mirror of
https://github.com/go-gitea/gitea.git
synced 2024-12-14 16:49:19 +08:00
834 lines
22 KiB
Go
Vendored
834 lines
22 KiB
Go
Vendored
package dns
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import (
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"encoding/base32"
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"encoding/base64"
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"encoding/binary"
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"encoding/hex"
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"net"
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"sort"
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"strings"
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)
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// helper functions called from the generated zmsg.go
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// These function are named after the tag to help pack/unpack, if there is no tag it is the name
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// of the type they pack/unpack (string, int, etc). We prefix all with unpackData or packData, so packDataA or
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// packDataDomainName.
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func unpackDataA(msg []byte, off int) (net.IP, int, error) {
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if off+net.IPv4len > len(msg) {
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return nil, len(msg), &Error{err: "overflow unpacking a"}
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}
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a := append(make(net.IP, 0, net.IPv4len), msg[off:off+net.IPv4len]...)
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off += net.IPv4len
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return a, off, nil
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}
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func packDataA(a net.IP, msg []byte, off int) (int, error) {
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switch len(a) {
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case net.IPv4len, net.IPv6len:
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// It must be a slice of 4, even if it is 16, we encode only the first 4
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if off+net.IPv4len > len(msg) {
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return len(msg), &Error{err: "overflow packing a"}
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}
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copy(msg[off:], a.To4())
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off += net.IPv4len
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case 0:
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// Allowed, for dynamic updates.
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default:
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return len(msg), &Error{err: "overflow packing a"}
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}
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return off, nil
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}
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func unpackDataAAAA(msg []byte, off int) (net.IP, int, error) {
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if off+net.IPv6len > len(msg) {
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return nil, len(msg), &Error{err: "overflow unpacking aaaa"}
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}
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aaaa := append(make(net.IP, 0, net.IPv6len), msg[off:off+net.IPv6len]...)
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off += net.IPv6len
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return aaaa, off, nil
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}
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func packDataAAAA(aaaa net.IP, msg []byte, off int) (int, error) {
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switch len(aaaa) {
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case net.IPv6len:
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if off+net.IPv6len > len(msg) {
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return len(msg), &Error{err: "overflow packing aaaa"}
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}
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copy(msg[off:], aaaa)
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off += net.IPv6len
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case 0:
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// Allowed, dynamic updates.
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default:
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return len(msg), &Error{err: "overflow packing aaaa"}
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}
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return off, nil
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}
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// unpackHeader unpacks an RR header, returning the offset to the end of the header and a
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// re-sliced msg according to the expected length of the RR.
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func unpackHeader(msg []byte, off int) (rr RR_Header, off1 int, truncmsg []byte, err error) {
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hdr := RR_Header{}
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if off == len(msg) {
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return hdr, off, msg, nil
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}
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hdr.Name, off, err = UnpackDomainName(msg, off)
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if err != nil {
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return hdr, len(msg), msg, err
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}
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hdr.Rrtype, off, err = unpackUint16(msg, off)
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if err != nil {
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return hdr, len(msg), msg, err
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}
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hdr.Class, off, err = unpackUint16(msg, off)
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if err != nil {
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return hdr, len(msg), msg, err
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}
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hdr.Ttl, off, err = unpackUint32(msg, off)
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if err != nil {
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return hdr, len(msg), msg, err
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}
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hdr.Rdlength, off, err = unpackUint16(msg, off)
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if err != nil {
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return hdr, len(msg), msg, err
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}
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msg, err = truncateMsgFromRdlength(msg, off, hdr.Rdlength)
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return hdr, off, msg, err
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}
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// packHeader packs an RR header, returning the offset to the end of the header.
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// See PackDomainName for documentation about the compression.
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func (hdr RR_Header) packHeader(msg []byte, off int, compression compressionMap, compress bool) (int, error) {
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if off == len(msg) {
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return off, nil
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}
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off, err := packDomainName(hdr.Name, msg, off, compression, compress)
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if err != nil {
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return len(msg), err
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}
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off, err = packUint16(hdr.Rrtype, msg, off)
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if err != nil {
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return len(msg), err
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}
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off, err = packUint16(hdr.Class, msg, off)
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if err != nil {
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return len(msg), err
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}
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off, err = packUint32(hdr.Ttl, msg, off)
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if err != nil {
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return len(msg), err
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}
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off, err = packUint16(0, msg, off) // The RDLENGTH field will be set later in packRR.
