int main(int argc, char **argv){
int dhcp_socket;
int result;
if(process_arguments(argc,argv)!=OK){
/*usage("Invalid command arguments supplied\n");*/
printf("Invalid command arguments supplied\n");
exit(STATE_UNKNOWN);
}
/* create socket for DHCP communications */
dhcp_socket=create_dhcp_socket();
/* get hardware address of client machine */
get_hardware_address(dhcp_socket,network_interface_name);
/* send DHCPDISCOVER packet */
send_dhcp_discover(dhcp_socket);
/* wait for a DHCPOFFER packet */
get_dhcp_offer(dhcp_socket);
/* close socket we created */
close_dhcp_socket(dhcp_socket);
/* determine state/plugin output to return */
result=get_results();
/* free allocated memory */
free_dhcp_offer_list();
free_requested_server_list();
return result;
}
int main(int argc, char **argv){
int dhcp_socket;
int result = STATE_UNKNOWN;
setlocale (LC_ALL, "");
bindtextdomain (PACKAGE, LOCALEDIR);
textdomain (PACKAGE);
/* Parse extra opts if any */
argv=np_extra_opts(&argc, argv, progname);
if(process_arguments(argc,argv)!=OK){
usage4 (_("Could not parse arguments"));
}
/* this plugin almost certainly needs root permissions. */
np_warn_if_not_root();
/* create socket for DHCP communications */
dhcp_socket=create_dhcp_socket();
/* get hardware address of client machine */
if(user_specified_mac!=NULL)
memcpy(client_hardware_address,user_specified_mac,6);
else
get_hardware_address(dhcp_socket,network_interface_name);
if(unicast) /* get IP address of client machine */
get_ip_address(dhcp_socket,network_interface_name);
/* send DHCPDISCOVER packet */
send_dhcp_discover(dhcp_socket);
/* wait for a DHCPOFFER packet */
get_dhcp_offer(dhcp_socket);
/* close socket we created */
close_dhcp_socket(dhcp_socket);
/* determine state/plugin output to return */
result=get_results();
/* free allocated memory */
free_dhcp_offer_list();
free_requested_server_list();
return result;
}
// Initial_tid can be a random number for every board. E.g the last digit
// of the mac address. It is not so important that the number is random.
// It is more important that it is unique and no other board on the same
// Lan has the same number. This is because there might be a power outage
// and all boards reboot afterwards at the same time. At that moment they
// must all have different TIDs otherwise there will be an IP address mess-up.
//
// The function returns 1 once we have a valid IP.
// At this point you must not call the function again.
uint8_t packetloop_dhcp_initial_ip_assignment(uint8_t *buf,uint16_t plen,uint8_t initial_tid){
static uint16_t init=0x5fff; // about 2 sec delay
uint8_t cmd;
// do nothing if the link is down
if (!enc28j60linkup()) return(0);
// first time that this function is called:
if (plen==0){
if (init==2){
init=1;
dhcp_6sec_cnt=0;
dhcp_tid=initial_tid;
// Reception of broadcast packets is turned off by default, but
// the DHCP offer message that the DHCP server sends will be
// a broadcast packet. Enable here and disable later.
enc28j60EnableBroadcast();
send_dhcp_discover(buf,dhcp_tid);
return(0);
}
if (dhcp_yiaddr[0]==0 && dhcp_6sec_cnt > 5){
// still no IP after 30 sec
dhcp_tid++;
dhcp_6sec_cnt=0;
// Reception of broadcast packets is turned off by default, but
// the DHCP offer message that the DHCP server sends will be
// a broadcast packet. Enable here and disable later.
enc28j60EnableBroadcast();
send_dhcp_discover(buf,dhcp_tid);
return(0);
}
// We have a little delay (about 2sec) at startup. Sometimes
// the power fluctuates or the programmer causes
// the board to reset and then immediately reset again.
// We wait with the sending of a send_dhcp_discover just in case
// we did already so at the last reset which was possibly less
// than a second ago.
if (init>2){
init--;
}
return(0);
}
// plen > 0
if (is_dhcp_msg_for_me(buf,plen,dhcp_tid)){
// It's really a borderline case that we the the dhcp_is_renew_tid
// function call for. It could only happen if the board is power cyceled
// during operation.
if (dhcp_is_renew_tid(buf,plen)==1) return(0); // should have been initial tid, just return
cmd=dhcp_get_message_type(buf,plen);
if (cmd==2){ // DHCPOFFER =2
init=1; // no more init needed
dhcp_get_yiaddr(buf,plen);
dhcp_option_parser(buf,plen);
// answer offer with a request:
send_dhcp_request(buf,dhcp_tid);
}
if (cmd==5){ // DHCPACK =5
// success, DHCPACK, we have the IP
init=1; // no more init needed
enc28j60DisableBroadcast();
return(1);
}
}
return(0);
}