package bridge

import (
	"bytes"
	"net"
	"syscall"
	"testing"

	"github.com/docker/docker/errdefs"
	"github.com/docker/docker/internal/nlwrap"
	"github.com/docker/docker/internal/testutils/netnsutils"
	"github.com/docker/docker/libnetwork/netutils"
	"gotest.tools/v3/assert"
	is "gotest.tools/v3/assert/cmp"
)

func TestSetupNewBridge(t *testing.T) {
	defer netnsutils.SetupTestOSContext(t)()

	nh, err := nlwrap.NewHandle()
	if err != nil {
		t.Fatal(err)
	}
	defer nh.Close()

	config := &networkConfiguration{BridgeName: DefaultBridgeName}
	br := &bridgeInterface{nlh: nh}

	if err := setupDevice(config, br); err != nil {
		t.Fatalf("Bridge creation failed: %v", err)
	}
	if br.Link == nil {
		t.Fatal("bridgeInterface link is nil (expected valid link)")
	}
	if _, err := nh.LinkByName(DefaultBridgeName); err != nil {
		t.Fatalf("Failed to retrieve bridge device: %v", err)
	}
	if br.Link.Attrs().Flags&net.FlagUp == net.FlagUp {
		t.Fatal("bridgeInterface should be created down")
	}
}

func TestSetupNewNonDefaultBridge(t *testing.T) {
	defer netnsutils.SetupTestOSContext(t)()

	nh, err := nlwrap.NewHandle()
	assert.NilError(t, err)
	defer nh.Close()

	config := &networkConfiguration{BridgeName: "test0", DefaultBridge: true}
	br := &bridgeInterface{nlh: nh}

	err = setupDevice(config, br)
	assert.Check(t, is.Error(err, "bridge device with non default name test0 must be created manually"))
	assert.Check(t, is.ErrorType(err, errdefs.IsForbidden))
}

func TestSetupDeviceUp(t *testing.T) {
	defer netnsutils.SetupTestOSContext(t)()

	nh, err := nlwrap.NewHandle()
	if err != nil {
		t.Fatal(err)
	}
	defer nh.Close()

	config := &networkConfiguration{BridgeName: DefaultBridgeName}
	br := &bridgeInterface{nlh: nh}

	if err := setupDevice(config, br); err != nil {
		t.Fatalf("Bridge creation failed: %v", err)
	}
	if err := setupDeviceUp(config, br); err != nil {
		t.Fatalf("Failed to up bridge device: %v", err)
	}

	lnk, _ := nh.LinkByName(DefaultBridgeName)
	if lnk.Attrs().Flags&net.FlagUp != net.FlagUp {
		t.Fatal("bridgeInterface should be up")
	}
}

func TestGenerateRandomMAC(t *testing.T) {
	defer netnsutils.SetupTestOSContext(t)()

	mac1 := netutils.GenerateRandomMAC()
	mac2 := netutils.GenerateRandomMAC()
	if bytes.Equal(mac1, mac2) {
		t.Fatalf("Generated twice the same MAC address %v", mac1)
	}
}

// TestMTUBiggerThan1500 tests that setting an MTU bigger than 1500 succeeds.
// Since v4.17, the kernel allows setting an MTU bigger than 1500 on a bridge
// device even if there's no links attached yet. Relevant kernel commit: [1].
//
// [1]: https://github.com/torvalds/linux/commit/804b854d374e39f5f8bff9638fd274b9a9ca7d33
func TestMTUBiggerThan1500(t *testing.T) {
	defer netnsutils.SetupTestOSContext(t)()

	nh, err := nlwrap.NewHandle()
	if err != nil {
		t.Fatal(err)
	}
	defer nh.Close()

	config := &networkConfiguration{BridgeName: DefaultBridgeName, Mtu: 9000}
	br := &bridgeInterface{nlh: nh}

	assert.NilError(t, setupDevice(config, br))
	assert.NilError(t, setupMTU(config, br))
}

// TestMTUBiggerThan64K tests that setting an MTU bigger than 64k fails
// properly. The kernel caps the MTU at this value -- see [1].
//
// [1]: https://github.com/torvalds/linux/blob/a446e965a188ee8f745859e63ce046fe98577d45/net/bridge/br_device.c#L527
func TestMTUBiggerThan64K(t *testing.T) {
	defer netnsutils.SetupTestOSContext(t)()

	nh, err := nlwrap.NewHandle()
	if err != nil {
		t.Fatal(err)
	}
	defer nh.Close()

	config := &networkConfiguration{BridgeName: DefaultBridgeName, Mtu: 65536}
	br := &bridgeInterface{nlh: nh}

	assert.NilError(t, setupDevice(config, br))
	assert.ErrorIs(t, setupMTU(config, br), syscall.EINVAL)
}
