diff --git a/configure b/configure
index 423f435550..2b4e1af7eb 100755
--- a/configure
+++ b/configure
@@ -2249,13 +2249,21 @@ EOF
 fi
 
 ##########################################
-# netmap headers probe
+# netmap support probe
+# Apart from looking for netmap headers, we make sure that the host API version
+# supports the netmap backend (>=11). The upper bound (15) is meant to simulate
+# a minor/major version number. Minor new features will be marked with values up
+# to 15, and if something happens that requires a change to the backend we will
+# move above 15, submit the backend fixes and modify this two bounds.
 if test "$netmap" != "no" ; then
   cat > $TMPC << EOF
 #include <inttypes.h>
 #include <net/if.h>
 #include <net/netmap.h>
 #include <net/netmap_user.h>
+#if (NETMAP_API < 11) || (NETMAP_API > 15)
+#error
+#endif
 int main(void) { return 0; }
 EOF
   if compile_prog "" "" ; then
diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index 854997d9ba..a1de2f43a0 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -106,7 +106,7 @@ struct vhost_net *vhost_net_init(NetClientState *backend, int devfd,
         goto fail;
     }
     net->nc = backend;
-    net->dev.backend_features = tap_has_vnet_hdr(backend) ? 0 :
+    net->dev.backend_features = qemu_has_vnet_hdr(backend) ? 0 :
         (1 << VHOST_NET_F_VIRTIO_NET_HDR);
     net->backend = r;
 
@@ -117,8 +117,8 @@ struct vhost_net *vhost_net_init(NetClientState *backend, int devfd,
     if (r < 0) {
         goto fail;
     }
-    if (!tap_has_vnet_hdr_len(backend,
-                              sizeof(struct virtio_net_hdr_mrg_rxbuf))) {
+    if (!qemu_has_vnet_hdr_len(backend,
+                               sizeof(struct virtio_net_hdr_mrg_rxbuf))) {
         net->dev.features &= ~(1 << VIRTIO_NET_F_MRG_RXBUF);
     }
     if (~net->dev.features & net->dev.backend_features) {
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 36266083b2..3c0342e17a 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -325,11 +325,7 @@ static void peer_test_vnet_hdr(VirtIONet *n)
         return;
     }
 
-    if (nc->peer->info->type != NET_CLIENT_OPTIONS_KIND_TAP) {
-        return;
-    }
-
-    n->has_vnet_hdr = tap_has_vnet_hdr(nc->peer);
+    n->has_vnet_hdr = qemu_has_vnet_hdr(nc->peer);
 }
 
 static int peer_has_vnet_hdr(VirtIONet *n)
@@ -342,7 +338,7 @@ static int peer_has_ufo(VirtIONet *n)
     if (!peer_has_vnet_hdr(n))
         return 0;
 
-    n->has_ufo = tap_has_ufo(qemu_get_queue(n->nic)->peer);
+    n->has_ufo = qemu_has_ufo(qemu_get_queue(n->nic)->peer);
 
     return n->has_ufo;
 }
@@ -361,8 +357,8 @@ static void virtio_net_set_mrg_rx_bufs(VirtIONet *n, int mergeable_rx_bufs)
         nc = qemu_get_subqueue(n->nic, i);
 
         if (peer_has_vnet_hdr(n) &&
-            tap_has_vnet_hdr_len(nc->peer, n->guest_hdr_len)) {
-            tap_set_vnet_hdr_len(nc->peer, n->guest_hdr_len);
+            qemu_has_vnet_hdr_len(nc->peer, n->guest_hdr_len)) {
+            qemu_set_vnet_hdr_len(nc->peer, n->guest_hdr_len);
             n->host_hdr_len = n->guest_hdr_len;
         }
     }
@@ -463,7 +459,7 @@ static uint32_t virtio_net_bad_features(VirtIODevice *vdev)
 
