qemu/net/stream.c
Daniel P. Berrangé 9cd67f0cce net: handle QIOTask completion to report useful error message
The network stream backend uses the async QIO socket APIs for listening
and connecting sockets. It does not check the task object completion
status, however, instead just looking at whether the socket FD is -1
or not.

By checking the task completion, we can set a useful error message for
users instead of the non-actionable "connection error" string.

eg so users will see:

(qemu) info network
net: index=0,type=stream,error: Failed to connect to '/foo.unix': No such file or directory

Signed-off-by: "Daniel P. Berrangé" <berrange@redhat.com>
Message-ID: <20240104162942.211458-6-berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2024-01-11 11:39:26 +01:00

446 lines
14 KiB
C

/*
* QEMU System Emulator
*
* Copyright (c) 2003-2008 Fabrice Bellard
* Copyright (c) 2022 Red Hat, Inc.
*
* 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 "qemu/osdep.h"
#include "net/net.h"
#include "clients.h"
#include "monitor/monitor.h"
#include "qapi/error.h"
#include "qemu/error-report.h"
#include "qemu/option.h"
#include "qemu/sockets.h"
#include "qemu/iov.h"
#include "qemu/main-loop.h"
#include "qemu/cutils.h"
#include "io/channel.h"
#include "io/channel-socket.h"
#include "io/net-listener.h"
#include "qapi/qapi-events-net.h"
#include "qapi/qapi-visit-sockets.h"
#include "qapi/clone-visitor.h"
typedef struct NetStreamState {
NetClientState nc;
QIOChannel *listen_ioc;
QIONetListener *listener;
QIOChannel *ioc;
guint ioc_read_tag;
guint ioc_write_tag;
SocketReadState rs;
unsigned int send_index; /* number of bytes sent*/
uint32_t reconnect;
guint timer_tag;
SocketAddress *addr;
} NetStreamState;
static void net_stream_listen(QIONetListener *listener,
QIOChannelSocket *cioc,
void *opaque);
static void net_stream_arm_reconnect(NetStreamState *s);
static gboolean net_stream_writable(QIOChannel *ioc,
GIOCondition condition,
gpointer data)
{
NetStreamState *s = data;
s->ioc_write_tag = 0;
qemu_flush_queued_packets(&s->nc);
return G_SOURCE_REMOVE;
}
static ssize_t net_stream_receive(NetClientState *nc, const uint8_t *buf,
size_t size)
{
NetStreamState *s = DO_UPCAST(NetStreamState, nc, nc);
uint32_t len = htonl(size);
struct iovec iov[] = {
{
.iov_base = &len,
.iov_len = sizeof(len),
}, {
.iov_base = (void *)buf,
.iov_len = size,
},
};
struct iovec local_iov[2];
unsigned int nlocal_iov;
size_t remaining;
ssize_t ret;
remaining = iov_size(iov, 2) - s->send_index;
nlocal_iov = iov_copy(local_iov, 2, iov, 2, s->send_index, remaining);
ret = qio_channel_writev(s->ioc, local_iov, nlocal_iov, NULL);
if (ret == QIO_CHANNEL_ERR_BLOCK) {
ret = 0; /* handled further down */
}
if (ret == -1) {
s->send_index = 0;
return -errno;
}
if (ret < (ssize_t)remaining) {
s->send_index += ret;
s->ioc_write_tag = qio_channel_add_watch(s->ioc, G_IO_OUT,
net_stream_writable, s, NULL);
return 0;
}
s->send_index = 0;
return size;
}
static gboolean net_stream_send(QIOChannel *ioc,
GIOCondition condition,
gpointer data);
static void net_stream_send_completed(NetClientState *nc, ssize_t len)
{
NetStreamState *s = DO_UPCAST(NetStreamState, nc, nc);
if (!s->ioc_read_tag) {
s->ioc_read_tag = qio_channel_add_watch(s->ioc, G_IO_IN,
net_stream_send, s, NULL);
}
}
static void net_stream_rs_finalize(SocketReadState *rs)
{
NetStreamState *s = container_of(rs, NetStreamState, rs);
if (qemu_send_packet_async(&s->nc, rs->buf,
rs->packet_len,
net_stream_send_completed) == 0) {
if (s->ioc_read_tag) {
g_source_remove(s->ioc_read_tag);
