qemu/net/netmap.c
Vincenzo Maffione 0a985b3727 net: Disable netmap backend when not supported
This patch fixes configure so that the netmap backend is not compiled in if the
host doesn't support an API version >= 11. A version upper bound (15) has been
added so that the netmap API can be extended with some minor features without
requiring QEMU code modifications.

Moreover, some changes have been done to net/netmap.c in order to reflect the
current netmap API/ABI (11).

The NETMAP_WITH_LIBS macro makes possible to include some utilities (e.g.
netmap ring macros, D(), RD() and other high level functions) through the netmap
headers. In this way we get rid of the D and RD macro definitions in the QEMU
code, and we open the way for further code simplifications that will be
introduced by future patches.

Signed-off-by: Vincenzo Maffione <v.maffione@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-02-25 11:50:17 +01:00

473 lines
13 KiB
C

/*
* 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 <sys/ioctl.h>
#include <net/if.h>
#include <sys/mman.h>
#include <stdint.h>
#include <stdio.h>
#define NETMAP_WITH_LIBS
#include <net/netmap.h>
#include <net/netmap_user.h>
#include "net/net.h"
#include "net/tap.h"
#include "clients.h"
#include "sysemu/sysemu.h"
#include "qemu/error-report.h"
#include "qemu/iov.h"
/* Private netmap device info. */
typedef struct NetmapPriv {
int fd;
size_t memsize;
void *mem;
struct netmap_if *nifp;
struct netmap_ring *rx;
struct netmap_ring *tx;
char fdname[PATH_MAX]; /* Normally "/dev/netmap". */
char ifname[IFNAMSIZ];
} NetmapPriv;
typedef struct NetmapState {
NetClientState nc;
NetmapPriv me;
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 int netmap_open(NetmapPriv *me)
{
int fd;
int err;
size_t l;
struct nmreq req;
me->fd = fd = open(me->fdname, O_RDWR);
if (fd < 0) {
error_report("Unable to open netmap device '%s' (%s)",
me->fdname, strerror(errno));
return -1;
}
memset(&req, 0, sizeof(req));
pstrcpy(req.nr_name, sizeof(req.nr_name), me->ifname);
req.nr_ringid = NETMAP_NO_TX_POLL;
req.nr_version = NETMAP_API;
err = ioctl(fd, NIOCREGIF, &req);
if (err) {
error_report("Unable to register %s: %s", me->ifname, strerror(errno));
goto error;
}
l = me->memsize = req.nr_memsize;
me->mem = mmap(0, l, PROT_WRITE | PROT_READ, MAP_SHARED, fd, 0);
if (me->mem == MAP_FAILED) {
error_report("Unable to mmap netmap shared memory: %s",
strerror(errno));
me->mem = NULL;
goto error;
}
me->nifp = NETMAP_IF(me->mem, req.nr_offset);
me->tx = NETMAP_TXRING(me->nifp, 0);
me->rx = NETMAP_RXRING(me->nifp, 0);
return 0;
error:
close(me->fd);
return -1;
}
/* Tell the event-loop if the netmap backend can send packets
to the frontend. */
static int netmap_can_send(void *opaque)
{
NetmapState *s = opaque;
return qemu_can_send_packet(&s->nc);
}
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_handler2(s->me.fd,
s->read_poll ? netmap_can_send : NULL,
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->read_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(NetClientState *nc,
const uint8_t *buf, size_t size)
{
NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
struct netmap_ring *ring = s->me.tx;
uint32_t i;
uint32_t idx;
uint8_t *dst;
if (unlikely(!ring)) {
/* Drop. */
return size;
}
if (unlikely(size > ring->nr_buf_size)) {
RD(5, "[netmap_receive] drop packet of size %d > %d\n",
(int)size, ring->nr_buf_size);
return size;
}
if (nm_ring_empty(ring)) {
/* No available slots in the netmap TX ring. */
netmap_write_poll(s, true);
return 0;
}
i = ring->cur;
idx = ring->slot[i].buf_idx;
dst = (uint8_t *)NETMAP_BUF(ring, idx);
ring->slot[i].len = size;
ring->slot[i].flags = 0;
pkt_copy(buf, dst, size);
ring->cur = ring->head = nm_ring_next(ring, i);
ioctl(s->me.fd, NIOCTXSYNC, NULL);
return size;
}
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->me.tx;
uint32_t last;
uint32_t idx;
uint8_t *dst;
int j;
uint32_t i;
if (unlikely(!ring)) {
/* Drop the packet. */
return iov_size(iov, iovcnt);
}
last = i = ring->cur;
if (nm_ring_space(ring) < iovcnt) {
