diff options
Diffstat (limited to 'vendor/github.com/miekg/dns/generate.go')
| -rw-r--r-- | vendor/github.com/miekg/dns/generate.go | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/vendor/github.com/miekg/dns/generate.go b/vendor/github.com/miekg/dns/generate.go new file mode 100644 index 000000000..e4481a4b0 --- /dev/null +++ b/vendor/github.com/miekg/dns/generate.go @@ -0,0 +1,159 @@ +package dns + +import ( + "bytes" + "errors" + "fmt" + "strconv" + "strings" +) + +// Parse the $GENERATE statement as used in BIND9 zones. +// See http://www.zytrax.com/books/dns/ch8/generate.html for instance. +// We are called after '$GENERATE '. After which we expect: +// * the range (12-24/2) +// * lhs (ownername) +// * [[ttl][class]] +// * type +// * rhs (rdata) +// But we are lazy here, only the range is parsed *all* occurrences +// of $ after that are interpreted. +// Any error are returned as a string value, the empty string signals +// "no error". +func generate(l lex, c chan lex, t chan *Token, o string) string { + step := 1 + if i := strings.IndexAny(l.token, "/"); i != -1 { + if i+1 == len(l.token) { + return "bad step in $GENERATE range" + } + if s, err := strconv.Atoi(l.token[i+1:]); err == nil { + if s < 0 { + return "bad step in $GENERATE range" + } + step = s + } else { + return "bad step in $GENERATE range" + } + l.token = l.token[:i] + } + sx := strings.SplitN(l.token, "-", 2) + if len(sx) != 2 { + return "bad start-stop in $GENERATE range" + } + start, err := strconv.Atoi(sx[0]) + if err != nil { + return "bad start in $GENERATE range" + } + end, err := strconv.Atoi(sx[1]) + if err != nil { + return "bad stop in $GENERATE range" + } + if end < 0 || start < 0 || end < start { + return "bad range in $GENERATE range" + } + + <-c // _BLANK + // Create a complete new string, which we then parse again. + s := "" +BuildRR: + l = <-c + if l.value != zNewline && l.value != zEOF { + s += l.token + goto BuildRR + } + for i := start; i <= end; i += step { + var ( + escape bool + dom bytes.Buffer + mod string + err error + offset int + ) + + for j := 0; j < len(s); j++ { // No 'range' because we need to jump around + switch s[j] { + case '\\': + if escape { + dom.WriteByte('\\') + escape = false + continue + } + escape = true + case '$': + mod = "%d" + offset = 0 + if escape { + dom.WriteByte('$') + escape = false + continue + } + escape = false + if j+1 >= len(s) { // End of the string + dom.WriteString(fmt.Sprintf(mod, i+offset)) + continue + } else { + if s[j+1] == '$' { + dom.WriteByte('$') + j++ + continue + } + } + // Search for { and } + if s[j+1] == '{' { // Modifier block + sep := strings.Index(s[j+2:], "}") + if sep == -1 { + return "bad modifier in $GENERATE" + } + mod, offset, err = modToPrintf(s[j+2 : j+2+sep]) + if err != nil { + return err.Error() + } + j += 2 + sep // Jump to it + } + dom.WriteString(fmt.Sprintf(mod, i+offset)) + default: + if escape { // Pretty useless here + escape = false + continue + } + dom.WriteByte(s[j]) + } + } + // Re-parse the RR and send it on the current channel t + rx, err := NewRR("$ORIGIN " + o + "\n" + dom.String()) + if err != nil { + return err.Error() + } + t <- &Token{RR: rx} + // Its more efficient to first built the rrlist and then parse it in + // one go! But is this a problem? + } + return "" +} + +// Convert a $GENERATE modifier 0,0,d to something Printf can deal with. +func modToPrintf(s string) (string, int, error) { + xs := strings.SplitN(s, ",", 3) + if len(xs) != 3 { + return "", 0, errors.New("bad modifier in $GENERATE") + } + // xs[0] is offset, xs[1] is width, xs[2] is base + if xs[2] != "o" && xs[2] != "d" && xs[2] != "x" && xs[2] != "X" { + return "", 0, errors.New("bad base in $GENERATE") + } + offset, err := strconv.Atoi(xs[0]) + if err != nil || offset > 255 { + return "", 0, errors.New("bad offset in $GENERATE") + } + width, err := strconv.Atoi(xs[1]) + if err != nil || width > 255 { + return "", offset, errors.New("bad width in $GENERATE") + } + switch { + case width < 0: + return "", offset, errors.New("bad width in $GENERATE") + case width == 0: + return "%" + xs[1] + xs[2], offset, nil + } + return "%0" + xs[1] + xs[2], offset, nil +} |