435c0d9fc8
This PR switches the Nomad repository from using govendor to Go modules for managing dependencies. Aspects of the Nomad workflow remain pretty much the same. The usual Makefile targets should continue to work as they always did. The API submodule simply defers to the parent Nomad version on the repository, keeping the semantics of API versioning that currently exists.
672 lines
20 KiB
Go
672 lines
20 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 (See RFC 5001)
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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 (See RFC 7871)
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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 (See RFC 7828)
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EDNS0PADDING = 0xc // EDNS0 padding (See RFC 7830)
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EDNS0LOCALSTART = 0xFDE9 // Beginning of range reserved for local/experimental use (See RFC 6891)
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EDNS0LOCALEND = 0xFFFE // End of range reserved for local/experimental use (See RFC 6891)
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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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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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case *EDNS0_PADDING:
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s += "\n; PADDING: " + 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(off int, compression map[string]struct{}) int {
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l := rr.Hdr.len(off, compression)
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for _, o := range rr.Option {
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l += 4 // Account for 2-byte option code and 2-byte option length.
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lo, _ := o.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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func (rr *OPT) parse(c *zlexer, origin string) *ParseError {
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panic("dns: internal error: parse should never be called on OPT")
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}
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func (r1 *OPT) isDuplicate(r2 RR) bool { return false }
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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) << 4
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}
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// SetExtendedRcode sets the EDNS extended RCODE field.
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//
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// If the RCODE is not an extended RCODE, will reset the extended RCODE field to 0.
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func (rr *OPT) SetExtendedRcode(v uint16) {
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rr.Hdr.Ttl = rr.Hdr.Ttl&0x00FFFFFF | uint32(v>>4)<<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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// copy returns a deep-copy of the option.
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copy() EDNS0
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}
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// EDNS0_NSID 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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// Option implements the EDNS0 interface.
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func (e *EDNS0_NSID) Option() uint16 { return EDNS0NSID } // Option returns the option code.
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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 e.Nsid }
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func (e *EDNS0_NSID) copy() EDNS0 { return &EDNS0_NSID{e.Code, 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. See RFC 7871. 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.SourceNetmask = 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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// This code will parse all the available bits when unpacking (up to optlen).
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// When packing it will apply SourceNetmask. If you need more advanced logic,
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// 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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}
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// Option implements the EDNS0 interface.
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func (e *EDNS0_SUBNET) Option() uint16 { return EDNS0SUBNET }
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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 0:
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// "dig" sets AddressFamily to 0 if SourceNetmask is also 0
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// We might don't need to complain either
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if e.SourceNetmask != 0 {
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return nil, errors.New("dns: bad address family")
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}
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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 0:
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// "dig" sets AddressFamily to 0 if SourceNetmask is also 0
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// It's okay to accept such a packet
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if e.SourceNetmask != 0 {
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return errors.New("dns: bad address family")
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}
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e.Address = net.IPv4(0, 0, 0, 0)
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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(net.IP, net.IPv4len)
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copy(addr, b[4:])
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e.Address = addr.To16()
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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(net.IP, net.IPv6len)
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copy(addr, b[4:])
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e.Address = addr
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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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func (e *EDNS0_SUBNET) copy() EDNS0 {
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return &EDNS0_SUBNET{
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e.Code,
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e.Family,
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e.SourceNetmask,
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e.SourceScope,
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e.Address,
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}
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}
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// The EDNS0_COOKIE option is used to add a DNS Cookie to a message.
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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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// Option implements the EDNS0 interface.
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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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func (e *EDNS0_COOKIE) copy() EDNS0 { return &EDNS0_COOKIE{e.Code, 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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// https://tools.ietf.org/html/draft-sekar-dns-ul-02
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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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KeyLease uint32
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}
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// Option implements the EDNS0 interface.
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func (e *EDNS0_UL) Option() uint16 { return EDNS0UL }
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func (e *EDNS0_UL) String() string { return fmt.Sprintf("%d %d", e.Lease, e.KeyLease) }
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func (e *EDNS0_UL) copy() EDNS0 { return &EDNS0_UL{e.Code, e.Lease, e.KeyLease} }
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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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var b []byte
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if e.KeyLease == 0 {
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b = make([]byte, 4)
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} else {
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b = make([]byte, 8)
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binary.BigEndian.PutUint32(b[4:], e.KeyLease)
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}
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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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switch len(b) {
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case 4:
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e.KeyLease = 0
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case 8:
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e.KeyLease = binary.BigEndian.Uint32(b[4:])
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default:
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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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// Option implements the EDNS0 interface.
