[Nagiosplug-devel] [ nagiosplug-Bugs-3503921 ] check_dhcp.c incorrectly setting source ip address as siaddr
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Fri May 10 23:56:30 CEST 2013
Bugs item #3503921, was opened at 2012-03-13 16:16
Message generated for change (Comment added) made by armandelli
You can respond by visiting:
https://sourceforge.net/tracker/?func=detail&atid=397597&aid=3503921&group_id=29880
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Category: General plugin execution
Group: release-1.4.15
Status: Closed
Resolution: Accepted
Priority: 5
Private: No
Submitted By: infotek at gmail.com ()
Assigned to: Holger Weiss (hweiss)
Summary: check_dhcp.c incorrectly setting source ip address as siaddr
Initial Comment:
nagios-plugins-1.4.15
plugins-root/check_dhcp.c
Sets dhcp server source ip to the next server (siaddr) IP address,
causing -s to fail to operate as expected.
-s, --serverip=IPADDRESS
IP address of DHCP server that we must hear from
root at nagios:/usr/local/src/nagios-plugins-1.4.15# ./plugins-root/check_dhcp -v
DHCP socket: 3
Hardware address: 00:22:19:56:99:48
DHCPDISCOVER to 255.255.255.255 port 67
DHCPDISCOVER XID: 275057756 (0x10650C5C)
DHCDISCOVER ciaddr: 0.0.0.0
DHCDISCOVER yiaddr: 0.0.0.0
DHCDISCOVER siaddr: 0.0.0.0
DHCDISCOVER giaddr: 0.0.0.0
send_dhcp_packet result: 548
recv_result_1: 300
recv_result_2: 300
receive_dhcp_packet() result: 300
receive_dhcp_packet() source: 10.10.10.15
Result=OK
DHCPOFFER from IP address 10.10.10.15 via 10.10.10.15
DHCPOFFER XID: 275057756 (0x10650C5C)
DHCPOFFER chaddr: 002219569948
DHCPOFFER ciaddr: 0.0.0.0
DHCPOFFER yiaddr: 10.10.10.166
DHCPOFFER siaddr: 10.10.10.24
DHCPOFFER giaddr: 0.0.0.0
Option: 53 (0x01)
Option: 1 (0x04)
Option: 58 (0x04)
Option: 59 (0x04)
Lease Time: 0 seconds
Renewal Time: 14400 seconds
Rebinding Time: 25200 seconds
Added offer from server @ 10.10.10.15 of IP address 10.10.10.166
No (more) data received (nfound: 0)
Result=ERROR
Total responses seen on the wire: 1
Valid responses for this machine: 1
OK: Received 1 DHCPOFFER(s), max lease time = 0 sec.
17:58:55.805403 IP (tos 0x0, ttl 128, id 20477, offset 0, flags
[none], proto UDP (17), length 328)
10.10.10.15.67 > 255.255.255.255.68: [udp sum ok] BOOTP/DHCP,
Reply, length 300, xid 0x10650c5c, Flags [none] (0x0000)
Your-IP 10.10.10.166
Server-IP 10.10.10.24
Client-Ethernet-Address 00:22:19:56:99:48
file "kbox2000.0"
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Offer
Subnet-Mask Option 1, length 4: 255.255.255.0
RN Option 58, length 4: 14400
RB Option 59, length 4: 25200
Lease-Time Option 51, length 4: 28800
Server-ID Option 54, length 4: 10.10.10.15
0x0000: 4500 0148 4ffd 0000 8011 d58f 0a0a 0a0f
0x0010: ffff ffff 0043 0044 0134 2e43 0201 0600
0x0020: 1065 0c5c 0000 0000 0000 0000 0a0a 0aa6
0x0030: 0a0a 0a18 0000 0000 0022 1956 9948 0000
0x0040: 0000 0000 0000 0000 0000 0000 0000 0000
0x0050: 0000 0000 0000 0000 0000 0000 0000 0000
0x0060: 0000 0000 0000 0000 0000 0000 0000 0000
0x0070: 0000 0000 0000 0000 0000 0000 0000 0000
0x0080: 0000 0000 0000 0000 6b62 6f78 3230 3030
0x0090: 2e30 0000 0000 0000 0000 0000 0000 0000
0x00a0: 0000 0000 0000 0000 0000 0000 0000 0000
0x00b0: 0000 0000 0000 0000 0000 0000 0000 0000
