add support for tproxy(udp)

src/lib.rs

@@ -76,6 +76,7 @@ pub struct RecvMeta {
  pub dst_local_ip: Option<IpAddr>,
  /// interface index that datagram was received on
  pub ifindex: u32,
+ pub orig_dst: Option<SocketAddr>,
 }
 
 impl Default for RecvMeta {
@@ -89,6 +90,7 @@ impl Default for RecvMeta {
  dst_ip: None,
  dst_local_ip: None,
  ifindex: 0,
+ orig_dst: None,
  }
  }
 }

src/unix.rs

@@ -1074,6 +1074,7 @@ fn decode_recv(
  let mut ifindex = 0;
  #[allow(unused_mut)] // only mutable on Linux
  let mut stride = len;
+ let mut orig_dst = None;
 
  let cmsg_iter = unsafe { cmsg::Iter::new(hdr) };
  for cmsg in cmsg_iter {
@@ -1118,6 +1119,13 @@ fn decode_recv(
  (libc::SOL_UDP, libc::UDP_GRO) => unsafe {
  stride = cmsg::decode::<libc::c_int>(cmsg) as usize;
  },
+ #[cfg(target_os = "linux")]
+ (libc::SOL_IP, libc::IP_ORIGDSTADDR) => unsafe {
+ let addr_in = cmsg::decode::<libc::sockaddr_in>(cmsg);
+ let addr = Ipv4Addr::from(addr_in.sin_addr.s_addr.to_ne_bytes());
+ let port = u16::from_be(addr_in.sin_port);
+ orig_dst = Some(SocketAddr::V4(SocketAddrV4::new(addr, port)));
+ },
  _ => {}
  }
  }
@@ -1153,6 +1161,7 @@ fn decode_recv(
  dst_ip,
  dst_local_ip,
  ifindex,
+ orig_dst,
  }
 }