Date: Fri, 16 Mar 2018 15:44:49 +0300 From: "Andrey V. Elsukov" <bu7cher@yandex.ru> To: sthaug@nethelp.no, "Alexander V. Chernikov" <melifaro@ipfw.ru> Cc: freebsd-net@freebsd.org Subject: Re: Does FreeBSD do proactive ARP refresh? Message-ID: <21eca372-6fc0-6c86-4ca8-a398bfa37d92@yandex.ru> In-Reply-To: <20180316.124748.104098359.sthaug@nethelp.no> References: <8530131521193098@web19g.yandex.ru> <20180316.110054.74682026.sthaug@nethelp.no> <20180316.122720.71152047.sthaug@nethelp.no> <20180316.124748.104098359.sthaug@nethelp.no>
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From: "Andrey V. Elsukov" <bu7cher@yandex.ru>
To: sthaug@nethelp.no, "Alexander V. Chernikov" <melifaro@ipfw.ru>
Cc: freebsd-net@freebsd.org
Message-ID: <21eca372-6fc0-6c86-4ca8-a398bfa37d92@yandex.ru>
Subject: Re: Does FreeBSD do proactive ARP refresh?
References: <8530131521193098@web19g.yandex.ru>
<20180316.110054.74682026.sthaug@nethelp.no>
<20180316.122720.71152047.sthaug@nethelp.no>
<20180316.124748.104098359.sthaug@nethelp.no>
In-Reply-To: <20180316.124748.104098359.sthaug@nethelp.no>
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On 16.03.2018 14:47, sthaug@nethelp.no wrote:
>> And thank you for that suggestion! The packet loss during ARP refresh
>> (of the destination address connected to the output interface) does
>> *not* happen when the box is forwarding! It only happens with locally
>> generated traffic.
>=20
> Checking once per second with "arp -n <destination IP>" I can see the
> following behavior with net.link.ether.inet.max_age=3D120:
>=20
> - Locally generated traffic: The ARP entry is refreshed after
> net.link.ether.inet.max_age seconds - which presumably means it
> actually expires first. And there is some packet loss.
>=20
> - Transit traffic (the box is forwarding): The ARP entry is refreshed
> 5 seconds *before* net.link.ether.inet.max_age has passed, and there
> is no packet loss.
Can you test this patch? I did not tested it, but I think it should fix
this issue.
--=20
WBR, Andrey V. Elsukov
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Index: sys/net/if_ethersubr.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
--- sys/net/if_ethersubr.c (revision 330791)
+++ sys/net/if_ethersubr.c (working copy)
@@ -317,6 +317,17 @@ ether_output(struct ifnet *ifp, struct mbuf *m,
phdr =3D lle->r_linkdata;
hlen =3D lle->r_hdrlen;
pflags =3D lle->r_flags;
+ /*
+ * XXX: Check if we have feedback request
+ * from arptimer()/nd6_llinfo_timer().
+ */
+ if ((pflags & RLLE_VALID) &&
+ lle->r_skip_req !=3D 0) {
+ LLE_REQ_LOCK(lle);
+ /* Notify that entry was used */
+ lle->r_skip_req =3D 0;
+ LLE_REQ_UNLOCK(lle);
+ }
}
}
}
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