src/connectivity/network/netstack/fuchsia_net_stack.go

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

//go:build !build_with_native_toolchain
// +build !build_with_native_toolchain

package netstack

import (
	"errors"
	"fmt"
	"sort"
	"sync/atomic"
	"syscall/zx"
	"syscall/zx/fidl"

	syslog "go.fuchsia.dev/fuchsia/src/lib/syslog/go"

	"go.fuchsia.dev/fuchsia/src/connectivity/network/netstack/fidlconv"
	"go.fuchsia.dev/fuchsia/src/connectivity/network/netstack/link/eth"
	"go.fuchsia.dev/fuchsia/src/connectivity/network/netstack/routes"

	fidlethernet "fidl/fuchsia/hardware/ethernet"
	"fidl/fuchsia/net"
	"fidl/fuchsia/net/name"
	"fidl/fuchsia/net/stack"
	"fidl/fuchsia/netstack"

	"gvisor.dev/gvisor/pkg/tcpip"
	"gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
	"gvisor.dev/gvisor/pkg/tcpip/network/ipv6"
	tcpipstack "gvisor.dev/gvisor/pkg/tcpip/stack"
)

var _ stack.StackWithCtx = (*stackImpl)(nil)

type stackImpl struct {
	ns          *Netstack
	dnsWatchers *dnsServerWatcherCollection
}

func getInterfaceInfo(nicInfo tcpipstack.NICInfo) stack.InterfaceInfo {
	ifs := nicInfo.Context.(*ifState)
	ifs.mu.Lock()
	defer ifs.mu.Unlock()

	administrativeStatus := stack.AdministrativeStatusDisabled
	if ifs.mu.adminUp {
		administrativeStatus = stack.AdministrativeStatusEnabled
	}
	physicalStatus := stack.PhysicalStatusDown
	if ifs.LinkOnlineLocked() {
		physicalStatus = stack.PhysicalStatusUp
	}

	addrs := make([]net.Subnet, 0, len(nicInfo.ProtocolAddresses))
	for _, a := range nicInfo.ProtocolAddresses {
		if a.Protocol != ipv4.ProtocolNumber && a.Protocol != ipv6.ProtocolNumber {
			continue
		}
		addrs = append(addrs, net.Subnet{
			Addr:      fidlconv.ToNetIpAddress(a.AddressWithPrefix.Address),
			PrefixLen: uint8(a.AddressWithPrefix.PrefixLen),
		})
	}

	var features fidlethernet.Features
	if ifs.endpoint.Capabilities()&tcpipstack.CapabilityLoopback != 0 {
		features |= fidlethernet.FeaturesLoopback
	}

	var topopath, filepath string
	if client, ok := ifs.controller.(*eth.Client); ok {
		topopath = client.Topopath()
		filepath = client.Filepath()
		features |= client.Info.Features
	}

	mac := &fidlethernet.MacAddress{}
	copy(mac.Octets[:], ifs.endpoint.LinkAddress())

	return stack.InterfaceInfo{
		Id: uint64(ifs.nicid),
		Properties: stack.InterfaceProperties{
			Name:                 nicInfo.Name,
			Topopath:             topopath,
			Filepath:             filepath,
			Mac:                  mac,
			Mtu:                  ifs.endpoint.MTU(),
			AdministrativeStatus: administrativeStatus,
			PhysicalStatus:       physicalStatus,
			Features:             features,
			Addresses:            addrs,
		},
	}
}

func (ns *Netstack) getNetInterfaces() []stack.InterfaceInfo {
	nicInfos := ns.stack.NICInfo()
	out := make([]stack.InterfaceInfo, 0, len(nicInfos))
	for _, nicInfo := range nicInfos {
		out = append(out, getInterfaceInfo(nicInfo))
	}

	sort.Slice(out, func(i, j int) bool {
		return out[i].Id < out[j].Id
	})
	return out
}

func (ns *Netstack) delInterface(id uint64) stack.StackDelEthernetInterfaceResult {
	var result stack.StackDelEthernetInterfaceResult

	if nicInfo, ok := ns.stack.NICInfo()[tcpip.NICID(id)]; ok {
		nicInfo.Context.(*ifState).RemoveByUser()
		result.SetResponse(stack.StackDelEthernetInterfaceResponse{})
	} else {
		result.SetErr(stack.ErrorNotFound)
	}

	return result
}

func (ns *Netstack) getInterface(id uint64) stack.StackGetInterfaceInfoResult {
	var result stack.StackGetInterfaceInfoResult

	nicInfo, ok := ns.stack.NICInfo()[tcpip.NICID(id)]
	if !ok {
		result.SetErr(stack.ErrorNotFound)
		return result
	}

