win32: socket: use winsock2.h instead of sys/socket.h

Windows has no POSIX sockets. Use the Windows provided winsock2.h
instead.

- include winsocket
- call WSAStartup and WSACleanup
- use SOCKET as file descriptor
- compare to INVALID_SOCKET or SOCKET_ERROR as recommended
- modify optflag type for setsockopts()

src/common/socket.c

@@ -21,17 +21,25 @@
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
+#ifndef _WIN32
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <sys/poll.h>
+#else // _WIN32
+#include <winsock2.h>
+#endif
 #include <unistd.h>
 #include "common/logger.h"
 
 struct socket_t
 {
     struct socket_config_t  config;
+#ifndef _WIN32
     int                     fd;
+#else // _WIN32
+    SOCKET fd;
+#endif
 };
 
 static int socket_open(socket_handle_t handle);
@@ -54,6 +62,16 @@ int socket_init(socket_handle_t* handle, struct socket_config_t const* config)
         logger_log(LOG_FATAL, "%s: could not allocate memory", __func__);
         return -ENOMEM;
     }
+#ifdef _WIN32
+    WSADATA wsadata;
+    ret = WSAStartup(MAKEWORD(2,2), &wsadata);
+    if (ret != 0)
+    {
+        logger_log(LOG_FATAL, "%s: WSAStartup failed: %d", __func__, ret);
+        return -EINVAL;
+    }
+    (*handle)->fd = INVALID_SOCKET;
+#endif
 
     (*handle)->config = *config;
 
@@ -82,6 +100,9 @@ int socket_release(socket_handle_t* handle)
         free(*handle);
         *handle = 0;
     }
+#ifdef _WIN32
+    WSACleanup();
+#endif
 
     return ret;
 }
@@ -94,7 +115,21 @@ int socket_is_broadcast_address(char const* ip)
 int socket_open(socket_handle_t handle)
 {
     int ret = 0;
+#ifndef _WIN32
     int optflag = 0;
+#else // _WIN32
+    // optflag is used as optval for setsockopt(), windows expects it to be a char
+    // posix expects a void *
+    // from https://docs.microsoft.com/en-us/windows/win32/api/winsock/nf-winsock-setsockopt
+    // int setsockopt(
+    //   SOCKET     s,
+    //   int        level,
+    //   int        optname,
+    //   const char *optval,
+    //   int        optlen
+    // );
+    char optflag = 0;
+#endif
     struct sockaddr_in si_me;
 
     if (handle == 0)
@@ -105,7 +140,11 @@ int socket_open(socket_handle_t handle)
 
     logger_log(LOG_INFO, "%s: opening socket with port %d", __func__, handle->config.port);
 
+#ifndef _WIN32
     if (handle->fd != 0)
+#else // _WIN32
+    if (handle->fd != INVALID_SOCKET)
+#endif
     {
         ret = socket_close(handle);
         if (ret != 0)
@@ -116,6 +155,7 @@ int socket_open(socket_handle_t handle)
     }
 
     handle->fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+#ifndef _WIN32
     if (handle->fd < 0)
     {
         logger_log(LOG_ERROR, "%s: unable to create socket", __func__);
@@ -123,6 +163,15 @@ int socket_open(socket_handle_t handle)
         handle->fd = 0;
         return ret;
     }
+#else // _WIN32
+    if (handle->fd == INVALID_SOCKET)
+    {
+        logger_log(LOG_ERROR, "%s: unable to create socket", __func__);
+        ret = -1;
+        handle->fd = INVALID_SOCKET;
+        return ret;
+    }
+#endif
     
     if (handle->config.direction == SOCKET_IN)
     {
@@ -132,11 +181,19 @@ int socket_open(socket_handle_t handle)
         si_me.sin_addr.s_addr   = htonl(INADDR_ANY);
         ret = bind(handle->fd, (struct sockaddr const*)&si_me, sizeof(si_me));
 
+#ifndef _WIN32
         if (ret < 0)
+#else // _WIN32
+        if (ret == SOCKET_ERROR)
+#endif
         {
             logger_log(LOG_ERROR, "%s: unable to bind socket", __func__);
             socket_close(handle);
+#ifndef _WIN32
             return errno;
+#else // _WIN32
+            return WSAGetLastError();
+#endif
         }
     }
     else
@@ -172,11 +229,19 @@ int socket_close(socket_handle_t handle)
 
     logger_log(LOG_INFO, "%s: closing socket with port %d", __func__, handle->config.port);
 
+#ifndef _WIN32
     if (handle->fd != 0)
+#else // _WIN32
+    if (handle->fd == INVALID_SOCKET)
+#endif
     {
         ret = close(handle->fd);
         handle->fd = 0;
+#ifndef _WIN32
         if (ret != 0)
+#else // _WIN32
+        if (ret == SOCKET_ERROR)
+#endif
         {
             logger_log(LOG_ERROR, "%s: unable to close socket", __func__);
             return ret;
@@ -190,7 +255,11 @@ int socket_read(socket_handle_t handle, char* buffer, size_t size)
 {
     int ret = 0;
     struct sockaddr_in si_other;
+#ifndef _WIN32
     socklen_t slen = sizeof(si_other);
+#else // _WIN32
+    int slen = sizeof(si_other);
+#endif
 
     logger_log(LOG_DEBUG, "%s invoked", __func__);
 
@@ -202,7 +271,11 @@ int socket_read(socket_handle_t handle, char* buffer, size_t size)
 
     logger_log(LOG_DEBUG, "%s ip %s", __func__, handle->config.ip_address);
 
+#ifndef _WIN32
     if (handle->fd == 0)
+#else // _WIN32
+    if (handle->fd == INVALID_SOCKET)
+#endif
     {
         logger_log(LOG_ERROR, "%s: socket is not open", __func__);
         return -ENODEV;
@@ -232,7 +305,11 @@ int socket_write(socket_handle_t handle, char const* buffer, size_t size)
 {
     int ret = 0;
     struct sockaddr_in si_other;
+#ifndef _WIN32
     socklen_t slen = sizeof(si_other);
+#else // _WIN32
+    int slen = sizeof(si_other);
+#endif
 
     logger_log(LOG_DEBUG, "%s invoked", __func__);