Rendezvous Certificates

src/tribler/core/components/popularity/community/popularity_community.py

@@ -5,11 +5,18 @@
 from typing import List, TYPE_CHECKING
 
 from ipv8.lazy_community import lazy_wrapper
+from ipv8.messaging.interfaces.udp.endpoint import UDPv4Address, UDPv4LANAddress
+from ipv8.messaging.serialization import PackError
 from pony.orm import db_session
 
 from tribler.core.components.metadata_store.remote_query_community.remote_query_community import RemoteQueryCommunity
 from tribler.core.components.popularity.community.payload import PopularTorrentsRequest, TorrentsHealthPayload
 from tribler.core.components.popularity.community.version_community_mixin import VersionCommunityMixin
+from tribler.core.components.popularity.rendezvous.db.database import RendezvousDatabase
+from tribler.core.components.popularity.rendezvous.rendezvous import RendezvousRequestPayload, \
+    RendezvousResponsePayload, RawRendezvousResponsePayload, \
+    RendezvousChallenge, RendezvousSignature
+from tribler.core.components.popularity.rendezvous.rendezvous_cache import RendezvousCache, EMPTY_PEER_CHALLENGE
 from tribler.core.components.torrent_checker.torrent_checker.dataclasses import HealthInfo
 from tribler.core.utilities.pony_utils import run_threaded
 from tribler.core.utilities.unicode import hexlify
@@ -35,22 +42,97 @@ class PopularityCommunity(RemoteQueryCommunity, VersionCommunityMixin):
     GOSSIP_POPULAR_TORRENT_COUNT = 10
     GOSSIP_RANDOM_TORRENT_COUNT = 10
 
+    PING_INTERVAL_RENDEZVOUS = 60  # seconds
+
     community_id = unhexlify('9aca62f878969c437da9844cba29a134917e1648')
 
-    def __init__(self, *args, torrent_checker=None, **kwargs):
+    def __init__(self, *args, torrent_checker=None, rendezvous_db=None, **kwargs):
         # Creating a separate instance of Network for this community to find more peers
         super().__init__(*args, **kwargs)
+
+        self.rdb: RendezvousDatabase = rendezvous_db
         self.torrent_checker: TorrentChecker = torrent_checker
 
         self.add_message_handler(TorrentsHealthPayload, self.on_torrents_health)
         self.add_message_handler(PopularTorrentsRequest, self.on_popular_torrents_request)
 
+        self.add_message_handler(RendezvousRequestPayload, self.on_rendezvous_request)
+        self.add_message_handler(RendezvousResponsePayload, self.on_rendezvous_response)
+
         self.logger.info('Popularity Community initialized (peer mid %s)', hexlify(self.my_peer.mid))
         self.register_task("gossip_random_torrents", self.gossip_random_torrents_health,
-                           interval=PopularityCommunity.GOSSIP_INTERVAL_FOR_RANDOM_TORRENTS)
+                           interval=self.GOSSIP_INTERVAL_FOR_RANDOM_TORRENTS)
+        self.register_task("ping_rendezvous", self.ping_rendezvous,
+                           interval=self.PING_INTERVAL_RENDEZVOUS)
 
