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http2: refactor ping + settings object lifetime management

Have clearer ownership relations between the `Http2Ping`,
`Http2Settings` and `Http2Session` objects.

Ping and Settings objects are now owned by the `Http2Session`
instance, and deleted along with it, so neither type of object
refers to the session after it is gone.
In the case of `Http2Ping`s, that deletion is slightly delayed,
so we explicitly reset its `session_` property.

Fixes: #28088

PR-URL: #28150
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ujjwal Sharma <usharma1998@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
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addaleax authored and targos committed Jun 10, 2019
1 parent e517b03 commit d0de204c12a4de4ce6fe598438c5942510328dab
Showing with 111 additions and 55 deletions.
  1. +4 −2 src/base_object-inl.h
  2. +6 −0 src/base_object.h
  3. +58 −45 src/node_http2.cc
  4. +7 −8 src/node_http2.h
  5. +36 −0 test/parallel/test-http2-ping-settings-heapdump.js
@@ -40,9 +40,8 @@ BaseObject::BaseObject(Environment* env, v8::Local<v8::Object> object)
env_->AddCleanupHook(DeleteMe, static_cast<void*>(this));
}


BaseObject::~BaseObject() {
env_->RemoveCleanupHook(DeleteMe, static_cast<void*>(this));
RemoveCleanupHook();

if (persistent_handle_.IsEmpty()) {
// This most likely happened because the weak callback below cleared it.
@@ -55,6 +54,9 @@ BaseObject::~BaseObject() {
}
}

void BaseObject::RemoveCleanupHook() {
env_->RemoveCleanupHook(DeleteMe, static_cast<void*>(this));
}

v8::Global<v8::Object>& BaseObject::persistent() {
return persistent_handle_;
@@ -83,6 +83,12 @@ class BaseObject : public MemoryRetainer {
v8::Local<v8::Value> value,
const v8::PropertyCallbackInfo<void>& info);

protected:
// Can be used to avoid the automatic object deletion when the Environment
// exits, for example when this object is owned and deleted by another
// BaseObject at that point.
inline void RemoveCleanupHook();

private:
v8::Local<v8::Object> WrappedObject() const override;
static void DeleteMe(void* data);
@@ -237,6 +237,7 @@ Http2Session::Http2Settings::Http2Settings(Environment* env,
: AsyncWrap(env, obj, PROVIDER_HTTP2SETTINGS),
session_(session),
startTime_(start_time) {
RemoveCleanupHook(); // This object is owned by the Http2Session.
Init();
}

@@ -311,12 +312,11 @@ void Http2Session::Http2Settings::Done(bool ack) {
uint64_t end = uv_hrtime();
double duration = (end - startTime_) / 1e6;

Local<Value> argv[2] = {
Local<Value> argv[] = {
Boolean::New(env()->isolate(), ack),
Number::New(env()->isolate(), duration)
};
MakeCallback(env()->ondone_string(), arraysize(argv), argv);
delete this;
}

// The Http2Priority class initializes an appropriate nghttp2_priority_spec
@@ -746,11 +746,14 @@ void Http2Session::Close(uint32_t code, bool socket_closed) {
// If there are outstanding pings, those will need to be canceled, do
// so on the next iteration of the event loop to avoid calling out into
// javascript since this may be called during garbage collection.
while (!outstanding_pings_.empty()) {
Http2Session::Http2Ping* ping = PopPing();
env()->SetImmediate([](Environment* env, void* data) {
static_cast<Http2Session::Http2Ping*>(data)->Done(false);
}, static_cast<void*>(ping));
while (std::unique_ptr<Http2Ping> ping = PopPing()) {
ping->DetachFromSession();
env()->SetImmediate(
[](Environment* env, void* data) {
std::unique_ptr<Http2Ping> ping{static_cast<Http2Ping*>(data)};
ping->Done(false);
},
static_cast<void*>(ping.release()));
}

statistics_.end_time = uv_hrtime();
@@ -1435,9 +1438,9 @@ void Http2Session::HandlePingFrame(const nghttp2_frame* frame) {
Local<Value> arg;
bool ack = frame->hd.flags & NGHTTP2_FLAG_ACK;
if (ack) {
Http2Ping* ping = PopPing();
std::unique_ptr<Http2Ping> ping = PopPing();

if (ping == nullptr) {
if (!ping) {
// PING Ack is unsolicited. Treat as a connection error. The HTTP/2
// spec does not require this, but there is no legitimate reason to
// receive an unsolicited PING ack on a connection. Either the peer
@@ -1470,8 +1473,8 @@ void Http2Session::HandleSettingsFrame(const nghttp2_frame* frame) {

