From 914c5dad0cd846870efd5e6b10faf5d0bbb9febe Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Mon, 15 May 2017 08:10:43 -0600
Subject: [PATCH] TCP: An RST recevied suring the 3-way handshake requires a
 little more clean-up

---
 net/tcp/tcp_input.c | 40 +++++++++++++++++++++++++++++++++++++---
 net/tcp/tcp_timer.c |  2 +-
 2 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/net/tcp/tcp_input.c b/net/tcp/tcp_input.c
index 23bec6a6e55..d1addb0bbf0 100644
--- a/net/tcp/tcp_input.c
+++ b/net/tcp/tcp_input.c
@@ -314,10 +314,44 @@ found:
 
   if ((tcp->flags & TCP_RST) != 0)
     {
-      conn->tcpstateflags = TCP_CLOSED;
-      nwarn("WARNING: RESET - TCP state: TCP_CLOSED\n");
+      FAR struct tcp_conn_s *listener = NULL;
+
+      /* An RST received during the 3-way connection handshake requires
+       * little more clean-up.
+       */
+
+      if ((conn->tcpstateflags & TCP_STATE_MASK) == TCP_SYN_RCVD)
+        {
+          conn->tcpstateflags = TCP_CLOSED;
+          nwarn("WARNING: RESET in TCP_SYN_RCVD\n");
+
+          /* Notify the listerner for connection of the reset event */
+
+          listener = tcp_findlistener(conn->lport);
+
+          /* We must free this TCP connection structure, this connection
+           * will never be established.
+           */
+
+          tcp_free(conn);
+        }
+      else
+        {
+          conn->tcpstateflags = TCP_CLOSED;
+          nwarn("WARNING: RESET TCP state: TCP_CLOSED\n");
+
+          /* Notify this connection of the reset event */
+
+          listener = conn;
+        }
+
+      /* Perform the TCP_ABORT callback and drop the packet */
+
+      if (listener != NULL)
+        {
+          (void)tcp_callback(dev, listener, TCP_ABORT);
+        }
 
-      (void)tcp_callback(dev, conn, TCP_ABORT);
       goto drop;
     }
 
diff --git a/net/tcp/tcp_timer.c b/net/tcp/tcp_timer.c
index a9047fc4785..03935c964b2 100644
--- a/net/tcp/tcp_timer.c
+++ b/net/tcp/tcp_timer.c
@@ -231,7 +231,7 @@ void tcp_timer(FAR struct net_driver_s *dev, FAR struct tcp_conn_s *conn,
                   FAR struct tcp_conn_s *listener;
 
                   conn->tcpstateflags = TCP_CLOSED;
-                  ninfo("TCP state: TCP_CLOSED\n");
+                  ninfo("TCP state: TCP_SYN_RCVD->TCP_CLOSED\n");
 
                   /* Find the listener for this connection. */