// SPDX-License-Identifier: GPL-2.0-only
/*
* Generic HDLC support routines for Linux
* X.25 support
*
* Copyright (C) 1999 - 2006 Krzysztof Halasa <[email protected]>
*/
#include <linux/errno.h>
#include <linux/gfp.h>
#include <linux/hdlc.h>
#include <linux/if_arp.h>
#include <linux/inetdevice.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/lapb.h>
#include <linux/module.h>
#include <linux/pkt_sched.h>
#include <linux/poll.h>
#include <linux/rtnetlink.h>
#include <linux/skbuff.h>
#include <net/x25device.h>
struct x25_state {
x25_hdlc_proto settings;
bool up;
spinlock_t up_lock; /* Protects "up" */
struct sk_buff_head rx_queue;
struct tasklet_struct rx_tasklet;
};
static int x25_ioctl(struct net_device *dev, struct if_settings *ifs);
static struct x25_state *state(hdlc_device *hdlc)
{
return hdlc->state;
}
static void x25_rx_queue_kick(struct tasklet_struct *t)
{
struct x25_state *x25st = from_tasklet(x25st, t, rx_tasklet);
struct sk_buff *skb = skb_dequeue(&x25st->rx_queue);
while (skb) {
netif_receive_skb_core(skb);
skb = skb_dequeue(&x25st->rx_queue);
}
}
/* These functions are callbacks called by LAPB layer */
static void x25_connect_disconnect(struct net_device *dev, int reason, int code)
{
struct x25_state *x25st = state(dev_to_hdlc(dev));
struct sk_buff *skb;
unsigned char *ptr;
skb = __dev_alloc_skb(1, GFP_ATOMIC | __GFP_NOMEMALLOC);
if (!skb)
return;
ptr = skb_put(skb, 1);
*ptr = code;
skb->protocol = x25_type_trans(skb, dev);
skb_queue_tail(&x25st->rx_queue, skb);
tasklet_schedule(&x25st->rx_tasklet);
}
static void x25_connected(struct net_device *dev, int reason)
{
x25_connect_disconnect(dev, reason, X25_IFACE_CONNECT);
}
static void x25_disconnected(struct net_device *dev, int reason)
{
x25_connect_disconnect(dev, reason, X25_IFACE_DISCONNECT);
}
static int x25_data_indication(struct net_device *dev, struct sk_buff *skb)
{
struct x25_state *x25st = state(dev_to_hdlc(dev));
unsigned char *ptr;
if (skb_cow(skb, 1)) {
kfree_skb(skb);
return NET_RX_DROP;
}
skb_push(skb, 1);
ptr = skb->data;
*ptr = X25_IFACE_DATA;
skb->protocol = x25_type_trans(skb, dev);
skb_queue_tail(&x25st->rx_queue, skb);
tasklet_schedule(&x25st->rx_tasklet);
return NET_RX_SUCCESS;
}
static void x25_data_transmit(struct net_device *dev, struct sk_buff *skb)
{
hdlc_device *hdlc = dev_to_hdlc(dev);
skb_reset_network_header(skb);
skb->protocol = hdlc_type_trans(skb, dev);
if (dev_nit_active(dev))
dev_queue_xmit_nit(skb, dev);
hdlc->xmit(skb, dev); /* Ignore return value :-( */
}
static netdev_tx_t x25_xmit(struct sk_buff *skb, struct net_device *dev)
{
hdlc_device *hdlc = dev_to_hdlc(dev);
struct x25_state *x25st = state(hdlc);
int result;
/* There should be a pseudo header of 1 byte added by upper layers.
* Check to make sure it is there before reading it.
*/
if (skb->len < 1) {
kfree_skb(skb);
return NETDEV_TX_OK;
}
spin_lock_bh(&x25st->up_lock);
if (!x25st->up) {
spin_unlock_bh(&x25st->up_lock);
kfree_skb(skb);
return NETDEV_TX_OK;
}
switch (skb->data[0]) {
case X25_IFACE_DATA: /* Data to be transmitted */
skb_pull(skb, 1);
result = lapb_data_request(dev, skb);
if (result != LAPB_OK)
dev_kfree_skb(skb);
spin_unlock_bh(&x25st->up_lock);
return NETDEV_TX_OK;
case X25_IFACE_CONNECT:
result = lapb_connect_request(dev);
if (result != LAPB_OK) {
if (result == LAPB_CONNECTED)
/* Send connect confirm. msg to level 3 */
x25_connected(dev, 0);
else
netdev_err(dev, "LAPB connect request failed, error code = %i\n",
result);
}
break;
case X25_IFACE_DISCONNECT:
result = lapb_disconnect_request(dev);
if (result != LAPB_OK) {
if (result == LAPB_NOTCONNECTED)
/* Send disconnect confirm. msg to level 3 */
x25_disconnected(dev, 0);
else
netdev_err(dev, "LAPB disconnect request failed, error code = %i\n",
result);
}
break;
default: /* to be defined */
break;
}
spin_unlock_bh(&x25st->up_lock);
dev_kfree_skb(skb);
return NETDEV_TX_OK;
}
static int x25_open(struct net_device *dev)
{
static const struct lapb_register_struct cb = {
.connect_confirmation = x25_connected,
.connect_indication = x25_connected,
.disconnect_confirmation = x25_disconnected,
.disconnect_indication = x25_disconnected,
.data_indication = x25_data_indication,
.data_transmit = x25_data_transmit,
};
hdlc_device *hdlc = dev_to_hdlc(dev);
