342 lines
14 KiB
Python
342 lines
14 KiB
Python
import asyncio
|
|
import random
|
|
import logging
|
|
import typing
|
|
import itertools
|
|
|
|
from prometheus_client import Gauge, Counter
|
|
|
|
from lbry.dht import constants
|
|
from lbry.dht.protocol.distance import Distance
|
|
if typing.TYPE_CHECKING:
|
|
from lbry.dht.peer import KademliaPeer, PeerManager
|
|
|
|
log = logging.getLogger(__name__)
|
|
|
|
|
|
class KBucket:
|
|
"""
|
|
Kademlia K-bucket implementation.
|
|
"""
|
|
peer_in_routing_table_metric = Gauge(
|
|
"peers_in_routing_table", "Number of peers on routing table", namespace="dht_node",
|
|
labelnames=("scope",)
|
|
)
|
|
peer_with_x_byte_colliding_metric = Counter(
|
|
"peer_x_byte_colliding", "Number of peers with at least X bytes colliding with this node id",
|
|
namespace="dht_node", labelnames=("amount",)
|
|
)
|
|
|
|
def __init__(self, peer_manager: 'PeerManager', range_min: int, range_max: int, node_id: bytes):
|
|
"""
|
|
@param range_min: The lower boundary for the range in the n-bit ID
|
|
space covered by this k-bucket
|
|
@param range_max: The upper boundary for the range in the ID space
|
|
covered by this k-bucket
|
|
"""
|
|
self._peer_manager = peer_manager
|
|
self.last_accessed = 0
|
|
self.range_min = range_min
|
|
self.range_max = range_max
|
|
self.peers: typing.List['KademliaPeer'] = []
|
|
self._node_id = node_id
|
|
self._distance_to_self = Distance(node_id)
|
|
|
|
def add_peer(self, peer: 'KademliaPeer') -> bool:
|
|
""" Add contact to _contact list in the right order. This will move the
|
|
contact to the end of the k-bucket if it is already present.
|
|
|
|
@raise kademlia.kbucket.BucketFull: Raised when the bucket is full and
|
|
the contact isn't in the bucket
|
|
already
|
|
|
|
@param peer: The contact to add
|
|
@type peer: dht.contact._Contact
|
|
"""
|
|
if peer in self.peers:
|
|
# Move the existing contact to the end of the list
|
|
# - using the new contact to allow add-on data
|
|
# (e.g. optimization-specific stuff) to pe updated as well
|
|
self.peers.remove(peer)
|
|
self.peers.append(peer)
|
|
return True
|
|
else:
|
|
for i, _ in enumerate(self.peers):
|
|
local_peer = self.peers[i]
|
|
if local_peer.node_id == peer.node_id:
|
|
self.peers.remove(local_peer)
|
|
self.peers.append(peer)
|
|
return True
|
|
if len(self.peers) < constants.K:
|
|
self.peers.append(peer)
|
|
self.peer_in_routing_table_metric.labels("global").inc()
|
|
if self._node_id[0] == peer.node_id[0]:
|
|
amount = 2 if self._node_id[1] == peer.node_id[1] else 1
|
|
self.peer_with_x_byte_colliding_metric.labels(amount=amount).inc()
|
|
return True
|
|
else:
|
|
return False
|
|
# raise BucketFull("No space in bucket to insert contact")
|
|
|
|
def get_peer(self, node_id: bytes) -> 'KademliaPeer':
|
|
for peer in self.peers:
|
|
if peer.node_id == node_id:
|
|
return peer
|
|
raise IndexError(node_id)
|
|
|
|
def get_peers(self, count=-1, exclude_contact=None, sort_distance_to=None) -> typing.List['KademliaPeer']:
|
|
""" Returns a list containing up to the first count number of contacts
|
|
|
|
@param count: The amount of contacts to return (if 0 or less, return
|
|
all contacts)
|
|
@type count: int
|
|
@param exclude_contact: A node node_id to exclude; if this contact is in
|
|
the list of returned values, it will be
|
|
discarded before returning. If a C{str} is
|
|
passed as this argument, it must be the
|
|
contact's ID.
