netdev - [PATCH 4/4] batman-adv: request the full table if tt

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Date:	Fri,  8 Jul 2011 00:35:46 +0200
From:	Marek Lindner <lindner_marek@...oo.de>
To:	davem@...emloft.net
Cc:	netdev@...r.kernel.org, b.a.t.m.a.n@...ts.open-mesh.org,
	Antonio Quartulli <ordex@...istici.org>,
	Marek Lindner <lindner_marek@...oo.de>
Subject: [PATCH 4/4] batman-adv: request the full table if tt_crc doesn't match

From: Antonio Quartulli <ordex@...istici.org>

In case of tt_crc mismatching for a certain orig_node after applying the
changes, the node must request the full table immediately.

Signed-off-by: Antonio Quartulli <ordex@...istici.org>
Signed-off-by: Marek Lindner <lindner_marek@...oo.de>
---
 net/batman-adv/routing.c |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index 2cb98be..0f32c81 100644
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -91,6 +91,18 @@ static void update_transtable(struct bat_priv *bat_priv,
 		 * to recompute it to spot any possible inconsistency
 		 * in the global table */
 		orig_node->tt_crc = tt_global_crc(bat_priv, orig_node);
+
+		/* The ttvn alone is not enough to guarantee consistency
+		 * because a single value could repesent different states
+		 * (due to the wrap around). Thus a node has to check whether
+		 * the resulting table (after applying the changes) is still
+		 * consistent or not. E.g. a node could disconnect while its
+		 * ttvn is X and reconnect on ttvn = X + TTVN_MAX: in this case
+		 * checking the CRC value is mandatory to detect the
+		 * inconsistency */
+		if (orig_node->tt_crc != tt_crc)
+			goto request_table;
+
 		/* Roaming phase is over: tables are in sync again. I can
 		 * unset the flag */
 		orig_node->tt_poss_change = false;
-- 
1.7.5.3

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