fix get_table_offline for percpu hash table

Use get_value() instead of lookup() as the value as in the case of
percpu tables the ValueType is an std::vector that has to be resized
before performing the lookup function.

Add also some testing for it.

Solves iovisor#1860

Signed-off-by: Mauricio Vasquez B <[email protected]>

src/cc/api/BPFTable.h

@@ -232,11 +232,14 @@ class BPFHashTable : public BPFTableBase<KeyType, ValueType> {
  KeyType cur;
  ValueType value;
 
+ StatusTuple r(0);
+
  if (!this->first(&cur))
  return res;
 
  while (true) {
- if (!this->lookup(&cur, &value))
+ r = get_value(cur, value);
+ if (r.code() != 0)
  break;
  res.emplace_back(cur, value);
  if (!this->next(&cur, &cur))

tests/cc/test_hash_table.cc

@@ -84,6 +84,10 @@ TEST_CASE("test hash table", "[hash_table]") {
  REQUIRE(pair.first % 3 == 0);
  REQUIRE(pair.first / 3 == pair.second);
  }
+
+ // clear table
+ t.clear_table_non_atomic();
+ REQUIRE(t.get_table_offline().size() == 0);
  }
 }
 
@@ -156,5 +160,34 @@ TEST_CASE("percpu hash table", "[percpu_hash_table]") {
  res = t.get_value(k, v2);
  REQUIRE(res.code() != 0);
  }
+
+ SECTION("walk table") {
+ std::vector<uint64_t> v(ncpus);
+
+ for (int k = 3; k <= 30; k+=3) {
+ for (size_t cpu = 0; cpu < ncpus; cpu++) {
+ v[cpu] = k * cpu;
+ }
+ res = t.update_value(k, v);
+ REQUIRE(res.code() == 0);
+ }
+
+ // get whole table
+ auto offline = t.get_table_offline();
+ REQUIRE(offline.size() == 10);
+ for (int i = 0; i < 10; i++) {
+ // check the key
+ REQUIRE(offline.at(i).first % 3 == 0);
+
+ // check value
+ for (size_t cpu = 0; cpu < ncpus; cpu++) {
+ REQUIRE(offline.at(i).second.at(cpu) == cpu * offline.at(i).first);
+ }
+ }
+
+ // clear table
+ t.clear_table_non_atomic();
+ REQUIRE(t.get_table_offline().size() == 0);
+ }
 }
 #endif