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, 8 deletions

diff --git a/src/net.h b/src/net.h
index 905d6eb956..b4873b1e4d 100644
--- a/src/net.h
+++ b/src/net.h
@@ -84,8 +84,6 @@ static const bool DEFAULT_FORCEDNSSEED = false;
 static const size_t DEFAULT_MAXRECEIVEBUFFER = 5 * 1000;
 static const size_t DEFAULT_MAXSENDBUFFER    = 1 * 1000;
 
-static const ServiceFlags REQUIRED_SERVICES = NODE_NETWORK;
-
 // NOTE: When adjusting this, update rpcnet:setban's help ("24h")
 static const unsigned int DEFAULT_MISBEHAVING_BANTIME = 60 * 60 * 24;  // Default 24-hour ban
 
@@ -130,7 +128,6 @@ public:
     struct Options
     {
         ServiceFlags nLocalServices = NODE_NONE;
-        ServiceFlags nRelevantServices = NODE_NONE;
         int nMaxConnections = 0;
         int nMaxOutbound = 0;
         int nMaxAddnode = 0;
@@ -152,7 +149,6 @@ public:
 
     void Init(const Options& connOptions) {
         nLocalServices = connOptions.nLocalServices;
-        nRelevantServices = connOptions.nRelevantServices;
         nMaxConnections = connOptions.nMaxConnections;
         nMaxOutbound = std::min(connOptions.nMaxOutbound, connOptions.nMaxConnections);
         nMaxAddnode = connOptions.nMaxAddnode;
@@ -390,9 +386,6 @@ private:
     /** Services this instance offers */
     ServiceFlags nLocalServices;
 
-    /** Services this instance cares about */
-    ServiceFlags nRelevantServices;
-
     CSemaphore *semOutbound;
     CSemaphore *semAddnode;
     int nMaxConnections;
@@ -585,7 +578,6 @@ class CNode
 public:
     // socket
     std::atomic<ServiceFlags> nServices;
-    ServiceFlags nServicesExpected;
     SOCKET hSocket;
     size_t nSendSize; // total size of all vSendMsg entries
     size_t nSendOffset; // offset inside the first vSendMsg already sent