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proto_control0.c (866B)

      1 /* Copyright (c) 2001 Matej Pfajfar.
      2 * Copyright (c) 2001-2004, Roger Dingledine.
      3 * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
      4 * Copyright (c) 2007-2021, The Tor Project, Inc. */
      5 /* See LICENSE for licensing information */
      6 
      7 /**
      8 * @file proto_control0.c
      9 * @brief Code to detect the obsolete v0 control protocol.
     10 **/
     11 
     12 #include "core/or/or.h"
     13 #include "lib/buf/buffers.h"
     14 #include "core/proto/proto_control0.h"
     15 
     16 /** Return 1 iff buf looks more like it has an (obsolete) v0 controller
     17 * command on it than any valid v1 controller command. */
     18 int
     19 peek_buf_has_control0_command(buf_t *buf)
     20 {
     21  if (buf_datalen(buf) >= 4) {
     22    char header[4];
     23    uint16_t cmd;
     24    buf_peek(buf, header, sizeof(header));
     25    cmd = ntohs(get_uint16(header+2));
     26    if (cmd <= 0x14)
     27      return 1; /* This is definitely not a v1 control command. */
     28  }
     29  return 0;
     30 }