blob: 1cd247c16fa2000e5aac06de649cf3a951b1fc80 [file] [log] [blame]
/*
* Copyright 2018-2023 Open Networking Foundation (ONF) and the ONF Contributors
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package common
import (
"fmt"
"math/rand"
"time"
)
// GetRandomSerialNumber returns a serial number formatted as "HOST:PORT"
func GetRandomSerialNumber() string {
rand.Seed(time.Now().UnixNano())
return fmt.Sprintf("%d.%d.%d.%d:%d",
rand.Intn(255),
rand.Intn(255),
rand.Intn(255),
rand.Intn(255),
rand.Intn(9000)+1000,
)
}
// GetRandomMacAddress returns a random mac address
func GetRandomMacAddress() string {
rand.Seed(time.Now().UnixNano())
return fmt.Sprintf("%02x:%02x:%02x:%02x:%02x:%02x",
rand.Intn(128),
rand.Intn(128),
rand.Intn(128),
rand.Intn(128),
rand.Intn(128),
rand.Intn(128),
)
}
const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
const (
letterIdxBits = 6 // 6 bits to represent a letter index
letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
letterIdxMax = 63 / letterIdxBits // # of letter indices fitting in 63 bits
)
var src = rand.NewSource(time.Now().UnixNano())
func GetRandomString(n int) string {
b := make([]byte, n)
// A src.Int63() generates 63 random bits, enough for letterIdxMax characters!
for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; {
if remain == 0 {
cache, remain = src.Int63(), letterIdxMax
}
if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
b[i] = letterBytes[idx]
i--
}
cache >>= letterIdxBits
remain--
}
return string(b)
}