SystemD DNS fix:

when dns is port 53 call SetLinKDNS otherwise call SetLinkDNSEx as on older versions of systemd-resolved SetLinkDNSEx is not available.

llarp/router/systemd_resolved.cpp

@@ -87,46 +87,84 @@ namespace llarp
     {
       // This passing address by bytes and using two separate calls for ipv4/ipv6 is gross, but the
       // alternative is to build up a bunch of crap with va_args, which is slightly more gross.
+      const bool isStandardDNSPort = dns.getPort() == 53;
       if (dns.isIPv6())
       {
         auto ipv6 = dns.getIPv6();
         static_assert(sizeof(ipv6) == 16);
         auto* a = reinterpret_cast<const uint8_t*>(&ipv6);
-        resolved_call(
-            bus,
-            "SetLinkDNSEx",
-            "ia(iayqs)",
-            (int32_t)if_ndx,
-            (int)1,             // number of "iayqs"s we are passing
-            (int32_t)AF_INET6,  // network address type
-            (int)16,            // network addr byte size
-            // clang-format off
-            a[0], a[1], a[2],  a[3],  a[4],  a[5],  a[6],  a[7],
-            a[8], a[9], a[10], a[11], a[12], a[13], a[14], a[15], // yuck
-            // clang-format on
-            (uint16_t)dns.getPort(),
-            nullptr  // dns server name (for TLS SNI which we don't care about)
-        );
+        if (isStandardDNSPort)
+        {
+          resolved_call(
+              bus,
+              "SetLinkDNS",
+              "ia(iay)",
+              (int32_t)if_ndx,
+              (int)1,             // number of "iayqs"s we are passing
+              (int32_t)AF_INET6,  // network address type
+              (int)16,            // network addr byte size
+                                  // clang-format off
+              a[0], a[1], a[2],  a[3],  a[4],  a[5],  a[6],  a[7],
+              a[8], a[9], a[10], a[11], a[12], a[13], a[14], a[15] // yuck
+                                  // clang-format on
+          );
+        }
+        else
+        {
+          resolved_call(
+              bus,
+              "SetLinkDNSEx",
+              "ia(iayqs)",
+              (int32_t)if_ndx,
+              (int)1,             // number of "iayqs"s we are passing
+              (int32_t)AF_INET6,  // network address type
+              (int)16,            // network addr byte size
+              // clang-format off
+              a[0], a[1], a[2],  a[3],  a[4],  a[5],  a[6],  a[7],
+              a[8], a[9], a[10], a[11], a[12], a[13], a[14], a[15], // yuck
+              // clang-format on
+              (uint16_t)dns.getPort(),
+              nullptr  // dns server name (for TLS SNI which we don't care about)
+          );
+        }
       }
       else
       {
         auto ipv4 = dns.getIPv4();
         static_assert(sizeof(ipv4) == 4);
         auto* a = reinterpret_cast<const uint8_t*>(&ipv4);
-        resolved_call(
-            bus,
-            "SetLinkDNSEx",
-            "ia(iayqs)",
-            (int32_t)if_ndx,
-            (int)1,            // number of "iayqs"s we are passing
-            (int32_t)AF_INET,  // network address type
-            (int)4,            // network addr byte size
-            // clang-format off
-            a[0], a[1], a[2], a[3], // yuck
-            // clang-format on
-            (uint16_t)dns.getPort(),
-            nullptr  // dns server name (for TLS SNI which we don't care about)
-        );
+        if (isStandardDNSPort)
+        {
+          resolved_call(
+              bus,
+              "SetLinkDNS",
+              "ia(iay)",
+              (int32_t)if_ndx,
+              (int)1,            // number of "iayqs"s we are passing
+              (int32_t)AF_INET,  // network address type
+              (int)4,            // network addr byte size
+                                 // clang-format off
+              a[0], a[1], a[2], a[3] // yuck
+                                 // clang-format on
+          );
+        }
+        else
+        {
+          resolved_call(
+              bus,
+              "SetLinkDNSEx",
+              "ia(iayqs)",
+              (int32_t)if_ndx,
+              (int)1,            // number of "iayqs"s we are passing
+              (int32_t)AF_INET,  // network address type
+              (int)4,            // network addr byte size
+              // clang-format off
+              a[0], a[1], a[2], a[3], // yuck
+              // clang-format on
+              (uint16_t)dns.getPort(),
+              nullptr  // dns server name (for TLS SNI which we don't care about)
+          );
+        }
       }
 
       if (global)