Module: monitoring-plugins
Branch: check_dhcp_rogue_detection
Commit: 4570de440b7a0aaf74f2fd3adc1f2eac5252d332
Author: Patrick Cervicek <patr...@cervicek.de>
Committer: Lorenz Kästle <12514511+rincewinds...@users.noreply.github.com>
Date: Fri Oct 9 11:46:51 2015 +0200
URL:
https://www.monitoring-plugins.org/repositories/monitoring-plugins/commit/?id=4570de4
check_dhcp.c merged patch from #752
- added dhcp rogue detection
contributed by Patrick Cervicek (patrick AT cervicek.de)
- closes #752
---
plugins-root/check_dhcp.c | 92 ++++++++++++++++++++++++++++-------------------
1 file changed, 56 insertions(+), 36 deletions(-)
diff --git a/plugins-root/check_dhcp.c b/plugins-root/check_dhcp.c
index 2d22619..9aeff2b 100644
--- a/plugins-root/check_dhcp.c
+++ b/plugins-root/check_dhcp.c
@@ -156,6 +156,7 @@ typedef struct dhcp_offer_struct{
u_int32_t lease_time; /* lease time in seconds */
u_int32_t renewal_time; /* renewal time in seconds */
u_int32_t rebinding_time; /* rebinding time in seconds */
+ u_int8_t desired; /* is this offer desired (necessary
in exclusive mode) */
struct dhcp_offer_struct *next;
}dhcp_offer;
@@ -199,6 +200,7 @@ typedef struct requested_server_struct{
#define ETHERNET_HARDWARE_ADDRESS_LENGTH 6 /* length of Ethernet
hardware addresses */
u_int8_t unicast = 0; /* unicast mode: mimic a DHCP relay */
+u_int8_t exclusive = 0; /* exclusive mode aka "rogue DHCP server
detection" */
struct in_addr my_ip; /* our address (required for relay) */
struct in_addr dhcp_ip; /* server to query (if in unicast mode) */
unsigned char client_hardware_address[MAX_DHCP_CHADDR_LENGTH]="";
@@ -900,6 +902,7 @@ int add_dhcp_offer(struct in_addr source,dhcp_packet
*offer_packet){
new_offer->lease_time=dhcp_lease_time;
new_offer->renewal_time=dhcp_renewal_time;
new_offer->rebinding_time=dhcp_rebinding_time;
+ new_offer->desired=FALSE; /* exclusive mode: we'll check that in
get_results */
if(verbose){
@@ -945,7 +948,7 @@ int free_requested_server_list(void){
/* gets state and plugin output to return */
int get_results(void){
- dhcp_offer *temp_offer;
+ dhcp_offer *temp_offer, *undesired_offer=NULL;
requested_server *temp_server;
int result;
u_int32_t max_lease_time=0;
@@ -976,16 +979,24 @@ int get_results(void){
if(temp_server->answered)
printf(_("
(duplicate)"));
printf(_("\n"));
- }
+ }
if(temp_server->answered == FALSE){
requested_responses++;
temp_server->answered=TRUE;
- }
- }
- }
- }
-
- }
+ temp_offer->desired=TRUE;
+ }
+ }
+ }
+ }
+
+ /* exclusive mode: check for undesired offers */
+
for(temp_offer=dhcp_offer_list;temp_offer!=NULL;temp_offer=temp_offer->next) {
+ if (temp_offer->desired == FALSE) {
+ undesired_offer=temp_offer; /* Checks only for
the first undesired offer */
+ break; /* no further checks needed */
+ }
+ }
+ }
/* else check and see if we got our requested address from any server */
else{
@@ -999,8 +1010,8 @@ int get_results(void){
/* see if we got the address we requested */
if(!memcmp(&requested_address,&temp_offer->offered_address,sizeof(requested_address)))
received_requested_address=TRUE;
- }
- }
+ }
+ }
result=STATE_OK;
if(valid_responses==0)
@@ -1012,6 +1023,9 @@ int get_results(void){
else if(request_specific_address==TRUE &&
received_requested_address==FALSE)
result=STATE_WARNING;
+ if(exclusive && undesired_offer)
+ result=STATE_CRITICAL;
+
if(result==0) /* garrett honeycutt 2005 */
printf("OK: ");
else if(result==1)
@@ -1029,6 +1043,13 @@ int get_results(void){
printf(_("Received %d DHCPOFFER(s)"),valid_responses);
+
+ if(exclusive && undesired_offer){
+ printf(_(", Rogue DHCP Server detected! Server
