[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 <khc@pm.waw.pl>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 134 insertions, 64 deletions

diff --git a/drivers/net/wan/hdlc_cisco.c b/drivers/net/wan/hdlc_cisco.c
index f289daba0c7..7ec2b2f9b7e 100644
--- a/drivers/net/wan/hdlc_cisco.c
+++ b/drivers/net/wan/hdlc_cisco.c
@@ -2,7 +2,7 @@
  * Generic HDLC support routines for Linux
  * Cisco HDLC support
  *
- * Copyright (C) 2000 - 2003 Krzysztof Halasa <khc@pm.waw.pl>
+ * Copyright (C) 2000 - 2006 Krzysztof Halasa <khc@pm.waw.pl>
  *
  * 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
@@ -34,17 +34,56 @@
 #define CISCO_KEEPALIVE_REQ	2	/* Cisco keepalive request */
 
 
+struct hdlc_header {
+	u8 address;
+	u8 control;
+	u16 protocol;
+}__attribute__ ((packed));
+
+
+struct cisco_packet {
+	u32 type;		/* code */
+	u32 par1;
+	u32 par2;
+	u16 rel;		/* reliability */
+	u32 time;
+}__attribute__ ((packed));
+#define	CISCO_PACKET_LEN	18
+#define	CISCO_BIG_PACKET_LEN	20
+
+
+struct cisco_state {
+	cisco_proto settings;
+
+	struct timer_list timer;
+	unsigned long last_poll;
+	int up;
+	int request_sent;
+	u32 txseq; /* TX sequence number */
+	u32 rxseq; /* RX sequence number */
+};
+
+
+static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr);
+
+
+static inline struct cisco_state * state(hdlc_device *hdlc)
+{
+	return(struct cisco_state *)(hdlc->state);
+}
+
+
 static int cisco_hard_header(struct sk_buff *skb, struct net_device *dev,
 			     u16 type, void *daddr, void *saddr,
 			     unsigned int len)
 {
-	hdlc_header *data;
+	struct hdlc_header *data;
 #ifdef DEBUG_HARD_HEADER
 	printk(KERN_DEBUG "%s: cisco_hard_header called\n", dev->name);
 #endif
 
-	skb_push(skb, sizeof(hdlc_header));
-	data = (hdlc_header*)skb->data;
+	skb_push(skb, sizeof(struct hdlc_header));
+	data = (struct hdlc_header*)skb->data;
 	if (type == CISCO_KEEPALIVE)
 		data->address = CISCO_MULTICAST;
 	else
@@ -52,7 +91,7 @@ static int cisco_hard_header(struct sk_buff *skb, struct net_device *dev,
 	data->control = 0;
 	data->protocol = htons(type);
 
-	return sizeof(hdlc_header);
+	return sizeof(struct hdlc_header);
 }
 
 
@@ -61,9 +100,10 @@ static void cisco_keepalive_send(struct net_device *dev, u32 type,
 				 u32 par1, u32 par2)
 {
 	struct sk_buff *skb;
-	cisco_packet *data;
+	struct cisco_packet *data;
 
-	skb = dev_alloc_skb(sizeof(hdlc_header) + sizeof(cisco_packet));
+	skb = dev_alloc_skb(sizeof(struct hdlc_header) +
+			    sizeof(struct cisco_packet));
 	if (!skb) {
 		printk(KERN_WARNING
 		       "%s: Memory squeeze on cisco_keepalive_send()\n",
@@ -72,7 +112,7 @@ static void cisco_keepalive_send(struct net_device *dev, u32 type,
 	}
 	skb_reserve(skb, 4);
 	cisco_hard_header(skb, dev, CISCO_KEEPALIVE, NULL, NULL, 0);
-	data = (cisco_packet*)(skb->data + 4);
+	data = (struct cisco_packet*)(skb->data + 4);
 
 	data->type = htonl(type);
 	data->par1 = htonl(par1);
@@ -81,7 +121,7 @@ static void cisco_keepalive_send(struct net_device *dev, u32 type,
 	/* we will need do_div here if 1000 % HZ != 0 */
 	data->time = htonl((jiffies - INITIAL_JIFFIES) * (1000 / HZ));
 
