github.com/SagerNet/gvisor@v0.0.0-20210707092255-7731c139d75c/pkg/tcpip/transport/raw/endpoint_state.go (about)

     1  // Copyright 2018 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package raw
    16  
    17  import (
    18  	"time"
    19  
    20  	"github.com/SagerNet/gvisor/pkg/tcpip"
    21  	"github.com/SagerNet/gvisor/pkg/tcpip/buffer"
    22  	"github.com/SagerNet/gvisor/pkg/tcpip/stack"
    23  )
    24  
    25  // saveReceivedAt is invoked by stateify.
    26  func (p *rawPacket) saveReceivedAt() int64 {
    27  	return p.receivedAt.UnixNano()
    28  }
    29  
    30  // loadReceivedAt is invoked by stateify.
    31  func (p *rawPacket) loadReceivedAt(nsec int64) {
    32  	p.receivedAt = time.Unix(0, nsec)
    33  }
    34  
    35  // saveData saves rawPacket.data field.
    36  func (p *rawPacket) saveData() buffer.VectorisedView {
    37  	// We cannot save p.data directly as p.data.views may alias to p.views,
    38  	// which is not allowed by state framework (in-struct pointer).
    39  	return p.data.Clone(nil)
    40  }
    41  
    42  // loadData loads rawPacket.data field.
    43  func (p *rawPacket) loadData(data buffer.VectorisedView) {
    44  	// NOTE: We cannot do the p.data = data.Clone(p.views[:]) optimization
    45  	// here because data.views is not guaranteed to be loaded by now. Plus,
    46  	// data.views will be allocated anyway so there really is little point
    47  	// of utilizing p.views for data.views.
    48  	p.data = data
    49  }
    50  
    51  // afterLoad is invoked by stateify.
    52  func (e *endpoint) afterLoad() {
    53  	stack.StackFromEnv.RegisterRestoredEndpoint(e)
    54  }
    55  
    56  // beforeSave is invoked by stateify.
    57  func (e *endpoint) beforeSave() {
    58  	e.freeze()
    59  }
    60  
    61  // Resume implements tcpip.ResumableEndpoint.Resume.
    62  func (e *endpoint) Resume(s *stack.Stack) {
    63  	e.thaw()
    64  	e.stack = s
    65  	e.ops.InitHandler(e, e.stack, tcpip.GetStackSendBufferLimits, tcpip.GetStackReceiveBufferLimits)
    66  
    67  	// If the endpoint is connected, re-connect.
    68  	if e.connected {
    69  		var err tcpip.Error
    70  		// TODO(github.com/SagerNet/issue/4906): Properly restore the route with the right
    71  		// remote address. We used to pass e.remote.RemoteAddress which was
    72  		// effectively the empty address but since moving e.route to hold a pointer
    73  		// to a route instead of the route by value, we pass the empty address
    74  		// directly. Obviously this was always wrong since we should provide the
    75  		// remote address we were connected to, to properly restore the route.
    76  		e.route, err = e.stack.FindRoute(e.RegisterNICID, e.BindAddr, "", e.NetProto, false)
    77  		if err != nil {
    78  			panic(err)
    79  		}
    80  	}
    81  
    82  	// If the endpoint is bound, re-bind.
    83  	if e.bound {
    84  		if e.stack.CheckLocalAddress(e.RegisterNICID, e.NetProto, e.BindAddr) == 0 {
    85  			panic(&tcpip.ErrBadLocalAddress{})
    86  		}
    87  	}
    88  
    89  	if e.associated {
    90  		if err := e.stack.RegisterRawTransportEndpoint(e.NetProto, e.TransProto, e); err != nil {
    91  			panic(err)
    92  		}
    93  	}
    94  }