nexmon – Rev 1
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/* netscreen.c
*
* Juniper NetScreen snoop output parser
* Created by re-using a lot of code from cosine.c
* Copyright (c) 2007 by Sake Blok <sake@euronet.nl>
*
* Wiretap Library
* Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "config.h"
#include "wtap-int.h"
#include "netscreen.h"
#include "file_wrappers.h"
#include <stdlib.h>
#include <string.h>
/* XXX TODO:
*
* o Construct a list of interfaces, with interface names, give
* them link-layer types based on the interface name and packet
* data, and supply interface IDs with each packet (i.e., make
* this supply a pcap-ng-style set of interfaces and associate
* packets with interfaces). This is probably the right way
* to "Pass the interface names and the traffic direction to either
* the frame-structure, a pseudo-header or use PPI." See the
* message at
*
* http://www.wireshark.org/lists/wireshark-dev/200708/msg00029.html
*
* to see whether any further discussion is still needed. I suspect
* it doesn't; pcap-NG existed at the time, as per the final
* message in that thread:
*
* http://www.wireshark.org/lists/wireshark-dev/200708/msg00039.html
*
* but I don't think we fully *supported* it at that point. Now
* that we do, we have the infrastructure to support this, except
* that we currently have no way to translate interface IDs to
* interface names in the "frame" dissector or to supply interface
* information as part of the packet metadata from Wiretap modules.
* That should be fixed so that we can show interface information,
* such as the interface name, in packet dissections from, for example,
* pcap-NG captures.
*/
static gboolean info_line(const gchar *line);
static gint64 netscreen_seek_next_packet(wtap *wth, int *err, gchar **err_info,
char *hdr);
static gboolean netscreen_check_file_type(wtap *wth, int *err,
gchar **err_info);
static gboolean netscreen_read(wtap *wth, int *err, gchar **err_info,
gint64 *data_offset);
static gboolean netscreen_seek_read(wtap *wth, gint64 seek_off,
struct wtap_pkthdr *phdr, Buffer *buf,
int *err, gchar **err_info);
static gboolean parse_netscreen_packet(FILE_T fh, struct wtap_pkthdr *phdr,
Buffer* buf, char *line, int *err, gchar **err_info);
static int parse_single_hex_dump_line(char* rec, guint8 *buf,
guint byte_offset);
/* Returns TRUE if the line appears to be a line with protocol info.
Otherwise it returns FALSE. */
static gboolean info_line(const gchar *line)
{
int i=NETSCREEN_SPACES_ON_INFO_LINE;
while (i-- > 0) {
if (g_ascii_isspace(*line)) {
line++;
continue;
} else {
return FALSE;
}
}
return TRUE;
}
/* Seeks to the beginning of the next packet, and returns the
byte offset. Copy the header line to hdr. Returns -1 on failure,
and sets "*err" to the error and sets "*err_info" to null or an
additional error string. */
static gint64 netscreen_seek_next_packet(wtap *wth, int *err, gchar **err_info,
char *hdr)
{
gint64 cur_off;
char buf[NETSCREEN_LINE_LENGTH];
while (1) {
cur_off = file_tell(wth->fh);
if (cur_off == -1) {
/* Error */
*err = file_error(wth->fh, err_info);
return -1;
}
if (file_gets(buf, sizeof(buf), wth->fh) == NULL) {
/* EOF or error. */
*err = file_error(wth->fh, err_info);
break;
}
if (strstr(buf, NETSCREEN_REC_MAGIC_STR1) ||
strstr(buf, NETSCREEN_REC_MAGIC_STR2)) {
g_strlcpy(hdr, buf, NETSCREEN_LINE_LENGTH);
return cur_off;
}
}
return -1;
}
/* Look through the first part of a file to see if this is
* NetScreen snoop output.
*
* Returns TRUE if it is, FALSE if it isn't or if we get an I/O error;
* if we get an I/O error, "*err" will be set to a non-zero value and
* "*err_info" is set to null or an additional error string.
