Add support for "multi-stream connections" #2352

tomaka · 2022-06-07T14:39:09Z

Smoldot contains bindings with the JS code. Some functions in these bindings ask the JS code to open a connection to a multiaddress. On success, the JS code reports that the connection has been opened, and smoldot and the JS communicate in order to send and receive data on that connection.

Internally, smoldot performs a protocol negotiation of Noise + Yamux on these connections, and then applies the encryption and multiplexing internally.

The connect function that the JS must implement accepts as parameter a string multiaddress that the JS decodes in order to know the "actual" type of connection to open. At the moment, this is either a plain TCP/IP connection or a WebSocket connection.

We want to add support for WebRTC. The problem with WebRTC is that it is the browser that performs the encryption and multiplexing, and thus it doesn't fit the model of one stream subdivided internally by smoldot.
For this reason, we have to add in smoldot a second type of connection named "multi-stream connections".
In order to not introduce any ambiguity, the current connections have been renamed to "single-stream connections".

This PR adds support for that other type of connection as a new module in src/libp2p/connection/established.
In collection.rs, peers.rs, and service.rs (which are collections of connections), multi-stream connections are handled the same way as single-stream connections except that the function to add a new connection is different.
Inserting a connection previously returned a ConnectionTask that allows reading/writing on that connection. The ConnectionTask struct has been renamed to SingleStreamConnectionTask and there is now a MultiStreamConnectionTask that has a different API.

I have correspondingly updated the Platform trait of the light-base crate and bin/light-base/network_service so that this type of connection is accessible to the Wasm node. I have also updated the JS <-> Wasm bindings, and the JS code can add support for WebRTC right now after this PR. However I've left bin/wasm-node/rust/platform (i.e. the code that "connects" the low-level bindings that pass u32s around and the higher-level objects) full of todo!s because I would like to refactor this module entirely.

As always, this code hasn't been tested and to be honest it would be a bit miraculous if everything worked first try. I'm opening this PR now because I've been working on it for 2 weeks now, and I would like to land it and iterate on top of it. I believe that my API design is good, and only the implementation details are lacking.

Can be reviewed commit by commit.

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github-actions · 2022-06-07T14:46:51Z

twiggy diff report

Difference in .wasm size before and after this pull request.

 Delta Bytes │ Item
─────────────┼─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
       +7608 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h91ea29f274dd257c
       -7569 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::hd577c4ce39ea0c0e
       -4439 ┊ smoldot::libp2p::collection::ConnectionTask<TNow>::read_write::h5a98749c1f8976ce
       +4097 ┊ smoldot::libp2p::collection::SingleStreamConnectionTask<TNow>::read_write::h4941fc3b8b423bbf
       -2915 ┊ smoldot::libp2p::connection::established::Established<TNow,TRqUd,TNotifUd>::read_write::h19d2afca2e3ff2a1
       +2702 ┊ smoldot::libp2p::connection::established::single_stream::SingleStream<TNow,TRqUd,TNotifUd>::read_write::h364933ca5cb6bf4f
       +2645 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h4852f61409e7b92a
       -2575 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::ha7bec94c2115ef9d
       +2560 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h3f3d43ee50519cb0
       -2456 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::ha8c738376ea0a8fd
       +2372 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h4c742e8762a3aaf3
       +1740 ┊ smoldot::libp2p::connection::established::multi_stream::MultiStream<TNow,TSubId,TRqUd,TNotifUd>::substream_read_write::hdf84bbd7e4172582
       -1607 ┊ smoldot::libp2p::connection::established::Established<TNow,TRqUd,TNotifUd>::process_substream::h8f113b791cc040e4
       +1511 ┊ smoldot::libp2p::connection::established::single_stream::SingleStream<TNow,TRqUd,TNotifUd>::process_substream::hd681daf4c6ec674f
       +1384 ┊ smoldot::libp2p::collection::SingleStreamConnectionTask<TNow>::inject_coordinator_message::ha98d19b6eded6cb3
       -1317 ┊ smoldot::libp2p::collection::ConnectionTask<TNow>::inject_coordinator_message::hb2a3bade5b64dc49
       +1309 ┊ smoldot::libp2p::collection::MultiStreamConnectionTask<TNow,TSubId>::inject_coordinator_message::hec6a94df418a3f91
       +1171 ┊ smoldot::libp2p::collection::MultiStreamConnectionTask<TNow,TSubId>::pull_message_to_coordinator::hf62149bdb9fe8fd5
       +1088 ┊ data[0]
        +984 ┊ hashbrown::raw::RawTable<T,A>::reserve_rehash::h9ee0e5796cd5c71f
      +17146 ┊ ... and 502 more.
      +43417 ┊ Σ [522 Total Rows]

melekes

great work @tomaka 💯 did a first pass and everything looks good. will do another one later today or maybe tomorrow

bin/light-base/src/lib.rs

melekes · 2022-06-09T05:49:59Z

bin/light-base/src/network_service.rs

+/// Asynchronous task managing a specific multi-stream connection after it's been open.
+// TODO: a lot of logging disappeared
+async fn multi_stream_connection_task<TPlat: Platform>(
+    mut websocket: TPlat::Connection,


it's no longer a websocket, right? rename to connection or conn or platform_conn whichever makes more sense

bin/light-base/src/network_service.rs

melekes · 2022-06-09T05:50:24Z

bin/light-base/src/network_service.rs

+            }
+
+            if has_message {
+                continue;


there are so many loops in this function. might be good to assign a label to the main one

