net: sockets: Remove socket offloading interface

Instead of using a custom offloading interface, users can use
`NET_SOCKET_REGISTER` macro to register custom socket API provider. This
solution removes a limitation, that only one offloaded interface can be
registered and that it cannot be used together with native IP stack.

The only exception remainig are DNS releated operations -
`getaddrinfo`/`freeaddrinfo`, which, when offloaded, have to be
registered specifically.

Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>

doc/reference/networking/net_offload.rst

@@ -39,9 +39,3 @@ networking devices, can easily integrate it with Zephyr.
 
 See :zephyr_file:`drivers/wifi/simplelink/simplelink_sockets.c` for a sample
 implementation on how to integrate network offloading at socket level.
-
-API Reference
-*************
-
-.. doxygengroup:: socket_offload
-   :project: Zephyr

include/net/socket.h

@@ -507,10 +507,7 @@ int zsock_getaddrinfo(const char *host, const char *service,
  * if :option:`CONFIG_NET_SOCKETS_POSIX_NAMES` is defined.
  * @endrst
  */
-static inline void zsock_freeaddrinfo(struct zsock_addrinfo *ai)
+void zsock_freeaddrinfo(struct zsock_addrinfo *ai);
-{
-	free(ai);
-}
 
 /**
  * @brief Convert zsock_getaddrinfo() error code to textual message
@@ -564,7 +561,6 @@ int zsock_getnameinfo(const struct sockaddr *addr, socklen_t addrlen,
 
 #define pollfd zsock_pollfd
 
-#if !defined(CONFIG_NET_SOCKETS_OFFLOAD)
 static inline int socket(int family, int type, int proto)
 {
 	return zsock_socket(family, type, proto);
@@ -693,42 +689,12 @@ static inline int inet_pton(sa_family_t family, const char *src, void *dst)
 	return zsock_inet_pton(family, src, dst);
 }
 
-#else
+static inline char *inet_ntop(sa_family_t family, const void *src, char *dst,
-
+			      size_t size)
-struct addrinfo {
-	int ai_flags;
-	int ai_family;
-	int ai_socktype;
-	int ai_protocol;
-	socklen_t ai_addrlen;
-	struct sockaddr *ai_addr;
-	char *ai_canonname;
-	struct addrinfo *ai_next;
-};
-
-/* Legacy case: retain containing extern "C" with C++
- *
- * This header requires aliases defined within this file, and can't
- * easily be moved to the top.
- */
-#include <net/socket_offload.h>
-
-static inline int inet_pton(sa_family_t family, const char *src, void *dst)
 {
-	if ((family != AF_INET) && (family != AF_INET6)) {
+	return zsock_inet_ntop(family, src, dst, size);
-		errno = EAFNOSUPPORT;
-		return -1;
-	}
-
-	if (net_addr_pton(family, src, dst) == 0) {
-		return 1;
-	} else {
-		return 0;
-	}
 }
 
-#endif /* !defined(CONFIG_NET_SOCKETS_OFFLOAD) */
-
 #define POLLIN ZSOCK_POLLIN
 #define POLLOUT ZSOCK_POLLOUT
 #define POLLERR ZSOCK_POLLERR
@@ -742,12 +708,6 @@ static inline int inet_pton(sa_family_t family, const char *src, void *dst)
 #define SHUT_WR ZSOCK_SHUT_WR
 #define SHUT_RDWR ZSOCK_SHUT_RDWR
 
-static inline char *inet_ntop(sa_family_t family, const void *src, char *dst,
-			      size_t size)
-{
-	return zsock_inet_ntop(family, src, dst, size);
-}
-
 #define EAI_BADFLAGS DNS_EAI_BADFLAGS
 #define EAI_NONAME DNS_EAI_NONAME
 #define EAI_AGAIN DNS_EAI_AGAIN

include/net/socket_offload.h

@@ -12,153 +12,38 @@
 #ifndef ZEPHYR_INCLUDE_NET_SOCKET_OFFLOAD_H_
 #define ZEPHYR_INCLUDE_NET_SOCKET_OFFLOAD_H_
 
-#include <net/socket_offload_ops.h>
+#include <net/net_ip.h>
+#include <net/socket.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-extern const struct socket_offload *socket_ops;
+/**
+ * @brief An offloaded Socket DNS API interface
+ *
+ * It is assumed that these offload functions follow the
+ * POSIX socket API standard for arguments, return values and setting of errno.
+ */
+struct socket_dns_offload {
+	int (*getaddrinfo)(const char *node, const char *service,
+			   const struct zsock_addrinfo *hints,
+			   struct zsock_addrinfo **res);
+	void (*freeaddrinfo)(struct zsock_addrinfo *res);
+};
 
