Move session save/load function to ssl_tls.c

This finishes making these functions public. Next step is to get them tested,
but there's currently a blocker for that, see next commit (and the commit
after it for tests).
diff --git a/library/ssl_ticket.c b/library/ssl_ticket.c
index 8492c19..5fe693c 100644
--- a/library/ssl_ticket.c
+++ b/library/ssl_ticket.c
@@ -157,115 +157,6 @@
 }
 
 /*
- * Serialize a session in the following format:
- *  0   .   n-1     session structure, n = sizeof(mbedtls_ssl_session)
- *  n   .   n+2     peer_cert length = m (0 if no certificate)
- *  n+3 .   n+2+m   peer cert ASN.1
- */
-static int ssl_save_session( const mbedtls_ssl_session *session,
-                             unsigned char *buf, size_t buf_len,
-                             size_t *olen )
-{
-    unsigned char *p = buf;
-    size_t left = buf_len;
-#if defined(MBEDTLS_X509_CRT_PARSE_C)
-    size_t cert_len;
-#endif /* MBEDTLS_X509_CRT_PARSE_C */
-
-    if( left < sizeof( mbedtls_ssl_session ) )
-        return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
-
-    memcpy( p, session, sizeof( mbedtls_ssl_session ) );
-    p += sizeof( mbedtls_ssl_session );
-    left -= sizeof( mbedtls_ssl_session );
-
-#if defined(MBEDTLS_X509_CRT_PARSE_C)
-    if( session->peer_cert == NULL )
-        cert_len = 0;
-    else
-        cert_len = session->peer_cert->raw.len;
-
-    if( left < 3 + cert_len )
-        return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
-
-    *p++ = (unsigned char)( ( cert_len >> 16 ) & 0xFF );
-    *p++ = (unsigned char)( ( cert_len >>  8 ) & 0xFF );
-    *p++ = (unsigned char)( ( cert_len       ) & 0xFF );
-
-    if( session->peer_cert != NULL )
-        memcpy( p, session->peer_cert->raw.p, cert_len );
-
-    p += cert_len;
-#endif /* MBEDTLS_X509_CRT_PARSE_C */
-
-    *olen = p - buf;
-
-    return( 0 );
-}
-
-/*
- * Unserialise session, see ssl_save_session()
- */
-static int ssl_load_session( mbedtls_ssl_session *session,
-                             const unsigned char *buf, size_t len )
-{
-    const unsigned char *p = buf;
-    const unsigned char * const end = buf + len;
-#if defined(MBEDTLS_X509_CRT_PARSE_C)
-    size_t cert_len;
-#endif /* MBEDTLS_X509_CRT_PARSE_C */
-
-    if( sizeof( mbedtls_ssl_session ) > (size_t)( end - p ) )
-        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
-
-    memcpy( session, p, sizeof( mbedtls_ssl_session ) );
-    p += sizeof( mbedtls_ssl_session );
-
-#if defined(MBEDTLS_X509_CRT_PARSE_C)
-    if( 3 > (size_t)( end - p ) )
-        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
-
-    cert_len = ( p[0] << 16 ) | ( p[1] << 8 ) | p[2];
-    p += 3;
-
-    if( cert_len == 0 )
-    {
-        session->peer_cert = NULL;
-    }
-    else
-    {
-        int ret;
-
-        if( cert_len > (size_t)( end - p ) )
-            return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
-
-        session->peer_cert = mbedtls_calloc( 1, sizeof( mbedtls_x509_crt ) );
-
-        if( session->peer_cert == NULL )
-            return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
-
-        mbedtls_x509_crt_init( session->peer_cert );
-
-        if( ( ret = mbedtls_x509_crt_parse_der( session->peer_cert,
-                                                p, cert_len ) ) != 0 )
-        {
-            mbedtls_x509_crt_free( session->peer_cert );
-            mbedtls_free( session->peer_cert );
-            session->peer_cert = NULL;
-            return( ret );
-        }
-
-        p += cert_len;
-    }
-#endif /* MBEDTLS_X509_CRT_PARSE_C */
-
-    if( p != end )
-        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
-
-    return( 0 );
-}
-
-/*
  * Create session ticket, with the following structure:
  *
  *    struct {
@@ -323,8 +214,9 @@
         goto cleanup;
 
