feat: Swarm.RelayService (circuit v2) (ipfs#146)

* remove the EnableRelayHop option in the SwarmConfig

* add an option to disable the limited relay

* make the relay service resources configurable

* refactor: use custom types

This enables us to swap defaults in go-ipfs without touching the config
file generated during `ipfs init`

ipfs/go-ipfs-config#146 (comment)
ipfs/go-ipfs-config#146 (comment)

* use OptionalDuration in RelayService configuration

* fix: *OptionalInteger with omitempty

This removes null values from the config

* fix: Flag does not need to be a pointer

* refactor: flatten RelayService limits

this simplifies consumer code and removes nil footgun

* docs: clarify different relay types

* feat: flag for ForceReachability mode in libp2p (ipfs#150)

adds Internal.Libp2pForceReachability
needed for sharness tests in ipfs#8522

Co-authored-by: Marcin Rataj <lidel@lidel.org>

Co-authored-by: Marcin Rataj <lidel@lidel.org>

config/internal.go

@@ -1,8 +1,10 @@
 package config
 
 type Internal struct {
-	Bitswap                     *InternalBitswap `json:",omitempty"` // This is omitempty since we are expecting to make changes to all subcomponents of Internal
+	// All marked as omitempty since we are expecting to make changes to all subcomponents of Internal
+	Bitswap                     *InternalBitswap `json:",omitempty"`
 	UnixFSShardingSizeThreshold *OptionalString  `json:",omitempty"`
+	Libp2pForceReachability     *OptionalString  `json:",omitempty"`
 }
 
 type InternalBitswap struct {

config/swarm.go

@@ -16,28 +16,54 @@ type SwarmConfig struct {
 	// DisableRelay explicitly disables the relay transport.
 	//
 	// Deprecated: This flag is deprecated and is overridden by
-	// `Transports.Relay` if specified.
+	// `Swarm.Transports.Relay` if specified.
 	DisableRelay bool `json:",omitempty"`
 
-	// EnableRelayHop makes this node act as a public relay, relaying
-	// traffic between other nodes.
-	EnableRelayHop bool
-
-	// EnableAutoRelay enables the "auto relay" feature.
-	//
-	// When both EnableAutoRelay and EnableRelayHop are set, this go-ipfs node
-	// will advertise itself as a public relay. Otherwise it will find and use
-	// advertised public relays when it determines that it's not reachable
-	// from the public internet.
+	// EnableAutoRelay enables the "auto relay user" feature.
+	// Node will find and use advertised public relays when it determines that
+	// it's not reachable from the public internet.
 	EnableAutoRelay bool
 
+	// RelayService.* controls the "auto relay service" feature.
+	// When enabled, node will provide a limited relay service to other peers.
+	RelayService RelayService
+
 	// Transports contains flags to enable/disable libp2p transports.
 	Transports Transports
 
 	// ConnMgr configures the connection manager.
 	ConnMgr ConnMgr
 }
 
+// RelayService configures the resources of the circuit v2 relay.
+// For every field a reasonable default will be defined in go-ipfs.
+type RelayService struct {
+	// Enables the limited relay (circuit v2 relay).
+	Enabled Flag `json:",omitempty"`
+
+	// ConnectionDurationLimit is the time limit before resetting a relayed connection.
+	ConnectionDurationLimit *OptionalDuration `json:",omitempty"`
+	// ConnectionDataLimit is the limit of data relayed (on each direction) before resetting the connection.
+	ConnectionDataLimit *OptionalInteger `json:",omitempty"`
+
+	// ReservationTTL is the duration of a new (or refreshed reservation).
+	ReservationTTL *OptionalDuration `json:",omitempty"`
+
+	// MaxReservations is the maximum number of active relay slots.
+	MaxReservations *OptionalInteger `json:",omitempty"`
+	// MaxCircuits is the maximum number of open relay connections for each peer; defaults to 16.
+	MaxCircuits *OptionalInteger `json:",omitempty"`
+	// BufferSize is the size of the relayed connection buffers.
+	BufferSize *OptionalInteger `json:",omitempty"`
+
+	// MaxReservationsPerPeer is the maximum number of reservations originating from the same peer.
+	MaxReservationsPerPeer *OptionalInteger `json:",omitempty"`
+	// MaxReservationsPerIP is the maximum number of reservations originating from the same IP address.
+	MaxReservationsPerIP *OptionalInteger `json:",omitempty"`
+	// MaxReservationsPerASN is the maximum number of reservations origination from the same ASN.
+	MaxReservationsPerASN *OptionalInteger `json:",omitempty"`
+}
+
 type Transports struct {
 	// Network specifies the base transports we'll use for dialing. To
 	// listen on a transport, add the transport to your Addresses.Swarm.

config/types.go

@@ -270,16 +270,16 @@ type OptionalInteger struct {
 }
 
 // WithDefault resolves the integer with the given default.
-func (p OptionalInteger) WithDefault(defaultValue int64) (value int64) {
-	if p.value == nil {
+func (p *OptionalInteger) WithDefault(defaultValue int64) (value int64) {
+	if p == nil || p.value == nil {
 		return defaultValue
 	}
 	return *p.value
 }
 
 // IsDefault returns if this is a default optional integer
-func (p OptionalInteger) IsDefault() bool {
-	return p.value == nil
+func (p *OptionalInteger) IsDefault() bool {
+	return p == nil || p.value == nil
 }
 
 func (p OptionalInteger) MarshalJSON() ([]byte, error) {

config/types_test.go

@@ -375,6 +375,7 @@ func TestOptionalInteger(t *testing.T) {
 		}
 	}
 
+	// marshal with omitempty
 	type Foo struct {
 		I *OptionalInteger `json:",omitempty"`
 	}
@@ -386,6 +387,20 @@ func TestOptionalInteger(t *testing.T) {
 	if string(out) != expected {
 		t.Fatal("expected omitempty to omit the optional integer")
 	}
+
+	// unmarshal from omitempty output and get default value
+	var foo2 Foo
+	if err := json.Unmarshal(out, &foo2); err != nil {
+		t.Fatalf("%s failed to unmarshall with %s", string(out), err)
+	}
+	if i := foo2.I.WithDefault(42); i != 42 {
+		t.Fatalf("expected default value to be used, got %d", i)
+	}
+	if !foo2.I.IsDefault() {
+		t.Fatal("expected value to be the default")
+	}
+
+	// test invalid values
 	for _, invalid := range []string{
 		"foo", "-1.1", "1.1", "0.0", "[]",
 	} {