 static void virtio_net_apply_guest_offloads(VirtIONet *n)
 {
-    tap_set_offload(qemu_get_subqueue(n->nic, 0)->peer,
+    qemu_set_offload(qemu_get_queue(n->nic)->peer,
             !!(n->curr_guest_offloads & (1ULL << VIRTIO_NET_F_GUEST_CSUM)),
             !!(n->curr_guest_offloads & (1ULL << VIRTIO_NET_F_GUEST_TSO4)),
             !!(n->curr_guest_offloads & (1ULL << VIRTIO_NET_F_GUEST_TSO6)),
@@ -1544,7 +1540,7 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp)
     peer_test_vnet_hdr(n);
     if (peer_has_vnet_hdr(n)) {
         for (i = 0; i < n->max_queues; i++) {
-            tap_using_vnet_hdr(qemu_get_subqueue(n->nic, i)->peer, true);
+            qemu_using_vnet_hdr(qemu_get_subqueue(n->nic, i)->peer, true);
         }
         n->host_hdr_len = sizeof(struct virtio_net_hdr);
     } else {
diff --git a/hw/net/vmxnet3.c b/hw/net/vmxnet3.c
index 19687aa03c..5be807ce82 100644
--- a/hw/net/vmxnet3.c
+++ b/hw/net/vmxnet3.c
@@ -1290,12 +1290,12 @@ static void vmxnet3_update_features(VMXNET3State *s)
               s->lro_supported, rxcso_supported,
               s->rx_vlan_stripping);
     if (s->peer_has_vhdr) {
-        tap_set_offload(qemu_get_queue(s->nic)->peer,
-                        rxcso_supported,
-                        s->lro_supported,
-                        s->lro_supported,
-                        0,
-                        0);
+        qemu_set_offload(qemu_get_queue(s->nic)->peer,
+                         rxcso_supported,
+                         s->lro_supported,
+                         s->lro_supported,
+                         0,
+                         0);
     }
 }
 
@@ -1883,11 +1883,9 @@ static NetClientInfo net_vmxnet3_info = {
 
 static bool vmxnet3_peer_has_vnet_hdr(VMXNET3State *s)
 {
-    NetClientState *peer = qemu_get_queue(s->nic)->peer;
+    NetClientState *nc = qemu_get_queue(s->nic);
 
-    if ((NULL != peer)                              &&
-        (peer->info->type == NET_CLIENT_OPTIONS_KIND_TAP)   &&
-        tap_has_vnet_hdr(peer)) {
+    if (qemu_has_vnet_hdr(nc->peer)) {
         return true;
     }
 
@@ -1935,10 +1933,10 @@ static void vmxnet3_net_init(VMXNET3State *s)
     s->lro_supported = false;
 
     if (s->peer_has_vhdr) {
-        tap_set_vnet_hdr_len(qemu_get_queue(s->nic)->peer,
+        qemu_set_vnet_hdr_len(qemu_get_queue(s->nic)->peer,
             sizeof(struct virtio_net_hdr));
 
-        tap_using_vnet_hdr(qemu_get_queue(s->nic)->peer, 1);
+        qemu_using_vnet_hdr(qemu_get_queue(s->nic)->peer, 1);
     }
 
     qemu_format_nic_info_str(qemu_get_queue(s->nic), s->conf.macaddr.a);
diff --git a/include/net/net.h b/include/net/net.h
index 11e146888b..8166345a13 100644
--- a/include/net/net.h
+++ b/include/net/net.h
@@ -50,6 +50,12 @@ typedef void (NetCleanup) (NetClientState *);
 typedef void (LinkStatusChanged)(NetClientState *);
 typedef void (NetClientDestructor)(NetClientState *);
 typedef RxFilterInfo *(QueryRxFilter)(NetClientState *);
+typedef bool (HasUfo)(NetClientState *);
+typedef bool (HasVnetHdr)(NetClientState *);
+typedef bool (HasVnetHdrLen)(NetClientState *, int);
+typedef void (UsingVnetHdr)(NetClientState *, bool);
+typedef void (SetOffload)(NetClientState *, int, int, int, int, int);
+typedef void (SetVnetHdrLen)(NetClientState *, int);
 
