From 5bb4bbf022475f636fa70d9849abffe50013d2cd Mon Sep 17 00:00:00 2001
From: ssrlive <30760636+ssrlive@users.noreply.github.com>
Date: Sun, 6 Aug 2023 21:36:00 +0800
Subject: [PATCH] remove raw dns parse code

---
 src/virtdns.rs | 140 -------------------------------------------------
 1 file changed, 140 deletions(-)

diff --git a/src/virtdns.rs b/src/virtdns.rs
index 6f8949a..9e13e05 100644
--- a/src/virtdns.rs
+++ b/src/virtdns.rs
@@ -44,7 +44,6 @@ impl VirtualDns {
         VirtualDns::default()
     }
 
-    // /*
     pub fn receive_query(&mut self, data: &[u8]) -> Result<Vec<u8>> {
         use crate::dns;
         let message = dns::parse_data_to_dns_message(data, false)?;
@@ -53,105 +52,7 @@ impl VirtualDns {
         let message = dns::build_dns_response(message, &qname, ip, 5)?;
         Ok(message.to_vec()?)
     }
-    // */
-    /*
-    pub fn receive_query(&mut self, data: &[u8]) -> Result<Vec<u8>> {
-        #[derive(Eq, PartialEq, Debug)]
-        #[allow(dead_code, clippy::upper_case_acronyms)]
-        enum DnsRecordType {
-            A = 1,
-            AAAA = 28,
-        }
 
-        #[derive(Eq, PartialEq, Debug)]
-        #[allow(dead_code)]
-        enum DnsClass {
-            IN = 1,
-        }
-
-        if data.len() < 17 {
-            return Err("Invalid DNS query".into());
-        }
-        // bit 1: Message is a query (0)
-        // bits 2 - 5: Standard query opcode (0)
-        // bit 6: Unused
-        // bit 7: Message is not truncated (0)
-        // bit 8: Recursion desired (1)
-        let is_supported_query = (data[2] & 0b11111011) == 0b00000001;
-        let num_queries = u16::from_be_bytes(data[4..6].try_into()?);
-        if !is_supported_query || num_queries != 1 {
-            return Err("Invalid DNS query".into());
-        }
-
-        let (qname, offset) = VirtualDns::parse_qname(data, 12).ok_or("parse_qname")?;
-        if offset + 3 >= data.len() {
-            return Err("Invalid DNS query".into());
-        }
-        let qtype = u16::from_be_bytes(data[offset..offset + 2].try_into()?);
-        let qclass = u16::from_be_bytes(data[offset + 2..offset + 4].try_into()?);
-
-        if qtype != DnsRecordType::A as u16 && qtype != DnsRecordType::AAAA as u16
-            || qclass != DnsClass::IN as u16
-        {
-            return Err("Invalid DNS query".into());
-        }
-
-        if qtype == DnsRecordType::A as u16 {
-            log::info!("DNS query: {}", qname);
-        }
-
-        let mut response = Vec::<u8>::new();
-        response.extend(&data[0..offset + 4]);
-        response[2] |= 0x80; // Message is a response
-        response[3] |= 0x80; // Recursion available
-
-        // Record count of the answer section:
-        // We only send an answer record for A queries, assuming that IPv4 is supported everywhere.
-        // This way, we do not have to handle two IP spaces for the virtual DNS feature.
-        response[6] = 0;
-        response[7] = if qtype == DnsRecordType::A as u16 {
-            1
-        } else {
-            0
-        };
-
-        // Zero count of other sections:
-        // authority section
-        response[8] = 0;
-        response[9] = 0;
-
-        const DNS_TTL: u8 = 30; // TTL in DNS replies in seconds
-
-        // additional section
-        response[10] = 0;
-        response[11] = 0;
-        if qtype == DnsRecordType::A as u16 {
-            if let Ok(ip) = self.allocate_ip(qname) {
-                response.extend(&[
-                    0xc0, 0x0c, // Question name pointer
-                    0, 1, // Record type: A
-                    0, 1, // Class: IN
-                    0, 0, 0, DNS_TTL, // TTL
-                    0, 4, // Data length: 4 bytes
-                ]);
-                match ip {
-                    IpAddr::V4(ip) => response.extend(ip.octets().as_ref()),
-                    IpAddr::V6(ip) => response.extend(ip.octets().as_ref()),
-                };
-            } else {
-                log::error!("Virtual IP space for DNS exhausted");
-                response[7] = 0; // No answers
-
-                // Set rcode to SERVFAIL
-                response[3] &= 0xf0;
-                response[3] |= 2;
-            }
-        } else {
-            response[7] = 0; // No answers
-        }
-        Ok(response)
-    }
-    // */
     fn increment_ip(addr: IpAddr) -> Result<IpAddr> {
         let mut ip_bytes = match addr as IpAddr {
             IpAddr::V4(ip) => Vec::<u8>::from(ip.octets()),
@@ -238,45 +139,4 @@ impl VirtualDns {
             }
         }
     }
-
-    /*
-    /// Parse a non-root DNS qname at a specific offset and return the name along with its size.
-    /// DNS packet parsing should be continued after the name.
-    fn parse_qname(data: &[u8], mut offset: usize) -> Option<(String, usize)> {
-        // Since we only parse qnames and qnames can't point anywhere,
-        // we do not support pointers. (0xC0 is a bitmask for pointer detection.)
-        let label_type = data[offset] & 0xC0;
-        if label_type != 0x00 {
-            return None;
-        }
-
-        let mut qname = String::from("");
-        loop {
-            if offset >= data.len() {
-                return None;
-            }
-            let label_len = data[offset];
-            if label_len == 0 {
-                if qname.is_empty() {
-                    return None;
-                }
-                offset += 1;
-                break;
-            }
-            if !qname.is_empty() {
-                qname.push('.');
-            }
-            for _ in 0..label_len {
-                offset += 1;
-                if offset >= data.len() {
-                    return None;
-                }
-                qname.push(data[offset] as char);
-            }
-            offset += 1;
-        }
-
-        Some((qname, offset))
-    }
-    // */
 }