0x00c0: 0000 0000 0000 0000 0000 0000 0000 0000
0x00d0: 0000 0000 0000 0000 0000 0000 0000 0000
0x00e0: 0000 0000 0000 0000 0000 0000 0000 0000
0x00f0: 0000 0000 0000 0000 0000 0000 0000 0000
0x0100: 0000 0000 0000 0000 6382 5363 3501 0201
0x0110: 04ff ffff 003a 0400 0038 403b 0400 0062
0x0120: 7033 0400 0070 8036 040a 0a0a 0fff 0000
0x0130: 0000 0000 0000 0000 0000 0000 0000 0000
0x0140: 0000 0000 0000 0000
plugins-root/check_dhcp.c
FIX
/* If siaddr is non-zero, set "source" to siaddr */
/* don't set the source to next boot server (siaddr) 591 infotek at gmail.com
if(offer_packet.siaddr.s_addr != 0L){
source.sin_addr.s_addr = offer_packet.siaddr.s_addr ;
}
*/
----------------------------------------------------------------------
Comment By: andre pinho (armandelli)
Date: 2013-05-10 14:56
Message:
Hi guys! First timer on the forum, got a quick noob question. I just
started working with nagios and programming and would like to know how do I
aplly tha fix posted below?
I tried executing the file in the nagios plugin folder and it did not work.
Thanks a lot!
Andre.
----------------------------------------------------------------------
Comment By: Holger Weiss (hweiss)
Date: 2012-06-13 15:44
Message:
This problem is now fixed in Git. Thank you for your report.
----------------------------------------------------------------------
Comment By: Jason Ellison (infotek411)
Date: 2012-04-12 22:30
Message:
the following is a more correct in dealing with the 0x00 PAD octets... if
value = 0 skip one octet else it was just an unknown value and you can skip
option_length.
@@ -870,9 +865,9 @@
memcpy(&serv_ident.s_addr,
&offer_packet->options[x],sizeof(serv_ident.s_addr));
break;
}
-
- /* skip option data we're ignoring */
- if(option_type!=DHCP_OPTION_REBINDING_TIME)
+ if(option_type=0)
+ x+=1;
+ else
x+=option_length;
}
----------------------------------------------------------------------
Comment By: Jason Ellison (infotek411)
Date: 2012-04-12 21:07
Message:
That did solve the abort issue when parsing the options, which in turn
allowed serv_ident to be set. It brought out a bug in the OPTION parsing
in the switch while in verbose mode
I also got rid of the source = siaddr.
--- ./a/plugins-root/check_dhcp.c 2010-07-27 15:47:16.000000000 -0500
+++ ./b/plugins-root/check_dhcp.c 2012-04-12 22:58:56.000000000 -0500
@@ -141,7 +141,7 @@
u_int16_t flags; /* flags */
struct in_addr ciaddr; /* IP address of this machine (if
we already have one) */
struct in_addr yiaddr; /* IP address of this machine
(offered by the DHCP server) */
- struct in_addr siaddr; /* IP address of DHCP server */
+ struct in_addr siaddr; /* IP address of next server */
struct in_addr giaddr; /* IP address of DHCP relay */
unsigned char chaddr [MAX_DHCP_CHADDR_LENGTH]; /* hardware
address of this machine */
char sname [MAX_DHCP_SNAME_LENGTH]; /* name of DHCP server */
@@ -587,11 +587,6 @@
/* Save a copy of "source" into "via" even if it's via
itself */
memcpy(&via,&source,sizeof(source)) ;
- /* If siaddr is non-zero, set "source" to siaddr */
- if(offer_packet.siaddr.s_addr != 0L){
- source.sin_addr.s_addr = offer_packet.siaddr.s_addr
;
- }
-
if(verbose){
printf(_("DHCPOFFER from IP address
