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@poruruba

ESP32をSNMPエージェントにする

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Last updated at Posted at 2026-01-12

ESP32の稼働状態を外部から把握できるように、SNMPエージェントにします。

以下のライブラリを使わせていただきました。

0neblock/SNMP_Agent

ソース

こんな感じ

lib_snmp.cpp
#include <Arduino.h>
#include "main_config.h"

#ifdef _SNMP_AGENT_ENABLE_

#include <WiFi.h>
#include <WiFiUdp.h>
#include <SPIFFS.h>
#include <SNMP_Agent.h>
#include "wifi_utils.h"
#include "storage_info.h"

#include "quickjs_esp32.h"

#define IDEAL_LOOP_PERIOD 8000

static WiFiUDP udp;
static SNMPAgent snmp("public");

extern ESP32QuickJS qjs;

#define hrStorageOther        ".1.3.6.1.2.1.25.2.1.1"
#define hrStorageRam          ".1.3.6.1.2.1.25.2.1.2"
#define hrStorageVirtualMemory ".1.3.6.1.2.1.25.2.1.3"
#define hrStorageFixedDisk    ".1.3.6.1.2.1.25.2.1.4"
#define hrStorageFlashMemory  ".1.3.6.1.2.1.25.2.1.9"

static uint32_t lastLoopMicros = 0;
static int cpuLoadRaw = 0;

// 多重平均
static float avgFast = 0;
static float avgMid  = 0;
static float avgSlow = 0;

long snmp_initialize(void)
{
  if( !wifi_is_connected() )
    return -1;

  snmp.setUDP(&udp);
  snmp.begin();

  // system.sysDescr
  snmp.addReadOnlyStaticStringHandler(
    ".1.3.6.1.2.1.1.1.0",
    std::string("ESP32 SNMP Agent")
  );
  // system.sysObjectID
  snmp.addOIDHandler(
    ".1.3.6.1.2.1.1.2.0",
    ".1.3.6.1.4.1.8072.3.2.255"
  );
  // system.sysUpTime
  snmp.addDynamicReadOnlyTimestampHandler(
    ".1.3.6.1.2.1.1.3.0",
    []() -> uint32_t {
        return millis() / 10;
    }
  );
  // system.sysName
  snmp.addReadOnlyStaticStringHandler(
    ".1.3.6.1.2.1.1.5.0",
    std::string(MDNS_NAME)
  );
  // system.sysServices
  snmp.addReadOnlyIntegerHandler(
    ".1.3.6.1.2.1.1.7.0",
    72
  );
  // interface.ifNumber
  snmp.addReadOnlyIntegerHandler(
    ".1.3.6.1.2.1.2.1.0",
    1
  );
  // interface.ifIndex
  snmp.addReadOnlyIntegerHandler(
    ".1.3.6.1.2.1.2.2.1.1.1",
    1
  );
  // interface.ifDescr
  snmp.addReadOnlyStaticStringHandler(
    ".1.3.6.1.2.1.2.2.1.2.1",
    std::string("wifi")
  );
  // interface.ifType
  snmp.addReadOnlyIntegerHandler(
    ".1.3.6.1.2.1.2.2.1.3.1",
    71
  );
  // interface.ifMtu
  snmp.addReadOnlyIntegerHandler(
    ".1.3.6.1.2.1.2.2.1.4.1",
    1500
  );
  uint8_t mac[6];
  WiFi.macAddress(mac);
  // interface.ifPhysAddress
  snmp.addReadOnlyStaticStringHandler(
    ".1.3.6.1.2.1.2.2.1.6.1",
    std::string((char*)mac, sizeof(mac))
  );
  // interface.ifAdminStatus
  snmp.addReadOnlyIntegerHandler(
    ".1.3.6.1.2.1.2.2.1.7.1",
    1
  );
  // interface.ifOperStatus
  snmp.addDynamicIntegerHandler(
    ".1.3.6.1.2.1.2.2.1.8.1",
    []() -> int {
        return (WiFi.status() == WL_CONNECTED) ? 1 : 2; 
    }
  );

