snmp/snmp_private_mib/lwip_prvmib.c

/**
 * @file
 * lwip Private MIB
 *
 * @todo create MIB file for this example
 * @note the lwip enterprise tree root (26381) is owned by the lwIP project.
 * It is NOT allowed to allocate new objects under this ID (26381) without our,
 * the lwip developers, permission!
 *
 * Please apply for your own ID with IANA: http://www.iana.org/numbers.html
 *
 * lwip        OBJECT IDENTIFIER ::= { enterprises 26381 }
 * example     OBJECT IDENTIFIER ::= { lwip 1 }
 */

/*
 * Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * Author: Christiaan Simons <christiaan.simons@axon.tv>
 */

#include "private_mib.h"

#if LWIP_SNMP

/** Directory where the sensor files are */
#define SENSORS_DIR           "w:\\sensors"
/** Set to 1 to read sensor values from files (in directory defined by SENSORS_DIR) */
#define SENSORS_USE_FILES     0
/** Set to 1 to search sensor files at startup (in directory defined by SENSORS_DIR) */
#define SENSORS_SEARCH_FILES  0

#if SENSORS_SEARCH_FILES
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <dirent.h>
#endif /* SENSORS_SEARCH_FILES */

#include <string.h>
#include <stdio.h>

#include "lwip/apps/snmp_table.h"
#include "lwip/apps/snmp_scalar.h"

#if !SENSORS_USE_FILES || !SENSORS_SEARCH_FILES
/** When not using & searching files, defines the number of sensors */
#define SENSOR_COUNT 4
#endif /* !SENSORS_USE_FILES || !SENSORS_SEARCH_FILES */

/*
  This example presents a table for a few (at most 10) sensors.
  Sensor detection takes place at initialization (once only).
  Sensors may and can not be added or removed after agent
  has started. Note this is only a limitation of this crude example,
  the agent does support dynamic object insertions and removals.

  You'll need to manually create a directory called "sensors" and
  a few single line text files with an integer temperature value.
  The files must be called [0..9].txt.

  ./sensors/0.txt [content: 20]
  ./sensors/3.txt [content: 75]

  The sensor values may be changed in runtime by editing the
  text files in the "sensors" directory.
*/

#define SENSOR_MAX      10
#define SENSOR_NAME_LEN 20

struct sensor_inf
{
  u8_t num;

  char file[SENSOR_NAME_LEN + 1];

#if !SENSORS_USE_FILES
  /** When not using files, contains the value of the sensor */
  s32_t value;
#endif /* !SENSORS_USE_FILES */
};

static struct sensor_inf sensors[SENSOR_MAX];

static s16_t      sensor_count_get_value(struct snmp_node_instance* instance, void* value);
static snmp_err_t sensor_table_get_cell_instance(const u32_t* column, const u32_t* row_oid, u8_t row_oid_len, struct snmp_node_instance* cell_instance);
static snmp_err_t sensor_table_get_next_cell_instance(const u32_t* column, struct snmp_obj_id* row_oid, struct snmp_node_instance* cell_instance);
static s16_t      sensor_table_get_value(struct snmp_node_instance* instance, void* value);
static snmp_err_t sensor_table_set_value(struct snmp_node_instance* instance, u16_t len, void *value);

/* sensorentry .1.3.6.1.4.1.26381.1.1.1 (.level0.level1)
   where level 0 is the table column (temperature/file name)
   and level 1 the table row (sensor index) */
static const struct snmp_table_col_def sensor_table_columns[] = {
  { 1, SNMP_ASN1_TYPE_INTEGER,      SNMP_NODE_INSTANCE_READ_WRITE },
  { 2, SNMP_ASN1_TYPE_OCTET_STRING, SNMP_NODE_INSTANCE_READ_ONLY  }
};

/* sensortable .1.3.6.1.4.1.26381.1.1 */
static const struct snmp_table_node sensor_table = SNMP_TABLE_CREATE(
  1, sensor_table_columns,
  sensor_table_get_cell_instance, sensor_table_get_next_cell_instance,
  sensor_table_get_value, snmp_set_test_ok, sensor_table_set_value);

/* sensorcount .1.3.6.1.4.1.26381.1.2 */
static const struct snmp_scalar_node sensor_count = SNMP_SCALAR_CREATE_NODE_READONLY(
  2, SNMP_ASN1_TYPE_INTEGER, sensor_count_get_value);

/* example .1.3.6.1.4.1.26381.1 */
static const struct snmp_node* const example_nodes[] = {
  &sensor_table.node.node,
  &sensor_count.node.node
};
static const struct snmp_tree_node example_node = SNMP_CREATE_TREE_NODE(1, example_nodes);

static const u32_t prvmib_base_oid[] = { 1,3,6,1,4,1,26381,1 };
const struct snmp_mib mib_private = SNMP_MIB_CREATE(prvmib_base_oid, &example_node.node);

