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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 contains the implementation of the UDP transport protocol. To use
// it in the networking stack, this package must be added to the project, and
// activated on the stack by passing udp.ProtocolName (or "udp") as one of the
// transport protocols when calling stack.New(). Then endpoints can be created
// by passing udp.ProtocolNumber as the transport protocol number when calling
// Stack.NewEndpoint().
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"
"gvisor.googlesource.com/gvisor/pkg/waiter"
)
const (
// ProtocolName is the string representation of the udp protocol name.
ProtocolName = "udp"
// ProtocolNumber is the udp protocol number.
ProtocolNumber = header.UDPProtocolNumber
)
type protocol struct{}
// Number returns the udp protocol number.
func (*protocol) Number() tcpip.TransportProtocolNumber {
return ProtocolNumber
}
// NewEndpoint creates a new udp endpoint.
func (*protocol) NewEndpoint(stack *stack.Stack, netProto tcpip.NetworkProtocolNumber, waiterQueue *waiter.Queue) (tcpip.Endpoint, *tcpip.Error) {
return newEndpoint(stack, netProto, waiterQueue), nil
}
// NewRawEndpoint creates a new raw UDP endpoint. Raw UDP sockets are currently
// unsupported. It implements stack.TransportProtocol.NewRawEndpoint.
func (p *protocol) NewRawEndpoint(stack *stack.Stack, netProto tcpip.NetworkProtocolNumber, waiterQueue *waiter.Queue) (tcpip.Endpoint, *tcpip.Error) {
return nil, tcpip.ErrUnknownProtocol
}
// MinimumPacketSize returns the minimum valid udp packet size.
func (*protocol) MinimumPacketSize() int {
return header.UDPMinimumSize
}
// ParsePorts returns the source and destination ports stored in the given udp
// packet.
func (*protocol) ParsePorts(v buffer.View) (src, dst uint16, err *tcpip.Error) {
h := header.UDP(v)
return h.SourcePort(), h.DestinationPort(), nil
}
// HandleUnknownDestinationPacket handles packets targeted at this protocol but
// that don't match any existing endpoint.
func (p *protocol) HandleUnknownDestinationPacket(*stack.Route, stack.TransportEndpointID, buffer.VectorisedView) bool {
return true
}
// SetOption implements TransportProtocol.SetOption.
func (p *protocol) SetOption(option interface{}) *tcpip.Error {
return tcpip.ErrUnknownProtocolOption
}
// Option implements TransportProtocol.Option.
func (p *protocol) Option(option interface{}) *tcpip.Error {
return tcpip.ErrUnknownProtocolOption
}
func init() {
stack.RegisterTransportProtocolFactory(ProtocolName, func() stack.TransportProtocol {
return &protocol{}
})
}
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