1
0
mirror of https://github.com/GNS3/gns3-server synced 2024-12-04 22:28:12 +00:00
gns3-server/gns3server/compute/iou/utils/iou_export.py

234 lines
7.1 KiB
Python
Raw Normal View History

2015-06-06 21:15:03 +00:00
#!/usr/bin/env python3
# To use python v2.7 change the first line to:
#!/usr/bin/env python
# Copyright (C) 2015 Bernhard Ehlers
#
# 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, see <http://www.gnu.org/licenses/>.
# This utility is a stripped down version of dynamips' nvram_export,
# ported from C to Python, see https://github.com/GNS3/dynamips
# nvram_export is (c) 2013 Flávio J. Saraiva
"""
iou_export exports startup/private configuration from IOU NVRAM file.
usage: iou_export [-h] NVRAM startup-config [private-config]
positional arguments:
NVRAM NVRAM file
startup-config startup configuration
private-config private configuration
optional arguments:
-h, --help show this help message and exit
"""
2020-07-17 12:07:25 +00:00
import struct
2015-06-06 21:15:03 +00:00
2020-07-17 12:07:25 +00:00
# Uncompress data in LZC format, .Z file format
# LZC uses the LZW compression algorithm with a variable dictionary size
# For LZW see https://en.wikipedia.org/wiki/LempelZivWelch
# Performance: about 1 MByte/sec, 15-50 times slower than C implementation
2015-06-06 21:15:03 +00:00
def uncompress_LZC(data):
LZC_NUM_BITS_MIN = 9
LZC_NUM_BITS_MAX = 16
2021-04-13 09:16:50 +00:00
in_data = bytearray(data)
in_len = len(in_data)
out_data = bytearray()
2015-06-06 21:15:03 +00:00
if in_len == 0:
return out_data
2015-06-06 21:15:03 +00:00
if in_len < 3:
2021-04-13 09:16:50 +00:00
raise ValueError("invalid length")
2015-06-06 21:15:03 +00:00
if in_data[0] != 0x1F or in_data[1] != 0x9D:
2021-04-13 09:16:50 +00:00
raise ValueError("invalid header")
2015-06-06 21:15:03 +00:00
2020-07-17 12:07:25 +00:00
max_bits = in_data[2] & 0x1F
if max_bits < LZC_NUM_BITS_MIN or max_bits > LZC_NUM_BITS_MAX:
2021-04-13 09:16:50 +00:00
raise ValueError("not supported")
2020-07-17 12:07:25 +00:00
num_items = 1 << max_bits
blockmode = (in_data[2] & 0x80) != 0
2021-04-13 09:16:50 +00:00
in_pos = 3
2020-07-17 12:07:25 +00:00
start_pos = in_pos
2021-04-13 09:16:50 +00:00
num_bits = LZC_NUM_BITS_MIN
2020-07-17 12:07:25 +00:00
dict_size = 1 << num_bits
2021-04-13 09:16:50 +00:00
head = 256
2020-07-17 12:07:25 +00:00
if blockmode:
2015-06-06 21:15:03 +00:00
head += 1
2020-07-17 12:07:25 +00:00
first_sym = True
# initialize dictionary
comp_dict = [None] * num_items
for i in range(0, 256):
comp_dict[i] = bytes(bytearray([i]))
2015-06-06 21:15:03 +00:00
2020-07-17 12:07:25 +00:00
buf = buf_bits = 0
while in_pos < in_len:
# get next symbol
try:
while buf_bits < num_bits:
buf |= in_data[in_pos] << buf_bits
buf_bits += 8
in_pos += 1
buf, symbol = divmod(buf, dict_size)
buf_bits -= num_bits
except IndexError:
2021-04-13 09:16:50 +00:00
raise ValueError("invalid data")
2020-07-17 12:07:25 +00:00
# re-initialize dictionary
if blockmode and symbol == 256:
# skip to next buffer boundary
buf = buf_bits = 0
in_pos += (start_pos - in_pos) % num_bits
# reset to LZC_NUM_BITS_MIN
2015-06-06 21:15:03 +00:00
head = 257
2020-07-17 12:07:25 +00:00
num_bits = LZC_NUM_BITS_MIN
dict_size = 1 << num_bits
start_pos = in_pos
first_sym = True
2015-06-06 21:15:03 +00:00
continue
2020-07-17 12:07:25 +00:00
# first symbol
if first_sym:
first_sym = False
if symbol >= 256:
2021-04-13 09:16:50 +00:00
raise ValueError("invalid data")
2020-07-17 12:07:25 +00:00
prev = symbol
out_data.extend(comp_dict[symbol])
continue
2015-06-06 21:15:03 +00:00
2020-07-17 12:07:25 +00:00
# dictionary full
if head >= num_items:
out_data.extend(comp_dict[symbol])
continue
2015-06-06 21:15:03 +00:00
2020-07-17 12:07:25 +00:00
# update compression dictionary
if symbol < head:
comp_dict[head] = comp_dict[prev] + comp_dict[symbol][0:1]
elif symbol == head:
comp_dict[head] = comp_dict[prev] + comp_dict[prev][0:1]
else:
2021-04-13 09:16:50 +00:00
raise ValueError("invalid data")
2020-07-17 12:07:25 +00:00