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if err != nil {
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return len(msg), err
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}
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return off, nil
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}
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// helper helper functions.
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// truncateMsgFromRdLength truncates msg to match the expected length of the RR.
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// Returns an error if msg is smaller than the expected size.
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func truncateMsgFromRdlength(msg []byte, off int, rdlength uint16) (truncmsg []byte, err error) {
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lenrd := off + int(rdlength)
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if lenrd > len(msg) {
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return msg, &Error{err: "overflowing header size"}
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}
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return msg[:lenrd], nil
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}
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var base32HexNoPadEncoding = base32.HexEncoding.WithPadding(base32.NoPadding)
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func fromBase32(s []byte) (buf []byte, err error) {
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for i, b := range s {
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if b >= 'a' && b <= 'z' {
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s[i] = b - 32
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}
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}
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buflen := base32HexNoPadEncoding.DecodedLen(len(s))
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buf = make([]byte, buflen)
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n, err := base32HexNoPadEncoding.Decode(buf, s)
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buf = buf[:n]
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return
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}
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func toBase32(b []byte) string {
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return base32HexNoPadEncoding.EncodeToString(b)
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}
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func fromBase64(s []byte) (buf []byte, err error) {
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buflen := base64.StdEncoding.DecodedLen(len(s))
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buf = make([]byte, buflen)
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n, err := base64.StdEncoding.Decode(buf, s)
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buf = buf[:n]
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return
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}
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func toBase64(b []byte) string { return base64.StdEncoding.EncodeToString(b) }
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// dynamicUpdate returns true if the Rdlength is zero.
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func noRdata(h RR_Header) bool { return h.Rdlength == 0 }
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func unpackUint8(msg []byte, off int) (i uint8, off1 int, err error) {
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if off+1 > len(msg) {
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return 0, len(msg), &Error{err: "overflow unpacking uint8"}
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}
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return msg[off], off + 1, nil
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}
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func packUint8(i uint8, msg []byte, off int) (off1 int, err error) {
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if off+1 > len(msg) {
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return len(msg), &Error{err: "overflow packing uint8"}
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}
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msg[off] = i
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return off + 1, nil
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}
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func unpackUint16(msg []byte, off int) (i uint16, off1 int, err error) {
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if off+2 > len(msg) {
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return 0, len(msg), &Error{err: "overflow unpacking uint16"}
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}
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return binary.BigEndian.Uint16(msg[off:]), off + 2, nil
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}
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func packUint16(i uint16, msg []byte, off int) (off1 int, err error) {
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if off+2 > len(msg) {
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return len(msg), &Error{err: "overflow packing uint16"}
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}
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binary.BigEndian.PutUint16(msg[off:], i)
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return off + 2, nil
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}
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func unpackUint32(msg []byte, off int) (i uint32, off1 int, err error) {
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if off+4 > len(msg) {
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return 0, len(msg), &Error{err: "overflow unpacking uint32"}
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}
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return binary.BigEndian.Uint32(msg[off:]), off + 4, nil
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}
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func packUint32(i uint32, msg []byte, off int) (off1 int, err error) {
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if off+4 > len(msg) {
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return len(msg), &Error{err: "overflow packing uint32"}
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}
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binary.BigEndian.PutUint32(msg[off:], i)
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return off + 4, nil
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}
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func unpackUint48(msg []byte, off int) (i uint64, off1 int, err error) {
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if off+6 > len(msg) {
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return 0, len(msg), &Error{err: "overflow unpacking uint64 as uint48"}
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}
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// Used in TSIG where the last 48 bits are occupied, so for now, assume a uint48 (6 bytes)
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i = uint64(msg[off])<<40 | uint64(msg[off+1])<<32 | uint64(msg[off+2])<<24 | uint64(msg[off+3])<<16 |
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uint64(msg[off+4])<<8 | uint64(msg[off+5])
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off += 6
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return i, off, nil
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}
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func packUint48(i uint64, msg []byte, off int) (off1 int, err error) {
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if off+6 > len(msg) {
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return len(msg), &Error{err: "overflow packing uint64 as uint48"}
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}
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msg[off] = byte(i >> 40)
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msg[off+1] = byte(i >> 32)
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msg[off+2] = byte(i >> 24)
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msg[off+3] = byte(i >> 16)
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msg[off+4] = byte(i >> 8)
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msg[off+5] = byte(i)
