root hints, glue record, delegation loop, iterative, ns fallback, timeout, glue record

1 files changed, 55 insertions, 0 deletions

diff --git a/internal/resolver/root.go b/internal/resolver/root.go
new file mode 100644
index 0000000..9dac31c
--- /dev/null
+++ b/internal/resolver/root.go
@@ -0,0 +1,55 @@
+package resolver
+
+import (
+	_ "embed"
+	"github.com/miekg/dns"
+	"strings"
+)
+
+//go:embed named.root
+var rootHintsData []byte
+
+func loadRootServers() []string {
+	var addrs []string
+	seen := make(map[string]bool)
+
+	zp := dns.NewZoneParser(strings.NewReader(string(rootHintsData)), "", "")
+	for {
+		rr, ok := zp.Next()
+		if !ok {
+			break
+		}
+		a, ok := rr.(*dns.A)
+		if !ok {
+			continue
+		}
+		ip := a.A.String()
+		if !seen[ip] {
+			seen[ip] = true
+			addrs = append(addrs, ip)
+		}
+	}
+
+	if err := zp.Err(); err != nil || len(addrs) == 0 {
+		return hardcodedRoots()
+	}
+	return addrs
+}
+
+func hardcodedRoots() []string {
+	return []string{
+		"198.41.0.4",
+		"170.247.170.2",
+		"192.33.4.12",
+		"199.7.91.13",
+		"192.203.230.10",
+		"192.5.5.241",
+		"192.112.36.4",
+		"198.97.190.53",
+		"192.36.148.17",
+		"192.58.128.30",
+		"193.0.14.129",
+		"199.7.83.42",
+		"202.12.27.33",
+	}
+}