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 #define NETDISSECT_REWORKED
  34 #ifdef HAVE_CONFIG_H
  35 #include "config.h"
  36 #endif
  37
  38 #include <tcpdump-stdinc.h>
  39
  40 #include "interface.h"
  41 #include "extract.h"
  42 #include "openflow.h"
  43
  44 static const char tstr[] = " [|openflow]";
  45 static const char cstr[] = " (corrupt)";
  46
  47 #define OF_VER_1_0    0x01
  48
  49 static void
  50 of_header_print(netdissect_options *ndo, const uint8_t version, const uint8_t type,
  51                       const uint16_t length, const uint32_t xid) {
  52         ND_PRINT((ndo, "\n\tversion unknown (0x%02x), type 0x%02x, length %u, xid 0x%08x",
  53                version, type, length, xid));
  54 }
  55
  56 /* Print a single OpenFlow message. */
  57 static const u_char *
  58 of_header_body_print(netdissect_options *ndo, const u_char *cp, const u_char *ep) {
  59         uint8_t version, type;
  60         uint16_t length;
  61         uint32_t xid;
  62
  63         if (ep < cp + OF_HEADER_LEN)
  64                 goto corrupt;
  65         /* version */
  66         ND_TCHECK2(*cp, 1);
  67         version = *cp;
  68         cp += 1;
  69         /* type */
  70         ND_TCHECK2(*cp, 1);
  71         type = *cp;
  72         cp += 1;
  73         /* length */
  74         ND_TCHECK2(*cp, 2);
  75         length = EXTRACT_16BITS(cp);
  76         cp += 2;
  77         /* xid */
  78         ND_TCHECK2(*cp, 4);
  79         xid = EXTRACT_32BITS(cp);
  80         cp += 4;
  81         /* Message length includes the header length and a message always includes
  82          * the basic header. A message length underrun fails decoding of the rest of
  83          * the current packet. At the same time, try decoding as much of the current
  84          * message as possible even when it does not end within the current TCP
  85          * segment. */
  86         if (length < OF_HEADER_LEN) {
  87                 of_header_print(ndo, version, type, length, xid);
  88                 goto corrupt;
  89         }
  90         /* Decode known protocol versions further without printing the header (the
  91          * type decoding is version-specific. */
  92         switch (version) {
  93         case OF_VER_1_0:
  94                 return of10_header_body_print(ndo, cp, ep, type, length, xid);
  95         default:
  96                 of_header_print(ndo, version, type, length, xid);
  97                 ND_TCHECK2(*cp, length - OF_HEADER_LEN);
  98                 return cp + length - OF_HEADER_LEN; /* done with current message */
  99         }
 100
 101 corrupt: /* fail current packet */
 102         ND_PRINT((ndo, "%s", cstr));
 103         ND_TCHECK2(*cp, ep - cp);
 104         return ep;
 105 trunc:
 106         ND_PRINT((ndo, "%s", tstr));
 107         return ep;
 108 }
 109
 110 /* Print a TCP segment worth of OpenFlow messages presuming the segment begins
 111  * on a message boundary. */
 112 void
 113 openflow_print(netdissect_options *ndo, const u_char *cp, const u_int len) {
 114         const u_char *ep = cp + len;
 115
 116         ND_PRINT((ndo, ": OpenFlow"));
 117         while (cp < ep)
 118                 cp = of_header_body_print(ndo, cp, ep);
 119 }