/
udpconn_bindtodevice.go
47 lines (42 loc) · 1.49 KB
/
udpconn_bindtodevice.go
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
// +build !windows,!darwin
package main
import (
"fmt"
"net"
"os"
"syscall"
)
/* Borrowed from https://github.com/udhos/nexthop/ - Thanks! */
func udpConn(laddr *net.UDPAddr, ifname string) (*net.UDPConn, error) {
if laddr == nil {
laddr = &net.UDPAddr{IP: net.IPv4zero, Port: 0}
}
s, err1 := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, syscall.IPPROTO_UDP)
if err1 != nil {
return nil, fmt.Errorf("Could not create socket(laddr=%v,ifname=%s): %v", laddr, ifname, err1)
}
if err := syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1); err != nil {
syscall.Close(s)
return nil, fmt.Errorf("Could not set reuse addr socket(laddr=%v,ifname=%s): %v", laddr, ifname, err)
}
if ifname != "" {
if err := syscall.SetsockoptString(s, syscall.SOL_SOCKET, syscall.SO_BINDTODEVICE, ifname); err != nil {
syscall.Close(s)
return nil, fmt.Errorf("Could not bind to device socket(laddr=%v, ifname=%s): %v", laddr, ifname, err)
}
}
lsa := syscall.SockaddrInet4{Port: laddr.Port}
copy(lsa.Addr[:], laddr.IP.To4())
if err := syscall.Bind(s, &lsa); err != nil {
syscall.Close(s)
return nil, fmt.Errorf("Could not bind socket to address %v: %v", laddr, err)
}
f := os.NewFile(uintptr(s), "")
c, err2 := net.FilePacketConn(f)
f.Close()
if err2 != nil {
syscall.Close(s)
return nil, fmt.Errorf("Could not get packet connection for socket(laddr=%v,ifname=%s): %v", laddr, ifname, err2)
}
return c.(*net.UDPConn), nil
}