Commit 62b6948a authored by Dr. Stephen Henson's avatar Dr. Stephen Henson
Browse files

PR: 2755 

Submitted by: Robin Seggelmann <seggelmann@fh-muenster.de>

Reduce MTU after failed transmissions.
parent 0fbf8b9c

crypto/bio/bio.h

+1 −0
Original line number Diff line number Diff line
@@ -157,6 +157,7 @@ extern "C" { 
/* #endif */



#define BIO_CTRL_DGRAM_QUERY_MTU          40 /* as kernel for current MTU */

#define BIO_CTRL_DGRAM_GET_FALLBACK_MTU   47

#define BIO_CTRL_DGRAM_GET_MTU            41 /* get cached value for MTU */

#define BIO_CTRL_DGRAM_SET_MTU            42 /* set cached value for

					      * MTU. want to use this

crypto/bio/bss_dgram.c

+21 −0
Original line number Diff line number Diff line
@@ -616,6 +616,27 @@ static long dgram_ctrl(BIO *b, int cmd, long num, void *ptr) 
		ret = 0;

#endif

		break;

	case BIO_CTRL_DGRAM_GET_FALLBACK_MTU:

		switch (data->peer.sa.sa_family)

			{

			case AF_INET:

				ret = 576 - 20 - 8;

				break;

#if OPENSSL_USE_IPV6

			case AF_INET6:

#ifdef IN6_IS_ADDR_V4MAPPED

				if (IN6_IS_ADDR_V4MAPPED(&data->peer.sa_in6.sin6_addr))

					ret = 576 - 20 - 8;

				else

#endif

					ret = 1280 - 40 - 8;

				break;

#endif

			default:

				ret = 576 - 20 - 8;

				break;

			}

		break;

	case BIO_CTRL_DGRAM_GET_MTU:

		return data->mtu;

		break;

ssl/d1_both.c

+2 −2
Original line number Diff line number Diff line
@@ -227,7 +227,7 @@ int dtls1_do_write(SSL *s, int type) 
	unsigned int len, frag_off, mac_size, blocksize;



	/* AHA!  Figure out the MTU, and stick to the right size */

	if ( ! (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))

	if (s->d1->mtu < dtls1_min_mtu() && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))

		{

		s->d1->mtu = 

			BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);

ssl/d1_lib.c

+5 −0
Original line number Diff line number Diff line
@@ -424,6 +424,11 @@ int dtls1_handle_timeout(SSL *s) 
		state->timeout.read_timeouts = 1;

		}



	if (state->timeout_duration > 2)

		{

		s->d1->mtu = BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL);		

		}



#ifndef OPENSSL_NO_HEARTBEATS

	if (s->tlsext_hb_pending)

		{