/
connv4.go
57 lines (46 loc) · 1.14 KB
/
connv4.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
48
49
50
51
52
53
54
55
56
57
package internal
import (
"fmt"
"golang.org/x/net/ipv4"
"net"
)
type ipv4PacketConn struct {
*ipv4.PacketConn
}
func (c *ipv4PacketConn) ReadFrom(b []byte) (int, net.Addr, error) {
n, _, addr, err := c.PacketConn.ReadFrom(b)
return n, addr, err
}
func (c *ipv4PacketConn) WriteTo(b []byte, dst net.Addr) (int, error) {
return c.PacketConn.WriteTo(b, nil, dst)
}
type IPv4PacketConnFactory struct {
Group *net.UDPAddr
}
func (f *IPv4PacketConnFactory) MakeUDPSocket(ifaces []net.Interface, addr *net.UDPAddr, ttl int) (net.PacketConn, error) {
conn, err := net.ListenUDP("udp4", addr)
if err != nil {
return nil, err
}
pConn := ipv4.NewPacketConn(conn)
if ttl >= 0 {
if err := pConn.SetMulticastTTL(ttl); err != nil {
pConn.Close()
return nil, err
}
}
if f.Group != nil {
pConn.SetMulticastLoopback(true)
var errCount = 0
for i := range ifaces {
if nErr := pConn.JoinGroup(&ifaces[i], f.Group); nErr != nil {
errCount += 1
}
}
if errCount == len(ifaces) {
pConn.Close()
return nil, fmt.Errorf("failed to join multicast group on all interfaces")
}
}
return &ipv4PacketConn{PacketConn: pConn}, nil
}