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
|
package ipmanager
import (
"net"
"os/exec"
"syscall"
)
// htons converts uint16 to network byte order
func htons(i uint16) uint16 {
return (i<<8)&0xff00 | i>>8
}
func sendPacketLinux(iface net.Interface, packetData []byte) error {
fd, err := syscall.Socket(syscall.AF_PACKET, syscall.SOCK_RAW, int(htons(syscall.ETH_P_ALL)))
if err != nil {
return err
}
defer syscall.Close(fd)
var sll syscall.SockaddrLinklayer
sll.Protocol = htons(syscall.ETH_P_ARP)
sll.Ifindex = iface.Index
sll.Hatype = syscall.ARPHRD_ETHER
sll.Pkttype = syscall.PACKET_BROADCAST
if err = syscall.Bind(fd, &sll); err != nil {
return err
}
return syscall.Sendto(fd, packetData, 0, &sll)
}
// configureAddress assigns virtual IP address
func (c *BasicConfigurer) configureAddress() bool {
log.Infof("Configuring address %s on %s", c.getCIDR(), c.Iface.Name)
result := c.runAddressConfiguration("add")
if result {
if buff, err := c.createGratuitousARP(); err != nil {
log.Warn("Failed to compose gratuitous ARP request: ", err)
} else {
if err := sendPacketLinux(c.Iface, buff); err != nil {
log.Warn("Failed to send gratuitous ARP request: ", err)
}
}
}
return result
}
// deconfigureAddress drops virtual IP address
func (c *BasicConfigurer) deconfigureAddress() bool {
log.Infof("Removing address %s on %s", c.getCIDR(), c.Iface.Name)
return c.runAddressConfiguration("delete")
}
func (c *BasicConfigurer) runAddressConfiguration(action string) bool {
cmd := exec.Command("ip", "addr", action,
c.getCIDR(),
"dev", c.Iface.Name)
output, err := cmd.CombinedOutput()
switch err.(type) {
case *exec.ExitError:
log.Infof("Got error %s", output)
return false
}
if err != nil {
log.Infof("Error running ip address %s %s on %s: %s",
action, c.VIP, c.Iface.Name, err)
return false
}
return true
}
|
