Rework vpp connection based on vapi library

Change-Id: I3b41b4141fd7ef7577f4f2cc9193b9c623a9d6d7
Signed-off-by: Chuanguo Wang <wangchuanguo@huachentel.com>
Signed-off-by: Hongjun Ni <hongjun.ni@intel.com>

1 files changed, 699 insertions, 0 deletions

diff --git a/src/plugins/sc_interface.c b/src/plugins/sc_interface.c
new file mode 100644
index 0000000..41fd535
--- /dev/null
+++ b/src/plugins/sc_interface.c
@@ -0,0 +1,699 @@
+/*
+ * Copyright (c) 2016 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 <stdio.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include "sc_interface.h"
+#include <sysrepo.h>
+#include <sysrepo/plugins.h>
+#include <sysrepo/values.h>
+#include <sysrepo/xpath.h>
+#include <vnet/interface.h>
+#include <vapi/interface.api.vapi.h>
+
+DEFINE_VAPI_MSG_IDS_INTERFACE_API_JSON;
+
+/**
+ * @brief Helper function for converting netmask into prefix length.
+ */
+static uint8_t
+netmask_to_prefix(const char *netmask)
+{
+    in_addr_t n = 0;
+    uint8_t i = 0;
+
+    inet_pton(AF_INET, netmask, &n);
+
+    while (n > 0) {
+        n = n >> 1;
+        i++;
+    }
+
+    return i;
+}
+
+/**
+ * @brief Helper function for converting IPv4/IPv6 address string into binary representation.
+ */
+static void
+ip_addr_str_to_binary(const char *ip_address_str, uint8_t *ip_address_bin, bool is_ipv6)
+{
+    struct in6_addr addr6 = { 0, };
+    struct in_addr addr4 = { 0, };
+
+    if (is_ipv6) {
+        inet_pton(AF_INET6, ip_address_str, &(addr6));
+        memcpy(ip_address_bin, &addr6, sizeof(addr6));
+    } else {
+        inet_pton(AF_INET, ip_address_str, &(addr4));
+        memcpy(ip_address_bin, &addr4, sizeof(addr4));
+    }
+}
+
+/**
+ * @brief Enable or disable given interface.
+ */
+static int
+interface_enable_disable(const char *if_name, bool enable)
+{
+    uint32_t if_index = ~0;
+    int rc = 0;
+
+    SRP_LOG_DBG("%s interface '%s'", enable ? "Enabling" : "Disabling", if_name);
+
+    /* get interface index */
+    rc = sc_interface_name2index(if_name, &if_index);
+    if (0 != rc) {
+        SRP_LOG_ERR("Invalid interface name: %s", if_name);
+        return SR_ERR_INVAL_ARG;
+    }
+
+    /* enable/disable interface */
+    rc = sc_setInterfaceFlags(if_index, (uint8_t)enable);
+    if (0 != rc) {
+        SRP_LOG_ERR("Error by processing of the sw_interface_set_flags request, rc=%d", rc);
+        return SR_ERR_OPERATION_FAILED;
+    } else {
+        return SR_ERR_OK;
+    }
+}
+
+/**
+ * @brief Callback to be called by any config change of "/ietf-interfaces:interfaces/interface/enabled" leaf.