%s"),inet_ntoa(source.sin_addr));
printf(_(" via %s\n"),inet_ntoa(via.sin_addr));
@@ -840,7 +835,7 @@
for(x=4;x<MAX_DHCP_OPTIONS_LENGTH;){
/* end of options (0 is really just a pad, but bail out
anyway) */
- if((int)offer_packet->options[x]==-1 ||
(int)offer_packet->options[x]==0)
+ if((int)offer_packet->options[x]==-1)
break;
/* get option type */
@@ -870,10 +865,7 @@
memcpy(&serv_ident.s_addr,
&offer_packet->options[x],sizeof(serv_ident.s_addr));
break;
}
-
- /* skip option data we're ignoring */
- if(option_type!=DHCP_OPTION_REBINDING_TIME)
- x+=option_length;
+ x+=option_length;
}
if(verbose){
@@ -903,9 +895,9 @@
* the next bootstrap service (e.g., delivery of an operating
system
* executable image). A DHCP server always returns its own address
in
* the 'server identifier' option." 'serv_ident' is the 'server
- * identifier' option, 'source' is the 'siaddr' field or (if
'siaddr'
- * wasn't available) the IP address we received the DHCPOFFER from.
If
- * 'serv_ident' isn't available for some reason, we use 'source'.
+ * identifier' option, 'source' is the IP address we received the
+ * DHCPOFFER from. If 'serv_ident' isn't available for some
reason, we
+ * use 'source'.
*/
new_offer->server_address=serv_ident.s_addr?serv_ident:source;
new_offer->offered_address=offer_packet->yiaddr;
----------------------------------------------------------------------
Comment By: Holger Weiss (hweiss)
Date: 2012-04-11 11:04
Message:
Thank you very much.
I've attached a patch, could you check whether it solves the problem?
----------------------------------------------------------------------
Comment By: Jason Ellison (infotek411)
Date: 2012-04-10 21:02
Message:
gdb inspecting the local variables before it is source is clobbered by
siaddr
Breakpoint 1, get_dhcp_offer (sock=6) at check_dhcp.c:591
591 if(offer_packet.siaddr.s_addr != 0L){
after source is clobbered by siaddr
Breakpoint 2, get_dhcp_offer (sock=6) at check_dhcp.c:595
595 if(verbose){
and before and after the conditional expression that sets source
Breakpoint 3, add_dhcp_offer (source={s_addr = 403311114},
offer_packet=0xbf9d7460) at check_dhcp.c:910
910
new_offer->server_address=serv_ident.s_addr?serv_ident:source;
Breakpoint 4, add_dhcp_offer (source={s_addr = 403311114},
offer_packet=0xbf9d7460) at check_dhcp.c:917
917 if(verbose){
# gdb ./plugins-root/check_dhcp
GNU gdb 6.8
Copyright (C) 2008 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later
<http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "i486-slackware-linux"...
(gdb) set args -v
(gdb) break 590
Breakpoint 1 at 0x804a808: file check_dhcp.c, line 590.
(gdb) break 595
Breakpoint 2 at 0x804a815: file check_dhcp.c, line 595.
(gdb) break 910
Breakpoint 3 at 0x8049e56: file check_dhcp.c, line 910.
(gdb) break 917
Breakpoint 4 at 0x8049e83: file check_dhcp.c, line 917.
(gdb) start
Breakpoint 5 at 0x804aeb8: file check_dhcp.c, line 262.
Starting program:
/usr/local/src/nagios-plugins-1.4.15/plugins-root/check_dhcp -v
[Thread debugging using libthread_db enabled]
[New Thread 0xb7e466c0 (LWP 21323)]
[Switching to Thread 0xb7e466c0 (LWP 21323)]
main (argc=2, argv=0xbfd162c4) at check_dhcp.c:262
262 setlocale (LC_ALL, "");
(gdb) continue
Continuing.
