Fix netfilter test's setsockopt to actually succeed

src/test/netfilter.c

@@ -61,19 +61,6 @@ int main(void) {
   test_assert(ret == 0);
   test_assert(getentries_size == sizeof(struct ipt_get_entries) + info.size);
 
-  // matches will be empty
-  struct xt_entry_target target;
-  const char* target_name = "MASQUERADE";
-  target.u.user.target_size = strlen(target_name) - 1;
-  memcpy(target.u.user.name, target_name, strlen(target_name) - 1);
-
-  struct ipt_entry entry;
-  memset(&entry, 0, sizeof(struct ipt_entry));
-  entry.ip.src.s_addr = 0x10;
-  entry.ip.smsk.s_addr = 0xffffff;
-  entry.target_offset = 0x70;
-  entry.next_offset = 0x98;
-
   // Allocate space to receive counters
   struct xt_counters* counters =
       malloc(sizeof(struct xt_counters) * info.num_entries);
@@ -82,8 +69,9 @@ int main(void) {
 
   struct ipt_replace repl;
   strcpy(repl.name, "nat");
-  repl.num_entries = info.num_entries + 1;
-  repl.size = info.size + entry.next_offset;
+  repl.valid_hooks = info.valid_hooks;
+  repl.num_entries = info.num_entries;
+  repl.size = info.size;
   memcpy(repl.hook_entry, info.hook_entry, sizeof(repl.hook_entry));
   memcpy(repl.underflow, info.underflow, sizeof(repl.underflow));
   repl.num_counters = info.num_entries;
@@ -95,28 +83,18 @@ int main(void) {
   // Assemble structure
   memcpy(final, &repl, sizeof(struct ipt_replace));
 
-  // Copy over original entries and insert our new one as the second-to-last one
   char* src_ptr = (char*)entries->entrytable;
   char* dest_ptr = (char*)((struct ipt_replace*)final)->entries;
   for (size_t i = 0; i < info.num_entries; ++i) {
-    if (i == info.num_entries - 2) {
-      memcpy(dest_ptr, &entry, sizeof(struct ipt_entry));
-      dest_ptr += sizeof(struct ipt_entry);
-      memcpy(dest_ptr, &target, sizeof(struct xt_entry_target));
-      dest_ptr += sizeof(struct xt_entry_target);
-      size_t npad = entry.next_offset - sizeof(struct xt_entry_target);
-      memset(dest_ptr, 0, npad);
-      dest_ptr += npad;
-    }
     struct ipt_entry* cur_entry = (struct ipt_entry*)src_ptr;
     memcpy(dest_ptr, src_ptr, cur_entry->next_offset);
     dest_ptr += cur_entry->next_offset;
     src_ptr += cur_entry->next_offset;
   }
 
   // Finally pass this off to the kernel
-  test_assert(
-      setsockopt(sock_fd, SOL_IP, IPT_SO_SET_REPLACE, final, final_size));
+  ret = setsockopt(sock_fd, SOL_IP, IPT_SO_SET_REPLACE, final, final_size);
+  test_assert(ret == 0);
 
   // Verify that the counters array was overwritten. Since we don't know the
   // exact value here, just make sure some bytes were written. After every byte