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endpoint.cc
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1367 lines (1182 loc) · 47.7 KB
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#if HAVE_OPENSSL && NODE_OPENSSL_HAS_QUIC
#include "endpoint.h"
#include <aliased_struct-inl.h>
#include <async_wrap-inl.h>
#include <env-inl.h>
#include <memory_tracker-inl.h>
#include <ngtcp2/ngtcp2.h>
#include <node_errors.h>
#include <node_sockaddr-inl.h>
#include <req_wrap-inl.h>
#include <util-inl.h>
#include <uv.h>
#include <v8.h>
#include "application.h"
#include "defs.h"
namespace node {
using v8::ArrayBufferView;
using v8::BackingStore;
using v8::FunctionCallbackInfo;
using v8::FunctionTemplate;
using v8::HandleScope;
using v8::Int32;
using v8::Integer;
using v8::Just;
using v8::Local;
using v8::Maybe;
using v8::Nothing;
using v8::Number;
using v8::Object;
using v8::PropertyAttribute;
using v8::String;
using v8::Value;
namespace quic {
#define ENDPOINT_STATE(V) \
/* Bound to the UDP port */ \
V(BOUND, bound, uint8_t) \
/* Receiving packets on the UDP port */ \
V(RECEIVING, receiving, uint8_t) \
/* Listening as a QUIC server */ \
V(LISTENING, listening, uint8_t) \
/* In the process of closing down */ \
V(CLOSING, closing, uint8_t) \
/* In the process of closing down, waiting for pending send callbacks */ \
V(WAITING_FOR_CALLBACKS, waiting_for_callbacks, uint8_t) \
/* Temporarily paused serving new initial requests */ \
V(BUSY, busy, uint8_t) \
/* The number of pending send callbacks */ \
V(PENDING_CALLBACKS, pending_callbacks, size_t)
#define ENDPOINT_STATS(V) \
V(CREATED_AT, created_at) \
V(DESTROYED_AT, destroyed_at) \
V(BYTES_RECEIVED, bytes_received) \
V(BYTES_SENT, bytes_sent) \
V(PACKETS_RECEIVED, packets_received) \
V(PACKETS_SENT, packets_sent) \
V(SERVER_SESSIONS, server_sessions) \
V(CLIENT_SESSIONS, client_sessions) \
V(SERVER_BUSY_COUNT, server_busy_count) \
V(RETRY_COUNT, retry_count) \
V(VERSION_NEGOTIATION_COUNT, version_negotiation_count) \
V(STATELESS_RESET_COUNT, stateless_reset_count) \
V(IMMEDIATE_CLOSE_COUNT, immediate_close_count)
struct Endpoint::State {
#define V(_, name, type) type name;
ENDPOINT_STATE(V)
#undef V
};
STAT_STRUCT(Endpoint, ENDPOINT)
// ============================================================================
namespace {
#ifdef DEBUG
bool is_diagnostic_packet_loss(double probability) {
if (LIKELY(probability == 0.0)) return false;
unsigned char c = 255;
CHECK(crypto::CSPRNG(&c, 1).is_ok());
return (static_cast<double>(c) / 255) < probability;
}
#endif // DEBUG
template <typename Opt, ngtcp2_cc_algo Opt::*member>
bool SetOption(Environment* env,
Opt* options,
const v8::Local<v8::Object>& object,
const v8::Local<v8::String>& name) {
v8::Local<v8::Value> value;
if (!object->Get(env->context(), name).ToLocal(&value)) return false;
if (!value->IsUndefined()) {
int num = value.As<Int32>()->Value();
switch (num) {
case NGTCP2_CC_ALGO_RENO:
[[fallthrough]];
case NGTCP2_CC_ALGO_CUBIC:
[[fallthrough]];
case NGTCP2_CC_ALGO_BBR:
[[fallthrough]];
case NGTCP2_CC_ALGO_BBR2:
break;
default:
THROW_ERR_INVALID_ARG_VALUE(env, "The cc_algorithm is invalid");
return false;
}
options->*member = static_cast<ngtcp2_cc_algo>(num);
}
return true;
}
template <typename Opt, double Opt::*member>
bool SetOption(Environment* env,
Opt* options,
const v8::Local<v8::Object>& object,
