1008 lines
24 KiB
Go
1008 lines
24 KiB
Go
package dns
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import (
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"fmt"
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"io"
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"os"
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"path/filepath"
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"strconv"
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"strings"
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)
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const maxTok = 2048 // Largest token we can return.
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const maxUint16 = 1<<16 - 1
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// Tokinize a RFC 1035 zone file. The tokenizer will normalize it:
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// * Add ownernames if they are left blank;
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// * Suppress sequences of spaces;
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// * Make each RR fit on one line (_NEWLINE is send as last)
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// * Handle comments: ;
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// * Handle braces - anywhere.
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const (
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// Zonefile
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zEOF = iota
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zString
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zBlank
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zQuote
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zNewline
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zRrtpe
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zOwner
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zClass
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zDirOrigin // $ORIGIN
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zDirTTL // $TTL
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zDirInclude // $INCLUDE
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zDirGenerate // $GENERATE
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// Privatekey file
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zValue
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zKey
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zExpectOwnerDir // Ownername
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zExpectOwnerBl // Whitespace after the ownername
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zExpectAny // Expect rrtype, ttl or class
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zExpectAnyNoClass // Expect rrtype or ttl
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zExpectAnyNoClassBl // The whitespace after _EXPECT_ANY_NOCLASS
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zExpectAnyNoTTL // Expect rrtype or class
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zExpectAnyNoTTLBl // Whitespace after _EXPECT_ANY_NOTTL
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zExpectRrtype // Expect rrtype
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zExpectRrtypeBl // Whitespace BEFORE rrtype
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zExpectRdata // The first element of the rdata
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zExpectDirTTLBl // Space after directive $TTL
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zExpectDirTTL // Directive $TTL
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zExpectDirOriginBl // Space after directive $ORIGIN
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zExpectDirOrigin // Directive $ORIGIN
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zExpectDirIncludeBl // Space after directive $INCLUDE
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zExpectDirInclude // Directive $INCLUDE
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zExpectDirGenerate // Directive $GENERATE
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zExpectDirGenerateBl // Space after directive $GENERATE
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)
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// ParseError is a parsing error. It contains the parse error and the location in the io.Reader
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// where the error occurred.
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type ParseError struct {
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file string
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err string
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lex lex
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}
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func (e *ParseError) Error() (s string) {
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if e.file != "" {
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s = e.file + ": "
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}
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s += "dns: " + e.err + ": " + strconv.QuoteToASCII(e.lex.token) + " at line: " +
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strconv.Itoa(e.lex.line) + ":" + strconv.Itoa(e.lex.column)
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return
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}
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type lex struct {
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token string // text of the token
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tokenUpper string // uppercase text of the token
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length int // length of the token
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err bool // when true, token text has lexer error
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value uint8 // value: zString, _BLANK, etc.
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line int // line in the file
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column int // column in the file
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torc uint16 // type or class as parsed in the lexer, we only need to look this up in the grammar
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comment string // any comment text seen
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}
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// Token holds the token that are returned when a zone file is parsed.
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type Token struct {
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// The scanned resource record when error is not nil.
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RR
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// When an error occurred, this has the error specifics.
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Error *ParseError
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// A potential comment positioned after the RR and on the same line.
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Comment string
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}
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// ttlState describes the state necessary to fill in an omitted RR TTL
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type ttlState struct {
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ttl uint32 // ttl is the current default TTL
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isByDirective bool // isByDirective indicates whether ttl was set by a $TTL directive
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}
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// NewRR reads the RR contained in the string s. Only the first RR is
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// returned. If s contains no RR, return nil with no error. The class
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// defaults to IN and TTL defaults to 3600. The full zone file syntax
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// like $TTL, $ORIGIN, etc. is supported. All fields of the returned
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// RR are set, except RR.Header().Rdlength which is set to 0.
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func NewRR(s string) (RR, error) {
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if len(s) > 0 && s[len(s)-1] != '\n' { // We need a closing newline
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return ReadRR(strings.NewReader(s+"\n"), "")
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}
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return ReadRR(strings.NewReader(s), "")
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}
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// ReadRR reads the RR contained in q.
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// See NewRR for more documentation.
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func ReadRR(q io.Reader, filename string) (RR, error) {
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defttl := &ttlState{defaultTtl, false}
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r := <-parseZoneHelper(q, ".", filename, defttl, 1)
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if r == nil {
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return nil, nil
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}
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if r.Error != nil {
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return nil, r.Error
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}
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return r.RR, nil
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}
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// ParseZone reads a RFC 1035 style zonefile from r. It returns *Tokens on the
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// returned channel, each consisting of either a parsed RR and optional comment
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// or a nil RR and an error. The string file is only used
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// in error reporting. The string origin is used as the initial origin, as
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// if the file would start with an $ORIGIN directive.
