1406 lines
31 KiB
Go
1406 lines
31 KiB
Go
package dns
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import (
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"bufio"
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"fmt"
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"io"
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"io/fs"
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"os"
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"path"
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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 = 512 // Token buffer start size, and growth size amount.
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// The maximum depth of $INCLUDE directives supported by the
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// ZoneParser API.
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const maxIncludeDepth = 7
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// Tokenize 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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wrappedErr error
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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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if e.err == "" && e.wrappedErr != nil {
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e.err = e.wrappedErr.Error()
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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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func (e *ParseError) Unwrap() error { return e.wrappedErr }
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type lex struct {
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token string // text 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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torc uint16 // type or class as parsed in the lexer, we only need to look this up in the grammar
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line int // line in the file
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column int // column in the file
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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 a string s and returns the first RR.
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// If s contains no records, NewRR will return nil with no error.
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//
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// The class defaults to IN, TTL defaults to 3600, and
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// origin for resolving relative domain names defaults to the DNS root (.).
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// Full zone file syntax is supported, including directives like $TTL and $ORIGIN.
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// All fields of the returned RR are set from the read data, 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 r.
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//
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// The string file is used in error reporting and to resolve relative
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// $INCLUDE directives.
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//
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// See NewRR for more documentation.
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func ReadRR(r io.Reader, file string) (RR, error) {
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zp := NewZoneParser(r, ".", file)
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zp.SetDefaultTTL(defaultTtl)
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zp.SetIncludeAllowed(true)
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rr, _ := zp.Next()
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return rr, zp.Err()
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}
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// ZoneParser is a parser for an RFC 1035 style zonefile.
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//
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// Each parsed RR in the zone is returned sequentially from Next. An
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// optional comment can be retrieved with Comment.
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//
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// The directives $INCLUDE, $ORIGIN, $TTL and $GENERATE are all
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// supported. Although $INCLUDE is disabled by default.
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// Note that $GENERATE's range support up to a maximum of 65535 steps.
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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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// zp := NewZoneParser(strings.NewReader(z), "", "")
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//
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// for rr, ok := zp.Next(); ok; rr, ok = zp.Next() {
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// // Do something with rr
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// }
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//
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// if err := zp.Err(); err != nil {
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// // log.Println(err)
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// }
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//
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// Comments specified after an RR (and on the same line!) are
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// 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 from Comment. Comments inside
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// the RR are returned concatenated along with the RR. Comments on a line
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// by themselves are discarded.
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//
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// Callers should not assume all returned data in an Resource Record is
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// syntactically correct, e.g. illegal base64 in RRSIGs will be returned as-is.
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type ZoneParser struct {
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c *zlexer
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parseErr *ParseError
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origin string
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file string
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defttl *ttlState
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h RR_Header
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// sub is used to parse $INCLUDE files and $GENERATE directives.
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// Next, by calling subNext, forwards the resulting RRs from this
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// sub parser to the calling code.
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sub *ZoneParser
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r io.Reader
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fsys fs.FS
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includeDepth uint8
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includeAllowed bool
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generateDisallowed bool
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}
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// NewZoneParser returns an RFC 1035 style zonefile parser that reads
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// from r.
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//
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// The string file is used in error reporting and to resolve relative
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// $INCLUDE directives. The string origin is used as the initial
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// origin, as if the file would start with an $ORIGIN directive.
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func NewZoneParser(r io.Reader, origin, file string) *ZoneParser {
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var pe *ParseError
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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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pe = &ParseError{file: file, err: "bad initial origin name"}
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}
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}
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return &ZoneParser{
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c: newZLexer(r),
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parseErr: pe,
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origin: origin,
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file: file,
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}
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}
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// SetDefaultTTL sets the parsers default TTL to ttl.
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func (zp *ZoneParser) SetDefaultTTL(ttl uint32) {
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zp.defttl = &ttlState{ttl, false}
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}
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// SetIncludeAllowed controls whether $INCLUDE directives are
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// allowed. $INCLUDE directives are not supported by default.