     /* Dump session state */
-    if( ( ret = ssl_save_session( session,
-                                  state, end - state, &clear_len ) ) != 0 ||
+    if( ( ret = mbedtls_ssl_session_save( session,
+                                          state, end - state,
+                                          &clear_len ) ) != 0 ||
         (unsigned long) clear_len > 65535 )
     {
          goto cleanup;
@@ -441,7 +333,7 @@
     }
 
     /* Actually load session */
-    if( ( ret = ssl_load_session( session, ticket, clear_len ) ) != 0 )
+    if( ( ret = mbedtls_ssl_session_load( session, ticket, clear_len ) ) != 0 )
         goto cleanup;
 
 #if defined(MBEDTLS_HAVE_TIME)
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 81bed84..9c1a39f 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -8768,6 +8768,117 @@
 #endif /* MBEDTLS_SSL_CLI_C */
 
 /*
+ * Serialize a session in the following format:
+ *  0   .   n-1     session structure, n = sizeof(mbedtls_ssl_session)
+ *  n   .   n+2     peer_cert length = m (0 if no certificate)
+ *  n+3 .   n+2+m   peer cert ASN.1
+ */
+int mbedtls_ssl_session_save( const mbedtls_ssl_session *session,
+                              unsigned char *buf,
+                              size_t buf_len,
+                              size_t *olen )
+{
+    unsigned char *p = buf;
+    size_t left = buf_len;
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+    size_t cert_len;
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+
+    if( left < sizeof( mbedtls_ssl_session ) )
+        return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
+
+    memcpy( p, session, sizeof( mbedtls_ssl_session ) );
+    p += sizeof( mbedtls_ssl_session );
+    left -= sizeof( mbedtls_ssl_session );
+
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+    if( session->peer_cert == NULL )
+        cert_len = 0;
+    else
+        cert_len = session->peer_cert->raw.len;
+
+    if( left < 3 + cert_len )
+        return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
+
+    *p++ = (unsigned char)( ( cert_len >> 16 ) & 0xFF );
+    *p++ = (unsigned char)( ( cert_len >>  8 ) & 0xFF );
+    *p++ = (unsigned char)( ( cert_len       ) & 0xFF );
+
+    if( session->peer_cert != NULL )
+        memcpy( p, session->peer_cert->raw.p, cert_len );
+
+    p += cert_len;
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+
+    *olen = p - buf;
+
+    return( 0 );
+}
+
+/*
+ * Unserialise session, see mbedtls_ssl_session_save()
+ */
+int mbedtls_ssl_session_load( mbedtls_ssl_session *session,
+                              const unsigned char *buf,
+                              size_t len )
+{
+    const unsigned char *p = buf;
+    const unsigned char * const end = buf + len;
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+    size_t cert_len;
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+
+    if( sizeof( mbedtls_ssl_session ) > (size_t)( end - p ) )
+        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+
+    memcpy( session, p, sizeof( mbedtls_ssl_session ) );
+    p += sizeof( mbedtls_ssl_session );
+
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+    if( 3 > (size_t)( end - p ) )
+        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+
+    cert_len = ( p[0] << 16 ) | ( p[1] << 8 ) | p[2];
+    p += 3;
+
+    if( cert_len == 0 )
+    {
+        session->peer_cert = NULL;
+    }
+    else
+    {
+        int ret;
+
+        if( cert_len > (size_t)( end - p ) )
+            return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+
+        session->peer_cert = mbedtls_calloc( 1, sizeof( mbedtls_x509_crt ) );
+
+        if( session->peer_cert == NULL )
+            return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
+
+        mbedtls_x509_crt_init( session->peer_cert );
+
+        if( ( ret = mbedtls_x509_crt_parse_der( session->peer_cert,
+                                                p, cert_len ) ) != 0 )
+        {
+            mbedtls_x509_crt_free( session->peer_cert );
+            mbedtls_free( session->peer_cert );
+            session->peer_cert = NULL;
+            return( ret );
+        }
+
+        p += cert_len;
+    }
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+
+    if( p != end )
+        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+
+    return( 0 );
+}
+
+/*
  * Perform a single step of the SSL handshake
  */
 int mbedtls_ssl_handshake_step( mbedtls_ssl_context *ssl )