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net: netmap: use nm_open() to open netmap ports 

This patch simplifies the netmap backend code by means of the nm_open()
helper function provided by netmap_user.h, which hides the details of
open(), iotcl() and mmap() carried out on the netmap device.

Moreover, the semantic of nm_open() makes it possible to open special
netmap ports (e.g. pipes, monitors) and use special modes (e.g. host rings
only, single queue mode, exclusive access).

Signed-off-by: Vincenzo Maffione <v.maffione@gmail.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
This commit is contained in:
Vincenzo Maffione 2016-01-25 19:24:35 +01:00 committed by Jason Wang
parent dd793a7488
commit ab685220f6
1 changed files with 32 additions and 65 deletions
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97
net/netmap.c
View File

@ -39,21 +39,12 @@
#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;
struct nm_desc *nmd;
char ifname[IFNAMSIZ];
struct netmap_ring *tx;
struct netmap_ring *rx;
bool read_poll;
bool write_poll;
struct iovec iov[IOV_MAX];
@ -90,44 +81,23 @@ pkt_copy(const void *_src, void *_dst, int l)
* Open a netmap device. We assume there is only one queue
* (which is the case for the VALE bridge).
*/
static void netmap_open(NetmapPriv *me, Error **errp)
static struct nm_desc *netmap_open(const NetdevNetmapOptions *nm_opts,
Error **errp)
{
int fd;
int err;
size_t l;
struct nm_desc *nmd;
struct nmreq req;
me->fd = fd = open(me->fdname, O_RDWR);
if (fd < 0) {
error_setg_file_open(errp, errno, me->fdname);
return;
}
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_setg_errno(errp, errno, "Unable to register %s", me->ifname);
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_setg_errno(errp, errno, "Unable to mmap netmap shared memory");
me->mem = NULL;
goto error;
nmd = nm_open(nm_opts->ifname, &req, NETMAP_NO_TX_POLL,
NULL);
if (nmd == NULL) {
error_setg_errno(errp, errno, "Failed to nm_open() %s",
nm_opts->ifname);
return NULL;
}
me->nifp = NETMAP_IF(me->mem, req.nr_offset);
me->tx = NETMAP_TXRING(me->nifp, 0);
me->rx = NETMAP_RXRING(me->nifp, 0);
return;
error:
close(me->fd);
return nmd;
}
static void netmap_send(void *opaque);
@ -136,7 +106,7 @@ 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_handler(s->me.fd,
qemu_set_fd_handler(s->nmd->fd,
s->read_poll ? netmap_send : NULL,
s->write_poll ? netmap_writable : NULL,
s);
@ -188,7 +158,7 @@ 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;
struct netmap_ring *ring = s->tx;
uint32_t i;
uint32_t idx;
uint8_t *dst;
@ -218,7 +188,7 @@ static ssize_t netmap_receive(NetClientState *nc,
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);
ioctl(s->nmd->fd, NIOCTXSYNC, NULL);
return size;
}
@ -227,7 +197,7 @@ 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;
struct netmap_ring *ring = s->tx;
uint32_t last;
uint32_t idx;
uint8_t *dst;
@ -284,7 +254,7 @@ static ssize_t netmap_receive_iov(NetClientState *nc,
/* Now update ring->cur and ring->head. */
ring->cur = ring->head = i;
ioctl(s->me.fd, NIOCTXSYNC, NULL);
ioctl(s->nmd->fd, NIOCTXSYNC, NULL);
return iov_size(iov, iovcnt);
}
@ -301,7 +271,7 @@ static void netmap_send_completed(NetClientState *nc, ssize_t len)
static void netmap_send(void *opaque)
{
NetmapState *s = opaque;
struct netmap_ring *ring = s->me.rx;
struct netmap_ring *ring = s->rx;
/* Keep sending while there are available packets into the netmap
RX ring and the forwarding path towards the peer is open. */
@ -349,10 +319,8 @@ static void netmap_cleanup(NetClientState *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;
nm_close(s->nmd);
s->nmd = NULL;
}
/* Offloading manipulation support callbacks. */
@ -383,17 +351,17 @@ static void netmap_set_vnet_hdr_len(NetClientState *nc, int len)
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'.
* length for the netmap adapter associated to 's->ifname'.
*/
memset(&req, 0, sizeof(req));
pstrcpy(req.nr_name, sizeof(req.nr_name), s->me.ifname);
pstrcpy(req.nr_name, sizeof(req.nr_name), s->ifname);
req.nr_version = NETMAP_API;
req.nr_cmd = NETMAP_BDG_VNET_HDR;
req.nr_arg1 = len;
err = ioctl(s->me.fd, NIOCREGIF, &req);
err = ioctl(s->nmd->fd, NIOCREGIF, &req);
if (err) {
error_report("Unable to execute NETMAP_BDG_VNET_HDR on %s: %s",
s->me.ifname, strerror(errno));
s->ifname, strerror(errno));
} else {
/* Keep track of the current length. */
s->vnet_hdr_len = len;
@ -437,16 +405,12 @@ int net_init_netmap(const NetClientOptions *opts,
const char *name, NetClientState *peer, Error **errp)
{
const NetdevNetmapOptions *netmap_opts = opts->u.netmap;
struct nm_desc *nmd;
NetClientState *nc;
Error *err = NULL;
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);
netmap_open(&me, &err);
nmd = netmap_open(netmap_opts, &err);
if (err) {
error_propagate(errp, err);
return -1;
@ -454,8 +418,11 @@ int net_init_netmap(const NetClientOptions *opts,
/* Create the object. */
nc = qemu_new_net_client(&net_netmap_info, peer, "netmap", name);
s = DO_UPCAST(NetmapState, nc, nc);
s->me = me;
s->nmd = nmd;
s->tx = NETMAP_TXRING(nmd->nifp, 0);
s->rx = NETMAP_RXRING(nmd->nifp, 0);
s->vnet_hdr_len = 0;
pstrcpy(s->ifname, sizeof(s->ifname), netmap_opts->ifname);
netmap_read_poll(s, true); /* Initially only poll for reads. */
return 0;