Files
voxelforge/tests/testTransport.cpp

398 lines
13 KiB
C++

#include "testHarness.h"
#include "vf/Transport.h"
#include <cstdint>
#include <string>
#include <vector>
using namespace vf;
namespace {
ByteBuffer messageOf(uint32_t index, std::size_t size) {
ByteBuffer payload;
payload.reserve(size);
uint32_t state = index * 2654435761u + 12345u;
for (std::size_t i = 0; i < size; ++i) {
state = state * 1664525u + 1013904223u;
payload.push_back(static_cast<uint8_t>((state >> 16) & 0xffu));
}
// The first four bytes carry the index so the receiver can prove ordering.
for (int byte = 0; byte < 4 && static_cast<std::size_t>(byte) < payload.size(); ++byte)
payload[static_cast<std::size_t>(byte)] =
static_cast<uint8_t>((index >> (8 * byte)) & 0xffu);
return payload;
}
uint32_t indexOf(const ByteBuffer& payload) {
uint32_t index = 0;
for (int byte = 3; byte >= 0; --byte)
index = (index << 8) | payload[static_cast<std::size_t>(byte)];
return index;
}
// One tick of a two-endpoint exchange, always in the same order so a run is
// reproducible from the link seed alone.
void stepPair(Transport& a, Transport& b, uint64_t tick) {
a.pump(tick);
a.flush(tick);
b.pump(tick);
b.flush(tick);
}
} // namespace
VF_TEST(loopbackLinkReplaysTheSameImpairmentsForTheSameSeed) {
LinkQuality quality;
quality.lossPercent = 30;
quality.duplicatePercent = 15;
quality.reorderPercent = 25;
quality.latencyTicks = 2;
quality.seed = 0xfeedfacecafebeefull;
std::vector<std::string> runs;
for (int attempt = 0; attempt < 2; ++attempt) {
LoopbackLink link(quality);
std::string trace;
for (uint64_t tick = 0; tick < 60; ++tick) {
ByteBuffer payload = messageOf(static_cast<uint32_t>(tick), 8);
link.send(0, payload, tick);
std::vector<ByteBuffer> arrived;
link.receive(1, tick, arrived);
for (const ByteBuffer& one : arrived) {
trace += std::to_string(tick);
trace += ':';
trace += std::to_string(indexOf(one));
trace += ' ';
}
}
trace += "d";
trace += std::to_string(link.droppedCount());
trace += "u";
trace += std::to_string(link.duplicatedCount());
runs.push_back(trace);
}
CHECK(runs[0] == runs[1]);
CHECK(runs[0].size() > 40u);
LoopbackLink probe(quality);
for (uint64_t tick = 0; tick < 200; ++tick) probe.send(0, messageOf(1, 4), tick);
CHECK(probe.droppedCount() > 30u);
CHECK(probe.duplicatedCount() > 10u);
CHECK(probe.delayedCount() > 20u);
}
VF_TEST(reliableChannelDeliversEveryMessageExactlyOnceInOrderOverALossyLink) {
LinkQuality quality;
quality.lossPercent = 30;
quality.duplicatePercent = 12;
quality.reorderPercent = 25;
quality.reorderExtraTicks = 4;
quality.latencyTicks = 2;
quality.seed = 0x1234abcd5678ef01ull;
LoopbackLink link(quality);
TransportConfig config;
config.mtu = 256;
config.retransmitTimeoutTicks = 8;
config.sendWindow = 16;
Transport sender(link, 0, config);
Transport receiver(link, 1, config);
const uint32_t messageCount = 240;
for (uint32_t i = 0; i < messageCount; ++i) {
ByteBuffer payload = messageOf(i, 40 + (i % 90));
sender.sendReliable(payload);
}
std::vector<uint32_t> order;
for (uint64_t tick = 0; tick < 4000 && order.size() < messageCount; ++tick) {
stepPair(sender, receiver, tick);
ByteBuffer got;
while (receiver.popReliable(got)) order.push_back(indexOf(got));
}
CHECK_EQ(order.size(), static_cast<std::size_t>(messageCount));
bool inOrder = true;
for (std::size_t i = 0; i < order.size(); ++i)
if (order[i] != static_cast<uint32_t>(i)) inOrder = false;
CHECK(inOrder);
// Payloads survive intact, not just their headers.
