[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>

2 files changed, 77 insertions, 157 deletions

diff --git a/include/linux/hdlc.h b/include/linux/hdlc.h
index d5ebbb29aeae..d4b333938f73 100644
--- a/include/linux/hdlc.h
+++ b/include/linux/hdlc.h
@@ -11,95 +11,46 @@
 #ifndef __HDLC_H
 #define __HDLC_H
 
-#define GENERIC_HDLC_VERSION 4	/* For synchronization with sethdlc utility */
-
-#define CLOCK_DEFAULT   0	/* Default setting */
-#define CLOCK_EXT	1	/* External TX and RX clock - DTE */
-#define CLOCK_INT	2	/* Internal TX and RX clock - DCE */
-#define CLOCK_TXINT	3	/* Internal TX and external RX clock */
-#define CLOCK_TXFROMRX	4	/* TX clock derived from external RX clock */
-
-
-#define ENCODING_DEFAULT	0 /* Default setting */
-#define ENCODING_NRZ		1
-#define ENCODING_NRZI		2
-#define ENCODING_FM_MARK	3
-#define ENCODING_FM_SPACE	4
-#define ENCODING_MANCHESTER	5
-
-
-#define PARITY_DEFAULT		0 /* Default setting */
-#define PARITY_NONE		1 /* No parity */
-#define PARITY_CRC16_PR0	2 /* CRC16, initial value 0x0000 */
-#define PARITY_CRC16_PR1	3 /* CRC16, initial value 0xFFFF */
-#define PARITY_CRC16_PR0_CCITT	4 /* CRC16, initial 0x0000, ITU-T version */
-#define PARITY_CRC16_PR1_CCITT	5 /* CRC16, initial 0xFFFF, ITU-T version */
-#define PARITY_CRC32_PR0_CCITT	6 /* CRC32, initial value 0x00000000 */
-#define PARITY_CRC32_PR1_CCITT	7 /* CRC32, initial value 0xFFFFFFFF */
-
-#define LMI_DEFAULT		0 /* Default setting */
-#define LMI_NONE		1 /* No LMI, all PVCs are static */
-#define LMI_ANSI		2 /* ANSI Annex D */
-#define LMI_CCITT		3 /* ITU-T Annex A */
-#define LMI_CISCO		4 /* The "original" LMI, aka Gang of Four */
 
 #define HDLC_MAX_MTU 1500	/* Ethernet 1500 bytes */
+#if 0
 #define HDLC_MAX_MRU (HDLC_MAX_MTU + 10 + 14 + 4) /* for ETH+VLAN over FR */
+#else
+#define HDLC_MAX_MRU 1600 /* as required for FR network */
+#endif
 
 
 #ifdef __KERNEL__
 
 #include <linux/skbuff.h>
 #include <linux/netdevice.h>
-#include <net/syncppp.h>
 #include <linux/hdlc/ioctl.h>
 
 
-typedef struct {		/* Used in Cisco and PPP mode */
-	u8 address;
-	u8 control;
-	u16 protocol;
-}__attribute__ ((packed)) hdlc_header;
-
-
-
-typedef struct {
-	u32 type;		/* code */
-	u32 par1;
-	u32 par2;
-	u16 rel;		/* reliability */
-	u32 time;
-}__attribute__ ((packed)) cisco_packet;
-#define	CISCO_PACKET_LEN	18
-#define	CISCO_BIG_PACKET_LEN	20
-
-
-
-typedef struct pvc_device_struct {
-	struct net_device *master;
-	struct net_device *main;
-	struct net_device *ether; /* bridged Ethernet interface */
-	struct pvc_device_struct *next;	/* Sorted in ascending DLCI order */
-	int dlci;
-	int open_count;
-
-	struct {
-		unsigned int new: 1;
-		unsigned int active: 1;
-		unsigned int exist: 1;
-		unsigned int deleted: 1;
-		unsigned int fecn: 1;
-		unsigned int becn: 1;
-		unsigned int bandwidth;	/* Cisco LMI reporting only */
-	}state;
-}pvc_device;
-
-
-
-typedef struct hdlc_device_struct {
-	/* To be initialized by hardware driver */
+/* Used by all network devices here, pointed to by netdev_priv(dev) */
+struct hdlc_device_desc {
+	int (*netif_rx)(struct sk_buff *skb);
 	struct net_device_stats stats;
-
+};
+
+/* This structure is a private property of HDLC protocols.
+   Hardware drivers have no interest here */
+
+struct hdlc_proto {
+	int (*open)(struct net_device *dev);
+	void (*close)(struct net_device *dev);
+	void (*start)(struct net_device *dev); /* if open & DCD */
+	void (*stop)(struct net_device *dev); /* if open & !DCD */
+	void (*detach)(struct net_device *dev);
+	int (*ioctl)(struct net_device *dev, struct ifreq *ifr);
+	unsigned short (*type_trans)(struct sk_buff *skb,
+				     struct net_device *dev);
+	struct module *module;
+	struct hdlc_proto *next; /* next protocol in the list */
+};
+
+
+typedef struct hdlc_device {
 	/* used by HDLC layer to take control over HDLC device from hw driver*/
 	int (*attach)(struct net_device *dev,
 		      unsigned short encoding, unsigned short parity);
@@ -107,82 +58,18 @@ typedef struct hdlc_device_struct {
 	/* hardware driver must handle this instead of dev->hard_start_xmit */
 	int (*xmit)(struct sk_buff *skb, struct net_device *dev);
 
