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iwlwifi: mvm: ignore stale TDLS ch-switch responses

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During out-of-channel activities (e.g. scan) TDLS ch-switch responses from
a peer are kept in FW. These packets arrive only after the out-of-channel
activity is complete, which can be in the order of several seconds.

Since TDLS ch-sw has no dialog-token-like mechanism for distinguishing
sessions, use the GP2 time of the incoming ch-switch response to discern
validity. For this purpose record the GP2 time of an outgoing TDLS ch-sw
request and compare to the Rx time of the ch-sw response.
The methods works in practice since the GP2 time of FW-deferred Rx is
accurate and contains the real Rx timestamp.

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>
This commit is contained in:
Arik Nemtsov 2015-01-22 14:24:44 +02:00 committed by Emmanuel Grumbach
parent 5cb1270143
commit b9dccdb33c
2 changed files with 16 additions and 2 deletions
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3
drivers/net/wireless/iwlwifi/mvm/mvm.h
View File

@ -798,6 +798,9 @@ struct iwl_mvm {
struct cfg80211_chan_def chandef;
struct sk_buff *skb; /* ch sw template */
u32 ch_sw_tm_ie;
/* timestamp of last ch-sw request sent (GP2 time) */
u32 sent_timestamp;
} peer;
} tdls_cs;

15
drivers/net/wireless/iwlwifi/mvm/tdls.c
View File

@ -64,6 +64,8 @@
#include <linux/etherdevice.h>
#include "mvm.h"
#include "time-event.h"
#include "iwl-io.h"
#include "iwl-prph.h"
#define TU_TO_US(x) (x * 1024)
#define TU_TO_MS(x) (TU_TO_US(x) / 1000)
@ -250,6 +252,11 @@ static void iwl_mvm_tdls_update_cs_state(struct iwl_mvm *mvm,
iwl_mvm_tdls_cs_state_str(state));
mvm->tdls_cs.state = state;
/* we only send requests to our switching peer - update sent time */
if (state == IWL_MVM_TDLS_SW_REQ_SENT)
mvm->tdls_cs.peer.sent_timestamp =
iwl_read_prph(mvm->trans, DEVICE_SYSTEM_TIME_REG);
if (state == IWL_MVM_TDLS_SW_IDLE)
mvm->tdls_cs.cur_sta_id = IWL_MVM_STATION_COUNT;
}
@ -302,7 +309,7 @@ out:
static int
iwl_mvm_tdls_check_action(struct iwl_mvm *mvm,
enum iwl_tdls_channel_switch_type type,
const u8 *peer, bool peer_initiator)
const u8 *peer, bool peer_initiator, u32 timestamp)
{
bool same_peer = false;
int ret = 0;
@ -341,6 +348,9 @@ iwl_mvm_tdls_check_action(struct iwl_mvm *mvm,
else if (type == TDLS_SEND_CHAN_SW_REQ)
/* wait for idle before sending another request */
ret = -EBUSY;
else if (timestamp <= mvm->tdls_cs.peer.sent_timestamp)
/* we got a stale response - ignore it */
ret = -EINVAL;
break;
case IWL_MVM_TDLS_SW_RESP_RCVD:
/*
@ -399,7 +409,8 @@ iwl_mvm_tdls_config_channel_switch(struct iwl_mvm *mvm,
lockdep_assert_held(&mvm->mutex);
ret = iwl_mvm_tdls_check_action(mvm, type, peer, peer_initiator);
ret = iwl_mvm_tdls_check_action(mvm, type, peer, peer_initiator,
timestamp);
if (ret)
return ret;