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http2: add altsvc support
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Add support for sending and receiving ALTSVC frames.

Backport-PR-URL: #18050
PR-URL: #17917
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
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jasnell authored and MylesBorins committed Jan 10, 2018
1 parent e7a727e commit 9ad7a9a
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10 changes: 10 additions & 0 deletions doc/api/errors.md
Original file line number Diff line number Diff line change
Expand Up @@ -763,6 +763,16 @@ that.

Occurs with multiple attempts to shutdown an HTTP/2 session.

<a id="ERR_HTTP2_ALTSVC_INVALID_ORIGIN"></a>
### ERR_HTTP2_ALTSVC_INVALID_ORIGIN

HTTP/2 ALTSVC frames require a valid origin.

<a id="ERR_HTTP2_ALTSVC_LENGTH"></a>
### ERR_HTTP2_ALTSVC_LENGTH

HTTP/2 ALTSVC frames are limited to a maximum of 16,382 payload bytes.

<a id="ERR_HTTP2_CONNECT_AUTHORITY"></a>
### ERR_HTTP2_CONNECT_AUTHORITY

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94 changes: 94 additions & 0 deletions doc/api/http2.md
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Expand Up @@ -558,11 +558,103 @@ added: REPLACEME
Calls [`unref()`][`net.Socket.prototype.unref`] on this `Http2Session`
instance's underlying [`net.Socket`].

### Class: ServerHttp2Session
<!-- YAML
added: v8.4.0
-->

#### serverhttp2session.altsvc(alt, originOrStream)
<!-- YAML
added: REPLACEME
-->

* `alt` {string} A description of the alternative service configuration as
defined by [RFC 7838][].
* `originOrStream` {number|string|URL|Object} Either a URL string specifying
the origin (or an Object with an `origin` property) or the numeric identifier
of an active `Http2Stream` as given by the `http2stream.id` property.

Submits an `ALTSVC` frame (as defined by [RFC 7838][]) to the connected client.

```js
const http2 = require('http2');

const server = http2.createServer();
server.on('session', (session) => {
// Set altsvc for origin https://example.org:80
session.altsvc('h2=":8000"', 'https://example.org:80');
});

server.on('stream', (stream) => {
// Set altsvc for a specific stream
stream.session.altsvc('h2=":8000"', stream.id);
});
```

Sending an `ALTSVC` frame with a specific stream ID indicates that the alternate
service is associated with the origin of the given `Http2Stream`.

The `alt` and origin string *must* contain only ASCII bytes and are
strictly interpreted as a sequence of ASCII bytes. The special value `'clear'`
may be passed to clear any previously set alternative service for a given
domain.

When a string is passed for the `originOrStream` argument, it will be parsed as
a URL and the origin will be derived. For insetance, the origin for the
HTTP URL `'https://example.org/foo/bar'` is the ASCII string
`'https://example.org'`. An error will be thrown if either the given string
cannot be parsed as a URL or if a valid origin cannot be derived.

A `URL` object, or any object with an `origin` property, may be passed as
`originOrStream`, in which case the value of the `origin` property will be
used. The value of the `origin` property *must* be a properly serialized
ASCII origin.

#### Specifying alternative services

The format of the `alt` parameter is strictly defined by [RFC 7838][] as an
ASCII string containing a comma-delimited list of "alternative" protocols
associated with a specific host and port.

For example, the value `'h2="example.org:81"'` indicates that the HTTP/2
protocol is available on the host `'example.org'` on TCP/IP port 81. The
host and port *must* be contained within the quote (`"`) characters.

Multiple alternatives may be specified, for instance: `'h2="example.org:81",
h2=":82"'`

The protocol identifier (`'h2'` in the examples) may be any valid
[ALPN Protocol ID][].

The syntax of these values is not validated by the Node.js implementation and
are passed through as provided by the user or received from the peer.