Suggested change

continue;

continue 'connection_task_loop

bin/wasm-node/javascript/src/worker/bindings.ts

melekes · 2022-06-09T07:15:43Z

src/libp2p/collection.rs

+
+        /// Reverse mapping.
+        // TODO: could be user datas in established?
+        outbound_substreams_mapping2:


Suggested change

outbound_substreams_mapping2:

outbound_substreams_reverse:

src/libp2p/collection.rs

melekes · 2022-06-09T08:35:21Z

src/libp2p/connection/established/multi_stream.rs

+        // TODO: check conflicts between protocol names?
+
+        let num_expected_substreams =
+            config.request_protocols.len() + config.notifications_protocols.len() * 2 + 1;


can u maybe add a comment explaining the logic behind this?

melekes · 2022-06-09T13:02:49Z

src/libp2p/collection.rs

+                    ping_timeout: Duration::from_secs(10),         // TODO: hardcoded
+                    first_out_ping: now + Duration::from_secs(2),  // TODO: hardcoded
+                }),
+                outbound_substreams_mapping: hashbrown::HashMap::with_capacity_and_hasher(


Suggested change

outbound_substreams_mapping: hashbrown::HashMap::with_capacity_and_hasher(

outbound_substreams_map: hashbrown::HashMap::with_capacity_and_hasher(

to be consistent with the rest of the code

src/libp2p/connection/established/multi_stream.rs

melekes

tomaka added 26 commits May 31, 2022 16:48

ConnectionTask -> SingleStreamConnectionTask

c4ac47d

Add draft API to collection.rs

e5627f5

Propagate functions to outer API layers

1e4c2d0

Move established.rs -> single_stream.rs

7b67e86

Restore compilation after previous commit

a8e6c82

Move some types out of single_stream

45cc7f5

Move out reexports from substream module

ea0b4f4

Precise reexports

8bbf3cd

Add draft for multi_stream connection

b0827c1

Move SubstreamId to parent module

a046140

Make multi_stream compile

deb2847

Add TODO in single_stream

2186784

Update Platform trait

9b2acaa

Update network_service

053f0bc

Propagate events in multi_stream

fc948ec

Rename Established -> SingleStream

caa2fbe

Start integration in collection.rs

0b48298

Start proper events handling

f1ea98d

Merge branch 'main' into multistream-ext

a5af782

Now compiles

a0a94a9

Implement ready_substreams()

f2b1130

Add MultiStreamConnectionTask::reset()

6925e65

Fix warnings

e7c85f2

Fix fuzzer

ebf3fa7

Update JS bindings

d38dbbc

Fix warnings

50bfc8b

mergify bot approved these changes Jun 7, 2022

View reviewed changes

Typo and docs

d4b60dd

tomaka mentioned this pull request Jun 7, 2022

wasm-node: Add support for WebRTC #1712

Closed

2 tasks

Rustfmt

a853f84

tomaka requested a review from melekes June 7, 2022 15:00

melekes reviewed Jun 9, 2022

View reviewed changes

melekes reviewed Jun 10, 2022

View reviewed changes

tomaka added 8 commits June 13, 2022 11:12

Renames

2f1abed

Explain num expected substreams

3f0261e

Merge branch 'main' into multistream-ext

4280596

Fix many doclink errors

73d854a

More doclinks fixes

017cf3b

More doclinks

9bf2790

Hopefully last round of doclink fixes

2432d09

I-swear-everything-is-fixed-now

de0c921

melekes approved these changes Jun 14, 2022

View reviewed changes

tomaka mentioned this pull request Jun 14, 2022

Add fake out requests system in peers.rs #2369

Merged

tomaka added 4 commits June 14, 2022 12:03

Hopefully now it's fixed

1f1a04f

Merge branch 'main' into multistream-ext

760d7a5

Merge branch 'main' into multistream-ext

cf49b10

Fix doclinks in wasm-node

05c08ac

tomaka mentioned this pull request Jun 14, 2022

CI: fix spellcheck #2384

Merged

tomaka added the automerge Automatically merge pull request as soon as possible label Jun 14, 2022

Merge branch 'main' into multistream-ext

e812b0f

mergify bot merged commit f1e2a38 into paritytech:main Jun 14, 2022

tomaka deleted the multistream-ext branch June 14, 2022 13:55

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Add support for "multi-stream connections" #2352

Add support for "multi-stream connections" #2352

tomaka commented Jun 7, 2022 •

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	outbound_substreams_mapping: hashbrown::HashMap::with_capacity_and_hasher(
	outbound_substreams_map: hashbrown::HashMap::with_capacity_and_hasher(

Add support for "multi-stream connections" #2352

Add support for "multi-stream connections" #2352

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twiggy diff report

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