From 7eb9f344f41d3b0045a7cec04d2cb368edcf12a2 Mon Sep 17 00:00:00 2001
From: Victor Shyba <victor1984@riseup.net>
Date: Fri, 28 Sep 2018 13:47:37 -0300
Subject: [PATCH 1/2] test recover from invalid tokens

---
 tests/functional/dht/test_store.py | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/tests/functional/dht/test_store.py b/tests/functional/dht/test_store.py
index f5dc8a648..2fabd05ab 100644
--- a/tests/functional/dht/test_store.py
+++ b/tests/functional/dht/test_store.py
@@ -13,6 +13,31 @@ log = logging.getLogger()
 class TestStoreExpiration(TestKademliaBase):
     network_size = 40
 
+    @defer.inlineCallbacks
+    def test_nullify_token(self):
+        blob_hash = generate_id(1)
+        announcing_node = self.nodes[20]
+        # announce the blob
+        announce_d = announcing_node.announceHaveBlob(blob_hash)
+        self.pump_clock(5+1)
+        storing_node_ids = yield announce_d
+        self.assertEqual(len(storing_node_ids), 8)
+
+        for node in set(self.nodes).union(set(self._seeds)):
+            # now, everyone has the wrong token
+            node.change_token()
+            node.change_token()
+
+        announce_d = announcing_node.announceHaveBlob(blob_hash)
+        self.pump_clock(5+1)
+        storing_node_ids = yield announce_d
+        self.assertEqual(len(storing_node_ids), 0)  # cant store, wrong tokens, but they get nullified
+
+        announce_d = announcing_node.announceHaveBlob(blob_hash)
+        self.pump_clock(5+1)
+        storing_node_ids = yield announce_d
+        self.assertEqual(len(storing_node_ids), 8)  # next attempt succeeds as it refreshes tokens
+
     @defer.inlineCallbacks
     def test_store_and_expire(self):
         blob_hash = generate_id(1)

From 9178ca701c87772100634567a03dd822af77ee0d Mon Sep 17 00:00:00 2001
From: Victor Shyba <victor1984@riseup.net>
Date: Fri, 28 Sep 2018 14:19:51 -0300
Subject: [PATCH 2/2] nullify and refresh tokens

---
 lbrynet/dht/contact.py  |  2 +-
 lbrynet/dht/node.py     | 15 +++++++--------
 lbrynet/dht/protocol.py |  2 ++
 3 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/lbrynet/dht/contact.py b/lbrynet/dht/contact.py
index 101492ef3..bc25fc5d5 100644
--- a/lbrynet/dht/contact.py
+++ b/lbrynet/dht/contact.py
@@ -40,7 +40,7 @@ class _Contact:
         self._token = (None, 0)  # token, timestamp
 
     def update_token(self, token):
-        self._token = token, self.getTime()
+        self._token = token, self.getTime() if token else 0
 
     @property
     def token(self):
diff --git a/lbrynet/dht/node.py b/lbrynet/dht/node.py
index ce9d2da81..960136b41 100644
--- a/lbrynet/dht/node.py
+++ b/lbrynet/dht/node.py
@@ -299,25 +299,24 @@ class Node(MockKademliaHelper):
     @defer.inlineCallbacks
     def storeToContact(self, blob_hash, contact):
         try:
-            token = contact.token
-            if not token:
-                find_value_response = yield contact.findValue(blob_hash)
-                token = find_value_response[b'token']
-                contact.update_token(token)
-            res = yield contact.store(blob_hash, token, self.peerPort, self.node_id, 0)
+            if not contact.token:
+                yield contact.findValue(blob_hash)
+            res = yield contact.store(blob_hash, contact.token, self.peerPort, self.node_id, 0)
             if res != b"OK":
                 raise ValueError(res)
-            defer.returnValue(True)
             log.debug("Stored %s to %s (%s)", binascii.hexlify(blob_hash), contact.log_id(), contact.address)
+            return True
         except protocol.TimeoutError:
             log.debug("Timeout while storing blob_hash %s at %s",
                       binascii.hexlify(blob_hash), contact.log_id())
         except ValueError as err:
             log.error("Unexpected response: %s" % err)
         except Exception as err:
+            if 'Invalid token' in str(err):
+                contact.update_token(None)
             log.error("Unexpected error while storing blob_hash %s at %s: %s",
                       binascii.hexlify(blob_hash), contact, err)
-        defer.returnValue(False)
+        return False
 
     @defer.inlineCallbacks
     def announceHaveBlob(self, blob_hash):
diff --git a/lbrynet/dht/protocol.py b/lbrynet/dht/protocol.py
index e3130468c..b26364410 100644
--- a/lbrynet/dht/protocol.py
+++ b/lbrynet/dht/protocol.py
@@ -184,6 +184,8 @@ class KademliaProtocol(protocol.DatagramProtocol):
         def _update_contact(result):  # refresh the contact in the routing table
             contact.update_last_replied()
             if method == b'findValue':
+                if b'token' in result:
+                    contact.update_token(result[b'token'])
                 if b'protocolVersion' not in result:
                     contact.update_protocol_version(0)
                 else: