From 3ae2873e568dd441a22903ab9f8c7954835b0bf1 Mon Sep 17 00:00:00 2001 From: Dave Barach Date: Fri, 16 Nov 2018 17:19:00 -0500 Subject: [PATCH] pcap-based dispatch tracer To facilitate dispatch trajectory tracing, vlib_buffer_t decoding, etc. through Wireshark Change-Id: I31356b9fa1f40cba8830aaf10a86a9fbb7546438 Signed-off-by: Dave Barach --- src/plugins/cdp/cdp_periodic.c | 2 +- src/plugins/dpdk/device/dpdk.h | 2 +- src/vlib/main.c | 306 ++++++++++++++++++++++++++++++++++++- src/vlib/main.h | 5 + src/vlib/vlib.h | 2 +- src/vnet/CMakeLists.txt | 2 - src/vnet/devices/devices.h | 2 +- src/vnet/flow/flow.h | 2 +- src/vnet/interface.h | 3 +- src/vnet/pg/cli.c | 2 +- src/vnet/pg/pg.h | 2 +- src/vnet/unix/pcap2cinit.c | 2 +- src/vnet/unix/pcap2pg.c | 2 +- src/vnet/vnet.h | 2 +- src/vppinfra/CMakeLists.txt | 3 + src/{vnet/unix => vppinfra}/pcap.c | 4 +- src/{vnet/unix => vppinfra}/pcap.h | 119 +++++---------- src/vppinfra/pcap_funcs.h | 100 ++++++++++++ 18 files changed, 469 insertions(+), 93 deletions(-) rename src/{vnet/unix => vppinfra}/pcap.c (99%) rename src/{vnet/unix => vppinfra}/pcap.h (69%) create mode 100644 src/vppinfra/pcap_funcs.h diff --git a/src/plugins/cdp/cdp_periodic.c b/src/plugins/cdp/cdp_periodic.c index da08523176f..b0b33cf9d41 100644 --- a/src/plugins/cdp/cdp_periodic.c +++ b/src/plugins/cdp/cdp_periodic.c @@ -14,7 +14,7 @@ */ #include #include -#include +#include #include #include #include diff --git a/src/plugins/dpdk/device/dpdk.h b/src/plugins/dpdk/device/dpdk.h index 007a7b91905..0e5851dcbc6 100644 --- a/src/plugins/dpdk/device/dpdk.h +++ b/src/plugins/dpdk/device/dpdk.h @@ -44,7 +44,7 @@ #include #include -#include +#include #include #if CLIB_DEBUG > 0 diff --git a/src/vlib/main.c b/src/vlib/main.c index 964feb06c65..666b869915f 100644 --- a/src/vlib/main.c +++ b/src/vlib/main.c @@ -944,6 +944,84 @@ add_trajectory_trace (vlib_buffer_t * b, u32 node_index) #endif } +static void +dispatch_pcap_trace (vlib_main_t * vm, + vlib_node_runtime_t * node, vlib_frame_t * frame) +{ + int i; + vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **bufp, *b; + u8 name_tlv[64]; + pcap_main_t *pm = &vm->dispatch_pcap_main; + u32 capture_size; + vlib_node_t *n; + i32 n_left; + f64 time_now = vlib_time_now (vm); + u32 *from; + u32 name_length; + u8 *d; + + /* Input nodes don't have frames yet */ + if (frame == 0 || frame->n_vectors == 0) + return; + + from = vlib_frame_vector_args (frame); + vlib_get_buffers (vm, from, bufs, frame->n_vectors); + bufp = bufs; + + /* Create a node name TLV, since WS can't possibly guess */ + n = vlib_get_node (vm, node->node_index); + name_length = vec_len (n->name); + name_length = name_length < ARRAY_LEN (name_tlv) - 2 ? + name_length : ARRAY_LEN (name_tlv) - 2; + + name_tlv[0] = (u8) name_length; + clib_memcpy_fast (name_tlv + 1, n->name, name_length); + name_tlv[name_length + 1] = 0; + + for (i = 0; i < frame->n_vectors; i++) + { + if (PREDICT_TRUE (pm->n_packets_captured < pm->n_packets_to_capture)) + { + b = bufp[i]; + + /* Figure out how many bytes we're capturing */ + capture_size = (sizeof (vlib_buffer_t) - VLIB_BUFFER_PRE_DATA_SIZE) + vlib_buffer_length_in_chain (vm, b) + sizeof (u32) + +(name_length + 2); /* +2: count plus NULL byte */ + + clib_spinlock_lock_if_init (&pm->lock); + n_left = clib_min (capture_size, 512); + d = pcap_add_packet (pm, time_now, n_left, capture_size); + + /* Copy the buffer index */ + clib_memcpy_fast (d, &from[i], sizeof (u32)); + d += 4; + + /* Copy the name TLV */ + clib_memcpy_fast (d, name_tlv, name_length + 2); + d += name_length + 2; + + /* Copy the buffer metadata, but not the rewrite space */ + clib_memcpy_fast (d, b, sizeof (*b) - VLIB_BUFFER_PRE_DATA_SIZE); + d += sizeof (*b) - VLIB_BUFFER_PRE_DATA_SIZE; + + n_left = clib_min (vlib_buffer_length_in_chain (vm, b), + 512 - (sizeof (*b) - VLIB_BUFFER_PRE_DATA_SIZE)); + /* Copy the packet data */ + while (1) + { + u32 copy_length = clib_min ((u32) n_left, b->current_length); + clib_memcpy_fast (d, b->data + b->current_data, copy_length); + n_left -= b->current_length; + if (n_left <= 0) + break; + d += b->current_length; + ASSERT (b->flags & VLIB_BUFFER_NEXT_PRESENT); + b = vlib_get_buffer (vm, b->next_buffer); + } + clib_spinlock_unlock_if_init (&pm->lock); + } + } +} + static_always_inline u64 dispatch_node (vlib_main_t * vm, vlib_node_runtime_t * node, @@ -1020,10 +1098,16 @@ dispatch_node (vlib_main_t * vm, vlib_buffer_t *b = vlib_get_buffer (vm, from[i]); add_trajectory_trace (b, node->node_index); } + if (PREDICT_FALSE (vm->dispatch_pcap_enable)) + dispatch_pcap_trace (vm, node, frame); n = node->function (vm, node, frame); } else - n = node->function (vm, node, frame); + { + if (PREDICT_FALSE (vm->dispatch_pcap_enable)) + dispatch_pcap_trace (vm, node, frame); + n = node->function (vm, node, frame); + } t = clib_cpu_time_now (); @@ -1891,6 +1975,226 @@ done: return 0; } +static inline clib_error_t * +pcap_dispatch_trace_command_internal (vlib_main_t * vm, + unformat_input_t * input, + vlib_cli_command_t * cmd, int rx_tx) +{ +#define PCAP_DEF_PKT_TO_CAPTURE (100) + + unformat_input_t _line_input, *line_input = &_line_input; + pcap_main_t *pm = &vm->dispatch_pcap_main; + u8 *filename; + u8 *chroot_filename = 0; + u32 max = 0; + int enabled = 0; + int errorFlag = 0; + clib_error_t *error = 0; + + /* Get a line of input. */ + if (!unformat_user (input, unformat_line_input, line_input)) + return 0; + + while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT) + { + if (unformat (line_input, "on")) + { + if (vm->dispatch_pcap_enable == 0) + { + enabled = 1; + } + else + { + vlib_cli_output (vm, "pcap dispatch capture already on..."); + errorFlag = 1; + break; + } + } + else if (unformat (line_input, "off")) + { + if (vm->dispatch_pcap_enable) + { + vlib_cli_output + (vm, "captured %d pkts...", pm->n_packets_captured); + if (pm->n_packets_captured) + { + pm->n_packets_to_capture = pm->n_packets_captured; + error = pcap_write (pm); + if (error) + clib_error_report (error); + else + vlib_cli_output (vm, "saved to %s...", pm->file_name); + } + vm->dispatch_pcap_enable = 0; + } + else + { + vlib_cli_output (vm, "pcap tx capture already off..."); + errorFlag = 1; + break; + } + } + else if (unformat (line_input, "max %d", &max)) + { + if (vm->dispatch_pcap_enable) + { + vlib_cli_output + (vm, + "can't change max value while pcap tx capture active..."); + errorFlag = 1; + break; + } + pm->n_packets_to_capture = max; + } + else if (unformat (line_input, "file %s", &filename)) + { + if (vm->dispatch_pcap_enable) + { + vlib_cli_output + (vm, "can't change file while pcap tx capture active..."); + errorFlag = 1; + break; + } + + /* Brain-police user path input */ + if (strstr ((char *) filename, "..") + || index ((char *) filename, '/')) + { + vlib_cli_output (vm, "illegal characters in filename '%s'", + filename); + vlib_cli_output (vm, "Hint: .. and / are not allowed."); + vec_free (filename); + errorFlag = 1; + break; + } + + chroot_filename = format (0, "/tmp/%s%c", filename, 0); + vec_free (filename); + } + else if (unformat (line_input, "status")) + { + if (vm->dispatch_pcap_enable) + { + vlib_cli_output + (vm, "pcap dispatch capture is on: %d of %d pkts...", + pm->n_packets_captured, pm->n_packets_to_capture); + vlib_cli_output (vm, "Capture to file %s", pm->file_name); + } + else + { + vlib_cli_output (vm, "pcap dispatch capture is off..."); + } + break; + } + + else + { + error = clib_error_return (0, "unknown input `%U'", + format_unformat_error, line_input); + errorFlag = 1; + break; + } + } + unformat_free (line_input); + + + if (errorFlag == 0) + { + /* Since no error, save configured values. */ + if (chroot_filename) + { + if (pm->file_name) + vec_free (pm->file_name); + vec_add1 (chroot_filename, 0); + pm->file_name = (char *) chroot_filename; + } + + if (max) + pm->n_packets_to_capture = max; + + if (enabled) + { + if (pm->file_name == 0) + pm->file_name = (char *) format (0, "/tmp/dispatch.pcap%c", 0); + + pm->n_packets_captured = 0; + pm->packet_type = PCAP_PACKET_TYPE_user13; + if (pm->lock == 0) + clib_spinlock_init (&(pm->lock)); + vm->dispatch_pcap_enable = 1; + vlib_cli_output (vm, "pcap dispatch capture on..."); + } + } + else if (chroot_filename) + vec_free (chroot_filename); + + return error; +} + +static clib_error_t * +pcap_dispatch_trace_command_fn (vlib_main_t * vm, + unformat_input_t * input, + vlib_cli_command_t * cmd) +{ + return pcap_dispatch_trace_command_internal (vm, input, cmd, VLIB_RX); +} + +/*? + * This command is used to start or stop pcap dispatch trace capture, or show + * the capture status. + * + * This command has the following optional parameters: + * + * - on|off - Used to start or stop capture. + * + * - max - Depth of local buffer. Once 'nn' number + * of packets have been received, buffer is flushed to file. Once another + * 'nn' number of packets have been received, buffer is flushed + * to file, overwriting previous write. If not entered, value defaults + * to 100. Can only be updated if packet capture is off. + * + * - file - Used to specify the output filename. The file will + * be placed in the '/tmp' directory, so only the filename is + * supported. Directory should not be entered. If file already exists, file + * will be overwritten. If no filename is provided, '/tmp/vpe.pcap' + * will be used. Can only be updated if packet capture is off. + * + * - status - Displays the current status and configured attributes + * associated with a packet capture. If packet capture is in progress, + * 'status' also will return the number of packets currently in + * the local buffer. All additional attributes entered on command line + * with 'status' will be ignored and not applied. + * + * @cliexpar + * Example of how to display the status of capture when off: + * @cliexstart{pcap dispatch trace status} + * max is 100, for any interface to file /tmp/vpe.pcap + * pcap dispatch capture is off... + * @cliexend + * Example of how to start a dispatch trace capture: + * @cliexstart{pcap dispatch trace on max 35 file dispatchTrace.pcap} + * pcap dispatc capture on... + * @cliexend + * Example of how to display the status of a tx packet capture in progress: + * @cliexstart{pcap tx trace status} + * max is 35, dispatch trace to file /tmp/vppTest.pcap + * pcap tx capture is on: 20 of 35 pkts... + * @cliexend + * Example of how to stop a tx packet capture: + * @cliexstart{vppctl pcap dispatch trace off} + * captured 21 pkts... + * saved to /tmp/dispatchTrace.pcap... + * @cliexend +?*/ +/* *INDENT-OFF* */ +VLIB_CLI_COMMAND (pcap_dispatch_trace_command, static) = { + .path = "pcap dispatch trace", + .short_help = + "pcap dispatch trace [on|off] [max ] [file ] [status]", + .function = pcap_dispatch_trace_command_fn, +}; +/* *INDENT-ON* */ + /* * fd.io coding-style-patch-verification: ON * diff --git a/src/vlib/main.h b/src/vlib/main.h index 1cf8fe188b1..9e7538e9f00 100644 --- a/src/vlib/main.h +++ b/src/vlib/main.h @@ -47,6 +47,7 @@ #include #include #include +#include #include @@ -130,6 +131,10 @@ typedef struct vlib_main_t /* Packet trace buffer. */ vlib_trace_main_t trace_main; + /* Pcap dispatch trace main */ + pcap_main_t dispatch_pcap_main; + uword dispatch_pcap_enable; + /* Error handling. */ vlib_error_main_t error_main; diff --git a/src/vlib/vlib.h b/src/vlib/vlib.h index ba72f46aab2..49bb51bfbe3 100644 --- a/src/vlib/vlib.h +++ b/src/vlib/vlib.h @@ -73,8 +73,8 @@ struct vlib_main_t; #include #include #include - #include +#include #endif /* included_vlib_h */ diff --git a/src/vnet/CMakeLists.txt b/src/vnet/CMakeLists.txt index d7aa4a5a951..ac448e268b6 100644 --- a/src/vnet/CMakeLists.txt +++ b/src/vnet/CMakeLists.txt @@ -1143,14 +1143,12 @@ list(APPEND VNET_API_FILES feature/feature.api) list(APPEND VNET_SOURCES unix/gdb_funcs.c - unix/pcap.c unix/tap_api.c unix/tapcli.c unix/tuntap.c ) list(APPEND VNET_HEADERS - unix/pcap.h unix/tuntap.h unix/tapcli.h ) diff --git a/src/vnet/devices/devices.h b/src/vnet/devices/devices.h index cc960c98f23..d561563c295 100644 --- a/src/vnet/devices/devices.h +++ b/src/vnet/devices/devices.h @@ -16,7 +16,7 @@ #ifndef included_vnet_vnet_device_h #define included_vnet_vnet_device_h -#include +#include #include typedef enum diff --git a/src/vnet/flow/flow.h b/src/vnet/flow/flow.h index 19b6761474d..51cef7674a6 100644 --- a/src/vnet/flow/flow.h +++ b/src/vnet/flow/flow.h @@ -17,7 +17,7 @@ #define included_vnet_flow_flow_h #include -#include +#include #include #include #include diff --git a/src/vnet/interface.h b/src/vnet/interface.h index 061bd2ce4fa..f6f486e4591 100644 --- a/src/vnet/interface.h +++ b/src/vnet/interface.h @@ -40,7 +40,8 @@ #ifndef included_vnet_interface_h #define included_vnet_interface_h -#include +#include +#include #include struct vnet_main_t; diff --git a/src/vnet/pg/cli.c b/src/vnet/pg/cli.c index 13b0e97cf4c..8b543d3ca38 100644 --- a/src/vnet/pg/cli.c +++ b/src/vnet/pg/cli.c @@ -43,7 +43,7 @@ #include #ifdef CLIB_UNIX -#include +#include #endif /* Root of all packet generator cli commands. */ diff --git a/src/vnet/pg/pg.h b/src/vnet/pg/pg.h index ab3ae44aed6..99652b43981 100644 --- a/src/vnet/pg/pg.h +++ b/src/vnet/pg/pg.h @@ -43,7 +43,7 @@ #include /* for VLIB_N_RX_TX */ #include #include /* for buffer_fifo */ -#include +#include #include extern vnet_device_class_t pg_dev_class; diff --git a/src/vnet/unix/pcap2cinit.c b/src/vnet/unix/pcap2cinit.c index a81722e4062..5c159ebd555 100644 --- a/src/vnet/unix/pcap2cinit.c +++ b/src/vnet/unix/pcap2cinit.c @@ -19,7 +19,7 @@ * @brief Functions to convert PCAP file format to a u8 ** initializer * */ -#include +#include #include #include diff --git a/src/vnet/unix/pcap2pg.c b/src/vnet/unix/pcap2pg.c index 712907a5bac..e27dad7a412 100644 --- a/src/vnet/unix/pcap2pg.c +++ b/src/vnet/unix/pcap2pg.c @@ -19,7 +19,7 @@ * @brief Functions to convert PCAP file format to VPP PG (Packet Generator) * */ -#include +#include #include #include diff --git a/src/vnet/vnet.h b/src/vnet/vnet.h index 5098aa6ecec..9b2a8788752 100644 --- a/src/vnet/vnet.h +++ b/src/vnet/vnet.h @@ -42,7 +42,7 @@ #include -#include +#include #include #include #include diff --git a/src/vppinfra/CMakeLists.txt b/src/vppinfra/CMakeLists.txt index 6e1a4fd861a..4f0d16bd568 100644 --- a/src/vppinfra/CMakeLists.txt +++ b/src/vppinfra/CMakeLists.txt @@ -56,6 +56,7 @@ set(VPPINFRA_SRCS macros.c maplog.c mhash.c + pcap.c pmalloc.c pool.c ptclosure.c @@ -135,6 +136,8 @@ set(VPPINFRA_HEADERS mheap_bootstrap.h mheap.h os.h + pcap.h + pcap_funcs.h pipeline.h pmalloc.h pool.h diff --git a/src/vnet/unix/pcap.c b/src/vppinfra/pcap.c similarity index 99% rename from src/vnet/unix/pcap.c rename to src/vppinfra/pcap.c index 3c9ce314d9c..8f644e30f1d 100644 --- a/src/vnet/unix/pcap.c +++ b/src/vppinfra/pcap.c @@ -37,8 +37,8 @@ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ -#include #include +#include /** * @file @@ -47,7 +47,7 @@ * Usage: * *
- * \#include 
+ * \#include 
  *
  * static pcap_main_t pcap = {
  *  .file_name = "/tmp/ip4",
diff --git a/src/vnet/unix/pcap.h b/src/vppinfra/pcap.h
similarity index 69%
rename from src/vnet/unix/pcap.h
rename to src/vppinfra/pcap.h
index 0706aace496..5889a793401 100644
--- a/src/vnet/unix/pcap.h
+++ b/src/vppinfra/pcap.h
@@ -40,26 +40,63 @@
  * @file
  * @brief PCAP utility definitions
  */
-#ifndef included_vnet_pcap_h
-#define included_vnet_pcap_h
+#ifndef included_vppinfra_pcap_h
+#define included_vppinfra_pcap_h
 
-#include 
+#include 
+#include 
+#include 
+#include 
 
 /**
  * @brief Packet types supported by PCAP
  *
+ * These codes end up in the pcap file header.
+ * If you decide to build a wireshark dissector,
+ * you'll need to know that these codes are mapped
+ * through the pcap_to_wtap_map[] array in .../wiretap/pcap-common.c.
