1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
|
// Copyright 2020 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 ethernet provides an implementation of an ethernet link endpoint that
// wraps an inner link endpoint.
package ethernet
import (
"gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/tcpip/header"
"gvisor.dev/gvisor/pkg/tcpip/link/nested"
"gvisor.dev/gvisor/pkg/tcpip/stack"
)
var _ stack.NetworkDispatcher = (*Endpoint)(nil)
var _ stack.LinkEndpoint = (*Endpoint)(nil)
// New returns an ethernet link endpoint that wraps an inner link endpoint.
func New(ep stack.LinkEndpoint) *Endpoint {
var e Endpoint
e.Endpoint.Init(ep, &e)
return &e
}
// Endpoint is an ethernet endpoint.
//
// It adds an ethernet header to packets before sending them out through its
// inner link endpoint and consumes an ethernet header before sending the
// packet to the stack.
//
// +stateify savable
type Endpoint struct {
nested.Endpoint
}
// LinkAddress implements stack.LinkEndpoint.
func (e *Endpoint) LinkAddress() tcpip.LinkAddress {
if l := e.Endpoint.LinkAddress(); len(l) != 0 {
return l
}
return header.UnspecifiedEthernetAddress
}
// MTU implements stack.LinkEndpoint.
func (e *Endpoint) MTU() uint32 {
if mtu := e.Endpoint.MTU(); mtu > header.EthernetMinimumSize {
return mtu - header.EthernetMinimumSize
}
return 0
}
// DeliverNetworkPacket implements stack.NetworkDispatcher.
func (e *Endpoint) DeliverNetworkPacket(_ tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) {
if !e.ParseHeader(pkt) {
return
}
eth := header.Ethernet(pkt.LinkHeader().Slice())
dst := eth.DestinationAddress()
if dst == header.EthernetBroadcastAddress {
pkt.PktType = tcpip.PacketBroadcast
} else if header.IsMulticastEthernetAddress(dst) {
pkt.PktType = tcpip.PacketMulticast
} else if dst == e.LinkAddress() {
pkt.PktType = tcpip.PacketHost
} else {
pkt.PktType = tcpip.PacketOtherHost
}
// Note, there is no need to check the destination link address here since
// the ethernet hardware filters frames based on their destination addresses.
e.Endpoint.DeliverNetworkPacket(eth.Type() /* protocol */, pkt)
}
// Capabilities implements stack.LinkEndpoint.
func (e *Endpoint) Capabilities() stack.LinkEndpointCapabilities {
c := e.Endpoint.Capabilities()
if c&stack.CapabilityLoopback == 0 {
c |= stack.CapabilityResolutionRequired
}
return c
}
// MaxHeaderLength implements stack.LinkEndpoint.
func (e *Endpoint) MaxHeaderLength() uint16 {
return header.EthernetMinimumSize + e.Endpoint.MaxHeaderLength()
}
// ARPHardwareType implements stack.LinkEndpoint.
func (e *Endpoint) ARPHardwareType() header.ARPHardwareType {
if a := e.Endpoint.ARPHardwareType(); a != header.ARPHardwareNone {
return a
}
return header.ARPHardwareEther
}
// AddHeader implements stack.LinkEndpoint.
func (*Endpoint) AddHeader(pkt *stack.PacketBuffer) {
eth := header.Ethernet(pkt.LinkHeader().Push(header.EthernetMinimumSize))
fields := header.EthernetFields{
SrcAddr: pkt.EgressRoute.LocalLinkAddress,
DstAddr: pkt.EgressRoute.RemoteLinkAddress,
Type: pkt.NetworkProtocolNumber,
}
eth.Encode(&fields)
}
// ParseHeader implements stack.LinkEndpoint.
func (*Endpoint) ParseHeader(pkt *stack.PacketBuffer) bool {
_, ok := pkt.LinkHeader().Consume(header.EthernetMinimumSize)
return ok
}
|
