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net/stun: convert to use net/netip.AddrPort

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Convert ParseResponse and Response to use netip.AddrPort instead of
net.IP and separate port.

Fixes #5281

Signed-off-by: Kris Brandow <kris.brandow@gmail.com>
This commit is contained in:
Kris Brandow
2022-08-12 15:22:05 -04:00
parent c3270af52b
commit 8f38afbf8e
7 changed files with 66 additions and 68 deletions
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64
net/stun/stun.go
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@ -11,6 +11,7 @@ import (
"errors"
"hash/crc32"
"net"
"net/netip"
)
const (
@ -151,20 +152,18 @@ func foreachAttr(b []byte, fn func(attrType uint16, a []byte) error) error {
}
// Response generates a binding response.
func Response(txID TxID, ip net.IP, port uint16) []byte {
if ip4 := ip.To4(); ip4 != nil {
ip = ip4
}
func Response(txID TxID, addrPort netip.AddrPort) []byte {
addr := addrPort.Addr()
var fam byte
switch len(ip) {
case net.IPv4len:
if addr.Is4() {
fam = 1
case net.IPv6len:
} else if addr.Is6() {
fam = 2
default:
} else {
return nil
}
attrsLen := 8 + len(ip)
attrsLen := 8 + addr.BitLen()/8
b := make([]byte, 0, headerLen+attrsLen)
// Header
@ -175,12 +174,13 @@ func Response(txID TxID, ip net.IP, port uint16) []byte {
// Attributes (well, one)
b = appendU16(b, attrXorMappedAddress)
b = appendU16(b, uint16(4+len(ip)))
b = appendU16(b, uint16(4+addr.BitLen()/8))
b = append(b,
0, // unused byte
fam)
b = appendU16(b, port^0x2112) // first half of magicCookie
for i, o := range []byte(ip) {
b = appendU16(b, addrPort.Port()^0x2112) // first half of magicCookie
ipa := addr.As16()
for i, o := range ipa[16-addr.BitLen()/8:] {
if i < 4 {
b = append(b, o^magicCookie[i])
} else {
@ -192,25 +192,23 @@ func Response(txID TxID, ip net.IP, port uint16) []byte {
// ParseResponse parses a successful binding response STUN packet.
// The IP address is extracted from the XOR-MAPPED-ADDRESS attribute.
// The returned addr slice is owned by the caller and does not alias b.
func ParseResponse(b []byte) (tID TxID, addr []byte, port uint16, err error) {
func ParseResponse(b []byte) (tID TxID, addr netip.AddrPort, err error) {
if !Is(b) {
return tID, nil, 0, ErrNotSTUN
return tID, netip.AddrPort{}, ErrNotSTUN
}
copy(tID[:], b[8:8+len(tID)])
if b[0] != 0x01 || b[1] != 0x01 {
return tID, nil, 0, ErrNotSuccessResponse
return tID, netip.AddrPort{}, ErrNotSuccessResponse
}
attrsLen := int(binary.BigEndian.Uint16(b[2:4]))
b = b[headerLen:] // remove STUN header
if attrsLen > len(b) {
return tID, nil, 0, ErrMalformedAttrs
return tID, netip.AddrPort{}, ErrMalformedAttrs
} else if len(b) > attrsLen {
b = b[:attrsLen] // trim trailing packet bytes
}
var addr6, fallbackAddr, fallbackAddr6 []byte
var port6, fallbackPort, fallbackPort6 uint16
var addr6, fallbackAddr, fallbackAddr6 netip.AddrPort
// Read through the attributes.
// The the addr+port reported by XOR-MAPPED-ADDRESS
@ -225,9 +223,9 @@ func ParseResponse(b []byte) (tID TxID, addr []byte, port uint16, err error) {
return err
}
if len(a) == 16 {
addr6, port6 = a, p
addr6 = netip.AddrPortFrom(netip.AddrFrom16(*(*[16]byte)([]byte(a))), p)
} else {
addr, port = a, p
addr = netip.AddrPortFrom(netip.AddrFrom4(*(*[4]byte)([]byte(a))), p)
}
case attrMappedAddress:
a, p, err := mappedAddress(attr)
@ -235,30 +233,30 @@ func ParseResponse(b []byte) (tID TxID, addr []byte, port uint16, err error) {
return ErrMalformedAttrs
}
if len(a) == 16 {
fallbackAddr6, fallbackPort6 = a, p
fallbackAddr6 = netip.AddrPortFrom(netip.AddrFrom16(*(*[16]byte)([]byte(a))), p)
} else {
fallbackAddr, fallbackPort = a, p
fallbackAddr = netip.AddrPortFrom(netip.AddrFrom4(*(*[4]byte)([]byte(a))), p)
}
}
return nil
}); err != nil {
return TxID{}, nil, 0, err
return TxID{}, netip.AddrPort{}, err
}
if addr != nil {
return tID, addr, port, nil
if addr.IsValid() {
return tID, addr, nil
}
if fallbackAddr != nil {
return tID, append([]byte{}, fallbackAddr...), fallbackPort, nil
if fallbackAddr.IsValid() {
return tID, fallbackAddr, nil
}
if addr6 != nil {
return tID, addr6, port6, nil
if addr6.IsValid() {
return tID, addr6, nil
}
if fallbackAddr6 != nil {
return tID, append([]byte{}, fallbackAddr6...), fallbackPort6, nil
if fallbackAddr6.IsValid() {
return tID, fallbackAddr6, nil
}
return tID, nil, 0, ErrMalformedAttrs
return tID, netip.AddrPort{}, ErrMalformedAttrs
}
func xorMappedAddress(tID TxID, b []byte) (addr []byte, port uint16, err error) {