datapath-windows: Add support for Netfilter netlink message

Introduce NF_GEN_MSG_HDR similar to GENL_MSG_HDR that will be used for
communicating via netfilter-netlink channel. This will be used by
userspace to retrieve and modify Conntrack data in Windows.

Signed-off-by: Sairam Venugopal <vsairam@vmware.com>
Acked-by: Paul-Daniel Boca <pboca@cloudbasesolutions.com>
Acked-by: Nithin Raju <nithin@vmware.com>
Signed-off-by: Gurucharan Shetty <guru@ovn.org>

3 files changed, 27 insertions, 2 deletions

diff --git a/datapath-windows/ovsext/Netlink/Netlink.c b/datapath-windows/ovsext/Netlink/Netlink.c
index 1eec320e2..ccf9ec1f0 100644
--- a/datapath-windows/ovsext/Netlink/Netlink.c
+++ b/datapath-windows/ovsext/Netlink/Netlink.c
@@ -672,6 +672,17 @@ NlMsgAttrsLen(const PNL_MSG_HDR nlh)
     return NlHdrPayloadLen(nlh) - GENL_HDRLEN - OVS_HDRLEN;
 }
 
+/*
+ * ---------------------------------------------------------------------------
+ * Returns size of to nfnlmsg attributes.
+ * ---------------------------------------------------------------------------
+ */
+UINT32
+NlNfMsgAttrsLen(const PNL_MSG_HDR nlh)
+{
+    return NlHdrPayloadLen(nlh) - NF_GEN_MSG_HDRLEN - OVS_HDRLEN;
+}
+
 /* Netlink message parse. */
 
 /*
diff --git a/datapath-windows/ovsext/Netlink/Netlink.h b/datapath-windows/ovsext/Netlink/Netlink.h
index b1b3bed51..5261b9ece 100644
--- a/datapath-windows/ovsext/Netlink/Netlink.h
+++ b/datapath-windows/ovsext/Netlink/Netlink.h
@@ -27,10 +27,14 @@
  */
 typedef struct _OVS_MESSAGE {
     NL_MSG_HDR nlMsg;
-    GENL_MSG_HDR genlMsg;
+    union {
+        GENL_MSG_HDR genlMsg;
+        NF_GEN_MSG_HDR nfGenMsg;
+    };
     OVS_HDR ovsHdr;
     /* Variable length nl_attrs follow. */
 } OVS_MESSAGE, *POVS_MESSAGE;
+BUILD_ASSERT_DECL(sizeof(GENL_MSG_HDR) == sizeof(NF_GEN_MSG_HDR));
 
 /*
  * Structure of an error message sent as a reply from kernel.
@@ -107,6 +111,7 @@ PCHAR NlHdrPayload(const PNL_MSG_HDR nlh);
 UINT32 NlHdrPayloadLen(const PNL_MSG_HDR nlh);
 PNL_ATTR NlMsgAttrs(const PNL_MSG_HDR nlh);
 UINT32 NlMsgAttrsLen(const PNL_MSG_HDR nlh);
+UINT32 NlNfMsgAttrsLen(const PNL_MSG_HDR nlh);
 
 /* Netlink message parse */
 PNL_MSG_HDR NlMsgNext(const PNL_MSG_HDR nlh);
@@ -135,7 +140,7 @@ const PNL_ATTR NlAttrFindNested(const PNL_ATTR nla,
                                 UINT16 type);
 BOOLEAN NlAttrParse(const PNL_MSG_HDR nlMsg, UINT32 attrOffset,
                     UINT32 totalAttrLen, const NL_POLICY policy[],
-                    const UINT32 numPolicy, PNL_ATTR attrs[], 
+                    const UINT32 numPolicy, PNL_ATTR attrs[],
                     UINT32 numAttrs);
 BOOLEAN NlAttrParseNested(const PNL_MSG_HDR nlMsg, UINT32 attrOffset,
                           UINT32 totalAttrLen, const NL_POLICY policy[],
diff --git a/datapath-windows/ovsext/Netlink/NetlinkProto.h b/datapath-windows/ovsext/Netlink/NetlinkProto.h
index f2e9aee47..beb14d552 100644
--- a/datapath-windows/ovsext/Netlink/NetlinkProto.h
+++ b/datapath-windows/ovsext/Netlink/NetlinkProto.h
@@ -98,6 +98,14 @@ typedef struct _GENL_MSG_HDR {
 } GENL_MSG_HDR, *PGENL_MSG_HDR;
 BUILD_ASSERT_DECL(sizeof(GENL_MSG_HDR) == 4);
 
+/* Netfilter Generic Message */
+typedef struct _NF_GEN_MSG_HDR {
+    UINT8 nfgenFamily;   /* AF_xxx */
+    UINT8 version;       /* nfnetlink version */
+    UINT16 resId;        /* resource id */
+} NF_GEN_MSG_HDR, *PNF_GEN_MSG_HDR;
+BUILD_ASSERT_DECL(sizeof(NF_GEN_MSG_HDR) == 4);
+
 /* Netlink attributes */
 typedef struct _NL_ATTR {
     UINT16 nlaLen;
@@ -113,6 +121,7 @@ BUILD_ASSERT_DECL(sizeof(NL_ATTR) == 4);
 
 #define NLMSG_HDRLEN ((INT) NLMSG_ALIGN(sizeof(NL_MSG_HDR)))
 #define GENL_HDRLEN NLMSG_ALIGN(sizeof(GENL_MSG_HDR))
+#define NF_GEN_MSG_HDRLEN NLMSG_ALIGN(sizeof(NF_GEN_MSG_HDR))
 #define OVS_HDRLEN NLMSG_ALIGN(sizeof(OVS_HDR))
 #define NLA_HDRLEN ((INT) NLA_ALIGN(sizeof(NL_ATTR)))