97 lines
2.2 KiB
Go
97 lines
2.2 KiB
Go
// EDNS0 OTP RR implementation. Define the OPT RR and some
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// convience functions to operate on it.
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package dns
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import (
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"strconv"
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)
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// EDNS0 option codes
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const (
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OptionCodeLLQ = 1 // Not used
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OptionCodeUL = 2 // Not used
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OptionCodeNSID = 3 // NSID, RFC5001
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// EDNS flag bits (put in Z section)
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_DO = 1 << 7 // dnssec ok
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)
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// An ENDS0 option rdata element.
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type Option struct {
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Code uint16
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Data string "hex"
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}
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/* EDNS extended RR.
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This is the EDNS0 Header
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Name string "domain-name"
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Opt uint16 // was type, but is always TypeOPT
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UDPSize uint16 // was class
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ExtendedRcode uint8 // was TTL
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Version uint8 // was TTL
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Z uint16 // was TTL (all flags should be put here)
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Rdlength uint16 // length of data after the header
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*/
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type RR_OPT struct {
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Hdr RR_Header
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Option []Option "OPT" // Tag is used in pack and unpack
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}
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func (rr *RR_OPT) Header() *RR_Header {
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return &rr.Hdr
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}
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func (rr *RR_OPT) String() string {
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s := ";; EDNS: version " + strconv.Itoa(int(rr.Version(0, false))) + "; "
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if rr.DoBit(false, false) {
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s += "flags: do; "
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} else {
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s += "flags: ; "
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}
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s += "udp: " + strconv.Itoa(int(rr.UDPSize(0, false))) + ";"
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for _, o := range rr.Option {
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switch o.Code {
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case OptionCodeNSID:
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s += " nsid: " + o.Data + ";"
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}
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}
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return s
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}
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// Set the version of edns, currently only 0 is there
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func (rr *RR_OPT) Version(v uint8, set bool) uint8 {
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return 0
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}
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// when set is true, set the size otherwise get it
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func (rr *RR_OPT) UDPSize(size uint16, set bool) uint16 {
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if set {
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rr.Hdr.Class = size
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}
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return rr.Hdr.Class
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}
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// when set is true, set the Do bit, otherwise get it
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func (rr *RR_OPT) DoBit(do, set bool) bool {
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// rr.TTL last 2 bytes, left most bit
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// See line 239 in msg.go for TTL encoding
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if set {
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leftbyte := byte(rr.Hdr.Ttl >> 24)
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leftbyte = leftbyte | _DO
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rr.Hdr.Ttl = uint32(leftbyte << 24)
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return true
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} else {
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// jaja?? TODO(MG)
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leftbyte := byte(rr.Hdr.Ttl >> 24)
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return leftbyte&_DO == 1
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}
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return true // dead code, bug in Go
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}
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// when set is true, set the nsid, otherwise get it
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func (rr *RR_OPT) Nsid(nsid string, set bool) string {
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// RR.Option[0] to be set
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return ""
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}
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