*/
static gboolean netscreen_check_file_type(wtap *wth, int *err, gchar **err_info)
{
char buf[NETSCREEN_LINE_LENGTH];
guint reclen, line;
buf[NETSCREEN_LINE_LENGTH-1] = '\0';
for (line = 0; line < NETSCREEN_HEADER_LINES_TO_CHECK; line++) {
if (file_gets(buf, NETSCREEN_LINE_LENGTH, wth->fh) == NULL) {
/* EOF or error. */
*err = file_error(wth->fh, err_info);
return FALSE;
}
reclen = (guint) strlen(buf);
if (reclen < strlen(NETSCREEN_HDR_MAGIC_STR1) ||
reclen < strlen(NETSCREEN_HDR_MAGIC_STR2)) {
continue;
}
if (strstr(buf, NETSCREEN_HDR_MAGIC_STR1) ||
strstr(buf, NETSCREEN_HDR_MAGIC_STR2)) {
return TRUE;
}
}
*err = 0;
return FALSE;
}
wtap_open_return_val netscreen_open(wtap *wth, int *err, gchar **err_info)
{
/* Look for a NetScreen snoop header line */
if (!netscreen_check_file_type(wth, err, err_info)) {
if (*err != 0 && *err != WTAP_ERR_SHORT_READ)
return WTAP_OPEN_ERROR;
return WTAP_OPEN_NOT_MINE;
}
if (file_seek(wth->fh, 0L, SEEK_SET, err) == -1) /* rewind */
return WTAP_OPEN_ERROR;
wth->file_encap = WTAP_ENCAP_UNKNOWN;
wth->file_type_subtype = WTAP_FILE_TYPE_SUBTYPE_NETSCREEN;
wth->snapshot_length = 0; /* not known */
wth->subtype_read = netscreen_read;
wth->subtype_seek_read = netscreen_seek_read;
wth->file_tsprec = WTAP_TSPREC_DSEC;
return WTAP_OPEN_MINE;
}
/* Find the next packet and parse it; called from wtap_read(). */
static gboolean netscreen_read(wtap *wth, int *err, gchar **err_info,
gint64 *data_offset)
{
gint64 offset;
char line[NETSCREEN_LINE_LENGTH];
/* Find the next packet */
offset = netscreen_seek_next_packet(wth, err, err_info, line);
if (offset < 0)
return FALSE;
/* Parse the header and convert the ASCII hex dump to binary data */
if (!parse_netscreen_packet(wth->fh, &wth->phdr,
wth->frame_buffer, line, err, err_info))
return FALSE;
/*
* If the per-file encapsulation isn't known, set it to this
* packet's encapsulation.
*
* If it *is* known, and it isn't this packet's encapsulation,
* set it to WTAP_ENCAP_PER_PACKET, as this file doesn't
* have a single encapsulation for all packets in the file.
*/
if (wth->file_encap == WTAP_ENCAP_UNKNOWN)
wth->file_encap = wth->phdr.pkt_encap;
else {
if (wth->file_encap != wth->phdr.pkt_encap)
wth->file_encap = WTAP_ENCAP_PER_PACKET;
}
*data_offset = offset;
return TRUE;
}
/* Used to read packets in random-access fashion */
static gboolean
netscreen_seek_read(wtap *wth, gint64 seek_off,
struct wtap_pkthdr *phdr, Buffer *buf,
int *err, gchar **err_info)
{
char line[NETSCREEN_LINE_LENGTH];
if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1) {
return FALSE;
}
if (file_gets(line, NETSCREEN_LINE_LENGTH, wth->random_fh) == NULL) {
*err = file_error(wth->random_fh, err_info);
if (*err == 0) {
*err = WTAP_ERR_SHORT_READ;
}
return FALSE;
}
return parse_netscreen_packet(wth->random_fh, phdr, buf, line,
err, err_info);
}
/* Parses a packet record header. There are a few possible formats:
*
* XXX list extra formats here!
