1/*
2 * This file implements decoding of ZeroMQ network protocol(s).
3 *
4 *
5 * Copyright (c) 2013 The TCPDUMP project
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
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.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
20 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
21 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
23 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
24 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
25 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
27 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28 * POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#ifdef HAVE_CONFIG_H
32#include "config.h"
33#endif
34
35#include <tcpdump-stdinc.h>
36
37#include <stdio.h>
38
39#include "interface.h"
40#include "extract.h"
41
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.
44 */
45#define VBYTES 128
46
47/*
48 * Below is an excerpt from the "13/ZMTP" specification:
49 *
50 * A ZMTP message consists of 1 or more frames.
51 *
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.
55 *
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.
59 *
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.
64 *
65 * The flags field consists of a single octet containing various control
66 * flags. Bit 0 is the least significant bit.
67 *
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
71 *   be 0.
72 *
73 * - Bits 1-7: Reserved. Bits 1-7 are reserved for future use and SHOULD be
74 *   zero.
75 */
76
77static const u_char *
78zmtp1_print_frame(const u_char *cp, const u_char *ep) {
79	u_int64_t body_len_declared, body_len_captured, header_len;
80	u_int8_t flags;
81
82	printf("\n\t");
83	TCHECK2(*cp, 1); /* length/0xFF */
84
85	if (cp[0] != 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 */
92		flags = cp[1];
93	} else {
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 */
102		flags = cp[9];
103	}
104
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);
109
110	if (vflag) {
111		u_int64_t body_len_printed = MIN(body_len_captured, body_len_declared);
112
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" : "-");
122
123		if (vflag == 1)
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);
128			printf("\n");
129		}
130	}
131
132	TCHECK2(*cp, header_len + body_len_declared); /* Next frame within the buffer ? */
133	return cp + header_len + body_len_declared;
134
135trunc:
136	printf(" [|zmtp1]");
137	return ep;
138}
139
140void
141zmtp1_print(const u_char *cp, u_int len) {
142	const u_char *ep = MIN(snapend, cp + len);
143
144	printf(": ZMTP/1.0");
145	while (cp < ep)
146		cp = zmtp1_print_frame(cp, ep);
147}
148
149