-static inline int socket(int family, int type, int proto)
+/**
-{
+ * @brief Register an offloaded socket DNS API interface.
-	__ASSERT_NO_MSG(socket_ops);
+ *
-	__ASSERT_NO_MSG(socket_ops->socket);
+ * @param ops A pointer to the offloaded socket DNS API interface.
+ */
+void socket_offload_dns_register(const struct socket_dns_offload *ops);
 
-	return socket_ops->socket(family, type, proto);
+int socket_offload_getaddrinfo(const char *node, const char *service,
-}
+			       const struct zsock_addrinfo *hints,
+			       struct zsock_addrinfo **res);
 
-static inline int close(int sock)
+void socket_offload_freeaddrinfo(struct zsock_addrinfo *res);
-{
-	__ASSERT_NO_MSG(socket_ops);
-	__ASSERT_NO_MSG(socket_ops->close);
-
-	return socket_ops->close(sock);
-}
-
-static inline int accept(int sock, struct sockaddr *addr,
-			 socklen_t *addrlen)
-{
-	__ASSERT_NO_MSG(socket_ops);
-	__ASSERT_NO_MSG(socket_ops->accept);
-
-	return socket_ops->accept(sock, addr, addrlen);
-}
-
-
-static inline int bind(int sock, const struct sockaddr *addr,
-		       socklen_t addrlen)
-{
-	__ASSERT_NO_MSG(socket_ops);
-	__ASSERT_NO_MSG(socket_ops->bind);
-
-	return socket_ops->bind(sock, addr, addrlen);
-}
-
-static inline int listen(int sock, int backlog)
-{
-	__ASSERT_NO_MSG(socket_ops);
-	__ASSERT_NO_MSG(socket_ops->listen);
-
-	return socket_ops->listen(sock, backlog);
-}
-
-static inline int connect(int sock, const struct sockaddr *addr,
-			  socklen_t addrlen)
-{
-	__ASSERT_NO_MSG(socket_ops);
-	__ASSERT_NO_MSG(socket_ops->connect);
-
-	return socket_ops->connect(sock, addr, addrlen);
-}
-
-static inline int poll(struct pollfd *fds, int nfds, int timeout)
-{
-	__ASSERT_NO_MSG(socket_ops);
-	__ASSERT_NO_MSG(socket_ops->poll);
-
-	return socket_ops->poll(fds, nfds, timeout);
-}
-
-static inline int setsockopt(int sock, int level, int optname,
-			     const void *optval,
-			     socklen_t optlen)
-{
-	__ASSERT_NO_MSG(socket_ops);
-	__ASSERT_NO_MSG(socket_ops->setsockopt);
-
-	return socket_ops->setsockopt(sock, level, optname, optval, optlen);
-}
-
-static inline int getsockopt(int sock, int level, int optname,
-			     void *optval, socklen_t *optlen)
-{
-	__ASSERT_NO_MSG(socket_ops);
-	__ASSERT_NO_MSG(socket_ops->getsockopt);
-
-	return socket_ops->getsockopt(sock, level, optname, optval, optlen);
-}
-
-static inline ssize_t recv(int sock, void *buf, size_t max_len,
-				      int flags)
-{
-	__ASSERT_NO_MSG(socket_ops);
-	__ASSERT_NO_MSG(socket_ops->recv);
-
-	return socket_ops->recv(sock, buf, max_len, flags);
-}
-
-static inline ssize_t recvfrom(int sock, void *buf,
-			       short int len,
-			       short int flags,
-			       struct sockaddr *from,
-			       socklen_t *fromlen)
-{
-	__ASSERT_NO_MSG(socket_ops);
-	__ASSERT_NO_MSG(socket_ops->recvfrom);
-
-	return socket_ops->recvfrom(sock, buf, len, flags, from, fromlen);
-}
-
-static inline ssize_t send(int sock, const void *buf, size_t len,
-			   int flags)
-{
-	__ASSERT_NO_MSG(socket_ops);
-	__ASSERT_NO_MSG(socket_ops->send);
-
-	return socket_ops->send(sock, buf, len, flags);
-}
-
-static inline ssize_t sendto(int sock, const void *buf,
-			     size_t len, int flags,
-			     const struct sockaddr *to,
-			     socklen_t tolen)
-{
-	__ASSERT_NO_MSG(socket_ops);
-	__ASSERT_NO_MSG(socket_ops->sendto);
-
-	return socket_ops->sendto(sock, buf, len, flags, to, tolen);
-}
-
-static inline int getaddrinfo(const char *node, const char *service,
-			      const struct addrinfo *hints,
-			      struct addrinfo **res)
-{
-	__ASSERT_NO_MSG(socket_ops);
-	__ASSERT_NO_MSG(socket_ops->getaddrinfo);
-
-	return socket_ops->getaddrinfo(node, service, hints, res);
-}
-
-static inline void freeaddrinfo(struct addrinfo *res)
-{
-	__ASSERT_NO_MSG(socket_ops);
-	__ASSERT_NO_MSG(socket_ops->freeaddrinfo);
-
-	return socket_ops->freeaddrinfo(res);
-}
-
-int fcntl(int fd, int cmd, ...);
 
