linux/net/ax25/ax25_ds_subr.c
Thomas Gleixner 2874c5fd28 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152
Based on 1 normalized pattern(s):

  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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:32 -07:00

205 lines
4.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
*
* Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
* Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
*/
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/spinlock.h>
#include <linux/net.h>
#include <linux/gfp.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <linux/uaccess.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
void ax25_ds_nr_error_recovery(ax25_cb *ax25)
{
ax25_ds_establish_data_link(ax25);
}
/*
* dl1bke 960114: transmit I frames on DAMA poll
*/
void ax25_ds_enquiry_response(ax25_cb *ax25)
{
ax25_cb *ax25o;
/* Please note that neither DK4EG's nor DG2FEF's
* DAMA spec mention the following behaviour as seen
* with TheFirmware:
*
* DB0ACH->DL1BKE <RR C P R0> [DAMA]
* DL1BKE->DB0ACH <I NR=0 NS=0>
* DL1BKE-7->DB0PRA-6 DB0ACH <I C S3 R5>
* DL1BKE->DB0ACH <RR R F R0>
*
* The Flexnet DAMA Master implementation apparently
* insists on the "proper" AX.25 behaviour:
*
* DB0ACH->DL1BKE <RR C P R0> [DAMA]
* DL1BKE->DB0ACH <RR R F R0>
* DL1BKE->DB0ACH <I NR=0 NS=0>
* DL1BKE-7->DB0PRA-6 DB0ACH <I C S3 R5>
*
* Flexnet refuses to send us *any* I frame if we send
* a REJ in case AX25_COND_REJECT is set. It is superfluous in
* this mode anyway (a RR or RNR invokes the retransmission).
* Is this a Flexnet bug?
*/
ax25_std_enquiry_response(ax25);
if (!(ax25->condition & AX25_COND_PEER_RX_BUSY)) {
ax25_requeue_frames(ax25);
ax25_kick(ax25);
}
if (ax25->state == AX25_STATE_1 || ax25->state == AX25_STATE_2 || skb_peek(&ax25->ack_queue) != NULL)
ax25_ds_t1_timeout(ax25);
else
ax25->n2count = 0;
ax25_start_t3timer(ax25);
ax25_ds_set_timer(ax25->ax25_dev);
spin_lock(&ax25_list_lock);
ax25_for_each(ax25o, &ax25_list) {
if (ax25o == ax25)
continue;
if (ax25o->ax25_dev != ax25->ax25_dev)
continue;
if (ax25o->state == AX25_STATE_1 || ax25o->state == AX25_STATE_2) {
ax25_ds_t1_timeout(ax25o);
continue;
}
if (!(ax25o->condition & AX25_COND_PEER_RX_BUSY) && ax25o->state == AX25_STATE_3) {
ax25_requeue_frames(ax25o);
ax25_kick(ax25o);
}
if (ax25o->state == AX25_STATE_1 || ax25o->state == AX25_STATE_2 || skb_peek(&ax25o->ack_queue) != NULL)
ax25_ds_t1_timeout(ax25o);
/* do not start T3 for listening sockets (tnx DD8NE) */
if (ax25o->state != AX25_STATE_0)
ax25_start_t3timer(ax25o);
}
spin_unlock(&ax25_list_lock);
}
void ax25_ds_establish_data_link(ax25_cb *ax25)
{
ax25->condition &= AX25_COND_DAMA_MODE;
ax25->n2count = 0;
ax25_calculate_t1(ax25);
ax25_start_t1timer(ax25);
ax25_stop_t2timer(ax25);
ax25_start_t3timer(ax25);
}
/*
* :::FIXME:::
* This is a kludge. Not all drivers recognize kiss commands.
* We need a driver level request to switch duplex mode, that does
* either SCC changing, PI config or KISS as required. Currently
* this request isn't reliable.
*/
static void ax25_kiss_cmd(ax25_dev *ax25_dev, unsigned char cmd, unsigned char param)
{
struct sk_buff *skb;
unsigned char *p;
if (ax25_dev->dev == NULL)
return;
if ((skb = alloc_skb(2, GFP_ATOMIC)) == NULL)
return;
skb_reset_network_header(skb);
p = skb_put(skb, 2);
*p++ = cmd;
*p++ = param;
skb->protocol = ax25_type_trans(skb, ax25_dev->dev);
dev_queue_xmit(skb);
}
/*
* A nasty problem arises if we count the number of DAMA connections
* wrong, especially when connections on the device already existed
* and our network node (or the sysop) decides to turn on DAMA Master
* mode. We thus flag the 'real' slave connections with
* ax25->dama_slave=1 and look on every disconnect if still slave
* connections exist.
*/
static int ax25_check_dama_slave(ax25_dev *ax25_dev)
{
ax25_cb *ax25;
int res = 0;
spin_lock(&ax25_list_lock);
ax25_for_each(ax25, &ax25_list)
if (ax25->ax25_dev == ax25_dev && (ax25->condition & AX25_COND_DAMA_MODE) && ax25->state > AX25_STATE_1) {
res = 1;
break;
}
spin_unlock(&ax25_list_lock);
return res;
}
static void ax25_dev_dama_on(ax25_dev *ax25_dev)
{
if (ax25_dev == NULL)
return;
if (ax25_dev->dama.slave == 0)
ax25_kiss_cmd(ax25_dev, 5, 1);
ax25_dev->dama.slave = 1;
ax25_ds_set_timer(ax25_dev);
}
void ax25_dev_dama_off(ax25_dev *ax25_dev)
{
if (ax25_dev == NULL)
return;
if (ax25_dev->dama.slave && !ax25_check_dama_slave(ax25_dev)) {
ax25_kiss_cmd(ax25_dev, 5, 0);
ax25_dev->dama.slave = 0;
ax25_ds_del_timer(ax25_dev);
}
}
void ax25_dama_on(ax25_cb *ax25)
{
ax25_dev_dama_on(ax25->ax25_dev);
ax25->condition |= AX25_COND_DAMA_MODE;
}
void ax25_dama_off(ax25_cb *ax25)
{
ax25->condition &= ~AX25_COND_DAMA_MODE;
ax25_dev_dama_off(ax25->ax25_dev);
}