1 files changed, 46 insertions, 706 deletions

diff --git a/usr.sbin/bhyve/net_backends.c b/usr.sbin/bhyve/net_backends.c
index ca4c96b10239..2d11c45f217a 100644
--- a/usr.sbin/bhyve/net_backends.c
+++ b/usr.sbin/bhyve/net_backends.c
@@ -1,5 +1,5 @@
 /*-
- * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ * SPDX-License-Identifier: BSD-2-Clause
  *
  * Copyright (c) 2019 Vincenzo Maffione <vmaffione@FreeBSD.org>
  *
@@ -23,8 +23,6 @@
  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
  * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
  * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- * $FreeBSD$
  */
 
 /*
@@ -34,10 +32,7 @@
  * features) is exported by net_backends.h.
  */
 
-#include <sys/cdefs.h>
-__FBSDID("$FreeBSD$");
-
-#include <sys/types.h>		/* u_short etc */
+#include <sys/types.h>
 #ifndef WITHOUT_CAPSICUM
 #include <sys/capsicum.h>
 #endif
@@ -46,168 +41,39 @@ __FBSDID("$FreeBSD$");
 #include <sys/uio.h>
 
 #include <net/if.h>
-#if defined(INET6) || defined(INET)
 #include <net/if_tap.h>
-#endif
-#include <net/netmap.h>
-#include <net/netmap_virt.h>
-#define NETMAP_WITH_LIBS
-#include <net/netmap_user.h>
 
+#include <assert.h>
 #ifndef WITHOUT_CAPSICUM
 #include <capsicum_helpers.h>
 #endif
 #include <err.h>
 #include <errno.h>
 #include <fcntl.h>
+#include <poll.h>
+#include <pthread.h>
+#include <pthread_np.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
 #include <string.h>
-#include <unistd.h>
 #include <sysexits.h>
-#include <assert.h>
-#include <pthread.h>
-#include <pthread_np.h>
-#include <poll.h>
-#include <assert.h>
-
-#ifdef NETGRAPH
-#include <sys/param.h>
-#include <sys/sysctl.h>
-#include <netgraph.h>
-#endif
+#include <unistd.h>
 
 #include "config.h"
 #include "debug.h"
 #include "iov.h"
 #include "mevent.h"
 #include "net_backends.h"
+#include "net_backends_priv.h"
 #include "pci_emul.h"
 
-#include <sys/linker_set.h>
-
-/*
- * Each network backend registers a set of function pointers that are
- * used to implement the net backends API.
- * This might need to be exposed if we implement backends in separate files.
- */
-struct net_backend {
-	const char *prefix;	/* prefix matching this backend */
-
-	/*
-	 * Routines used to initialize and cleanup the resources needed
-	 * by a backend. The cleanup function is used internally,
-	 * and should not be called by the frontend.
-	 */
-	int (*init)(struct net_backend *be, const char *devname,
-	    nvlist_t *nvl, net_be_rxeof_t cb, void *param);
-	void (*cleanup)(struct net_backend *be);
-
-	/*
-	 * Called to serve a guest transmit request. The scatter-gather
-	 * vector provided by the caller has 'iovcnt' elements and contains
-	 * the packet to send.
-	 */
-	ssize_t (*send)(struct net_backend *be, const struct iovec *iov,
-	    int iovcnt);
-
-	/*
-	 * Get the length of the next packet that can be received from
-	 * the backend. If no packets are currently available, this
-	 * function returns 0.
-	 */
-	ssize_t (*peek_recvlen)(struct net_backend *be);
-
-	/*
-	 * Called to receive a packet from the backend. When the function
-	 * returns a positive value 'len', the scatter-gather vector
-	 * provided by the caller contains a packet with such length.
-	 * The function returns 0 if the backend doesn't have a new packet to
-	 * receive.
-	 */
-	ssize_t (*recv)(struct net_backend *be, const struct iovec *iov,
-	    int iovcnt);
+#define	NET_BE_SIZE(be)		(sizeof(*be) + (be)->priv_size)
 
