From mboxrd@z Thu Jan 1 00:00:00 1970 From: Erik Kline Subject: [PATCH net-next] Better handling of transition to NUD_PROBE state Date: Mon, 18 May 2015 19:44:41 +0900 Message-ID: <1431945881-14707-1-git-send-email-ek@google.com> Cc: lorenzo@google.com, netdev@vger.kernel.org, davem@davemloft.net, Erik Kline To: hannes@stressinduktion.org Return-path: Received: from mail-pd0-f177.google.com ([209.85.192.177]:34322 "EHLO mail-pd0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752988AbbERKo6 (ORCPT ); Mon, 18 May 2015 06:44:58 -0400 Received: by pdbnk13 with SMTP id nk13so48941956pdb.1 for ; Mon, 18 May 2015 03:44:58 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: [1] When entering NUD_PROBE state via neigh_update(), perhaps received from userspace, correctly (re)initialize the probes count to zero. This is useful for forcing revalidation of a neighbor (for example if the host is attempting to do DNA [IPv4 4436, IPv6 6059]). [2] Notify listeners when a neighbor goes into NUD_PROBE state. By sending notifications on entry to NUD_PROBE state listeners get more timely warnings of imminent connectivity issues. The current notifications on entry to NUD_STALE have somewhat limited usefulness: NUD_STALE is a perfectly normal state, as is NUD_DELAY, whereas notifications on entry to NUD_FAILURE come after a neighbor reachability problem has been confirmed (typically after three probes). Signed-off-by: Erik Kline --- net/core/neighbour.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 3de6542..3a74df7 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -913,6 +913,7 @@ static void neigh_timer_handler(unsigned long arg) neigh->nud_state = NUD_PROBE; neigh->updated = jiffies; atomic_set(&neigh->probes, 0); + notify = 1; next = now + NEIGH_VAR(neigh->parms, RETRANS_TIME); } } else { @@ -1144,6 +1145,8 @@ int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, if (new != old) { neigh_del_timer(neigh); + if (new & NUD_PROBE) + atomic_set(&neigh->probes, 0); if (new & NUD_IN_TIMER) neigh_add_timer(neigh, (jiffies + ((new & NUD_REACHABLE) ? -- 2.2.0.rc0.207.ga3a616c