         # Init version community message handlers
         self.init_version_community()
+        self.rendezvous_cache = RendezvousCache()
+
+    def send_introduction_request(self, peer):
+        rendezvous_request = self._create_rendezvous_request()
+        extra_payload = self.serializer.pack_serializable(rendezvous_request)
+        self.logger.debug("Piggy-backing Rendezvous to %s:%d", peer.address[0], peer.address[1])
+        packet = self.create_introduction_request(peer.address, extra_bytes=extra_payload,
+                                                  new_style=peer.new_style_intro)
+        self.endpoint.send(peer.address, packet)
+        self.rendezvous_cache.add_peer(peer, rendezvous_request.challenge.nonce)
+
+    # We override this method to add the rendezvous certificate to the introduction request
+    def on_introduction_request(self, peer, dist, payload):
+        if 0 <= self.max_peers < len(self.get_peers()):
+            self.logger.debug("Dropping introduction request from (%s, %d): too many peers!",
+                              peer.address[0], peer.address[1])
+            return
+
+        extra_payload = b''
+        if payload.extra_bytes:
+            self.logger.debug("Received introduction request with extra bytes")
+            try:
+                rendezvous_request, _ = self.serializer.unpack_serializable(RendezvousRequestPayload,
+                                                                            payload.extra_bytes)
+                rendezvous_response = self._create_rendezvous_response(rendezvous_request.challenge)
+                # As we are sending the rendezvous response, we know this peer is interested in rendezvous.
+                self.rendezvous_cache.add_peer(peer)
+                extra_payload = self.serializer.pack_serializable(rendezvous_response)
+            except PackError as e:
+                self.logger.warning("Failed to unpack RendezvousRequestPayload: %s", e)
+
+        if isinstance(payload.source_lan_address, UDPv4Address):
+            peer.address = UDPv4LANAddress(*payload.source_lan_address)
+        self.network.add_verified_peer(peer)
+        self.network.discover_services(peer, [self.community_id, ])
+
+        packet = self.create_introduction_response(payload.destination_address, peer.address, payload.identifier,
+                                                   extra_bytes=extra_payload, new_style=peer.new_style_intro)
+
+        self.endpoint.send(peer.address, packet)
+        self.introduction_request_callback(peer, dist, payload)
+
+    @lazy_wrapper(RendezvousRequestPayload)
+    def on_rendezvous_request(self, peer, payload: RendezvousRequestPayload):
+        self.logger.debug("Received rendezvous request from %s:%d", peer.address[0], peer.address[1])
+        # As we are sending the rendezvous response, we know this peer is interested in rendezvous.
+        self.rendezvous_cache.add_peer(peer)
+        rendezvous_response = self._create_rendezvous_response(payload.challenge)
+        self.ez_send(peer, rendezvous_response)
+
+    @lazy_wrapper(RawRendezvousResponsePayload)
+    def on_rendezvous_response(self, peer, payload: RawRendezvousResponsePayload):
+        self.logger.debug("Received rendezvous response from %s:%d", peer.address[0], peer.address[1])
+        self._handle_rendezvous_response(peer, payload)
+
+    def introduction_response_callback(self, peer, dist, payload):
+        super().introduction_response_callback(peer, dist, payload)
+        if payload.extra_bytes:
+            self.logger.debug("Received introduction response with extra bytes")
+            try:
+                raw_rendezvous_response, _ = self.serializer.unpack_serializable(RawRendezvousResponsePayload,
+                                                                                 payload.extra_bytes)
+                self._handle_rendezvous_response(peer, raw_rendezvous_response)
+
+            except PackError as e:
+                self.logger.warning("Failed to unpack RendezvousResponsePayload: %s", e)
 
     def introduction_request_callback(self, peer, dist, payload):
         super().introduction_request_callback(peer, dist, payload)
@@ -76,6 +158,15 @@ def gossip_random_torrents_health(self):
 
         self.ez_send(random_peer, TorrentsHealthPayload.create(random_torrents, {}))
 
+    def ping_rendezvous(self):
+        # Remove peers that haven't replied in a while.
+        self.rendezvous_cache.clear_inactive_peers()
+
+        for peer in self.rendezvous_cache.get_rendezvous_peers():
+            payload = self._create_rendezvous_request()
+            self.rendezvous_cache.set_rendezvous_challenge(peer, payload.challenge.nonce)
+            self.ez_send(peer, payload)
+
     @lazy_wrapper(TorrentsHealthPayload)
     async def on_torrents_health(self, peer, payload):
         self.logger.debug(f"Received torrent health information for "
@@ -140,3 +231,36 @@ def get_random_torrents(self) -> List[HealthInfo]:
 
