Explain usage in README

Cargo.lock

@@ -75,6 +75,12 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "anyhow"
+version = "1.0.86"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b3d1d046238990b9cf5bcde22a3fb3584ee5cf65fb2765f454ed428c7a0063da"
+
 [[package]]
 name = "async-trait"
 version = "0.1.81"
@@ -205,10 +211,13 @@ checksum = "a7993efb860416547839c115490d4951c6d0f8ec04a3594d9dd99d50ed7ec170"
 name = "dhcpv6stateless"
 version = "0.1.0"
 dependencies = [
+ "anyhow",
  "clap",
  "dhcproto",
+ "env_logger",
  "hex",
  "ipnetwork",
+ "log",
  "pnet",
  "tokio",
 ]
@@ -225,6 +234,29 @@ dependencies = [
  "syn 1.0.109",
 ]
 
+[[package]]
+name = "env_filter"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4f2c92ceda6ceec50f43169f9ee8424fe2db276791afde7b2cd8bc084cb376ab"
+dependencies = [
+ "log",
+ "regex",
+]
+
+[[package]]
+name = "env_logger"
+version = "0.11.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e13fa619b91fb2381732789fc5de83b45675e882f66623b7d8cb4f643017018d"
+dependencies = [
+ "anstream",
+ "anstyle",
+ "env_filter",
+ "humantime",
+ "log",
+]
+
 [[package]]
 name = "form_urlencoded"
 version = "1.2.1"
@@ -321,6 +353,12 @@ version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
 
+[[package]]
+name = "humantime"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9a3a5bfb195931eeb336b2a7b4d761daec841b97f947d34394601737a7bba5e4"
+
 [[package]]
 name = "idna"
 version = "0.2.3"
@@ -375,6 +413,12 @@ version = "0.2.158"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d8adc4bb1803a324070e64a98ae98f38934d91957a99cfb3a43dcbc01bc56439"
 
+[[package]]
+name = "log"
+version = "0.4.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a7a70ba024b9dc04c27ea2f0c0548feb474ec5c54bba33a7f72f873a39d07b24"
+
 [[package]]
 name = "matches"
 version = "0.1.10"

Cargo.toml

@@ -4,9 +4,12 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+anyhow = "1.0.86"
 clap = { version = "4.5.16", features = ["derive"] }
 dhcproto = "0.12.0"
+env_logger = "0.11.5"
 hex = "0.4.3"
 ipnetwork = "0.20.0"
+log = "0.4.22"
 pnet = "0.35.0"
 tokio = { version = "1.39.3", features = ["macros", "net", "rt-multi-thread"] }

README.md

@@ -2,6 +2,18 @@
 
 This -thing- is doing a DHCPv6 INFORMATION-REQUEST, waits for a response and displays it.
 
+## Usage
+
+Pass the interface name as the first parameter:
+
+```
+dhcpv6stateless wlp3s0
+```
+
+## Logging
+
+Logging is handled by [Rust env_logger](https://docs.rs/env_logger/latest/env_logger/).
+
 ## References
 
 - <https://datatracker.ietf.org/doc/html/rfc8415#section-6.1>

src/main.rs

@@ -1,3 +1,7 @@
+use anyhow::{
+    Context,
+    Result,
+};
 use clap::Parser;
 use dhcproto::{
     Decodable,
@@ -13,6 +17,12 @@ use dhcproto::{
     },
 };
 use ipnetwork;
+use log::{
+    debug,
+    log_enabled,
+    info,
+    Level,
+};
 use pnet;
 use std::net::SocketAddrV6;
 use tokio::net::UdpSocket;
@@ -30,14 +40,16 @@ struct Cli {
 }
 
 #[tokio::main]
-async fn main() {
+async fn main() -> Result<()>{
+    env_logger::init();
+
     let cli = Cli::parse();
 
     let all_interfaces = pnet::datalink::interfaces();
     let selected_interface = all_interfaces
         .iter()
         .find(|i| i.name == cli.interface)
-        .expect(format!("No interface found with name: {}", cli.interface).as_str());
+        .with_context(|| format!("No interface found with name: {}", cli.interface))?;
 
     let ipv6_addresses = selected_interface.ips
         .iter()
@@ -50,10 +62,14 @@ async fn main() {
 
     // Just take the first address found on the interface
     let selected_address = ipv6_link_local_addresses.next()
-        .expect("No IPv6 link local address assigned to this interface");
+        .context("No IPv6 link local address assigned to this interface")?;
 
     let socket_addr = SocketAddrV6::new(selected_address.ip(), DHCP_CLIENT_PORT, 0, selected_interface.index.clone());
-    let sock = UdpSocket::bind(socket_addr).await.unwrap();
+    let sock = UdpSocket::bind(socket_addr).await
+        .context("Unable to bind UDP socket")?;
+
+    info!("Listening on {}", sock.local_addr()
+        .context("Failed to fetch address socket bound to")?);
 
     let remote_addr = SocketAddrV6::new(ALL_DHCP_RELAY_AGENTS_AND_SERVERS.parse().unwrap(), DHCP_RELAY_AGENT_AND_SERVER_PORT, 0, selected_interface.index.clone());
 
@@ -70,20 +86,28 @@ async fn main() {
 
     let mut msg_buf = Vec::new();
     let mut msg_encoder = Encoder::new(&mut msg_buf);
-    msg.encode(&mut msg_encoder).unwrap(); // Serializes msg to msg_buf
+    msg.encode(&mut msg_encoder)
+        .context("Unable to serialize DHCP options for message to send")?; // Serializes msg to msg_buf
 
-    sock.send_to(&msg_buf, remote_addr).await.unwrap();
+    sock.send_to(&msg_buf, remote_addr).await
+        .context("Failed to send DHCPv6 INFORMATION-REQUEST message")?;
 
     loop {
         let mut recv_buf = [0; 1024];
-        let (len, recv_addr) = sock.recv_from(&mut recv_buf).await.unwrap();
-        let recv_msg = Message::decode(&mut Decoder::new(&recv_buf)).unwrap();
+        let (len, recv_addr) = sock.recv_from(&mut recv_buf).await
+            .context("Failed to receive DHCPv6 response")?;
+        let recv_msg = Message::decode(&mut Decoder::new(&recv_buf))
+            .context("Unable to parse DHCPv6 response message")?;
 
         if recv_msg.xid() == msg.xid() {
-            println!("{:?} bytes received from {:?}", len, recv_addr);
-            println!("{}", &recv_buf[..len].escape_ascii().to_string());
+            info!("{:?} bytes received from {:?}", len, recv_addr);
+            if log_enabled!(Level::Debug) {
+                debug!("Received packet: {}", hex::encode(&recv_buf[..len]));
+            }
             println!("{}", &recv_msg);
             break;
         }
     }
+
+    Ok(())
 }