1 files changed, 40 insertions, 0 deletions
diff --git a/src/or/proto_ext_or.c b/src/or/proto_ext_or.c
new file mode 100644
index 0000000000..057cf109ec
--- /dev/null
+++ b/src/or/proto_ext_or.c
@@ -0,0 +1,40 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2017, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "or.h"
+#include "buffers.h"
+#include "ext_orport.h"
+#include "proto_ext_or.h"
+
+/** The size of the header of an Extended ORPort message: 2 bytes for
+ *  COMMAND, 2 bytes for BODYLEN */
+#define EXT_OR_CMD_HEADER_SIZE 4
+
+/** Read <b>buf</b>, which should contain an Extended ORPort message
+ *  from a transport proxy. If well-formed, create and populate
+ *  <b>out</b> with the Extended ORport message. Return 0 if the
+ *  buffer was incomplete, 1 if it was well-formed and -1 if we
+ *  encountered an error while parsing it.  */
+int
+fetch_ext_or_command_from_buf(buf_t *buf, ext_or_cmd_t **out)
+{
+  char hdr[EXT_OR_CMD_HEADER_SIZE];
+  uint16_t len;
+
+  if (buf_datalen(buf) < EXT_OR_CMD_HEADER_SIZE)
+    return 0;
+  buf_peek(buf, hdr, sizeof(hdr));
+  len = ntohs(get_uint16(hdr+2));
+  if (buf_datalen(buf) < (unsigned)len + EXT_OR_CMD_HEADER_SIZE)
+    return 0;
+  *out = ext_or_cmd_new(len);
+  (*out)->cmd = ntohs(get_uint16(hdr));
+  (*out)->len = len;
+  buf_drain(buf, EXT_OR_CMD_HEADER_SIZE);
+  buf_get_bytes(buf, (*out)->body, len);
+  return 1;
+}
+