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authorMauro <you@example.com>2021-06-30 07:57:22 +0000
committerMauro Sardara <msardara@cisco.com>2021-07-06 16:16:04 +0000
commit08233d44a6cfde878d7e10bca38ae935ed1c8fd5 (patch)
tree7ecc534d55bdc7e8dd15ecab084720910bcdf4d9 /libtransport/src/protocols/fec/rely.cc
parent147ba39bed26887f5eba84757e2463ab8e370a9a (diff)
[HICN-713] Transport Library Major Refactoring 2
Co-authored-by: Luca Muscariello <muscariello@ieee.org> Co-authored-by: Michele Papalini <micpapal@cisco.com> Co-authored-by: Olivier Roques <oroques+fdio@cisco.com> Co-authored-by: Giulio Grassi <gigrassi@cisco.com> Signed-off-by: Mauro Sardara <msardara@cisco.com> Change-Id: I5b2c667bad66feb45abdb5effe22ed0f6c85d1c2
Diffstat (limited to 'libtransport/src/protocols/fec/rely.cc')
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diff --git a/libtransport/src/protocols/fec/rely.cc b/libtransport/src/protocols/fec/rely.cc
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+/*
+ * Copyright (c) 2021 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <glog/logging.h>
+#include <hicn/transport/core/global_object_pool.h>
+#include <protocols/fec/rely.h>
+
+#include <rely/packet.hpp>
+
+namespace transport {
+namespace protocol {
+namespace fec {
+
+RelyEncoder::RelyEncoder(uint32_t k, uint32_t n, uint32_t seq_offset)
+ : RelyBase(k, n) {
+ configure(kmtu, ktimeout, kmax_stream_size);
+ set_repair_trigger(k_, n_ - k_, n_ - k_);
+}
+
+void RelyEncoder::onPacketProduced(core::ContentObject &content_object,
+ uint32_t offset) {
+ // Get pointer to payload, leaving space to insert FEC header.
+ // TODO Check if this additional header is really needed.
+ auto data = content_object.writableData() + offset - sizeof(fec_header);
+ auto length = content_object.length() - offset + sizeof(fec_header);
+
+ // Check packet length does not exceed maximum length supported by the
+ // encoder (otherwise segmentation would take place).
+ assert(length < max_packet_bytes());
+ DLOG_IF(INFO, VLOG_IS_ON(4))
+ << "Encoding packet of length " << length - sizeof(fec_header);
+
+ // Get the suffix. With rely we need to write it in the fec_header in order to
+ // be able to recognize the seq number upon recovery.
+ auto suffix = content_object.getName().getSuffix();
+ DLOG_IF(INFO, VLOG_IS_ON(4)) << "Producing packet " << suffix
+ << " (index == " << current_index_ << ")";
+
+ // Consume payload. Add fec_header in front before feeding payload to encoder,
+ // and copy original content of packet
+ fec_header *h = reinterpret_cast<fec_header *>(data);
+ fec_header copy = *h;
+ h->setSeqNumberBase(suffix);
+ auto packets = consume(data, length, getCurrentTime());
+ assert(packets == 1);
+
+ // Update packet counter
+ current_index_ += packets;
+
+ // Restore original packet content and increment data pointer to the correct
+ // position
+ *h = copy;
+ data += sizeof(fec_header);
+
+ // Check position of this packet inside N size block
+ auto i = current_index_ % n_;
+
+ // encoder will produce a source packet
+ if (i <= k_) {
+ // Rely modifies the payload of the packet. We replace the packet with the
+ // one returned by rely.
