Improve networking (#4)

* Avoid redefinition warnings for CLOCK_MONOTONIC (#1)
* Support get/set for flags on socket fds
* Changes to support open62541 client/server
* Implement functions required for pub/sub
* Fix mismatch of enum sizes between WASM and host
* Improve zephyr sockets
* Add explanation comment

---------

Signed-off-by: Dan Kouba <dan@atym.io>
Signed-off-by: Krisztian Szilvasi <34309983+kr-t@users.noreply.github.com>
Co-authored-by: Dan Kouba <dan@atym.io>

Author: kr-t

core/shared/platform/include/platform_wasi_types.h

@@ -530,12 +530,6 @@ assert_wasi_layout(offsetof(__wasi_subscription_t, userdata) == 0, "witx calcula
 assert_wasi_layout(offsetof(__wasi_subscription_t, u) == 8, "witx calculated offset");
 
 /* keep syncing with wasi_socket_ext.h */
-typedef enum {
-    /* Used only for sock_addr_resolve hints */
-    SOCKET_ANY = -1,
-    SOCKET_DGRAM = 0,
-    SOCKET_STREAM,
-} __wasi_sock_type_t;
 
 typedef uint16_t __wasi_ip_port_t;
 
@@ -589,20 +583,36 @@ typedef struct __wasi_addr_t {
     } addr;
 } __wasi_addr_t;
 
-typedef enum { INET4 = 0, INET6, INET_UNSPEC } __wasi_address_family_t;
+/* Force 32-bit wire width for cross-boundary fields */
+typedef int32_t __wasi_sock_type_t;
+enum { SOCKET_ANY = -1, SOCKET_DGRAM = 0, SOCKET_STREAM = 1 };
+
+typedef int32_t __wasi_address_family_t;
+enum { INET4 = 0, INET6 = 1, INET_UNSPEC = 2 };
 
 typedef struct __wasi_addr_info_t {
-    __wasi_addr_t addr;
+    __wasi_addr_t      addr;
     __wasi_sock_type_t type;
 } __wasi_addr_info_t;
 
 typedef struct __wasi_addr_info_hints_t {
-   __wasi_sock_type_t type;
-   __wasi_address_family_t family;
-   // this is to workaround lack of optional parameters
-   uint8_t hints_enabled;
+    __wasi_sock_type_t        type;          // 4 bytes
+    __wasi_address_family_t   family;        // 4 bytes
+    uint8_t                   hints_enabled; // 1 byte
+    uint8_t                   _pad[3];       // enforce layout
 } __wasi_addr_info_hints_t;
 
+assert_wasi_layout(sizeof(__wasi_sock_type_t) == 4, "sock_type must be 4 bytes");
+assert_wasi_layout(sizeof(__wasi_address_family_t) == 4, "addr_family must be 4 bytes");
+
+assert_wasi_layout(sizeof(__wasi_addr_info_hints_t) == 12, "hints_t must be 12 bytes");
+assert_wasi_layout(offsetof(__wasi_addr_info_hints_t, type) == 0, "hints.type@0");
+assert_wasi_layout(offsetof(__wasi_addr_info_hints_t, family) == 4, "hints.family@4");
+assert_wasi_layout(offsetof(__wasi_addr_info_hints_t, hints_enabled) == 8, "hints.enabled@8");
+
+assert_wasi_layout(offsetof(__wasi_addr_info_t, type) == sizeof(__wasi_addr_t),
+                   "addr_info.type follows addr");
+
 #undef assert_wasi_layout
 
 /* clang-format on */

core/shared/platform/zephyr/platform_internal.h

@@ -290,7 +290,9 @@ typedef struct timespec os_timespec;
 #define CLOCK_REALTIME 1
 #endif
 
+#ifndef CLOCK_MONOTONIC
 #define CLOCK_MONOTONIC 4
+#endif
 
 static inline int
 os_sched_yield(void)

core/shared/platform/zephyr/zephyr_file.c

@@ -15,6 +15,9 @@
 #include <zephyr/fs/fs_sys.h>
 #include <zephyr/fs/littlefs.h>
 
+#include <zephyr/net/socket.h>
+#include <zephyr/posix/fcntl.h> // F_GETFL, F_SETFL, O_NONBLOCK
+
 /* Notes:
  * This is the implementation of a POSIX-like file system interface for Zephyr.
  * To manage our file descriptors, we created a struct `zephyr_fs_desc` that
@@ -273,6 +276,16 @@ os_file_get_fdflags(os_file_handle handle, __wasi_fdflags_t *flags)
 {
     struct zephyr_fs_desc *ptr = NULL;
 
+    /* Sockets: reflect current non-blocking state */
+    if (handle->is_sock) {
+        int cur = zsock_fcntl(handle->fd, F_GETFL, 0);
+        if (cur < 0)
+            return convert_errno(errno);
+        if (cur & O_NONBLOCK)
+            *flags |= __WASI_FDFLAG_NONBLOCK;
+        return __WASI_ESUCCESS;
+    }
+
     if (os_is_virtual_fd(handle->fd)) {
         *flags = 0;
         return __WASI_ESUCCESS;
@@ -296,6 +309,21 @@ os_file_get_fdflags(os_file_handle handle, __wasi_fdflags_t *flags)
 __wasi_errno_t
 os_file_set_fdflags(os_file_handle handle, __wasi_fdflags_t flags)
 {
+    /* Sockets: set/clear O_NONBLOCK */
+    if (handle->is_sock) {
+        int cur = zsock_fcntl(handle->fd, F_GETFL, 0);
+        if (cur < 0)
+            return convert_errno(errno);
+
+        bool want_nb = (flags & __WASI_FDFLAG_NONBLOCK) != 0;
+        int newf = want_nb ? (cur | O_NONBLOCK) : (cur & ~O_NONBLOCK);
+
+        if (zsock_fcntl(handle->fd, F_SETFL, newf) < 0) {
+            return convert_errno(errno);
+        }
+        return __WASI_ESUCCESS;
+    }
+
     if (os_is_virtual_fd(handle->fd)) {
         return __WASI_ESUCCESS;
     }
@@ -1195,4 +1223,4 @@ bool
 os_is_stderr_handle(os_file_handle handle)
 {
     return (handle == (os_file_handle)stderr);
-}
+}