|
| 1 | +//go:build with_gvisor |
| 2 | + |
| 3 | +package tun |
| 4 | + |
| 5 | +import ( |
| 6 | + "context" |
| 7 | + "errors" |
| 8 | + "net" |
| 9 | + "os" |
| 10 | + "sync" |
| 11 | + "syscall" |
| 12 | + "time" |
| 13 | + |
| 14 | + "github.com/sagernet/gvisor/pkg/tcpip" |
| 15 | + "github.com/sagernet/gvisor/pkg/tcpip/adapters/gonet" |
| 16 | + "github.com/sagernet/gvisor/pkg/tcpip/header" |
| 17 | + "github.com/sagernet/gvisor/pkg/tcpip/stack" |
| 18 | + "github.com/sagernet/gvisor/pkg/tcpip/transport/tcp" |
| 19 | + "github.com/sagernet/gvisor/pkg/waiter" |
| 20 | +) |
| 21 | + |
| 22 | +type gLazyConn struct { |
| 23 | + tcpConn *gonet.TCPConn |
| 24 | + parentCtx context.Context |
| 25 | + stack *stack.Stack |
| 26 | + request *tcp.ForwarderRequest |
| 27 | + localAddr net.Addr |
| 28 | + remoteAddr net.Addr |
| 29 | + handshakeAccess sync.Mutex |
| 30 | + handshakeDone bool |
| 31 | + handshakeErr error |
| 32 | +} |
| 33 | + |
| 34 | +func (c *gLazyConn) HandshakeContext(ctx context.Context) error { |
| 35 | + if c.handshakeDone { |
| 36 | + return nil |
| 37 | + } |
| 38 | + c.handshakeAccess.Lock() |
| 39 | + defer c.handshakeAccess.Unlock() |
| 40 | + if c.handshakeDone { |
| 41 | + return nil |
| 42 | + } |
| 43 | + defer func() { |
| 44 | + c.handshakeDone = true |
| 45 | + }() |
| 46 | + var ( |
| 47 | + wq waiter.Queue |
| 48 | + endpoint tcpip.Endpoint |
| 49 | + ) |
| 50 | + handshakeCtx, cancel := context.WithCancel(ctx) |
| 51 | + go func() { |
| 52 | + select { |
| 53 | + case <-c.parentCtx.Done(): |
| 54 | + wq.Notify(wq.Events()) |
| 55 | + case <-handshakeCtx.Done(): |
| 56 | + } |
| 57 | + }() |
| 58 | + endpoint, err := c.request.CreateEndpoint(&wq) |
| 59 | + cancel() |
| 60 | + if err != nil { |
| 61 | + gErr := gonet.TranslateNetstackError(err) |
| 62 | + c.handshakeErr = gErr |
| 63 | + c.request.Complete(true) |
| 64 | + return gErr |
| 65 | + } |
| 66 | + c.request.Complete(false) |
| 67 | + endpoint.SocketOptions().SetKeepAlive(true) |
| 68 | + keepAliveIdle := tcpip.KeepaliveIdleOption(15 * time.Second) |
| 69 | + endpoint.SetSockOpt(&keepAliveIdle) |
| 70 | + keepAliveInterval := tcpip.KeepaliveIntervalOption(15 * time.Second) |
| 71 | + endpoint.SetSockOpt(&keepAliveInterval) |
| 72 | + tcpConn := gonet.NewTCPConn(&wq, endpoint) |
| 73 | + c.tcpConn = tcpConn |
| 74 | + return nil |
| 75 | +} |
| 76 | + |
| 77 | +func (c *gLazyConn) HandshakeFailure(err error) error { |
| 78 | + if c.handshakeDone { |
| 79 | + return nil |
| 80 | + } |
| 81 | + c.handshakeAccess.Lock() |
| 82 | + defer c.handshakeAccess.Unlock() |
| 83 | + if c.handshakeDone { |
| 84 | + return nil |
| 85 | + } |
| 86 | + wErr := gWriteUnreachable(c.stack, c.request.Packet(), err) |
| 87 | + c.request.Complete(wErr == os.ErrInvalid) |
