distribution/vendor/github.com/miekg/dns/scan.go
Derek McGowan a685e3fc98
Replace godep with vndr
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)
2016-11-23 15:07:06 -08:00

981 lines
23 KiB
Go

package dns
import (
"io"
"log"
"os"
"strconv"
"strings"
)
type debugging bool
const debug debugging = false
func (d debugging) Printf(format string, args ...interface{}) {
if d {
log.Printf(format, args...)
}
}
const maxTok = 2048 // Largest token we can return.
const maxUint16 = 1<<16 - 1
// Tokinize a RFC 1035 zone file. The tokenizer will normalize it:
// * Add ownernames if they are left blank;
// * Suppress sequences of spaces;
// * Make each RR fit on one line (_NEWLINE is send as last)
// * Handle comments: ;
// * Handle braces - anywhere.
const (
// Zonefile
zEOF = iota
zString
zBlank
zQuote
zNewline
zRrtpe
zOwner
zClass
zDirOrigin // $ORIGIN
zDirTtl // $TTL
zDirInclude // $INCLUDE
zDirGenerate // $GENERATE
// Privatekey file
zValue
zKey
zExpectOwnerDir // Ownername
zExpectOwnerBl // Whitespace after the ownername
zExpectAny // Expect rrtype, ttl or class
zExpectAnyNoClass // Expect rrtype or ttl
zExpectAnyNoClassBl // The whitespace after _EXPECT_ANY_NOCLASS
zExpectAnyNoTtl // Expect rrtype or class
zExpectAnyNoTtlBl // Whitespace after _EXPECT_ANY_NOTTL
zExpectRrtype // Expect rrtype
zExpectRrtypeBl // Whitespace BEFORE rrtype
zExpectRdata // The first element of the rdata
zExpectDirTtlBl // Space after directive $TTL
zExpectDirTtl // Directive $TTL
zExpectDirOriginBl // Space after directive $ORIGIN
zExpectDirOrigin // Directive $ORIGIN
zExpectDirIncludeBl // Space after directive $INCLUDE
zExpectDirInclude // Directive $INCLUDE
zExpectDirGenerate // Directive $GENERATE
zExpectDirGenerateBl // Space after directive $GENERATE
)
// ParseError is a parsing error. It contains the parse error and the location in the io.Reader
// where the error occurred.
type ParseError struct {
file string
err string
lex lex
}
func (e *ParseError) Error() (s string) {
if e.file != "" {
s = e.file + ": "
}
s += "dns: " + e.err + ": " + strconv.QuoteToASCII(e.lex.token) + " at line: " +
strconv.Itoa(e.lex.line) + ":" + strconv.Itoa(e.lex.column)
return
}
type lex struct {
token string // text of the token
tokenUpper string // uppercase text of the token
length int // length of the token
err bool // when true, token text has lexer error
value uint8 // value: zString, _BLANK, etc.
line int // line in the file
column int // column in the file
torc uint16 // type or class as parsed in the lexer, we only need to look this up in the grammar
comment string // any comment text seen
}
// Token holds the token that are returned when a zone file is parsed.
type Token struct {
// The scanned resource record when error is not nil.
RR
// When an error occurred, this has the error specifics.
Error *ParseError
// A potential comment positioned after the RR and on the same line.
Comment string
}
// NewRR reads the RR contained in the string s. Only the first RR is
// returned. If s contains no RR, return nil with no error. The class
// defaults to IN and TTL defaults to 3600. The full zone file syntax
// like $TTL, $ORIGIN, etc. is supported. All fields of the returned
// RR are set, except RR.Header().Rdlength which is set to 0.
func NewRR(s string) (RR, error) {
if len(s) > 0 && s[len(s)-1] != '\n' { // We need a closing newline
return ReadRR(strings.NewReader(s+"\n"), "")
}
return ReadRR(strings.NewReader(s), "")
}
// ReadRR reads the RR contained in q.
// See NewRR for more documentation.
func ReadRR(q io.Reader, filename string) (RR, error) {
r := <-parseZoneHelper(q, ".", filename, 1)
if r == nil {
return nil, nil
}
if r.Error != nil {
return nil, r.Error
}
return r.RR, nil
}
// ParseZone reads a RFC 1035 style zonefile from r. It returns *Tokens on the
// returned channel, which consist out the parsed RR, a potential comment or an error.
