Add support for IPv6 networks (on Linux clients) (#1459)

* Feat add basic support for IPv6 networks

Newly generated networks automatically generate an IPv6 prefix of size
64 within the ULA address range, devices obtain a randomly generated
address within this prefix.

Currently, this is Linux only and does not yet support all features
(routes currently cause an error).

* Fix firewall configuration for IPv6 networks

* Fix routing configuration for IPv6 networks

* Feat provide info on IPv6 support for specific client to mgmt server

* Feat allow configuration of IPv6 support through API, improve stability

* Feat add IPv6 support to new firewall implementation

* Fix peer list item response not containing IPv6 address

* Fix nftables breaking on IPv6 address change

* Fix build issues for non-linux systems

* Fix intermittent disconnections when IPv6 is enabled

* Fix test issues and make some minor revisions

* Fix some more testing issues

* Fix more CI issues due to IPv6

* Fix more testing issues

* Add inheritance of IPv6 enablement status from groups

* Fix IPv6 events not having associated messages

* Address first review comments regarding IPv6 support

* Fix IPv6 table being created even when IPv6 is disabled

Also improved stability of IPv6 route and firewall handling on client side

* Fix IPv6 routes not being removed

* Fix DNS IPv6 issues, limit IPv6 nameservers to IPv6 peers

* Improve code for IPv6 DNS server selection, add AAAA custom records

* Ensure IPv6 routes can only exist for IPv6 routing peers

* Fix IPv6 network generation randomness

* Fix a bunch of compilation issues and test failures

* Replace method calls that are unavailable in Go 1.21

* Fix nil dereference in cleanUpDefaultForwardRules6

* Fix nil pointer dereference when persisting IPv6 network in sqlite

* Clean up of client-side code changes for IPv6

* Fix nil dereference in rule mangling and compilation issues

* Add a bunch of client-side test cases for IPv6

* Fix IPv6 tests running on unsupported environments

* Fix import cycle in tests

* Add missing method SupportsIPv6() for windows

* Require IPv6 default route for IPv6 tests

* Fix panics in routemanager tests on non-linux

* Fix some more route manager tests concerning IPv6

* Add some final client-side tests

* Add IPv6 tests for management code, small fixes

* Fix linting issues

* Fix small test suite issues

* Fix linter issues and builds on macOS and Windows again

* fix builds for iOS because of IPv6 breakage

client/firewall/create.go

@@ -30,3 +30,9 @@ func NewFirewall(context context.Context, iface IFaceMapper) (firewall.Manager,
 	}
 	return fm, nil
 }
+
+// Returns true if the current firewall implementation supports IPv6.
+// Currently false for anything non-linux.
+func SupportsIPv6() bool {
+	return false
+}

client/firewall/create_linux.go

@@ -70,6 +70,8 @@ func NewFirewall(context context.Context, iface IFaceMapper) (firewall.Manager,
 			return nil, errUsp
 		}
 
+		// Note for devs: When adding IPv6 support to userspace bind, the implementation of AllowNetbird() has to be
+		// adjusted accordingly.
 		if err := fm.AllowNetbird(); err != nil {
 			log.Errorf("failed to allow netbird interface traffic: %v", err)
 		}
@@ -83,6 +85,12 @@ func NewFirewall(context context.Context, iface IFaceMapper) (firewall.Manager,
 	return fm, nil
 }
 
+// Returns true if the current firewall implementation supports IPv6.
+// Currently true if the firewall is nftables.
+func SupportsIPv6() bool {
+	return check() == NFTABLES
+}
+
 // check returns the firewall type based on common lib checks. It returns UNKNOWN if no firewall is found.
 func check() FWType {
 	useIPTABLES := false

client/firewall/iface.go

@@ -6,6 +6,7 @@ import "github.com/netbirdio/netbird/iface"
 type IFaceMapper interface {
 	Name() string
 	Address() iface.WGAddress
+	Address6() *iface.WGAddress
 	IsUserspaceBind() bool
 	SetFilter(iface.PacketFilter) error
 }

client/firewall/iptables/manager_linux.go

@@ -24,6 +24,14 @@ type Manager struct {
 	router     *routerManager
 }
 
+func (m *Manager) ResetV6Firewall() error {
+	return nil
+}
+
+func (m *Manager) V6Active() bool {
+	return false
+}
+
 // iFaceMapper defines subset methods of interface required for manager
 type iFaceMapper interface {
 	Name() string

client/firewall/iptables/router_linux_test.go

@@ -73,6 +73,9 @@ func TestIptablesManager_InsertRoutingRules(t *testing.T) {
 
 	for _, testCase := range test.InsertRuleTestCases {
 		t.Run(testCase.Name, func(t *testing.T) {
+			if testCase.IsV6 {
+				t.Skip("Environment does not support IPv6, skipping IPv6 test...")
+			}
 			iptablesClient, err := iptables.NewWithProtocol(iptables.ProtocolIPv4)
 			require.NoError(t, err, "failed to init iptables client")
 
@@ -154,6 +157,9 @@ func TestIptablesManager_RemoveRoutingRules(t *testing.T) {
 
 	for _, testCase := range test.RemoveRuleTestCases {
 		t.Run(testCase.Name, func(t *testing.T) {
+			if testCase.IsV6 {
+				t.Skip("Environment does not support IPv6, skipping IPv6 test...")
+			}
 			iptablesClient, _ := iptables.NewWithProtocol(iptables.ProtocolIPv4)
 
 			manager, err := newRouterManager(context.TODO(), iptablesClient)

client/firewall/manager/firewall.go

@@ -76,6 +76,13 @@ type Manager interface {
 	// RemoveRoutingRules removes a routing firewall rule
 	RemoveRoutingRules(pair RouterPair) error
 
+	// ResetV6Firewall makes changes to the firewall to adapt to the IP address changes.
+	// It is expected that after calling this method ApplyFiltering will be called to re-add the firewall rules.
+	ResetV6Firewall() error
+
+	// V6Active returns whether IPv6 rules should/may be created by upper layers.
+	V6Active() bool
+
 	// Reset firewall to the default state
 	Reset() error