DPDK  17.02.1
examples/netmap_compat/lib/compat_netmap.c
/*-
* BSD LICENSE
*
* Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <errno.h>
#include <inttypes.h>
#include <poll.h>
#include <stdio.h>
#include <stdlib.h>
#include <net/if.h>
#include <sys/types.h>
#include <sys/resource.h>
#include <sys/mman.h>
#include <rte_common.h>
#include <rte_errno.h>
#include <rte_ethdev.h>
#include <rte_log.h>
#include <rte_malloc.h>
#include <rte_mbuf.h>
#include <rte_memzone.h>
#include <rte_spinlock.h>
#include <rte_string_fns.h>
#include "compat_netmap.h"
struct netmap_port {
struct rte_mempool *pool;
struct netmap_if *nmif;
struct rte_eth_conf eth_conf;
struct rte_eth_txconf tx_conf;
struct rte_eth_rxconf rx_conf;
int32_t socket_id;
uint16_t nr_tx_rings;
uint16_t nr_rx_rings;
uint32_t nr_tx_slots;
uint32_t nr_rx_slots;
uint16_t tx_burst;
uint16_t rx_burst;
uint32_t fd;
};
struct fd_port {
uint32_t port;
};
#ifndef POLLRDNORM
#define POLLRDNORM 0x0040
#endif
#ifndef POLLWRNORM
#define POLLWRNORM 0x0100
#endif
#define FD_PORT_FREE UINT32_MAX
#define FD_PORT_RSRV (FD_PORT_FREE - 1)
struct netmap_state {
struct rte_netmap_conf conf;
uintptr_t buf_start;
void *mem;
uint32_t mem_sz;
uint32_t netif_memsz;
};
#define COMPAT_NETMAP_MAX_NOFILE (2 * RTE_MAX_ETHPORTS)
#define COMPAT_NETMAP_MAX_BURST 64
#define COMPAT_NETMAP_MAX_PKT_PER_SYNC (2 * COMPAT_NETMAP_MAX_BURST)
static struct netmap_port ports[RTE_MAX_ETHPORTS];
static struct netmap_state netmap;
static struct fd_port fd_port[COMPAT_NETMAP_MAX_NOFILE];
static const int next_fd_start = RLIMIT_NOFILE + 1;
static rte_spinlock_t netmap_lock;
#define IDX_TO_FD(x) ((x) + next_fd_start)
#define FD_TO_IDX(x) ((x) - next_fd_start)
#define FD_VALID(x) ((x) >= next_fd_start && \
(x) < (typeof (x))(RTE_DIM(fd_port) + next_fd_start))
#define PORT_NUM_RINGS (2 * netmap.conf.max_rings)
#define PORT_NUM_SLOTS (PORT_NUM_RINGS * netmap.conf.max_slots)
#define BUF_IDX(port, ring, slot) \
(((port) * PORT_NUM_RINGS + (ring)) * netmap.conf.max_slots + \
(slot))
#define NETMAP_IF_RING_OFS(rid, rings, slots) ({\
struct netmap_if *_if; \
struct netmap_ring *_rg; \
sizeof(*_if) + \
(rings) * sizeof(_if->ring_ofs[0]) + \
(rid) * sizeof(*_rg) + \
(slots) * sizeof(_rg->slot[0]); \
})
static void netmap_unregif(uint32_t idx, uint32_t port);
static int32_t
ifname_to_portid(const char *ifname, uint8_t *port)
{
char *endptr;
uint64_t portid;
errno = 0;
portid = strtoul(ifname, &endptr, 10);
if (endptr == ifname || *endptr != '\0' ||
portid >= RTE_DIM(ports) || errno != 0)
return -EINVAL;
*port = (uint8_t)portid;
return 0;
}
static void
mbuf_to_slot(struct rte_mbuf *mbuf, struct netmap_ring *r, uint32_t index)
{
char *data;
uint16_t length;
data = rte_pktmbuf_mtod(mbuf, char *);
length = rte_pktmbuf_data_len(mbuf);
if (length > r->nr_buf_size)
length = 0;
r->slot[index].len = length;
rte_memcpy(NETMAP_BUF(r, r->slot[index].buf_idx), data, length);
}
static void
slot_to_mbuf(struct netmap_ring *r, uint32_t index, struct rte_mbuf *mbuf)
{
char *data;
uint16_t length;
length = r->slot[index].len;
data = rte_pktmbuf_append(mbuf, length);
