Introduce socket service API

include/zephyr/linker/common-rom/common-rom-net.ld

@@ -25,3 +25,7 @@
 #if defined(CONFIG_NET_MGMT_EVENT)
 	ITERABLE_SECTION_ROM(net_mgmt_event_static_handler, 4)
 #endif
+
+#if defined(CONFIG_NET_SOCKETS_SERVICE)
+	ITERABLE_SECTION_RAM(net_socket_service_desc, 4)
+#endif

include/zephyr/net/socket_service.h

@@ -0,0 +1,246 @@
+/**
+ * @file
+ * @brief BSD Socket service API
+ *
+ * API can be used to install a k_work that is called
+ * if there is data received to a socket.
+ */
+
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_INCLUDE_NET_SOCKET_SERVICE_H_
+#define ZEPHYR_INCLUDE_NET_SOCKET_SERVICE_H_
+
+/**
+ * @brief BSD socket service API
+ * @defgroup bsd_socket_service BSD socket service API
+ * @ingroup networking
+ * @{
+ */
+
+#include <sys/types.h>
+#include <zephyr/types.h>
+#include <zephyr/net/socket.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * This struct contains information which socket triggered
+ * calls to the callback function.
+ */
+struct net_socket_service_event {
+	/** k_work that is done when there is desired activity in file descriptor. */
+	struct k_work work;
+	/** Callback to be called for desired socket activity */
+	k_work_handler_t callback;
+	/** Socket information that triggered this event. */
+	struct zsock_pollfd event;
+	/** User data */
+	void *user_data;
+	/** Service back pointer */
+	struct net_socket_service_desc *svc;
+};
+
+/**
+ * Main structure holding socket service configuration information.
+ * The k_work item is created so that when there is data coming
+ * to those fds, the k_work callback is then called.
+ * The workqueue can be set NULL in which case system workqueue is used.
+ * The service descriptor should be created at built time, and then used
+ * as a parameter to register the sockets to be monitored.
+ * User should create needed sockets and then setup the poll struct and
+ * then register the sockets to be monitored at runtime.
+ */
+struct net_socket_service_desc {
+#if CONFIG_NET_SOCKETS_LOG_LEVEL >= LOG_LEVEL_DBG
+	/**
+	 * Owner name. This can be used in debugging to see who has
+	 * registered this service.
+	 */
+	const char *owner;
+#endif
+	/** Workqueue where the work is submitted. */
+	struct k_work_q *work_q;
+	/** Pointer to the list of services that we are listening */
+	struct net_socket_service_event *pev;
+	/** Length of the pollable socket array for this service. */
+	int pev_len;
+	/** Where are my pollfd entries in the global list */
+	int *idx;
+};
+
+#define __z_net_socket_svc_get_name(_svc_id) __z_net_socket_service_##_svc_id
+#define __z_net_socket_svc_get_idx(_svc_id) __z_net_socket_service_idx##_svc_id
+#define __z_net_socket_svc_get_owner __FILE__ ":" STRINGIFY(__LINE__)
+
+extern void net_socket_service_callback(struct k_work *work);
+
+#if CONFIG_NET_SOCKETS_LOG_LEVEL >= LOG_LEVEL_DBG
+#define NET_SOCKET_SERVICE_OWNER .owner = __z_net_socket_svc_get_owner,
+#else
+#define NET_SOCKET_SERVICE_OWNER
+#endif
+
+#define NET_SOCKET_SERVICE_CALLBACK_MODE(_flag)				\
+	IF_ENABLED(_flag,						\
+		   (.work = Z_WORK_INITIALIZER(net_socket_service_callback),))
+
+#define __z_net_socket_service_define(_name, _work_q, _cb, _count, _async, ...) \
+	static int __z_net_socket_svc_get_idx(_name);			\
+	static struct net_socket_service_event				\
+			__z_net_socket_svc_get_name(_name)[_count] = {	\
+		[0 ... ((_count) - 1)] = {				\
+			.event.fd = -1, /* Invalid socket */		\
+			NET_SOCKET_SERVICE_CALLBACK_MODE(_async)	\
+			.callback = _cb,				\
+		}							\
+	};								\
+	COND_CODE_0(NUM_VA_ARGS_LESS_1(__VA_ARGS__), (), __VA_ARGS__)	\
+	const STRUCT_SECTION_ITERABLE(net_socket_service_desc, _name) = { \
+		NET_SOCKET_SERVICE_OWNER				\
+		.work_q = (_work_q),                                    \
+		.pev = __z_net_socket_svc_get_name(_name),		\
+		.pev_len = (_count),					\
+		.idx = &__z_net_socket_svc_get_idx(_name),		\
+	}
+
+/**
+ * @brief Statically define a network socket service.
+ *        The user callback is called asynchronously for this service meaning that
+ *        the service API will not wait until the user callback returns before continuing
+ *        with next socket service.
+ *
+ * The socket service can be accessed outside the module where it is defined using:
+ *
+ * @code extern struct net_socket_service_desc <name>; @endcode
+ *
+ * @note This macro cannot be used together with a static keyword.
+ *       If such a use-case is desired, use NET_SOCKET_SERVICE_ASYNC_DEFINE_STATIC
+ *       instead.
+ *
+ * @param name Name of the service.
