sr: Add support for SRv6 Path Tracing Infrastructure

This patch adds support for the infrastructure
required to support SRv6 Path Tracing defined in
https://datatracker.ietf.org/doc/draft-filsfils-spring-path-tracing/

Type: feature

Change-Id: If3b09d6216490a60dd5a816577477b6399abc124
Signed-off-by: Ahmed Abdelsalam <ahabdels@cisco.com>

4 files changed, 350 insertions, 0 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index e24d077b540..444871ce7ea 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -180,6 +180,7 @@ F:	src/vnet/pg/
 VNET Segment Routing (IPv6 and MPLS)
 I:	sr
 M:	Pablo Camarillo <pcamaril@cisco.com>
+M:	Ahmed Abdelsalam <ahabdels@cisco.com>
 F:	src/vnet/srv6/
 F:	src/vnet/srmpls/
 F:	src/examples/srv6-sample-localsid/
diff --git a/src/vnet/CMakeLists.txt b/src/vnet/CMakeLists.txt
index 1cd5b58f85a..3c9ae80162c 100644
--- a/src/vnet/CMakeLists.txt
+++ b/src/vnet/CMakeLists.txt
@@ -817,11 +817,13 @@ list(APPEND VNET_SOURCES
   srv6/sr_policy_rewrite.c
   srv6/sr_steering.c
   srv6/sr_api.c
+  srv6/sr_pt.c
 )
 
 list(APPEND VNET_HEADERS
   srv6/sr_packet.h
   srv6/sr.h
+  srv6/sr_pt.h
 )
 
