rose_loopback.c

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/*
 * This program 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.
 *
 * Copyright (C) Jonathan Naylor G4KLX ([email protected])
 */
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/socket.h>
#include <linux/timer.h>
#include <net/ax25.h>
#include <linux/skbuff.h>
#include <net/rose.h>
#include <linux/init.h>

static struct sk_buff_head loopback_queue;
static struct timer_list loopback_timer;

static void rose_set_loopback_timer(void);

void rose_loopback_init(void)
{
    skb_queue_head_init(&loopback_queue);

    init_timer(&loopback_timer);
}

static int rose_loopback_running(void)
{
    return timer_pending(&loopback_timer);
}

int rose_loopback_queue(struct sk_buff *skb, struct rose_neigh *neigh)
{
    struct sk_buff *skbn;

    skbn = skb_clone(skb, GFP_ATOMIC);

    kfree_skb(skb);

    if (skbn != NULL) {
        skb_queue_tail(&loopback_queue, skbn);

        if (!rose_loopback_running())
            rose_set_loopback_timer();
    }

    return 1;
}

static void rose_loopback_timer(unsigned long);

static void rose_set_loopback_timer(void)
{
    del_timer(&loopback_timer);

    loopback_timer.data     = 0;
    loopback_timer.function = &rose_loopback_timer;
    loopback_timer.expires  = jiffies + 10;

    add_timer(&loopback_timer);
}

static void rose_loopback_timer(unsigned long param)
{
    struct sk_buff *skb;
    struct net_device *dev;
    rose_address *dest;
    struct sock *sk;
    unsigned short frametype;
    unsigned int lci_i, lci_o;

    while ((skb = skb_dequeue(&loopback_queue)) != NULL) {
        if (skb->len < ROSE_MIN_LEN) {
            kfree_skb(skb);
            continue;
        }
        lci_i     = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF);
        frametype = skb->data[2];
        if (frametype == ROSE_CALL_REQUEST &&
            (skb->len <= ROSE_CALL_REQ_FACILITIES_OFF ||
             skb->data[ROSE_CALL_REQ_ADDR_LEN_OFF] !=
             ROSE_CALL_REQ_ADDR_LEN_VAL)) {
            kfree_skb(skb);
            continue;
        }
        dest      = (rose_address *)(skb->data + ROSE_CALL_REQ_DEST_ADDR_OFF);
        lci_o     = ROSE_DEFAULT_MAXVC + 1 - lci_i;

        skb_reset_transport_header(skb);

        sk = rose_find_socket(lci_o, rose_loopback_neigh);
        if (sk) {
            if (rose_process_rx_frame(sk, skb) == 0)
                kfree_skb(skb);
            continue;
        }

        if (frametype == ROSE_CALL_REQUEST) {
            if ((dev = rose_dev_get(dest)) != NULL) {
                if (rose_rx_call_request(skb, dev, rose_loopback_neigh, lci_o) == 0)
                    kfree_skb(skb);
            } else {
                kfree_skb(skb);
            }
        } else {
            kfree_skb(skb);
        }
    }
}

void __exit rose_loopback_clear(void)
{
    struct sk_buff *skb;

    del_timer(&loopback_timer);

    while ((skb = skb_dequeue(&loopback_queue)) != NULL) {
        skb->sk = NULL;
        kfree_skb(skb);
    }
}