The Tcpdump Group git mirrors - tcpdump/blob - print-openflow.c

   1 /*
   2  * This module implements printing of the very basic (version-independent)
   3  * OpenFlow header and iteration over OpenFlow messages. It is intended for
   4  * dispatching of version-specific OpenFlow message decoding.
   5  *
   6  *
   7  * Copyright (c) 2013 The TCPDUMP project
   8  * All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  20  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  22  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  23  * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  24  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  25  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  26  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  27  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  29  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  30  * POSSIBILITY OF SUCH DAMAGE.
  31  */
  32
  33 #ifdef HAVE_CONFIG_H
  34 #include "config.h"
  35 #endif
  36
  37 #include <tcpdump-stdinc.h>
  38
  39 #include "interface.h"
  40 #include "extract.h"
  41
  42 #define OF_HEADER_LEN 8
  43
  44 static void
  45 of_header_print(const uint8_t version, const uint8_t type,
  46                       const uint16_t length, const uint32_t xid) {
  47         printf("\n\tversion unknown (0x%02x), type 0x%02x, length %u, xid 0x%08x",
  48                version, type, length, xid);
  49 }
  50
  51 /* Print a single OpenFlow message. */
  52 static const u_char *
  53 of_header_body_print(const u_char *cp, const u_char *ep) {
  54         uint8_t version, type;
  55         uint16_t length;
  56         uint32_t xid;
  57
  58         if (ep < cp + OF_HEADER_LEN)
  59                 goto corrupt;
  60         /* version */
  61         TCHECK2(*cp, 1);
  62         version = *cp;
  63         cp += 1;
  64         /* type */
  65         TCHECK2(*cp, 1);
  66         type = *cp;
  67         cp += 1;
  68         /* length */
  69         TCHECK2(*cp, 2);
  70         length = EXTRACT_16BITS(cp);
  71         cp += 2;
  72         /* xid */
  73         TCHECK2(*cp, 4);
  74         xid = EXTRACT_32BITS(cp);
  75         cp += 4;
  76         /* Message length includes the header length and a message always includes
  77          * the basic header. A message length underrun fails decoding of the rest of
  78          * the current packet. At the same time, try decoding as much of the current
  79          * message as possible even when it does not end within the current TCP
  80          * segment. */
  81         if (length < OF_HEADER_LEN) {
  82                 of_header_print(version, type, length, xid);
  83                 goto corrupt;
  84         }
  85         /* Decode known protocol versions further without printing the header (the
  86          * type decoding is version-specific. */
  87         switch (version) {
  88         default:
  89                 of_header_print(version, type, length, xid);
  90                 TCHECK2(*cp, length - OF_HEADER_LEN);
  91                 return cp + length - OF_HEADER_LEN; /* done with current message */
  92         }
  93
  94 corrupt: /* fail current packet */
  95         printf(" (corrupt)");
  96         TCHECK2(*cp, ep - cp);
  97         return ep;
  98 trunc:
  99         printf(" [|openflow]");
 100         return ep;
 101 }
 102
 103 /* Print a TCP segment worth of OpenFlow messages presuming the segment begins
 104  * on a message boundary. */
 105 void
 106 openflow_print(const u_char *cp, const u_int len) {
 107         const u_char *ep = cp + len;
 108
 109         printf(": OpenFlow");
 110         while (cp < ep)
 111                 cp = of_header_body_print(cp, ep);
 112 }