1 files changed, 48 insertions, 0 deletions
diff --git a/src/net/if_.rs b/src/net/if_.rs
new file mode 100644
index 00000000..26028f93
--- /dev/null
+++ b/src/net/if_.rs
@@ -0,0 +1,48 @@
+//! Network interface name resolution.
+//!
+//! Uses Linux and/or POSIX functions to resolve interface names like "eth0"
+//! or "socan1" into device numbers.
+
+use libc::{c_char, c_uint};
+use std::ffi::{CString, NulError};
+use std::io;
+
+/// Error that can occur during interface name resolution.
+#[derive(Debug)]
+pub enum NameToIndexError {
+    /// Failed to allocate a C-style string to for the syscall
+    NulError,
+    IOError(io::Error),
+}
+
+impl From<NulError> for NameToIndexError {
+    fn from(_: NulError) -> NameToIndexError {
+        NameToIndexError::NulError
+    }
+}
+
+impl From<io::Error> for NameToIndexError {
+    fn from(e: io::Error) -> NameToIndexError {
+        NameToIndexError::IOError(e)
+    }
+}
+
+extern {
+    fn if_nametoindex(ifname: *const c_char) -> c_uint;
+}
+
+/// Resolve an interface into a interface number.
+pub fn name_to_index(name: &str) -> Result<c_uint, NameToIndexError> {
+    let name = try!(CString::new(name));
+
+    let if_index;
+    unsafe {
+        if_index = if_nametoindex(name.as_ptr());
+    }
+
+    if if_index == 0 {
+        return Err(NameToIndexError::from(io::Error::last_os_error()));
+    }
+
+    Ok(if_index)
+}