![Alexis La Goutte](/assets/img/avatar_default.png)
pcapio.c: bug in libpcap_write_interface_description_block The attached patch fixes a copy_and_paste error in the code of the function libpcap_write_interface_description_block(): strlen(name) instead of strlen(filter). svn path=/trunk/; revision=40423
535 lines
17 KiB
C
535 lines
17 KiB
C
/* pcapio.c
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* Our own private code for writing libpcap files when capturing.
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*
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* We have these because we want a way to open a stream for output given
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* only a file descriptor. libpcap 0.9[.x] has "pcap_dump_fopen()", which
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* provides that, but
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*
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* 1) earlier versions of libpcap doesn't have it
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*
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* and
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*
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* 2) WinPcap doesn't have it, because a file descriptor opened
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* by code built for one version of the MSVC++ C library
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* can't be used by library routines built for another version
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* (e.g., threaded vs. unthreaded).
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*
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* Libpcap's pcap_dump() also doesn't return any error indications.
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*
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* $Id$
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* Derived from code in the Wiretap Library
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* Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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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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#ifdef HAVE_LIBPCAP
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#include <stdlib.h>
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#include <stdio.h>
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#include <errno.h>
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#include <string.h>
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#include <pcap.h>
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#include <glib.h>
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#include "pcapio.h"
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/* Magic numbers in "libpcap" files.
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"libpcap" file records are written in the byte order of the host that
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writes them, and the reader is expected to fix this up.
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PCAP_MAGIC is the magic number, in host byte order; PCAP_SWAPPED_MAGIC
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is a byte-swapped version of that.
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PCAP_NSEC_MAGIC is for Ulf Lamping's modified "libpcap" format,
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which uses the same common file format as PCAP_MAGIC, but the
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timestamps are saved in nanosecond resolution instead of microseconds.
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PCAP_SWAPPED_NSEC_MAGIC is a byte-swapped version of that. */
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#define PCAP_MAGIC 0xa1b2c3d4
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#define PCAP_SWAPPED_MAGIC 0xd4c3b2a1
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#define PCAP_NSEC_MAGIC 0xa1b23c4d
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#define PCAP_SWAPPED_NSEC_MAGIC 0x4d3cb2a1
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/* "libpcap" file header. */
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struct pcap_hdr {
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guint32 magic; /* magic number */
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guint16 version_major; /* major version number */
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guint16 version_minor; /* minor version number */
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gint32 thiszone; /* GMT to local correction */
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guint32 sigfigs; /* accuracy of timestamps */
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guint32 snaplen; /* max length of captured packets, in octets */
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guint32 network; /* data link type */
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};
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/* "libpcap" record header. */
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struct pcaprec_hdr {
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guint32 ts_sec; /* timestamp seconds */
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guint32 ts_usec; /* timestamp microseconds (nsecs for PCAP_NSEC_MAGIC) */
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guint32 incl_len; /* number of octets of packet saved in file */
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guint32 orig_len; /* actual length of packet */
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};
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/* Magic numbers in ".pcapng" files.
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*
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* .pcapng file records are written in the byte order of the host that
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* writes them, and the reader is expected to fix this up.
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* PCAPNG_MAGIC is the magic number, in host byte order;
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* PCAPNG_SWAPPED_MAGIC is a byte-swapped version of that.