if (data != NULL)
rte_memcpy(data, NETMAP_BUF(r, r->slot[index].buf_idx), length);
}
static int32_t
fd_reserve(void)
{
uint32_t i;
for (i = 0; i != RTE_DIM(fd_port) && fd_port[i].port != FD_PORT_FREE;
i++)
;
if (i == RTE_DIM(fd_port))
return -ENOMEM;
fd_port[i].port = FD_PORT_RSRV;
return IDX_TO_FD(i);
}
static int32_t
fd_release(int32_t fd)
{
uint32_t idx, port;
idx = FD_TO_IDX(fd);
if (!FD_VALID(fd) || (port = fd_port[idx].port) == FD_PORT_FREE)
return -EINVAL;
/* if we still have a valid port attached, release the port */
if (port < RTE_DIM(ports) && ports[port].fd == idx) {
netmap_unregif(idx, port);
}
fd_port[idx].port = FD_PORT_FREE;
return 0;
}
static int
check_nmreq(struct nmreq *req, uint8_t *port)
{
int32_t rc;
uint8_t portid;
if (req == NULL)
return -EINVAL;
if (req->nr_version != NETMAP_API) {
req->nr_version = NETMAP_API;
return -EINVAL;
}
if ((rc = ifname_to_portid(req->nr_name, &portid)) != 0) {
RTE_LOG(ERR, USER1, "Invalid interface name:\"%s\" "
"in NIOCGINFO call\n", req->nr_name);
return rc;
}
if (ports[portid].pool == NULL) {
RTE_LOG(ERR, USER1, "Misconfigured portid %hhu\n", portid);
return -EINVAL;
}
*port = portid;
return 0;
}
static int
ioctl_niocginfo(__rte_unused int fd, void * param)
{
uint8_t portid;
struct nmreq *req;
int32_t rc;
req = (struct nmreq *)param;
if ((rc = check_nmreq(req, &portid)) != 0)
return rc;
req->nr_tx_rings = (uint16_t)(ports[portid].nr_tx_rings - 1);
req->nr_rx_rings = (uint16_t)(ports[portid].nr_rx_rings - 1);
req->nr_tx_slots = ports[portid].nr_tx_slots;
req->nr_rx_slots = ports[portid].nr_rx_slots;
/* in current implementation we have all NETIFs shared aone region. */
req->nr_memsize = netmap.mem_sz;
req->nr_offset = 0;
return 0;
}
static void
netmap_ring_setup(struct netmap_ring *ring, uint8_t port, uint32_t ringid,
uint32_t num_slots)
{
uint32_t j;
ring->buf_ofs = netmap.buf_start - (uintptr_t)ring;
ring->num_slots = num_slots;
ring->cur = 0;
ring->reserved = 0;
ring->nr_buf_size = netmap.conf.max_bufsz;
ring->flags = 0;
ring->ts.tv_sec = 0;
ring->ts.tv_usec = 0;
for (j = 0; j < ring->num_slots; j++) {
ring->slot[j].buf_idx = BUF_IDX(port, ringid, j);
ring->slot[j].len = 0;
ring->flags = 0;
}
}
static int
netmap_regif(struct nmreq *req, uint32_t idx, uint8_t port)
{
struct netmap_if *nmif;
struct netmap_ring *ring;
uint32_t i, slots, start_ring;
int32_t rc;
if (ports[port].fd < RTE_DIM(fd_port)) {
RTE_LOG(ERR, USER1, "port %hhu already in use by fd: %u\n",
port, IDX_TO_FD(ports[port].fd));
return -EBUSY;
}
if (fd_port[idx].port != FD_PORT_RSRV) {
RTE_LOG(ERR, USER1, "fd: %u is misconfigured\n",
IDX_TO_FD(idx));
return -EBUSY;
}
nmif = ports[port].nmif;
/* setup netmap_if fields. */
memset(nmif, 0, netmap.netif_memsz);
/* only ALL rings supported right now. */
if (req->nr_ringid != 0)
return -EINVAL;
snprintf(nmif->ni_name, sizeof(nmif->ni_name), "%s", req->nr_name);
nmif->ni_version = req->nr_version;
/* Netmap uses ni_(r|t)x_rings + 1 */
nmif->ni_rx_rings = ports[port].nr_rx_rings - 1;
nmif->ni_tx_rings = ports[port].nr_tx_rings - 1;
/*
* Setup TX rings and slots.
