Julian Anastasov <j...@ssi.bg> wrote:
> On Mon, 20 Jul 2015, Florian Westphal wrote:
> > The VM has two interfaces,
> > eth0, 192.168.7.10
> > eth1, 192.168.8.10
> >
> > ip route del default
> > ip route add tos 0x0 via 192.168.7.1
> > ip route add tos 0x10 via 192.168.8.2
> >
> > 7.1 is reachable via eth0 (7.10/24)
> > 8.2 *should* be rechable via eth1 (8.10/24)
> >
> > I say *should* because I deliberately deleted this address from gateway
> > connected to that interface.
> >
> > Now, I run
> >
> > ping -Q 0x10 192.168.0.7
> >
> > Packets get sent via tos 0x0. So far, so good.
> >
> > Now I add back 192.168.8.2.
> >
> > But no probe takes place so packets continue to be sent via tos 0 route.
> >
> > neigh_lookup returns NULL -> state is NUD_NONE -> gw is deemed unreachable
>
> So, this is a case when configuration changes,
> for example, simple change in list of routes is not noticed?
There are no changes on the test system, the address 192.168.8.2 is
added back to the gateway only.
> May be we can just play with the state as already
> discussed? Example separate diff (to be ported for net-next).
>
> ipv4: be more aggressive when probing alternative gateways
>
> Currently, we do not notice if new alternative gateways
> are added. We can do it by checking for present neigh
> entry. Also, gateways that are currently probed (NUD_INCOMPLETE)
> can be skipped from round-robin probing.
> diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
> index c7358ea..cd1732a 100644
> --- a/net/ipv4/fib_semantics.c
> +++ b/net/ipv4/fib_semantics.c
> @@ -421,13 +421,15 @@ static int fib_detect_death(struct fib_info *fi, int
> order,
> if (n) {
> state = n->nud_state;
> neigh_release(n);
> + } else {
> + return 0;
> }
> if (state == NUD_REACHABLE)
> return 0;
> if ((state & NUD_VALID) && order != dflt)
> return 0;
> if ((state & NUD_VALID) ||
> - (*last_idx < 0 && order > dflt)) {
> + (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
> *last_resort = fi;
> *last_idx = order;
> }
I think its a good idea.
Could you please submit your two patches (tos fix and this one)
formally?
Thanks!
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