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*/
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#define PCAPNG_MAGIC 0x1A2B3C4D
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#define PCAPNG_SWAPPED_MAGIC 0xD4C3B2A1
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/* Currently we are only supporting the initial version of
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the file format. */
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#define PCAPNG_MAJOR_VERSION 1
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#define PCAPNG_MINOR_VERSION 0
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/* Section Header Block without options and trailing Block Total Length */
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struct shb {
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guint32 block_type;
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guint32 block_total_length;
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guint32 byte_order_magic;
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guint16 major_version;
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guint16 minor_version;
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guint64 section_length;
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};
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#define SECTION_HEADER_BLOCK_TYPE 0x0A0D0D0A
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/* Interface Decription Block without options and trailing Block Total Length */
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struct idb {
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guint32 block_type;
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guint32 block_total_length;
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guint16 link_type;
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guint16 reserved;
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guint32 snap_len;
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};
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#define INTERFACE_DESCRIPTION_BLOCK_TYPE 0x00000001
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/* Interface Statistics Block without actual packet, options, and trailing
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Block Total Length */
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struct isb {
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guint32 block_type;
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guint32 block_total_length;
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guint32 interface_id;
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guint32 timestamp_high;
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guint32 timestamp_low;
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};
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#define INTERFACE_STATISTICS_BLOCK_TYPE 0x00000005
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/* Enhanced Packet Block without actual packet, options, and trailing
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Block Total Length */
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struct epb {
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guint32 block_type;
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guint32 block_total_length;
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guint32 interface_id;
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guint32 timestamp_high;
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guint32 timestamp_low;
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guint32 captured_len;
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guint32 packet_len;
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};
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#define ENHANCED_PACKET_BLOCK_TYPE 0x00000006
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struct option {
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guint16 type;
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guint16 value_length;
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};
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#define OPT_ENDOFOPT 0
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#define OPT_COMMENT 1 /* currently not used */
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#define SHB_HARDWARE 2 /* currently not used */
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#define SHB_OS 3 /* currently not used */
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#define SHB_USERAPPL 4
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#define IDB_NAME 2
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#define IDB_FILTER 11
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#define ISB_IFRECV 4
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#define ISB_IFDROP 5
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#define ISB_FILTERACCEPT 6
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#define ADD_PADDING(x) ((((x) + 3) >> 2) << 2)
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#define WRITE_DATA(file_pointer, data_pointer, data_length, written_length, error_pointer) \
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{ \
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do { \
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size_t nwritten; \
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\
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nwritten = fwrite(data_pointer, 1, data_length, file_pointer); \
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if (nwritten != data_length) { \
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if (nwritten == 0 && ferror(file_pointer)) { \
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*error_pointer = errno; \
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} else { \
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*error_pointer = 0; \
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} \
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return FALSE; \
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} \
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written_length += (long)nwritten; \
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} while (0); \
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}
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/* Returns a FILE * to write to on success, NULL on failure */
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FILE *
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libpcap_fdopen(int fd, int *err)
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{
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FILE *fp;
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fp = fdopen(fd, "wb");
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if (fp == NULL) {
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*err = errno;
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}
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return fp;
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}
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/* Write the file header to a dump file.
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Returns TRUE on success, FALSE on failure.
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Sets "*err" to an error code, or 0 for a short write, on failure*/
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gboolean
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libpcap_write_file_header(FILE *fp, int linktype, int snaplen, long *bytes_written, int *err)
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{
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struct pcap_hdr file_hdr;
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size_t nwritten;
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file_hdr.magic = PCAP_MAGIC;
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/* current "libpcap" format is 2.4 */
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file_hdr.version_major = 2;
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file_hdr.version_minor = 4;
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file_hdr.thiszone = 0; /* XXX - current offset? */
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file_hdr.sigfigs = 0; /* unknown, but also apparently unused */
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file_hdr.snaplen = snaplen;
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file_hdr.network = linktype;
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nwritten = fwrite(&file_hdr, 1, sizeof(file_hdr), fp);
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if (nwritten != sizeof(file_hdr)) {
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if (nwritten == 0 && ferror(fp))
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*err = errno;
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else
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*err = 0; /* short write */
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return FALSE;
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}
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*bytes_written += sizeof(file_hdr);
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return TRUE;
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}
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/* Write a record for a packet to a dump file.