	result.SetResponse(stack.StackGetInterfaceInfoResponse{
		Info: getInterfaceInfo(nicInfo),
	})
	return result
}

func (ns *Netstack) enableInterface(id uint64) stack.StackEnableInterfaceResult {
	var result stack.StackEnableInterfaceResult

	nicInfo, ok := ns.stack.NICInfo()[tcpip.NICID(id)]
	if !ok {
		result.SetErr(stack.ErrorNotFound)
		return result
	}

	if err := nicInfo.Context.(*ifState).Up(); err != nil {
		_ = syslog.Errorf("ifs.Up() failed (NIC %d): %s", id, err)
		result.SetErr(stack.ErrorInternal)
		return result
	}

	result.SetResponse(stack.StackEnableInterfaceResponse{})
	return result
}

func (ns *Netstack) disableInterface(id uint64) stack.StackDisableInterfaceResult {
	var result stack.StackDisableInterfaceResult

	nicInfo, ok := ns.stack.NICInfo()[tcpip.NICID(id)]
	if !ok {
		result.SetErr(stack.ErrorNotFound)
		return result
	}

	if err := nicInfo.Context.(*ifState).Down(); err != nil {
		_ = syslog.Errorf("ifs.Down() failed (NIC %d): %s", id, err)
		result.SetErr(stack.ErrorInternal)
		return result
	}

	result.SetResponse(stack.StackDisableInterfaceResponse{})
	return result
}

func toProtocolAddr(ifAddr net.Subnet) tcpip.ProtocolAddress {
	protocolAddr := tcpip.ProtocolAddress{
		AddressWithPrefix: tcpip.AddressWithPrefix{
			PrefixLen: int(ifAddr.PrefixLen),
		},
	}

	switch typ := ifAddr.Addr.Which(); typ {
	case net.IpAddressIpv4:
		protocolAddr.Protocol = ipv4.ProtocolNumber
		protocolAddr.AddressWithPrefix.Address = tcpip.Address(ifAddr.Addr.Ipv4.Addr[:])
	case net.IpAddressIpv6:
		protocolAddr.Protocol = ipv6.ProtocolNumber
		protocolAddr.AddressWithPrefix.Address = tcpip.Address(ifAddr.Addr.Ipv6.Addr[:])
	default:
		panic(fmt.Sprintf("unknown IpAddress type %d", typ))
	}
	return protocolAddr
}

func (ns *Netstack) addInterfaceAddr(id uint64, ifAddr net.Subnet) stack.StackAddInterfaceAddressResult {
	var result stack.StackAddInterfaceAddressResult

	protocolAddr := toProtocolAddr(ifAddr)
	if protocolAddr.AddressWithPrefix.PrefixLen > 8*len(protocolAddr.AddressWithPrefix.Address) {
		result.SetErr(stack.ErrorInvalidArgs)
		return result
	}

	switch status := ns.addInterfaceAddress(tcpip.NICID(id), protocolAddr, true /* addRoute */); status {
	case zx.ErrOk:
		result.SetResponse(stack.StackAddInterfaceAddressResponse{})
		return result
	case zx.ErrNotFound:
		result.SetErr(stack.ErrorNotFound)
		return result
	case zx.ErrAlreadyExists:
		_ = syslog.Warnf("(*Netstack).addInterfaceAddr(%s) failed (NIC %d): %s", protocolAddr.AddressWithPrefix, id, status)
		result.SetErr(stack.ErrorAlreadyExists)
		return result
	default:
		panic(fmt.Sprintf("NIC %d: failed to add address %s: %s", id, protocolAddr.AddressWithPrefix, status))
	}
}

func (ns *Netstack) delInterfaceAddr(id uint64, ifAddr net.Subnet) stack.StackDelInterfaceAddressResult {
	protocolAddr := toProtocolAddr(ifAddr)
	if protocolAddr.AddressWithPrefix.PrefixLen > 8*len(protocolAddr.AddressWithPrefix.Address) {
		return stack.StackDelInterfaceAddressResultWithErr(stack.ErrorInvalidArgs)
	}

	switch status := ns.removeInterfaceAddress(tcpip.NICID(id), protocolAddr, true /* removeRoute */); status {
	case zx.ErrOk:
		return stack.StackDelInterfaceAddressResultWithResponse(stack.StackDelInterfaceAddressResponse{})
	case zx.ErrNotFound:
		return stack.StackDelInterfaceAddressResultWithErr(stack.ErrorNotFound)
	default:
		_ = syslog.Errorf("(*Netstack).delInterfaceAddr(%s) failed (NIC %d): %s", protocolAddr.AddressWithPrefix, id, status)
		return stack.StackDelInterfaceAddressResultWithErr(stack.ErrorInternal)
	}
}

func (ns *Netstack) getForwardingTable() []stack.ForwardingEntry {
	ert := ns.GetExtendedRouteTable()
	entries := make([]stack.ForwardingEntry, 0, len(ert))
	for _, er := range ert {
		entries = append(entries, fidlconv.TcpipRouteToForwardingEntry(er.Route))
	}
	return entries
}

