/*
 *  Semestralni prace z predmetu PSI - vypis SNMP tabulky at
 *  Vypis polozek:  atPhysAddress, atNetAddress
 *  Petr Chudes, Ondrej Patka, 2002
 */

#include "snmp_api.h"
#include "snmp_client.h"
#include "snmp.h"


oid tabulka[256] = {1, 3, 6, 1, 2, 1, 3, 1, 1, 2};
oid delka_tab = 10;
char *community,*hostname;
int konec_vypisu;

void vypis_hlavicku(void) {
  printf("\nSemestralni prace z predmetu PSI"
         "\nPetr Chudes, Ondrej Patka, 2002"
	 "\nVypis casti SNMP tabulky AT (1.3.6.1.2.1.3.1.1)"
	 "\n  vypisovane polozky:   atIfIndex     (.1)"
	 "\n                        atPhysAddress (.2)"
	 "\n                        atNetAddress  (.3)"
	 "\n---------------------------------------------------------\n");
}

int zpracovani(int operation, struct snmp_session* session, int reqid, struct snmp_pdu *pdu, void *magic)
{
 int i;
 for (i=0;i<10;i++)
   if (tabulka[i] != *(pdu->variables->name+i)) konec_vypisu = 1;
 if (konec_vypisu == 1) 
   return 0;
 switch (tabulka[9]){
   case 1: /*ifIndex*/
           printf("   |   %2d\n",*(pdu->variables->val.integer));
           break; 
   case 2 : /*atPhysAddress*/
           memcpy(tabulka, pdu->variables->name,pdu->variables->name_length*sizeof(oid));
           delka_tab = pdu->variables->name_length;
//           printf("%3d.%3d.%3d.%3d.%3d.%3d - ", tabulka[10], tabulka[11], tabulka[12]
//                                              , tabulka[13], tabulka[14], tabulka[15]);
           printf(" ");
           for (i=0;i<pdu->variables->val_len;i++){
             printf("%02x ",*(pdu->variables->val.string+i));
           }
           printf(" |  ");
           break;
   case 3 : /*atNetAddress*/
           for (i=0;i<pdu->variables->val_len-1;i++){
             printf("%3d.",*(pdu->variables->val.string+i));
           }
           printf("%3d",*(pdu->variables->val.string+i));
           break; 
  }
 return 0;
}

/******************************************************************
* Funkce pro nacteni dat z AT tabulky a jejich vypis na obrazovku *
******************************************************************/
int vypis_at_table(void) {
  int cislo_spojeni;
  struct snmp_session *nove_spojeni, *otevrene_spojeni;
  struct snmp_pdu *pdu;
  int numfds;
  fd_set fdset;
  struct timeval to;
  int block;

  /* vytvoreni noveho spojeni - naplneni struktury snmp_session */ 
  nove_spojeni = (struct snmp_session *) calloc (1, sizeof (struct snmp_session));
  nove_spojeni->retries = SNMP_API_DEFAULT_RETRIES;  /* Number of retries befor timeout */
  nove_spojeni->timeout = SNMP_API_DEFAULT_TIMEOUT;  /* Number of uS until first timeout, then exponencial backoff */
  nove_spojeni->peername = hostname;	             /* Domain name or dotted IP address or default peer */		
  nove_spojeni->remote_port = SNMP_PORT;             /* UDP port number of peer */		
  nove_spojeni->local_port = 0;                      /* My UDP port number, 0 for default, picked for randomly */
  nove_spojeni->authenticator = NULL;	             /* Authentification function or NULL */ 		
  nove_spojeni->callback = (int (*)())zpracovani;    /* Function to interpret incoming data */
  nove_spojeni->version = SNMP_VERSION_1;            /* SNMP version number */
  nove_spojeni->community_len = 0;		     /* community */
  nove_spojeni->community = community;

  /* otevreni noveho spojeni */
  if ((otevrene_spojeni = snmp_open(nove_spojeni)) == NULL) 
    return 255;
  cislo_spojeni = snmp_select_info(&numfds, &fdset, &to, &block);

  printf(" atPhysAddress(.2)  |  atNetAddress(.3)  |  atIfIndex(.1)\n"
         "---------------------------------------------------------\n");  
  /* nacitani a vypis az do konce tabulky */
  konec_vypisu = 0;
  while (konec_vypisu == 0) {
    /* vytvoreni pdu s prikazem GETNEXT */    
    pdu = snmp_pdu_create(GETNEXT_REQ_MSG);
    /* pridani nulove polozky na konec parametru */
    snmp_add_null_var(pdu, tabulka, delka_tab);
    /* ASN type of variable */
    pdu->variables->type = 6;  
    /* poslani UDP paketu s pdu */
    if ((snmp_send(otevrene_spojeni, pdu)) == 0) 
      return -1;
    /* cteni odpovedi */
    snmp_read(&fdset);
    /* uvolneni pameti pdu */
    snmp_free_pdu(pdu);
   
    /* posilani prikazu GET */
    pdu = snmp_pdu_create(GET_REQ_MSG);
    tabulka[9] = 3;
    snmp_add_null_var(pdu, tabulka, delka_tab);
    pdu->variables->type = 6;
    if ((snmp_send(otevrene_spojeni, pdu)) == 0) 
      return -1;
    snmp_read(&fdset);
    snmp_free_pdu(pdu);
    tabulka[9] = 1;

    /* posilani prikazu GET */
    pdu = snmp_pdu_create(GET_REQ_MSG);
    snmp_add_null_var(pdu, tabulka, delka_tab);
    pdu->variables->type = 6;
    if ((snmp_send(otevrene_spojeni, pdu)) == 0) 
      return 255;
    snmp_read(&fdset);
    snmp_free_pdu(pdu);
    tabulka[9] = 2;
  }
  if ((snmp_close(nove_spojeni)) == 0) 
    return 255;
  free((void *)nove_spojeni);
  free((void *)otevrene_spojeni);
} 


/* hlavni funkce programu */
int main(int argc,char *argv[])
{
  switch (argc) {
    case 1:
      // nebyly zadany parametry host a community
      hostname = (char *) malloc(9+1, sizeof(char));
      strcpy(hostname, "localhost");
      community = (char *) malloc(6+1, sizeof(char));
      strcpy(community, "public");
    break;
    case 2:
      // zadan pouze host name -> community automaticky public
      hostname = (char *) malloc(strlen(argv[1])+1, sizeof(char));
      strcpy(hostname, argv[1]);
      community = (char *) malloc(6+1, sizeof(char));
      strcpy(community, "public");
    break;
    case 3:
      // zadan host i community
      hostname = (char *) malloc(strlen(argv[1])+1, sizeof(char));
      strcpy(hostname, argv[1]);
      community = (char *) malloc(strlen(argv[2])+1, sizeof(char));
      strcpy(community, argv[2]);
    break;
    default:
      printf("\nProgram nebyl spravne spusten!\n");
      printf("\nSpravne spusteni:  vypis_at <hostname> <community>\n");
      return(0);
    break;
  }
  vypis_hlavicku();
  vypis_at_table();
  return 0;
}