  // 1:flash, 2:spiffs, 3:ram, 4:heap, 5:psram, 6:stack
  // hrStorageType
  snmp.addOIDHandler(".1.3.6.1.2.1.25.2.3.1.2.1", hrStorageFlashMemory);
  snmp.addOIDHandler(".1.3.6.1.2.1.25.2.3.1.2.2", hrStorageFixedDisk);
  snmp.addOIDHandler(".1.3.6.1.2.1.25.2.3.1.2.3", hrStorageRam);
  snmp.addOIDHandler(".1.3.6.1.2.1.25.2.3.1.2.4", hrStorageRam);
  snmp.addOIDHandler(".1.3.6.1.2.1.25.2.3.1.2.5", hrStorageRam);
  snmp.addOIDHandler(".1.3.6.1.2.1.25.2.3.1.2.6", hrStorageRam);

  // hrStorageDescr
  snmp.addReadOnlyStaticStringHandler (".1.3.6.1.2.1.25.2.3.1.3.1", std::string("flash"));
  snmp.addReadOnlyStaticStringHandler (".1.3.6.1.2.1.25.2.3.1.3.2", std::string("spiffs"));
  snmp.addReadOnlyStaticStringHandler (".1.3.6.1.2.1.25.2.3.1.3.3", std::string("ram"));
  snmp.addReadOnlyStaticStringHandler (".1.3.6.1.2.1.25.2.3.1.3.4", std::string("heap"));
  snmp.addReadOnlyStaticStringHandler (".1.3.6.1.2.1.25.2.3.1.3.5", std::string("psram"));
  snmp.addReadOnlyStaticStringHandler (".1.3.6.1.2.1.25.2.3.1.3.6", std::string("stack"));

  // hrStorageAllocationUnits
  snmp.addReadOnlyIntegerHandler (".1.3.6.1.2.1.25.2.3.1.4.1", 1);
  snmp.addReadOnlyIntegerHandler (".1.3.6.1.2.1.25.2.3.1.4.2", 1);
  snmp.addReadOnlyIntegerHandler (".1.3.6.1.2.1.25.2.3.1.4.3", 1);
  snmp.addReadOnlyIntegerHandler (".1.3.6.1.2.1.25.2.3.1.4.4", 1);
  snmp.addReadOnlyIntegerHandler (".1.3.6.1.2.1.25.2.3.1.4.5", 1);
  snmp.addReadOnlyIntegerHandler (".1.3.6.1.2.1.25.2.3.1.4.6", 1);
  
  // hrStorageSize
  snmp.addReadOnlyIntegerHandler(".1.3.6.1.2.1.25.2.3.1.5.1", getFlashSize());
  snmp.addReadOnlyIntegerHandler(".1.3.6.1.2.1.25.2.3.1.5.2", SPIFFS.totalBytes());
  snmp.addDynamicIntegerHandler(".1.3.6.1.2.1.25.2.3.1.5.3",
    []() -> int {
      return getRamTotal();
    }
  );
  snmp.addDynamicIntegerHandler(".1.3.6.1.2.1.25.2.3.1.5.4",
    []() -> int {
      return ESP.getHeapSize();
    }
  );
  snmp.addReadOnlyIntegerHandler(".1.3.6.1.2.1.25.2.3.1.5.5", ESP.getPsramSize());
  snmp.addDynamicIntegerHandler(".1.3.6.1.2.1.25.2.3.1.5.6", 
    []() -> int {
      JSMemoryUsage usage;
      qjs.getMemoryUsage(&usage);
      return usage.malloc_limit;
    }
  );

  // hrStorageUsed
  snmp.addReadOnlyIntegerHandler(".1.3.6.1.2.1.25.2.3.1.6.1", getPartitionApplication());
  snmp.addDynamicIntegerHandler(".1.3.6.1.2.1.25.2.3.1.6.2", 
    []() -> int {
      return SPIFFS.usedBytes();
    }
  );
  snmp.addDynamicIntegerHandler(".1.3.6.1.2.1.25.2.3.1.6.3",
    []() -> int {
      return getRamUsed();
    }
  );
  snmp.addDynamicIntegerHandler(".1.3.6.1.2.1.25.2.3.1.6.4",
    []() -> int {
      return ESP.getFreeHeap();
    }
  );
  snmp.addDynamicIntegerHandler(".1.3.6.1.2.1.25.2.3.1.6.5",
    []() -> int {
      return ESP.getFreePsram();
    }
  );
  snmp.addDynamicIntegerHandler(".1.3.6.1.2.1.25.2.3.1.6.6",
    []() -> int {
      JSMemoryUsage usage;
      qjs.getMemoryUsage(&usage);
      return usage.malloc_size;
    }
  );

