Verify that outbound connections have expected services

Author: sipa

src/main.cpp

@@ -4616,6 +4616,15 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
         {
             addrman.SetServices(pfrom->addr, pfrom->nServices);
         }
+        if (pfrom->nServicesExpected & ~pfrom->nServices)
+        {
+            LogPrint("net", "peer=%d does not offer the expected services (%08x offered, %08x expected); disconnecting\n", pfrom->id, pfrom->nServices, pfrom->nServicesExpected);
+            pfrom->PushMessage(NetMsgType::REJECT, strCommand, REJECT_NONSTANDARD,
+                               strprintf("Expected to offer services %08x", pfrom->nServicesExpected));
+            pfrom->fDisconnect = true;
+            return false;
+        }
+
         if (pfrom->nVersion < MIN_PEER_PROTO_VERSION)
         {
             // disconnect from peers older than this proto version

src/net.cpp

@@ -71,6 +71,9 @@ namespace {
 
 const static std::string NET_MESSAGE_COMMAND_OTHER = "*other*";
 
+/** Services this node implementation cares about */
+static const uint64_t nRelevantServices = NODE_NETWORK;
+
 //
 // Global state variables
 //
@@ -409,6 +412,7 @@ CNode* ConnectNode(CAddress addrConnect, const char *pszDest, bool fCountFailure
             vNodes.push_back(pnode);
         }
 
+        pnode->nServicesExpected = addrConnect.nServices & nRelevantServices;
         pnode->nTimeConnected = GetTime();
 
         return pnode;
@@ -2325,6 +2329,7 @@ CNode::CNode(SOCKET hSocketIn, const CAddress& addrIn, const std::string& addrNa
     filterInventoryKnown(50000, 0.000001)
 {
     nServices = 0;
+    nServicesExpected = 0;
     hSocket = hSocketIn;
     nRecvVersion = INIT_PROTO_VERSION;
     nLastSend = 0;

src/net.h

@@ -317,6 +317,7 @@ class CNode
 public:
     // socket
     uint64_t nServices;
+    uint64_t nServicesExpected;
     SOCKET hSocket;
     CDataStream ssSend;
     size_t nSendSize; // total size of all vSendMsg entries