### Class: ClientHttp2Session
<!-- YAML
added: v8.4.0
-->

#### Event: 'altsvc'
<!-- YAML
added: REPLACEME
-->

The `'altsvc'` event is emitted whenever an `ALTSVC` frame is received by
the client. The event is emitted with the `ALTSVC` value, origin, and stream
ID, if any. If no `origin` is provided in the `ALTSVC` frame, `origin` will
be an empty string.

```js
const http2 = require('http2');
const client = http2.connect('https://example.org');

client.on('altsvc', (alt, origin, stream) => {
console.log(alt);
console.log(origin);
console.log(stream);
});
```

#### clienthttp2session.request(headers[, options])
<!-- YAML
added: v8.4.0
Expand Down Expand Up @@ -2850,6 +2942,7 @@ following additional properties:


[ALPN negotiation]: #http2_alpn_negotiation
[ALPN Protocol ID]: https://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xhtml#alpn-protocol-ids
[Compatibility API]: #http2_compatibility_api
[HTTP/1]: http.html
[HTTP/2]: https://tools.ietf.org/html/rfc7540
Expand All @@ -2858,6 +2951,7 @@ following additional properties:
[Http2Session and Sockets]: #http2_http2session_and_sockets
[Performance Observer]: perf_hooks.html
[Readable Stream]: stream.html#stream_class_stream_readable
[RFC 7838]: https://tools.ietf.org/html/rfc7838
[Settings Object]: #http2_settings_object
[Using options.selectPadding]: #http2_using_options_selectpadding
[Writable Stream]: stream.html#stream_writable_streams
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4 changes: 4 additions & 0 deletions lib/internal/errors.js
Original file line number Diff line number Diff line change
Expand Up @@ -184,6 +184,10 @@ E('ERR_ENCODING_NOT_SUPPORTED', 'The "%s" encoding is not supported');
E('ERR_FALSY_VALUE_REJECTION', 'Promise was rejected with falsy value');
E('ERR_HTTP2_ALREADY_SHUTDOWN',
'Http2Session is already shutdown or destroyed');
E('ERR_HTTP2_ALTSVC_INVALID_ORIGIN',
'HTTP/2 ALTSVC frames require a valid origin');
E('ERR_HTTP2_ALTSVC_LENGTH',
'HTTP/2 ALTSVC frames are limited to 16382 bytes');
E('ERR_HTTP2_CONNECT_AUTHORITY',
':authority header is required for CONNECT requests');
E('ERR_HTTP2_CONNECT_PATH',
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62 changes: 62 additions & 0 deletions lib/internal/http2/core.js
Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,9 @@ const kMaxFrameSize = (2 ** 24) - 1;
const kMaxInt = (2 ** 32) - 1;
const kMaxStreams = (2 ** 31) - 1;

// eslint-disable-next-line no-control-regex
const kQuotedString = /^[\x09\x20-\x5b\x5d-\x7e\x80-\xff]*$/;

const {
assertIsObject,
assertValidPseudoHeaderResponse,
Expand Down Expand Up @@ -362,6 +365,16 @@ function onFrameError(id, type, code) {
process.nextTick(emit, emitter, 'frameError', type, code, id);
}

function onAltSvc(stream, origin, alt) {
const session = this[kOwner];
if (session.destroyed)
return;
debug(`Http2Session ${sessionName(session[kType])}: altsvc received: ` +
`stream: ${stream}, origin: ${origin}, alt: ${alt}`);
session[kUpdateTimer]();
process.nextTick(emit, session, 'altsvc', alt, origin, stream);
}

// Receiving a GOAWAY frame from the connected peer is a signal that no
// new streams should be created. If the code === NGHTTP2_NO_ERROR, we
// are going to send our close, but allow existing frames to close
Expand Down Expand Up @@ -704,6 +717,7 @@ function setupHandle(socket, type, options) {
handle.onheaders = onSessionHeaders;
handle.onframeerror = onFrameError;
handle.ongoawaydata = onGoawayData;
handle.onaltsvc = onAltSvc;

if (typeof options.selectPadding === 'function')
handle.ongetpadding = onSelectPadding(options.selectPadding);
Expand Down Expand Up @@ -1150,6 +1164,54 @@ class ServerHttp2Session extends Http2Session {
get server() {
return this[kServer];
}

