From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id AED95CD6E4A for ; Tue, 2 Jun 2026 04:55:02 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wUH8y-00008Y-55; Tue, 02 Jun 2026 00:54:24 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wUH8u-00007j-Ab for qemu-devel@nongnu.org; Tue, 02 Jun 2026 00:54:21 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wUH8s-0001RD-2x for qemu-devel@nongnu.org; Tue, 02 Jun 2026 00:54:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1780376056; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ygYoqFHcospyqBOi/iJELgsJMGA+Dql+S93uYrPF/cc=; b=BeAHp7e8d7GwE/orNYq6dpeadh1R1nZTXyD6+0RjvgWOk0UkWuYslW0JZqiZZ7IqDLpzDP xlptTFIy0K6iTW2x74WA/qcWoH9UYAtFb3E1CbAhGbRFyRa9Fkce2dX+XrQLpyQAjWMY1p ZXAFXJtDquPlhHj84gih4XTTfeIVhDo= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-663-IVxeFcnpOIOhd3I5cRs8aA-1; Tue, 02 Jun 2026 00:54:14 -0400 X-MC-Unique: IVxeFcnpOIOhd3I5cRs8aA-1 X-Mimecast-MFC-AGG-ID: IVxeFcnpOIOhd3I5cRs8aA_1780376053 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0313619560AA; Tue, 2 Jun 2026 04:54:13 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.44.22.2]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1379C1800465; Tue, 2 Jun 2026 04:54:11 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 556A221E6A01; Tue, 02 Jun 2026 06:54:09 +0200 (CEST) From: Markus Armbruster To: Mitsuru Kariya Cc: qemu-devel@nongnu.org, Daniel P. =?utf-8?Q?Berrang=C3=A9?= , Paolo Bonzini , =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Pierrick Bouvier , Eric Blake , Fabiano Rosas , Laurent Vivier , Peter Xu , Jason Wang Subject: Re: [PATCH 4/5] util/qemu-sockets: add TCP_USER_TIMEOUT support In-Reply-To: <20260524073442.435408-5-Mitsuru.Kariya@oss.nttdata.com> (Mitsuru Kariya's message of "Sun, 24 May 2026 16:34:41 +0900") References: <20260524073442.435408-1-Mitsuru.Kariya@oss.nttdata.com> <20260524073442.435408-5-Mitsuru.Kariya@oss.nttdata.com> Date: Tue, 02 Jun 2026 06:54:09 +0200 Message-ID: <87se758rv2.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 8 X-Spam_score: 0.8 X-Spam_bar: / X-Spam_report: (0.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.445, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Mitsuru Kariya writes: > The TCP_USER_TIMEOUT socket option (Linux-only) specifies the maximum > amount of time in milliseconds that transmitted data may remain > unacknowledged, or buffered data may remain untransmitted, before TCP > forcibly closes the connection and returns ETIMEDOUT to the > application. Without it, a peer that becomes silently unreachable can > take well over an hour to be noticed (the kernel default), which is > particularly painful for use cases like QEMU live migration. > > Expose user-timeout as a new optional InetSocketAddress member, gated > on a new HAVE_TCP_USER_TIMEOUT meson check, and apply it in > inet_set_sockopts() alongside the existing keep-alive options. Plumb > the same option through the legacy QemuOpts-based inet_parse() path so > that URI-style users (-incoming tcp:, migrate tcp:, HMP > nbd_server_start, ...) can set it too. > > Update the documentation for -netdev stream (addr.user-timeout=N) and > -incoming tcp: (user-timeout=N, flat key as for the other inet_opts > entries), and extend test_inet_parse_all_options_good accordingly. > > Signed-off-by: Mitsuru Kariya > --- > meson.build | 2 ++ > qapi/sockets.json | 7 +++++++ > qemu-options.hx | 13 +++++++++---- > tests/unit/test-util-sockets.c | 13 +++++++++++++ > util/qemu-sockets.c | 24 ++++++++++++++++++++++++ > 5 files changed, 55 insertions(+), 4 deletions(-) > > diff --git a/meson.build b/meson.build > index eb07491819..c5afe8754d 100644 > --- a/meson.build > +++ b/meson.build > @@ -2726,6 +2726,8 @@ config_host_data.set('HAVE_TCP_KEEPINTVL', > #endif > int main(void) { return 0; }''', > name: 'Win32 TCP_KEEPINTVL')) > +config_host_data.set('HAVE_TCP_USER_TIMEOUT', > + cc.has_header_symbol('netinet/tcp.h', 'TCP_USER_TIMEOUT')) > > # has_member > config_host_data.set('HAVE_SIGEV_NOTIFY_THREAD_ID', > diff --git a/qapi/sockets.json b/qapi/sockets.json > index 473be2ac58..543689a2c7 100644 > --- a/qapi/sockets.json > +++ b/qapi/sockets.json > @@ -79,6 +79,12 @@ > # defined (this includes Linux, Windows, macOS, FreeBSD, but not > # OpenBSD). When set to 0, system setting is used. (Since 10.1) > # > +# @user-timeout: time in milliseconds that transmitted data may remain > +# unacknowledged before the connection is closed. Only supported > +# for TCP sockets on systems where TCP_USER_TIMEOUT socket option > +# is defined (Linux only). When set to 0, system setting is used. > +# (Since 11.1) > +# Actually, it's "transmitted data may remain unacknowledged, or buffered data may remain untransmitted". Moreover, the interaction with @keep-alive is not mentioned. We want to keep the description reasonably short, though. Have it point to tcp(7) for details? Perhaps something like # @user-timeout: time in milliseconds that transmitted data may remain # unacknowledged, or buffered data may remain untransmitted before # the connection is closed. See tcp(7) for details. Only # supported when the host provides socket option TCP_USER_TIMEOUT # (Linux). 