// validateSubnet returns true if the prefix length is valid and no
// address bits are set beyond the prefix length.
func validateSubnet(subnet net.Subnet) bool {
	var ipBytes []uint8
	switch typ := subnet.Addr.Which(); typ {
	case net.IpAddressIpv4:
		ipBytes = subnet.Addr.Ipv4.Addr[:]
	case net.IpAddressIpv6:
		ipBytes = subnet.Addr.Ipv6.Addr[:]
	default:
		panic(fmt.Sprintf("unknown IpAddress type %d", typ))
	}
	if int(subnet.PrefixLen) > len(ipBytes)*8 {
		return false
	}
	prefixBytes := subnet.PrefixLen / 8
	ipBytes = ipBytes[prefixBytes:]
	if prefixBits := subnet.PrefixLen - (prefixBytes * 8); prefixBits > 0 {
		// prefixBits is only greater than zero when ipBytes is non-empty.
		mask := uint8((1 << (8 - prefixBits)) - 1)
		ipBytes[0] &= mask
	}
	for _, byte := range ipBytes {
		if byte != 0 {
			return false
		}
	}
	return true
}

func (ns *Netstack) addForwardingEntry(entry stack.ForwardingEntry) stack.StackAddForwardingEntryResult {
	var result stack.StackAddForwardingEntryResult

	if !validateSubnet(entry.Subnet) {
		result.SetErr(stack.ErrorInvalidArgs)
		return result
	}

	route := fidlconv.ForwardingEntryToTcpipRoute(entry)
	if err := ns.AddRoute(route, metricNotSet, false /* not dynamic */); err != nil {
		if errors.Is(err, routes.ErrNoSuchNIC) {
			result.SetErr(stack.ErrorInvalidArgs)
		} else {
			_ = syslog.Errorf("adding route %s to route table failed: %s", route, err)
			result.SetErr(stack.ErrorInternal)
		}
		return result
	}
	result.SetResponse(stack.StackAddForwardingEntryResponse{})
	return result
}

func (ns *Netstack) delForwardingEntry(subnet net.Subnet) stack.StackDelForwardingEntryResult {
	var result stack.StackDelForwardingEntryResult

	if !validateSubnet(subnet) {
		result.SetErr(stack.ErrorInvalidArgs)
		return result
	}

	destination := fidlconv.ToTCPIPSubnet(subnet)
	if err := ns.DelRoute(tcpip.Route{Destination: destination}); err != nil {
		if errors.Is(err, routes.ErrNoSuchRoute) {
			result.SetErr(stack.ErrorNotFound)
		} else {
			_ = syslog.Errorf("deleting destination %s from route table failed: %s", destination, err)
			result.SetErr(stack.ErrorInternal)
		}
		return result
	}
	result.SetResponse(stack.StackDelForwardingEntryResponse{})
	return result
}

func (ni *stackImpl) AddEthernetInterface(_ fidl.Context, topologicalPath string, device fidlethernet.DeviceWithCtxInterface) (stack.StackAddEthernetInterfaceResult, error) {
	var result stack.StackAddEthernetInterfaceResult
	if ifs, err := ni.ns.addEth(topologicalPath, netstack.InterfaceConfig{}, &device); err != nil {
		var tcpipErr *TcpIpError
		if errors.As(err, &tcpipErr) {
			result.SetErr(tcpipErr.ToStackError())
		} else {
			result.SetErr(stack.ErrorInternal)
		}
	} else {
		result.SetResponse(stack.StackAddEthernetInterfaceResponse{
			Id: uint64(ifs.nicid),
		})
	}
	return result, nil
}

func (ni *stackImpl) DelEthernetInterface(_ fidl.Context, id uint64) (stack.StackDelEthernetInterfaceResult, error) {
	return ni.ns.delInterface(id), nil
}

func (ni *stackImpl) ListInterfaces(fidl.Context) ([]stack.InterfaceInfo, error) {
	return ni.ns.getNetInterfaces(), nil
}

func (ni *stackImpl) GetInterfaceInfo(_ fidl.Context, id uint64) (stack.StackGetInterfaceInfoResult, error) {
	return ni.ns.getInterface(id), nil
}

func (ni *stackImpl) EnableInterface(_ fidl.Context, id uint64) (stack.StackEnableInterfaceResult, error) {
	return ni.ns.enableInterface(id), nil
}

