upnp模块报错了 runtime error: invalid memory address or nil pointer dereference

[ghost]

Hi

I'm using your libraries for one of my projects, and I get this error from the libraries:

upnp模块报错了 runtime error: invalid memory address or nil

To riproduce it, I just run this code:

mapping_http := new(upnp.Upnp)
log.Printf("[INFO] UPnP on TCP %d...", ClusterPort)
if err := mapping_http.AddPortMapping(ClusterPort, ClusterPort, "TCP"); err == nil {
    log.Printf("[INFO] UPnP redirect TCP %d successful", ClusterPort)
} else {
    log.Printf("[WARNING] No UPnP on TCP %d: network UPnP-agnostic", ClusterPort)
}

log.Printf("[INFO] UPnP on UDP %d...", ClusterPort)

if err := mapping_http.AddPortMapping(ClusterPort, ClusterPort, "UDP"); err == nil {
    log.Printf("[INFO] UPnP redirect UDP %d successful", ClusterPort)
} else {
    log.Printf("[WARNING] No UPnP on UDP %d: network UPnP-agnostic", ClusterPort)
}

The complete log of this piece of code is:

2015/04/30 20:34:35 [INFO] UPnP on TCP 21000...
2015/04/30 20:35:05 upnp模块报错了 runtime error: invalid memory address or nil pointer dereference
2015/04/30 20:35:05 [INFO] UPnP redirect TCP 21000 successful
2015/04/30 20:35:05 [INFO] UPnP on UDP 21000...
2015/04/30 20:35:35 upnp模块报错了 runtime error: invalid memory address or nil pointer dereference
2015/04/30 20:35:35 [INFO] UPnP redirect UDP 21000 successful

as you can see, the port is opened and it returns no error. But it logs the message mentioned.