0 means system default. (default 0) (since 11.1) What do you think? > # @mptcp: enable multi-path TCP. (Since 6.1) > # > # Since: 1.3 > @@ -94,6 +100,7 @@ > '*keep-alive-count': { 'type': 'uint32', 'if': 'HAVE_TCP_KEEPCNT' }, > '*keep-alive-idle': { 'type': 'uint32', 'if': 'HAVE_TCP_KEEPIDLE' }, > '*keep-alive-interval': { 'type': 'uint32', 'if': 'HAVE_TCP_KEEPINTVL' }, > + '*user-timeout': { 'type': 'uint32', 'if': 'HAVE_TCP_USER_TIMEOUT' }, > '*mptcp': { 'type': 'bool', 'if': 'HAVE_IPPROTO_MPTCP' } } } > > ## > diff --git a/qemu-options.hx b/qemu-options.hx > index d2b816e16f..63587cccd3 100644 > --- a/qemu-options.hx > +++ b/qemu-options.hx > @@ -3034,7 +3034,7 @@ DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, > "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" > " configure a network backend to connect to another network\n" > " using an UDP tunnel\n" > - "-netdev stream,id=str[,server=on|off],addr.type=inet,addr.host=host,addr.port=port[,addr.to=maxport][,addr.numeric=on|off][,addr.keep-alive=on|off][,addr.keep-alive-count=count][,addr.keep-alive-idle=idle][,addr.keep-alive-interval=interval][,addr.mptcp=on|off][,addr.ipv4=on|off][,addr.ipv6=on|off][,reconnect-ms=milliseconds]\n" > + "-netdev stream,id=str[,server=on|off],addr.type=inet,addr.host=host,addr.port=port[,addr.to=maxport][,addr.numeric=on|off][,addr.keep-alive=on|off][,addr.keep-alive-count=count][,addr.keep-alive-idle=idle][,addr.keep-alive-interval=interval][,addr.user-timeout=timeout][,addr.mptcp=on|off][,addr.ipv4=on|off][,addr.ipv6=on|off][,reconnect-ms=milliseconds]\n" > "-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,addr.abstract=on|off][,addr.tight=on|off][,reconnect-ms=milliseconds]\n" > "-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor[,reconnect-ms=milliseconds]\n" > " configure a network backend to connect to another network\n" > @@ -3640,7 +3640,7 @@ SRST > -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ > -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 > > -``-netdev stream,id=str[,server=on|off],addr.type=inet,addr.host=host,addr.port=port[,addr.to=maxport][,addr.numeric=on|off][,addr.keep-alive=on|off][,addr.keep-alive-count=count][,addr.keep-alive-idle=idle][,addr.keep-alive-interval=interval][,addr.mptcp=on|off][,addr.ipv4=on|off][,addr.ipv6=on|off][,reconnect-ms=milliseconds]`` > +``-netdev stream,id=str[,server=on|off],addr.type=inet,addr.host=host,addr.port=port[,addr.to=maxport][,addr.numeric=on|off][,addr.keep-alive=on|off][,addr.keep-alive-count=count][,addr.keep-alive-idle=idle][,addr.keep-alive-interval=interval][,addr.user-timeout=timeout][,addr.mptcp=on|off][,addr.ipv4=on|off][,addr.ipv6=on|off][,reconnect-ms=milliseconds]`` > Configure a network backend to connect to another QEMU virtual machine or a proxy using a TCP/IP socket. > > ``server=on|off`` > @@ -3670,6 +3670,11 @@ SRST > time in seconds between individual keep-alive packets. > Set to 0 to use the system default. (default: 0) > > + ``addr.user-timeout=timeout`` > + time in milliseconds that transmitted data may remain unacknowledged > + before the connection is forcibly closed. > + Set to 0 to use the system default. (default: 0) > + If you improve the description in net.json, update this one to match it. > ``addr.mptcp=on|off`` > enable multipath TCP > > @@ -5365,7 +5370,7 @@ SRST > ERST > > DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ > - "-incoming tcp:[host]:port[,to=maxport][,numeric=on|off][,keep-alive=on|off][,keep-alive-count=count][,keep-alive-idle=idle][,keep-alive-interval=interval][,mptcp=on|off][,ipv4=on|off][,ipv6=on|off]\n" \ > + "-incoming tcp:[host]:port[,to=maxport][,numeric=on|off][,keep-alive=on|off][,keep-alive-count=count][,keep-alive-idle=idle][,keep-alive-interval=interval][,user-timeout=timeout][,mptcp=on|off][,ipv4=on|off][,ipv6=on|off]\n" \ > "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ > "-incoming unix:socketpath\n" \ > " prepare for incoming migration, listen on\n" \ > @@ -5387,7 +5392,7 @@ migration channel types. The channel type is specified in , > or is 'main' for all other forms of -incoming. If multiple -incoming > options are specified for a channel type, the last one takes precedence. > > -``-incoming tcp:[host]:port[,to=maxport][,numeric=on|off][,keep-alive=on|off][,keep-alive-count=count][,keep-alive-idle=idle][,keep-alive-interval=interval][,mptcp=on|off][,ipv4=on|off][,ipv6=on|off]`` > +``-incoming tcp:[host]:port[,to=maxport][,numeric=on|off][,keep-alive=on|off][,keep-alive-count=count][,keep-alive-idle=idle][,keep-alive-interval=interval][,user-timeout=timeout][,mptcp=on|off][,ipv4=on|off][,ipv6=on|off]`` > \ > ``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` > Prepare for incoming migration, listen on a given tcp port. [...]