Implement witness pruning.

include/bitcoin/node/protocols/protocol_block_in_31800.hpp

@@ -41,6 +41,7 @@ class BCN_API protocol_block_in_31800
             session->system_settings().top_checkpoint().height()),
         block_type_(session->network_settings().witness_node() ?
             type_id::witness_block : type_id::block),
+        node_pruned_(session->network_settings().pruned_node()),
         map_(chaser_check::empty_map()),
         network::tracker<protocol_block_in_31800>(session->log)
     {
@@ -84,13 +85,15 @@ class BCN_API protocol_block_in_31800
 
     void restore(const map_ptr& map) NOEXCEPT;
     bool is_under_checkpoint(size_t height) const NOEXCEPT;
+    type_id to_block_type(const database::association& item) const NOEXCEPT;
     void handle_put_hashes(const code& ec, size_t count) NOEXCEPT;
     void handle_get_hashes(const code& ec, const map_ptr& map,
         const job::ptr& job) NOEXCEPT;
 
     // These are thread safe.
     const size_t top_checkpoint_height_;
     const type_id block_type_;
+    const bool node_pruned_;
 
     // These are protected by strand.
     map_ptr map_;

include/bitcoin/node/protocols/protocol_block_out_106.hpp

@@ -36,6 +36,9 @@ class BCN_API protocol_block_out_106
     protocol_block_out_106(const auto& session,
         const network::channel::ptr& channel) NOEXCEPT
       : node::protocol_peer(session, channel),
+        top_checkpoint_height_(
+            session->system_settings().top_checkpoint().height()),
+        node_pruned_(session->network_settings().pruned_node()),
         node_witness_(session->network_settings().witness_node()),
         allow_overlapped_(session->node_settings().allow_overlapped),
         network::tracker<protocol_block_out_106>(session->log)
@@ -73,10 +76,13 @@ class BCN_API protocol_block_out_106
     using inventory_item = network::messages::peer::inventory_item;
     using inventory_items = network::messages::peer::inventory_items;
 
+    bool is_under_checkpoint(const database::header_link& link) NOEXCEPT;
     inventory create_inventory(const get_blocks& locator) const NOEXCEPT;
     void merge_inventory(const inventory_items& items) NOEXCEPT;
 
     // These are thread safe.
+    const size_t top_checkpoint_height_;
+    const bool node_pruned_;
     const bool node_witness_;
     const bool allow_overlapped_;
 

src/protocols/protocol_block_in_31800.cpp

@@ -254,7 +254,7 @@ get_data protocol_block_in_31800::create_get_data(
     // bip144: get_data uses witness type_id but inv does not.
     std::for_each(map.pos_begin(), map.pos_end(), [&](const auto& item) NOEXCEPT
     {
-        data.items.emplace_back(block_type_, item.hash);
+        data.items.emplace_back(to_block_type(item), item.hash);
     });
 
     return data;
@@ -277,8 +277,6 @@ bool protocol_block_in_31800::handle_receive_block(const code& ec,
     const auto& block = message->block;
     const auto hash = block.hash();
     const auto it = map_->find(hash);
-    auto& query = archive();
-
     if (it == map_->end())
     {
         // Allow unrequested block, not counted toward performance.
@@ -287,15 +285,21 @@ bool protocol_block_in_31800::handle_receive_block(const code& ec,
         return true;
     }
 
+    auto& query = archive();
     const auto link = it->link;
     const auto height = it->context.height;
+    const auto checked = is_under_checkpoint(height);
+    const auto bypass = checked || query.is_milestone(link);
+    if (bypass && node_pruned_ && block.is_segregated())
+    {
+        LOGR("Unexpected witness from [" << opposite() << "].");
+        stop(system::error::unexpected_witness);
+        return false;
+    }
 
     // Identify block.
     // ........................................................................
 