const v8::Local<v8::String>& name) {
v8::Local<v8::Value> value;
if (!object->Get(env->context(), name).ToLocal(&value)) return false;
if (!value->IsUndefined()) {
CHECK(value->IsNumber());
options->*member = value.As<Number>()->Value();
}
return true;
}
template <typename Opt, uint32_t Opt::*member>
bool SetOption(Environment* env,
Opt* options,
const v8::Local<v8::Object>& object,
const v8::Local<v8::String>& name) {
v8::Local<v8::Value> value;
if (!object->Get(env->context(), name).ToLocal(&value)) return false;
if (!value->IsUndefined()) {
CHECK(value->IsNumber());
options->*member = value.As<Int32>()->Value();
}
return true;
}
template <typename Opt, uint8_t Opt::*member>
bool SetOption(Environment* env,
Opt* options,
const v8::Local<v8::Object>& object,
const v8::Local<v8::String>& name) {
v8::Local<v8::Value> value;
if (!object->Get(env->context(), name).ToLocal(&value)) return false;
if (!value->IsUndefined()) {
CHECK(value->IsNumber());
options->*member = value.As<Int32>()->Value();
}
return true;
}
template <typename Opt, TokenSecret Opt::*member>
bool SetOption(Environment* env,
Opt* options,
const v8::Local<v8::Object>& object,
const v8::Local<v8::String>& name) {
v8::Local<v8::Value> value;
if (!object->Get(env->context(), name).ToLocal(&value)) return false;
if (!value->IsUndefined()) {
CHECK(value->IsArrayBufferView());
Store store(value.As<ArrayBufferView>());
CHECK_EQ(store.length(), TokenSecret::QUIC_TOKENSECRET_LEN);
ngtcp2_vec buf = store;
options->*member = buf.base;
}
return true;
}
} // namespace
Maybe<Endpoint::Options> Endpoint::Options::From(Environment* env,
Local<Value> value) {
if (value.IsEmpty() || !value->IsObject()) {
THROW_ERR_INVALID_ARG_TYPE(env, "options must be an object");
return Nothing<Options>();
}
auto& state = BindingData::Get(env);
auto params = value.As<Object>();
Options options;
#define SET(name) \
SetOption<Endpoint::Options, &Endpoint::Options::name>( \
env, &options, params, state.name##_string())
if (!SET(retry_token_expiration) || !SET(token_expiration) ||
!SET(max_connections_per_host) || !SET(max_connections_total) ||
!SET(max_stateless_resets) || !SET(address_lru_size) ||
!SET(max_retries) || !SET(max_payload_size) ||
!SET(unacknowledged_packet_threshold) || !SET(validate_address) ||
!SET(disable_stateless_reset) || !SET(ipv6_only) ||
#ifdef DEBUG
!SET(rx_loss) || !SET(tx_loss) ||
#endif
!SET(cc_algorithm) || !SET(udp_receive_buffer_size) ||
!SET(udp_send_buffer_size) || !SET(udp_ttl) || !SET(reset_token_secret) ||
!SET(token_secret)) {
return Nothing<Options>();
}
return Just<Options>(options);
#undef SET
}
void Endpoint::Options::MemoryInfo(MemoryTracker* tracker) const {
tracker->TrackField("reset_token_secret", reset_token_secret);
tracker->TrackField("token_secret", token_secret);
}
// ======================================================================================
// Endpoint::UDP and Endpoint::UDP::Impl
class Endpoint::UDP::Impl final : public HandleWrap {
public:
static Local<FunctionTemplate> GetConstructorTemplate(Environment* env) {
auto& state = BindingData::Get(env);
auto tmpl = state.udp_constructor_template();
if (tmpl.IsEmpty()) {
tmpl = NewFunctionTemplate(env->isolate(), IllegalConstructor);
tmpl->Inherit(HandleWrap::GetConstructorTemplate(env));
tmpl->InstanceTemplate()->SetInternalFieldCount(
HandleWrap::kInternalFieldCount);
tmpl->SetClassName(state.endpoint_udp_string());
