headscale/hscontrol/util/string.go

76 lines
1.9 KiB
Go

package util
import (
"crypto/rand"
"encoding/base64"
"fmt"
"strings"
"tailscale.com/tailcfg"
)
// GenerateRandomBytes returns securely generated random bytes.
// It will return an error if the system's secure random
// number generator fails to function correctly, in which
// case the caller should not continue.
func GenerateRandomBytes(n int) ([]byte, error) {
bytes := make([]byte, n)
// Note that err == nil only if we read len(b) bytes.
if _, err := rand.Read(bytes); err != nil {
return nil, err
}
return bytes, nil
}
// GenerateRandomStringURLSafe returns a URL-safe, base64 encoded
// securely generated random string.
// It will return an error if the system's secure random
// number generator fails to function correctly, in which
// case the caller should not continue.
func GenerateRandomStringURLSafe(n int) (string, error) {
b, err := GenerateRandomBytes(n)
return base64.RawURLEncoding.EncodeToString(b), err
}
// GenerateRandomStringDNSSafe returns a DNS-safe
// securely generated random string.
// It will return an error if the system's secure random
// number generator fails to function correctly, in which
// case the caller should not continue.
func GenerateRandomStringDNSSafe(size int) (string, error) {
var str string
var err error
for len(str) < size {
str, err = GenerateRandomStringURLSafe(size)
if err != nil {
return "", err
}
str = strings.ToLower(
strings.ReplaceAll(strings.ReplaceAll(str, "_", ""), "-", ""),
)
}
return str[:size], nil
}
func TailNodesToString(nodes []*tailcfg.Node) string {
temp := make([]string, len(nodes))
for index, node := range nodes {
temp[index] = node.Name
}
return fmt.Sprintf("[ %s ](%d)", strings.Join(temp, ", "), len(temp))
}
func TailMapResponseToString(resp tailcfg.MapResponse) string {
return fmt.Sprintf(
"{ Node: %s, Peers: %s }",
resp.Node.Name,
TailNodesToString(resp.Peers),
)
}