/*
* netmap access for qemu
*
* Copyright (c) 2012-2013 Luigi Rizzo
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include <sys/ioctl.h>
#include <net/if.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 "qemu/error-report.h"
#include "qapi/error.h"
#include "qemu/iov.h"
#include "qemu/cutils.h"
#include "qemu/main-loop.h"
typedef struct NetmapState {
NetClientState nc;
struct nm_desc *nmd;
char ifname[IFNAMSIZ];
struct netmap_ring *tx;
struct netmap_ring *rx;
bool read_poll;
bool write_poll;
struct iovec iov[IOV_MAX];
int vnet_hdr_len; /* Current virtio-net header length. */
} NetmapState;
#ifndef __FreeBSD__
#define pkt_copy bcopy
#else
/* A fast copy routine only for multiples of 64 bytes, non overlapped. */
static inline void
pkt_copy(const void *_src, void *_dst, int l)
{
const uint64_t *src = _src;
uint64_t *dst = _dst;
if (unlikely(l >= 1024)) {
bcopy(src, dst, l);
return;
}
for (; l > 0; l -= 64) {
*dst++ = *src++;
*dst++ = *src++;
*dst++ = *src++;
*dst++ = *src++;
*dst++ = *src++;
*dst++ = *src++;
*dst++ = *src++;
*dst++ = *src++;
}
}
#endif /* __FreeBSD__ */
/*
* Open a netmap device. We assume there is only one queue
* (which is the case for the VALE bridge).
*/
static struct nm_desc *netmap_open(const NetdevNetmapOptions *nm_opts,
Error **errp)
{
struct nm_desc *nmd;
struct nmreq req;
memset(&req, 0, sizeof(req));
nmd = nm_open(nm_opts->ifname, &req, NETMAP_NO_TX_POLL,
NULL);
if (nmd == NULL) {
error_setg_errno(errp, errno, "Failed to nm_open() %s",
nm_opts->ifname);
return NULL;
}
return nmd;
}
static void netmap_send(void *opaque);
static void netmap_writable(void *opaque);
/* Set the event-loop handlers for the netmap backend. */
static void netmap_update_fd_handler(NetmapState *s)
{
qemu_set_fd_handler(s->nmd->fd,
s->read_poll ? netmap_send : NULL,
s->write_poll ? netmap_writable : NULL,
s);
}
/* Update the read handler. */
static void netmap_read_poll(NetmapState *s, bool enable)
{
if (s->read_poll != enable) { /* Do nothing if not changed. */
s->read_poll = enable;
netmap_update_fd_handler(s);
}
}
/* Update the write handler. */
static void netmap_write_poll(NetmapState *s, bool enable)
{
if (s->write_poll != enable) {
s->write_poll = enable;
netmap_update_fd_handler(s);
}
}
static void netmap_poll(NetClientState *nc, bool enable)
{
NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
if (s->read_poll != enable || s->write_poll != enable) {
s->write_poll = enable;
s->read_poll = enable;
netmap_update_fd_handler(s);
}
}
/*
* The fd_write() callback, invoked if the fd is marked as
* writable after a poll. Unregister the handler and flush any
* buffered packets.
*/
static void netmap_writable(void *opaque)
{
NetmapState *s = opaque;
netmap_write_poll(s, false);
qemu_flush_queued_packets(&s->nc);
}
static ssize_t netmap_receive_iov(NetClientState *nc,
const struct iovec *iov, int iovcnt)
{
NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
struct netmap_ring *ring = s->tx;
unsigned int tail = ring->tail;
ssize_t totlen = 0;
uint32_t last;
uint32_t idx;
uint8_t *dst;
int j;
uint32_t i;
last = i = ring->head;
if (nm_ring_space(ring) < iovcnt) {
/* Not enough netmap slots. Tell the kernel that we have seen the new
* available slots (so that it notifies us again when it has more
* ones), but without publishing any new slots to be processed
* (e.g., we don't advance ring->head). */
ring->cur = tail;
netmap_write_poll(s, true);
return 0;
}
for (j = 0; j < iovcnt; j++) {
int iov_frag_size = iov[j].iov_len;
int offset = 0;
int nm_frag_size;
totlen += iov_frag_size;
/* Split each iovec fragment over more netmap slots, if
necessary. */
while (iov_frag_size) {
nm_frag_size = MIN(iov_frag_size, ring->nr_buf_size);
if (unlikely(i == tail)) {
/* We ran out of netmap slots while splitting the
iovec fragments. */
ring->cur = tail;
netmap_write_poll(s, true);
return 0;
}
idx = ring->slot[i].buf_idx;
dst = (uint8_t *)NETMAP_BUF(ring, idx);
ring->slot[i].len = nm_frag_size;
ring->slot[i].flags = NS_MOREFRAG;
pkt_copy(iov[j].iov_base + offset, dst, nm_frag_size);
last = i;
i = nm_ring_next(ring, i);
offset += nm_frag_size;
iov_frag_size -= nm_frag_size;
}
}
/* The last slot must not have NS_MOREFRAG set. */
ring->slot[last].flags &= ~NS_MOREFRAG;
/* Now update ring->head and ring->cur to publish the new slots and
* the new wakeup point. */
ring->head = ring->cur = i;
ioctl(s->nmd->fd, NIOCTXSYNC, NULL);
