Index: head/sys/dev/hyperv/netvsc/hv_net_vsc.h
===================================================================
--- head/sys/dev/hyperv/netvsc/hv_net_vsc.h
+++ head/sys/dev/hyperv/netvsc/hv_net_vsc.h
@@ -1256,7 +1256,7 @@
     void *additional_info, struct hn_rx_ring *rxr);
 int hv_nv_on_device_remove(struct hn_softc *sc,
     boolean_t destroy_channel);
-int hv_nv_on_send(struct vmbus_channel *chan, bool is_data_pkt,
+int hv_nv_on_send(struct vmbus_channel *chan, uint32_t rndis_mtype,
 	struct hn_send_ctx *sndc, struct vmbus_gpa *gpa, int gpa_cnt);
 int hv_nv_get_next_send_section(netvsc_dev *net_dev);
 void hv_nv_subchan_attach(struct vmbus_channel *chan,
Index: head/sys/dev/hyperv/netvsc/hv_net_vsc.c
===================================================================
--- head/sys/dev/hyperv/netvsc/hv_net_vsc.c
+++ head/sys/dev/hyperv/netvsc/hv_net_vsc.c
@@ -118,7 +118,7 @@
 	unsigned long bitsmap_words = net_dev->bitsmap_words;
 	unsigned long *bitsmap = net_dev->send_section_bitsmap;
 	unsigned long idx;
-	int ret = NVSP_1_CHIMNEY_SEND_INVALID_SECTION_INDEX;
+	int ret = HN_NVS_CHIM_IDX_INVALID;
 	int i;
 
 	for (i = 0; i < bitsmap_words; i++) {
@@ -814,32 +814,23 @@
  * Returns 0 on success, non-zero on failure.
  */
 int
-hv_nv_on_send(struct vmbus_channel *chan, bool is_data_pkt,
+hv_nv_on_send(struct vmbus_channel *chan, uint32_t rndis_mtype,
     struct hn_send_ctx *sndc, struct vmbus_gpa *gpa, int gpa_cnt)
 {
-	nvsp_msg send_msg;
+	struct hn_nvs_rndis rndis;
 	int ret;
 
-	send_msg.hdr.msg_type = nvsp_msg_1_type_send_rndis_pkt;
-	if (is_data_pkt) {
-		/* 0 is RMC_DATA */
-		send_msg.msgs.vers_1_msgs.send_rndis_pkt.chan_type = 0;
-	} else {
-		/* 1 is RMC_CONTROL */
-		send_msg.msgs.vers_1_msgs.send_rndis_pkt.chan_type = 1;
-	}
-
-	send_msg.msgs.vers_1_msgs.send_rndis_pkt.send_buf_section_idx =
-	    sndc->hn_chim_idx;
-	send_msg.msgs.vers_1_msgs.send_rndis_pkt.send_buf_section_size =
-	    sndc->hn_chim_sz;
+	rndis.nvs_type = HN_NVS_TYPE_RNDIS;
+	rndis.nvs_rndis_mtype = rndis_mtype;
+	rndis.nvs_chim_idx = sndc->hn_chim_idx;
+	rndis.nvs_chim_sz = sndc->hn_chim_sz;
 
 	if (gpa_cnt) {
 		ret = hn_nvs_send_sglist(chan, gpa, gpa_cnt,
-		    &send_msg, sizeof(nvsp_msg), sndc);
+		    &rndis, sizeof(rndis), sndc);
 	} else {
 		ret = hn_nvs_send(chan, VMBUS_CHANPKT_FLAG_RC,
-		    &send_msg, sizeof(nvsp_msg), sndc);
+		    &rndis, sizeof(rndis), sndc);
 	}
 
 	return (ret);
Index: head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c
===================================================================
--- head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c
+++ head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c
@@ -798,7 +798,7 @@
 	struct hn_txdesc *txd = sndc->hn_cbarg;
 	struct hn_tx_ring *txr;
 