 typedef struct NetClientInfo {
     NetClientOptionsKind type;
@@ -62,6 +68,12 @@ typedef struct NetClientInfo {
     LinkStatusChanged *link_status_changed;
     QueryRxFilter *query_rx_filter;
     NetPoll *poll;
+    HasUfo *has_ufo;
+    HasVnetHdr *has_vnet_hdr;
+    HasVnetHdrLen *has_vnet_hdr_len;
+    UsingVnetHdr *using_vnet_hdr;
+    SetOffload *set_offload;
+    SetVnetHdrLen *set_vnet_hdr_len;
 } NetClientInfo;
 
 struct NetClientState {
@@ -120,6 +132,13 @@ ssize_t qemu_send_packet_async(NetClientState *nc, const uint8_t *buf,
 void qemu_purge_queued_packets(NetClientState *nc);
 void qemu_flush_queued_packets(NetClientState *nc);
 void qemu_format_nic_info_str(NetClientState *nc, uint8_t macaddr[6]);
+bool qemu_has_ufo(NetClientState *nc);
+bool qemu_has_vnet_hdr(NetClientState *nc);
+bool qemu_has_vnet_hdr_len(NetClientState *nc, int len);
+void qemu_using_vnet_hdr(NetClientState *nc, bool enable);
+void qemu_set_offload(NetClientState *nc, int csum, int tso4, int tso6,
+                      int ecn, int ufo);
+void qemu_set_vnet_hdr_len(NetClientState *nc, int len);
 void qemu_macaddr_default_if_unset(MACAddr *macaddr);
 int qemu_show_nic_models(const char *arg, const char *const *models);
 void qemu_check_nic_model(NICInfo *nd, const char *model);
diff --git a/include/net/tap.h b/include/net/tap.h
index a994f20447..6daeb42b0f 100644
--- a/include/net/tap.h
+++ b/include/net/tap.h
@@ -29,12 +29,6 @@
 #include "qemu-common.h"
 #include "qapi-types.h"
 
-bool tap_has_ufo(NetClientState *nc);
-int tap_has_vnet_hdr(NetClientState *nc);
-int tap_has_vnet_hdr_len(NetClientState *nc, int len);
-void tap_using_vnet_hdr(NetClientState *nc, bool using_vnet_hdr);
-void tap_set_offload(NetClientState *nc, int csum, int tso4, int tso6, int ecn, int ufo);
-void tap_set_vnet_hdr_len(NetClientState *nc, int len);
 int tap_enable(NetClientState *nc);
 int tap_disable(NetClientState *nc);
 
diff --git a/net/net.c b/net/net.c
index 41b38830ea..e3ef1e4f1d 100644
--- a/net/net.c
+++ b/net/net.c
@@ -378,6 +378,61 @@ void qemu_foreach_nic(qemu_nic_foreach func, void *opaque)
     }
 }
 
