feat(dns): Implement resolving /dnsaddr for wasm target

libp2p/CHANGELOG.md

@@ -1,5 +1,7 @@
 ## 0.57.0
-
+- Make the `dns` feature available on `wasm32` targets, where `libp2p-dns` resolves names over 
+  DNS-over-HTTPS. Previously `libp2p-dns` was a non-`wasm32` dependency only.
+  See [PR XXXX](https://github.com/libp2p/rust-libp2p/pull/XXXX)
 - Remove `wasm-bindgen` feature and make `wasm` support implicit.
   See [PR 6102](https://github.com/libp2p/rust-libp2p/pull/6102)
 - Raise MSRV to 1.88.0.

libp2p/Cargo.toml

@@ -99,6 +99,7 @@ libp2p-autonat = { workspace = true, optional = true }
 libp2p-connection-limits = { workspace = true }
 libp2p-core = { workspace = true }
 libp2p-dcutr = { workspace = true, optional = true }
+libp2p-dns = { workspace = true, optional = true }
 libp2p-floodsub = { workspace = true, optional = true }
 libp2p-gossipsub = { workspace = true, optional = true }
 libp2p-identify = { workspace = true, optional = true }
@@ -124,7 +125,6 @@ libp2p-websocket-websys = { workspace = true, optional = true }
 libp2p-webtransport-websys = { workspace = true, optional = true }
 
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
-libp2p-dns = { workspace = true, optional = true }
 libp2p-mdns = { workspace = true, optional = true }
 libp2p-memory-connection-limits = { workspace = true, optional = true }
 libp2p-quic = { workspace = true, optional = true }

libp2p/src/lib.rs

@@ -50,7 +50,6 @@ pub use libp2p_core::multihash;
 pub use libp2p_dcutr as dcutr;
 #[cfg(feature = "dns")]
 #[cfg_attr(docsrs, doc(cfg(feature = "dns")))]
-#[cfg(not(target_arch = "wasm32"))]
 #[doc(inline)]
 pub use libp2p_dns as dns;
 #[cfg(feature = "floodsub")]

transports/dns/CHANGELOG.md

@@ -1,5 +1,13 @@
 ## 0.45.0
 
+- Support DNS transport for wasm32 targets that resolves DNS components over DNS-over-HTTPS (DoH).
+  `/dnsaddr` is always resolved, however `/dns`, `/dns4` and `/dns6` are governed by the
+  `DnsResolution` policy (default to `DnsResolutionAuto`) where addresses containing a explicit protocols
+  (i.e. `webrtc-direct`) are resolved to `/ip4`/`/ip6`, while the rest are passed through to the inner
+  transport unchanged, since browsers resolve those hostnames natively and need
+  the hostname preserved for SNI.
+  See [PR XXXX](https://github.com/libp2p/rust-libp2p/pull/XXXX).
+
 - Update `hickory` dependencies to `v0.26`.
   See [PR 6423](https://github.com/libp2p/rust-libp2p/pull/6423)
   `ResolveError` now aliases hickory's `NetError`,

transports/dns/Cargo.toml

@@ -13,13 +13,29 @@ categories = ["network-programming", "asynchronous"]
 [dependencies]
 futures = { workspace = true }
 libp2p-core = { workspace = true }
-libp2p-identity = { workspace = true }
 parking_lot = "0.12.5"
-hickory-resolver = { workspace = true, features = ["system-config"] }
 smallvec = "1.15.1"
 tracing = { workspace = true }
 
-[dev-dependencies]
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
+hickory-resolver = { workspace = true, features = ["system-config"] }
+
+[target.'cfg(target_arch = "wasm32")'.dependencies]
+getrandom = { workspace = true }
+js-sys = "0.3.77"
+send_wrapper = { version = "0.6.0", features = ["futures"] }
+serde = { version = "1.0.228", features = ["derive"] }
+serde_json = "1.0.150"
+thiserror = { workspace = true }
+url = "2.5.4"
+wasm-bindgen = "0.2.100"
+wasm-bindgen-futures = { workspace = true }
+web-sys = { version = "0.3.77", features = ["AbortSignal", "Headers", "Request", "RequestInit", "Response", "Window", "WorkerGlobalScope"] }
+
+[target.'cfg(target_arch = "wasm32")'.dev-dependencies]
+wasm-bindgen-test = "0.3.50"
+
+[target.'cfg(not(target_arch = "wasm32"))'.dev-dependencies]
 libp2p-identity = { workspace = true, features = ["rand"] }
 tokio = { workspace = true, features = ["rt", "time"] }
 tracing-subscriber = { workspace = true, features = ["env-filter"] }
@@ -31,6 +47,7 @@ tokio = ["hickory-resolver/tokio"]
 # More information: https://docs.rs/about/builds#cross-compiling
 [package.metadata.docs.rs]
 all-features = true
+targets = ["x86_64-unknown-linux-gnu", "wasm32-unknown-unknown"]
 
 [lints]
 workspace = true