Merge pull request #11696 from rgacogne/ddist-fix-source-itf

dnsdist: Bind to the requested src interface without a src address
PowerDNS · Jun 22, 2022 · f5e76c2 · f5e76c2
2 parents f2c5372 + 33363b1
commit f5e76c2
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Showing 4 changed files with 43 additions and 32 deletions.
diff --git a/pdns/dnsdistdist/dnsdist-backend.cc b/pdns/dnsdistdist/dnsdist-backend.cc
@@ -58,27 +58,34 @@ bool DownstreamState::reconnect()
     }
     if (!IsAnyAddress(d_config.remote)) {
       fd = SSocket(d_config.remote.sin4.sin_family, SOCK_DGRAM, 0);
-      if (!IsAnyAddress(d_config.sourceAddr)) {
-        SSetsockopt(fd, SOL_SOCKET, SO_REUSEADDR, 1);
-        if (!d_config.sourceItfName.empty()) {
+
 #ifdef SO_BINDTODEVICE
-          int res = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, d_config.sourceItfName.c_str(), d_config.sourceItfName.length());
-          if (res != 0) {
-            infolog("Error setting up the interface on backend socket '%s': %s", d_config.remote.toStringWithPort(), stringerror());
-          }
-#endif
+      if (!d_config.sourceItfName.empty()) {
+        int res = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, d_config.sourceItfName.c_str(), d_config.sourceItfName.length());
+        if (res != 0) {
+          infolog("Error setting up the interface on backend socket '%s': %s", d_config.remote.toStringWithPort(), stringerror());
         }
+      }
+#endif
 
+      if (!IsAnyAddress(d_config.sourceAddr)) {
+        SSetsockopt(fd, SOL_SOCKET, SO_REUSEADDR, 1);
+#ifdef IP_BIND_ADDRESS_NO_PORT
+        if (d_config.ipBindAddrNoPort) {
+          SSetsockopt(fd, SOL_IP, IP_BIND_ADDRESS_NO_PORT, 1);
+        }
+#endif
         SBind(fd, d_config.sourceAddr);
       }
+
       try {
         SConnect(fd, d_config.remote);
         if (sockets.size() > 1) {
           (*mplexer.lock())->addReadFD(fd, [](int, boost::any) {});
         }
         connected = true;
       }
-      catch(const std::runtime_error& error) {
+      catch (const std::runtime_error& error) {
         infolog("Error connecting to new server with address %s: %s", d_config.remote.toStringWithPort(), error.what());
         connected = false;
         break;

diff --git a/pdns/dnsdistdist/dnsdist-discovery.cc b/pdns/dnsdistdist/dnsdist-discovery.cc
@@ -254,19 +254,20 @@ bool ServiceDiscovery::getDiscoveredConfig(const UpgradeableBackend& upgradeable
 
     Socket sock(addr.sin4.sin_family, SOCK_STREAM);
     sock.setNonBlocking();
+
+#ifdef SO_BINDTODEVICE
+    if (!backend->d_config.sourceItfName.empty()) {
+      setsockopt(sock.getHandle(), SOL_SOCKET, SO_BINDTODEVICE, backend->d_config.sourceItfName.c_str(), backend->d_config.sourceItfName.length());
+    }
+#endif
+
     if (!IsAnyAddress(backend->d_config.sourceAddr)) {
       sock.setReuseAddr();
 #ifdef IP_BIND_ADDRESS_NO_PORT
       if (backend->d_config.ipBindAddrNoPort) {
         SSetsockopt(sock.getHandle(), SOL_IP, IP_BIND_ADDRESS_NO_PORT, 1);
       }
 #endif
-
-      if (!backend->d_config.sourceItfName.empty()) {
-#ifdef SO_BINDTODEVICE
-        setsockopt(sock.getHandle(), SOL_SOCKET, SO_BINDTODEVICE, backend->d_config.sourceItfName.c_str(), backend->d_config.sourceItfName.length());
-#endif
-      }
       sock.bind(backend->d_config.sourceAddr);
     }
     sock.connect(addr, backend->d_config.tcpConnectTimeout);

