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usr.sbin/bhyve/mmio/net_backends.c

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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2019 Vincenzo Maffione <vmaffione@FreeBSD.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
* OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* 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.
*
* $FreeBSD$
*/
/*
* This file implements multiple network backends (tap, netmap, ...),
* to be used by network frontends such as virtio-net and e1000.
* The API to access the backend (e.g. send/receive packets, negotiate
* features) is exported by net_backends.h.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h> /* u_short etc */
#ifndef WITHOUT_CAPSICUM
#include <sys/capsicum.h>
#endif
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/uio.h>
#include <net/if.h>
#include <net/netmap.h>
#include <net/netmap_virt.h>
#define NETMAP_WITH_LIBS
#include <net/netmap_user.h>
#ifndef WITHOUT_CAPSICUM
#include <capsicum_helpers.h>
#endif
#include <err.h>
#include <errno.h>
#include <fcntl.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 "debug.h"
#include "iov.h"
#include "mevent.h"
#include "net_backends.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,
const char *opts, 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);
/*
* 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
*/
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
tap_cleanup(struct net_backend *be)
{
struct tap_priv *priv = (struct tap_priv *)be->opaque;
if (priv->mevp) {
mevent_delete(priv->mevp);
}
if (be->fd != -1) {
close(be->fd);
be->fd = -1;
}
}
static int
tap_init(struct net_backend *be, const char *devname,
const char *opts, net_be_rxeof_t cb, void *param)
{
struct tap_priv *priv = (struct tap_priv *)be->opaque;
char tbuf[80];
int opt = 1;
#ifndef WITHOUT_CAPSICUM
cap_rights_t rights;
#endif
if (cb == NULL) {
WPRINTF(("TAP backend requires non-NULL callback"));
return (-1);
}
strcpy(tbuf, "/dev/");
strlcat(tbuf, devname, sizeof(tbuf));
be->fd = open(tbuf, O_RDWR);
if (be->fd == -1) {
WPRINTF(("open of tap device %s failed", tbuf));
goto error;
}
/*
* Set non-blocking and register for read
* notifications with the event loop
*/
if (ioctl(be->fd, FIONBIO, &opt) < 0) {
WPRINTF(("tap device O_NONBLOCK failed"));
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(priv->bbuf, 0, sizeof(priv->bbuf));
priv->bbuflen = 0;
priv->mevp = mevent_add_disabled(be->fd, EVF_READ, cb, param);
if (priv->mevp == NULL) {
WPRINTF(("Could not register event"));
goto error;
}
return (0);
error:
tap_cleanup(be);
return (-1);
}
/*
* Called to send a buffer chain out to the tap device
*/
static ssize_t
tap_send(struct net_backend *be, const struct iovec *iov, int iovcnt)
{
return (writev(be->fd, iov, iovcnt));
}
static ssize_t
tap_peek_recvlen(struct net_backend *be)
{
struct tap_priv *priv = (struct tap_priv *)be->opaque;
ssize_t ret;
if (priv->bbuflen > 0) {
/*
* We already have a packet in the bounce buffer.
* Just return its length.
*/
return priv->bbuflen;
}
/*
* Read the next packet (if any) into the bounce buffer, so
* that we get to know its length and we can return that
* to the caller.
*/
ret = read(be->fd, priv->bbuf, sizeof(priv->bbuf));
if (ret < 0 && errno == EWOULDBLOCK) {
return (0);
}
if (ret > 0)
priv->bbuflen = ret;
return (ret);
}
static ssize_t
tap_recv(struct net_backend *be, const struct iovec *iov, int iovcnt)
{
struct tap_priv *priv = (struct tap_priv *)be->opaque;
ssize_t ret;
if (priv->bbuflen > 0) {
/*
* A packet is available in the bounce buffer, so
* we read it from there.