state.set_udp_constructor_template(tmpl);
}
return tmpl;
}
static BaseObjectPtr<Impl> Create(Endpoint* endpoint) {
Local<Object> obj;
if (!GetConstructorTemplate(endpoint->env())
->InstanceTemplate()
->NewInstance(endpoint->env()->context())
.ToLocal(&obj)) {
return BaseObjectPtr<Impl>();
}
return MakeDetachedBaseObject<Impl>(endpoint, obj);
}
static Impl* From(uv_udp_t* handle) {
return ContainerOf(&Impl::handle_, handle);
}
static Impl* From(uv_handle_t* handle) {
return From(reinterpret_cast<uv_udp_t*>(handle));
}
Impl(Endpoint* endpoint, Local<Object> object)
: HandleWrap(endpoint->env(),
object,
reinterpret_cast<uv_handle_t*>(&handle_),
AsyncWrap::PROVIDER_QUIC_UDP),
endpoint_(endpoint) {
CHECK_EQ(uv_udp_init(endpoint->env()->event_loop(), &handle_), 0);
handle_.data = this;
}
SET_NO_MEMORY_INFO()
SET_MEMORY_INFO_NAME(Endpoint::UDP::Impl)
SET_SELF_SIZE(Impl)
private:
static void ClosedCb(uv_handle_t* handle) {
std::unique_ptr<Impl> ptr(From(handle));
}
static void OnAlloc(uv_handle_t* handle,
size_t suggested_size,
uv_buf_t* buf) {
*buf = From(handle)->env()->allocate_managed_buffer(suggested_size);
}
static void OnReceive(uv_udp_t* handle,
ssize_t nread,
const uv_buf_t* buf,
const sockaddr* addr,
unsigned int flags) {
// Nothing to do in these cases. Specifically, if the nread
// is zero or we've received a partial packet, we're just
// going to ignore it.
if (nread == 0 || flags & UV_UDP_PARTIAL) return;
auto impl = From(handle);
DCHECK_NOT_NULL(impl);
DCHECK_NOT_NULL(impl->endpoint_);
if (nread < 0) {
impl->endpoint_->Destroy(CloseContext::RECEIVE_FAILURE,
static_cast<int>(nread));
return;
}
impl->endpoint_->Receive(uv_buf_init(buf->base, static_cast<size_t>(nread)),
SocketAddress(addr));
}
uv_udp_t handle_;
Endpoint* endpoint_;
friend class UDP;
};
Endpoint::UDP::UDP(Endpoint* endpoint) : impl_(Impl::Create(endpoint)) {
endpoint->env()->AddCleanupHook(CleanupHook, this);
}
Endpoint::UDP::~UDP() {
Close();
}
int Endpoint::UDP::Bind(const Endpoint::Options& options) {
if (is_bound_) return UV_EALREADY;
if (is_closed() || impl_->IsHandleClosing()) return UV_EBADF;
int flags = 0;
if (options.local_address.family() == AF_INET6 && options.ipv6_only)
flags |= UV_UDP_IPV6ONLY;
int err = uv_udp_bind(&impl_->handle_, options.local_address.data(), flags);
int size;
if (!err) {
is_bound_ = true;
size = static_cast<int>(options.udp_receive_buffer_size);
if (size > 0) {
err = uv_recv_buffer_size(reinterpret_cast<uv_handle_t*>(&impl_->handle_),
&size);
if (err) return err;
}
size = static_cast<int>(options.udp_send_buffer_size);
if (size > 0) {
err = uv_send_buffer_size(reinterpret_cast<uv_handle_t*>(&impl_->handle_),
&size);
if (err) return err;
}
size = static_cast<int>(options.udp_ttl);
if (size > 0) {
err = uv_udp_set_ttl(&impl_->handle_, size);
if (err) return err;
}
}
return err;
}
void Endpoint::UDP::Ref() {
if (!is_closed()) uv_ref(reinterpret_cast<uv_handle_t*>(&impl_->handle_));
}
void Endpoint::UDP::Unref() {
if (!is_closed()) uv_unref(reinterpret_cast<uv_handle_t*>(&impl_->handle_));
}
int Endpoint::UDP::Start() {
if (is_closed() || impl_->IsHandleClosing()) return UV_EBADF;
if (is_started_) return 0;
int err = uv_udp_recv_start(&impl_->handle_, Impl::OnAlloc, Impl::OnReceive);
is_started_ = (err == 0);
return err;
}
void Endpoint::UDP::Stop() {
if (is_closed() || impl_->IsHandleClosing() || !is_started_) return;