prev = symbol
2015-06-06 21:15:03 +00:00
2020-07-17 12:07:25 +00:00
# output symbol
out_data.extend(comp_dict[symbol])
2015-06-06 21:15:03 +00:00
2020-07-17 12:07:25 +00:00
# update head, check for num_bits change
head += 1
if head >= dict_size and num_bits < max_bits:
num_bits += 1
dict_size = 1 << num_bits
start_pos = in_pos
2015-06-06 21:15:03 +00:00
2020-07-17 12:07:25 +00:00
return out_data
2015-06-06 21:15:03 +00:00
# export IOU NVRAM
2020-07-17 12:07:25 +00:00
# NVRAM format: https://github.com/ehlers/IOUtools/blob/master/NVRAM.md
2015-06-06 21:15:03 +00:00
def nvram_export(nvram):
nvram = bytearray(nvram)
2015-06-06 21:15:03 +00:00
offset = 0
2020-07-17 12:07:25 +00:00
# extract startup config
try:
2021-04-13 09:16:50 +00:00
(magic, data_format, _, _, _, _, length, _, _, _, _, _) = struct.unpack_from(
">HHHHIIIIIHHI", nvram, offset=offset
)
2020-07-17 12:07:25 +00:00
offset += 36
if magic != 0xABCD:
2021-04-13 09:16:50 +00:00
raise ValueError("no startup config")
if len(nvram) < offset + length:
raise ValueError("invalid length")
startup = nvram[offset : offset + length]
2020-07-17 12:07:25 +00:00
except struct.error:
2021-04-13 09:16:50 +00:00
raise ValueError("invalid length")
2015-06-06 21:15:03 +00:00
2020-07-17 12:07:25 +00:00
# uncompress startup config
if data_format == 2:
2015-06-06 21:15:03 +00:00
try:
startup = uncompress_LZC(startup)
except ValueError as err:
2021-04-13 09:16:50 +00:00
raise ValueError("uncompress startup: " + str(err))
2015-06-06 21:15:03 +00:00
private = None
2020-07-17 12:07:25 +00:00
try:
# calculate offset of private header
2021-04-13 09:16:50 +00:00
length += (4 - length % 4) % 4 # alignment to multiple of 4
2020-07-17 12:07:25 +00:00
offset += length
# check for additonal offset of 4
2021-04-13 09:16:50 +00:00
(magic, data_format) = struct.unpack_from(">HH", nvram, offset=offset + 4)
2020-07-17 12:07:25 +00:00
if magic == 0xFEDC and data_format == 1:
offset += 4
# extract private config
2021-04-13 09:16:50 +00:00
(magic, data_format, _, _, length) = struct.unpack_from(">HHIII", nvram, offset=offset)
2015-06-06 21:15:03 +00:00
offset += 16
2020-07-17 12:07:25 +00:00
if magic == 0xFEDC and data_format == 1:
2021-04-13 09:16:50 +00:00
if len(nvram) < offset + length:
raise ValueError("invalid length")
private = nvram[offset : offset + length]
2020-07-17 12:07:25 +00:00
# missing private header is not an error
except struct.error:
pass
2015-06-06 21:15:03 +00:00
return (startup, private)
2021-04-13 09:16:50 +00:00
if __name__ == "__main__":
2015-06-06 21:15:03 +00:00
# Main program
2020-07-17 12:07:25 +00:00
import argparse
import sys
2015-06-06 21:15:03 +00:00
2021-04-13 09:16:50 +00:00
parser = argparse.ArgumentParser(description="%(prog)s exports startup/private configuration from IOU NVRAM file.")
parser.add_argument("nvram", metavar="NVRAM", help="NVRAM file")
parser.add_argument("startup", metavar="startup-config", help="startup configuration")
parser.add_argument("private", metavar="private-config", nargs="?", help="private configuration")
2015-06-06 21:15:03 +00:00
args = parser.parse_args()
try:
2021-04-13 09:16:50 +00:00
fd = open(args.nvram, "rb")
2015-06-06 21:15:03 +00:00
nvram = fd.read()
fd.close()
2021-04-13 09:07:58 +00:00
except OSError as err:
sys.stderr.write(f"Error reading file: {err}\n")
2015-06-06 21:15:03 +00:00
sys.exit(1)
try:
startup, private = nvram_export(nvram)
except ValueError as err:
2021-04-13 09:07:58 +00:00
sys.stderr.write(f"nvram_export: {err}\n")
2015-06-06 21:15:03 +00:00
sys.exit(3)
try:
2021-04-13 09:16:50 +00:00
fd = open(args.startup, "wb")
2015-06-06 21:15:03 +00:00
fd.write(startup)
fd.close()
if args.private is not None:
if private is None:
sys.stderr.write("Warning: No private config\n")
else:
2021-04-13 09:16:50 +00:00
fd = open(args.private, "wb")
2015-06-06 21:15:03 +00:00
fd.write(private)
fd.close()
2021-04-13 09:07:58 +00:00
except OSError as err:
sys.stderr.write(f"Error writing file: {err}\n")
2015-06-06 21:15:03 +00:00
sys.exit(1)