Preliminary I2P Interface support

RNS/vendor/i2plib/sam.py

@@ -0,0 +1,147 @@
+from base64 import b64decode, b64encode, b32encode
+from hashlib import sha256
+import struct
+import re
+
+
+I2P_B64_CHARS = "-~"
+
+def i2p_b64encode(x):
+    """Encode I2P destination"""
+    return b64encode(x, altchars=I2P_B64_CHARS.encode()).decode() 
+
+def i2p_b64decode(x):
+    """Decode I2P destination"""
+    return b64decode(x, altchars=I2P_B64_CHARS, validate=True)
+
+SAM_BUFSIZE = 4096
+DEFAULT_ADDRESS = ("127.0.0.1", 7656)
+DEFAULT_MIN_VER = "3.1"
+DEFAULT_MAX_VER = "3.1"
+TRANSIENT_DESTINATION = "TRANSIENT"
+
+VALID_BASE32_ADDRESS = re.compile(r"^([a-zA-Z0-9]{52}).b32.i2p$")
+VALID_BASE64_ADDRESS = re.compile(r"^([a-zA-Z0-9-~=]{516,528})$")
+
+class Message(object):
+    """Parse SAM message to an object"""
+    def __init__(self, s):
+        self.opts = {}
+        if type(s) != str:
+            self._reply_string = s.decode().strip()
+        else:
+            self._reply_string = s
+
+        self.cmd, self.action, opts = self._reply_string.split(" ", 2)
+        for v in opts.split(" "):
+            data = v.split("=", 1) if "=" in v else (v, True)
+            self.opts[data[0]] = data[1]
+
+    def __getitem__(self, key):
+        return self.opts[key]
+
+    @property
+    def ok(self):
+        return self["RESULT"] == "OK"
+
+    def __repr__(self):
+        return self._reply_string
+
+
+# SAM request messages
+
+def hello(min_version, max_version):
+    return "HELLO VERSION MIN={} MAX={}\n".format(min_version, 
+            max_version).encode()
+
+def session_create(style, session_id, destination, options=""):
+    return "SESSION CREATE STYLE={} ID={} DESTINATION={} {}\n".format(
+            style, session_id, destination, options).encode()
+
+
+def stream_connect(session_id, destination, silent="false"):
+    return "STREAM CONNECT ID={} DESTINATION={} SILENT={}\n".format(
+            session_id, destination, silent).encode()
+
+def stream_accept(session_id, silent="false"):
+    return "STREAM ACCEPT ID={} SILENT={}\n".format(session_id, silent).encode()
+
+def stream_forward(session_id, port, options=""):
+    return "STREAM FORWARD ID={} PORT={} {}\n".format(
+            session_id, port, options).encode()
+
+
+
+def naming_lookup(name):
+    return "NAMING LOOKUP NAME={}\n".format(name).encode()
+
+def dest_generate(signature_type):
+    return "DEST GENERATE SIGNATURE_TYPE={}\n".format(signature_type).encode()
+
+class Destination(object):
+    """I2P destination
+
+    https://geti2p.net/spec/common-structures#destination
+
+    :param data: (optional) Base64 encoded data or binary data 
+    :param path: (optional) A path to a file with binary data 
+    :param has_private_key: (optional) Does data have a private key? 
+    """
+
+    ECDSA_SHA256_P256 = 1
+    ECDSA_SHA384_P384 = 2
+    ECDSA_SHA512_P521 = 3
+    EdDSA_SHA512_Ed25519 = 7
+
+    default_sig_type = EdDSA_SHA512_Ed25519
+
+    _pubkey_size = 256
+    _signkey_size = 128
+    _min_cert_size = 3
+
+    def __init__(self, data=None, path=None, has_private_key=False):
+        #: Binary destination
+        self.data = bytes() 
+        #: Base64 encoded destination
+        self.base64 = ""    
+        #: :class:`RNS.vendor.i2plib.PrivateKey` instance or None
+        self.private_key = None    
+        
+        if path:
+            with open(path, "rb") as f: data = f.read()
+
+        if data and has_private_key:
+            self.private_key = PrivateKey(data)
+
+            cert_len = struct.unpack("!H", self.private_key.data[385:387])[0]
+            data = self.private_key.data[:387+cert_len]
+
+        if not data:
+            raise Exception("Can't create a destination with no data")
+
+        self.data = data if type(data) == bytes else i2p_b64decode(data)
+        self.base64 = data if type(data) == str else i2p_b64encode(data)
+
+    def __repr__(self):
+        return "<Destination: {}>".format(self.base32)
+
+    @property
+    def base32(self):
+        """Base32 destination hash of this destination"""
+        desthash = sha256(self.data).digest()
+        return b32encode(desthash).decode()[:52].lower()
+    
+class PrivateKey(object):
+    """I2P private key
+
+    https://geti2p.net/spec/common-structures#keysandcert
+
+    :param data: Base64 encoded data or binary data 
+    """
+
+    def __init__(self, data):
+        #: Binary private key
+        self.data = data if type(data) == bytes else i2p_b64decode(data)
+        #: Base64 encoded private key
+        self.base64 = data if type(data) == str else i2p_b64encode(data)
+