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off += 6
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return off, nil
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}
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func unpackUint64(msg []byte, off int) (i uint64, off1 int, err error) {
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if off+8 > len(msg) {
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return 0, len(msg), &Error{err: "overflow unpacking uint64"}
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}
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return binary.BigEndian.Uint64(msg[off:]), off + 8, nil
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}
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func packUint64(i uint64, msg []byte, off int) (off1 int, err error) {
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if off+8 > len(msg) {
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return len(msg), &Error{err: "overflow packing uint64"}
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}
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binary.BigEndian.PutUint64(msg[off:], i)
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off += 8
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return off, nil
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}
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func unpackString(msg []byte, off int) (string, int, error) {
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if off+1 > len(msg) {
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return "", off, &Error{err: "overflow unpacking txt"}
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}
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l := int(msg[off])
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off++
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if off+l > len(msg) {
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return "", off, &Error{err: "overflow unpacking txt"}
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}
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var s strings.Builder
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consumed := 0
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for i, b := range msg[off : off+l] {
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switch {
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case b == '"' || b == '\\':
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if consumed == 0 {
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s.Grow(l * 2)
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}
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s.Write(msg[off+consumed : off+i])
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s.WriteByte('\\')
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s.WriteByte(b)
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consumed = i + 1
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case b < ' ' || b > '~': // unprintable
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if consumed == 0 {
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s.Grow(l * 2)
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}
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s.Write(msg[off+consumed : off+i])
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s.WriteString(escapeByte(b))
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consumed = i + 1
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}
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}
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if consumed == 0 { // no escaping needed
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return string(msg[off : off+l]), off + l, nil
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}
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s.Write(msg[off+consumed : off+l])
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return s.String(), off + l, nil
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}
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func packString(s string, msg []byte, off int) (int, error) {
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txtTmp := make([]byte, 256*4+1)
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off, err := packTxtString(s, msg, off, txtTmp)
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if err != nil {
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return len(msg), err
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}
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return off, nil
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}
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func unpackStringBase32(msg []byte, off, end int) (string, int, error) {
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if end > len(msg) {
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return "", len(msg), &Error{err: "overflow unpacking base32"}
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}
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s := toBase32(msg[off:end])
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return s, end, nil
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}
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func packStringBase32(s string, msg []byte, off int) (int, error) {
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b32, err := fromBase32([]byte(s))
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if err != nil {
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return len(msg), err
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}
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if off+len(b32) > len(msg) {
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return len(msg), &Error{err: "overflow packing base32"}
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}
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copy(msg[off:off+len(b32)], b32)
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off += len(b32)
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return off, nil
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}
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func unpackStringBase64(msg []byte, off, end int) (string, int, error) {
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// Rest of the RR is base64 encoded value, so we don't need an explicit length
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// to be set. Thus far all RR's that have base64 encoded fields have those as their
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// last one. What we do need is the end of the RR!
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if end > len(msg) {
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return "", len(msg), &Error{err: "overflow unpacking base64"}
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}
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s := toBase64(msg[off:end])
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return s, end, nil
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}
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func packStringBase64(s string, msg []byte, off int) (int, error) {
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b64, err := fromBase64([]byte(s))
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if err != nil {
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return len(msg), err
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}
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if off+len(b64) > len(msg) {
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return len(msg), &Error{err: "overflow packing base64"}
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}
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copy(msg[off:off+len(b64)], b64)
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off += len(b64)
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return off, nil
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}
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func unpackStringHex(msg []byte, off, end int) (string, int, error) {
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// Rest of the RR is hex encoded value, so we don't need an explicit length
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// to be set. NSEC and TSIG have hex fields with a length field.
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// What we do need is the end of the RR!
