448 lines
12 KiB
C
448 lines
12 KiB
C
/*
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* netmap access for qemu
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*
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* Copyright (c) 2012-2013 Luigi Rizzo
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu/osdep.h"
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#include <sys/ioctl.h>
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#include <net/if.h>
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#define NETMAP_WITH_LIBS
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#include <net/netmap.h>
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#include <net/netmap_user.h>
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#include "net/net.h"
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#include "net/tap.h"
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#include "clients.h"
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#include "sysemu/sysemu.h"
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#include "qemu/error-report.h"
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#include "qapi/error.h"
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#include "qemu/iov.h"
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#include "qemu/cutils.h"
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typedef struct NetmapState {
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NetClientState nc;
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struct nm_desc *nmd;
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char ifname[IFNAMSIZ];
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struct netmap_ring *tx;
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struct netmap_ring *rx;
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bool read_poll;
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bool write_poll;
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struct iovec iov[IOV_MAX];
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int vnet_hdr_len; /* Current virtio-net header length. */
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} NetmapState;
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#ifndef __FreeBSD__
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#define pkt_copy bcopy
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#else
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/* A fast copy routine only for multiples of 64 bytes, non overlapped. */
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static inline void
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pkt_copy(const void *_src, void *_dst, int l)
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{
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const uint64_t *src = _src;
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uint64_t *dst = _dst;
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if (unlikely(l >= 1024)) {
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bcopy(src, dst, l);
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return;
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}
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for (; l > 0; l -= 64) {
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*dst++ = *src++;
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*dst++ = *src++;
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*dst++ = *src++;
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*dst++ = *src++;
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*dst++ = *src++;
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*dst++ = *src++;
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*dst++ = *src++;
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*dst++ = *src++;
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}
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}
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#endif /* __FreeBSD__ */
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/*
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* Open a netmap device. We assume there is only one queue
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* (which is the case for the VALE bridge).
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*/
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static struct nm_desc *netmap_open(const NetdevNetmapOptions *nm_opts,
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Error **errp)
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{
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struct nm_desc *nmd;
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struct nmreq req;
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memset(&req, 0, sizeof(req));
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nmd = nm_open(nm_opts->ifname, &req, NETMAP_NO_TX_POLL,
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NULL);
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if (nmd == NULL) {
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error_setg_errno(errp, errno, "Failed to nm_open() %s",
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nm_opts->ifname);
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return NULL;
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}
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return nmd;
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}
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static void netmap_send(void *opaque);
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static void netmap_writable(void *opaque);
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/* Set the event-loop handlers for the netmap backend. */
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static void netmap_update_fd_handler(NetmapState *s)
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{
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qemu_set_fd_handler(s->nmd->fd,
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s->read_poll ? netmap_send : NULL,
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s->write_poll ? netmap_writable : NULL,
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s);
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}
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/* Update the read handler. */
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static void netmap_read_poll(NetmapState *s, bool enable)
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{
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if (s->read_poll != enable) { /* Do nothing if not changed. */
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s->read_poll = enable;
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netmap_update_fd_handler(s);
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}
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}
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/* Update the write handler. */
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static void netmap_write_poll(NetmapState *s, bool enable)
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{
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if (s->write_poll != enable) {
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s->write_poll = enable;
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netmap_update_fd_handler(s);
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}
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}
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static void netmap_poll(NetClientState *nc, bool enable)
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{
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NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
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if (s->read_poll != enable || s->write_poll != enable) {
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s->write_poll = enable;
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s->read_poll = enable;
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netmap_update_fd_handler(s);
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}
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}
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/*
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* The fd_write() callback, invoked if the fd is marked as
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* writable after a poll. Unregister the handler and flush any
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* buffered packets.
