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// Copyright 2018 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package udp
import (
"gvisor.googlesource.com/gvisor/pkg/tcpip"
"gvisor.googlesource.com/gvisor/pkg/tcpip/buffer"
"gvisor.googlesource.com/gvisor/pkg/tcpip/header"
"gvisor.googlesource.com/gvisor/pkg/tcpip/stack"
)
// saveData saves udpPacket.data field.
func (u *udpPacket) saveData() buffer.VectorisedView {
// We cannot save u.data directly as u.data.views may alias to u.views,
// which is not allowed by state framework (in-struct pointer).
return u.data.Clone(nil)
}
// loadData loads udpPacket.data field.
func (u *udpPacket) loadData(data buffer.VectorisedView) {
// NOTE: We cannot do the u.data = data.Clone(u.views[:]) optimization
// here because data.views is not guaranteed to be loaded by now. Plus,
// data.views will be allocated anyway so there really is little point
// of utilizing u.views for data.views.
u.data = data
}
// beforeSave is invoked by stateify.
func (e *endpoint) beforeSave() {
// Stop incoming packets from being handled (and mutate endpoint state).
// The lock will be released after savercvBufSizeMax(), which would have
// saved e.rcvBufSizeMax and set it to 0 to continue blocking incoming
// packets.
e.rcvMu.Lock()
}
// saveRcvBufSizeMax is invoked by stateify.
func (e *endpoint) saveRcvBufSizeMax() int {
max := e.rcvBufSizeMax
// Make sure no new packets will be handled regardless of the lock.
e.rcvBufSizeMax = 0
// Release the lock acquired in beforeSave() so regular endpoint closing
// logic can proceed after save.
e.rcvMu.Unlock()
return max
}
// loadRcvBufSizeMax is invoked by stateify.
func (e *endpoint) loadRcvBufSizeMax(max int) {
e.rcvBufSizeMax = max
}
// afterLoad is invoked by stateify.
func (e *endpoint) afterLoad() {
e.stack = stack.StackFromEnv
for _, m := range e.multicastMemberships {
if err := e.stack.JoinGroup(e.netProto, m.nicID, m.multicastAddr); err != nil {
panic(err)
}
}
if e.state != stateBound && e.state != stateConnected {
return
}
netProto := e.effectiveNetProtos[0]
// Connect() and bindLocked() both assert
//
// netProto == header.IPv6ProtocolNumber
//
// before creating a multi-entry effectiveNetProtos.
if len(e.effectiveNetProtos) > 1 {
netProto = header.IPv6ProtocolNumber
}
var err *tcpip.Error
if e.state == stateConnected {
e.route, err = e.stack.FindRoute(e.regNICID, e.id.LocalAddress, e.id.RemoteAddress, netProto, e.multicastLoop)
if err != nil {
panic(*err)
}
e.id.LocalAddress = e.route.LocalAddress
} else if len(e.id.LocalAddress) != 0 { // stateBound
if e.stack.CheckLocalAddress(e.regNICID, netProto, e.id.LocalAddress) == 0 {
panic(tcpip.ErrBadLocalAddress)
}
}
// Our saved state had a port, but we don't actually have a
// reservation. We need to remove the port from our state, but still
// pass it to the reservation machinery.
id := e.id
e.id.LocalPort = 0
e.id, err = e.registerWithStack(e.regNICID, e.effectiveNetProtos, id)
if err != nil {
panic(*err)
}
}
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