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 /* \summary: version-independent OpenFlow printer */
  34
  35 #ifdef HAVE_CONFIG_H
  36 #include <config.h>
  37 #endif
  38
  39 #include "netdissect-stdinc.h"
  40
  41 #define ND_LONGJMP_FROM_TCHECK
  42 #include "netdissect.h"
  43 #include "extract.h"
  44 #include "openflow.h"
  45 #include "oui.h"
  46
  47
  48 #define OF_VER_1_0    0x01
  49
  50 const struct tok onf_exp_str[] = {
  51         { ONF_EXP_ONF,               "ONF Extensions"                                  },
  52         { ONF_EXP_BUTE,              "Budapest University of Technology and Economics" },
  53         { ONF_EXP_NOVIFLOW,          "NoviFlow"                                        },
  54         { ONF_EXP_L3,                "L3+ Extensions, Vendor Neutral"                  },
  55         { ONF_EXP_L4L7,              "L4-L7 Extensions"                                },
  56         { ONF_EXP_WMOB,              "Wireless and Mobility Extensions"                },
  57         { ONF_EXP_FABS,              "Forwarding Abstractions Extensions"              },
  58         { ONF_EXP_OTRANS,            "Optical Transport Extensions"                    },
  59         { 0, NULL }
  60 };
  61
  62 const char *
  63 of_vendor_name(const uint32_t vendor)
  64 {
  65         const struct tok *table = (vendor & 0xff000000) == 0 ? oui_values : onf_exp_str;
  66         return tok2str(table, "unknown", vendor);
  67 }
  68
  69 static void
  70 of_header_print(netdissect_options *ndo, const uint8_t version, const uint8_t type,
  71                       const uint16_t length, const uint32_t xid)
  72 {
  73         ND_PRINT("\n\tversion unknown (0x%02x), type 0x%02x, length %u, xid 0x%08x",
  74                version, type, length, xid);
  75 }
  76
  77 /* Print a TCP segment worth of OpenFlow messages presuming the segment begins
  78  * on a message boundary. */
  79 void
  80 openflow_print(netdissect_options *ndo, const u_char *cp, u_int len)
  81 {
  82         ndo->ndo_protocol = "openflow";
  83         ND_PRINT(": OpenFlow");
  84         while (len) {
  85                 /* Print a single OpenFlow message. */
  86                 uint8_t version, type;
  87                 uint16_t length;
  88                 uint32_t xid;
  89
  90                 if (len < OF_HEADER_FIXLEN)
  91                         goto invalid;
  92                 /* version */
  93                 version = GET_U_1(cp);
  94                 OF_FWD(1);
  95                 /* type */
  96                 type = GET_U_1(cp);
  97                 OF_FWD(1);
  98                 /* length */
  99                 length = GET_BE_U_2(cp);
 100                 OF_FWD(2);
 101                 /* xid */
 102                 xid = GET_BE_U_4(cp);
 103                 OF_FWD(4);
 104                 /*
 105                  * When a TCP packet can contain several protocol messages,
 106                  * and at the same time a protocol message can span several
 107                  * TCP packets, decoding an incomplete message at the end of
 108                  * a TCP packet requires attention to detail in this loop.
 109                  *
 110                  * Message length includes the header length and a message
 111                  * always includes the basic header. A message length underrun
 112                  * fails decoding of the rest of the current packet. At the
 113                  * same time, try decoding as much of the current message as
 114                  * possible even when it does not end within the current TCP
 115                  * segment.
 116                  *
 117                  * Specifically, to try to process the message body in this
 118                  * iteration do NOT require the header "length" to be small
 119                  * enough for the full declared OpenFlow message to fit into
 120                  * the remainder of the declared TCP segment, same as the full
 121                  * declared TCP segment is not required to fit into the
 122                  * captured packet buffer.
 123                  *
 124                  * But DO require the same at the end of this iteration to
 125                  * decrement "len" and to proceed to the next iteration.
 126                  * (Ideally the declared TCP payload end will be at or after
 127                  * the captured packet buffer end, but stay safe even when
 128                  * that's somehow not the case.)
 129                  */
 130                 if (length < OF_HEADER_FIXLEN) {
 131                         of_header_print(ndo, version, type, length, xid);
 132                         goto invalid;
 133                 }
 134                 /*
 135                  * Decode known protocol versions further without printing the
 136                  * header (the type decoding is version-specific).
 137                  */
 138                 switch (version) {
 139                 case OF_VER_1_0:
 140                         of10_header_body_print(ndo, cp, type,
 141                                                length - OF_HEADER_FIXLEN, xid);
 142                         break;
 143                 default:
 144                         of_header_print(ndo, version, type, length, xid);
 145                         ND_TCHECK_LEN(cp, length - OF_HEADER_FIXLEN);
 146                 }
 147                 if (length - OF_HEADER_FIXLEN > len)
 148                         break;
 149                 OF_FWD(length - OF_HEADER_FIXLEN);
 150         } /* while (len) */
 151         return;
 152
 153 invalid: /* fail the current packet */
 154         nd_print_invalid(ndo);
 155         ND_TCHECK_LEN(cp, len);
 156 }