dhcpsvc: imp code, docs

internal/dhcpsvc/database.go

@@ -6,10 +6,12 @@ import (
 
 // Database is the interface for storing DHCP leases.
 type Database interface {
-	// Load loads leases from the database.  It must be safe for concurrent use.
+	// Load loads leases from the database.  If err is not nil, leases must be
+	// nil.  It must be safe for concurrent use.
 	Load(ctx context.Context) (leases []*Lease, err error)
 
-	// Store stores leases to the database.  It must be safe for concurrent use.
+	// Store stores leases to the database.  leases must be valid.  It must be
+	// safe for concurrent use.
 	Store(ctx context.Context, leases []*Lease) (err error)
 }
 

internal/dhcpsvc/handler4_test.go

@@ -223,6 +223,7 @@ func TestDHCPServer_ServeEther4_release(t *testing.T) {
 	}
 }
 
+// TODO(e.burkov):  Increase maintainability index.
 func TestDHCPServer_ServeEther4_requestSelecting(t *testing.T) {
 	t.Parallel()
 

internal/dhcpsvc/handler6_test.go

@@ -54,6 +54,7 @@ var (
 	testIPv6Static = netip.MustParseAddr("2001:db8::65")
 )
 
+// TODO(e.burkov):  Increase maintainability index.
 func TestDHCPServer_ServeEther6_solicit(t *testing.T) {
 	t.Parallel()
 
@@ -215,6 +216,8 @@ func TestDHCPServer_ServeEther6_solicit(t *testing.T) {
 
 // TODO(e.burkov):  Add tests for REQUEST causing errors.  This would require a
 // custom implementation of the address checker at least.
+//
+// TODO(e.burkov):  Increase maintainability index.
 func TestDHCPServer_ServeEther6_request(t *testing.T) {
 	t.Parallel()
 

internal/dhcpsvc/jsondatabase.go

@@ -38,14 +38,25 @@ type jsonLeasesData struct {
 //
 // TODO(e.burkov):  Migrate to add DUID and IAID fields for DHCPv6 leases.
 type jsonLease struct {
-	Expiry   string     `json:"expires"`
+	// Expiry is the expiration time of the lease in RFC 3339 format.  It is
-	IP       netip.Addr `json:"ip"`
+	// empty for static leases.
-	Hostname string     `json:"hostname"`
+	Expiry string `json:"expires"`
-	HWAddr   string     `json:"mac"`
+
-	IsStatic bool       `json:"static"`
+	// IP is the IP address leased to the client.  It must not be empty.
+	IP netip.Addr `json:"ip"`
+
+	// Hostname is the hostname of the client.
+	Hostname string `json:"hostname"`
+
+	// HWAddr is the MAC address of the client.  It must be a valid hardware
+	// address string according to [netutil.IsValidMACString].
+	HWAddr string `json:"mac"`
+
+	// IsStatic defines if the lease is static.
+	IsStatic bool `json:"static"`
 }
 
-// compareNames returns the result of comparing the hostnames of dl and other
+// compareNames returns the result of comparing the hostnames of jl and other
 // lexicographically.
 func (jl *jsonLease) compareNames(other *jsonLease) (res int) {
 	return strings.Compare(jl.Hostname, other.Hostname)
@@ -71,7 +82,7 @@ func toJSONLease(l *Lease) (jl *jsonLease) {
 	}
 }
 
-// toInternal converts dl to *Lease.
+// toInternal converts jl to *Lease.
 func (jl *jsonLease) toInternal() (l *Lease, err error) {
 	mac, err := net.ParseMAC(jl.HWAddr)
 	if err != nil {

internal/dhcpsvc/leaseindex.go

@@ -186,11 +186,7 @@ func (idx *leaseIndex) dbLoad(
 ) (err error) {
 	leases, err := idx.database.Load(ctx)
 	if err != nil {
-		if leases == nil {
+		return fmt.Errorf("loading leases: %w", err)
-			return fmt.Errorf("loading leases: %w", err)
-		}
-
-		logger.ErrorContext(ctx, "loading leases", slogutil.KeyError, err)
 	}
 
 	idx.addDBLeases(ctx, logger, leases, ifaces4, ifaces6)