-	/*
-	 * Ask the backend to enable or disable receive operation in the
-	 * backend. On return from a disable operation, it is guaranteed
-	 * that the receive callback won't be called until receive is
-	 * enabled again. Note however that it is up to the caller to make
-	 * sure that netbe_recv() is not currently being executed by another
-	 * thread.
-	 */
-	void (*recv_enable)(struct net_backend *be);
-	void (*recv_disable)(struct net_backend *be);
-
-	/*
-	 * Ask the backend for the virtio-net features it is able to
-	 * support. Possible features are TSO, UFO and checksum offloading
-	 * in both rx and tx direction and for both IPv4 and IPv6.
-	 */
-	uint64_t (*get_cap)(struct net_backend *be);
-
-	/*
-	 * Tell the backend to enable/disable the specified virtio-net
-	 * features (capabilities).
-	 */
-	int (*set_cap)(struct net_backend *be, uint64_t features,
-	    unsigned int vnet_hdr_len);
-
-	struct pci_vtnet_softc *sc;
-	int fd;
-
-	/*
-	 * Length of the virtio-net header used by the backend and the
-	 * frontend, respectively. A zero value means that the header
-	 * is not used.
-	 */
-	unsigned int be_vnet_hdr_len;
-	unsigned int fe_vnet_hdr_len;
-
-	/* Size of backend-specific private data. */
-	size_t priv_size;
-
-	/* Room for backend-specific data. */
-	char opaque[0];
-};
-
-SET_DECLARE(net_backend_set, struct net_backend);
-
-#define VNET_HDR_LEN	sizeof(struct virtio_net_rxhdr)
-
-#define WPRINTF(params) PRINTLN params
-
-/*
- * The tap backend
- */
-
-#if defined(INET6) || defined(INET)
-const int pf_list[] = {
-#if defined(INET6)
-	PF_INET6,
-#endif
-#if defined(INET)
-	PF_INET,
-#endif
-};
-#endif
-
-struct tap_priv {
-	struct mevent *mevp;
-	/*
-	 * A bounce buffer that allows us to implement the peek_recvlen
-	 * callback. In the future we may get the same information from
-	 * the kevent data.
-	 */
-	char bbuf[1 << 16];
-	ssize_t bbuflen;
-};
-
-static void
+void
 tap_cleanup(struct net_backend *be)
 {
-	struct tap_priv *priv = (struct tap_priv *)be->opaque;
+	struct tap_priv *priv = NET_BE_PRIV(be);
 
 	if (priv->mevp) {
 		mevent_delete(priv->mevp);
@@ -220,21 +86,18 @@ tap_cleanup(struct net_backend *be)
 
 static int
 tap_init(struct net_backend *be, const char *devname,
-	 nvlist_t *nvl, net_be_rxeof_t cb, void *param)
+    nvlist_t *nvl __unused, net_be_rxeof_t cb, void *param)
 {
-	struct tap_priv *priv = (struct tap_priv *)be->opaque;
+	struct tap_priv *priv = NET_BE_PRIV(be);
 	char tbuf[80];
-	int opt = 1;
-#if defined(INET6) || defined(INET)
-	struct ifreq ifrq;
-	int i, s;
-#endif
+	int opt = 1, up = IFF_UP;
+
 #ifndef WITHOUT_CAPSICUM
 	cap_rights_t rights;
 #endif
 
 	if (cb == NULL) {
-		WPRINTF(("TAP backend requires non-NULL callback"));
+		EPRINTLN("TAP backend requires non-NULL callback");
 		return (-1);
 	}
 
@@ -243,7 +106,7 @@ tap_init(struct net_backend *be, const char *devname,
 
 	be->fd = open(tbuf, O_RDWR);
 	if (be->fd == -1) {
-		WPRINTF(("open of tap device %s failed", tbuf));
+		EPRINTLN("open of tap device %s failed", tbuf);
 		goto error;
 	}
 
