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.savefile import PokemonSave
  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 import model
  24 from spline.model import meta
  25 from spline.lib.base import BaseController, render
  26 from spline.lib import helpers as h
  27
  28 from splinext.gts.model import GTSPokemon
  29
  30 log = logging.getLogger(__name__)
  31
  32
  33 ### Utility functions
  34
  35 def gts_prng(seed):
  36     """Implements the GTS's linear congruential generator.
  37
  38     I love typing that out.  It makes me sounds so smart.
  39
  40     Yields magical numbers."""
  41     # 0xabcd => 0xabcdabcd
  42     seed = seed | (seed << 16)
  43     while True:
  44         seed = (seed * 0x45 + 0x1111) & 0x7fffffff  # signed dword!
  45         yield (seed >> 16) & 0xff
  46
  47 def stream_decipher(data, keystream):
  48     """Reverses a stream cipher, given iterable data and keystream.
  49
  50     Yields decrypted bytes.
  51     """
  52     for c, key in izip(data, keystream):
  53         new_c = (ord(c) ^ key) & 0xff
  54         yield chr(new_c)
  55
  56
  57 def decrypt_data(data):
  58     """Takes a binary blob uploaded from a game and returns the original binary
  59     blob.  Depending on your perspective, the returned value may be more
  60     intelligible.
  61     """
  62     # GTS encryption is a simple stream cipher.
  63     # The first four bytes of the data are a header containing an obfuscated
  64     # key; the rest is the message
  65     obf_key_blob, message = data[0:4], data[4:]
  66     obf_key, = struct.unpack('>I', obf_key_blob)
  67     key = obf_key ^ 0x4a3b2c1d
  68
  69     # Data is XORed with the output of an LCG, like everything else in Pokémon
  70     return ''.join( stream_decipher(message, gts_prng(key)) )
  71
  72
  73 ### Controller!
  74
  75 def dbg(*args):
  76     #print ' '.join(args)
  77     pass
  78
  79 class GTSController(BaseController):
  80
  81     def dispatch(self, page):
  82         """We do our own dispatching for two reasons:
  83
  84         1. All requests do challenge/response before anything, and it's easier
  85         to do that and then dispatch than copy/paste some block of code to
  86         every action.
  87
  88         2. Easier to dump stuff if desired.
  89         """
  90
  91         dbg(request)
  92
  93         # Always return binary!
  94         response.headers['Content-type'] = 'application/octet-stream'
  95
  96         if 'hash' in request.params:
  97             # Okay, already done the response.  Decrypt, then dispatch!
  98             if request.params['data']:
  99                 # Note: base64 doesn't like unicode.  Go figure.  It's binary
 100                 # junk, anyway.
 101                 encrypted_data = urlsafe_b64decode(str(request.params['data']))
 102                 data = decrypt_data(encrypted_data)
 103                 data = data[4:]  # data always starts with pid; we don't care
 104             else:
 105                 data = ''
 106
 107             method = 'page_' + page
 108             if not hasattr(self, method):
 109                 dbg("NOT YET IMPLEMENTED?")
 110                 abort(404)
 111
 112             res = getattr(self, method)(request.params['pid'], data)
 113             dbg("RESPONDING WITH ", type(res), len(res), repr(res))
 114             return res
 115
 116         # No hash.  Need to issue a challenge.  It's random, so whatever
 117         return ''.join(sample( uppercase + lowercase + digits, 32 ))
 118
 119     ### Actual pages
 120
 121     def page_info(self, pid, data):
 122         """info.asp
 123
 124         Apparently always returns 0x0001.  Probably just a ping to see if the
 125         server is up.
 126         """
 127
 128         return '\x01\x00'
 129
 130     def page_setProfile(self, pid, data):
 131         """setProfile.asp
 132
 133         Only Pt and later check this page.  Don't know why.  It returns eight
 134         NULs, every time.
 135         """
 136
 137         return '\x00' * 8
 138
 139     def page_result(self, pid, data):
 140         u"""result.asp
 141
 142         The good part!
 143
 144         This checks the game's status on the GTS.  If there's nothing
 145         interesting to report, it returns 0x0005.  If the game has a Pokémon up
 146         on the GTS, it returns 0x0004.
 147
 148         However...  if the game has a Pokémon waiting to come to it, it returns
 149         that entire Pokémon struct!  No header, no encryption.  Just a regular
 150         ol' Pokémon blob.
 151         """
 152
 153         # Check for an existing Pokémon
 154         # TODO support multiple!
 155         try:
 156             stored_pokemon = meta.Session.query(model.GTSPokemon) \
 157                 .filter_by(pid=pid) \
 158                 .one()
 159             # We've got one!  Cool, send it back.  The game will ask us to
 160             # delete it after receiving successfully
 161             pokemon_save = PokemonSave(stored_pokemon.pokemon_blob)
 162             return pokemon_save.as_encrypted
 163
 164         except:
 165             # Nothing
 166             return '\x05\x00'
 167
 168     def page_delete(self, pid, data):
 169         u"""delete.asp
 170
 171         If a Pokémon is received from result.asp, the game requests this page
 172         to confirm that the incoming Pokémon may be deleted.
 173
 174         Returns 0x0001.
 175         """
 176
 177         meta.Session.query(model.GTSPokemon).filter_by(pid=pid).delete()
 178         meta.Session.commit()
 179
 180         return '\x01\x00'
 181
 182     def page_post(self, pid, data):
 183         u"""post.asp
 184
 185         Deposits a Pokémon in the GTS.  Returns 0x0001 on success, or 0x000c if
 186         the deposit is rejected.
 187         """
 188
 189         try:
 190             # The uploaded Pokémon is encrypted, which is not very useful
 191             pokemon_save = PokemonSave(data, encrypted=True)
 192
 193             # Create a record...
 194             stored_pokemon = model.GTSPokemon(
 195                 pid=pid,
 196                 pokemon_blob=pokemon_save.as_struct,
 197             )
 198             meta.Session.add(stored_pokemon)
 199             meta.Session.commit()
 200             return '\x01\x00'
 201         except:
 202             # If that failed (presumably due to unique key collision), we're
 203             # already storing something.  Reject!
 204             return '\x0c\x00'
 205
 206     def page_post_finish(self, pid, data):
 207         u"""post_finish.asp
 208
 209         Surely this does something, but for the life of me I can't figure out
 210         what.
 211
 212         Returns 0x0001.
 213         """
 214         return '\x01\x00'