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 #include "openflow.h"
  42
  43 static const char tstr[] = " [|openflow]";
  44 static const char cstr[] = " (corrupt)";
  45
  46 #define OF_VER_1_0    0x01
  47
  48 static void
  49 of_header_print(const uint8_t version, const uint8_t type,
  50                       const uint16_t length, const uint32_t xid) {
  51         printf("\n\tversion unknown (0x%02x), type 0x%02x, length %u, xid 0x%08x",
  52                version, type, length, xid);
  53 }
  54
  55 /* Print a single OpenFlow message. */
  56 static const u_char *
  57 of_header_body_print(const u_char *cp, const u_char *ep) {
  58         uint8_t version, type;
  59         uint16_t length;
  60         uint32_t xid;
  61
  62         if (ep < cp + OF_HEADER_LEN)
  63                 goto corrupt;
  64         /* version */
  65         TCHECK2(*cp, 1);
  66         version = *cp;
  67         cp += 1;
  68         /* type */
  69         TCHECK2(*cp, 1);
  70         type = *cp;
  71         cp += 1;
  72         /* length */
  73         TCHECK2(*cp, 2);
  74         length = EXTRACT_16BITS(cp);
  75         cp += 2;
  76         /* xid */
  77         TCHECK2(*cp, 4);
  78         xid = EXTRACT_32BITS(cp);
  79         cp += 4;
  80         /* Message length includes the header length and a message always includes
  81          * the basic header. A message length underrun fails decoding of the rest of
  82          * the current packet. At the same time, try decoding as much of the current
  83          * message as possible even when it does not end within the current TCP
  84          * segment. */
  85         if (length < OF_HEADER_LEN) {
  86                 of_header_print(version, type, length, xid);
  87                 goto corrupt;
  88         }
  89         /* Decode known protocol versions further without printing the header (the
  90          * type decoding is version-specific. */
  91         switch (version) {
  92         case OF_VER_1_0:
  93                 return of10_header_body_print(cp, ep, type, length, xid);
  94         default:
  95                 of_header_print(version, type, length, xid);
  96                 TCHECK2(*cp, length - OF_HEADER_LEN);
  97                 return cp + length - OF_HEADER_LEN; /* done with current message */
  98         }
  99
 100 corrupt: /* fail current packet */
 101         printf("%s", cstr);
 102         TCHECK2(*cp, ep - cp);
 103         return ep;
 104 trunc:
 105         printf("%s", tstr);
 106         return ep;
 107 }
 108
 109 /* Print a TCP segment worth of OpenFlow messages presuming the segment begins
 110  * on a message boundary. */
 111 void
 112 openflow_print(const u_char *cp, const u_int len) {
 113         const u_char *ep = cp + len;
 114
 115         printf(": OpenFlow");
 116         while (cp < ep)
 117                 cp = of_header_body_print(cp, ep);
 118 }