Coverity CID: 1402953 Reviewed by: scottl, markj, aleksandr.fedorov -at- itglobal.com Approved by: vmaffione, jhb Differential Revision: https://reviews.freebsd.org/D20913
808 lines
18 KiB
C
808 lines
18 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2019 Vincenzo Maffione <vmaffione@FreeBSD.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
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* OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* This file implements multiple network backends (tap, netmap, ...),
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* to be used by network frontends such as virtio-net and e1000.
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* The API to access the backend (e.g. send/receive packets, negotiate
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* features) is exported by net_backends.h.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h> /* u_short etc */
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#ifndef WITHOUT_CAPSICUM
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#include <sys/capsicum.h>
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#endif
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#include <sys/ioctl.h>
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#include <sys/mman.h>
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#include <sys/uio.h>
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#include <net/if.h>
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#include <net/netmap.h>
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#include <net/netmap_virt.h>
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#define NETMAP_WITH_LIBS
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#include <net/netmap_user.h>
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#ifndef WITHOUT_CAPSICUM
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#include <capsicum_helpers.h>
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#endif
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <string.h>
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#include <unistd.h>
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#include <sysexits.h>
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#include <assert.h>
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#include <pthread.h>
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#include <pthread_np.h>
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#include <poll.h>
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#include <assert.h>
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#include "iov.h"
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#include "mevent.h"
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#include "net_backends.h"
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#include <sys/linker_set.h>
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/*
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* Each network backend registers a set of function pointers that are
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* used to implement the net backends API.
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* This might need to be exposed if we implement backends in separate files.
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*/
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struct net_backend {
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const char *prefix; /* prefix matching this backend */
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/*
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* Routines used to initialize and cleanup the resources needed
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* by a backend. The cleanup function is used internally,
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* and should not be called by the frontend.
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*/
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int (*init)(struct net_backend *be, const char *devname,
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net_be_rxeof_t cb, void *param);
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void (*cleanup)(struct net_backend *be);
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/*
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* Called to serve a guest transmit request. The scatter-gather
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* vector provided by the caller has 'iovcnt' elements and contains
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* the packet to send.
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*/
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ssize_t (*send)(struct net_backend *be, struct iovec *iov, int iovcnt);
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/*
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* Called to receive a packet from the backend. When the function
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* returns a positive value 'len', the scatter-gather vector
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* provided by the caller contains a packet with such length.
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* The function returns 0 if the backend doesn't have a new packet to
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* receive.
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*/
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ssize_t (*recv)(struct net_backend *be, struct iovec *iov, int iovcnt);
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/*
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* Ask the backend for the virtio-net features it is able to
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* support. Possible features are TSO, UFO and checksum offloading
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* in both rx and tx direction and for both IPv4 and IPv6.
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*/
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uint64_t (*get_cap)(struct net_backend *be);
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/*
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* Tell the backend to enable/disable the specified virtio-net
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* features (capabilities).
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*/
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int (*set_cap)(struct net_backend *be, uint64_t features,
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unsigned int vnet_hdr_len);
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struct pci_vtnet_softc *sc;
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int fd;
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/*
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* Length of the virtio-net header used by the backend and the
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* frontend, respectively. A zero value means that the header
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* is not used.
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*/
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unsigned int be_vnet_hdr_len;
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unsigned int fe_vnet_hdr_len;
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/* Size of backend-specific private data. */
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size_t priv_size;
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/* Room for backend-specific data. */
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char opaque[0];
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};
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SET_DECLARE(net_backend_set, struct net_backend);
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#define VNET_HDR_LEN sizeof(struct virtio_net_rxhdr)
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#define WPRINTF(params) printf params
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/*
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* The tap backend
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*/
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struct tap_priv {
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struct mevent *mevp;
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};
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static void
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tap_cleanup(struct net_backend *be)
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{
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struct tap_priv *priv = (struct tap_priv *)be->opaque;
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if (priv->mevp) {
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mevent_delete(priv->mevp);
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}
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if (be->fd != -1) {
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close(be->fd);
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be->fd = -1;
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}
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}
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static int
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tap_init(struct net_backend *be, const char *devname,
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net_be_rxeof_t cb, void *param)
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{
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struct tap_priv *priv = (struct tap_priv *)be->opaque;
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char tbuf[80];
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int opt = 1;
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#ifndef WITHOUT_CAPSICUM
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cap_rights_t rights;
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#endif
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if (cb == NULL) {
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WPRINTF(("TAP backend requires non-NULL callback\n"));
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return (-1);
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}
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strcpy(tbuf, "/dev/");
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strlcat(tbuf, devname, sizeof(tbuf));
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be->fd = open(tbuf, O_RDWR);
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if (be->fd == -1) {
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WPRINTF(("open of tap device %s failed\n", tbuf));
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goto error;
