This patch change the actual crc handling while receive. Currently the
IEEE802154_HW_RX_OMIT_CKSUM flag is used to filter a frame with a bad crc.
This patch changes the behaviour of IEEE802154_HW_RX_OMIT_CKSUM to add a
crc while receiving for the monitor interface. After monitor receiving
we remove the crc for frame parsing. This affect the driver layer
because all drivers sets IEEE802154_HW_RX_OMIT_CKSUM and deliver without
checksum.
Signed-off-by: Alexander Aring <alex.aring@xxxxxxxxx>
---
net/mac802154/rx.c | 34 ++++++++++++----------------------
1 file changed, 12 insertions(+), 22 deletions(-)
diff --git a/net/mac802154/rx.c b/net/mac802154/rx.c
index 51a55d9..b6a4bbf 100644
--- a/net/mac802154/rx.c
+++ b/net/mac802154/rx.c
@@ -21,6 +21,7 @@
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/crc-ccitt.h>
+#include <asm/unaligned.h>
#include <net/mac802154.h>
#include <net/ieee802154_netdev.h>
@@ -225,8 +226,6 @@ ieee802154_monitors_rx(struct ieee802154_local *local, struct sk_buff *skb)
{
struct sk_buff *skb2;
struct ieee802154_sub_if_data *sdata;
- u16 crc = crc_ccitt(0, skb->data, skb->len);
- u8 *data;
skb_reset_mac_header(skb);
skb->ip_summed = CHECKSUM_UNNECESSARY;
@@ -241,9 +240,6 @@ ieee802154_monitors_rx(struct ieee802154_local *local, struct sk_buff *skb)
skb2 = skb_clone(skb, GFP_ATOMIC);
skb2->dev = sdata->dev;
skb2->pkt_type = PACKET_HOST;
- data = skb_put(skb2, 2);
- data[0] = crc & 0xff;
- data[1] = crc >> 8;
netif_rx_ni(skb2);
}
@@ -255,32 +251,26 @@ void ieee802154_rx(struct ieee802154_hw *hw, struct sk_buff *skb)
WARN_ON_ONCE(softirq_count() == 0);
- if (!(local->hw.flags & IEEE802154_HW_RX_OMIT_CKSUM)) {
- u16 crc;
+ /* TODO: When a transceiver omits the checksum here, we
+ * add an own calculated one. This is currently an ugly
+ * 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);
- if (skb->len < 2) {
- pr_debug("got invalid frame\n");
- goto fail;
- }
- crc = crc_ccitt(0, skb->data, skb->len);
- if (crc) {
- pr_debug("CRC mismatch\n");
- goto fail;
- }
- skb_trim(skb, skb->len - 2); /* CRC */
+ put_unaligned_le16(crc, skb_put(skb, 2));
}
rcu_read_lock();
ieee802154_monitors_rx(local, skb);
- __ieee802154_rx_handle_packet(local, skb);
- rcu_read_unlock();
+ /* remove crc */
+ skb_trim(skb, skb->len - 2);
- return;
+ __ieee802154_rx_handle_packet(local, skb);
-fail:
- kfree_skb(skb);
+ rcu_read_unlock();
}
EXPORT_SYMBOL(ieee802154_rx);
--
2.1.2
--
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