// Submits an altsvc frame to be sent to the client. `stream` is a
// numeric Stream ID. origin is a URL string that will be used to get
// the origin. alt is a string containing the altsvc details. No fancy
// API is provided for that.
altsvc(alt, originOrStream) {
if (this.destroyed)
throw new errors.Error('ERR_HTTP2_INVALID_SESSION');

let stream = 0;
let origin;

if (typeof originOrStream === 'string') {
origin = (new URL(originOrStream)).origin;
if (origin === 'null')
throw new errors.TypeError('ERR_HTTP2_ALTSVC_INVALID_ORIGIN');
} else if (typeof originOrStream === 'number') {
if (originOrStream >>> 0 !== originOrStream || originOrStream === 0)
throw new errors.RangeError('ERR_OUT_OF_RANGE', 'originOrStream');
stream = originOrStream;
} else if (originOrStream !== undefined) {
// Allow origin to be passed a URL or object with origin property
if (originOrStream !== null && typeof originOrStream === 'object')
origin = originOrStream.origin;
// Note: if originOrStream is an object with an origin property other
// than a URL, then it is possible that origin will be malformed.
// We do not verify that here. Users who go that route need to
// ensure they are doing the right thing or the payload data will
// be invalid.
if (typeof origin !== 'string') {
throw new errors.TypeError('ERR_INVALID_ARG_TYPE', 'originOrStream',
['string', 'number', 'URL', 'object']);
} else if (origin === 'null' || origin.length === 0) {
throw new errors.TypeError('ERR_HTTP2_ALTSVC_INVALID_ORIGIN');
}
}

if (typeof alt !== 'string')
throw new errors.TypeError('ERR_INVALID_ARG_TYPE', 'alt', 'string');
if (!kQuotedString.test(alt))
throw new errors.TypeError('ERR_INVALID_CHAR', 'alt');

// Max length permitted for ALTSVC
if ((alt.length + (origin !== undefined ? origin.length : 0)) > 16382)
throw new errors.TypeError('ERR_HTTP2_ALTSVC_LENGTH');

this[kHandle].altsvc(stream, origin || '', alt);
}
}

// ClientHttp2Session instances have to wait for the socket to connect after
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1 change: 1 addition & 0 deletions src/env.h
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Expand Up @@ -180,6 +180,7 @@ class ModuleWrap;
V(netmask_string, "netmask") \
V(nsname_string, "nsname") \
V(ocsp_request_string, "OCSPRequest") \
V(onaltsvc_string, "onaltsvc") \
V(onchange_string, "onchange") \
V(onclienthello_string, "onclienthello") \
V(oncomplete_string, "oncomplete") \
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76 changes: 76 additions & 0 deletions src/node_http2.cc
Original file line number Diff line number Diff line change
Expand Up @@ -103,6 +103,11 @@ Http2Options::Http2Options(Environment* env) {
// are required to buffer.
nghttp2_option_set_no_auto_window_update(options_, 1);

// Enable built in support for ALTSVC frames. Once we add support for
// other non-built in extension frames, this will need to be handled
// a bit differently. For now, let's let nghttp2 take care of it.
nghttp2_option_set_builtin_recv_extension_type(options_, NGHTTP2_ALTSVC);

AliasedBuffer<uint32_t, v8::Uint32Array>& buffer =
env->http2_state()->options_buffer;
uint32_t flags = buffer[IDX_OPTIONS_FLAGS];
Expand Down Expand Up @@ -847,6 +852,10 @@ inline int Http2Session::OnFrameReceive(nghttp2_session* handle,
break;
case NGHTTP2_PING:
session->HandlePingFrame(frame);
break;
case NGHTTP2_ALTSVC:
session->HandleAltSvcFrame(frame);
break;
default:
break;
}
Expand Down Expand Up @@ -1185,6 +1194,34 @@ inline void Http2Session::HandleGoawayFrame(const nghttp2_frame* frame) {
MakeCallback(env()->ongoawaydata_string(), arraysize(argv), argv);
}

// Called by OnFrameReceived when a complete ALTSVC frame has been received.
inline void Http2Session::HandleAltSvcFrame(const nghttp2_frame* frame) {
Isolate* isolate = env()->isolate();
HandleScope scope(isolate);
Local<Context> context = env()->context();
Context::Scope context_scope(context);

int32_t id = GetFrameID(frame);

nghttp2_extension ext = frame->ext;
nghttp2_ext_altsvc* altsvc = static_cast<nghttp2_ext_altsvc*>(ext.payload);
DEBUG_HTTP2SESSION(this, "handling altsvc frame");

Local<Value> argv[3] = {
Integer::New(isolate, id),
String::NewFromOneByte(isolate,
altsvc->origin,
v8::NewStringType::kNormal,
altsvc->origin_len).ToLocalChecked(),
String::NewFromOneByte(isolate,
altsvc->field_value,
v8::NewStringType::kNormal,
altsvc->field_value_len).ToLocalChecked(),
};

