125 lines
2.9 KiB
Plaintext
125 lines
2.9 KiB
Plaintext
// Copyright Miek Gieben 2011
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// Heavily influenced by the zone-parser from NSD
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%{
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package parse
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import (
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"fmt"
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)
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// A yacc parser for DNS Resource Records contained in strings
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%}
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%union {
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val string
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rrtype uint16
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class uint16
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ttl uint16
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}
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/*
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* Types known to package dns
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*/
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%token <rrtype> YA YNS
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/*
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* Other elements of the Resource Records
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*/
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%token <ttl> TTL
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%token <class> CLASS
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%token <val> VAL
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%%
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rr: name TTL CLASS rrtype
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{
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};
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name: label
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| name '.' label
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label: VAL
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rrtype:
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/* All supported RR types */
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YA
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| YNS
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%%
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type DnsLex int
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func (DnsLex) Lex(lval *yySymType) int {
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// yylval.rrtype = Str_rr($XX) //give back TypeA, TypeNS
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// return Y_A this should be the token, another map?
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//func scan(s string) (string, int) {
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if len(s) == 0 {
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println("a bit short")
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}
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raw := []byte(s)
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chunk := ""
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off := 0
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brace := 0
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redo:
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for off < len(raw) {
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c := raw[off]
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// println(c, string(c))
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switch c {
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case '\n':
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// normal case??
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if brace > 0 {
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off++
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continue
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}
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case '.':
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// println("off", off)
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if off == 0 {
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print("DOT")
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return ".", off + 1
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} else {
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return chunk, off
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}
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case ' ','\t':
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if brace != 0 {
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off++
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continue
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}
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// eat whitespace
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// Look at next char
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if raw[off+1] == ' ' {
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off++
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continue
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} else {
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// if chunk is empty, we have skipped whitespace, and seen nothing
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if len(chunk) == 0 {
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off++
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goto redo
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}
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print("VAL ")
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return chunk, off
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}
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case '(':
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brace++
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off++
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continue
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case ')':
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brace--
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if brace < 0 {
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println("syntax error")
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}
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off++
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continue
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}
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if c == ' ' { println("adding space") }
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if c == '\t' { println("adding tab") }
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chunk += string(c)
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off++
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}
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print("VAL ")
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return chunk, off
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}
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