/**
* "Generate a BlockInfoVec for the outgoing link and put it into xmit_blocks_." [DTN2]
*
* @return a list of new BLockInfo
*/
public static BlockInfoVec prepare_blocks(Bundle bundle, final Link link) {
// "create a new block list for the outgoing link by first calling
// prepare on all the BlockProcessor classes for the blocks that
// arrived on the link" [DTN2]
BlockInfoVec xmit_blocks = bundle.xmit_link_block_set().create_blocks(link);
BlockInfoVec recv_blocks = bundle.recv_blocks();
if (recv_blocks.size() > 0) {
// "if there is a received block, the first one better be the primary"
// [DTN2]
assert (recv_blocks.front().type() == bundle_block_type_t.PRIMARY_BLOCK);
Iterator<BlockInfo> iter = recv_blocks.iterator();
while (iter.hasNext()) {
BlockInfo block = iter.next();
if (bundle.fragmented_incoming()
&& xmit_blocks.find_block(BundleProtocol.bundle_block_type_t.PAYLOAD_BLOCK) != null) {
continue;
}
block
.owner()
.prepare(bundle, xmit_blocks, block, link, BlockInfo.list_owner_t.LIST_RECEIVED);
}
} else {
BPF.getInstance().getBPFLogger().debug(TAG, "adding primary and payload block");
BlockProcessor bp = find_processor(BundleProtocol.bundle_block_type_t.PRIMARY_BLOCK);
bp.prepare(bundle, xmit_blocks, null, link, BlockInfo.list_owner_t.LIST_NONE);
bp = find_processor(bundle_block_type_t.PAYLOAD_BLOCK);
bp.prepare(bundle, xmit_blocks, null, link, BlockInfo.list_owner_t.LIST_NONE);
}
// "now we also make sure to prepare() on any registered processors
// that don't already have a block in the output list. this
// handles the case where we have a locally generated block with
// nothing in the recv_blocks vector" [DTN2]
Iterator<BlockProcessor> itr = processors_.iterator();
while (itr.hasNext()) {
BlockProcessor bp = itr.next();
if (!xmit_blocks.has_block(bp.block_type())) {
bp.prepare(bundle, xmit_blocks, null, link, BlockInfo.list_owner_t.LIST_NONE);
}
}
// Now prepare security blocks
BPF.getInstance().getBPFLogger().debug(TAG, "Now preparing security blocks...");
Security.prepare_out_blocks(bundle, link, xmit_blocks);
return xmit_blocks;
}
/**
* "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;
}