don't fail closing a socket/netconn when failing to allocate the FIN segment; blocking the calling thread for a while is better than risking leaking a netconn/socket (see bug #46701)

Signed-off-by: sg <goldsimon@gmx.de>

CHANGELOG

@@ -18,7 +18,7 @@ HISTORY
 
   2015-11-12: Dirk Ziegelmeier
   * Implement possibility to declare private memory pools. This is useful to
-    decouple some apps from the core (SNMP stack) or make contrib app useage
+    decouple some apps from the core (SNMP stack) or make contrib app usage
     simpler (httpserver_raw)
 
   2015-10-09: Simon Goldschmidt
@@ -302,6 +302,11 @@ HISTORY
 
   ++ Bugfixes:
 
+  2013-03-17: Joel Cunningham
+  * api_msg.c: don't fail closing a socket/netconn when failing to allocate the
+    FIN segment; blocking the calling thread for a while is better than risking
+    leaking a netconn/socket (see bug #46701)
+
   2013-03-16: Joel Cunningham
   * tcp_out.c: reset rto timer on fast retransmission
 

src/api/api_msg.c

@@ -884,38 +884,33 @@ lwip_netconn_do_close_internal(struct netconn *conn  WRITE_DELAYED_PARAM)
 #endif /* LWIP_SO_LINGER */
   } else {
     if (err == ERR_MEM) {
-      /* Closing failed because of memory shortage */
-      if (netconn_is_nonblocking(conn)) {
-        /* Nonblocking close failed */
-        close_finished = 1;
-        err = ERR_WOULDBLOCK;
-      } else {
-        /* Blocking close, check the timeout */
+      /* Closing failed because of memory shortage, try again later. Even for
+         nonblocking netconns, we have to wait since no standard socket application
+         is prepared for close failing because of resource shortage.
+         Check the timeout: this is kind of an lwip addition to the standard sockets:
+         we wait for some time when failing to allocate a segment for the FIN */
 #if LWIP_SO_SNDTIMEO || LWIP_SO_LINGER
-        s32_t close_timeout = LWIP_TCP_CLOSE_TIMEOUT_MS_DEFAULT;
-        /* this is kind of an lwip addition to the standard sockets: we wait
-           for some time when failing to allocate a segment for the FIN */
+      s32_t close_timeout = LWIP_TCP_CLOSE_TIMEOUT_MS_DEFAULT;
 #if LWIP_SO_SNDTIMEO
-        if (conn->send_timeout > 0) {
-          close_timeout = conn->send_timeout;
-        }
+      if (conn->send_timeout > 0) {
+        close_timeout = conn->send_timeout;
+      }
 #endif /* LWIP_SO_SNDTIMEO */
 #if LWIP_SO_LINGER
-        if (conn->linger >= 0) {
-          /* use linger timeout (seconds) */
-          close_timeout = conn->linger * 1000U;
-        }
+      if (conn->linger >= 0) {
+        /* use linger timeout (seconds) */
+        close_timeout = conn->linger * 1000U;
+      }
 #endif
-        if ((s32_t)(sys_now() - conn->current_msg->msg.sd.time_started) >= close_timeout) {
+      if ((s32_t)(sys_now() - conn->current_msg->msg.sd.time_started) >= close_timeout) {
 #else /* LWIP_SO_SNDTIMEO || LWIP_SO_LINGER */
-        if (conn->current_msg->msg.sd.polls_left == 0) {
+      if (conn->current_msg->msg.sd.polls_left == 0) {
 #endif /* LWIP_SO_SNDTIMEO || LWIP_SO_LINGER */
-          close_finished = 1;
-          if (close) {
-            /* in this case, we want to RST the connection */
-            tcp_abort(tpcb);
-            err = ERR_OK;
-          }
+        close_finished = 1;
+        if (close) {
+          /* in this case, we want to RST the connection */
+          tcp_abort(tpcb);
+          err = ERR_OK;
         }
       }
     } else {