#if 0
/* for reference: we could also have expressed it like this: */

/* lwip .1.3.6.1.4.1.26381 */
static const struct snmp_node* const lwip_nodes[] = {
  &example_node.node
};
static const struct snmp_tree_node lwip_node = SNMP_CREATE_TREE_NODE(26381, lwip_nodes);

/* enterprises .1.3.6.1.4.1 */
static const struct snmp_node* const enterprises_nodes[] = {
  &lwip_node.node
};
static const struct snmp_tree_node enterprises_node = SNMP_CREATE_TREE_NODE(1, enterprises_nodes);

/* private .1.3.6.1.4 */
static const struct snmp_node* const private_nodes[] = {
  &enterprises_node.node
};
static const struct snmp_tree_node private_root = SNMP_CREATE_TREE_NODE(4, private_nodes);

static const u32_t prvmib_base_oid[] = { 1,3,6,1,4 };
const struct snmp_mib mib_private = SNMP_MIB_CREATE(prvmib_base_oid, &private_root.node);
#endif

/**
 * Initialises this private MIB before use.
 * @see main.c
 */
void
lwip_privmib_init(void)
{
#if SENSORS_USE_FILES && SENSORS_SEARCH_FILES
  char *buf, *ebuf, *cp;
  size_t bufsize;
  int nbytes;
  struct stat sb;
  struct dirent *dp;
  int fd;
#else /* SENSORS_USE_FILES && SENSORS_SEARCH_FILES */
  u8_t i;
#endif /* SENSORS_USE_FILES && SENSORS_SEARCH_FILES */

  memset(sensors, 0, sizeof(sensors));

  printf("SNMP private MIB start, detecting sensors.\n");

#if SENSORS_USE_FILES && SENSORS_SEARCH_FILES
  /* look for sensors in sensors directory */
  fd = open(SENSORS_DIR, O_RDONLY);
  if (fd > -1)
  {
    fstat(fd, &sb);
    bufsize = sb.st_size;
    if (bufsize < (size_t)sb.st_blksize)
    {
      bufsize = sb.st_blksize;
    }
    buf = (char*)malloc(bufsize);
    if (buf != NULL)
    {
      do
      {
        long base;

        nbytes = getdirentries(fd, buf, bufsize, &base);
        if (nbytes > 0)
        {
          ebuf = buf + nbytes;
          cp = buf;
          while (cp < ebuf)
          {
            dp = (struct dirent *)cp;
            if (lwip_isdigit(dp->d_name[0]))
            {
              unsigned char idx = dp->d_name[0] - '0';

              sensors[idx].num = idx+1;
              strncpy(&sensors[idx].file[0], dp->d_name, SENSOR_NAME_LEN);
              printf("%s\n", sensors[idx].file);
            }
            cp += dp->d_reclen;
          }
        }
      }
      while (nbytes > 0);

      free(buf);
    }
    close(fd);
  }
#else /* SENSORS_USE_FILES && SENSORS_SEARCH_FILES */
  for (i = 0; i < SENSOR_COUNT; i++) {
    sensors[i].num = (u8_t)(i + 1);
    snprintf(sensors[i].file, sizeof(sensors[i].file), "%d.txt", i);

#if !SENSORS_USE_FILES
    /* initialize sensor value to != zero */
    sensors[i].value = 11 * (i+1);
#endif /* !SENSORS_USE_FILES */
  }
#endif /* SENSORS_USE_FILE && SENSORS_SEARCH_FILES */
}

/* sensorcount .1.3.6.1.4.1.26381.1.2 */
static s16_t
sensor_count_get_value(struct snmp_node_instance* instance, void* value)
{
  size_t count = 0;
  u32_t *uint_ptr = (u32_t*)value;

  LWIP_UNUSED_ARG(instance);

  for(count=0; count<LWIP_ARRAYSIZE(sensors); count++) {
    if(sensors[count].num == 0) {
      *uint_ptr = (u32_t)count;
      return sizeof(*uint_ptr);
    }
  }

  return 0;
}

/* sensortable .1.3.6.1.4.1.26381.1.1 */
/* list of allowed value ranges for incoming OID */
static const struct snmp_oid_range sensor_table_oid_ranges[] = {
  { 1, SENSOR_MAX+1 }
};

static snmp_err_t
sensor_table_get_cell_instance(const u32_t* column, const u32_t* row_oid, u8_t row_oid_len, struct snmp_node_instance* cell_instance)
{
  u32_t sensor_num;
  size_t i;