-	skb_put(skb, sizeof(cisco_packet));
+	skb_put(skb, sizeof(struct cisco_packet));
 	skb->priority = TC_PRIO_CONTROL;
 	skb->dev = dev;
 	skb->nh.raw = skb->data;
@@ -93,9 +133,9 @@ static void cisco_keepalive_send(struct net_device *dev, u32 type,
 
 static __be16 cisco_type_trans(struct sk_buff *skb, struct net_device *dev)
 {
-	hdlc_header *data = (hdlc_header*)skb->data;
+	struct hdlc_header *data = (struct hdlc_header*)skb->data;
 
-	if (skb->len < sizeof(hdlc_header))
+	if (skb->len < sizeof(struct hdlc_header))
 		return __constant_htons(ETH_P_HDLC);
 
 	if (data->address != CISCO_MULTICAST &&
@@ -106,7 +146,7 @@ static __be16 cisco_type_trans(struct sk_buff *skb, struct net_device *dev)
 	case __constant_htons(ETH_P_IP):
 	case __constant_htons(ETH_P_IPX):
 	case __constant_htons(ETH_P_IPV6):
-		skb_pull(skb, sizeof(hdlc_header));
+		skb_pull(skb, sizeof(struct hdlc_header));
 		return data->protocol;
 	default:
 		return __constant_htons(ETH_P_HDLC);
@@ -118,12 +158,12 @@ static int cisco_rx(struct sk_buff *skb)
 {
 	struct net_device *dev = skb->dev;
 	hdlc_device *hdlc = dev_to_hdlc(dev);
-	hdlc_header *data = (hdlc_header*)skb->data;
-	cisco_packet *cisco_data;
+	struct hdlc_header *data = (struct hdlc_header*)skb->data;
+	struct cisco_packet *cisco_data;
 	struct in_device *in_dev;
 	u32 addr, mask;
 
-	if (skb->len < sizeof(hdlc_header))
+	if (skb->len < sizeof(struct hdlc_header))
 		goto rx_error;
 
 	if (data->address != CISCO_MULTICAST &&
@@ -137,15 +177,17 @@ static int cisco_rx(struct sk_buff *skb)
 		return NET_RX_SUCCESS;
 
 	case CISCO_KEEPALIVE:
-		if (skb->len != sizeof(hdlc_header) + CISCO_PACKET_LEN &&
-		    skb->len != sizeof(hdlc_header) + CISCO_BIG_PACKET_LEN) {
-			printk(KERN_INFO "%s: Invalid length of Cisco "
-			       "control packet (%d bytes)\n",
-			       dev->name, skb->len);
+		if ((skb->len != sizeof(struct hdlc_header) +
+		     CISCO_PACKET_LEN) &&
+		    (skb->len != sizeof(struct hdlc_header) +
+		     CISCO_BIG_PACKET_LEN)) {
+			printk(KERN_INFO "%s: Invalid length of Cisco control"
+			       " packet (%d bytes)\n", dev->name, skb->len);
 			goto rx_error;
 		}
 
-		cisco_data = (cisco_packet*)(skb->data + sizeof(hdlc_header));
+		cisco_data = (struct cisco_packet*)(skb->data + sizeof
+						    (struct hdlc_header));
 
 		switch(ntohl (cisco_data->type)) {
 		case CISCO_ADDR_REQ: /* Stolen from syncppp.c :-) */
@@ -178,11 +220,11 @@ static int cisco_rx(struct sk_buff *skb)
 			goto rx_error;
 
