[PATCH v2] mac80211: fix the mesh channel switch support

[PATCH v2] mac80211: fix the mesh channel switch support

[Chun-Yeow Yeoh]

Mesh STA receiving the mesh CSA action frame is not able to trigger
the mesh channel switch due to the incorrect handling and comparison
of mesh channel switch parameters element (MCSP)'s TTL. Make sure
the MCSP's TTL is updated accordingly before calling the
ieee80211_mesh_process_chnswitch.

Signed-off-by: Chun-Yeow Yeoh <yeohchunyeow@gmail.com>
---
v2: only allow channel switch if mesh TTL less than dot11MeshTTL (Chun-Yeow)

 net/mac80211/mesh.c |   11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c
index 896fe3b..98963a4 100644
--- a/net/mac80211/mesh.c
+++ b/net/mac80211/mesh.c
@@ -945,10 +945,8 @@ ieee80211_mesh_process_chnswitch(struct ieee80211_sub_if_data *sdata,
 	params.block_tx = csa_ie.mode & WLAN_EID_CHAN_SWITCH_PARAM_TX_RESTRICT;
 	if (beacon)
 		ifmsh->chsw_ttl = csa_ie.ttl - 1;
-	else
-		ifmsh->chsw_ttl = 0;
 
-	if (ifmsh->chsw_ttl > 0)
+	if (ifmsh->chsw_ttl < ifmsh->mshcfg.dot11MeshTTL)
 		if (ieee80211_mesh_csa_beacon(sdata, &params, false) < 0)
 			return false;
 
@@ -1163,7 +1161,6 @@ static int mesh_fwd_csa_frame(struct ieee80211_sub_if_data *sdata,
 	offset_ttl = (len < 42) ? 7 : 10;
 	*(pos + offset_ttl) -= 1;
 	*(pos + offset_ttl + 1) &= ~WLAN_EID_CHAN_SWITCH_PARAM_INITIATOR;
-	sdata->u.mesh.chsw_ttl = *(pos + offset_ttl);
 
 	memcpy(mgmt_fwd, mgmt, len);
 	eth_broadcast_addr(mgmt_fwd->da);
@@ -1182,7 +1179,7 @@ static void mesh_rx_csa_frame(struct ieee80211_sub_if_data *sdata,
 	u16 pre_value;
 	bool fwd_csa = true;
 	size_t baselen;
-	u8 *pos, ttl;
+	u8 *pos;
 
 	if (mgmt->u.action.u.measurement.action_code !=
 	    WLAN_ACTION_SPCT_CHL_SWITCH)
@@ -1193,8 +1190,8 @@ static void mesh_rx_csa_frame(struct ieee80211_sub_if_data *sdata,
 			   u.action.u.chan_switch.variable);
 	ieee802_11_parse_elems(pos, len - baselen, false, &elems);
 
-	ttl = elems.mesh_chansw_params_ie->mesh_ttl;
-	if (!--ttl)
+	ifmsh->chsw_ttl = elems.mesh_chansw_params_ie->mesh_ttl;
+	if (!--ifmsh->chsw_ttl)
 		fwd_csa = false;
 
 	pre_value = le16_to_cpu(elems.mesh_chansw_params_ie->mesh_pre_value);
-- 
1.7.9.5