%s"),inet_ntoa(undesired_offer->server_address));
+ printf(_(" offered %s
\n"),inet_ntoa(undesired_offer->offered_address));
+ return result;
+ }
+
if(requested_servers>0)
printf(_(", %s%d of %d requested servers
responded"),((requested_responses<requested_servers) &&
requested_responses>0)?"only ":"",requested_responses,requested_servers);
@@ -1071,16 +1092,16 @@ int call_getopt(int argc, char **argv){
{"interface", required_argument,0,'i'},
{"mac", required_argument,0,'m'},
{"unicast", no_argument, 0,'u'},
+ {"exclusive", no_argument, 0,'x'},
{"verbose", no_argument, 0,'v'},
{"version", no_argument, 0,'V'},
{"help", no_argument, 0,'h'},
{0,0,0,0}
};
+ int c=0;
while(1){
- int c=0;
-
-
c=getopt_long(argc,argv,"+hVvt:s:r:t:i:m:u",long_options,&option_index);
+
c=getopt_long(argc,argv,"+hVvxt:s:r:t:i:m:u",long_options,&option_index);
if(c==-1||c==EOF||c==1)
break;
@@ -1129,6 +1150,9 @@ int call_getopt(int argc, char **argv){
case 'u': /* unicast testing */
unicast=1;
break;
+ case 'x': /* exclusive testing aka "rogue DHCP server
detection" */
+ exclusive=1;
+ break;
case 'V': /* version */
print_revision(progname, NP_VERSION);
@@ -1142,10 +1166,6 @@ int call_getopt(int argc, char **argv){
verbose=1;
break;
- case '?': /* help */
- usage5 ();
- break;
-
default:
break;
}
@@ -1357,7 +1377,7 @@ void print_help(void){
printf("%s\n", _("This plugin tests the availability of DHCP servers on
a network."));
- printf ("\n\n");
+ printf ("\n\n");
print_usage();
@@ -1367,19 +1387,21 @@ void print_help(void){
printf (UT_VERBOSE);
printf (" %s\n", "-s, --serverip=IPADDRESS");
- printf (" %s\n", _("IP address of DHCP server that we must hear from"));
- printf (" %s\n", "-r, --requestedip=IPADDRESS");
- printf (" %s\n", _("IP address that should be offered by at least one
DHCP server"));
- printf (" %s\n", "-t, --timeout=INTEGER");
- printf (" %s\n", _("Seconds to wait for DHCPOFFER before timeout
occurs"));
- printf (" %s\n", "-i, --interface=STRING");
- printf (" %s\n", _("Interface to to use for listening (i.e. eth0)"));
- printf (" %s\n", "-m, --mac=STRING");
- printf (" %s\n", _("MAC address to use in the DHCP request"));
- printf (" %s\n", "-u, --unicast");
- printf (" %s\n", _("Unicast testing: mimic a DHCP relay, requires -s"));
-
- printf (UT_SUPPORT);
+ printf (" %s\n", _("IP address of DHCP server that we must hear
from"));
+ printf (" %s\n", "-r, --requestedip=IPADDRESS");
+ printf (" %s\n", _("IP address that should be offered by at least
one DHCP server"));
+ printf (" %s\n", "-t, --timeout=INTEGER");
+ printf (" %s\n", _("Seconds to wait for DHCPOFFER before timeout
occurs"));
+ printf (" %s\n", "-i, --interface=STRING");
+ printf (" %s\n", _("Interface to to use for listening (i.e. eth0)"));
+ printf (" %s\n", "-m, --mac=STRING");
+ printf (" %s\n", _("MAC address to use in the DHCP request"));
+ printf (" %s\n", "-u, --unicast");
+ printf (" %s\n", _("Unicast testing: mimic a DHCP relay, requires
-s"));
+ printf (" %s\n", "-x, --exclusive");
+ printf (" %s\n", _("Only requested DHCP server may response (rogue
DHCP server detection), requires -s"));
+
+ printf (UT_SUPPORT);
return;
}
@@ -1387,12 +1409,10 @@ void print_help(void){
void
print_usage(void){
- printf ("%s\n", _("Usage:"));
- printf (" %s [-v] [-u] [-s serverip] [-r requestedip] [-t
timeout]\n",progname);
- printf (" [-i interface] [-m mac]\n");
+ printf ("%s\n", _("Usage:"));
+ printf (" %s [-v] [-u] [-x] [-s serverip] [-r requestedip] [-t
timeout]\n",progname);
+ printf (" [-i interface] [-m mac]\n");
return;
}
-
-