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// The directives $INCLUDE, $ORIGIN, $TTL and $GENERATE are supported.
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// The channel t is closed by ParseZone when the end of r is reached.
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//
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// Basic usage pattern when reading from a string (z) containing the
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// zone data:
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//
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// for x := range dns.ParseZone(strings.NewReader(z), "", "") {
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// if x.Error != nil {
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// // log.Println(x.Error)
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// } else {
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// // Do something with x.RR
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// }
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// }
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//
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// Comments specified after an RR (and on the same line!) are returned too:
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//
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// foo. IN A 10.0.0.1 ; this is a comment
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//
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// The text "; this is comment" is returned in Token.Comment. Comments inside the
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// RR are discarded. Comments on a line by themselves are discarded too.
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func ParseZone(r io.Reader, origin, file string) chan *Token {
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return parseZoneHelper(r, origin, file, nil, 10000)
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}
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func parseZoneHelper(r io.Reader, origin, file string, defttl *ttlState, chansize int) chan *Token {
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t := make(chan *Token, chansize)
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go parseZone(r, origin, file, defttl, t, 0)
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return t
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}
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func parseZone(r io.Reader, origin, f string, defttl *ttlState, t chan *Token, include int) {
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defer func() {
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if include == 0 {
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close(t)
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}
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}()
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s, cancel := scanInit(r)
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c := make(chan lex)
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// Start the lexer
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go zlexer(s, c)
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defer func() {
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cancel()
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// zlexer can send up to three tokens, the next one and possibly 2 remainders.
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// Do a non-blocking read.
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_, ok := <-c
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_, ok = <-c
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_, ok = <-c
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if !ok {
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// too bad
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}
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}()
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// 6 possible beginnings of a line, _ is a space
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// 0. zRRTYPE -> all omitted until the rrtype
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// 1. zOwner _ zRrtype -> class/ttl omitted
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// 2. zOwner _ zString _ zRrtype -> class omitted
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// 3. zOwner _ zString _ zClass _ zRrtype -> ttl/class
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// 4. zOwner _ zClass _ zRrtype -> ttl omitted
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// 5. zOwner _ zClass _ zString _ zRrtype -> class/ttl (reversed)
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// After detecting these, we know the zRrtype so we can jump to functions
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// handling the rdata for each of these types.
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if origin != "" {
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origin = Fqdn(origin)
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if _, ok := IsDomainName(origin); !ok {
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t <- &Token{Error: &ParseError{f, "bad initial origin name", lex{}}}
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return
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}
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}
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st := zExpectOwnerDir // initial state
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var h RR_Header
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var prevName string
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for l := range c {
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// Lexer spotted an error already
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if l.err == true {
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t <- &Token{Error: &ParseError{f, l.token, l}}
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return
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}
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switch st {
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case zExpectOwnerDir:
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// We can also expect a directive, like $TTL or $ORIGIN
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if defttl != nil {
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h.Ttl = defttl.ttl
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}
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h.Class = ClassINET
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switch l.value {
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case zNewline:
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st = zExpectOwnerDir
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case zOwner:
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h.Name = l.token
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name, ok := toAbsoluteName(l.token, origin)
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if !ok {
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t <- &Token{Error: &ParseError{f, "bad owner name", l}}
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return
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}
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h.Name = name
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prevName = h.Name
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st = zExpectOwnerBl
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case zDirTTL:
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st = zExpectDirTTLBl
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case zDirOrigin:
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st = zExpectDirOriginBl
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case zDirInclude:
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st = zExpectDirIncludeBl
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case zDirGenerate:
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st = zExpectDirGenerateBl
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case zRrtpe:
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h.Name = prevName
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h.Rrtype = l.torc
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st = zExpectRdata
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case zClass:
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h.Name = prevName
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h.Class = l.torc
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st = zExpectAnyNoClassBl
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case zBlank:
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// Discard, can happen when there is nothing on the
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// line except the RR type
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case zString:
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ttl, ok := stringToTTL(l.token)
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if !ok {
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t <- &Token{Error: &ParseError{f, "not a TTL", l}}
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return
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}
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h.Ttl = ttl
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if defttl == nil || !defttl.isByDirective {
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defttl = &ttlState{ttl, false}
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}
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st = zExpectAnyNoTTLBl
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default:
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t <- &Token{Error: &ParseError{f, "syntax error at beginning", l}}
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return
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}
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case zExpectDirIncludeBl:
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if l.value != zBlank {
