Below is the file 'policy.py' from this revision. You can also download the file.

#!/usr/bin/env python

from Crypto.Hash import MD5
import addrhash
import config
import sys

def log_rejection(req, reason):
    return
    print >>sys.stderr, req, reason

if __name__ == '__main__':
    # verify incoming email addresses; see if they're
    # trying to brute-force us, and log that. otherwise,
    # let the mail through and we'll log more about the
    # message on delivery to that script

    def check(req):
        if not req.has_key('recipient'):
            return "DUNNO"
        try:
            user = req['recipient']
            user_at = user.find('@')
            if user_at == -1:
                return "DUNNO"
            user = user[:user_at]
            addrhash.decode(user)
        except addrhash.GaisdeException, e:
            log_rejection(req, str(e))
            return "REJECT 450 User unknown."

        return "PREPEND X-Gaisde: HMAC-verified."

    req = {}
    while True:
        line = sys.stdin.readline()
        stripped = line.strip()
        if line == '' or stripped == '':
            try: response = check(req)
            except: response = "DUNNO"
            sys.stdout.write('action='+response+'\n\n')
	    sys.stdout.flush()
            req = {}
        if line == '':
            break
        if stripped:
            sp = line.split('=', 1)
            if len(sp) != 2:
                continue
            req[sp[0]] = sp[1]