Byte parser for RR

src/main.rs

@@ -22,7 +22,7 @@ async fn create_query(message: Message) -> Message {
         class: Class::IN,
         ttl: 4096,
         rdlength: ip.len() as u16,
-        rdata: ip,
+        rdata: vec![1,2,3,4],
     };
 
     response.header.flags |= 0b1000010110000000;
@@ -46,7 +46,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
             tokio::spawn(async move {
                 let response = create_query(message).await;
                 println!("{:?}",response);
-                let vec = Message::to_bytes(&response);
+                let vec = Message::to_bytes(response);
                 let decoded = Message::from_bytes(vec.as_slice());
                 println!("{:?}",decoded);
                 let _ = socket.send_to(vec.as_slice(),addr).await;

src/parser.rs

@@ -2,7 +2,7 @@ use std::{mem::size_of, vec};
 
 use crate::{
     errors::ParseError,
-    structs::{Class, Header, Message, Question, Type, RR},
+    structs::{Class, Header, LabelString, Message, Question, Type, RR},
 };
 
 type Result<T> = std::result::Result<T, ParseError>;
@@ -33,7 +33,7 @@ pub trait FromBytes {
     fn from_bytes(bytes: &[u8]) -> Result<Self>
     where
         Self: Sized;
-    fn to_bytes(s: &Self) -> Vec<u8>
+    fn to_bytes(s: Self) -> Vec<u8>
     where
         Self: Sized;
 }
@@ -57,7 +57,7 @@ impl FromBytes for Header {
         }
     }
 
-    fn to_bytes(header: &Self) -> Vec<u8> {
+    fn to_bytes(header: Self) -> Vec<u8> {
         let mut result: [u8; size_of::<Header>()] = [0; size_of::<Header>()];
 
         result[0..2].copy_from_slice(&u16::to_be_bytes(header.id));
@@ -71,6 +71,33 @@ impl FromBytes for Header {
     }
 }
 
+impl FromBytes for LabelString {
+    fn from_bytes(bytes: &[u8]) -> Result<Self> {
+        let mut i = 0;
+        let mut qname = vec![];
+
+        // Parse qname labels
+        while bytes[i] != 0 && bytes[i] as usize + i < bytes.len() {
+            qname
+                .push(String::from_utf8(bytes[i + 1..bytes[i] as usize + 1 + i].to_vec()).unwrap());
+            i += bytes[i] as usize + 1;
+        }
+
+        i += 1;
+        Ok((qname, i))
+    }
+
+    fn to_bytes((name, _): Self) -> Vec<u8> {
+        let mut result: Vec<u8> = vec![];
+        for label in name {
+            result.push(label.len() as u8);
+            result.extend(label.as_bytes());
+        }
+        result.push(0);
+        result
+    }
+}
+
 impl FromBytes for Question {
     fn from_bytes(bytes: &[u8]) -> Result<Self> {
         // 16 for length octet +  zero length octet
@@ -80,17 +107,7 @@ impl FromBytes for Question {
                 message: String::from("len of bytes smaller then minimum size"),
             })
         } else {
-            let mut qname = vec![];
-            let mut i = 0;
-
-            // Parse qname labels
-            while bytes[i] != 0 && bytes[i] as usize + i < bytes.len() {
-                qname.push(
-                    String::from_utf8(bytes[i + 1..bytes[i] as usize + 1 + i].to_vec()).unwrap(),
-                );
-                i += bytes[i] as usize + 1;
-            }
-            i += 1;
+            let (qname, i) = LabelString::from_bytes(bytes)?;
 
             if bytes.len() - i < size_of::<Class>() + size_of::<Type>() {
                 Err(ParseError {
@@ -122,13 +139,8 @@ impl FromBytes for Question {
         }
     }
 
