Replace relevant services logic with a function suite.

Adds HasAllRelevantServices and GetRelevantServices, which check
for NETWORK|WITNESS.

This changes the following:
 * Removes nRelevantServices from CConnman, disconnecting it a bit
   more from protocol-level logic.
 * Replaces our sometimes-connect-to-!WITNESS-nodes logic with
   simply always requiring WITNESS|NETWORK for outbound non-feeler
   connections (feelers still only require NETWORK).
 * This has the added benefit of removing nServicesExpected from
   CNode - instead letting net_processing's VERSION message
   handling simply check HasAllRelevantServices.
 * This implies we believe WITNESS nodes to continue to be a
   significant majority of nodes on the network, but also because
   we cannot sync properly from !WITNESS nodes, it is strange to
   continue using our valuable outbound slots on them.
 * In order to prevent this change from preventing connection to
   -connect= nodes which have !WITNESS, -connect nodes are now
   given the "addnode" flag. This also allows outbound connections
   to !NODE_NETWORK nodes for -connect nodes (which was already true
   of addnodes).
 * Has the (somewhat unintended) consequence of changing one of the
   eviction metrics from the same
   sometimes-connect-to-!WITNESS-nodes metric to requiring
   HasRelevantServices.

This should make NODE_NETWORK_LIMITED much simpler to implement.

1 files changed, 0 insertions, 5 deletions

diff --git a/src/init.cpp b/src/init.cpp
index b46b53ac13..951800f6c2 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -815,7 +815,6 @@ void InitLogging()
 
 namespace { // Variables internal to initialization process only
 
-ServiceFlags nRelevantServices = NODE_NETWORK;
 int nMaxConnections;
 int nUserMaxConnections;
 int nFD;
@@ -1604,9 +1603,6 @@ bool AppInitMain(boost::thread_group& threadGroup, CScheduler& scheduler)
         // Note that setting NODE_WITNESS is never required: the only downside from not
         // doing so is that after activation, no upgraded nodes will fetch from you.
         nLocalServices = ServiceFlags(nLocalServices | NODE_WITNESS);
-        // Only care about others providing witness capabilities if there is a softfork
-        // defined.
-        nRelevantServices = ServiceFlags(nRelevantServices | NODE_WITNESS);
     }
 
     // ********************************************************* Step 10: import blocks
@@ -1656,7 +1652,6 @@ bool AppInitMain(boost::thread_group& threadGroup, CScheduler& scheduler)
 
     CConnman::Options connOptions;
     connOptions.nLocalServices = nLocalServices;
-    connOptions.nRelevantServices = nRelevantServices;
     connOptions.nMaxConnections = nMaxConnections;
     connOptions.nMaxOutbound = std::min(MAX_OUTBOUND_CONNECTIONS, connOptions.nMaxConnections);
     connOptions.nMaxAddnode = MAX_ADDNODE_CONNECTIONS;