1 files changed, 79 insertions, 0 deletions
diff --git a/src/expr/lookup.rs b/src/expr/lookup.rs
new file mode 100644
index 0000000..8e288a0
--- /dev/null
+++ b/src/expr/lookup.rs
@@ -0,0 +1,79 @@
+use super::{DeserializationError, Expression, Rule};
+use crate::set::Set;
+use crate::sys::{self, libc};
+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 {
+    /// 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(Self::get_raw_name()));
+
+            sys::nftnl_expr_set_u32(
+                expr,
+                sys::NFTNL_EXPR_LOOKUP_SREG as u16,
+                libc::NFT_REG_1 as u32,
+            );
+            sys::nftnl_expr_set_str(
+                expr,
+                sys::NFTNL_EXPR_LOOKUP_SET as u16,
+                self.set_name.as_ptr() as *const _ as *const c_char,
+            );
+            sys::nftnl_expr_set_u32(expr, sys::NFTNL_EXPR_LOOKUP_SET_ID as u16, self.set_id);
+
+            // This code is left here since it's quite likely we need it again when we get further
+            // if self.reverse {
+            //     sys::nftnl_expr_set_u32(expr, sys::NFTNL_EXPR_LOOKUP_FLAGS as u16,
+            //         libc::NFT_LOOKUP_F_INV as u32);
+            // }
+
+            expr
+        }
+    }
+}
+
+#[macro_export]
+macro_rules! nft_expr_lookup {
+    ($set:expr) => {
+        $crate::expr::Lookup::new($set)
+    };
+}