ccc_mac.c

Fuint16_t ccc_hop_round_index(uint32_t block_index, uint32_t hop_key_rw, uint32_t n_round)

Default hopping round index S(i) in [0, n_round) for a ranging block.

block_index

Block index i.

hop_key_rw

HOP_Key_RW value keying the hop calculation.

n_round

Total number of ranging rounds.

returns

Round index in [0, n_round).

Fstatic void put_le16(uint8_t *p, uint16_t v)

Store a uint16 little-endian.

Fstatic void put_le32(uint8_t *p, uint32_t v)

Store a uint32 little-endian.

Fstatic uint16_t get_le16(const uint8_t *p)

Load a uint16 little-endian.

Fstatic uint32_t get_le32(const uint8_t *p)

Load a uint32 little-endian.

Fstatic bool mhr_vendor_oui_ok(const uint8_t *p)

True if the 3-byte little-endian OUI at p is the CCC or Aliro OUI (both accepted).

Fint ccc_build_mhr(const struct ccc_mhr_fields *f, uint8_t out[CCC_MHR_LEN])

Build the 23-byte SP0 MHR little-endian on the wire.

f

MHR fields (destination address, frame counter, key source, message ID, payload length).

out

Output buffer of at least CCC_MHR_LEN bytes.

returns

0 on success, -EINVAL if inputs are null.

Fint ccc_parse_mhr(const uint8_t in[CCC_MHR_LEN], struct ccc_mhr_fields *f)

Parse and validate a 23-byte SP0 MHR, extracting variable fields.

in

Input buffer of exactly CCC_MHR_LEN bytes.

f

Output structure to hold parsed fields (destination address, frame counter, key source, message ID, payload length).

returns

0 on success, -EINVAL on mismatch or null input.

Fint ccc_pre_poll_pack(const struct ccc_pre_poll *p, uint8_t out[CCC_PRE_POLL_LEN])

Pack a Pre-POLL payload little-endian.

p

Pre-POLL structure (session ID, STS index, ranging block, hop flag, round index).

out

Output buffer of at least CCC_PRE_POLL_LEN bytes.

returns

0 on success, -EINVAL if inputs are null.

Fint ccc_pre_poll_parse(const uint8_t in[CCC_PRE_POLL_LEN], struct ccc_pre_poll *p)

Parse a 13-byte Pre-POLL payload.

in

Input buffer of exactly CCC_PRE_POLL_LEN bytes.

p

Output structure to hold parsed fields (session ID, STS index, ranging block, hop flag, round index).

returns

0 on success, -EINVAL if inputs are null.

Fint ccc_final_data_pack(const struct ccc_final_data *f, uint8_t *out, size_t cap, size_t *len)

Pack a Final_Data payload little-endian.

f

Final_Data structure (session ID, ranging block, hop flag, round index, STS index, timestamp, responder list).

out

Output buffer.

cap

Capacity of output buffer.

len

Output: number of bytes written.

returns

0 on success, -EINVAL if inputs are null, responder count exceeds CCC_MAX_RESPONDERS, or buffer is too small.

Fint ccc_final_data_parse(const uint8_t *in, size_t len, struct ccc_final_data *f)

Parse a Final_Data payload.

in

Input buffer.

len

Length of input buffer.

f

Output structure to hold parsed fields (session ID, ranging block, hop flag, round index, STS index, timestamp, responder list).

returns

0 on success, -EINVAL if inputs are null, input length is inconsistent with responder count, or responder count exceeds CCC_MAX_RESPONDERS.

Fstatic uint32_t slot_offset(const struct ccc_ran_params *p, enum ccc_slot slot, uint8_t responder)

STS-index offset of a slot within its ranging round.

Fuint16_t ccc_block_round(const struct ccc_ran_params *p, uint32_t block)

The ranging round a block uses (block 0 uses round 0; continuous hopping uses S(i) for i>=1).

p

Ranging parameters.

block

Block index.

returns

Round index in [0, n_round).

Fuint32_t ccc_slot_sts_index(const struct ccc_ran_params *p, uint32_t block, uint16_t round, enum ccc_slot slot, uint8_t responder)

STS index for one slot of a ranging round (wraps mod 2^32).

p

Ranging parameters.

block

Block index.

round

Round index.

slot

Slot type (POLL, Response, or Final).

responder

Responder index.

returns

STS index for the slot.

Fstruct ccc_hop_decision ccc_initiator_next_hop(const struct ccc_ran_params *p, uint32_t block)

The initiator's hop decision for the block after block, written into its Final_Data.

p

Ranging parameters.

block

Block index.

returns

Hop decision (hop flag and next round index); both zero if hopping is disabled or params are null.

Fuint32_t ccc_ds_twr_tof(const struct ccc_ds_twr *t)

DS-TWR one-way time-of-flight in timestamp ticks.

t

DS-TWR intervals (round-trip and reply times at both ends).

returns

Time-of-flight in ticks, or 0 if the denominator is 0 or input is null.

Fint ccc_responder_ds_twr(const struct ccc_final_data *fd, uint8_t responder, uint32_t t_reply1, uint32_t t_round2, struct ccc_ds_twr *out)

Assemble the DS-TWR intervals at the responder from a received Final_Data.

Fbool ccc_ursk_exhausted(const struct ccc_ran_params *p, uint32_t block)

Whether the current URSK is exhausted for a ranging block (true once its highest STS index would exceed 2^31-1).