 list(APPEND VNET_API_FILES
diff --git a/src/vnet/srv6/sr_pt.c b/src/vnet/srv6/sr_pt.c
new file mode 100644
index 00000000000..28da12e22f4
--- /dev/null
+++ b/src/vnet/srv6/sr_pt.c
@@ -0,0 +1,279 @@
+/* SPDX-License-Identifier: Apache-2.0
+ * Copyright(c) 2022 Cisco Systems, Inc.
+ */
+
+/**
+ * @file
+ * @brief SR Path Tracing (PT)
+ *
+ * PT CLI
+ *
+ */
+
+#include <vlib/vlib.h>
+#include <vnet/vnet.h>
+#include <vnet/srv6/sr.h>
+#include <vnet/ip/ip.h>
+#include <vnet/srv6/sr_packet.h>
+#include <vnet/ip/ip6_packet.h>
+#include <vnet/fib/ip6_fib.h>
+#include <vnet/dpo/dpo.h>
+#include <vnet/adj/adj.h>
+#include <vnet/srv6/sr_pt.h>
+
+#include <vppinfra/error.h>
+#include <vppinfra/elog.h>
+
+sr_pt_main_t sr_pt_main;
+
+void *
+sr_pt_find_iface (u32 iface)
+{
+  sr_pt_main_t *sr_pt = &sr_pt_main;
+  uword *p;
+
+  /* Search for the item */
+  p = mhash_get (&sr_pt->sr_pt_iface_index_hash, &iface);
+  if (p)
+    {
+      /* Retrieve pt_iface */
+      return pool_elt_at_index (sr_pt->sr_pt_iface, p[0]);
+    }
+  return NULL;
+}
+
+int
+sr_pt_add_iface (u32 iface, u16 id, u8 ingress_load, u8 egress_load,
+		 u8 tts_template)
+{
+  sr_pt_main_t *sr_pt = &sr_pt_main;
+  uword *p;
+
+  sr_pt_iface_t *ls = 0;
+
+  if (iface == (u32) ~0)
+    return SR_PT_ERR_IFACE_INVALID;
+
+  /* Search for the item */
+  p = mhash_get (&sr_pt->sr_pt_iface_index_hash, &iface);
+
+  if (p)
+    return SR_PT_ERR_EXIST;
+
+  if (id > SR_PT_ID_MAX)
+    return SR_PT_ERR_ID_INVALID;
+
+  if (ingress_load > SR_PT_LOAD_MAX || egress_load > SR_PT_LOAD_MAX)
+    return SR_PT_ERR_LOAD_INVALID;
+
+  if (tts_template > SR_PT_TTS_TEMPLATE_MAX)
+    return SR_PT_ERR_TTS_TEMPLATE_INVALID;
+
+  /* Create a new pt_iface */
+  pool_get (sr_pt->sr_pt_iface, ls);
+  clib_memset (ls, 0, sizeof (*ls));
+  ls->iface = iface;
+  ls->id = id;
+  ls->ingress_load = ingress_load;
+  ls->egress_load = egress_load;
+  ls->tts_template = tts_template;
+
+  /* Set hash key for searching pt_iface by iface */
+  mhash_set (&sr_pt->sr_pt_iface_index_hash, &iface, ls - sr_pt->sr_pt_iface,
+	     NULL);
+  return 0;
+}
+
+int
+sr_pt_del_iface (u32 iface)
+{
+  sr_pt_main_t *sr_pt = &sr_pt_main;
+  uword *p;
+
+  sr_pt_iface_t *ls = 0;
+
+  if (iface == (u32) ~0)
+    return SR_PT_ERR_IFACE_INVALID;
+
+  /* Search for the item */
+  p = mhash_get (&sr_pt->sr_pt_iface_index_hash, &iface);
+
+  if (p)
+    {
+      /* Retrieve sr_pt_iface */
+      ls = pool_elt_at_index (sr_pt->sr_pt_iface, p[0]);
+      /* Delete sr_pt_iface */
+      pool_put (sr_pt->sr_pt_iface, ls);
+      mhash_unset (&sr_pt->sr_pt_iface_index_hash, &iface, NULL);
+    }
+  else
+    {
+      return SR_PT_ERR_NOENT;
+    }
+  return 0;
+}
+
+/**
+ * @brief "sr pt add iface" CLI function.
+ *
+ * @see sr_pt_add_iface
+ */
+static clib_error_t *
+sr_pt_add_iface_command_fn (vlib_main_t *vm, unformat_input_t *input,
+			    vlib_cli_command_t *cmd)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  u32 iface = (u32) ~0;
+  u32 id = (u32) ~0;
+  u32 ingress_load = 0;
+  u32 egress_load = 0;
+  u32 tts_template = SR_PT_TTS_TEMPLATE_DEFAULT;
+
+  int rv;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "%U", unformat_vnet_sw_interface, vnm, &iface))
+	;
+      else if (unformat (input, "id %u", &id))
+	;
+      else if (unformat (input, "ingress-load %u", &ingress_load))
+	;
+      else if (unformat (input, "egress-load %u", &egress_load))
+	;
+      else if (unformat (input, "tts-template %u", &tts_template))
+	;
+      else
+	break;
+    }
+
+  rv = sr_pt_add_iface (iface, id, ingress_load, egress_load, tts_template);
+
+  switch (rv)
+    {
+    case 0:
+      break;
+    case SR_PT_ERR_EXIST:
+      return clib_error_return (0, "Error: Identical iface already exists.");
+    case SR_PT_ERR_IFACE_INVALID:
+      return clib_error_return (0, "Error: The iface name invalid.");
+    case SR_PT_ERR_ID_INVALID:
+      return clib_error_return (0, "Error: The iface id value invalid.");
+    case SR_PT_ERR_LOAD_INVALID:
+      return clib_error_return (
+	0, "Error: The iface ingress or egress load value invalid.");
+    case SR_PT_ERR_TTS_TEMPLATE_INVALID:
+      return clib_error_return (
+	0, "Error: The iface TTS Template value invalid.");
+    default:
+      return clib_error_return (0, "Error: unknown error.");
+    }
+  return 0;
+}
+
+/**
+ * @brief "sr pt del iface" CLI function.
+ *
+ * @see sr_pt_del_iface
+ */
+static clib_error_t *
+sr_pt_del_iface_command_fn (vlib_main_t *vm, unformat_input_t *input,
+			    vlib_cli_command_t *cmd)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  u32 iface = (u32) ~0;
