Initial commit
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NI
276
application/commands/address.go
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276
application/commands/address.go
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// Sshwifty - A Web SSH client
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//
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// Copyright (C) 2019 Rui NI <nirui@gmx.com>
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as
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// published by the Free Software Foundation, either version 3 of the
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// License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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package commands
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import (
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"errors"
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"net"
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"strconv"
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"github.com/niruix/sshwifty/application/rw"
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)
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//Errors
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var (
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ErrAddressParseBufferTooSmallForHeader = errors.New(
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"Buffer space was too small to parse the address header")
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ErrAddressParseBufferTooSmallForIPv4 = errors.New(
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"Buffer space was too small to parse the IPv4 address")
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ErrAddressParseBufferTooSmallForIPv6 = errors.New(
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"Buffer space was too small to parse the IPv6 address")
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ErrAddressParseBufferTooSmallForHostName = errors.New(
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"Buffer space was too small to parse the hostname address")
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ErrAddressMarshalBufferTooSmall = errors.New(
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"Buffer space was too small to marshal the address")
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ErrAddressInvalidAddressType = errors.New(
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"Invalid address type")
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)
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// AddressType Type of the address
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type AddressType byte
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// Address types
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const (
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LoopbackAddr AddressType = 0x00
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IPv4Addr AddressType = 0x01
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IPv6Addr AddressType = 0x02
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HostNameAddr AddressType = 0x03
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)
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// Address data
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type Address struct {
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port uint16
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kind AddressType
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data []byte
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}
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// ParseAddress parses the reader and return an Address
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//
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// Address data format:
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// +-------------+--------------+---------------+
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// | 2 bytes | 1 byte | n bytes |
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// +-------------+--------------+---------------+
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// | Port number | Address type | Address data |
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// +-------------+--------------+---------------+
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//
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// Address types:
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// - LoopbackAddr: 00 Localhost, don't carry Address data
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// - IPv4Addr: 01 IPv4 Address, carries 4 bytes of Address data
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// - IPv6Addr: 10 IPv6 Address, carries 16 bytes Address data
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// - HostnameAddr: 11 Host name string, length of Address data is indicated
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// by the remainer of the byte (11-- ----). maxlen = 63
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//
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func ParseAddress(reader rw.ReaderFunc, buf []byte) (Address, error) {
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if len(buf) < 3 {
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return Address{}, ErrAddressParseBufferTooSmallForHeader
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}
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_, rErr := rw.ReadFull(reader, buf[:3])
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if rErr != nil {
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return Address{}, rErr
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}
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portNum := uint16(0)
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portNum |= uint16(buf[0])
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portNum <<= 8
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portNum |= uint16(buf[1])
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addrType := AddressType(buf[2] >> 6)
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var addrData []byte
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switch addrType {
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case LoopbackAddr:
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// Do nothing
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case IPv4Addr:
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if len(buf) < 4 {
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return Address{}, ErrAddressParseBufferTooSmallForIPv4
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}
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_, rErr := rw.ReadFull(reader, buf[:4])
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if rErr != nil {
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return Address{}, rErr
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}
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addrData = buf[:4]
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case IPv6Addr:
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if len(buf) < 16 {
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return Address{}, ErrAddressParseBufferTooSmallForIPv6
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}
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_, rErr := rw.ReadFull(reader, buf[:16])
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if rErr != nil {
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return Address{}, rErr
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}
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addrData = buf[:16]
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case HostNameAddr:
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addrDataLen := int(0x3f & buf[2])
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if len(buf) < addrDataLen {
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return Address{}, ErrAddressParseBufferTooSmallForHostName
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}
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_, rErr := rw.ReadFull(reader, buf[:addrDataLen])
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if rErr != nil {
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return Address{}, rErr
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}
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addrData = buf[:addrDataLen]
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default:
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return Address{}, ErrAddressInvalidAddressType
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}
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return Address{
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port: portNum,
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kind: addrType,
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data: addrData,
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}, nil
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}
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// NewAddress creates a new Address
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func NewAddress(addrType AddressType, data []byte, port uint16) Address {
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return Address{
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port: port,
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kind: addrType,
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data: data,
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}
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}
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// Type returns the type of the address
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func (a Address) Type() AddressType {
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return a.kind
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}
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// Data returns the address data
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func (a Address) Data() []byte {
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return a.data
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}
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// Port returns port number
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func (a Address) Port() uint16 {
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return a.port
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}
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// Marshal writes address data to the given b
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func (a Address) Marshal(b []byte) (int, error) {
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bLen := len(b)
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switch a.Type() {
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case LoopbackAddr:
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if bLen < 3 {
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return 0, ErrAddressMarshalBufferTooSmall
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}
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b[0] = byte(a.port >> 8)
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b[1] = byte(a.port)
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b[2] = byte(LoopbackAddr << 6)
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return 3, nil
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case IPv4Addr:
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if bLen < 7 {
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return 0, ErrAddressMarshalBufferTooSmall
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}
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b[0] = byte(a.port >> 8)
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b[1] = byte(a.port)
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b[2] = byte(IPv4Addr << 6)
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copy(b[3:], a.data)
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return 7, nil
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case IPv6Addr:
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if bLen < 19 {
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return 0, ErrAddressMarshalBufferTooSmall
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}
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b[0] = byte(a.port >> 8)
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b[1] = byte(a.port)
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b[2] = byte(IPv6Addr << 6)
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copy(b[3:], a.data)
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return 19, nil
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case HostNameAddr:
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hLen := len(a.data)
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if hLen > 0x3f {
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panic("Host name cannot longer than 0x3f")
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}
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if bLen < hLen+3 {
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return 0, ErrAddressMarshalBufferTooSmall
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}
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b[0] = byte(a.port >> 8)
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b[1] = byte(a.port)
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b[2] = byte(HostNameAddr << 6)
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b[2] |= byte(hLen)
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copy(b[3:], a.data)
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return hLen + 3, nil
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default:
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return 0, ErrAddressInvalidAddressType
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}
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}
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// String return the Address as string
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func (a Address) String() string {
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switch a.Type() {
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case LoopbackAddr:
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return net.JoinHostPort(
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"localhost",
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strconv.FormatUint(uint64(a.Port()), 10))
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case IPv4Addr:
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return net.JoinHostPort(
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net.IPv4(a.data[0], a.data[1], a.data[2], a.data[3]).String(),
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strconv.FormatUint(uint64(a.Port()), 10))
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case IPv6Addr:
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return net.JoinHostPort(
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net.IP(a.data[:net.IPv6len]).String(),
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strconv.FormatUint(uint64(a.Port()), 10))
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case HostNameAddr:
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return net.JoinHostPort(
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string(a.data),
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strconv.FormatUint(uint64(a.Port()), 10))
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default:
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panic("Unknown Address type")
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}
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}
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