Is It planned to use net-snmp in LibEvent, like this, but without calling :
void fct_listen(evutil_socket_t listener,short event, void *arg)
{
struct event_base *base = (struct event_base *)arg;
printf("\n fct_listen=%d\n",event);
int fds = 0, block = 0;
fd_set fdset;
struct timeval timeout; // timeout for select()
timeout.tv_sec = 0;
timeout.tv_usec = 10000;
FD_ZERO (&fdset);
snmp_select_info (&fds, &fdset, &timeout, &block);
fds = select (fds, &fdset, NULL, NULL, &timeout);
if (fds)
{ snmp_read(&fdset);
}
else
{
snmp_timeout();
printf("snmp_timeout\n");
// stop evenet loop
event_base_loopbreak(base);
}
}
but only
void fct_listen1(evutil_socket_t listener,short event, void *arg)
{
struct event_base *base = (struct event_base *)arg;
printf("\n fct_listen=%d\n",event);
if (event == 2) snmp_read();
else if (event==1)
{
snmp_timeout();
printf("snmp_timeout\n");
event_base_loopbreak(base);
}
}
Because the callback function fct_listen or fct_listen1 are calling when
socket is up (trame detected)
and don't need the use of "fd_set fdset;"
I added all the code sample.c with the two callback function.
Regards
Didier
#include <sys/types.h>
#include <sys/param.h>
#include <unistd.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
#include <iostream>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <net-snmp/net-snmp-config.h>
#if USE_STDLIB_H
#include <stdlib.h>
#endif
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_STRING_H
#include <string.h>
#else
#include <strings.h>
#endif
#include <sys/types.h>
#if HAVE_NETINET_IN_H
# include <netinet/in.h>
#endif
#if TIME_WITH_SYS_TIME
# ifdef WIN32
# include <sys/timeb.h>
# else
# include <sys/time.h>
# endif
# include <time.h>
#else
# if HAVE_SYS_TIME_H
# include <sys/time.h>
# else
# include <time.h>
# endif
#endif
#if HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
#include <stdio.h>
#if HAVE_WINSOCK_H
#include <winsock.h>
#endif
#if HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#if HAVE_NETDB_H
#include <netdb.h>
#endif
#if HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#include <net-snmp/net-snmp-includes.h>
#include <net-snmp/library/asn1.h>
#include <net-snmp/library/snmp_api.h>
#include <net-snmp/library/snmp_enum.h>
#include <net-snmp/library/parse.h>
#include "C:\\cygwin\\usr\\local\\include\\event2\\event.h"
using namespace std;
static struct event_base* Sample_EventBase = NULL;
int
snmp_input(int op,
netsnmp_session * session,
int reqid, netsnmp_pdu *pdu, void *magic)
{
// struct get_req_state *state = (struct get_req_state *)magic;
netsnmp_variable_list *varlist, *vp;
oid anOID[MAX_OID_LEN];
size_t anOID_len = MAX_OID_LEN;
/* Device information variables */
char ip_addr[1024];
char model[1024];
char device[1024];
/* remote IP detection variables */
netsnmp_indexed_addr_pair *responder;
struct sockaddr_in *remote = NULL;
struct MagicolorCap *cap;
int i;
//netsnmp_variable_list_zp8 *vars;
printf(" ****************begin snmp_input ************** op=%d \n ",op);
if (op == NETSNMP_CALLBACK_OP_RECEIVED_MESSAGE) {
varlist = pdu->variables;
responder = (netsnmp_indexed_addr_pair *) pdu->transport_data;
printf("%s: Handling SNMP response \n", __func__);
if (responder == NULL || pdu->transport_data_length != sizeof(netsnmp_indexed_addr_pair )) {
printf("%s: Unable to extract IP address from SNMP response.\n",__func__);
return 0;
}
remote = (struct sockaddr_in *) &(responder->remote_addr);
if (remote == NULL) {
printf("%s: Unable to extract IP address from SNMP response.\n",__func__);
return 0;
}
snprintf(ip_addr, sizeof(ip_addr), "%s", inet_ntoa(remote->sin_addr));
printf("%s: IP Address of responder is %s\n", __func__, ip_addr);
// System Object ID (Unique OID identifying model)
// This determines whether we really have a magicolor device
anOID_len = MAX_OID_LEN;
read_objid("1.3.6.1.2.1.1.2.0", anOID, &anOID_len);
printf("\n anOID_len=%d \n",anOID_len);
vp = find_varbind_in_list (varlist, anOID, anOID_len);
if (vp) {
printf("\n ee\n");
size_t value_len = vp->val_len/sizeof(oid);
if (vp->type != ASN_OBJECT_ID) {
printf("%s: SystemObjectID does not return an OID, device is not a magicolor device\n", __func__);
return 0;
}
snprint_objid (device, sizeof(device), vp->val.objid, value_len);
printf("%s: Device object ID is '%s'\n", __func__, device);