-	if (sndc->hn_chim_idx != NVSP_1_CHIMNEY_SEND_INVALID_SECTION_INDEX)
+	if (sndc->hn_chim_idx != HN_NVS_CHIM_IDX_INVALID)
 		hn_chim_free(net_dev, sndc->hn_chim_idx);
 
 	txr = txd->txr;
@@ -988,8 +988,7 @@
 		txr->hn_tx_chimney_tried++;
 		send_buf_section_idx =
 		    hv_nv_get_next_send_section(net_dev);
-		if (send_buf_section_idx !=
-		    NVSP_1_CHIMNEY_SEND_INVALID_SECTION_INDEX) {
+		if (send_buf_section_idx != HN_NVS_CHIM_IDX_INVALID) {
 			uint8_t *dest = ((uint8_t *)net_dev->send_buf +
 			    (send_buf_section_idx *
 			     net_dev->send_section_size));
@@ -1045,7 +1044,7 @@
 		gpa->gpa_len = segs[i].ds_len;
 	}
 
-	send_buf_section_idx = NVSP_1_CHIMNEY_SEND_INVALID_SECTION_INDEX;
+	send_buf_section_idx = HN_NVS_CHIM_IDX_INVALID;
 	send_buf_section_size = 0;
 done:
 	txd->m = m_head;
@@ -1072,8 +1071,8 @@
 	 * Make sure that txd is not freed before ETHER_BPF_MTAP.
 	 */
 	hn_txdesc_hold(txd);
-	error = hv_nv_on_send(txr->hn_chan, true, &txd->send_ctx,
-	    txr->hn_gpa, txr->hn_gpa_cnt);
+	error = hv_nv_on_send(txr->hn_chan, HN_NVS_RNDIS_MTYPE_DATA,
+	    &txd->send_ctx, txr->hn_gpa, txr->hn_gpa_cnt);
 	if (!error) {
 		ETHER_BPF_MTAP(ifp, txd->m);
 		if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
Index: head/sys/dev/hyperv/netvsc/hv_rndis_filter.c
===================================================================
--- head/sys/dev/hyperv/netvsc/hv_rndis_filter.c
+++ head/sys/dev/hyperv/netvsc/hv_rndis_filter.c
@@ -277,8 +277,7 @@
 
 	if (tot_data_buf_len < net_dev->send_section_size) {
 		send_buf_section_idx = hv_nv_get_next_send_section(net_dev);
-		if (send_buf_section_idx !=
-			NVSP_1_CHIMNEY_SEND_INVALID_SECTION_INDEX) {
+		if (send_buf_section_idx != HN_NVS_CHIM_IDX_INVALID) {
 			char *dest = ((char *)net_dev->send_buf +
 				send_buf_section_idx * net_dev->send_section_size);
 
@@ -289,14 +288,14 @@
 		}
 		/* Failed to allocate chimney send buffer; move on */
 	}
-	send_buf_section_idx = NVSP_1_CHIMNEY_SEND_INVALID_SECTION_INDEX;
+	send_buf_section_idx = HN_NVS_CHIM_IDX_INVALID;
 	send_buf_section_size = 0;
 
 sendit:
 	hn_send_ctx_init(&request->send_ctx, cb, request,
 	    send_buf_section_idx, send_buf_section_size);
-	return hv_nv_on_send(device->net_dev->sc->hn_prichan, false,
-	    &request->send_ctx, gpa, gpa_cnt);
+	return hv_nv_on_send(device->net_dev->sc->hn_prichan,
+	    HN_NVS_RNDIS_MTYPE_CTRL, &request->send_ctx, gpa, gpa_cnt);
 }
 
 /*
@@ -1276,7 +1275,7 @@
     struct vmbus_channel *chan __unused, const struct nvsp_msg_ *msg __unused,
     int dlen __unused)
 {
-	if (sndc->hn_chim_idx != NVSP_1_CHIMNEY_SEND_INVALID_SECTION_INDEX)
+	if (sndc->hn_chim_idx != HN_NVS_CHIM_IDX_INVALID)
 		hn_chim_free(net_dev, sndc->hn_chim_idx);
 }
 
@@ -1287,7 +1286,7 @@
 {
 	rndis_request *request = sndc->hn_cbarg;
 
-	if (sndc->hn_chim_idx != NVSP_1_CHIMNEY_SEND_INVALID_SECTION_INDEX)
+	if (sndc->hn_chim_idx != HN_NVS_CHIM_IDX_INVALID)
 		hn_chim_free(net_dev, sndc->hn_chim_idx);
 
