On 03.03.25 17:33, Juraj Marcin wrote:
The default idle period for TCP connection could be even 2 hours.
However, in some cases, the application needs to be aware of a
connection issue much sooner.
This is the case, for example, for postcopy live migration. If there is
no traffic from the migration destination guest (server-side) to the
migration source guest (client-side), the destination keeps waiting for
pages indefinitely and does not switch to the postcopy-paused state.
This can happen, for example, if the destination QEMU instance is
started with '-S' command line option and the machine is not started yet
or if the machine is idle and produces no new page faults for
not-yet-migrated pages.
This patch introduces a new inet socket parameter on platforms where
TCP_KEEPIDLE is defined and passes the configured value to the
TCP_KEEPIDLE socket option when a client-side or server-side socket is
created.
The default value is 0, which means system configuration is used, and no
custom value is set.
Signed-off-by: Juraj Marcin <jmar...@redhat.com>
---
io/dns-resolver.c | 4 ++++
meson.build | 2 ++
qapi/sockets.json | 5 +++++
util/qemu-sockets.c | 39 +++++++++++++++++++++++++++++++++++++++
4 files changed, 50 insertions(+)
diff --git a/io/dns-resolver.c b/io/dns-resolver.c
index ee7403b65b..03c59673f0 100644
--- a/io/dns-resolver.c
+++ b/io/dns-resolver.c
@@ -128,6 +128,10 @@ static int
qio_dns_resolver_lookup_sync_inet(QIODNSResolver *resolver,
#endif
.has_keep_alive = iaddr->has_keep_alive,
.keep_alive = iaddr->keep_alive,
+#ifdef HAVE_TCP_KEEPIDLE
+ .has_keep_alive_idle_period = iaddr->has_keep_alive_idle_period,
+ .keep_alive_idle_period = iaddr->keep_alive_idle_period,
+#endif
};
(*addrs)[i] = newaddr;
diff --git a/meson.build b/meson.build
index 0ee79c664d..ca726f317f 100644
--- a/meson.build
+++ b/meson.build
@@ -2724,6 +2724,8 @@ config_host_data.set('HAVE_OPTRESET',
cc.has_header_symbol('getopt.h', 'optreset'))
config_host_data.set('HAVE_IPPROTO_MPTCP',
cc.has_header_symbol('netinet/in.h', 'IPPROTO_MPTCP'))
+config_host_data.set('HAVE_TCP_KEEPIDLE',
+ cc.has_header_symbol('netinet/tcp.h', 'TCP_KEEPIDLE'))
# has_member
config_host_data.set('HAVE_SIGEV_NOTIFY_THREAD_ID',
diff --git a/qapi/sockets.json b/qapi/sockets.json
index eb50f64e3a..ddd82b1e66 100644
--- a/qapi/sockets.json
+++ b/qapi/sockets.json
@@ -59,6 +59,10 @@
# @keep-alive: enable keep-alive when connecting to/listening on this socket.
# (Since 4.2, not supported for listening sockets until 10.0)
#
+# @keep-alive-idle-period: time in seconds the connection needs to be idle
+# before sending a keepalive packet. Only supported for TCP sockets on
+# systems where TCP_KEEPIDLE socket option is defined. (Since 10.0)
+#
# @mptcp: enable multi-path TCP. (Since 6.1)
#
# Since: 1.3
@@ -71,6 +75,7 @@
'*ipv4': 'bool',
'*ipv6': 'bool',
'*keep-alive': 'bool',
+ '*keep-alive-idle-period': { 'type': 'uint32', 'if': 'HAVE_TCP_KEEPIDLE' },
'*mptcp': { 'type': 'bool', 'if': 'HAVE_IPPROTO_MPTCP' } } }
##
diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c
index c30e4ac2ce..edcda846ef 100644
--- a/util/qemu-sockets.c
+++ b/util/qemu-sockets.c
@@ -349,6 +349,18 @@ listen_ok:
slisten = -1;
goto exit;
}
+#ifdef HAVE_TCP_KEEPIDLE
+ if (saddr->has_keep_alive_idle_period &&
saddr->keep_alive_idle_period) {
+ int keepidle = saddr->has_keep_alive_idle_period;
+ ret = setsockopt(slisten, IPPROTO_TCP, TCP_KEEPIDLE, &keepidle,
sizeof(keepidle));
+ if (ret < 0) {
+ error_setg_errno(errp, errno, "Unable to set TCP_KEEPIDLE");
+ close(slisten);
+ slisten = -1;
+ goto exit;
+ }
+ }
+#endif
}
exit:
freeaddrinfo(res);
@@ -492,6 +504,17 @@ int inet_connect_saddr(InetSocketAddress *saddr, Error
**errp)
close(sock);
return -1;
}
+#ifdef HAVE_TCP_KEEPIDLE
+ if (saddr->has_keep_alive_idle_period &&
saddr->keep_alive_idle_period) {
+ int keepidle = saddr->keep_alive_idle_period;
+ ret = setsockopt(sock, IPPROTO_TCP, TCP_KEEPIDLE, &keepidle,
sizeof(keepidle));
+ if (ret < 0) {
+ error_setg_errno(errp, errno, "Unsable to set TCP_KEEPIDLE");
+ close(sock);
+ return -1;
+ }
+ }
+#endif
}
Looks like we need some inet_setsockopt(*saddr) {}, which set both options and
called from both client and server sockets, to avoid duplication.
return sock;
@@ -698,6 +721,22 @@ int inet_parse(InetSocketAddress *addr, const char *str,
Error **errp)
}
addr->has_keep_alive = true;
}
+#ifdef HAVE_TCP_KEEPIDLE
+ begin = strstr(optstr, ",keep-alive-idle-period=");
+ if (begin) {
+ begin += strlen(",keep-alive-idle-period=");
+ if (sscanf(begin, "%" PRIu32 "%n", &addr->keep_alive_idle_period,
&pos) != 1 ||
+ (begin[pos] != '\0' && begin[pos] != ',')) {
+ error_setg(errp, "error parsing keep-alive-idle-period argument");
+ return -1;
+ }
+ if (addr->keep_alive_idle_period > INT_MAX) {
+ error_setg(errp, "keep-alive-idle-period value is too large");
+ return -1;
+ }
+ addr->has_keep_alive_idle_period = true;
+ }
+#endif
#ifdef HAVE_IPPROTO_MPTCP
begin = strstr(optstr, ",mptcp");
if (begin) {
--
Best regards,
Vladimir