+ */
+static int
+sc_interface_enable_disable_cb(sr_session_ctx_t *session, const char *xpath, sr_notif_event_t event, void *private_ctx)
+{
+    char *if_name = NULL;
+    sr_change_iter_t *iter = NULL;
+    sr_change_oper_t op = SR_OP_CREATED;
+    sr_val_t *old_val = NULL;
+    sr_val_t *new_val = NULL;
+    sr_xpath_ctx_t xpath_ctx = { 0, };
+    int rc = SR_ERR_OK, op_rc = SR_ERR_OK;
+
+    /* no-op for apply, we only care about SR_EV_ENABLED, SR_EV_VERIFY, SR_EV_ABORT */
+    if (SR_EV_APPLY == event) {
+        return SR_ERR_OK;
+    }
+    SRP_LOG_DBG("'%s' modified, event=%d", xpath, event);
+
+    /* get changes iterator */
+    rc = sr_get_changes_iter(session, xpath, &iter);
+    if (SR_ERR_OK != rc) {
+        SRP_LOG_ERR("Unable to retrieve change iterator: %s", sr_strerror(rc));
+        return rc;
+    }
+
+    /* iterate over all changes */
+    while ((SR_ERR_OK == op_rc || event == SR_EV_ABORT) &&
+            (SR_ERR_OK == (rc = sr_get_change_next(session, iter, &op, &old_val, &new_val)))) {
+
+        SRP_LOG_DBG("A change detected in '%s', op=%d", new_val ? new_val->xpath : old_val->xpath, op);
+        if_name = sr_xpath_key_value(new_val ? new_val->xpath : old_val->xpath, "interface", "name", &xpath_ctx);
+        switch (op) {
+            case SR_OP_CREATED:
+            case SR_OP_MODIFIED:
+                op_rc = interface_enable_disable(if_name, new_val->data.bool_val);
+                break;
+            case SR_OP_DELETED:
+                op_rc = interface_enable_disable(if_name, false /* !enable */);
+                break;
+            default:
+                break;
+        }
+        sr_xpath_recover(&xpath_ctx);
+        if (SR_ERR_INVAL_ARG == op_rc) {
+            sr_set_error(session, "Invalid interface name.", new_val ? new_val->xpath : old_val->xpath);
+        }
+        sr_free_val(old_val);
+        sr_free_val(new_val);
+    }
+    sr_free_change_iter(iter);
+
+    return op_rc;
+}
+
+/**
+ * @brief Add or remove IPv4/IPv6 address to/from an interface.
+ */
+static int
+interface_ipv46_config_add_remove(const char *if_name, uint8_t *addr, uint8_t prefix, bool is_ipv6, bool add)
+{
+    uint32_t if_index = ~0;
+    int rc = 0;
+
+    SRP_LOG_DBG("%s IP config on interface '%s'.", add ? "Adding" : "Removing", if_name);
+
+    /* get interface index */
+    rc = sc_interface_name2index(if_name, &if_index);
+    if (0 != rc) {
+        SRP_LOG_ERR("Invalid interface name: %s", if_name);
+        return SR_ERR_INVAL_ARG;
+    }
+
+    /* add del addr */
+    rc = sc_interface_add_del_addr(if_index, (uint8_t)add, (uint8_t)is_ipv6, 0, prefix, addr);
+    if (0 != rc) {
+        SRP_LOG_ERR("Error by processing of the sw_interface_set_flags request, rc=%d", rc);
+        return SR_ERR_OPERATION_FAILED;
+    } else {
+        return SR_ERR_OK;
+    }
+}
+int sc_initSwInterfaceDumpCTX(sc_sw_interface_dump_ctx * dctx)
+{
+  if(dctx == NULL)
+    return -1;
+
+  dctx->intfcArray = NULL;
+  dctx->last_called = false;
+  dctx->capacity = 0;
+  dctx->num_ifs = 0;
+  return 0;
+}
+int sc_freeSwInterfaceDumpCTX(sc_sw_interface_dump_ctx * dctx)
+{
+  if(dctx == NULL)
+    return -1;
+
+  if(dctx->intfcArray != NULL)
+    {
+      printf("free intfcArray %p\n", dctx->intfcArray);
+      free(dctx->intfcArray);
+    }
+
+  return sc_initSwInterfaceDumpCTX(dctx);
+}
+vapi_error_e