|
|
@type exclude_contact: str
|
|
|
|
@param sort_distance_to: Sort distance to the node_id, defaulting to the parent node node_id. If False don't
|
|
sort the contacts
|
|
|
|
@raise IndexError: If the number of requested contacts is too large
|
|
|
|
@return: Return up to the first count number of contacts in a list
|
|
If no contacts are present an empty is returned
|
|
@rtype: list
|
|
"""
|
|
peers = [peer for peer in self.peers if peer.node_id != exclude_contact]
|
|
|
|
# Return all contacts in bucket
|
|
if count <= 0:
|
|
count = len(peers)
|
|
|
|
# Get current contact number
|
|
current_len = len(peers)
|
|
|
|
# If count greater than k - return only k contacts
|
|
if count > constants.K:
|
|
count = constants.K
|
|
|
|
if not current_len:
|
|
return peers
|
|
|
|
if sort_distance_to is False:
|
|
pass
|
|
else:
|
|
sort_distance_to = sort_distance_to or self._node_id
|
|
peers.sort(key=lambda c: Distance(sort_distance_to)(c.node_id))
|
|
|
|
return peers[:min(current_len, count)]
|
|
|
|
def get_bad_or_unknown_peers(self) -> typing.List['KademliaPeer']:
|
|
peer = self.get_peers(sort_distance_to=False)
|
|
return [
|
|
peer for peer in peer
|
|
if self._peer_manager.contact_triple_is_good(peer.node_id, peer.address, peer.udp_port) is not True
|
|
]
|
|
|
|
def remove_peer(self, peer: 'KademliaPeer') -> None:
|
|
self.peers.remove(peer)
|
|
self.peer_in_routing_table_metric.labels("global").dec()
|
|
|
|
def key_in_range(self, key: bytes) -> bool:
|
|
""" Tests whether the specified key (i.e. node ID) is in the range
|
|
of the n-bit ID space covered by this k-bucket (in otherwords, it
|
|
returns whether or not the specified key should be placed in this
|
|
k-bucket)
|
|
|
|
@param key: The key to test
|
|
@type key: str or int
|
|
|
|
@return: C{True} if the key is in this k-bucket's range, or C{False}
|
|
if not.
|
|
@rtype: bool
|
|
"""
|
|
return self.range_min <= self._distance_to_self(key) < self.range_max
|
|
|
|
def __len__(self) -> int:
|
|
return len(self.peers)
|
|
|
|
def __contains__(self, item) -> bool:
|
|
return item in self.peers
|
|
|
|
|
|
class TreeRoutingTable:
|
|
""" This class implements a routing table used by a Node class.
|
|
|
|
The Kademlia routing table is a binary tree whose leaves are k-buckets,
|
|
where each k-bucket contains nodes with some common prefix of their IDs.
|
|
This prefix is the k-bucket's position in the binary tree; it therefore
|
|
covers some range of ID values, and together all of the k-buckets cover
|
|
the entire n-bit ID (or key) space (with no overlap).
|
|
|
|
@note: In this implementation, nodes in the tree (the k-buckets) are
|
|
added dynamically, as needed; this technique is described in the 13-page
|
|
version of the Kademlia paper, in section 2.4. It does, however, use the
|
|
ping RPC-based k-bucket eviction algorithm described in section 2.2 of
|
|
that paper.
