break CNAME

src/main.rs

@@ -74,16 +74,16 @@ impl<'a> DNS<'a> {
  self.value[self.offset + 6] as u16 * 256 + self.value[self.offset + 7] as u16;
  count
  }
- // pub fn nscount(&self) -> u16 {
- //  let count: u16 =
- //  self.value[self.offset + 8] as u16 * 256 + self.value[self.offset + 9] as u16;
- //  count
- // }
- // pub fn arcount(&self) -> u16 {
- //  let count: u16 =
- //  self.value[self.offset + 10] as u16 * 256 + self.value[self.offset + 11] as u16;
- //  count
- // }
+ pub fn nscount(&self) -> u16 {
+ let count: u16 =
+ self.value[self.offset + 8] as u16 * 256 + self.value[self.offset + 9] as u16;
+ count
+ }
+ pub fn arcount(&self) -> u16 {
+ let count: u16 =
+ self.value[self.offset + 10] as u16 * 256 + self.value[self.offset + 11] as u16;
+ count
+ }
  pub fn question_list(&self) -> Vec<(String, &'static str)> {
  let mut vec = Vec::with_capacity(1);
  let mut j = 12;
@@ -167,19 +167,35 @@ impl<'a> DNS<'a> {
  // 若是真正的数据，会以0x00结尾；若是指针，指针占2个字节，第一个字节的高2位为11。
  for _ in 0..self.ancount() {
  if self.value[n] & 0b_1100_0000 == 0b_1100_0000 {
- let pointer =
- (self.value[n] & 0b_0011_1111) as u16 * 256 + self.value[n + 1] as u16;
- let rdlength = self.value[n + pointer as usize - 2] as u16 * 256
- + self.value[n + pointer as usize - 1] as u16; // RDLENGTH
- vec.push(b2a(
- &self.value[n + pointer as usize..n + pointer as usize + rdlength as usize]
- ));
- n += (pointer + rdlength) as usize;
+ let qtype = self.value[n + 2] as u16 * 256 + self.value[n + 3] as u16;
+ match qtype {
+ 0x0001 | 0x001c => {
+ let pointer =
+ (self.value[n] & 0b_0011_1111) as u16 * 256 + self.value[n + 1] as u16;
+ let rdlength = self.value[n + pointer as usize - 2] as u16 * 256
+ + self.value[n + pointer as usize - 1] as u16; // RDLENGTH
+ vec.push(b2a(
+ &self.value[n + pointer as usize..n + pointer as usize + rdlength as usize]
+ ));
+ n += (pointer + rdlength) as usize;
+ },
+ 0x0005 => {
+ vec.push("CNAME".to_string());
+ break;
+ },
+ _ => vec.push("Unknown QTYPE".to_string()),
+ }
+ } else { // not pointer
+ vec.push("Not Pointer".to_string());
+ break;
  }
  }
  vec
  }
  pub fn answer(&self) -> String {
+ if self.ancount() == 0 {
+ return format!("Authority: {}, Additional: {}", self.nscount(), self.arcount());
+ }
  let mut str = String::with_capacity(1024);
  for answer in self.answer_list() {
  str.push_str(&format!("{}, ", answer));