+sc_sw_interface_dump_cb (struct vapi_ctx_s *ctx, void *callback_ctx,
+                      vapi_error_e rv, bool is_last,
+                      vapi_payload_sw_interface_details * reply)
+{
+  sc_sw_interface_dump_ctx *dctx = callback_ctx;
+  if (is_last)
+    {
+      dctx->last_called = true;
+    }
+  else
+    {
+      //printf ("Interface dump entry: [%u]: %s\n", reply->sw_if_index,
+      //              reply->interface_name);
+      if(dctx->capacity == 0 && dctx->intfcArray == NULL)
+        {
+          dctx->capacity = 10;
+          dctx->intfcArray = (scVppIntfc*)malloc( sizeof(scVppIntfc)*dctx->capacity );
+        }
+      if(dctx->num_ifs >= dctx->capacity-1)
+        {
+
+          dctx->capacity += 10;
+          dctx->intfcArray = (scVppIntfc*)realloc(dctx->intfcArray, sizeof(scVppIntfc)*dctx->capacity );
+        }
+
+      dctx->intfcArray[dctx->num_ifs].sw_if_index = reply->sw_if_index;
+      strncpy(dctx->intfcArray[dctx->num_ifs].interface_name, reply->interface_name, VPP_INTFC_NAME_LEN);
+      dctx->intfcArray[dctx->num_ifs].l2_address_length = reply->l2_address_length;
+      memcpy(dctx->intfcArray[dctx->num_ifs].l2_address, reply->l2_address, reply->l2_address_length );
+     //dctx->intfcArray[dctx->num_ifs].link_speed = reply->link_speed;
+#define ONE_MEGABIT (uint64_t)1000000
+      switch (reply->link_speed << VNET_HW_INTERFACE_FLAG_SPEED_SHIFT)
+        {
+        case VNET_HW_INTERFACE_FLAG_SPEED_10M:
+	  dctx->intfcArray[dctx->num_ifs].link_speed = 10 * ONE_MEGABIT;
+          break;
+        case VNET_HW_INTERFACE_FLAG_SPEED_100M:
+           dctx->intfcArray[dctx->num_ifs].link_speed = 100 * ONE_MEGABIT;
+          break;
+        case VNET_HW_INTERFACE_FLAG_SPEED_1G:
+	  dctx->intfcArray[dctx->num_ifs].link_speed = 1000 * ONE_MEGABIT;
+          break;
+        case VNET_HW_INTERFACE_FLAG_SPEED_2_5G:
+	  dctx->intfcArray[dctx->num_ifs].link_speed = 2500 * ONE_MEGABIT;
+          break;
+        case VNET_HW_INTERFACE_FLAG_SPEED_5G:
+	  dctx->intfcArray[dctx->num_ifs].link_speed = 5000 * ONE_MEGABIT;
+          break;
+        case VNET_HW_INTERFACE_FLAG_SPEED_10G:
+	  dctx->intfcArray[dctx->num_ifs].link_speed = 10000 * ONE_MEGABIT;
+          break;
+        case VNET_HW_INTERFACE_FLAG_SPEED_20G:
+	  dctx->intfcArray[dctx->num_ifs].link_speed = 20000 * ONE_MEGABIT;
+          break;
+        case VNET_HW_INTERFACE_FLAG_SPEED_25G:
+	  dctx->intfcArray[dctx->num_ifs].link_speed = 25000 * ONE_MEGABIT;
+          break;
+        case VNET_HW_INTERFACE_FLAG_SPEED_40G:
+	  dctx->intfcArray[dctx->num_ifs].link_speed = 40000 * ONE_MEGABIT;
+          break;
+        case VNET_HW_INTERFACE_FLAG_SPEED_50G:
+	  dctx->intfcArray[dctx->num_ifs].link_speed = 50000 * ONE_MEGABIT;
+          break;
+        case VNET_HW_INTERFACE_FLAG_SPEED_56G:
+	  dctx->intfcArray[dctx->num_ifs].link_speed = 56000 * ONE_MEGABIT;
+          break;
+        case VNET_HW_INTERFACE_FLAG_SPEED_100G:
+	  dctx->intfcArray[dctx->num_ifs].link_speed = 100000 * ONE_MEGABIT;
+          break;
+        default:
+          dctx->intfcArray[dctx->num_ifs].link_speed = 0;
+          break;
+        }
+
+        dctx->intfcArray[dctx->num_ifs].link_mtu = reply->link_mtu;
+        dctx->intfcArray[dctx->num_ifs].admin_up_down = reply->admin_up_down;
+        dctx->intfcArray[dctx->num_ifs].link_up_down = reply->link_up_down;
+
