lnbase: implement key rotation, request initial sync in localfeatures

lib/lnbase.py

@@ -309,6 +309,7 @@ class Peer(PrintError):
         self.temporary_channel_id_to_incoming_accept_channel = {}
         self.temporary_channel_id_to_incoming_funding_signed = {}
         self.init_message_received_future = asyncio.Future()
+        self.localfeatures = 0x08 # request initial sync
 
     def diagnostic_name(self):
         return self.host
@@ -322,26 +323,29 @@ class Peer(PrintError):
         message_type, payload = decode_msg(msg)
         self.print_error("Sending '%s'"%message_type.upper(), payload)
         l = encode(len(msg), 2)
-        lc = aead_encrypt(self.sk, self.sn, b'', l)
-        c = aead_encrypt(self.sk, self.sn+1, b'', msg)
+        lc = aead_encrypt(self.sk, self.sn(), b'', l)
+        c = aead_encrypt(self.sk, self.sn(), b'', msg)
         assert len(lc) == 18
         assert len(c) == len(msg) + 16
         self.writer.write(lc+c)
-        self.sn += 2
 
     async def read_message(self):
         while True:
-            self.read_buffer += await self.reader.read(2**10)
+            s = await self.reader.read(2**10)
+            if not s:
+                raise Exception('connection closed')
+            self.read_buffer += s
+            if len(self.read_buffer) < 18:
+                continue
             lc = self.read_buffer[:18]
-            l = aead_decrypt(self.rk, self.rn, b'', lc)
+            l = aead_decrypt(self.rk, self.rn(), b'', lc)
             length = int.from_bytes(l, byteorder="big")
             offset = 18 + length + 16
             if len(self.read_buffer) < offset:
                 continue
             c = self.read_buffer[18:offset]
             self.read_buffer = self.read_buffer[offset:]
-            msg = aead_decrypt(self.rk, self.rn+1, b'', c)
-            self.rn += 2
+            msg = aead_decrypt(self.rk, self.rn(), b'', c)
             return msg
 
     async def handshake(self):
@@ -373,8 +377,26 @@ class Peer(PrintError):
         msg = hs.handshake_version + c + t
         self.writer.write(msg)
         # init counters
-        self.sn = 0
-        self.rn = 0
+        self._sn = 0
+        self._rn = 0
+        self.r_ck = ck
+        self.s_ck = ck
+
+    def rn(self):
+        o = self._rn
+        self._rn += 1
+        if self._rn == 1000:
+            self.r_ck, self.rk = get_bolt8_hkdf(self.r_ck, self.rk)
+            self._rn = 0
+        return o
+
+    def sn(self):
+        o = self._sn
+        self._sn += 1
+        if self._sn == 1000:
+            self.s_ck, self.sk = get_bolt8_hkdf(self.s_ck, self.sk)
+            self._sn = 0
+        return o
 
     def process_message(self, message):
         message_type, payload = decode_msg(message)
@@ -458,7 +480,7 @@ class Peer(PrintError):
         self.reader, self.writer = await asyncio.open_connection(self.host, self.port)
         await self.handshake()
         # send init
-        self.send_message(gen_msg("init", gflen=0, lflen=0))
+        self.send_message(gen_msg("init", gflen=0, lflen=1, localfeatures=self.localfeatures))
         # read init
         msg = await self.read_message()
         self.process_message(msg)