp_states.h>

#include <net/x25.h>

​

/*

 *  This routine purges all of the queues of frames.

 */

void x25_clear_queues(struct sock *sk)

{

    struct x25_sock *x25 = x25_sk(sk);

​

    skb_queue_purge(&sk->sk_write_queue);

    skb_queue_purge(&x25->ack_queue);

    skb_queue_purge(&x25->interrupt_in_queue);

    skb_queue_purge(&x25->interrupt_out_queue);

    skb_queue_purge(&x25->fragment_queue);

}

​

​

/*

 * This routine purges the input queue of those frames that have been

 * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the

 * SDL diagram.

*/

void x25_frames_acked(struct sock *sk, unsigned short nr)

{

    struct sk_buff *skb;

    struct x25_sock *x25 = x25_sk(sk);

    int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS;

​

    /*

     * Remove all the ack-ed frames from the ack queue.

     */

    if (x25->va != nr)

        while (skb_peek(&x25->ack_queue) && x25->va != nr) {

            skb = skb_dequeue(&x25->ack_queue);

            kfree_skb(skb);

            x25->va = (x25->va + 1) % modulus;

        }

}

​

void x25_requeue_frames(struct sock *sk)

{

    struct sk_buff *skb, *skb_prev = NULL;

​

    /*

     * Requeue all the un-ack-ed frames on the output queue to be picked

     * up by x25_kick. This arrangement handles the possibility of an empty

     * output queue.

     */

    while ((skb = skb_dequeue(&x25_sk(sk)->ack_queue)) != NULL) {

        if (!skb_prev)

            skb_queue_head(&sk->sk_write_queue, skb);

        else

            skb_append(skb_prev, skb, &sk->sk_write_queue);

        skb_prev = skb;

    }

}

​

/*

 *  Validate that the value of nr is between va and vs. Return true or