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Commit b7889497 authored by Alexander Aring's avatar Alexander Aring Committed by Marcel Holtmann
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mac802154: rx: simplify crc receive handling 



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: default avatarAlexander Aring <alex.aring@gmail.com>
Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
parent 08c511a7

net/mac802154/rx.c

+12 −22
Original line number Diff line number Diff line
@@ -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);