USE(uv_udp_recv_stop(&impl_->handle_));
is_started_ = false;
}
void Endpoint::UDP::Close() {
if (is_closed() || impl_->IsHandleClosing()) return;
Stop();
is_bound_ = false;
impl_->env()->RemoveCleanupHook(CleanupHook, this);
impl_->Close();
impl_.reset();
}
bool Endpoint::UDP::is_bound() const {
return is_bound_;
}
bool Endpoint::UDP::is_closed() const {
return !impl_;
}
Endpoint::UDP::operator bool() const {
return !impl_;
}
SocketAddress Endpoint::UDP::local_address() const {
CHECK(!is_closed() && is_bound());
return SocketAddress::FromSockName(impl_->handle_);
}
int Endpoint::UDP::Send(BaseObjectPtr<Packet> packet) {
if (is_closed() || impl_->IsHandleClosing()) return UV_EBADF;
CHECK(packet && !packet->is_sending());
uv_buf_t buf = *packet;
return packet->Dispatch(
uv_udp_send,
&impl_->handle_,
&buf,
1,
packet->destination().data(),
uv_udp_send_cb{[](uv_udp_send_t* req, int status) {
auto ptr = static_cast<Packet*>(ReqWrap<uv_udp_send_t>::from_req(req));
ptr->Done(status);
}});
}
void Endpoint::UDP::MemoryInfo(MemoryTracker* tracker) const {
if (impl_) tracker->TrackField("impl", impl_);
}
void Endpoint::UDP::CleanupHook(void* data) {
static_cast<UDP*>(data)->Close();
}
// ============================================================================
bool Endpoint::HasInstance(Environment* env, Local<Value> value) {
return GetConstructorTemplate(env)->HasInstance(value);
}
Local<FunctionTemplate> Endpoint::GetConstructorTemplate(Environment* env) {
auto& state = BindingData::Get(env);
auto tmpl = state.endpoint_constructor_template();
if (tmpl.IsEmpty()) {
auto isolate = env->isolate();
tmpl = NewFunctionTemplate(isolate, IllegalConstructor);
tmpl->Inherit(AsyncWrap::GetConstructorTemplate(env));
tmpl->SetClassName(state.endpoint_string());
tmpl->InstanceTemplate()->SetInternalFieldCount(
Endpoint::kInternalFieldCount);
SetProtoMethod(isolate, tmpl, "listen", DoListen);
SetProtoMethod(isolate, tmpl, "closeGracefully", DoCloseGracefully);
SetProtoMethod(isolate, tmpl, "connect", DoConnect);
SetProtoMethod(isolate, tmpl, "markBusy", MarkBusy);
SetProtoMethod(isolate, tmpl, "ref", Ref);
SetProtoMethod(isolate, tmpl, "unref", Unref);
SetProtoMethodNoSideEffect(isolate, tmpl, "address", LocalAddress);
state.set_endpoint_constructor_template(tmpl);
}
return tmpl;
}
void Endpoint::Initialize(Environment* env, Local<Object> target) {
SetMethod(env->context(), target, "createEndpoint", CreateEndpoint);
#define V(name, _) IDX_STATS_ENDPOINT_##name,
enum EndpointStatsIdx { ENDPOINT_STATS(V) IDX_STATS_ENDPOINT_COUNT };
#undef V
#define V(name, key, __) \
auto IDX_STATE_ENDPOINT_##name = offsetof(Endpoint::State, key);
ENDPOINT_STATE(V)
#undef V
#define V(name, _) NODE_DEFINE_CONSTANT(target, IDX_STATS_ENDPOINT_##name);
ENDPOINT_STATS(V)
#undef V
#define V(name, _, __) NODE_DEFINE_CONSTANT(target, IDX_STATE_ENDPOINT_##name);
ENDPOINT_STATE(V)
#undef V
}
void Endpoint::RegisterExternalReferences(ExternalReferenceRegistry* registry) {
registry->Register(CreateEndpoint);
registry->Register(DoConnect);
registry->Register(DoListen);
registry->Register(DoCloseGracefully);
registry->Register(LocalAddress);
registry->Register(Ref);
registry->Register(Unref);
}
BaseObjectPtr<Endpoint> Endpoint::Create(Environment* env,
const Endpoint::Options& options) {
Local<Object> obj;
if (!GetConstructorTemplate(env)
