mac80211: mesh: fix HWMP sequence numbering to follow standard

[ Upstream commit 1f631c3201fe5491808df143d8fcba81b3197ffd ]

IEEE 802.11-2016 14.10.8.3 HWMP sequence numbering says:
If it is a target mesh STA, it shall update its own HWMP SN to
maximum (current HWMP SN, target HWMP SN in the PREQ element) + 1
immediately before it generates a PREP element in response to a
PREQ element.

Signed-off-by: Yuan-Chi Pang <fu3mo6goo@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/mac80211/mesh_hwmp.c b/net/mac80211/mesh_hwmp.c
index fed598a202c8996a6ef22a909318c0ae70ea5939..b0acb2961e805df66dcc6a3be80c929f6bd21649 100644 (file)
--- a/net/mac80211/mesh_hwmp.c
+++ b/net/mac80211/mesh_hwmp.c
@@ -563,6 +563,10 @@ static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
                forward = false;
                reply = true;
                target_metric = 0;
+
+               if (SN_GT(target_sn, ifmsh->sn))
+                       ifmsh->sn = target_sn;
+
                if (time_after(jiffies, ifmsh->last_sn_update +
                                        net_traversal_jiffies(sdata)) ||
                    time_before(jiffies, ifmsh->last_sn_update)) {