@@ -252,42 +115,14 @@ tap_init(struct net_backend *be, const char *devname,
 	 * notifications with the event loop
 	 */
 	if (ioctl(be->fd, FIONBIO, &opt) < 0) {
-		WPRINTF(("tap device O_NONBLOCK failed"));
-		goto error;
-	}
-
-#if defined(INET6) || defined(INET)
-	/*
-	 * Try to UP the interface rather than relying on
-	 * net.link.tap.up_on_open.
-	  */
-	bzero(&ifrq, sizeof(ifrq));
-	if (ioctl(be->fd, TAPGIFNAME, &ifrq) < 0) {
-		WPRINTF(("Could not get interface name"));
-		goto error;
-	}
-
-	s = -1;
-	for (i = 0; s == -1 && i < nitems(pf_list); i++)
-		s = socket(pf_list[i], SOCK_DGRAM, 0);
-	if (s == -1) {
-		WPRINTF(("Could open socket"));
+		EPRINTLN("tap device O_NONBLOCK failed");
 		goto error;
 	}
 
-	if (ioctl(s, SIOCGIFFLAGS, &ifrq) < 0) {
-		(void)close(s);
-		WPRINTF(("Could not get interface flags"));
-		goto error;
-	}
-	ifrq.ifr_flags |= IFF_UP;
-	if (ioctl(s, SIOCSIFFLAGS, &ifrq) < 0) {
-		(void)close(s);
-		WPRINTF(("Could not set interface flags"));
+	if (ioctl(be->fd, VMIO_SIOCSIFFLAGS, up)) {
+		EPRINTLN("tap device link up failed");
 		goto error;
 	}
-	(void)close(s);
-#endif
 
 #ifndef WITHOUT_CAPSICUM
 	cap_rights_init(&rights, CAP_EVENT, CAP_READ, CAP_WRITE);
@@ -300,7 +135,7 @@ tap_init(struct net_backend *be, const char *devname,
 
 	priv->mevp = mevent_add_disabled(be->fd, EVF_READ, cb, param);
 	if (priv->mevp == NULL) {
-		WPRINTF(("Could not register event"));
+		EPRINTLN("Could not register event");
 		goto error;
 	}
 
@@ -314,16 +149,16 @@ error:
 /*
  * Called to send a buffer chain out to the tap device
  */
-static ssize_t
+ssize_t
 tap_send(struct net_backend *be, const struct iovec *iov, int iovcnt)
 {
 	return (writev(be->fd, iov, iovcnt));
 }
 
-static ssize_t
+ssize_t
 tap_peek_recvlen(struct net_backend *be)
 {
-	struct tap_priv *priv = (struct tap_priv *)be->opaque;
+	struct tap_priv *priv = NET_BE_PRIV(be);
 	ssize_t ret;
 
 	if (priv->bbuflen > 0) {
@@ -350,10 +185,10 @@ tap_peek_recvlen(struct net_backend *be)
 	return (ret);
 }
 
-static ssize_t
+ssize_t
 tap_recv(struct net_backend *be, const struct iovec *iov, int iovcnt)
 {
-	struct tap_priv *priv = (struct tap_priv *)be->opaque;
+	struct tap_priv *priv = NET_BE_PRIV(be);
 	ssize_t ret;
 
 	if (priv->bbuflen > 0) {
@@ -378,32 +213,32 @@ tap_recv(struct net_backend *be, const struct iovec *iov, int iovcnt)
 	return (ret);
 }
 