->InstanceTemplate()
->NewInstance(env->context())
.ToLocal(&obj)) {
return BaseObjectPtr<Endpoint>();
}
return MakeDetachedBaseObject<Endpoint>(env, obj, options);
}
Endpoint::Endpoint(Environment* env,
Local<Object> object,
const Endpoint::Options& options)
: AsyncWrap(env, object, AsyncWrap::PROVIDER_QUIC_ENDPOINT),
stats_(env->isolate()),
state_(env->isolate()),
options_(std::move(options)),
udp_(this),
addrLRU_(options_.address_lru_size) {
MakeWeak();
const auto defineProperty = [&](auto name, auto value) {
object
->DefineOwnProperty(
env->context(), name, value, PropertyAttribute::ReadOnly)
.Check();
};
defineProperty(env->state_string(), state_.GetArrayBuffer());
defineProperty(env->stats_string(), stats_.GetArrayBuffer());
}
Endpoint::~Endpoint() {
udp_.Close();
DCHECK_EQ(state_->pending_callbacks, 0);
DCHECK(sessions_.empty());
DCHECK(is_closed());
}
SocketAddress Endpoint::local_address() const {
CHECK(!is_closed());
return udp_.local_address();
}
void Endpoint::MarkAsBusy(bool on) {
state_->busy = on ? 1 : 0;
}
RegularToken Endpoint::GenerateNewToken(uint32_t version,
const SocketAddress& remote_address) {
DCHECK(!is_closed() && !is_closing());
return RegularToken(version, remote_address, options_.token_secret);
}
StatelessResetToken Endpoint::GenerateNewStatelessResetToken(
uint8_t* token, const CID& cid) const {
DCHECK(!is_closed() && !is_closing());
return StatelessResetToken(token, options_.reset_token_secret, cid);
}
void Endpoint::AddSession(const CID& cid, BaseObjectPtr<Session> session) {
if (is_closed() || is_closing()) return;
sessions_[cid] = session;
IncrementSocketAddressCounter(session->remote_address());
if (session->is_server()) {
STAT_INCREMENT(Stats, server_sessions);
} else {
STAT_INCREMENT(Stats, client_sessions);
}
if (session->is_server()) EmitNewSession(session);
}
void Endpoint::RemoveSession(const CID& cid) {
if (is_closed()) return;
auto session = FindSession(cid);
if (!session) return;
DecrementSocketAddressCounter(session->remote_address());
sessions_.erase(cid);
if (state_->waiting_for_callbacks == 1) MaybeDestroy();
}
BaseObjectPtr<Session> Endpoint::FindSession(const CID& cid) {
BaseObjectPtr<Session> session;
auto session_it = sessions_.find(cid);
if (session_it == std::end(sessions_)) {
auto scid_it = dcid_to_scid_.find(cid);
if (scid_it != std::end(dcid_to_scid_)) {
session_it = sessions_.find(scid_it->second);
CHECK_NE(session_it, std::end(sessions_));
session = session_it->second;
}
} else {
session = session_it->second;
}
return session;
}
void Endpoint::AssociateCID(const CID& cid, const CID& scid) {
if (!is_closed() && !is_closing() && cid && scid && cid != scid &&
dcid_to_scid_[cid] != scid) {
dcid_to_scid_.emplace(cid, scid);
}
}
void Endpoint::DisassociateCID(const CID& cid) {
if (!is_closed() && cid) dcid_to_scid_.erase(cid);
}
void Endpoint::AssociateStatelessResetToken(const StatelessResetToken& token,
Session* session) {
if (is_closed() || is_closing()) return;
token_map_[token] = session;
}
void Endpoint::DisassociateStatelessResetToken(
const StatelessResetToken& token) {
if (!is_closed()) token_map_.erase(token);
}
void Endpoint::Send(BaseObjectPtr<Packet> packet) {
#ifdef DEBUG
// When diagnostic packet loss is enabled, the packet will be randomly
// dropped. This can happen to any type of packet. We use this only in
// testing to test various reliability issues.