-    fn to_bytes(question: &Self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        for label in &question.qname {
-            result.push(label.len() as u8);
-            result.extend(label.as_bytes());
-        }
-        result.push(0);
+    fn to_bytes(question: Self) -> Vec<u8> {
+        let mut result = LabelString::to_bytes((question.qname, 0));
         result.extend(u16::to_be_bytes(question.qtype.to_owned() as u16));
         result.extend(u16::to_be_bytes(question.qclass.to_owned() as u16));
         result
@@ -136,28 +148,55 @@ impl FromBytes for Question {
 }
 
 impl FromBytes for RR {
-    fn from_bytes(bytes: &[u8]) -> Result<Self>
-    where
-        Self: Sized,
-    {
-        todo!()
+    fn from_bytes(bytes: &[u8]) -> Result<Self> {
+        let (name, i) = LabelString::from_bytes(bytes)?;
+        if bytes.len() - i < size_of::<Type>() + size_of::<Class>() + 6 {
+            Err(ParseError {
+                object: String::from("RR"),
+                message: String::from("len of rest of bytes smaller then minimum size"),
+            })
+        } else {
+            let _type = Type::try_from(u16::from_be_bytes(bytes[i..i + 2].try_into().unwrap()))
+                .map_err(|_| ParseError {
+                    object: String::from("Type"),
+                    message: String::from("invalid"),
+                })?;
+
+            let class =
+                Class::try_from(u16::from_be_bytes(bytes[i + 2..i + 4].try_into().unwrap()))
+                    .map_err(|_| ParseError {
+                        object: String::from("Class"),
+                        message: String::from("invalid"),
+                    })?;
+
+            let ttl = i32::from_be_bytes(bytes[i + 4..i + 8].try_into().unwrap());
+            let rdlength = u16::from_be_bytes(bytes[i + 8..i + 10].try_into().unwrap());
+
+            if bytes.len() - i - 10 != rdlength as usize {
+                Err(ParseError {
+                    object: String::from("RR"),
+                    message: String::from("len of rest of bytes not equal to rdlength"),
+                })
+            } else {
+                Ok(RR {
+                    name,
+                    _type,
+                    class,
+                    ttl,
+                    rdlength,
+                    rdata: bytes[i + 10..].to_vec(),
+                })
+            }
+        }
     }
 
-    fn to_bytes(rr: &Self) -> Vec<u8> {
-        let mut result = vec![];
-        for label in &rr.name {
-            result.push(label.len() as u8);
-            result.extend(label.as_bytes());
-        }
-        result.push(0);
+    fn to_bytes(rr: Self) -> Vec<u8> {
+        let mut result = LabelString::to_bytes((rr.name, 0));
         result.extend(u16::to_be_bytes(rr._type.to_owned() as u16));
         result.extend(u16::to_be_bytes(rr.class.to_owned() as u16));
         result.extend(i32::to_be_bytes(rr.ttl.to_owned()));
         result.extend(u16::to_be_bytes(4 as u16));
-        result.push(93);
-        result.push(184);
-        result.push(216);
-        result.push(34);
+        result.extend(rr.rdata);
         result
     }
 }
@@ -175,18 +214,18 @@ impl FromBytes for Message {
         })
     }
 
-    fn to_bytes(message: &Self) -> Vec<u8> {
+    fn to_bytes(message: Self) -> Vec<u8> {
         let mut result = vec![];
-        result.extend(Header::to_bytes(&message.header));
-        result.extend(Question::to_bytes(&message.question));
+        result.extend(Header::to_bytes(message.header));
+        result.extend(Question::to_bytes(message.question));
         if message.answer.is_some() {
-            result.extend(RR::to_bytes(&message.answer.clone().unwrap()));
+            result.extend(RR::to_bytes(message.answer.unwrap()));
         }
         if message.authority.is_some() {
-            result.extend(RR::to_bytes(&message.authority.clone().unwrap()));
+            result.extend(RR::to_bytes(message.authority.unwrap()));
         }
         if message.additional.is_some() {
-            result.extend(RR::to_bytes(&message.additional.clone().unwrap()));
+            result.extend(RR::to_bytes(message.additional.unwrap()));
         }
         result
     }

src/structs.rs

@@ -43,9 +43,11 @@ pub struct RR {
     pub class: Class,
     pub ttl: i32,
     pub rdlength: u16,
-    pub rdata: String,
+    pub rdata: Vec<u8>,
 }
 
+pub type LabelString = (Vec<String>,usize);
+
 #[derive(Debug)]
 pub struct Response {
     field: Type,