feat: separate zstd and faketcp into features (#1861)

* feat: separate faketcp into a feature
* fix: no need to initialize out_len
* feat: separate zstd into a feature
* clippy: remove unnecessary cast, because for unix size_t always equals usize

easytier/src/tunnel/fake_tcp/netfilter/macos_bpf.rs

@@ -716,7 +716,7 @@ fn open_bpf_device() -> io::Result<OwnedFd> {
 
 fn set_ifreq_name(ifr: &mut libc::ifreq, interface_name: &str) -> io::Result<()> {
     let bytes = interface_name.as_bytes();
-    let ifnamsiz = libc::IFNAMSIZ as usize;
+    let ifnamsiz = libc::IFNAMSIZ;
     if bytes.len() >= ifnamsiz {
         return Err(io::Error::new(
             io::ErrorKind::InvalidInput,
@@ -932,7 +932,7 @@ impl MacosBpfTun {
 
                     let pkt_start = off + pkt_range.start;
                     let pkt_end = off + pkt_range.end;
-                    let shift = (pkt_range.start as usize).saturating_sub(hdr_len as usize);
+                    let shift = pkt_range.start.saturating_sub(hdr_len as usize);
                     if shift != 0 && shifted_record_logs_left > 0 {
                         shifted_record_logs_left -= 1;
                         warn!(
@@ -1039,7 +1039,7 @@ impl stack::Tun for MacosBpfTun {
             Ok(())
         };
 
-        let mut out_len = 0usize;
+        let mut out_len: usize;
         let res = match self.link_type {
             LinkType::En10Mb => {
                 out_len = packet.len();

easytier/src/tunnel/mod.rs

@@ -15,7 +15,6 @@ use self::packet_def::ZCPacket;
 
 pub mod buf;
 pub mod common;
-pub mod fake_tcp;
 pub mod filter;
 pub mod mpsc;
 pub mod packet_def;
@@ -33,6 +32,9 @@ pub const PROTO_PORT_OFFSET: &[(&str, u16)] = &[
     ("faketcp", 3),
 ];
 
+#[cfg(feature = "faketcp")]
+pub mod fake_tcp;
+
 #[cfg(feature = "wireguard")]
 pub mod wireguard;
 

easytier/src/tunnel/packet_def.rs

@@ -288,6 +288,7 @@ pub const AES_GCM_ENCRYPTION_RESERVED: usize = std::mem::size_of::<AesGcmTail>()
 #[repr(u8)]
 pub enum CompressorAlgo {
     None = 0,
+    #[cfg(feature = "zstd")]
     ZstdDefault = 1,
 }
 
@@ -301,6 +302,7 @@ pub const COMPRESSOR_TAIL_SIZE: usize = std::mem::size_of::<CompressorTail>();
 impl CompressorTail {
     pub fn get_algo(&self) -> Option<CompressorAlgo> {
         match self.algo {
+            #[cfg(feature = "zstd")]
             1 => Some(CompressorAlgo::ZstdDefault),
             _ => None,
         }