if (UNLIKELY(is_diagnostic_packet_loss(options_.tx_loss))) {
packet->Done(0);
// Simulating tx packet loss
return;
}
#endif // DEBUG
if (is_closed() || is_closing() || packet->length() == 0) return;
state_->pending_callbacks++;
int err = udp_.Send(packet);
if (err != 0) {
packet->Done(err);
Destroy(CloseContext::SEND_FAILURE, err);
}
STAT_INCREMENT_N(Stats, bytes_sent, packet->length());
STAT_INCREMENT(Stats, packets_sent);
}
void Endpoint::SendRetry(const PathDescriptor& options) {
// Generating and sending retry packets does consume some system resources,
// and it is possible for a malicious peer to trigger sending a large number
// of retry packets, resulting in a potential DOS vector. To help ward that
// off, we track how many retry packets we send to a particular host and
// enforce limits. Note that since we are using an LRU cache these limits
// aren't strict. If a retry is sent, we increment the retry_count statistic
// to give application code a means of detecting and responding to abuse on
// its own. What this count does not give is the rate of retry, so it is still
// somewhat limited.
auto info = addrLRU_.Upsert(options.remote_address);
if (++(info->retry_count) <= options_.max_retries) {
auto packet =
Packet::CreateRetryPacket(env(), this, options, options_.token_secret);
if (packet) {
STAT_INCREMENT(Stats, retry_count);
Send(std::move(packet));
}
// If creating the retry is unsuccessful, we just drop things on the floor.
// It's not worth committing any further resources to this one packet. We
// might want to log the failure at some point tho.
}
}
void Endpoint::SendVersionNegotiation(const PathDescriptor& options) {
// While creating and sending a version negotiation packet does consume a
// small amount of system resources, and while it is fairly trivial for a
// malicious peer to force a version negotiation to be sent, these are more
// trivial to create than the cryptographically generated retry and stateless
// reset packets. If the packet is sent, then we'll at least increment the
// version_negotiation_count statistic so that application code can keep an
// eye on it.
auto packet = Packet::CreateVersionNegotiationPacket(env(), this, options);
if (packet) {
STAT_INCREMENT(Stats, version_negotiation_count);
Send(std::move(packet));
}
// If creating the packet is unsuccessful, we just drop things on the floor.
// It's not worth committing any further resources to this one packet. We
// might want to log the failure at some point tho.
}
bool Endpoint::SendStatelessReset(const PathDescriptor& options,
size_t source_len) {
if (UNLIKELY(options_.disable_stateless_reset)) return false;
const auto exceeds_limits = [&] {
SocketAddressInfoTraits::Type* counts =
addrLRU_.Peek(options.remote_address);
auto count = counts != nullptr ? counts->reset_count : 0;
return count >= options_.max_stateless_resets;
};
// Per the QUIC spec, we need to protect against sending too many stateless
// reset tokens to an endpoint to prevent endless looping.
if (exceeds_limits()) return false;
auto packet = Packet::CreateStatelessResetPacket(
env(), this, options, options_.reset_token_secret, source_len);
if (packet) {
addrLRU_.Upsert(options.remote_address)->reset_count++;
STAT_INCREMENT(Stats, stateless_reset_count);
Send(std::move(packet));
return true;
}
return false;
}
void Endpoint::SendImmediateConnectionClose(const PathDescriptor& options,
QuicError reason) {
// While it is possible for a malicious peer to cause us to create a large
// number of these, generating them is fairly trivial.
auto packet = Packet::CreateImmediateConnectionClosePacket(
env(), this, options, reason);
if (packet) {
STAT_INCREMENT(Stats, immediate_close_count);
Send(std::move(packet));
}
}
bool Endpoint::Start() {
if (is_closed() || is_closing()) return false;
if (state_->receiving == 1) return true;
int err = 0;
if (state_->bound == 0) {
err = udp_.Bind(options_);
if (err != 0) {
// If we failed to bind, destroy the endpoint. There's nothing we can do.
