Introduce whitelisted peers.

This adds a -whitelist option to specify subnet ranges from which peers
that connect are whitelisted. In addition, there is a -whitebind option
which works like -bind, except peers connecting to it are also
whitelisted (allowing a separate listen port for trusted connections).

Being whitelisted has two effects (for now):
* They are immune to DoS disconnection/banning.
* Transactions they broadcast (which are valid) are always relayed,
  even if they were already in the mempool. This means that a node
  can function as a gateway for a local network, and that rebroadcasts
  from the local network will work as expected.

Whitelisting replaces the magic exemption localhost had for DoS
disconnection (local addresses are still never banned, though), which
implied hidden service connects (from a localhost Tor node) were
incorrectly immune to DoS disconnection as well. This old
behaviour is removed for that reason, but can be restored using
-whitelist=127.0.0.1 or -whitelist=::1 can be specified. -whitebind
is safer to use in case non-trusted localhost connections are expected
(like hidden services).

1 files changed, 12 insertions, 1 deletions

diff --git a/src/net.h b/src/net.h
index c2a0416455..4e42a1eeb2 100644
--- a/src/net.h
+++ b/src/net.h
@@ -64,7 +64,7 @@ CNode* ConnectNode(CAddress addrConnect, const char *pszDest = NULL);
 bool OpenNetworkConnection(const CAddress& addrConnect, CSemaphoreGrant *grantOutbound = NULL, const char *strDest = NULL, bool fOneShot = false);
 void MapPort(bool fUseUPnP);
 unsigned short GetListenPort();
-bool BindListenPort(const CService &bindAddr, std::string& strError);
+bool BindListenPort(const CService &bindAddr, std::string& strError, bool fWhitelisted = false);
 void StartNode(boost::thread_group& threadGroup);
 bool StopNode();
 void SocketSendData(CNode *pnode);
@@ -154,6 +154,7 @@ public:
     uint64_t nSendBytes;
     uint64_t nRecvBytes;
     bool fSyncNode;
+    bool fWhitelisted;
     double dPingTime;
     double dPingWait;
     std::string addrLocal;
@@ -236,6 +237,7 @@ public:
     // store the sanitized version in cleanSubVer. The original should be used when dealing with
     // the network or wire types and the cleaned string used when displayed or logged.
     std::string strSubVer, cleanSubVer;
+    bool fWhitelisted; // This peer can bypass DoS banning.
     bool fOneShot;
     bool fClient;
     bool fInbound;
@@ -259,6 +261,11 @@ protected:
     static std::map<CNetAddr, int64_t> setBanned;
     static CCriticalSection cs_setBanned;
 
+    // Whitelisted ranges. Any node connecting from these is automatically
+    // whitelisted (as well as those connecting to whitelisted binds).
+    static std::vector<CSubNet> vWhitelistedRange;
+    static CCriticalSection cs_vWhitelistedRange;
+
     // Basic fuzz-testing
     void Fuzz(int nChance); // modifies ssSend
 
@@ -305,6 +312,7 @@ public:
         addrName = addrNameIn == "" ? addr.ToStringIPPort() : addrNameIn;
         nVersion = 0;
         strSubVer = "";
+        fWhitelisted = false;
         fOneShot = false;
         fClient = false; // set by version message
         fInbound = fInboundIn;
@@ -720,6 +728,9 @@ public:
     static bool Ban(const CNetAddr &ip);
     void copyStats(CNodeStats &stats);
 
+    static bool IsWhitelistedRange(const CNetAddr &ip);
+    static void AddWhitelistedRange(const CSubNet &subnet);
+
     // Network stats
     static void RecordBytesRecv(uint64_t bytes);
     static void RecordBytesSent(uint64_t bytes);