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
|
// 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 netdevs contains utilities for working with network devices.
package netdevs
import (
"fmt"
"net"
"regexp"
"strings"
"gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/tcpip/header"
)
// A DeviceInfo represents a network device.
type DeviceInfo struct {
MAC net.HardwareAddr
IPv4Addr net.IP
IPv4Net *net.IPNet
IPv6Addr net.IP
IPv6Net *net.IPNet
}
var (
deviceLine = regexp.MustCompile(`^\s*\d+: (\w+)`)
linkLine = regexp.MustCompile(`^\s*link/\w+ ([0-9a-fA-F:]+)`)
inetLine = regexp.MustCompile(`^\s*inet ([0-9./]+)`)
inet6Line = regexp.MustCompile(`^\s*inet6 ([0-9a-fA-Z:/]+)`)
)
// ParseDevices parses the output from `ip addr show` into a map from device
// name to information about the device.
func ParseDevices(cmdOutput string) (map[string]DeviceInfo, error) {
var currentDevice string
var currentInfo DeviceInfo
deviceInfos := make(map[string]DeviceInfo)
for _, line := range strings.Split(cmdOutput, "\n") {
if m := deviceLine.FindStringSubmatch(line); m != nil {
if currentDevice != "" {
deviceInfos[currentDevice] = currentInfo
}
currentInfo = DeviceInfo{}
currentDevice = m[1]
} else if m := linkLine.FindStringSubmatch(line); m != nil {
mac, err := net.ParseMAC(m[1])
if err != nil {
return nil, err
}
currentInfo.MAC = mac
} else if m := inetLine.FindStringSubmatch(line); m != nil {
ipv4Addr, ipv4Net, err := net.ParseCIDR(m[1])
if err != nil {
return nil, err
}
currentInfo.IPv4Addr = ipv4Addr
currentInfo.IPv4Net = ipv4Net
} else if m := inet6Line.FindStringSubmatch(line); m != nil {
ipv6Addr, ipv6Net, err := net.ParseCIDR(m[1])
if err != nil {
return nil, err
}
currentInfo.IPv6Addr = ipv6Addr
currentInfo.IPv6Net = ipv6Net
}
}
if currentDevice != "" {
deviceInfos[currentDevice] = currentInfo
}
return deviceInfos, nil
}
// MACToIP converts the MAC address to an IPv6 link local address as described
// in RFC 4291 page 20: https://tools.ietf.org/html/rfc4291#page-20
func MACToIP(mac net.HardwareAddr) net.IP {
addr := make([]byte, header.IPv6AddressSize)
addr[0] = 0xfe
addr[1] = 0x80
header.EthernetAdddressToModifiedEUI64IntoBuf(tcpip.LinkAddress(mac), addr[8:])
return net.IP(addr)
}
// FindDeviceByIP finds a DeviceInfo and device name from an IP address in the
// output of ParseDevices.
func FindDeviceByIP(ip net.IP, devices map[string]DeviceInfo) (string, DeviceInfo, error) {
for dev, info := range devices {
if info.IPv4Addr.Equal(ip) {
return dev, info, nil
}
}
return "", DeviceInfo{}, fmt.Errorf("can't find %s on any interface", ip)
}
|
