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Cleanup and removals (#377) 

* Cleanup and removals

Gut rawmsg.go as most functions are not used. Reword some documentation.
Add more types to be checked for name compression.

* Yeah, we do use these

* Remove this function as well - only used one
This commit is contained in:
Miek Gieben 2016-06-13 19:44:38 +01:00 committed by GitHub
parent b51e305bc6
commit e6b37d00af
5 changed files with 64 additions and 122 deletions
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21
dns.go
View File

@ -3,17 +3,15 @@ package dns
import "strconv"
const (
year68 = 1 << 31 // For RFC1982 (Serial Arithmetic) calculations in 32 bits.
// DefaultMsgSize is the standard default for messages larger than 512 bytes.
DefaultMsgSize = 4096
// MinMsgSize is the minimal size of a DNS packet.
MinMsgSize = 512
// MaxMsgSize is the largest possible DNS packet.
MaxMsgSize = 65535
defaultTtl = 3600 // Default internal TTL.
year68 = 1 << 31 // For RFC1982 (Serial Arithmetic) calculations in 32 bits.
defaultTtl = 3600 // Default internal TTL.
DefaultMsgSize = 4096 // DefaultMsgSize is the standard default for messages larger than 512 bytes.
MinMsgSize = 512 // MinMsgSize is the minimal size of a DNS packet.
MaxMsgSize = 65535 // MaxMsgSize is the largest possible DNS packet.
)
// Error represents a DNS error
// Error represents a DNS error.
type Error struct{ err string }
func (e *Error) Error() string {
@ -30,6 +28,7 @@ type RR interface {
Header() *RR_Header
// String returns the text representation of the resource record.
String() string
// copy returns a copy of the RR
copy() RR
// len returns the length (in octets) of the uncompressed RR in wire format.
@ -44,10 +43,10 @@ type RR_Header struct {
Rrtype uint16
Class uint16
Ttl uint32
Rdlength uint16 // length of data after header
Rdlength uint16 // Length of data after header.
}
// Header returns itself. This is here to make RR_Header implement the RR interface.
// Header returns itself. This is here to make RR_Header implements the RR interface.
func (h *RR_Header) Header() *RR_Header { return h }
// Just to implement the RR interface.

