Merge pull request #1593 from netgroup-polito/bpf_prog_table_delete_element

Allow to delete elements from prog tables

src/cc/api/BPFTable.h

@@ -287,6 +287,12 @@ public:
       return StatusTuple(-1, "Error updating value: %s", std::strerror(errno));
     return StatusTuple(0);
   }
+
+  StatusTuple remove_value(const int& index) {
+    if (!this->remove(const_cast<int*>(&index)))
+      return StatusTuple(-1, "Error removing value: %s", std::strerror(errno));
+    return StatusTuple(0);
+  }
 };
 
 }  // namespace ebpf

tests/cc/CMakeLists.txt

@@ -17,6 +17,7 @@ add_executable(test_libbcc
 	test_bpf_table.cc
 	test_hash_table.cc
 	test_perf_event.cc
+	test_prog_table.cc
 	test_usdt_args.cc
 	test_usdt_probes.cc
 	utils.cc)

tests/cc/test_prog_table.cc

+/*
+ * Copyright (c) 2018 Politecnico di Torino
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "BPF.h"
+
+#include "catch.hpp"
+
+TEST_CASE("test prog table", "[prog_table]") {
+  const std::string BPF_PROGRAM = R"(
+    BPF_TABLE("prog", int, int, myprog, 16);
+  )";
+
+  const std::string BPF_PROGRAM2 = R"(
+    int hello(struct __sk_buff *skb) {
+      return 1;
+    }
+  )";
+
+  ebpf::StatusTuple res(0);
+
+  ebpf::BPF bpf;
+  res = bpf.init(BPF_PROGRAM);
+  REQUIRE(res.code() == 0);
+
+  ebpf::BPFProgTable t = bpf.get_prog_table("myprog");
+
+  ebpf::BPF bpf2;
+  res = bpf2.init(BPF_PROGRAM2);
+  REQUIRE(res.code() == 0);
+
+  int fd;
+  res = bpf2.load_func("hello", BPF_PROG_TYPE_SCHED_CLS, fd);
+  REQUIRE(res.code() == 0);
+
+  SECTION("update and remove") {
+    // update element
+    res = t.update_value(0, fd);
+    REQUIRE(res.code() == 0);
+
+    // remove element
+    res = t.remove_value(0);
+    REQUIRE(res.code() == 0);
+
+    // update out of range element
+    res = t.update_value(17, fd);
+    REQUIRE(res.code() != 0);
+
+    // remove out of range element
+    res = t.remove_value(17);
+    REQUIRE(res.code() != 0);
+  }
+}