1 files changed, 87 insertions, 0 deletions
diff --git a/src/expr/ct.rs b/src/expr/ct.rs
new file mode 100644
index 0000000..7d6614c
--- /dev/null
+++ b/src/expr/ct.rs
@@ -0,0 +1,87 @@
+use super::{DeserializationError, Expression, Rule};
+use crate::sys::{self, libc};
+use std::os::raw::c_char;
+
+bitflags::bitflags! {
+    pub struct States: u32 {
+        const INVALID = 1;
+        const ESTABLISHED = 2;
+        const RELATED = 4;
+        const NEW = 8;
+        const UNTRACKED = 64;
+    }
+}
+
+pub enum Conntrack {
+    State,
+    Mark { set: bool },
+}
+
+impl Conntrack {
+    fn raw_key(&self) -> u32 {
+        match *self {
+            Conntrack::State => libc::NFT_CT_STATE as u32,
+            Conntrack::Mark { .. } => libc::NFT_CT_MARK as u32,
+        }
+    }
+}
+
+impl Expression for Conntrack {
+    fn get_raw_name() -> *const c_char {
+        b"ct\0" as *const _ as *const c_char
+    }
+
+    fn from_expr(expr: *const sys::nftnl_expr) -> Result<Self, DeserializationError>
+    where
+        Self: Sized,
+    {
+        unsafe {
+            let ct_key = sys::nftnl_expr_get_u32(expr, sys::NFTNL_EXPR_CT_KEY as u16);
+            let ct_sreg_is_set = sys::nftnl_expr_is_set(expr, sys::NFTNL_EXPR_CT_SREG as u16);
+
+            match ct_key as i32 {
+                libc::NFT_CT_STATE => Ok(Conntrack::State),
+                libc::NFT_CT_MARK => Ok(Conntrack::Mark {
+                    set: ct_sreg_is_set,
+                }),
+                _ => Err(DeserializationError::InvalidValue),
+            }
+        }
+    }
+
+    fn to_expr(&self, _rule: &Rule) -> *mut sys::nftnl_expr {
+        unsafe {
+            let expr = try_alloc!(sys::nftnl_expr_alloc(Self::get_raw_name()));
+
+            if let Conntrack::Mark { set: true } = self {
+                sys::nftnl_expr_set_u32(
+                    expr,
+                    sys::NFTNL_EXPR_CT_SREG as u16,
+                    libc::NFT_REG_1 as u32,
+                );
+            } else {
+                sys::nftnl_expr_set_u32(
+                    expr,
+                    sys::NFTNL_EXPR_CT_DREG as u16,
+                    libc::NFT_REG_1 as u32,
+                );
+            }
+            sys::nftnl_expr_set_u32(expr, sys::NFTNL_EXPR_CT_KEY as u16, self.raw_key());
+
+            expr
+        }
+    }
+}
+
+#[macro_export]
+macro_rules! nft_expr_ct {
+    (state) => {
+        $crate::expr::Conntrack::State
+    };
+    (mark set) => {
+        $crate::expr::Conntrack::Mark { set: true }
+    };
+    (mark) => {
+        $crate::expr::Conntrack::Mark { set: false }
+    };
+}