calidns: Fix setting an ECS source of 0

diff --git a/pdns/calidns.cc b/pdns/calidns.cc
index 87bfbe57edbabaa08d8f63d9b319b85e987fbac1..9afdbe93afb0f67714722754172d32445e4e0c04 100644 (file)
--- a/pdns/calidns.cc
+++ b/pdns/calidns.cc
@@ -121,7 +121,7 @@ static ComboAddress getRandomAddressFromRange(const Netmask& ecsRange)
 {
   ComboAddress result = ecsRange.getMaskedNetwork();
   uint8_t bits = ecsRange.getBits();
-  uint32_t mod = 1 << (32 - bits);
+  uint32_t mod = (bits > 0) ? (1 << (32 - bits)) : std::numeric_limits<uint32_t>::max();
   result.sin4.sin_addr.s_addr = result.sin4.sin_addr.s_addr + ntohl(dns_random(mod));
   return result;
 }