* Refer to the comments in netmap.h for details
*/
slots = 0;
for (i = 0; i < nmif->ni_tx_rings + 1; i++) {
nmif->ring_ofs[i] = NETMAP_IF_RING_OFS(i,
PORT_NUM_RINGS, slots);
ring = NETMAP_TXRING(nmif, i);
netmap_ring_setup(ring, port, i, ports[port].nr_tx_slots);
ring->avail = ring->num_slots;
slots += ports[port].nr_tx_slots;
}
/*
* Setup RX rings and slots.
* Refer to the comments in netmap.h for details
*/
start_ring = i;
for (; i < nmif->ni_rx_rings + 1 + start_ring; i++) {
nmif->ring_ofs[i] = NETMAP_IF_RING_OFS(i,
PORT_NUM_RINGS, slots);
ring = NETMAP_RXRING(nmif, (i - start_ring));
netmap_ring_setup(ring, port, i, ports[port].nr_rx_slots);
ring->avail = 0;
slots += ports[port].nr_rx_slots;
}
if ((rc = rte_eth_dev_start(port)) < 0) {
RTE_LOG(ERR, USER1,
"Couldn't start ethernet device %s (error %d)\n",
req->nr_name, rc);
return rc;
}
/* setup fdi <--> port relationtip. */
ports[port].fd = idx;
fd_port[idx].port = port;
req->nr_memsize = netmap.mem_sz;
req->nr_offset = (uintptr_t)nmif - (uintptr_t)netmap.mem;
return 0;
}
static int
ioctl_niocregif(int32_t fd, void * param)
{
uint8_t portid;
int32_t rc;
uint32_t idx;
struct nmreq *req;
req = (struct nmreq *)param;
if ((rc = check_nmreq(req, &portid)) != 0)
return rc;
idx = FD_TO_IDX(fd);
rte_spinlock_lock(&netmap_lock);
rc = netmap_regif(req, idx, portid);
rte_spinlock_unlock(&netmap_lock);
return rc;
}
static void
netmap_unregif(uint32_t idx, uint32_t port)
{
fd_port[idx].port = FD_PORT_RSRV;
ports[port].fd = UINT32_MAX;
rte_eth_dev_stop((uint8_t)port);
}
static int
ioctl_niocunregif(int fd)
{
uint32_t idx, port;
int32_t rc;
idx = FD_TO_IDX(fd);
rte_spinlock_lock(&netmap_lock);
port = fd_port[idx].port;
if (port < RTE_DIM(ports) && ports[port].fd == idx) {
netmap_unregif(idx, port);
rc = 0;
} else {
RTE_LOG(ERR, USER1,
"%s: %d is not associated with valid port\n",
__func__, fd);
rc = -EINVAL;
}
rte_spinlock_unlock(&netmap_lock);
return rc;
}
static inline int
rx_sync_ring(struct netmap_ring *ring, uint8_t port, uint16_t ring_number,
uint16_t max_burst)
{
int32_t i, n_rx;
uint16_t burst_size;
uint32_t cur_slot, n_free_slots;
struct rte_mbuf *rx_mbufs[COMPAT_NETMAP_MAX_BURST];
n_free_slots = ring->num_slots - (ring->avail + ring->reserved);
n_free_slots = RTE_MIN(n_free_slots, max_burst);
cur_slot = (ring->cur + ring->avail) & (ring->num_slots - 1);
while (n_free_slots) {
burst_size = (uint16_t)RTE_MIN(n_free_slots, RTE_DIM(rx_mbufs));
/* receive up to burst_size packets from the NIC's queue */
n_rx = rte_eth_rx_burst(port, ring_number, rx_mbufs,
burst_size);
if (n_rx == 0)
return 0;
