Implement MCNS v1: custom Go DNS server replacing CoreDNS

Replace the CoreDNS precursor with a purpose-built authoritative DNS server. Zones and records (A, AAAA, CNAME) are stored in SQLite and managed via synchronized gRPC + REST APIs authenticated through MCIAS. Non-authoritative queries are forwarded to upstream resolvers with in-memory caching. Key components: - DNS server (miekg/dns) with authoritative zone handling and forwarding - gRPC + REST management APIs with MCIAS auth (mcdsl integration) - SQLite storage with CNAME exclusivity enforcement and auto SOA serials - 30 tests covering database CRUD, DNS resolution, and caching Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-03-26 18:37:14 -07:00
parent a545fec658
commit f9635578e0
48 changed files with 6015 additions and 87 deletions
--- a/internal/db/zones.go
+++ b/internal/db/zones.go
@@ -0,0 +1,182 @@
+package db
+
+import (
+	"database/sql"
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// Zone represents a DNS zone stored in the database.
+type Zone struct {
+	ID         int64
+	Name       string
+	PrimaryNS  string
+	AdminEmail string
+	Refresh    int
+	Retry      int
+	Expire     int
+	MinimumTTL int
+	Serial     int64
+	CreatedAt  string
+	UpdatedAt  string
+}
+
+// ErrNotFound is returned when a requested resource does not exist.
+var ErrNotFound = errors.New("not found")
+
+// ErrConflict is returned when a write conflicts with existing data.
+var ErrConflict = errors.New("conflict")
+
+// ListZones returns all zones ordered by name.
+func (d *DB) ListZones() ([]Zone, error) {
+	rows, err := d.Query(`SELECT id, name, primary_ns, admin_email, refresh, retry, expire, minimum_ttl, serial, created_at, updated_at FROM zones ORDER BY name`)
+	if err != nil {
+		return nil, fmt.Errorf("list zones: %w", err)
+	}
+	defer rows.Close()
+
+	var zones []Zone
+	for rows.Next() {
+		var z Zone
+		if err := rows.Scan(&z.ID, &z.Name, &z.PrimaryNS, &z.AdminEmail, &z.Refresh, &z.Retry, &z.Expire, &z.MinimumTTL, &z.Serial, &z.CreatedAt, &z.UpdatedAt); err != nil {
+			return nil, fmt.Errorf("scan zone: %w", err)
+		}
+		zones = append(zones, z)
+	}
+	return zones, rows.Err()
+}
+
+// GetZone returns a zone by name (case-insensitive).
+func (d *DB) GetZone(name string) (*Zone, error) {
+	name = strings.ToLower(strings.TrimSuffix(name, "."))
+	var z Zone
+	err := d.QueryRow(`SELECT id, name, primary_ns, admin_email, refresh, retry, expire, minimum_ttl, serial, created_at, updated_at FROM zones WHERE name = ?`, name).
+		Scan(&z.ID, &z.Name, &z.PrimaryNS, &z.AdminEmail, &z.Refresh, &z.Retry, &z.Expire, &z.MinimumTTL, &z.Serial, &z.CreatedAt, &z.UpdatedAt)
+	if errors.Is(err, sql.ErrNoRows) {
+		return nil, ErrNotFound
+	}
+	if err != nil {
+		return nil, fmt.Errorf("get zone: %w", err)
+	}
+	return &z, nil
+}
+
+// GetZoneByID returns a zone by ID.
+func (d *DB) GetZoneByID(id int64) (*Zone, error) {
+	var z Zone
+	err := d.QueryRow(`SELECT id, name, primary_ns, admin_email, refresh, retry, expire, minimum_ttl, serial, created_at, updated_at FROM zones WHERE id = ?`, id).
+		Scan(&z.ID, &z.Name, &z.PrimaryNS, &z.AdminEmail, &z.Refresh, &z.Retry, &z.Expire, &z.MinimumTTL, &z.Serial, &z.CreatedAt, &z.UpdatedAt)
+	if errors.Is(err, sql.ErrNoRows) {
+		return nil, ErrNotFound
+	}
+	if err != nil {
+		return nil, fmt.Errorf("get zone by id: %w", err)
+	}
+	return &z, nil
+}
+
+// CreateZone inserts a new zone and returns it with the generated serial.