// If there is an error the RR is nil. The string file is only used
// in error reporting. The string origin is used as the initial origin, as
// if the file would start with: $ORIGIN origin .
// The directives $INCLUDE, $ORIGIN, $TTL and $GENERATE are supported.
// The channel t is closed by ParseZone when the end of r is reached.
//
// Basic usage pattern when reading from a string (z) containing the
// zone data:
//
// for x := range dns.ParseZone(strings.NewReader(z), "", "") {
// if x.Error != nil {
// // log.Println(x.Error)
// } else {
// // Do something with x.RR
// }
// }
//
// Comments specified after an RR (and on the same line!) are returned too:
//
// foo. IN A 10.0.0.1 ; this is a comment
//
// The text "; this is comment" is returned in Token.Comment. Comments inside the
// RR are discarded. Comments on a line by themselves are discarded too.
func ParseZone(r io.Reader, origin, file string) chan *Token {
return parseZoneHelper(r, origin, file, 10000)
}
func parseZoneHelper(r io.Reader, origin, file string, chansize int) chan *Token {
t := make(chan *Token, chansize)
go parseZone(r, origin, file, t, 0)
return t
}
func parseZone(r io.Reader, origin, f string, t chan *Token, include int) {
defer func() {
if include == 0 {
close(t)
}
}()
s := scanInit(r)
c := make(chan lex)
// Start the lexer
go zlexer(s, c)
// 6 possible beginnings of a line, _ is a space
// 0. zRRTYPE -> all omitted until the rrtype
// 1. zOwner _ zRrtype -> class/ttl omitted
// 2. zOwner _ zString _ zRrtype -> class omitted
// 3. zOwner _ zString _ zClass _ zRrtype -> ttl/class
// 4. zOwner _ zClass _ zRrtype -> ttl omitted
// 5. zOwner _ zClass _ zString _ zRrtype -> class/ttl (reversed)
// After detecting these, we know the zRrtype so we can jump to functions
// handling the rdata for each of these types.
if origin == "" {
origin = "."
}
origin = Fqdn(origin)
if _, ok := IsDomainName(origin); !ok {
t <- &Token{Error: &ParseError{f, "bad initial origin name", lex{}}}
return
}
st := zExpectOwnerDir // initial state
var h RR_Header
var defttl uint32 = defaultTtl
var prevName string
for l := range c {
// Lexer spotted an error already
if l.err == true {
t <- &Token{Error: &ParseError{f, l.token, l}}
return
}
switch st {
case zExpectOwnerDir:
// We can also expect a directive, like $TTL or $ORIGIN
h.Ttl = defttl
h.Class = ClassINET
switch l.value {
case zNewline:
st = zExpectOwnerDir
case zOwner:
h.Name = l.token
if l.token[0] == '@' {
h.Name = origin
prevName = h.Name
st = zExpectOwnerBl
break
}
if h.Name[l.length-1] != '.' {
h.Name = appendOrigin(h.Name, origin)
}
_, ok := IsDomainName(l.token)
if !ok {
t <- &Token{Error: &ParseError{f, "bad owner name", l}}
return
}
prevName = h.Name
st = zExpectOwnerBl
case zDirTtl:
st = zExpectDirTtlBl
case zDirOrigin:
st = zExpectDirOriginBl
case zDirInclude:
st = zExpectDirIncludeBl
case zDirGenerate:
st = zExpectDirGenerateBl
case zRrtpe:
h.Name = prevName
h.Rrtype = l.torc
st = zExpectRdata
case zClass:
h.Name = prevName
h.Class = l.torc
st = zExpectAnyNoClassBl
case zBlank:
// Discard, can happen when there is nothing on the
// line except the RR type
case zString:
ttl, ok := stringToTtl(l.token)
if !ok {
t <- &Token{Error: &ParseError{f, "not a TTL", l}}
return
}
h.Ttl = ttl
// Don't about the defttl, we should take the $TTL value
// defttl = ttl
st = zExpectAnyNoTtlBl
default:
t <- &Token{Error: &ParseError{f, "syntax error at beginning", l}}
return
}
case zExpectDirIncludeBl:
if l.value != zBlank {
t <- &Token{Error: &ParseError{f, "no blank after $INCLUDE-directive", l}}
return
}
st = zExpectDirInclude
case zExpectDirInclude:
if l.value != zString {
t <- &Token{Error: &ParseError{f, "expecting $INCLUDE value, not this...", l}}
return
}
neworigin := origin // There may be optionally a new origin set after the filename, if not use current one
l := <-c
switch l.value {
case zBlank:
l := <-c
if l.value == zString {
if _, ok := IsDomainName(l.token); !ok || l.length == 0 || l.err {
t <- &Token{Error: &ParseError{f, "bad origin name", l}}
return
}
// a new origin is specified.