 		case CISCO_KEEPALIVE_REQ:
-			hdlc->state.cisco.rxseq = ntohl(cisco_data->par1);
-			if (hdlc->state.cisco.request_sent &&
-			    ntohl(cisco_data->par2)==hdlc->state.cisco.txseq) {
-				hdlc->state.cisco.last_poll = jiffies;
-				if (!hdlc->state.cisco.up) {
+			state(hdlc)->rxseq = ntohl(cisco_data->par1);
+			if (state(hdlc)->request_sent &&
+			    ntohl(cisco_data->par2) == state(hdlc)->txseq) {
+				state(hdlc)->last_poll = jiffies;
+				if (!state(hdlc)->up) {
 					u32 sec, min, hrs, days;
 					sec = ntohl(cisco_data->time) / 1000;
 					min = sec / 60; sec -= min * 60;
@@ -193,7 +235,7 @@ static int cisco_rx(struct sk_buff *skb)
 					       dev->name, days, hrs,
 					       min, sec);
 					netif_dormant_off(dev);
-					hdlc->state.cisco.up = 1;
+					state(hdlc)->up = 1;
 				}
 			}
 
@@ -208,7 +250,7 @@ static int cisco_rx(struct sk_buff *skb)
 	return NET_RX_DROP;
 
  rx_error:
-	hdlc->stats.rx_errors++; /* Mark error */
+	dev_to_desc(dev)->stats.rx_errors++; /* Mark error */
 	dev_kfree_skb_any(skb);
 	return NET_RX_DROP;
 }
@@ -220,23 +262,22 @@ static void cisco_timer(unsigned long arg)
 	struct net_device *dev = (struct net_device *)arg;
 	hdlc_device *hdlc = dev_to_hdlc(dev);
 
-	if (hdlc->state.cisco.up &&
-	    time_after(jiffies, hdlc->state.cisco.last_poll +
-		       hdlc->state.cisco.settings.timeout * HZ)) {
-		hdlc->state.cisco.up = 0;
+	if (state(hdlc)->up &&
+	    time_after(jiffies, state(hdlc)->last_poll +
+		       state(hdlc)->settings.timeout * HZ)) {
+		state(hdlc)->up = 0;
 		printk(KERN_INFO "%s: Link down\n", dev->name);
 		netif_dormant_on(dev);
 	}
 
-	cisco_keepalive_send(dev, CISCO_KEEPALIVE_REQ,
-			     ++hdlc->state.cisco.txseq,
-			     hdlc->state.cisco.rxseq);
-	hdlc->state.cisco.request_sent = 1;
-	hdlc->state.cisco.timer.expires = jiffies +
-		hdlc->state.cisco.settings.interval * HZ;
-	hdlc->state.cisco.timer.function = cisco_timer;
-	hdlc->state.cisco.timer.data = arg;
-	add_timer(&hdlc->state.cisco.timer);
+	cisco_keepalive_send(dev, CISCO_KEEPALIVE_REQ, ++state(hdlc)->txseq,
+			     state(hdlc)->rxseq);
+	state(hdlc)->request_sent = 1;
+	state(hdlc)->timer.expires = jiffies +
+		state(hdlc)->settings.interval * HZ;
+	state(hdlc)->timer.function = cisco_timer;
+	state(hdlc)->timer.data = arg;
+	add_timer(&state(hdlc)->timer);
 }
 
 
@@ -244,15 +285,15 @@ static void cisco_timer(unsigned long arg)
 static void cisco_start(struct net_device *dev)
 {
 	hdlc_device *hdlc = dev_to_hdlc(dev);
-	hdlc->state.cisco.up = 0;
-	hdlc->state.cisco.request_sent = 0;
-	hdlc->state.cisco.txseq = hdlc->state.cisco.rxseq = 0;
-
-	init_timer(&hdlc->state.cisco.timer);
-	hdlc->state.cisco.timer.expires = jiffies + HZ; /*First poll after 1s*/
-	hdlc->state.cisco.timer.function = cisco_timer;
-	hdlc->state.cisco.timer.data = (unsigned long)dev;
-	add_timer(&hdlc->state.cisco.timer);
+	state(hdlc)->up = 0;
+	state(hdlc)->request_sent = 0;
+	state(hdlc)->txseq = state(hdlc)->rxseq = 0;
+
+	init_timer(&state(hdlc)->timer);
+	state(hdlc)->timer.expires = jiffies + HZ; /*First poll after 1s*/
+	state(hdlc)->timer.function = cisco_timer;
+	state(hdlc)->timer.data = (unsigned long)dev;
+	add_timer(&state(hdlc)->timer);
 }
 
