a685e3fc98
Vndr has a simpler configuration and allows pointing to forked packages. Additionally other docker projects are now using vndr making vendoring in distribution more consistent. Updates letsencrypt to use fork. No longer uses sub-vendored packages. Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
598 lines
17 KiB
Go
598 lines
17 KiB
Go
package dns
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import (
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"encoding/binary"
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"encoding/hex"
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"errors"
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"fmt"
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"net"
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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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EDNS0LLQ = 0x1 // long lived queries: http://tools.ietf.org/html/draft-sekar-dns-llq-01
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EDNS0UL = 0x2 // update lease draft: http://files.dns-sd.org/draft-sekar-dns-ul.txt
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EDNS0NSID = 0x3 // nsid (RFC5001)
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EDNS0DAU = 0x5 // DNSSEC Algorithm Understood
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EDNS0DHU = 0x6 // DS Hash Understood
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EDNS0N3U = 0x7 // NSEC3 Hash Understood
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EDNS0SUBNET = 0x8 // client-subnet (RFC6891)
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EDNS0EXPIRE = 0x9 // EDNS0 expire
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EDNS0COOKIE = 0xa // EDNS0 Cookie
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EDNS0TCPKEEPALIVE = 0xb // EDNS0 tcp keep alive (RFC7828)
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EDNS0SUBNETDRAFT = 0x50fa // Don't use! Use EDNS0SUBNET
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EDNS0LOCALSTART = 0xFDE9 // Beginning of range reserved for local/experimental use (RFC6891)
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EDNS0LOCALEND = 0xFFFE // End of range reserved for local/experimental use (RFC6891)
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_DO = 1 << 15 // dnssec ok
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)
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// OPT is the EDNS0 RR appended to messages to convey extra (meta) information.
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// See RFC 6891.
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type OPT struct {
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Hdr RR_Header
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Option []EDNS0 `dns:"opt"`
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}
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func (rr *OPT) String() string {
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s := "\n;; OPT PSEUDOSECTION:\n; EDNS: version " + strconv.Itoa(int(rr.Version())) + "; "
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if rr.Do() {
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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()))
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for _, o := range rr.Option {
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switch o.(type) {
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case *EDNS0_NSID:
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s += "\n; NSID: " + o.String()
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h, e := o.pack()
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var r string
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if e == nil {
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for _, c := range h {
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r += "(" + string(c) + ")"
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}
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s += " " + r
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}
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case *EDNS0_SUBNET:
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s += "\n; SUBNET: " + o.String()
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if o.(*EDNS0_SUBNET).DraftOption {
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s += " (draft)"
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}
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case *EDNS0_COOKIE:
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s += "\n; COOKIE: " + o.String()
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case *EDNS0_UL:
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s += "\n; UPDATE LEASE: " + o.String()
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case *EDNS0_LLQ:
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s += "\n; LONG LIVED QUERIES: " + o.String()
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case *EDNS0_DAU:
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s += "\n; DNSSEC ALGORITHM UNDERSTOOD: " + o.String()
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case *EDNS0_DHU:
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s += "\n; DS HASH UNDERSTOOD: " + o.String()
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case *EDNS0_N3U:
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s += "\n; NSEC3 HASH UNDERSTOOD: " + o.String()
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case *EDNS0_LOCAL:
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s += "\n; LOCAL OPT: " + o.String()
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}
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}
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return s
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}
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func (rr *OPT) len() int {
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l := rr.Hdr.len()
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for i := 0; i < len(rr.Option); i++ {
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l += 4 // Account for 2-byte option code and 2-byte option length.
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lo, _ := rr.Option[i].pack()
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l += len(lo)
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}
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return l
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}
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// return the old value -> delete SetVersion?
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// Version returns the EDNS version used. Only zero is defined.
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func (rr *OPT) Version() uint8 {
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return uint8((rr.Hdr.Ttl & 0x00FF0000) >> 16)
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}
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// SetVersion sets the version of EDNS. This is usually zero.
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func (rr *OPT) SetVersion(v uint8) {
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rr.Hdr.Ttl = rr.Hdr.Ttl&0xFF00FFFF | (uint32(v) << 16)
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}
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// ExtendedRcode returns the EDNS extended RCODE field (the upper 8 bits of the TTL).