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if end > len(msg) {
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return "", len(msg), &Error{err: "overflow unpacking hex"}
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}
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s := hex.EncodeToString(msg[off:end])
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return s, end, nil
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}
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func packStringHex(s string, msg []byte, off int) (int, error) {
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h, err := hex.DecodeString(s)
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if err != nil {
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return len(msg), err
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}
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if off+len(h) > len(msg) {
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return len(msg), &Error{err: "overflow packing hex"}
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}
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copy(msg[off:off+len(h)], h)
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off += len(h)
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return off, nil
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}
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func unpackStringAny(msg []byte, off, end int) (string, int, error) {
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if end > len(msg) {
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return "", len(msg), &Error{err: "overflow unpacking anything"}
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}
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return string(msg[off:end]), end, nil
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}
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func packStringAny(s string, msg []byte, off int) (int, error) {
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if off+len(s) > len(msg) {
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return len(msg), &Error{err: "overflow packing anything"}
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}
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copy(msg[off:off+len(s)], s)
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off += len(s)
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return off, nil
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}
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func unpackStringTxt(msg []byte, off int) ([]string, int, error) {
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txt, off, err := unpackTxt(msg, off)
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if err != nil {
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return nil, len(msg), err
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}
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return txt, off, nil
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}
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func packStringTxt(s []string, msg []byte, off int) (int, error) {
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txtTmp := make([]byte, 256*4+1) // If the whole string consists out of \DDD we need this many.
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off, err := packTxt(s, msg, off, txtTmp)
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if err != nil {
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return len(msg), err
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}
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return off, nil
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}
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|
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func unpackDataOpt(msg []byte, off int) ([]EDNS0, int, error) {
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var edns []EDNS0
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Option:
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var code uint16
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if off+4 > len(msg) {
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return nil, len(msg), &Error{err: "overflow unpacking opt"}
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}
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code = binary.BigEndian.Uint16(msg[off:])
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off += 2
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optlen := binary.BigEndian.Uint16(msg[off:])
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off += 2
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if off+int(optlen) > len(msg) {
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return nil, len(msg), &Error{err: "overflow unpacking opt"}
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}
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e := makeDataOpt(code)
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if err := e.unpack(msg[off : off+int(optlen)]); err != nil {
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return nil, len(msg), err
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}
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edns = append(edns, e)
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off += int(optlen)
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|
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if off < len(msg) {
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goto Option
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}
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return edns, off, nil
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}
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|
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func makeDataOpt(code uint16) EDNS0 {
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switch code {
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case EDNS0NSID:
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return new(EDNS0_NSID)
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case EDNS0SUBNET:
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return new(EDNS0_SUBNET)
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case EDNS0COOKIE:
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return new(EDNS0_COOKIE)
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case EDNS0EXPIRE:
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return new(EDNS0_EXPIRE)
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case EDNS0UL:
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return new(EDNS0_UL)
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case EDNS0LLQ:
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return new(EDNS0_LLQ)
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case EDNS0DAU:
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return new(EDNS0_DAU)
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case EDNS0DHU:
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return new(EDNS0_DHU)
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case EDNS0N3U:
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return new(EDNS0_N3U)
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case EDNS0PADDING:
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return new(EDNS0_PADDING)
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default:
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e := new(EDNS0_LOCAL)
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e.Code = code
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return e
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}
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}
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|
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func packDataOpt(options []EDNS0, msg []byte, off int) (int, error) {
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for _, el := range options {
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b, err := el.pack()
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if err != nil || off+4 > len(msg) {
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return len(msg), &Error{err: "overflow packing opt"}
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}
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binary.BigEndian.PutUint16(msg[off:], el.Option()) // Option code
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binary.BigEndian.PutUint16(msg[off+2:], uint16(len(b))) // Length
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off += 4
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if off+len(b) > len(msg) {
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return len(msg), &Error{err: "overflow packing opt"}
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}
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// Actual data
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copy(msg[off:off+len(b)], b)
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off += len(b)
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}
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return off, nil
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}
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|
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func unpackStringOctet(msg []byte, off int) (string, int, error) {
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s := string(msg[off:])
|
|
return s, len(msg), nil
|
|
}
|
|
|
|
func packStringOctet(s string, msg []byte, off int) (int, error) {
|
|
txtTmp := make([]byte, 256*4+1)
|
|
off, err := packOctetString(s, msg, off, txtTmp)
|
|
if err != nil {
|
|
return len(msg), err
|
|
}
|
|
return off, nil
|
|
}
|
|
|
|
func unpackDataNsec(msg []byte, off int) ([]uint16, int, error) {
|
|
var nsec []uint16
|
|
length, window, lastwindow := 0, 0, -1
|
|
for off < len(msg) {
|
|
if off+2 > len(msg) {
|
|
return nsec, len(msg), &Error{err: "overflow unpacking nsecx"}
|
|
}
|
|
window = int(msg[off])
|
|
length = int(msg[off+1])
|
|
off += 2
|
|
if window <= lastwindow {
|
|
// RFC 4034: Blocks are present in the NSEC RR RDATA in
|
|
// increasing numerical order.
