2 * This file implements decoding of ZeroMQ network protocol(s).
5 * Copyright (c) 2013 The TCPDUMP project
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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20 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
21 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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35 #include <tcpdump-stdinc.h>
39 #include "interface.h"
42 /* Maximum number of ZMTP/1.0 frame body bytes (without the flags) to dump in
43 * hex and ASCII under a single "-v" flag.
48 * Below is an excerpt from the "13/ZMTP" specification:
50 * A ZMTP message consists of 1 or more frames.
52 * A ZMTP frame consists of a length, followed by a flags field and a frame
53 * body of (length - 1) octets. Note: the length includes the flags field, so
54 * an empty frame has a length of 1.
56 * For frames with a length of 1 to 254 octets, the length SHOULD BE encoded
57 * as a single octet. The minimum valid length of a frame is 1 octet, thus a
58 * length of 0 is invalid and such frames SHOULD be discarded silently.
60 * For frames with lengths of 255 and greater, the length SHALL BE encoded as
61 * a single octet with the value 255, followed by the length encoded as a
62 * 64-bit unsigned integer in network byte order. For frames with lengths of
63 * 1 to 254 octets this encoding MAY be also used.
65 * The flags field consists of a single octet containing various control
66 * flags. Bit 0 is the least significant bit.
68 * - Bit 0 (MORE): More frames to follow. A value of 0 indicates that there
69 * are no more frames to follow. A value of 1 indicates that more frames
70 * will follow. On messages consisting of a single frame the MORE flag MUST
73 * - Bits 1-7: Reserved. Bits 1-7 are reserved for future use and SHOULD be
78 zmtp1_print_frame(const u_char *cp, const u_char *ep) {
79 u_int64_t body_len_declared, body_len_captured, header_len;
83 TCHECK2(*cp, 1); /* length/0xFF */
86 header_len = 1; /* length */
87 body_len_declared = cp[0];
88 if (body_len_declared == 0)
89 return cp + header_len; /* skip to next frame */
90 printf(" frame flags+body (8-bit) length %"PRIu8"", cp[0]);
91 TCHECK2(*cp, header_len + 1); /* length, flags */
94 header_len = 1 + 8; /* 0xFF, length */
95 printf(" frame flags+body (64-bit) length");
96 TCHECK2(*cp, header_len); /* 0xFF, length */
97 body_len_declared = EXTRACT_64BITS(cp + 1);
98 if (body_len_declared == 0)
99 return cp + header_len; /* skip to next frame */
100 printf(" %"PRIu64"", body_len_declared);
101 TCHECK2(*cp, header_len + 1); /* 0xFF, length, flags */
105 body_len_captured = ep - cp - header_len;
106 if (body_len_declared > body_len_captured)
107 printf(" (%"PRIu64" captured)", body_len_captured);
108 printf(", flags 0x%02"PRIx8"", flags);
111 u_int64_t body_len_printed = MIN(body_len_captured, body_len_declared);
113 printf(" (%s|%s|%s|%s|%s|%s|%s|%s)",
114 flags & 0x80 ? "MBZ" : "-",
115 flags & 0x40 ? "MBZ" : "-",
116 flags & 0x20 ? "MBZ" : "-",
117 flags & 0x10 ? "MBZ" : "-",
118 flags & 0x08 ? "MBZ" : "-",
119 flags & 0x04 ? "MBZ" : "-",
120 flags & 0x02 ? "MBZ" : "-",
121 flags & 0x01 ? "MORE" : "-");
124 body_len_printed = MIN(VBYTES + 1, body_len_printed);
125 if (body_len_printed > 1) {
126 printf(", first %"PRIu64" byte(s) of body:", body_len_printed - 1);
127 hex_and_ascii_print("\n\t ", cp + header_len + 1, body_len_printed - 1);
132 TCHECK2(*cp, header_len + body_len_declared); /* Next frame within the buffer ? */
133 return cp + header_len + body_len_declared;
141 zmtp1_print(const u_char *cp, u_int len) {
142 const u_char *ep = MIN(snapend, cp + len);
144 printf(": ZMTP/1.0");
146 cp = zmtp1_print_frame(cp, ep);