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
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
|
package netlink
import (
"context"
"syscall"
"unsafe"
)
// RouteConn represents a NETLINK_ROUTE socket.
type RouteConn struct{ conn *Conn }
// Close closes the underlying socket.
func (c *RouteConn) Close() error { return c.conn.Close() }
// DialRoute returns the address of a newly connected [RouteConn].
func DialRoute(rcvbuf int64) (*RouteConn, error) {
c, err := Dial(syscall.NETLINK_ROUTE, 0, rcvbuf)
if err != nil {
return nil, err
}
return &RouteConn{c}, nil
}
// rtnlConsume consumes a message from rtnetlink.
func (c *RouteConn) rtnlConsume(resp []syscall.NetlinkMessage) error {
for i := range resp {
if err := c.conn.checkReply(&resp[i].Header); err != nil {
return err
}
switch resp[i].Header.Type {
case syscall.NLMSG_DONE:
return Complete{}
case syscall.NLMSG_ERROR:
if e := As[syscall.NlMsgerr](resp[i].Data); e != nil {
if e.Error == 0 {
return Complete{}
}
return syscall.Errno(-e.Error)
}
return syscall.EBADE
}
}
return nil
}
// InAddr is equivalent to struct in_addr.
type InAddr [4]byte
// RtAttrMsg holds syscall.RtAttr alongside its payload.
type RtAttrMsg[D any] struct {
syscall.RtAttr
Data D
}
// populate populates the Len field of the embedded syscall.RtAttr.
func (attr *RtAttrMsg[M]) populate() {
attr.Len = syscall.SizeofRtAttr + uint16(unsafe.Sizeof(attr.Data))
}
// writeIfAddrmsg writes an ifaddrmsg structure to conn.
func (c *RouteConn) writeIfAddrmsg(
typ, flags uint16,
msg *syscall.IfAddrmsg,
attrs ...RtAttrMsg[InAddr],
) bool {
c.conn.typ, c.conn.flags = typ, syscall.NLM_F_REQUEST|syscall.NLM_F_ACK|flags
if !add(c.conn, msg) {
return false
}
for _, attr := range attrs {
attr.populate()
if !add(c.conn, &attr) {
return false
}
}
return true
}
// SendIfAddrmsg sends an ifaddrmsg structure to rtnetlink.
func (c *RouteConn) SendIfAddrmsg(
ctx context.Context,
typ, flags uint16,
msg *syscall.IfAddrmsg,
attrs ...RtAttrMsg[InAddr],
) error {
if !c.writeIfAddrmsg(typ, flags, msg, attrs...) {
return syscall.ENOMEM
}
return c.conn.Roundtrip(ctx, c.rtnlConsume)
}
// writeNewaddrLo writes a RTM_NEWADDR message for the loopback address.
func (c *RouteConn) writeNewaddrLo(lo uint32) bool {
return c.writeIfAddrmsg(
syscall.RTM_NEWADDR,
syscall.NLM_F_CREATE|syscall.NLM_F_EXCL,
&syscall.IfAddrmsg{
Family: syscall.AF_INET,
Prefixlen: 8,
Flags: syscall.IFA_F_PERMANENT,
Scope: syscall.RT_SCOPE_HOST,
Index: lo,
},
RtAttrMsg[InAddr]{syscall.RtAttr{
Type: syscall.IFA_LOCAL,
}, InAddr{127, 0, 0, 1}},
RtAttrMsg[InAddr]{syscall.RtAttr{
Type: syscall.IFA_ADDRESS,
}, InAddr{127, 0, 0, 1}},
)
}
// SendNewaddrLo sends a RTM_NEWADDR message for the loopback address to the kernel.
func (c *RouteConn) SendNewaddrLo(ctx context.Context, lo uint32) error {
if !c.writeNewaddrLo(lo) {
return syscall.ENOMEM
}
return c.conn.Roundtrip(ctx, c.rtnlConsume)
}
// writeIfInfomsg writes an ifinfomsg structure to conn.
func (c *RouteConn) writeIfInfomsg(
typ, flags uint16,
msg *syscall.IfInfomsg,
) bool {
c.conn.typ, c.conn.flags = typ, syscall.NLM_F_REQUEST|syscall.NLM_F_ACK|flags
return add(c.conn, msg)
}
// SendIfInfomsg sends an ifinfomsg structure to rtnetlink.
func (c *RouteConn) SendIfInfomsg(
ctx context.Context,
typ, flags uint16,
msg *syscall.IfInfomsg,
) error {
if !c.writeIfInfomsg(typ, flags, msg) {
return syscall.ENOMEM
}
return c.conn.Roundtrip(ctx, c.rtnlConsume)
}
|