if (unlikely(n_rx < 0))
return -1;
/* Put those n_rx packets in the Netmap structures */
for (i = 0; i < n_rx ; i++) {
mbuf_to_slot(rx_mbufs[i], ring, cur_slot);
rte_pktmbuf_free(rx_mbufs[i]);
cur_slot = NETMAP_RING_NEXT(ring, cur_slot);
}
/* Update the Netmap ring structure to reflect the change */
ring->avail += n_rx;
n_free_slots -= n_rx;
}
return 0;
}
static inline int
rx_sync_if(uint32_t port)
{
uint16_t burst;
uint32_t i, rc;
struct netmap_if *nifp;
struct netmap_ring *r;
nifp = ports[port].nmif;
burst = ports[port].rx_burst;
rc = 0;
for (i = 0; i < nifp->ni_rx_rings + 1; i++) {
r = NETMAP_RXRING(nifp, i);
rx_sync_ring(r, (uint8_t)port, (uint16_t)i, burst);
rc += r->avail;
}
return rc;
}
static int
ioctl_niocrxsync(int fd)
{
uint32_t idx, port;
idx = FD_TO_IDX(fd);
if ((port = fd_port[idx].port) < RTE_DIM(ports) &&
ports[port].fd == idx) {
return rx_sync_if(fd_port[idx].port);
} else {
return -EINVAL;
}
}
static int
tx_sync_ring(struct netmap_ring *ring, uint8_t port, uint16_t ring_number,
struct rte_mempool *pool, uint16_t max_burst)
{
uint32_t i, n_tx;
uint16_t burst_size;
uint32_t cur_slot, n_used_slots;
struct rte_mbuf *tx_mbufs[COMPAT_NETMAP_MAX_BURST];
n_used_slots = ring->num_slots - ring->avail;
n_used_slots = RTE_MIN(n_used_slots, max_burst);
cur_slot = (ring->cur + ring->avail) & (ring->num_slots - 1);
while (n_used_slots) {
burst_size = (uint16_t)RTE_MIN(n_used_slots, RTE_DIM(tx_mbufs));
for (i = 0; i < burst_size; i++) {
tx_mbufs[i] = rte_pktmbuf_alloc(pool);
if (tx_mbufs[i] == NULL)
goto err;
slot_to_mbuf(ring, cur_slot, tx_mbufs[i]);
cur_slot = NETMAP_RING_NEXT(ring, cur_slot);
}
n_tx = rte_eth_tx_burst(port, ring_number, tx_mbufs,
burst_size);
/* Update the Netmap ring structure to reflect the change */
ring->avail += n_tx;
n_used_slots -= n_tx;
/* Return the mbufs that failed to transmit to their pool */
if (unlikely(n_tx != burst_size)) {
for (i = n_tx; i < burst_size; i++)
rte_pktmbuf_free(tx_mbufs[i]);
break;
}
}
return 0;
err:
for (; i == 0; --i)
rte_pktmbuf_free(tx_mbufs[i]);
RTE_LOG(ERR, USER1,
"Couldn't get mbuf from mempool is the mempool too small?\n");
return -1;
}
static int
tx_sync_if(uint32_t port)
{
uint16_t burst;
uint32_t i, rc;
struct netmap_if *nifp;
struct netmap_ring *r;
struct rte_mempool *mp;
nifp = ports[port].nmif;
mp = ports[port].pool;
burst = ports[port].tx_burst;
rc = 0;
for (i = 0; i < nifp->ni_tx_rings + 1; i++) {
r = NETMAP_TXRING(nifp, i);
tx_sync_ring(r, (uint8_t)port, (uint16_t)i, mp, burst);
rc += r->avail;
}
return rc;
}
static inline int
ioctl_nioctxsync(int fd)
{
uint32_t idx, port;
idx = FD_TO_IDX(fd);