-static void
+void
 tap_recv_enable(struct net_backend *be)
 {
-	struct tap_priv *priv = (struct tap_priv *)be->opaque;
+	struct tap_priv *priv = NET_BE_PRIV(be);
 
 	mevent_enable(priv->mevp);
 }
 
-static void
+void
 tap_recv_disable(struct net_backend *be)
 {
-	struct tap_priv *priv = (struct tap_priv *)be->opaque;
+	struct tap_priv *priv = NET_BE_PRIV(be);
 
 	mevent_disable(priv->mevp);
 }
 
-static uint64_t
-tap_get_cap(struct net_backend *be)
+uint64_t
+tap_get_cap(struct net_backend *be __unused)
 {
 
 	return (0); /* no capabilities for now */
 }
 
-static int
-tap_set_cap(struct net_backend *be, uint64_t features,
-		unsigned vnet_hdr_len)
+int
+tap_set_cap(struct net_backend *be __unused, uint64_t features,
+    unsigned vnet_hdr_len)
 {
 
 	return ((features || vnet_hdr_len) ? -1 : 0);
@@ -441,509 +276,6 @@ static struct net_backend vmnet_backend = {
 DATA_SET(net_backend_set, tap_backend);
 DATA_SET(net_backend_set, vmnet_backend);
 