-    const auto checked = is_under_checkpoint(height);
-    const auto bypass = checked || query.is_milestone(link);
-
     // Tx commitments and malleation are checked under bypass. Invalidity is
     // only stored when a strong header has been stored, later to be found out
     // as invalid and not malleable. Stored invalidity prevents repeat
@@ -363,11 +367,16 @@ bool protocol_block_in_31800::handle_receive_block(const code& ec,
 // While check could be called here, it's more optimal to defer to validate, as
 // requiring only identity here allows the use of the simplified block_view.
 code protocol_block_in_31800::identify(const chain::block_view& block,
-    const chain::context& ctx, bool) const NOEXCEPT
+    const chain::context& ctx, bool bypass) const NOEXCEPT
 {
-    code ec{};
+    if (const auto ec = block.identify())
+        return ec;
+
+    // Bypass witness commitment check for stripped blocks.
+    if (bypass && node_pruned_)
+        return error::success;
 
-    if (((ec = block.identify())) || ((ec = block.identify(ctx))))
+    if (const auto ec = block.identify(ctx))
         return ec;
 
     return error::success;
@@ -420,14 +429,24 @@ void protocol_block_in_31800::handle_get_hashes(const code& ec,
     POST(send_get_data, map, job);
 }
 
-// checkpoint
+// utility
 // ----------------------------------------------------------------------------
 
 bool protocol_block_in_31800::is_under_checkpoint(size_t height) const NOEXCEPT
 {
     return height <= top_checkpoint_height_;
 }
 
+type_id protocol_block_in_31800::to_block_type(
+    const association& item) const NOEXCEPT
+{
+    const auto stripped = node_pruned_ &&
+        (is_under_checkpoint(item.context.height) ||
+         archive().is_milestone(item.link));
+
+    return stripped ? type_id::block : block_type_;
+}
+
 BC_POP_WARNING()
 BC_POP_WARNING()
 BC_POP_WARNING()

src/protocols/protocol_block_out_106.cpp

@@ -32,9 +32,15 @@ using namespace network;
 using namespace std::chrono;
 using namespace std::placeholders;
 
+BC_PUSH_WARNING(NO_THROW_IN_NOEXCEPT)
 BC_PUSH_WARNING(SMART_PTR_NOT_NEEDED)
 BC_PUSH_WARNING(NO_VALUE_OR_CONST_REF_SHARED_PTR)
 
+// This protocol provides witness support despite 106 being much older than
+// bip144. This is because protocols are splot on the version negotiated in the
+// p2p handshake. Witness is enabled via a service bit. Protocols should also
+// be factored based on relevant service bits but that is not yet implemented.
+
 // start/stop
 // ----------------------------------------------------------------------------
 
@@ -202,17 +208,27 @@ void protocol_block_out_106::send_block(const code& ec) NOEXCEPT
     if (backlog_.empty()) return;
     const auto& item = backlog_.front();
     const auto witness = item.is_witness_type();
-    if (!node_witness_ && witness)
+    if (witness && !node_witness_)
     {
         LOGR("Unsupported witness get_data from [" << opposite() << "].");
         stop(network::error::protocol_violation);
         return;
     }
 
     const auto& query = archive();
-    const auto start = logger::now();
     const auto link = query.to_header(item.hash);
+    if (witness && node_witness_ && node_pruned_ &&
+        (is_under_checkpoint(link) || query.is_milestone(link)))
+    {
+        LOGR("Request of witness for stripped block "
+            << encode_hash(item.hash) << " from [" << opposite() << "].");
+
+        // The peer should not be asking for this block with witness.
+        stop(system::error::not_found);
+        return;
+    }
 
+    const auto start = logger::now();
     node::messages::block out{ query.get_wire_block(link, witness), witness };
     if (out.block_data.empty())
     {
@@ -255,6 +271,20 @@ protocol_block_out_106::inventory protocol_block_out_106::create_inventory(
     );
 }
 
+bool protocol_block_out_106::is_under_checkpoint(
+    const database::header_link& link) NOEXCEPT
+{
+    const auto height = archive().get_height(link);
+    if (height.is_terminal())
+    {
+        fault(database::error::integrity);
+        return false;
+    }
+
+    return height <= top_checkpoint_height_;
+}
+
+BC_POP_WARNING()
 BC_POP_WARNING()
 BC_POP_WARNING()