Feat linux firewall support (#805)

Update the client's engine to apply firewall rules received from the manager (results of ACL policy).

client/firewall/nftables/manager_linux_test.go

@@ -0,0 +1,137 @@
+package nftables
+
+import (
+	"fmt"
+	"net"
+	"net/netip"
+	"testing"
+	"time"
+
+	"github.com/google/nftables"
+	"github.com/google/nftables/expr"
+	"github.com/stretchr/testify/require"
+	"golang.org/x/sys/unix"
+
+	fw "github.com/netbirdio/netbird/client/firewall"
+)
+
+func TestNftablesManager(t *testing.T) {
+	// just check on the local interface
+	manager, err := Create("lo")
+	require.NoError(t, err)
+	time.Sleep(time.Second)
+
+	defer func() {
+		err = manager.Reset()
+		require.NoError(t, err, "failed to reset")
+		time.Sleep(time.Second)
+	}()
+
+	ip := net.ParseIP("100.96.0.1")
+
+	testClient := &nftables.Conn{}
+
+	rule, err := manager.AddFiltering(
+		ip,
+		fw.ProtocolTCP,
+		nil,
+		&fw.Port{Values: []int{53}},
+		fw.RuleDirectionIN,
+		fw.ActionDrop,
+		"",
+	)
+	require.NoError(t, err, "failed to add rule")
+
+	rules, err := testClient.GetRules(manager.tableIPv4, manager.filterInputChainIPv4)
+	require.NoError(t, err, "failed to get rules")
+	// 1 regular rule and other "drop all rule" for the interface
+	require.Len(t, rules, 2, "expected 1 rule")
+
+	ipToAdd, _ := netip.AddrFromSlice(ip)
+	add := ipToAdd.Unmap()
+	expectedExprs := []expr.Any{
+		&expr.Meta{Key: expr.MetaKeyIIFNAME, Register: 1},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     ifname("lo"),
+		},
+		&expr.Payload{
+			DestRegister: 1,
+			Base:         expr.PayloadBaseNetworkHeader,
+			Offset:       uint32(9),
+			Len:          uint32(1),
+		},
+		&expr.Cmp{
+			Register: 1,
+			Op:       expr.CmpOpEq,
+			Data:     []byte{unix.IPPROTO_TCP},
+		},
+		&expr.Payload{
+			DestRegister: 1,
+			Base:         expr.PayloadBaseNetworkHeader,
+			Offset:       12,
+			Len:          4,
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     add.AsSlice(),
+		},
+		&expr.Payload{
+			DestRegister: 1,
+			Base:         expr.PayloadBaseTransportHeader,
+			Offset:       2,
+			Len:          2,
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     []byte{0, 53},
+		},
+		&expr.Verdict{Kind: expr.VerdictDrop},
+	}
+	require.ElementsMatch(t, rules[0].Exprs, expectedExprs, "expected the same expressions")
+
+	err = manager.DeleteRule(rule)
+	require.NoError(t, err, "failed to delete rule")
+
+	rules, err = testClient.GetRules(manager.tableIPv4, manager.filterInputChainIPv4)
+	require.NoError(t, err, "failed to get rules")
+	require.Len(t, rules, 1, "expected 1 rules after deleteion")
+
+	err = manager.Reset()
+	require.NoError(t, err, "failed to reset")
+}
+
+func TestNFtablesCreatePerformance(t *testing.T) {
+	for _, testMax := range []int{10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000} {
+		t.Run(fmt.Sprintf("Testing %d rules", testMax), func(t *testing.T) {
+			// just check on the local interface
+			manager, err := Create("lo")
+			require.NoError(t, err)
+			time.Sleep(time.Second)
+
+			defer func() {
+				if err := manager.Reset(); err != nil {
+					t.Errorf("clear the manager state: %v", err)
+				}
+				time.Sleep(time.Second)
+			}()
+
+			ip := net.ParseIP("10.20.0.100")
+			start := time.Now()
+			for i := 0; i < testMax; i++ {
+				port := &fw.Port{Values: []int{1000 + i}}
+				if i%2 == 0 {
+					_, err = manager.AddFiltering(ip, "tcp", nil, port, fw.RuleDirectionOUT, fw.ActionAccept, "accept HTTP traffic")
+				} else {
+					_, err = manager.AddFiltering(ip, "tcp", nil, port, fw.RuleDirectionIN, fw.ActionAccept, "accept HTTP traffic")
+				}
+
+				require.NoError(t, err, "failed to add rule")
+			}
+			t.Logf("execution avg per rule: %s", time.Since(start)/time.Duration(testMax))
+		})
+	}
+}