+bool qemu_has_ufo(NetClientState *nc)
+{
+    if (!nc || !nc->info->has_ufo) {
+        return false;
+    }
+
+    return nc->info->has_ufo(nc);
+}
+
+bool qemu_has_vnet_hdr(NetClientState *nc)
+{
+    if (!nc || !nc->info->has_vnet_hdr) {
+        return false;
+    }
+
+    return nc->info->has_vnet_hdr(nc);
+}
+
+bool qemu_has_vnet_hdr_len(NetClientState *nc, int len)
+{
+    if (!nc || !nc->info->has_vnet_hdr_len) {
+        return false;
+    }
+
+    return nc->info->has_vnet_hdr_len(nc, len);
+}
+
+void qemu_using_vnet_hdr(NetClientState *nc, bool enable)
+{
+    if (!nc || !nc->info->using_vnet_hdr) {
+        return;
+    }
+
+    nc->info->using_vnet_hdr(nc, enable);
+}
+
+void qemu_set_offload(NetClientState *nc, int csum, int tso4, int tso6,
+                          int ecn, int ufo)
+{
+    if (!nc || !nc->info->set_offload) {
+        return;
+    }
+
+    nc->info->set_offload(nc, csum, tso4, tso6, ecn, ufo);
+}
+
+void qemu_set_vnet_hdr_len(NetClientState *nc, int len)
+{
+    if (!nc || !nc->info->set_vnet_hdr_len) {
+        return;
+    }
+
+    nc->info->set_vnet_hdr_len(nc, len);
+}
+
 int qemu_can_send_packet(NetClientState *sender)
 {
     if (!sender->peer) {
diff --git a/net/netmap.c b/net/netmap.c
index 0ccc4976b5..8213304a5b 100644
--- a/net/netmap.c
+++ b/net/netmap.c
@@ -27,10 +27,13 @@
 #include <net/if.h>
 #include <sys/mman.h>
 #include <stdint.h>
+#include <stdio.h>
+#define NETMAP_WITH_LIBS
 #include <net/netmap.h>
 #include <net/netmap_user.h>
 
 #include "net/net.h"
+#include "net/tap.h"
 #include "clients.h"
 #include "sysemu/sysemu.h"
 #include "qemu/error-report.h"
@@ -54,33 +57,9 @@ typedef struct NetmapState {
     bool                read_poll;
     bool                write_poll;
     struct iovec        iov[IOV_MAX];
+    int                 vnet_hdr_len;  /* Current virtio-net header length. */
 } NetmapState;
 
-#define D(format, ...)                                          \
-    do {                                                        \
-        struct timeval __xxts;                                  \
-        gettimeofday(&__xxts, NULL);                            \
-        printf("%03d.%06d %s [%d] " format "\n",                \
-                (int)__xxts.tv_sec % 1000, (int)__xxts.tv_usec, \
-                __func__, __LINE__, ##__VA_ARGS__);         \
-    } while (0)
-
-/* Rate limited version of "D", lps indicates how many per second */
-#define RD(lps, format, ...)                                    \
-    do {                                                        \
-        static int t0, __cnt;                                   \
-        struct timeval __xxts;                                  \
-        gettimeofday(&__xxts, NULL);                            \
-        if (t0 != __xxts.tv_sec) {                              \
-            t0 = __xxts.tv_sec;                                 \
-            __cnt = 0;                                          \
-        }                                                       \
-        if (__cnt++ < lps) {                                    \
-            D(format, ##__VA_ARGS__);                           \
-        }                                                       \
-    } while (0)
-
-
 #ifndef __FreeBSD__
 #define pkt_copy bcopy
 #else
@@ -237,7 +216,7 @@ static ssize_t netmap_receive(NetClientState *nc,
         return size;
     }
 
-    if (ring->avail == 0) {
+    if (nm_ring_empty(ring)) {
         /* No available slots in the netmap TX ring. */
         netmap_write_poll(s, true);
         return 0;
@@ -250,8 +229,7 @@ static ssize_t netmap_receive(NetClientState *nc,
     ring->slot[i].len = size;
     ring->slot[i].flags = 0;
     pkt_copy(buf, dst, size);
-    ring->cur = NETMAP_RING_NEXT(ring, i);
-    ring->avail--;
+    ring->cur = ring->head = nm_ring_next(ring, i);
     ioctl(s->me.fd, NIOCTXSYNC, NULL);
 
     return size;
@@ -267,17 +245,15 @@ static ssize_t netmap_receive_iov(NetClientState *nc,
     uint8_t *dst;
     int j;
     uint32_t i;
-    uint32_t avail;
 
     if (unlikely(!ring)) {
         /* Drop the packet. */
         return iov_size(iov, iovcnt);
     }
 
-    i = ring->cur;
-    avail = ring->avail;
+    last = i = ring->cur;
 
