//ClientList returns a struct where the clients will be managed.
func ClientList() *clientList {
cl := clientList{}
cl.nextId = 0
cl.list = make([]client, conf.MaxClients()) //The maximum number of clients
//is determined in the configuration file.
cl.numClients = 0
return &cl
}
//newClient saves a new client into the struct. userAgent is used
//to reduce the possibility of a phishing attack.
func (cl *clientList) newClient(userAgent []string) (uint32, uint32, error) {
if cl.numClients >= conf.MaxClients() {
return 0, 0, errors.New("It have reached the maximum number of clients")
}
//Search an available position in the clientLst
var id uint32 = cl.nextId
var found bool = false
for !found {
switch {
case id >= conf.MaxClients(): //If the 'index' is bigger than
//the maximum number of clients, it will be reset to zero
id = 0
case cl.list[id].occupied: //If the position is not available
id += 1
default: //The position is available
cl.nextId = id + 1 //It prepares nextId to the next time
found = true
}
}
//Use a random number as key
rand.Seed(time.Now().UTC().UnixNano())
var key uint32 = rand.Uint32()
var cli client = client{key, userAgent, true}
//Add the client to the list
cl.list[id] = cli
cl.numClients += 1
return id, key, nil
}
//IsLogged checks if a client is registered. It is true if error is "nil".
func (cl *clientList) isLogged(id uint32, key uint32, userAgent []string) error {
if id >= conf.MaxClients() {
return errors.New("Id is not valid")
}
client := cl.list[id]
if !client.occupied { //The position is free
return errors.New("Client does not exist")
} else if client.key != key {
return errors.New("Incorrect key")
} else if eq := reflect.DeepEqual(userAgent, client.userAgent); !eq {
return errors.New("UserAgent not equal")
} else {
//Client is logged
return nil
}
}