1 package netlink
2
3 import (
4 "fmt"
5
6 "github.com/vishvananda/netlink/nl"
7 "github.com/vishvananda/netns"
8 "golang.org/x/sys/unix"
9 )
10
11 type XfrmMsg interface {
12 Type() nl.XfrmMsgType
13 }
14
15 type XfrmMsgExpire struct {
16 XfrmState *XfrmState
17 Hard bool
18 }
19
20 func (ue *XfrmMsgExpire) Type() nl.XfrmMsgType {
21 return nl.XFRM_MSG_EXPIRE
22 }
23
24 func parseXfrmMsgExpire(b []byte) *XfrmMsgExpire {
25 var e XfrmMsgExpire
26
27 msg := nl.DeserializeXfrmUserExpire(b)
28 e.XfrmState = xfrmStateFromXfrmUsersaInfo(&msg.XfrmUsersaInfo)
29 e.Hard = msg.Hard == 1
30
31 return &e
32 }
33
34 func XfrmMonitor(ch chan<- XfrmMsg, done <-chan struct{}, errorChan chan<- error,
35 types ...nl.XfrmMsgType) error {
36
37 groups, err := xfrmMcastGroups(types)
38 if err != nil {
39 return nil
40 }
41 s, err := nl.SubscribeAt(netns.None(), netns.None(), unix.NETLINK_XFRM, groups...)
42 if err != nil {
43 return err
44 }
45
46 if done != nil {
47 go func() {
48 <-done
49 s.Close()
50 }()
51
52 }
53
54 go func() {
55 defer close(ch)
56 for {
57 msgs, from, err := s.Receive()
58 if err != nil {
59 errorChan <- err
60 return
61 }
62 if from.Pid != nl.PidKernel {
63 errorChan <- fmt.Errorf("Wrong sender portid %d, expected %d", from.Pid, nl.PidKernel)
64 return
65 }
66 for _, m := range msgs {
67 switch m.Header.Type {
68 case nl.XFRM_MSG_EXPIRE:
69 ch <- parseXfrmMsgExpire(m.Data)
70 default:
71 errorChan <- fmt.Errorf("unsupported msg type: %x", m.Header.Type)
72 }
73 }
74 }
75 }()
76
77 return nil
78 }
79
80 func xfrmMcastGroups(types []nl.XfrmMsgType) ([]uint, error) {
81 groups := make([]uint, 0)
82
83 if len(types) == 0 {
84 return nil, fmt.Errorf("no xfrm msg type specified")
85 }
86
87 for _, t := range types {
88 var group uint
89
90 switch t {
91 case nl.XFRM_MSG_EXPIRE:
92 group = nl.XFRMNLGRP_EXPIRE
93 default:
94 return nil, fmt.Errorf("unsupported group: %x", t)
95 }
96
97 groups = append(groups, group)
98 }
99
100 return groups, nil
101 }
102
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