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//
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// The $INCLUDE directive will open and read from a user controlled
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// file on the system. Even if the file is not a valid zonefile, the
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// contents of the file may be revealed in error messages, such as:
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//
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// /etc/passwd: dns: not a TTL: "root:x:0:0:root:/root:/bin/bash" at line: 1:31
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// /etc/shadow: dns: not a TTL: "root:$6$<redacted>::0:99999:7:::" at line: 1:125
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func (zp *ZoneParser) SetIncludeAllowed(v bool) {
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zp.includeAllowed = v
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}
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// SetIncludeFS provides an [fs.FS] to use when looking for the target of
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// $INCLUDE directives. ($INCLUDE must still be enabled separately by calling
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// [ZoneParser.SetIncludeAllowed].) If fsys is nil, [os.Open] will be used.
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//
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// When fsys is an on-disk FS, the ability of $INCLUDE to reach files from
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// outside its root directory depends upon the FS implementation. For
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// instance, [os.DirFS] will refuse to open paths like "../../etc/passwd",
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// however it will still follow links which may point anywhere on the system.
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//
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// FS paths are slash-separated on all systems, even Windows. $INCLUDE paths
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// containing other characters such as backslash and colon may be accepted as
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// valid, but those characters will never be interpreted by an FS
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// implementation as path element separators. See [fs.ValidPath] for more
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// details.
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func (zp *ZoneParser) SetIncludeFS(fsys fs.FS) {
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zp.fsys = fsys
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}
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// Err returns the first non-EOF error that was encountered by the
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// ZoneParser.
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func (zp *ZoneParser) Err() error {
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if zp.parseErr != nil {
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return zp.parseErr
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}
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if zp.sub != nil {
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if err := zp.sub.Err(); err != nil {
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return err
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}
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}
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return zp.c.Err()
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}
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func (zp *ZoneParser) setParseError(err string, l lex) (RR, bool) {
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zp.parseErr = &ParseError{file: zp.file, err: err, lex: l}
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return nil, false
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}
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// Comment returns an optional text comment that occurred alongside
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// the RR.
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func (zp *ZoneParser) Comment() string {
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if zp.parseErr != nil {
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return ""
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}
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if zp.sub != nil {
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return zp.sub.Comment()
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}
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return zp.c.Comment()
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}
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func (zp *ZoneParser) subNext() (RR, bool) {
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if rr, ok := zp.sub.Next(); ok {
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return rr, true
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}
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if zp.sub.r != nil {
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if c, ok := zp.sub.r.(io.Closer); ok {
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c.Close()
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}
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zp.sub.r = nil
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}
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if zp.sub.Err() != nil {
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// We have errors to surface.
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return nil, false
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}
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zp.sub = nil
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return zp.Next()
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}