-#ifdef NETGRAPH
-
-/*
- * Netgraph backend
- */
-
-#define NG_SBUF_MAX_SIZE (4 * 1024 * 1024)
-
-static int
-ng_init(struct net_backend *be, const char *devname,
-	 nvlist_t *nvl, net_be_rxeof_t cb, void *param)
-{
-	struct tap_priv *p = (struct tap_priv *)be->opaque;
-	struct ngm_connect ngc;
-	const char *value, *nodename;
-	int sbsz;
-	int ctrl_sock;
-	int flags;
-	unsigned long maxsbsz;
-	size_t msbsz;
-#ifndef WITHOUT_CAPSICUM
-	cap_rights_t rights;
-#endif
-
-	if (cb == NULL) {
-		WPRINTF(("Netgraph backend requires non-NULL callback"));
-		return (-1);
-	}
-
-	be->fd = -1;
-
-	memset(&ngc, 0, sizeof(ngc));
-
-	value = get_config_value_node(nvl, "path");
-	if (value == NULL) {
-		WPRINTF(("path must be provided"));
-		return (-1);
-	}
-	strncpy(ngc.path, value, NG_PATHSIZ - 1);
-
-	value = get_config_value_node(nvl, "hook");
-	if (value == NULL)
-		value = "vmlink";
-	strncpy(ngc.ourhook, value, NG_HOOKSIZ - 1);
-
-	value = get_config_value_node(nvl, "peerhook");
-	if (value == NULL) {
-		WPRINTF(("peer hook must be provided"));
-		return (-1);
-	}
-	strncpy(ngc.peerhook, value, NG_HOOKSIZ - 1);
-
-	nodename = get_config_value_node(nvl, "socket");
-	if (NgMkSockNode(nodename,
-		&ctrl_sock, &be->fd) < 0) {
-		WPRINTF(("can't get Netgraph sockets"));
-		return (-1);
-	}
-
-	if (NgSendMsg(ctrl_sock, ".",
-		NGM_GENERIC_COOKIE,
-		NGM_CONNECT, &ngc, sizeof(ngc)) < 0) {
-		WPRINTF(("can't connect to node"));
-		close(ctrl_sock);
-		goto error;
-	}
-
-	close(ctrl_sock);
-
-	flags = fcntl(be->fd, F_GETFL);
-
-	if (flags < 0) {
-		WPRINTF(("can't get socket flags"));
-		goto error;
-	}
-
-	if (fcntl(be->fd, F_SETFL, flags | O_NONBLOCK) < 0) {
-		WPRINTF(("can't set O_NONBLOCK flag"));
-		goto error;
-	}
-
-	/*
-	 * The default ng_socket(4) buffer's size is too low.
-	 * Calculate the minimum value between NG_SBUF_MAX_SIZE
-	 * and kern.ipc.maxsockbuf.
-	 */
-	msbsz = sizeof(maxsbsz);
-	if (sysctlbyname("kern.ipc.maxsockbuf", &maxsbsz, &msbsz,
-		NULL, 0) < 0) {
-		WPRINTF(("can't get 'kern.ipc.maxsockbuf' value"));
-		goto error;
-	}
-
-	/*
-	 * We can't set the socket buffer size to kern.ipc.maxsockbuf value,
-	 * as it takes into account the mbuf(9) overhead.
-	 */
-	maxsbsz = maxsbsz * MCLBYTES / (MSIZE + MCLBYTES);
-
-	sbsz = MIN(NG_SBUF_MAX_SIZE, maxsbsz);
-
-	if (setsockopt(be->fd, SOL_SOCKET, SO_SNDBUF, &sbsz,
-		sizeof(sbsz)) < 0) {
-		WPRINTF(("can't set TX buffer size"));
-		goto error;
-	}
-
-	if (setsockopt(be->fd, SOL_SOCKET, SO_RCVBUF, &sbsz,
-		sizeof(sbsz)) < 0) {
-		WPRINTF(("can't set RX buffer size"));
-		goto error;
-	}
-
-#ifndef WITHOUT_CAPSICUM
-	cap_rights_init(&rights, CAP_EVENT, CAP_READ, CAP_WRITE);
-	if (caph_rights_limit(be->fd, &rights) == -1)
-		errx(EX_OSERR, "Unable to apply rights for sandbox");
-#endif
-
-	memset(p->bbuf, 0, sizeof(p->bbuf));
-	p->bbuflen = 0;
-
-	p->mevp = mevent_add_disabled(be->fd, EVF_READ, cb, param);
-	if (p->mevp == NULL) {
-		WPRINTF(("Could not register event"));
-		goto error;
-	}
-
-	return (0);
-
-error:
-	tap_cleanup(be);
-	return (-1);
-}
-
-static struct net_backend ng_backend = {
-	.prefix = "netgraph",
-	.priv_size = sizeof(struct tap_priv),
-	.init = ng_init,
-	.cleanup = tap_cleanup,
-	.send = tap_send,
-	.peek_recvlen = tap_peek_recvlen,
-	.recv = tap_recv,
-	.recv_enable = tap_recv_enable,
-	.recv_disable = tap_recv_disable,
-	.get_cap = tap_get_cap,
-	.set_cap = tap_set_cap,
-};
-
-DATA_SET(net_backend_set, ng_backend);
-
-#endif /* NETGRAPH */
-
-/*
- * The netmap backend
- */
-
-/* The virtio-net features supported by netmap. */
-#define NETMAP_FEATURES (VIRTIO_NET_F_CSUM | VIRTIO_NET_F_HOST_TSO4 | \
-		VIRTIO_NET_F_HOST_TSO6 | VIRTIO_NET_F_HOST_UFO | \
-		VIRTIO_NET_F_GUEST_CSUM | VIRTIO_NET_F_GUEST_TSO4 | \
-		VIRTIO_NET_F_GUEST_TSO6 | VIRTIO_NET_F_GUEST_UFO)
-
-struct netmap_priv {
-	char ifname[IFNAMSIZ];
-	struct nm_desc *nmd;
-	uint16_t memid;
-	struct netmap_ring *rx;
