/*
* 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 <net/netmap.h>
#include <net/netmap_user.h>
#include "net/net.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];
} NetmapState;
#define D(format, ...) \
do { \
struct timeval __xxts; \
gettimeofday(&__xxts, NULL); \
printf("%03d.%06d %s [%d] " format "\n", \
(int)__xxts.tv_sec % 1000, (int)__xxts.tv_usec, \
__func__, __LINE__, ##__VA_ARGS__); \
} while (0)
/* Rate limited version of "D", lps indicates how many per second */
#define RD(lps, format, ...) \
do { \
static int t0, __cnt; \
struct timeval __xxts; \
gettimeofday(&__xxts, NULL); \
if (t0 != __xxts.tv_sec) { \
t0 = __xxts.tv_sec; \
__cnt = 0; \
} \
if (__cnt++ < lps) { \
D(format, ##__VA_ARGS__); \
} \
} while (0)
#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 (ring->avail == 0) {
/* 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 = NETMAP_RING_NEXT(ring, i);
ring->avail--;
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;
uint32_t avail;
if (unlikely(!ring)) {
/* Drop the packet. */
return iov_size(iov, iovcnt);
}
i = ring->cur;
avail = ring->avail;
if (avail < 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(avail == 0)) {
/* 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 = NETMAP_RING_NEXT(ring, i);
avail--;
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->avail. */
ring->cur = i;
ring->avail = avail;
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 (ring->avail > 0 && 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 = NETMAP_RING_NEXT(ring, i);
ring->avail--;
} while (ring->avail && morefrag);
if (unlikely(!ring->avail && 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;
}
/* 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,
};
/* 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;
netmap_read_poll(s, true); /* Initially only poll for reads. */
return 0;
}