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// Next advances the parser to the next RR in the zonefile and
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// returns the (RR, true). It will return (nil, false) when the
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// parsing stops, either by reaching the end of the input or an
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// error. After Next returns (nil, false), the Err method will return
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// any error that occurred during parsing.
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func (zp *ZoneParser) Next() (RR, bool) {
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if zp.parseErr != nil {
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return nil, false
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}
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if zp.sub != nil {
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return zp.subNext()
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}
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// 6 possible beginnings of a line (_ is a space):
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//
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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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//
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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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st := zExpectOwnerDir // initial state
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h := &zp.h
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for l, ok := zp.c.Next(); ok; l, ok = zp.c.Next() {
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// zlexer spotted an error already
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if l.err {
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return zp.setParseError(l.token, l)
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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 zp.defttl != nil {
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h.Ttl = zp.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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name, ok := toAbsoluteName(l.token, zp.origin)
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if !ok {
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return zp.setParseError("bad owner name", l)
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}
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h.Name = 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.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 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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return zp.setParseError("not a TTL", l)
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}
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h.Ttl = ttl
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if zp.defttl == nil || !zp.defttl.isByDirective {
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zp.defttl = &ttlState{ttl, false}
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}
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st = zExpectAnyNoTTLBl
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default:
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return zp.setParseError("syntax error at beginning", l)
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}
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case zExpectDirIncludeBl:
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if l.value != zBlank {
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return zp.setParseError("no blank after $INCLUDE-directive", l)
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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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return zp.setParseError("expecting $INCLUDE value, not this...", l)
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}
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neworigin := zp.origin // There may be optionally a new origin set after the filename, if not use current one
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switch l, _ := zp.c.Next(); l.value {
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case zBlank:
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l, _ := zp.c.Next()
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if l.value == zString {
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name, ok := toAbsoluteName(l.token, zp.origin)
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if !ok {
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return zp.setParseError("bad origin name", l)
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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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return zp.setParseError("garbage after $INCLUDE", l)
|
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}
|
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|
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if !zp.includeAllowed {
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return zp.setParseError("$INCLUDE directive not allowed", l)
|
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}
|
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if zp.includeDepth >= maxIncludeDepth {
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return zp.setParseError("too deeply nested $INCLUDE", l)
|
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}
|
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|
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// Start with the new file
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includePath := l.token
|
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var r1 io.Reader
|
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var e1 error
|
|
if zp.fsys != nil {
|
|
// fs.FS always uses / as separator, even on Windows, so use
|