110
msg.go
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@ -35,40 +35,27 @@ func init() {
const maxCompressionOffset = 2 << 13 // We have 14 bits for the compression pointer
var (
// ErrAlg indicates an error with the (DNSSEC) algorithm.
ErrAlg error = &Error{err: "bad algorithm"}
// ErrAuth indicates an error in the TSIG authentication.
ErrAuth error = &Error{err: "bad authentication"}
// ErrBuf indicates that the buffer used it too small for the message.
ErrBuf error = &Error{err: "buffer size too small"}
// ErrConnEmpty indicates a connection is being uses before it is initialized.
ErrConnEmpty error = &Error{err: "conn has no connection"}
// ErrExtendedRcode ...
ErrExtendedRcode error = &Error{err: "bad extended rcode"}
// ErrFqdn indicates that a domain name does not have a closing dot.
ErrFqdn error = &Error{err: "domain must be fully qualified"}
// ErrId indicates there is a mismatch with the message's ID.
ErrId error = &Error{err: "id mismatch"}
// ErrKeyAlg indicates that the algorithm in the key is not valid.
ErrKeyAlg error = &Error{err: "bad key algorithm"}
ErrKey error = &Error{err: "bad key"}
ErrKeySize error = &Error{err: "bad key size"}
ErrNoSig error = &Error{err: "no signature found"}
ErrPrivKey error = &Error{err: "bad private key"}
ErrRcode error = &Error{err: "bad rcode"}
ErrRdata error = &Error{err: "bad rdata"}
ErrRRset error = &Error{err: "bad rrset"}
ErrSecret error = &Error{err: "no secrets defined"}
ErrShortRead error = &Error{err: "short read"}
// ErrSig indicates that a signature can not be cryptographically validated.
ErrSig error = &Error{err: "bad signature"}
// ErrSOA indicates that no SOA RR was seen when doing zone transfers.
ErrSoa error = &Error{err: "no SOA"}
// ErrTime indicates a timing error in TSIG authentication.
ErrTime error = &Error{err: "bad time"}
// ErrTruncated indicates that we failed to unpack a truncated message.
// We unpacked as much as we had so Msg can still be used, if desired.
ErrTruncated error = &Error{err: "failed to unpack truncated message"}
ErrAlg error = &Error{err: "bad algorithm"} // ErrAlg indicates an error with the (DNSSEC) algorithm.
ErrAuth error = &Error{err: "bad authentication"} // ErrAuth indicates an error in the TSIG authentication.
ErrBuf error = &Error{err: "buffer size too small"} // ErrBuf indicates that the buffer used it too small for the message.
ErrConnEmpty error = &Error{err: "conn has no connection"} // ErrConnEmpty indicates a connection is being uses before it is initialized.
ErrExtendedRcode error = &Error{err: "bad extended rcode"} // ErrExtendedRcode ...
ErrFqdn error = &Error{err: "domain must be fully qualified"} // ErrFqdn indicates that a domain name does not have a closing dot.
ErrId error = &Error{err: "id mismatch"} // ErrId indicates there is a mismatch with the message's ID.
ErrKeyAlg error = &Error{err: "bad key algorithm"} // ErrKeyAlg indicates that the algorithm in the key is not valid.
ErrKey error = &Error{err: "bad key"}
ErrKeySize error = &Error{err: "bad key size"}
ErrNoSig error = &Error{err: "no signature found"}
ErrPrivKey error = &Error{err: "bad private key"}
ErrRcode error = &Error{err: "bad rcode"}
ErrRdata error = &Error{err: "bad rdata"}
ErrRRset error = &Error{err: "bad rrset"}
ErrSecret error = &Error{err: "no secrets defined"}
ErrShortRead error = &Error{err: "short read"}
ErrSig error = &Error{err: "bad signature"} // ErrSig indicates that a signature can not be cryptographically validated.
ErrSoa error = &Error{err: "no SOA"} // ErrSOA indicates that no SOA RR was seen when doing zone transfers.
ErrTime error = &Error{err: "bad time"} // ErrTime indicates a timing error in TSIG authentication.
ErrTruncated error = &Error{err: "failed to unpack truncated message"} // ErrTruncated indicates that we failed to unpack a truncated message. We unpacked as much as we had so Msg can still be used, if desired.
)
// Id, by default, returns a 16 bits random number to be used as a
@ -79,6 +66,13 @@ var (
// dns.Id = func() uint16 { return 3 }
var Id func() uint16 = id
// id returns a 16 bits random number to be used as a
// message id. The random provided should be good enough.
func id() uint16 {
id32 := rand.Uint32()
return uint16(id32)
}
// MsgHdr is a a manually-unpacked version of (id, bits).
type MsgHdr struct {
Id uint16
@ -97,7 +91,7 @@ type MsgHdr struct {
// Msg contains the layout of a DNS message.
type Msg struct {
MsgHdr
Compress bool `json:"-"` // If true, the message will be compressed when converted to wire format. This not part of the official DNS packet format.
Compress bool `json:"-"` // If true, the message will be compressed when converted to wire format.
Question []Question // Holds the RR(s) of the question section.
Answer []RR // Holds the RR(s) of the answer section.
Ns []RR // Holds the RR(s) of the authority section.
@ -131,7 +125,7 @@ var RcodeToString = map[int]string{
RcodeNameError: "NXDOMAIN",
RcodeNotImplemented: "NOTIMPL",
RcodeRefused: "REFUSED",
RcodeYXDomain: "YXDOMAIN", // From RFC 2136
RcodeYXDomain: "YXDOMAIN", // See RFC 2136
RcodeYXRrset: "YXRRSET",
RcodeNXRrset: "NXRRSET",
RcodeNotAuth: "NOTAUTH",
@ -147,12 +141,6 @@ var RcodeToString = map[int]string{
RcodeBadCookie: "BADCOOKIE",
}
// Rather than write the usual handful of routines to pack and
// unpack every message that can appear on the wire, we use
// reflection to write a generic pack/unpack for structs and then
// use it. Thus, if in the future we need to define new message
// structs, no new pack/unpack/printing code needs to be written.
// Domain names are a sequence of counted strings
// split at the dots. They end with a zero-length string.
@ -575,6 +563,7 @@ func PackRR(rr RR, msg []byte, off int, compression map[string]int, compress boo
if err != nil {
return len(msg), err
}
// TODO(miek): Not sure if this is needed? If removed we can remove rawmsg.go as well.
if rawSetRdlength(msg, off, off1) {
return off1, nil
}
@ -679,6 +668,7 @@ func (dns *Msg) Pack() (msg []byte, err error) {
// PackBuffer packs a Msg, using the given buffer buf. If buf is too small
// a new buffer is allocated.
func (dns *Msg) PackBuffer(buf []byte) (msg []byte, err error) {
// We use a similar function in tsig.go's stripTsig.
var (
dh Header
compression map[string]int
@ -1001,7 +991,7 @@ func compressionLenSearch(c map[string]int, s string) (int, bool) {
return 0, false
}
// TODO(miek): should add all types, because the all can be *used* for compression.
// TODO(miek): should add all types, because the all can be *used* for compression. Autogenerate from msg_generate and put in zmsg.go
func compressionLenHelperType(c map[string]int, r RR) {
switch x := r.(type) {
case *NS:
@ -1027,11 +1017,23 @@ func compressionLenHelperType(c map[string]int, r RR) {
compressionLenHelper(c, x.Md)
case *RT:
compressionLenHelper(c, x.Host)
case *RP:
compressionLenHelper(c, x.Mbox)
compressionLenHelper(c, x.Txt)
case *MINFO:
compressionLenHelper(c, x.Rmail)
compressionLenHelper(c, x.Email)
case *AFSDB:
compressionLenHelper(c, x.Hostname)
case *SRV:
compressionLenHelper(c, x.Target)
case *NAPTR:
compressionLenHelper(c, x.Replacement)
case *RRSIG:
compressionLenHelper(c, x.SignerName)
case *NSEC:
compressionLenHelper(c, x.NextDomain)
// HIP?
}
}
@ -1044,6 +1046,8 @@ func compressionLenSearchType(c map[string]int, r RR) (int, bool) {
return compressionLenSearch(c, x.Mx)
case *CNAME:
return compressionLenSearch(c, x.Target)
case *DNAME:
return compressionLenSearch(c, x.Target)
case *PTR:
return compressionLenSearch(c, x.Ptr)
case *SOA:
@ -1078,28 +1082,14 @@ func compressionLenSearchType(c map[string]int, r RR) (int, bool) {
return 0, false
}
// id returns a 16 bits random number to be used as a
// message id. The random provided should be good enough.
func id() uint16 {
id32 := rand.Uint32()
return uint16(id32)
}
// Copy returns a new RR which is a deep-copy of r.
func Copy(r RR) RR {
r1 := r.copy()
return r1
}
func Copy(r RR) RR { r1 := r.copy(); return r1 }
// Len returns the length (in octets) of the uncompressed RR in wire format.
func Len(r RR) int {
return r.len()
}
func Len(r RR) int { return r.len() }
// Copy returns a new *Msg which is a deep-copy of dns.
func (dns *Msg) Copy() *Msg {
return dns.CopyTo(new(Msg))
}
func (dns *Msg) Copy() *Msg { return dns.CopyTo(new(Msg)) }
// CopyTo copies the contents to the provided message using a deep-copy and returns the copy.
func (dns *Msg) CopyTo(r1 *Msg) *Msg {