MakeCallback(env()->onaltsvc_string(), arraysize(argv), argv);
}

// Called by OnFrameReceived when a complete PING frame has been received.
inline void Http2Session::HandlePingFrame(const nghttp2_frame* frame) {
bool ack = frame->hd.flags & NGHTTP2_FLAG_ACK;
Expand Down Expand Up @@ -2494,6 +2531,44 @@ void Http2Stream::RefreshState(const FunctionCallbackInfo<Value>& args) {
}
}

void Http2Session::AltSvc(int32_t id,
uint8_t* origin,
size_t origin_len,
uint8_t* value,
size_t value_len) {
Http2Scope h2scope(this);
CHECK_EQ(nghttp2_submit_altsvc(session_, NGHTTP2_FLAG_NONE, id,
origin, origin_len, value, value_len), 0);
}

// Submits an AltSvc frame to the sent to the connected peer.
void Http2Session::AltSvc(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
Http2Session* session;
ASSIGN_OR_RETURN_UNWRAP(&session, args.Holder());

int32_t id = args[0]->Int32Value(env->context()).ToChecked();

// origin and value are both required to be ASCII, handle them as such.
Local<String> origin_str = args[1]->ToString(env->context()).ToLocalChecked();
Local<String> value_str = args[2]->ToString(env->context()).ToLocalChecked();

size_t origin_len = origin_str->Length();
size_t value_len = value_str->Length();

CHECK_LE(origin_len + value_len, 16382); // Max permitted for ALTSVC
// Verify that origin len != 0 if stream id == 0, or
// that origin len == 0 if stream id != 0
CHECK((origin_len != 0 && id == 0) || (origin_len == 0 && id != 0));

MaybeStackBuffer<uint8_t> origin(origin_len);
MaybeStackBuffer<uint8_t> value(value_len);
origin_str->WriteOneByte(*origin);
value_str->WriteOneByte(*value);

session->AltSvc(id, *origin, origin_len, *value, value_len);
}

// Submits a PING frame to be sent to the connected peer.
void Http2Session::Ping(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
Expand Down Expand Up @@ -2711,6 +2786,7 @@ void Initialize(Local<Object> target,
session->SetClassName(http2SessionClassName);
session->InstanceTemplate()->SetInternalFieldCount(1);
AsyncWrap::AddWrapMethods(env, session);
env->SetProtoMethod(session, "altsvc", Http2Session::AltSvc);
env->SetProtoMethod(session, "ping", Http2Session::Ping);
env->SetProtoMethod(session, "consume", Http2Session::Consume);
env->SetProtoMethod(session, "destroy", Http2Session::Destroy);
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7 changes: 7 additions & 0 deletions src/node_http2.h
Original file line number Diff line number Diff line change
Expand Up @@ -800,6 +800,11 @@ class Http2Session : public AsyncWrap {
void Consume(Local<External> external);
void Unconsume();
void Goaway(uint32_t code, int32_t lastStreamID, uint8_t* data, size_t len);
void AltSvc(int32_t id,
uint8_t* origin,
size_t origin_len,
uint8_t* value,
size_t value_len);

bool Ping(v8::Local<v8::Function> function);

Expand Down Expand Up @@ -879,6 +884,7 @@ class Http2Session : public AsyncWrap {
static void UpdateChunksSent(const FunctionCallbackInfo<Value>& args);
static void RefreshState(const FunctionCallbackInfo<Value>& args);
static void Ping(const FunctionCallbackInfo<Value>& args);
static void AltSvc(const FunctionCallbackInfo<Value>& args);

template <get_setting fn>
static void RefreshSettings(const FunctionCallbackInfo<Value>& args);
Expand Down Expand Up @@ -923,6 +929,7 @@ class Http2Session : public AsyncWrap {
inline void HandlePriorityFrame(const nghttp2_frame* frame);
inline void HandleSettingsFrame(const nghttp2_frame* frame);
inline void HandlePingFrame(const nghttp2_frame* frame);
inline void HandleAltSvcFrame(const nghttp2_frame* frame);

// nghttp2 callbacks
static inline int OnBeginHeadersCallback(
Expand Down
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