--- /dev/null
+/*
+ * 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;
+}
+
projects / mirror_qemu.git / commitdiff