*/
ret = buf_to_iov(priv->bbuf, priv->bbuflen,
iov, iovcnt, 0);
/* Mark the bounce buffer as empty. */
priv->bbuflen = 0;
return (ret);
}
ret = readv(be->fd, iov, iovcnt);
if (ret < 0 && errno == EWOULDBLOCK) {
return (0);
}
return (ret);
}
static void
tap_recv_enable(struct net_backend *be)
{
struct tap_priv *priv = (struct tap_priv *)be->opaque;
mevent_enable(priv->mevp);
}
static void
tap_recv_disable(struct net_backend *be)
{
struct tap_priv *priv = (struct tap_priv *)be->opaque;
mevent_disable(priv->mevp);
}
static uint64_t
tap_get_cap(struct net_backend *be)
{
return (0); /* no capabilities for now */
}
static int
tap_set_cap(struct net_backend *be, uint64_t features,
unsigned vnet_hdr_len)
{
return ((features || vnet_hdr_len) ? -1 : 0);
}
static struct net_backend tap_backend = {
.prefix = "tap",
.priv_size = sizeof(struct tap_priv),
.init = tap_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,
};
/* A clone of the tap backend, with a different prefix. */
static struct net_backend vmnet_backend = {
.prefix = "vmnet",
.priv_size = sizeof(struct tap_priv),
.init = tap_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, 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,
const char *opts, net_be_rxeof_t cb, void *param)
{
struct tap_priv *p = (struct tap_priv *)be->opaque;
struct ngm_connect ngc;
char *ngopts, *tofree;
char nodename[NG_NODESIZ];
int sbsz;
int ctrl_sock;
int flags;
int path_provided;
int peerhook_provided;
int socket_provided;
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));
strncpy(ngc.ourhook, "vmlink", NG_HOOKSIZ - 1);
tofree = ngopts = strdup(opts);
if (ngopts == NULL) {
WPRINTF(("strdup error"));
return (-1);
}
socket_provided = 0;
path_provided = 0;
peerhook_provided = 0;
while (ngopts != NULL) {
char *value = ngopts;
char *key;
key = strsep(&value, "=");
if (value == NULL)
break;
ngopts = value;
(void) strsep(&ngopts, ",");
if (strcmp(key, "socket") == 0) {
strncpy(nodename, value, NG_NODESIZ - 1);
socket_provided = 1;
} else if (strcmp(key, "path") == 0) {
strncpy(ngc.path, value, NG_PATHSIZ - 1);
path_provided = 1;
} else if (strcmp(key, "hook") == 0) {
strncpy(ngc.ourhook, value, NG_HOOKSIZ - 1);
} else if (strcmp(key, "peerhook") == 0) {
strncpy(ngc.peerhook, value, NG_HOOKSIZ - 1);
peerhook_provided = 1;
}
}
free(tofree);
if (!path_provided) {
WPRINTF(("path must be provided"));
return (-1);
}
if (!peerhook_provided) {
WPRINTF(("peer hook must be provided"));
return (-1);
}
if (NgMkSockNode(socket_provided ? nodename : NULL,
&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,
const char *opts, 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);
/*
* 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 *opts, net_be_rxeof_t cb,
void *param)
{
struct net_backend **pbe, *nbe, *tbe = NULL;
char *devname;
char *options;
int err;
devname = options = strdup(opts);
if (devname == NULL) {
return (-1);
}
devname = strsep(&options, ",");
/*
* 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) {
free(devname);
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, options, cb, param);
if (err) {
free(devname);
free(nbe);
return (err);
}
*ret = nbe;
free(devname);
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);
}
ssize_t
netbe_send(struct net_backend *be, const struct iovec *iov, int iovcnt)
{
return (be->send(be, iov, iovcnt));
}
ssize_t
netbe_peek_recvlen(struct net_backend *be)
{
return (be->peek_recvlen(be));
}
/*
* 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, const struct iovec *iov, int iovcnt)
{
return (be->recv(be, iov, iovcnt));
}
/*
* 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);
}
void
netbe_rx_disable(struct net_backend *be)
{
return be->recv_disable(be);
}
void
netbe_rx_enable(struct net_backend *be)
{
return be->recv_enable(be);
}
size_t
netbe_get_vnet_hdr_len(struct net_backend *be)
{
return (be->be_vnet_hdr_len);
}