#!/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 . # 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 """ import argparse import sys # Uncompress data in .Z file format. # Ported from dynamips' fs_nvram.c to python # Adapted from 7zip's ZDecoder.cpp, which is licensed under LGPL 2.1. def uncompress_LZC(data): LZC_NUM_BITS_MIN = 9 LZC_NUM_BITS_MAX = 16 in_data = bytearray(data) in_len = len(in_data) out_data = bytearray() if in_len == 0: return out_data if in_len < 3: raise ValueError('invalid length') if in_data[0] != 0x1F or in_data[1] != 0x9D: raise ValueError('invalid header') maxbits = in_data[2] & 0x1F numItems = 1 << maxbits blockMode = (in_data[2] & 0x80) != 0 if maxbits < LZC_NUM_BITS_MIN or maxbits > LZC_NUM_BITS_MAX: raise ValueError('not supported') parents = [0] * numItems suffixes = [0] * numItems in_pos = 3 numBits = LZC_NUM_BITS_MIN head = 256 if blockMode: head += 1 needPrev = 0 bitPos = 0 numBufBits = 0 parents[256] = 0 suffixes[256] = 0 buf_extend = bytearray([0] * 3) while True: # fill buffer, when empty if numBufBits == bitPos: buf_len = min(in_len - in_pos, numBits) buf = in_data[in_pos:in_pos + buf_len] + buf_extend numBufBits = buf_len << 3 bitPos = 0 in_pos += buf_len # extract next symbol bytePos = bitPos >> 3 symbol = buf[bytePos] | buf[bytePos + 1] << 8 | buf[bytePos + 2] << 16 symbol >>= bitPos & 7 symbol &= (1 << numBits) - 1 bitPos += numBits # check for special conditions: end, bad data, re-initialize dictionary if bitPos > numBufBits: break if symbol >= head: raise ValueError('invalid data') if blockMode and symbol == 256: numBufBits = bitPos = 0 numBits = LZC_NUM_BITS_MIN head = 257 needPrev = 0 continue # convert symbol to string stack = [] cur = symbol while cur >= 256: stack.append(suffixes[cur]) cur = parents[cur] stack.append(cur) if needPrev: suffixes[head - 1] = cur if symbol == head - 1: stack[0] = cur stack.reverse() out_data.extend(stack) # update parents, check for numBits change if head < numItems: needPrev = 1 parents[head] = symbol head += 1 if head > (1 << numBits): if numBits < maxbits: numBufBits = bitPos = 0 numBits += 1 else: needPrev = 0 return out_data # 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] # export IOU NVRAM def nvram_export(nvram): nvram = bytearray(nvram) # extract startup config offset = 0 if len(nvram) < offset + 36: raise ValueError('invalid length') if get_uint16(nvram, offset + 0) != 0xABCD: raise ValueError('no startup config') format = get_uint16(nvram, offset + 2) length = get_uint32(nvram, offset + 16) offset += 36 if len(nvram) < offset + length: raise ValueError('invalid length') startup = nvram[offset:offset + length] # compressed startup config if format == 2: try: startup = uncompress_LZC(startup) except ValueError as err: raise ValueError('uncompress startup: ' + str(err)) offset += length # alignment to multiple of 4 offset = (offset + 3) & ~3 # check for additonal offset of 4 if len(nvram) >= offset + 8 and \ get_uint16(nvram, offset + 4) == 0xFEDC and \ get_uint16(nvram, offset + 6) == 1: offset += 4 # extract private config private = None if len(nvram) >= offset + 16 and get_uint16(nvram, offset + 0) == 0xFEDC: length = get_uint32(nvram, offset + 12) offset += 16 if len(nvram) >= offset + length: private = nvram[offset:offset + length] return (startup, private) if __name__ == '__main__': # Main program 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') args = parser.parse_args() try: fd = open(args.nvram, 'rb') nvram = fd.read() fd.close() except (IOError, OSError) as err: sys.stderr.write("Error reading file: {}\n".format(err)) sys.exit(1) try: startup, private = nvram_export(nvram) except ValueError as err: sys.stderr.write("nvram_export: {}\n".format(err)) sys.exit(3) try: fd = open(args.startup, 'wb') fd.write(startup) fd.close() if args.private is not None: if private is None: sys.stderr.write("Warning: No private config\n") else: fd = open(args.private, 'wb') fd.write(private) fd.close() except (IOError, OSError) as err: sys.stderr.write("Error writing file: {}\n".format(err)) sys.exit(1)