-
 	/* Things below are for HDLC layer internal use only */
-	struct {
-		int (*open)(struct net_device *dev);
-		void (*close)(struct net_device *dev);
-
-		/* if open & DCD */
-		void (*start)(struct net_device *dev);
-		/* if open & !DCD */
-		void (*stop)(struct net_device *dev);
-
-		void (*detach)(struct hdlc_device_struct *hdlc);
-		int (*netif_rx)(struct sk_buff *skb);
-		unsigned short (*type_trans)(struct sk_buff *skb,
-					     struct net_device *dev);
-		int id;		/* IF_PROTO_HDLC/CISCO/FR/etc. */
-	}proto;
-
+	const struct hdlc_proto *proto;
 	int carrier;
 	int open;
 	spinlock_t state_lock;
-
-	union {
-		struct {
-			fr_proto settings;
-			pvc_device *first_pvc;
-			int dce_pvc_count;
-
-			struct timer_list timer;
-			unsigned long last_poll;
-			int reliable;
-			int dce_changed;
-			int request;
-			int fullrep_sent;
-			u32 last_errors; /* last errors bit list */
-			u8 n391cnt;
-			u8 txseq; /* TX sequence number */
-			u8 rxseq; /* RX sequence number */
-		}fr;
-
-		struct {
-			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 */
-		}cisco;
-
-		struct {
-			raw_hdlc_proto settings;
-		}raw_hdlc;
-
-		struct {
-			struct ppp_device pppdev;
-			struct ppp_device *syncppp_ptr;
-			int (*old_change_mtu)(struct net_device *dev,
-					      int new_mtu);
-		}ppp;
-	}state;
+	void *state;
 	void *priv;
 }hdlc_device;
 
 
 
-int hdlc_raw_ioctl(struct net_device *dev, struct ifreq *ifr);
-int hdlc_raw_eth_ioctl(struct net_device *dev, struct ifreq *ifr);
-int hdlc_cisco_ioctl(struct net_device *dev, struct ifreq *ifr);
-int hdlc_ppp_ioctl(struct net_device *dev, struct ifreq *ifr);
-int hdlc_fr_ioctl(struct net_device *dev, struct ifreq *ifr);
-int hdlc_x25_ioctl(struct net_device *dev, struct ifreq *ifr);
-
-
-/* Exported from hdlc.o */
+/* Exported from hdlc module */
 
 /* Called by hardware driver when a user requests HDLC service */
 int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
@@ -191,17 +78,21 @@ int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
 #define register_hdlc_device(dev)	register_netdev(dev)
 void unregister_hdlc_device(struct net_device *dev);
 
+
+void register_hdlc_protocol(struct hdlc_proto *proto);
+void unregister_hdlc_protocol(struct hdlc_proto *proto);
+
 struct net_device *alloc_hdlcdev(void *priv);
 
-static __inline__ hdlc_device* dev_to_hdlc(struct net_device *dev)
+
+static __inline__ struct hdlc_device_desc* dev_to_desc(struct net_device *dev)
 {
 	return netdev_priv(dev);
 }
 