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func (rr *OPT) ExtendedRcode() int {
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return int((rr.Hdr.Ttl&0xFF000000)>>24) + 15
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}
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// SetExtendedRcode sets the EDNS extended RCODE field.
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func (rr *OPT) SetExtendedRcode(v uint8) {
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if v < RcodeBadVers { // Smaller than 16.. Use the 4 bits you have!
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return
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}
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rr.Hdr.Ttl = rr.Hdr.Ttl&0x00FFFFFF | (uint32(v-15) << 24)
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}
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// UDPSize returns the UDP buffer size.
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func (rr *OPT) UDPSize() uint16 {
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return rr.Hdr.Class
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}
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// SetUDPSize sets the UDP buffer size.
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func (rr *OPT) SetUDPSize(size uint16) {
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rr.Hdr.Class = size
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}
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// Do returns the value of the DO (DNSSEC OK) bit.
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func (rr *OPT) Do() bool {
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return rr.Hdr.Ttl&_DO == _DO
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}
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// SetDo sets the DO (DNSSEC OK) bit.
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// If we pass an argument, set the DO bit to that value.
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// It is possible to pass 2 or more arguments. Any arguments after the 1st is silently ignored.
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func (rr *OPT) SetDo(do ...bool) {
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if len(do) == 1 {
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if do[0] {
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rr.Hdr.Ttl |= _DO
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} else {
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rr.Hdr.Ttl &^= _DO
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}
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} else {
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rr.Hdr.Ttl |= _DO
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}
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}
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// EDNS0 defines an EDNS0 Option. An OPT RR can have multiple options appended to it.
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type EDNS0 interface {
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// Option returns the option code for the option.
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Option() uint16
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// pack returns the bytes of the option data.
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pack() ([]byte, error)
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// unpack sets the data as found in the buffer. Is also sets
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// the length of the slice as the length of the option data.
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unpack([]byte) error
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// String returns the string representation of the option.
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String() string
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}
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// The nsid EDNS0 option is used to retrieve a nameserver
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// identifier. When sending a request Nsid must be set to the empty string
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// The identifier is an opaque string encoded as hex.
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// Basic use pattern for creating an nsid option:
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//
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// o := new(dns.OPT)
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// o.Hdr.Name = "."
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// o.Hdr.Rrtype = dns.TypeOPT
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// e := new(dns.EDNS0_NSID)
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// e.Code = dns.EDNS0NSID
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// e.Nsid = "AA"
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// o.Option = append(o.Option, e)
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type EDNS0_NSID struct {
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Code uint16 // Always EDNS0NSID
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Nsid string // This string needs to be hex encoded
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}
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func (e *EDNS0_NSID) pack() ([]byte, error) {
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h, err := hex.DecodeString(e.Nsid)
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if err != nil {
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return nil, err
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}
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return h, nil
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}
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func (e *EDNS0_NSID) Option() uint16 { return EDNS0NSID }
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func (e *EDNS0_NSID) unpack(b []byte) error { e.Nsid = hex.EncodeToString(b); return nil }
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func (e *EDNS0_NSID) String() string { return string(e.Nsid) }
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// EDNS0_SUBNET is the subnet option that is used to give the remote nameserver
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// an idea of where the client lives. It can then give back a different
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// answer depending on the location or network topology.
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// Basic use pattern for creating an subnet option:
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//
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// o := new(dns.OPT)
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// o.Hdr.Name = "."
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// o.Hdr.Rrtype = dns.TypeOPT
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// e := new(dns.EDNS0_SUBNET)
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// e.Code = dns.EDNS0SUBNET
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// e.Family = 1 // 1 for IPv4 source address, 2 for IPv6
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// e.NetMask = 32 // 32 for IPV4, 128 for IPv6
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// e.SourceScope = 0
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// e.Address = net.ParseIP("127.0.0.1").To4() // for IPv4
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// // e.Address = net.ParseIP("2001:7b8:32a::2") // for IPV6
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// o.Option = append(o.Option, e)
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//
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// Note: the spec (draft-ietf-dnsop-edns-client-subnet-00) has some insane logic
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// for which netmask applies to the address. This code will parse all the
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// available bits when unpacking (up to optlen). When packing it will apply
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// SourceNetmask. If you need more advanced logic, patches welcome and good luck.
