1 files changed, 112 insertions, 0 deletions
diff --git a/src/plugins/bpf_trace_filter/bpf_trace_filter.c b/src/plugins/bpf_trace_filter/bpf_trace_filter.c
new file mode 100644
index 00000000000..9d86c8483a6
--- /dev/null
+++ b/src/plugins/bpf_trace_filter/bpf_trace_filter.c
@@ -0,0 +1,112 @@
+/*
+ *------------------------------------------------------------------
+ * Copyright (c) 2023 Cisco and/or its affiliates.
+ * 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 <vlib/vlib.h>
+#include <bpf_trace_filter/bpf_trace_filter.h>
+
+clib_error_t *
+bpf_trace_filter_init (vlib_main_t *vm)
+{
+  bpf_trace_filter_main_t *btm = &bpf_trace_filter_main;
+  btm->pcap = pcap_open_dead (DLT_EN10MB, 65535);
+
+  return 0;
+}
+
+int vnet_is_packet_traced (vlib_buffer_t *b, u32 classify_table_index,
+			   int func);
+
+u8 *
+format_bpf_trace_filter (u8 *s, va_list *a)
+{
+  bpf_trace_filter_main_t *btm = va_arg (*a, bpf_trace_filter_main_t *);
+  struct bpf_insn *insn;
+
+  if (!btm->prog_set)
+    return format (s, "bpf trace filter is not set");
+
+  insn = btm->prog.bf_insns;
+  for (int i = 0; i < btm->prog.bf_len; insn++, i++)
+    s = format (s, "%s\n", bpf_image (insn, i));
+
+  return s;
+}
+
+clib_error_t *
+bpf_trace_filter_set_unset (const char *bpf_expr, u8 is_del, u8 optimize)
+{
+  bpf_trace_filter_main_t *btm = &bpf_trace_filter_main;
+  if (is_del)
+    {
+      if (btm->prog_set)
+	{
+	  btm->prog_set = 0;
+	  pcap_freecode (&btm->prog);
+	}
+    }
+  else if (bpf_expr)
+    {
+      if (btm->prog_set)
+	pcap_freecode (&btm->prog);
+      btm->prog_set = 0;
+      if (pcap_compile (btm->pcap, &btm->prog, (char *) bpf_expr, optimize,
+			PCAP_NETMASK_UNKNOWN))
+	{
+	  return clib_error_return (0, "Failed pcap_compile of %s", bpf_expr);
+	}
+      btm->prog_set = 1;
+    }
+  return 0;
+};
+
+int
+bpf_is_packet_traced (vlib_buffer_t *b, u32 classify_table_index, int func)
+{
+  bpf_trace_filter_main_t *bfm = &bpf_trace_filter_main;
+  struct pcap_pkthdr phdr = { 0 };
+  int res;
+  int res1;
+
+  if (classify_table_index != ~0 &&
+      (res1 = vnet_is_packet_traced (b, classify_table_index, 0)) != 1)
+    return res1;
+
+  if (!bfm->prog_set)
+    return 1;
+
+  phdr.caplen = b->current_length;
+  phdr.len = b->current_length;
+  res = pcap_offline_filter (&bfm->prog, &phdr, vlib_buffer_get_current (b));
+  return res != 0;
+}
+
+VLIB_REGISTER_TRACE_FILTER_FUNCTION (bpf_trace_filter_fn, static) = {
+  .name = "bpf_trace_filter",
+  .description = "bpf based trace filter",
+  .priority = 10,
+  .function = bpf_is_packet_traced
+};
+
+VLIB_INIT_FUNCTION (bpf_trace_filter_init);
+bpf_trace_filter_main_t bpf_trace_filter_main;
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */