Package gns provides golang bindings for the GameNetworkingSockets library.
- Connection-oriented API (like TCP)
- ... but message-oriented (like UDP), not stream-oriented.
- Supports both reliable and unreliable message types
- Messages can be larger than underlying MTU. The protocol performs fragmentation, reassembly, and retransmission for reliable messages.
- Encryption. AES-GCM-256 per packet, Curve25519 for key exchange and cert signatures. The details for shared key derivation and per-packet IV are based on the design used by Google's QUIC protocol.
- Tools for simulating loss and detailed stats measurement.
- IPv4 + IPv6
- Support for dynamic/static linking
- API documentation available via
godoc - Compatible with net.Conn and net.Listener
func Example() {
// GameNetworkingSockets uses a fixed transmission rate, set to 512K/s
cfg := gns.ConfigMap{
gns.ConfigSendRateMin: 512 * 1024,
gns.ConfigSendRateMax: 512 * 1024,
}
l, err := gns.Listen(&net.UDPAddr{IP: net.IP{127, 0, 0, 1}}, cfg)
if err != nil {
log.Fatal("Listen: ", err)
}
defer l.Close()
gns.SetGlobalConfigValue(gns.ConfigFakePacketLagRecv, 10.0)
gns.SetGlobalConfigValue(gns.ConfigFakePacketLagSend, 10.0)
gns.SetGlobalConfigValue(gns.ConfigFakePacketLossRecv, 5.0)
gns.SetGlobalConfigValue(gns.ConfigFakePacketLossSend, 5.0)
// send a burst of 2MiB random bytes with 20ms lag and ~10% packet loss
var in [2 * 1024 * 1024]byte
rand.Read(in[:])
go func() {
c, err := gns.Dial(l.Addr().(*net.UDPAddr), cfg)
if err != nil {
log.Fatal("Dial: ", err)
}
defer c.Close()
// Linger for as long as it takes
c.SetLinger(-1)
if _, err := io.Copy(c, bytes.NewReader(in[:])); err != nil {
log.Fatal("Copy: ", err)
}
}()
conn, err := l.AcceptGNS()
if err != nil {
log.Fatal("Accept: ", err)
}
defer conn.Close()
out, err := ioutil.ReadAll(conn)
if err != nil {
log.Fatal("Read: ", err)
}
fmt.Println("Compare(in, out) ==", bytes.Compare(out, in[:]) == 0)
// Output: Compare(in, out) == true
}