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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(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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func (e *EDNS0_LLQ) copy() EDNS0 {
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return &EDNS0_LLQ{e.Code, e.Version, e.Opcode, e.Error, e.Id, e.LeaseLife}
|
|
}
|
|
|
|
// EDNS0_DUA implements the EDNS0 "DNSSEC Algorithm Understood" option. See RFC 6975.
|
|
type EDNS0_DAU struct {
|
|
Code uint16 // Always EDNS0DAU
|
|
AlgCode []uint8
|
|
}
|
|
|
|
// Option implements the EDNS0 interface.
|
|
func (e *EDNS0_DAU) Option() uint16 { return EDNS0DAU }
|
|
func (e *EDNS0_DAU) pack() ([]byte, error) { return e.AlgCode, nil }
|
|
func (e *EDNS0_DAU) unpack(b []byte) error { e.AlgCode = b; return nil }
|
|
|
|
func (e *EDNS0_DAU) String() string {
|
|
s := ""
|
|
for _, alg := range e.AlgCode {
|
|
if a, ok := AlgorithmToString[alg]; ok {
|
|
s += " " + a
|
|
} else {
|
|
s += " " + strconv.Itoa(int(alg))
|
|
}
|
|
}
|
|
return s
|
|
}
|
|
func (e *EDNS0_DAU) copy() EDNS0 { return &EDNS0_DAU{e.Code, e.AlgCode} }
|
|
|
|
// EDNS0_DHU implements the EDNS0 "DS Hash Understood" option. See RFC 6975.
|
|
type EDNS0_DHU struct {
|
|
Code uint16 // Always EDNS0DHU
|
|
AlgCode []uint8
|
|
}
|
|
|
|
// Option implements the EDNS0 interface.
|
|
func (e *EDNS0_DHU) Option() uint16 { return EDNS0DHU }
|
|
func (e *EDNS0_DHU) pack() ([]byte, error) { return e.AlgCode, nil }
|
|
func (e *EDNS0_DHU) unpack(b []byte) error { e.AlgCode = b; return nil }
|
|
|
|
func (e *EDNS0_DHU) String() string {
|
|
s := ""
|
|
for _, alg := range e.AlgCode {
|
|
if a, ok := HashToString[alg]; ok {
|
|
s += " " + a
|
|
} else {
|
|
s += " " + strconv.Itoa(int(alg))
|
|
}
|
|
}
|
|
return s
|
|
}
|
|
func (e *EDNS0_DHU) copy() EDNS0 { return &EDNS0_DHU{e.Code, e.AlgCode} }
|
|
|
|
// EDNS0_N3U implements the EDNS0 "NSEC3 Hash Understood" option. See RFC 6975.
|
|
type EDNS0_N3U struct {
|
|
Code uint16 // Always EDNS0N3U
|
|
AlgCode []uint8
|
|
}
|
|
|
|
// Option implements the EDNS0 interface.
|
|
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 _, alg := range e.AlgCode {
|
|
if a, ok := HashToString[alg]; ok {
|
|
s += " " + a
|
|
} else {
|
|
s += " " + strconv.Itoa(int(alg))
|
|
}
|
|
}
|
|
return s
|
|
}
|
|
func (e *EDNS0_N3U) copy() EDNS0 { return &EDNS0_N3U{e.Code, e.AlgCode} }
|
|
|
|
// EDNS0_EXPIRE implementes the EDNS0 option as described in RFC 7314.
|
|
type EDNS0_EXPIRE struct {
|
|
Code uint16 // Always EDNS0EXPIRE
|
|
Expire uint32
|
|
}
|
|
|
|
// Option implements the EDNS0 interface.
|
|
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) copy() EDNS0 { return &EDNS0_EXPIRE{e.Code, e.Expire} }
|
|
|
|
func (e *EDNS0_EXPIRE) pack() ([]byte, error) {
|
|
b := make([]byte, 4)
|
|
binary.BigEndian.PutUint32(b, 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
|
|
}
|
|
|
|
// Option implements the EDNS0 interface.
|
|
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) copy() EDNS0 {
|
|
b := make([]byte, len(e.Data))
|
|
copy(b, e.Data)
|
|
return &EDNS0_LOCAL{e.Code, b}
|
|
}
|
|
|
|
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
|
|
}
|
|
|
|
// EDNS0_TCP_KEEPALIVE is an EDNS0 option that instructs the server to keep
|
|
// the TCP connection alive. See RFC 7828.
|
|
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.
|
|
}
|
|
|
|
// Option implements the EDNS0 interface.
|
|
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
|
|
}
|
|
func (e *EDNS0_TCP_KEEPALIVE) copy() EDNS0 { return &EDNS0_TCP_KEEPALIVE{e.Code, e.Length, e.Timeout} }
|
|
|
|
// EDNS0_PADDING option is used to add padding to a request/response. The default
|
|
// value of padding SHOULD be 0x0 but other values MAY be used, for instance if
|
|
// compression is applied before encryption which may break signatures.
|
|
type EDNS0_PADDING struct {
|
|
Padding []byte
|
|
}
|
|
|
|
// Option implements the EDNS0 interface.
|
|
func (e *EDNS0_PADDING) Option() uint16 { return EDNS0PADDING }
|
|
func (e *EDNS0_PADDING) pack() ([]byte, error) { return e.Padding, nil }
|
|
func (e *EDNS0_PADDING) unpack(b []byte) error { e.Padding = b; return nil }
|
|
func (e *EDNS0_PADDING) String() string { return fmt.Sprintf("%0X", e.Padding) }
|
|
func (e *EDNS0_PADDING) copy() EDNS0 {
|
|
b := make([]byte, len(e.Padding))
|
|
copy(b, e.Padding)
|
|
return &EDNS0_PADDING{b}
|
|
}
|