Function hostnameInSNI

handshake_client.go:996–1011

hostnameInSNI converts name into an appropriate hostname for SNI. Literal IP addresses and absolute FQDNs are not permitted as SNI values. See RFC 6066, Section 3.

(name string)

// Literal IP addresses and absolute FQDNs are not permitted as SNI values.
// See RFC 6066, Section 3.
func hostnameInSNI(name string) string {
	host := name
	if len(host) > 0 && host[0] == '[' && host[len(host)-1] == ']' {
		host = host[1 : len(host)-1]
	}
	if i := strings.LastIndex(host, "%"); i > 0 {
		host = host[:i]
	}
	if net.ParseIP(host) != nil {
		return ""
	}
	for len(name) > 0 && name[len(name)-1] == '.' {
		name = name[:len(name)-1]
	}
	return name
}