cronet-libs

Prebuilt cronet static / shared libraries from naiveproxy (Chromium's network stack: HTTP/2, HTTP/3 QUIC, ECH, …).

This repository contains only the C library build pipeline — there are no Go bindings here. It produces:

• libcronet.a — static library (Linux glibc/musl, macOS, iOS, tvOS, Android)
• libcronet.so — shared library (Linux glibc)
• libcronet.dll— shared library (Windows)

together with the C headers (include/) and the system link flags required to link the static library (lib/<target>/link_flags.txt).

Supported Platforms

Target	OS	CPU
android/386	android	x86
android/amd64	android	x64
android/arm	android	arm
android/arm64	android	arm64
darwin/amd64	mac	x64
darwin/arm64	mac	arm64
ios/arm64	ios	arm64
ios/amd64	ios	amd64
linux/386	linux	x86
linux/amd64	linux	x64
linux/arm	linux	arm
linux/arm64	linux	arm64
linux/loong64	linux	loong64
windows/amd64	win	x64
windows/arm64	win	arm64

How it works

The build is orchestrated by just, whose recipes run the single-file cargo script scripts/build-cronet.rs (get-clang.sh → gn gen → ninja). The script depends only on the Rust standard library, so it compiles with no network access.

Requirements: just, a Rust toolchain with cargo -Zscript support (nightly), and the usual Chromium build deps (gn/ninja, a C/C++ toolchain). No Go.

just recipes:

Recipe	Purpose
just build [target] [libc]	compile + package in one go
just compile [target] [libc]	gn gen + ninja → produce libcronet.{a,so,dll}
just package [target] [libc]	Copy libs to lib/ and headers to include/, dump link flags
just apple	Build every Apple platform
just download-toolchain …	Download clang + sysroot without building
just env [target] [libc]	Print CC/CXX/CGO_LDFLAGS for cross-compiling consumers

The script can also be invoked directly without just: cargo +nightly -Zscript scripts/build-cronet.rs -- build --target linux/amd64.

Build instructions

# --shallow-submodules keeps the naiveproxy submodule a depth-1 clone
# (otherwise it pulls ~124 MB of history).
git clone --recursive --shallow-submodules --depth=1 <this-repo>
cd cronet-libs

just                       # list recipes
just build                 # host target (compile + package)
just build linux/arm64     # cross-compile
just build linux/amd64 musl # static musl Linux build
just apple                 # all Apple platforms

Outputs land in:

lib/<os>_<arch>/libcronet.a        # static lib
lib/<os>_<arch>/libcronet.so       # Linux glibc shared lib
lib/<os>_<arch>/libcronet.dll      # Windows shared lib
lib/<os>_<arch>/link_flags.txt     # system libs/frameworks needed to link .a
include/*.h                        # C headers

The raw ninja output also remains under naiveproxy/src/out/cronet-<os>-<cpu>/ if you prefer to grab it directly.

Cross-compiling

just download-toolchain linux/arm64
just build linux/arm64

# musl (static):
just build linux/amd64 musl

Directories worth caching (CI)

- naiveproxy/src/third_party/llvm-build/
- naiveproxy/src/gn/out/
- naiveproxy/src/chrome/build/pgo_profiles/
- naiveproxy/src/out/sysroot-build/

Linking against the static library

libcronet.a needs a number of system libraries; the exact set is written to lib/<target>/link_flags.txt at package time. Example (Linux):

cc myapp.c -Iinclude lib/linux_amd64/libcronet.a $(cat lib/linux_amd64/link_flags.txt | grep -v '^#')

On Windows / for dynamic linking, ship libcronet.dll / libcronet.so next to your executable.