  // hrProcessorLoad
  snmp.addDynamicIntegerHandler(
    ".1.3.6.1.2.1.25.3.3.1.2.1",
    []() -> int {
      return (int)(avgSlow + 0.5);
    }
  );

  lastLoopMicros = micros();

  return 0;
}

static void snmp_perform(void) {
  uint32_t now = micros();
  uint32_t diff = now - lastLoopMicros;
  lastLoopMicros = now;

  const uint32_t ideal = IDEAL_LOOP_PERIOD;
  if (diff <= ideal) {
    cpuLoadRaw = 0;
  } else {
    uint32_t over = diff - ideal;
    cpuLoadRaw = over * 100 / ideal;
    if (cpuLoadRaw > 100) cpuLoadRaw = 100;
  }

  avgFast = avgFast * 0.7 + cpuLoadRaw * 0.3;
  avgMid  = avgMid  * 0.85 + avgFast * 0.15;
  avgSlow = avgSlow * 0.95 + avgMid  * 0.05;
}

long snmp_loop(void)
{
  snmp_perform();
  snmp.loop();

  return 0;
}

#endif

ストレージ情報

storage_info.cpp
#include "esp_ota_ops.h"
#include "esp_partition.h"
#include "esp_heap_caps.h"

unsigned long getRamUsed(void) {
  multi_heap_info_t info;
  heap_caps_get_info(&info, MALLOC_CAP_DEFAULT);

  unsigned long used  = info.total_allocated_bytes;
  return used;
}

unsigned long getRamTotal(void) {
  multi_heap_info_t info;
  heap_caps_get_info(&info, MALLOC_CAP_DEFAULT);

  unsigned long total = info.total_free_bytes + info.total_allocated_bytes;
  return total;
}

unsigned long getPartitionApplication(void) {
  const esp_partition_t* running = esp_ota_get_running_partition();
  return running->size;
}

unsigned long getFlashSize(void) {
  uint32_t flash_size = 0;
  esp_flash_get_size(NULL, &flash_size);
  return flash_size;
}

返している情報

MIB OID 内容
system.sysDescr .1.3.6.1.2.1.1.1.0 ”ESP32 SNMP Agent”
system.sysObjectID .1.3.6.1.2.1.1.2.0 unknown
system.sysUpTime .1.3.6.1.2.1.1.3.0 起動してからの時間
system.sysName .1.3.6.1.2.1.1.5.0 MDNS_NAME
system.sysServices .1.3.6.1.2.1.1.7.0 72
interface.ifNumber .1.3.6.1.2.1.2.1.0 1
interface.ifIndex .1.3.6.1.2.1.2.2.1.1.1 1
interface.ifDescr .1.3.6.1.2.1.2.2.1.2.1 "wifi"
interface.ifType .1.3.6.1.2.1.2.2.1.3.1 71
interface.ifMtu .1.3.6.1.2.1.2.2.1.4.1 1500
interface.ifPhysAddress .1.3.6.1.2.1.2.2.1.6.1 MAC アドレス
interface.ifAdminStatus .1.3.6.1.2.1.2.2.1.7.1 1
interface.ifOperStatus .1.3.6.1.2.1.2.2.1.8.1 WiFi 接続状態
hrProcessorLoad .1.3.6.1.2.1.25.3.3.1.2.1 CPU 負荷
hrStorageIndex hrStorageType hrStorageDescr ストレージ種別
1 hrStorageFlashMemory "flash" フラッシュ
2 hrStorageFixedDisk "spiffs" SPIFFS
3 hrStorageRam "ram" RAM
4 hrStorageRam "heap" ヒープ
5 hrStorageRam "psram" PSRAM
6 hrStorageRam "stack" スタック(Javascript)
MIB OID(X=1～6) 内容
hrStorageType .1.3.6.1.2.1.25.2.3.1.2.X ストレージタイプ
hrStorageDescr .1.3.6.1.2.1.25.2.3.1.3.X ストレージ名
hrStorageSize .1.3.6.1.2.1.25.2.3.1.5.X 全体ストレージサイズ
hrStorageUsed .1.3.6.1.2.1.25.2.3.1.6.X 使用済みストレージサイズ

