/** "Constructor-like function to create a new custody signal bundle." [DTN2] */
public static Bundle create_custody_signal(
final Bundle orig_bundle,
final EndpointID source_eid,
boolean succeeded,
BundleProtocol.custody_signal_reason_t reason) {
Bundle bundle = new Bundle(location_t.MEMORY);
bundle.source().assign(source_eid);
if (orig_bundle.custodian().equals(EndpointID.NULL_EID())) {
Logger.getInstance()
.error(
TAG,
String.format(
"create_custody_signal(for bundle id %d): "
+ "custody signal cannot be generated due to custodian is null eid",
orig_bundle.bundleid()));
}
bundle.dest().assign(orig_bundle.custodian());
bundle.replyto().assign(EndpointID.NULL_EID());
bundle.custodian().assign(EndpointID.NULL_EID());
bundle.set_is_admin(true);
bundle.set_expiration(orig_bundle.expiration());
int sdnv_encoding_len = 0;
int signal_len = 0;
// "format of custody signals:
//
// 1 byte admin payload type and flags
// 1 byte status code
// SDNV [Fragment Offset (if present)]
// SDNV [Fragment Length (if present)]
// SDNVx2 Time of custody signal
// SDNVx2 Copy of bundle X's Creation Timestamp
// SDNV Length of X's source endpoint ID
// vari Source endpoint ID of bundle X
//
// first calculate the length
//
// the non-optional, fixed-length fields above:" [DTN2]
signal_len = 1 + 1;
// "the 2 SDNV fragment fields:" [DTN2]
if (orig_bundle.is_fragment()) {
signal_len += SDNV.encoding_len(orig_bundle.frag_offset());
signal_len += SDNV.encoding_len(orig_bundle.orig_length());
}
// "Time field, set to the current time:" [DTN2]
DTNTime now = new DTNTime();
signal_len += DTNTime.SDNV_encoding_len(now);
// "The bundle's creation timestamp:" [DTN2]
signal_len += BundleTimestamp.SDNV_encoding_len(orig_bundle.creation_ts());
// the Source Endpoint ID length and value
signal_len += SDNV.encoding_len(orig_bundle.source().length()) + orig_bundle.source().length();
//
// "We got all the data ready, now format the buffer" [DTN2]
//
IByteBuffer bp = new SerializableByteBuffer(signal_len);
int len = signal_len;
bp.rewind();
// "Admin Payload Type and flags" [DTN2]
byte type_and_flags_byte =
(byte) (BundleProtocol.admin_record_type_t.ADMIN_CUSTODY_SIGNAL.getCode() << 4);
if (orig_bundle.is_fragment()) {
type_and_flags_byte |= BundleProtocol.admin_record_flags_t.ADMIN_IS_FRAGMENT.getCode();
}
bp.put(type_and_flags_byte);
len--;
// Status_Flag_Byte consists of Success flag and reason code
byte status_flag_byte = (byte) ((succeeded ? 1 : 0) << 7 | (reason.getCode() & 0x7f));
bp.put(status_flag_byte);
len--;
// "The 2 Fragment Fields" [DTN2]
if (orig_bundle.is_fragment()) {
sdnv_encoding_len = SDNV.encode(orig_bundle.frag_offset(), bp, len);
assert (sdnv_encoding_len > 0);
len -= sdnv_encoding_len;
sdnv_encoding_len = SDNV.encode(orig_bundle.orig_length(), bp, len);
assert (sdnv_encoding_len > 0);
len -= sdnv_encoding_len;
}
// DTNTime which is a time of signal field
sdnv_encoding_len = DTNTime.SDNV_encoding_len(now);
assert (sdnv_encoding_len > 0);
DTNTime.encodeSDNV(now, bp);
len -= sdnv_encoding_len;
// "Copy of bundle X's Creation Timestamp" [DTN2]
sdnv_encoding_len = BundleTimestamp.SDNV_encoding_len(orig_bundle.creation_ts());
assert (sdnv_encoding_len > 0);
BundleTimestamp.encodeSDNV(orig_bundle.creation_ts(), bp);
len -= sdnv_encoding_len;
// "The Endpoint ID length and data" [DTN2]
sdnv_encoding_len = SDNV.encode(orig_bundle.source().length(), bp, len);
assert (sdnv_encoding_len > 0);
len -= sdnv_encoding_len;
assert (len == orig_bundle.source().length());
bp.put(orig_bundle.source().byte_array());
//
// "Finished generating the payload" [DTN2]
//
bp.rewind();
bundle.payload().set_data(bp, signal_len);
return bundle;
}