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Returns TRUE on success, FALSE on failure. */
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gboolean
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libpcap_write_packet(FILE *fp, const struct pcap_pkthdr *phdr, const u_char *pd,
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long *bytes_written, int *err)
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{
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struct pcaprec_hdr rec_hdr;
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size_t nwritten;
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rec_hdr.ts_sec = phdr->ts.tv_sec;
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rec_hdr.ts_usec = phdr->ts.tv_usec;
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rec_hdr.incl_len = phdr->caplen;
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rec_hdr.orig_len = phdr->len;
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nwritten = fwrite(&rec_hdr, 1, sizeof rec_hdr, fp);
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if (nwritten != sizeof rec_hdr) {
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if (nwritten == 0 && ferror(fp))
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*err = errno;
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else
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*err = 0; /* short write */
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return FALSE;
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}
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*bytes_written += sizeof rec_hdr;
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nwritten = fwrite(pd, 1, phdr->caplen, fp);
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if (nwritten != phdr->caplen) {
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if (nwritten == 0 && ferror(fp))
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*err = errno;
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else
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*err = 0; /* short write */
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return FALSE;
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}
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*bytes_written += phdr->caplen;
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return TRUE;
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}
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gboolean
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libpcap_write_session_header_block(FILE *fp,
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const char *appname,
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long *bytes_written,
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int *err)
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{
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struct shb shb;
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struct option option;
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guint32 block_total_length;
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const guint32 padding = 0;
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block_total_length = sizeof(struct shb) +
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sizeof(guint32);
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if ((strlen(appname) > 0) && (strlen(appname) < G_MAXUINT16)) {
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block_total_length += 2 * sizeof(struct option) +
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(guint16)(ADD_PADDING(strlen(appname) + 1));
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}
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/* write shb header */
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shb.block_type = SECTION_HEADER_BLOCK_TYPE;
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shb.block_total_length = block_total_length;
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shb.byte_order_magic = PCAPNG_MAGIC;
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shb.major_version = PCAPNG_MAJOR_VERSION;
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shb.minor_version = PCAPNG_MINOR_VERSION;
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shb.section_length = -1;
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WRITE_DATA(fp, &shb, sizeof(struct shb), *bytes_written, err);
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if ((strlen(appname) > 0) && (strlen(appname) < G_MAXUINT16)) {
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/* write shb_userappl options */
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option.type = SHB_USERAPPL;
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option.value_length = (guint16)(strlen(appname) + 1);
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WRITE_DATA(fp, &option, sizeof(struct option), *bytes_written, err);
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WRITE_DATA(fp, appname, strlen(appname) + 1, *bytes_written, err);
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if ((strlen(appname) + 1) % 4) {
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WRITE_DATA(fp, &padding, 4 - (strlen(appname) + 1) % 4, *bytes_written, err);
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}
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/* write last option */
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option.type = OPT_ENDOFOPT;
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option.value_length = 0;
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WRITE_DATA(fp, &option, sizeof(struct option), *bytes_written, err);
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}
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/* write the trailing block total length */
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WRITE_DATA(fp, &block_total_length, sizeof(guint32), *bytes_written, err);
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return TRUE;
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}
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gboolean
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libpcap_write_interface_description_block(FILE *fp,
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const char *name,
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const char *filter,
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int link_type,
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int snap_len,
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long *bytes_written,
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int *err)
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{
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struct idb idb;
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struct option option;
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guint32 block_total_length;
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const guint32 padding = 0;
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block_total_length = sizeof(struct idb) + sizeof(guint32);
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if ((strlen(name) > 0) && (strlen(name) < G_MAXUINT16)) {
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block_total_length += sizeof(struct option) +
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(guint16)(ADD_PADDING(strlen(name) + 1));
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}
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if ((strlen(filter) > 0) && (strlen(filter) < G_MAXUINT16)) {
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block_total_length += sizeof(struct option) +
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(guint16)(ADD_PADDING(strlen(filter) + 1));
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}
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if (((strlen(name) > 0) && (strlen(name) < G_MAXUINT16)) ||
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((strlen(filter) > 0) && (strlen(filter) < G_MAXUINT16))) {
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block_total_length += sizeof(struct option);
