minio/pkg/net/host.go

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// Copyright (c) 2015-2021 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package net
import (
"encoding/json"
"errors"
"net"
"regexp"
"strings"
)
var hostLabelRegexp = regexp.MustCompile("^[a-zA-Z0-9]([a-zA-Z0-9-]*[a-zA-Z0-9])?$")
// Host - holds network host IP/name and its port.
type Host struct {
Name string
Port Port
IsPortSet bool
}
// IsEmpty - returns whether Host is empty or not
func (host Host) IsEmpty() bool {
return host.Name == ""
}
// String - returns string representation of Host.
func (host Host) String() string {
if !host.IsPortSet {
return host.Name
}
return net.JoinHostPort(host.Name, host.Port.String())
}
// Equal - checks whether given host is equal or not.
func (host Host) Equal(compHost Host) bool {
return host.String() == compHost.String()
}
// MarshalJSON - converts Host into JSON data
func (host Host) MarshalJSON() ([]byte, error) {
return json.Marshal(host.String())
}
// UnmarshalJSON - parses data into Host.
func (host *Host) UnmarshalJSON(data []byte) (err error) {
var s string
if err = json.Unmarshal(data, &s); err != nil {
return err
}
// Allow empty string
if s == "" {
*host = Host{}
return nil
}
var h *Host
if h, err = ParseHost(s); err != nil {
return err
}
*host = *h
return nil
}
// ParseHost - parses string into Host
func ParseHost(s string) (*Host, error) {
if s == "" {
return nil, errors.New("invalid argument")
}
isValidHost := func(host string) bool {
if host == "" {
return true
}
if ip := net.ParseIP(host); ip != nil {
return true
}
// host is not a valid IPv4 or IPv6 address
// host may be a hostname
// refer https://en.wikipedia.org/wiki/Hostname#Restrictions_on_valid_host_names
// why checks are done like below
if len(host) < 1 || len(host) > 253 {
return false
}
for _, label := range strings.Split(host, ".") {
if len(label) < 1 || len(label) > 63 {
return false
}
if !hostLabelRegexp.MatchString(label) {
return false
}
}
return true
}
var port Port
var isPortSet bool
host, portStr, err := net.SplitHostPort(s)
if err != nil {
if !strings.Contains(err.Error(), "missing port in address") {
return nil, err
}
host = s
} else {
if port, err = ParsePort(portStr); err != nil {
return nil, err
}
isPortSet = true
}
if host != "" {
host, err = trimIPv6(host)
if err != nil {
return nil, err
}
}
// IPv6 requires a link-local address on every network interface.
// `%interface` should be preserved.
trimmedHost := host
if i := strings.LastIndex(trimmedHost, "%"); i > -1 {
// `%interface` can be skipped for validity check though.
trimmedHost = trimmedHost[:i]
}
if !isValidHost(trimmedHost) {
return nil, errors.New("invalid hostname")
}
return &Host{
Name: host,
Port: port,
IsPortSet: isPortSet,
}, nil
}
// IPv6 can be embedded with square brackets.
func trimIPv6(host string) (string, error) {
// `missing ']' in host` error is already handled in `SplitHostPort`
if host[len(host)-1] == ']' {
if host[0] != '[' {
return "", errors.New("missing '[' in host")
}
return host[1:][:len(host)-2], nil
}
return host, nil
}