6843828.0: trust(o) len=98:00121ebbd132->00600868d659/0800
192.168.1.1 -> 192.168.1.10/6
vhl=45, tos=00, id=37739, frag=0000, ttl=64 tlen=84
tcp:ports 2222->2333, seq=3452113890, ack=1540618280, flag=5018/ACK
00 60 08 68 d6 59 00 12 1e bb d1 32 08 00 45 00 .`.h.Y.....2..E.
00 54 93 6b 00 00 40 06 63 dd c0 a8 01 01 c0 a8 .T.k..@.c.......
01 0a 08 ae 09 1d cd c3 13 e2 5b d3 f8 28 50 18 ..........[..(P.
1f d4 79 21 00 00 e7 76 89 64 16 e2 19 0a 80 09 ..y!...v.d......
31 e7 04 28 04 58 f3 d9 b1 9f 3d 65 1a db d8 61 1..(.X....=e...a
2c 21 b6 d3 20 60 0c 8c 35 98 88 cf 20 91 0e a9 ,!...`..5.......
1d 0b ..
*/
static gboolean
parse_netscreen_packet(FILE_T fh, struct wtap_pkthdr *phdr, Buffer* buf,
char *line, int *err, gchar **err_info)
{
int pkt_len;
int sec;
int dsec;
char cap_int[NETSCREEN_MAX_INT_NAME_LENGTH];
char direction[2];
char cap_src[13];
char cap_dst[13];
guint8 *pd;
gchar *p;
int n, i = 0;
int offset = 0;
gchar dststr[13];
phdr->rec_type = REC_TYPE_PACKET;
phdr->presence_flags = WTAP_HAS_TS|WTAP_HAS_CAP_LEN;
if (sscanf(line, "%9d.%9d: %15[a-z0-9/:.-](%1[io]) len=%9d:%12s->%12s/",
&sec, &dsec, cap_int, direction, &pkt_len, cap_src, cap_dst) < 5) {
*err = WTAP_ERR_BAD_FILE;
*err_info = g_strdup("netscreen: Can't parse packet-header");
return -1;
}
if (pkt_len < 0) {
*err = WTAP_ERR_BAD_FILE;
*err_info = g_strdup("netscreen: packet header has a negative packet length");
return FALSE;
}
if (pkt_len > WTAP_MAX_PACKET_SIZE) {
/*
* Probably a corrupt capture file; don't blow up trying
* to allocate space for an immensely-large packet.
*/
*err = WTAP_ERR_BAD_FILE;
*err_info = g_strdup_printf("netscreen: File has %u-byte packet, bigger than maximum of %u",
pkt_len, WTAP_MAX_PACKET_SIZE);
return FALSE;
}
/*
* If direction[0] is 'o', the direction is NETSCREEN_EGRESS,
* otherwise it's NETSCREEN_INGRESS.
*/
phdr->ts.secs = sec;
phdr->ts.nsecs = dsec * 100000000;
phdr->len = pkt_len;
/* Make sure we have enough room for the packet */
ws_buffer_assure_space(buf, pkt_len);
pd = ws_buffer_start_ptr(buf);
while(1) {
/* The last packet is not delimited by an empty line, but by EOF
* So accept EOF as a valid delimiter too
*/
if (file_gets(line, NETSCREEN_LINE_LENGTH, fh) == NULL) {
break;
}
/*
* Skip blanks.
* The number of blanks is not fixed - for wireless
* interfaces, there may be 14 extra spaces before
* the hex data.
