splinext/gts/controllers/gts.py

   1 # encoding: utf8
   2 from __future__ import absolute_import, division
   3
   4 from base64 import urlsafe_b64decode
   5 from collections import namedtuple
   6 from itertools import izip
   7 import logging
   8 from random import sample
   9 from string import uppercase, lowercase, digits
  10 import struct
  11
  12 import pokedex.db
  13 import pokedex.db.tables as tables
  14 import pokedex.formulae
  15 from pokedex.struct import SaveFilePokemon
  16 from pylons import config, request, response, session, tmpl_context as c, url
  17 from pylons.controllers.util import abort, redirect_to
  18 from sqlalchemy import and_, or_, not_
  19 from sqlalchemy.orm import aliased, contains_eager, eagerload, eagerload_all, join
  20 from sqlalchemy.orm.exc import NoResultFound
  21 from sqlalchemy.sql import func
  22
  23 from spline.model import meta
  24 from spline.lib.base import BaseController, render
  25 from spline.lib import helpers as h
  26 from splinext.gts import model as gts_model
  27
  28 log = logging.getLogger(__name__)
  29
  30
  31 ### Utility functions
  32
  33 def gts_prng(seed):
  34     """Implements the GTS's linear congruential generator.
  35
  36     I love typing that out.  It makes me sounds so smart.
  37
  38     Yields magical numbers."""
  39     # 0xabcd => 0xabcdabcd
  40     seed = seed | (seed << 16)
  41     while True:
  42         seed = (seed * 0x45 + 0x1111) & 0x7fffffff  # signed dword!
  43         yield (seed >> 16) & 0xff
  44
  45 def stream_decipher(data, keystream):
  46     """Reverses a stream cipher, given iterable data and keystream.
  47
  48     Yields decrypted bytes.
  49     """
  50     for c, key in izip(data, keystream):
  51         new_c = (ord(c) ^ key) & 0xff
  52         yield chr(new_c)
  53
  54
  55 def decrypt_data(data):
  56     """Takes a binary blob uploaded from a game and returns the original binary
  57     blob.  Depending on your perspective, the returned value may be more
  58     intelligible.
  59     """
  60     # GTS encryption is a simple stream cipher.
  61     # The first four bytes of the data are a header containing an obfuscated
  62     # key; the rest is the message
  63     obf_key_blob, message = data[0:4], data[4:]
  64     obf_key, = struct.unpack('>I', obf_key_blob)
  65     key = obf_key ^ 0x4a3b2c1d
  66
  67     # Data is XORed with the output of an LCG, like everything else in Pokémon
  68     return ''.join( stream_decipher(message, gts_prng(key)) )
  69
  70
  71 ### Controller!
  72
  73 def dbg(*args):
  74     #print ' '.join(args)
  75     pass
  76
  77 class GTSController(BaseController):
  78
  79     def dispatch(self, page):
  80         """We do our own dispatching for two reasons:
  81
  82         1. All requests do challenge/response before anything, and it's easier
  83         to do that and then dispatch than copy/paste some block of code to
  84         every action.
  85
  86         2. Easier to dump stuff if desired.
  87         """
  88
  89         dbg(request)
  90
  91         # Always return binary!
  92         response.headers['Content-type'] = 'application/octet-stream'
  93
  94         if 'hash' in request.params:
  95             # Okay, already done the response.  Decrypt, then dispatch!
  96             if request.params['data']:
  97                 # Note: base64 doesn't like unicode.  Go figure.  It's binary
  98                 # junk, anyway.
  99                 encrypted_data = urlsafe_b64decode(str(request.params['data']))
 100                 data = decrypt_data(encrypted_data)
 101                 data = data[4:]  # data always starts with pid; we don't care
 102             else:
 103                 data = ''
 104
 105             method = 'page_' + page
 106             if not hasattr(self, method):
 107                 dbg("NOT YET IMPLEMENTED?")
 108                 abort(404)
 109
 110             res = getattr(self, method)(request.params['pid'], data)
 111             dbg("RESPONDING WITH ", type(res), len(res), repr(res))
 112             return res
 113
 114         # No hash.  Need to issue a challenge.  It's random, so whatever
 115         return ''.join(sample( uppercase + lowercase + digits, 32 ))
 116
 117     ### Actual pages
 118
 119     def page_info(self, pid, data):
 120         """info.asp
 121
 122         Apparently always returns 0x0001.  Probably just a ping to see if the
 123         server is up.
 124         """
 125
 126         return '\x01\x00'
 127
 128     def page_setProfile(self, pid, data):
 129         """setProfile.asp
 130
 131         Only Pt and later check this page.  Don't know why.  It returns eight
 132         NULs, every time.
 133         """
 134
 135         return '\x00' * 8
 136
 137     def page_result(self, pid, data):
 138         u"""result.asp
 139
 140         The good part!
 141
 142         This checks the game's status on the GTS.  If there's nothing
 143         interesting to report, it returns 0x0005.  If the game has a Pokémon up
 144         on the GTS, it returns 0x0004.
 145
 146         However...  if the game has a Pokémon waiting to come to it, it returns
 147         that entire Pokémon struct!  No header, no encryption.  Just a regular
 148         ol' Pokémon blob.
 149         """
 150
 151         # Check for an existing Pokémon
 152         # TODO support multiple!
 153         try:
 154             stored_pokemon = meta.Session.query(gts_model.GTSPokemon) \
 155                 .filter_by(pid=pid) \
 156                 .one()
 157             # We've got one!  Cool, send it back.  The game will ask us to
 158             # delete it after receiving successfully
 159             pokemon_save = SaveFilePokemon(stored_pokemon.pokemon_blob)
 160             return pokemon_save.as_encrypted
 161
 162         except:
 163             # Nothing
 164             return '\x05\x00'
 165
 166     def page_delete(self, pid, data):
 167         u"""delete.asp
 168
 169         If a Pokémon is received from result.asp, the game requests this page
 170         to confirm that the incoming Pokémon may be deleted.
 171
 172         Returns 0x0001.
 173         """
 174
 175         meta.Session.query(gts_model.GTSPokemon).filter_by(pid=pid).delete()
 176         meta.Session.commit()
 177
 178         return '\x01\x00'
 179
 180     def page_post(self, pid, data):
 181         u"""post.asp
 182
 183         Deposits a Pokémon in the GTS.  Returns 0x0001 on success, or 0x000c if
 184         the deposit is rejected.
 185         """
 186
 187         try:
 188             # The uploaded Pokémon is encrypted, which is not very useful
 189             pokemon_save = SaveFilePokemon(data, encrypted=True)
 190
 191             # Create a record...
 192             stored_pokemon = gts_model.GTSPokemon(
 193                 pid=pid,
 194                 pokemon_blob=pokemon_save.as_struct,
 195             )
 196             meta.Session.add(stored_pokemon)
 197             meta.Session.commit()
 198             return '\x01\x00'
 199         except:
 200             # If that failed (presumably due to unique key collision), we're
 201             # already storing something.  Reject!
 202             return '\x0c\x00'
 203
 204     def page_post_finish(self, pid, data):
 205         u"""post_finish.asp
 206
 207         Surely this does something, but for the life of me I can't figure out
 208         what.
 209
 210         Returns 0x0001.
 211         """
 212         return '\x01\x00'