openflow/learn_flow_spec: Fix to use src field if dst field is omitted, as dst field.

examples/nx_learning_switch/lib/nx_learning_switch.ex

@@ -56,29 +56,7 @@ defmodule NxLearningSwitch do
     send_flow_mod_add(
       datapath_id,
       table_id: 0,
-      instructions: ApplyActions.new([
+      instructions: l2_learning_instr()
-        NxLearn.new(
-          table_id: 1,
-          priority: 2,
-          hard_timeout: 10,
-          flow_specs: [
-            NxFlowSpecMatch.new(
-              src: :eth_src,
-              dst: :eth_dst
-            ),
-            NxFlowSpecMatch.new(
-              src: :vlan_vid,
-              dst: :vlan_vid,
-              offset: 0,
-              n_bits: 12
-            ),
-            NxFlowSpecOutput.new(
-              src: :nx_in_port
-            )
-          ]
-        ),
-        NxResubmitTable.new(1)
-      ])
     )
   end
 
@@ -90,4 +68,28 @@ defmodule NxLearningSwitch do
       instructions: ApplyActions.new(Output.new(:flood))
     )
   end
+
+  defp l2_learning_instr do
+    ApplyActions.new([
+      l2_learning_action(),
+      NxResubmitTable.new(1)
+    ])
+  end
+
+  defp l2_learning_action do
+    NxLearn.new(
+      table_id: 1,
+      priority: 2,
+      hard_timeout: 10,
+      flow_specs: l2_learning_flow_specs()
+    )
+  end
+
+  defp l2_learning_flow_specs do
+    [
+      NxFlowSpecMatch.new(src: :eth_src, dst: :eth_dst),
+      NxFlowSpecMatch.new(src: :vlan_vid, n_bits: 12),
+      NxFlowSpecOutput.new(src: :nx_in_port)
+    ]
+  end
 end

lib/openflow/actions/nx_flow_spec_match.ex

@@ -29,8 +29,8 @@ defmodule Openflow.Action.NxFlowSpecMatch do
           dst_offset: non_neg_integer()
         ) :: t()
   def new(options \\ []) do
-    dst = options[:dst] || raise ":dst must be specified"
     src = options[:src] || raise ":src must be specified"
+    dst = options[:dst] || src
     n_bits = options[:n_bits] || Openflow.Match.n_bits_of(dst)
 
     %NxFlowSpecMatch{

test/lib/openflow/ofp_action_test.exs

@@ -741,7 +741,7 @@ defmodule OfpActionTest do
           fin_idle_timeout: 2,
           fin_hard_timeout: 4,
           flow_specs: [
-            Openflow.Action.NxFlowSpecMatch.new(src: :nx_vlan_tci, dst: :nx_vlan_tci, n_bits: 12),
+            Openflow.Action.NxFlowSpecMatch.new(src: :nx_vlan_tci, n_bits: 12),
             Openflow.Action.NxFlowSpecMatch.new(src: :nx_eth_src, dst: :nx_eth_dst),
             Openflow.Action.NxFlowSpecOutput.new(src: :nx_in_port)
           ]
@@ -773,7 +773,7 @@ defmodule OfpActionTest do
           result_dst: :reg0,
           result_dst_offset: 8,
           flow_specs: [
-            Openflow.Action.NxFlowSpecMatch.new(src: :nx_vlan_tci, dst: :nx_vlan_tci, n_bits: 12),
+            Openflow.Action.NxFlowSpecMatch.new(src: :nx_vlan_tci, n_bits: 12),
             Openflow.Action.NxFlowSpecMatch.new(src: :nx_eth_src, dst: :nx_eth_dst),
             Openflow.Action.NxFlowSpecOutput.new(src: :nx_in_port)
           ]
@@ -846,22 +846,21 @@ defmodule OfpActionTest do
     end
 
     test "with no option" do
-      assert_raise RuntimeError, ":dst must be specified", fn ->
+      assert_raise RuntimeError, ":src must be specified", fn ->
         Openflow.Action.NxFlowSpecMatch.new()
       end
     end
 
-    test "with no dst option" do
-      assert_raise RuntimeError, ":dst must be specified", fn ->
-        Openflow.Action.NxFlowSpecMatch.new(src: :in_port)
-      end
-    end
-
     test "with no src option" do
       assert_raise RuntimeError, ":src must be specified", fn ->
         Openflow.Action.NxFlowSpecMatch.new(dst: :reg0)
       end
     end
+
+    test "with no dst option" do
+      learn = Openflow.Action.NxFlowSpecMatch.new(src: :in_port)
+      assert learn.dst == :in_port
+    end
   end
 
   describe "Openflow.Action.NxFlowSpecLoad" do