DHCP socket: 6
Hardware address: 00:22:19:56:99:48
DHCPDISCOVER to 255.255.255.255 port 67
DHCPDISCOVER XID: 8454682 (0x81021A)
DHCDISCOVER ciaddr: 0.0.0.0
DHCDISCOVER yiaddr: 0.0.0.0
DHCDISCOVER siaddr: 0.0.0.0
DHCDISCOVER giaddr: 0.0.0.0
send_dhcp_packet result: 548
recv_result_1: 300
recv_result_2: 300
receive_dhcp_packet() result: 300
receive_dhcp_packet() source: 10.10.10.15
Result=OK
Breakpoint 1, get_dhcp_offer (sock=6) at check_dhcp.c:591
591 if(offer_packet.siaddr.s_addr != 0L){
(gdb) info locals
offer_packet = {op = 2 '\002', htype = 1 '\001', hlen = 6 '\006', hops = 0
'\0', xid = 436371712, secs = 0, flags = 0, ciaddr = {s_addr = 0}, yiaddr =
{s_addr = 1879706122},
siaddr = {s_addr = 403311114}, giaddr = {s_addr = 0}, chaddr =
"\000\"\031V\231H\000\000\000\000\000\000\000\000\000", sname = '\0'
<repeats 63 times>,
file = "kbox2000.0", '\0' <repeats 117 times>,
options =
"c\202Sc5\001\002\001\004ÿÿÿ\000:\004\000\0008@;\004\000\000bp3\004\000\000p\2006\004\n\n\n\017ÿ",
'\0' <repeats 273 times>}
source = {sin_family = 2, sin_port = 17152, sin_addr = {s_addr =
252316170}, sin_zero = "\000\000\000\000\000\000\000"}
via = {sin_family = 2, sin_port = 17152, sin_addr = {s_addr = 252316170},
sin_zero = "\000\000\000\000\000\000\000"}
result = 0
responses = 1
x = 6
start_time = 1334116496
current_time = <value optimized out>
(gdb) continue
Continuing.
Breakpoint 2, get_dhcp_offer (sock=6) at check_dhcp.c:595
595 if(verbose){
(gdb) info locals
offer_packet = {op = 2 '\002', htype = 1 '\001', hlen = 6 '\006', hops = 0
'\0', xid = 436371712, secs = 0, flags = 0, ciaddr = {s_addr = 0}, yiaddr =
{s_addr = 1879706122},
siaddr = {s_addr = 403311114}, giaddr = {s_addr = 0}, chaddr =
"\000\"\031V\231H\000\000\000\000\000\000\000\000\000", sname = '\0'
<repeats 63 times>,
file = "kbox2000.0", '\0' <repeats 117 times>,
options =
"c\202Sc5\001\002\001\004ÿÿÿ\000:\004\000\0008@;\004\000\000bp3\004\000\000p\2006\004\n\n\n\017ÿ",
'\0' <repeats 273 times>}
source = {sin_family = 2, sin_port = 17152, sin_addr = {s_addr =
403311114}, sin_zero = "\000\000\000\000\000\000\000"}
via = {sin_family = 2, sin_port = 17152, sin_addr = {s_addr = 252316170},
sin_zero = "\000\000\000\000\000\000\000"}
result = 0
responses = 1
x = 6
start_time = 1334116496
current_time = <value optimized out>
(gdb) continue
Continuing.
DHCPOFFER from IP address 10.10.10.24 via 10.10.10.15
DHCPOFFER XID: 8454682 (0x81021A)
DHCPOFFER chaddr: 002219569948
DHCPOFFER ciaddr: 0.0.0.0
DHCPOFFER yiaddr: 10.10.10.112
DHCPOFFER siaddr: 10.10.10.24
DHCPOFFER giaddr: 0.0.0.0
Option: 53 (0x01)
Option: 1 (0x04)
Option: 58 (0x04)
Option: 59 (0x04)
Lease Time: 0 seconds
Renewal Time: 14400 seconds
Rebinding Time: 25200 seconds
Breakpoint 3, add_dhcp_offer (source={s_addr = 403311114},
offer_packet=0xbfd15fa0) at check_dhcp.c:910
910
new_offer->server_address=serv_ident.s_addr?serv_ident:source;
(gdb) info locals
x = <value optimized out>
option_type = 25200
option_length = 4
serv_ident = {s_addr = 0}
(gdb) continue
Continuing.