if ((port = fd_port[idx].port) < RTE_DIM(ports) &&
ports[port].fd == idx) {
return tx_sync_if(fd_port[idx].port);
} else {
return -EINVAL;
}
}
int
rte_netmap_init(const struct rte_netmap_conf *conf)
{
size_t buf_ofs, nmif_sz, sz;
size_t port_rings, port_slots, port_bufs;
uint32_t i, port_num;
port_num = RTE_MAX_ETHPORTS;
port_rings = 2 * conf->max_rings;
port_slots = port_rings * conf->max_slots;
port_bufs = port_slots;
nmif_sz = NETMAP_IF_RING_OFS(port_rings, port_rings, port_slots);
sz = nmif_sz * port_num;
buf_ofs = RTE_ALIGN_CEIL(sz, RTE_CACHE_LINE_SIZE);
sz = buf_ofs + port_bufs * conf->max_bufsz * port_num;
if (sz > UINT32_MAX ||
(netmap.mem = rte_zmalloc_socket(__func__, sz,
RTE_CACHE_LINE_SIZE, conf->socket_id)) == NULL) {
RTE_LOG(ERR, USER1, "%s: failed to allocate %zu bytes\n",
__func__, sz);
return -ENOMEM;
}
netmap.mem_sz = sz;
netmap.netif_memsz = nmif_sz;
netmap.buf_start = (uintptr_t)netmap.mem + buf_ofs;
netmap.conf = *conf;
rte_spinlock_init(&netmap_lock);
/* Mark all ports as unused and set NETIF pointer. */
for (i = 0; i != RTE_DIM(ports); i++) {
ports[i].fd = UINT32_MAX;
ports[i].nmif = (struct netmap_if *)
((uintptr_t)netmap.mem + nmif_sz * i);
}
/* Mark all fd_ports as unused. */
for (i = 0; i != RTE_DIM(fd_port); i++) {
fd_port[i].port = FD_PORT_FREE;
}
return 0;
}
int
rte_netmap_init_port(uint8_t portid, const struct rte_netmap_port_conf *conf)
{
int32_t ret;
uint16_t i;
uint16_t rx_slots, tx_slots;
if (conf == NULL ||
portid >= RTE_DIM(ports) ||
conf->nr_tx_rings > netmap.conf.max_rings ||
conf->nr_rx_rings > netmap.conf.max_rings) {
RTE_LOG(ERR, USER1, "%s(%hhu): invalid parameters\n",
__func__, portid);
return -EINVAL;
}
rx_slots = (uint16_t)rte_align32pow2(conf->nr_rx_slots);
tx_slots = (uint16_t)rte_align32pow2(conf->nr_tx_slots);
if (tx_slots > netmap.conf.max_slots ||
rx_slots > netmap.conf.max_slots) {
RTE_LOG(ERR, USER1, "%s(%hhu): invalid parameters\n",
__func__, portid);
return -EINVAL;
}
ret = rte_eth_dev_configure(portid, conf->nr_rx_rings,
conf->nr_tx_rings, conf->eth_conf);
if (ret < 0) {
RTE_LOG(ERR, USER1, "Couldn't configure port %hhu\n", portid);
return ret;
}
for (i = 0; i < conf->nr_tx_rings; i++) {
ret = rte_eth_tx_queue_setup(portid, i, tx_slots,
conf->socket_id, NULL);
if (ret < 0) {
RTE_LOG(ERR, USER1,
"Couldn't configure TX queue %"PRIu16" of "
"port %"PRIu8"\n",
i, portid);
return ret;
}
ret = rte_eth_rx_queue_setup(portid, i, rx_slots,
conf->socket_id, NULL, conf->pool);
if (ret < 0) {
RTE_LOG(ERR, USER1,
"Couldn't configure RX queue %"PRIu16" of "
"port %"PRIu8"\n",
i, portid);
