![Guy Harris](/assets/img/avatar_default.png)
Use WTAP_MAX_PACKET_SIZE_STANDARD, set to 256KB, for everything except for D-Bus captures. Use WTAP_MAX_PACKET_SIZE_DBUS, set to 128MB, for them, because that's the largest possible D-Bus message size. See https://bugs.freedesktop.org/show_bug.cgi?id=100220 for an example of the problems caused by limiting the snapshot length to 256KB for D-Bus. Have a snapshot length of 0 in a capture_file structure mean "there is no snapshot length for the file"; we don't need the has_snap field in that case, a value of 0 mean "no, we don't have a snapshot length". In dumpcap, start out with a pipe buffer size of 2KB, and grow it as necessary. When checking for a too-big packet from a pipe, check against the appropriate maximum - 128MB for DLT_DBUS, 256KB for everything else. Change-Id: Ib2ce7a0cf37b971fbc0318024fd011e18add8b20 Reviewed-on: https://code.wireshark.org/review/21952 Petri-Dish: Guy Harris <guy@alum.mit.edu> Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org> Reviewed-by: Guy Harris <guy@alum.mit.edu>
342 lines
12 KiB
C
342 lines
12 KiB
C
/* ipfix.c
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*
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* Wiretap Library
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* Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>
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*
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* File format support for ipfix file format
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* Copyright (c) 2010 by Hadriel Kaplan <hadrielk@yahoo.com>
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* with generous copying from other wiretaps, such as pcapng
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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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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/* File format reference:
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* RFC 5655 and 5101
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* http://tools.ietf.org/rfc/rfc5655
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* http://tools.ietf.org/rfc/rfc5101
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*
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* This wiretap is for an ipfix file format reader, per RFC 5655/5101.
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* All "records" in the file are IPFIX messages, beginning with an IPFIX
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* message header of 16 bytes as follows from RFC 5101:
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0 1 2 3
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Version Number | Length |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Export Time |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Sequence Number |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Observation Domain ID |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Figure F: IPFIX Message Header Format
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* which is then followed by one or more "Sets": Data Sets, Template Sets,
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* and Options Template Sets. Each Set then has one or more Records in
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* it.
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*
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* All IPFIX files are recorded in big-endian form (network byte order),
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* per the RFCs. That means if we're on a little-endian system, all
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* hell will break loose if we don't g_ntohX.
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*
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* Since wireshark already has an IPFIX dissector (implemented in
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* packet-netflow.c), this reader will just set that dissector upon
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* reading each message. Thus, an IPFIX Message is treated as a packet
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* as far as the dissector is concerned.
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*/
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#include "config.h"
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include "wtap-int.h"
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#include "file_wrappers.h"
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#include "ipfix.h"
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#include <wsutil/strtoi.h>
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#if 0
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#define ipfix_debug(...) g_warning(__VA_ARGS__)
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#else
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#define ipfix_debug(...)
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#endif
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#define RECORDS_FOR_IPFIX_CHECK 20
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static gboolean
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ipfix_read(wtap *wth, int *err, gchar **err_info,
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gint64 *data_offset);
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static gboolean
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ipfix_seek_read(wtap *wth, gint64 seek_off,
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struct wtap_pkthdr *phdr, Buffer *buf, int *err, gchar **err_info);
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#define IPFIX_VERSION 10
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/* ipfix: message header */
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typedef struct ipfix_message_header_s {
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guint16 version;
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guint16 message_length;
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guint32 export_time_secs;
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guint32 sequence_number;
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guint32 observation_id; /* might be 0 for none */
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/* x bytes msg_body */
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} ipfix_message_header_t;
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#define IPFIX_MSG_HDR_SIZE 16
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/* ipfix: common Set header for every Set type */
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typedef struct ipfix_set_header_s {
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guint16 set_type;
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guint16 set_length;
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/* x bytes set_body */
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} ipfix_set_header_t;
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#define IPFIX_SET_HDR_SIZE 4
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/* Read IPFIX message header from file. Return true on success. Set *err to
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* 0 on EOF, any other value for "real" errors (EOF is ok, since return
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* value is still FALSE)
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*/
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static gboolean
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ipfix_read_message_header(ipfix_message_header_t *pfx_hdr, FILE_T fh, int *err, gchar **err_info)
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{
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if (!wtap_read_bytes_or_eof(fh, pfx_hdr, IPFIX_MSG_HDR_SIZE, err, err_info))
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return FALSE;
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/* fix endianess, because IPFIX files are always big-endian */
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pfx_hdr->version = g_ntohs(pfx_hdr->version);
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pfx_hdr->message_length = g_ntohs(pfx_hdr->message_length);