// If this is an acknowledgement, we should have an Http2Settings
// object for it.
Http2Settings* settings = PopSettings();
if (settings != nullptr) {
std::unique_ptr<Http2Settings> settings = PopSettings();
if (settings) {
settings->Done(true);
return;
}
@@ -2775,15 +2778,12 @@ void Http2Session::Ping(const FunctionCallbackInfo<Value>& args) {
}
if (obj->Set(env->context(), env->ondone_string(), args[1]).IsNothing())
return;
Http2Session::Http2Ping* ping = new Http2Ping(session, obj);

Http2Ping* ping = session->AddPing(std::make_unique<Http2Ping>(session, obj));
// To prevent abuse, we strictly limit the number of unacknowledged PING
// frames that may be sent at any given time. This is configurable in the
// Options when creating a Http2Session.
if (!session->AddPing(ping)) {
ping->Done(false);
return args.GetReturnValue().Set(false);
}
if (ping == nullptr) return args.GetReturnValue().Set(false);

// The Ping itself is an Async resource. When the acknowledgement is received,
// the callback will be invoked and a notification sent out to JS land. The
@@ -2808,60 +2808,67 @@ void Http2Session::Settings(const FunctionCallbackInfo<Value>& args) {
if (obj->Set(env->context(), env->ondone_string(), args[0]).IsNothing())
return;

Http2Session::Http2Settings* settings =
new Http2Settings(session->env(), session, obj, 0);
if (!session->AddSettings(settings)) {
settings->Done(false);
return args.GetReturnValue().Set(false);
}
Http2Session::Http2Settings* settings = session->AddSettings(
std::make_unique<Http2Settings>(session->env(), session, obj, 0));
if (settings == nullptr) return args.GetReturnValue().Set(false);

settings->Send();
args.GetReturnValue().Set(true);
}


Http2Session::Http2Ping* Http2Session::PopPing() {
Http2Ping* ping = nullptr;
std::unique_ptr<Http2Session::Http2Ping> Http2Session::PopPing() {
std::unique_ptr<Http2Ping> ping;
if (!outstanding_pings_.empty()) {
ping = outstanding_pings_.front();
ping = std::move(outstanding_pings_.front());
outstanding_pings_.pop();
DecrementCurrentSessionMemory(sizeof(*ping));
}
return ping;
}

bool Http2Session::AddPing(Http2Session::Http2Ping* ping) {
if (outstanding_pings_.size() == max_outstanding_pings_)
return false;
outstanding_pings_.push(ping);
Http2Session::Http2Ping* Http2Session::AddPing(
std::unique_ptr<Http2Session::Http2Ping> ping) {
if (outstanding_pings_.size() == max_outstanding_pings_) {
ping->Done(false);
return nullptr;
}
Http2Ping* ptr = ping.get();
outstanding_pings_.emplace(std::move(ping));
IncrementCurrentSessionMemory(sizeof(*ping));
return true;
return ptr;
}

Http2Session::Http2Settings* Http2Session::PopSettings() {
Http2Settings* settings = nullptr;
std::unique_ptr<Http2Session::Http2Settings> Http2Session::PopSettings() {
std::unique_ptr<Http2Settings> settings;
if (!outstanding_settings_.empty()) {
settings = outstanding_settings_.front();
settings = std::move(outstanding_settings_.front());
outstanding_settings_.pop();
DecrementCurrentSessionMemory(sizeof(*settings));
}
return settings;
}

bool Http2Session::AddSettings(Http2Session::Http2Settings* settings) {
if (outstanding_settings_.size() == max_outstanding_settings_)
return false;
outstanding_settings_.push(settings);
Http2Session::Http2Settings* Http2Session::AddSettings(
std::unique_ptr<Http2Session::Http2Settings> settings) {
if (outstanding_settings_.size() == max_outstanding_settings_) {
settings->Done(false);
return nullptr;
}
Http2Settings* ptr = settings.get();
outstanding_settings_.emplace(std::move(settings));
IncrementCurrentSessionMemory(sizeof(*settings));
return true;
return ptr;
}