+func (d *DB) CreateZone(name, primaryNS, adminEmail string, refresh, retry, expire, minimumTTL int) (*Zone, error) {
+	name = strings.ToLower(strings.TrimSuffix(name, "."))
+	serial := nextSerial(0)
+
+	res, err := d.Exec(`INSERT INTO zones (name, primary_ns, admin_email, refresh, retry, expire, minimum_ttl, serial) VALUES (?, ?, ?, ?, ?, ?, ?, ?)`,
+		name, primaryNS, adminEmail, refresh, retry, expire, minimumTTL, serial)
+	if err != nil {
+		if strings.Contains(err.Error(), "UNIQUE constraint") {
+			return nil, fmt.Errorf("%w: zone %q already exists", ErrConflict, name)
+		}
+		return nil, fmt.Errorf("create zone: %w", err)
+	}
+
+	id, err := res.LastInsertId()
+	if err != nil {
+		return nil, fmt.Errorf("create zone: last insert id: %w", err)
+	}
+
+	return d.GetZoneByID(id)
+}
+
+// UpdateZone updates a zone's SOA parameters and bumps the serial.
+func (d *DB) UpdateZone(name, primaryNS, adminEmail string, refresh, retry, expire, minimumTTL int) (*Zone, error) {
+	name = strings.ToLower(strings.TrimSuffix(name, "."))
+
+	zone, err := d.GetZone(name)
+	if err != nil {
+		return nil, err
+	}
+
+	serial := nextSerial(zone.Serial)
+	now := time.Now().UTC().Format("2006-01-02T15:04:05Z")
+
+	_, err = d.Exec(`UPDATE zones SET primary_ns = ?, admin_email = ?, refresh = ?, retry = ?, expire = ?, minimum_ttl = ?, serial = ?, updated_at = ? WHERE id = ?`,
+		primaryNS, adminEmail, refresh, retry, expire, minimumTTL, serial, now, zone.ID)
+	if err != nil {
+		return nil, fmt.Errorf("update zone: %w", err)
+	}
+
+	return d.GetZoneByID(zone.ID)
+}
+
+// DeleteZone deletes a zone and all its records.
+func (d *DB) DeleteZone(name string) error {
+	name = strings.ToLower(strings.TrimSuffix(name, "."))
+	res, err := d.Exec(`DELETE FROM zones WHERE name = ?`, name)
+	if err != nil {
+		return fmt.Errorf("delete zone: %w", err)
+	}
+	n, err := res.RowsAffected()
+	if err != nil {
+		return fmt.Errorf("delete zone: rows affected: %w", err)
+	}
+	if n == 0 {
+		return ErrNotFound
+	}
+	return nil
+}
+
+// BumpSerial increments the serial for a zone within a transaction.
+func (d *DB) BumpSerial(tx *sql.Tx, zoneID int64) error {
+	var current int64
+	if err := tx.QueryRow(`SELECT serial FROM zones WHERE id = ?`, zoneID).Scan(&current); err != nil {
+		return fmt.Errorf("read serial: %w", err)
+	}
+	serial := nextSerial(current)
+	now := time.Now().UTC().Format("2006-01-02T15:04:05Z")
+	_, err := tx.Exec(`UPDATE zones SET serial = ?, updated_at = ? WHERE id = ?`, serial, now, zoneID)
+	return err
+}
+
+// ZoneNames returns all zone names for the DNS handler.
+func (d *DB) ZoneNames() ([]string, error) {
+	rows, err := d.Query(`SELECT name FROM zones ORDER BY name`)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var names []string
+	for rows.Next() {
+		var name string
+		if err := rows.Scan(&name); err != nil {
+			return nil, err
+		}
+		names = append(names, name)
+	}
+	return names, rows.Err()
+}
+
+// nextSerial computes the next SOA serial in YYYYMMDDNN format.
+func nextSerial(current int64) int64 {
+	today := time.Now().UTC()
+	datePrefix, _ := strconv.ParseInt(today.Format("20060102"), 10, 64)
+	datePrefix *= 100 // YYYYMMDD00
+
+	if current >= datePrefix {
+		return current + 1
+	}
+	return datePrefix + 1
+}