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}
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/* write block header */
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idb.block_type = INTERFACE_DESCRIPTION_BLOCK_TYPE;
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idb.block_total_length = block_total_length;
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idb.link_type = link_type;
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idb.reserved = 0;
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idb.snap_len = snap_len;
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WRITE_DATA(fp, &idb, sizeof(struct idb), *bytes_written, err);
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/* write interface name string if applicable */
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if ((strlen(name) > 0) && (strlen(name) < G_MAXUINT16)) {
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option.type = IDB_NAME;
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option.value_length = (guint16)(strlen(name) + 1);
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WRITE_DATA(fp, &option, sizeof(struct option), *bytes_written, err);
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WRITE_DATA(fp, name, strlen(name) + 1, *bytes_written, err);
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if ((strlen(name) + 1) % 4) {
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WRITE_DATA(fp, &padding, 4 - (strlen(name) + 1) % 4 , *bytes_written, err);
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}
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}
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/* write filter string if applicable */
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if ((strlen(filter) > 0) && (strlen(filter) < G_MAXUINT16)) {
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option.type = IDB_FILTER;
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option.value_length = (guint16)(strlen(filter) + 1);
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WRITE_DATA(fp, &option, sizeof(struct option), *bytes_written, err);
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WRITE_DATA(fp, filter, strlen(filter) + 1, *bytes_written, err);
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if ((strlen(filter) + 1) % 4) {
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WRITE_DATA(fp, &padding, 4 - (strlen(filter) + 1) % 4 , *bytes_written, err);
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}
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}
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/* write endofopt option if there were any options */
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if (((strlen(name) > 0) && (strlen(name) < G_MAXUINT16)) ||
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((strlen(filter) > 0) && (strlen(filter) < G_MAXUINT16))) {
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option.type = OPT_ENDOFOPT;
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option.value_length = 0;
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WRITE_DATA(fp, &option, sizeof(struct option), *bytes_written, err);
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}
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/* write the trailing Block Total Length */
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WRITE_DATA(fp, &block_total_length, sizeof(guint32), *bytes_written, err);
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return TRUE;
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}
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/* Write a record for a packet to a dump file.
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Returns TRUE on success, FALSE on failure. */
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gboolean
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libpcap_write_enhanced_packet_block(FILE *fp,
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const struct pcap_pkthdr *phdr,
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guint32 interface_id,
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const u_char *pd,
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long *bytes_written,
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int *err)
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{
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struct epb epb;
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guint32 block_total_length;
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guint64 timestamp;
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const guint32 padding = 0;
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block_total_length = sizeof(struct epb) +
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ADD_PADDING(phdr->caplen) +
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sizeof(guint32);
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timestamp = (guint64)(phdr->ts.tv_sec) * 1000000 +
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(guint64)(phdr->ts.tv_usec);
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epb.block_type = ENHANCED_PACKET_BLOCK_TYPE;
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epb.block_total_length = block_total_length;
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epb.interface_id = interface_id;
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epb.timestamp_high = (guint32)((timestamp>>32) & 0xffffffff);
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epb.timestamp_low = (guint32)(timestamp & 0xffffffff);
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epb.captured_len = phdr->caplen;
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epb.packet_len = phdr->len;
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WRITE_DATA(fp, &epb, sizeof(struct epb), *bytes_written, err);
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WRITE_DATA(fp, pd, phdr->caplen, *bytes_written, err);
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if (phdr->caplen % 4) {
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WRITE_DATA(fp, &padding, 4 - phdr->caplen % 4, *bytes_written, err);
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}
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WRITE_DATA(fp, &block_total_length, sizeof(guint32), *bytes_written, err);
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return TRUE;
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}
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gboolean
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libpcap_write_interface_statistics_block(FILE *fp,
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guint32 interface_id,
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pcap_t *pd,
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long *bytes_written,
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int *err)
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{
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struct isb isb;
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#ifdef _WIN32
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FILETIME now;
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#else
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struct timeval now;
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#endif
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struct option option;
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struct pcap_stat stats;
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guint32 block_total_length;
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guint64 timestamp;
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guint64 counter;
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gboolean stats_retrieved;
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#ifdef _WIN32
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/*
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* Current time, represented as 100-nanosecond intervals since
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* January 1, 1601, 00:00:00 UTC.