 #ifdef __cplusplus
 }

include/net/socket_offload_ops.h

@@ -1,79 +0,0 @@
-/*
- * Copyright (c) 2018 Linaro Limited.
- *
- * SPDX-License-Identifier: Apache-2.0
- */
-
-/**
- * @file
- * @brief Socket Offload Redirect API
- */
-
-#ifndef ZEPHYR_INCLUDE_NET_SOCKET_OFFLOAD_OPS_H_
-#define ZEPHYR_INCLUDE_NET_SOCKET_OFFLOAD_OPS_H_
-
-#include <sys/types.h>
-#include <net/net_ip.h>
-#include <net/socket.h>  /* needed for struct pollfd */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-/**
- * @brief Socket Offload Redirect API
- * @defgroup socket_offload Socket offloading interface
- * @ingroup networking
- * @{
- */
-
-/**
- * @brief An offloaded Socket API interface
- *
- * It is assumed that these offload functions follow the
- * POSIX socket API standard for arguments, return values and setting of errno.
- */
-struct socket_offload {
-	/* POSIX Socket Functions: */
-	int (*socket)(int family, int type, int proto);
-	int (*close)(int sock);
-	int (*accept)(int sock, struct sockaddr *addr, socklen_t *addrlen);
-	int (*bind)(int sock, const struct sockaddr *addr, socklen_t addrlen);
-	int (*listen)(int sock, int backlog);
-	int (*connect)(int sock, const struct sockaddr *addr,
-		       socklen_t addrlen);
-	int (*poll)(struct pollfd *fds, int nfds, int timeout);
-	int (*setsockopt)(int sock, int level, int optname,
-			  const void *optval, socklen_t optlen);
-	int (*getsockopt)(int sock, int level, int optname, void *optval,
-			  socklen_t *optlen);
-	ssize_t (*recv)(int sock, void *buf, size_t max_len, int flags);
-	ssize_t (*recvfrom)(int sock, void *buf, short int len,
-			    short int flags, struct sockaddr *from,
-			    socklen_t *fromlen);
-	ssize_t (*send)(int sock, const void *buf, size_t len, int flags);
-	ssize_t (*sendto)(int sock, const void *buf, size_t len, int flags,
-			  const struct sockaddr *to, socklen_t tolen);
-	int (*getaddrinfo)(const char *node, const char *service,
-			   const struct addrinfo *hints,
-			   struct addrinfo **res);
-	void (*freeaddrinfo)(struct addrinfo *res);
-	int (*fcntl)(int fd, int cmd, va_list args);
-};
-
-/**
- * @brief Register an offloaded socket API interface.
- *
- * @param ops A pointer to the offloaded socket API interface.
- */
-extern void socket_offload_register(const struct socket_offload *ops);
-
-/**
- * @}
- */
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif /* ZEPHYR_INCLUDE_NET_SOCKET_OFFLOAD_OPS_H_ */

subsys/net/lib/sockets/CMakeLists.txt

@@ -2,12 +2,15 @@
 
 zephyr_include_directories(.)
 