Breakpoint 4, add_dhcp_offer (source={s_addr = 403311114},
offer_packet=0xbfd15fa0) at check_dhcp.c:917
917 if(verbose){
(gdb) info locals
x = <value optimized out>
option_type = 25200
option_length = 4
serv_ident = {s_addr = 0}
(gdb) continue
Continuing.
Added offer from server @ 10.10.10.24 of IP address 10.10.10.112
Total responses seen on the wire: 1
Valid responses for this machine: 1
OK: Received 1 DHCPOFFER(s), max lease time = 0 sec.
Program exited normally.
(gdb) quit
tcpdump (saved the pcap also)
root at nagios:/usr/local/src/nagios-plugins-1.4.15# tcpdump -nvvvxX -r
check_dhcp.pcap
reading from file check_dhcp.pcap, link-type EN10MB (Ethernet)
22:28:36.929010 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP
(17), length 576)
10.10.10.26.68 > 255.255.255.255.67: [bad udp cksum e6d!] BOOTP/DHCP,
Request from 00:22:19:56:99:48, length 548, xid 0x6247da8b, secs 65280,
Flags [Broadcast] (0x8000)
Client-Ethernet-Address 00:22:19:56:99:48
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
END Option 255, length 0
PAD Option 0, length 0, occurs 304
0x0000: 4500 0240 0000 4000 4011 248a 0a0a 0a1a E.. at ..@. at .$.....
0x0010: ffff ffff 0044 0043 022c 1661 0101 0600 .....D.C.,.a....
0x0020: 6247 da8b ff00 8000 0000 0000 0000 0000 bG..............
0x0030: 0000 0000 0000 0000 0022 1956 9948 0000 .........".V.H..
0x0040: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0050: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0060: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0070: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0080: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0090: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00a0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00b0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00c0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00d0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00e0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00f0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0100: 0000 0000 0000 0000 6382 5363 3501 01ff ........c.Sc5...
0x0110: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0120: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0130: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0140: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0150: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0160: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0170: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0180: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0190: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x01a0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x01b0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x01c0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x01d0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x01e0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x01f0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0200: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0210: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0220: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0230: 0000 0000 0000 0000 0000 0000 0000 0000 ................
22:28:36.929258 IP (tos 0x0, ttl 128, id 22737, offset 0, flags [none],
proto UDP (17), length 328)
10.10.10.15.67 > 255.255.255.255.68: [udp sum ok] BOOTP/DHCP, Reply,
length 300, xid 0x6247da8b, Flags [none] (0x0000)
Your-IP 10.10.10.112
Server-IP 10.10.10.24
Client-Ethernet-Address 00:22:19:56:99:48
file "kbox2000.0"
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Offer
Subnet-Mask Option 1, length 4: 255.255.255.0
RN Option 58, length 4: 14400
RB Option 59, length 4: 25200
Lease-Time Option 51, length 4: 28800
Server-ID Option 54, length 4: 10.10.10.15
END Option 255, length 0
PAD Option 0, length 0, occurs 26
0x0000: 4500 0148 58d1 0000 8011 ccbb 0a0a 0a0f E..HX...........
0x0010: ffff ffff 0043 0044 0134 0e67 0201 0600 .....C.D.4.g....
0x0020: 6247 da8b 0000 0000 0000 0000 0a0a 0a70 bG.............p
0x0030: 0a0a 0a18 0000 0000 0022 1956 9948 0000 .........".V.H..
0x0040: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0050: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0060: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0070: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0080: 0000 0000 0000 0000 6b62 6f78 3230 3030 ........kbox2000
0x0090: 2e30 0000 0000 0000 0000 0000 0000 0000 .0..............
0x00a0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00b0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00c0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00d0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00e0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00f0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0100: 0000 0000 0000 0000 6382 5363 3501 0201 ........c.Sc5...
