Add NODE_BLOOM service bit and bump protocol version

Lets nodes advertise that they offer bloom filter support explicitly.
The protocol version bump allows SPV nodes to assume that NODE_BLOOM is
set if NODE_NETWORK is set for pre-170004 nodes.

Also adds an option to turn bloom filter support off for nodes which
advertise a version number >= 170004. Nodes attempting to use bloom
filters on such protocol versions are banned, and a later upgade
should drop nodes of an older version which attempt to use bloom
filters.

Much code stolen from Peter Todd.

Zcash: Implements Zcash equivalent of BIP 111; deploys with Overwinter

src/init.cpp

@@ -1025,6 +1025,9 @@ bool AppInit2(boost::thread_group& threadGroup, CScheduler& scheduler)
     // Option to startup with mocktime set (used for regression testing):
     SetMockTime(GetArg("-mocktime", 0)); // SetMockTime(0) is a no-op
 
+    if (GetBoolArg("-peerbloomfilters", true))
+        nLocalServices |= NODE_BLOOM;
+
 #ifdef ENABLE_MINING
     if (mapArgs.count("-mineraddress")) {
         CBitcoinAddress addr;

src/main.cpp

@@ -5498,6 +5498,21 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
     }
 
 
+    else if (!(nLocalServices & NODE_BLOOM) &&
+              (strCommand == "filterload" ||
+               strCommand == "filteradd" ||
+               strCommand == "filterclear") &&
+              //TODO: Remove this line after reasonable network upgrade
+              pfrom->nVersion >= NO_BLOOM_VERSION)
+    {
+        if (pfrom->nVersion >= NO_BLOOM_VERSION)
+            Misbehaving(pfrom->GetId(), 100);
+        //TODO: Enable this after reasonable network upgrade
+        //else
+        //    pfrom->fDisconnect = true;
+    }
+
+
     else if (strCommand == "filterload")
     {
         CBloomFilter filter;

src/protocol.h

@@ -71,6 +71,10 @@ enum {
     // set by all Bitcoin Core nodes, and is unset by SPV clients or other peers that just want
     // network services but don't provide them.
     NODE_NETWORK = (1 << 0),
+    // NODE_BLOOM means the node is capable and willing to handle bloom-filtered connections.
+    // Zcash nodes used to support this by default, without advertising this bit,
+    // but no longer do as of protocol version 170004 (= NO_BLOOM_VERSION)
+    NODE_BLOOM = (1 << 2),
 
     // Bits 24-31 are reserved for temporary experiments. Just pick a bit that
     // isn't getting used, or one not being used much, and notify the

src/version.h

@@ -9,7 +9,7 @@
  * network protocol versioning
  */
 
-static const int PROTOCOL_VERSION = 170003;
+static const int PROTOCOL_VERSION = 170004;
 
 //! initial proto version, to be increased after version/verack negotiation
 static const int INIT_PROTO_VERSION = 209;
@@ -30,4 +30,7 @@ static const int BIP0031_VERSION = 60000;
 //! "mempool" command, enhanced "getdata" behavior starts with this version
 static const int MEMPOOL_GD_VERSION = 60002;
 
+//! "filter*" commands are disabled without NODE_BLOOM after and including this version
+static const int NO_BLOOM_VERSION = 170004;
+
 #endif // BITCOIN_VERSION_H