iwlwifi: mvm: capture the FCS in monitor mode

This can be useful when using the device as a sniffer.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

2 files changed, 12 insertions, 2 deletions

diff --git a/drivers/net/wireless/iwlwifi/mvm/mac-ctxt.c b/drivers/net/wireless/iwlwifi/mvm/mac-ctxt.c
index ab5a7ac90dcd..f41f9b079831 100644
--- a/drivers/net/wireless/iwlwifi/mvm/mac-ctxt.c
+++ b/drivers/net/wireless/iwlwifi/mvm/mac-ctxt.c
@@ -719,7 +719,9 @@ static int iwl_mvm_mac_ctxt_cmd_listener(struct iwl_mvm *mvm,
         cmd.filter_flags = cpu_to_le32(MAC_FILTER_IN_PROMISC |
                                        MAC_FILTER_IN_CONTROL_AND_MGMT |
                                        MAC_FILTER_IN_BEACON |
-                                       MAC_FILTER_IN_PROBE_REQUEST);
+                                       MAC_FILTER_IN_PROBE_REQUEST |
+                                       MAC_FILTER_IN_CRC32);
+        mvm->hw->flags |= IEEE80211_HW_RX_INCLUDES_FCS;
 
         return iwl_mvm_mac_ctxt_send_cmd(mvm, &cmd);
 }
@@ -1122,6 +1124,10 @@ int iwl_mvm_mac_ctxt_remove(struct iwl_mvm *mvm, struct ieee80211_vif *vif)
         }
 
         mvmvif->uploaded = false;
+
+        if (vif->type == NL80211_IFTYPE_MONITOR)
+                mvm->hw->flags &= ~IEEE80211_HW_RX_INCLUDES_FCS;
+
         return 0;
 }
 
diff --git a/drivers/net/wireless/iwlwifi/mvm/rx.c b/drivers/net/wireless/iwlwifi/mvm/rx.c
index a4af5019a496..3a1f3982109d 100644
--- a/drivers/net/wireless/iwlwifi/mvm/rx.c
+++ b/drivers/net/wireless/iwlwifi/mvm/rx.c
@@ -300,10 +300,14 @@ int iwl_mvm_rx_rx_mpdu(struct iwl_mvm *mvm, struct iwl_rx_cmd_buffer *rxb,
                 return 0;
         }
 
+        /*
+         * Keep packets with CRC errors (and with overrun) for monitor mode
+         * (otherwise the firmware discards them) but mark them as bad.
+         */
         if (!(rx_pkt_status & RX_MPDU_RES_STATUS_CRC_OK) ||
             !(rx_pkt_status & RX_MPDU_RES_STATUS_OVERRUN_OK)) {
                 IWL_DEBUG_RX(mvm, "Bad CRC or FIFO: 0x%08X.\n", rx_pkt_status);
-                return 0;
+                rx_status.flag |= RX_FLAG_FAILED_FCS_CRC;
         }
 
         /* This will be used in several places later */