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openziti/ziti-tunnel-sdk-c

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Ziti Tunneler SDK

The Ziti Tunneler SDK provides protocol translation and other common functions that are useful to Ziti Tunnelers.

What's a Ziti Tunneler?

The main article about tunnelers is here. Editors may follow the "Edit this page" link on every page.

What is the Ziti Tunneler SDK?

The Ziti Tunneler SDK provides functionality that is common to Ziti Tunnelers across supported operating systems:

  • Converse with TCP/IP peers
  • Map TCP/IP connections to Ziti sessions
  • Respond to DNS queries for Ziti service hostnames

A Ziti Tunneler application that uses the Ziti Tunneler SDK only needs to implement platform-specific functionality, such as creating a virtual network interface, and providing a user interface.

A set of callback functions that interact with the specific ziti-sdk that the application uses (e.g. ziti-sdk-c, ziti-sdk-go).

The Ziti Tunneler SDK includes an implementation of the required callback functions for ziti-sdk-c. Here's how a minimal tunneler application written in C could use the Ziti Tunneler SDK:

int main(int argc, char *argv[]) {
    uv_loop_t *nf_loop = uv_default_loop();
    netif_driver tun = tun_open(NULL, 0); /* open a tun device, and */

    if (tun == NULL) {
        fprintf(stderr, "failed to open network interface: %s\n", tun_error);
        return 1;
    }

    tunneler_sdk_options tunneler_opts = {
            .netif_driver = tun,
            .ziti_dial = ziti_sdk_c_dial,
            .ziti_close = ziti_sdk_c_close,
            .ziti_write = ziti_sdk_c_write
    };
    tunneler_context TUNNEL_CTX = NF_tunneler_init(&tunneler_opts, nf_loop);

    nf_options opts = {
            .init_cb = on_nf_init,
            .config = argv[1],
            .service_cb = on_service,
            .ctx = TUNNEL_CTX, /* this is passed to the service_cb */
            .refresh_interval = 10,
            .config_types = cfg_types,
    };

    if (NF_init_opts(&opts, nf_loop, NULL) != 0) {
        fprintf(stderr, "failed to initialize ziti\n");
        return 1;
    }

    if (uv_run(nf_loop, UV_RUN_DEFAULT) != 0) {
        fprintf(stderr, "failed to run event loop\n");
        exit(1);
    }

    free(TUNNEL_CTX);
    return 0;
}

Once the Ziti Tunneler SDK is initialized with a network device and ziti-sdk callbacks, a tunneler application only needs to indicate which service(s) that should be

Run with Docker

Please refer to the Docker README for instructions to run ziti-edge-tunnel with Docker.

Multi-Platform Linux Crossbuild Container

The purpose of this container is to document the process of building locally the Linux executables in the same way as the GitHub Actions workflow (CI). By default, this produces executables for each supported platform architecture: amd64, arm64. You may instead build for a particular architecture only by specifying the architecture as a parameter to the docker run command as shown below.

Build the Linux Crossbuild Container Image

You only need to build the container image once unless you change the Dockerfile or ./docker/linux-build.sh (the container's entrypoint).

# build a container image named "ziti-edge-tunnel-builder" with the Dockerfile
docker build \
    --tag=ziti-edge-tunnel-builder \
    --file=./docker/Dockerfile.linux-build \
    --build-arg uid=$UID \
    --build-arg gid=$GID .

Run the Linux Crossbuild Container

Executing the following docker run command will:

  1. Mount the top-level of this repo on the container's /mnt
  2. Run /mnt/docker/linux-build.sh ${@} inside the container
  3. Deposit built executables in /mnt/build which is a top-level dir in this repo after running the container
# build for all architectures: amd64 arm64
docker run \
    --rm \
    --name=ziti-edge-tunnel-builder \
    --volume=$PWD:/mnt \
    ziti-edge-tunnel-builder \
        arm arm64 amd64

# build only amd64 with openssl instead of default mbedtls
docker run \
    --rm \
    --name=ziti-edge-tunnel-builder \
    --volume=$PWD:/mnt \
    ziti-edge-tunnel-builder \
        --use-openssl amd64

You will find each artifact in ./build-${ARCH}/programs/ziti-edge-tunnel/ziti-edge-tunnel.