From e3fcc2a15572c30c928b6b3d7d750de67b12ad60 Mon Sep 17 00:00:00 2001
From: Harshal Sheth <hsheth2@gmail.com>
Date: Sat, 7 Nov 2015 19:20:00 -0500
Subject: [PATCH] Moved linux specific code to the syscalls_linux.go file. Also
 removed unneeded constants from the syscalls_other.go file.

---
 if.go             | 22 ++--------------------
 syscalls_linux.go | 27 +++++++++++++++++++++++++++
 syscalls_other.go | 18 +++++-------------
 waterutil/doc.go  |  6 +++---
 4 files changed, 37 insertions(+), 36 deletions(-)

diff --git a/if.go b/if.go
index 229d141..9f3a97e 100644
--- a/if.go
+++ b/if.go
@@ -15,32 +15,14 @@ type Interface struct {
 // If ifName is empty, a default name (tap0, tap1, ... ) will be assigned.
 // ifName should not exceed 16 bytes.
 func NewTAP(ifName string) (ifce *Interface, err error) {
-	file, err := os.OpenFile("/dev/net/tun", os.O_RDWR, 0)
-	if err != nil {
-		return nil, err
-	}
-	name, err := createInterface(file.Fd(), ifName, cIFF_TAP|cIFF_NO_PI)
-	if err != nil {
-		return nil, err
-	}
-	ifce = &Interface{isTAP: true, file: file, name: name}
-	return
+	return newTAP(ifName)
 }
 
 // Create a new TUN interface whose name is ifName.
 // If ifName is empty, a default name (tap0, tap1, ... ) will be assigned.
 // ifName should not exceed 16 bytes.
 func NewTUN(ifName string) (ifce *Interface, err error) {
-	file, err := os.OpenFile("/dev/net/tun", os.O_RDWR, 0)
-	if err != nil {
-		return nil, err
-	}
-	name, err := createInterface(file.Fd(), ifName, cIFF_TUN|cIFF_NO_PI)
-	if err != nil {
-		return nil, err
-	}
-	ifce = &Interface{isTAP: false, file: file, name: name}
-	return
+	return newTUN(ifName)
 }
 
 // Returns true if ifce is a TUN interface, otherwise returns false;
diff --git a/syscalls_linux.go b/syscalls_linux.go
index 6bf6c57..e69c3d9 100644
--- a/syscalls_linux.go
+++ b/syscalls_linux.go
@@ -3,6 +3,7 @@
 package water
 
 import (
+	"os"
 	"strings"
 	"syscall"
 	"unsafe"
@@ -20,6 +21,32 @@ type ifReq struct {
 	pad   [0x28 - 0x10 - 2]byte
 }
 
+func newTAP(ifName string) (ifce *Interface, err error) {
+	file, err := os.OpenFile("/dev/net/tun", os.O_RDWR, 0)
+	if err != nil {
+		return nil, err
+	}
+	name, err := createInterface(file.Fd(), ifName, cIFF_TAP|cIFF_NO_PI)
+	if err != nil {
+		return nil, err
+	}
+	ifce = &Interface{isTAP: true, file: file, name: name}
+	return
+}
+
+func newTUN(ifName string) (ifce *Interface, err error) {
+	file, err := os.OpenFile("/dev/net/tun", os.O_RDWR, 0)
+	if err != nil {
+		return nil, err
+	}
+	name, err := createInterface(file.Fd(), ifName, cIFF_TUN|cIFF_NO_PI)
+	if err != nil {
+		return nil, err
+	}
+	ifce = &Interface{isTAP: false, file: file, name: name}
+	return
+}
+
 func createInterface(fd uintptr, ifName string, flags uint16) (createdIFName string, err error) {
 	var req ifReq
 	req.Flags = flags
diff --git a/syscalls_other.go b/syscalls_other.go
index d291ead..a38ce85 100644
--- a/syscalls_other.go
+++ b/syscalls_other.go
@@ -2,18 +2,10 @@
 
 package water
 
-const (
-	cIFF_TUN   = 0
-	cIFF_TAP   = 0
-	cIFF_NO_PI = 0
-)
-
-type ifReq struct {
-	Name  [0]byte
-	Flags uint16
-	pad   [0]byte
+func newTAP(ifName string) (ifce *Interface, err error) {
+	panic("water: tap interface not implemented on this platform")
 }
 
-func createInterface(fd uintptr, ifName string, flags uint16) (createdIFName string, err error) {
-	panic("water: createInterface not implemented on this platform")
-}
\ No newline at end of file
+func newTUN(ifName string) (ifce *Interface, err error) {
+	panic("water: tap interface not implemented on this platform")
+}
diff --git a/waterutil/doc.go b/waterutil/doc.go
index 14574a0..1a7cea1 100644
--- a/waterutil/doc.go
+++ b/waterutil/doc.go
@@ -8,10 +8,10 @@ TAP - MAC Frame:
   +-----------------------------------------------------------------------------
   | Octet |00|01|02|03|04|05|06|07|08|09|10|11|12|13|14|15|16|17|18|19|20|21|...
   +-----------------------------------------------------------------------------
-  | Field | MAC Destination |   MAC  Source   |EType| Payload        
+  | Field | MAC Destination |   MAC  Source   |EType| Payload
   +-----------------------------------------------------------------------------
 
-   Single-Tagged -- Octets [12,13] == {0x81, 0x00} 
+   Single-Tagged -- Octets [12,13] == {0x81, 0x00}
   +-----------------------------------------------------------------------------
   | Octet |00|01|02|03|04|05|06|07|08|09|10|11|12|13|14|15|16|17|18|19|20|21|...
   +-----------------------------------------------------------------------------
@@ -22,7 +22,7 @@ TAP - MAC Frame:
   +-----------------------------------------------------------------------------
   | Octet |00|01|02|03|04|05|06|07|08|09|10|11|12|13|14|15|16|17|18|19|20|21|...
   +-----------------------------------------------------------------------------
-  | Field | MAC Destination |   MAC  Source   | Outer Tag | Inner Tag | Payload        
+  | Field | MAC Destination |   MAC  Source   | Outer Tag | Inner Tag | Payload
   +-----------------------------------------------------------------------------
 
 TUN - IPv4 Packet: