From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Antonio Quartulli Date: Fri, 14 Aug 2015 22:57:06 +0200 Message-Id: <1439585834-26564-3-git-send-email-antonio@meshcoding.com> In-Reply-To: <1439585834-26564-1-git-send-email-antonio@meshcoding.com> References: <1439585834-26564-1-git-send-email-antonio@meshcoding.com> Subject: [B.A.T.M.A.N.] [PATCH 02/10] batman-adv: Avoid u32 overflow during gateway select List-Id: The list for a Better Approach To Mobile Ad-hoc Networking List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: davem@davemloft.net Cc: Ruben Wisniewsi , Marek Lindner , netdev@vger.kernel.org, b.a.t.m.a.n@lists.open-mesh.org, Antonio Quartulli 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] Signed-off-by: Sven Eckelmann Signed-off-by: Marek Lindner Signed-off-by: Antonio Quartulli --- 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 e1e1f31..4ac24d8 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; - uint32_t max_gw_factor = 0, tmp_gw_factor = 0; + uint64_t max_gw_factor = 0, tmp_gw_factor = 0; uint8_t max_tq = 0; uint8_t tq_avg; struct batadv_orig_node *orig_node; -- 2.5.0