From db2dc7a58cb0a3df58188b748df8e0d04ba76f00 Mon Sep 17 00:00:00 2001
From: Matt Corallo <git@bluematt.me>
Date: Mon, 6 Feb 2017 12:18:51 -0500
Subject: Move CNode::addrLocal access behind locked accessors

---
 src/net.cpp            | 24 ++++++++++++++++++++----
 src/net.h              |  8 +++++++-
 src/net_processing.cpp |  4 ++--
 3 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/src/net.cpp b/src/net.cpp
index 8aa1261984..505eb971c0 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -164,8 +164,9 @@ int GetnScore(const CService& addr)
 // Is our peer's addrLocal potentially useful as an external IP source?
 bool IsPeerAddrLocalGood(CNode *pnode)
 {
-    return fDiscover && pnode->addr.IsRoutable() && pnode->addrLocal.IsRoutable() &&
-           !IsLimited(pnode->addrLocal.GetNetwork());
+    CService addrLocal = pnode->GetAddrLocal();
+    return fDiscover && pnode->addr.IsRoutable() && addrLocal.IsRoutable() &&
+           !IsLimited(addrLocal.GetNetwork());
 }
 
 // pushes our own address to a peer
@@ -180,7 +181,7 @@ void AdvertiseLocal(CNode *pnode)
         if (IsPeerAddrLocalGood(pnode) && (!addrLocal.IsRoutable() ||
              GetRand((GetnScore(addrLocal) > LOCAL_MANUAL) ? 8:2) == 0))
         {
-            addrLocal.SetIP(pnode->addrLocal);
+            addrLocal.SetIP(pnode->GetAddrLocal());
         }
         if (addrLocal.IsRoutable())
         {
@@ -606,6 +607,20 @@ void CNode::MaybeSetAddrName(const std::string& addrNameIn) {
     }
 }
 
+CService CNode::GetAddrLocal() const {
+    LOCK(cs_addrLocal);
+    return addrLocal;
+}
+
+void CNode::SetAddrLocal(const CService& addrLocalIn) {
+    LOCK(cs_addrLocal);
+    if (addrLocal.IsValid()) {
+        error("Addr local already set for node: %i. Refusing to change from %s to %s", id, addrLocal.ToString(), addrLocalIn.ToString());
+    } else {
+        addrLocal = addrLocalIn;
+    }
+}
+
 #undef X
 #define X(name) stats.name = name
 void CNode::copyStats(CNodeStats &stats)
@@ -659,7 +674,8 @@ void CNode::copyStats(CNodeStats &stats)
     stats.dPingWait = (((double)nPingUsecWait) / 1e6);
 
     // Leave string empty if addrLocal invalid (not filled in yet)
-    stats.addrLocal = addrLocal.IsValid() ? addrLocal.ToString() : "";
+    CService addrLocalUnlocked = GetAddrLocal();
+    stats.addrLocal = addrLocalUnlocked.IsValid() ? addrLocalUnlocked.ToString() : "";
 }
 #undef X
 
diff --git a/src/net.h b/src/net.h
index 2cfc74e3d5..29b6a44c88 100644
--- a/src/net.h
+++ b/src/net.h
@@ -590,7 +590,6 @@ public:
     const int64_t nTimeConnected;
     std::atomic<int64_t> nTimeOffset;
     const CAddress addr;
-    CService addrLocal;
     std::atomic<int> nVersion;
     // strSubVer is whatever byte array we read from the wire. However, this field is intended
     // to be printed out, displayed to humans in various forms and so on. So we sanitize it and
@@ -698,6 +697,9 @@ private:
 
     mutable CCriticalSection cs_addrName;
     std::string addrName;
+
+    CService addrLocal;
+    mutable CCriticalSection cs_addrLocal;
 public:
 
     NodeId GetId() const {
@@ -731,6 +733,10 @@ public:
     void SetSendVersion(int nVersionIn);
     int GetSendVersion() const;
 
+    CService GetAddrLocal() const;
+    //! May not be called more than once
+    void SetAddrLocal(const CService& addrLocalIn);
+
     CNode* AddRef()
     {
         nRefCount++;
diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index b0c9b3c71b..7d76aa0b48 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -1274,7 +1274,7 @@ bool static ProcessMessage(CNode* pfrom, const std::string& strCommand, CDataStr
         connman.PushMessage(pfrom, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::VERACK));
 
         pfrom->nServices = nServices;
-        pfrom->addrLocal = addrMe;
+        pfrom->SetAddrLocal(addrMe);
         {
             LOCK(pfrom->cs_SubVer);
             pfrom->strSubVer = strSubVer;
@@ -1315,7 +1315,7 @@ bool static ProcessMessage(CNode* pfrom, const std::string& strCommand, CDataStr
                     LogPrint("net", "ProcessMessages: advertising address %s\n", addr.ToString());
                     pfrom->PushAddress(addr, insecure_rand);
                 } else if (IsPeerAddrLocalGood(pfrom)) {
-                    addr.SetIP(pfrom->addrLocal);
+                    addr.SetIP(addrMe);
                     LogPrint("net", "ProcessMessages: advertising address %s\n", addr.ToString());
                     pfrom->PushAddress(addr, insecure_rand);
                 }
-- 
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