Merge pull request #6688 from rgacogne/dnsdist-const-ds-remote

dnsdist: Mark the remote member of DownstreamState as const
PowerDNS · May 29, 2018 · b7bf243 · b7bf243
2 parents c6cbc43 + 7340277
commit b7bf243
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Showing 2 changed files with 16 additions and 7 deletions.
diff --git a/pdns/dnsdist.cc b/pdns/dnsdist.cc
@@ -1088,7 +1088,8 @@ static ssize_t udpClientSendRequestToBackend(DownstreamState* ss, const int sd,
     struct msghdr msgh;
     struct iovec iov;
     char cbuf[256];
-    fillMSGHdr(&msgh, &iov, cbuf, sizeof(cbuf), const_cast<char*>(request), requestLen, &ss->remote);
+    ComboAddress remote(ss->remote);
+    fillMSGHdr(&msgh, &iov, cbuf, sizeof(cbuf), const_cast<char*>(request), requestLen, &remote);
     addCMsgSrcAddr(&msgh, cbuf, &ss->sourceAddr, ss->sourceItf);
     result = sendmsg(sd, &msgh, 0);
   }
@@ -1705,7 +1706,15 @@ try
   }
 
   string reply;
-  sock.recvFrom(reply, ds.remote);
+  ComboAddress from;
+  sock.recvFrom(reply, from);
+
+  /* we are using a connected socket but hey.. */
+  if (from != ds.remote) {
+    if (g_verboseHealthChecks)
+      infolog("Invalid health check response received from %s, expecting one from %s", from.toStringWithPort(), ds.remote.toStringWithPort());
+    return false;
+  }
 
   const dnsheader * responseHeader = reinterpret_cast<const dnsheader *>(reply.c_str());
 

diff --git a/pdns/dnsdist.hh b/pdns/dnsdist.hh
@@ -466,10 +466,10 @@ class TCPClientCollection {
   std::atomic<uint64_t> d_numthreads{0};
   std::atomic<uint64_t> d_pos{0};
   std::atomic<uint64_t> d_queued{0};
-  uint64_t d_maxthreads{0};
+  const uint64_t d_maxthreads{0};
   std::mutex d_mutex;
   int d_singlePipe[2];
-  bool d_useSinglePipe;
+  const bool d_useSinglePipe;
 public:
 
   TCPClientCollection(size_t maxThreads, bool useSinglePipe=false): d_maxthreads(maxThreads), d_singlePipe{-1,-1}, d_useSinglePipe(useSinglePipe)
@@ -537,10 +537,10 @@ struct DownstreamState
   std::mutex connectLock;
   std::unique_ptr<FDMultiplexer> mplexer{nullptr};
   std::thread tid;
-  ComboAddress remote;
+  const ComboAddress remote;
   QPSLimiter qps;
   vector<IDState> idStates;
-  ComboAddress sourceAddr;
+  const ComboAddress sourceAddr;
   checkfunc_t checkFunction;
   DNSName checkName{"a.root-servers.net."};
   QType checkType{QType::A};
@@ -565,7 +565,7 @@ struct DownstreamState
   int tcpConnectTimeout{5};
   int tcpRecvTimeout{30};
   int tcpSendTimeout{30};
-  unsigned int sourceItf{0};
+  const unsigned int sourceItf{0};
   uint16_t retries{5};
   uint16_t xpfRRCode{0};
   uint8_t currentCheckFailures{0};