SNMP v2c and v3 Support in STM32H753ZI with LwIP

Hello,

I am working on an SNMP implementation using STM32H753ZI with the LwIP Ethernet stack.

Currently, SNMP v1 is working successfully, including trap generation and reception testing using Net-SNMP tools. I am able to send enterprise-specific traps from the STM32 device.

Below is the trap code currently working for SNMP v1:

void send_temp_fault_trap(void)
{
 static const u32_t enterprise_oid_arr[] = {1,3,6,1,4,1,50598};
 struct snmp_obj_id enterprise_oid;
 enterprise_oid.len = LWIP_ARRAYSIZE(enterprise_oid_arr);
 memcpy(enterprise_oid.id,enterprise_oid_arr,sizeof(enterprise_oid_arr));

 ip_addr_t dst;
 IP4_ADDR(&dst, 192,168,0,255);
 snmp_trap_dst_ip_set(0, &dst);
 snmp_trap_dst_enable(0, 1);

 static const u32_t msg_oid_arr[] =
 {
 1,3,6,1,4,1,50898,10
 };

 static struct snmp_varbind vb;
 static struct snmp_obj_id msg_oid;
 static char msg[] = "System Working";
 msg_oid.len = LWIP_ARRAYSIZE(msg_oid_arr);
 memcpy(msg_oid.id,msg_oid_arr,sizeof(msg_oid_arr));

 vb.next = NULL;
 vb.oid = msg_oid;
 vb.type = SNMP_ASN1_TYPE_OCTET_STRING;
 vb.value = (void*)msg;
 vb.value_len = strlen(msg); snmp_send_trap(&enterprise_oid,SNMP_GENTRAP_ENTERPRISE_SPECIFIC,MYTRAP_TEMP_FAULT,&vb);
 printf("SNMP Trap Sent\r\n");
}

Now I want to implement:

1. SNMP v2c support
2. SNMP v3 support

I have some questions regarding LwIP SNMP support on STM32:

• Does the current LwIP SNMP agent fully support SNMP v2c and SNMP v3?
• Are SNMPv2 traps/informs supported?
• Is there any example project available for STM32H7 series?
• Does LwIP provide built-in support for:
  • authentication (MD5/SHA)
  • privacy/encryption (DES/AES)
  • user-based security model (USM)
• Are there any limitations in the STM32CubeH7 package regarding SNMP v3?
• Is Net-SNMP interoperability tested with LwIP SNMP v3 implementation?

I would appreciate guidance or reference examples for enabling SNMP v2c/v3 in STM32 + LwIP.

Thank you.