*/
for (p = &line[0]; g_ascii_isspace(*p); p++)
;
/* packets are delimited with empty lines */
if (*p == '\0') {
break;
}
n = parse_single_hex_dump_line(p, pd, offset);
/* the smallest packet has a length of 6 bytes, if
* the first hex-data is less then check whether
* it is a info-line and act accordingly
*/
if (offset == 0 && n < 6) {
if (info_line(line)) {
if (++i <= NETSCREEN_MAX_INFOLINES) {
continue;
}
} else {
*err = WTAP_ERR_BAD_FILE;
*err_info = g_strdup("netscreen: cannot parse hex-data");
return FALSE;
}
}
/* If there is no more data and the line was not empty,
* then there must be an error in the file
*/
if (n == -1) {
*err = WTAP_ERR_BAD_FILE;
*err_info = g_strdup("netscreen: cannot parse hex-data");
return FALSE;
}
/* Adjust the offset to the data that was just added to the buffer */
offset += n;
/* If there was more hex-data than was announced in the len=x
* header, then then there must be an error in the file
*/
if (offset > pkt_len) {
*err = WTAP_ERR_BAD_FILE;
*err_info = g_strdup("netscreen: too much hex-data");
return FALSE;
}
}
/*
* Determine the encapsulation type, based on the
* first 4 characters of the interface name
*
* XXX convert this to a 'case' structure when adding more
* (non-ethernet) interfacetypes
*/
if (strncmp(cap_int, "adsl", 4) == 0) {
/* The ADSL interface can be bridged with or without
* PPP encapsulation. Check whether the first six bytes
* of the hex data are the same as the destination mac
* address in the header. If they are, assume ethernet
* LinkLayer or else PPP
*/
g_snprintf(dststr, 13, "%02x%02x%02x%02x%02x%02x",
pd[0], pd[1], pd[2], pd[3], pd[4], pd[5]);
if (strncmp(dststr, cap_dst, 12) == 0)
phdr->pkt_encap = WTAP_ENCAP_ETHERNET;
else
phdr->pkt_encap = WTAP_ENCAP_PPP;
}
else if (strncmp(cap_int, "seri", 4) == 0)
phdr->pkt_encap = WTAP_ENCAP_PPP;
else
phdr->pkt_encap = WTAP_ENCAP_ETHERNET;
phdr->caplen = offset;
return TRUE;
}
/* Take a string representing one line from a hex dump, with leading white
* space removed, and converts the text to binary data. We place the bytes
* in the buffer at the specified offset.
*
* Returns number of bytes successfully read, -1 if bad. */
static int
parse_single_hex_dump_line(char* rec, guint8 *buf, guint byte_offset)
{
int num_items_scanned;
guint8 character;
guint8 byte;
for (num_items_scanned = 0; num_items_scanned < 16; num_items_scanned++) {
character = *rec++;
if (character >= '0' && character <= '9')
byte = character - '0' + 0;
else if (character >= 'A' && character <= 'F')
byte = character - 'A' + 0xA;
else if (character >= 'a' && character <= 'f')
byte = character - 'a' + 0xa;
else if (character == ' ' || character == '\r' || character == '\n' || character == '\0') {
/* Nothing more to parse */
break;
} else
return -1; /* not a hex digit, space before ASCII dump, or EOL */
byte <<= 4;
character = *rec++ & 0xFF;
if (character >= '0' && character <= '9')
byte += character - '0' + 0;
else if (character >= 'A' && character <= 'F')
byte += character - 'A' + 0xA;
else if (character >= 'a' && character <= 'f')
byte += character - 'a' + 0xa;
else
return -1; /* not a hex digit */
buf[byte_offset + num_items_scanned] = byte;
character = *rec++ & 0xFF;
if (character == '\0' || character == '\r' || character == '\n') {
/* Nothing more to parse */
break;
} else if (character != ' ') {
/* not space before ASCII dump */
return -1;
}
}
if (num_items_scanned == 0)
return -1;
return num_items_scanned;
}
/*
* Editor modelines - http://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 8
* tab-width: 8
* indent-tabs-mode: t
* End:
*
* vi: set shiftwidth=8 tabstop=8 noexpandtab:
* :indentSize=8:tabSize=8:noTabs=false:
*/