+      dctx->num_ifs += 1;
+    }
+  return VAPI_OK;
+}
+int sc_swInterfaceDump(sc_sw_interface_dump_ctx * dctx)
+{
+  if(dctx == NULL)
+    {
+      return -1;
+    }
+
+  //sc_sw_interface_dump_ctx dctx = { false, 0, 0, 0 };
+  vapi_msg_sw_interface_dump *dump;
+  vapi_error_e rv;
+  //  dctx->last_called = false;
+  sc_initSwInterfaceDumpCTX(dctx);
+  dump = vapi_alloc_sw_interface_dump (g_vapi_ctx_instance);
+  dump->payload.name_filter_valid = 0;
+  memset (dump->payload.name_filter, 0, sizeof (dump->payload.name_filter));
+  while (VAPI_EAGAIN ==
+         (rv =
+          vapi_sw_interface_dump (g_vapi_ctx_instance, dump, sc_sw_interface_dump_cb,
+                                  dctx)));
+
+  return dctx->num_ifs;
+}
+
+u32 sc_interface_name2index(const char *name, u32* if_index)
+{
+  u32 ret = -1;
+  sc_sw_interface_dump_ctx dctx = {false, 0, 0, 0};
+  vapi_msg_sw_interface_dump *dump;
+  vapi_error_e rv;
+  dctx.last_called = false;
+  dump = vapi_alloc_sw_interface_dump(g_vapi_ctx_instance);
+  dump->payload.name_filter_valid = 0;
+  memset(dump->payload.name_filter, 0, sizeof(dump->payload.name_filter));
+  while (VAPI_EAGAIN == (rv = vapi_sw_interface_dump(g_vapi_ctx_instance, dump, sc_sw_interface_dump_cb, &dctx)))
+    ;
+  printf("interface dump over, there are %d intfc\n", dctx.num_ifs);
+  int i = 0;
+  for (; i < dctx.num_ifs; ++i)
+  {
+    printf("Index[%d] %s\n", dctx.intfcArray[i].sw_if_index, dctx.intfcArray[i].interface_name);
+    if (strcmp(dctx.intfcArray[i].interface_name, name) == 0)
+    {
+      *if_index = dctx.intfcArray[i].sw_if_index;
+      ret = 0;
+      break;
+    }
+  }
+  sc_freeSwInterfaceDumpCTX(&dctx);
+
+  return ret;
+}
+
+i32 sc_interface_add_del_addr( u32 sw_if_index, u8 is_add, u8 is_ipv6, u8 del_all,
+			       u8 address_length, u8 address[VPP_IP6_ADDRESS_LEN] )
+{
+  i32 ret = -1;
+  vapi_msg_sw_interface_add_del_address *msg = vapi_alloc_sw_interface_add_del_address(g_vapi_ctx_instance);
+  msg->payload.sw_if_index = sw_if_index;
+  msg->payload.is_add = is_add;
+  msg->payload.is_ipv6 = is_ipv6;
+  msg->payload.del_all = del_all;
+  msg->payload.address_length = address_length;
+  memcpy(msg->payload.address, address, VPP_IP6_ADDRESS_LEN);
+  vapi_msg_sw_interface_add_del_address_hton (msg);
+
+  vapi_error_e rv = vapi_send (g_vapi_ctx_instance, msg);
+
+  vapi_msg_sw_interface_add_del_address_reply *resp;
+  
+  SC_VPP_VAPI_RECV;
+
+  vapi_msg_sw_interface_add_del_address_reply_hton(resp);
+  printf("addDelInterfaceAddr : %d \n", resp->payload.retval);
+  ret = resp->payload.retval;
+  vapi_msg_free (g_vapi_ctx_instance, resp);
+  return ret;
+}
+i32 sc_setInterfaceFlags(u32 sw_if_index, u8 admin_up_down)
+{
+  i32 ret = -1;
+  vapi_msg_sw_interface_set_flags *msg = vapi_alloc_sw_interface_set_flags(g_vapi_ctx_instance);
+  msg->payload.sw_if_index = sw_if_index;
+  msg->payload.admin_up_down = admin_up_down;
+  vapi_msg_sw_interface_set_flags_hton (msg);
+
+  vapi_error_e rv = vapi_send (g_vapi_ctx_instance, msg);
+
+  vapi_msg_sw_interface_set_flags_reply *resp;
+
+  SC_VPP_VAPI_RECV;
+
+  vapi_msg_sw_interface_set_flags_reply_ntoh(resp);
+  printf("setInterfaceFlags:%d \n", resp->payload.retval);
+  ret = resp->payload.retval;
+  vapi_msg_free (g_vapi_ctx_instance, resp);
+  return ret;
+}
+
+
+/**
+ * @brief Modify existing IPv4/IPv6 config on an interface.