-	struct netmap_ring *tx;
-	struct mevent *mevp;
-	net_be_rxeof_t cb;
-	void *cb_param;
-};
-
-static void
-nmreq_init(struct nmreq *req, char *ifname)
-{
-
-	memset(req, 0, sizeof(*req));
-	strlcpy(req->nr_name, ifname, sizeof(req->nr_name));
-	req->nr_version = NETMAP_API;
-}
-
-static int
-netmap_set_vnet_hdr_len(struct net_backend *be, int vnet_hdr_len)
-{
-	int err;
-	struct nmreq req;
-	struct netmap_priv *priv = (struct netmap_priv *)be->opaque;
-
-	nmreq_init(&req, priv->ifname);
-	req.nr_cmd = NETMAP_BDG_VNET_HDR;
-	req.nr_arg1 = vnet_hdr_len;
-	err = ioctl(be->fd, NIOCREGIF, &req);
-	if (err) {
-		WPRINTF(("Unable to set vnet header length %d",
-				vnet_hdr_len));
-		return (err);
-	}
-
-	be->be_vnet_hdr_len = vnet_hdr_len;
-
-	return (0);
-}
-
-static int
-netmap_has_vnet_hdr_len(struct net_backend *be, unsigned vnet_hdr_len)
-{
-	int prev_hdr_len = be->be_vnet_hdr_len;
-	int ret;
-
-	if (vnet_hdr_len == prev_hdr_len) {
-		return (1);
-	}
-
-	ret = netmap_set_vnet_hdr_len(be, vnet_hdr_len);
-	if (ret) {
-		return (0);
-	}
-
-	netmap_set_vnet_hdr_len(be, prev_hdr_len);
-
-	return (1);
-}
-
-static uint64_t
-netmap_get_cap(struct net_backend *be)
-{
-
-	return (netmap_has_vnet_hdr_len(be, VNET_HDR_LEN) ?
-	    NETMAP_FEATURES : 0);
-}
-
-static int
-netmap_set_cap(struct net_backend *be, uint64_t features,
-	       unsigned vnet_hdr_len)
-{
-
-	return (netmap_set_vnet_hdr_len(be, vnet_hdr_len));
-}
-
-static int
-netmap_init(struct net_backend *be, const char *devname,
-	    nvlist_t *nvl, net_be_rxeof_t cb, void *param)
-{
-	struct netmap_priv *priv = (struct netmap_priv *)be->opaque;
-
-	strlcpy(priv->ifname, devname, sizeof(priv->ifname));
-	priv->ifname[sizeof(priv->ifname) - 1] = '\0';
-
-	priv->nmd = nm_open(priv->ifname, NULL, NETMAP_NO_TX_POLL, NULL);
-	if (priv->nmd == NULL) {
-		WPRINTF(("Unable to nm_open(): interface '%s', errno (%s)",
-			devname, strerror(errno)));
-		free(priv);
-		return (-1);
-	}
-
-	priv->memid = priv->nmd->req.nr_arg2;
-	priv->tx = NETMAP_TXRING(priv->nmd->nifp, 0);
-	priv->rx = NETMAP_RXRING(priv->nmd->nifp, 0);
-	priv->cb = cb;
-	priv->cb_param = param;
-	be->fd = priv->nmd->fd;
-
-	priv->mevp = mevent_add_disabled(be->fd, EVF_READ, cb, param);
-	if (priv->mevp == NULL) {
-		WPRINTF(("Could not register event"));
-		return (-1);
-	}
-
-	return (0);
-}
-
-static void
-netmap_cleanup(struct net_backend *be)
-{
-	struct netmap_priv *priv = (struct netmap_priv *)be->opaque;
-
-	if (priv->mevp) {
-		mevent_delete(priv->mevp);
-	}
-	if (priv->nmd) {
-		nm_close(priv->nmd);
-	}
-	be->fd = -1;
-}
-
-static ssize_t
-netmap_send(struct net_backend *be, const struct iovec *iov,
-	    int iovcnt)
-{
-	struct netmap_priv *priv = (struct netmap_priv *)be->opaque;
-	struct netmap_ring *ring;
-	ssize_t totlen = 0;
-	int nm_buf_size;
-	int nm_buf_len;
-	uint32_t head;
-	void *nm_buf;
-	int j;
-
-	ring = priv->tx;
-	head = ring->head;
-	if (head == ring->tail) {
-		WPRINTF(("No space, drop %zu bytes", count_iov(iov, iovcnt)));
-		goto txsync;
-	}
-	nm_buf = NETMAP_BUF(ring, ring->slot[head].buf_idx);
-	nm_buf_size = ring->nr_buf_size;
-	nm_buf_len = 0;
-
-	for (j = 0; j < iovcnt; j++) {
-		int iov_frag_size = iov[j].iov_len;
-		void *iov_frag_buf = iov[j].iov_base;
-
-		totlen += iov_frag_size;
-
-		/*
-		 * Split each iovec fragment over more netmap slots, if
-		 * necessary.
-		 */
-		for (;;) {
-			int copylen;
-
-			copylen = iov_frag_size < nm_buf_size ? iov_frag_size : nm_buf_size;
-			memcpy(nm_buf, iov_frag_buf, copylen);
-
-			iov_frag_buf += copylen;
-			iov_frag_size -= copylen;
-			nm_buf += copylen;
-			nm_buf_size -= copylen;
-			nm_buf_len += copylen;
-
-			if (iov_frag_size == 0) {
-				break;
-			}
-
-			ring->slot[head].len = nm_buf_len;
-			ring->slot[head].flags = NS_MOREFRAG;
-			head = nm_ring_next(ring, head);
-			if (head == ring->tail) {
-				/*
-				 * We ran out of netmap slots while
-				 * splitting the iovec fragments.