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}
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/*
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* Set non-blocking and register for read
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* notifications with the event loop
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*/
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if (ioctl(be->fd, FIONBIO, &opt) < 0) {
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WPRINTF(("tap device O_NONBLOCK failed\n"));
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goto error;
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}
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#ifndef WITHOUT_CAPSICUM
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cap_rights_init(&rights, CAP_EVENT, CAP_READ, CAP_WRITE);
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if (caph_rights_limit(be->fd, &rights) == -1)
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errx(EX_OSERR, "Unable to apply rights for sandbox");
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#endif
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priv->mevp = mevent_add(be->fd, EVF_READ, cb, param);
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if (priv->mevp == NULL) {
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WPRINTF(("Could not register event\n"));
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goto error;
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}
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return (0);
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error:
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tap_cleanup(be);
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return (-1);
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}
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/*
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* Called to send a buffer chain out to the tap device
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*/
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static ssize_t
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tap_send(struct net_backend *be, struct iovec *iov, int iovcnt)
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{
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return (writev(be->fd, iov, iovcnt));
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}
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static ssize_t
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tap_recv(struct net_backend *be, struct iovec *iov, int iovcnt)
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{
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ssize_t ret;
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/* Should never be called without a valid tap fd */
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assert(be->fd != -1);
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ret = readv(be->fd, iov, iovcnt);
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if (ret < 0 && errno == EWOULDBLOCK) {
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return (0);
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}
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return (ret);
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}
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static uint64_t
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tap_get_cap(struct net_backend *be)
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{
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return (0); /* no capabilities for now */
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}
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static int
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tap_set_cap(struct net_backend *be, uint64_t features,
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unsigned vnet_hdr_len)
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{
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return ((features || vnet_hdr_len) ? -1 : 0);
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}
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static struct net_backend tap_backend = {
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.prefix = "tap",
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.priv_size = sizeof(struct tap_priv),
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.init = tap_init,
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.cleanup = tap_cleanup,
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.send = tap_send,
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.recv = tap_recv,
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.get_cap = tap_get_cap,
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.set_cap = tap_set_cap,
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};
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/* A clone of the tap backend, with a different prefix. */
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static struct net_backend vmnet_backend = {
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.prefix = "vmnet",
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.priv_size = sizeof(struct tap_priv),
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.init = tap_init,
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.cleanup = tap_cleanup,
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.send = tap_send,
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.recv = tap_recv,
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.get_cap = tap_get_cap,
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.set_cap = tap_set_cap,
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};
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DATA_SET(net_backend_set, tap_backend);
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DATA_SET(net_backend_set, vmnet_backend);
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/*
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* The netmap backend
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*/
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/* The virtio-net features supported by netmap. */
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#define NETMAP_FEATURES (VIRTIO_NET_F_CSUM | VIRTIO_NET_F_HOST_TSO4 | \
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VIRTIO_NET_F_HOST_TSO6 | VIRTIO_NET_F_HOST_UFO | \
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VIRTIO_NET_F_GUEST_CSUM | VIRTIO_NET_F_GUEST_TSO4 | \
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VIRTIO_NET_F_GUEST_TSO6 | VIRTIO_NET_F_GUEST_UFO)
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struct netmap_priv {
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char ifname[IFNAMSIZ];
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struct nm_desc *nmd;
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uint16_t memid;
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struct netmap_ring *rx;
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struct netmap_ring *tx;
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struct mevent *mevp;
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net_be_rxeof_t cb;
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void *cb_param;
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};
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static void
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nmreq_init(struct nmreq *req, char *ifname)
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{
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memset(req, 0, sizeof(*req));
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strlcpy(req->nr_name, ifname, sizeof(req->nr_name));
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req->nr_version = NETMAP_API;
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}
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static int
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netmap_set_vnet_hdr_len(struct net_backend *be, int vnet_hdr_len)
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{
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int err;
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struct nmreq req;
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struct netmap_priv *priv = (struct netmap_priv *)be->opaque;
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nmreq_init(&req, priv->ifname);
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req.nr_cmd = NETMAP_BDG_VNET_HDR;
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req.nr_arg1 = vnet_hdr_len;
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err = ioctl(be->fd, NIOCREGIF, &req);
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if (err) {
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WPRINTF(("Unable to set vnet header length %d\n",
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vnet_hdr_len));
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return (err);
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}
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be->be_vnet_hdr_len = vnet_hdr_len;
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return (0);
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}
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static int
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netmap_has_vnet_hdr_len(struct net_backend *be, unsigned vnet_hdr_len)
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{
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int prev_hdr_len = be->be_vnet_hdr_len;
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int ret;
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if (vnet_hdr_len == prev_hdr_len) {
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return (1);
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}
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ret = netmap_set_vnet_hdr_len(be, vnet_hdr_len);
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if (ret) {
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return (0);
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}
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netmap_set_vnet_hdr_len(be, prev_hdr_len);
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return (1);
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}
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static uint64_t
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netmap_get_cap(struct net_backend *be)
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{
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return (netmap_has_vnet_hdr_len(be, VNET_HDR_LEN) ?