|
|
"""
|
|
bucket_in_routing_table_metric = Gauge(
|
|
"buckets_in_routing_table", "Number of buckets on routing table", namespace="dht_node",
|
|
labelnames=("scope",)
|
|
)
|
|
|
|
def __init__(self, loop: asyncio.AbstractEventLoop, peer_manager: 'PeerManager', parent_node_id: bytes,
|
|
split_buckets_under_index: int = constants.SPLIT_BUCKETS_UNDER_INDEX):
|
|
self._loop = loop
|
|
self._peer_manager = peer_manager
|
|
self._parent_node_id = parent_node_id
|
|
self._split_buckets_under_index = split_buckets_under_index
|
|
self.buckets: typing.List[KBucket] = [
|
|
KBucket(
|
|
self._peer_manager, range_min=0, range_max=2 ** constants.HASH_BITS, node_id=self._parent_node_id
|
|
)
|
|
]
|
|
|
|
def get_peers(self) -> typing.List['KademliaPeer']:
|
|
return list(itertools.chain.from_iterable(map(lambda bucket: bucket.peers, self.buckets)))
|
|
|
|
def should_split(self, bucket_index: int, to_add: bytes) -> bool:
|
|
# https://stackoverflow.com/questions/32129978/highly-unbalanced-kademlia-routing-table/32187456#32187456
|
|
if bucket_index < self._split_buckets_under_index:
|
|
return True
|
|
contacts = self.get_peers()
|
|
distance = Distance(self._parent_node_id)
|
|
contacts.sort(key=lambda c: distance(c.node_id))
|
|
kth_contact = contacts[-1] if len(contacts) < constants.K else contacts[constants.K - 1]
|
|
return distance(to_add) < distance(kth_contact.node_id)
|
|
|
|
def find_close_peers(self, key: bytes, count: typing.Optional[int] = None,
|
|
sender_node_id: typing.Optional[bytes] = None) -> typing.List['KademliaPeer']:
|
|
exclude = [self._parent_node_id]
|
|
if sender_node_id:
|
|
exclude.append(sender_node_id)
|
|
count = count or constants.K
|
|
distance = Distance(key)
|
|
contacts = self.get_peers()
|
|
contacts = [c for c in contacts if c.node_id not in exclude]
|
|
if contacts:
|
|
contacts.sort(key=lambda c: distance(c.node_id))
|
|
return contacts[:min(count, len(contacts))]
|
|
return []
|
|
|
|
def get_peer(self, contact_id: bytes) -> 'KademliaPeer':
|
|
"""
|
|
@raise IndexError: No contact with the specified contact ID is known
|
|
by this node
|
|
"""
|
|
return self.buckets[self.kbucket_index(contact_id)].get_peer(contact_id)
|
|
|
|
def get_refresh_list(self, start_index: int = 0, force: bool = False) -> typing.List[bytes]:
|
|
bucket_index = start_index
|
|
refresh_ids = []
|
|
now = int(self._loop.time())
|
|
for bucket in self.buckets[start_index:]:
|
|
if force or now - bucket.last_accessed >= constants.REFRESH_INTERVAL:
|
|
to_search = self.midpoint_id_in_bucket_range(bucket_index)
|
|
refresh_ids.append(to_search)
|
|
bucket_index += 1
|
|
return refresh_ids
|
|
|
|
def remove_peer(self, peer: 'KademliaPeer') -> None:
|
|
if not peer.node_id:
|
|
return
|
|
bucket_index = self.kbucket_index(peer.node_id)
|
|
try:
|
|
self.buckets[bucket_index].remove_peer(peer)
|
|
except ValueError:
|
|
return
|
|
|
|
def touch_kbucket(self, key: bytes) -> None:
|
|
self.touch_kbucket_by_index(self.kbucket_index(key))
|
|
|
|
def touch_kbucket_by_index(self, bucket_index: int):
|
|
self.buckets[bucket_index].last_accessed = int(self._loop.time())
|
|
|
|
def kbucket_index(self, key: bytes) -> int:
|
|
i = 0
|
|
for bucket in self.buckets:
|
|
if bucket.key_in_range(key):
|
|
return i
|
|
else:
|
|
i += 1
|
|
return i
|
|
|
|
def random_id_in_bucket_range(self, bucket_index: int) -> bytes:
|
|
