Fix socket draining / lingering

(cherry picked from commit 1cea4fef4b,
without httpsrv.c, which 0.9 does not have)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/common.c

@@ -414,7 +414,6 @@ int
 	return shutdown(s, how);
     }
     int WINAPI def_closesocket(void* state, SOCKET s){
-	usleep(SLEEPTIME);
 	return closesocket(s);
     }
 #else
@@ -736,7 +735,9 @@ int doconnect(struct clientparam * param){
 	if(param->srv->so._getpeername(param->sostate, param->remsock, (struct sockaddr *)&param->sinsr, &size)==-1) {return (14);}
  }
  else {
+#ifndef _WIN32
 	struct linger lg = {1,conf.timeouts[LINGER_TO]};
+#endif
 
 	if(SAISNULL(&param->sinsr)){
 		if(SAISNULL(&param->req)) {
@@ -766,7 +767,10 @@ int doconnect(struct clientparam * param){
 	*SAPORT(&param->sinsl) = 0;
 	setopts(param->remsock, param->srv->srvsockopts);
 
+#ifndef _WIN32
+	/* not on Windows, see the accepting side in proxymain.c */
 	param->srv->so._setsockopt(param->sostate, param->remsock, SOL_SOCKET, SO_LINGER, (char *)&lg, sizeof(lg));
+#endif
 	if(extbindtodevice(param, param->remsock)) return 12;
 #ifdef WITH_UN
 	if(*SAFAMILY(&param->sinsl) != AF_UNIX)

src/ftppr.c

@@ -21,14 +21,18 @@ void * ftpprchild(struct clientparam* param) {
  SOCKET sc = INVALID_SOCKET, ss = INVALID_SOCKET, clidatasock = INVALID_SOCKET;
  SASIZETYPE sasize;
  char * req = NULL;
+#ifndef _WIN32
  struct linger lg;
+#endif
  struct pollfd fds;
 
  if(!(buf = malloc(BUFSIZE))) RETURN(876);
  param->ctrlsock = param->clisock;
  param->operation = CONNECT;
+#ifndef _WIN32
  lg.l_onoff = 1;
- lg.l_linger = conf.timeouts[STRING_L];;
+ lg.l_linger = conf.timeouts[STRING_L];
+#endif
  if(socksend(param, param->ctrlsock, (unsigned char *)"220 Ready\r\n", 11, conf.timeouts[STRING_S])!=11) {RETURN (801);}
  for(;;){
 	i = sockgetlinebuf(param, CLIENT, buf, BUFSIZE - 10, '\n', conf.timeouts[CONNECTION_S]);
@@ -260,8 +264,11 @@ void * ftpprchild(struct clientparam* param) {
 		}
 		sc = param->remsock;
 		param->remsock = ss;
+#ifndef _WIN32
+		/* not on Windows, see the accepting side in proxymain.c */
 		param->srv->so._setsockopt(param->sostate, param->remsock, SOL_SOCKET, SO_LINGER, (char *)&lg, sizeof(lg));
 		param->srv->so._setsockopt(param->sostate, clidatasock, SOL_SOCKET, SO_LINGER, (char *)&lg, sizeof(lg));
+#endif
 		param->clisock = clidatasock;
 		res = mapsocket(param, conf.timeouts[CONNECTION_S]);
 		if(param->remsock != INVALID_SOCKET) {

src/proxymain.c

@@ -306,7 +306,9 @@ int MODULEMAINFUNC (int argc, char** argv){
  unsigned char *cbc_string = NULL, *cbl_string = NULL;
  PROXYSOCKADDRTYPE cbsa;
  FILE *fp = NULL;
+#ifndef _WIN32
  struct linger lg;
+#endif
  int nlog = 5000;
 #ifdef __linux__
  int saved_nsfd = -1;
@@ -1093,10 +1095,14 @@ int MODULEMAINFUNC (int argc, char** argv){
 #else
 		fcntl(new_sock,F_SETFL,O_NONBLOCK | fcntl(new_sock,F_GETFL));
 #endif
+#ifndef _WIN32
+		/* Not on Windows: there closesocket() on a non-blocking socket with a linger
+		   timeout fails with WSAEWOULDBLOCK while data is queued, leaving the socket
+		   open. Without it the close completes in the background, data first. */
 		lg.l_onoff = 1;
 		lg.l_linger = conf.timeouts[STRING_L];
-
 		srv.so._setsockopt(srv.so.state, new_sock, SOL_SOCKET, SO_LINGER, (char *)&lg, sizeof(lg));
+#endif
 		srv.so._setsockopt(srv.so.state, new_sock, SOL_SOCKET, SO_OOBINLINE, (char *)&opt, sizeof(int));
 	}
 #ifndef NOUDPMAIN
@@ -1382,21 +1388,34 @@ void freeparam(struct clientparam * param) {
 	}
 	if(param->clibuf) free(param->clibuf);
 	if(param->srvbuf) free(param->srvbuf);
+	/* Not shut down on Windows: there shutting down receiving resets the
+	   connection as soon as the peer sends anything more, and close()
+	   alone sends whatever is queued before its FIN. Elsewhere it stays:
+	   on the BSDs it discards what is left unread, so the close that
+	   follows is not turned into a reset. */
 	if(param->srv) {
 		if(param->ctrlsocksrv != INVALID_SOCKET && param->ctrlsocksrv != param->remsock) {
+#ifndef _WIN32
 			param->srv->so._shutdown(param->sostate, param->ctrlsocksrv, SHUT_RDWR);
+#endif
 			param->srv->so._closesocket(param->sostate, param->ctrlsocksrv);
 		}
 		if(param->ctrlsock != INVALID_SOCKET && param->ctrlsock != param->clisock) {
+#ifndef _WIN32
 			param->srv->so._shutdown(param->sostate, param->ctrlsock, SHUT_RDWR);
+#endif
 			param->srv->so._closesocket(param->sostate, param->ctrlsock);
 		}
 		if(param->remsock != INVALID_SOCKET) {
+#ifndef _WIN32
 			param->srv->so._shutdown(param->sostate, param->remsock, SHUT_RDWR);
+#endif
 			param->srv->so._closesocket(param->sostate, param->remsock);
 		}
 		if(param->clisock != INVALID_SOCKET) {
+#ifndef _WIN32
 			param->srv->so._shutdown(param->sostate, param->clisock, SHUT_RDWR);
+#endif
 			param->srv->so._closesocket(param->sostate, param->clisock);
 		}
 	}

src/sockmap.c

@@ -868,9 +868,6 @@ log("timeout");
  else if(inclientpipe || inserverpipe) res = 94;
 #endif
 
- if((param->nwrites > 0 && !SERVERTERMWRITE) || (param->nreads > 0 && !CLIENTTERMWRITE))
-	usleep(SLEEPTIME * 10);
-
 CLEANRET:
 
 #ifdef WITHSPLICE