Hi all,
I am having a hard time understanding how the "ieee802154_set_frame_hdr"
function, found in this
link<https://github.com/RIOT-OS/RIOT/blob/master/sys/net/link_layer/ieee802154/ieee802154.c>,
sets the Frame Control Field (FCF) for 802.15.4 frame header.
Following the IEEE 802.15.4 FCF format, frame version should be at the 12-13th
bit of the 2-byte FCF, while in the function code, the frame version was set at
the 11th bit. Does it uses different FCF format or am I missing something?
This is the first part of the function:
size_t ieee802154_set_frame_hdr(uint8_t *buf, const uint8_t *src, size_t
src_len,
const uint8_t *dst, size_t dst_len,
le_uint16_t src_pan, le_uint16_t dst_pan,
uint8_t flags, uint8_t seq)
{
int pos = 3; /* 0-1: FCS, 2: seq */
uint8_t type = (flags & IEEE802154_FCF_TYPE_MASK);
buf[0] = flags;
buf[1] = IEEE802154_FCF_VERS_V1; // IEEE802154_FCF_VERS_V1 is
defined as 0x10
if (((src_len != 0) && (src == NULL)) ||
((dst_len != 0) && (dst == NULL))) {
return 0;
}
...
...
The first two bytes of the *buf represent the FCF. I would appreciate it if
someone explains or provides the FCF format that RIOT-OS uses.
Thank you,
Ahed
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