Updates to s_client and s_server to remove the constant 28 (for IPv4 header
and UDP header) when setting an mtu. This constant is not always correct (e.g.
if using IPv6). Use the new DTLS_CTRL functions instead.
Reviewed-by: Tim Hudson <tjh@openssl.org>
diff --git a/apps/s_client.c b/apps/s_client.c
index e4281c6..cde7713 100644
--- a/apps/s_client.c
+++ b/apps/s_client.c
@@ -1529,10 +1529,22 @@
BIO_ctrl(sbio, BIO_CTRL_DGRAM_SET_SEND_TIMEOUT, 0, &timeout);
}
- if (socket_mtu > 28)
+ if (socket_mtu)
{
+ if(socket_mtu < DTLS_get_link_min_mtu(con))
+ {
+ BIO_printf(bio_err,"MTU too small. Must be at least %ld\n",
+ DTLS_get_link_min_mtu(con));
+ BIO_free(sbio);
+ goto shut;
+ }
SSL_set_options(con, SSL_OP_NO_QUERY_MTU);
- SSL_set_mtu(con, socket_mtu - 28);
+ if(!DTLS_set_link_mtu(con, socket_mtu))
+ {
+ BIO_printf(bio_err, "Failed to set MTU\n");
+ BIO_free(sbio);
+ goto shut;
+ }
}
else
/* want to do MTU discovery */
