From a0a2d6b004cd5c4435a7e0c116cfc6ed5fdffaf8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gr=C3=A9goire=20Henry?= <gregoire.henry@tezos.com>
Date: Sat, 5 May 2018 20:25:57 +0200
Subject: [PATCH] Shell: filter out future block

---
 src/lib_shell/bootstrap_pipeline.ml         | 10 ++++++
 src/lib_shell/distributed_db.ml             | 38 +++++++++++++++------
 src/lib_shell_services/validation_errors.ml |  1 +
 3 files changed, 38 insertions(+), 11 deletions(-)

diff --git a/src/lib_shell/bootstrap_pipeline.ml b/src/lib_shell/bootstrap_pipeline.ml
index 75f52912a..5c3f702b8 100644
--- a/src/lib_shell/bootstrap_pipeline.ml
+++ b/src/lib_shell/bootstrap_pipeline.ml
@@ -61,6 +61,9 @@ let fetch_step pipeline (step : Block_locator.step)  =
           pipeline.chain_db ~peer:pipeline.peer_id
           hash ()
       end >>=? fun header ->
+      fail_unless
+        (Time.(now () >= header.shell.timestamp))
+        (Future_block_header hash) >>=? fun () ->
       lwt_debug "fetched block header %a from peer %a."
         Block_hash.pp_short hash
         P2p_peer.Id.pp_short pipeline.peer_id >>= fun () ->
@@ -99,6 +102,12 @@ let headers_fetch_worker_loop pipeline =
         P2p_peer.Id.pp_short pipeline.peer_id >>= fun () ->
       Lwt_canceler.cancel pipeline.canceler >>= fun () ->
       Lwt.return_unit
+  | Error [ Future_block_header bh ] ->
+      lwt_log_notice "Block locator %a from peer %a contains future blocks."
+        Block_hash.pp_short bh
+        P2p_peer.Id.pp_short pipeline.peer_id >>= fun () ->
+      Lwt_canceler.cancel pipeline.canceler >>= fun () ->
+      Lwt.return_unit
   | Error err ->
       pipeline.errors <- pipeline.errors @ err ;
       lwt_log_error "@[Unexpected error (headers fetch):@ %a@]"
@@ -214,6 +223,7 @@ let create
   Lwt_canceler.on_cancel pipeline.canceler begin fun () ->
     Lwt_pipe.close fetched_blocks ;
     Lwt_pipe.close fetched_headers ;
+    (* TODO proper cleanup of ressources... *)
     Lwt.return_unit
   end ;
   let head, _ = (pipeline.locator : Block_locator.t :> _ * _) in
diff --git a/src/lib_shell/distributed_db.ml b/src/lib_shell/distributed_db.ml
index 67d3cd59c..d77eea659 100644
--- a/src/lib_shell/distributed_db.ml
+++ b/src/lib_shell/distributed_db.ml
@@ -490,12 +490,20 @@ module P2p_reader = struct
         Lwt_list.exists_p
           (State.Block.known_invalid chain_db.chain_state)
           (Block_header.hash head :: hist) >>= fun known_invalid ->
-        if not known_invalid then
-          chain_db.callback.notify_branch state.gid locator
-        else
-          (* Kickban *)
-          P2p.greylist_peer global_db.p2p state.gid;
-        Lwt.return_unit
+        if known_invalid then begin
+          (* TODO Kick *)
+          P2p.greylist_peer global_db.p2p state.gid ;
+          Lwt.return_unit
+        end else if Time.(now () < head.shell.timestamp) then begin
+          (* TODO some penalty *)
+          lwt_log_notice "Received future block %a from peer %a."
+            Block_hash.pp_short (Block_header.hash head)
+            P2p_peer.Id.pp_short state.gid >>= fun () ->
+          Lwt.return_unit
+        end else begin
+          chain_db.callback.notify_branch state.gid locator ;
+          Lwt.return_unit
+        end
 
     | Deactivate chain_id ->
         may_handle state chain_id @@ fun chain_db ->
@@ -533,12 +541,20 @@ module P2p_reader = struct
                so the message is ignored.
                This should probably warrant a reduction of the sender's score. *)
         in
-        if not known_invalid then
-          chain_db.callback.notify_head state.gid header mempool
-        else
-          (* Kickban *)
+        if known_invalid then begin
+          (* TODO Kick *)
           P2p.greylist_peer global_db.p2p state.gid ;
-        Lwt.return_unit
+          Lwt.return_unit
+        end else if Time.(now () < header.shell.timestamp) then begin
+          (* TODO some penalty *)
+          lwt_log_notice "Received future block %a from peer %a."
+            Block_hash.pp_short head
+            P2p_peer.Id.pp_short state.gid >>= fun () ->
+          Lwt.return_unit
+        end else begin
+          chain_db.callback.notify_head state.gid header mempool ;
+          Lwt.return_unit
+        end
 
     | Get_block_headers hashes ->
         Lwt_list.iter_p
diff --git a/src/lib_shell_services/validation_errors.ml b/src/lib_shell_services/validation_errors.ml
index e38f617fc..5331ea787 100644
--- a/src/lib_shell_services/validation_errors.ml
+++ b/src/lib_shell_services/validation_errors.ml
@@ -12,6 +12,7 @@
 type error += Parse_error
 type error += Too_many_operations
 type error += Oversized_operation of { size: int ; max: int }
+type error += Future_block_header of Block_hash.t
 
 let () =
   (* Parse error *)