+ // TODO Optimize it by copying only the RELY header
+
+ // Be sure encoder can produce
+ assert(can_produce());
+
+ // Check new payload size and make sure it fits in packet buffer
+ auto new_payload_size = produce_bytes();
+ int difference = new_payload_size - length;
+
+ assert(difference > 0);
+ assert(content_object.ensureCapacity(difference));
+
+ // Update length
+ DLOG_IF(INFO, VLOG_IS_ON(4)) << "The packet length will be incremented by "
+ << difference + sizeof(fec_header);
+ content_object.append(difference + sizeof(fec_header));
+ content_object.updateLength();
+
+ // Make sure we got a source packet, otherwise we would put a repair symbol
+ // in a source packet
+ assert(rely::packet_is_systematic(produce_data()));
+
+ // Copy rely packet replacing old source packet.
+ std::memcpy(data, produce_data(), new_payload_size);
+
+ // Advance the encoder to next symbol.
+ produce_next();
+ }
+
+#if 0
+ if (i == k_) {
+ // Ensure repair are generated after k source packets
+ flush_repair();
+ }
+#endif
+
+ // Here we should produce all the repair packets
+ while (can_produce()) {
+ // The current index MUST be k_, because we enforce n - k repair to be
+ // produced after k sources
+ assert(current_index_ == k_);
+
+ buffer packet;
+ if (!buffer_callback_) {
+ // If no callback is installed, let's allocate a buffer from global pool
+ packet = core::PacketManager<>::getInstance().getMemBuf();
+ packet->append(produce_bytes());
+ } else {
+ // Otherwise let's ask a buffer to the caller.
+ packet = buffer_callback_(produce_bytes());
+ }
+
+ DLOG_IF(INFO, VLOG_IS_ON(4))
+ << "Producing symbol of size " << produce_bytes();
+
+ // Copy symbol to packet buffer
+ std::memcpy(packet->writableData(), produce_data(), produce_bytes());
+
+ // Push symbol in repair_packets
+ packets_.emplace_back(0, std::move(packet));
+
+ // Advance the encoder
+ produce_next();
+ }
+
+ // Print number of unprotected symbols
+ DLOG_IF(INFO, VLOG_IS_ON(4))
+ << "Number of unprotected symbols: " << unprotected_symbols();
+
+ // If we have generated repair symbols, let's notify caller via the installed
+ // callback
+ if (packets_.size()) {
+ assert(packets_.size() == n_ - k_);
+ fec_callback_(packets_);
+ packets_.clear();
+ current_index_ = 0;
+ }
+}
+
+RelyDecoder::RelyDecoder(uint32_t k, uint32_t n, uint32_t seq_offset)
+ : RelyBase(k, n, seq_offset) {
+ configure(kmtu, ktimeout, kmax_stream_size);
+}
+
+void RelyDecoder::onDataPacket(core::ContentObject &content_object,
+ uint32_t offset) {
+ // Adjust pointers to point to packet payload
+ auto data = content_object.writableData() + offset;
+ auto size = content_object.length() - offset;
+
+ // Pass payload to decoder
+ consume(data, size, getCurrentTime());
+
+ // Drain decoder if possible
+ while (can_produce()) {
+ // Get size of decoded packet
+ auto size = produce_bytes();
+
+ // Get buffer to copy packet in
+ auto packet = core::PacketManager<>::getInstance().getMemBuf();
+
+ // Copy buffer
+ packet->append(size);
+ std::memcpy(packet->writableData(), produce_data(), size);
+
+ // Read seq number
+ fec_header *h = reinterpret_cast<fec_header *>(packet->writableData());
+ uint32_t index = h->getSeqNumberBase();
+
+ DLOG_IF(INFO, VLOG_IS_ON(4))
+ << "The index written in the packet is " << index;
+
+ // Remove FEC header
+ packet->trimStart(sizeof(fec_header));
+
+ // Save packet in buffer
+ packets_.emplace_back(index, std::move(packet));
+
+ // Advance to next packet
+ produce_next();
+ }
+
+ // If we produced packets, lets notify the caller via the callback
+ if (packets_.size() > 0) {
+ fec_callback_(packets_);
+ packets_.clear();
+ }
+}
+
+} // namespace fec
+} // namespace protocol
+} // namespace transport \ No newline at end of file