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bug 595: PHY may start receive packet inside SIFS

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This commit is contained in:
Kirill V. Andreev
2009-06-25 15:25:10 +02:00
parent 91530cf31b
commit f2eac3fe7a
2 changed files with 39 additions and 0 deletions
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28
src/devices/wifi/dcf-manager-test.cc
View File

@@ -75,6 +75,8 @@ private:
void ExpectCollision (uint64_t time, uint32_t from, uint32_t nSlots);
void AddRxOkEvt (uint64_t at, uint64_t duration);
void AddRxErrorEvt (uint64_t at, uint64_t duration);
void AddRxInsideSifsEvt (uint64_t at, uint64_t duration);
void AddTxEvt (uint64_t at, uint64_t duration);
void AddNavReset (uint64_t at, uint64_t duration);
void AddNavStart (uint64_t at, uint64_t duration);
void AddAckTimeoutReset (uint64_t at);
@@ -143,6 +145,13 @@ DcfManagerTest::NotifyAccessGranted (uint32_t i)
m_result = result;
}
}
void
DcfManagerTest::AddTxEvt (uint64_t at, uint64_t duration)
{
Simulator::Schedule (MicroSeconds (at) - Now (),
&DcfManager::NotifyTxStartNow, m_dcfManager,
MicroSeconds (duration));
}
void
DcfManagerTest::NotifyInternalCollision (uint32_t i)
{
@@ -244,6 +253,13 @@ DcfManagerTest::AddRxOkEvt (uint64_t at, uint64_t duration)
Simulator::Schedule (MicroSeconds (at+duration) - Now (),
&DcfManager::NotifyRxEndOkNow, m_dcfManager);
}
void
DcfManagerTest::AddRxInsideSifsEvt (uint64_t at, uint64_t duration)
{
Simulator::Schedule (MicroSeconds (at) - Now (),
&DcfManager::NotifyRxStartNow, m_dcfManager,
MicroSeconds (duration));
}
void
DcfManagerTest::AddRxErrorEvt (uint64_t at, uint64_t duration)
{
@@ -321,6 +337,18 @@ DcfManagerTest::RunTests (void)
AddAccessRequest (1, 1, 4, 0);
AddAccessRequest (10, 2, 10, 0);
EndTest ();
// Check that receiving inside SIFS shall be cancelled properly:
// 0 3 4 5 8 9 12 13 14
// | sifs | aifsn | tx | sifs | ack | sifs | aifsn | |tx |
//
StartTest (1, 3, 10);
AddDcfState (1);
AddAccessRequest (1, 1, 4, 0);
AddRxInsideSifsEvt (6, 10);
AddTxEvt(8, 1);
AddAccessRequest (14, 2, 14, 0);
EndTest ();
// The test below mainly intends to test the case where the medium
// becomes busy in the middle of a backoff slot: the backoff counter

11
src/devices/wifi/dcf-manager.cc
View File

@@ -572,6 +572,17 @@ DcfManager::NotifyRxEndErrorNow (void)
void
DcfManager::NotifyTxStartNow (Time duration)
{
if (m_rxing)
{
//this may be caused only if PHY has started to receive a packet
//inside SIFS, so, we check that lastRxStart was maximum a SIFS
//ago
NS_ASSERT(Simulator::Now () - m_lastRxStart < m_sifs);
m_lastRxEnd = Simulator::Now ();
m_lastRxDuration = m_lastRxEnd - m_lastRxStart;
m_lastRxReceivedOk = true;
m_rxing = false;
}
MY_DEBUG ("tx start for "<<duration);
UpdateBackoff ();
m_lastTxStart = Simulator::Now ();