-				 */
-				WPRINTF(("No space, drop %zu bytes",
-				   count_iov(iov, iovcnt)));
-				goto txsync;
-			}
-			nm_buf = NETMAP_BUF(ring, ring->slot[head].buf_idx);
-			nm_buf_size = ring->nr_buf_size;
-			nm_buf_len = 0;
-		}
-	}
-
-	/* Complete the last slot, which must not have NS_MOREFRAG set. */
-	ring->slot[head].len = nm_buf_len;
-	ring->slot[head].flags = 0;
-	head = nm_ring_next(ring, head);
-
-	/* Now update ring->head and ring->cur. */
-	ring->head = ring->cur = head;
-txsync:
-	ioctl(be->fd, NIOCTXSYNC, NULL);
-
-	return (totlen);
-}
-
-static ssize_t
-netmap_peek_recvlen(struct net_backend *be)
-{
-	struct netmap_priv *priv = (struct netmap_priv *)be->opaque;
-	struct netmap_ring *ring = priv->rx;
-	uint32_t head = ring->head;
-	ssize_t totlen = 0;
-
-	while (head != ring->tail) {
-		struct netmap_slot *slot = ring->slot + head;
-
-		totlen += slot->len;
-		if ((slot->flags & NS_MOREFRAG) == 0)
-			break;
-		head = nm_ring_next(ring, head);
-	}
-
-	return (totlen);
-}
-
-static ssize_t
-netmap_recv(struct net_backend *be, const struct iovec *iov, int iovcnt)
-{
-	struct netmap_priv *priv = (struct netmap_priv *)be->opaque;
-	struct netmap_slot *slot = NULL;
-	struct netmap_ring *ring;
-	void *iov_frag_buf;
-	int iov_frag_size;
-	ssize_t totlen = 0;
-	uint32_t head;
-
-	assert(iovcnt);
-
-	ring = priv->rx;
-	head = ring->head;
-	iov_frag_buf = iov->iov_base;
-	iov_frag_size = iov->iov_len;
-
-	do {
-		int nm_buf_len;
-		void *nm_buf;
-
-		if (head == ring->tail) {
-			return (0);
-		}
-
-		slot = ring->slot + head;
-		nm_buf = NETMAP_BUF(ring, slot->buf_idx);
-		nm_buf_len = slot->len;
-
-		for (;;) {
-			int copylen = nm_buf_len < iov_frag_size ?
-			    nm_buf_len : iov_frag_size;
-
-			memcpy(iov_frag_buf, nm_buf, copylen);
-			nm_buf += copylen;
-			nm_buf_len -= copylen;
-			iov_frag_buf += copylen;
-			iov_frag_size -= copylen;
-			totlen += copylen;
-
-			if (nm_buf_len == 0) {
-				break;
-			}
-
-			iov++;
-			iovcnt--;
-			if (iovcnt == 0) {
-				/* No space to receive. */
-				WPRINTF(("Short iov, drop %zd bytes",
-				    totlen));
-				return (-ENOSPC);
-			}
-			iov_frag_buf = iov->iov_base;
-			iov_frag_size = iov->iov_len;
-		}
-
-		head = nm_ring_next(ring, head);
-
-	} while (slot->flags & NS_MOREFRAG);
-
-	/* Release slots to netmap. */
-	ring->head = ring->cur = head;
-
-	return (totlen);
-}
-
-static void
-netmap_recv_enable(struct net_backend *be)
-{
-	struct netmap_priv *priv = (struct netmap_priv *)be->opaque;
-
-	mevent_enable(priv->mevp);
-}
-
-static void
-netmap_recv_disable(struct net_backend *be)
-{
-	struct netmap_priv *priv = (struct netmap_priv *)be->opaque;
-
-	mevent_disable(priv->mevp);
-}
-
-static struct net_backend netmap_backend = {
-	.prefix = "netmap",
-	.priv_size = sizeof(struct netmap_priv),
-	.init = netmap_init,
-	.cleanup = netmap_cleanup,
-	.send = netmap_send,
-	.peek_recvlen = netmap_peek_recvlen,
-	.recv = netmap_recv,
-	.recv_enable = netmap_recv_enable,
-	.recv_disable = netmap_recv_disable,
-	.get_cap = netmap_get_cap,
-	.set_cap = netmap_set_cap,
-};
-
-/* A clone of the netmap backend, with a different prefix. */
-static struct net_backend vale_backend = {
-	.prefix = "vale",
-	.priv_size = sizeof(struct netmap_priv),
-	.init = netmap_init,
-	.cleanup = netmap_cleanup,
-	.send = netmap_send,
-	.peek_recvlen = netmap_peek_recvlen,
-	.recv = netmap_recv,
-	.recv_enable = netmap_recv_enable,
-	.recv_disable = netmap_recv_disable,
-	.get_cap = netmap_get_cap,
-	.set_cap = netmap_set_cap,
-};
-
-DATA_SET(net_backend_set, netmap_backend);
-DATA_SET(net_backend_set, vale_backend);
-
 int
 netbe_legacy_config(nvlist_t *nvl, const char *opts)
 {
@@ -980,7 +312,7 @@ netbe_init(struct net_backend **ret, nvlist_t *nvl, net_be_rxeof_t cb,
     void *param)
 {
 	struct net_backend **pbe, *nbe, *tbe = NULL;
-	const char *value;
+	const char *value, *type;
 	char *devname;
 	int err;
 