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type EDNS0_SUBNET struct {
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Code uint16 // Always EDNS0SUBNET
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Family uint16 // 1 for IP, 2 for IP6
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SourceNetmask uint8
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SourceScope uint8
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Address net.IP
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DraftOption bool // Set to true if using the old (0x50fa) option code
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}
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func (e *EDNS0_SUBNET) Option() uint16 {
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if e.DraftOption {
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return EDNS0SUBNETDRAFT
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}
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return EDNS0SUBNET
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}
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func (e *EDNS0_SUBNET) pack() ([]byte, error) {
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b := make([]byte, 4)
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binary.BigEndian.PutUint16(b[0:], e.Family)
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b[2] = e.SourceNetmask
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b[3] = e.SourceScope
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switch e.Family {
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case 1:
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if e.SourceNetmask > net.IPv4len*8 {
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return nil, errors.New("dns: bad netmask")
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}
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if len(e.Address.To4()) != net.IPv4len {
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return nil, errors.New("dns: bad address")
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}
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ip := e.Address.To4().Mask(net.CIDRMask(int(e.SourceNetmask), net.IPv4len*8))
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needLength := (e.SourceNetmask + 8 - 1) / 8 // division rounding up
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b = append(b, ip[:needLength]...)
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case 2:
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if e.SourceNetmask > net.IPv6len*8 {
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return nil, errors.New("dns: bad netmask")
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}
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if len(e.Address) != net.IPv6len {
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return nil, errors.New("dns: bad address")
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}
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ip := e.Address.Mask(net.CIDRMask(int(e.SourceNetmask), net.IPv6len*8))
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needLength := (e.SourceNetmask + 8 - 1) / 8 // division rounding up
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b = append(b, ip[:needLength]...)
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default:
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return nil, errors.New("dns: bad address family")
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}
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return b, nil
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}
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func (e *EDNS0_SUBNET) unpack(b []byte) error {
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if len(b) < 4 {
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return ErrBuf
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}
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e.Family = binary.BigEndian.Uint16(b)
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e.SourceNetmask = b[2]
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e.SourceScope = b[3]
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switch e.Family {
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case 1:
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if e.SourceNetmask > net.IPv4len*8 || e.SourceScope > net.IPv4len*8 {
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return errors.New("dns: bad netmask")
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}
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addr := make([]byte, net.IPv4len)
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for i := 0; i < net.IPv4len && 4+i < len(b); i++ {
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addr[i] = b[4+i]
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}
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e.Address = net.IPv4(addr[0], addr[1], addr[2], addr[3])
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case 2:
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if e.SourceNetmask > net.IPv6len*8 || e.SourceScope > net.IPv6len*8 {
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return errors.New("dns: bad netmask")
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}
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addr := make([]byte, net.IPv6len)
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for i := 0; i < net.IPv6len && 4+i < len(b); i++ {
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addr[i] = b[4+i]
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}
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e.Address = net.IP{addr[0], addr[1], addr[2], addr[3], addr[4],
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addr[5], addr[6], addr[7], addr[8], addr[9], addr[10],
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addr[11], addr[12], addr[13], addr[14], addr[15]}
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default:
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return errors.New("dns: bad address family")
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}
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return nil
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}
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func (e *EDNS0_SUBNET) String() (s string) {
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if e.Address == nil {
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s = "<nil>"
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} else if e.Address.To4() != nil {
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s = e.Address.String()
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} else {
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s = "[" + e.Address.String() + "]"
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}
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s += "/" + strconv.Itoa(int(e.SourceNetmask)) + "/" + strconv.Itoa(int(e.SourceScope))
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return
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}
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// The Cookie EDNS0 option
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//
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// o := new(dns.OPT)
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// o.Hdr.Name = "."