 	/*
Index: head/sys/dev/hyperv/netvsc/if_hnreg.h
===================================================================
--- head/sys/dev/hyperv/netvsc/if_hnreg.h
+++ head/sys/dev/hyperv/netvsc/if_hnreg.h
@@ -35,8 +35,19 @@
 #define HN_NVS_RXBUF_SIG		0xcafe
 #define HN_NVS_CHIM_SIG			0xface
 
+#define HN_NVS_CHIM_IDX_INVALID		0xffffffff
+
+#define HN_NVS_RNDIS_MTYPE_DATA		0
+#define HN_NVS_RNDIS_MTYPE_CTRL		1
+
+/*
+ * NVS message transacion status codes.
+ */
 #define HN_NVS_STATUS_OK		1
 
+/*
+ * NVS request/response message types.
+ */
 #define HN_NVS_TYPE_INIT		1
 #define HN_NVS_TYPE_INIT_RESP		2
 #define HN_NVS_TYPE_NDIS_INIT		100
@@ -46,6 +57,7 @@
 #define HN_NVS_TYPE_CHIM_CONN		104
 #define HN_NVS_TYPE_CHIM_CONNRESP	105
 #define HN_NVS_TYPE_CHIM_DISCONN	106
+#define HN_NVS_TYPE_RNDIS		107
 #define HN_NVS_TYPE_NDIS_CONF		125
 #define HN_NVS_TYPE_SUBCH_REQ		133
 #define HN_NVS_TYPE_SUBCH_RESP		133	/* same as SUBCH_REQ */
@@ -162,4 +174,21 @@
 	uint32_t	nvs_nsubch;
 } __packed;
 
+struct hn_nvs_rndis {
+	uint32_t	nvs_type;	/* HN_NVS_TYPE_RNDIS */
+	uint32_t	nvs_rndis_mtype;/* HN_NVS_RNDIS_MTYPE_ */
+	/*
+	 * Chimney sending buffer index and size.
+	 *
+	 * NOTE:
+	 * If nvs_chim_idx is set to HN_NVS_CHIM_IDX_INVALID
+	 * and nvs_chim_sz is set to 0, then chimney sending
+	 * buffer is _not_ used by this RNDIS message.
+	 */
+	uint32_t	nvs_chim_idx;
+	uint32_t	nvs_chim_sz;
+	uint8_t		nvs_rsvd[16];
+} __packed;
+CTASSERT(sizeof(struct hn_nvs_rndis) >= HN_NVS_REQSIZE_MIN);
+
 #endif	/* !_IF_HNREG_H_ */
Index: head/sys/dev/hyperv/netvsc/if_hnvar.h
===================================================================
--- head/sys/dev/hyperv/netvsc/if_hnvar.h
+++ head/sys/dev/hyperv/netvsc/if_hnvar.h
@@ -32,7 +32,7 @@
 #include <sys/param.h>
 
 #include <dev/hyperv/include/vmbus.h>
-#include <dev/hyperv/netvsc/hv_net_vsc.h>
+#include <dev/hyperv/netvsc/if_hnreg.h>
 
 struct netvsc_dev_;
 struct nvsp_msg_;
@@ -51,12 +51,12 @@
 	int			hn_chim_sz;
 };
 
-#define HN_SEND_CTX_INITIALIZER(cb, cbarg)				\
-{									\
-	.hn_cb		= cb,						\
-	.hn_cbarg	= cbarg,					\
-	.hn_chim_idx	= NVSP_1_CHIMNEY_SEND_INVALID_SECTION_INDEX,	\
-	.hn_chim_sz	= 0						\
+#define HN_SEND_CTX_INITIALIZER(cb, cbarg)		\
+{							\
+	.hn_cb		= cb,				\
+	.hn_cbarg	= cbarg,			\
+	.hn_chim_idx	= HN_NVS_CHIM_IDX_INVALID,	\
+	.hn_chim_sz	= 0				\
 }
 
 static __inline void
@@ -75,8 +75,7 @@
     void *cbarg)
 {
 
-	hn_send_ctx_init(sndc, cb, cbarg,
-	    NVSP_1_CHIMNEY_SEND_INVALID_SECTION_INDEX, 0);
+	hn_send_ctx_init(sndc, cb, cbarg, HN_NVS_CHIM_IDX_INVALID, 0);
 }
 
 static __inline int