c++ - 如何在 net-snmp 中打印整数和 Counter32 值

Question

我创建了这段打印字符串值的代码，它运行良好:

 add_mibdir("."); 
 pdu = snmp_pdu_create(SNMP_MSG_GET);

 read_objid(if_index, id_oid, &id_len);
 snmp_add_null_var(pdu, id_oid, id_len);    
 status = snmp_synch_response(sess_handle,pdu,&response);

 int count=1;
 for(vars = response->variables; vars; vars = vars->next_variable) 
  {
    if (vars->type == ASN_OCTET_STR) 
    {
        char *sp = (char *)malloc(1 + vars->val_len);
        memcpy(sp, vars->val.string, vars->val_len);
        sp[vars->val_len] = '\0';
        printf("value #%d is a string: %s\n", count++, sp);
        printf("%s\n",vars->val.string);
        free(sp);
}

  }

示例:对于 SNMPv2-SMI::mib-2.47.1.1.1.1.2.1012 = STRING: "GigabitEthernet Container"，它返回 "GigabitEthernet Container";

但我尝试了一个整数值，但没有成功:

for(vars = response->variables; vars; vars = vars->next_variable)
    printf("%ld",(long int)vars->val.integer);//it returns large numbers;

示例:对于 SNMPv2-SMI::mib-2.17.2.11.0 = INTEGER: 1500，我想返回 1500，对于 IF-MIB::ifOutBroadcastPkts.10103 = Counter32: 14011112 我想返回 14011112

如果我使用:

for(vars = response->variables; vars; vars = vars->next_variable)
    print_variable(vars->name, vars->name_length, vars);

它返回Counter32:12132，或INTEGER:12324，或STRING:Gi0/1(但我想解析这个结果并将它用到一些没有数据类型的变量中，例如:在 var a 中存储 12132)。

谢谢!

Answer 1

如果有人仍然对此有疑问，我想出了一个不需要使用 net-snmp 5.7.3 进行解析的替代机制:

template<typename T>
static boost::shared_ptr< std::vector<T> > GetVector(std::string user_oid, struct snmp_session * snmp_session) {

    // Other Initialization ....

    char temp_buf[BUFSIZ];
    size_t temp_buf_len = BUFSIZ;
    bool orig_config_val_qp = netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICK_PRINT);
    bool orig_config_val_bv = netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_PRINT_BARE_VALUE);

    // Enforce this for correct output in snprint_variable functions
    netsnmp_ds_set_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICK_PRINT, 1);
    netsnmp_ds_set_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_PRINT_BARE_VALUE, 1);

    // oid conversion routines ...

    // Processing loop for response vars (similar to netsnmp/app/snmpbulkwalk.c) ...
    if (vars->type == ASN_OCTET_STR) 
    {
        temp_buf_len = BUFSIZ;
        snprint_variable(temp_buf, temp_buf_len, vars->name, vars->name_length, vars);
        result->push_back(boost::lexical_cast<T>(temp_buf));
    }
    // End Processing loop...

    // Restore configuration
    netsnmp_ds_set_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICK_PRINT, orig_config_val_qp);
    netsnmp_ds_set_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_PRINT_BARE_VALUE, orig_config_val_bv);

    return result;
} 

这将使您的应用程序配置的其余部分保持原样，并且只吐出值，因此您不需要标记化。我缩短了循环，以便它专注于重要方面。