mac802154: rx: add software checksum filtering check

This patch adds a new hardware flag which indicate that the transceiver
doesn't support check for bad checksum via hardware. Also add a handling of
this while receive.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

2 files changed, 15 insertions, 2 deletions

diff --git a/include/net/mac802154.h b/include/net/mac802154.h
index bc1d40c826e3..8f1de6844cb0 100644
--- a/include/net/mac802154.h
+++ b/include/net/mac802154.h
@@ -96,6 +96,8 @@ struct ieee802154_hw {
 #define IEEE802154_HW_PROMISCUOUS       0x00000200
 /* Indicates that receiver omits FCS. */
 #define IEEE802154_HW_RX_OMIT_CKSUM     0x00000400
+/* Indicates that receiver will not filter frames with bad checksum. */
+#define IEEE802154_HW_RX_DROP_BAD_CKSUM 0x00000800
 
 /* Indicates that receiver omits FCS and xmitter will add FCS on it's own. */
 #define IEEE802154_HW_OMIT_CKSUM        (IEEE802154_HW_TX_OMIT_CKSUM | \
diff --git a/net/mac802154/rx.c b/net/mac802154/rx.c
index b6a4bbfdbf90..c9f1c72a1afc 100644
--- a/net/mac802154/rx.c
+++ b/net/mac802154/rx.c
@@ -248,6 +248,7 @@ ieee802154_monitors_rx(struct ieee802154_local *local, struct sk_buff *skb)
 void ieee802154_rx(struct ieee802154_hw *hw, struct sk_buff *skb)
 {
         struct ieee802154_local *local = hw_to_local(hw);
+        u16 crc;
 
         WARN_ON_ONCE(softirq_count() == 0);
 
@@ -256,8 +257,7 @@ void ieee802154_rx(struct ieee802154_hw *hw, struct sk_buff *skb)
          * solution because the monitor needs a crc here.
          */
         if (local->hw.flags & IEEE802154_HW_RX_OMIT_CKSUM) {
-                u16 crc = crc_ccitt(0, skb->data, skb->len);
-
+                crc = crc_ccitt(0, skb->data, skb->len);
                 put_unaligned_le16(crc, skb_put(skb, 2));
         }
 
@@ -265,6 +265,17 @@ void ieee802154_rx(struct ieee802154_hw *hw, struct sk_buff *skb)
 
         ieee802154_monitors_rx(local, skb);
 
+        /* Check if transceiver doesn't validate the checksum.
+         * If not we validate the checksum here.
+         */
+        if (local->hw.flags & IEEE802154_HW_RX_DROP_BAD_CKSUM) {
+                crc = crc_ccitt(0, skb->data, skb->len);
+                if (crc) {
+                        rcu_read_unlock();
+                        kfree_skb(skb);
+                        return;
+                }
+        }
         /* remove crc */
         skb_trim(skb, skb->len - 2);