+ *
+ * For example:
+ *
+ *   { 160,		WTAP_ENCAP_USER13 },
+ *
+ * A file with (vpp) packet type PCAP_PACKET_TYPE_user13
+ * aka 160, will need a top-level dissector registered to
+ * deal with WTAP_ENCAP_USER13 [=58].
+ *
+ * Something like so:
+ *
+ * dissector_add_uint("wtap_encap", WTAP_ENCAP_USER13, vpp_dissector_handle);
+ *
  * null 0
  * ethernet 1
  * ppp 9
  * ip 12
  * hdlc 104
+ * user0 147 ... user15 162
  */
 #define foreach_vnet_pcap_packet_type           \
   _ (null, 0)					\
   _ (ethernet, 1)				\
   _ (ppp, 9)					\
   _ (ip, 12)					\
-  _ (hdlc, 104)
+  _ (hdlc, 104)                                 \
+  _ (user0,    147)                             \
+  _ (user1,    148)                             \
+  _ (user2,    149)                             \
+  _ (user3,    150)                             \
+  _ (user4,    151)                             \
+  _ (user5,    152)                             \
+  _ (user6,    153)                             \
+  _ (user7,    154)                             \
+  _ (user8,    155)                             \
+  _ (user9,    156)                             \
+  _ (user10,   157)                             \
+  _ (user11,   158)                             \
+  _ (user12,   159)                             \
+  _ (user13,   160)                             \
+  _ (user14,   161)                             \
+  _ (user15,   162)
 
 typedef enum
 {
@@ -161,79 +198,7 @@ typedef struct
   u32 min_packet_bytes, max_packet_bytes;
 } pcap_main_t;
 
-/** Write out data to output file. */
-clib_error_t *pcap_write (pcap_main_t * pm);
-
-/** Read data from file. */
-clib_error_t *pcap_read (pcap_main_t * pm);
-
-/**
- * @brief Add packet
- *
- * @param *pm - pcap_main_t
- * @param time_now - f64
- * @param n_bytes_in_trace - u32
- * @param n_bytes_in_packet - u32
- *
- * @return Packet Data
- *
- */
-static inline void *
-pcap_add_packet (pcap_main_t * pm,
-		 f64 time_now, u32 n_bytes_in_trace, u32 n_bytes_in_packet)
-{
-  pcap_packet_header_t *h;
-  u8 *d;
-
-  vec_add2 (pm->pcap_data, d, sizeof (h[0]) + n_bytes_in_trace);
-  h = (void *) (d);
-  h->time_in_sec = time_now;
-  h->time_in_usec = 1e6 * (time_now - h->time_in_sec);
-  h->n_packet_bytes_stored_in_file = n_bytes_in_trace;
-  h->n_bytes_in_packet = n_bytes_in_packet;
-  pm->n_packets_captured++;
-  return h->data;
-}
-
-/**
- * @brief Add buffer (vlib_buffer_t) to the trace
- *
- * @param *pm - pcap_main_t
- * @param *vm - vlib_main_t
- * @param buffer_index - u32
- * @param n_bytes_in_trace - u32
- *
- */
-static inline void
-pcap_add_buffer (pcap_main_t * pm,
-		 vlib_main_t * vm, u32 buffer_index, u32 n_bytes_in_trace)
-{
-  vlib_buffer_t *b = vlib_get_buffer (vm, buffer_index);
-  u32 n = vlib_buffer_length_in_chain (vm, b);
-  i32 n_left = clib_min (n_bytes_in_trace, n);
-  f64 time_now = vlib_time_now (vm);
-  void *d;
-
-  if (PREDICT_TRUE (pm->n_packets_captured < pm->n_packets_to_capture))
-    {
-      clib_spinlock_lock_if_init (&pm->lock);
-      d = pcap_add_packet (pm, time_now, n_left, n);
-      while (1)
-	{
-	  u32 copy_length = clib_min ((u32) n_left, b->current_length);
-	  clib_memcpy_fast (d, b->data + b->current_data, copy_length);
-	  n_left -= b->current_length;
-	  if (n_left <= 0)
-	    break;
-	  d += b->current_length;
-	  ASSERT (b->flags & VLIB_BUFFER_NEXT_PRESENT);
-	  b = vlib_get_buffer (vm, b->next_buffer);
-	}
-      clib_spinlock_unlock_if_init (&pm->lock);
-    }
-}
-
-#endif /* included_vnet_pcap_h */
+#endif /* included_vppinfra_pcap_h */
 
 /*
  * fd.io coding-style-patch-verification: ON
diff --git a/src/vppinfra/pcap_funcs.h b/src/vppinfra/pcap_funcs.h
new file mode 100644
index 00000000000..364f4be2333
--- /dev/null
+++ b/src/vppinfra/pcap_funcs.h
@@ -0,0 +1,100 @@
+/*
+ * 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.
