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References: <cover.1455471945.git.samuel.thibault@ens-lyon.org>
	<043b3b699753317c270087536c8d239aae2432eb.1455471945.git.samuel.thibault@ens-lyon.org>
From: Thomas Huth <thuth@redhat.com>
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Date: Wed, 17 Feb 2016 10:28:26 +0100
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Subject: Re: [Qemu-devel] [PATCHv7 8/9] slirp: Adding IPv6 address for DNS
	relay
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To: Samuel Thibault <samuel.thibault@ens-lyon.org>, qemu-devel@nongnu.org
Cc: zhanghailiang <zhang.zhanghailiang@huawei.com>, Li Zhijian <lizhijian@cn.fujitsu.com>, Stefan Hajnoczi <stefanha@gmail.com>, Jason Wang <jasowang@redhat.com>, Dave Gilbert <dgilbert@redhat.com>, Vasiliy Tolstov <v.tolstov@selfip.ru>, Huangpeng <peter.huangpeng@huawei.com>, Gonglei <arei.gonglei@huawei.com>, Jan Kiszka <jan.kiszka@siemens.com>, Guillaume Subiron <maethor@subiron.org>

On 14.02.2016 18:47, Samuel Thibault wrote:
> From: Guillaume Subiron <maethor@subiron.org>
>=20
> This patch adds an IPv6 address to the DNS relay. in6_equal_dns() is
> developed using this Slirp attribute.
> sotranslate_in/out/accept() are also updated to manage the IPv6 case so=
 the
> guest can be able to join the host using one of the Slirp addresses.
>=20
> For now this only points to localhost. Further development will be need=
ed to
> automatically fetch the IPv6 address from resolv.conf, and announce thi=
s via
> RDNSS.
>=20
> Signed-off-by: Guillaume Subiron <maethor@subiron.org>
> Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
> ---
>  slirp/ip6.h    |  5 ++++-
>  slirp/slirp.c  |  1 +
>  slirp/slirp.h  |  1 +
>  slirp/socket.c | 32 ++++++++++++++++++++++++++++++++
>  4 files changed, 38 insertions(+), 1 deletion(-)
>=20
> diff --git a/slirp/ip6.h b/slirp/ip6.h
> index 9f7623f..ded6d78 100644
> --- a/slirp/ip6.h
> +++ b/slirp/ip6.h
> @@ -70,7 +70,10 @@ static inline bool in6_equal_mach(const struct in6_a=
ddr *a,
>    || (in6_equal_net(a, &(struct in6_addr)LINKLOCAL_ADDR, 64)\
>        && in6_equal_mach(a, &slirp->vhost_addr6, 64)))
> =20
> -#define in6_equal_dns(a) 0
> +#define in6_equal_dns(a)\
> +    ((in6_equal_net(a, &slirp->vprefix_addr6, slirp->vprefix_len)\
> +     || in6_equal_net(a, &(struct in6_addr)LINKLOCAL_ADDR, 64))\
> +     && in6_equal_mach(a, &slirp->vnameserver_addr6, slirp->vprefix_le=
n))

Does this work properly if vprefix_len < 64 ? I think this rather should
be done similar to in6_equal_router(), i.e. something like:

#define in6_equal_dns(a)\
    ((in6_equal_net(a, &slirp->vprefix_addr6, slirp->vprefix_len) && \
      in6_equal_mach(a, &slirp->vnameserver_addr6, slirp->vprefix_len)) \
    || (in6_equal_net(a, &(struct in6_addr)LINKLOCAL_ADDR, 64)) && \
        in6_equal_mach(a, &slirp->vnameserver_addr6, 64))

?

 Thomas