SOCKS5 Proxy Support

.. _socks5_interface:

SOCKS5 Proxy Support ####################

.. contents:: :local: :depth: 2

Overview

The SOCKS library implements SOCKS5 support, which allows Zephyr to connect to peer devices via a network proxy.

See this SOCKS5 Wikipedia article <https://en.wikipedia.org/wiki/SOCKS#SOCKS5>_ for a detailed overview of how SOCKS5 works.

For more information about the protocol itself, see :rfc:1928.

SOCKS5 API

The SOCKS5 support is enabled by :kconfig:option:CONFIG_SOCKS Kconfig variable. Application wanting to use the SOCKS5 must set the SOCKS5 proxy host address by calling :c:func:setsockopt() like this:

.. code-block:: c

static int set_proxy(int sock, const struct sockaddr *proxy_addr,
                     socklen_t proxy_addrlen)
{
    int ret;

    ret = setsockopt(sock, SOL_SOCKET, SO_SOCKS5,
                     proxy_addr, proxy_addrlen);
    if (ret < 0) {
            return -errno;
    }

    return 0;
}

SOCKS5 Proxy Usage in MQTT

For MQTT client, there is :c:func:mqtt_client_set_proxy() API that the application can call to setup SOCKS5 proxy. See :zephyr:code-sample:mqtt-publisher sample application for usage example.