dns: introduce initial DNS Manager

Signed-off-by: Alejandro Mery <amery@jpi.io>

pkg/dns/record.go

@@ -113,3 +113,83 @@ func (rr *AddrRecord) String() string {
 	_, _ = rr.WriteTo(&buf)
 	return buf.String()
 }
+
+func (mgr *Manager) genRegionsSorted() []string {
+	regions := make([]string, 0, len(mgr.regions))
+	for name := range mgr.regions {
+		regions = append(regions, name)
+	}
+
+	return SortRegions(regions)
+}
+
+func (mgr *Manager) genAllAddrRecords() []AddrRecord {
+	var out []AddrRecord
+
+	cache := make(map[string][]netip.Addr)
+
+	// zones
+	for _, z := range mgr.zones {
+		// hosts
+		s := mgr.genZoneHostRecords(z)
+		out = append(out, s...)
+
+		// zone alias
+		addrs := mgr.genZoneAddresses(z)
+		name := z.Name
+
+		out = append(out, AddrRecord{
+			Name: name + mgr.suffix,
+			Addr: addrs,
+		})
+
+		// and cache for regions
+		cache[name] = addrs
+	}
+
+	for _, name := range mgr.genRegionsSorted() {
+		var addrs []netip.Addr
+
+		for _, z := range mgr.regions[name] {
+			addrs = append(addrs, cache[z]...)
+		}
+
+		rec := AddrRecord{
+			Name: name + mgr.suffix,
+			Addr: addrs,
+		}
+		rec.Sort()
+
+		out = append(out, rec)
+	}
+
+	return out
+}
+
+func (*Manager) genZoneAddresses(z *Zone) []netip.Addr {
+	var out []netip.Addr
+
+	for _, p := range z.Hosts {
+		if p.Active {
+			out = append(out, p.Addrs...)
+		}
+	}
+
+	SortAddrSlice(out)
+	return out
+}
+
+func (mgr *Manager) genZoneHostRecords(z *Zone) []AddrRecord {
+	out := make([]AddrRecord, 0, len(z.Hosts))
+
+	for _, p := range z.Hosts {
+		rec := AddrRecord{
+			Name: p.String() + mgr.suffix,
+			Addr: p.Addrs,
+		}
+		out = append(out, rec)
+	}
+
+	SortAddrRecords(out)
+	return out
+}