Destroy(CloseContext::BIND_FAILURE, err);
return false;
}
state_->bound = 1;
}
err = udp_.Start();
if (err != 0) {
// If we failed to start listening, destroy the endpoint. There's nothing we
// can do.
Destroy(CloseContext::START_FAILURE, err);
return false;
}
BindingData::Get(env()).listening_endpoints[this] =
BaseObjectPtr<Endpoint>(this);
state_->receiving = 1;
return true;
}
void Endpoint::Listen(const Session::Options& options) {
if (is_closed() || is_closing() || state_->listening == 1) return;
server_options_ = options;
if (Start()) state_->listening = 1;
}
BaseObjectPtr<Session> Endpoint::Connect(
const SocketAddress& remote_address,
const Session::Options& options,
std::optional<SessionTicket> session_ticket) {
// If starting fails, the endpoint will be destroyed.
if (!Start()) return BaseObjectPtr<Session>();
auto config = Session::Config(
*this, options, local_address(), remote_address, session_ticket);
auto session = Session::Create(BaseObjectPtr<Endpoint>(this), config);
if (!session) return BaseObjectPtr<Session>();
session->set_wrapped();
session->application().SendPendingData();
return BaseObjectPtr<Session>();
}
void Endpoint::MaybeDestroy() {
if (!is_closing() && sessions_.empty() && state_->pending_callbacks == 0 &&
state_->listening == 0) {
Destroy();
}
}
void Endpoint::Destroy(CloseContext context, int status) {
if (is_closed() || is_closing()) return;
STAT_RECORD_TIMESTAMP(Stats, destroyed_at);
state_->closing = 1;
state_->listening = 0;
close_context_ = context;
close_status_ = status;
// If there are open sessions still, shut them down. As those clean themselves
// up, they will remove themselves. The cleanup here will be synchronous and
// no attempt will be made to communicate further with the peer.
// Intentionally copy the sessions map so that we can safely iterate over it
// while those clean themselves up.
auto sessions = sessions_;
for (auto& session : sessions)
session.second->Close(Session::CloseMethod::SILENT);
sessions.clear();
CHECK(sessions_.empty());
token_map_.clear();
dcid_to_scid_.clear();
udp_.Close();
state_->closing = 0;
state_->bound = 0;
state_->receiving = 0;
BindingData::Get(env()).listening_endpoints.erase(this);
EmitClose(close_context_, close_status_);
}
void Endpoint::CloseGracefully() {
if (!is_closed() && !is_closing() && state_->waiting_for_callbacks == 0) {
state_->listening = 0;
state_->waiting_for_callbacks = 1;
}
// Maybe we can go ahead and destroy now?
MaybeDestroy();
}
void Endpoint::Receive(const uv_buf_t& buf,
const SocketAddress& remote_address) {
const auto receive = [&](Store&& store,
const SocketAddress& local_address,
const SocketAddress& remote_address,
const CID& dcid,
const CID& scid) {
STAT_INCREMENT_N(Stats, bytes_received, store.length());
auto session = FindSession(dcid);
return session && !session->is_destroyed()
? session->Receive(
std::move(store), local_address, remote_address)
: false;
};
const auto accept = [&](const Session::Config& config, Store&& store) {
if (is_closed() || is_closing() || !is_listening()) return false;
auto session = Session::Create(BaseObjectPtr<Endpoint>(this), config);
return session ? session->Receive(std::move(store),
config.local_address,
config.remote_address)
: false;
};
const auto acceptInitialPacket = [&](const uint32_t version,
const CID& dcid,
const CID& scid,
Store&& store,
const SocketAddress& local_address,
const SocketAddress& remote_address) {
// Conditionally accept an initial packet to create a new session.