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// o.Hdr.Rrtype = dns.TypeOPT
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// e := new(dns.EDNS0_COOKIE)
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// e.Code = dns.EDNS0COOKIE
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// e.Cookie = "24a5ac.."
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// o.Option = append(o.Option, e)
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//
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// The Cookie field consists out of a client cookie (RFC 7873 Section 4), that is
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// always 8 bytes. It may then optionally be followed by the server cookie. The server
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// cookie is of variable length, 8 to a maximum of 32 bytes. In other words:
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//
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// cCookie := o.Cookie[:16]
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// sCookie := o.Cookie[16:]
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//
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// There is no guarantee that the Cookie string has a specific length.
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type EDNS0_COOKIE struct {
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Code uint16 // Always EDNS0COOKIE
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Cookie string // Hex-encoded cookie data
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}
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func (e *EDNS0_COOKIE) pack() ([]byte, error) {
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h, err := hex.DecodeString(e.Cookie)
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if err != nil {
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return nil, err
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}
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return h, nil
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}
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func (e *EDNS0_COOKIE) Option() uint16 { return EDNS0COOKIE }
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func (e *EDNS0_COOKIE) unpack(b []byte) error { e.Cookie = hex.EncodeToString(b); return nil }
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func (e *EDNS0_COOKIE) String() string { return e.Cookie }
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// The EDNS0_UL (Update Lease) (draft RFC) option is used to tell the server to set
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// an expiration on an update RR. This is helpful for clients that cannot clean
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// up after themselves. This is a draft RFC and more information can be found at
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// http://files.dns-sd.org/draft-sekar-dns-ul.txt
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//
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// o := new(dns.OPT)
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// o.Hdr.Name = "."
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// o.Hdr.Rrtype = dns.TypeOPT
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// e := new(dns.EDNS0_UL)
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// e.Code = dns.EDNS0UL
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// e.Lease = 120 // in seconds
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// o.Option = append(o.Option, e)
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type EDNS0_UL struct {
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Code uint16 // Always EDNS0UL
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Lease uint32
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}
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func (e *EDNS0_UL) Option() uint16 { return EDNS0UL }
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func (e *EDNS0_UL) String() string { return strconv.FormatUint(uint64(e.Lease), 10) }
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// Copied: http://golang.org/src/pkg/net/dnsmsg.go
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func (e *EDNS0_UL) pack() ([]byte, error) {
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b := make([]byte, 4)
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binary.BigEndian.PutUint32(b, e.Lease)
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return b, nil
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}
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func (e *EDNS0_UL) unpack(b []byte) error {
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if len(b) < 4 {
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return ErrBuf
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}
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e.Lease = binary.BigEndian.Uint32(b)
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return nil
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}
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// EDNS0_LLQ stands for Long Lived Queries: http://tools.ietf.org/html/draft-sekar-dns-llq-01
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// Implemented for completeness, as the EDNS0 type code is assigned.
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type EDNS0_LLQ struct {
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Code uint16 // Always EDNS0LLQ
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Version uint16
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Opcode uint16
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Error uint16
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Id uint64
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LeaseLife uint32
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}
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func (e *EDNS0_LLQ) Option() uint16 { return EDNS0LLQ }
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func (e *EDNS0_LLQ) pack() ([]byte, error) {
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b := make([]byte, 18)
