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The DHCP server now responds to DHCPLEASEQUERY messages from agents using

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IP addresses not covered by a subnet in configuration. Server also returns
vendor-class-id option, if client sent it. [ISC-Bugs #21094]
This commit is contained in:
Tomek Mrugalski 2011-04-22 13:21:35 +00:00
parent 023fbaa03e
commit 656b1ecebe
4 changed files with 110 additions and 18 deletions
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7
RELNOTES
View File

@ -99,6 +99,13 @@ work on other platforms. Please report any problems and suggested fixes to
OMAPI as a domain name, the syntax written to disk is now correctly parsed
upon restart. [ISC-Bugs #22266]
- The DHCP server now responds to DHCPLEASEQUERY messages from agents using
IP addresses not covered by a subnet in configuration. Whether or not to
respond to such an agent is still governed by the 'allow leasequery;'
configuration parameter, in the case of an agent not covered by a configured
subnet the root configuration area is examined. Server now also returns
vendor-class-id option, if client sent it. [ISC-Bugs #21094]
Changes since 4.2.0
- Documentation cleanup covering multiple tickets

14
server/dhcp.c
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@ -2329,6 +2329,20 @@ void ack_lease (packet, lease, offer, when, msg, ms_nulltp, hp)
option_chain_head_reference (&lt -> agent_options,
lease -> agent_options, MDL);
/* Save the vendor-class-identifier for DHCPLEASEQUERY. */
oc = lookup_option(&dhcp_universe, packet->options,
DHO_VENDOR_CLASS_IDENTIFIER);
if (oc != NULL &&
evaluate_option_cache(&d1, packet, NULL, NULL, packet->options,
NULL, &lease->scope, oc, MDL)) {
if (d1.len != 0) {
bind_ds_value(&lease->scope, "vendor-class-identifier",
&d1);
}
data_string_forget(&d1, MDL);
}
/* If we got relay agent information options from the packet, then
* cache them for renewal in case the relay agent can't supply them
* when the client unicasts. The options may be from an addressed

7
server/dhcpd.leases.5
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@ -28,7 +28,7 @@
.\" see ``http://www.vix.com''. To learn more about Nominum, Inc., see
.\" ``http://www.nominum.com''.
.\"
.\" $Id: dhcpd.leases.5,v 1.15 2009/11/24 02:06:57 sar Exp $
.\" $Id: dhcpd.leases.5,v 1.16 2011/04/22 13:21:35 tomasz Exp $
.\"
.TH dhcpd.leases 5
.SH NAME
@ -241,6 +241,11 @@ variable will record the name that the DHCP server used for the PTR
record. The name to which the PTR record points will be either the
\fIddns-fwd-name\fR or the \fIddns-client-fqdn\fR.
.PP
.B The \fIvendor-class-identifier\fB variable
.PP
The server retains the client-supplied Vendor Class Identifier option
for informational purposes, and to render them in DHCPLEASEQUERY responses.
.PP
.B on \fIevents\fB { \fIstatements...\fB }
The \fBon\fI statement records a list of statements to execute if a
certain event occurs. The possible events that can occur for an

