2 * Copyright (c) 2014 The TCPDUMP project
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14 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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28 /* \summary: Loopback Protocol printer */
31 * originally defined as the Ethernet Configuration Testing Protocol.
32 * specification: http://www.mit.edu/people/jhawk/ctp.pdf
39 #include <netdissect-stdinc.h>
41 #include "netdissect.h"
44 #include "addrtoname.h"
46 static const char tstr[] = " [|loopback]";
48 #define LOOPBACK_REPLY 1
49 #define LOOPBACK_FWDDATA 2
51 static const struct tok fcode_str[] = {
52 { LOOPBACK_REPLY, "Reply" },
53 { LOOPBACK_FWDDATA, "Forward Data" },
58 loopback_message_print(netdissect_options *ndo, const u_char *cp, const u_int len)
60 const u_char *ep = cp + len;
67 function = EXTRACT_LE_16BITS(cp);
69 ND_PRINT((ndo, ", %s", tok2str(fcode_str, " invalid (%u)", function)));
77 ND_PRINT((ndo, ", receipt number %u", EXTRACT_LE_16BITS(cp)));
80 ND_PRINT((ndo, ", data (%u octets)", len - 4));
81 ND_TCHECK2(*cp, len - 4);
83 case LOOPBACK_FWDDATA:
86 /* forwarding address */
87 ND_TCHECK2(*cp, ETHER_ADDR_LEN);
88 ND_PRINT((ndo, ", forwarding address %s", etheraddr_string(ndo, cp)));
91 ND_PRINT((ndo, ", data (%u octets)", len - 8));
92 ND_TCHECK2(*cp, len - 8);
95 ND_TCHECK2(*cp, len - 2);
101 ND_PRINT((ndo, "%s", istr));
102 ND_TCHECK2(*cp, ep - cp);
105 ND_PRINT((ndo, "%s", tstr));
109 loopback_print(netdissect_options *ndo, const u_char *cp, const u_int len)
111 const u_char *ep = cp + len;
114 ND_PRINT((ndo, "Loopback"));
119 skipCount = EXTRACT_LE_16BITS(cp);
121 ND_PRINT((ndo, ", skipCount %u", skipCount));
123 ND_PRINT((ndo, " (bogus)"));
124 if (skipCount > len - 2)
126 loopback_message_print(ndo, cp + skipCount, len - 2 - skipCount);
130 ND_PRINT((ndo, "%s", istr));
131 ND_TCHECK2(*cp, ep - cp);
134 ND_PRINT((ndo, "%s", tstr));