ieee802154: add ieee802154_skb_dst_pan helper

This patch adds ieee802154_skb_dst_pan function to get the pointer
address of the destination pan id at skb mac pointer.

Signed-off-by: Alexander Aring <aar@pengutronix.de>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/include/linux/ieee802154.h b/include/linux/ieee802154.h
index acedbb6..91f4665 100644 (file)
--- a/include/linux/ieee802154.h
+++ b/include/linux/ieee802154.h
@@ -31,6 +31,8 @@
 #define IEEE802154_MIN_PSDU_LEN                9
 #define IEEE802154_FCS_LEN             2
 #define IEEE802154_MAX_AUTH_TAG_LEN    16
+#define IEEE802154_FC_LEN              2
+#define IEEE802154_SEQ_LEN             1
 
 /*  General MAC frame format:
  *  2 bytes: Frame Control
@@ -221,9 +223,14 @@ enum {
 #define IEEE802154_FCTL_ACKREQ         0x0020
 #define IEEE802154_FCTL_SECEN          0x0004
 #define IEEE802154_FCTL_INTRA_PAN      0x0040
+#define IEEE802154_FCTL_DADDR          0x0c00
 
 #define IEEE802154_FTYPE_DATA          0x0001
 
+#define IEEE802154_FCTL_ADDR_NONE      0x0000
+#define IEEE802154_FCTL_DADDR_SHORT    0x0800
+#define IEEE802154_FCTL_DADDR_EXTENDED 0x0c00
+
 /*
  * ieee802154_is_data - check if type is IEEE802154_FTYPE_DATA
  * @fc: frame control bytes in little-endian byteorder
@@ -261,6 +268,15 @@ static inline bool ieee802154_is_intra_pan(__le16 fc)
        return fc & cpu_to_le16(IEEE802154_FCTL_INTRA_PAN);
 }
 
+/*
+ * ieee802154_daddr_mode - get daddr mode from fc
+ * @fc: frame control bytes in little-endian byteorder
+ */
+static inline __le16 ieee802154_daddr_mode(__le16 fc)
+{
+       return fc & cpu_to_le16(IEEE802154_FCTL_DADDR);
+}
+
 /**
  * ieee802154_is_valid_psdu_len - check if psdu len is valid
  * available lengths:

diff --git a/include/net/mac802154.h b/include/net/mac802154.h
index e465c85..b3f7cd8 100644 (file)
--- a/include/net/mac802154.h
+++ b/include/net/mac802154.h
@@ -257,6 +257,35 @@ static inline __le16 ieee802154_get_fc_from_skb(const struct sk_buff *skb)
        return get_unaligned_le16(skb_mac_header(skb));
 }
 
+/**
+ * ieee802154_skb_dst_pan - get the pointer to destination pan field
+ * @fc: mac header frame control field
+ * @skb: skb where the destination pan pointer will be get from
+ */
+static inline unsigned char *ieee802154_skb_dst_pan(__le16 fc,
+                                                   const struct sk_buff *skb)
+{
+       unsigned char *dst_pan;
+
+       switch (ieee802154_daddr_mode(fc)) {
+       case cpu_to_le16(IEEE802154_FCTL_ADDR_NONE):
+               dst_pan = NULL;
+               break;
+       case cpu_to_le16(IEEE802154_FCTL_DADDR_SHORT):
+       case cpu_to_le16(IEEE802154_FCTL_DADDR_EXTENDED):
+               dst_pan = skb_mac_header(skb) +
+                         IEEE802154_FC_LEN +
+                         IEEE802154_SEQ_LEN;
+               break;
+       default:
+               WARN_ONCE(1, "invalid addr mode detected");
+               dst_pan = NULL;
+               break;
+       }
+
+       return dst_pan;
+}
+
 /**
  * ieee802154_be64_to_le64 - copies and convert be64 to le64
  * @le64_dst: le64 destination pointer