Allow and deny lists per subnet; every option of a DHCP message in words

- A subnet is a deny-list subnet (the default: everyone not denied) or
  an allow-list subnet (only clients allowed or with a reservation);
  the deny list counts in both. Entries are MAC addresses, prefixes
  (aa:bb:cc:*) or client IDs. A refused client gets no answer (DENIED
  in the activity log, with an Allow button) or a NAK on renewal.
  steward access, the subnet's Access tab. Schema migration 7.
- The activity log keeps each message's header fields and options,
  decoded into words (dhcp4.Describe): the parameter request list by
  name, client IDs, lease times. ▸ on an Activity row, steward
  activity show N / --details, GET /events/{id}.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/store/state.go

@@ -25,16 +25,16 @@ func (s *Store) LoadState(ctx context.Context) (*model.State, error) {
 	if st.Settings.Options == nil {
 		st.Settings.Options = []model.OptionValue{}
 	}
-	rows, err := s.db.QueryContext(ctx, `SELECT id, name, interface, prefix, pools, pool_order, address_order, lease_time, options, disabled, comment FROM subnets ORDER BY id`)
+	rows, err := s.db.QueryContext(ctx, `SELECT id, name, interface, prefix, pools, pool_order, address_order, lease_time, options, access, allow_list, deny_list, disabled, comment FROM subnets ORDER BY id`)
 	if err != nil {
 		return nil, err
 	}
 	defer rows.Close()
 	for rows.Next() {
 		sn := &model.Subnet{}
-		var prefix, pools, opts string
+		var prefix, pools, opts, allow, deny string
 		var disabled int
-		if err := rows.Scan(&sn.ID, &sn.Name, &sn.Interface, &prefix, &pools, &sn.PoolOrder, &sn.AddressOrder, &sn.LeaseTime, &opts, &disabled, &sn.Comment); err != nil {
+		if err := rows.Scan(&sn.ID, &sn.Name, &sn.Interface, &prefix, &pools, &sn.PoolOrder, &sn.AddressOrder, &sn.LeaseTime, &opts, &sn.Access, &allow, &deny, &disabled, &sn.Comment); err != nil {
 			return nil, err
 		}
 		sn.Prefix, _ = netip.ParsePrefix(prefix)
@@ -45,6 +45,18 @@ func (s *Store) LoadState(ctx context.Context) (*model.State, error) {
 		if err := json.Unmarshal([]byte(opts), &sn.Options); err != nil {
 			return nil, fmt.Errorf("subnet %d options: %w", sn.ID, err)
 		}
+		if err := json.Unmarshal([]byte(allow), &sn.Allow); err != nil {
+			return nil, fmt.Errorf("subnet %d allow list: %w", sn.ID, err)
+		}
+		if err := json.Unmarshal([]byte(deny), &sn.Deny); err != nil {
+			return nil, fmt.Errorf("subnet %d deny list: %w", sn.ID, err)
+		}
+		if len(sn.Allow) == 0 {
+			sn.Allow = nil
+		}
+		if len(sn.Deny) == 0 {
+			sn.Deny = nil
+		}
 		st.Subnets = append(st.Subnets, sn)
 	}
 	if err := rows.Err(); err != nil {
@@ -146,10 +158,12 @@ func applyChange(ctx context.Context, tx *sql.Tx, c model.Change) error {
 		if err := json.Unmarshal(c.After, &sn); err != nil {
 			return err
 		}
-		_, err := tx.ExecContext(ctx, `INSERT INTO subnets (id, name, interface, prefix, pools, pool_order, address_order, lease_time, options, disabled, comment) VALUES (?,?,?,?,?,?,?,?,?,?,?)
+		_, err := tx.ExecContext(ctx, `INSERT INTO subnets (id, name, interface, prefix, pools, pool_order, address_order, lease_time, options, access, allow_list, deny_list, disabled, comment) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?)
 			ON CONFLICT(id) DO UPDATE SET name = excluded.name, interface = excluded.interface, prefix = excluded.prefix, pools = excluded.pools,
-			pool_order = excluded.pool_order, address_order = excluded.address_order, lease_time = excluded.lease_time, options = excluded.options, disabled = excluded.disabled, comment = excluded.comment`,
-			sn.ID, sn.Name, sn.Interface, sn.Prefix.String(), jsonText(nonNil(sn.Pools)), sn.PoolOrder, sn.AddressOrder, sn.LeaseTime, jsonText(nonNilOpts(sn.Options)), boolInt(sn.Disabled), sn.Comment)
+			pool_order = excluded.pool_order, address_order = excluded.address_order, lease_time = excluded.lease_time, options = excluded.options,
+			access = excluded.access, allow_list = excluded.allow_list, deny_list = excluded.deny_list, disabled = excluded.disabled, comment = excluded.comment`,
+			sn.ID, sn.Name, sn.Interface, sn.Prefix.String(), jsonText(nonNil(sn.Pools)), sn.PoolOrder, sn.AddressOrder, sn.LeaseTime, jsonText(nonNilOpts(sn.Options)),
+			sn.Access, jsonText(nonNilMatches(sn.Allow)), jsonText(nonNilMatches(sn.Deny)), boolInt(sn.Disabled), sn.Comment)
 		return err
 	case model.KindReservation:
 		if c.After == nil {
@@ -176,6 +190,13 @@ func nonNil(p []model.Pool) []model.Pool {
 	return p
 }
 
+func nonNilMatches(m []model.ClientMatch) []model.ClientMatch {
+	if m == nil {
+		return []model.ClientMatch{}
+	}
+	return m
+}
+
 func nonNilOpts(o []model.OptionValue) []model.OptionValue {
 	if o == nil {
 		return []model.OptionValue{}