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*/
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static void netmap_writable(void *opaque)
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{
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NetmapState *s = opaque;
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netmap_write_poll(s, false);
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qemu_flush_queued_packets(&s->nc);
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}
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static ssize_t netmap_receive(NetClientState *nc,
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const uint8_t *buf, size_t size)
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{
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NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
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struct netmap_ring *ring = s->tx;
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uint32_t i;
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uint32_t idx;
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uint8_t *dst;
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if (unlikely(!ring)) {
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/* Drop. */
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return size;
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}
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if (unlikely(size > ring->nr_buf_size)) {
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RD(5, "[netmap_receive] drop packet of size %d > %d\n",
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(int)size, ring->nr_buf_size);
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return size;
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}
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if (nm_ring_empty(ring)) {
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/* No available slots in the netmap TX ring. */
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netmap_write_poll(s, true);
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return 0;
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}
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i = ring->cur;
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idx = ring->slot[i].buf_idx;
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dst = (uint8_t *)NETMAP_BUF(ring, idx);
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ring->slot[i].len = size;
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ring->slot[i].flags = 0;
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pkt_copy(buf, dst, size);
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ring->cur = ring->head = nm_ring_next(ring, i);
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ioctl(s->nmd->fd, NIOCTXSYNC, NULL);
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return size;
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}
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static ssize_t netmap_receive_iov(NetClientState *nc,
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const struct iovec *iov, int iovcnt)
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{
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NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
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struct netmap_ring *ring = s->tx;
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uint32_t last;
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uint32_t idx;
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uint8_t *dst;
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int j;
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uint32_t i;
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if (unlikely(!ring)) {
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/* Drop the packet. */
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return iov_size(iov, iovcnt);
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}
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last = i = ring->cur;
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if (nm_ring_space(ring) < iovcnt) {
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/* Not enough netmap slots. */
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netmap_write_poll(s, true);
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return 0;
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}
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for (j = 0; j < iovcnt; j++) {
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int iov_frag_size = iov[j].iov_len;
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int offset = 0;
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int nm_frag_size;
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/* Split each iovec fragment over more netmap slots, if
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necessary. */
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while (iov_frag_size) {
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nm_frag_size = MIN(iov_frag_size, ring->nr_buf_size);
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if (unlikely(nm_ring_empty(ring))) {
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/* We run out of netmap slots while splitting the
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iovec fragments. */
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netmap_write_poll(s, true);
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return 0;
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}
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idx = ring->slot[i].buf_idx;
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dst = (uint8_t *)NETMAP_BUF(ring, idx);
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ring->slot[i].len = nm_frag_size;
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ring->slot[i].flags = NS_MOREFRAG;
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pkt_copy(iov[j].iov_base + offset, dst, nm_frag_size);
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last = i;
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i = nm_ring_next(ring, i);
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offset += nm_frag_size;
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iov_frag_size -= nm_frag_size;
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}
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}
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/* The last slot must not have NS_MOREFRAG set. */
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ring->slot[last].flags &= ~NS_MOREFRAG;
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/* Now update ring->cur and ring->head. */
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ring->cur = ring->head = i;
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ioctl(s->nmd->fd, NIOCTXSYNC, NULL);
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return iov_size(iov, iovcnt);
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}
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/* Complete a previous send (backend --> guest) and enable the
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fd_read callback. */
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static void netmap_send_completed(NetClientState *nc, ssize_t len)
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{
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NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
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netmap_read_poll(s, true);
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}
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static void netmap_send(void *opaque)
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{
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NetmapState *s = opaque;
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struct netmap_ring *ring = s->rx;
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/* Keep sending while there are available packets into the netmap
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RX ring and the forwarding path towards the peer is open. */
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while (!nm_ring_empty(ring)) {
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uint32_t i;
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uint32_t idx;
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bool morefrag;
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int iovcnt = 0;
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int iovsize;
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do {
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i = ring->cur;
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idx = ring->slot[i].buf_idx;
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morefrag = (ring->slot[i].flags & NS_MOREFRAG);
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s->iov[iovcnt].iov_base = (u_char *)NETMAP_BUF(ring, idx);
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s->iov[iovcnt].iov_len = ring->slot[i].len;
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iovcnt++;
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ring->cur = ring->head = nm_ring_next(ring, i);
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} while (!nm_ring_empty(ring) && morefrag);
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if (unlikely(nm_ring_empty(ring) && morefrag)) {
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RD(5, "[netmap_send] ran out of slots, with a pending"
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"incomplete packet\n");
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}
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iovsize = qemu_sendv_packet_async(&s->nc, s->iov, iovcnt,
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netmap_send_completed);
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if (iovsize == 0) {
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/* The peer does not receive anymore. Packet is queued, stop
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* reading from the backend until netmap_send_completed()
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*/
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netmap_read_poll(s, false);
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break;
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}
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}
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}
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/* Flush and close. */
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static void netmap_cleanup(NetClientState *nc)
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{
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NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
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qemu_purge_queued_packets(nc);
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netmap_poll(nc, false);
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nm_close(s->nmd);
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s->nmd = NULL;
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}
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/* Offloading manipulation support callbacks. */
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static int netmap_fd_set_vnet_hdr_len(NetmapState *s, int len)
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{
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struct nmreq req;
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/* Issue a NETMAP_BDG_VNET_HDR command to change the virtio-net header
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* length for the netmap adapter associated to 's->ifname'.
