batman-adv/patches/0001-batman-adv-Avoid-u32-overflow-during-gateway-select.patch

   1 From f63c54bba31d2c86269982fd8efdfb618f1daabe Mon Sep 17 00:00:00 2001
   2 From: Ruben Wisniewski <ruben@freifunk-nrw.de>
   3 Date: Tue, 26 May 2015 18:34:27 +0200
   4 Subject: [PATCH 01/17] batman-adv: Avoid u32 overflow during gateway select
   5
   6 The gateway selection based on fast connections is using a single value
   7 calculated from the average tq (0-255) and the download bandwidth (in
   8 100Kibit). The formula for the first step (tq ** 2 * 10000 * bandwidth)
   9 tends to overflow a u32 with low bandwidth settings like 50 [100KiBit]
  10 and a tq value of over 92.
  11
  12 Changing this to a 64 bit unsigned integer allows to support a
  13 bandwidth_down with up to ~2.8e10 [100KiBit] and a perfect tq of 255. This
  14 is ~6.6 times higher than the maximum possible value of the gateway
  15 announcement TVLV.
  16
  17 This problem only affects the non-default gw_sel_class 1.
  18
  19 Signed-off-by: Ruben Wisniewsi <ruben@vfn-nrw.de>
  20 [sven@narfation.org: rewritten commit message, changed to kernel type]
  21 Signed-off-by: Sven Eckelmann <sven@narfation.org>
  22 Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
  23 ---
  24  gateway_client.c | 2 +-
  25  1 file changed, 1 insertion(+), 1 deletion(-)
  26
  27 diff --git a/gateway_client.c b/gateway_client.c
  28 index a85eaca..3f32357 100644
  29 --- a/gateway_client.c
  30 +++ b/gateway_client.c
  31 @@ -133,7 +133,7 @@ batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv)
  32         struct batadv_neigh_node *router;
  33         struct batadv_neigh_ifinfo *router_ifinfo;
  34         struct batadv_gw_node *gw_node, *curr_gw = NULL;
  35 -       uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
  36 +       uint64_t max_gw_factor = 0, tmp_gw_factor = 0;
  37         uint32_t gw_divisor;
  38         uint8_t max_tq = 0;
  39         uint8_t tq_avg;
  40 --
  41 2.1.4
  42