netlink: Add ip rule support

lib/linux/netlink/route.rb

@@ -13,6 +13,7 @@ module Netlink
     autoload :VlanHandler, 'linux/netlink/route/vlan_handler'
     autoload :AddrHandler, 'linux/netlink/route/addr_handler'
     autoload :RouteHandler, 'linux/netlink/route/route_handler'
+    autoload :RuleHandler, 'linux/netlink/route/rule_handler'
 
     # This class formats and receives messages using NETLINK_ROUTE protocol
     class Socket < NLSocket
@@ -40,6 +41,10 @@ module Netlink
         @route ||= RouteHandler.new(self)
       end
 
+      def rule
+        @rule ||= RuleHandler.new(self)
+      end
+
       # Convert an interface index into name string, or nil if the
       # index is nil or 0. Raises exception for unknown values.
       #
@@ -69,3 +74,4 @@ module Netlink
   end
 end
 end # module Linux
+

lib/linux/netlink/route/route_handler.rb

@@ -8,7 +8,8 @@ module Netlink
 
   # struct rtmsg
   class RT < RtattrMessage
-    code RTM_NEWROUTE, RTM_DELROUTE, RTM_GETROUTE
+    code RTM_NEWROUTE, RTM_DELROUTE, RTM_GETROUTE,
+         RTM_NEWRULE,  RTM_DELRULE,  RTM_GETRULE
 
     field :family, :uchar			# Socket::AF_*
     field :dst_len, :uchar
@@ -197,3 +198,4 @@ module Netlink
   end
 end
 end # module Linux
+

lib/linux/netlink/route/rule_handler.rb

@@ -0,0 +1,102 @@
+require 'linux/netlink/route'
+require 'linux/netlink/route/route_handler'
+
+module Linux
+module Netlink
+
+  module Route
+    # This class manipulates the kernel routing table by adding and removing
+    # rules
+    class RuleHandler < Handler
+      def clear_cache
+        @rule = nil
+      end
+
+      def read_rule(opt=nil, &blk)
+        @rtsocket.send_request RTM_GETRULE, RT.new(opt),
+                     NLM_F_ROOT | NLM_F_MATCH | NLM_F_REQUEST
+        @rtsocket.receive_until_done(RTM_NEWRULE, &blk)
+      end
+
+
+      Filter = RouteHandler::Filter
+
+      # Return the memoized rule list, filtered according to
+      # the optional criteria. Examples:
+      #    :family => Socket::AF_INET
+      #    :table => Linux::RT_TABLE_DEFAULT
+      #    :protocol => Linux::RTPROT_STATIC
+      #    :type => Linux::RTN_UNICAST
+      #    :scope => Linux::RT_SCOPE_HOST
+      #    :flags => Linux::RTM_F_NOTIFY
+      #    :noflags => Linux::RTM_F_CLONED
+      #    :oif => "eth0"
+      #    :iif => "eth1"
+      def list(filter=nil, &blk)
+        @rule ||= read_rule
+        filter[:oif] = index(filter[:oif]) if filter && filter.has_key?(:oif)
+        filter[:iif] = index(filter[:iif]) if filter && filter.has_key?(:iif)
+        filter_list(@rule, filter, &blk)
+      end
+      alias :each :list
+
+      def add(opt)
+        iproute_modify(RTM_NEWRULE, NLM_F_CREATE|NLM_F_EXCL, opt)
+      end
+
+      def delete(opt)
+        iproute_modify(RTM_DELRULE, 0, opt)
+      end
+
+      # Get route matching given criteria
+      def get(msg)
+        msg = RT.new(msg)
+        raise "Missing :dst" unless msg.dst
+        msg.iif = index(msg.iif) if msg.iif.is_a?(String)
+        msg.oif = index(msg.oif) if msg.oif.is_a?(String)
+        @rtsocket.cmd RTM_GETRULE, msg, NLM_F_REQUEST, RTM_NEWRULE
+      end
+
+      def iproute_modify(code, flags, msg) #:nodoc:
+        msg = RT.new(msg)
+
+        if code != RTM_DELRULE
+          msg.protocol ||= RTPROT_BOOT
+          msg.type ||= RTN_UNICAST
+        end
+        # There is scary code in ip/iproute.c for setting defaults
+        unless msg.table
+          msg.table = case msg.type
+          when RTN_LOCAL, RTN_BROADCAST, RTN_NAT, RTN_ANYCAST
+            RT_TABLE_LOCAL
+          else
+            RT_TABLE_MAIN
+          end
+        end
+        unless msg.scope
+          msg.scope = (code != RTM_DELRULE) ? RT_SCOPE_UNIVERSE : RT_SCOPE_NOWHERE
+          case msg.type
+          when RTN_LOCAL, RTN_NAT
+            msg.scope = RT_SCOPE_HOST
+          when RTN_BROADCAST, RTN_MULTICAST, RTN_ANYCAST
+            msg.scope RT_SCOPE_LINK
+          when RTN_UNICAST, RTN_UNSPEC
+            if code == RTM_DELRULE
+              msg.scope = RT_SCOPE_NOWHERE
+            elsif !msg.gateway && !msg.multipath
+              msg.scope = RT_SCOPE_LINK
+            end
+          end
+        end
+
+        msg.iif = index(msg.iif) if msg.iif.is_a?(String)
+        msg.oif = index(msg.oif) if msg.oif.is_a?(String)
+
+        @rtsocket.cmd code, msg, flags|NLM_F_REQUEST
+        clear_cache
+      end
+    end
+  end
+end
+end # module Linux
+