return ret;
}
}
/* copy config to the private storage. */
ports[portid].eth_conf = conf->eth_conf[0];
ports[portid].pool = conf->pool;
ports[portid].socket_id = conf->socket_id;
ports[portid].nr_tx_rings = conf->nr_tx_rings;
ports[portid].nr_rx_rings = conf->nr_rx_rings;
ports[portid].nr_tx_slots = tx_slots;
ports[portid].nr_rx_slots = rx_slots;
ports[portid].tx_burst = conf->tx_burst;
ports[portid].rx_burst = conf->rx_burst;
return 0;
}
int
rte_netmap_close(__rte_unused int fd)
{
int32_t rc;
rte_spinlock_lock(&netmap_lock);
rc = fd_release(fd);
rte_spinlock_unlock(&netmap_lock);
if (rc < 0) {
errno =-rc;
rc = -1;
}
return rc;
}
int rte_netmap_ioctl(int fd, uint32_t op, void *param)
{
int ret;
if (!FD_VALID(fd)) {
errno = EBADF;
return -1;
}
switch (op) {
case NIOCGINFO:
ret = ioctl_niocginfo(fd, param);
break;
case NIOCREGIF:
ret = ioctl_niocregif(fd, param);
break;
case NIOCUNREGIF:
ret = ioctl_niocunregif(fd);
break;
case NIOCRXSYNC:
ret = ioctl_niocrxsync(fd);
break;
case NIOCTXSYNC:
ret = ioctl_nioctxsync(fd);
break;
default:
ret = -ENOTTY;
}
if (ret < 0) {
errno = -ret;
ret = -1;
} else {
ret = 0;
}
return ret;
}
void *
rte_netmap_mmap(void *addr, size_t length,
int prot, int flags, int fd, off_t offset)
{
static const int cprot = PROT_WRITE | PROT_READ;
if (!FD_VALID(fd) || length + offset > netmap.mem_sz ||
(prot & cprot) != cprot ||
((flags & MAP_FIXED) != 0 && addr != NULL)) {
errno = EINVAL;
return MAP_FAILED;
}
return (void *)((uintptr_t)netmap.mem + (uintptr_t)offset);
}
int
rte_netmap_open(__rte_unused const char *pathname, __rte_unused int flags)
{
int fd;
rte_spinlock_lock(&netmap_lock);
fd = fd_reserve();
rte_spinlock_unlock(&netmap_lock);
if (fd < 0) {
errno = -fd;
fd = -1;
}
return fd;
}
int
rte_netmap_poll(struct pollfd *fds, nfds_t nfds, int timeout)
{
int32_t count_it, ret;
uint32_t i, idx, port;
uint32_t want_rx, want_tx;
if (timeout > 0)
return -1;
ret = 0;
do {
for (i = 0; i < nfds; i++) {
count_it = 0;
if (!FD_VALID(fds[i].fd) || fds[i].events == 0) {
fds[i].revents = 0;
continue;
}
idx = FD_TO_IDX(fds[i].fd);
if ((port = fd_port[idx].port) >= RTE_DIM(ports) ||
ports[port].fd != idx) {
fds[i].revents |= POLLERR;
ret++;
continue;
}
want_rx = fds[i].events & (POLLIN | POLLRDNORM);
want_tx = fds[i].events & (POLLOUT | POLLWRNORM);
if (want_rx && rx_sync_if(port) > 0) {
fds[i].revents = (uint16_t)
(fds[i].revents | want_rx);
count_it = 1;
}
if (want_tx && tx_sync_if(port) > 0) {
fds[i].revents = (uint16_t)
(fds[i].revents | want_tx);
count_it = 1;
}
ret += count_it;
}
}
while ((ret == 0 && timeout < 0) || timeout);
return ret;
}