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// path instead of filepath here:
|
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if !path.IsAbs(includePath) {
|
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includePath = path.Join(path.Dir(zp.file), includePath)
|
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}
|
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|
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// os.DirFS, and probably others, expect all paths to be
|
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// relative, so clean the path and remove leading / if
|
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// present:
|
|
includePath = strings.TrimLeft(path.Clean(includePath), "/")
|
|
|
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r1, e1 = zp.fsys.Open(includePath)
|
|
} else {
|
|
if !filepath.IsAbs(includePath) {
|
|
includePath = filepath.Join(filepath.Dir(zp.file), includePath)
|
|
}
|
|
r1, e1 = os.Open(includePath)
|
|
}
|
|
if e1 != nil {
|
|
var as string
|
|
if includePath != l.token {
|
|
as = fmt.Sprintf(" as `%s'", includePath)
|
|
}
|
|
zp.parseErr = &ParseError{
|
|
file: zp.file,
|
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wrappedErr: fmt.Errorf("failed to open `%s'%s: %w", l.token, as, e1),
|
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lex: l,
|
|
}
|
|
return nil, false
|
|
}
|
|
|
|
zp.sub = NewZoneParser(r1, neworigin, includePath)
|
|
zp.sub.defttl, zp.sub.includeDepth, zp.sub.r = zp.defttl, zp.includeDepth+1, r1
|
|
zp.sub.SetIncludeAllowed(true)
|
|
zp.sub.SetIncludeFS(zp.fsys)
|
|
return zp.subNext()
|
|
case zExpectDirTTLBl:
|
|
if l.value != zBlank {
|
|
return zp.setParseError("no blank after $TTL-directive", l)
|
|
}
|
|
|
|
st = zExpectDirTTL
|
|
case zExpectDirTTL:
|
|
if l.value != zString {
|
|
return zp.setParseError("expecting $TTL value, not this...", l)
|
|
}
|
|
|
|
if err := slurpRemainder(zp.c); err != nil {
|
|
return zp.setParseError(err.err, err.lex)
|
|
}
|
|
|
|
ttl, ok := stringToTTL(l.token)
|
|
if !ok {
|
|
return zp.setParseError("expecting $TTL value, not this...", l)
|
|
}
|
|
|
|
zp.defttl = &ttlState{ttl, true}
|
|
|
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st = zExpectOwnerDir
|
|
case zExpectDirOriginBl:
|
|
if l.value != zBlank {
|
|
return zp.setParseError("no blank after $ORIGIN-directive", l)
|
|
}
|
|
|
|
st = zExpectDirOrigin
|
|
case zExpectDirOrigin:
|
|
if l.value != zString {
|
|
return zp.setParseError("expecting $ORIGIN value, not this...", l)
|
|
}
|
|
|
|
if err := slurpRemainder(zp.c); err != nil {
|
|
return zp.setParseError(err.err, err.lex)
|
|
}
|
|
|
|
name, ok := toAbsoluteName(l.token, zp.origin)
|
|
if !ok {
|
|
return zp.setParseError("bad origin name", l)
|
|
}
|
|
|
|
zp.origin = name
|
|
|
|
st = zExpectOwnerDir
|
|
case zExpectDirGenerateBl:
|
|
if l.value != zBlank {
|
|
return zp.setParseError("no blank after $GENERATE-directive", l)
|
|
}
|
|
|
|
st = zExpectDirGenerate
|
|
case zExpectDirGenerate:
|
|
if zp.generateDisallowed {
|
|
return zp.setParseError("nested $GENERATE directive not allowed", l)
|
|
}
|
|
if l.value != zString {
|
|
return zp.setParseError("expecting $GENERATE value, not this...", l)
|
|
}
|
|
|
|
return zp.generate(l)
|
|
case zExpectOwnerBl:
|
|
if l.value != zBlank {
|
|
return zp.setParseError("no blank after owner", l)
|
|
}
|
|
|
|
st = zExpectAny
|
|
case zExpectAny:
|
|
switch l.value {
|
|
case zRrtpe:
|
|
if zp.defttl == nil {
|
|
return zp.setParseError("missing TTL with no previous value", l)
|
|
}
|
|
|
|
h.Rrtype = l.torc
|
|
|
|
st = zExpectRdata
|
|
case zClass:
|
|
h.Class = l.torc
|
|
|
|
st = zExpectAnyNoClassBl
|
|
case zString:
|
|
ttl, ok := stringToTTL(l.token)
|
|
if !ok {
|
|
return zp.setParseError("not a TTL", l)
|
|
}
|
|
|
|
h.Ttl = ttl
|
|
|
|
if zp.defttl == nil || !zp.defttl.isByDirective {
|
|
zp.defttl = &ttlState{ttl, false}
|
|
}
|
|
|
|
st = zExpectAnyNoTTLBl
|
|
default:
|
|
return zp.setParseError("expecting RR type, TTL or class, not this...", l)
|
|
}
|
|
case zExpectAnyNoClassBl:
|
|
if l.value != zBlank {
|
|
return zp.setParseError("no blank before class", l)
|
|
}
|
|
|
|
st = zExpectAnyNoClass
|
|
case zExpectAnyNoTTLBl:
|
|
if l.value != zBlank {
|
|
return zp.setParseError("no blank before TTL", l)
|
|
}
|
|
|
|
st = zExpectAnyNoTTL
|
|
case zExpectAnyNoTTL:
|
|
switch l.value {
|
|
case zClass:
|
|
h.Class = l.torc
|
|
|
|
st = zExpectRrtypeBl
|
|
case zRrtpe:
|
|
h.Rrtype = l.torc
|
|
|
|
st = zExpectRdata
|
|
default:
|
|
return zp.setParseError("expecting RR type or class, not this...", l)
|
|
}
|
|
case zExpectAnyNoClass:
|
|
switch l.value {
|
|
case zString:
|
|
ttl, ok := stringToTTL(l.token)
|
|
if !ok {
|
|
return zp.setParseError("not a TTL", l)
|
|
}
|
|
|
|
h.Ttl = ttl
|
|
|
|
if zp.defttl == nil || !zp.defttl.isByDirective {
|
|
zp.defttl = &ttlState{ttl, false}
|
|
}
|
|
|
|
st = zExpectRrtypeBl
|
|
case zRrtpe:
|
|
h.Rrtype = l.torc
|
|
|
|
st = zExpectRdata
|
|
default:
|
|
return zp.setParseError("expecting RR type or TTL, not this...", l)
|
|
}
|
|
case zExpectRrtypeBl:
|
|
if l.value != zBlank {
|
|
return zp.setParseError("no blank before RR type", l)
|
|
}
|
|
|
|
st = zExpectRrtype
|
|
case zExpectRrtype:
|
|
if l.value != zRrtpe {
|
|
return zp.setParseError("unknown RR type", l)
|
|
}
|
|
|
|
h.Rrtype = l.torc
|
|
|
|
st = zExpectRdata
|
|
case zExpectRdata:
|
|
var (
|
|
rr RR
|
|
parseAsRFC3597 bool
|
|
)
|
|
if newFn, ok := TypeToRR[h.Rrtype]; ok {
|
|
rr = newFn()
|
|
*rr.Header() = *h
|
|
|
|
// We may be parsing a known RR type using the RFC3597 format.
|
|
// If so, we handle that here in a generic way.
|
|
//
|
|
// This is also true for PrivateRR types which will have the
|
|
// RFC3597 parsing done for them and the Unpack method called
|
|
// to populate the RR instead of simply deferring to Parse.
|
|
if zp.c.Peek().token == "\\#" {
|
|
parseAsRFC3597 = true
|
|
}
|
|
} else {
|
|
rr = &RFC3597{Hdr: *h}
|
|
}
|
|
|
|
_, isPrivate := rr.(*PrivateRR)
|
|
if !isPrivate && zp.c.Peek().token == "" {
|
|
// This is a dynamic update rr.
