croc/vendor/github.com/schollz/peerdiscovery/utils.go

71 lines
1.9 KiB
Go

package peerdiscovery
import (
math_rand "math/rand"
"net"
"strings"
"time"
)
// GetLocalIP returns the local ip address
func GetLocalIP() string {
addrs, err := net.InterfaceAddrs()
if err != nil {
return "localhost"
}
bestIP := "localhost"
for _, address := range addrs {
// check the address type and if it is not a loopback the display it
if ipnet, ok := address.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
if ipnet.IP.To4() != nil && (strings.Contains(ipnet.IP.String(), "192.168.1") || strings.Contains(ipnet.IP.String(), "192.168")) {
return ipnet.IP.String()
}
}
}
return bestIP
}
// GetLocalIPs returns the local ip address
func GetLocalIPs() (ips map[string]struct{}) {
ips = make(map[string]struct{})
ips["localhost"] = struct{}{}
ips["127.0.0.1"] = struct{}{}
addrs, err := net.InterfaceAddrs()
if err != nil {
return
}
for _, address := range addrs {
ips[strings.Split(address.String(), "/")[0]] = struct{}{}
}
return
}
// src is seeds the random generator for generating random strings
var src = math_rand.NewSource(time.Now().UnixNano())
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
)
// RandStringBytesMaskImprSrc prints a random string
func RandStringBytesMaskImprSrc(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)
}