0x0110: 04ff ffff 003a 0400 0038 403b 0400 0062 .....:...8@;...b
0x0120: 7033 0400 0070 8036 040a 0a0a 0fff 0000 p3...p.6........
0x0130: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0140: 0000 0000 0000 0000 ........
----------------------------------------------------------------------
Comment By: Holger Weiss (hweiss)
Date: 2012-04-10 15:17
Message:
Hmm. As I said, I agree that the plugin's interpretation of the "siaddr"
field is wrong. However, from reading the code, I wouldn't have expected
the behavior you're reporting unless the "server identifier" option isn't
set. So, I'd like to understand what's going on.
Could you attach the dump of a DHCP session initiated by check_dhcp?
----------------------------------------------------------------------
Comment By: Jason Ellison (infotek411)
Date: 2012-04-10 14:59
Message:
In the tcpdump you can see the Server-ID (option 54) was set to 10.10.10.15
Server-ID Option 54, length 4: 10.10.10.15
0x36 (54) lenght 04 0a(10) 0a(10) 0a(10) 0f(15)
0x0120: 7033 0400 0070 8036 040a 0a0a 0f
It appears to me that there is confusion of "Server Identifier" and
"Server IP" that only comes up when one is using an siaddr.
http://www.ietf.org/rfc/rfc2131.txt
DHCP clarifies the interpretation of the 'siaddr' field as the
address of the server to use in the next step of the client's
bootstrap process. A DHCP server may return its own address in the
'siaddr' field, if the server is prepared to supply the next
bootstrap service (e.g., delivery of an operating system executable
image). A DHCP server always returns its own address in the 'server
identifier' option.
siaddr 4 IP address of next server to use in bootstrap;
returned in DHCPOFFER, DHCPACK by server.
----------------------------------------------------------------------
Comment By: Jason Ellison (infotek411)
Date: 2012-04-10 13:47
Message:
Server is a Windows 2003 DHCP server with next-server "siaddr" set for PXE
boot.
----------------------------------------------------------------------
Comment By: Andy ()
Date: 2012-04-09 08:00
Message:
I get the "wrong" response without the above change also. DHCP is Windows
Server 2008 R1 (actually SBS). We have a PXE Boot server and the check_dhcp
thinks the PXE Boot is the actual server, which fails.
----------------------------------------------------------------------
Comment By: Holger Weiss (hweiss)
Date: 2012-03-14 10:31
Message:
What sort of DHCP server are you running? The plugin will only use
"siaddr" in this way if the mandatory "server identifier" option is missing
from the server's response.
It seems the current code tried to fix some problem which showed up in
certain environments with DHCP relays involved. However, in principle I
agree that the plugin's interpretation of the "siaddr" field isn't correct.
----------------------------------------------------------------------
Comment By: Jason Ellison (infotek411)
Date: 2012-03-13 17:27
Message:
diff --git a/a/plugins-root/check_dhcp.c b/b/plugins-root/check_dhcp.c
index 2a1875c..b7f695b 100644
--- a/a/plugins-root/check_dhcp.c
+++ b/b/plugins-root/check_dhcp.c
@@ -588,10 +588,11 @@ int get_dhcp_offer(int sock){
memcpy(&via,&source,sizeof(source)) ;
/* If siaddr is non-zero, set "source" to siaddr */
+/* don't set the source to next boot server (siaddr) 591 infotek at gmail.com
if(offer_packet.siaddr.s_addr != 0L){
source.sin_addr.s_addr = offer_packet.siaddr.s_addr
;
}
-
+*/
if(verbose){
printf(_("DHCPOFFER from IP address
%s"),inet_ntoa(source.sin_addr));
printf(_(" via %s\n"),inet_ntoa(via.sin_addr));
----------------------------------------------------------------------
Comment By: Jason Ellison (infotek411)
Date: 2012-03-13 17:03
Message:
I verified that I can check remote DHCP servers correctly after applying
the fix. Options used were "check_dhcp -u -s 10.10.10.15".