|
|
|
|
if err := slurpRemainder(zp.c); err != nil {
|
|
return zp.setParseError(err.err, err.lex)
|
|
}
|
|
|
|
return rr, true
|
|
} else if l.value == zNewline {
|
|
return zp.setParseError("unexpected newline", l)
|
|
}
|
|
|
|
parseAsRR := rr
|
|
if parseAsRFC3597 {
|
|
parseAsRR = &RFC3597{Hdr: *h}
|
|
}
|
|
|
|
if err := parseAsRR.parse(zp.c, zp.origin); err != nil {
|
|
// err is a concrete *ParseError without the file field set.
|
|
// The setParseError call below will construct a new
|
|
// *ParseError with file set to zp.file.
|
|
|
|
// err.lex may be nil in which case we substitute our current
|
|
// lex token.
|
|
if err.lex == (lex{}) {
|
|
return zp.setParseError(err.err, l)
|
|
}
|
|
|
|
return zp.setParseError(err.err, err.lex)
|
|
}
|
|
|
|
if parseAsRFC3597 {
|
|
err := parseAsRR.(*RFC3597).fromRFC3597(rr)
|
|
if err != nil {
|
|
return zp.setParseError(err.Error(), l)
|
|
}
|
|
}
|
|
|
|
return rr, true
|
|
}
|
|
}
|
|
|
|
// 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.
|
|
return nil, false
|
|
}
|
|
|
|
type zlexer struct {
|
|
br io.ByteReader
|
|
|
|
readErr error
|
|
|
|
line int
|
|
column int
|
|
|
|
comBuf string
|
|
comment string
|
|
|
|
l lex
|
|
cachedL *lex
|
|
|
|
brace int
|
|
quote bool
|
|
space bool
|
|
commt bool
|
|
rrtype bool
|
|
owner bool
|
|
|
|
nextL bool
|
|
|
|
eol bool // end-of-line
|
|
}
|
|
|
|
func newZLexer(r io.Reader) *zlexer {
|
|
br, ok := r.(io.ByteReader)
|
|
if !ok {
|
|
br = bufio.NewReaderSize(r, 1024)
|
|
}
|
|
|
|
return &zlexer{
|
|
br: br,
|
|
|
|
line: 1,
|
|
|
|
owner: true,
|
|
}
|
|
}
|
|
|
|
func (zl *zlexer) Err() error {
|
|
if zl.readErr == io.EOF {
|
|
return nil
|
|
}
|
|
|
|
return zl.readErr
|
|
}
|
|
|
|
// readByte returns the next byte from the input
|
|
func (zl *zlexer) readByte() (byte, bool) {
|
|
if zl.readErr != nil {
|
|
return 0, false
|
|
}
|
|
|
|
c, err := zl.br.ReadByte()
|
|
if err != nil {
|
|
zl.readErr = err
|
|
return 0, false
|
|
}
|
|
|
|
// delay the newline handling until the next token is delivered,
|
|
// fixes off-by-one errors when reporting a parse error.
|
|
if zl.eol {
|
|
zl.line++
|
|
zl.column = 0
|
|
zl.eol = false
|
|
}
|
|
|
|
if c == '\n' {
|
|
zl.eol = true
|
|
} else {
|
|
zl.column++
|
|
}
|
|
|
|
return c, true
|
|
}
|
|
|
|
func (zl *zlexer) Peek() lex {
|
|
if zl.nextL {
|
|
return zl.l
|
|
}
|
|
|
|
l, ok := zl.Next()
|
|
if !ok {
|
|
return l
|
|
}
|
|
|
|
if zl.nextL {
|
|
// Cache l. Next returns zl.cachedL then zl.l.
|
|
zl.cachedL = &l
|
|
} else {
|
|
// In this case l == zl.l, so we just tell Next to return zl.l.
|
|
zl.nextL = true
|
|
}
|
|
|
|
return l
|
|
}
|
|
|
|
func (zl *zlexer) Next() (lex, bool) {
|
|
l := &zl.l
|
|
switch {
|
|
case zl.cachedL != nil:
|
|
l, zl.cachedL = zl.cachedL, nil
|
|
return *l, true
|
|
case zl.nextL:
|
|
zl.nextL = false
|
|
return *l, true
|
|
case l.err:
|
|
// Parsing errors should be sticky.
