X25: Add if_x25.h and x25 to device identifiers

V2 Feedback from John Hughes.
- Add header for userspace implementations such as xot/xoe to use
- Use explicit values for interface stability
- No changes to driver patches

V1
- Use identifiers instead of magic numbers for X25 layer 3 to device interface.
- Also fixed checkpatch notes on updated code.

[ Add new user header to include/linux/Kbuild  -DaveM ]

Signed-off-by: Andrew Hendry <andrew.hendry@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 48 insertions, 16 deletions

diff --git a/include/linux/Kbuild b/include/linux/Kbuild
index e2ea0b2159cd..2fc8e14cc24a 100644
--- a/include/linux/Kbuild
+++ b/include/linux/Kbuild
@@ -94,6 +94,7 @@ header-y += if_ppp.h
 header-y += if_slip.h
 header-y += if_strip.h
 header-y += if_tun.h
+header-y += if_x25.h
 header-y += in_route.h
 header-y += ioctl.h
 header-y += ip6_tunnel.h
diff --git a/include/linux/if_x25.h b/include/linux/if_x25.h
new file mode 100644
index 000000000000..897765f5feb8
--- /dev/null
+++ b/include/linux/if_x25.h
@@ -0,0 +1,26 @@
+/*
+ *  Linux X.25 packet to device interface
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *  GNU General Public License for more details.
+ */
+
+#ifndef _IF_X25_H
+#define _IF_X25_H
+
+#include <linux/types.h>
+
+/* Documentation/networking/x25-iface.txt */
+#define X25_IFACE_DATA          0x00
+#define X25_IFACE_CONNECT       0x01
+#define X25_IFACE_DISCONNECT    0x02
+#define X25_IFACE_PARAMS        0x03
+
+#endif /* _IF_X25_H */
diff --git a/include/net/x25device.h b/include/net/x25device.h
index 1415bcf93980..1fa08b49f1c2 100644
--- a/include/net/x25device.h
+++ b/include/net/x25device.h
@@ -3,6 +3,7 @@
 
 #include <linux/if_ether.h>
 #include <linux/if_packet.h>
+#include <linux/if_x25.h>
 #include <linux/skbuff.h>
 
 static inline __be16 x25_type_trans(struct sk_buff *skb, struct net_device *dev)
diff --git a/net/x25/x25_dev.c b/net/x25/x25_dev.c
index b9ef682230a0..9005f6daeab5 100644
--- a/net/x25/x25_dev.c
+++ b/net/x25/x25_dev.c
@@ -24,6 +24,7 @@
 #include <net/sock.h>
 #include <linux/if_arp.h>
 #include <net/x25.h>
+#include <net/x25device.h>
 
 static int x25_receive_data(struct sk_buff *skb, struct x25_neigh *nb)
 {
@@ -115,19 +116,22 @@ int x25_lapb_receive_frame(struct sk_buff *skb, struct net_device *dev,
         }
 
         switch (skb->data[0]) {
-                case 0x00:
-                        skb_pull(skb, 1);
-                        if (x25_receive_data(skb, nb)) {
-                                x25_neigh_put(nb);
-                                goto out;
-                        }
-                        break;
-                case 0x01:
-                        x25_link_established(nb);
-                        break;
-                case 0x02:
-                        x25_link_terminated(nb);
-                        break;
+
+        case X25_IFACE_DATA:
+                skb_pull(skb, 1);
+                if (x25_receive_data(skb, nb)) {
+                        x25_neigh_put(nb);
+                        goto out;
+                }
+                break;
+
+        case X25_IFACE_CONNECT:
+                x25_link_established(nb);
+                break;
+
+        case X25_IFACE_DISCONNECT:
+                x25_link_terminated(nb);
+                break;
         }
         x25_neigh_put(nb);
 drop:
@@ -148,7 +152,7 @@ void x25_establish_link(struct x25_neigh *nb)
                                 return;
                         }
                         ptr  = skb_put(skb, 1);
-                        *ptr = 0x01;
+                        *ptr = X25_IFACE_CONNECT;
                         break;
 
 #if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE)
@@ -184,7 +188,7 @@ void x25_terminate_link(struct x25_neigh *nb)
         }
 
         ptr  = skb_put(skb, 1);
-        *ptr = 0x02;
+        *ptr = X25_IFACE_DISCONNECT;
 
         skb->protocol = htons(ETH_P_X25);
         skb->dev      = nb->dev;
@@ -200,7 +204,7 @@ void x25_send_frame(struct sk_buff *skb, struct x25_neigh *nb)
         switch (nb->dev->type) {
                 case ARPHRD_X25:
                         dptr  = skb_push(skb, 1);
-                        *dptr = 0x00;
+                        *dptr = X25_IFACE_DATA;
                         break;
 
 #if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE)