Daniel P. Berrangé <berra...@redhat.com> writes:
> On Thu, Apr 08, 2021 at 08:11:59PM +0100, Dr. David Alan Gilbert (git) wrote:
>> From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
>>
>> Multipath TCP allows combining multiple interfaces/routes into a single
>> socket, with very little work for the user/admin.
>>
>> It's enabled by 'mptcp' on most socket addresses:
>>
>> ./qemu-system-x86_64 -nographic -incoming tcp:0:4444,mptcp
>>
>> Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
>> ---
>> io/dns-resolver.c | 2 ++
>> qapi/sockets.json | 5 ++++-
>> util/qemu-sockets.c | 34 ++++++++++++++++++++++++++++++++++
>> 3 files changed, 40 insertions(+), 1 deletion(-)
>>
>> diff --git a/io/dns-resolver.c b/io/dns-resolver.c
>> index 743a0efc87..b081e098bb 100644
>> --- a/io/dns-resolver.c
>> +++ b/io/dns-resolver.c
>> @@ -122,6 +122,8 @@ static int
>> qio_dns_resolver_lookup_sync_inet(QIODNSResolver *resolver,
>> .ipv4 = iaddr->ipv4,
>> .has_ipv6 = iaddr->has_ipv6,
>> .ipv6 = iaddr->ipv6,
>> + .has_mptcp = iaddr->has_mptcp,
>> + .mptcp = iaddr->mptcp,
>> };
>>
>> (*addrs)[i] = newaddr;
>> diff --git a/qapi/sockets.json b/qapi/sockets.json
>> index 2e83452797..43122a38bf 100644
>> --- a/qapi/sockets.json
>> +++ b/qapi/sockets.json
>> @@ -57,6 +57,8 @@
>> # @keep-alive: enable keep-alive when connecting to this socket. Not
>> supported
>> # for passive sockets. (Since 4.2)
>> #
>> +# @mptcp: enable multi-path TCP. (Since 6.0)
>> +#
>> # Since: 1.3
>> ##
>> { 'struct': 'InetSocketAddress',
>> @@ -66,7 +68,8 @@
>> '*to': 'uint16',
>> '*ipv4': 'bool',
>> '*ipv6': 'bool',
>> - '*keep-alive': 'bool' } }
>> + '*keep-alive': 'bool',
>> + '*mptcp': 'bool' } }
>
> I think this would need to be
>
> '*mptcp': { 'type': 'bool', 'if': 'IPPROTO_MPTCP' }
>
> so that mgmt apps can probe when it truely is supported or not for
> this build
Yes. Instance of a somewhat common anti-pattern "declare
unconditionally (this hunk), write unconditionally (previous hunk), read
conditionally (next hunk). Besides defeating introspection, it also
exposes configuration knobs that don't do anything.
>>
>> ##
>> # @UnixSocketAddress:
>> diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c
>> index 8af0278f15..72527972d5 100644
>> --- a/util/qemu-sockets.c
>> +++ b/util/qemu-sockets.c
>> @@ -206,6 +206,21 @@ static int try_bind(int socket, InetSocketAddress
>> *saddr, struct addrinfo *e)
>> #endif
>> }
>>
>> +static int check_mptcp(const InetSocketAddress *saddr, struct addrinfo *ai,
>> + Error **errp)
>> +{
>> + if (saddr->has_mptcp && saddr->mptcp) {
>> +#ifdef IPPROTO_MPTCP
>> + ai->ai_protocol = IPPROTO_MPTCP;
>> +#else
>> + error_setg(errp, "MPTCP unavailable in this build");
>> + return -1;
>> +#endif
>> + }
>> +
>> + return 0;
>> +}
>> +
>> static int inet_listen_saddr(InetSocketAddress *saddr,
>> int port_offset,
>> int num,
[...]
