Windows: Add support for handling protocol (netlink family)

Windows datapath currently has no notion of netlink family.
It assumes all netlink messages to belong to NETLINK_GENERIC family.
This patch adds support for handling other protocols if the userspace sends it down to kernel.

This patch introduces a new NETLINK_CMD - OVS_CTRL_CMD_SOCK_PROP to manage
all properties associated with a socket. The properties are passed down as
netlink message attributes. This makes it easier to introduce other
properties in the future.

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

1 files changed, 103 insertions, 1 deletions

diff --git a/datapath-windows/ovsext/Datapath.c b/datapath-windows/ovsext/Datapath.c
index 16d58ef6e..4f47be575 100644
--- a/datapath-windows/ovsext/Datapath.c
+++ b/datapath-windows/ovsext/Datapath.c
@@ -87,7 +87,8 @@ static NetlinkCmdHandler OvsPendEventCmdHandler,
                          OvsReadEventCmdHandler,
                          OvsNewDpCmdHandler,
                          OvsGetDpCmdHandler,
-                         OvsSetDpCmdHandler;
+                         OvsSetDpCmdHandler,
+                         OvsSockPropCmdHandler;
 
 NetlinkCmdHandler        OvsGetNetdevCmdHandler,
                          OvsGetVportCmdHandler,
@@ -147,6 +148,11 @@ NETLINK_CMD nlControlFamilyCmdOps[] = {
       .handler = OvsReadPacketCmdHandler,
       .supportedDevOp = OVS_READ_DEV_OP,
       .validateDpIndex = FALSE,
+    },
+    { .cmd = OVS_CTRL_CMD_SOCK_PROP,
+      .handler = OvsSockPropCmdHandler,
+      .supportedDevOp = OVS_TRANSACTION_DEV_OP,
+      .validateDpIndex = FALSE,
     }
 };
 
@@ -1685,3 +1691,99 @@ OvsReadEventCmdHandler(POVS_USER_PARAMS_CONTEXT usrParamsCtx,
 cleanup:
     return status;
 }
+
+/*
+ * --------------------------------------------------------------------------
+ *  Command Handler for 'OVS_CTRL_CMD_SOCK_PROP'.
+ *
+ *  Handler to set and verify socket properties between userspace and kernel.
+ *
+ *  Protocol is passed down by the userspace. It refers to the NETLINK family
+ *  and could be of different types (NETLINK_GENERIC/NETLINK_NETFILTER etc.,)
+ *  This function parses out the protocol and adds it to the open instance.
+ *
+ *  PID is generated by the kernel and is set in userspace after querying the
+ *  kernel for it. This function does not modify PID set in the kernel,
+ *  instead it verifies if it was sent down correctly.
+ *
+ *  XXX -This method can be modified to handle all Socket properties thereby
+ *  eliminating the use of OVS_IOCTL_GET_PID
+ *
+ * --------------------------------------------------------------------------
+ */
+static NTSTATUS
+OvsSockPropCmdHandler(POVS_USER_PARAMS_CONTEXT usrParamsCtx,
+                      UINT32 *replyLen)
+{
+    static const NL_POLICY ovsSocketPolicy[] = {
+        [OVS_NL_ATTR_SOCK_PROTO] = { .type = NL_A_U32, .optional = TRUE },
+        [OVS_NL_ATTR_SOCK_PID] = { .type = NL_A_U32, .optional = TRUE }
+    };
+    PNL_ATTR attrs[ARRAY_SIZE(ovsSocketPolicy)];
+
+    if (usrParamsCtx->outputLength < sizeof(OVS_MESSAGE)) {
+        return STATUS_NDIS_INVALID_LENGTH;
+    }
+
+    NL_BUFFER nlBuf;
+    POVS_MESSAGE msgIn = (POVS_MESSAGE)usrParamsCtx->inputBuffer;
+    POVS_MESSAGE msgOut = (POVS_MESSAGE)usrParamsCtx->outputBuffer;
+    POVS_OPEN_INSTANCE instance = (POVS_OPEN_INSTANCE)usrParamsCtx->ovsInstance;
+    UINT32 protocol;
+    PNL_MSG_HDR nlMsg;
+    UINT32 pid;
+
+    /* Parse the input */
+    if (!NlAttrParse((PNL_MSG_HDR)msgIn,
+                     NLMSG_HDRLEN + GENL_HDRLEN + OVS_HDRLEN,
+                     NlMsgAttrsLen((PNL_MSG_HDR)msgIn),
+                     ovsSocketPolicy,
+                     ARRAY_SIZE(ovsSocketPolicy),
+                     attrs,
+                     ARRAY_SIZE(attrs))) {
+        return STATUS_INVALID_PARAMETER;
+    }
+
+    /* Set the Protocol if it was passed down */
+    if (attrs[OVS_NL_ATTR_SOCK_PROTO]) {
+        protocol = NlAttrGetU32(attrs[OVS_NL_ATTR_SOCK_PROTO]);
+        if (protocol) {
+            instance->protocol = protocol;
+        }
+    }
+
+    /* Verify if the PID sent down matches the kernel */
+    if (attrs[OVS_NL_ATTR_SOCK_PID]) {
+        pid = NlAttrGetU32(attrs[OVS_NL_ATTR_SOCK_PID]);
+        if (pid != instance->pid) {
+            OVS_LOG_ERROR("Received invalid pid:%d expected:%d",
+                          pid, instance->pid);
+            return STATUS_INVALID_PARAMETER;
+        }
+    }
+
+    /* Prepare the output */
+    NlBufInit(&nlBuf, usrParamsCtx->outputBuffer, usrParamsCtx->outputLength);
+    if(!NlFillOvsMsg(&nlBuf, msgIn->nlMsg.nlmsgType, NLM_F_MULTI,
+                      msgIn->nlMsg.nlmsgSeq, msgIn->nlMsg.nlmsgPid,
+                      msgIn->genlMsg.cmd, msgIn->genlMsg.version,
+                      gOvsSwitchContext->dpNo)){
+        return STATUS_INVALID_BUFFER_SIZE;
+    }
+
+    if (!NlMsgPutTailU32(&nlBuf, OVS_NL_ATTR_SOCK_PID,
+                         instance->pid)) {
+        return STATUS_INVALID_BUFFER_SIZE;
+    }
+
+    if (!NlMsgPutTailU32(&nlBuf, OVS_NL_ATTR_SOCK_PROTO,
+                         instance->protocol)) {
+        return STATUS_INVALID_BUFFER_SIZE;
+    }
+
+    nlMsg = (PNL_MSG_HDR)NlBufAt(&nlBuf, 0, 0);
+    nlMsg->nlmsgLen = NlBufSize(&nlBuf);
+    *replyLen = msgOut->nlMsg.nlmsgLen;
+
+    return STATUS_SUCCESS;
+}