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136 lines
3.6 KiB
136 lines
3.6 KiB
/* |
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* Copyright (c) 2014 The TCPDUMP project |
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* All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
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* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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* POSSIBILITY OF SUCH DAMAGE. |
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*/ |
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/* \summary: Loopback Protocol printer */ |
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/* |
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* originally defined as the Ethernet Configuration Testing Protocol. |
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* specification: http://www.mit.edu/people/jhawk/ctp.pdf |
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*/ |
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#ifdef HAVE_CONFIG_H |
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#include "config.h" |
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#endif |
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#include <netdissect-stdinc.h> |
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#include "netdissect.h" |
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#include "extract.h" |
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#include "ether.h" |
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#include "addrtoname.h" |
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static const char tstr[] = " [|loopback]"; |
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#define LOOPBACK_REPLY 1 |
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#define LOOPBACK_FWDDATA 2 |
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static const struct tok fcode_str[] = { |
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{ LOOPBACK_REPLY, "Reply" }, |
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{ LOOPBACK_FWDDATA, "Forward Data" }, |
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{ 0, NULL } |
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}; |
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static void |
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loopback_message_print(netdissect_options *ndo, const u_char *cp, const u_int len) |
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{ |
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const u_char *ep = cp + len; |
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uint16_t function; |
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if (len < 2) |
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goto invalid; |
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/* function */ |
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ND_TCHECK2(*cp, 2); |
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function = EXTRACT_LE_16BITS(cp); |
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cp += 2; |
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ND_PRINT((ndo, ", %s", tok2str(fcode_str, " invalid (%u)", function))); |
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switch (function) { |
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case LOOPBACK_REPLY: |
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if (len < 4) |
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goto invalid; |
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/* receipt number */ |
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ND_TCHECK2(*cp, 2); |
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ND_PRINT((ndo, ", receipt number %u", EXTRACT_LE_16BITS(cp))); |
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cp += 2; |
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/* data */ |
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ND_PRINT((ndo, ", data (%u octets)", len - 4)); |
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ND_TCHECK2(*cp, len - 4); |
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break; |
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case LOOPBACK_FWDDATA: |
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if (len < 8) |
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goto invalid; |
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/* forwarding address */ |
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ND_TCHECK2(*cp, ETHER_ADDR_LEN); |
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ND_PRINT((ndo, ", forwarding address %s", etheraddr_string(ndo, cp))); |
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cp += ETHER_ADDR_LEN; |
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/* data */ |
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ND_PRINT((ndo, ", data (%u octets)", len - 8)); |
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ND_TCHECK2(*cp, len - 8); |
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break; |
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default: |
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ND_TCHECK2(*cp, len - 2); |
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break; |
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} |
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return; |
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invalid: |
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ND_PRINT((ndo, "%s", istr)); |
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ND_TCHECK2(*cp, ep - cp); |
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return; |
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trunc: |
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ND_PRINT((ndo, "%s", tstr)); |
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} |
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void |
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loopback_print(netdissect_options *ndo, const u_char *cp, const u_int len) |
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{ |
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const u_char *ep = cp + len; |
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uint16_t skipCount; |
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ND_PRINT((ndo, "Loopback")); |
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if (len < 2) |
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goto invalid; |
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/* skipCount */ |
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ND_TCHECK2(*cp, 2); |
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skipCount = EXTRACT_LE_16BITS(cp); |
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cp += 2; |
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ND_PRINT((ndo, ", skipCount %u", skipCount)); |
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if (skipCount % 8) |
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ND_PRINT((ndo, " (bogus)")); |
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if (skipCount > len - 2) |
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goto invalid; |
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loopback_message_print(ndo, cp + skipCount, len - 2 - skipCount); |
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return; |
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invalid: |
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ND_PRINT((ndo, "%s", istr)); |
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ND_TCHECK2(*cp, ep - cp); |
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return; |
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trunc: |
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ND_PRINT((ndo, "%s", tstr)); |
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} |
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