-    if (avail < iovcnt) {
+    if (nm_ring_space(ring) < iovcnt) {
         /* Not enough netmap slots. */
         netmap_write_poll(s, true);
         return 0;
@@ -293,7 +269,7 @@ static ssize_t netmap_receive_iov(NetClientState *nc,
         while (iov_frag_size) {
             nm_frag_size = MIN(iov_frag_size, ring->nr_buf_size);
 
-            if (unlikely(avail == 0)) {
+            if (unlikely(nm_ring_empty(ring))) {
                 /* We run out of netmap slots while splitting the
                    iovec fragments. */
                 netmap_write_poll(s, true);
@@ -308,8 +284,7 @@ static ssize_t netmap_receive_iov(NetClientState *nc,
             pkt_copy(iov[j].iov_base + offset, dst, nm_frag_size);
 
             last = i;
-            i = NETMAP_RING_NEXT(ring, i);
-            avail--;
+            i = nm_ring_next(ring, i);
 
             offset += nm_frag_size;
             iov_frag_size -= nm_frag_size;
@@ -318,9 +293,8 @@ static ssize_t netmap_receive_iov(NetClientState *nc,
     /* The last slot must not have NS_MOREFRAG set. */
     ring->slot[last].flags &= ~NS_MOREFRAG;
 
-    /* Now update ring->cur and ring->avail. */
-    ring->cur = i;
-    ring->avail = avail;
+    /* Now update ring->cur and ring->head. */
+    ring->cur = ring->head = i;
 
     ioctl(s->me.fd, NIOCTXSYNC, NULL);
 
@@ -343,7 +317,7 @@ static void netmap_send(void *opaque)
 
     /* Keep sending while there are available packets into the netmap
        RX ring and the forwarding path towards the peer is open. */
-    while (ring->avail > 0 && qemu_can_send_packet(&s->nc)) {
+    while (!nm_ring_empty(ring) && qemu_can_send_packet(&s->nc)) {
         uint32_t i;
         uint32_t idx;
         bool morefrag;
@@ -358,11 +332,10 @@ static void netmap_send(void *opaque)
             s->iov[iovcnt].iov_len = ring->slot[i].len;
             iovcnt++;
 
-            ring->cur = NETMAP_RING_NEXT(ring, i);
-            ring->avail--;
-        } while (ring->avail && morefrag);
+            ring->cur = ring->head = nm_ring_next(ring, i);
+        } while (!nm_ring_empty(ring) && morefrag);
 
-        if (unlikely(!ring->avail && morefrag)) {
+        if (unlikely(nm_ring_empty(ring) && morefrag)) {
             RD(5, "[netmap_send] ran out of slots, with a pending"
                    "incomplete packet\n");
         }
@@ -394,6 +367,63 @@ static void netmap_cleanup(NetClientState *nc)
     s->me.fd = -1;
 }
 
+/* Offloading manipulation support callbacks. */
+static bool netmap_has_ufo(NetClientState *nc)
+{
+    return true;
+}
+
+static bool netmap_has_vnet_hdr(NetClientState *nc)
+{
+    return true;
+}
+
+static bool netmap_has_vnet_hdr_len(NetClientState *nc, int len)
+{
+    return len == 0 || len == sizeof(struct virtio_net_hdr) ||
+                len == sizeof(struct virtio_net_hdr_mrg_rxbuf);
+}
+
+static void netmap_using_vnet_hdr(NetClientState *nc, bool enable)
+{
+}
+
+static void netmap_set_vnet_hdr_len(NetClientState *nc, int len)
+{
+    NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
+    int err;
+    struct nmreq req;
+
+    /* Issue a NETMAP_BDG_VNET_HDR command to change the virtio-net header
+     * length for the netmap adapter associated to 'me->ifname'.
+     */
+    memset(&req, 0, sizeof(req));
+    pstrcpy(req.nr_name, sizeof(req.nr_name), s->me.ifname);
+    req.nr_version = NETMAP_API;
+    req.nr_cmd = NETMAP_BDG_VNET_HDR;
+    req.nr_arg1 = len;
+    err = ioctl(s->me.fd, NIOCREGIF, &req);
+    if (err) {
+        error_report("Unable to execute NETMAP_BDG_VNET_HDR on %s: %s",
+                     s->me.ifname, strerror(errno));
+    } else {
+        /* Keep track of the current length. */
+        s->vnet_hdr_len = len;
+    }
+}
+
+static void netmap_set_offload(NetClientState *nc, int csum, int tso4, int tso6,
+                               int ecn, int ufo)
+{
+    NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
+
+    /* Setting a virtio-net header length greater than zero automatically
+     * enables the offloadings.
+     */
+    if (!s->vnet_hdr_len) {
+        netmap_set_vnet_hdr_len(nc, sizeof(struct virtio_net_hdr));
+    }
+}
 