+ */
+static int
+interface_ipv46_config_modify(sr_session_ctx_t *session, const char *if_name,
+        sr_val_t *old_val, sr_val_t *new_val, bool is_ipv6)
+{
+    sr_xpath_ctx_t xpath_ctx = { 0, };
+    char *addr_str = NULL;
+    uint8_t addr[16] = { 0, };
+    uint8_t prefix = 0;
+    int rc = SR_ERR_OK;
+
+    SRP_LOG_DBG("Updating IP config on interface '%s'.", if_name);
+
+    /* get old config to be deleted */
+    if (SR_UINT8_T == old_val->type) {
+        prefix = old_val->data.uint8_val;
+    } else if (SR_STRING_T == old_val->type) {
+        prefix = netmask_to_prefix(old_val->data.string_val);
+    } else {
+        return SR_ERR_INVAL_ARG;
+    }
+    addr_str = sr_xpath_key_value((char*)old_val->xpath, "address", "ip", &xpath_ctx);
+    ip_addr_str_to_binary(addr_str, addr, is_ipv6);
+    sr_xpath_recover(&xpath_ctx);
+
+    /* delete old IP config */
+    rc = interface_ipv46_config_add_remove(if_name, addr, prefix, is_ipv6, false /* remove */);
+    if (SR_ERR_OK != rc) {
+        SRP_LOG_ERR("Unable to remove old IP address config, rc=%d", rc);
+        return rc;
+    }
+
+    /* update the config with the new value */
+    if (sr_xpath_node_name_eq(new_val->xpath, "prefix-length")) {
+        prefix = new_val->data.uint8_val;
+    } else if (sr_xpath_node_name_eq(new_val->xpath, "netmask")) {
+        prefix = netmask_to_prefix(new_val->data.string_val);
+    }
+
+    /* set new IP config */
+    rc = interface_ipv46_config_add_remove(if_name, addr, prefix, is_ipv6, true /* add */);
+    if (SR_ERR_OK != rc) {
+        SRP_LOG_ERR("Unable to remove old IP address config, rc=%d", rc);
+        return rc;
+    }
+
+    return rc;
+}
+
+/**
+ * @brief Callback to be called by any config change in subtrees "/ietf-interfaces:interfaces/interface/ietf-ip:ipv4/address"
+ * or "/ietf-interfaces:interfaces/interface/ietf-ip:ipv6/address".