struct x25_state *x25st = state(hdlc);
struct lapb_parms_struct params;
int result;
result = lapb_register(dev, &cb);
if (result != LAPB_OK)
return -ENOMEM;
result = lapb_getparms(dev, ¶ms);
if (result != LAPB_OK)
return -EINVAL;
if (state(hdlc)->settings.dce)
params.mode = params.mode | LAPB_DCE;
if (state(hdlc)->settings.modulo == 128)
params.mode = params.mode | LAPB_EXTENDED;
params.window = state(hdlc)->settings.window;
params.t1 = state(hdlc)->settings.t1;
params.t2 = state(hdlc)->settings.t2;
params.n2 = state(hdlc)->settings.n2;
result = lapb_setparms(dev, ¶ms);
if (result != LAPB_OK)
return -EINVAL;
spin_lock_bh(&x25st->up_lock);
x25st->up = true;
spin_unlock_bh(&x25st->up_lock);
return 0;
}
static void x25_close(struct net_device *dev)
{
hdlc_device *hdlc = dev_to_hdlc(dev);
struct x25_state *x25st = state(hdlc);
spin_lock_bh(&x25st->up_lock);
x25st->up = false;
spin_unlock_bh(&x25st->up_lock);
lapb_unregister(dev);
tasklet_kill(&x25st->rx_tasklet);
}
static int x25_rx(struct sk_buff *skb)
{
struct net_device *dev = skb->dev;
hdlc_device *hdlc = dev_to_hdlc(dev);
struct x25_state *x25st = state(hdlc);
skb = skb_share_check(skb, GFP_ATOMIC);
if (!skb) {
dev->stats.rx_dropped++;
return NET_RX_DROP;
}
spin_lock_bh(&x25st->up_lock);
if (!x25st->up) {
spin_unlock_bh(&x25st->up_lock);
kfree_skb(skb);
dev->stats.rx_dropped++;
return NET_RX_DROP;
}
if (lapb_data_received(dev, skb) == LAPB_OK) {
spin_unlock_bh(&x25st->up_lock);
return NET_RX_SUCCESS;
}
spin_unlock_bh(&x25st->up_lock);
dev->stats.rx_errors++;
dev_kfree_skb_any(skb);
return NET_RX_DROP;
}
static struct hdlc_proto proto = {
.open = x25_open,
.close = x25_close,
.ioctl = x25_ioctl,
.netif_rx = x25_rx,
.xmit = x25_xmit,
.module = THIS_MODULE,
};
static int x25_ioctl(struct net_device *dev, struct if_settings *ifs)
{
x25_hdlc_proto __user *x25_s = ifs->ifs_ifsu.x25;
const size_t size = sizeof(x25_hdlc_proto);
hdlc_device *hdlc = dev_to_hdlc(dev);
x25_hdlc_proto new_settings;
int result;
switch (ifs->type) {
case IF_GET_PROTO:
if (dev_to_hdlc(dev)->proto != &proto)
return -EINVAL;
ifs->type = IF_PROTO_X25;
if (ifs->size < size) {
ifs->size = size; /* data size wanted */
return -ENOBUFS;
}
if (copy_to_user(x25_s, &state(hdlc)->settings, size))
return -EFAULT;
return 0;
case IF_PROTO_X25:
if (!capable(CAP_NET_ADMIN))
return -EPERM;
if (dev->flags & IFF_UP)
return -EBUSY;
/* backward compatibility */
if (ifs->size == 0) {
new_settings.dce = 0;
new_settings.modulo = 8;
new_settings.window = 7;
new_settings.t1 = 3;
new_settings.t2 = 1;
new_settings.n2 = 10;
} else {
if (copy_from_user(&new_settings, x25_s, size))
return -EFAULT;
if ((new_settings.dce != 0 &&
new_settings.dce != 1) ||
(new_settings.modulo != 8 &&
new_settings.modulo != 128) ||
new_settings.window < 1 ||
(new_settings.modulo == 8 &&
new_settings.window > 7) ||
(new_settings.modulo == 128 &&
new_settings.window > 127) ||
new_settings.t1 < 1 ||
new_settings.t1 > 255 ||
new_settings.t2 < 1 ||
new_settings.t2 > 255 ||
new_settings.n2 < 1 ||
new_settings.n2 > 255)
return -EINVAL;
}
result = hdlc->attach(dev, ENCODING_NRZ,
PARITY_CRC16_PR1_CCITT);
if (result)
return result;
result = attach_hdlc_protocol(dev, &proto,
sizeof(struct x25_state));
if (result)
return result;
memcpy(&state(hdlc)->settings, &new_settings, size);
state(hdlc)->up = false;
spin_lock_init(&state(hdlc)->up_lock);
skb_queue_head_init(&state(hdlc)->rx_queue);
tasklet_setup(&state(hdlc)->rx_tasklet, x25_rx_queue_kick);
/* There's no header_ops so hard_header_len should be 0. */
dev->hard_header_len = 0;
/* When transmitting data:
* first we'll remove a pseudo header of 1 byte,
* then we'll prepend an LAPB header of at most 3 bytes.
*/
dev->needed_headroom = 3 - 1;
dev->type = ARPHRD_X25;
call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
netif_dormant_off(dev);
return 0;
}
return -EINVAL;
}
static int __init hdlc_x25_init(void)
{
register_hdlc_protocol(&proto);
return 0;
}
static void __exit hdlc_x25_exit(void)
{
unregister_hdlc_protocol(&proto);
}
module_init(hdlc_x25_init);
module_exit(hdlc_x25_exit);
MODULE_AUTHOR("Krzysztof Halasa <[email protected]>");
MODULE_DESCRIPTION("X.25 protocol support for generic HDLC");
MODULE_LICENSE("GPL v2");
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