Code for parsing headers added.

src/main.rs

@@ -0,0 +1,96 @@
+use flume::{Receiver, Sender};
+use std::net::UdpSocket;
+use std::thread::{self, JoinHandle};
+use std::convert::TryInto;
+
+mod proto;
+use proto::{DNSHeader, DNSOpCode, DNSRCode};
+
+
+fn listen() -> (JoinHandle<()>, Sender<Vec<u8>>, Receiver<Vec<u8>>) {
+    let (tx, rx) = flume::unbounded();
+
+    let tx_clone = tx.clone();
+    let rx_clone = rx.clone();
+
+    (
+        thread::spawn(move || {
+            let socket = UdpSocket::bind("127.0.0.1:13337").unwrap();
+
+            let mut buf = [0; 512];
+
+            loop {
+                let (len, _src) = socket.recv_from(&mut buf).unwrap();
+
+                let buf = &mut buf[..len];
+                tx.send(Vec::from(buf)).unwrap();
+            }
+        }),
+        tx_clone,
+        rx_clone,
+    )
+}
+
+
+const QR_MASK:u16 = 0x0001;
+const OPCODE_MASK:u16 = 0x000e;
+const AA_MASK:u16 = 0x0020;
+const TC_MASK:u16 = 0x0040;
+const RD_MASK:u16 = 0x0080;
+const RA_MASK:u16 = 0x0100;
+const AD_MASK:u16 = 0x0400;
+const CD_MASK:u16 = 0x0800;
+const RCODE_MASK:u16 = 0xf000;
+
+const OPCODE_OFFSET:u16 = 1;
+const RCODE_OFFSET:u16 = 11;
+
+fn main() {
+    let (thread_udp, _thread_udp_tx, thread_udp_rx) = listen();
+
+    for msg in thread_udp_rx.iter() {
+        println!("{:?}", msg);
+
+        // TODO: check for enough data in msg
+
+        let id = u16::from_be_bytes((&msg[..2]).try_into().unwrap());
+        
+        let flags = u16::from_be_bytes((&msg[2..4]).try_into().unwrap());
+        let qr = (flags & QR_MASK) != 0;
+        let opcode:DNSOpCode = DNSOpCode::from((flags & OPCODE_MASK) >> OPCODE_OFFSET);
+        let authoritative_answer = (flags & AA_MASK) != 0;
+        let truncated = (flags & TC_MASK) != 0;
+        let recursion_desired= (flags & RD_MASK) != 0;
+        let recursion_available = (flags & RA_MASK) != 0;
+        let authentic_data = (flags & AD_MASK) != 0;
+        let checking_disabled = (flags & CD_MASK) != 0;
+        let response_code: DNSRCode = DNSRCode::from((flags & RCODE_MASK) >> RCODE_OFFSET);
+
+        let qd_zo_count = u16::from_be_bytes((&msg[4..6]).try_into().unwrap());
+        let an_pr_count = u16::from_be_bytes((&msg[6..8]).try_into().unwrap());
+        let ns_up_count = u16::from_be_bytes((&msg[8..10]).try_into().unwrap());
+        let ar_count = u16::from_be_bytes((&msg[10..12]).try_into().unwrap());
+
+        let hdr_struct = DNSHeader {
+            id,
+            qr,
+            opcode,
+            authoritative_answer,
+            truncated,
+            recursion_desired,
+            recursion_available,
+            authentic_data,
+            checking_disabled,
+            response_code,
+            qd_zo_count,
+            an_pr_count,
+            ns_up_count,
+            ar_count,
+        };
+
+        dbg!(hdr_struct);
+        
+    }
+
+    let _ = thread_udp.join();
+}