 /* NetClientInfo methods */
 static NetClientInfo net_netmap_info = {
@@ -403,6 +433,12 @@ static NetClientInfo net_netmap_info = {
     .receive_iov = netmap_receive_iov,
     .poll = netmap_poll,
     .cleanup = netmap_cleanup,
+    .has_ufo = netmap_has_ufo,
+    .has_vnet_hdr = netmap_has_vnet_hdr,
+    .has_vnet_hdr_len = netmap_has_vnet_hdr_len,
+    .using_vnet_hdr = netmap_using_vnet_hdr,
+    .set_offload = netmap_set_offload,
+    .set_vnet_hdr_len = netmap_set_vnet_hdr_len,
 };
 
 /* The exported init function
@@ -428,6 +464,7 @@ int net_init_netmap(const NetClientOptions *opts,
     nc = qemu_new_net_client(&net_netmap_info, peer, "netmap", name);
     s = DO_UPCAST(NetmapState, nc, nc);
     s->me = me;
+    s->vnet_hdr_len = 0;
     netmap_read_poll(s, true); /* Initially only poll for reads. */
 
     return 0;
diff --git a/net/tap-win32.c b/net/tap-win32.c
index 91e9e844a0..8aee611f7d 100644
--- a/net/tap-win32.c
+++ b/net/tap-win32.c
@@ -669,11 +669,60 @@ static void tap_win32_send(void *opaque)
     }
 }
 
+static bool tap_has_ufo(NetClientState *nc)
+{
+    return false;
+}
+
+static bool tap_has_vnet_hdr(NetClientState *nc)
+{
+    return false;
+}
+
+int tap_probe_vnet_hdr_len(int fd, int len)
+{
+    return 0;
+}
+
+void tap_fd_set_vnet_hdr_len(int fd, int len)
+{
+}
+
+static void tap_using_vnet_hdr(NetClientState *nc, bool using_vnet_hdr)
+{
+}
+
+static void tap_set_offload(NetClientState *nc, int csum, int tso4,
+                     int tso6, int ecn, int ufo)
+{
+}
+
+struct vhost_net *tap_get_vhost_net(NetClientState *nc)
+{
+    return NULL;
+}
+
+static bool tap_has_vnet_hdr_len(NetClientState *nc, int len)
+{
+    return false;
+}
+
+static void tap_set_vnet_hdr_len(NetClientState *nc, int len)
+{
+    abort();
+}
+
 static NetClientInfo net_tap_win32_info = {
     .type = NET_CLIENT_OPTIONS_KIND_TAP,
     .size = sizeof(TAPState),
     .receive = tap_receive,
     .cleanup = tap_cleanup,
+    .has_ufo = tap_has_ufo,
+    .has_vnet_hdr = tap_has_vnet_hdr,
+    .has_vnet_hdr_len = tap_has_vnet_hdr_len,
+    .using_vnet_hdr = tap_using_vnet_hdr,
+    .set_offload = tap_set_offload,
+    .set_vnet_hdr_len = tap_set_vnet_hdr_len,
 };
 
 static int tap_win32_init(NetClientState *peer, const char *model,
@@ -722,49 +771,6 @@ int net_init_tap(const NetClientOptions *opts, const char *name,
     return 0;
 }
 
