mac80211: process the CSA frame for mesh accordingly
Process the CSA frame according to the procedures define in IEEE Std
802.11-2012 section 10.9.8.4.3 as follow:
* The mesh channel switch parameters element (MCSP) must be availabe.
* If the MCSP's TTL is 1, drop the frame but still process the CSA.
* If the MCSP's precedence value is less than or equal to the current
precedence value, drop the frame and do not process the CSA.
* The CSA frame is forwarded after TTL is decremented by 1 and the
initiator field is set to 0. Transmit restrict field and others
are maintained as is.
* No beacon or probe response frame are handled here.
Also, introduce the debug message used for mesh CSA purpose.
Signed-off-by: Chun-Yeow Yeoh <yeohchunyeow@cozybit.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c
index 707ac61..0a3ccaa 100644
--- a/net/mac80211/mesh.c
+++ b/net/mac80211/mesh.c
@@ -920,6 +920,82 @@
stype, mgmt, &elems, rx_status);
}
+static int mesh_fwd_csa_frame(struct ieee80211_sub_if_data *sdata,
+ struct ieee80211_mgmt *mgmt, size_t len)
+{
+ struct ieee80211_mgmt *mgmt_fwd;
+ struct sk_buff *skb;
+ struct ieee80211_local *local = sdata->local;
+ u8 *pos = mgmt->u.action.u.chan_switch.variable;
+ size_t offset_ttl;
+
+ skb = dev_alloc_skb(local->tx_headroom + len);
+ if (!skb)
+ return -ENOMEM;
+ skb_reserve(skb, local->tx_headroom);
+ mgmt_fwd = (struct ieee80211_mgmt *) skb_put(skb, len);
+
+ /* offset_ttl is based on whether the secondary channel
+ * offset is available or not. Substract 1 from the mesh TTL
+ * and disable the initiator flag before forwarding.
+ */
+ offset_ttl = (len < 42) ? 7 : 10;
+ *(pos + offset_ttl) -= 1;
+ *(pos + offset_ttl + 1) &= ~WLAN_EID_CHAN_SWITCH_PARAM_INITIATOR;
+
+ memcpy(mgmt_fwd, mgmt, len);
+ eth_broadcast_addr(mgmt_fwd->da);
+ memcpy(mgmt_fwd->sa, sdata->vif.addr, ETH_ALEN);
+ memcpy(mgmt_fwd->bssid, sdata->vif.addr, ETH_ALEN);
+
+ ieee80211_tx_skb(sdata, skb);
+ return 0;
+}
+
+static void mesh_rx_csa_frame(struct ieee80211_sub_if_data *sdata,
+ struct ieee80211_mgmt *mgmt, size_t len)
+{
+ struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
+ struct ieee802_11_elems elems;
+ u16 pre_value;
+ bool block_tx, fwd_csa = true;
+ size_t baselen;
+ u8 *pos, ttl;
+
+ if (mgmt->u.action.u.measurement.action_code !=
+ WLAN_ACTION_SPCT_CHL_SWITCH)
+ return;
+
+ pos = mgmt->u.action.u.chan_switch.variable;
+ baselen = offsetof(struct ieee80211_mgmt,
+ 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)
+ fwd_csa = false;
+
+ pre_value = le16_to_cpu(elems.mesh_chansw_params_ie->mesh_pre_value);
+ if (ifmsh->pre_value >= pre_value)
+ return;
+
+ ifmsh->pre_value = pre_value;
+
+ /* forward or re-broadcast the CSA frame */
+ if (fwd_csa) {
+ if (mesh_fwd_csa_frame(sdata, mgmt, len) < 0)
+ mcsa_dbg(sdata, "Failed to forward the CSA frame");
+ }
+
+ /* block the Tx only after forwarding the CSA frame if required */
+ block_tx = elems.mesh_chansw_params_ie->mesh_flags &
+ WLAN_EID_CHAN_SWITCH_PARAM_TX_RESTRICT;
+ if (block_tx)
+ ieee80211_stop_queues_by_reason(&sdata->local->hw,
+ IEEE80211_MAX_QUEUE_MAP,
+ IEEE80211_QUEUE_STOP_REASON_CSA);
+}
+
static void ieee80211_mesh_rx_mgmt_action(struct ieee80211_sub_if_data *sdata,
struct ieee80211_mgmt *mgmt,
size_t len,
@@ -939,6 +1015,9 @@
if (mesh_action_is_path_sel(mgmt))
mesh_rx_path_sel_frame(sdata, mgmt, len);
break;
+ case WLAN_CATEGORY_SPECTRUM_MGMT:
+ mesh_rx_csa_frame(sdata, mgmt, len);
+ break;
}
}
@@ -1056,13 +1135,11 @@
(unsigned long) sdata);
ifmsh->accepting_plinks = true;
- ifmsh->preq_id = 0;
- ifmsh->sn = 0;
- ifmsh->num_gates = 0;
atomic_set(&ifmsh->mpaths, 0);
mesh_rmc_init(sdata);
ifmsh->last_preq = jiffies;
ifmsh->next_perr = jiffies;
+ ifmsh->chsw_init = false;
/* Allocate all mesh structures when creating the first mesh interface. */
if (!mesh_allocated)
ieee80211s_init();