[libvirt] [PATCH] Disable IPv6 socket auto-binding to IPv4 socket

[Daniel Veillard]

On Wed, Nov 11, 2009 at 05:52:03PM +0000, Daniel P. Berrange wrote:
> Sometimes getaddrinfo returns IPv4 addresses before IPv4 addresses.

  IPv4 addresses before IPv6 if I understand correctly :-)

> IPv6 sockets default to attempting to bind to IPv4 addresses too.
> So if the IPv4 address is activated first, then binding to IPv6
> will fail.
> 
> * daemon/libvirtd.c: Bind to IPv6 and IPv4 addresses separately
> ---
>  daemon/libvirtd.c |   15 +++++++++++++++
>  1 files changed, 15 insertions(+), 0 deletions(-)
> 
> diff --git a/daemon/libvirtd.c b/daemon/libvirtd.c
> index 2fcd9a9..01c9bbc 100644
> --- a/daemon/libvirtd.c
> +++ b/daemon/libvirtd.c
> @@ -615,6 +615,21 @@ remoteMakeSockets (int *fds, int max_fds, int *nfds_r, const char *node, const c
>          int opt = 1;
>          setsockopt (fds[*nfds_r], SOL_SOCKET, SO_REUSEADDR, &opt, sizeof opt);
>  
> +#ifdef IPV6_V6ONLY
> +        if (runp->ai_family == PF_INET6) {
> +            int on = 1;
> +            /*
> +             * Normally on Linux an INET6 socket will bind to the INET4
> +             * address too. If getaddrinfo returns results with INET4
> +             * first though, this will result in INET6 binding failing.
> +             * We can trivially cope with multiple server sockets, so
> +             * we force it to only listen on IPv6
> +             */
> +            setsockopt(fds[*nfds_r], IPPROTO_IPV6,IPV6_V6ONLY,
> +                       (void*)&on, sizeof on);
> +        }
> +#endif
> +
>          if (bind (fds[*nfds_r], runp->ai_addr, runp->ai_addrlen) == -1) {
>              if (errno != EADDRINUSE) {
>                  VIR_ERROR(_("bind: %s"), virStrerror (errno, ebuf, sizeof ebuf));

  ACK,

Daniel

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