/**
 * \file mibquery.c
 *
 *  Extracts requested data from MIB II.
 *
 *  Makes query for specified data to MIB II using SNMP protocol.
 *
 * \author Tomas Jirak, Vladimir Sochor
 * \date 2003 
 */

#include "snmp.h"
#include "snmp_impl.h"
#include "snmp_client.h"
#include "mib.h"
#include "mibquery.h"

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

extern int val_count;
extern char *tab_values[];
extern struct snmp_session *p_session;

/**
 * Prints error message on the standard output.
 */
void error_msg(int errCode, char *errMsg)
{
  printf("ERROR: %s\n", errMsg);
  printf("error code %d: %s\n", errCode, strerror(errCode));
  return;
}

/**
 * Odesle dotaz SNMP agentovi bezicim na stroji 'host' na obsah objektu 'mibTable'.
 * Pri uspechu ulozi ziskana data do pole 'tab_values' a vrati 1, jinak vrati 0.
 */
int mib_query(char *host, char *mibTable)    
{
  struct snmp_pdu *pdu, *response;
  struct variable_list *vars;
  char obj_out[MAX_OID_LEN];
  char val_out[BUF_SIZE];
  char buff[BUF_SIZE];
  oid name[MAX_NAME_LEN]; 
  int name_len; 
  oid root[MAX_NAME_LEN];
  int root_len;
  int i;
  int status, ret;
  int continue_flag = 1;  

  root_len = MAX_NAME_LEN;
  if (!read_objid(mibTable, &root[0], &root_len))
    error_msg(errno, "Invalid object identifier");
  
  name_len = root_len;
  bcopy((char *) &root[0], (char *) &name[0], root_len*sizeof(oid));

  while (continue_flag) {

    pdu = snmp_pdu_create(GETNEXT_REQ_MSG);
    snmp_add_null_var(pdu, name, name_len);
    status = snmp_synch_response(p_session, pdu, &response);
 
    ret = 1; 
    switch (status) {
  /* status == STAT_SUCCESS */  
    case STAT_SUCCESS:   
      if (response->errstat == SNMP_ERR_NOERROR) {
        if (response->command == REPORT_MSG) {
          printf("Operation wasn't succesfull -- error report.\n");
          for (vars = response->variables; vars; vars = vars->next_variable) {
            sprint_objid(obj_out, vars->name, vars->name_length);
            sprint_variable(val_out, vars->name, vars->name_length, vars);
          }
        }

      vars = response->variables;
      if (vars->name_length < root_len || bcmp(&root[0], vars->name, root_len*sizeof(oid))) {
        continue_flag = 0;
        break;
      }
  
      if (vars->type != SNMP_ENDOFMIBVIEW) {
        if (response->command == REPORT_MSG)
          printf("This is an error report\n");
  
        sprint_objid(obj_out, vars->name, vars->name_length);
        sprint_variable(buff, vars->name, vars->name_length, vars);
        strcpy(val_out, (char *) &buff[strlen(obj_out)]);
        for (i = 0; i < strlen(val_out); i++)
          if (val_out[i] == '\n')
	    val_out[i] = '\0';
        tab_values[val_count] = (char *) malloc(BUF_SIZE);
        strcpy(tab_values[val_count], val_out);
        val_count++;
        bcopy((char *) vars->name, (char *) &name[0], (vars->name_length)*sizeof(oid));
        name_len = vars->name_length;
      }
    } 
    else { /* response->errstat != SNMP_ERR_NOERROR */
      continue_flag = 0;  
      if (response->errstat == SNMP_ERR_NOSUCHNAME) {
        strcpy(obj_out, "End of MIB.");
        ret = 0;
      }
      else {
        strcpy(obj_out, "Error in packet.");
        if (response->errstat == SNMP_ERR_NOSUCHNAME) {	  
          strcpy(val_out, "The request for object identifier failed.");
          ret = 0;	 
        }
      }
    }
    break;
    /* status == STAT_TIMEOUT */  
    case STAT_TIMEOUT:
      error_msg(errno, "No response from host.");
      continue_flag = 0;
      ret = 0;
      break;
    /* status == STAT_ERROR */
    case STAT_ERROR:
      error_msg(errno, "An unknown error occurred.");
      continue_flag = 0; 
      ret = 0;
      break;
    default:
      continue_flag = 0;
      break;
    }
  } //while  
    		
  if (response)
    snmp_free_pdu(response);

  return(ret); 
}

/**
 * Prints results - data from 'at' table - on standard output.
 */
void print_table(int count)
{
  int i;
  int i_max = count/3;
  int i_max2 = 2*i_max;

  printf("------------------------------------------------------------------\n");
  printf(" atIfIndex  |  atPhysAddress  |  atNetAddress\n");
  printf("------------------------------------------------------------------\n\n");
  for (i = 0; i < i_max; i++) 
  printf(" %s  |  %s  |  %s\n", tab_values[i], tab_values[i+i_max], tab_values[i+i_max2]);
  printf("------------------------------------------------------------------\n\n");
  printf("Totally %d rows.\n\n", i_max);
}