Merge pull request ethereum#618 from carver/connect-to-syncing-peers

Connect to unsynced peers, and trinity peers

Author: carver

p2p/peer_pool.py

@@ -245,12 +245,16 @@ def unsubscribe(self, subscriber: PeerSubscriber) -> None:
     async def start_peer(self, peer: BasePeer) -> None:
         self.run_child_service(peer)
         await self.wait(peer.events.started.wait(), timeout=1)
+        if peer.is_operational:
+            self._add_peer(peer, ())
+        else:
+            self.logger.debug("%s was cancelled immediately, not adding to pool", peer)
+
         try:
-            with peer.collect_sub_proto_messages() as buffer:
-                await self.wait(
-                    peer.boot_manager.events.finished.wait(),
-                    timeout=self._peer_boot_timeout
-                )
+            await self.wait(
+                peer.boot_manager.events.finished.wait(),
+                timeout=self._peer_boot_timeout
+            )
         except TimeoutError as err:
             self.logger.debug('Timout waiting for peer to boot: %s', err)
             await peer.disconnect(DisconnectReason.timeout)
@@ -259,10 +263,8 @@ async def start_peer(self, peer: BasePeer) -> None:
             await self.connection_tracker.record_failure(peer.remote, err)
             raise
         else:
-            if peer.is_operational:
-                self._add_peer(peer, buffer.get_messages())
-            else:
-                self.logger.debug('%s disconnected during boot-up, not adding to pool', peer)
+            if not peer.is_operational:
+                self.logger.debug('%s disconnected during boot-up, dropped from pool', peer)
 
     def _add_peer(self,
                   peer: BasePeer,

trinity/protocol/common/boot.py

@@ -2,6 +2,7 @@
 
 from eth_utils import ValidationError
 
+from eth.rlp.headers import BlockHeader
 from eth.vm.forks import HomesteadVM
 
 from p2p.exceptions import PeerConnectionLost
@@ -42,7 +43,8 @@ async def ensure_same_side_on_dao_fork(self) -> None:
                 # VM comes after the fork, so stop checking
                 break
 
-            start_block = vm_class.get_dao_fork_block_number() - 1
+            dao_fork_num = vm_class.get_dao_fork_block_number()
+            start_block = dao_fork_num - 1
 
             try:
                 headers = await self.peer.requests.get_block_headers(  # type: ignore
@@ -62,13 +64,46 @@ async def ensure_same_side_on_dao_fork(self) -> None:
                 ) from err
 
             if len(headers) != 2:
-                raise DAOForkCheckFailure(
-                    f"{self.peer} failed to return DAO fork check headers"
-                )
+                tip_header = await self._get_tip_header()
+                if tip_header.block_number < dao_fork_num:
+                    self.logger.debug(
+                        f"{self.peer} has tip {tip_header!r}, and returned {headers!r} "
+                        "at DAO fork #{dao_fork_num}. Peer seems to be syncing..."
+                    )
+                    return
+                else:
+                    raise DAOForkCheckFailure(
+                        f"{self.peer} has tip {tip_header!r}, but only returned {headers!r} "
+                        "at DAO fork #{dao_fork_num}. Peer seems to be witholding DAO headers..."
+                    )
             else:
                 parent, header = headers
 
             try:
                 vm_class.validate_header(header, parent, check_seal=True)
             except ValidationError as err:
                 raise DAOForkCheckFailure(f"{self.peer} failed DAO fork check validation: {err}")
+
+    async def _get_tip_header(self) -> BlockHeader:
+        try:
+            headers = await self.peer.requests.get_block_headers(  # type: ignore
+                self.peer.head_hash,
+                max_headers=1,
+                timeout=CHAIN_SPLIT_CHECK_TIMEOUT,
+            )
+
+        except (TimeoutError, PeerConnectionLost) as err:
+            raise DAOForkCheckFailure(
+                f"Timed out waiting for tip header from {self.peer}: {err}"
+            ) from err
+        except ValidationError as err:
+            raise DAOForkCheckFailure(
+                f"Invalid header response for tip header during DAO fork check: {err}"
+            ) from err
+        else:
+            if len(headers) != 1:
+                raise DAOForkCheckFailure(
+                    f"{self.peer} returned {headers!r} when asked for tip"
+                )
+            else:
+                return headers[0]