pcap-based dispatch tracer

To facilitate dispatch trajectory tracing, vlib_buffer_t decoding, etc.
through Wireshark

Change-Id: I31356b9fa1f40cba8830aaf10a86a9fbb7546438
Signed-off-by: Dave Barach <dave@barachs.net>

1 files changed, 269 insertions, 0 deletions

diff --git a/src/vppinfra/pcap.c b/src/vppinfra/pcap.c
new file mode 100644
index 00000000000..8f644e30f1d
--- /dev/null
+++ b/src/vppinfra/pcap.c
@@ -0,0 +1,269 @@
+/*
+ * Copyright (c) 2015 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.
+ */
+/*
+ * pcap.c: libpcap packet capture format
+ *
+ * Copyright (c) 2008 Eliot Dresselhaus
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <sys/fcntl.h>
+#include <vppinfra/pcap.h>
+
+/**
+ * @file
+ * @brief PCAP function.
+ *
+ * Usage:
+ *
+ * <code><pre>
+ * \#include <vppinfra/pcap.h>
+ *
+ * static pcap_main_t pcap = {
+ *  .file_name = "/tmp/ip4",
+ *  .n_packets_to_capture = 2,
+ *  .packet_type = PCAP_PACKET_TYPE_ip,
+ * };
+ * </pre></code>
+ *
+ * To add a buffer:
+ *
+ *  <code><pre>pcap_add_buffer (&pcap, vm, pi0, 128);</pre></code>
+ *
+ * File will be written after @c n_packets_to_capture or call to pcap_write (&amp;pcap).
+ *
+*/
+
+/**
+ * @brief Close PCAP file
+ *
+ * @return rc - clib_error_t
+ *
+ */
+clib_error_t *
+pcap_close (pcap_main_t * pm)
+{
+  close (pm->file_descriptor);
+  pm->flags &= ~PCAP_MAIN_INIT_DONE;
+  pm->file_descriptor = -1;
+  return 0;
+}
+
+/**
+ * @brief Write PCAP file
+ *
+ * @return rc - clib_error_t
+ *
+ */
+clib_error_t *
+pcap_write (pcap_main_t * pm)
+{
+  clib_error_t *error = 0;
+
+  if (!(pm->flags & PCAP_MAIN_INIT_DONE))
+    {
+      pcap_file_header_t fh;
+      int n;
+
+      if (!pm->file_name)
+	pm->file_name = "/tmp/vnet.pcap";
+
+      pm->file_descriptor =
+	open (pm->file_name, O_CREAT | O_TRUNC | O_WRONLY, 0664);
+      if (pm->file_descriptor < 0)
+	{
+	  error =
+	    clib_error_return_unix (0, "failed to open `%s'", pm->file_name);
+	  goto done;
+	}
+
+      pm->flags |= PCAP_MAIN_INIT_DONE;
+      pm->n_packets_captured = 0;
+      pm->n_pcap_data_written = 0;
+      clib_spinlock_init (&pm->lock);
+
+      /* Write file header. */
+      clib_memset (&fh, 0, sizeof (fh));
+      fh.magic = 0xa1b2c3d4;
+      fh.major_version = 2;
+      fh.minor_version = 4;
+      fh.time_zone = 0;
+      fh.max_packet_size_in_bytes = 1 << 16;
+      fh.packet_type = pm->packet_type;
+      n = write (pm->file_descriptor, &fh, sizeof (fh));
+      if (n != sizeof (fh))
+	{
+	  if (n < 0)
+	    error =
+	      clib_error_return_unix (0, "write file header `%s'",
+				      pm->file_name);
+	  else
+	    error =
+	      clib_error_return (0, "short write of file header `%s'",
+				 pm->file_name);
+	  goto done;
+	}
+    }
+
+  while (vec_len (pm->pcap_data) > pm->n_pcap_data_written)
+    {
+      int n = vec_len (pm->pcap_data) - pm->n_pcap_data_written;
+
+      n = write (pm->file_descriptor,
+		 vec_elt_at_index (pm->pcap_data, pm->n_pcap_data_written),
+		 n);
+
+      if (n < 0 && unix_error_is_fatal (errno))
+	{
+	  error = clib_error_return_unix (0, "write `%s'", pm->file_name);
+	  goto done;
+	}
+      pm->n_pcap_data_written += n;
+    }
+
+  if (pm->n_pcap_data_written >= vec_len (pm->pcap_data))
+    {
+      vec_reset_length (pm->pcap_data);
+      pm->n_pcap_data_written = 0;
+    }
+
+  if (pm->n_packets_captured >= pm->n_packets_to_capture)
+    pcap_close (pm);
+
+done:
+  if (error)
+    {
+      if (pm->file_descriptor >= 0)
+	close (pm->file_descriptor);
+    }
+  return error;
+}
+
+/**
+ * @brief Read PCAP file
+ *
+ * @return rc - clib_error_t
+ *
+ */
+clib_error_t *
+pcap_read (pcap_main_t * pm)
+{
+  clib_error_t *error = 0;
+  int fd, need_swap, n;
+  pcap_file_header_t fh;
+  pcap_packet_header_t ph;
+
+  fd = open (pm->file_name, O_RDONLY);
+  if (fd < 0)
+    {
+      error = clib_error_return_unix (0, "open `%s'", pm->file_name);
+      goto done;
+    }
+
+  if (read (fd, &fh, sizeof (fh)) != sizeof (fh))
+    {
+      error =
+	clib_error_return_unix (0, "read file header `%s'", pm->file_name);
+      goto done;
+    }
+
+  need_swap = 0;
+  if (fh.magic == 0xd4c3b2a1)
+    {
+      need_swap = 1;
+#define _(t,f) fh.f = clib_byte_swap_##t (fh.f);
+      foreach_pcap_file_header;
+#undef _
+    }
+
+  if (fh.magic != 0xa1b2c3d4)
+    {
+      error = clib_error_return (0, "bad magic `%s'", pm->file_name);
+      goto done;
+    }
+
+  pm->min_packet_bytes = 0;
+  pm->max_packet_bytes = 0;
+  while ((n = read (fd, &ph, sizeof (ph))) != 0)
+    {
+      u8 *data;
+      u64 timestamp;
+      u32 timestamp_sec;
+      u32 timestamp_usec;
+
+      if (need_swap)
+	{
+#define _(t,f) ph.f = clib_byte_swap_##t (ph.f);
+	  foreach_pcap_packet_header;
+#undef _
+	}
+
+      data = vec_new (u8, ph.n_bytes_in_packet);
+      if (read (fd, data, ph.n_packet_bytes_stored_in_file) !=
+	  ph.n_packet_bytes_stored_in_file)
+	{
+	  error = clib_error_return (0, "short read `%s'", pm->file_name);
+	  goto done;
+	}
+
+      if (vec_len (pm->packets_read) == 0)
+	pm->min_packet_bytes = pm->max_packet_bytes = ph.n_bytes_in_packet;
+      else
+	{
+	  pm->min_packet_bytes =
+	    clib_min (pm->min_packet_bytes, ph.n_bytes_in_packet);
+	  pm->max_packet_bytes =
+	    clib_max (pm->max_packet_bytes, ph.n_bytes_in_packet);
+	}
+
+      timestamp_sec = ph.time_in_sec;
+      timestamp_usec = ph.time_in_usec;
+      timestamp = ((u64) timestamp_sec) * 1000000 + (u64) timestamp_usec;
+      vec_add1 (pm->packets_read, data);
+      vec_add1 (pm->timestamps, timestamp);
+    }
+
+done:
+  if (fd >= 0)
+    close (fd);
+  return error;
+
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */