Add Nat expression

2 files changed, 51 insertions, 0 deletions

diff --git a/nftnl/src/expr/mod.rs b/nftnl/src/expr/mod.rs
index 19a9d3f..b4695fb 100644
--- a/nftnl/src/expr/mod.rs
+++ b/nftnl/src/expr/mod.rs
@@ -54,6 +54,9 @@ pub use self::masquerade::*;
 mod meta;
 pub use self::meta::*;
 
+mod nat;
+pub use self::nat::*;
+
 mod payload;
 pub use self::payload::*;
 
diff --git a/nftnl/src/expr/nat.rs b/nftnl/src/expr/nat.rs
new file mode 100644
index 0000000..82c6ecc
--- /dev/null
+++ b/nftnl/src/expr/nat.rs
@@ -0,0 +1,48 @@
+use super::{Expression, Register, Rule};
+use crate::ProtoFamily;
+use nftnl_sys::{self as sys, libc};
+use std::os::raw::c_char;
+
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
+#[repr(i32)]
+pub enum NatType {
+    /// Source NAT. Changes the source address of a packet
+    SNat = libc::NFT_NAT_SNAT,
+    /// Destination NAT. Changeth the destination address of a packet
+    DNat = libc::NFT_NAT_DNAT,
+}
+
+/// A source or destination NAT statement. Modifies the source or destination address
+/// (and possibly port) of packets.
+pub struct Nat {
+    pub nat_type: NatType,
+    pub family: ProtoFamily,
+    pub ip_reg: Register,
+    pub port_reg: Option<Register>,
+}
+
+impl Expression for Nat {
+    fn to_expr(&self, _rule: &Rule) -> *mut sys::nftnl_expr {
+        let expr =
+            try_alloc!(unsafe { sys::nftnl_expr_alloc(b"nat\0" as *const _ as *const c_char) });
+
+        unsafe {
+            sys::nftnl_expr_set_u32(expr, sys::NFTNL_EXPR_NAT_TYPE as u16, self.nat_type as u32);
+            sys::nftnl_expr_set_u32(expr, sys::NFTNL_EXPR_NAT_FAMILY as u16, self.family as u32);
+            sys::nftnl_expr_set_u32(
+                expr,
+                sys::NFTNL_EXPR_NAT_REG_ADDR_MIN as u16,
+                self.ip_reg.to_raw(),
+            );
+            if let Some(port_reg) = self.port_reg {
+                sys::nftnl_expr_set_u32(
+                    expr,
+                    sys::NFTNL_EXPR_NAT_REG_PROTO_MIN as u16,
+                    port_reg.to_raw(),
+                );
+            }
+        }
+
+        expr
+    }
+}