From: Otto Moerbeek <otto.moerbeek@open-xchange.com>
Date: Tue, 5 Mar 2019 15:30:22 +0000 (+0100)
Subject: Set IP(V6)_RECVERR socket option to get notified of more than just
X-Git-Tag: auth-4.2.0-rc1~15^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=refs%2Fpull%2F7540%2Fhead;p=thirdparty%2Fpdns.git

Set IP(V6)_RECVERR socket option to get notified of more than just
port unreachable errors on Linux.

See https://sourceware.org/bugzilla/show_bug.cgi?id=24047
---

diff --git a/pdns/misc.cc b/pdns/misc.cc
index b9863ed966..08c42251cf 100644
--- a/pdns/misc.cc
+++ b/pdns/misc.cc
@@ -1101,6 +1101,22 @@ bool isNonBlocking(int sock)
   return flags & O_NONBLOCK;
 }
 
+bool setReceiveSocketErrors(int sock, int af)
+{
+#ifdef __linux__
+  int tmp = 1, ret;
+  if (af == AF_INET) {
+    ret = setsockopt(sock, IPPROTO_IP, IP_RECVERR, &tmp, sizeof(tmp));
+  } else {
+    ret = setsockopt(sock, IPPROTO_IPV6, IPV6_RECVERR, &tmp, sizeof(tmp));
+  }
+  if (ret < 0) {
+    throw PDNSException(string("Setsockopt failed: ") + strerror(errno));
+  }
+#endif
+  return true;
+}
+
 // Closes a socket.
 int closesocket( int socket )
 {
diff --git a/pdns/misc.hh b/pdns/misc.hh
index f57a010bc6..9adfe35dc4 100644
--- a/pdns/misc.hh
+++ b/pdns/misc.hh
@@ -534,6 +534,7 @@ bool setNonBlocking( int sock );
 bool setTCPNoDelay(int sock);
 bool setReuseAddr(int sock);
 bool isNonBlocking(int sock);
+bool setReceiveSocketErrors(int sock, int af);
 int closesocket(int fd);
 bool setCloseOnExec(int sock);
 uint64_t udpErrorStats(const std::string& str);
diff --git a/pdns/pdns_recursor.cc b/pdns/pdns_recursor.cc
index 1a278125bf..dcbbf88579 100644
--- a/pdns/pdns_recursor.cc
+++ b/pdns/pdns_recursor.cc
@@ -623,6 +623,7 @@ public:
     if(!tries)
       throw PDNSException("Resolver binding to local query client socket on "+sin.toString()+": "+stringerror());
 
+    setReceiveSocketErrors(ret, family);
     setNonBlocking(ret);
     return ret;
   }