[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. */