if l.token[l.length-1] != '.' {
if origin != "." { // Prevent .. endings
neworigin = l.token + "." + origin
} else {
neworigin = l.token + origin
}
} else {
neworigin = l.token
}
}
case zNewline, zEOF:
// Ok
default:
t <- &Token{Error: &ParseError{f, "garbage after $INCLUDE", l}}
return
}
// Start with the new file
r1, e1 := os.Open(l.token)
if e1 != nil {
t <- &Token{Error: &ParseError{f, "failed to open `" + l.token + "'", l}}
return
}
if include+1 > 7 {
t <- &Token{Error: &ParseError{f, "too deeply nested $INCLUDE", l}}
return
}
parseZone(r1, l.token, neworigin, t, include+1)
st = zExpectOwnerDir
case zExpectDirTtlBl:
if l.value != zBlank {
t <- &Token{Error: &ParseError{f, "no blank after $TTL-directive", l}}
return
}
st = zExpectDirTtl
case zExpectDirTtl:
if l.value != zString {
t <- &Token{Error: &ParseError{f, "expecting $TTL value, not this...", l}}
return
}
if e, _ := slurpRemainder(c, f); e != nil {
t <- &Token{Error: e}
return
}
ttl, ok := stringToTtl(l.token)
if !ok {
t <- &Token{Error: &ParseError{f, "expecting $TTL value, not this...", l}}
return
}
defttl = ttl
st = zExpectOwnerDir
case zExpectDirOriginBl:
if l.value != zBlank {
t <- &Token{Error: &ParseError{f, "no blank after $ORIGIN-directive", l}}
return
}
st = zExpectDirOrigin
case zExpectDirOrigin:
if l.value != zString {
t <- &Token{Error: &ParseError{f, "expecting $ORIGIN value, not this...", l}}
return
}
if e, _ := slurpRemainder(c, f); e != nil {
t <- &Token{Error: e}
}
if _, ok := IsDomainName(l.token); !ok {
t <- &Token{Error: &ParseError{f, "bad origin name", l}}
return
}
if l.token[l.length-1] != '.' {
if origin != "." { // Prevent .. endings
origin = l.token + "." + origin
} else {
origin = l.token + origin
}
} else {
origin = l.token
}
st = zExpectOwnerDir
case zExpectDirGenerateBl:
if l.value != zBlank {
t <- &Token{Error: &ParseError{f, "no blank after $GENERATE-directive", l}}
return
}
st = zExpectDirGenerate
case zExpectDirGenerate:
if l.value != zString {
t <- &Token{Error: &ParseError{f, "expecting $GENERATE value, not this...", l}}
return
}
if errMsg := generate(l, c, t, origin); errMsg != "" {
t <- &Token{Error: &ParseError{f, errMsg, l}}
return
}
st = zExpectOwnerDir
case zExpectOwnerBl:
if l.value != zBlank {
t <- &Token{Error: &ParseError{f, "no blank after owner", l}}
return
}
st = zExpectAny
case zExpectAny:
switch l.value {
case zRrtpe:
h.Rrtype = l.torc
st = zExpectRdata
case zClass:
h.Class = l.torc
st = zExpectAnyNoClassBl
case zString:
ttl, ok := stringToTtl(l.token)
if !ok {
t <- &Token{Error: &ParseError{f, "not a TTL", l}}
return
}
h.Ttl = ttl
// defttl = ttl // don't set the defttl here
st = zExpectAnyNoTtlBl
default:
t <- &Token{Error: &ParseError{f, "expecting RR type, TTL or class, not this...", l}}
return
}
case zExpectAnyNoClassBl:
if l.value != zBlank {
t <- &Token{Error: &ParseError{f, "no blank before class", l}}
return
}
st = zExpectAnyNoClass
case zExpectAnyNoTtlBl:
if l.value != zBlank {
t <- &Token{Error: &ParseError{f, "no blank before TTL", l}}
return
}
st = zExpectAnyNoTtl
case zExpectAnyNoTtl:
switch l.value {
case zClass:
h.Class = l.torc
st = zExpectRrtypeBl
case zRrtpe:
h.Rrtype = l.torc
st = zExpectRdata
default:
t <- &Token{Error: &ParseError{f, "expecting RR type or class, not this...", l}}
return
}
case zExpectAnyNoClass:
switch l.value {
case zString:
ttl, ok := stringToTtl(l.token)
if !ok {
t <- &Token{Error: &ParseError{f, "not a TTL", l}}