+ */
+static int
+sc_interface_ipv46_address_change_cb(sr_session_ctx_t *session, const char *xpath, sr_notif_event_t event, void *private_ctx)
+{
+    sr_change_iter_t *iter = NULL;
+    sr_change_oper_t op = SR_OP_CREATED;
+    sr_val_t *old_val = NULL;
+    sr_val_t *new_val = NULL;
+    sr_xpath_ctx_t xpath_ctx = { 0, };
+    bool is_ipv6 = false, has_addr = false, has_prefix = false;
+    uint8_t addr[16] = { 0, };
+    uint8_t prefix = 0;
+    char *node_name = NULL, *if_name = NULL;
+    int rc = SR_ERR_OK, op_rc = SR_ERR_OK;
+
+    /* no-op for apply, we only care about SR_EV_ENABLED, SR_EV_VERIFY, SR_EV_ABORT */
+    if (SR_EV_APPLY == event) {
+        return SR_ERR_OK;
+    }
+    SRP_LOG_DBG("'%s' modified, event=%d", xpath, event);
+
+    /* check whether we are handling ipv4 or ipv6 config */
+    node_name = sr_xpath_node_idx((char*)xpath, 2, &xpath_ctx);
+    if (NULL != node_name && 0 == strcmp(node_name, "ipv6")) {
+        is_ipv6 = true;
+    }
+    sr_xpath_recover(&xpath_ctx);
+
+    /* get changes iterator */
+    rc = sr_get_changes_iter(session, xpath, &iter);
+    if (SR_ERR_OK != rc) {
+        SRP_LOG_ERR("Unable to retrieve change iterator: %s", sr_strerror(rc));
+        return rc;
+    }
+
+    /* iterate over all changes */
+    while ((SR_ERR_OK == op_rc || event == SR_EV_ABORT) &&
+            (SR_ERR_OK == (rc = sr_get_change_next(session, iter, &op, &old_val, &new_val)))) {
+
+        SRP_LOG_DBG("A change detected in '%s', op=%d", new_val ? new_val->xpath : old_val->xpath, op);
+        if_name = strdup(sr_xpath_key_value(new_val ? new_val->xpath : old_val->xpath, "interface", "name", &xpath_ctx));
+        sr_xpath_recover(&xpath_ctx);
+
+        switch (op) {
+            case SR_OP_CREATED:
+                if (SR_LIST_T == new_val->type) {
+                    /* create on list item - reset state vars */
+                    has_addr = has_prefix = false;
+                } else {
+                    if (sr_xpath_node_name_eq(new_val->xpath, "ip")) {
+                        ip_addr_str_to_binary(new_val->data.string_val, addr, is_ipv6);
+                        has_addr = true;
+                    } else if (sr_xpath_node_name_eq(new_val->xpath, "prefix-length")) {
+                        prefix = new_val->data.uint8_val;
+                        has_prefix = true;
+                    } else if (sr_xpath_node_name_eq(new_val->xpath, "netmask")) {
+                        prefix = netmask_to_prefix(new_val->data.string_val);
+                        has_prefix = true;
+                    }
+                    if (has_addr && has_prefix) {
+                        op_rc = interface_ipv46_config_add_remove(if_name, addr, prefix, is_ipv6, true /* add */);
+                    }
+                }
+                break;
+            case SR_OP_MODIFIED:
+                op_rc = interface_ipv46_config_modify(session, if_name, old_val, new_val, is_ipv6);
+                break;
+            case SR_OP_DELETED:
+                if (SR_LIST_T == old_val->type) {
+                    /* delete on list item - reset state vars */
+                    has_addr = has_prefix = false;
+                } else {
+                    if (sr_xpath_node_name_eq(old_val->xpath, "ip")) {
+                        ip_addr_str_to_binary(old_val->data.string_val, addr, is_ipv6);
+                        has_addr = true;
+                    } else if (sr_xpath_node_name_eq(old_val->xpath, "prefix-length")) {
+                        prefix = old_val->data.uint8_val;
+                        has_prefix = true;
+                    } else if (sr_xpath_node_name_eq(old_val->xpath, "netmask")) {
+                        prefix = netmask_to_prefix(old_val->data.string_val);
+                        has_prefix = true;
+                    }
+                    if (has_addr && has_prefix) {
+                        op_rc = interface_ipv46_config_add_remove(if_name, addr, prefix, is_ipv6, false /* !add */);
+                    }
+                }
+                break;
+            default:
+                break;
+        }
+        if (SR_ERR_INVAL_ARG == op_rc) {
+            sr_set_error(session, "Invalid interface name.", new_val ? new_val->xpath : old_val->xpath);
+        }
+        free(if_name);
+        sr_free_val(old_val);
+        sr_free_val(new_val);
+    }
+    sr_free_change_iter(iter);
+
+    return op_rc;
+}
+
+/**
+ * @brief Callback to be called by any config change under "/ietf-interfaces:interfaces-state/interface" path.
+ * Does not provide any functionality, needed just to cover not supported config leaves.