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NETMAP_FEATURES : 0);
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}
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static int
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netmap_set_cap(struct net_backend *be, uint64_t features,
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unsigned vnet_hdr_len)
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{
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return (netmap_set_vnet_hdr_len(be, vnet_hdr_len));
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}
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static int
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netmap_init(struct net_backend *be, const char *devname,
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net_be_rxeof_t cb, void *param)
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{
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struct netmap_priv *priv = (struct netmap_priv *)be->opaque;
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strlcpy(priv->ifname, devname, sizeof(priv->ifname));
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priv->ifname[sizeof(priv->ifname) - 1] = '\0';
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priv->nmd = nm_open(priv->ifname, NULL, NETMAP_NO_TX_POLL, NULL);
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if (priv->nmd == NULL) {
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WPRINTF(("Unable to nm_open(): interface '%s', errno (%s)\n",
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devname, strerror(errno)));
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free(priv);
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return (-1);
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}
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priv->memid = priv->nmd->req.nr_arg2;
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priv->tx = NETMAP_TXRING(priv->nmd->nifp, 0);
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priv->rx = NETMAP_RXRING(priv->nmd->nifp, 0);
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priv->cb = cb;
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priv->cb_param = param;
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be->fd = priv->nmd->fd;
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priv->mevp = mevent_add(be->fd, EVF_READ, cb, param);
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if (priv->mevp == NULL) {
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WPRINTF(("Could not register event\n"));
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return (-1);
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}
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return (0);
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}
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static void
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netmap_cleanup(struct net_backend *be)
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{
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struct netmap_priv *priv = (struct netmap_priv *)be->opaque;
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if (priv->mevp) {
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mevent_delete(priv->mevp);
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}
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if (priv->nmd) {
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nm_close(priv->nmd);
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}
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be->fd = -1;
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}
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static ssize_t
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netmap_send(struct net_backend *be, struct iovec *iov,
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int iovcnt)
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{
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struct netmap_priv *priv = (struct netmap_priv *)be->opaque;
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struct netmap_ring *ring;
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ssize_t totlen = 0;
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int nm_buf_size;
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int nm_buf_len;
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uint32_t head;
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void *nm_buf;
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int j;
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ring = priv->tx;
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head = ring->head;
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if (head == ring->tail) {
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WPRINTF(("No space, drop %zu bytes\n", count_iov(iov, iovcnt)));
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goto txsync;
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}
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nm_buf = NETMAP_BUF(ring, ring->slot[head].buf_idx);
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nm_buf_size = ring->nr_buf_size;
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nm_buf_len = 0;
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for (j = 0; j < iovcnt; j++) {
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int iov_frag_size = iov[j].iov_len;
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void *iov_frag_buf = iov[j].iov_base;
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totlen += iov_frag_size;
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/*
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* Split each iovec fragment over more netmap slots, if
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* necessary.
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*/
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for (;;) {
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int copylen;
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copylen = iov_frag_size < nm_buf_size ? iov_frag_size : nm_buf_size;
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memcpy(nm_buf, iov_frag_buf, copylen);
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iov_frag_buf += copylen;
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iov_frag_size -= copylen;
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nm_buf += copylen;
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nm_buf_size -= copylen;
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nm_buf_len += copylen;
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if (iov_frag_size == 0) {
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break;
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}
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ring->slot[head].len = nm_buf_len;
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ring->slot[head].flags = NS_MOREFRAG;
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head = nm_ring_next(ring, head);
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if (head == ring->tail) {
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/*
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* We ran out of netmap slots while
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* splitting the iovec fragments.
