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- The subnet-mask option inclusion now conforms with RFC2132 section 3.3;

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it will only appear prior to the routers option if it is present on the
  Parameter-Request-List.  The subnet-mask option will also only be
  included by default (if it is not on the PRL) in response to DISCOVER
  or REQUEST messages.
  [ISC-Bugs #17117]
- The FQDN option is only supplied if the client supplied an FQDN option or
  if the FQDN option was explicitly requested on the PRL.
  [ISC-Bugs #17117]
This commit is contained in:
David Hankins 2007-10-01 16:24:44 +00:00
parent aa3e348e8b
commit e9c596456f
2 changed files with 54 additions and 8 deletions
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9
RELNOTES
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@ -225,6 +225,15 @@ suggested fixes to <dhcp-users@isc.org>.
- An assertion in lease counting relating to reserved leases was repaired.
- The subnet-mask option inclusion now conforms with RFC2132 section 3.3;
it will only appear prior to the routers option if it is present on the
Parameter-Request-List. The subnet-mask option will also only be
included by default (if it is not on the PRL) in response to DISCOVER
or REQUEST messages.
- The FQDN option is only supplied if the client supplied an FQDN option or
if the FQDN option was explicitly requested on the PRL.
Changes since 3.1.0rc1
- The parse warning that 'deny dyanmic bootp;' must be configured for

53
common/options.c
View File

@ -621,19 +621,29 @@ int cons_options (inpacket, outpacket, lease, client_state,
prl -> data [i];
}
/* If the client doesn't request this option explicitly,
/* If the client doesn't request the FQDN option explicitly,
* to indicate priority, consider it lowest priority. Fit
* in the packet if there is space.
* in the packet if there is space. Note that the option
* may only be included if the client supplied one.
*/
if (priority_len < PRIORITY_COUNT)
if ((priority_len < PRIORITY_COUNT) &&
(lookup_option(&dhcp_universe, inpacket->options,
DHO_FQDN) != NULL))
priority_list[priority_len++] = DHO_FQDN;
/* Some DHCP Servers will give the subnet-mask option if
* it is not on the parameter request list - so some client
* implementations have come to rely on this - so we will
* also make sure we supply this, at lowest priority.
*
* This is only done in response to DHCPDISCOVER or
* DHCPREQUEST messages, to avoid providing the option on
* DHCPINFORM or DHCPLEASEQUERY responses (if the client
* didn't request it).
*/
if (priority_len < PRIORITY_COUNT)
if ((priority_len < PRIORITY_COUNT) &&
((inpacket->packet_type == DHCPDISCOVER) ||
(inpacket->packet_type == DHCPREQUEST)))
priority_list[priority_len++] = DHO_SUBNET_MASK;
} else {
@ -1104,11 +1114,11 @@ int store_options (ocount, buffer, buflen, packet, lease, client_state,
memset (&od, 0, sizeof od);
/* Eliminate duplicate options in the parameter request list.
There's got to be some clever knuthian way to do this:
Eliminate all but the first occurance of a value in an array
of values without otherwise disturbing the order of the array. */
/* Eliminate duplicate options from the parameter request list.
* Enforce RFC-mandated ordering of options that are present.
*/
for (i = 0; i < priority_len - 1; i++) {
/* Eliminate duplicates. */
tto = 0;
for (ix = i + 1; ix < priority_len + tto; ix++) {
if (tto)
@ -1119,6 +1129,33 @@ int store_options (ocount, buffer, buflen, packet, lease, client_state,
priority_len--;
}
}
/* Enforce ordering of SUBNET_MASK options, according to
* RFC2132 Section 3.3:
*
* If both the subnet mask and the router option are
* specified in a DHCP reply, the subnet mask option MUST
* be first.
*
* This guidance does not specify what to do if the client
* PRL explicitly requests the options out of order, it is
* a general statement.
*/
if (priority_list[i] == DHO_SUBNET_MASK) {
for (ix = i - 1 ; ix >= 0 ; ix--) {
/* We know that anything before 'i' can only
* appear once. So shovel the options to make
* room to bubble the subnet mask ahead, and
* then break out of the loop, we're done.
*/
if (priority_list[ix] == DHO_ROUTERS) {
memmove(priority_list + ix + 1,
priority_list + ix, i - ix);
priority_list[ix] = DHO_SUBNET_MASK;
break;
}
}
}
}
/* Copy out the options in the order that they appear in the