calidns: Fix setting an ECS source of 0

(cherry picked from commit ba770e4f65aefdadc489a169ae66fd20c897162c)

diff --git a/pdns/calidns.cc b/pdns/calidns.cc
index 89886e3a704929968e6b5687dc165e4bde2bb4f2..6a3cf25c592d9c57ce7a927385fef14fddfe4047 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;
 }