return
}
h.Ttl = ttl
// defttl = ttl // don't set the def ttl anymore
st = zExpectRrtypeBl
case zRrtpe:
h.Rrtype = l.torc
st = zExpectRdata
default:
t <- &Token{Error: &ParseError{f, "expecting RR type or TTL, not this...", l}}
return
}
case zExpectRrtypeBl:
if l.value != zBlank {
t <- &Token{Error: &ParseError{f, "no blank before RR type", l}}
return
}
st = zExpectRrtype
case zExpectRrtype:
if l.value != zRrtpe {
t <- &Token{Error: &ParseError{f, "unknown RR type", l}}
return
}
h.Rrtype = l.torc
st = zExpectRdata
case zExpectRdata:
r, e, c1 := setRR(h, c, origin, f)
if e != nil {
// If e.lex is nil than we have encounter a unknown RR type
// in that case we substitute our current lex token
if e.lex.token == "" && e.lex.value == 0 {
e.lex = l // Uh, dirty
}
t <- &Token{Error: e}
return
}
t <- &Token{RR: r, Comment: c1}
st = zExpectOwnerDir
}
}
// If we get here, we and the h.Rrtype is still zero, we haven't parsed anything, this
// is not an error, because an empty zone file is still a zone file.
}
// zlexer scans the sourcefile and returns tokens on the channel c.
func zlexer(s *scan, c chan lex) {
var l lex
str := make([]byte, maxTok) // Should be enough for any token
stri := 0 // Offset in str (0 means empty)
com := make([]byte, maxTok) // Hold comment text
comi := 0
quote := false
escape := false
space := false
commt := false
rrtype := false
owner := true
brace := 0
x, err := s.tokenText()
defer close(c)
for err == nil {
l.column = s.position.Column
l.line = s.position.Line
if stri >= maxTok {
l.token = "token length insufficient for parsing"
l.err = true
debug.Printf("[%+v]", l.token)
c <- l
return
}
if comi >= maxTok {
l.token = "comment length insufficient for parsing"
l.err = true
debug.Printf("[%+v]", l.token)
c <- l
return
}
switch x {
case ' ', '\t':
if escape {
escape = false
str[stri] = x
stri++
break
}
if quote {
// Inside quotes this is legal
str[stri] = x
stri++
break
}
if commt {
com[comi] = x
comi++
break
}
if stri == 0 {
// Space directly in the beginning, handled in the grammar
} else if owner {
// If we have a string and its the first, make it an owner
l.value = zOwner
l.token = string(str[:stri])
l.tokenUpper = strings.ToUpper(l.token)
l.length = stri
// escape $... start with a \ not a $, so this will work
switch l.tokenUpper {
case "$TTL":
l.value = zDirTtl
case "$ORIGIN":
l.value = zDirOrigin
case "$INCLUDE":
l.value = zDirInclude
case "$GENERATE":
l.value = zDirGenerate
}
debug.Printf("[7 %+v]", l.token)
c <- l
} else {
l.value = zString
l.token = string(str[:stri])
l.tokenUpper = strings.ToUpper(l.token)
l.length = stri
if !rrtype {
if t, ok := StringToType[l.tokenUpper]; ok {
l.value = zRrtpe
l.torc = t
rrtype = true
} else {
if strings.HasPrefix(l.tokenUpper, "TYPE") {
t, ok := typeToInt(l.token)
if !ok {
l.token = "unknown RR type"
l.err = true
c <- l
return
}
l.value = zRrtpe
l.torc = t
}
}
if t, ok := StringToClass[l.tokenUpper]; ok {
l.value = zClass
l.torc = t
} else {
if strings.HasPrefix(l.tokenUpper, "CLASS") {
t, ok := classToInt(l.token)
if !ok {
l.token = "unknown class"
l.err = true
c <- l
return
}
l.value = zClass
l.torc = t
}
}
}
debug.Printf("[6 %+v]", l.token)
c <- l
}
stri = 0
// I reverse space stuff here
if !space && !commt {
l.value = zBlank
l.token = " "
l.length = 1
debug.Printf("[5 %+v]", l.token)
c <- l
}
owner = false
space = true
case ';':
if escape {
escape = false
str[stri] = x
