From: Johannes Berg <johannes.berg@xxxxxxxxx>
If the first frame on a given TID is received with seqno 0 and needed
to be retransmitted, we erroneously drop it because the deduplication
data is initialized to zero, and then comparing
if (unlikely(ieee80211_has_retry(hdr->frame_control) &&
dup_data->last_seq[tid] == hdr->seq_ctrl &&
dup_data->last_sub_frame[tid] >= sub_frame_idx))
return true;
will return in iwl_mvm_is_dup() since last_sub_frame is also set to
zero, and sub_frame_idx is usually zero since this only covers the
relatively rare case of A-MSDU.
Fix this by initializing the last_seq array to 0xffff, which is an
impossible value for hdr->seq_ctrl to have here because the lower
four bits are the fragment number, and fragments aren't handled in
this code but go to mac80211 instead.
Fixes: a571f5f635ef ("iwlwifi: mvm: add duplicate packet detection per rx queue")
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Luca Coelho <luciano.coelho@xxxxxxxxx>
---
drivers/net/wireless/intel/iwlwifi/mvm/sta.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/sta.c b/drivers/net/wireless/intel/iwlwifi/mvm/sta.c
index ee7c978fe5ab..4df5f13fcdae 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/sta.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/sta.c
@@ -1402,11 +1402,24 @@ int iwl_mvm_add_sta(struct iwl_mvm *mvm,
if (iwl_mvm_has_new_rx_api(mvm) &&
!test_bit(IWL_MVM_STATUS_IN_HW_RESTART, &mvm->status)) {
+ int q;
+
dup_data = kcalloc(mvm->trans->num_rx_queues,
- sizeof(*dup_data),
- GFP_KERNEL);
+ sizeof(*dup_data), GFP_KERNEL);
if (!dup_data)
return -ENOMEM;
+ /*
+ * Initialize all the last_seq values to 0xffff which can never
+ * compare equal to the frame's seq_ctrl in the check in
+ * iwl_mvm_is_dup() since the lower 4 bits are the fragment
+ * number and fragmented packets don't reach that function.
+ *
+ * This thus allows receiving a packet with seqno 0 and the
+ * retry bit set as the very first packet on a new TID.
+ */
+ for (q = 0; q < mvm->trans->num_rx_queues; q++)
+ memset(dup_data[q].last_seq, 0xff,
+ sizeof(dup_data[q].last_seq));
mvm_sta->dup_data = dup_data;
}
--
2.11.0