for (uint32_t i = 0; i < 5 && i < order.size(); ++i) CHECK_EQ(order[i], i);
CHECK(link.droppedCount() > 20u);
CHECK(link.duplicatedCount() > 5u);
CHECK(sender.stats().retransmitted > 0u);
CHECK(receiver.stats().duplicatesDropped + receiver.stats().staleDropped > 0u);
CHECK_EQ(receiver.stats().messagesDelivered, static_cast<uint64_t>(messageCount));
}
VF_TEST(reliableMessagesLargerThanTheMtuAreFragmentedAndReassembledByteForByte) {
LinkQuality quality;
quality.lossPercent = 20;
quality.reorderPercent = 30;
quality.reorderExtraTicks = 3;
quality.latencyTicks = 1;
quality.seed = 0x77aabbccddee0011ull;
LoopbackLink link(quality);
TransportConfig config;
config.mtu = 128;
config.retransmitTimeoutTicks = 5;
config.sendWindow = 8;
Transport sender(link, 0, config);
Transport receiver(link, 1, config);
ByteBuffer huge = messageOf(9, 20000);
CHECK(huge.size() > sender.maxFragmentPayload() * 100);
sender.sendReliable(huge);
CHECK(sender.unackedFragmentCount() > 100u);
ByteBuffer got;
bool arrived = false;
uint64_t tick = 0;
for (; tick < 6000 && !arrived; ++tick) {
stepPair(sender, receiver, tick);
if (receiver.popReliable(got)) arrived = true;
}
CHECK(arrived);
// Let the last acks come back before asking whether anything is still unacked.
for (uint64_t settle = 0; settle < 40; ++settle) stepPair(sender, receiver, tick + settle);
CHECK_EQ(got.size(), huge.size());
CHECK(got == huge);
CHECK_EQ(sender.unackedFragmentCount(), static_cast<std::size_t>(0));
ByteBuffer extra;
CHECK(!receiver.popReliable(extra));
}
VF_TEST(unreliableChannelDropsAMessageOlderThanTheNewestOneAlreadyDelivered) {
LinkQuality slow;
slow.latencyTicks = 12;
slow.seed = 0x2222333344445555ull;
LoopbackLink link(slow);
TransportConfig config;
config.mtu = 256;
Transport sender(link, 0, config);
Transport receiver(link, 1, config);
sender.sendUnreliable(messageOf(0, 32));
sender.flush(0);
LinkQuality fast = slow;
fast.latencyTicks = 1;
link.setQuality(fast);
sender.sendUnreliable(messageOf(1, 32));
sender.flush(1);
std::vector<uint32_t> received;
for (uint64_t tick = 2; tick < 40; ++tick) {
receiver.pump(tick);
receiver.flush(tick);
ByteBuffer got;
while (receiver.popUnreliable(got)) received.push_back(indexOf(got));
}
CHECK_EQ(received.size(), static_cast<std::size_t>(1));
CHECK_EQ(received[0], 1u);
CHECK_EQ(receiver.stats().staleDropped, static_cast<uint64_t>(1));
CHECK_EQ(receiver.unreliableChannel().highestDeliveredMessageId(), 1u);
}
VF_TEST(unreliableMessagesAreNeverRetransmittedWhileReliableOnesAre) {
LinkQuality quality;
quality.lossPercent = 50;
quality.latencyTicks = 1;
quality.seed = 0x5a5a5a5a5a5a5a5aull;
LoopbackLink lossyUnreliable(quality);
TransportConfig config;
config.mtu = 256;
config.retransmitTimeoutTicks = 4;
Transport unreliableSender(lossyUnreliable, 0, config);
Transport unreliableReceiver(lossyUnreliable, 1, config);
for (uint32_t i = 0; i < 40; ++i) unreliableSender.sendUnreliable(messageOf(i, 24));
