torrent/socket.go

129 lines
2.7 KiB
Go

package torrent
import (
"context"
"fmt"
"net"
"strconv"
"strings"
"github.com/anacrolix/missinggo"
)
type dialer interface {
dial(_ context.Context, addr string) (net.Conn, error)
}
type socket interface {
net.Listener
dialer
}
func listen(network, addr string) (socket, error) {
if isTcpNetwork(network) {
return listenTcp(network, addr)
} else if isUtpNetwork(network) {
return listenUtp(network, addr)
} else {
panic(fmt.Sprintf("unknown network %q", network))
}
}
func isTcpNetwork(s string) bool {
return strings.Contains(s, "tcp")
}
func isUtpNetwork(s string) bool {
return strings.Contains(s, "utp") || strings.Contains(s, "udp")
}
func listenTcp(network, address string) (s socket, err error) {
l, err := net.Listen(network, address)
if err != nil {
return
}
return tcpSocket{l}, nil
}
type tcpSocket struct {
net.Listener
}
func (me tcpSocket) dial(ctx context.Context, addr string) (net.Conn, error) {
return net.Dial(me.Addr().Network(), addr)
}
func setPort(addr string, port int) string {
host, _, err := net.SplitHostPort(addr)
if err != nil {
panic(err)
}
return net.JoinHostPort(host, strconv.FormatInt(int64(port), 10))
}
func listenAll(networks []string, getHost func(string) string, port int) ([]socket, error) {
if len(networks) == 0 {
return nil, nil
}
var nahs []networkAndHost
for _, n := range networks {
nahs = append(nahs, networkAndHost{n, getHost(n)})
}
for {
ss, retry, err := listenAllRetry(nahs, port)
if !retry {
return ss, err
}
}
}
type networkAndHost struct {
Network string
Host string
}
func listenAllRetry(nahs []networkAndHost, port int) (ss []socket, retry bool, err error) {
ss = make([]socket, 1, len(nahs))
portStr := strconv.FormatInt(int64(port), 10)
ss[0], err = listen(nahs[0].Network, net.JoinHostPort(nahs[0].Host, portStr))
if err != nil {
return nil, false, fmt.Errorf("first listen: %s", err)
}
defer func() {
if err != nil || retry {
for _, s := range ss {
s.Close()
}
ss = nil
}
}()
portStr = strconv.FormatInt(int64(missinggo.AddrPort(ss[0].Addr())), 10)
for _, nah := range nahs[1:] {
s, err := listen(nah.Network, net.JoinHostPort(nah.Host, portStr))
if err != nil {
return ss,
missinggo.IsAddrInUse(err) && port == 0,
fmt.Errorf("subsequent listen: %s", err)
}
ss = append(ss, s)
}
return
}
func listenUtp(network, addr string) (s socket, err error) {
us, err := NewUtpSocket(network, addr)
if err != nil {
return
}
return utpSocketSocket{us, network}, nil
}
type utpSocketSocket struct {
utpSocket
network string
}
func (me utpSocketSocket) dial(ctx context.Context, addr string) (net.Conn, error) {
return me.utpSocket.DialContext(ctx, me.network, addr)
}