M5Stack Fire での実行例

$ snmpwalk -v1 192.168.1.XXX -c public 
SNMPv2-MIB::sysDescr.0 = STRING: ESP32 SNMP Agent 
SNMPv2-MIB::sysObjectID.0 = OID: NET-SNMP-TC::unknown 
DISMAN-EXPRESSION-MIB::sysUpTimeInstance = Timeticks: (10582) 0:01:45.82 
SNMPv2-MIB::sysName.0 = STRING: QuickJS_ESP32_M5Stack 
SNMPv2-MIB::sysServices.0 = INTEGER: 72 
IF-MIB::ifNumber.0 = INTEGER: 1 
IF-MIB::ifIndex.1 = INTEGER: 1 
IF-MIB::ifDescr.1 = STRING: wifi 
IF-MIB::ifType.1 = INTEGER: ieee80211(71) 
IF-MIB::ifMtu.1 = INTEGER: 1500 
IF-MIB::ifPhysAddress.1 = STRING: XX:XX:XX:XX:XX:XX 
IF-MIB::ifAdminStatus.1 = INTEGER: up(1) 
IF-MIB::ifOperStatus.1 = INTEGER: up(1) 
HOST-RESOURCES-MIB::hrStorageType.1  =  OID:  HOST-RESOURCES-TYPES::hrStorageFlashMemory 
HOST-RESOURCES-MIB::hrStorageType.2  =  OID:  HOST-RESOURCES-TYPES::hrStorageFixedDisk 
HOST-RESOURCES-MIB::hrStorageType.3  =  OID:  HOST-RESOURCES-TYPES::hrStorageRam 
HOST-RESOURCES-MIB::hrStorageType.4  =  OID:  HOST-RESOURCES-TYPES::hrStorageRam 
HOST-RESOURCES-MIB::hrStorageType.5  =  OID:  HOST-RESOURCES-TYPES::hrStorageRam 
HOST-RESOURCES-MIB::hrStorageType.6  =  OID:  HOST-RESOURCES-TYPES::hrStorageRam 
HOST-RESOURCES-MIB::hrStorageDescr.1 = STRING: flash 
HOST-RESOURCES-MIB::hrStorageDescr.2 = STRING: spiffs 
HOST-RESOURCES-MIB::hrStorageDescr.3 = STRING: ram 
HOST-RESOURCES-MIB::hrStorageDescr.4 = STRING: heap 
HOST-RESOURCES-MIB::hrStorageDescr.5 = STRING: psram 
HOST-RESOURCES-MIB::hrStorageDescr.6 = STRING: stack 
HOST-RESOURCES-MIB::hrStorageSize.1 = INTEGER: 16777216 
HOST-RESOURCES-MIB::hrStorageSize.2 = INTEGER: 836081 
HOST-RESOURCES-MIB::hrStorageSize.3 = INTEGER: 4445963 
HOST-RESOURCES-MIB::hrStorageSize.4 = INTEGER: 281840 
HOST-RESOURCES-MIB::hrStorageSize.5 = INTEGER: 4192123 
HOST-RESOURCES-MIB::hrStorageSize.6 = INTEGER: 50352 
HOST-RESOURCES-MIB::hrStorageUsed.1 = INTEGER: 3145728 
HOST-RESOURCES-MIB::hrStorageUsed.2 = INTEGER: 4267 
HOST-RESOURCES-MIB::hrStorageUsed.3 = INTEGER: 199004 
HOST-RESOURCES-MIB::hrStorageUsed.4 = INTEGER: 66508 
HOST-RESOURCES-MIB::hrStorageUsed.5 = INTEGER: 4187843 
HOST-RESOURCES-MIB::hrStorageUsed.6 = INTEGER: 9456 
HOST-RESOURCES-MIB::hrProcessorLoad.1 = INTEGER: 0 
HOST-RESOURCES-MIB::hrProcessorLoad.1 = No more variables left in this MIB View (It is past the end of the MIB tree)

(参考) ESP32で動作するJavascript実行環境

ESP32で動作するJavascript実行環境を公開しています。
この中で実装しています。

「電子書籍：M5StackとJavascriptではじめるIoTデバイス制御」

サポートサイト

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