Split dns.go in one file per check

pkg/analyzer/dns_mx.go

@@ -0,0 +1,115 @@
+// This file is part of the happyDeliver (R) project.
+// Copyright (c) 2025 happyDomain
+// Authors: Pierre-Olivier Mercier, et al.
+//
+// This program is offered under a commercial and under the AGPL license.
+// For commercial licensing, contact us at <contact@happydomain.org>.
+//
+// For AGPL licensing:
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package analyzer
+
+import (
+	"context"
+	"fmt"
+
+	"git.happydns.org/happyDeliver/internal/api"
+)
+
+// checkMXRecords looks up MX records for a domain
+func (d *DNSAnalyzer) checkMXRecords(domain string) *[]api.MXRecord {
+	ctx, cancel := context.WithTimeout(context.Background(), d.Timeout)
+	defer cancel()
+
+	mxRecords, err := d.resolver.LookupMX(ctx, domain)
+	if err != nil {
+		return &[]api.MXRecord{
+			{
+				Valid: false,
+				Error: api.PtrTo(fmt.Sprintf("Failed to lookup MX records: %v", err)),
+			},
+		}
+	}
+
+	if len(mxRecords) == 0 {
+		return &[]api.MXRecord{
+			{
+				Valid: false,
+				Error: api.PtrTo("No MX records found"),
+			},
+		}
+	}
+
+	var results []api.MXRecord
+	for _, mx := range mxRecords {
+		results = append(results, api.MXRecord{
+			Host:     mx.Host,
+			Priority: mx.Pref,
+			Valid:    true,
+		})
+	}
+
+	return &results
+}
+
+func (d *DNSAnalyzer) calculateMXScore(results *api.DNSResults) (score int) {
+	// Having valid MX records is critical for email deliverability
+	// From domain MX records (half points) - needed for replies
+	if results.FromMxRecords != nil && len(*results.FromMxRecords) > 0 {
+		hasValidFromMX := false
+		for _, mx := range *results.FromMxRecords {
+			if mx.Valid {
+				hasValidFromMX = true
+				break
+			}
+		}
+		if hasValidFromMX {
+			score += 50
+		}
+	}
+
+	// Return-Path domain MX records (10 points) - needed for bounces
+	if results.RpMxRecords != nil && len(*results.RpMxRecords) > 0 {
+		hasValidRpMX := false
+		for _, mx := range *results.RpMxRecords {
+			if mx.Valid {
+				hasValidRpMX = true
+				break
+			}
+		}
+		if hasValidRpMX {
+			score += 50
+		}
+	} else if results.RpDomain != nil && *results.RpDomain != results.FromDomain {
+		// If Return-Path domain is different but has no MX records, it's a problem
+		// Don't deduct points if RP domain is same as From domain (already checked)
+	} else {
+		// If Return-Path is same as From domain, give full 10 points for RP MX
+		if results.FromMxRecords != nil && len(*results.FromMxRecords) > 0 {
+			hasValidFromMX := false
+			for _, mx := range *results.FromMxRecords {
+				if mx.Valid {
+					hasValidFromMX = true
+					break
+				}
+			}
+			if hasValidFromMX {
+				score += 50
+			}
+		}
+	}
+
+	return
+}