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pfx_hdr->export_time_secs = g_ntohl(pfx_hdr->export_time_secs);
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pfx_hdr->sequence_number = g_ntohl(pfx_hdr->sequence_number);
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pfx_hdr->observation_id = g_ntohl(pfx_hdr->observation_id);
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/* is the version number one we expect? */
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if (pfx_hdr->version != IPFIX_VERSION) {
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/* Not an ipfix file. */
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*err = WTAP_ERR_BAD_FILE;
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*err_info = g_strdup_printf("ipfix: wrong version %d", pfx_hdr->version);
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return FALSE;
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}
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if (pfx_hdr->message_length < 16) {
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*err = WTAP_ERR_BAD_FILE;
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*err_info = g_strdup_printf("ipfix: message length %u is too short", pfx_hdr->message_length);
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return FALSE;
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}
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/* go back to before header */
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if (file_seek(fh, 0 - IPFIX_MSG_HDR_SIZE, SEEK_CUR, err) == -1) {
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ipfix_debug("ipfix_read: couldn't go back in file before header");
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return FALSE;
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}
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return TRUE;
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}
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/* Read IPFIX message header from file and fill in the struct wtap_pkthdr
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* for the packet, and, if that succeeds, read the packet data.
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* Return true on success. Set *err to 0 on EOF, any other value for "real"
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* errors (EOF is ok, since return value is still FALSE).
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*/
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static gboolean
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ipfix_read_message(FILE_T fh, struct wtap_pkthdr *phdr, Buffer *buf, int *err, gchar **err_info)
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{
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ipfix_message_header_t msg_hdr;
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if (!ipfix_read_message_header(&msg_hdr, fh, err, err_info))
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return FALSE;
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/*
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* The maximum value of msg_hdr.message_length is 65535, which is
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* less than WTAP_MAX_PACKET_SIZE_STANDARD will ever be, so we don't need
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* to check it.
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*/
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phdr->rec_type = REC_TYPE_PACKET;
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phdr->presence_flags = WTAP_HAS_TS;
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phdr->len = msg_hdr.message_length;
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phdr->caplen = msg_hdr.message_length;
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phdr->ts.secs = msg_hdr.export_time_secs;
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phdr->ts.nsecs = 0;
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return wtap_read_packet_bytes(fh, buf, msg_hdr.message_length, err, err_info);
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}
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/* classic wtap: open capture file. Return WTAP_OPEN_MINE on success,
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* WTAP_OPEN_NOT_MINE on normal failure like malformed format,
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* WTAP_OPEN_ERROR on bad error like file system
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*/
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wtap_open_return_val
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ipfix_open(wtap *wth, int *err, gchar **err_info)
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{
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gint i, n, records_for_ipfix_check = RECORDS_FOR_IPFIX_CHECK;
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gchar *s;
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guint16 checked_len = 0;
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ipfix_message_header_t msg_hdr;
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ipfix_set_header_t set_hdr;
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ipfix_debug("ipfix_open: opening file");
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/* number of records to scan before deciding if this really is IPFIX */
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if ((s = getenv("IPFIX_RECORDS_TO_CHECK")) != NULL) {
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if (ws_strtoi32(s, NULL, &n) && n > 0 && n < 101) {
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records_for_ipfix_check = n;
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}
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}
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/*
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* IPFIX is a little hard because there's no magic number; we look at
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* the first few records and see if they look enough like IPFIX
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* records.
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*/
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for (i = 0; i < records_for_ipfix_check; i++) {
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/* read first message header to check version */
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if (!ipfix_read_message_header(&msg_hdr, wth->fh, err, err_info)) {
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ipfix_debug("ipfix_open: couldn't read message header #%d with err code #%d (%s)",
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i, *err, *err_info);
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if (*err == WTAP_ERR_BAD_FILE) {
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*err = 0; /* not actually an error in this case */
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g_free(*err_info);
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*err_info = NULL;
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return WTAP_OPEN_NOT_MINE;
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}
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if (*err != 0 && *err != WTAP_ERR_SHORT_READ)
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return WTAP_OPEN_ERROR; /* real failure */
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/* else it's EOF */
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if (i < 1) {
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/* we haven't seen enough to prove this is a ipfix file */
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return WTAP_OPEN_NOT_MINE;
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}
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/*
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* If we got here, it's EOF and we haven't yet seen anything
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* that doesn't look like an IPFIX record - i.e. everything
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* we've seen looks like an IPFIX record - so we assume this
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* is an IPFIX file.
