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gns3-server/gns3server/hypervisor/iou/utils/iou_import.py
2016-03-08 16:12:46 +01:00

246 lines
8.0 KiB
Python

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# 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/>.
"""
iou_import imports startup/private configuration into IOU NVRAM file.
usage: iou_import [-h] [-c size] 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
-c size, --create size
create NVRAM file, size in kByte
"""
import argparse
import sys
# extract 16 bit unsigned int from data
def get_uint16(data, off):
return data[off] << 8 | data[off + 1]
# extract 32 bit unsigned int from data
def get_uint32(data, off):
return data[off] << 24 | data[off + 1] << 16 | data[off + 2] << 8 | data[off + 3]
# insert 16 bit unsigned int into data
def put_uint16(data, off, value):
data[off] = (value >> 8) & 0xff
data[off + 1] = value & 0xff
# insert 32 bit unsigned int into data
def put_uint32(data, off, value):
data[off] = (value >> 24) & 0xff
data[off + 1] = (value >> 16) & 0xff
data[off + 2] = (value >> 8) & 0xff
data[off + 3] = value & 0xff
# calculate padding
def padding(off, ios):
pad = (4 - off % 4) % 4 # padding to alignment of 4
if ios <= 0x0F00 and pad != 0: # add 4 if IOS <= 15.0
pad += 4
return pad
# update checksum
def checksum(data, start, end):
put_uint16(data, start + 4, 0) # set checksum to 0
chk = 0
idx = start
while idx < end - 1:
chk += get_uint16(data, idx)
idx += 2
if idx < end:
chk += data[idx] << 8
while chk >> 16:
chk = (chk & 0xffff) + (chk >> 16)
chk = chk ^ 0xffff
put_uint16(data, start + 4, chk) # set checksum
# import IOU NVRAM
def nvram_import(nvram, startup, private, size):
BASE_ADDRESS = 0x10000000
DEFAULT_IOS = 0x0F04 # IOS 15.4
# check size parameter
if size is not None and (size < 8 or size > 1024):
raise ValueError('invalid size')
# create new nvram if nvram is empty or has wrong size
if nvram is None or (size is not None and len(nvram) != size * 1024):
nvram = bytearray([0] * (size * 1024))
else:
nvram = bytearray(nvram)
# check nvram size
nvram_len = len(nvram)
if nvram_len < 8 * 1024 or nvram_len > 1024 * 1024 or nvram_len % 1024 != 0:
raise ValueError('invalid NVRAM length')
nvram_len = nvram_len // 2
# get size of current config
config_len = 0
ios = None
try:
if get_uint16(nvram, 0) == 0xABCD:
ios = get_uint16(nvram, 6)
config_len = 36 + get_uint32(nvram, 16)
config_len += padding(config_len, ios)
if get_uint16(nvram, config_len) == 0xFEDC:
config_len += 16 + get_uint32(nvram, config_len + 12)
except IndexError:
raise ValueError('unknown nvram format')
if config_len > nvram_len:
raise ValueError('unknown nvram format')
# calculate max. config size
max_config = nvram_len - 2 * 1024 # reserve 2k for files
idx = max_config
empty_sector = bytearray([0] * 1024)
while True:
idx -= 1024
if idx < config_len:
break
# if valid file header:
if get_uint16(nvram, idx + 0) == 0xDCBA and \
get_uint16(nvram, idx + 4) < 8 and \
get_uint16(nvram, idx + 6) <= 992:
max_config = idx
elif nvram[idx:idx + 1024] != empty_sector:
break
# import startup config
startup = bytearray(startup)
if ios is None:
# Target IOS version is unknown. As some IOU don't work nicely with
# the padding of a different version, the startup config is padded
# with '\n' to the alignment of 4.
ios = DEFAULT_IOS
startup.extend([ord('\n')] * ((4 - len(startup) % 4) % 4))
new_nvram = bytearray([0] * 36) # startup hdr
put_uint16(new_nvram, 0, 0xABCD) # magic
put_uint16(new_nvram, 2, 1) # raw data
put_uint16(new_nvram, 6, ios) # IOS version
put_uint32(new_nvram, 8, BASE_ADDRESS + 36) # start address
put_uint32(new_nvram, 12, BASE_ADDRESS + 36 + len(startup)) # end address
put_uint32(new_nvram, 16, len(startup)) # length
new_nvram.extend(startup)
new_nvram.extend([0] * padding(len(new_nvram), ios))
# import private config
if private is None:
private = bytearray()
else:
private = bytearray(private)
offset = len(new_nvram)
new_nvram.extend([0] * 16) # private hdr
put_uint16(new_nvram, 0 + offset, 0xFEDC) # magic
put_uint16(new_nvram, 2 + offset, 1) # raw data
put_uint32(new_nvram, 4 + offset,
BASE_ADDRESS + offset + 16) # start address
put_uint32(new_nvram, 8 + offset,
BASE_ADDRESS + offset + 16 + len(private)) # end address
put_uint32(new_nvram, 12 + offset, len(private)) # length
new_nvram.extend(private)
# add rest
if len(new_nvram) > max_config:
raise ValueError('NVRAM size too small')
new_nvram.extend([0] * (max_config - len(new_nvram)))
new_nvram.extend(nvram[max_config:])
checksum(new_nvram, 0, nvram_len)
return new_nvram
if __name__ == '__main__':
# Main program
def check_size(string):
try:
value = int(string)
except ValueError:
raise argparse.ArgumentTypeError('invalid int value: ' + string)
if value < 8 or value > 1024:
raise argparse.ArgumentTypeError('size must be 8..1024')
return value
parser = argparse.ArgumentParser(description='%(prog)s imports startup/private configuration into IOU NVRAM file.')
parser.add_argument('-c', '--create', metavar='size', type=check_size,
help='create NVRAM file, size in kByte')
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')
args = parser.parse_args()
try:
if args.create is None:
fd = open(args.nvram, 'rb')
nvram = fd.read()
fd.close()
else:
nvram = None
fd = open(args.startup, 'rb')
startup = fd.read()
fd.close()
if args.private is None:
private = None
else:
fd = open(args.private, 'rb')
private = fd.read()
fd.close()
except (IOError, OSError) as err:
sys.stderr.write("Error reading file: {}\n".format(err))
sys.exit(1)
try:
nvram = nvram_import(nvram, startup, private, args.create)
except ValueError as err:
sys.stderr.write("nvram_import: {}\n".format(err))
sys.exit(3)
try:
fd = open(args.nvram, 'wb')
fd.write(nvram)
fd.close()
except (IOError, OSError) as err:
sys.stderr.write("Error writing file: {}\n".format(err))
sys.exit(1)