96
server/dhcpleasequery.c
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@ -17,9 +17,6 @@
#include "dhcpd.h"
/*
* TODO: RFC4388 specifies that the server SHOULD store the
* vendor-class-id.
*
* TODO: RFC4388 specifies that the server SHOULD return the same
* options it would for a DHCREQUEST message, if no Parameter
* Request List option (option 55) is passed. We do not do that.
@ -145,6 +142,7 @@ dhcpleasequery(struct packet *packet, int ms_nulltp) {
unsigned char dhcpMsgType;
const char *dhcp_msg_type_name;
struct subnet *subnet;
struct group *relay_group;
struct option_state *options;
struct option_cache *oc;
int allow_leasequery;
@ -180,23 +178,26 @@ dhcpleasequery(struct packet *packet, int ms_nulltp) {
}
/*
* Set up our options, scope, and, um... stuff.
* This is basically copied from dhcpinform() in dhcp.c.
* Initially we use the 'giaddr' subnet options scope to determine if
* the giaddr-identified relay agent is permitted to perform a
* leasequery. The subnet is not required, and may be omitted, in
* which case we are essentially interrogating the root options class
* to find a globally permit.
*/
gip.len = sizeof(packet->raw->giaddr);
memcpy(gip.iabuf, &packet->raw->giaddr, sizeof(packet->raw->giaddr));
subnet = NULL;
find_subnet(&subnet, gip, MDL);
if (subnet == NULL) {
log_info("%s: unknown subnet for address %s",
msgbuf, piaddr(gip));
return;
}
if (subnet != NULL)
relay_group = subnet->group;
else
relay_group = root_group;
subnet_dereference(&subnet, MDL);
options = NULL;
if (!option_state_allocate(&options, MDL)) {
subnet_dereference(&subnet, MDL);
log_error("No memory for option state.");
log_info("%s: out of memory, no reply sent", msgbuf);
return;
@ -209,8 +210,9 @@ dhcpleasequery(struct packet *packet, int ms_nulltp) {
packet->options,
options,
&global_scope,
subnet->group,
relay_group,
NULL);
for (i=packet->class_count-1; i>=0; i--) {
execute_statements_in_scope(NULL,
packet,
@ -220,11 +222,9 @@ dhcpleasequery(struct packet *packet, int ms_nulltp) {
options,
&global_scope,
packet->classes[i]->group,
subnet->group);
relay_group);
}
subnet_dereference(&subnet, MDL);
/*
* Because LEASEQUERY has some privacy concerns, default to deny.
*/
@ -385,6 +385,30 @@ dhcpleasequery(struct packet *packet, int ms_nulltp) {
if (dhcpMsgType == DHCPLEASEACTIVE)
{
/*
* RFC 4388 uses the PRL to request options for the agent to
* receive that are "about" the client. It is confusing
* because in some cases it wants to know what was sent to
* the client (lease times, adjusted), and in others it wants
* to know information the client sent. You're supposed to
* know this on a case-by-case basis.
*
* "Name servers", "domain name", and the like from the relay
* agent's scope seems less than useful. Our options are to
* restart the option cache from the lease's best point of view
* (execute statements from the lease pool's group), or to
* simply restart the option cache from empty.
*
* I think restarting the option cache from empty best
* approaches RFC 4388's intent; specific options are included.
*/
option_state_dereference(&options, MDL);
if (!option_state_allocate(&options, MDL)) {
log_error("%s: out of memory, no reply sent", msgbuf);
lease_dereference(&lease, MDL);
return;
}
/*
* Set the hardware address fields.
@ -430,7 +454,11 @@ dhcpleasequery(struct packet *packet, int ms_nulltp) {
(lease_duration / 8);
if (time_renewal > cur_time) {
if (time_renewal < cur_time)
time_renewal = 0;
else
time_renewal = htonl(time_renewal - cur_time);
if (!add_option(options,
DHO_DHCP_RENEWAL_TIME,
&time_renewal,
@ -445,6 +473,7 @@ dhcpleasequery(struct packet *packet, int ms_nulltp) {
if (time_rebinding > cur_time) {
time_rebinding = htonl(time_rebinding - cur_time);
if (!add_option(options,
DHO_DHCP_REBINDING_TIME,
&time_rebinding,
@ -458,6 +487,14 @@ dhcpleasequery(struct packet *packet, int ms_nulltp) {
}
if (lease->ends > cur_time) {
if (time_expiry < cur_time) {
log_error("Impossible condition at %s:%d.",
MDL);
option_state_dereference(&options, MDL);
lease_dereference(&lease, MDL);
return;
}
time_expiry = htonl(lease->ends - cur_time);
if (!add_option(options,
DHO_DHCP_LEASE_TIME,
@ -471,9 +508,38 @@ dhcpleasequery(struct packet *packet, int ms_nulltp) {
}
}
/* Supply the Vendor-Class-Identifier. */
if (lease->scope != NULL) {
struct data_string vendor_class;
memset(&vendor_class, 0, sizeof(vendor_class));
if (find_bound_string(&vendor_class, lease->scope,
"vendor-class-identifier")) {
if (!add_option(options,
DHO_VENDOR_CLASS_IDENTIFIER,
(void *)vendor_class.data,
vendor_class.len)) {
option_state_dereference(&options,
MDL);
lease_dereference(&lease, MDL);
log_error("%s: error adding vendor "
"class identifier, no reply "
"sent", msgbuf);
data_string_forget(&vendor_class, MDL);
return;
}
data_string_forget(&vendor_class, MDL);
}
}
/*
* Set the relay agent info.
*
* Note that because agent info is appended without regard
* to the PRL in cons_options(), this will be sent as the
* last option in the packet whether it is listed on PRL or
* not.
*/
if (lease->agent_options != NULL) {