3
nsecx.go
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@ -11,8 +11,7 @@ type saltWireFmt struct {
Salt string `dns:"size-hex"`
}
// HashName hashes a string (label) according to RFC 5155. It returns the hashed string in
// uppercase.
// HashName hashes a string (label) according to RFC 5155. It returns the hashed string in uppercase.
func HashName(label string, ha uint8, iter uint16, salt string) string {
saltwire := new(saltWireFmt)
saltwire.Salt = salt

48
rawmsg.go
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@ -2,54 +2,6 @@ package dns
import "encoding/binary"
// These raw* functions do not use reflection, they directly set the values
// in the buffer. There are faster than their reflection counterparts.
// RawSetId sets the message id in buf.
func rawSetId(msg []byte, i uint16) bool {
if len(msg) < 2 {
return false
}
binary.BigEndian.PutUint16(msg, i)
return true
}
// rawSetQuestionLen sets the length of the question section.
func rawSetQuestionLen(msg []byte, i uint16) bool {
if len(msg) < 6 {
return false
}
binary.BigEndian.PutUint16(msg[4:], i)
return true
}
// rawSetAnswerLen sets the length of the answer section.
func rawSetAnswerLen(msg []byte, i uint16) bool {
if len(msg) < 8 {
return false
}
binary.BigEndian.PutUint16(msg[6:], i)
return true
}
// rawSetsNsLen sets the length of the authority section.
func rawSetNsLen(msg []byte, i uint16) bool {
if len(msg) < 10 {
return false
}
binary.BigEndian.PutUint16(msg[8:], i)
return true
}
// rawSetExtraLen sets the length of the additional section.
func rawSetExtraLen(msg []byte, i uint16) bool {
if len(msg) < 12 {
return false
}
binary.BigEndian.PutUint16(msg[10:], i)
return true
}
// rawSetRdlength sets the rdlength in the header of
// the RR. The offset 'off' must be positioned at the
// start of the header of the RR, 'end' must be the

4
tsig.go
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@ -141,7 +141,9 @@ func TsigGenerate(m *Msg, secret, requestMAC string, timersOnly bool) ([]byte, s
return nil, "", err
}
mbuf = append(mbuf, tbuf...)
rawSetExtraLen(mbuf, uint16(len(m.Extra)+1))
// Update the ArCount directly in the buffer.
binary.BigEndian.PutUint16(mbuf[10:], uint16(len(m.Extra)+1))
return mbuf, t.MAC, nil
}