From eb2a2fd91f7c8a53b15063d6f08cf22b9a56cbfb Mon Sep 17 00:00:00 2001 From: Krzysztof Halasa Date: Tue, 26 Sep 2006 23:23:45 +0200 Subject: [PATCH] Modularize generic HDLC This patch enables building of individual WAN protocol support routines (parts of generic HDLC) as separate modules. All protocol-private definitions are moved from hdlc.h file to protocol drivers. User-space interface and interface between generic HDLC and underlying low-level HDLC drivers are unchanged. Signed-off-by: Krzysztof Halasa Signed-off-by: Jeff Garzik --- drivers/net/wan/hdlc.c | 368 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 368 insertions(+) create mode 100644 drivers/net/wan/hdlc.c (limited to 'drivers/net/wan/hdlc.c') diff --git a/drivers/net/wan/hdlc.c b/drivers/net/wan/hdlc.c new file mode 100644 index 000000000000..db354e0edbe5 --- /dev/null +++ b/drivers/net/wan/hdlc.c @@ -0,0 +1,368 @@ +/* + * Generic HDLC support routines for Linux + * + * Copyright (C) 1999 - 2006 Krzysztof Halasa + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of version 2 of the GNU General Public License + * as published by the Free Software Foundation. + * + * 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. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + + +static const char* version = "HDLC support module revision 1.20"; + +#undef DEBUG_LINK + +static struct hdlc_proto *first_proto = NULL; + + +static int hdlc_change_mtu(struct net_device *dev, int new_mtu) +{ + if ((new_mtu < 68) || (new_mtu > HDLC_MAX_MTU)) + return -EINVAL; + dev->mtu = new_mtu; + return 0; +} + + + +static struct net_device_stats *hdlc_get_stats(struct net_device *dev) +{ + return hdlc_stats(dev); +} + + + +static int hdlc_rcv(struct sk_buff *skb, struct net_device *dev, + struct packet_type *p, struct net_device *orig_dev) +{ + struct hdlc_device_desc *desc = dev_to_desc(dev); + if (desc->netif_rx) + return desc->netif_rx(skb); + + desc->stats.rx_dropped++; /* Shouldn't happen */ + dev_kfree_skb(skb); + return NET_RX_DROP; +} + + + +static inline void hdlc_proto_start(struct net_device *dev) +{ + hdlc_device *hdlc = dev_to_hdlc(dev); + if (hdlc->proto->start) + return 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) + return hdlc->proto->stop(dev); +} + + + +static int hdlc_device_event(struct notifier_block *this, unsigned long event, + void *ptr) +{ + struct net_device *dev = ptr; + hdlc_device *hdlc; + unsigned long flags; + int on; + + if (dev->get_stats != hdlc_get_stats) + return NOTIFY_DONE; /* not an HDLC device */ + + if (event != NETDEV_CHANGE) + return NOTIFY_DONE; /* Only interrested 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) { + printk(KERN_INFO "%s: Carrier detected\n", dev->name); + hdlc_proto_start(dev); + } else { + printk(KERN_INFO "%s: Carrier lost\n", dev->name); + 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) { + printk(KERN_INFO "%s: Carrier detected\n", dev->name); + hdlc_proto_start(dev); + } else + printk(KERN_INFO "%s: No carrier\n", dev->name); + + 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; +} + +void hdlc_setup(struct net_device *dev) +{ + hdlc_device *hdlc = dev_to_hdlc(dev); + + dev->get_stats = hdlc_get_stats; + dev->change_mtu = hdlc_change_mtu; + dev->mtu = HDLC_MAX_MTU; + + dev->type = ARPHRD_RAWHDLC; + dev->hard_header_len = 16; + + dev->flags = IFF_POINTOPOINT | IFF_NOARP; + + 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_desc) + + sizeof(hdlc_device), "hdlc%d", hdlc_setup); + if (dev) + dev_to_hdlc(dev)->priv = priv; + return dev; +} + +void unregister_hdlc_device(struct net_device *dev) +{ + rtnl_lock(); + unregister_netdevice(dev); + detach_hdlc_protocol(dev); + rtnl_unlock(); +} + + + +int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto, + int (*rx)(struct sk_buff *skb), size_t size) +{ + detach_hdlc_protocol(dev); + + if (!try_module_get(proto->module)) + return -ENOSYS; + + if (size) + if ((dev_to_hdlc(dev)->state = kmalloc(size, + GFP_KERNEL)) == NULL) { + printk(KERN_WARNING "Memory squeeze on" + " hdlc_proto_attach()\n"); + module_put(proto->module); + return -ENOBUFS; + } + dev_to_hdlc(dev)->proto = proto; + dev_to_desc(dev)->netif_rx = rx; + return 0; +} + + +void detach_hdlc_protocol(struct net_device *dev) +{ + hdlc_device *hdlc = dev_to_hdlc(dev); + + if (hdlc->proto) { + if (hdlc->proto->detach) + hdlc->proto->detach(dev); + module_put(hdlc->proto->module); + hdlc->proto = NULL; + } + kfree(hdlc->state); + hdlc->state = NULL; +} + + +void register_hdlc_protocol(struct hdlc_proto *proto) +{ + proto->next = first_proto; + first_proto = proto; +} + + +void unregister_hdlc_protocol(struct hdlc_proto *proto) +{ + struct hdlc_proto **p = &first_proto; + while (*p) { + if (*p == proto) { + *p = proto->next; + return; + } + p = &((*p)->next); + } +} + + + +MODULE_AUTHOR("Krzysztof Halasa "); +MODULE_DESCRIPTION("HDLC support module"); +MODULE_LICENSE("GPL v2"); + +EXPORT_SYMBOL(hdlc_open); +EXPORT_SYMBOL(hdlc_close); +EXPORT_SYMBOL(hdlc_ioctl); +EXPORT_SYMBOL(hdlc_setup); +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 = { + .type = __constant_htons(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; + + printk(KERN_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); -- cgit v1.2.3