| 88 | + c.handshakeDone = true |
| 89 | + c.handshakeErr = err |
| 90 | + return nil |
| 91 | +} |
| 92 | + |
| 93 | +func (c *gLazyConn) HandshakeSuccess() error { |
| 94 | + return c.HandshakeContext(context.Background()) |
| 95 | +} |
| 96 | + |
| 97 | +func (c *gLazyConn) Read(b []byte) (n int, err error) { |
| 98 | + if !c.handshakeDone { |
| 99 | + err = c.HandshakeContext(context.Background()) |
| 100 | + if err != nil { |
| 101 | + return |
| 102 | + } |
| 103 | + } else if c.handshakeErr != nil { |
| 104 | + return 0, c.handshakeErr |
| 105 | + } |
| 106 | + return c.tcpConn.Read(b) |
| 107 | +} |
| 108 | + |
| 109 | +func (c *gLazyConn) Write(b []byte) (n int, err error) { |
| 110 | + if !c.handshakeDone { |
| 111 | + err = c.HandshakeContext(context.Background()) |
| 112 | + if err != nil { |
| 113 | + return |
| 114 | + } |
| 115 | + } else if c.handshakeErr != nil { |
| 116 | + return 0, c.handshakeErr |
| 117 | + } |
| 118 | + return c.tcpConn.Write(b) |
| 119 | +} |
| 120 | + |
| 121 | +func (c *gLazyConn) LocalAddr() net.Addr { |
| 122 | + return c.localAddr |
| 123 | +} |
| 124 | + |
| 125 | +func (c *gLazyConn) RemoteAddr() net.Addr { |
| 126 | + return c.remoteAddr |
| 127 | +} |
| 128 | + |
| 129 | +func (c *gLazyConn) SetDeadline(t time.Time) error { |
| 130 | + if !c.handshakeDone { |
| 131 | + err := c.HandshakeContext(context.Background()) |
| 132 | + if err != nil { |
| 133 | + return err |
| 134 | + } |
| 135 | + } else if c.handshakeErr != nil { |
| 136 | + return c.handshakeErr |
| 137 | + } |
| 138 | + return c.tcpConn.SetDeadline(t) |
| 139 | +} |
| 140 | + |
| 141 | +func (c *gLazyConn) SetReadDeadline(t time.Time) error { |
| 142 | + if !c.handshakeDone { |
| 143 | + err := c.HandshakeContext(context.Background()) |
| 144 | + if err != nil { |
| 145 | + return err |
| 146 | + } |
| 147 | + } else if c.handshakeErr != nil { |
| 148 | + return c.handshakeErr |
| 149 | + } |
| 150 | + return c.tcpConn.SetReadDeadline(t) |
| 151 | +} |
| 152 | + |
| 153 | +func (c *gLazyConn) SetWriteDeadline(t time.Time) error { |
| 154 | + if !c.handshakeDone { |
| 155 | + err := c.HandshakeContext(context.Background()) |
| 156 | + if err != nil { |
| 157 | + return err |
| 158 | + } |
| 159 | + } else if c.handshakeErr != nil { |
| 160 | + return c.handshakeErr |
| 161 | + } |
| 162 | + return c.tcpConn.SetWriteDeadline(t) |
| 163 | +} |
| 164 | + |
| 165 | +func (c *gLazyConn) Close() error { |
| 166 | + c.handshakeAccess.Lock() |
| 167 | + defer c.handshakeAccess.Unlock() |
| 168 | + if !c.handshakeDone { |
| 169 | + c.request.Complete(true) |
| 170 | + c.handshakeErr = net.ErrClosed |
| 171 | + return nil |
| 172 | + } else if c.handshakeErr != nil { |
| 173 | + return nil |
| 174 | + } |
| 175 | + return c.tcpConn.Close() |
| 176 | +} |
