iwlwifi: mvm: improve TDLS ch-sw state machine

Add a response-received state and add more limits on allowed requests
in each state of the connection. Previously ch-switch requests from
other peers could interrupt an outgoing active ch-switch. Also stale
packets from the current peer could disrupt the channel switch state.

Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

diff --git a/drivers/net/wireless/iwlwifi/mvm/mvm.h b/drivers/net/wireless/iwlwifi/mvm/mvm.h
index 7773ffc..fc80b7b 100644 (file)
--- a/drivers/net/wireless/iwlwifi/mvm/mvm.h
+++ b/drivers/net/wireless/iwlwifi/mvm/mvm.h
@@ -532,6 +532,7 @@ enum {
 enum iwl_mvm_tdls_cs_state {
        IWL_MVM_TDLS_SW_IDLE = 0,
        IWL_MVM_TDLS_SW_REQ_SENT,
+       IWL_MVM_TDLS_SW_RESP_RCVD,
        IWL_MVM_TDLS_SW_REQ_RCVD,
        IWL_MVM_TDLS_SW_ACTIVE,
 };

diff --git a/drivers/net/wireless/iwlwifi/mvm/tdls.c b/drivers/net/wireless/iwlwifi/mvm/tdls.c
index c0e00ba..ea1831c 100644 (file)
--- a/drivers/net/wireless/iwlwifi/mvm/tdls.c
+++ b/drivers/net/wireless/iwlwifi/mvm/tdls.c
@@ -228,6 +228,8 @@ iwl_mvm_tdls_cs_state_str(enum iwl_mvm_tdls_cs_state state)
                return "IDLE";
        case IWL_MVM_TDLS_SW_REQ_SENT:
                return "REQ SENT";
+       case IWL_MVM_TDLS_SW_RESP_RCVD:
+               return "RESP RECEIVED";
        case IWL_MVM_TDLS_SW_REQ_RCVD:
                return "REQ RECEIVED";
        case IWL_MVM_TDLS_SW_ACTIVE:
@@ -325,17 +327,27 @@ iwl_mvm_tdls_check_action(struct iwl_mvm *mvm,
                        ret = -EINVAL;
                break;
        case IWL_MVM_TDLS_SW_REQ_SENT:
+               /* only allow requests from the same peer */
+               if (!same_peer)
+                       ret = -EBUSY;
+               else if (type == TDLS_SEND_CHAN_SW_RESP_AND_MOVE_CH &&
+                        !peer_initiator)
+                       /*
+                        * We received a ch-switch request while an outgoing
+                        * one is pending. Allow it if the peer is the link
+                        * initiator.
+                        */
+                       ret = -EBUSY;
+               else if (type == TDLS_SEND_CHAN_SW_REQ)
+                       /* wait for idle before sending another request */
+                       ret = -EBUSY;
+               break;
+       case IWL_MVM_TDLS_SW_RESP_RCVD:
                /*
-                * We received a ch-switch request while an outgoing one is
-                * pending. Allow it to proceed if the other peer is the same
-                * one we sent to, and we are not the link initiator.
+                * we are waiting for the FW to give an "active" notification,
+                * so ignore requests in the meantime
                 */
-               if (type == TDLS_SEND_CHAN_SW_RESP_AND_MOVE_CH) {
-                       if (!same_peer)
-                               ret = -EBUSY;
-                       else if (!peer_initiator) /* we are the initiator */
-                               ret = -EBUSY;
-               }
+               ret = -EBUSY;
                break;
        case IWL_MVM_TDLS_SW_REQ_RCVD:
                /* as above, allow the link initiator to proceed */
@@ -349,9 +361,12 @@ iwl_mvm_tdls_check_action(struct iwl_mvm *mvm,
                }
                break;
        case IWL_MVM_TDLS_SW_ACTIVE:
-               /* we don't allow initiations during active channel switch */
-               if (type == TDLS_SEND_CHAN_SW_REQ)
-                       ret = -EINVAL;
+               /*
+                * the only valid request when active is a request to return
+                * to the base channel by the current off-channel peer
+                */
+               if (type != TDLS_MOVE_CH || !same_peer)
+                       ret = -EBUSY;
                break;
        }
 
@@ -473,6 +488,8 @@ iwl_mvm_tdls_config_channel_switch(struct iwl_mvm *mvm,
                                             type == TDLS_SEND_CHAN_SW_REQ ?
                                             IWL_MVM_TDLS_SW_REQ_SENT :
                                             IWL_MVM_TDLS_SW_REQ_RCVD);
+       } else {
+               iwl_mvm_tdls_update_cs_state(mvm, IWL_MVM_TDLS_SW_RESP_RCVD);
        }
 
 out:
@@ -657,12 +674,15 @@ iwl_mvm_tdls_recv_channel_switch(struct ieee80211_hw *hw,
        struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
        enum iwl_tdls_channel_switch_type type;
        unsigned int delay;
+       const char *action_str =
+               params->action_code == WLAN_TDLS_CHANNEL_SWITCH_REQUEST ?
+               "REQ" : "RESP";
 
        mutex_lock(&mvm->mutex);
 
        IWL_DEBUG_TDLS(mvm,
-                      "Received TDLS ch switch action %d from %pM status %d\n",
-                      params->action_code, params->sta->addr, params->status);
+                      "Received TDLS ch switch action %s from %pM status %d\n",
+                      action_str, params->sta->addr, params->status);
 
        /*
         * we got a non-zero status from a peer we were switching to - move to