-
-static __inline__ pvc_device* dev_to_pvc(struct net_device *dev)
+static __inline__ hdlc_device* dev_to_hdlc(struct net_device *dev)
 {
-	return (pvc_device*)dev->priv;
+	return netdev_priv(dev) + sizeof(struct hdlc_device_desc);
 }
 
 
@@ -225,18 +116,14 @@ int hdlc_open(struct net_device *dev);
 /* Must be called by hardware driver when HDLC device is being closed */
 void hdlc_close(struct net_device *dev);
 
+int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
+			 int (*rx)(struct sk_buff *skb), size_t size);
 /* May be used by hardware driver to gain control over HDLC device */
-static __inline__ void hdlc_proto_detach(hdlc_device *hdlc)
-{
-	if (hdlc->proto.detach)
-		hdlc->proto.detach(hdlc);
-	hdlc->proto.detach = NULL;
-}
-
+void detach_hdlc_protocol(struct net_device *dev);
 
 static __inline__ struct net_device_stats *hdlc_stats(struct net_device *dev)
 {
-	return &dev_to_hdlc(dev)->stats;
+	return &dev_to_desc(dev)->stats;
 }
 
 
@@ -248,8 +135,8 @@ static __inline__ __be16 hdlc_type_trans(struct sk_buff *skb,
 	skb->mac.raw  = skb->data;
 	skb->dev      = dev;
 
-	if (hdlc->proto.type_trans)
-		return hdlc->proto.type_trans(skb, dev);
+	if (hdlc->proto->type_trans)
+		return hdlc->proto->type_trans(skb, dev);
 	else
 		return htons(ETH_P_HDLC);
 }
diff --git a/include/linux/hdlc/ioctl.h b/include/linux/hdlc/ioctl.h
index 78430ba3ea69..583972364357 100644
--- a/include/linux/hdlc/ioctl.h
+++ b/include/linux/hdlc/ioctl.h
@@ -1,6 +1,39 @@
 #ifndef __HDLC_IOCTL_H__
 #define __HDLC_IOCTL_H__
 
+
+#define GENERIC_HDLC_VERSION 4	/* For synchronization with sethdlc utility */
+
+#define CLOCK_DEFAULT   0	/* Default setting */
+#define CLOCK_EXT	1	/* External TX and RX clock - DTE */
+#define CLOCK_INT	2	/* Internal TX and RX clock - DCE */
+#define CLOCK_TXINT	3	/* Internal TX and external RX clock */
+#define CLOCK_TXFROMRX	4	/* TX clock derived from external RX clock */
+
+
+#define ENCODING_DEFAULT	0 /* Default setting */
+#define ENCODING_NRZ		1
+#define ENCODING_NRZI		2
+#define ENCODING_FM_MARK	3
+#define ENCODING_FM_SPACE	4
+#define ENCODING_MANCHESTER	5
+
+
+#define PARITY_DEFAULT		0 /* Default setting */
+#define PARITY_NONE		1 /* No parity */
+#define PARITY_CRC16_PR0	2 /* CRC16, initial value 0x0000 */
+#define PARITY_CRC16_PR1	3 /* CRC16, initial value 0xFFFF */
+#define PARITY_CRC16_PR0_CCITT	4 /* CRC16, initial 0x0000, ITU-T version */
+#define PARITY_CRC16_PR1_CCITT	5 /* CRC16, initial 0xFFFF, ITU-T version */
+#define PARITY_CRC32_PR0_CCITT	6 /* CRC32, initial value 0x00000000 */
+#define PARITY_CRC32_PR1_CCITT	7 /* CRC32, initial value 0xFFFFFFFF */
+
+#define LMI_DEFAULT		0 /* Default setting */
+#define LMI_NONE		1 /* No LMI, all PVCs are static */
+#define LMI_ANSI		2 /* ANSI Annex D */
+#define LMI_CCITT		3 /* ITU-T Annex A */
+#define LMI_CISCO		4 /* The "original" LMI, aka Gang of Four */
+
 typedef struct { 
 	unsigned int clock_rate; /* bits per second */
 	unsigned int clock_type; /* internal, external, TX-internal etc. */