random_id = int(random.randrange(self.buckets[bucket_index].range_min, self.buckets[bucket_index].range_max))
|
|
return Distance(
|
|
self._parent_node_id
|
|
)(random_id.to_bytes(constants.HASH_LENGTH, 'big')).to_bytes(constants.HASH_LENGTH, 'big')
|
|
|
|
def midpoint_id_in_bucket_range(self, bucket_index: int) -> bytes:
|
|
half = int((self.buckets[bucket_index].range_max - self.buckets[bucket_index].range_min) // 2)
|
|
return Distance(self._parent_node_id)(
|
|
int(self.buckets[bucket_index].range_min + half).to_bytes(constants.HASH_LENGTH, 'big')
|
|
).to_bytes(constants.HASH_LENGTH, 'big')
|
|
|
|
def split_bucket(self, old_bucket_index: int) -> None:
|
|
""" Splits the specified k-bucket into two new buckets which together
|
|
cover the same range in the key/ID space
|
|
|
|
@param old_bucket_index: The index of k-bucket to split (in this table's
|
|
list of k-buckets)
|
|
@type old_bucket_index: int
|
|
"""
|
|
# Resize the range of the current (old) k-bucket
|
|
old_bucket = self.buckets[old_bucket_index]
|
|
split_point = old_bucket.range_max - (old_bucket.range_max - old_bucket.range_min) // 2
|
|
# Create a new k-bucket to cover the range split off from the old bucket
|
|
new_bucket = KBucket(self._peer_manager, split_point, old_bucket.range_max, self._parent_node_id)
|
|
old_bucket.range_max = split_point
|
|
# Now, add the new bucket into the routing table tree
|
|
self.buckets.insert(old_bucket_index + 1, new_bucket)
|
|
# Finally, copy all nodes that belong to the new k-bucket into it...
|
|
for contact in old_bucket.peers:
|
|
if new_bucket.key_in_range(contact.node_id):
|
|
new_bucket.add_peer(contact)
|
|
# ...and remove them from the old bucket
|
|
for contact in new_bucket.peers:
|
|
old_bucket.remove_peer(contact)
|
|
self.bucket_in_routing_table_metric.labels("global").set(len(self.buckets))
|
|
|
|
def join_buckets(self):
|
|
if len(self.buckets) == 1:
|
|
return
|
|
to_pop = [i for i, bucket in enumerate(self.buckets) if len(bucket) == 0]
|
|
if not to_pop:
|
|
return
|
|
log.info("join buckets %i", len(to_pop))
|
|
bucket_index_to_pop = to_pop[0]
|
|
assert len(self.buckets[bucket_index_to_pop]) == 0
|
|
can_go_lower = bucket_index_to_pop - 1 >= 0
|
|
can_go_higher = bucket_index_to_pop + 1 < len(self.buckets)
|
|
assert can_go_higher or can_go_lower
|
|
bucket = self.buckets[bucket_index_to_pop]
|
|
if can_go_lower and can_go_higher:
|
|
midpoint = ((bucket.range_max - bucket.range_min) // 2) + bucket.range_min
|
|
self.buckets[bucket_index_to_pop - 1].range_max = midpoint - 1
|
|
self.buckets[bucket_index_to_pop + 1].range_min = midpoint
|
|
elif can_go_lower:
|
|
self.buckets[bucket_index_to_pop - 1].range_max = bucket.range_max
|
|
elif can_go_higher:
|
|
self.buckets[bucket_index_to_pop + 1].range_min = bucket.range_min
|
|
self.buckets.remove(bucket)
|
|
self.bucket_in_routing_table_metric.labels("global").set(len(self.buckets))
|
|
return self.join_buckets()
|
|
|
|
def contact_in_routing_table(self, address_tuple: typing.Tuple[str, int]) -> bool:
|
|
for bucket in self.buckets:
|
|
for contact in bucket.get_peers(sort_distance_to=False):
|
|
if address_tuple[0] == contact.address and address_tuple[1] == contact.udp_port:
|
|
return True
|
|
return False
|
|
|
|
def buckets_with_contacts(self) -> int:
|
|
count = 0
|
|
for bucket in self.buckets:
|
|
if len(bucket) > 0:
|
|
count += 1
|
|
return count
|