}
// Retrieve sysDescr (i.e. model name)
anOID_len = MAX_OID_LEN;
read_objid("1.3.6.1.2.1.1.1.0", anOID, &anOID_len);
vp = find_varbind_in_list (varlist, anOID, anOID_len);
if (vp) {
memcpy(model,vp->val.string,vp->val_len);
model[vp->val_len] = '\0';
printf( "%s: Found model: %s\n", __func__, model);
}
} else if (op == NETSNMP_CALLBACK_OP_TIMED_OUT) {
printf("\n NETSNMP_CALLBACK_OP_TIMED_OUT\n");
return 1;
}
printf(" **************** end snmp_input **************\n ");
return 0;
} /* end snmp_input() */
netsnmp_session* ConnectionRouter(char *Community,char *sPathMib,char *Error)
{
/*
* open an SNMP session
*/
netsnmp_session *pSessionOpen = NULL;
// a voir
//static
netsnmp_session pSession;
putenv(strdup("POSIXLY_CORRECT=1"));
setenv("MIBS", "ALL", 1);
setenv("MIBDIRS", sPathMib, 1);
snmp_sess_init((netsnmp_session*)&pSession);
init_snmp("snmpapp");
pSession.version = SNMP_VERSION_2c;
pSession.community= (unsigned char*)Community;
pSession.community_len = strlen(Community);
unsigned long ulIp0,ulIp1,ulIp2,ulIp3;
char szAdrIp[50];
ulIp3 = (ulIpAddr&0xFF000000)>>24;
ulIp2 = (ulIpAddr&0x00FF0000)>>16;
ulIp1 = (ulIpAddr&0x0000FF00)>>8;
ulIp0 = (ulIpAddr&0x000000FF);
ulIp0 = ulIp1 = ulIp2 = ulIp3 = 255;
sprintf(szAdrIp,"%d.%d.%d.%d:161", ulIp3, ulIp2, ulIp1, ulIp0);
pSession.peername = szAdrIp;
if ((ulIp3==255)&&(ulIp2==255)&&(ulIp1==255)&&(ulIp0==255))
pSession.flags |= SNMP_FLAGS_UDP_BROADCAST;
pSession.callback = snmp_input;
pSession.callback_magic = NULL;
SOCK_STARTUP;
pSessionOpen = snmp_open(&pSession);
if (pSessionOpen == NULL)
{
SOCK_CLEANUP;
sprintf(Error,"Error can not open Snmp Session!!!");
return NULL;
}
return pSessionOpen;
}
// ferme la session Snmp ouverte
int ClearRouter(netsnmp_session* pSession)
{
snmp_close(pSession);
SOCK_CLEANUP;
return 0;
}
void fct_listen1(evutil_socket_t listener,short event, void *arg)
{
struct event_base *base = (struct event_base *)arg;
printf("\n fct_listen=%d\n",event);
if (event == 2) snmp_read();
else if (event==1)
{
snmp_timeout();
printf("snmp_timeout\n");
event_base_loopbreak(base);
}
}
// callback function calling when socket is up (trame detected)
void fct_listen(evutil_socket_t listener,short event, void *arg)
{
struct event_base *base = (struct event_base *)arg;
printf("\n fct_listen=%d\n",event);
int fds = 0, block = 0;
fd_set fdset;
struct timeval timeout; // timeout for select()
timeout.tv_sec = 0;
timeout.tv_usec = 10000;
FD_ZERO (&fdset);
snmp_select_info (&fds, &fdset, &timeout, &block);
fds = select (fds, &fdset, NULL, NULL, &timeout);
if (fds)
{ snmp_read(&fdset);
}
else
{
snmp_timeout();
printf("snmp_timeout\n");
// stop evenet loop
event_base_loopbreak(base);
}
}
// main
int main(int argc, char** argv)
{
netsnmp_session *pSession;
netsnmp_pdu *pdu, *response = NULL;
oid name[MAX_OID_LEN];
size_t name_length;
char sError[200];
time_t endtime;
struct timeval five_seconds = {5,0};
//struct event_base *base;
struct event* wait;
// create Event base
Sample_EventBase = event_base_new();
if (!Sample_EventBase)
{
cout << "event_base_new() returned NULL" << endl;
exit(1);
}
pSession = ConnectionRouter("public","c:\\mibs",sError);
if (pSession != NULL)
{
// recover socket
netsnmp_transport *ptr = snmp_sess_transport(snmp_sess_pointer(pSession));
// register event callback
wait = event_new(Sample_EventBase,ptr->sock,EV_READ|EV_PERSIST,fct_listen,(void*)Sample_EventBase);
// event timeout timer
event_add(wait, &five_seconds);
pdu = snmp_pdu_create(SNMP_MSG_GET);
name_length = MAX_OID_LEN;
if (!snmp_parse_oid("system.sysDescr.0", name, &name_length)) {
printf("\nsnmp error");
} else
snmp_add_null_var(pdu, name, name_length);
if (!snmp_parse_oid("system.sysObjectID.0", name, &name_length)) {
printf("\nsnmp error");
} else
snmp_add_null_var(pdu, name, name_length);
if (!snmp_send(pSession,pdu))
{
snmp_free_pdu(pdu);
}
else
{
//event_base LOOP
event_base_dispatch(Sample_EventBase);
cout << "\nExit event loop\n" << endl;
}
printf("\n aa\n");
ClearRouter(pSession);
printf("\n fin\n");
}
// free event base
printf("\n free\n");
if(Sample_EventBase)
{
event_base_free(Sample_EventBase);
Sample_EventBase = NULL;
printf("\n OK\n");
}
cout << "Terminated!!!" << endl;
return 0;
}
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