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gather.go
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gather.go
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package nat
import (
"errors"
"fmt"
"net"
"strconv"
"strings"
"time"
)
var lanNets = []*net.IPNet{
{net.IPv4(10, 0, 0, 0), net.CIDRMask(8, 32)},
{net.IPv4(172, 16, 0, 0), net.CIDRMask(12, 32)},
{net.IPv4(192, 168, 0, 0), net.CIDRMask(16, 32)},
{net.ParseIP("fc00"), net.CIDRMask(7, 128)},
}
type candidate struct {
Addr *net.UDPAddr
}
func (c candidate) String() string {
return fmt.Sprintf("%v", c.Addr)
}
func (c candidate) Equal(c2 candidate) bool {
return c.Addr.IP.Equal(c2.Addr.IP) && c.Addr.Port == c2.Addr.Port
}
func pruneDups(cs []candidate) []candidate {
ret := make([]candidate, 0, len(cs))
for _, c := range cs {
unique := true
for _, c2 := range ret {
if c.Equal(c2) {
unique = false
break
}
}
if unique {
ret = append(ret, c)
}
}
return ret
}
func GatherCandidates(sock *net.UDPConn, outIpList string, udpAddr string) ([]candidate, error) {
laddr := sock.LocalAddr().(*net.UDPAddr)
ret := []candidate{}
switch {
case laddr.IP.IsLoopback():
return nil, errors.New("Connecting over loopback not supported")
case laddr.IP.IsUnspecified():
addrs, err := net.InterfaceAddrs()
if err != nil {
return nil, err
}
for _, addr := range addrs {
ip, ok := addr.(*net.IPNet)
if ok && ip.IP.IsGlobalUnicast() {
ret = append(ret, candidate{&net.UDPAddr{IP: ip.IP, Port: laddr.Port}})
}
}
default:
ret = append(ret, candidate{laddr})
}
addip := func(ipStr string, port int) {
ip := net.ParseIP(ipStr)
if port == 0 {
port = laddr.Port
}
bHave := false
for _, info := range ret {
if info.Addr.IP.Equal(ip) && info.Addr.Port == port {
bHave = true
break
}
}
if !bHave {
ret = append(ret, candidate{&net.UDPAddr{IP: ip, Port: port}})
}
}
if udpAddr != "" {
addr, err := net.ResolveUDPAddr("udp", udpAddr)
if err != nil {
fmt.Println("Can't resolve udp address: ", err)
return nil, err
}
p2pAddr := ""
for i := 0; i < 5; i++ {
sock.WriteToUDP([]byte("makehole"), addr)
buf := make([]byte, 100)
sock.SetReadDeadline(time.Now().Add(time.Duration(1) * time.Second))
n, _, err := sock.ReadFromUDP(buf)
if err != nil {
fmt.Println("Can't ReadFromUDP: ", err, addr.String())
continue
} else {
p2pAddr = string(buf[0:n])
fmt.Println("read: ", p2pAddr)
break
}
}
addLen := len(p2pAddr)
if addLen > 0 {
tmparr := strings.Split(p2pAddr, ":")
var strip string
var strport string
strip, strport = tmparr[0], tmparr[1]
ip := net.ParseIP(strip)
port, _ := strconv.Atoi(strport)
ret = append(ret, candidate{&net.UDPAddr{IP: ip, Port: port}})
}
}
arr := strings.Split(outIpList, ";")
for _, ip := range arr {
addip(ip, 0)
}
/* for _, info := range ret {
log.Println("init ip:", info.Addr.String())
}*/
return ret, nil
}