Am 03.02.2016 um 18:06 hat Daniel P. Berrange geschrieben: > On Wed, Feb 03, 2016 at 05:33:16PM +0100, Max Reitz wrote: > > We have to introduce a new object (BlockdevOptionsNbd) for several > > reasons: > > - Neither of InetSocketAddress nor UnixSocketAddress alone is > > sufficient, because both are supported > > - We cannot use SocketAddress because NBD does not support an fd, > > and because it is not a flat union which BlockdevOptionsNbd is > > With my patch series that converts NBD to use QIOChannel, all the > entry points for client & server *do* take a SocketAddress struct > to provide address info. So internally the code does in fact allow > use of an FD, if there were a way to specify it a the QAPI level... > > eg see > > https://lists.gnu.org/archive/html/qemu-devel/2016-01/msg04159.html
That's patch 1 of a series that has a few more dependencies. Can the patch be applied without the rest of the series (and without the dependencies) so that we don't have to wait for a very long time with Max's patches? > > - We cannot use a flat union of InetSocketAddress and > > UnixSocketAddress because we would need some kind of discriminator > > which we do not have; we could inline the UnixSocketAddress as a > > string and then make it an 'alternate' type instead of a union, but > > this will not work either, because: > > - InetSocketAddress itself is not suitable for NBD because the port is > > not optional (which it is for NBD) and because it offers more options > > (like choosing between ipv4 and ipv6) which NBD does not support. > > The *should* support ipv4 and ipv6 options for NBD. We should also make > the port optional in the SocketAddress struct - I tried to do that previously > but my patch was flawed, but we should revisit this. > > So IMHO all the things you list above are reasons *for* using SocketAddress > and not re-inventing it poorly with explicit host + port fields. Agreed. Anything in SocketAddress that isn't supported is either a bug or a missing feature. Kevin
