feat(c3): add time limit

solutions/3.py

@@ -1,5 +1,6 @@
 from io import TextIOWrapper
 import socket
+import time
 
 REMOTE = "127.0.0.1"
 PORT = 1337
@@ -50,10 +51,15 @@ def main() -> int:
             print(f"# We won: '{response}'")
             break
 
+        elif "slow" in response:
+            print(f"# We are too slow, it's futile")
+            break
+
         else:
             print(f"! unknown response: '{response}'")
             s.close()
             return 1
+
     s.close()
     return 0
 

src/challenge/c3.rs

@@ -8,6 +8,7 @@ use rand::distributions::{Distribution, Standard};
 use rand::{random, Rng};
 use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader};
 use tokio::net::{TcpListener, TcpStream};
+use tokio::time::Instant;
 
 use super::Challenge;
 use crate::config::Config;
@@ -90,11 +91,22 @@ impl C3 {
         let (stream_read, mut stream_write) = stream.split();
         let mut rdbuf = BufReader::new(stream_read);
 
+        let mut last_reset = Instant::now();
+
         loop {
             if correct >= NEEDED_CORRECT {
                 Self::win(vault, &mut stream, &addr).await?;
                 break;
             }
+            if last_reset.elapsed().as_millis() > NEEDED_CORRECT as u128 * 200 {
+                correct = 0;
+                debug!("{addr} was too slow, resetting");
+                stream_write
+                    .write_all("You're too slow!\n".to_string().as_bytes())
+                    .await?;
+                last_reset = Instant::now();
+                continue;
+            }
             let (question, solution) = Self::mk_question();
             debug!("sending question to {addr}: '{question}'");
             stream_write.write_all((question + "\n").as_bytes()).await?;
@@ -112,6 +124,7 @@ impl C3 {
                     .write_all("wrong!\n".to_string().as_bytes())
                     .await?;
                 correct = 0;
+                last_reset = Instant::now();
             }
             buf.clear()
         }