+ */
+
+#ifndef included_vppinfra_pcap_funcs_h
+#define included_vppinfra_pcap_funcs_h
+
+/** Write out data to output file. */
+clib_error_t *pcap_write (pcap_main_t * pm);
+
+/** Read data from file. */
+clib_error_t *pcap_read (pcap_main_t * pm);
+
+/**
+ * @brief Add packet
+ *
+ * @param *pm - pcap_main_t
+ * @param time_now - f64
+ * @param n_bytes_in_trace - u32
+ * @param n_bytes_in_packet - u32
+ *
+ * @return Packet Data
+ *
+ */
+static inline void *
+pcap_add_packet (pcap_main_t * pm,
+		 f64 time_now, u32 n_bytes_in_trace, u32 n_bytes_in_packet)
+{
+  pcap_packet_header_t *h;
+  u8 *d;
+
+  vec_add2 (pm->pcap_data, d, sizeof (h[0]) + n_bytes_in_trace);
+  h = (void *) (d);
+  h->time_in_sec = time_now;
+  h->time_in_usec = 1e6 * (time_now - h->time_in_sec);
+  h->n_packet_bytes_stored_in_file = n_bytes_in_trace;
+  h->n_bytes_in_packet = n_bytes_in_packet;
+  pm->n_packets_captured++;
+  return h->data;
+}
+
+/**
+ * @brief Add buffer (vlib_buffer_t) to the trace
+ *
+ * @param *pm - pcap_main_t
+ * @param *vm - vlib_main_t
+ * @param buffer_index - u32
+ * @param n_bytes_in_trace - u32
+ *
+ */
+static inline void
+pcap_add_buffer (pcap_main_t * pm,
+		 struct vlib_main_t *vm, u32 buffer_index,
+		 u32 n_bytes_in_trace)
+{
+  vlib_buffer_t *b = vlib_get_buffer (vm, buffer_index);
+  u32 n = vlib_buffer_length_in_chain (vm, b);
+  i32 n_left = clib_min (n_bytes_in_trace, n);
+  f64 time_now = vlib_time_now (vm);
+  void *d;
+
+  if (PREDICT_TRUE (pm->n_packets_captured < pm->n_packets_to_capture))
+    {
+      clib_spinlock_lock_if_init (&pm->lock);
+      d = pcap_add_packet (pm, time_now, n_left, n);
+      while (1)
+	{
+	  u32 copy_length = clib_min ((u32) n_left, b->current_length);
+	  clib_memcpy_fast (d, b->data + b->current_data, copy_length);
+	  n_left -= b->current_length;
+	  if (n_left <= 0)
+	    break;
+	  d += b->current_length;
+	  ASSERT (b->flags & VLIB_BUFFER_NEXT_PRESENT);
+	  b = vlib_get_buffer (vm, b->next_buffer);
+	}
+      clib_spinlock_unlock_if_init (&pm->lock);
+    }
+}
+
+#endif /* included_vppinfra_pcap_funcs_h */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
-- 
2.16.6