openkylin
/
linux
mirror of https://gitee.com/openkylin/linux.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity
linux/drivers/net/wan/hdlc.c

391 lines
8.0 KiB
C
Raw Blame History

// SPDX-License-Identifier: GPL-2.0-only
/*
* Generic HDLC support routines for Linux
*
* Copyright (C) 1999 - 2008 Krzysztof Halasa <khc@pm.waw.pl>
*
* Currently supported:
* * raw IP-in-HDLC
* * Cisco HDLC
* * Frame Relay with ANSI or CCITT LMI (both user and network side)
* * PPP
* * X.25
*
* Use sethdlc utility to set line parameters, protocol and PVCs
*
* How does it work:
* - proto->open(), close(), start(), stop() calls are serialized.
* The order is: open, [ start, stop ... ] close ...
* - proto->start() and stop() are called with spin_lock_irq held.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/errno.h>
#include <linux/hdlc.h>
#include <linux/if_arp.h>
#include <linux/inetdevice.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/pkt_sched.h>
#include <linux/poll.h>
#include <linux/rtnetlink.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <net/net_namespace.h>
static const char* version = "HDLC support module revision 1.22";
#undef DEBUG_LINK
static struct hdlc_proto *first_proto;
static int hdlc_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *p, struct net_device *orig_dev)
{
struct hdlc_device *hdlc = dev_to_hdlc(dev);
if (!net_eq(dev_net(dev), &init_net)) {
kfree_skb(skb);
return 0;
}
BUG_ON(!hdlc->proto->netif_rx);
return hdlc->proto->netif_rx(skb);
}
netdev_tx_t hdlc_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
hdlc_device *hdlc = dev_to_hdlc(dev);
if (hdlc->proto->xmit)
return hdlc->proto->xmit(skb, dev);
return hdlc->xmit(skb, dev); /* call hardware driver directly */
}
static inline void hdlc_proto_start(struct net_device *dev)
{
hdlc_device *hdlc = dev_to_hdlc(dev);
if (hdlc->proto->start)
hdlc->proto->start(dev);
}
static inline void hdlc_proto_stop(struct net_device *dev)
{
hdlc_device *hdlc = dev_to_hdlc(dev);
if (hdlc->proto->stop)
hdlc->proto->stop(dev);
}
static int hdlc_device_event(struct notifier_block *this, unsigned long event,
void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
hdlc_device *hdlc;
unsigned long flags;
int on;
if (!net_eq(dev_net(dev), &init_net))
return NOTIFY_DONE;
if (!(dev->priv_flags & IFF_WAN_HDLC))
return NOTIFY_DONE; /* not an HDLC device */
if (event != NETDEV_CHANGE)
return NOTIFY_DONE; /* Only interested in carrier changes */
on = netif_carrier_ok(dev);
#ifdef DEBUG_LINK
printk(KERN_DEBUG "%s: hdlc_device_event NETDEV_CHANGE, carrier %i\n",
dev->name, on);
#endif
hdlc = dev_to_hdlc(dev);
spin_lock_irqsave(&hdlc->state_lock, flags);
if (hdlc->carrier == on)
goto carrier_exit; /* no change in DCD line level */
hdlc->carrier = on;
if (!hdlc->open)
goto carrier_exit;
if (hdlc->carrier) {
netdev_info(dev, "Carrier detected\n");
hdlc_proto_start(dev);
} else {
netdev_info(dev, "Carrier lost\n");
hdlc_proto_stop(dev);
}
carrier_exit:
spin_unlock_irqrestore(&hdlc->state_lock, flags);
return NOTIFY_DONE;
}
/* Must be called by hardware driver when HDLC device is being opened */
int hdlc_open(struct net_device *dev)
{
hdlc_device *hdlc = dev_to_hdlc(dev);
#ifdef DEBUG_LINK
printk(KERN_DEBUG "%s: hdlc_open() carrier %i open %i\n", dev->name,
hdlc->carrier, hdlc->open);
#endif
if (hdlc->proto == NULL)
return -ENOSYS; /* no protocol attached */
if (hdlc->proto->open) {
int result = hdlc->proto->open(dev);
if (result)
return result;
}
spin_lock_irq(&hdlc->state_lock);
if (hdlc->carrier) {
netdev_info(dev, "Carrier detected\n");
hdlc_proto_start(dev);
} else
netdev_info(dev, "No carrier\n");
hdlc->open = 1;
spin_unlock_irq(&hdlc->state_lock);
return 0;
}
/* Must be called by hardware driver when HDLC device is being closed */
void hdlc_close(struct net_device *dev)
{
hdlc_device *hdlc = dev_to_hdlc(dev);
#ifdef DEBUG_LINK
printk(KERN_DEBUG "%s: hdlc_close() carrier %i open %i\n", dev->name,
hdlc->carrier, hdlc->open);
#endif
spin_lock_irq(&hdlc->state_lock);
hdlc->open = 0;
if (hdlc->carrier)
hdlc_proto_stop(dev);
spin_unlock_irq(&hdlc->state_lock);
if (hdlc->proto->close)
hdlc->proto->close(dev);
}
int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
struct hdlc_proto *proto = first_proto;
int result;
if (cmd != SIOCWANDEV)
return -EINVAL;
if (dev_to_hdlc(dev)->proto) {
result = dev_to_hdlc(dev)->proto->ioctl(dev, ifr);
if (result != -EINVAL)
return result;
}
/* Not handled by currently attached protocol (if any) */
while (proto) {
if ((result = proto->ioctl(dev, ifr)) != -EINVAL)
return result;
proto = proto->next;
}
return -EINVAL;
}
static const struct header_ops hdlc_null_ops;
static void hdlc_setup_dev(struct net_device *dev)
{
/* Re-init all variables changed by HDLC protocol drivers,
* including ether_setup() called from hdlc_raw_eth.c.
