Function onion_decode

common/onion.c:110–218

}

struct onion_payload *onion_decode(const tal_t *ctx,
				   const struct route_step *rs,
				   const struct pubkey *blinding,
				   const struct secret *blinding_ss,
				   const u64 *accepted_extra_tlvs,
				   u64 *failtlvtype,
				   size_t *failtlvpos)
{
	struct onion_payload *p = tal(ctx, struct onion_payload);
	const u8 *cursor = rs->raw_payload;
	size_t max = tal_bytelen(cursor), len;
	struct tlv_tlv_payload *tlv;

	/* BOLT-remove-legacy-onion #4:
	 * 1. type: `hop_payloads`
	 * 2. data:
	 *    * [`bigsize`:`length`]
	 *    * [`length*byte`:`payload`]
	 */
	len = fromwire_bigsize(&cursor, &max);
	if (!cursor || len > max) {
		*failtlvtype = 0;
		*failtlvpos = tal_bytelen(rs->raw_payload);
		goto fail_no_tlv;
	}

	/* We do this manually so we can accept extra types, and get
	 * error off and type. */
	tlv = tlv_tlv_payload_new(p);
	if (!fromwire_tlv(&cursor, &max, tlvs_tlv_tlv_payload,
			  TLVS_ARRAY_SIZE_tlv_tlv_payload,
			  tlv, &tlv->fields, accepted_extra_tlvs,
			  failtlvpos, failtlvtype)) {
		goto fail;
	}

	/* BOLT #4:
	 *
	 * The reader:
	 *   - MUST return an error if `amt_to_forward` or
	 *     `outgoing_cltv_value` are not present.
	 */
	if (!tlv->amt_to_forward) {
		*failtlvtype = TLV_TLV_PAYLOAD_AMT_TO_FORWARD;
		goto field_bad;
	}
	if (!tlv->outgoing_cltv_value) {
		*failtlvtype = TLV_TLV_PAYLOAD_OUTGOING_CLTV_VALUE;
		goto field_bad;
	}

	p->amt_to_forward = amount_msat(*tlv->amt_to_forward);
	p->outgoing_cltv = *tlv->outgoing_cltv_value;

	/* BOLT #4:
	 *
	 * The writer:
	 *...