|
|
return lex{value: zEOF}, false
|
|
}
|
|
|
|
var (
|
|
str = make([]byte, maxTok) // Hold string text
|
|
com = make([]byte, maxTok) // Hold comment text
|
|
|
|
stri int // Offset in str (0 means empty)
|
|
comi int // Offset in com (0 means empty)
|
|
|
|
escape bool
|
|
)
|
|
|
|
if zl.comBuf != "" {
|
|
comi = copy(com[:], zl.comBuf)
|
|
zl.comBuf = ""
|
|
}
|
|
|
|
zl.comment = ""
|
|
|
|
for x, ok := zl.readByte(); ok; x, ok = zl.readByte() {
|
|
l.line, l.column = zl.line, zl.column
|
|
|
|
if stri >= len(str) {
|
|
// if buffer length is insufficient, increase it.
|
|
str = append(str[:], make([]byte, maxTok)...)
|
|
}
|
|
if comi >= len(com) {
|
|
// if buffer length is insufficient, increase it.
|
|
com = append(com[:], make([]byte, maxTok)...)
|
|
}
|
|
|
|
switch x {
|
|
case ' ', '\t':
|
|
if escape || zl.quote {
|
|
// Inside quotes or escaped this is legal.
|
|
str[stri] = x
|
|
stri++
|
|
|
|
escape = false
|
|
break
|
|
}
|
|
|
|
if zl.commt {
|
|
com[comi] = x
|
|
comi++
|
|
break
|
|
}
|
|
|
|
var retL lex
|
|
if stri == 0 {
|
|
// Space directly in the beginning, handled in the grammar
|
|
} else if zl.owner {
|
|
// If we have a string and it's the first, make it an owner
|
|
l.value = zOwner
|
|
l.token = string(str[:stri])
|
|
|
|
// escape $... start with a \ not a $, so this will work
|
|
switch strings.ToUpper(l.token) {
|
|
case "$TTL":
|
|
l.value = zDirTTL
|
|
case "$ORIGIN":
|
|
l.value = zDirOrigin
|
|
case "$INCLUDE":
|
|
l.value = zDirInclude
|
|
case "$GENERATE":
|
|
l.value = zDirGenerate
|
|
}
|
|
|
|
retL = *l
|
|
} else {
|
|
l.value = zString
|
|
l.token = string(str[:stri])
|
|
|
|
if !zl.rrtype {
|
|
tokenUpper := strings.ToUpper(l.token)
|
|
if t, ok := StringToType[tokenUpper]; ok {
|
|
l.value = zRrtpe
|
|
l.torc = t
|
|
|
|
zl.rrtype = true
|
|
} else if strings.HasPrefix(tokenUpper, "TYPE") {
|
|
t, ok := typeToInt(l.token)
|
|
if !ok {
|
|
l.token = "unknown RR type"
|
|
l.err = true
|
|
return *l, true
|
|
}
|
|
|
|
l.value = zRrtpe
|
|
l.torc = t
|
|
|
|
zl.rrtype = true
|
|
}
|
|
|
|
if t, ok := StringToClass[tokenUpper]; ok {
|
|
l.value = zClass
|
|
l.torc = t
|
|
} else if strings.HasPrefix(tokenUpper, "CLASS") {
|
|
t, ok := classToInt(l.token)
|
|
if !ok {
|
|
l.token = "unknown class"
|
|
l.err = true
|
|
return *l, true
|
|
}
|
|
|
|
l.value = zClass
|
|
l.torc = t
|
|
}
|
|
}
|
|
|
|
retL = *l
|
|
}
|
|
|
|
zl.owner = false
|
|
|
|
if !zl.space {
|
|
zl.space = true
|
|
|
|
l.value = zBlank
|
|
l.token = " "
|
|
|
|
if retL == (lex{}) {
|
|
return *l, true
|
|
}
|
|
|
|
zl.nextL = true
|
|
}
|
|
|
|
if retL != (lex{}) {
|
|
return retL, true
|
|
}
|
|
case ';':
|
|
if escape || zl.quote {
|
|
// Inside quotes or escaped this is legal.
|
|
str[stri] = x
|
|
stri++
|
|
|
|
escape = false
|
|
break
|
|
}
|
|
|
|
zl.commt = true
|
|
zl.comBuf = ""
|
|
|
|
if comi > 1 {
|
|
// A newline was previously seen inside a comment that
|
|
// was inside braces and we delayed adding it until now.