-if(NOT CONFIG_NET_SOCKETS_OFFLOAD)
 zephyr_sources(
   getaddrinfo.c
-  getnameinfo.c
   sockets.c
+)
+
+if(NOT CONFIG_NET_SOCKETS_OFFLOAD)
+zephyr_sources(
   sockets_select.c
+  getnameinfo.c
   sockets_misc.c
   )
 zephyr_sources_ifdef(CONFIG_NET_SOCKETS_SOCKOPT_TLS sockets_tls.c)

subsys/net/lib/sockets/getaddrinfo.c

@@ -14,6 +14,7 @@ LOG_MODULE_REGISTER(net_sock_addr, CONFIG_NET_SOCKETS_LOG_LEVEL);
 
 #include <kernel.h>
 #include <net/socket.h>
+#include <net/socket_offload.h>
 #include <syscall_handler.h>
 
 #define AI_ARR_MAX	2
@@ -320,10 +321,17 @@ out:
 #include <syscalls/z_zsock_getaddrinfo_internal_mrsh.c>
 #endif /* CONFIG_USERSPACE */
 
+#endif /* defined(CONFIG_DNS_RESOLVER) */
+
 int zsock_getaddrinfo(const char *host, const char *service,
 		      const struct zsock_addrinfo *hints,
 		      struct zsock_addrinfo **res)
 {
+	if (IS_ENABLED(CONFIG_NET_SOCKETS_OFFLOAD)) {
+		return socket_offload_getaddrinfo(host, service, hints, res);
+	}
+
+#if defined(CONFIG_DNS_RESOLVER)
 	int ret;
 
 	*res = calloc(AI_ARR_MAX, sizeof(struct zsock_addrinfo));
@@ -336,6 +344,18 @@ int zsock_getaddrinfo(const char *host, const char *service,
 		*res = NULL;
 	}
 	return ret;
+#endif
+
+	return DNS_EAI_FAIL;
+}
+
+void zsock_freeaddrinfo(struct zsock_addrinfo *ai)
+{
+	if (IS_ENABLED(CONFIG_NET_SOCKETS_OFFLOAD)) {
+		return socket_offload_freeaddrinfo(ai);
+	}
+
+	free(ai);
 }
 
 #define ERR(e) case DNS_ ## e: return #e
@@ -356,5 +376,3 @@ const char *zsock_gai_strerror(int errcode)
 	}
 }
 #undef ERR
-
-#endif

subsys/net/lib/sockets/socket_offload.c

@@ -8,29 +8,34 @@
 LOG_MODULE_REGISTER(net_socket_offload, CONFIG_NET_SOCKETS_LOG_LEVEL);
 
 #include <net/socket_offload.h>
+#include <net/socket.h>
 
-/* Only one provider may register socket operations upon boot. */
+#include "sockets_internal.h"
-const struct socket_offload *socket_ops;
 
-void socket_offload_register(const struct socket_offload *ops)
+const struct socket_dns_offload *dns_offload;
+
+void socket_offload_dns_register(const struct socket_dns_offload *ops)
 {
 	__ASSERT_NO_MSG(ops);
-	__ASSERT_NO_MSG(socket_ops == NULL);
+	__ASSERT_NO_MSG(dns_offload == NULL);
 
-	socket_ops = ops;
+	dns_offload = ops;
 }
 
-int fcntl(int fd, int cmd, ...)
+int socket_offload_getaddrinfo(const char *node, const char *service,
+			       const struct zsock_addrinfo *hints,
+			       struct zsock_addrinfo **res)
 {
-	__ASSERT_NO_MSG(socket_ops);
+	__ASSERT_NO_MSG(dns_offload);
-	__ASSERT_NO_MSG(socket_ops->fcntl);
+	__ASSERT_NO_MSG(dns_offload->getaddrinfo);
 
-	va_list args;
+	return dns_offload->getaddrinfo(node, service, hints, res);
-	int res;
+}
-
+
-	va_start(args, cmd);
+void socket_offload_freeaddrinfo(struct zsock_addrinfo *res)
-	res = socket_ops->fcntl(fd, cmd, args);
+{
-	va_end(args);
+	__ASSERT_NO_MSG(dns_offload);
-
+	__ASSERT_NO_MSG(dns_offload->freeaddrinfo);
-	return res;
+
+	return dns_offload->freeaddrinfo(res);
 }

subsys/net/lib/sockets/sockets.c

@@ -164,7 +164,12 @@ int z_impl_zsock_socket(int family, int type, int proto)
 		return sock_family->handler(family, type, proto);
 	}
 
-	return zsock_socket_internal(family, type, proto);
+	if (IS_ENABLED(CONFIG_NET_NATIVE)) {
+		return zsock_socket_internal(family, type, proto);
+	}
+
+	errno = EAFNOSUPPORT;
+	return -1;
 }
 
 #ifdef CONFIG_USERSPACE