[ nagiosplug-Bugs-3503921 ] check_dhcp.c incorrectly setting source ip address as siaddr
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Bugs item #3503921, was opened at 2012-03-13 16:16 Message generated for change (Comment added) made by infotek411 You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=397597&aid=3503921&group_id=29880 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: General plugin execution Group: release-1.4.15 Status: Open Resolution: None Priority: 5 Private: No Submitted By: [email protected] () Assigned to: Nobody/Anonymous (nobody) 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@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 [email protected] if(offer_packet.siaddr.s_addr != 0L){ source.sin_addr.s_addr = offer_packet.siaddr.s_addr ; } */ ---------------------------------------------------------------------- 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 [email protected] 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: [email protected] () 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@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: [email protected] () 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@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: [email protected] () Date: 2012-03-13 16:22 Message: was trying to use google login... Jason Ellison [email protected] ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=397597&aid=3503921&group_id=29880 ------------------------------------------------------------------------------ Better than sec? Nothing is better than sec when it comes to monitoring Big Data applications. Try Boundary one-second resolution app monitoring today. Free. http://p.sf.net/sfu/Boundary-dev2dev _______________________________________________________ Nagios Plugin Development Mailing List Nagiosplug-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Unsubscribe at https://lists.sourceforge.net/lists/listinfo/nagiosplug-devel ::: Please include plugins version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null