+ */
+static int
+sc_interface_change_cb(sr_session_ctx_t *session, const char *xpath, sr_notif_event_t event, void *private_ctx)
+{
+    SRP_LOG_DBG("'%s' modified, event=%d", xpath, event);
+
+    return SR_ERR_OK;
+}
+
+/**
+ * @brief Callback to be called by any request for state data under "/ietf-interfaces:interfaces-state/interface" path.
+ */
+static int
+sc_interface_state_cb(const char *xpath, sr_val_t **values, size_t *values_cnt, void *private_ctx)
+{
+    sr_val_t *values_arr = NULL;
+    size_t values_arr_size = 0, values_arr_cnt = 0;
+    sc_sw_interface_dump_ctx dctx;
+    scVppIntfc* if_details;
+    int rc = 0;
+
+    SRP_LOG_DBG("Requesting state data for '%s'", xpath);
+printf("%d\n", __LINE__);
+    printf("Requesting state data for '%s'\n", xpath);
+
+    if (! sr_xpath_node_name_eq(xpath, "interface")) {
+        /* statistics, ipv4 and ipv6 state data not supported */
+      printf("============= you want %s ?\n ", xpath);
+      *values = NULL;
+      *values_cnt = 0;
+      return SR_ERR_OK;
+    }
+
+    /* dump interfaces */
+    rc = sc_swInterfaceDump(&dctx);
+    if (rc <= 0) {
+        SRP_LOG_ERR_MSG("Error by processing of a interface dump request.");
+	sc_freeSwInterfaceDumpCTX(&dctx);
+        return SR_ERR_INTERNAL;
+    }
+
+    /* allocate array of values to be returned */
+    values_arr_size = dctx.num_ifs * 5;
+    rc = sr_new_values(values_arr_size, &values_arr);
+    if (0 != rc) {
+      sc_freeSwInterfaceDumpCTX(&dctx);
+        return rc;
+    }
+    printf("create %d sr vals\n", values_arr_size);
+
+    size_t i = 0;
+    for (; i < dctx.num_ifs; i++) {
+        if_details = dctx.intfcArray+i;
+
+        /* currently the only supported interface types are propVirtual / ethernetCsmacd */
+        sr_val_build_xpath(&values_arr[values_arr_cnt], "%s[name='%s']/type", xpath, if_details->interface_name);
+        sr_val_set_str_data(&values_arr[values_arr_cnt], SR_IDENTITYREF_T,
+                strstr((char*)if_details->interface_name, "local0") ? "iana-if-type:propVirtual" : "iana-if-type:ethernetCsmacd");
+printf("\nset %s 's data\n",values_arr[values_arr_cnt].xpath);
+        values_arr_cnt++;
+
+        sr_val_build_xpath(&values_arr[values_arr_cnt], "%s[name='%s']/admin-status", xpath, if_details->interface_name);
+        sr_val_set_str_data(&values_arr[values_arr_cnt], SR_ENUM_T, if_details->admin_up_down ? "up" : "down");
+printf("\nset %s 's data\n",values_arr[values_arr_cnt].xpath);
+        values_arr_cnt++;
+
+        sr_val_build_xpath(&values_arr[values_arr_cnt], "%s[name='%s']/oper-status", xpath, if_details->interface_name);
+        sr_val_set_str_data(&values_arr[values_arr_cnt], SR_ENUM_T, if_details->link_up_down ? "up" : "down");
+printf("\nset %s 's data\n",values_arr[values_arr_cnt].xpath);
+        values_arr_cnt++;
+
+        if (if_details->l2_address_length > 0) {
+            sr_val_build_xpath(&values_arr[values_arr_cnt], "%s[name='%s']/phys-address", xpath, if_details->interface_name);
+            sr_val_build_str_data(&values_arr[values_arr_cnt], SR_STRING_T, "%02x:%02x:%02x:%02x:%02x:%02x",
+                    if_details->l2_address[0], if_details->l2_address[1], if_details->l2_address[2],