|
|
com[comi] = ' ' // convert newline to space
|
|
comi++
|
|
if comi >= len(com) {
|
|
l.token = "comment length insufficient for parsing"
|
|
l.err = true
|
|
return *l, true
|
|
}
|
|
}
|
|
|
|
com[comi] = ';'
|
|
comi++
|
|
|
|
if stri > 0 {
|
|
zl.comBuf = string(com[:comi])
|
|
|
|
l.value = zString
|
|
l.token = string(str[:stri])
|
|
return *l, true
|
|
}
|
|
case '\r':
|
|
escape = false
|
|
|
|
if zl.quote {
|
|
str[stri] = x
|
|
stri++
|
|
}
|
|
|
|
// discard if outside of quotes
|
|
case '\n':
|
|
escape = false
|
|
|
|
// Escaped newline
|
|
if zl.quote {
|
|
str[stri] = x
|
|
stri++
|
|
break
|
|
}
|
|
|
|
if zl.commt {
|
|
// Reset a comment
|
|
zl.commt = false
|
|
zl.rrtype = false
|
|
|
|
// If not in a brace this ends the comment AND the RR
|
|
if zl.brace == 0 {
|
|
zl.owner = true
|
|
|
|
l.value = zNewline
|
|
l.token = "\n"
|
|
zl.comment = string(com[:comi])
|
|
return *l, true
|
|
}
|
|
|
|
zl.comBuf = string(com[:comi])
|
|
break
|
|
}
|
|
|
|
if zl.brace == 0 {
|
|
// If there is previous text, we should output it here
|
|
var retL lex
|
|
if stri != 0 {
|
|
l.value = zString
|
|
l.token = string(str[:stri])
|
|
|
|
if !zl.rrtype {
|
|
tokenUpper := strings.ToUpper(l.token)
|
|
if t, ok := StringToType[tokenUpper]; ok {
|
|
zl.rrtype = true
|
|
|
|
l.value = zRrtpe
|
|
l.torc = t
|
|
}
|
|
}
|
|
|
|
retL = *l
|
|
}
|
|
|
|
l.value = zNewline
|
|
l.token = "\n"
|
|
|
|
zl.comment = zl.comBuf
|
|
zl.comBuf = ""
|
|
zl.rrtype = false
|
|
zl.owner = true
|
|
|
|
if retL != (lex{}) {
|
|
zl.nextL = true
|
|
return retL, true
|
|
}
|
|
|
|
return *l, true
|
|
}
|
|
case '\\':
|
|
// comments do not get escaped chars, everything is copied
|
|
if zl.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 zl.commt {
|
|
com[comi] = x
|
|
comi++
|
|
break
|
|
}
|
|
|
|
if escape {
|
|
str[stri] = x
|
|
stri++
|
|
|
|
escape = false
|
|
break
|
|
}
|
|
|
|
zl.space = false
|
|
|
|
// send previous gathered text and the quote
|
|
var retL lex
|
|
if stri != 0 {
|
|
l.value = zString
|
|
l.token = string(str[:stri])
|
|
|
|
retL = *l
|
|
}
|
|
|
|
// send quote itself as separate token
|
|
l.value = zQuote
|
|
l.token = "\""
|
|
|
|
zl.quote = !zl.quote
|
|
|
|
if retL != (lex{}) {
|
|
zl.nextL = true
|
|
return retL, true
|
|
}
|
|
|
|
return *l, true
|
|
case '(', ')':
|
|
if zl.commt {
|
|
com[comi] = x
|
|
comi++
|
|
break
|
|
}
|
|
|
|
if escape || zl.quote {
|
|
// Inside quotes or escaped this is legal.
|
|
str[stri] = x
|
|
stri++
|
|
|
|
escape = false
|
|
break
|
|
}
|
|
|
|
switch x {
|
|
case ')':
|
|
zl.brace--
|
|
|
|
if zl.brace < 0 {
|
|
l.token = "extra closing brace"
|
|
l.err = true
|
|
return *l, true
|
|
}
|
|
case '(':
|
|
zl.brace++
|
|
}
|
|
default:
|
|
escape = false
|
|
|
|
if zl.commt {
|
|
com[comi] = x
|
|
comi++
|
|
break
|
|
}
|
|
|
|
str[stri] = x
|
|
stri++
|
|
|
|
zl.space = false
|
|
}
|
|
}
|
|
|
|
if zl.readErr != nil && zl.readErr != io.EOF {
|
|
// Don't return any tokens after a read error occurs.
