brcompat: Add comments to netlink header.

diff --git a/include/openflow/brcompat-netlink.h b/include/openflow/brcompat-netlink.h
index 34560a3ab4bb9200e68e065bc99e41605ca4f360..8447960be5619ba080587eb69f20d0b93e9d6d7f 100644 (file)
--- a/include/openflow/brcompat-netlink.h
+++ b/include/openflow/brcompat-netlink.h
@@ -1,4 +1,4 @@
-/* Copyright (c) 2008 The Board of Trustees of The Leland Stanford
+/* Copyright (c) 2008, 2009 The Board of Trustees of The Leland Stanford
  * Junior University
  * 
  * We are making the OpenFlow specification and associated documentation
@@ -51,12 +51,17 @@ enum {
 /* Commands that can be executed on the datapath's netlink interface. */
 enum brc_genl_command {
        BRC_GENL_C_UNSPEC,
-       BRC_GENL_C_DP_ADD,      /* Datapath created. */
-       BRC_GENL_C_DP_DEL,      /* Datapath destroyed. */
-       BRC_GENL_C_DP_RESULT,   /* Result of datapath command from vswitchd. */
-       BRC_GENL_C_PORT_ADD,    /* Port added to datapath. */
-       BRC_GENL_C_PORT_DEL,    /* Port removed from datapath. */
-       BRC_GENL_C_QUERY_MC,    /* Get multicast group for brcompat. */
+
+       /*
+        * "K:" messages are sent by the kernel to userspace.
+        * "U:" messages are sent by userspace to the kernel.
+        */
+       BRC_GENL_C_DP_ADD,      /* K: Datapath created. */
+       BRC_GENL_C_DP_DEL,      /* K: Datapath destroyed. */
+       BRC_GENL_C_DP_RESULT,   /* U: Result of datapath command from vswitchd. */
+       BRC_GENL_C_PORT_ADD,    /* K: Port added to datapath. */
+       BRC_GENL_C_PORT_DEL,    /* K: Port removed from datapath. */
+       BRC_GENL_C_QUERY_MC,    /* U: Get multicast group for brcompat. */
 
        __BRC_GENL_C_MAX,
        BRC_GENL_C_MAX = __BRC_GENL_C_MAX - 1