*/
dev->flags = IFF_POINTOPOINT | IFF_NOARP;
dev->priv_flags = IFF_WAN_HDLC;
dev->mtu = HDLC_MAX_MTU;
dev->min_mtu = 68;
dev->max_mtu = HDLC_MAX_MTU;
dev->type = ARPHRD_RAWHDLC;
dev->hard_header_len = 16;
dev->addr_len = 0;
dev->header_ops = &hdlc_null_ops;
}
static void hdlc_setup(struct net_device *dev)
{
hdlc_device *hdlc = dev_to_hdlc(dev);
hdlc_setup_dev(dev);
hdlc->carrier = 1;
hdlc->open = 0;
spin_lock_init(&hdlc->state_lock);
}
struct net_device *alloc_hdlcdev(void *priv)
{
struct net_device *dev;
dev = alloc_netdev(sizeof(struct hdlc_device), "hdlc%d",
NET_NAME_UNKNOWN, hdlc_setup);
if (dev)
dev_to_hdlc(dev)->priv = priv;
return dev;
}
void unregister_hdlc_device(struct net_device *dev)
{
rtnl_lock();
detach_hdlc_protocol(dev);
unregister_netdevice(dev);
rtnl_unlock();
}
int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
size_t size)
{
int err;
err = detach_hdlc_protocol(dev);
if (err)
return err;
if (!try_module_get(proto->module))
return -ENOSYS;
if (size) {
dev_to_hdlc(dev)->state = kmalloc(size, GFP_KERNEL);
if (dev_to_hdlc(dev)->state == NULL) {
module_put(proto->module);
return -ENOBUFS;
}
}
dev_to_hdlc(dev)->proto = proto;
return 0;
}
int detach_hdlc_protocol(struct net_device *dev)
{
hdlc_device *hdlc = dev_to_hdlc(dev);
int err;
if (hdlc->proto) {
err = call_netdevice_notifiers(NETDEV_PRE_TYPE_CHANGE, dev);
err = notifier_to_errno(err);
if (err) {
netdev_err(dev, "Refused to change device type\n");
return err;
}
if (hdlc->proto->detach)
hdlc->proto->detach(dev);
module_put(hdlc->proto->module);
hdlc->proto = NULL;
}
kfree(hdlc->state);
hdlc->state = NULL;
hdlc_setup_dev(dev);
return 0;
}
void register_hdlc_protocol(struct hdlc_proto *proto)
{
rtnl_lock();
proto->next = first_proto;
first_proto = proto;
rtnl_unlock();
}
void unregister_hdlc_protocol(struct hdlc_proto *proto)
{
struct hdlc_proto **p;
rtnl_lock();
p = &first_proto;
while (*p != proto) {
BUG_ON(!*p);
p = &((*p)->next);
}
*p = proto->next;
rtnl_unlock();
}
MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
MODULE_DESCRIPTION("HDLC support module");
MODULE_LICENSE("GPL v2");
EXPORT_SYMBOL(hdlc_start_xmit);
EXPORT_SYMBOL(hdlc_open);
EXPORT_SYMBOL(hdlc_close);
EXPORT_SYMBOL(hdlc_ioctl);
EXPORT_SYMBOL(alloc_hdlcdev);
EXPORT_SYMBOL(unregister_hdlc_device);
EXPORT_SYMBOL(register_hdlc_protocol);
EXPORT_SYMBOL(unregister_hdlc_protocol);
EXPORT_SYMBOL(attach_hdlc_protocol);
EXPORT_SYMBOL(detach_hdlc_protocol);
static struct packet_type hdlc_packet_type __read_mostly = {
.type = cpu_to_be16(ETH_P_HDLC),
.func = hdlc_rcv,
};
static struct notifier_block hdlc_notifier = {
.notifier_call = hdlc_device_event,
};
static int __init hdlc_module_init(void)
{
int result;
pr_info("%s\n", version);
if ((result = register_netdevice_notifier(&hdlc_notifier)) != 0)
return result;
dev_add_pack(&hdlc_packet_type);
return 0;
}
static void __exit hdlc_module_exit(void)
{
dev_remove_pack(&hdlc_packet_type);
unregister_netdevice_notifier(&hdlc_notifier);
}
module_init(hdlc_module_init);
module_exit(hdlc_module_exit);
Reference in New Issue View Git Blame Copy Permalink