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*/
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memset(&req, 0, sizeof(req));
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pstrcpy(req.nr_name, sizeof(req.nr_name), s->ifname);
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req.nr_version = NETMAP_API;
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req.nr_cmd = NETMAP_BDG_VNET_HDR;
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req.nr_arg1 = len;
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return ioctl(s->nmd->fd, NIOCREGIF, &req);
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}
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static bool netmap_has_vnet_hdr_len(NetClientState *nc, int len)
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{
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NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
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int prev_len = s->vnet_hdr_len;
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/* Check that we can set the new length. */
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if (netmap_fd_set_vnet_hdr_len(s, len)) {
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return false;
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}
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/* Restore the previous length. */
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if (netmap_fd_set_vnet_hdr_len(s, prev_len)) {
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error_report("Failed to restore vnet-hdr length %d on %s: %s",
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prev_len, s->ifname, strerror(errno));
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abort();
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}
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return true;
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}
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/* A netmap interface that supports virtio-net headers always
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* supports UFO, so we use this callback also for the has_ufo hook. */
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static bool netmap_has_vnet_hdr(NetClientState *nc)
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{
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return netmap_has_vnet_hdr_len(nc, sizeof(struct virtio_net_hdr));
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}
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static void netmap_using_vnet_hdr(NetClientState *nc, bool enable)
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{
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}
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static void netmap_set_vnet_hdr_len(NetClientState *nc, int len)
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{
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NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
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int err;
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err = netmap_fd_set_vnet_hdr_len(s, len);
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if (err) {
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error_report("Unable to set vnet-hdr length %d on %s: %s",
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len, s->ifname, strerror(errno));
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} else {
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/* Keep track of the current length. */
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s->vnet_hdr_len = len;
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}
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}
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static void netmap_set_offload(NetClientState *nc, int csum, int tso4, int tso6,
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int ecn, int ufo)
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{
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NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
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/* Setting a virtio-net header length greater than zero automatically
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* enables the offloadings. */
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if (!s->vnet_hdr_len) {
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netmap_set_vnet_hdr_len(nc, sizeof(struct virtio_net_hdr));
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}
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}
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/* NetClientInfo methods */
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static NetClientInfo net_netmap_info = {
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.type = NET_CLIENT_DRIVER_NETMAP,
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.size = sizeof(NetmapState),
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.receive = netmap_receive,
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.receive_iov = netmap_receive_iov,
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.poll = netmap_poll,
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.cleanup = netmap_cleanup,
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.has_ufo = netmap_has_vnet_hdr,
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.has_vnet_hdr = netmap_has_vnet_hdr,
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.has_vnet_hdr_len = netmap_has_vnet_hdr_len,
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.using_vnet_hdr = netmap_using_vnet_hdr,
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.set_offload = netmap_set_offload,
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.set_vnet_hdr_len = netmap_set_vnet_hdr_len,
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};
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/* The exported init function
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*
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* ... -net netmap,ifname="..."
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*/
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int net_init_netmap(const Netdev *netdev,
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const char *name, NetClientState *peer, Error **errp)
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{
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const NetdevNetmapOptions *netmap_opts = &netdev->u.netmap;
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struct nm_desc *nmd;
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NetClientState *nc;
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Error *err = NULL;
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NetmapState *s;
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nmd = netmap_open(netmap_opts, &err);
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if (err) {
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error_propagate(errp, err);
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return -1;
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}
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/* Create the object. */
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nc = qemu_new_net_client(&net_netmap_info, peer, "netmap", name);
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s = DO_UPCAST(NetmapState, nc, nc);
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s->nmd = nmd;
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s->tx = NETMAP_TXRING(nmd->nifp, 0);
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s->rx = NETMAP_RXRING(nmd->nifp, 0);
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s->vnet_hdr_len = 0;
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pstrcpy(s->ifname, sizeof(s->ifname), netmap_opts->ifname);
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netmap_read_poll(s, true); /* Initially only poll for reads. */
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return 0;
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}
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