std::size_t unreliableArrived = 0;
for (uint64_t tick = 0; tick < 200; ++tick) {
stepPair(unreliableSender, unreliableReceiver, tick);
ByteBuffer got;
while (unreliableReceiver.popUnreliable(got)) ++unreliableArrived;
}
CHECK(unreliableArrived < 40u);
CHECK_EQ(unreliableSender.stats().retransmitted, static_cast<uint64_t>(0));
LoopbackLink lossyReliable(quality);
Transport reliableSender(lossyReliable, 0, config);
Transport reliableReceiver(lossyReliable, 1, config);
for (uint32_t i = 0; i < 40; ++i) reliableSender.sendReliable(messageOf(i, 24));
std::size_t reliableArrived = 0;
for (uint64_t tick = 0; tick < 600; ++tick) {
stepPair(reliableSender, reliableReceiver, tick);
ByteBuffer got;
while (reliableReceiver.popReliable(got)) ++reliableArrived;
}
CHECK_EQ(reliableArrived, static_cast<std::size_t>(40));
CHECK(reliableSender.stats().retransmitted > 0u);
CHECK(reliableSender.stats().datagramsLost > 0u);
}
VF_TEST(duplicatedDatagramsAreCountedAndNeverDeliveredTwice) {
LinkQuality quality;
quality.duplicatePercent = 100;
quality.latencyTicks = 1;
quality.seed = 0x0badc0de0badc0deull;
LoopbackLink link(quality);
TransportConfig config;
config.mtu = 256;
Transport sender(link, 0, config);
Transport receiver(link, 1, config);
for (uint32_t i = 0; i < 30; ++i) sender.sendReliable(messageOf(i, 60));
std::vector<uint32_t> order;
for (uint64_t tick = 0; tick < 200; ++tick) {
stepPair(sender, receiver, tick);
ByteBuffer got;
while (receiver.popReliable(got)) order.push_back(indexOf(got));
}
CHECK_EQ(order.size(), static_cast<std::size_t>(30));
for (std::size_t i = 0; i < order.size(); ++i) CHECK_EQ(order[i], static_cast<uint32_t>(i));
CHECK(receiver.stats().duplicatesDropped > 0u);
CHECK_EQ(link.duplicatedCount(), link.sentCount() - link.droppedCount());
CHECK(receiver.stats().datagramsReceived > receiver.stats().duplicatesDropped);
}
VF_TEST(theSendWindowCapsHowManyDatagramsCanBeUnacknowledgedAtOnce) {
LinkQuality quality;
quality.latencyTicks = 6;
quality.seed = 0x1010101020202020ull;
LoopbackLink link(quality);
TransportConfig config;
config.mtu = 96;
config.sendWindow = 4;
config.retransmitTimeoutTicks = 40;
Transport sender(link, 0, config);
Transport receiver(link, 1, config);
for (uint32_t i = 0; i < 60; ++i) sender.sendReliable(messageOf(i, 50));
std::size_t peakInFlight = 0;
std::size_t arrived = 0;
for (uint64_t tick = 0; tick < 900; ++tick) {
stepPair(sender, receiver, tick);
if (sender.inFlightDatagramCount() > peakInFlight)
peakInFlight = sender.inFlightDatagramCount();
ByteBuffer got;
while (receiver.popReliable(got)) ++arrived;
}
CHECK_EQ(peakInFlight, static_cast<std::size_t>(4));
CHECK_EQ(arrived, static_cast<std::size_t>(60));
}
VF_TEST(smoothedRoundTripTimeConvergesOnTheLinkLatency) {
LinkQuality quality;
quality.latencyTicks = 3;
quality.seed = 0x9999888877776666ull;
LoopbackLink link(quality);
TransportConfig config;
config.mtu = 256;
config.retransmitTimeoutTicks = 30;
Transport sender(link, 0, config);