----------------------------------------------------------------------
Comment By: infotek at gmail.com ()
Date: 2012-03-13 16:47
Message:
Example of -s being specified correctly in verbose mode. Fails because
siaddr (10.10.10.24) is copied over source (10.10.10.15).
root at nagios:/usr/local/src/nagios-plugins-1.4.15# ./plugins-root/check_dhcp
-v -s 10.10.10.15
Requested server address: 10.10.10.15
DHCP socket: 3
Hardware address: 00:22:19:56:99:48
DHCPDISCOVER to 255.255.255.255 port 67
DHCPDISCOVER XID: 513242689 (0x1E977641)
DHCDISCOVER ciaddr: 0.0.0.0
DHCDISCOVER yiaddr: 0.0.0.0
DHCDISCOVER siaddr: 0.0.0.0
DHCDISCOVER giaddr: 0.0.0.0
send_dhcp_packet result: 548
recv_result_1: 300
recv_result_2: 300
receive_dhcp_packet() result: 300
receive_dhcp_packet() source: 10.10.10.15
Result=OK
DHCPOFFER from IP address 10.10.10.24 via 10.10.10.15
DHCPOFFER XID: 513242689 (0x1E977641)
DHCPOFFER chaddr: 002219569948
DHCPOFFER ciaddr: 0.0.0.0
DHCPOFFER yiaddr: 10.10.10.166
DHCPOFFER siaddr: 10.10.10.24
DHCPOFFER giaddr: 0.0.0.0
Option: 53 (0x01)
Option: 1 (0x04)
Option: 58 (0x04)
Option: 59 (0x04)
Lease Time: 0 seconds
Renewal Time: 14400 seconds
Rebinding Time: 25200 seconds
Added offer from server @ 10.10.10.24 of IP address 10.10.10.166
No (more) data received (nfound: 0)
Result=ERROR
Total responses seen on the wire: 1
Valid responses for this machine: 1
CRITICAL: Received 1 DHCPOFFER(s), 0 of 1 requested servers responded, max
lease time = 0 sec.
----------------------------------------------------------------------
Comment By: infotek at gmail.com ()
Date: 2012-03-13 16:33
Message:
The ticket contains the output of check_dhcp after I fixed it (oops).
Sorry :(
Jason Ellison
Below is the output from an unmodified version of check_dhcp :
root at nagios:/usr/local/src/nagios-plugins-1.4.15# ./plugins-root/check_dhcp
-v
DHCP socket: 3
Hardware address: 00:22:19:56:99:48
DHCPDISCOVER to 255.255.255.255 port 67
DHCPDISCOVER XID: 1292513780 (0x4D0A31F4)
DHCDISCOVER ciaddr: 0.0.0.0
DHCDISCOVER yiaddr: 0.0.0.0
DHCDISCOVER siaddr: 0.0.0.0
DHCDISCOVER giaddr: 0.0.0.0
send_dhcp_packet result: 548
recv_result_1: 300
recv_result_2: 300
receive_dhcp_packet() result: 300
receive_dhcp_packet() source: 10.10.10.15
Result=OK
DHCPOFFER from IP address 10.10.10.24 via 10.10.10.15
DHCPOFFER XID: 1292513780 (0x4D0A31F4)
DHCPOFFER chaddr: 002219569948
DHCPOFFER ciaddr: 0.0.0.0
DHCPOFFER yiaddr: 10.10.10.166
DHCPOFFER siaddr: 10.10.10.24
DHCPOFFER giaddr: 0.0.0.0
Option: 53 (0x01)
Option: 1 (0x04)
Option: 58 (0x04)
Option: 59 (0x04)
Lease Time: 0 seconds
Renewal Time: 14400 seconds
Rebinding Time: 25200 seconds
Added offer from server @ 10.10.10.24 of IP address 10.10.10.166
No (more) data received (nfound: 0)
Result=ERROR
Total responses seen on the wire: 1
Valid responses for this machine: 1
OK: Received 1 DHCPOFFER(s), max lease time = 0 sec.
----------------------------------------------------------------------
Comment By: infotek at gmail.com ()
Date: 2012-03-13 16:22
Message:
was trying to use google login...
Jason Ellison infotek at gmail.com
----------------------------------------------------------------------
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