diff --git a/src/ws/frame.rs b/src/ws/frame.rs
index 871cc7619..f71564e82 100644
--- a/src/ws/frame.rs
+++ b/src/ws/frame.rs
@@ -94,9 +94,12 @@ impl Frame {
                 Async::Ready(None) => return Ok(Async::Ready(None)),
                 Async::NotReady => return Ok(Async::NotReady),
             };
-            let len = NetworkEndian::read_uint(&buf[idx..], 8) as usize;
+            let len = NetworkEndian::read_uint(&buf[idx..], 8);
+            if len > max_size as u64 {
+                return Err(ProtocolError::Overflow);
+            }
             idx += 8;
-            len
+            len as usize
         } else {
             len as usize
         };
@@ -165,9 +168,12 @@ impl Frame {
             if chunk_len < 10 {
                 return Ok(Async::NotReady);
             }
-            let len = NetworkEndian::read_uint(&chunk[idx..], 8) as usize;
+            let len = NetworkEndian::read_uint(&chunk[idx..], 8);
+            if len > max_size as u64 {
+                return Err(ProtocolError::Overflow);
+            }
             idx += 8;
-            len
+            len as usize
         } else {
             len as usize
         };
@@ -255,6 +261,8 @@ impl Frame {
 
         // unmask
         if let Some(mask) = mask {
+            // Unsafe: request body stream is owned by WsStream. only one ref to
+            // bytes exists. Bytes object get freezed in continuous non-overlapping blocks
             let p: &mut [u8] = unsafe {
                 let ptr: &[u8] = &data;
                 &mut *(ptr as *const _ as *mut _)
@@ -272,7 +280,7 @@ impl Frame {
     /// Parse the payload of a close frame.
     pub fn parse_close_payload(payload: &Binary) -> Option<CloseReason> {
         if payload.len() >= 2 {
-            let raw_code = NetworkEndian::read_uint(payload.as_ref(), 2) as u16;
+            let raw_code = NetworkEndian::read_u16(payload.as_ref());
             let code = CloseCode::from(raw_code);
             let description = if payload.len() > 2 {
                 Some(String::from_utf8_lossy(&payload.as_ref()[2..]).into())
diff --git a/src/ws/mask.rs b/src/ws/mask.rs
index d5d5ee92d..16f0f6b15 100644
--- a/src/ws/mask.rs
+++ b/src/ws/mask.rs
@@ -4,75 +4,71 @@ use std::cmp::min;
 use std::mem::uninitialized;
 use std::ptr::copy_nonoverlapping;
 
-/// Mask/unmask a frame.
-#[inline]
-pub fn apply_mask(buf: &mut [u8], mask: u32) {
-    unsafe { apply_mask_fast32(buf, mask) }
-}
-
 /// Faster version of `apply_mask()` which operates on 8-byte blocks.
 ///
 /// unsafe because uses pointer math and bit operations for performance
 #[inline]
 #[cfg_attr(feature = "cargo-clippy", allow(cast_lossless))]
-unsafe fn apply_mask_fast32(buf: &mut [u8], mask_u32: u32) {
-    let mut ptr = buf.as_mut_ptr();
-    let mut len = buf.len();
+pub(crate) fn apply_mask(buf: &mut [u8], mask_u32: u32) {
+    unsafe {
+        let mut ptr = buf.as_mut_ptr();
+        let mut len = buf.len();
 
-    // Possible first unaligned block.
-    let head = min(len, (8 - (ptr as usize & 0x7)) & 0x3);
-    let mask_u32 = if head > 0 {
-        let n = if head > 4 { head - 4 } else { head };
+        // Possible first unaligned block.
+        let head = min(len, (8 - (ptr as usize & 0x7)) & 0x3);
+        let mask_u32 = if head > 0 {
+            let n = if head > 4 { head - 4 } else { head };
 
-        let mask_u32 = if n > 0 {
-            xor_mem(ptr, mask_u32, n);
-            ptr = ptr.offset(head as isize);
-            len -= n;
-            if cfg!(target_endian = "big") {
-                mask_u32.rotate_left(8 * n as u32)
+            let mask_u32 = if n > 0 {
+                xor_mem(ptr, mask_u32, n);
+                ptr = ptr.offset(head as isize);
+                len -= n;
+                if cfg!(target_endian = "big") {
+                    mask_u32.rotate_left(8 * n as u32)
+                } else {
+                    mask_u32.rotate_right(8 * n as u32)
+                }
             } else {
-                mask_u32.rotate_right(8 * n as u32)
+                mask_u32
+            };
+
+            if head > 4 {
+                *(ptr as *mut u32) ^= mask_u32;
+                ptr = ptr.offset(4);
+                len -= 4;
             }
+            mask_u32
         } else {
             mask_u32
         };
 
-        if head > 4 {
+        if len > 0 {
+            debug_assert_eq!(ptr as usize % 4, 0);
+        }
+
+        // Properly aligned middle of the data.
+        if len >= 8 {
+            let mut mask_u64 = mask_u32 as u64;
+            mask_u64 = mask_u64 << 32 | mask_u32 as u64;
+
+            while len >= 8 {
+                *(ptr as *mut u64) ^= mask_u64;
+                ptr = ptr.offset(8);
+                len -= 8;
+            }
+        }
+
+        while len >= 4 {
             *(ptr as *mut u32) ^= mask_u32;
             ptr = ptr.offset(4);
             len -= 4;
         }
-        mask_u32
-    } else {
-        mask_u32
-    };
 
-    if len > 0 {
-        debug_assert_eq!(ptr as usize % 4, 0);
-    }
-
-    // Properly aligned middle of the data.
-    if len >= 8 {
-        let mut mask_u64 = mask_u32 as u64;
-        mask_u64 = mask_u64 << 32 | mask_u32 as u64;
-
-        while len >= 8 {
-            *(ptr as *mut u64) ^= mask_u64;
-            ptr = ptr.offset(8);
-            len -= 8;
+        // Possible last block.
+        if len > 0 {
+            xor_mem(ptr, mask_u32, len);
         }
     }
-
-    while len >= 4 {
-        *(ptr as *mut u32) ^= mask_u32;
-        ptr = ptr.offset(4);
-        len -= 4;
-    }
-
-    // Possible last block.
-    if len > 0 {
-        xor_mem(ptr, mask_u32, len);
-    }
 }
 
 #[inline]