actually bind to the interfaces

this server is now truly multi-interface

2 files changed, 20 insertions, 12 deletions

diff --git a/src/main.rs b/src/main.rs
index 18e88e2..082a5f2 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -62,24 +62,29 @@ fn run(link: String, subnet_id: u8) -> Result<()> {
 
     let sock = Socket::new(Domain::IPV4, Type::DGRAM, None)?;
 
-    let address = SocketAddr::from_str("0.0.0.0:67")?;
-    sock.bind(&address.into())?;
-
     sock.set_broadcast(true)?;
     sock.set_reuse_port(true)?;
+    sock.set_reuse_address(true)?;
 
     // Bind socket to interface.
     unsafe {
-        let link_index = libc::if_nametoindex(CString::new(link.clone())?.into_raw());
+        let link_index = CString::new(link.clone())?.into_raw();
 
         setsockopt(
             sock.as_raw_fd(),
-            libc::IPPROTO_IP,
+            libc::SOL_SOCKET,
             libc::SO_BINDTODEVICE,
             link_index,
+            link.len() as i32,
         )?;
+
+        // Prevent memory leak.
+        let _ = CString::from_raw(link_index);
     }
 
+    let address = SocketAddr::from_str("0.0.0.0:67")?;
+    sock.bind(&address.into())?;
+
     loop {
         let mut buf = [MaybeUninit::new(0); 1024];
         let (n, remote) = sock.recv_from(&mut buf)?;
diff --git a/src/util.rs b/src/util.rs
index 7fa8f5e..d131753 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -1,10 +1,8 @@
 use crate::error::{Error, Result};
 
-use std::ffi::c_int;
+use std::ffi::{c_char, c_int};
 use std::io;
-use std::mem;
 use std::net::Ipv4Addr;
-use std::ptr;
 
 /// Helper macro to execute a system call that returns an `io::Result`.
 macro_rules! syscall {
@@ -35,14 +33,19 @@ pub fn local_ip(link: &str) -> Result<Ipv4Addr> {
 }
 
 #[allow(clippy::missing_safety_doc)]
-pub unsafe fn setsockopt<T>(fd: c_int, opt: c_int, val: c_int, payload: T) -> io::Result<()> {
-    let payload = ptr::addr_of!(payload).cast();
+pub unsafe fn setsockopt(
+    fd: c_int,
+    opt: c_int,
+    val: c_int,
+    payload: *const c_char,
+    optlen: c_int,
+) -> io::Result<()> {
     syscall!(setsockopt(
         fd,
         opt,
         val,
-        payload,
-        mem::size_of::<T>() as libc::socklen_t
+        payload.cast(),
+        optlen as libc::socklen_t
     ))
     .map(|_| ())
 }