+ * @param work_q Pointer to workqueue where the work is done. Can be null in which case
+ *        system workqueue is used.
+ * @param cb Callback function that is called for socket activity.
+ * @param count How many pollable sockets is needed for this service.
+ */
+#define NET_SOCKET_SERVICE_ASYNC_DEFINE(name, work_q, cb, count)	\
+	__z_net_socket_service_define(name, work_q, cb, count, 1)
+
+/**
+ * @brief Statically define a network socket service in a private (static) scope.
+ *        The user callback is called asynchronously for this service meaning that
+ *        the service API will not wait until the user callback returns before continuing
+ *        with next socket service.
+ *
+ * @param name Name of the service.
+ * @param work_q Pointer to workqueue where the work is done. Can be null in which case
+ *        system workqueue is used.
+ * @param cb Callback function that is called for socket activity.
+ * @param count How many pollable sockets is needed for this service.
+ */
+#define NET_SOCKET_SERVICE_ASYNC_DEFINE_STATIC(name, work_q, cb, count) \
+	__z_net_socket_service_define(name, work_q, cb, count, 1, static)
+
+/**
+ * @brief Statically define a network socket service.
+ *        The user callback is called synchronously for this service meaning that
+ *        the service API will wait until the user callback returns before continuing
+ *        with next socket service.
+ *
+ * The socket service can be accessed outside the module where it is defined using:
+ *
+ * @code extern struct net_socket_service_desc <name>; @endcode
+ *
+ * @note This macro cannot be used together with a static keyword.
+ *       If such a use-case is desired, use NET_SOCKET_SERVICE_SYNC_DEFINE_STATIC
+ *       instead.
+ *
+ * @param name Name of the service.
+ * @param work_q Pointer to workqueue where the work is done. Can be null in which case
+ *        system workqueue is used.
+ * @param cb Callback function that is called for socket activity.
+ * @param count How many pollable sockets is needed for this service.
+ */
+#define NET_SOCKET_SERVICE_SYNC_DEFINE(name, work_q, cb, count)	\
+	__z_net_socket_service_define(name, work_q, cb, count, 0)
+
+/**
+ * @brief Statically define a network socket service in a private (static) scope.
+ *        The user callback is called synchronously for this service meaning that
+ *        the service API will wait until the user callback returns before continuing
+ *        with next socket service.
+ *
+ * @param name Name of the service.
+ * @param work_q Pointer to workqueue where the work is done. Can be null in which case
+ *        system workqueue is used.
+ * @param cb Callback function that is called for socket activity.
+ * @param count How many pollable sockets is needed for this service.
+ */
+#define NET_SOCKET_SERVICE_SYNC_DEFINE_STATIC(name, work_q, cb, count)	\
+	__z_net_socket_service_define(name, work_q, cb, count, 0, static)
+
+/**
+ * @brief Register pollable sockets.
+ *
+ * @param service Pointer to a service description.
+ * @param fds Socket array to poll.
+ * @param len Length of the socket array.
+ * @param user_data User specific data.
+ *
+ * @retval 0 No error
+ * @retval -ENOENT Service is not found.
+ * @retval -ENINVAL Invalid parameter.
+ */
+__syscall int net_socket_service_register(const struct net_socket_service_desc *service,
+					  struct zsock_pollfd *fds, int len, void *user_data);
+
+/**
+ * @brief Unregister pollable sockets.
+ *
+ * @param service Pointer to a service description.
+ *
+ * @retval 0 No error
+ * @retval -ENOENT Service is not found.
+ * @retval -ENINVAL Invalid parameter.
+ */
+static inline int net_socket_service_unregister(const struct net_socket_service_desc *service)
+{
+	return net_socket_service_register(service, NULL, 0, NULL);
+}
+
+/**
+ * @typedef net_socket_service_cb_t
+ * @brief Callback used while iterating over socket services.
+ *
+ * @param svc Pointer to current socket service.
+ * @param user_data A valid pointer to user data or NULL
+ */
+typedef void (*net_socket_service_cb_t)(const struct net_socket_service_desc *svc,
+					void *user_data);
+
+/**
+ * @brief Go through all the socket services and call callback for each service.
+ *
+ * @param cb User-supplied callback function to call
+ * @param user_data User specified data
+ */
+void net_socket_service_foreach(net_socket_service_cb_t cb, void *user_data);
+
+#ifdef __cplusplus
+}
+#endif
+
+#include <syscalls/socket_service.h>
+
+/**
+ * @}
+ */
+
+#endif /* ZEPHYR_INCLUDE_NET_SOCKET_SERVICE_H_ */