 
@@ -260,15 +301,24 @@ static void cisco_start(struct net_device *dev)
 static void cisco_stop(struct net_device *dev)
 {
 	hdlc_device *hdlc = dev_to_hdlc(dev);
-	del_timer_sync(&hdlc->state.cisco.timer);
+	del_timer_sync(&state(hdlc)->timer);
 	netif_dormant_on(dev);
-	hdlc->state.cisco.up = 0;
-	hdlc->state.cisco.request_sent = 0;
+	state(hdlc)->up = 0;
+	state(hdlc)->request_sent = 0;
 }
 
 
 
-int hdlc_cisco_ioctl(struct net_device *dev, struct ifreq *ifr)
+static struct hdlc_proto proto = {
+	.start		= cisco_start,
+	.stop		= cisco_stop,
+	.type_trans	= cisco_type_trans,
+	.ioctl		= cisco_ioctl,
+	.module		= THIS_MODULE,
+};
+ 
+ 
+static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr)
 {
 	cisco_proto __user *cisco_s = ifr->ifr_settings.ifs_ifsu.cisco;
 	const size_t size = sizeof(cisco_proto);
@@ -278,12 +328,14 @@ int hdlc_cisco_ioctl(struct net_device *dev, struct ifreq *ifr)
 
 	switch (ifr->ifr_settings.type) {
 	case IF_GET_PROTO:
+		if (dev_to_hdlc(dev)->proto != &proto)
+			return -EINVAL;
 		ifr->ifr_settings.type = IF_PROTO_CISCO;
 		if (ifr->ifr_settings.size < size) {
 			ifr->ifr_settings.size = size; /* data size wanted */
 			return -ENOBUFS;
 		}
-		if (copy_to_user(cisco_s, &hdlc->state.cisco.settings, size))
+		if (copy_to_user(cisco_s, &state(hdlc)->settings, size))
 			return -EFAULT;
 		return 0;
 
@@ -302,19 +354,15 @@ int hdlc_cisco_ioctl(struct net_device *dev, struct ifreq *ifr)
 			return -EINVAL;
 
 		result=hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
-
 		if (result)
 			return result;
 
-		hdlc_proto_detach(hdlc);
-		memcpy(&hdlc->state.cisco.settings, &new_settings, size);
-		memset(&hdlc->proto, 0, sizeof(hdlc->proto));
+		result = attach_hdlc_protocol(dev, &proto, cisco_rx,
+					      sizeof(struct cisco_state));
+		if (result)
+			return result;
 
-		hdlc->proto.start = cisco_start;
-		hdlc->proto.stop = cisco_stop;
-		hdlc->proto.netif_rx = cisco_rx;
-		hdlc->proto.type_trans = cisco_type_trans;
-		hdlc->proto.id = IF_PROTO_CISCO;
+		memcpy(&state(hdlc)->settings, &new_settings, size);
 		dev->hard_start_xmit = hdlc->xmit;
 		dev->hard_header = cisco_hard_header;
 		dev->hard_header_cache = NULL;
@@ -327,3 +375,25 @@ int hdlc_cisco_ioctl(struct net_device *dev, struct ifreq *ifr)
 
 	return -EINVAL;
 }
+
+
+static int __init mod_init(void)
+{
+	register_hdlc_protocol(&proto);
+	return 0;
+}
+
+
+
+static void __exit mod_exit(void)
+{
+	unregister_hdlc_protocol(&proto);
+}
+
+
+module_init(mod_init);
+module_exit(mod_exit);
+
+MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
+MODULE_DESCRIPTION("Cisco HDLC protocol support for generic HDLC");
+MODULE_LICENSE("GPL v2");