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*
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* I think DWORD might be signed, so cast both parts of "now"
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* to guint32 so that the sign bit doesn't get treated specially.
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*/
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GetSystemTimeAsFileTime(&now);
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timestamp = (((guint64)(guint32)now.dwHighDateTime) << 32) +
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(guint32)now.dwLowDateTime;
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/*
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* Convert to same thing but as 1-microsecond, i.e. 1000-nanosecond,
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* intervals.
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*/
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timestamp /= 10;
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/*
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* Subtract difference, in microseconds, between January 1, 1601
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* 00:00:00 UTC and January 1, 1970, 00:00:00 UTC.
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*/
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timestamp -= G_GINT64_CONSTANT(11644473600000000U);
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#else
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/*
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* Current time, represented as seconds and microseconds since
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* January 1, 1970, 00:00:00 UTC.
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*/
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gettimeofday(&now, NULL);
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/*
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* Convert to delta in microseconds.
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*/
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timestamp = (guint64)(now.tv_sec) * 1000000 +
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(guint64)(now.tv_usec);
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#endif
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if (pcap_stats(pd, &stats) < 0) {
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stats_retrieved = FALSE;
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g_warning("pcap_stats() failed.");
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} else {
|
|
stats_retrieved = TRUE;
|
|
}
|
|
block_total_length = sizeof(struct isb) +
|
|
sizeof(guint32);
|
|
if (stats_retrieved) {
|
|
block_total_length += 3 * sizeof(struct option) + 2 * sizeof(guint64);
|
|
}
|
|
isb.block_type = INTERFACE_STATISTICS_BLOCK_TYPE;
|
|
isb.block_total_length = block_total_length;
|
|
isb.interface_id = interface_id;
|
|
isb.timestamp_high = (guint32)((timestamp>>32) & 0xffffffff);
|
|
isb.timestamp_low = (guint32)(timestamp & 0xffffffff);
|
|
WRITE_DATA(fp, &isb, sizeof(struct isb), *bytes_written, err);
|
|
if (stats_retrieved) {
|
|
/* */
|
|
option.type = ISB_IFRECV;
|
|
option.value_length = sizeof(guint64);
|
|
counter = stats.ps_recv;
|
|
WRITE_DATA(fp, &option, sizeof(struct option), *bytes_written, err);
|
|
WRITE_DATA(fp, &counter, sizeof(guint64), *bytes_written, err);
|
|
/* */
|
|
option.type = ISB_IFDROP;
|
|
option.value_length = sizeof(guint64);
|
|
counter = stats.ps_drop;
|
|
WRITE_DATA(fp, &option, sizeof(struct option), *bytes_written, err);
|
|
WRITE_DATA(fp, &counter, sizeof(guint64), *bytes_written, err);
|
|
/* last option */
|
|
option.type = OPT_ENDOFOPT;
|
|
option.value_length = 0;
|
|
WRITE_DATA(fp, &option, sizeof(struct option), *bytes_written, err);
|
|
}
|
|
WRITE_DATA(fp, &block_total_length, sizeof(guint32), *bytes_written, err);
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
gboolean
|
|
libpcap_dump_flush(FILE *pd, int *err)
|
|
{
|
|
if (fflush(pd) == EOF) {
|
|
if (err != NULL)
|
|
*err = errno;
|
|
return FALSE;
|
|
}
|
|
return TRUE;
|
|
}
|
|
|
|
gboolean
|
|
libpcap_dump_close(FILE *pd, int *err)
|
|
{
|
|
if (fclose(pd) == EOF) {
|
|
if (err != NULL)
|
|
*err = errno;
|
|
return FALSE;
|
|
}
|
|
return TRUE;
|
|
}
|
|
|
|
#endif /* HAVE_LIBPCAP */
|