net: Add CNode::ConnectedThroughNetwork member function

src/net.cpp

@@ -539,6 +539,11 @@ void CNode::SetAddrLocal(const CService& addrLocalIn) {
     }
 }
 
+Network CNode::ConnectedThroughNetwork() const
+{
+    return IsInboundConn() && m_inbound_onion ? NET_ONION : addr.GetNetClass();
+}
+
 #undef X
 #define X(name) stats.name = name
 void CNode::copyStats(CNodeStats &stats, const std::vector<bool> &m_asmap)

src/net.h

@@ -961,6 +961,18 @@ public:
         assert(false);
     }
 
+    /**
+     * Get network the peer connected through.
+     *
+     * Returns Network::NET_ONION for *inbound* onion connections,
+     * and CNetAddr::GetNetClass() otherwise. The latter cannot be used directly
+     * because it doesn't detect the former, and it's not the responsibility of
+     * the CNetAddr class to know the actual network a peer is connected through.
+     *
+     * @return network the peer connected through.
+     */
+    Network ConnectedThroughNetwork() const;
+
 protected:
     mapMsgCmdSize mapSendBytesPerMsgCmd;
     mapMsgCmdSize mapRecvBytesPerMsgCmd GUARDED_BY(cs_vRecv);

src/netaddress.cpp

@@ -629,7 +629,7 @@ uint32_t CNetAddr::GetLinkedIPv4() const
     assert(false);
 }
 
-uint32_t CNetAddr::GetNetClass() const
+Network CNetAddr::GetNetClass() const
 {
     // Make sure that if we return NET_IPV6, then IsIPv6() is true. The callers expect that.
 

src/netaddress.h

@@ -182,7 +182,7 @@ class CNetAddr
         std::string ToStringIP() const;
         uint64_t GetHash() const;
         bool GetInAddr(struct in_addr* pipv4Addr) const;
-        uint32_t GetNetClass() const;
+        Network GetNetClass() const;
 
         //! For IPv4, mapped IPv4, SIIT translated IPv4, Teredo, 6to4 tunneled addresses, return the relevant IPv4 address as a uint32.
         uint32_t GetLinkedIPv4() const;