checker: split monolithic rule into per-concern rules

checker/rules_any.go

@@ -0,0 +1,62 @@
+package checker
+
+import (
+	"context"
+	"fmt"
+
+	sdk "git.happydns.org/checker-sdk-go/checker"
+)
+
+// anyRFC8482Rule flags nameservers that return the full record set for a
+// qtype=ANY query, instead of the minimal HINFO response recommended by
+// RFC 8482.
+type anyRFC8482Rule struct{}
+
+func (r *anyRFC8482Rule) Name() string { return "ns_any_handled" }
+func (r *anyRFC8482Rule) Description() string {
+	return "Verifies that ANY queries are handled per RFC 8482 (HINFO or minimal answer)"
+}
+
+func (r *anyRFC8482Rule) Evaluate(ctx context.Context, obs sdk.ObservationGetter, _ sdk.CheckerOptions) []sdk.CheckState {
+	report, errSt := loadReport(ctx, obs, "ns_any_error")
+	if errSt != nil {
+		return []sdk.CheckState{*errSt}
+	}
+
+	servers := probedServers(report)
+	if len(servers) == 0 {
+		return []sdk.CheckState{noProbesState("ns_any_skipped")}
+	}
+
+	out := make([]sdk.CheckState, 0, len(servers))
+	for _, srv := range servers {
+		state := sdk.CheckState{
+			Subject: serverLabel(srv),
+			Meta:    serverMeta(srv),
+		}
+		switch {
+		case srv.ANY.Error != "":
+			state.Status = sdk.StatusUnknown
+			state.Code = "ns_any_skipped"
+			state.Message = fmt.Sprintf("query failed: %s", srv.ANY.Error)
+		case srv.ANY.Rcode != "NOERROR":
+			state.Status = sdk.StatusOK
+			state.Code = "ns_any_ok"
+			state.Message = fmt.Sprintf("ANY refused (rcode=%s)", srv.ANY.Rcode)
+		case srv.ANY.HINFOOnly:
+			state.Status = sdk.StatusOK
+			state.Code = "ns_any_ok"
+			state.Message = "RFC 8482 compliant HINFO response"
+		case srv.ANY.AnswerCount == 0:
+			state.Status = sdk.StatusOK
+			state.Code = "ns_any_ok"
+			state.Message = "ANY returned empty answer"
+		default:
+			state.Status = sdk.StatusWarn
+			state.Code = "ns_any_non_compliant"
+			state.Message = fmt.Sprintf("ANY returned %d records (not RFC 8482 compliant)", srv.ANY.AnswerCount)
+		}
+		out = append(out, state)
+	}
+	return out
+}