s->ioc_read_tag = 0;
}
}
}
static gboolean net_stream_send(QIOChannel *ioc,
GIOCondition condition,
gpointer data)
{
NetStreamState *s = data;
int size;
int ret;
char buf1[NET_BUFSIZE];
const char *buf;
size = qio_channel_read(s->ioc, buf1, sizeof(buf1), NULL);
if (size < 0) {
if (errno != EWOULDBLOCK) {
goto eoc;
}
} else if (size == 0) {
/* end of connection */
eoc:
s->ioc_read_tag = 0;
if (s->ioc_write_tag) {
g_source_remove(s->ioc_write_tag);
s->ioc_write_tag = 0;
}
if (s->listener) {
qemu_set_info_str(&s->nc, "listening");
qio_net_listener_set_client_func(s->listener, net_stream_listen,
s, NULL);
}
object_unref(OBJECT(s->ioc));
s->ioc = NULL;
net_socket_rs_init(&s->rs, net_stream_rs_finalize, false);
s->nc.link_down = true;
qapi_event_send_netdev_stream_disconnected(s->nc.name);
net_stream_arm_reconnect(s);
return G_SOURCE_REMOVE;
}
buf = buf1;
ret = net_fill_rstate(&s->rs, (const uint8_t *)buf, size);
if (ret == -1) {
goto eoc;
}
return G_SOURCE_CONTINUE;
}
static void net_stream_cleanup(NetClientState *nc)
{
NetStreamState *s = DO_UPCAST(NetStreamState, nc, nc);
if (s->timer_tag) {
g_source_remove(s->timer_tag);
s->timer_tag = 0;
}
if (s->addr) {
qapi_free_SocketAddress(s->addr);
s->addr = NULL;
}
if (s->ioc) {
if (QIO_CHANNEL_SOCKET(s->ioc)->fd != -1) {
if (s->ioc_read_tag) {
g_source_remove(s->ioc_read_tag);
s->ioc_read_tag = 0;
}
if (s->ioc_write_tag) {
g_source_remove(s->ioc_write_tag);
s->ioc_write_tag = 0;
}
}
object_unref(OBJECT(s->ioc));
s->ioc = NULL;
}
if (s->listen_ioc) {
if (s->listener) {
qio_net_listener_disconnect(s->listener);
object_unref(OBJECT(s->listener));
s->listener = NULL;
}
object_unref(OBJECT(s->listen_ioc));
s->listen_ioc = NULL;
}
}
static NetClientInfo net_stream_info = {
.type = NET_CLIENT_DRIVER_STREAM,
.size = sizeof(NetStreamState),
.receive = net_stream_receive,
.cleanup = net_stream_cleanup,
};
static void net_stream_listen(QIONetListener *listener,
QIOChannelSocket *cioc,
void *opaque)
{
NetStreamState *s = opaque;
SocketAddress *addr;
char *uri;
object_ref(OBJECT(cioc));
qio_net_listener_set_client_func(s->listener, NULL, s, NULL);
s->ioc = QIO_CHANNEL(cioc);
qio_channel_set_name(s->ioc, "stream-server");
s->nc.link_down = false;
s->ioc_read_tag = qio_channel_add_watch(s->ioc, G_IO_IN, net_stream_send,
s, NULL);
if (cioc->localAddr.ss_family == AF_UNIX) {
addr = qio_channel_socket_get_local_address(cioc, NULL);
} else {
addr = qio_channel_socket_get_remote_address(cioc, NULL);
}
g_assert(addr != NULL);
uri = socket_uri(addr);
qemu_set_info_str(&s->nc, "%s", uri);
g_free(uri);
qapi_event_send_netdev_stream_connected(s->nc.name, addr);
qapi_free_SocketAddress(addr);
}
static void net_stream_server_listening(QIOTask *task, gpointer opaque)
{
NetStreamState *s = opaque;
QIOChannelSocket *listen_sioc = QIO_CHANNEL_SOCKET(s->listen_ioc);
SocketAddress *addr;
int ret;
Error *err = NULL;
if (qio_task_propagate_error(task, &err)) {
qemu_set_info_str(&s->nc, "error: %s", error_get_pretty(err));
error_free(err);
return;
}
addr = qio_channel_socket_get_local_address(listen_sioc, NULL);
g_assert(addr != NULL);
ret = qemu_socket_try_set_nonblock(listen_sioc->fd);
if (addr->type == SOCKET_ADDRESS_TYPE_FD && ret < 0) {
qemu_set_info_str(&s->nc, "can't use file descriptor %s (errno %d)",
addr->u.fd.str, -ret);
return;
}
g_assert(ret == 0);
qapi_free_SocketAddress(addr);
s->nc.link_down = true;
s->listener = qio_net_listener_new();
qemu_set_info_str(&s->nc, "listening");
net_socket_rs_init(&s->rs, net_stream_rs_finalize, false);
