From 330126271be94ed8c3cd553fec86a5f9e2cbf188 Mon Sep 17 00:00:00 2001
From: Huang-Huang Bao <i@eh5.me>
Date: Fri, 5 Apr 2024 19:51:18 +0800
Subject: [PATCH] fix: guard against division by zero in libbpf-rs

---
 src/instance.rs | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/src/instance.rs b/src/instance.rs
index 466050e..8d02d6f 100644
--- a/src/instance.rs
+++ b/src/instance.rs
@@ -919,12 +919,14 @@ fn remove_binding_and_ct_entires(skel: &EinatSkel, external_addr: IpAddr) -> Res
         }
     }
 
-    map_binding.delete_batch(
-        &to_delete_binding_keys,
-        (to_delete_binding_keys.len() / core::mem::size_of::<MapBindingKey>()) as _,
-        MapFlags::ANY,
-        MapFlags::ANY,
-    )?;
+    if !to_delete_binding_keys.is_empty() {
+        map_binding.delete_batch(
+            &to_delete_binding_keys,
+            (to_delete_binding_keys.len() / core::mem::size_of::<MapBindingKey>()) as _,
+            MapFlags::ANY,
+            MapFlags::ANY,
+        )?;
+    }
 
     let mut to_delete_ct_keys = Vec::new();
     for ct_key_raw in map_ct.keys() {
@@ -934,12 +936,14 @@ fn remove_binding_and_ct_entires(skel: &EinatSkel, external_addr: IpAddr) -> Res
         }
     }
 
-    map_ct.delete_batch(
-        &to_delete_ct_keys,
-        (to_delete_ct_keys.len() / core::mem::size_of::<MapCtKey>()) as _,
-        MapFlags::ANY,
-        MapFlags::ANY,
-    )?;
+    if !to_delete_ct_keys.is_empty() {
+        map_ct.delete_batch(
+            &to_delete_ct_keys,
+            (to_delete_ct_keys.len() / core::mem::size_of::<MapCtKey>()) as _,
+            MapFlags::ANY,
+            MapFlags::ANY,
+        )?;
+    }
 
     Ok(())
 }