/* Not enough netmap slots. */
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;
/* 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(nm_ring_empty(ring))) {
/* We run out of netmap slots while splitting the
iovec fragments. */
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->cur and ring->head. */
ring->cur = ring->head = i;
ioctl(s->me.fd, NIOCTXSYNC, NULL);
return iov_size(iov, iovcnt);
}
/* 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->me.rx;
/* Keep sending while there are available packets into the netmap
RX ring and the forwarding path towards the peer is open. */
while (!nm_ring_empty(ring) && qemu_can_send_packet(&s->nc)) {
uint32_t i;
uint32_t idx;
bool morefrag;
int iovcnt = 0;
int iovsize;
do {
i = ring->cur;
idx = ring->slot[i].buf_idx;
morefrag = (ring->slot[i].flags & NS_MOREFRAG);
s->iov[iovcnt].iov_base = (u_char *)NETMAP_BUF(ring, idx);
s->iov[iovcnt].iov_len = ring->slot[i].len;
iovcnt++;
ring->cur = ring->head = nm_ring_next(ring, i);
} while (!nm_ring_empty(ring) && morefrag);
if (unlikely(nm_ring_empty(ring) && morefrag)) {
RD(5, "[netmap_send] ran out of slots, with a pending"
"incomplete packet\n");
}
iovsize = qemu_sendv_packet_async(&s->nc, s->iov, iovcnt,
netmap_send_completed);
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);
munmap(s->me.mem, s->me.memsize);
close(s->me.fd);
s->me.fd = -1;
}
/* Offloading manipulation support callbacks. */
static bool netmap_has_ufo(NetClientState *nc)
{
return true;
}
static bool netmap_has_vnet_hdr(NetClientState *nc)
{
return true;
}
static bool netmap_has_vnet_hdr_len(NetClientState *nc, int len)
{
return len == 0 || len == sizeof(struct virtio_net_hdr) ||
len == sizeof(struct virtio_net_hdr_mrg_rxbuf);
}
static void netmap_using_vnet_hdr(NetClientState *nc, bool enable)
{
}
static void netmap_set_vnet_hdr_len(NetClientState *nc, int len)
{
NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
int err;
struct nmreq req;
/* Issue a NETMAP_BDG_VNET_HDR command to change the virtio-net header
* length for the netmap adapter associated to 'me->ifname'.
*/
memset(&req, 0, sizeof(req));
pstrcpy(req.nr_name, sizeof(req.nr_name), s->me.ifname);
req.nr_version = NETMAP_API;
req.nr_cmd = NETMAP_BDG_VNET_HDR;
req.nr_arg1 = len;
err = ioctl(s->me.fd, NIOCREGIF, &req);
if (err) {
error_report("Unable to execute NETMAP_BDG_VNET_HDR on %s: %s",
s->me.ifname, strerror(errno));
} else {
/* Keep track of the current length. */
s->vnet_hdr_len = len;
}
}
static void netmap_set_offload(NetClientState *nc, int csum, int tso4, int tso6,
int ecn, int ufo)
{
NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
/* Setting a virtio-net header length greater than zero automatically
* enables the offloadings.
*/
if (!s->vnet_hdr_len) {
netmap_set_vnet_hdr_len(nc, sizeof(struct virtio_net_hdr));
}
}
/* NetClientInfo methods */
static NetClientInfo net_netmap_info = {
.type = NET_CLIENT_OPTIONS_KIND_NETMAP,
.size = sizeof(NetmapState),
.receive = netmap_receive,
.receive_iov = netmap_receive_iov,
.poll = netmap_poll,
.cleanup = netmap_cleanup,
.has_ufo = netmap_has_ufo,
.has_vnet_hdr = netmap_has_vnet_hdr,
.has_vnet_hdr_len = netmap_has_vnet_hdr_len,
.using_vnet_hdr = netmap_using_vnet_hdr,
.set_offload = netmap_set_offload,
.set_vnet_hdr_len = netmap_set_vnet_hdr_len,
};
/* The exported init function
*
* ... -net netmap,ifname="..."
*/
int net_init_netmap(const NetClientOptions *opts,
const char *name, NetClientState *peer)
{
const NetdevNetmapOptions *netmap_opts = opts->netmap;
NetClientState *nc;
NetmapPriv me;
NetmapState *s;
pstrcpy(me.fdname, sizeof(me.fdname),
netmap_opts->has_devname ? netmap_opts->devname : "/dev/netmap");
/* Set default name for the port if not supplied. */
pstrcpy(me.ifname, sizeof(me.ifname), netmap_opts->ifname);
if (netmap_open(&me)) {
return -1;
}
/* Create the object. */
nc = qemu_new_net_client(&net_netmap_info, peer, "netmap", name);
s = DO_UPCAST(NetmapState, nc, nc);
s->me = me;
s->vnet_hdr_len = 0;
netmap_read_poll(s, true); /* Initially only poll for reads. */
return 0;
}