On Mon, Mar 02, 2020 at 05:54:42PM +0100, Ján Tomko wrote:
The commit summary is too generic.
How about:
rpc: getaddrinfo: also accept IPv4-mapped IPv6 addresses
On a Monday in 2020, Zhimin Feng wrote:
> If only IPv6 is configured and nscd is started, getaddrinfo
Is ncsd required to reproduce this?
Looking at glibc source:
libvirt passes AI_ADDRCONFIG and if getifaddrs returs only one family,
it is placed into req->ai_family and the code below is hit.
> function reture value is -9. So hints.ai_flags should include
> the AI_V4MAPPED flag.
>
> The following is the partial implementation of getaddrinfo(glibc):
>
> if (req->ai_family == AF_UNSPEC || req->ai_family == AF_INET)
> at->family = AF_INET;
> else if (req->ai_family == AF_INET6 && (req->ai_flags &
AI_V4MAPPED))
> {
> at->addr[3] = at->addr[0];
> at->addr[2] = htonl (0xffff);
> at->addr[1] = 0;
> at->addr[0] = 0;
> at->family = AF_INET6;
> }
> else
> {
> result = -EAI_ADDRFAMILY;
> goto free_and_return;
> }
However small, I'd rather not include GPL code in our commit messages.
Proposed commit message:
If only IPv6 is configured on the host, getaddrinfo with AI_ADDRCONFIG
in hints would return EAI_ADDRFAMILY for nodenames that resolve to IPv4.
Also pass AI_V4MAPPED to accept IPv4-mapped addresses on IPv6-only
systems.
>
> Signed-off-by: Zhimin Feng <fengzhimin1(a)huawei.com>
> ---
> src/rpc/virnetsocket.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/src/rpc/virnetsocket.c b/src/rpc/virnetsocket.c
> index a217404fa6..c547acefc0 100644
> --- a/src/rpc/virnetsocket.c
> +++ b/src/rpc/virnetsocket.c
> @@ -575,7 +575,7 @@ int virNetSocketNewConnectTCP(const char *nodename,
>
> memset(&hints, 0, sizeof(hints));
> hints.ai_family = family;
> - hints.ai_flags = AI_PASSIVE | AI_ADDRCONFIG;
> + hints.ai_flags = AI_PASSIVE | AI_ADDRCONFIG | AI_V4MAPPED;
> hints.ai_socktype = SOCK_STREAM;
>
> int e = getaddrinfo(nodename, service, &hints, &ai);
Reviewed-by: Ján Tomko <jtomko(a)redhat.com>
I noticed that glibc man pages say if ai_flags is 0, then it defaults
to AI_ADDRCONFIG | AI_V4MAPPED. Libvirt had to set ai_flags to get the
AI_PASSIVE flag, and so given that adding AI_V4MAPPED makes sense to
regain the default behaviour we're loosing.
Reviewed-by: Daniel P. Berrangé <berrange(a)redhat.com>
Regards,
Daniel
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