stri++
break
}
if quote {
// Inside quotes this is legal
str[stri] = x
stri++
break
}
if stri > 0 {
l.value = zString
l.token = string(str[:stri])
l.tokenUpper = strings.ToUpper(l.token)
l.length = stri
debug.Printf("[4 %+v]", l.token)
c <- l
stri = 0
}
commt = true
com[comi] = ';'
comi++
case '\r':
escape = false
if quote {
str[stri] = x
stri++
break
}
// discard if outside of quotes
case '\n':
escape = false
// Escaped newline
if quote {
str[stri] = x
stri++
break
}
// inside quotes this is legal
if commt {
// Reset a comment
commt = false
rrtype = false
stri = 0
// If not in a brace this ends the comment AND the RR
if brace == 0 {
owner = true
owner = true
l.value = zNewline
l.token = "\n"
l.tokenUpper = l.token
l.length = 1
l.comment = string(com[:comi])
debug.Printf("[3 %+v %+v]", l.token, l.comment)
c <- l
l.comment = ""
comi = 0
break
}
com[comi] = ' ' // convert newline to space
comi++
break
}
if brace == 0 {
// If there is previous text, we should output it here
if stri != 0 {
l.value = zString
l.token = string(str[:stri])
l.tokenUpper = strings.ToUpper(l.token)
l.length = stri
if !rrtype {
if t, ok := StringToType[l.tokenUpper]; ok {
l.value = zRrtpe
l.torc = t
rrtype = true
}
}
debug.Printf("[2 %+v]", l.token)
c <- l
}
l.value = zNewline
l.token = "\n"
l.tokenUpper = l.token
l.length = 1
debug.Printf("[1 %+v]", l.token)
c <- l
stri = 0
commt = false
rrtype = false
owner = true
comi = 0
}
case '\\':
// comments do not get escaped chars, everything is copied
if commt {
com[comi] = x
comi++
break
}
// something already escaped must be in string
if escape {
str[stri] = x
stri++
escape = false
break
}
// something escaped outside of string gets added to string
str[stri] = x
stri++
escape = true
case '"':
if commt {
com[comi] = x
comi++
break
}
if escape {
str[stri] = x
stri++
escape = false
break
}
space = false
// send previous gathered text and the quote
if stri != 0 {
l.value = zString
l.token = string(str[:stri])
l.tokenUpper = strings.ToUpper(l.token)
l.length = stri
debug.Printf("[%+v]", l.token)
c <- l
stri = 0
}
// send quote itself as separate token
l.value = zQuote
l.token = "\""
l.tokenUpper = l.token
l.length = 1
c <- l
quote = !quote
case '(', ')':
if commt {
com[comi] = x
comi++
break
}
if escape {
str[stri] = x
stri++
escape = false
break
}
if quote {
str[stri] = x
stri++
break
}
switch x {
case ')':
brace--
if brace < 0 {
l.token = "extra closing brace"
l.tokenUpper = l.token
l.err = true
debug.Printf("[%+v]", l.token)
c <- l
return
}
case '(':
brace++
}
default:
escape = false
if commt {
com[comi] = x
comi++
break
}
str[stri] = x
stri++
space = false
}
x, err = s.tokenText()
}
if stri > 0 {
// Send remainder
l.token = string(str[:stri])
l.tokenUpper = strings.ToUpper(l.token)
l.length = stri
l.value = zString
debug.Printf("[%+v]", l.token)
c <- l
}
}
// Extract the class number from CLASSxx
func classToInt(token string) (uint16, bool) {
offset := 5
if len(token) < offset+1 {
return 0, false
}
class, ok := strconv.Atoi(token[offset:])
if ok != nil || class > maxUint16 {
return 0, false
}
return uint16(class), true
}
// Extract the rr number from TYPExxx
func typeToInt(token string) (uint16, bool) {
offset := 4
if len(token) < offset+1 {
return 0, false
}
typ, ok := strconv.Atoi(token[offset:])
if ok != nil || typ > maxUint16 {
return 0, false
}
return uint16(typ), true
}
// Parse things like 2w, 2m, etc, Return the time in seconds.