Transport receiver(link, 1, config);
CHECK_EQ(sender.stats().smoothedRttTicks, 0.0);
for (uint32_t i = 0; i < 40; ++i) sender.sendReliable(messageOf(i, 20));
for (uint64_t tick = 0; tick < 120; ++tick) {
stepPair(sender, receiver, tick);
ByteBuffer got;
while (receiver.popReliable(got)) {
}
}
CHECK_NEAR(sender.stats().smoothedRttTicks, 6.0, 0.001);
CHECK_EQ(sender.stats().datagramsLost, static_cast<uint64_t>(0));
}
VF_TEST(theAckBitfieldConfirmsDatagramsWhoseOwnAckWasLost) {
LinkQuality quality;
quality.latencyTicks = 1;
quality.seed = 0x4242424242424242ull;
LoopbackLink link(quality);
TransportConfig config;
config.mtu = 96;
config.sendWindow = 32;
config.retransmitTimeoutTicks = 1000;
Transport sender(link, 0, config);
Transport receiver(link, 1, config);
for (uint32_t i = 0; i < 12; ++i) sender.sendReliable(messageOf(i, 50));
// Twelve datagrams leave, and the sender never pumps, so not a single ack
// has been seen when the burst is complete.
sender.flush(0);
CHECK_EQ(sender.inFlightDatagramCount(), static_cast<std::size_t>(12));
CHECK_EQ(sender.stats().datagramsSent, static_cast<uint64_t>(12));
CHECK_EQ(sender.stats().smoothedRttTicks, 0.0);
// A single hand-built ack: latest is sequence 11, and the history bitfield
// covers sequences 10 down to 0. Nothing else ever reaches the sender.
receiver.pump(1);
Datagram carrier;
carrier.sequence = 0;
carrier.ackLatest = 11;
carrier.ackHistory = 0x7ffu;
carrier.ackValid = true;
ByteWriter wire;
carrier.encode(wire);
link.send(1, wire.bytes(), 1);
sender.pump(2);
CHECK_EQ(sender.inFlightDatagramCount(), static_cast<std::size_t>(0));
CHECK_EQ(sender.unackedFragmentCount(), static_cast<std::size_t>(0));
CHECK_EQ(sender.stats().retransmitted, static_cast<uint64_t>(0));
CHECK(sender.stats().smoothedRttTicks > 0.0);
// The whole burst still arrived exactly once, in order.
std::vector<uint32_t> order;
for (uint64_t tick = 2; tick < 30; ++tick) {
receiver.pump(tick);
ByteBuffer got;
while (receiver.popReliable(got)) order.push_back(indexOf(got));
}
CHECK_EQ(order.size(), static_cast<std::size_t>(12));
for (std::size_t i = 0; i < order.size(); ++i) CHECK_EQ(order[i], static_cast<uint32_t>(i));
}
VF_TEST(aTransportWithNothingToSendStillAcknowledgesWithoutAnAckStorm) {
LinkQuality quality;
quality.latencyTicks = 1;
quality.seed = 0x0f0f0f0f0f0f0f0full;
LoopbackLink link(quality);
TransportConfig config;
config.mtu = 256;
config.retransmitTimeoutTicks = 20;
Transport sender(link, 0, config);
Transport receiver(link, 1, config);
sender.sendReliable(messageOf(0, 40));
for (uint64_t tick = 0; tick < 30; ++tick) stepPair(sender, receiver, tick);
ByteBuffer got;
CHECK(receiver.popReliable(got));
CHECK_EQ(indexOf(got), 0u);
CHECK_EQ(sender.unackedFragmentCount(), static_cast<std::size_t>(0));
// One payload datagram plus at most a handful of bare acks, not one per tick.
CHECK(receiver.stats().datagramsSent <= 3u);
CHECK(sender.stats().datagramsSent <= 3u);
}