Http2Session::Http2Ping::Http2Ping(Http2Session* session, Local<Object> obj)
: AsyncWrap(session->env(), obj, AsyncWrap::PROVIDER_HTTP2PING),
session_(session),
startTime_(uv_hrtime()) {}
startTime_(uv_hrtime()) {
RemoveCleanupHook(); // This object is owned by the Http2Session.
}

void Http2Session::Http2Ping::Send(const uint8_t* payload) {
CHECK_NOT_NULL(session_);
uint8_t data[8];
if (payload == nullptr) {
memcpy(&data, &startTime_, arraysize(data));
@@ -2872,8 +2879,12 @@ void Http2Session::Http2Ping::Send(const uint8_t* payload) {
}

void Http2Session::Http2Ping::Done(bool ack, const uint8_t* payload) {
session_->statistics_.ping_rtt = uv_hrtime() - startTime_;
double duration = session_->statistics_.ping_rtt / 1e6;
uint64_t duration_ns = uv_hrtime() - startTime_;
double duration_ms = duration_ns / 1e6;
if (session_ != nullptr) session_->statistics_.ping_rtt = duration_ns;

HandleScope handle_scope(env()->isolate());
Context::Scope context_scope(env()->context());

Local<Value> buf = Undefined(env()->isolate());
if (payload != nullptr) {
@@ -2882,15 +2893,17 @@ void Http2Session::Http2Ping::Done(bool ack, const uint8_t* payload) {
8).ToLocalChecked();
}

Local<Value> argv[3] = {
Local<Value> argv[] = {
Boolean::New(env()->isolate(), ack),
Number::New(env()->isolate(), duration),
Number::New(env()->isolate(), duration_ms),
buf
};
MakeCallback(env()->ondone_string(), arraysize(argv), argv);
delete this;
}

void Http2Session::Http2Ping::DetachFromSession() {
session_ = nullptr;
}

void nghttp2_stream_write::MemoryInfo(MemoryTracker* tracker) const {
if (req_wrap != nullptr)
@@ -803,11 +803,11 @@ class Http2Session : public AsyncWrap, public StreamListener {
return env()->event_loop();
}

Http2Ping* PopPing();
bool AddPing(Http2Ping* ping);
std::unique_ptr<Http2Ping> PopPing();
Http2Ping* AddPing(std::unique_ptr<Http2Ping> ping);

Http2Settings* PopSettings();
bool AddSettings(Http2Settings* settings);
std::unique_ptr<Http2Settings> PopSettings();
Http2Settings* AddSettings(std::unique_ptr<Http2Settings> settings);

void IncrementCurrentSessionMemory(uint64_t amount) {
current_session_memory_ += amount;
@@ -976,10 +976,10 @@ class Http2Session : public AsyncWrap, public StreamListener {
v8::Local<v8::ArrayBuffer> stream_buf_ab_;

size_t max_outstanding_pings_ = DEFAULT_MAX_PINGS;
std::queue<Http2Ping*> outstanding_pings_;
std::queue<std::unique_ptr<Http2Ping>> outstanding_pings_;

size_t max_outstanding_settings_ = DEFAULT_MAX_SETTINGS;
std::queue<Http2Settings*> outstanding_settings_;
std::queue<std::unique_ptr<Http2Settings>> outstanding_settings_;

std::vector<nghttp2_stream_write> outgoing_buffers_;
std::vector<uint8_t> outgoing_storage_;
@@ -1086,12 +1086,11 @@ class Http2Session::Http2Ping : public AsyncWrap {

void Send(const uint8_t* payload);
void Done(bool ack, const uint8_t* payload = nullptr);
void DetachFromSession();

private:
Http2Session* session_;
uint64_t startTime_;

friend class Http2Session;
};

// The Http2Settings class is used to parse the settings passed in for
@@ -0,0 +1,36 @@
'use strict';
const common = require('../common');
if (!common.hasCrypto)
common.skip('missing crypto');

const http2 = require('http2');
const v8 = require('v8');

// Regression test for https://github.com/nodejs/node/issues/28088:
// Verify that Http2Settings and Http2Ping objects don't reference the session
// after it is destroyed, either because they are detached from it or have been
// destroyed themselves.

for (const variant of ['ping', 'settings']) {
const server = http2.createServer();
server.on('session', common.mustCall((session) => {
if (variant === 'ping') {
session.ping(common.expectsError({
code: 'ERR_HTTP2_PING_CANCEL'
}));
} else {
session.settings(undefined, common.mustNotCall());
}

session.on('close', common.mustCall(() => {
v8.getHeapSnapshot().resume();
server.close();
}));
session.destroy();
}));

server.listen(0, common.mustCall(() => {
http2.connect(`http://localhost:${server.address().port}`,
common.mustCall());
}));
}

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