|
|
return lex{value: zEOF}, false
|
|
}
|
|
|
|
var retL lex
|
|
if stri > 0 {
|
|
// Send remainder of str
|
|
l.value = zString
|
|
l.token = string(str[:stri])
|
|
retL = *l
|
|
|
|
if comi <= 0 {
|
|
return retL, true
|
|
}
|
|
}
|
|
|
|
if comi > 0 {
|
|
// Send remainder of com
|
|
l.value = zNewline
|
|
l.token = "\n"
|
|
zl.comment = string(com[:comi])
|
|
|
|
if retL != (lex{}) {
|
|
zl.nextL = true
|
|
return retL, true
|
|
}
|
|
|
|
return *l, true
|
|
}
|
|
|
|
if zl.brace != 0 {
|
|
l.token = "unbalanced brace"
|
|
l.err = true
|
|
return *l, true
|
|
}
|
|
|
|
return lex{value: zEOF}, false
|
|
}
|
|
|
|
func (zl *zlexer) Comment() string {
|
|
if zl.l.err {
|
|
return ""
|
|
}
|
|
|
|
return zl.comment
|
|
}
|
|
|
|
// 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) {
|
|
var s, i uint32
|
|
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]
|
|
}
|
|
|
|
var (
|
|
meters, cmeters, val int
|
|
err error
|
|
)
|
|
mStr, cmStr, hasCM := strings.Cut(token, ".")
|
|
if hasCM {
|
|
// There's no point in having more than 2 digits in this part, and would rather make the implementation complicated ('123' should be treated as '12').
|
|
// So we simply reject it.
|
|
// We also make sure the first character is a digit to reject '+-' signs.
|
|
cmeters, err = strconv.Atoi(cmStr)
|
|
if err != nil || len(cmStr) > 2 || cmStr[0] < '0' || cmStr[0] > '9' {
|
|
return
|
|
}
|
|
if len(cmStr) == 1 {
|
|
// 'nn.1' must be treated as 'nn-meters and 10cm, not 1cm.
|
|
cmeters *= 10
|
|
}
|
|
}
|
|
// This slightly ugly condition will allow omitting the 'meter' part, like .01 (meaning 0.01m = 1cm).
|
|
if !hasCM || mStr != "" {
|
|
meters, err = strconv.Atoi(mStr)
|
|
// RFC1876 states the max value is 90000000.00. The latter two conditions enforce it.
|
|
if err != nil || mStr[0] < '0' || mStr[0] > '9' || meters > 90000000 || (meters == 90000000 && cmeters != 0) {
|
|
return
|
|
}
|
|
}
|
|
|
|
if meters > 0 {
|
|
e = 2
|
|
val = meters
|
|
} else {
|
|
e = 0
|
|
val = cmeters
|
|
}
|
|
for val >= 10 {
|
|
e++
|
|
val /= 10
|
|
}
|
|
return e, uint8(val), true
|
|
}
|
|
|
|
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 IsFqdn(name) {
|
|
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) {
|
|
if latitude > 90*1000*60*60 {
|
|
return latitude, false
|
|
}
|
|
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) {
|
|
if longitude > 180*1000*60*60 {
|
|
return longitude, false
|
|
}
|
|
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"
|
|
func slurpRemainder(c *zlexer) *ParseError {
|
|
l, _ := c.Next()
|
|
switch l.value {
|
|
case zBlank:
|
|
l, _ = c.Next()
|
|
if l.value != zNewline && l.value != zEOF {
|
|
return &ParseError{err: "garbage after rdata", lex: l}
|
|
}
|
|
case zNewline:
|
|
case zEOF:
|
|
default:
|
|
return &ParseError{err: "garbage after rdata", lex: l}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// 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{file: l.token, err: "bad NID/L64 NodeID/Locator64", lex: l}
|
|
}
|
|
// There must be three colons at fixes positions, if not its a parse error
|
|
if l.token[4] != ':' && l.token[9] != ':' && l.token[14] != ':' {
|
|
return 0, &ParseError{file: l.token, err: "bad NID/L64 NodeID/Locator64", lex: 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{file: l.token, err: "bad NID/L64 NodeID/Locator64", lex: l}
|
|
}
|
|
return u, nil
|
|
}
|