samples/net/sockets/echo_service/CMakeLists.txt

@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(sockets_service_echo)
+
+FILE(GLOB app_sources src/*.c)
+target_sources(app PRIVATE ${app_sources})
+
+include(${ZEPHYR_BASE}/samples/net/common/common.cmake)

samples/net/sockets/echo_service/README.rst

@@ -0,0 +1,51 @@
+.. zephyr:code-sample:: sockets-service-echo
+   :name: Echo server (service)
+   :relevant-api: bsd_sockets
+
+   Implements a simple IPv4/IPv6 TCP echo server using BSD sockets and socket service API.
+
+Overview
+********
+
+The sockets/echo_service sample application for Zephyr implements a TCP echo
+server supporting both IPv4 and IPv6 and using a BSD Sockets compatible API.
+
+The purpose of this sample is to show how to use socket service API.
+The socket service is a concept where many blocking sockets can be listened by
+one thread, and which can then trigger a callback if there is activity in the set
+of sockets. This saves memory as only one thread needs to be created in the
+system.
+
+The application supports IPv4 and IPv6, and both UDP and TCP are also supported.
+The source code for this sample application can be found at:
+:zephyr_file:`samples/net/sockets/echo_service`.
+
+Requirements
+************
+
+- :ref:`networking_with_host`
+- or, a board with hardware networking
+
+Building and Running
+********************
+
+Build the Zephyr version of the sockets/echo_service application like this:
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/net/sockets/echo_service
+   :board: <board_to_use>
+   :goals: build
+   :compact:
+
+After the sample starts, it expects connections at 192.0.2.1, or 2001:db8::1
+and port 4242.
+The easiest way to connect is:
+
+.. code-block:: console
+
+    $ telnet 192.0.2.1 4242
+
+After a connection is made, the application will echo back any line sent
+to it. The application implements a single-threaded server using blocking
+sockets, and currently is only implemented to serve only one client connection
+at time. After the current client disconnects, the next connection can proceed.

samples/net/sockets/echo_service/overlay-e1000.conf

@@ -0,0 +1,6 @@
+# Overlay for experimental TCP as qemu_x86 with E1000
+
+CONFIG_PCIE=y
+
+CONFIG_NET_L2_ETHERNET=y
+CONFIG_NET_QEMU_ETHERNET=y

samples/net/sockets/echo_service/prj.conf

@@ -0,0 +1,38 @@
+# General config
+# The async method used in the sample needs more stack for the workqueue
+CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=1500
+CONFIG_POSIX_API=y
+
+# Networking config
+CONFIG_NETWORKING=y
+CONFIG_NET_IPV4=y
+CONFIG_NET_IPV6=y
+CONFIG_NET_TCP=y
+CONFIG_NET_SOCKETS=y
+CONFIG_NET_SOCKETS_POSIX_NAMES=y
+CONFIG_NET_IPV4_MAPPING_TO_IPV6=y
+CONFIG_POSIX_MAX_FDS=10
+CONFIG_NET_MAX_CONN=5
+CONFIG_NET_SOCKETS_SERVICE=y
+CONFIG_NET_SOCKETS_POLL_MAX=20
+
+# Network driver config
+CONFIG_TEST_RANDOM_GENERATOR=y
+
+# Network address config
+CONFIG_NET_CONFIG_SETTINGS=y
+CONFIG_NET_CONFIG_NEED_IPV4=y
+CONFIG_NET_CONFIG_NEED_IPV6=y
+CONFIG_NET_CONFIG_MY_IPV4_ADDR="192.0.2.1"
+CONFIG_NET_CONFIG_PEER_IPV4_ADDR="192.0.2.2"
+CONFIG_NET_CONFIG_MY_IPV6_ADDR="2001:db8::1"
+CONFIG_NET_CONFIG_PEER_IPV6_ADDR="2001:db8::2"
+
+# Network buffers
+CONFIG_NET_PKT_RX_COUNT=16
+CONFIG_NET_PKT_TX_COUNT=16
+CONFIG_NET_BUF_RX_COUNT=64
+CONFIG_NET_BUF_TX_COUNT=64
+CONFIG_NET_CONTEXT_NET_PKT_POOL=y
+
+CONFIG_NET_SHELL=y

samples/net/sockets/echo_service/sample.yaml

@@ -0,0 +1,16 @@
+sample:
+  description: echo server using socket service API
+  name: socket_service_echo
+common:
+  harness: net
+  depends_on: netif
+  filter: CONFIG_FULL_LIBC_SUPPORTED and not CONFIG_NATIVE_LIBC
+  # eventfd does not work properly with native_posix so exclude it here
+  platform_exclude:
+    - native_posix
+    - native_posix_64
+tests:
+  sample.net.sockets.service.echo:
+    tags:
+      - net
+      - socket