libp2p · mergify · Nov 17, 2022 · Jun 29, 2022 · Jun 29, 2022 · Jun 30, 2022
diff --git a/Cargo.toml b/Cargo.toml
@@ -47,6 +47,7 @@ full = [
     "wasm-bindgen",
     "wasm-ext",
     "wasm-ext-websocket",
+    "webrtc",
     "websocket",
     "yamux",
 ]
@@ -85,7 +86,8 @@ secp256k1 = ["libp2p-core/secp256k1"]
 rsa = ["libp2p-core/rsa"]
 ecdsa = ["libp2p-core/ecdsa"]
 serde = ["libp2p-core/serde", "libp2p-kad?/serde", "libp2p-gossipsub?/serde"]
-tokio = ["libp2p-mdns?/tokio", "libp2p-tcp?/tokio", "libp2p-dns?/tokio"]
+webrtc = ["dep:libp2p-webrtc"]
+tokio = ["libp2p-mdns?/tokio", "libp2p-tcp?/tokio", "libp2p-dns?/tokio", "libp2p-webrtc?/tokio"]
 async-std = ["libp2p-mdns?/async-io", "libp2p-tcp?/async-io", "libp2p-dns?/async-std"]
 
 [package.metadata.docs.rs]
@@ -118,8 +120,9 @@ libp2p-swarm = { version = "0.40.1", path = "swarm" }
 libp2p-swarm-derive = { version = "0.30.1", path = "swarm-derive" }
 libp2p-uds = { version = "0.36.0", path = "transports/uds", optional = true }
 libp2p-wasm-ext = { version = "0.37.0", path = "transports/wasm-ext", optional = true }
+libp2p-webrtc = { version = "0.1.0", path = "transports/webrtc", optional = true }
 libp2p-yamux = { version = "0.41.0", path = "muxers/yamux", optional = true }
-multiaddr = { version = "0.14.0" }
+multiaddr = { version = "0.15.0" }
 parking_lot = "0.12.0"
 pin-project = "1.0.0"
 smallvec = "1.6.1"
@@ -134,6 +137,10 @@ libp2p-websocket = { version = "0.39.0", path = "transports/websocket", optional
 [target.'cfg(not(target_os = "unknown"))'.dependencies]
 libp2p-gossipsub = { version = "0.42.1", path = "protocols/gossipsub", optional = true }
 
+[patch.crates-io]
+# TODO: remove once a new version of rust-multiaddr is released
+multiaddr = { version = "0.15.0", git = "https://github.com/multiformats/rust-multiaddr.git", branch = "master" }
+
 [dev-dependencies]
 async-std = { version = "1.6.2", features = ["attributes"] }
 async-trait = "0.1"
@@ -173,7 +180,8 @@ members = [
     "transports/tcp",
     "transports/uds",
     "transports/websocket",
-    "transports/wasm-ext"
+    "transports/wasm-ext",
+    "transports/webrtc"
 ]
 
 [[example]]

diff --git a/core/Cargo.toml b/core/Cargo.toml
@@ -22,7 +22,7 @@ instant = "0.1.11"
 lazy_static = "1.2"
 libsecp256k1 = { version = "0.7.0", optional = true }
 log = "0.4"
-multiaddr = { version = "0.14.0" }
+multiaddr = { version = "0.15.0" }
 multihash = { version = "0.16", default-features = false, features = ["std", "multihash-impl", "identity", "sha2"] }
 multistream-select = { version = "0.12", path = "../misc/multistream-select" }
 p256 = { version = "0.11.1", default-features = false, features = ["ecdsa"], optional = true }

diff --git a/misc/prost-codec/src/lib.rs b/misc/prost-codec/src/lib.rs
@@ -79,3 +79,12 @@ pub enum Error {
         std::io::Error,
     ),
 }
+
+impl From<Error> for std::io::Error {
+    fn from(e: Error) -> Self {
+        match e {
+            Error::Decode(e) => e.into(),
+            Error::Io(e) => e,
+        }
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
@@ -189,6 +189,10 @@ pub use libp2p_uds as uds;
 #[cfg_attr(docsrs, doc(cfg(feature = "wasm-ext")))]
 #[doc(inline)]
 pub use libp2p_wasm_ext as wasm_ext;
+#[cfg(feature = "webrtc")]
+#[cfg_attr(docsrs, doc(cfg(feature = "webrtc")))]
+#[doc(inline)]
+pub use libp2p_webrtc as webrtc;
 #[cfg(feature = "websocket")]
 #[cfg_attr(docsrs, doc(cfg(feature = "websocket")))]
 #[cfg(not(any(target_os = "emscripten", target_os = "wasi", target_os = "unknown")))]