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*/
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WPRINTF(("No space, drop %zu bytes\n",
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count_iov(iov, iovcnt)));
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goto txsync;
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}
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nm_buf = NETMAP_BUF(ring, ring->slot[head].buf_idx);
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nm_buf_size = ring->nr_buf_size;
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nm_buf_len = 0;
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}
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}
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/* Complete the last slot, which must not have NS_MOREFRAG set. */
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ring->slot[head].len = nm_buf_len;
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ring->slot[head].flags = 0;
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head = nm_ring_next(ring, head);
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/* Now update ring->head and ring->cur. */
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ring->head = ring->cur = head;
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txsync:
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ioctl(be->fd, NIOCTXSYNC, NULL);
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return (totlen);
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}
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static ssize_t
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netmap_recv(struct net_backend *be, struct iovec *iov, int iovcnt)
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{
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struct netmap_priv *priv = (struct netmap_priv *)be->opaque;
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struct netmap_slot *slot = NULL;
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struct netmap_ring *ring;
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void *iov_frag_buf;
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int iov_frag_size;
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ssize_t totlen = 0;
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uint32_t head;
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assert(iovcnt);
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ring = priv->rx;
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head = ring->head;
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iov_frag_buf = iov->iov_base;
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iov_frag_size = iov->iov_len;
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do {
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int nm_buf_len;
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void *nm_buf;
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if (head == ring->tail) {
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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\n",
|
|
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 struct net_backend netmap_backend = {
|
|
.prefix = "netmap",
|
|
.priv_size = sizeof(struct netmap_priv),
|
|
.init = netmap_init,
|
|
.cleanup = netmap_cleanup,
|
|
.send = netmap_send,
|
|
.recv = netmap_recv,
|
|
.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,
|
|
.recv = netmap_recv,
|
|
.get_cap = netmap_get_cap,
|
|
.set_cap = netmap_set_cap,
|
|
};
|
|
|
|
DATA_SET(net_backend_set, netmap_backend);
|
|
DATA_SET(net_backend_set, vale_backend);
|
|
|
|
/*
|
|
* Initialize a backend and attach to the frontend.
|
|
* This is called during frontend initialization.
|
|
* @pbe is a pointer to the backend to be initialized
|
|
* @devname is the backend-name as supplied on the command line,
|
|
* e.g. -s 2:0,frontend-name,backend-name[,other-args]
|
|
* @cb is the receive callback supplied by the frontend,
|
|
* and it is invoked in the event loop when a receive
|
|
* event is generated in the hypervisor,
|
|
* @param is a pointer to the frontend, and normally used as
|
|
* the argument for the callback.
|
|
*/
|
|
int
|
|
netbe_init(struct net_backend **ret, const char *devname, net_be_rxeof_t cb,
|
|
void *param)
|
|
{
|
|
struct net_backend **pbe, *nbe, *tbe = NULL;
|
|
int err;
|
|
|
|
/*
|
|
