[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, 41 insertions, 9 deletions

diff --git a/drivers/net/wan/hdlc_raw.c b/drivers/net/wan/hdlc_raw.c
index f15aa6ba77f1..fe3cae5c6b9d 100644
--- a/drivers/net/wan/hdlc_raw.c
+++ b/drivers/net/wan/hdlc_raw.c
@@ -2,7 +2,7 @@
  * Generic HDLC support routines for Linux
  * HDLC support
  *
- * Copyright (C) 1999 - 2003 Krzysztof Halasa <khc@pm.waw.pl>
+ * Copyright (C) 1999 - 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
@@ -24,6 +24,8 @@
 #include <linux/hdlc.h>
 
 
+static int raw_ioctl(struct net_device *dev, struct ifreq *ifr);
+
 static __be16 raw_type_trans(struct sk_buff *skb, struct net_device *dev)
 {
         return __constant_htons(ETH_P_IP);
@@ -31,7 +33,14 @@ static __be16 raw_type_trans(struct sk_buff *skb, struct net_device *dev)
 
 
 
-int hdlc_raw_ioctl(struct net_device *dev, struct ifreq *ifr)
+static struct hdlc_proto proto = {
+        .type_trans     = raw_type_trans,
+        .ioctl          = raw_ioctl,
+        .module         = THIS_MODULE,
+};
+
+
+static int raw_ioctl(struct net_device *dev, struct ifreq *ifr)
 {
         raw_hdlc_proto __user *raw_s = ifr->ifr_settings.ifs_ifsu.raw_hdlc;
         const size_t size = sizeof(raw_hdlc_proto);
@@ -41,12 +50,14 @@ int hdlc_raw_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_HDLC;
                 if (ifr->ifr_settings.size < size) {
                         ifr->ifr_settings.size = size; /* data size wanted */
                         return -ENOBUFS;
                 }
-                if (copy_to_user(raw_s, &hdlc->state.raw_hdlc.settings, size))
+                if (copy_to_user(raw_s, hdlc->state, size))
                         return -EFAULT;
                 return 0;
 
@@ -71,12 +82,11 @@ int hdlc_raw_ioctl(struct net_device *dev, struct ifreq *ifr)
                 if (result)
                         return result;
 
-                hdlc_proto_detach(hdlc);
-                memcpy(&hdlc->state.raw_hdlc.settings, &new_settings, size);
-                memset(&hdlc->proto, 0, sizeof(hdlc->proto));
-
-                hdlc->proto.type_trans = raw_type_trans;
-                hdlc->proto.id = IF_PROTO_HDLC;
+                result = attach_hdlc_protocol(dev, &proto, NULL,
+                                              sizeof(raw_hdlc_proto));
+                if (result)
+                        return result;
+                memcpy(hdlc->state, &new_settings, size);
                 dev->hard_start_xmit = hdlc->xmit;
                 dev->hard_header = NULL;
                 dev->type = ARPHRD_RAWHDLC;
@@ -88,3 +98,25 @@ int hdlc_raw_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("Raw HDLC protocol support for generic HDLC");
+MODULE_LICENSE("GPL v2");