+
+  int rv;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "%U", unformat_vnet_sw_interface, vnm, &iface))
+	;
+      else
+	break;
+    }
+
+  rv = sr_pt_del_iface (iface);
+
+  switch (rv)
+    {
+    case 0:
+      break;
+    case SR_PT_ERR_NOENT:
+      return clib_error_return (0, "Error: No such iface.");
+    case SR_PT_ERR_IFACE_INVALID:
+      return clib_error_return (0, "Error: The iface name is not valid.");
+    default:
+      return clib_error_return (0, "Error: unknown error.");
+    }
+  return 0;
+}
+
+/**
+ * @brief CLI function to show all PT interfcaes
+ */
+static clib_error_t *
+sr_pt_show_iface_command_fn (vlib_main_t *vm, unformat_input_t *input,
+			     vlib_cli_command_t *cmd)
+{
+  vnet_main_t *vnm = vnet_get_main ();
+  sr_pt_main_t *sr_pt = &sr_pt_main;
+  sr_pt_iface_t **sr_pt_iface_list = 0;
+  sr_pt_iface_t *ls;
+  int i;
+
+  vlib_cli_output (vm, "SR PT Interfaces");
+  vlib_cli_output (vm, "==================================");
+
+  pool_foreach (ls, sr_pt->sr_pt_iface)
+    {
+      vec_add1 (sr_pt_iface_list, ls);
+    };
+
+  for (i = 0; i < vec_len (sr_pt_iface_list); i++)
+    {
+      ls = sr_pt_iface_list[i];
+      vlib_cli_output (
+	vm,
+	"\tiface       : \t%U\n\tid          : \t%d\n\tingress-load: "
+	"\t%d\n\tegress-load : \t%d\n\ttts-template: \t%d  ",
+	format_vnet_sw_if_index_name, vnm, ls->iface, ls->id, ls->ingress_load,
+	ls->egress_load, ls->tts_template);
+      vlib_cli_output (vm, "--------------------------------");
+    }
+
+  return 0;
+}
+
+VLIB_CLI_COMMAND (sr_pt_add_iface_command, static) = {
+  .path = "sr pt add iface",
+  .short_help = "sr pt add iface <iface-name> id <pt-iface-id> ingress-load "
+		"<ingress-load-value> egress-load <egress-load-value> "
+		"tts-template <tts-template-value>",
+  .function = sr_pt_add_iface_command_fn,
+};
+
+VLIB_CLI_COMMAND (sr_pt_del_iface_command, static) = {
+  .path = "sr pt del iface",
+  .short_help = "sr pt del iface <iface-name>",
+  .function = sr_pt_del_iface_command_fn,
+};
+
+VLIB_CLI_COMMAND (sr_pt_show_iface_command, static) = {
+  .path = "sr pt show iface",
+  .short_help = "sr pt show iface",
+  .function = sr_pt_show_iface_command_fn,
+};
+
+/**
+ *  * @brief SR PT initialization
+ *   */
+clib_error_t *
+sr_pt_init (vlib_main_t *vm)
+{
+  sr_pt_main_t *pt = &sr_pt_main;
+  mhash_init (&pt->sr_pt_iface_index_hash, sizeof (uword), sizeof (u32));
+  return 0;
+}
+
+VLIB_INIT_FUNCTION (sr_pt_init);
\ No newline at end of file
diff --git a/src/vnet/srv6/sr_pt.h b/src/vnet/srv6/sr_pt.h
new file mode 100644
index 00000000000..7242f90b6b3
--- /dev/null
+++ b/src/vnet/srv6/sr_pt.h
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: Apache-2.0
+ * Copyright(c) 2022 Cisco Systems, Inc.
+ */
+
+/**
+ * @file
+ * @brief SR Path Tracing data structures definitions
+ *
+ */
+
+#ifndef included_vnet_sr_pt_h
+#define included_vnet_sr_pt_h
+
+/*PT error codes*/
+#define SR_PT_ERR_NOENT		       -1 /* No such entry*/
+#define SR_PT_ERR_EXIST		       -2 /* Entry exists */
+#define SR_PT_ERR_IFACE_INVALID	       -3 /* IFACE invalid */
+#define SR_PT_ERR_ID_INVALID	       -4 /* ID invalid */
+#define SR_PT_ERR_LOAD_INVALID	       -5 /* LOAD invalid*/
+#define SR_PT_ERR_TTS_TEMPLATE_INVALID -6 /* TTS Template invalid */
+
+/*PT paramters max values*/
+#define SR_PT_ID_MAX	       4095
+#define SR_PT_LOAD_MAX	       15
+#define SR_PT_TTS_TEMPLATE_MAX 3
+
+/*PT TTS Templates*/
+#define SR_PT_TTS_TEMPLATE_0	   0
+#define SR_PT_TTS_TEMPLATE_1	   1
+#define SR_PT_TTS_TEMPLATE_2	   2
+#define SR_PT_TTS_TEMPLATE_3	   3
+#define SR_PT_TTS_TEMPLATE_DEFAULT 2
+
+/*PT TTS Template shift value*/
+#define SR_PT_TTS_SHIFT_TEMPLATE_0 8
+#define SR_PT_TTS_SHIFT_TEMPLATE_1 12
+#define SR_PT_TTS_SHIFT_TEMPLATE_2 16
+#define SR_PT_TTS_SHIFT_TEMPLATE_3 20
+
+typedef struct
+{
+  u32 iface;	   /**< Interface */
+  u16 id;	   /**< Interface ID */
+  u8 ingress_load; /**< Interface Ingress Load */
+  u8 egress_load;  /**< Interface Egress Load */
+  u8 tts_template; /**< Interface TTS Template */
+} sr_pt_iface_t;
+
+/**
+ * @brief Path Tracing main datastructure
+ */
+typedef struct
+{
+  /* Pool of pt_iface instances */
+  sr_pt_iface_t *sr_pt_iface;
+
+  /* Hash table for pt iface parameters */
+  mhash_t sr_pt_iface_index_hash;
+
+} sr_pt_main_t;
+
+extern sr_pt_main_t sr_pt_main;
+extern int sr_pt_add_iface (u32 iface, u16 id, u8 ingress_load, u8 egress_load,
+			    u8 tts_template);
+extern int sr_pt_del_iface (u32 iface);
+extern void *sr_pt_find_iface (u32 iface);
+
+#endif /* included_vnet_sr_pt_h */