* 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,
|
|
strlen((*pbe)->prefix)) == 0) {
|
|
tbe = *pbe;
|
|
assert(tbe->init != NULL);
|
|
assert(tbe->cleanup != NULL);
|
|
assert(tbe->send != NULL);
|
|
assert(tbe->recv != NULL);
|
|
assert(tbe->get_cap != NULL);
|
|
assert(tbe->set_cap != NULL);
|
|
break;
|
|
}
|
|
}
|
|
|
|
*ret = NULL;
|
|
if (tbe == NULL)
|
|
return (EINVAL);
|
|
nbe = calloc(1, sizeof(*nbe) + tbe->priv_size);
|
|
*nbe = *tbe; /* copy the template */
|
|
nbe->fd = -1;
|
|
nbe->sc = param;
|
|
nbe->be_vnet_hdr_len = 0;
|
|
nbe->fe_vnet_hdr_len = 0;
|
|
|
|
/* Initialize the backend. */
|
|
err = nbe->init(nbe, devname, cb, param);
|
|
if (err) {
|
|
free(nbe);
|
|
return (err);
|
|
}
|
|
|
|
*ret = nbe;
|
|
|
|
return (0);
|
|
}
|
|
|
|
void
|
|
netbe_cleanup(struct net_backend *be)
|
|
{
|
|
|
|
if (be != NULL) {
|
|
be->cleanup(be);
|
|
free(be);
|
|
}
|
|
}
|
|
|
|
uint64_t
|
|
netbe_get_cap(struct net_backend *be)
|
|
{
|
|
|
|
assert(be != NULL);
|
|
return (be->get_cap(be));
|
|
}
|
|
|
|
int
|
|
netbe_set_cap(struct net_backend *be, uint64_t features,
|
|
unsigned vnet_hdr_len)
|
|
{
|
|
int ret;
|
|
|
|
assert(be != NULL);
|
|
|
|
/* There are only three valid lengths, i.e., 0, 10 and 12. */
|
|
if (vnet_hdr_len && vnet_hdr_len != VNET_HDR_LEN
|
|
&& vnet_hdr_len != (VNET_HDR_LEN - sizeof(uint16_t)))
|
|
return (-1);
|
|
|
|
be->fe_vnet_hdr_len = vnet_hdr_len;
|
|
|
|
ret = be->set_cap(be, features, vnet_hdr_len);
|
|
assert(be->be_vnet_hdr_len == 0 ||
|
|
be->be_vnet_hdr_len == be->fe_vnet_hdr_len);
|
|
|
|
return (ret);
|
|
}
|
|
|
|
static __inline struct iovec *
|
|
iov_trim(struct iovec *iov, int *iovcnt, unsigned int tlen)
|
|
{
|
|
struct iovec *riov;
|
|
|
|
/* XXX short-cut: assume first segment is >= tlen */
|
|
assert(iov[0].iov_len >= tlen);
|
|
|
|
iov[0].iov_len -= tlen;
|
|
if (iov[0].iov_len == 0) {
|
|
assert(*iovcnt > 1);
|
|
*iovcnt -= 1;
|
|
riov = &iov[1];
|
|
} else {
|
|
iov[0].iov_base = (void *)((uintptr_t)iov[0].iov_base + tlen);
|
|
riov = &iov[0];
|
|
}
|
|
|
|
return (riov);
|
|
}
|
|
|
|
ssize_t
|
|
netbe_send(struct net_backend *be, struct iovec *iov, int iovcnt)
|
|
{
|
|
|
|
assert(be != NULL);
|
|
if (be->be_vnet_hdr_len != be->fe_vnet_hdr_len) {
|
|
/*
|
|
* The frontend uses a virtio-net header, but the backend
|
|
* does not. We ignore it (as it must be all zeroes) and
|
|
* strip it.
|
|
*/
|
|
assert(be->be_vnet_hdr_len == 0);
|
|
iov = iov_trim(iov, &iovcnt, be->fe_vnet_hdr_len);
|
|
}
|
|
|
|
return (be->send(be, iov, iovcnt));
|
|
}
|
|
|
|
/*
|
|
* Try to read a packet from the backend, without blocking.
|
|
* If no packets are available, return 0. In case of success, return
|
|
* the length of the packet just read. Return -1 in case of errors.
|
|
*/
|
|
ssize_t
|
|
netbe_recv(struct net_backend *be, struct iovec *iov, int iovcnt)
|
|
{
|
|
/* Length of prepended virtio-net header. */
|
|
unsigned int hlen = be->fe_vnet_hdr_len;
|
|
int ret;
|
|
|
|
assert(be != NULL);
|
|
|
|
if (hlen && hlen != be->be_vnet_hdr_len) {
|
|
/*
|
|
* The frontend uses a virtio-net header, but the backend
|
|
* does not. We need to prepend a zeroed header.
|
|
*/
|
|
struct virtio_net_rxhdr *vh;
|
|
|
|
assert(be->be_vnet_hdr_len == 0);
|
|
|
|
/*
|
|
* Get a pointer to the rx header, and use the
|
|
* data immediately following it for the packet buffer.
|
|
*/
|
|
vh = iov[0].iov_base;
|
|
iov = iov_trim(iov, &iovcnt, hlen);
|
|
|
|
/*
|
|
* The only valid field in the rx packet header is the
|
|
* number of buffers if merged rx bufs were negotiated.
|
|
*/
|
|
memset(vh, 0, hlen);
|
|
if (hlen == VNET_HDR_LEN) {
|
|
vh->vrh_bufs = 1;
|
|
}
|
|
}
|
|
|
|
ret = be->recv(be, iov, iovcnt);
|
|
if (ret > 0) {
|
|
ret += hlen;
|
|
}
|
|
|
|
return (ret);
|
|
}
|
|
|
|
/*
|
|
* Read a packet from the backend and discard it.
|
|
* Returns the size of the discarded packet or zero if no packet was available.
|
|
* A negative error code is returned in case of read error.
|
|
*/
|
|
ssize_t
|
|
netbe_rx_discard(struct net_backend *be)
|
|
{
|
|
/*
|
|
* MP note: the dummybuf is only used to discard frames,
|
|
* so there is no need for it to be per-vtnet or locked.
|
|
* We only make it large enough for TSO-sized segment.
|
|
*/
|
|
static uint8_t dummybuf[65536 + 64];
|
|
struct iovec iov;
|
|
|
|
iov.iov_base = dummybuf;
|
|
iov.iov_len = sizeof(dummybuf);
|
|
|
|
return netbe_recv(be, &iov, 1);
|
|
}
|
|
|