func (ni *stackImpl) DisableInterface(_ fidl.Context, id uint64) (stack.StackDisableInterfaceResult, error) {
	return ni.ns.disableInterface(id), nil
}

func (ni *stackImpl) AddInterfaceAddress(_ fidl.Context, id uint64, addr net.Subnet) (stack.StackAddInterfaceAddressResult, error) {
	return ni.ns.addInterfaceAddr(id, addr), nil
}

func (ni *stackImpl) DelInterfaceAddress(_ fidl.Context, id uint64, addr net.Subnet) (stack.StackDelInterfaceAddressResult, error) {
	return ni.ns.delInterfaceAddr(id, addr), nil
}

func (ni *stackImpl) GetForwardingTable(fidl.Context) ([]stack.ForwardingEntry, error) {
	return ni.ns.getForwardingTable(), nil
}

func (ni *stackImpl) AddForwardingEntry(_ fidl.Context, entry stack.ForwardingEntry) (stack.StackAddForwardingEntryResult, error) {
	return ni.ns.addForwardingEntry(entry), nil
}

func (ni *stackImpl) DelForwardingEntry(_ fidl.Context, subnet net.Subnet) (stack.StackDelForwardingEntryResult, error) {
	return ni.ns.delForwardingEntry(subnet), nil
}

func (ni *stackImpl) EnableIpForwarding(fidl.Context) error {
	for _, protocol := range []tcpip.NetworkProtocolNumber{
		ipv4.ProtocolNumber,
		ipv6.ProtocolNumber,
	} {
		ni.ns.stack.SetForwardingDefaultAndAllNICs(protocol, true)
	}
	return nil
}

func (ni *stackImpl) DisableIpForwarding(fidl.Context) error {
	for _, protocol := range []tcpip.NetworkProtocolNumber{
		ipv4.ProtocolNumber,
		ipv6.ProtocolNumber,
	} {
		ni.ns.stack.SetForwardingDefaultAndAllNICs(protocol, false)
	}
	return nil
}

func (ni *stackImpl) GetInterfaceIpForwarding(_ fidl.Context, id uint64, ip net.IpVersion) (stack.StackGetInterfaceIpForwardingResult, error) {
	netProto, ok := fidlconv.ToTCPNetProto(ip)
	if !ok {
		return stack.StackGetInterfaceIpForwardingResultWithErr(stack.ErrorInvalidArgs), nil
	}

	switch enabled, err := ni.ns.stack.NICForwarding(tcpip.NICID(id), netProto); err.(type) {
	case nil:
		return stack.StackGetInterfaceIpForwardingResultWithResponse(stack.StackGetInterfaceIpForwardingResponse{Enabled: enabled}), nil
	case *tcpip.ErrUnknownNICID:
		return stack.StackGetInterfaceIpForwardingResultWithErr(stack.ErrorNotFound), nil
	default:
		panic(fmt.Sprintf("ni.ns.stack.SetNICForwarding(tcpip.NICID(%d), %d, %t): %s", id, netProto, enabled, err))
	}
}

func (ni *stackImpl) SetInterfaceIpForwarding(_ fidl.Context, id uint64, ip net.IpVersion, enabled bool) (stack.StackSetInterfaceIpForwardingResult, error) {
	netProto, ok := fidlconv.ToTCPNetProto(ip)
	if !ok {
		return stack.StackSetInterfaceIpForwardingResultWithErr(stack.ErrorInvalidArgs), nil
	}

	switch err := ni.ns.stack.SetNICForwarding(tcpip.NICID(id), netProto, enabled); err.(type) {
	case nil:
		return stack.StackSetInterfaceIpForwardingResultWithResponse(stack.StackSetInterfaceIpForwardingResponse{}), nil
	case *tcpip.ErrUnknownNICID:
		return stack.StackSetInterfaceIpForwardingResultWithErr(stack.ErrorNotFound), nil
	default:
		panic(fmt.Sprintf("ni.ns.stack.SetNICForwarding(tcpip.NICID(%d), %d, %t): %s", id, netProto, enabled, err))
	}
}

func (ni *stackImpl) GetDnsServerWatcher(ctx_ fidl.Context, watcher name.DnsServerWatcherWithCtxInterfaceRequest) error {
	return ni.dnsWatchers.Bind(watcher)
}

var _ stack.LogWithCtx = (*logImpl)(nil)

type logImpl struct {
	logPackets *uint32
}

func (li *logImpl) SetLogPackets(_ fidl.Context, enabled bool) error {
	var val uint32
	if enabled {
		val = 1
	}
	atomic.StoreUint32(li.logPackets, val)
	syslog.VLogTf(syslog.DebugVerbosity, "fuchsia_net_stack", "SetLogPackets: %t", enabled)
	return nil
}