Hi,
On Wed, Nov 06, 2013 at 04:43:54AM -0500, Pietro Paolini wrote:
> > So you want "IPv4 in IPv6, and you want to see fragmentation on the IPv6
> > packets".
>
> > What happens if you put the tun1 mtu to 1500?
>
> In that case it does not fragment the IPv4 packet but the whole packet is
> discarded in this piece of code:
> mtu = dst_mtu(dst) - sizeof (*ipv6h);
> if (skb->len > mtu) { --> 1496 > 1460 <--
> *pmtu = mtu;
> err = -EMSGSIZE;
> goto tx_err_dst_release;
> }
>
Interesting. So Linux doesn't handle this as "an IPv6 packet created
by myself, following the normal rules for packets sourced locally =
fragment if needed", but follows shortcuts.
> which is in the ip6_tnl_xmit2() placed in ip6_tunnel.c, I am assuming this
> borderline case is not handled by the kernel (!) then any ideas regarding how
> to solve this issues ?
I have to pass here, sorry, no idea. I don't know these areas well enough
to understand what would be needed here.
As a workaround, you could use iptables to lower TCP MSS side on the IPv4
packets, to avoid having full-sized packets on the IPv4 side -> no need
for IPv6 fragmentation. But that will not help UDP or other IP protocols.
Or accept IPv4 fragmentation...
gert
--
USENET is *not* the non-clickable part of WWW!
//www.muc.de/~gert/
Gert Doering - Munich, Germany g...@greenie.muc.de
fax: +49-89-35655025 g...@net.informatik.tu-muenchen.de
pgpt5agSZn1rv.pgp
Description: PGP signature
_______________________________________________ openwrt-devel mailing list openwrt-devel@lists.openwrt.org https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
