Add experimental HTTP/3 via Quiche

Cargo.toml

@@ -43,6 +43,7 @@ default = ["ssl"]
 ssl = ["openssl-sys", "openssl-probe", "curl-sys/ssl"] # OpenSSL/system TLS backend
 mesalink = ["curl-sys/mesalink"] # MesaLink TLS backend
 http2 = ["curl-sys/http2"]
+http3-quiche = ["curl-sys/http3-quiche"]
 spnego = ["curl-sys/spnego"]
 rustls = ["curl-sys/rustls"]
 static-curl = ["curl-sys/static-curl"]

README.md

@@ -128,6 +128,7 @@ with various Cargo features:
   Note that Rustls support is experimental within Curl itself and may have significant bugs, so we don't offer any sort of stability guarantee with this feature.
 - `mesalink`: Enable SSL/TLS support via [MesaLink], an alternative TLS backend written in Rust based on [Rustls]. MesaLink is always statically linked. Disabled by default.
 - `http2`: Enable HTTP/2 support via libnghttp2. Disabled by default.
+- `http3-quiche`: Enable experimental HTTP/3 support via [Quiche](https://github.com/cloudflare/quiche). Disabled by default.
 - `static-curl`: Use a bundled libcurl version and statically link to it. Disabled by default.
 - `static-ssl`: Use a bundled OpenSSL version and statically link to it. Only applies on platforms that use OpenSSL. Disabled by default.
 - `spnego`: Enable SPNEGO support. Disabled by default.

curl-sys/Cargo.toml

@@ -30,6 +30,13 @@ optional = true
 default-features = false
 features = ["client_apis", "error_strings", "tls13", "aesgcm", "chachapoly", "x25519", "ecdh", "ecdsa", "verifier"]
 
+[dependencies.quiche]
+git = "https://github.com/sagebind/quiche"
+branch = "include-metadata"
+optional = true
+default-features = false
+features = ["ffi"]
+
 [dependencies.rustls-ffi]
 version = "0.8"
 optional = true
@@ -52,6 +59,8 @@ cc = "1.0"
 default = ["ssl"]
 ssl = ["openssl-sys"]
 http2 = ["libnghttp2-sys"]
+http3-quiche = ["quiche"]
+http3-quiche-boringssl-vendored = ["quiche/boringssl-vendored"]
 rustls = ["rustls-ffi"]
 static-curl = []
 static-ssl = ["openssl-sys/vendored"]

curl-sys/build.rs

@@ -248,6 +248,14 @@ fn main() {
         }
     }
 
+    if cfg!(feature = "http3-quiche") {
+        cfg.define("USE_QUICHE", None)
+            .file("curl/lib/vquic/vquic.c")
+            .file("curl/lib/vquic/quiche.c");
+
+        cfg.include(env::var_os("DEP_QUICHE_INCLUDE").unwrap());
+    }
+
     println!("cargo:rustc-cfg=link_libz");
     if let Some(path) = env::var_os("DEP_Z_INCLUDE") {
         cfg.include(path);

curl-sys/lib.rs

@@ -10,6 +10,8 @@ extern crate libz_sys;
 extern crate mesalink;
 #[cfg(link_openssl)]
 extern crate openssl_sys;
+#[cfg(feature = "http3-quiche")]
+extern crate quiche;
 #[cfg(feature = "rustls")]
 extern crate rustls_ffi;
 

examples/http3.rs

@@ -0,0 +1,20 @@
+//! Simple HTTP/3 GET
+//!
+//! This example is a Rust adaptation of the [C example of the same
+//! name](https://curl.se/libcurl/c/http3.html).
+
+use curl::easy::Easy;
+
+fn main() -> Result<(), curl::Error> {
+    let mut curl = Easy::new();
+
+    // An HTTP/3-capable server.
+    curl.url("https://cloudflare-quic.com")?;
+
+    // Force HTTP/3 to be used.
+    curl.http_version(curl::easy::HttpVersion::V3)?;
+
+    curl.perform()?;
+
+    Ok(())
+}