  LWIP_UNUSED_ARG(column);

  /* check if incoming OID length and if values are in plausible range */
  if(!snmp_oid_in_range(row_oid, row_oid_len, sensor_table_oid_ranges, LWIP_ARRAYSIZE(sensor_table_oid_ranges))) {
    return SNMP_ERR_NOSUCHINSTANCE;
  }

  /* get sensor index from incoming OID */
  sensor_num = row_oid[0];

  /* find sensor with index */
  for(i=0; i<LWIP_ARRAYSIZE(sensors); i++) {
    if(sensors[i].num != 0) {
      if(sensors[i].num == sensor_num) {
        /* store sensor index for subsequent operations (get/test/set) */
        cell_instance->reference.u32 = (u32_t)i;
        return SNMP_ERR_NOERROR;
      }
    }
  }

  /* not found */
  return SNMP_ERR_NOSUCHINSTANCE;
}

static snmp_err_t
sensor_table_get_next_cell_instance(const u32_t* column, struct snmp_obj_id* row_oid, struct snmp_node_instance* cell_instance)
{
  size_t i;
  struct snmp_next_oid_state state;
  u32_t result_temp[LWIP_ARRAYSIZE(sensor_table_oid_ranges)];

  LWIP_UNUSED_ARG(column);

  /* init struct to search next oid */
  snmp_next_oid_init(&state, row_oid->id, row_oid->len, result_temp, LWIP_ARRAYSIZE(sensor_table_oid_ranges));

  /* iterate over all possible OIDs to find the next one */
  for(i=0; i<LWIP_ARRAYSIZE(sensors); i++) {
    if(sensors[i].num != 0) {
      u32_t test_oid[LWIP_ARRAYSIZE(sensor_table_oid_ranges)];

      test_oid[0] = sensors[i].num;

      /* check generated OID: is it a candidate for the next one? */
      snmp_next_oid_check(&state, test_oid, LWIP_ARRAYSIZE(sensor_table_oid_ranges), (void*)i);
    }
  }

  /* did we find a next one? */
  if(state.status == SNMP_NEXT_OID_STATUS_SUCCESS) {
    snmp_oid_assign(row_oid, state.next_oid, state.next_oid_len);
    /* store sensor index for subsequent operations (get/test/set) */
    cell_instance->reference.u32 = LWIP_CONST_CAST(u32_t, state.reference);
    return SNMP_ERR_NOERROR;
  }

  /* not found */
  return SNMP_ERR_NOSUCHINSTANCE;
}

static s16_t
sensor_table_get_value(struct snmp_node_instance* instance, void* value)
{
  u32_t i = instance->reference.u32;
  s32_t *temperature = (s32_t *)value;

  switch (SNMP_TABLE_GET_COLUMN_FROM_OID(instance->instance_oid.id))
  {
  case 1: /* sensor value */
#if SENSORS_USE_FILES
    FILE* sensf;
    char senspath[sizeof(SENSORS_DIR)+1+SENSOR_NAME_LEN+1] = SENSORS_DIR"/";

    strncpy(&senspath[sizeof(SENSORS_DIR)],
            sensors[i].file,
            SENSOR_NAME_LEN);
    sensf = fopen(senspath,"r");
    if (sensf != NULL)
    {
      fscanf(sensf,"%"S32_F,temperature);
      fclose(sensf);
    }
#else /* SENSORS_USE_FILES */
    *temperature = sensors[i].value;
#endif /* SENSORS_USE_FILES */
    return sizeof(s32_t);
  case 2: /* file name */
    MEMCPY(value, sensors[i].file, strlen(sensors[i].file));
    return (s16_t)strlen(sensors[i].file);
  default:
    return 0;
  }
}

static snmp_err_t
sensor_table_set_value(struct snmp_node_instance* instance, u16_t len, void *value)
{
  u32_t i = instance->reference.u32;
  s32_t *temperature = (s32_t *)value;
#if SENSORS_USE_FILES
  FILE* sensf;
  char senspath[sizeof(SENSORS_DIR)+1+SENSOR_NAME_LEN+1] = SENSORS_DIR"/";

  strncpy(&senspath[sizeof(SENSORS_DIR)],
          sensors[i].file,
          SENSOR_NAME_LEN);
  sensf = fopen(senspath, "w");
  if (sensf != NULL)
  {
    fprintf(sensf, "%"S32_F, *temperature);
    fclose(sensf);
  }
#else /* SENSORS_USE_FILES */
  sensors[i].value = *temperature;
#endif /* SENSORS_USE_FILES */

  LWIP_UNUSED_ARG(len);

  return SNMP_ERR_NOERROR;
}

#endif /* LWIP_SNMP */