sing-box/protocol/openvpn/endpoint.go
2026-07-19 13:05:18 +08:00

290 lines
9.4 KiB
Go

package openvpn
import (
"context"
"crypto/subtle"
"net"
"net/netip"
"slices"
"strings"
"github.com/sagernet/sing-box/adapter"
"github.com/sagernet/sing-box/adapter/endpoint"
C "github.com/sagernet/sing-box/constant"
"github.com/sagernet/sing-box/log"
"github.com/sagernet/sing-box/option"
ovpntransport "github.com/sagernet/sing-box/transport/openvpn"
ovpn "github.com/sagernet/sing-openvpn"
"github.com/sagernet/sing-tun"
"github.com/sagernet/sing-tun/gtcpip/header"
"github.com/sagernet/sing/common/auth"
"github.com/sagernet/sing/common/bufio"
E "github.com/sagernet/sing/common/exceptions"
M "github.com/sagernet/sing/common/metadata"
N "github.com/sagernet/sing/common/network"
"go4.org/netipx"
)
func RegisterEndpoint(registry *endpoint.Registry) {
endpoint.Register[option.OpenVPNClientEndpointOptions](registry, C.TypeOpenVPNClient, NewClientEndpoint)
endpoint.Register[option.OpenVPNServerEndpointOptions](registry, C.TypeOpenVPNServer, NewServerEndpoint)
}
type endpointBase struct {
endpoint.Adapter
router adapter.Router
logger log.ContextLogger
}
func (e *endpointBase) SupportsFlow(network string) bool {
return slices.Contains(e.Network(), network)
}
func (e *endpointBase) newConnection(ctx context.Context, endpoint adapter.Endpoint, localAddresses []netip.Prefix, conn net.Conn, source M.Socksaddr, destination M.Socksaddr, onClose N.CloseHandlerFunc) {
var metadata adapter.InboundContext
metadata.Inbound = endpoint.Tag()
metadata.InboundType = endpoint.Type()
metadata.Source = source
if isEndpointLocalAddress(localAddresses, destination.Addr) {
metadata.OriginDestination = destination
destination.Addr = loopbackAddressFor(destination.Addr)
}
metadata.Destination = destination
e.logger.InfoContext(ctx, "inbound connection from ", source)
e.logger.InfoContext(ctx, "inbound connection to ", metadata.Destination)
e.router.RouteConnectionEx(ctx, conn, metadata, onClose)
}
func (e *endpointBase) newPacketConnection(ctx context.Context, endpoint adapter.Endpoint, localAddresses []netip.Prefix, conn N.PacketConn, source M.Socksaddr, destination M.Socksaddr, onClose N.CloseHandlerFunc) {
var metadata adapter.InboundContext
metadata.Inbound = endpoint.Tag()
metadata.InboundType = endpoint.Type()
metadata.Source = source
if isEndpointLocalAddress(localAddresses, destination.Addr) {
metadata.OriginDestination = destination
destination.Addr = loopbackAddressFor(destination.Addr)
conn = bufio.NewNATPacketConn(bufio.NewNetPacketConn(conn), metadata.OriginDestination, destination)
}
metadata.Destination = destination
e.logger.InfoContext(ctx, "inbound packet connection from ", source)
e.logger.InfoContext(ctx, "inbound packet connection to ", metadata.Destination)
e.router.RoutePacketConnectionEx(ctx, conn, metadata, onClose)
}
func (e *endpointBase) newDNSPacket(ctx context.Context, endpoint adapter.Endpoint, payload []byte, source M.Socksaddr, destination M.Socksaddr, writer N.PacketWriter) {
var metadata adapter.InboundContext
metadata.Inbound = endpoint.Tag()
metadata.InboundType = endpoint.Type()
metadata.Network = N.NetworkUDP
metadata.Source = source
metadata.Destination = destination
metadata.Protocol = C.ProtocolDNS
e.logger.InfoContext(ctx, "inbound DNS packet from ", source)
e.router.HijackDNSPacket(ctx, payload, writer, metadata)
}
func isEndpointLocalAddress(localAddresses []netip.Prefix, address netip.Addr) bool {
for _, localPrefix := range localAddresses {
if address == localPrefix.Addr() {
return true
}
}
return false
}
func loopbackAddressFor(address netip.Addr) netip.Addr {
if address.Is4() {
return netip.AddrFrom4([4]uint8{127, 0, 0, 1})
}
return netip.IPv6Loopback()
}
func judgeOpenVPNFlow(router adapter.Router, tag string, endpointType string, localAddresses []netip.Prefix, network uint8, source netip.AddrPort, destination netip.AddrPort, firstPacket []byte) tun.FlowVerdict {
for _, localPrefix := range localAddresses {
if destination.Addr() == localPrefix.Addr() {
return tun.FlowVerdict{Action: tun.ActionAccept}
}
}
return adapter.JudgeFlow(router, tag, endpointType, network, source, destination, firstPacket)
}
func keyDirectionValue(direction string) (int, error) {
switch direction {
case "":
return -1, nil
case "server":
return 0, nil
case "client":
return 1, nil
default:
return 0, E.New("unsupported OpenVPN key direction: ", direction, " (expected \"server\" or \"client\")")
}
}
func openVPNClientRemoteIsDomain(options option.OpenVPNClientEndpointOptions) bool {
if options.Server != "" && options.ServerIsDomain() {
return true
}
for _, remoteOptions := range options.Servers {
if remoteOptions.Build().IsDomain() {
return true
}
}
return false
}
func materialSource(name string, inlineValues []string, path string) (ovpn.Material, error) {
material := ovpn.Material{Path: path}
if len(inlineValues) > 0 {
material.Content = []byte(strings.Join(inlineValues, "\n"))
}
return material, material.Validate(name)
}
func requiredMaterialSource(name string, inlineValues []string, path string) (ovpn.Material, error) {
material, err := materialSource(name, inlineValues, path)
if err != nil {
return ovpn.Material{}, err
}
if !material.IsSet() {
return ovpn.Material{}, E.New("missing `", name, "` or `", name, "_path`")
}
return material, nil
}
func configurationFromClientEvent(event ovpn.TunnelConfigurationEvent, logger log.ContextLogger) ovpntransport.Configuration {
configuration := event.Configuration
var addresses []netip.Prefix
addresses = append(addresses, configuration.LocalIPv4...)
