implemented socket_TCP_enableAliveChecks

src/network/internal.h

@@ -13,6 +13,7 @@
 // include OS-dependent socket headers
 #if KN_USE_WINSOCK
     #include <winsock2.h>
+    #include <ws2ipdef.h>
     // There you can see what error codes mean.
     #include <winerror.h>
 #else

src/network/network.c

@@ -13,13 +13,9 @@ Result(void) network_init(){
     return RESULT_VOID;
 }
 
-Result(void) network_deinit(){
+void network_deinit(){
 #if _WIN32
     // Deinitialize Winsock
-    int result = WSACleanup();
-    if (result != 0) {
-        return RESULT_ERROR_FMT("WSACleanup failed with error code 0x%X", result);
-    }
+    (void)WSACleanup();
 #endif
-    return RESULT_VOID;
 }

src/network/network.h

@@ -2,4 +2,4 @@
 #include "tlibc/errors.h"
 
 Result(void) network_init();
-Result(void) network_deinit();
+void network_deinit();

src/network/socket.c

@@ -3,7 +3,7 @@
 #include <assert.h>
 
 Result(Socket) socket_open_TCP(){
-    Socket s = socket(AF_INET, SOCK_STREAM, 0);
+    Socket s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
     if(s == -1){
         return RESULT_ERROR_SOCKET();
     }
@@ -25,29 +25,6 @@ Result(void) socket_shutdown(Socket s, SocketShutdownType direction){
     return RESULT_VOID;
 }
 
-Result(void) socket_setTimeout(Socket s, u32 ms){
-    void* opt;
-    u32 optlen;
-
-#if KN_USE_WINSOCK
-    opt = &ms;
-    optlen = sizeof(ms);
-#else
-    struct timeval tv = {
-        .tv_sec = ms/1000,
-        .tv_usec = (ms%1000)*1000
-    };
-    opt = &tv;
-    optlen = sizeof(tv);
-#endif
-
-    if(setsockopt(s, SOL_SOCKET, SO_SNDTIMEO, opt, optlen) != 0)
-        return RESULT_ERROR_SOCKET();
-    if(setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, opt, optlen) != 0)
-        return RESULT_ERROR_SOCKET();
-    return RESULT_VOID;
-}
-
 Result(void) socket_bind(Socket s, EndpointIPv4 local_end){
     struct sockaddr_in sockaddr = EndpointIPv4_toSockaddr(local_end);
     if(bind(s, (void*)&sockaddr, sizeof(sockaddr)) != 0)
@@ -146,3 +123,60 @@ Result(i32) socket_recvfrom(Socket s, Array(u8) buffer, SocketRecvFlag flags, NU
         *remote_end = EndpointIPv4_fromSockaddr(remote_addr);
     return RESULT_VALUE(i, r);
 }
+
+
+
+#define try_setsockopt(socket, level, OPT){ \
+    if(setsockopt(socket, level, OPT, (void*)&opt_##OPT, sizeof(opt_##OPT)) != 0)\
+        return RESULT_ERROR_SOCKET();\
+}
+
+Result(void) socket_TCP_enableAliveChecks(Socket s,
+    sec_t first_check_time, u32 checks_count, sec_t checks_interval)
+{
+#if KN_USE_WINSOCK
+    BOOL opt_SO_KEEPALIVE = 1; // enable keepalives
+    DWORD opt_TCP_KEEPIDLE = first_check_time;
+    DWORD opt_TCP_KEEPCNT = checks_count;
+    DWORD opt_TCP_KEEPINTVL = checks_interval;
+    try_setsockopt(s, SOL_SOCKET, SO_KEEPALIVE);
+    try_setsockopt(s, IPPROTO_TCP, TCP_KEEPIDLE);
+    try_setsockopt(s, IPPROTO_TCP, TCP_KEEPCNT);
+    try_setsockopt(s, IPPROTO_TCP, TCP_KEEPINTVL);
+
+    // timeout for connect() 
+    DWORD opt_TCP_MAXRT = checks_count * checks_interval; 
+    try_setsockopt(s, IPPROTO_TCP, TCP_MAXRT);
+#else
+    int opt_SO_KEEPALIVE = 1; // enable keepalives
+    int opt_TCP_KEEPIDLE = first_check_time;
+    int opt_TCP_KEEPCNT = checks_count;
+    int opt_TCP_KEEPINTVL = checks_interval;
+    try_setsockopt(s, SOL_SOCKET, SO_KEEPALIVE);
+    try_setsockopt(s, IPPROTO_TCP, TCP_KEEPIDLE);
+    try_setsockopt(s, IPPROTO_TCP, TCP_KEEPCNT);
+    try_setsockopt(s, IPPROTO_TCP, TCP_KEEPINTVL);
+
+    // read more in the article
+    int opt_TCP_USER_TIMEOUT = checks_count * checks_interval * 1000;
+    try_setsockopt(s, IPPROTO_TCP, TCP_USER_TIMEOUT);
+#endif
+    return RESULT_VOID;
+}
+
+Result(void) socket_setTimeout(Socket s, u32 ms){
+#if KN_USE_WINSOCK
+    DWORD opt_SO_SNDTIMEO = ms;
+    DWORD opt_SO_RCVTIMEO = opt_SO_SNDTIMEO;
+#else
+    struct timeval opt_SO_SNDTIMEO = {
+        .tv_sec = ms/1000,
+        .tv_usec = (ms%1000)*1000
+    };
+    struct timeval opt_SO_RCVTIMEO = opt_SO_SNDTIMEO;
+#endif
+
+    try_setsockopt(s, SOL_SOCKET, SO_SNDTIMEO);
+    try_setsockopt(s, SOL_SOCKET, SO_RCVTIMEO);
+    return RESULT_VOID;
+}