|
|
return nsec, len(msg), &Error{err: "out of order NSEC block"}
|
|
}
|
|
if length == 0 {
|
|
// RFC 4034: Blocks with no types present MUST NOT be included.
|
|
return nsec, len(msg), &Error{err: "empty NSEC block"}
|
|
}
|
|
if length > 32 {
|
|
return nsec, len(msg), &Error{err: "NSEC block too long"}
|
|
}
|
|
if off+length > len(msg) {
|
|
return nsec, len(msg), &Error{err: "overflowing NSEC block"}
|
|
}
|
|
|
|
// Walk the bytes in the window and extract the type bits
|
|
for j, b := range msg[off : off+length] {
|
|
// Check the bits one by one, and set the type
|
|
if b&0x80 == 0x80 {
|
|
nsec = append(nsec, uint16(window*256+j*8+0))
|
|
}
|
|
if b&0x40 == 0x40 {
|
|
nsec = append(nsec, uint16(window*256+j*8+1))
|
|
}
|
|
if b&0x20 == 0x20 {
|
|
nsec = append(nsec, uint16(window*256+j*8+2))
|
|
}
|
|
if b&0x10 == 0x10 {
|
|
nsec = append(nsec, uint16(window*256+j*8+3))
|
|
}
|
|
if b&0x8 == 0x8 {
|
|
nsec = append(nsec, uint16(window*256+j*8+4))
|
|
}
|
|
if b&0x4 == 0x4 {
|
|
nsec = append(nsec, uint16(window*256+j*8+5))
|
|
}
|
|
if b&0x2 == 0x2 {
|
|
nsec = append(nsec, uint16(window*256+j*8+6))
|
|
}
|
|
if b&0x1 == 0x1 {
|
|
nsec = append(nsec, uint16(window*256+j*8+7))
|
|
}
|
|
}
|
|
off += length
|
|
lastwindow = window
|
|
}
|
|
return nsec, off, nil
|
|
}
|
|
|
|
// typeBitMapLen is a helper function which computes the "maximum" length of
|
|
// a the NSEC Type BitMap field.
|
|
func typeBitMapLen(bitmap []uint16) int {
|
|
var l int
|
|
var lastwindow, lastlength uint16
|
|
for _, t := range bitmap {
|
|
window := t / 256
|
|
length := (t-window*256)/8 + 1
|
|
if window > lastwindow && lastlength != 0 { // New window, jump to the new offset
|
|
l += int(lastlength) + 2
|
|
lastlength = 0
|
|
}
|
|
if window < lastwindow || length < lastlength {
|
|
// packDataNsec would return Error{err: "nsec bits out of order"} here, but
|
|
// when computing the length, we want do be liberal.
|
|
continue
|
|
}
|
|
lastwindow, lastlength = window, length
|
|
}
|
|
l += int(lastlength) + 2
|
|
return l
|
|
}
|
|
|
|
func packDataNsec(bitmap []uint16, msg []byte, off int) (int, error) {
|
|
if len(bitmap) == 0 {
|
|
return off, nil
|
|
}
|
|
var lastwindow, lastlength uint16
|
|
for _, t := range bitmap {
|
|
window := t / 256
|
|
length := (t-window*256)/8 + 1
|
|
if window > lastwindow && lastlength != 0 { // New window, jump to the new offset
|
|
off += int(lastlength) + 2
|
|
lastlength = 0
|
|
}
|
|
if window < lastwindow || length < lastlength {
|
|
return len(msg), &Error{err: "nsec bits out of order"}
|
|
}
|
|
if off+2+int(length) > len(msg) {
|
|
return len(msg), &Error{err: "overflow packing nsec"}
|
|
}
|
|
// Setting the window #
|
|
msg[off] = byte(window)
|
|
// Setting the octets length
|
|
msg[off+1] = byte(length)
|
|
// Setting the bit value for the type in the right octet
|
|
msg[off+1+int(length)] |= byte(1 << (7 - t%8))
|
|
lastwindow, lastlength = window, length
|
|
}
|
|
off += int(lastlength) + 2
|
|
return off, nil
|
|
}
|
|
|
|
func unpackDataSVCB(msg []byte, off int) ([]SVCBKeyValue, int, error) {
|
|
var xs []SVCBKeyValue
|
|
var code uint16
|
|
var length uint16
|
|
var err error
|
|
for off < len(msg) {
|
|
code, off, err = unpackUint16(msg, off)
|
|
if err != nil {
|
|
return nil, len(msg), &Error{err: "overflow unpacking SVCB"}
|
|
}
|
|
length, off, err = unpackUint16(msg, off)