return totlen;
}
static ssize_t netmap_receive(NetClientState *nc,
const uint8_t *buf, size_t size)
{
struct iovec iov;
iov.iov_base = (void *)buf;
iov.iov_len = size;
return netmap_receive_iov(nc, &iov, 1);
}
/* Complete a previous send (backend --> guest) and enable the
fd_read callback. */
static void netmap_send_completed(NetClientState *nc, ssize_t len)
{
NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
netmap_read_poll(s, true);
}
static void netmap_send(void *opaque)
{
NetmapState *s = opaque;
struct netmap_ring *ring = s->rx;
unsigned int tail = ring->tail;
/* Keep sending while there are available slots in the netmap
RX ring and the forwarding path towards the peer is open. */
while (ring->head != tail) {
uint32_t i = ring->head;
uint32_t idx;
bool morefrag;
int iovcnt = 0;
int iovsize;
/* Get a (possibly multi-slot) packet. */
do {
idx = ring->slot[i].buf_idx;
morefrag = (ring->slot[i].flags & NS_MOREFRAG);
s->iov[iovcnt].iov_base = (void *)NETMAP_BUF(ring, idx);
s->iov[iovcnt].iov_len = ring->slot[i].len;
iovcnt++;
i = nm_ring_next(ring, i);
} while (i != tail && morefrag);
/* Advance ring->cur to tell the kernel that we have seen the slots. */
ring->cur = i;
if (unlikely(morefrag)) {
/* This is a truncated packet, so we can stop without releasing the
* incomplete slots by updating ring->head. We will hopefully
* re-read the complete packet the next time we are called. */
break;
}
iovsize = qemu_sendv_packet_async(&s->nc, s->iov, iovcnt,
netmap_send_completed);
/* Release the slots to the kernel. */
ring->head = i;
if (iovsize == 0) {
/* The peer does not receive anymore. Packet is queued, stop
* reading from the backend until netmap_send_completed(). */
netmap_read_poll(s, false);
break;
}
}
}
/* Flush and close. */
static void netmap_cleanup(NetClientState *nc)
{
NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
qemu_purge_queued_packets(nc);
netmap_poll(nc, false);
nm_close(s->nmd);
s->nmd = NULL;
}
/* Offloading manipulation support callbacks. */
static int netmap_fd_set_vnet_hdr_len(NetmapState *s, int len)
{
struct nmreq req;
/* Issue a NETMAP_BDG_VNET_HDR command to change the virtio-net header
* length for the netmap adapter associated to 's->ifname'.
*/
memset(&req, 0, sizeof(req));
pstrcpy(req.nr_name, sizeof(req.nr_name), s->ifname);
req.nr_version = NETMAP_API;
req.nr_cmd = NETMAP_BDG_VNET_HDR;
req.nr_arg1 = len;
return ioctl(s->nmd->fd, NIOCREGIF, &req);
}
static bool netmap_has_vnet_hdr_len(NetClientState *nc, int len)
{
NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
int prev_len = s->vnet_hdr_len;
/* Check that we can set the new length. */
if (netmap_fd_set_vnet_hdr_len(s, len)) {
return false;
}
/* Restore the previous length. */
if (netmap_fd_set_vnet_hdr_len(s, prev_len)) {
error_report("Failed to restore vnet-hdr length %d on %s: %s",
prev_len, s->ifname, strerror(errno));
abort();
}
return true;
}
/* A netmap interface that supports virtio-net headers always
* supports UFO, so we use this callback also for the has_ufo hook. */
static bool netmap_has_vnet_hdr(NetClientState *nc)
{
return netmap_has_vnet_hdr_len(nc, sizeof(struct virtio_net_hdr));
}
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;
err = netmap_fd_set_vnet_hdr_len(s, len);
if (err) {
error_report("Unable to set vnet-hdr length %d on %s: %s",
len, s->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 = {
.type = NET_CLIENT_DRIVER_NETMAP,
.size = sizeof(NetmapState),
.receive = netmap_receive,
.receive_iov = netmap_receive_iov,
.poll = netmap_poll,
.cleanup = netmap_cleanup,
.has_ufo = netmap_has_vnet_hdr,
.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
*
* ... -net netmap,ifname="..."
*/
int net_init_netmap(const Netdev *netdev,
const char *name, NetClientState *peer, Error **errp)
{
const NetdevNetmapOptions *netmap_opts = &netdev->u.netmap;
struct nm_desc *nmd;
NetClientState *nc;
Error *err = NULL;
NetmapState *s;
nmd = netmap_open(netmap_opts, &err);
if (err) {
error_propagate(errp, err);
return -1;
}
/* Create the object. */
nc = qemu_new_net_client(&net_netmap_info, peer, "netmap", name);
s = DO_UPCAST(NetmapState, nc, nc);
s->nmd = nmd;
s->tx = NETMAP_TXRING(nmd->nifp, 0);
s->rx = NETMAP_RXRING(nmd->nifp, 0);
s->vnet_hdr_len = 0;
pstrcpy(s->ifname, sizeof(s->ifname), netmap_opts->ifname);
netmap_read_poll(s, true); /* Initially only poll for reads. */
return 0;
}