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binary.BigEndian.PutUint16(b[0:], e.Version)
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binary.BigEndian.PutUint16(b[2:], e.Opcode)
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binary.BigEndian.PutUint16(b[4:], e.Error)
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binary.BigEndian.PutUint64(b[6:], e.Id)
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binary.BigEndian.PutUint32(b[14:], e.LeaseLife)
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return b, nil
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}
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func (e *EDNS0_LLQ) unpack(b []byte) error {
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if len(b) < 18 {
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return ErrBuf
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}
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e.Version = binary.BigEndian.Uint16(b[0:])
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e.Opcode = binary.BigEndian.Uint16(b[2:])
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e.Error = binary.BigEndian.Uint16(b[4:])
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e.Id = binary.BigEndian.Uint64(b[6:])
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e.LeaseLife = binary.BigEndian.Uint32(b[14:])
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return nil
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}
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func (e *EDNS0_LLQ) String() string {
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s := strconv.FormatUint(uint64(e.Version), 10) + " " + strconv.FormatUint(uint64(e.Opcode), 10) +
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" " + strconv.FormatUint(uint64(e.Error), 10) + " " + strconv.FormatUint(uint64(e.Id), 10) +
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" " + strconv.FormatUint(uint64(e.LeaseLife), 10)
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return s
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}
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type EDNS0_DAU struct {
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Code uint16 // Always EDNS0DAU
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AlgCode []uint8
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}
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func (e *EDNS0_DAU) Option() uint16 { return EDNS0DAU }
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func (e *EDNS0_DAU) pack() ([]byte, error) { return e.AlgCode, nil }
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func (e *EDNS0_DAU) unpack(b []byte) error { e.AlgCode = b; return nil }
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func (e *EDNS0_DAU) String() string {
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s := ""
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for i := 0; i < len(e.AlgCode); i++ {
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if a, ok := AlgorithmToString[e.AlgCode[i]]; ok {
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s += " " + a
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} else {
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s += " " + strconv.Itoa(int(e.AlgCode[i]))
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}
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}
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return s
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}
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type EDNS0_DHU struct {
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Code uint16 // Always EDNS0DHU
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AlgCode []uint8
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}
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func (e *EDNS0_DHU) Option() uint16 { return EDNS0DHU }
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func (e *EDNS0_DHU) pack() ([]byte, error) { return e.AlgCode, nil }
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func (e *EDNS0_DHU) unpack(b []byte) error { e.AlgCode = b; return nil }
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func (e *EDNS0_DHU) String() string {
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s := ""
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for i := 0; i < len(e.AlgCode); i++ {
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if a, ok := HashToString[e.AlgCode[i]]; ok {
|
|
s += " " + a
|
|
} else {
|
|
s += " " + strconv.Itoa(int(e.AlgCode[i]))
|
|
}
|
|
}
|
|
return s
|
|
}
|
|
|
|
type EDNS0_N3U struct {
|
|
Code uint16 // Always EDNS0N3U
|
|
AlgCode []uint8
|
|
}
|
|
|
|
func (e *EDNS0_N3U) Option() uint16 { return EDNS0N3U }
|
|
func (e *EDNS0_N3U) pack() ([]byte, error) { return e.AlgCode, nil }
|
|
func (e *EDNS0_N3U) unpack(b []byte) error { e.AlgCode = b; return nil }
|
|
|
|
func (e *EDNS0_N3U) String() string {
|
|
// Re-use the hash map
|
|
s := ""
|
|
for i := 0; i < len(e.AlgCode); i++ {
|
|
if a, ok := HashToString[e.AlgCode[i]]; ok {
|
|
s += " " + a
|
|
} else {
|
|
s += " " + strconv.Itoa(int(e.AlgCode[i]))
|
|
}
|
|
}
|
|
return s
|
|
}
|
|
|
|
type EDNS0_EXPIRE struct {
|
|
Code uint16 // Always EDNS0EXPIRE
|
|
Expire uint32
|
|
}
|
|
|
|
func (e *EDNS0_EXPIRE) Option() uint16 { return EDNS0EXPIRE }
|
|
func (e *EDNS0_EXPIRE) String() string { return strconv.FormatUint(uint64(e.Expire), 10) }
|
|
|
|
func (e *EDNS0_EXPIRE) pack() ([]byte, error) {
|
|
b := make([]byte, 4)
|
|
b[0] = byte(e.Expire >> 24)
|
|
b[1] = byte(e.Expire >> 16)
|
|
b[2] = byte(e.Expire >> 8)
|
|
b[3] = byte(e.Expire)
|
|
return b, nil
|
|
}
|
|
|
|
func (e *EDNS0_EXPIRE) unpack(b []byte) error {
|
|
if len(b) < 4 {
|
|
return ErrBuf
|
|
}
|
|
e.Expire = binary.BigEndian.Uint32(b)
|
|
return nil
|
|
}
|
|
|
|
// The EDNS0_LOCAL option is used for local/experimental purposes. The option
|
|
// code is recommended to be within the range [EDNS0LOCALSTART, EDNS0LOCALEND]
|
|
// (RFC6891), although any unassigned code can actually be used. The content of
|
|
// the option is made available in Data, unaltered.
