144 lines
5.3 KiB
Python
144 lines
5.3 KiB
Python
import random
|
|
import asyncio
|
|
import logging
|
|
|
|
from rpcudp.protocol import RPCProtocol
|
|
|
|
from .node import Node
|
|
from .routing import RoutingTable
|
|
from .utils import digest
|
|
|
|
log = logging.getLogger(__name__) # pylint: disable=invalid-name
|
|
|
|
|
|
class KademliaProtocol(RPCProtocol):
|
|
"""
|
|
There are four main RPCs in the Kademlia protocol
|
|
PING, STORE, FIND_NODE, FIND_VALUE
|
|
PING probes if a node is still online
|
|
STORE instructs a node to store (key, value)
|
|
FIND_NODE takes a 160-bit ID and gets back
|
|
(ip, udp_port, node_id) for k closest nodes to target
|
|
FIND_VALUE behaves like FIND_NODE unless a value is stored
|
|
"""
|
|
def __init__(self, source_node, storage, ksize):
|
|
RPCProtocol.__init__(self)
|
|
self.router = RoutingTable(self, ksize, source_node)
|
|
self.storage = storage
|
|
self.source_node = source_node
|
|
|
|
def get_refresh_ids(self):
|
|
"""
|
|
Get ids to search for to keep old buckets up to date.
|
|
"""
|
|
ids = []
|
|
for bucket in self.router.lonely_buckets():
|
|
rid = random.randint(*bucket.range).to_bytes(20, byteorder='big')
|
|
ids.append(rid)
|
|
return ids
|
|
|
|
def rpc_add_provider(self, sender, nodeid, key):
|
|
pass
|
|
|
|
def rpc_get_providers(self, sender, nodeid, key):
|
|
pass
|
|
|
|
def rpc_stun(self, sender): # pylint: disable=no-self-use
|
|
return sender
|
|
|
|
def rpc_ping(self, sender, nodeid):
|
|
source = Node(nodeid, sender[0], sender[1])
|
|
self.welcome_if_new(source)
|
|
return self.source_node.id
|
|
|
|
def rpc_store(self, sender, nodeid, key, value):
|
|
source = Node(nodeid, sender[0], sender[1])
|
|
self.welcome_if_new(source)
|
|
log.debug("got a store request from %s, storing '%s'='%s'",
|
|
sender, key.hex(), value)
|
|
self.storage[key] = value
|
|
return True
|
|
|
|
def rpc_find_node(self, sender, nodeid, key):
|
|
log.info("finding neighbors of %i in local table",
|
|
int(nodeid.hex(), 16))
|
|
source = Node(nodeid, sender[0], sender[1])
|
|
self.welcome_if_new(source)
|
|
node = Node(key)
|
|
neighbors = self.router.find_neighbors(node, exclude=source)
|
|
return list(map(tuple, neighbors))
|
|
|
|
def rpc_find_value(self, sender, nodeid, key):
|
|
source = Node(nodeid, sender[0], sender[1])
|
|
self.welcome_if_new(source)
|
|
value = self.storage.get(key, None)
|
|
if value is None:
|
|
return self.rpc_find_node(sender, nodeid, key)
|
|
return {'value': value}
|
|
|
|
async def call_find_node(self, node_to_ask, node_to_find):
|
|
address = (node_to_ask.ip, node_to_ask.port)
|
|
result = await self.find_node(address, self.source_node.id,
|
|
node_to_find.id)
|
|
return self.handle_call_response(result, node_to_ask)
|
|
|
|
async def call_find_value(self, node_to_ask, node_to_find):
|
|
address = (node_to_ask.ip, node_to_ask.port)
|
|
result = await self.find_value(address, self.source_node.id,
|
|
node_to_find.id)
|
|
return self.handle_call_response(result, node_to_ask)
|
|
|
|
async def call_ping(self, node_to_ask):
|
|
address = (node_to_ask.ip, node_to_ask.port)
|
|
result = await self.ping(address, self.source_node.id)
|
|
return self.handle_call_response(result, node_to_ask)
|
|
|
|
async def call_store(self, node_to_ask, key, value):
|
|
address = (node_to_ask.ip, node_to_ask.port)
|
|
result = await self.store(address, self.source_node.id, key, value)
|
|
return self.handle_call_response(result, node_to_ask)
|
|
|
|
def welcome_if_new(self, node):
|
|
"""
|
|
Given a new node, send it all the keys/values it should be storing,
|
|
then add it to the routing table.
|
|
|
|
@param node: A new node that just joined (or that we just found out
|
|
about).
|
|
|
|
Process:
|
|
For each key in storage, get k closest nodes. If newnode is closer
|
|
than the furtherst in that list, and the node for this server
|
|
is closer than the closest in that list, then store the key/value
|
|
on the new node (per section 2.5 of the paper)
|
|
"""
|
|
if not self.router.is_new_node(node):
|
|
return
|
|
|
|
log.info("never seen %s before, adding to router", node)
|
|
for key, value in self.storage:
|
|
keynode = Node(digest(key))
|
|
neighbors = self.router.find_neighbors(keynode)
|
|
if neighbors:
|
|
last = neighbors[-1].distance_to(keynode)
|
|
new_node_close = node.distance_to(keynode) < last
|
|
first = neighbors[0].distance_to(keynode)
|
|
this_closest = self.source_node.distance_to(keynode) < first
|
|
if not neighbors or (new_node_close and this_closest):
|
|
asyncio.ensure_future(self.call_store(node, key, value))
|
|
self.router.add_contact(node)
|
|
|
|
def handle_call_response(self, result, node):
|
|
"""
|
|
If we get a response, add the node to the routing table. If
|
|
we get no response, make sure it's removed from the routing table.
|
|
"""
|
|
if not result[0]:
|
|
log.warning("no response from %s, removing from router", node)
|
|
self.router.remove_contact(node)
|
|
return result
|
|
|
|
log.info("got successful response from %s", node)
|
|
self.welcome_if_new(node)
|
|
return result
|