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// SPDX-License-Identifier: GPL-2.0-or-later
/*
*
* Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
*/
#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>
#define ROSE_LOOPBACK_LIMIT 1000
static struct timer_list loopback_timer;
static struct sk_buff_head loopback_queue;
static void rose_set_loopback_timer(void);
static void rose_loopback_timer(struct timer_list *unused);
static atomic_t loopback_stopping = ATOMIC_INIT(0);
void rose_loopback_init(void)
{
skb_queue_head_init(&loopback_queue);
timer_setup(&loopback_timer, rose_loopback_timer, 0);
}
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 = NULL;
if (skb_queue_len(&loopback_queue) < ROSE_LOOPBACK_LIMIT)
skbn = skb_clone(skb, GFP_ATOMIC);
if (skbn) {
consume_skb(skb);
skb_queue_tail(&loopback_queue, skbn);
if (!rose_loopback_running())
rose_set_loopback_timer();
} else {
kfree_skb(skb);
}
return 1;
}
static void rose_set_loopback_timer(void)
{
mod_timer(&loopback_timer, jiffies + 10);
}
static void rose_loopback_timer(struct timer_list *unused)
{
struct sk_buff *skb;
struct net_device *dev;
rose_address *dest;
struct sock *sk;
unsigned short frametype;
unsigned int lci_i, lci_o;
int count;
if (atomic_read(&loopback_stopping))
return;
if (rose_loopback_neigh)
rose_neigh_hold(rose_loopback_neigh);
else
return;
for (count = 0; count < ROSE_LOOPBACK_LIMIT; count++) {
skb = skb_dequeue(&loopback_queue);
if (!skb)
goto out;
if (atomic_read(&loopback_stopping)) {
kfree_skb(skb);
skb_queue_purge(&loopback_queue);
goto out;
}
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) {
dev = rose_dev_get(dest);
if (!dev) {
kfree_skb(skb);
continue;
}
/* rose_kill_by_device() runs on NETDEV_DOWN (IFF_UP cleared)
* before the device is unregistered. If we create a new
* socket here after that cleanup, the ref never gets released
* because NETDEV_DOWN fires only once. Drop the call instead.
*/
if (!netif_running(dev)) {
dev_put(dev);
kfree_skb(skb);
continue;
}
if (rose_rx_call_request(skb, dev, rose_loopback_neigh, lci_o) == 0)
kfree_skb(skb);
dev_put(dev);
} else {
kfree_skb(skb);
}
}
out:
rose_neigh_put(rose_loopback_neigh);
if (!atomic_read(&loopback_stopping) && !skb_queue_empty(&loopback_queue))
mod_timer(&loopback_timer, jiffies + 1);
}
void __exit rose_loopback_clear(void)
{
struct sk_buff *skb;
atomic_set(&loopback_stopping, 1);
/* Pairs with atomic_read() in rose_loopback_timer(): ensure the
* stopping flag is visible before we cancel, so a concurrent
* callback aborts its loop early rather than re-arming the timer.
*/
smp_mb();
timer_delete_sync(&loopback_timer);
while ((skb = skb_dequeue(&loopback_queue)) != NULL)
kfree_skb(skb);
}
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