From a6eda43b2ef5fc871545b2957f03145388ed92ef Mon Sep 17 00:00:00 2001
From: Brian Candler <B.Candler@pobox.com>
Date: Mon, 2 May 2011 18:17:24 +0100
Subject: [PATCH] Another little reorg; we are quite tightly bound to
 implementation of CStruct

---
 README                                  | 25 +++++++++++++++++++++++++
 lib/{cstruct.rb => netlink/c_struct.rb} |  9 ++++++---
 lib/netlink/message.rb                  |  8 ++++----
 3 files changed, 35 insertions(+), 7 deletions(-)
 rename lib/{cstruct.rb => netlink/c_struct.rb} (97%)

diff --git a/README b/README
index b7793b2..0397761 100644
--- a/README
+++ b/README
@@ -5,6 +5,29 @@ This library provides an API for using a Linux Netlink socket, for doing
 things like manipulating IP interfaces, routes and firewall rules
 programmatically.
 
+Code organisation
+=================
+
+There are separate classes for each Netlink protocol providing a high-level
+API. These all in turn use the NLSocket class, which has methods for adding
+the headers to messages and sending them over a socket. The messages
+themselves are built using class Message or RtattrMessage, which in turn are
+subclasses of CStruct, which performs the low-level packing and unpacking of
+the message bodies.
+
+     Route  Firewall  ...etc
+       |       |       |
+       +-------+-------+
+               |
+               v
+            NLSocket
+               |
+               v
+    Message / RtattrMessage
+               |
+               v
+            CStruct
+
 Useful reference material
 =========================
 
@@ -41,6 +64,8 @@ TODO
 ====
 
 * Exception hierarchy
+* Unit tests
+* Integration tests
 
 Copyright
 =========
diff --git a/lib/cstruct.rb b/lib/netlink/c_struct.rb
similarity index 97%
rename from lib/cstruct.rb
rename to lib/netlink/c_struct.rb
index e7da8ce..0e1db8d 100644
--- a/lib/cstruct.rb
+++ b/lib/netlink/c_struct.rb
@@ -1,10 +1,12 @@
+module Netlink
+
 # This class allows defining of C-style structures, and converting
 # object instances to and from a packed binary representation.
 #
-# A new structure is created by subclassing Cstruct, and then using the
+# A new structure is created by subclassing CStruct, and then using the
 # 'field' metaprogramming macro to define each field:
 #
-#   class Foo < Cstruct
+#   class Foo < CStruct
 #     field :bar, :char
 #     field :baz, :long
 #
@@ -25,7 +27,7 @@
 #   str = msg.to_s              # convert to binary
 #   msg2 = Foo.parse(str)       # convert from binary
 #   msg2 = Foo.new(msg)         # copy an existing object
-class Cstruct
+class CStruct
   EMPTY_STRING = "".freeze #:nodoc:
   EMPTY_ARRAY  = [].freeze #:nodoc:
 
@@ -183,3 +185,4 @@ class Cstruct
     (val + (m-1)) & ~(m-1)
   end
 end
+end # module Netlink
diff --git a/lib/netlink/message.rb b/lib/netlink/message.rb
index e1bf227..be8701f 100644
--- a/lib/netlink/message.rb
+++ b/lib/netlink/message.rb
@@ -1,4 +1,4 @@
-require 'cstruct'
+require 'netlink/c_struct'
 require 'netlink/constants'
 require 'ipaddr'
 
@@ -6,8 +6,8 @@ module Netlink
   NLMSGHDR_PACK = "LSSLL".freeze  # :nodoc:
   NLMSGHDR_SIZE = [0,0,0,0,0].pack(NLMSGHDR_PACK).bytesize # :nodoc:
 
-  EMPTY_STRING = Cstruct::EMPTY_STRING #:nodoc:
-  EMPTY_ARRAY  = Cstruct::EMPTY_ARRAY  #:nodoc:
+  EMPTY_STRING = "".freeze #:nodoc:
+  EMPTY_ARRAY  = [].freeze #:nodoc:
 
   # This is the base class from which all Netlink messages are derived.
   # To define a new Netlink message, make a subclass and then call the
@@ -16,7 +16,7 @@ module Netlink
   # types are to be built using this structure.
   #
   # Use RtattrMessage instead for messages which are followed by variable rtattrs.
-  class Message < Cstruct
+  class Message < CStruct
     # Map of numeric message type code => message class
     CODE_TO_MESSAGE = {}