addresses = append(addresses, configuration.LocalIPv6...)
mtu := configuration.TunMTU
if mtu == 0 {
mtu = ovpntransport.DefaultMTU
}
var routes []ovpntransport.Route
inet4DefaultRoute := netip.PrefixFrom(netip.IPv4Unspecified(), 0)
inet6DefaultRoute := netip.PrefixFrom(netip.IPv6Unspecified(), 0)
var hasInet4DefaultRoute bool
var hasInet6DefaultRoute bool
for _, route := range configuration.IPv4Routes {
routes = append(routes, ovpntransport.Route{
Prefix: route.Prefix,
Gateway: route.Gateway,
Metric: route.Metric,
})
if route.Prefix == inet4DefaultRoute {
hasInet4DefaultRoute = true
}
}
for _, route := range configuration.IPv6Routes {
routes = append(routes, ovpntransport.Route{
Prefix: route.Prefix,
Gateway: route.Gateway,
Metric: route.Metric,
})
if route.Prefix == inet6DefaultRoute {
hasInet6DefaultRoute = true
}
}
if configuration.RedirectGateway {
if !hasOpenVPNFlag(configuration.RedirectGatewayFlags, "!ipv4") && !hasInet4DefaultRoute {
routes = append(routes, ovpntransport.Route{
Prefix: inet4DefaultRoute,
Gateway: configuration.VPNGateway,
Metric: configuration.RouteMetric,
})
}
if hasOpenVPNFlag(configuration.RedirectGatewayFlags, "ipv6") && !hasInet6DefaultRoute {
routes = append(routes, ovpntransport.Route{
Prefix: inet6DefaultRoute,
Gateway: configuration.VPNGatewayIPv6,
Metric: configuration.RouteMetric,
})
hasInet6DefaultRoute = true
}
}
if configuration.BlockIPv6 && !hasInet6DefaultRoute {
routes = append(routes, ovpntransport.Route{
Prefix: inet6DefaultRoute,
Gateway: configuration.VPNGatewayIPv6,
Metric: configuration.RouteMetric,
})
}
var ignoredOptions []string
for _, flag := range configuration.RedirectGatewayFlags {
switch strings.ToLower(flag) {
case "!ipv4", "ipv6":
default:
if flag != "" {
ignoredOptions = append(ignoredOptions, "redirect-gateway "+flag)
}
}
}
if configuration.RedirectPrivate {
ignoredOptions = append(ignoredOptions, "redirect-private")
}
if configuration.BlockOutsideDNS {
ignoredOptions = append(ignoredOptions, "block-outside-dns")
}
for _, dhcpOption := range configuration.DHCPOptions {
fields := strings.Fields(dhcpOption)
if len(fields) == 0 || strings.EqualFold(fields[0], "DNS") || strings.EqualFold(fields[0], "DNS6") {
continue
}
ignoredOptions = append(ignoredOptions, "dhcp-option "+strings.TrimSpace(dhcpOption))
}
if len(ignoredOptions) > 0 && logger != nil {
logger.Debug("ignored pushed OpenVPN options: ", strings.Join(ignoredOptions, ", "))
}
return ovpntransport.Configuration{
MTU: mtu,
Address: addresses,
Routes: routes,
DNS: configuration.DNS,
Topology: configuration.Topology,
BlockIPv6: configuration.BlockIPv6,
}
}
func buildIPSet(routes []ovpntransport.Route) (*netipx.IPSet, error) {
var builder netipx.IPSetBuilder
for _, route := range routes {
builder.AddPrefix(route.Prefix)
}
return builder.IPSet()
}
func hasOpenVPNFlag(flags []string, flag string) bool {
for _, value := range flags {
if strings.EqualFold(value, flag) {
return true
}
}
return false
}
func packetSourceAddress(packet []byte, inet4Address netip.Addr, inet6Address netip.Addr) netip.Addr {
if header.IPVersion(packet) == header.IPv6Version {
return inet6Address
}
return inet4Address
}
func authenticatorFromUsers(users []auth.User) ovpn.UserPassAuthenticator {
if len(users) == 0 {
return nil
}
passwordByUsername := make(map[string]string, len(users))
for _, user := range users {
passwordByUsername[user.Username] = user.Password
}
return func(ctx context.Context, username string, password string) error {
expectedPassword, found := passwordByUsername[username]
if !found || subtle.ConstantTimeCompare([]byte(expectedPassword), []byte(password)) != 1 {
return E.New("invalid username or password")
}
return nil
}
}