/**
* "Generate contents for the given BlockInfoVec on the given Link." [DTN2]
*
* @return "the total length of the formatted blocks for this bundle." [DTN2]
*/
public static int generate_blocks(Bundle bundle, BlockInfoVec blocks, final Link link) {
// "now assert there's at least 2 blocks (primary + payload) and
// that the primary is first" [DTN2]
assert (blocks.size() >= 2);
assert (blocks.front().type() == bundle_block_type_t.PRIMARY_BLOCK);
// "now we make a pass through the list and call generate on
// each block processor" [DTN2]
for (int i = 0; i < blocks.size(); i++) {
boolean last = i == blocks.size() - 1;
BlockInfo iter = blocks.get(i);
iter.owner().generate(bundle, blocks, iter, link, last);
BPF.getInstance()
.getBPFLogger()
.debug(
TAG,
String.format(
"generated block (owner %s type %s) "
+ "data_offset %d data_length %d , contents_length %d",
iter.owner().block_type(),
iter.type(),
iter.data_offset(),
iter.data_length(),
iter.contents().position()));
if (last) {
assert ((iter.flags() & BundleProtocol.block_flag_t.BLOCK_FLAG_LAST_BLOCK.getCode()) != 0);
} else {
assert ((iter.flags() & BundleProtocol.block_flag_t.BLOCK_FLAG_LAST_BLOCK.getCode()) == 0);
}
}
// "Now that all the EID references are added to the dictionary,
// generate the primary block." [DTN2]
PrimaryBlockProcessor pbp =
(PrimaryBlockProcessor) find_processor(BundleProtocol.bundle_block_type_t.PRIMARY_BLOCK);
assert (blocks.front().owner() == pbp);
pbp.generate_primary(bundle, blocks, blocks.front());
// "make a final pass through, calling finalize() and extracting
// the block length" [DTN2]
int total_len = 0;
for (int i = blocks.size() - 1; i >= 0; i--) {
BlockInfo iter = blocks.get(i);
iter.owner().finalize(bundle, blocks, iter, link);
total_len += iter.full_length();
}
return total_len;
}
/**
* "Temporary helper function to find the offset of the first byte of the payload in a
* BlockInfoVec." [DTN2]
*/
public static int payload_offset(final BlockInfoVec blocks) {
int ret = 0;
Iterator<BlockInfo> itr = blocks.iterator();
while (itr.hasNext()) {
BlockInfo block = itr.next();
if (block.type() == BundleProtocol.bundle_block_type_t.PAYLOAD_BLOCK) {
ret += block.data_offset();
return ret;
}
ret += block.full_length();
}
return ret;
}
/**
* "Loop through the bundle's received block list to validate each entry." [DTN2]
*
* @return "true if the bundle is valid, false if it should be deleted." [DTN2]
*/
public static boolean validate(
Bundle bundle,
status_report_reason_t[] reception_reason,
status_report_reason_t[] deletion_reason) {
int primary_blocks = 0, payload_blocks = 0;
BlockInfoVec recv_blocks = bundle.recv_blocks();
// "a bundle must include at least two blocks (primary and payload)"
// [DTN2]
if (recv_blocks.size() < 2) {
BPF.getInstance().getBPFLogger().error(TAG, "bundle fails to contain at least two blocks");
deletion_reason[0] = BundleProtocol.status_report_reason_t.REASON_BLOCK_UNINTELLIGIBLE;
return false;
}
// "the first block of a bundle must be a primary block" [DTN2]
if (recv_blocks.front().type() != BundleProtocol.bundle_block_type_t.PRIMARY_BLOCK) {
BPF.getInstance().getBPFLogger().error(TAG, "bundle fails to contain a primary block");
deletion_reason[0] = BundleProtocol.status_report_reason_t.REASON_BLOCK_UNINTELLIGIBLE;
return false;
}
// "validate each individual block" [DTN2]
int last_block_index = recv_blocks.size() - 1;
for (int i = 0; i < recv_blocks.size(); i++) {
BlockInfo current_block = recv_blocks.get(i);
// "a block may not have enough data for the preamble" [DTN2]
if (current_block.data_offset() == 0) {
// "either the block is not the last one and something went
// badly wrong, or it is the last block present" [DTN2]
if (i != last_block_index) {
BPF.getInstance().getBPFLogger().error(TAG, "bundle block too short for the preamble");
deletion_reason[0] = BundleProtocol.status_report_reason_t.REASON_BLOCK_UNINTELLIGIBLE;
return false;
}
// "this is the last block, so drop it" [DTN2]
BPF.getInstance().getBPFLogger().debug(TAG, "forgetting preamble-starved last block");
recv_blocks.remove(current_block);
if (recv_blocks.size() < 2) {
BPF.getInstance()
.getBPFLogger()
.error(TAG, "bundle fails to contain at least two blocks");
deletion_reason[0] = BundleProtocol.status_report_reason_t.REASON_BLOCK_UNINTELLIGIBLE;
return false;
}
// "continue with the tests; results may have changed now that
// a different block is last" [DTN2]
return false;
} else {
if (current_block.type() == BundleProtocol.bundle_block_type_t.PRIMARY_BLOCK) {
primary_blocks++;
}
if (current_block.type() == BundleProtocol.bundle_block_type_t.PAYLOAD_BLOCK) {
payload_blocks++;
}
}
if (!current_block
.owner()
.validate(bundle, recv_blocks, current_block, reception_reason, deletion_reason)) {
return false;
}
// "a bundle's last block must be flagged as such,
// and all other blocks should not be flagged" [DTN2]
if (i == last_block_index) {
if (!current_block.last_block()) {
if (!bundle.fragmented_incoming()) {
BPF.getInstance().getBPFLogger().error(TAG, "bundle's last block not flagged");
deletion_reason[0] = BundleProtocol.status_report_reason_t.REASON_BLOCK_UNINTELLIGIBLE;
return false;
} else {
BPF.getInstance()
.getBPFLogger()
.debug(TAG, "bundle's last block not flagged, but " + "it is a reactive fragment");
}
}
} else {
if (current_block.last_block()) {
BPF.getInstance().getBPFLogger().error(TAG, "bundle block incorrectly flagged as last");
deletion_reason[0] = BundleProtocol.status_report_reason_t.REASON_BLOCK_UNINTELLIGIBLE;
return false;
}
}
}
// "a bundle must contain one, and only one, primary block" [DTN2]
if (primary_blocks != 1) {
BPF.getInstance()
.getBPFLogger()
.error(TAG, String.format("bundle contains %d primary blocks", primary_blocks));
deletion_reason[0] = BundleProtocol.status_report_reason_t.REASON_BLOCK_UNINTELLIGIBLE;
return false;
}
// "a bundle must not contain more than one payload block" [DTN2]
if (payload_blocks > 1) {
BPF.getInstance()
.getBPFLogger()
.error(TAG, String.format("bundle contains %d payload blocks", payload_blocks));
deletion_reason[0] = BundleProtocol.status_report_reason_t.REASON_BLOCK_UNINTELLIGIBLE;
return false;
}
return true;
}