diff --git a/pdns/dnsdistdist/dnsdist-healthchecks.cc b/pdns/dnsdistdist/dnsdist-healthchecks.cc
@@ -368,22 +368,23 @@ bool queueHealthCheck(std::unique_ptr<FDMultiplexer>& mplexer, const std::shared
     Socket sock(ds->d_config.remote.sin4.sin_family, ds->doHealthcheckOverTCP() ? SOCK_STREAM : SOCK_DGRAM);
 
     sock.setNonBlocking();
+
+#ifdef SO_BINDTODEVICE
+    if (!ds->d_config.sourceItfName.empty()) {
+      int res = setsockopt(sock.getHandle(), SOL_SOCKET, SO_BINDTODEVICE, ds->d_config.sourceItfName.c_str(), ds->d_config.sourceItfName.length());
+      if (res != 0 && g_verboseHealthChecks) {
+        infolog("Error setting SO_BINDTODEVICE on the health check socket for backend '%s': %s", ds->getNameWithAddr(), stringerror());
+      }
+    }
+#endif
+
     if (!IsAnyAddress(ds->d_config.sourceAddr)) {
       sock.setReuseAddr();
 #ifdef IP_BIND_ADDRESS_NO_PORT
       if (ds->d_config.ipBindAddrNoPort) {
         SSetsockopt(sock.getHandle(), SOL_IP, IP_BIND_ADDRESS_NO_PORT, 1);
       }
 #endif
-
-      if (!ds->d_config.sourceItfName.empty()) {
-#ifdef SO_BINDTODEVICE
-        int res = setsockopt(sock.getHandle(), SOL_SOCKET, SO_BINDTODEVICE, ds->d_config.sourceItfName.c_str(), ds->d_config.sourceItfName.length());
-        if (res != 0 && g_verboseHealthChecks) {
-          infolog("Error setting SO_BINDTODEVICE on the health check socket for backend '%s': %s", ds->getNameWithAddr(), stringerror());
-        }
-#endif
-      }
       sock.bind(ds->d_config.sourceAddr);
     }
 

diff --git a/pdns/dnsdistdist/dnsdist-tcp-downstream.cc b/pdns/dnsdistdist/dnsdist-tcp-downstream.cc
@@ -76,23 +76,25 @@ bool ConnectionToBackend::reconnect()
       auto socket = std::make_unique<Socket>(d_ds->d_config.remote.sin4.sin_family, SOCK_STREAM, 0);
       DEBUGLOG("result of socket() is "<<socket->getHandle());
 
+#ifdef SO_BINDTODEVICE
+      if (!d_ds->d_config.sourceItfName.empty()) {
+        int res = setsockopt(socket->getHandle(), SOL_SOCKET, SO_BINDTODEVICE, d_ds->d_config.sourceItfName.c_str(), d_ds->d_config.sourceItfName.length());
+        if (res != 0) {
+          vinfolog("Error setting up the interface on backend TCP socket '%s': %s", d_ds->getNameWithAddr(), stringerror());
+        }
+      }
+#endif
+
       if (!IsAnyAddress(d_ds->d_config.sourceAddr)) {
         SSetsockopt(socket->getHandle(), SOL_SOCKET, SO_REUSEADDR, 1);
 #ifdef IP_BIND_ADDRESS_NO_PORT
         if (d_ds->d_config.ipBindAddrNoPort) {
           SSetsockopt(socket->getHandle(), SOL_IP, IP_BIND_ADDRESS_NO_PORT, 1);
         }
-#endif
-#ifdef SO_BINDTODEVICE
-        if (!d_ds->d_config.sourceItfName.empty()) {
-          int res = setsockopt(socket->getHandle(), SOL_SOCKET, SO_BINDTODEVICE, d_ds->d_config.sourceItfName.c_str(), d_ds->d_config.sourceItfName.length());
-          if (res != 0) {
-            vinfolog("Error setting up the interface on backend TCP socket '%s': %s", d_ds->getNameWithAddr(), stringerror());
-          }
-        }
 #endif
         socket->bind(d_ds->d_config.sourceAddr, false);
       }
+
       socket->setNonBlocking();
 
       gettimeofday(&d_connectionStartTime, nullptr);