Implement Maximum Fragment Length TLS extension.

Based on patch from Tomasz Moń:
https://groups.google.com/forum/#!topic/mailing.openssl.dev/fQxXvCg1uQY

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
(Merged from https://github.com/openssl/openssl/pull/1008)

1 files changed, 31 insertions, 0 deletions

diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index 28b25e122f..48f01ffe9d 100644
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -2406,3 +2406,34 @@ int tls_choose_sigalg(SSL *s, int *al)
     s->s3->tmp.sigalg = lu;
     return 1;
 }
+
+int SSL_CTX_set_tlsext_max_fragment_length(SSL_CTX *ctx, uint8_t mode)
+{
+    if (mode != TLSEXT_max_fragment_length_DISABLED
+            && !IS_MAX_FRAGMENT_LENGTH_EXT_VALID(mode)) {
+        SSLerr(SSL_F_SSL_CTX_SET_TLSEXT_MAX_FRAGMENT_LENGTH,
+               SSL_R_SSL3_EXT_INVALID_MAX_FRAGMENT_LENGTH);
+        return 0;
+    }
+
+    ctx->ext.max_fragment_len_mode = mode;
+    return 1;
+}
+
+int SSL_set_tlsext_max_fragment_length(SSL *ssl, uint8_t mode)
+{
+    if (mode != TLSEXT_max_fragment_length_DISABLED
+            && !IS_MAX_FRAGMENT_LENGTH_EXT_VALID(mode)) {
+        SSLerr(SSL_F_SSL_SET_TLSEXT_MAX_FRAGMENT_LENGTH,
+               SSL_R_SSL3_EXT_INVALID_MAX_FRAGMENT_LENGTH);
+        return 0;
+    }
+
+    ssl->ext.max_fragment_len_mode = mode;
+    return 1;
+}
+
+uint8_t SSL_SESSION_get_max_fragment_length(const SSL_SESSION *session)
+{
+    return session->ext.max_fragment_len_mode;
+}