// If we're not listening, do not accept.
if (state_->listening == 0) return false;
ngtcp2_pkt_hd hd;
// This is our first condition check... A minimal check to see if ngtcp2 can
// even recognize this packet as a quic packet with the correct version.
ngtcp2_vec vec = store;
switch (ngtcp2_accept(&hd, vec.base, vec.len)) {
case 1:
// The requested QUIC protocol version is not supported
SendVersionNegotiation(
PathDescriptor{version, dcid, scid, local_address, remote_address});
// The packet was successfully processed, even if we did refuse the
// connection and send a version negotiation in response.
return true;
case -1:
// The packet is invalid and we're just going to ignore it.
return false;
}
// This is the second condition check... If the server has been marked busy
// or the remote peer has exceeded their maximum number of concurrent
// connections, any new connections will be shut down immediately.
const auto limits_exceeded = [&] {
if (sessions_.size() >= options_.max_connections_total) return true;
SocketAddressInfoTraits::Type* counts = addrLRU_.Peek(remote_address);
auto count = counts != nullptr ? counts->active_connections : 0;
return count >= options_.max_connections_per_host;
};
if (state_->busy || limits_exceeded()) {
// Endpoint is busy or the connection count is exceeded. The connection is
// refused.
if (state_->busy) STAT_INCREMENT(Stats, server_busy_count);
SendImmediateConnectionClose(
PathDescriptor{version, scid, dcid, local_address, remote_address},
QuicError::ForTransport(NGTCP2_CONNECTION_REFUSED));
// The packet was successfully processed, even if we did refuse the
// connection.
return true;
}
// At this point, we start to set up the configuration for our local
// session. The second argument to the Config constructor here is the dcid.
// We pass the received scid here as the value because that is the value
// *this* session will use as it's outbound dcid.
auto config = Session::Config(Side::SERVER,
*this,
server_options_.value(),
version,
local_address,
remote_address,
scid,
dcid);
// The this point, the config.scid and config.dcid represent *our* views of
// the CIDs. Specifically, config.dcid identifies the peer and config.scid
// identifies us. config.dcid should equal scid. config.scid should *not*
// equal dcid.
const auto is_remote_address_validated = [&] {
auto info = addrLRU_.Peek(remote_address);
return info != nullptr ? info->validated : false;
};
// QUIC has address validation built in to the handshake but allows for
// an additional explicit validation request using RETRY frames. If we
// are using explicit validation, we check for the existence of a valid
// token in the packet. If one does not exist, we send a retry with
// a new token. If it does exist, and if it's valid, we grab the original
// cid and continue.
if (!is_remote_address_validated()) {
switch (hd.type) {
case NGTCP2_PKT_INITIAL:
// First, let's see if we need to do anything here.
if (options_.validate_address) {
// If there is no token, generate and send one.
if (hd.token.len == 0) {
SendRetry(PathDescriptor{
version,
dcid,
scid,
local_address,
remote_address,
});
// We still consider this a successfully handled packet even
// if we send a retry.
return true;
}
// We have two kinds of tokens, each prefixed with a different magic
// byte.
switch (hd.token.base[0]) {
case RetryToken::kTokenMagic: {
RetryToken token(hd.token.base, hd.token.len);
auto ocid = token.Validate(
version,
remote_address,
dcid,
options_.token_secret,
options_.retry_token_expiration * NGTCP2_SECONDS);
if (ocid == std::nullopt) {
// Invalid retry token was detected. Close the connection.
SendImmediateConnectionClose(
PathDescriptor{
version, scid, dcid, local_address, remote_address},
QuicError::ForTransport(NGTCP2_CONNECTION_REFUSED));
// We still consider this a successfully handled packet even
// if we send a connection close.
return true;
}
// The ocid is the original dcid that was encoded into the
// original retry packet sent to the client. We use it for
// validation.
config.ocid = ocid.value();
config.retry_scid = dcid;
break;
}
case RegularToken::kTokenMagic: {
RegularToken token(hd.token.base, hd.token.len);
if (!token.Validate(
version,
remote_address,
options_.token_secret,
options_.token_expiration * NGTCP2_SECONDS)) {
SendRetry(PathDescriptor{
version,
dcid,
scid,
local_address,
remote_address,
});
// We still consider this to be a successfully handled packet
// if a retry is sent.
return true;
}
hd.token.base = nullptr;
hd.token.len = 0;
break;
}
default: {
SendRetry(PathDescriptor{
version,
dcid,
scid,
local_address,
remote_address,