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t <- &Token{Error: &ParseError{f, "no blank after $INCLUDE-directive", l}}
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return
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}
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st = zExpectDirInclude
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case zExpectDirInclude:
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if l.value != zString {
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t <- &Token{Error: &ParseError{f, "expecting $INCLUDE value, not this...", l}}
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return
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}
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neworigin := origin // There may be optionally a new origin set after the filename, if not use current one
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switch l := <-c; l.value {
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case zBlank:
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l := <-c
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if l.value == zString {
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name, ok := toAbsoluteName(l.token, origin)
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if !ok {
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t <- &Token{Error: &ParseError{f, "bad origin name", l}}
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return
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}
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neworigin = name
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}
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case zNewline, zEOF:
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// Ok
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default:
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t <- &Token{Error: &ParseError{f, "garbage after $INCLUDE", l}}
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return
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}
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// Start with the new file
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includePath := l.token
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if !filepath.IsAbs(includePath) {
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includePath = filepath.Join(filepath.Dir(f), includePath)
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}
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r1, e1 := os.Open(includePath)
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if e1 != nil {
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msg := fmt.Sprintf("failed to open `%s'", l.token)
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if !filepath.IsAbs(l.token) {
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msg += fmt.Sprintf(" as `%s'", includePath)
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}
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t <- &Token{Error: &ParseError{f, msg, l}}
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return
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}
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if include+1 > 7 {
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t <- &Token{Error: &ParseError{f, "too deeply nested $INCLUDE", l}}
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return
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}
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parseZone(r1, neworigin, includePath, defttl, t, include+1)
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st = zExpectOwnerDir
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case zExpectDirTTLBl:
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if l.value != zBlank {
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t <- &Token{Error: &ParseError{f, "no blank after $TTL-directive", l}}
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return
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}
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st = zExpectDirTTL
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case zExpectDirTTL:
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if l.value != zString {
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t <- &Token{Error: &ParseError{f, "expecting $TTL value, not this...", l}}
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return
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}
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if e, _ := slurpRemainder(c, f); e != nil {
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t <- &Token{Error: e}
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return
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}
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ttl, ok := stringToTTL(l.token)
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if !ok {
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t <- &Token{Error: &ParseError{f, "expecting $TTL value, not this...", l}}
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return
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}
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defttl = &ttlState{ttl, true}
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st = zExpectOwnerDir
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case zExpectDirOriginBl:
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if l.value != zBlank {
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t <- &Token{Error: &ParseError{f, "no blank after $ORIGIN-directive", l}}
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return
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}
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st = zExpectDirOrigin
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case zExpectDirOrigin:
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if l.value != zString {
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t <- &Token{Error: &ParseError{f, "expecting $ORIGIN value, not this...", l}}
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return
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}
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if e, _ := slurpRemainder(c, f); e != nil {
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t <- &Token{Error: e}
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}
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name, ok := toAbsoluteName(l.token, origin)
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if !ok {
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t <- &Token{Error: &ParseError{f, "bad origin name", l}}
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return
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}
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origin = name
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st = zExpectOwnerDir
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case zExpectDirGenerateBl:
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if l.value != zBlank {
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t <- &Token{Error: &ParseError{f, "no blank after $GENERATE-directive", l}}
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return
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}
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st = zExpectDirGenerate
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case zExpectDirGenerate:
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if l.value != zString {
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t <- &Token{Error: &ParseError{f, "expecting $GENERATE value, not this...", l}}
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return
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}
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if errMsg := generate(l, c, t, origin); errMsg != "" {
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t <- &Token{Error: &ParseError{f, errMsg, l}}
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return
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}
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st = zExpectOwnerDir
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case zExpectOwnerBl:
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if l.value != zBlank {
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t <- &Token{Error: &ParseError{f, "no blank after owner", l}}
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return
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}
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st = zExpectAny
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case zExpectAny:
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switch l.value {
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case zRrtpe:
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if defttl == nil {
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t <- &Token{Error: &ParseError{f, "missing TTL with no previous value", l}}
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return
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}
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h.Rrtype = l.torc
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st = zExpectRdata
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case zClass:
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h.Class = l.torc
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st = zExpectAnyNoClassBl
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case zString:
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ttl, ok := stringToTTL(l.token)
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if !ok {
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t <- &Token{Error: &ParseError{f, "not a TTL", l}}
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return
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}
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h.Ttl = ttl
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if defttl == nil || !defttl.isByDirective {
