diff options
Diffstat (limited to 'net/netmap.c')
| -rw-r--r-- | net/netmap.c | 435 |
1 files changed, 435 insertions, 0 deletions
diff --git a/net/netmap.c b/net/netmap.c new file mode 100644 index 0000000000..0ccc4976b5 --- /dev/null +++ b/net/netmap.c @@ -0,0 +1,435 @@ +/* + * 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; +} + |