| 177 | + |
| 178 | +func (c *gLazyConn) CloseRead() error { |
| 179 | + c.handshakeAccess.Lock() |
| 180 | + defer c.handshakeAccess.Unlock() |
| 181 | + if !c.handshakeDone { |
| 182 | + c.request.Complete(true) |
| 183 | + c.handshakeErr = net.ErrClosed |
| 184 | + return nil |
| 185 | + } else if c.handshakeErr != nil { |
| 186 | + return nil |
| 187 | + } |
| 188 | + return c.tcpConn.CloseRead() |
| 189 | +} |
| 190 | + |
| 191 | +func (c *gLazyConn) CloseWrite() error { |
| 192 | + c.handshakeAccess.Lock() |
| 193 | + defer c.handshakeAccess.Unlock() |
| 194 | + if !c.handshakeDone { |
| 195 | + c.request.Complete(true) |
| 196 | + c.handshakeErr = net.ErrClosed |
| 197 | + return nil |
| 198 | + } else if c.handshakeErr != nil { |
| 199 | + return nil |
| 200 | + } |
| 201 | + return c.tcpConn.CloseRead() |
| 202 | +} |
| 203 | + |
| 204 | +func gWriteUnreachable(gStack *stack.Stack, packet *stack.PacketBuffer, err error) error { |
| 205 | + if errors.Is(err, syscall.ENETUNREACH) { |
| 206 | + if packet.NetworkProtocolNumber == header.IPv4ProtocolNumber { |
| 207 | + return gWriteUnreachable4(gStack, packet, stack.RejectIPv4WithICMPPortUnreachable) |
| 208 | + } else { |
| 209 | + return gWriteUnreachable6(gStack, packet, stack.RejectIPv6WithICMPNoRoute) |
| 210 | + } |
| 211 | + } else if errors.Is(err, syscall.EHOSTUNREACH) { |
| 212 | + if packet.NetworkProtocolNumber == header.IPv4ProtocolNumber { |
| 213 | + return gWriteUnreachable4(gStack, packet, stack.RejectIPv4WithICMPHostProhibited) |
| 214 | + } else { |
| 215 | + return gWriteUnreachable6(gStack, packet, stack.RejectIPv6WithICMPNoRoute) |
| 216 | + } |
| 217 | + } else if errors.Is(err, syscall.ECONNREFUSED) { |
| 218 | + if packet.NetworkProtocolNumber == header.IPv4ProtocolNumber { |
| 219 | + return gWriteUnreachable4(gStack, packet, stack.RejectIPv4WithICMPPortUnreachable) |
| 220 | + } else { |
| 221 | + return gWriteUnreachable6(gStack, packet, stack.RejectIPv6WithICMPPortUnreachable) |
| 222 | + } |
| 223 | + } |
| 224 | + return os.ErrInvalid |
| 225 | +} |
| 226 | + |
| 227 | +func gWriteUnreachable4(gStack *stack.Stack, packet *stack.PacketBuffer, icmpCode stack.RejectIPv4WithICMPType) error { |
| 228 | + return gonet.TranslateNetstackError(gStack.NetworkProtocolInstance(header.IPv4ProtocolNumber).(stack.RejectIPv4WithHandler).SendRejectionError(packet, icmpCode, true)) |
| 229 | +} |
| 230 | + |
| 231 | +func gWriteUnreachable6(gStack *stack.Stack, packet *stack.PacketBuffer, icmpCode stack.RejectIPv6WithICMPType) error { |
| 232 | + return gonet.TranslateNetstackError(gStack.NetworkProtocolInstance(header.IPv6ProtocolNumber).(stack.RejectIPv6WithHandler).SendRejectionError(packet, icmpCode, true)) |
| 233 | +} |
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