|
|
// Basic use pattern for creating a local option:
|
|
//
|
|
// o := new(dns.OPT)
|
|
// o.Hdr.Name = "."
|
|
// o.Hdr.Rrtype = dns.TypeOPT
|
|
// e := new(dns.EDNS0_LOCAL)
|
|
// e.Code = dns.EDNS0LOCALSTART
|
|
// e.Data = []byte{72, 82, 74}
|
|
// o.Option = append(o.Option, e)
|
|
type EDNS0_LOCAL struct {
|
|
Code uint16
|
|
Data []byte
|
|
}
|
|
|
|
func (e *EDNS0_LOCAL) Option() uint16 { return e.Code }
|
|
func (e *EDNS0_LOCAL) String() string {
|
|
return strconv.FormatInt(int64(e.Code), 10) + ":0x" + hex.EncodeToString(e.Data)
|
|
}
|
|
|
|
func (e *EDNS0_LOCAL) pack() ([]byte, error) {
|
|
b := make([]byte, len(e.Data))
|
|
copied := copy(b, e.Data)
|
|
if copied != len(e.Data) {
|
|
return nil, ErrBuf
|
|
}
|
|
return b, nil
|
|
}
|
|
|
|
func (e *EDNS0_LOCAL) unpack(b []byte) error {
|
|
e.Data = make([]byte, len(b))
|
|
copied := copy(e.Data, b)
|
|
if copied != len(b) {
|
|
return ErrBuf
|
|
}
|
|
return nil
|
|
}
|
|
|
|
type EDNS0_TCP_KEEPALIVE struct {
|
|
Code uint16 // Always EDNSTCPKEEPALIVE
|
|
Length uint16 // the value 0 if the TIMEOUT is omitted, the value 2 if it is present;
|
|
Timeout uint16 // an idle timeout value for the TCP connection, specified in units of 100 milliseconds, encoded in network byte order.
|
|
}
|
|
|
|
func (e *EDNS0_TCP_KEEPALIVE) Option() uint16 {
|
|
return EDNS0TCPKEEPALIVE
|
|
}
|
|
|
|
func (e *EDNS0_TCP_KEEPALIVE) pack() ([]byte, error) {
|
|
if e.Timeout != 0 && e.Length != 2 {
|
|
return nil, errors.New("dns: timeout specified but length is not 2")
|
|
}
|
|
if e.Timeout == 0 && e.Length != 0 {
|
|
return nil, errors.New("dns: timeout not specified but length is not 0")
|
|
}
|
|
b := make([]byte, 4+e.Length)
|
|
binary.BigEndian.PutUint16(b[0:], e.Code)
|
|
binary.BigEndian.PutUint16(b[2:], e.Length)
|
|
if e.Length == 2 {
|
|
binary.BigEndian.PutUint16(b[4:], e.Timeout)
|
|
}
|
|
return b, nil
|
|
}
|
|
|
|
func (e *EDNS0_TCP_KEEPALIVE) unpack(b []byte) error {
|
|
if len(b) < 4 {
|
|
return ErrBuf
|
|
}
|
|
e.Length = binary.BigEndian.Uint16(b[2:4])
|
|
if e.Length != 0 && e.Length != 2 {
|
|
return errors.New("dns: length mismatch, want 0/2 but got " + strconv.FormatUint(uint64(e.Length), 10))
|
|
}
|
|
if e.Length == 2 {
|
|
if len(b) < 6 {
|
|
return ErrBuf
|
|
}
|
|
e.Timeout = binary.BigEndian.Uint16(b[4:6])
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (e *EDNS0_TCP_KEEPALIVE) String() (s string) {
|
|
s = "use tcp keep-alive"
|
|
if e.Length == 0 {
|
|
s += ", timeout omitted"
|
|
} else {
|
|
s += fmt.Sprintf(", timeout %dms", e.Timeout*100)
|
|
}
|
|
return
|
|
}
|