[Qemu-devel] Patch to improve handling of server sockets

[Reinhard Max]

Hi,

I am maintaining the tightvnc package for openSUSE and was recently 
confronted with an alleged vnc problem with QWMU that turned out to be 
a shortcoming in QEMU's code for handling TCP server sockets, which is 
used by the vnc and char modules.

The problem occurs when the address to listen on is given as a name 
which resolves to multiple IP addresses the most prominent example 
being "localhost" resolving to 127.0.0.1 and ::1 .

The existing code stopped walking the list of addresses returned by 
getaddrinfo() as soon as one socket was successfully opened and bound. 
The result was that a qemu instance started with "-vnc localhost:42" 
only listened on ::1, wasn't reachable through 127.0.0.1. The fact 
that the code set the IPV6_V6ONLY socket option didn't help, because 
that option only works when the socket gets bound to the IPv6 wildcard 
address (::), but is useless for explicit address bindings.

The attached patch against QEMU 0.11.0 extends inet_listen() to create 
sockets for as many addresses from the address list as possible and 
adapts its callers and their data structures to deal with a linked 
list of socket FDs rather than a single file descriptor.

So far I've only done some testing with the -vnc option. More testing 
is needed in the qemu-char area and for the parts of the code that get 
triggered from QEMU's Monitor.


Please review and comment.


cu
        Reinhard

P.S. Please keep me in Cc when replying.

0034-qemu-multiple-sockets.patch
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