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defttl = &ttlState{ttl, false}
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}
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st = zExpectAnyNoTTLBl
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default:
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t <- &Token{Error: &ParseError{f, "expecting RR type, TTL or class, not this...", l}}
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return
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}
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case zExpectAnyNoClassBl:
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if l.value != zBlank {
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t <- &Token{Error: &ParseError{f, "no blank before class", l}}
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return
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}
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st = zExpectAnyNoClass
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case zExpectAnyNoTTLBl:
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if l.value != zBlank {
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t <- &Token{Error: &ParseError{f, "no blank before TTL", l}}
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return
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}
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st = zExpectAnyNoTTL
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case zExpectAnyNoTTL:
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switch l.value {
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case zClass:
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h.Class = l.torc
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st = zExpectRrtypeBl
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case zRrtpe:
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h.Rrtype = l.torc
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st = zExpectRdata
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default:
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t <- &Token{Error: &ParseError{f, "expecting RR type or class, not this...", l}}
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return
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}
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case zExpectAnyNoClass:
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switch l.value {
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case zString:
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ttl, ok := stringToTTL(l.token)
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if !ok {
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t <- &Token{Error: &ParseError{f, "not a TTL", l}}
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return
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}
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h.Ttl = ttl
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if defttl == nil || !defttl.isByDirective {
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defttl = &ttlState{ttl, false}
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}
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st = zExpectRrtypeBl
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case zRrtpe:
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h.Rrtype = l.torc
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st = zExpectRdata
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default:
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t <- &Token{Error: &ParseError{f, "expecting RR type or TTL, not this...", l}}
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return
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}
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case zExpectRrtypeBl:
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if l.value != zBlank {
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t <- &Token{Error: &ParseError{f, "no blank before RR type", l}}
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return
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}
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st = zExpectRrtype
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case zExpectRrtype:
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if l.value != zRrtpe {
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t <- &Token{Error: &ParseError{f, "unknown RR type", l}}
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return
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}
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h.Rrtype = l.torc
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st = zExpectRdata
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case zExpectRdata:
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r, e, c1 := setRR(h, c, origin, f)
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if e != nil {
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// If e.lex is nil than we have encounter a unknown RR type
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// in that case we substitute our current lex token
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if e.lex.token == "" && e.lex.value == 0 {
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e.lex = l // Uh, dirty
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}
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t <- &Token{Error: e}
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return
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}
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t <- &Token{RR: r, Comment: c1}
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st = zExpectOwnerDir
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}
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}
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// If we get here, we and the h.Rrtype is still zero, we haven't parsed anything, this
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// is not an error, because an empty zone file is still a zone file.
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}
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// zlexer scans the sourcefile and returns tokens on the channel c.
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func zlexer(s *scan, c chan lex) {
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var l lex
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str := make([]byte, maxTok) // Should be enough for any token
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stri := 0 // Offset in str (0 means empty)
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com := make([]byte, maxTok) // Hold comment text
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comi := 0
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quote := false
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escape := false
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space := false
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commt := false
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rrtype := false
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owner := true
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brace := 0
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x, err := s.tokenText()
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defer close(c)
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for err == nil {
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l.column = s.position.Column
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l.line = s.position.Line
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if stri >= maxTok {
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l.token = "token length insufficient for parsing"
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l.err = true
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c <- l
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return
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|
}
|
|
if comi >= maxTok {
|
|
l.token = "comment length insufficient for parsing"
|
|
l.err = true
|
|
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
|
|
}
|
|
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
|
|
rrtype = true
|
|
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
|
|
}
|
|
}
|
|
}
|
|
c <- l
|
|
}
|
|
stri = 0
|
|
|
|
if !space && !commt {
|
|
l.value = zBlank
|
|
l.token = " "
|
|
l.length = 1
|
|
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
|
|
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])
|
|
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
|
|
}
|
|
}
|
|
c <- l
|
|
}
|
|
l.value = zNewline
|
|
l.token = "\n"
|
|
l.tokenUpper = l.token
|
|
l.length = 1
|
|
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
|
|
|
|
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
|
|
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
|
|
c <- l
|
|
}
|
|
if brace != 0 {
|
|
l.token = "unbalanced brace"
|
|
l.tokenUpper = l.token
|
|
l.err = true
|
|
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, err := strconv.ParseUint(token[offset:], 10, 16)
|
|
if err != nil {
|
|
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, err := strconv.ParseUint(token[offset:], 10, 16)
|
|
if err != nil {
|
|
return 0, false
|
|
}
|
|
return uint16(typ), true
|
|
}
|
|
|
|
// stringToTTL parses things like 2w, 2m, etc, and returns 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 toAbsoluteName(name, origin string) (absolute string, ok bool) {
|
|
// check for an explicit origin reference
|
|
if name == "@" {
|
|
// require a nonempty origin
|
|
if origin == "" {
|
|
return "", false
|
|
}
|
|
return origin, true
|
|
}
|
|
|
|
// require a valid domain name
|
|
_, ok = IsDomainName(name)
|
|
if !ok || name == "" {
|
|
return "", false
|
|
}
|
|
|
|
// check if name is already absolute
|
|
if name[len(name)-1] == '.' {
|
|
return name, true
|
|
}
|
|
|
|
// require a nonempty origin
|
|
if origin == "" {
|
|
return "", false
|
|
}
|
|
return appendOrigin(name, origin), true
|
|
}
|
|
|
|
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
|
|
}
|