Eric Lee / smarc-fsl-linux-kernel

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Commit 571a963768e7711e0bb5a30f71247b46ec9ca7b9

Authored by Ruben Wisniewski
Committed by Antonio Quartulli
1 parent e071d93eb4

batman-adv: Avoid u32 overflow during gateway select 

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 <ruben@vfn-nrw.de>
[sven@narfation.org: rewritten commit message]
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>

Showing 1 changed file with 1 additions and 1 deletions Side-by-side Diff

net/batman-adv/gateway_client.c
Diff comments   View file @ 571a963
... ... @@ -153,7 +153,7 @@
153 153 struct batadv_neigh_node *router;
154 154 struct batadv_neigh_ifinfo *router_ifinfo;
155 155 struct batadv_gw_node *gw_node, *curr_gw = NULL;
156   - uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
  156 + uint64_t max_gw_factor = 0, tmp_gw_factor = 0;
157 157 uint8_t max_tq = 0;
158 158 uint8_t tq_avg;
159 159 struct batadv_orig_node *orig_node;