From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Sven Eckelmann Date: Tue, 26 May 2015 18:34:27 +0200 Message-Id: <1432658067-14370-2-git-send-email-sven@narfation.org> In-Reply-To: <1432658067-14370-1-git-send-email-sven@narfation.org> References: <1432658067-14370-1-git-send-email-sven@narfation.org> Subject: [B.A.T.M.A.N.] [PATCH 2/2] batman-adv: Avoid u32 overflow during gateway select Reply-To: The list for a Better Approach To Mobile Ad-hoc Networking List-Id: The list for a Better Approach To Mobile Ad-hoc Networking List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: b.a.t.m.a.n@lists.open-mesh.org Cc: Ruben Wisniewsi From: Ruben Wisniewski The gateway selection based on fast connections is using a single value calculated from the average tq (0-255) and the download bandwidth (in 100Kibit). The formula for the first step (tq ** 2 * 10000 * bandwidth) tends to overflow a u32 with low bandwidth settings like 50 [100KiBit] and a tq value of over 92. Changing this to a 64 bit unsigned integer allows to support a bandwidth_down with up to ~2.8e10 [100KiBit] and a perfect tq of 255. This is ~6.6 times higher than the maximum possible value of the gateway announcement TVLV. This problem only affects the non-default gw_sel_class 1. Signed-off-by: Ruben Wisniewsi [sven@narfation.org: rewritten commit message, changed to kernel type] Signed-off-by: Sven Eckelmann --- I am sending this because Ruben Wisniewski didn't fix the commit message (yet) and my earlier patch broke his proposed one. --- net/batman-adv/gateway_client.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c index a404fa7..a145e5a 100644 --- a/net/batman-adv/gateway_client.c +++ b/net/batman-adv/gateway_client.c @@ -153,7 +153,7 @@ batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv) struct batadv_neigh_node *router; struct batadv_neigh_ifinfo *router_ifinfo; struct batadv_gw_node *gw_node, *curr_gw = NULL; - u32 max_gw_factor = 0, tmp_gw_factor = 0; + u64 max_gw_factor = 0, tmp_gw_factor = 0; u32 gw_divisor; u8 max_tq = 0; u8 tq_avg; -- 2.1.4