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*/
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break;
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}
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if (file_seek(wth->fh, IPFIX_MSG_HDR_SIZE, SEEK_CUR, err) == -1) {
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ipfix_debug("ipfix_open: failed seek to next message in file, %d bytes away",
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msg_hdr.message_length);
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return WTAP_OPEN_NOT_MINE;
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}
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checked_len = IPFIX_MSG_HDR_SIZE;
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/* check each Set in IPFIX Message for sanity */
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while (checked_len < msg_hdr.message_length) {
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if (!wtap_read_bytes(wth->fh, &set_hdr, IPFIX_SET_HDR_SIZE,
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err, err_info)) {
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if (*err == WTAP_ERR_SHORT_READ) {
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/* Not a valid IPFIX Set, so not an IPFIX file. */
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ipfix_debug("ipfix_open: error %d reading set", *err);
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return WTAP_OPEN_NOT_MINE;
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}
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/* A real I/O error; fail. */
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return WTAP_OPEN_ERROR;
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}
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set_hdr.set_length = g_ntohs(set_hdr.set_length);
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if ((set_hdr.set_length < IPFIX_SET_HDR_SIZE) ||
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((set_hdr.set_length + checked_len) > msg_hdr.message_length)) {
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ipfix_debug("ipfix_open: found invalid set_length of %d",
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set_hdr.set_length);
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return WTAP_OPEN_NOT_MINE;
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}
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if (file_seek(wth->fh, set_hdr.set_length - IPFIX_SET_HDR_SIZE,
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SEEK_CUR, err) == -1)
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{
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ipfix_debug("ipfix_open: failed seek to next set in file, %d bytes away",
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set_hdr.set_length - IPFIX_SET_HDR_SIZE);
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return WTAP_OPEN_ERROR;
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}
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checked_len += set_hdr.set_length;
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}
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}
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/* go back to beginning of file */
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if (file_seek (wth->fh, 0, SEEK_SET, err) != 0)
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{
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return WTAP_OPEN_ERROR;
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}
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/* all's good, this is a IPFIX file */
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wth->file_encap = WTAP_ENCAP_RAW_IPFIX;
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wth->snapshot_length = 0;
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wth->file_tsprec = WTAP_TSPREC_SEC;
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wth->subtype_read = ipfix_read;
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wth->subtype_seek_read = ipfix_seek_read;
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wth->file_type_subtype = WTAP_FILE_TYPE_SUBTYPE_IPFIX;
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return WTAP_OPEN_MINE;
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}
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/* classic wtap: read packet */
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static gboolean
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ipfix_read(wtap *wth, int *err, gchar **err_info, gint64 *data_offset)
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{
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*data_offset = file_tell(wth->fh);
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ipfix_debug("ipfix_read: data_offset is initially %" G_GINT64_MODIFIER "d", *data_offset);
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if (!ipfix_read_message(wth->fh, &wth->phdr, wth->frame_buffer, err, err_info)) {
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ipfix_debug("ipfix_read: couldn't read message header with code: %d\n, and error '%s'",
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*err, *err_info);
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return FALSE;
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}
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return TRUE;
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}
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/* classic wtap: seek to file position and read packet */
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static gboolean
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ipfix_seek_read(wtap *wth, gint64 seek_off, struct wtap_pkthdr *phdr,
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Buffer *buf, int *err, gchar **err_info)
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{
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/* seek to the right file position */
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if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1) {
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ipfix_debug("ipfix_seek_read: couldn't read message header with code: %d\n, and error '%s'",
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*err, *err_info);
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return FALSE; /* Seek error */
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}
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ipfix_debug("ipfix_seek_read: reading at offset %" G_GINT64_MODIFIER "u", seek_off);
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if (!ipfix_read_message(wth->random_fh, phdr, buf, err, err_info)) {
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ipfix_debug("ipfix_seek_read: couldn't read message header");
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if (*err == 0)
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*err = WTAP_ERR_SHORT_READ;
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return FALSE;
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}
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return TRUE;
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}
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/*
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* Editor modelines - http://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 4
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* tab-width: 8
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* indent-tabs-mode: nil
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* End:
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*
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* vi: set shiftwidth=4 tabstop=8 expandtab:
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* :indentSize=4:tabSize=8:noTabs=true:
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*/
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