@@ -991,11 +323,19 @@ netbe_init(struct net_backend **ret, nvlist_t *nvl, net_be_rxeof_t cb,
 	devname = strdup(value);
 
 	/*
+	 * Use the type given by configuration if exists; otherwise
+	 * use the prefix of the backend as the type.
+	 */
+	type = get_config_value_node(nvl, "type");
+	if (type == NULL)
+		type = devname;
+
+	/*
 	 * Find the network backend that matches the user-provided
 	 * device name. net_backend_set is built using a linker set.
 	 */
 	SET_FOREACH(pbe, net_backend_set) {
-		if (strncmp(devname, (*pbe)->prefix,
+		if (strncmp(type, (*pbe)->prefix,
 		    strlen((*pbe)->prefix)) == 0) {
 			tbe = *pbe;
 			assert(tbe->init != NULL);
@@ -1014,7 +354,7 @@ netbe_init(struct net_backend **ret, nvlist_t *nvl, net_be_rxeof_t cb,
 		return (EINVAL);
 	}
 
-	nbe = calloc(1, sizeof(*nbe) + tbe->priv_size);
+	nbe = calloc(1, NET_BE_SIZE(tbe));
 	*nbe = *tbe;	/* copy the template */
 	nbe->fd = -1;
 	nbe->sc = param;