+                    if_details->l2_address[3], if_details->l2_address[4], if_details->l2_address[5]);
+printf("\nset %s 's data\n",values_arr[values_arr_cnt].xpath);
+            values_arr_cnt++;
+        } else {
+	  sr_val_build_xpath(&values_arr[values_arr_cnt], "%s[name='%s']/phys-address", xpath, if_details->interface_name);
+	  sr_val_build_str_data(&values_arr[values_arr_cnt], SR_STRING_T, "%02x:%02x:%02x:%02x:%02x:%02x", 0,0,0,0,0,0);
+	  printf("\nset %s 's data\n",values_arr[values_arr_cnt].xpath);
+	  values_arr_cnt++;
+	}
+
+        sr_val_build_xpath(&values_arr[values_arr_cnt], "%s[name='%s']/speed", xpath, if_details->interface_name);
+        values_arr[values_arr_cnt].type = SR_UINT64_T;
+        values_arr[values_arr_cnt].data.uint64_val = if_details->link_speed;
+printf("\nset %s 's data\n",values_arr[values_arr_cnt].xpath);
+        values_arr_cnt++;
+    }
+
+    SRP_LOG_DBG("Returning %zu state data elements for '%s'", values_arr, xpath);
+    printf("\nReturning %d  data elements for '%s'\n", values_arr_cnt, xpath);
+
+    *values = values_arr;
+    *values_cnt = values_arr_cnt;
+
+    sc_freeSwInterfaceDumpCTX(&dctx);
+
+    return SR_ERR_OK;
+}
+
+/**
+ * @brief Callback to be called by plugin daemon upon plugin load.
+ */
+int
+sc_interface_subscribe_events(sr_session_ctx_t *session,
+			      sr_subscription_ctx_t **subscription)
+{
+    int rc = SR_ERR_OK;
+
+    SRP_LOG_DBG_MSG("Initializing vpp-interfaces plugin.");
+
+    rc = sr_subtree_change_subscribe(session, "/ietf-interfaces:interfaces/interface",
+            sc_interface_change_cb, g_vapi_ctx_instance, 0, SR_SUBSCR_CTX_REUSE | SR_SUBSCR_EV_ENABLED, subscription);
+    if (SR_ERR_OK != rc) {
+        goto error;
+    }
+
+    rc = sr_subtree_change_subscribe(session, "/ietf-interfaces:interfaces/interface/enabled",
+            sc_interface_enable_disable_cb, g_vapi_ctx_instance, 100, SR_SUBSCR_CTX_REUSE | SR_SUBSCR_EV_ENABLED, subscription);
+    if (SR_ERR_OK != rc) {
+        goto error;
+    }
+
+    rc = sr_subtree_change_subscribe(session, "/ietf-interfaces:interfaces/interface/ietf-ip:ipv4/address",
+            sc_interface_ipv46_address_change_cb, g_vapi_ctx_instance, 99, SR_SUBSCR_CTX_REUSE | SR_SUBSCR_EV_ENABLED, subscription);
+    if (SR_ERR_OK != rc) {
+        goto error;
+    }
+
+    rc = sr_subtree_change_subscribe(session, "/ietf-interfaces:interfaces/interface/ietf-ip:ipv6/address",
+            sc_interface_ipv46_address_change_cb, g_vapi_ctx_instance, 98, SR_SUBSCR_CTX_REUSE | SR_SUBSCR_EV_ENABLED, subscription);
+    if (SR_ERR_OK != rc) {
+        goto error;
+    }
+
+    rc = sr_dp_get_items_subscribe(session, "/ietf-interfaces:interfaces-state",
+				   sc_interface_state_cb, g_vapi_ctx_instance, SR_SUBSCR_DEFAULT/*SR_SUBSCR_CTX_REUSE*/, subscription);
+    if (SR_ERR_OK != rc) {
+        goto error;
+    }
+
+
+    SRP_LOG_INF_MSG("vpp-interfaces plugin initialized successfully.");
+    printf("vpp-interfaces plugin initialized successfully.\n");
+
+    return SR_ERR_OK;
+
+error:
+    SRP_LOG_ERR_MSG("Error by initialization of the sc_interfaces plugin.");
+    sr_plugin_cleanup_cb(session, g_vapi_ctx_instance);
+    return rc;
+}
+