diff --git a/transports/webrtc/Cargo.toml b/transports/webrtc/Cargo.toml
@@ -0,0 +1,54 @@
+[package]
+name = "libp2p-webrtc"
+version = "0.1.0"
+authors = ["Parity Technologies <[email protected]>"]
+description = "WebRTC transport for libp2p"
+repository = "https://github.com/libp2p/rust-libp2p"
+license = "MIT"
+edition = "2021"
+keywords = ["peer-to-peer", "libp2p", "networking"]
+categories = ["network-programming", "asynchronous"]
+
+[dependencies]
+asynchronous-codec = "0.6"
+async-trait = "0.1"
+bytes = "1"
+fnv = "1.0"
+futures = "0.3"
+futures-lite = "1"
+futures-timer = "3"
+hex = "0.4"
+if-watch = "2.0"
+libp2p-core = { version = "0.37.0", path = "../../core"  }
+libp2p-noise = { version = "0.40.0", path = "../../transports/noise" }
+log = "0.4"
+multihash = { version = "0.16", default-features = false, features = ["sha2"] }
+multibase = "0.9"
+prost = "0.11"
+prost-codec = { version = "0.2", path = "../../misc/prost-codec" }
+rand = "0.8"
+rcgen = "0.9.3"
+serde = { version = "1.0", features = ["derive"] }
+stun = "0.4"
+thiserror = "1"
+tinytemplate = "1.2"
+
+tokio = { version = "1.18", features = ["net"], optional = true}
+tokio-util = { version = "0.7", features = ["compat"], optional = true }
+webrtc = { version = "0.5.0", optional = true }
+
+[features]
+tokio = ["dep:tokio", "dep:tokio-util", "dep:webrtc"]
+
+[build-dependencies]
+prost-build = "0.11"
+
+[dev-dependencies]
+anyhow = "1.0"
+env_logger = "0.9"
+hex-literal = "0.3"
+libp2p = { path = "../..", features = ["request-response", "webrtc"], default-features = false }
+multihash = { version = "0.16", default-features = false, features = ["sha3"] }
+quickcheck = "1"
+rand_core = "0.5"
+unsigned-varint = { version = "0.7", features = ["asynchronous_codec"] }
diff --git a/transports/webrtc/build.rs b/transports/webrtc/build.rs
@@ -0,0 +1,23 @@
+// Copyright 2022 Protocol Labs.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+fn main() {
+    prost_build::compile_protos(&["src/message.proto"], &["src"]).unwrap();
+}
diff --git a/transports/webrtc/src/lib.rs b/transports/webrtc/src/lib.rs
@@ -0,0 +1,90 @@
+// Copyright 2022 Parity Technologies (UK) Ltd.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+//! Implementation of the [`libp2p_core::Transport`] trait for WebRTC protocol without a signaling
+//! server.
+//!
+//! # Overview
+//!
+//! ## ICE
+//!
+//! RFCs: 8839, 8445 See also:
+//! <https://tools.ietf.org/id/draft-ietf-rtcweb-sdp-08.html#rfc.section.5.2.3>
+//!
+//! The WebRTC protocol uses ICE in order to establish a connection.
+//!
+//! In a typical ICE setup, there are two endpoints, called agents, that want to communicate. One
+//! of these two agents can be the local browser, while the other agent is the target of the
+//! connection.
+//!
+//! Even though in this specific context all we want is a simple client-server communication, it is
+//! helpful to keep in mind that ICE was designed to solve the problem of NAT traversal.
+//!
+//! The ICE workflow works as follows:
+//!
+//! - An "offerer" determines ways in which it could be accessible (either an
+//!   IP address or through a relay using a TURN server), which are called "candidates". It then
+//!   generates a small text payload in a format called SDP, that describes the request for a
+//!   connection.
+//! - The offerer sends this SDP-encoded message to the answerer. The medium through which this
+//!   exchange is done is out of scope of the ICE protocol.
+//! - The answerer then finds its own candidates, and generates an answer, again in the SDP format.
+//!   This answer is sent back to the offerer.
+//! - Each agent then tries to connect to the remote's candidates.
+//!
+//! We pretend to send the offer to the remote agent (the target of the connection), then pretend
+//! that it has found a valid IP address for itself (i.e. a candidate), then pretend that the SDP
+//! answer containing this candidate has been sent back. This will cause the offerer to execute
+//! step 4: try to connect to the remote's candidate.
+//!
+//! ## TCP or UDP
+//!
+//! WebRTC by itself doesn't hardcode any specific protocol for media streams. Instead, it is the
+//! SDP message of the offerer that specifies which protocol to use. In our use case (one or more
+//! data channels), we know that the offerer will always request either TCP+DTLS+SCTP, or
+//! UDP+DTLS+SCTP.
+//!
+//! The implementation only supports UDP at the moment, so if the offerer requests TCP+DTLS+SCTP, it
+//! will not respond. Support for TCP may be added in the future (see
+//! <https://github.com/webrtc-rs/webrtc/issues/132>).
+//!
+//! ## DTLS+SCTP
+//!
+//! RFCs: 8841, 8832
+//!
+//! In both cases (TCP or UDP), the next layer is DTLS. DTLS is similar to the well-known TLS
+//! protocol, except that it doesn't guarantee ordering of delivery (as this is instead provided by
+//! the SCTP layer on top of DTLS). In other words, once the TCP or UDP connection is established,
+//! the browser will try to perform a DTLS handshake.
+//!
+//! During the ICE negotiation, each agent must include in its SDP packet a hash of the self-signed
+//! certificate that it will use during the DTLS handshake. In our use-case, where we try to
+//! hand-crate the SDP answer generated by the remote, this is problematic. A way to solve this
+//! is to make the hash a part of the remote's multiaddr. On the server side, we turn
+//! certificate verification off.
+
+mod message_proto {
+    #![allow(clippy::derive_partial_eq_without_eq)]
+
+    include!(concat!(env!("OUT_DIR"), "/webrtc.pb.rs"));
+}
+
+#[cfg(feature = "tokio")]
+pub mod tokio;
diff --git a/transports/webrtc/src/message.proto b/transports/webrtc/src/message.proto
@@ -0,0 +1,20 @@
+syntax = "proto2";
+
+package webrtc.pb;
+
+message Message {
+  enum Flag {
+    // The sender will no longer send messages on the stream.
+    FIN = 0;
+    // The sender will no longer read messages on the stream. Incoming data is
+    // being discarded on receipt.
+    STOP_SENDING = 1;
+    // The sender abruptly terminates the sending part of the stream. The
+    // receiver can discard any data that it already received on that stream.
+    RESET = 2;
+  }
+
+  optional Flag flag=1;
+
+  optional bytes message = 2;
+}