Specify interface as cmd arg

Cargo.lock

@@ -17,6 +17,15 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f26201604c87b1e01bd3d98f8d5d9a8fcbb815e8cedb41ffccbeb4bf593a35fe"
 
+[[package]]
+name = "aho-corasick"
+version = "1.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e60d3430d3a69478ad0993f19238d2df97c507009a52b3c10addcd7f6bcb916"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "async-trait"
 version = "0.1.81"
@@ -103,6 +112,8 @@ version = "0.1.0"
 dependencies = [
  "dhcproto",
  "hex",
+ "ipnetwork",
+ "pnet",
  "tokio",
 ]
 
@@ -184,6 +195,12 @@ version = "0.29.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "40ecd4077b5ae9fd2e9e169b102c6c330d0605168eb0e8bf79952b256dbefffd"
 
+[[package]]
+name = "glob"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d2fabcfbdc87f4758337ca535fb41a6d701b65693ce38287d856d1674551ec9b"
+
 [[package]]
 name = "heck"
 version = "0.4.1"
@@ -229,6 +246,15 @@ version = "2.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8f518f335dce6725a761382244631d86cf0ccb2863413590b31338feb467f9c3"
 
+[[package]]
+name = "ipnetwork"
+version = "0.20.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bf466541e9d546596ee94f9f69590f89473455f88372423e0008fc1a7daf100e"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "lazy_static"
 version = "1.5.0"
@@ -274,6 +300,12 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "no-std-net"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "43794a0ace135be66a25d3ae77d41b91615fb68ae937f904090203e81f755b65"
+
 [[package]]
 name = "object"
 version = "0.36.3"
@@ -307,6 +339,97 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8b870d8c151b6f2fb93e84a13146138f05d02ed11c7e7c54f8826aaaf7c9f184"
 
+[[package]]
+name = "pnet"
+version = "0.35.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "682396b533413cc2e009fbb48aadf93619a149d3e57defba19ff50ce0201bd0d"
+dependencies = [
+ "ipnetwork",
+ "pnet_base",
+ "pnet_datalink",
+ "pnet_packet",
+ "pnet_sys",
+ "pnet_transport",
+]
+
+[[package]]
+name = "pnet_base"
+version = "0.35.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ffc190d4067df16af3aba49b3b74c469e611cad6314676eaf1157f31aa0fb2f7"
+dependencies = [
+ "no-std-net",
+]
+
+[[package]]
+name = "pnet_datalink"
+version = "0.35.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e79e70ec0be163102a332e1d2d5586d362ad76b01cec86f830241f2b6452a7b7"
+dependencies = [
+ "ipnetwork",
+ "libc",
+ "pnet_base",
+ "pnet_sys",
+ "winapi",
+]
+
+[[package]]
+name = "pnet_macros"
+version = "0.35.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "13325ac86ee1a80a480b0bc8e3d30c25d133616112bb16e86f712dcf8a71c863"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "regex",
+ "syn 2.0.72",
+]
+
+[[package]]
+name = "pnet_macros_support"
+version = "0.35.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eed67a952585d509dd0003049b1fc56b982ac665c8299b124b90ea2bdb3134ab"
+dependencies = [
+ "pnet_base",
+]
+
+[[package]]
+name = "pnet_packet"
+version = "0.35.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4c96ebadfab635fcc23036ba30a7d33a80c39e8461b8bd7dc7bb186acb96560f"
+dependencies = [
+ "glob",
+ "pnet_base",
+ "pnet_macros",
+ "pnet_macros_support",
+]
+
+[[package]]
+name = "pnet_sys"
+version = "0.35.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7d4643d3d4db6b08741050c2f3afa9a892c4244c085a72fcda93c9c2c9a00f4b"
+dependencies = [
+ "libc",
+ "winapi",
+]
+
+[[package]]
+name = "pnet_transport"
+version = "0.35.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5f604d98bc2a6591cf719b58d3203fd882bdd6bf1db696c4ac97978e9f4776bf"
+dependencies = [
+ "libc",
+ "pnet_base",
+ "pnet_packet",
+ "pnet_sys",
+]
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.20"
@@ -364,12 +487,61 @@ dependencies = [
  "getrandom",
 ]
 
+[[package]]
+name = "regex"
+version = "1.10.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4219d74c6b67a3654a9fbebc4b419e22126d13d2f3c4a07ee0cb61ff79a79619"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "38caf58cc5ef2fed281f89292ef23f6365465ed9a41b7a7754eb4e26496c92df"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a66a03ae7c801facd77a29370b4faec201768915ac14a721ba36f20bc9c209b"
+
 [[package]]
 name = "rustc-demangle"
 version = "0.1.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "719b953e2095829ee67db738b3bfa9fa368c94900df327b3f07fe6e794d2fe1f"
 
+[[package]]
+name = "serde"
+version = "1.0.209"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "99fce0ffe7310761ca6bf9faf5115afbc19688edd00171d81b1bb1b116c63e09"
+dependencies = [
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.209"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a5831b979fd7b5439637af1752d535ff49f4860c0f341d1baeb6faf0f4242170"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.72",
+]
+
 [[package]]
 name = "shlex"
 version = "1.3.0"
@@ -577,6 +749,28 @@ version = "0.11.0+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9c8d87e72b64a3b4db28d11ce29237c246188f4f51057d65a7eab63b7987e423"
 
+[[package]]
+name = "winapi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+
 [[package]]
 name = "windows-sys"
 version = "0.52.0"

Cargo.toml

@@ -6,4 +6,6 @@ edition = "2021"
 [dependencies]
 dhcproto = "0.12.0"
 hex = "0.4.3"
+ipnetwork = "0.20.0"
+pnet = "0.35.0"
 tokio = { version = "1.39.3", features = ["macros", "net", "rt-multi-thread"] }

src/main.rs

@@ -11,7 +11,12 @@ use dhcproto::{
         ORO,
     },
 };
-use std::net::SocketAddrV6;
+use ipnetwork;
+use pnet;
+use std::{
+    env,
+    net::SocketAddrV6,
+};
 use tokio::net::UdpSocket;
 
 const scope_id: u32 = 15;
@@ -23,7 +28,31 @@ const DHCP_Relay_Agent_and_Server_port: u16 = 547;
 
 #[tokio::main]
 async fn main() {
-    let socket_addr = SocketAddrV6::new("fe80::e3cf:4290:9165:505d".parse().unwrap(), DHCP_Client_port, 0, scope_id);
+    let mut args = env::args();
+    args.next(); // Skip executable name
+    // First argument is interface name
+    let interface_name = args.next().expect("No interface name specified");
+
+    let all_interfaces = pnet::datalink::interfaces();
+    let selected_interface = all_interfaces
+        .iter()
+        .find(|i| i.name == interface_name)
+        .expect(format!("No interface found with name: {}", interface_name).as_str());
+
+    let ipv6_addresses = selected_interface.ips
+        .iter()
+        .filter_map(|a| match a {
+            ipnetwork::IpNetwork::V6(a) => Some(a),
+            _ => None,
+        });
+    let mut ipv6_link_local_addresses = ipv6_addresses
+        .filter(|a| a.is_subnet_of("fe80::/10".parse().unwrap()));
+
+    // 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");
+
+    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 remote_addr = SocketAddrV6::new(All_DHCP_Relay_Agents_and_Servers.parse().unwrap(), DHCP_Relay_Agent_and_Server_port, 0, scope_id);