func stringToTtl(token string) (uint32, bool) {
s := uint32(0)
i := uint32(0)
for _, c := range token {
switch c {
case 's', 'S':
s += i
i = 0
case 'm', 'M':
s += i * 60
i = 0
case 'h', 'H':
s += i * 60 * 60
i = 0
case 'd', 'D':
s += i * 60 * 60 * 24
i = 0
case 'w', 'W':
s += i * 60 * 60 * 24 * 7
i = 0
case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
i *= 10
i += uint32(c) - '0'
default:
return 0, false
}
}
return s + i, true
}
// Parse LOC records' <digits>[.<digits>][mM] into a
// mantissa exponent format. Token should contain the entire
// string (i.e. no spaces allowed)
func stringToCm(token string) (e, m uint8, ok bool) {
if token[len(token)-1] == 'M' || token[len(token)-1] == 'm' {
token = token[0 : len(token)-1]
}
s := strings.SplitN(token, ".", 2)
var meters, cmeters, val int
var err error
switch len(s) {
case 2:
if cmeters, err = strconv.Atoi(s[1]); err != nil {
return
}
fallthrough
case 1:
if meters, err = strconv.Atoi(s[0]); err != nil {
return
}
case 0:
// huh?
return 0, 0, false
}
ok = true
if meters > 0 {
e = 2
val = meters
} else {
e = 0
val = cmeters
}
for val > 10 {
e++
val /= 10
}
if e > 9 {
ok = false
}
m = uint8(val)
return
}
func appendOrigin(name, origin string) string {
if origin == "." {
return name + origin
}
return name + "." + origin
}
// LOC record helper function
func locCheckNorth(token string, latitude uint32) (uint32, bool) {
switch token {
case "n", "N":
return LOC_EQUATOR + latitude, true
case "s", "S":
return LOC_EQUATOR - latitude, true
}
return latitude, false
}
// LOC record helper function
func locCheckEast(token string, longitude uint32) (uint32, bool) {
switch token {
case "e", "E":
return LOC_EQUATOR + longitude, true
case "w", "W":
return LOC_EQUATOR - longitude, true
}
return longitude, false
}
// "Eat" the rest of the "line". Return potential comments
func slurpRemainder(c chan lex, f string) (*ParseError, string) {
l := <-c
com := ""
switch l.value {
case zBlank:
l = <-c
com = l.comment
if l.value != zNewline && l.value != zEOF {
return &ParseError{f, "garbage after rdata", l}, ""
}
case zNewline:
com = l.comment
case zEOF:
default:
return &ParseError{f, "garbage after rdata", l}, ""
}
return nil, com
}
// Parse a 64 bit-like ipv6 address: "0014:4fff:ff20:ee64"
// Used for NID and L64 record.
func stringToNodeID(l lex) (uint64, *ParseError) {
if len(l.token) < 19 {
return 0, &ParseError{l.token, "bad NID/L64 NodeID/Locator64", l}
}
// There must be three colons at fixes postitions, if not its a parse error
if l.token[4] != ':' && l.token[9] != ':' && l.token[14] != ':' {
return 0, &ParseError{l.token, "bad NID/L64 NodeID/Locator64", l}
}
s := l.token[0:4] + l.token[5:9] + l.token[10:14] + l.token[15:19]
u, err := strconv.ParseUint(s, 16, 64)
if err != nil {
return 0, &ParseError{l.token, "bad NID/L64 NodeID/Locator64", l}
}
return u, nil
}