149 lines
5.0 KiB
C
149 lines
5.0 KiB
C
/*
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* This file implements decoding of ZeroMQ network protocol(s).
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*
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*
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* Copyright (c) 2013 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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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <tcpdump-stdinc.h>
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#include <stdio.h>
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#include "interface.h"
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#include "extract.h"
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/* Maximum number of ZMTP/1.0 frame body bytes (without the flags) to dump in
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* hex and ASCII under a single "-v" flag.
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*/
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#define VBYTES 128
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/*
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* Below is an excerpt from the "13/ZMTP" specification:
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*
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* A ZMTP message consists of 1 or more frames.
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*
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* A ZMTP frame consists of a length, followed by a flags field and a frame
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* body of (length - 1) octets. Note: the length includes the flags field, so
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* an empty frame has a length of 1.
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*
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* For frames with a length of 1 to 254 octets, the length SHOULD BE encoded
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* as a single octet. The minimum valid length of a frame is 1 octet, thus a
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* length of 0 is invalid and such frames SHOULD be discarded silently.
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*
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* For frames with lengths of 255 and greater, the length SHALL BE encoded as
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* a single octet with the value 255, followed by the length encoded as a
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* 64-bit unsigned integer in network byte order. For frames with lengths of
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* 1 to 254 octets this encoding MAY be also used.
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*
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* The flags field consists of a single octet containing various control
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* flags. Bit 0 is the least significant bit.
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*
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* - Bit 0 (MORE): More frames to follow. A value of 0 indicates that there
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* are no more frames to follow. A value of 1 indicates that more frames
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* will follow. On messages consisting of a single frame the MORE flag MUST
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* be 0.
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*
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* - Bits 1-7: Reserved. Bits 1-7 are reserved for future use and SHOULD be
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* zero.
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*/
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static const u_char *
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zmtp1_print_frame(const u_char *cp, const u_char *ep) {
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u_int64_t body_len_declared, body_len_captured, header_len;
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u_int8_t flags;
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printf("\n\t");
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TCHECK2(*cp, 1); /* length/0xFF */
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if (cp[0] != 0xFF) {
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header_len = 1; /* length */
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body_len_declared = cp[0];
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if (body_len_declared == 0)
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return cp + header_len; /* skip to next frame */
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printf(" frame flags+body (8-bit) length %"PRIu8"", cp[0]);
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TCHECK2(*cp, header_len + 1); /* length, flags */
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flags = cp[1];
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} else {
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header_len = 1 + 8; /* 0xFF, length */
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printf(" frame flags+body (64-bit) length");
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TCHECK2(*cp, header_len); /* 0xFF, length */
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body_len_declared = EXTRACT_64BITS(cp + 1);
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if (body_len_declared == 0)
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return cp + header_len; /* skip to next frame */
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printf(" %"PRIu64"", body_len_declared);
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TCHECK2(*cp, header_len + 1); /* 0xFF, length, flags */
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flags = cp[9];
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}
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body_len_captured = ep - cp - header_len;
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if (body_len_declared > body_len_captured)
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printf(" (%"PRIu64" captured)", body_len_captured);
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printf(", flags 0x%02"PRIx8"", flags);
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if (vflag) {
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u_int64_t body_len_printed = MIN(body_len_captured, body_len_declared);
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printf(" (%s|%s|%s|%s|%s|%s|%s|%s)",
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flags & 0x80 ? "MBZ" : "-",
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flags & 0x40 ? "MBZ" : "-",
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flags & 0x20 ? "MBZ" : "-",
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flags & 0x10 ? "MBZ" : "-",
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flags & 0x08 ? "MBZ" : "-",
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flags & 0x04 ? "MBZ" : "-",
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flags & 0x02 ? "MBZ" : "-",
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flags & 0x01 ? "MORE" : "-");
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if (vflag == 1)
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body_len_printed = MIN(VBYTES + 1, body_len_printed);
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if (body_len_printed > 1) {
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printf(", first %"PRIu64" byte(s) of body:", body_len_printed - 1);
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hex_and_ascii_print("\n\t ", cp + header_len + 1, body_len_printed - 1);
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printf("\n");
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}
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}
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TCHECK2(*cp, header_len + body_len_declared); /* Next frame within the buffer ? */
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return cp + header_len + body_len_declared;
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trunc:
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printf(" [|zmtp1]");
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return ep;
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}
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void
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zmtp1_print(const u_char *cp, u_int len) {
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const u_char *ep = MIN(snapend, cp + len);
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printf(": ZMTP/1.0");
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while (cp < ep)
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cp = zmtp1_print_frame(cp, ep);
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}
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