1 files changed, 32 insertions, 9 deletions

diff --git a/rustables/src/expr/lookup.rs b/rustables/src/expr/lookup.rs
index ac22440..7796b29 100644
--- a/rustables/src/expr/lookup.rs
+++ b/rustables/src/expr/lookup.rs
@@ -1,29 +1,52 @@
-use super::{Expression, Rule};
+use super::{DeserializationError, Expression, Rule};
 use crate::set::Set;
 use rustables_sys::{self as sys, libc};
-use std::ffi::CString;
+use std::ffi::{CStr, CString};
 use std::os::raw::c_char;
 
+#[derive(Debug, PartialEq)]
 pub struct Lookup {
     set_name: CString,
     set_id: u32,
 }
 
 impl Lookup {
-    pub fn new<K>(set: &Set<'_, K>) -> Self {
-        Lookup {
-            set_name: set.get_name().to_owned(),
+    /// Creates a new lookup entry.
+    /// May return None if the set have no name.
+    pub fn new<K>(set: &Set<'_, K>) -> Option<Self> {
+        set.get_name().map(|set_name| Lookup {
+            set_name: set_name.to_owned(),
             set_id: set.get_id(),
-        }
+        })
     }
 }
 
 impl Expression for Lookup {
+    fn get_raw_name() -> *const libc::c_char {
+        b"lookup\0" as *const _ as *const c_char
+    }
+
+    fn from_expr(expr: *const sys::nftnl_expr) -> Result<Self, DeserializationError>
+    where
+        Self: Sized,
+    {
+        unsafe {
+            let set_name = sys::nftnl_expr_get_str(expr, sys::NFTNL_EXPR_LOOKUP_SET as u16);
+            let set_id = sys::nftnl_expr_get_u32(expr, sys::NFTNL_EXPR_LOOKUP_SET_ID as u16);
+
+            if set_name.is_null() {
+                return Err(DeserializationError::NullPointer);
+            }
+
+            let set_name = CStr::from_ptr(set_name).to_owned();
+
+            Ok(Lookup { set_id, set_name })
+        }
+    }
+
     fn to_expr(&self, _rule: &Rule) -> *mut sys::nftnl_expr {
         unsafe {
-            let expr = try_alloc!(sys::nftnl_expr_alloc(
-                b"lookup\0" as *const _ as *const c_char
-            ));
+            let expr = try_alloc!(sys::nftnl_expr_alloc(Self::get_raw_name()));
 
             sys::nftnl_expr_set_u32(
                 expr,