From 50161075506aedcc57fc7b058d89fefc72481374 Mon Sep 17 00:00:00 2001
From: "Dr. Stephen Henson" <steve@openssl.org>
Date: Fri, 9 Mar 2012 15:51:56 +0000
Subject: [PATCH] PR: 2756 Submitted by: Robin Seggelmann
 <seggelmann@fh-muenster.de>

Fix DTLS timeout handling.
---
 ssl/d1_lib.c   | 38 ++++++++++++++++++++++++++------------
 ssl/d1_pkt.c   | 12 +++---------
 ssl/ssl_locl.h |  1 +
 3 files changed, 30 insertions(+), 21 deletions(-)

diff --git a/ssl/d1_lib.c b/ssl/d1_lib.c
index bceba3c971..8155a890bd 100644
--- a/ssl/d1_lib.c
+++ b/ssl/d1_lib.c
@@ -421,6 +421,7 @@ void dtls1_double_timeout(SSL *s)
 void dtls1_stop_timer(SSL *s)
 	{
 	/* Reset everything */
+	memset(&(s->d1->timeout), 0, sizeof(struct dtls1_timeout_st));
 	memset(&(s->d1->next_timeout), 0, sizeof(struct timeval));
 	s->d1->timeout_duration = 1;
 	BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, &(s->d1->next_timeout));
@@ -428,30 +429,43 @@ void dtls1_stop_timer(SSL *s)
 	dtls1_clear_record_buffer(s);
 	}
 
-int dtls1_handle_timeout(SSL *s)
+int dtls1_check_timeout_num(SSL *s)
 	{
-	DTLS1_STATE *state;
+	s->d1->timeout.num_alerts++;
 
-	/* if no timer is expired, don't do anything */
-	if (!dtls1_is_timer_expired(s))
+	/* Reduce MTU after 2 unsuccessful retransmissions */
+	if (s->d1->timeout.num_alerts > 2)
 		{
-		return 0;
+		s->d1->mtu = BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL);		
 		}
 
-	dtls1_double_timeout(s);
-	state = s->d1;
-	state->timeout.num_alerts++;
-	if ( state->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT)
+	if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT)
 		{
 		/* fail the connection, enough alerts have been sent */
 		SSLerr(SSL_F_DTLS1_HANDLE_TIMEOUT,SSL_R_READ_TIMEOUT_EXPIRED);
 		return -1;
 		}
 
-	state->timeout.read_timeouts++;
-	if ( state->timeout.read_timeouts > DTLS1_TMO_READ_COUNT)
+	return 0;
+	}
+
+int dtls1_handle_timeout(SSL *s)
+	{
+	/* if no timer is expired, don't do anything */
+	if (!dtls1_is_timer_expired(s))
+		{
+		return 0;
+		}
+
+	dtls1_double_timeout(s);
+
+	if (dtls1_check_timeout_num(s) < 0)
+		return -1;
+
+	s->d1->timeout.read_timeouts++;
+	if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT)
 		{
-		state->timeout.read_timeouts = 1;
+		s->d1->timeout.read_timeouts = 1;
 		}
 
 	if (state->timeout_duration > 2)
diff --git a/ssl/d1_pkt.c b/ssl/d1_pkt.c
index b709ebbfaa..65b1ef28cd 100644
--- a/ssl/d1_pkt.c
+++ b/ssl/d1_pkt.c
@@ -139,7 +139,6 @@ static int dtls1_process_record(SSL *s);
 #if PQ_64BIT_IS_INTEGER
 static PQ_64BIT bytes_to_long_long(unsigned char *bytes, PQ_64BIT *num);
 #endif
-static void dtls1_clear_timeouts(SSL *s);
 
 /* copy buffered record into SSL structure */
 static int
@@ -640,7 +639,6 @@ again:
 		goto again;     /* get another record */
 		}
 
-	dtls1_clear_timeouts(s);  /* done waiting */
 	return(1);
 
 	}
@@ -1109,6 +1107,9 @@ start:
 		 */
 		if (msg_hdr.type == SSL3_MT_FINISHED)
 			{
+			if (dtls1_check_timeout_num(s) < 0)
+				return -1;
+
 			dtls1_retransmit_buffered_messages(s);
 			rr->length = 0;
 			goto start;
@@ -1812,10 +1813,3 @@ bytes_to_long_long(unsigned char *bytes, PQ_64BIT *num)
        return _num;
        }
 #endif
-
-
-static void
-dtls1_clear_timeouts(SSL *s)
-	{
-	memset(&(s->d1->timeout), 0x00, sizeof(struct dtls1_timeout_st));
-	}
diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h
index 4741e30b2b..3d581f1f2f 100644
--- a/ssl/ssl_locl.h
+++ b/ssl/ssl_locl.h
@@ -870,6 +870,7 @@ void dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st *ccs_hdr);
 void dtls1_reset_seq_numbers(SSL *s, int rw);
 long dtls1_default_timeout(void);
 struct timeval* dtls1_get_timeout(SSL *s, struct timeval* timeleft);
+int dtls1_check_timeout_num(SSL *s);
 int dtls1_handle_timeout(SSL *s);
 SSL_CIPHER *dtls1_get_cipher(unsigned int u);
 void dtls1_start_timer(SSL *s);
-- 
2.25.1