|
|
if err != nil || off+int(length) > len(msg) {
|
|
return nil, len(msg), &Error{err: "overflow unpacking SVCB"}
|
|
}
|
|
e := makeSVCBKeyValue(SVCBKey(code))
|
|
if e == nil {
|
|
return nil, len(msg), &Error{err: "bad SVCB key"}
|
|
}
|
|
if err := e.unpack(msg[off : off+int(length)]); err != nil {
|
|
return nil, len(msg), err
|
|
}
|
|
if len(xs) > 0 && e.Key() <= xs[len(xs)-1].Key() {
|
|
return nil, len(msg), &Error{err: "SVCB keys not in strictly increasing order"}
|
|
}
|
|
xs = append(xs, e)
|
|
off += int(length)
|
|
}
|
|
return xs, off, nil
|
|
}
|
|
|
|
func packDataSVCB(pairs []SVCBKeyValue, msg []byte, off int) (int, error) {
|
|
pairs = append([]SVCBKeyValue(nil), pairs...)
|
|
sort.Slice(pairs, func(i, j int) bool {
|
|
return pairs[i].Key() < pairs[j].Key()
|
|
})
|
|
prev := svcb_RESERVED
|
|
for _, el := range pairs {
|
|
if el.Key() == prev {
|
|
return len(msg), &Error{err: "repeated SVCB keys are not allowed"}
|
|
}
|
|
prev = el.Key()
|
|
packed, err := el.pack()
|
|
if err != nil {
|
|
return len(msg), err
|
|
}
|
|
off, err = packUint16(uint16(el.Key()), msg, off)
|
|
if err != nil {
|
|
return len(msg), &Error{err: "overflow packing SVCB"}
|
|
}
|
|
off, err = packUint16(uint16(len(packed)), msg, off)
|
|
if err != nil || off+len(packed) > len(msg) {
|
|
return len(msg), &Error{err: "overflow packing SVCB"}
|
|
}
|
|
copy(msg[off:off+len(packed)], packed)
|
|
off += len(packed)
|
|
}
|
|
return off, nil
|
|
}
|
|
|
|
func unpackDataDomainNames(msg []byte, off, end int) ([]string, int, error) {
|
|
var (
|
|
servers []string
|
|
s string
|
|
err error
|
|
)
|
|
if end > len(msg) {
|
|
return nil, len(msg), &Error{err: "overflow unpacking domain names"}
|
|
}
|
|
for off < end {
|
|
s, off, err = UnpackDomainName(msg, off)
|
|
if err != nil {
|
|
return servers, len(msg), err
|
|
}
|
|
servers = append(servers, s)
|
|
}
|
|
return servers, off, nil
|
|
}
|
|
|
|
func packDataDomainNames(names []string, msg []byte, off int, compression compressionMap, compress bool) (int, error) {
|
|
var err error
|
|
for _, name := range names {
|
|
off, err = packDomainName(name, msg, off, compression, compress)
|
|
if err != nil {
|
|
return len(msg), err
|
|
}
|
|
}
|
|
return off, nil
|
|
}
|
|
|
|
func packDataApl(data []APLPrefix, msg []byte, off int) (int, error) {
|
|
var err error
|
|
for i := range data {
|
|
off, err = packDataAplPrefix(&data[i], msg, off)
|
|
if err != nil {
|
|
return len(msg), err
|
|
}
|
|
}
|
|
return off, nil
|
|
}
|
|
|
|
func packDataAplPrefix(p *APLPrefix, msg []byte, off int) (int, error) {
|
|
if len(p.Network.IP) != len(p.Network.Mask) {
|
|
return len(msg), &Error{err: "address and mask lengths don't match"}
|
|
}
|
|
|
|
var err error
|
|
prefix, _ := p.Network.Mask.Size()
|
|
addr := p.Network.IP.Mask(p.Network.Mask)[:(prefix+7)/8]
|
|
|
|
switch len(p.Network.IP) {
|
|
case net.IPv4len:
|
|
off, err = packUint16(1, msg, off)
|
|
case net.IPv6len:
|
|
off, err = packUint16(2, msg, off)
|
|
default:
|
|
err = &Error{err: "unrecognized address family"}
|
|
}
|
|
if err != nil {
|
|
return len(msg), err
|
|
}
|
|
|
|
off, err = packUint8(uint8(prefix), msg, off)
|
|
if err != nil {
|
|
return len(msg), err
|
|
}
|
|
|
|
var n uint8
|
|
if p.Negation {
|
|
n = 0x80
|
|
}
|
|
|
|
// trim trailing zero bytes as specified in RFC3123 Sections 4.1 and 4.2.