         random_torrents = random.sample(checked_and_alive, num_torrents_to_send)
         return random_torrents
+
+    def _create_rendezvous_request(self) -> RendezvousRequestPayload:
+        challenge = RendezvousChallenge.create()
+        payload = RendezvousRequestPayload(challenge)
+        return payload
+
+    def _create_rendezvous_response(self, challenge: RendezvousChallenge) -> RendezvousResponsePayload:
+        signature = challenge.sign(self.my_peer.key)
+        payload = RendezvousResponsePayload(challenge, RendezvousSignature(signature))
+        return payload
+
+    def _handle_rendezvous_response(self, peer, raw_payload: RawRendezvousResponsePayload):
+        signature, _ = self.serializer.unpack_serializable(RendezvousSignature, raw_payload.signature)
+        challenge, _ = self.serializer.unpack_serializable(RendezvousChallenge, raw_payload.challenge)
+
+        expected_nonce = self.rendezvous_cache.get_rendezvous_challenge(peer) or EMPTY_PEER_CHALLENGE
+        if expected_nonce == EMPTY_PEER_CHALLENGE or expected_nonce != challenge.nonce:
+            self.logger.warning(f"Received invalid rendezvous response from {peer.mid}")
+            return
+
+        if not self.crypto.is_valid_signature(peer.key, raw_payload.challenge, signature.signature):
+            self.logger.warning(f"Received invalid signature from {peer.mid}")
+            return
+
+        # This nonce has been burned.
+        self.rendezvous_cache.clear_peer_challenge(peer)
+
+        self.logger.debug(f"Received valid rendezvous response from {peer.mid}")
+        with db_session(immediate=True):
+            certificate = self.rdb.Certificate.get(public_key=peer.mid)
+            if not certificate:
+                certificate = self.rdb.Certificate(public_key=peer.mid, counter=0)
+            certificate.counter += 1

src/tribler/core/components/popularity/community/tests/test_popularity_community.py