qio_net_listener_set_client_func(s->listener, net_stream_listen, s, NULL);
qio_net_listener_add(s->listener, listen_sioc);
}
static int net_stream_server_init(NetClientState *peer,
const char *model,
const char *name,
SocketAddress *addr,
Error **errp)
{
NetClientState *nc;
NetStreamState *s;
QIOChannelSocket *listen_sioc = qio_channel_socket_new();
nc = qemu_new_net_client(&net_stream_info, peer, model, name);
s = DO_UPCAST(NetStreamState, nc, nc);
qemu_set_info_str(&s->nc, "initializing");
s->listen_ioc = QIO_CHANNEL(listen_sioc);
qio_channel_socket_listen_async(listen_sioc, addr, 0,
net_stream_server_listening, s,
NULL, NULL);
return 0;
}
static void net_stream_client_connected(QIOTask *task, gpointer opaque)
{
NetStreamState *s = opaque;
QIOChannelSocket *sioc = QIO_CHANNEL_SOCKET(s->ioc);
SocketAddress *addr;
gchar *uri;
int ret;
Error *err = NULL;
if (qio_task_propagate_error(task, &err)) {
qemu_set_info_str(&s->nc, "error: %s", error_get_pretty(err));
error_free(err);
goto error;
}
addr = qio_channel_socket_get_remote_address(sioc, NULL);
g_assert(addr != NULL);
uri = socket_uri(addr);
qemu_set_info_str(&s->nc, "%s", uri);
g_free(uri);
ret = qemu_socket_try_set_nonblock(sioc->fd);
if (addr->type == SOCKET_ADDRESS_TYPE_FD && ret < 0) {
qemu_set_info_str(&s->nc, "can't use file descriptor %s (errno %d)",
addr->u.fd.str, -ret);
qapi_free_SocketAddress(addr);
goto error;
}
g_assert(ret == 0);
net_socket_rs_init(&s->rs, net_stream_rs_finalize, false);
/* Disable Nagle algorithm on TCP sockets to reduce latency */
qio_channel_set_delay(s->ioc, false);
s->ioc_read_tag = qio_channel_add_watch(s->ioc, G_IO_IN, net_stream_send,
s, NULL);
s->nc.link_down = false;
qapi_event_send_netdev_stream_connected(s->nc.name, addr);
qapi_free_SocketAddress(addr);
return;
error:
object_unref(OBJECT(s->ioc));
s->ioc = NULL;
net_stream_arm_reconnect(s);
}
static gboolean net_stream_reconnect(gpointer data)
{
NetStreamState *s = data;
QIOChannelSocket *sioc;
s->timer_tag = 0;
sioc = qio_channel_socket_new();
s->ioc = QIO_CHANNEL(sioc);
qio_channel_socket_connect_async(sioc, s->addr,
net_stream_client_connected, s,
NULL, NULL);
return G_SOURCE_REMOVE;
}
static void net_stream_arm_reconnect(NetStreamState *s)
{
if (s->reconnect && s->timer_tag == 0) {
qemu_set_info_str(&s->nc, "connecting");
s->timer_tag = g_timeout_add_seconds(s->reconnect,
net_stream_reconnect, s);
}
}
static int net_stream_client_init(NetClientState *peer,
const char *model,
const char *name,
SocketAddress *addr,
uint32_t reconnect,
Error **errp)
{
NetStreamState *s;
NetClientState *nc;
QIOChannelSocket *sioc = qio_channel_socket_new();
nc = qemu_new_net_client(&net_stream_info, peer, model, name);
s = DO_UPCAST(NetStreamState, nc, nc);
qemu_set_info_str(&s->nc, "connecting");
s->ioc = QIO_CHANNEL(sioc);
s->nc.link_down = true;
s->reconnect = reconnect;
if (reconnect) {
s->addr = QAPI_CLONE(SocketAddress, addr);
}
qio_channel_socket_connect_async(sioc, addr,
net_stream_client_connected, s,
NULL, NULL);
return 0;
}
int net_init_stream(const Netdev *netdev, const char *name,
NetClientState *peer, Error **errp)
{
const NetdevStreamOptions *sock;
assert(netdev->type == NET_CLIENT_DRIVER_STREAM);
sock = &netdev->u.stream;
if (!sock->has_server || !sock->server) {
return net_stream_client_init(peer, "stream", name, sock->addr,
sock->has_reconnect ? sock->reconnect : 0,
errp);
}
if (sock->has_reconnect) {
error_setg(errp, "'reconnect' option is incompatible with "
"socket in server mode");
return -1;
}
return net_stream_server_init(peer, "stream", name, sock->addr, errp);
}