-bool tap_has_ufo(NetClientState *nc)
-{
-    return false;
-}
-
-int tap_has_vnet_hdr(NetClientState *nc)
-{
-    return 0;
-}
-
-int tap_probe_vnet_hdr_len(int fd, int len)
-{
-    return 0;
-}
-
-void tap_fd_set_vnet_hdr_len(int fd, int len)
-{
-}
-
-void tap_using_vnet_hdr(NetClientState *nc, bool using_vnet_hdr)
-{
-}
-
-void tap_set_offload(NetClientState *nc, int csum, int tso4,
-                     int tso6, int ecn, int ufo)
-{
-}
-
-struct vhost_net *tap_get_vhost_net(NetClientState *nc)
-{
-    return NULL;
-}
-
-int tap_has_vnet_hdr_len(NetClientState *nc, int len)
-{
-    return 0;
-}
-
-void tap_set_vnet_hdr_len(NetClientState *nc, int len)
-{
-    abort();
-}
-
 int tap_enable(NetClientState *nc)
 {
     abort();
diff --git a/net/tap.c b/net/tap.c
index 39c1cda3e4..2d5099b9be 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -210,7 +210,7 @@ static void tap_send(void *opaque)
     } while (size > 0 && qemu_can_send_packet(&s->nc));
 }
 
-bool tap_has_ufo(NetClientState *nc)
+static bool tap_has_ufo(NetClientState *nc)
 {
     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 
@@ -219,7 +219,7 @@ bool tap_has_ufo(NetClientState *nc)
     return s->has_ufo;
 }
 
-int tap_has_vnet_hdr(NetClientState *nc)
+static bool tap_has_vnet_hdr(NetClientState *nc)
 {
     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 
@@ -228,16 +228,16 @@ int tap_has_vnet_hdr(NetClientState *nc)
     return !!s->host_vnet_hdr_len;
 }
 
-int tap_has_vnet_hdr_len(NetClientState *nc, int len)
+static bool tap_has_vnet_hdr_len(NetClientState *nc, int len)
 {
     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 
     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP);
 
-    return tap_probe_vnet_hdr_len(s->fd, len);
+    return !!tap_probe_vnet_hdr_len(s->fd, len);
 }
 
-void tap_set_vnet_hdr_len(NetClientState *nc, int len)
+static void tap_set_vnet_hdr_len(NetClientState *nc, int len)
 {
     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 
@@ -249,7 +249,7 @@ void tap_set_vnet_hdr_len(NetClientState *nc, int len)
     s->host_vnet_hdr_len = len;
 }
 
-void tap_using_vnet_hdr(NetClientState *nc, bool using_vnet_hdr)
+static void tap_using_vnet_hdr(NetClientState *nc, bool using_vnet_hdr)
 {
     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 
@@ -259,7 +259,7 @@ void tap_using_vnet_hdr(NetClientState *nc, bool using_vnet_hdr)
     s->using_vnet_hdr = using_vnet_hdr;
 }
 
-void tap_set_offload(NetClientState *nc, int csum, int tso4,
+static void tap_set_offload(NetClientState *nc, int csum, int tso4,
                      int tso6, int ecn, int ufo)
 {
     TAPState *s = DO_UPCAST(TAPState, nc, nc);
@@ -314,6 +314,12 @@ static NetClientInfo net_tap_info = {
     .receive_iov = tap_receive_iov,
     .poll = tap_poll,
     .cleanup = tap_cleanup,
+    .has_ufo = tap_has_ufo,
+    .has_vnet_hdr = tap_has_vnet_hdr,
+    .has_vnet_hdr_len = tap_has_vnet_hdr_len,
+    .using_vnet_hdr = tap_using_vnet_hdr,
+    .set_offload = tap_set_offload,
+    .set_vnet_hdr_len = tap_set_vnet_hdr_len,
 };
 
 static TAPState *net_tap_fd_init(NetClientState *peer,