|
|
i := len(addr) - 1
|
|
for ; i >= 0 && addr[i] == 0; i-- {
|
|
}
|
|
addr = addr[:i+1]
|
|
|
|
adflen := uint8(len(addr)) & 0x7f
|
|
off, err = packUint8(n|adflen, msg, off)
|
|
if err != nil {
|
|
return len(msg), err
|
|
}
|
|
|
|
if off+len(addr) > len(msg) {
|
|
return len(msg), &Error{err: "overflow packing APL prefix"}
|
|
}
|
|
off += copy(msg[off:], addr)
|
|
|
|
return off, nil
|
|
}
|
|
|
|
func unpackDataApl(msg []byte, off int) ([]APLPrefix, int, error) {
|
|
var result []APLPrefix
|
|
for off < len(msg) {
|
|
prefix, end, err := unpackDataAplPrefix(msg, off)
|
|
if err != nil {
|
|
return nil, len(msg), err
|
|
}
|
|
off = end
|
|
result = append(result, prefix)
|
|
}
|
|
return result, off, nil
|
|
}
|
|
|
|
func unpackDataAplPrefix(msg []byte, off int) (APLPrefix, int, error) {
|
|
family, off, err := unpackUint16(msg, off)
|
|
if err != nil {
|
|
return APLPrefix{}, len(msg), &Error{err: "overflow unpacking APL prefix"}
|
|
}
|
|
prefix, off, err := unpackUint8(msg, off)
|
|
if err != nil {
|
|
return APLPrefix{}, len(msg), &Error{err: "overflow unpacking APL prefix"}
|
|
}
|
|
nlen, off, err := unpackUint8(msg, off)
|
|
if err != nil {
|
|
return APLPrefix{}, len(msg), &Error{err: "overflow unpacking APL prefix"}
|
|
}
|
|
|
|
var ip []byte
|
|
switch family {
|
|
case 1:
|
|
ip = make([]byte, net.IPv4len)
|
|
case 2:
|
|
ip = make([]byte, net.IPv6len)
|
|
default:
|
|
return APLPrefix{}, len(msg), &Error{err: "unrecognized APL address family"}
|
|
}
|
|
if int(prefix) > 8*len(ip) {
|
|
return APLPrefix{}, len(msg), &Error{err: "APL prefix too long"}
|
|
}
|
|
afdlen := int(nlen & 0x7f)
|
|
if afdlen > len(ip) {
|
|
return APLPrefix{}, len(msg), &Error{err: "APL length too long"}
|
|
}
|
|
if off+afdlen > len(msg) {
|
|
return APLPrefix{}, len(msg), &Error{err: "overflow unpacking APL address"}
|
|
}
|
|
off += copy(ip, msg[off:off+afdlen])
|
|
if afdlen > 0 {
|
|
last := ip[afdlen-1]
|
|
if last == 0 {
|
|
return APLPrefix{}, len(msg), &Error{err: "extra APL address bits"}
|
|
}
|
|
}
|
|
ipnet := net.IPNet{
|
|
IP: ip,
|
|
Mask: net.CIDRMask(int(prefix), 8*len(ip)),
|
|
}
|
|
network := ipnet.IP.Mask(ipnet.Mask)
|
|
if !network.Equal(ipnet.IP) {
|
|
return APLPrefix{}, len(msg), &Error{err: "invalid APL address length"}
|
|
}
|
|
|
|
return APLPrefix{
|
|
Negation: (nlen & 0x80) != 0,
|
|
Network: ipnet,
|
|
}, off, nil
|
|
}
|