@@ -11,6 +11,8 @@
 from tribler.core.components.metadata_store.db.store import MetadataStore
 from tribler.core.components.metadata_store.remote_query_community.settings import RemoteQueryCommunitySettings
 from tribler.core.components.popularity.community.popularity_community import PopularityCommunity
+from tribler.core.components.popularity.rendezvous.db.database import RendezvousDatabase
+from tribler.core.components.popularity.rendezvous.rendezvous import RendezvousChallenge
 from tribler.core.components.torrent_checker.torrent_checker.torrentchecker_session import HealthInfo
 from tribler.core.tests.tools.base_test import MockObject
 from tribler.core.utilities.path_util import Path
@@ -210,3 +212,102 @@ async def test_skip_torrent_query_back_for_known_torrent(self):
         await self.init_first_node_and_gossip(
             HealthInfo(infohash, seeders=200, leechers=0))
         self.nodes[1].overlay.send_remote_select.assert_not_called()
+
+
+class TestRendezvousLogic(TestBase):
+    NUM_NODES = 3
+
+    def setUp(self):
+        super().setUp()
+        self.count = 0
+        self.initialize(PopularityCommunity, self.NUM_NODES)
+
+    def create_node(self, *args, **kwargs):
+        rdb = RendezvousDatabase(Path(self.temporary_directory()) / f"{self.count + 1}")
+        torrent_checker = MockObject()
+        torrent_checker.torrents_checked = {}
+        mds = MetadataStore(Path(self.temporary_directory()) / f"{self.count}",
+                            Path(self.temporary_directory()),
+                            default_eccrypto.generate_key("curve25519"))
+        rqc_settings = RemoteQueryCommunitySettings()
+
+        self.count += 1
+        return MockIPv8("curve25519", PopularityCommunity, metadata_store=mds,
+                        rendezvous_db=rdb,
+                        torrent_checker=torrent_checker,
+                        rqc_settings=rqc_settings
+                        )
+
+    async def test_introduction_rendezvous_payload(self):
+        await self.introduce_nodes()
+        await self.deliver_messages()
+
+        self.nodes[0].overlay.send_introduction_request(self.nodes[1].my_peer)
+        await self.deliver_messages()
+
+        self.nodes[0].overlay.send_introduction_request(self.nodes[2].my_peer)
+        await self.deliver_messages()
+
+        with db_session:
+            assert self.nodes[0].overlay.rdb.Certificate.get(public_key=self.nodes[1].my_peer.mid).counter == 1
+            assert self.nodes[0].overlay.rdb.Certificate.get(public_key=self.nodes[2].my_peer.mid).counter == 1
+
+        # Check if the rendezvous cache is updated
+        rendezvous_peers = list(self.nodes[1].overlay.rendezvous_cache.get_rendezvous_peers())
+        assert rendezvous_peers[0] == self.nodes[0].my_peer
+        rendezvous_peers = list(self.nodes[2].overlay.rendezvous_cache.get_rendezvous_peers())
+        assert rendezvous_peers[0] == self.nodes[0].my_peer
+
+    async def test_rendezvous_payloads(self):
+        await self.introduce_nodes()
+        await self.deliver_messages()
+
+        self.nodes[0].overlay.send_introduction_request(self.nodes[1].my_peer)
+        self.nodes[0].overlay.send_introduction_request(self.nodes[2].my_peer)
+        await self.deliver_messages()
+
+        number_of_rendezvous = 4
+        for _ in range(number_of_rendezvous):
+            for j in range(self.count):
+                self.nodes[j].overlay.ping_rendezvous()
+                await self.deliver_messages()
+
+        with db_session:
+            # Peer 0 should have a counter of 1 more
+            assert self.nodes[0].overlay.rdb.Certificate.get(
+                public_key=self.nodes[1].my_peer.mid).counter == number_of_rendezvous + 1
+            assert self.nodes[1].overlay.rdb.Certificate.get(
+                public_key=self.nodes[0].my_peer.mid).counter == number_of_rendezvous
+            assert self.nodes[2].overlay.rdb.Certificate.get(
+                public_key=self.nodes[0].my_peer.mid).counter == number_of_rendezvous
+
+    async def test_invalid_nonce(self):
+        await self.introduce_nodes()
+        await self.deliver_messages()
+
+        self.nodes[0].overlay.rendezvous_cache.add_peer(self.nodes[1].my_peer, b'1' * 16)
+
+        payload = self.nodes[1].overlay._create_rendezvous_response(RendezvousChallenge(b'2' * 16))
+        self.nodes[1].overlay.ez_send(self.nodes[0].my_peer, payload)
+        await self.deliver_messages()
+
+        with db_session:
+            assert self.nodes[0].overlay.rdb.Certificate.get(public_key=self.nodes[1].my_peer.mid) is None
+
+    async def test_invalid_signature(self):
+        await self.introduce_nodes()
+        await self.deliver_messages()
+
+        challenge_1 = RendezvousChallenge(b'1' * 16)
+        challenge_2 = RendezvousChallenge(b'2' * 16)
+
+        self.nodes[0].overlay.rendezvous_cache.add_peer(self.nodes[1].my_peer, challenge_1.nonce)
+
+        payload = self.nodes[1].overlay._create_rendezvous_response(challenge_2)
+        payload.challenge = challenge_1
+
+        self.nodes[1].overlay.ez_send(self.nodes[0].my_peer, payload)
+        await self.deliver_messages()
+
+        with db_session:
+            assert self.nodes[0].overlay.rdb.Certificate.get(public_key=self.nodes[1].my_peer.mid) is None