src/network/socket.h

@@ -1,6 +1,7 @@
 #pragma once
 #include "endpoint.h"
 #include "tlibc/errors.h"
+#include "tlibc/time.h"
 #include "tlibc/collections/Array.h"
 
 typedef enum SocketShutdownType {
@@ -17,13 +18,9 @@ typedef enum SocketRecvFlag {
 
 typedef i64 Socket;
 
-#define SOCKET_TIMEOUT_MS_DEFAULT 5000
-#define SOCKET_TIMEOUT_MS_INFINITE 0
-
 Result(Socket)  socket_open_TCP();
 void            socket_close(Socket s);
 Result(void)    socket_shutdown(Socket s, SocketShutdownType direction);
-Result(void)    socket_setTimeout(Socket s, u32 ms);
 
 Result(void)    socket_bind(Socket s, EndpointIPv4 local_end);
 Result(void)    socket_listen(Socket s, i32 backlog);
@@ -34,3 +31,18 @@ Result(void)    socket_send(Socket s, Array(u8) buffer);
 Result(void)    socket_sendto(Socket s, Array(u8) buffer, EndpointIPv4 dst);
 Result(i32)     socket_recv(Socket s, Array(u8) buffer, SocketRecvFlag flags);
 Result(i32)     socket_recvfrom(Socket s, Array(u8) buffer, SocketRecvFlag flags, NULLABLE(EndpointIPv4*) remote_end);
+
+/// Enables sending SO_KEEPALIVE packets when socket is idling.
+/// Also enables TCP_USER_TIMEOUT to handle situations 
+/// when socket is not sending KEEPALIVE packets.
+/// Read more: https://blog.cloudflare.com/when-tcp-sockets-refuse-to-die/
+/// RU translaton: https://habr.com/ru/articles/700470/
+Result(void) socket_TCP_enableAliveChecks(Socket s,
+    sec_t first_check_time, u32 checks_count, sec_t checks_interval);
+#define socket_TCP_enableAliveChecks_default(socket) \
+    socket_TCP_enableAliveChecks(socket, 1, 4, 5)
+
+#define SOCKET_TIMEOUT_MS_DEFAULT 5000
+#define SOCKET_TIMEOUT_MS_INFINITE 0
+/// @brief sets general timeout for send() and recv()  
+Result(void) socket_setTimeout(Socket s, u32 ms);