bpf: sk_skb: add ::cb() and ::cb_mut() to work with skb->cb

bpf/aya-bpf/src/programs/sk_skb.rs

@@ -30,6 +30,16 @@ impl SkSkbContext {
         unsafe { *self.skb }.mark = mark;
     }
 
+    #[inline]
+    pub fn cb(&self) -> &[u32] {
+        unsafe { &(*self.skb).cb }
+    }
+
+    #[inline]
+    pub fn cb_mut(&self) -> &mut [u32] {
+        unsafe { &mut (*self.skb).cb }
+    }
+
     #[inline]
     pub fn load<T>(&self, offset: usize) -> Result<T, c_long> {
         unsafe {