src/tribler/core/components/popularity/popularity_component.py

@@ -5,13 +5,17 @@
 from tribler.core.components.ipv8.ipv8_component import INFINITE, Ipv8Component
 from tribler.core.components.metadata_store.metadata_store_component import MetadataStoreComponent
 from tribler.core.components.popularity.community.popularity_community import PopularityCommunity
+from tribler.core.components.popularity.rendezvous.db.database import RendezvousDatabase
 from tribler.core.components.reporter.reporter_component import ReporterComponent
 from tribler.core.components.torrent_checker.torrent_checker_component import TorrentCheckerComponent
+from tribler.core.utilities.simpledefs import STATEDIR_DB_DIR
 
 
 class PopularityComponent(Component):
-    community: PopularityCommunity = None
+    RENDEZVOUS_DB_NAME = 'rendezvous.db'
 
+    community: PopularityCommunity = None
+    rendezvous_db: RendezvousDatabase = None
     _ipv8_component: Ipv8Component = None
 
     async def run(self):
@@ -22,13 +26,17 @@ async def run(self):
         metadata_store_component = await self.require_component(MetadataStoreComponent)
         torrent_checker_component = await self.require_component(TorrentCheckerComponent)
 
+        self.rendezvous_db = RendezvousDatabase(
+            db_path=self.session.config.state_dir / STATEDIR_DB_DIR / self.RENDEZVOUS_DB_NAME)
+
         config = self.session.config
         community = PopularityCommunity(self._ipv8_component.peer,
                                         self._ipv8_component.ipv8.endpoint,
                                         Network(),
                                         settings=config.popularity_community,
                                         rqc_settings=config.remote_query_community,
                                         metadata_store=metadata_store_component.mds,
+                                        rendezvous_db=self.rendezvous_db,
                                         torrent_checker=torrent_checker_component.torrent_checker)
         self.community = community
 
@@ -39,3 +47,5 @@ async def shutdown(self):
         await super().shutdown()
         if self._ipv8_component and self.community:
             await self._ipv8_component.unload_community(self.community)
+        if self.rendezvous_db:
+            self.rendezvous_db.shutdown()

src/tribler/core/components/popularity/rendezvous/db/database.py

@@ -0,0 +1,36 @@
+from pathlib import Path
+from typing import Union
+
+from pony.orm import Database, db_session
+
+from tribler.core.components.metadata_store.db.orm_bindings import misc
+from tribler.core.components.popularity.rendezvous.db.orm_bindings import certificate
+from tribler.core.utilities.utilities import MEMORY_DB
+
+
+class RendezvousDatabase:
+    DB_VERSION = 0
+
+    def __init__(self, db_path: Union[Path, type(MEMORY_DB)]):
+
+        self.database = Database()
+
+        self.MiscData = misc.define_binding(self.database)
+        self.Certificate = certificate.define_binding(self.database)
+
+        if db_path is MEMORY_DB:
+            create_db = True
+            db_path_string = ":memory:"
+        else:
+            create_db = not db_path.is_file()
+            db_path_string = str(db_path)
+
+        self.database.bind(provider='sqlite', filename=db_path_string, create_db=create_db, timeout=120.0)
+        self.database.generate_mapping(create_tables=create_db)
+
+        if create_db:
+            with db_session:
+                self.MiscData(name="db_version", value=str(self.DB_VERSION))
+
+    def shutdown(self) -> None:
+        self.database.disconnect()

src/tribler/core/components/popularity/rendezvous/db/orm_bindings/certificate.py

@@ -0,0 +1,9 @@
+from pony.orm import Required, db_session
+
+
+def define_binding(db):
+    class RendezvousCertificate(db.Entity):
+        public_key = Required(bytes, index=True)
+        counter = Required(int)
+
+    return RendezvousCertificate

src/tribler/core/components/popularity/rendezvous/db/orm_bindings/misc.py

@@ -0,0 +1,9 @@
+from pony.orm import Optional, PrimaryKey
+
+
+def define_binding(db):
+    class MiscData(db.Entity):
+        name = PrimaryKey(str)
+        value = Optional(str)
+
+    return MiscData