Fix NAKing behaviour for cases where we know about the IP address the

client is asking for and the client can't have it, and also for cases
where we know better than the client what its IP address should be.

diff --git a/server/dhcp.c b/server/dhcp.c
index 1c58cc403e2448fad2c1bf79ac511f974db1348d..f768cb8c40f181d7107829da31abbae15323036f 100644 (file)
--- a/server/dhcp.c
+++ b/server/dhcp.c
@@ -42,7 +42,7 @@
 
 #ifndef lint
 static char copyright[] =
-"$Id: dhcp.c,v 1.57.2.15 1999/02/09 04:57:29 mellon Exp $ Copyright (c) 1995, 1996, 1997, 1998, 1999 The Internet Software Consortium.  All rights reserved.\n";
+"$Id: dhcp.c,v 1.57.2.16 1999/02/16 19:18:35 mellon Exp $ Copyright (c) 1995, 1996, 1997, 1998, 1999 The Internet Software Consortium.  All rights reserved.\n";
 #endif /* not lint */
 
 #include "dhcpd.h"
@@ -1249,6 +1249,19 @@ struct lease *find_lease (packet, share, ours)
        struct lease *fixed_lease;
        int i;
 
+       /* Figure out what IP address the client is requesting, if any. */
+       if (packet -> options [DHO_DHCP_REQUESTED_ADDRESS].len &&
+           packet -> options [DHO_DHCP_REQUESTED_ADDRESS].len == 4) {
+               cip.len = 4;
+               memcpy (cip.iabuf,
+                       packet -> options [DHO_DHCP_REQUESTED_ADDRESS].data,
+                       cip.len);
+       } else if (packet -> raw -> ciaddr.s_addr) {
+               cip.len = 4;
+               memcpy (cip.iabuf, &packet -> raw -> ciaddr, 4);
+       } else
+               cip.len = 0;
+
        /* Try to find a host or lease that's been assigned to the
           specified unique client identifier. */
        if (packet -> options [DHO_DHCP_CLIENT_IDENTIFIER].len) {
@@ -1295,6 +1308,19 @@ struct lease *find_lease (packet, share, ours)
                }
        }
 
+       /* If fixed_lease is present but does not match the requested
+          IP address, and this is a DHCPREQUEST, then we can't return
+          any other lease, so we might as well return now. */
+       if (packet -> packet_type == DHCPREQUEST && fixed_lease &&
+           (fixed_lease -> ip_addr.len != cip.len ||
+            memcmp (fixed_lease -> ip_addr.iabuf,
+                    cip.iabuf, cip.len))) {
+               if (ours)
+                       *ours = 1;
+               strcpy (dhcp_message, "requested address is incorrect");
+               return (struct lease *)0;
+       }
+
        /* Try to find a lease that's been attached to the client's
           hardware address... */
        hw_lease = find_lease_by_hw_addr (packet -> raw -> chaddr,
@@ -1315,18 +1341,9 @@ struct lease *find_lease (packet, share, ours)
 
        /* Try to find a lease that's been allocated to the client's
           IP address. */
-       if (packet -> options [DHO_DHCP_REQUESTED_ADDRESS].len &&
-           packet -> options [DHO_DHCP_REQUESTED_ADDRESS].len == 4) {
-               cip.len = 4;
-               memcpy (cip.iabuf,
-                       packet -> options [DHO_DHCP_REQUESTED_ADDRESS].data,
-                       cip.len);
-               ip_lease = find_lease_by_ip_addr (cip);
-       } else if (packet -> raw -> ciaddr.s_addr) {
-               cip.len = 4;
-               memcpy (cip.iabuf, &packet -> raw -> ciaddr, 4);
+       if (cip.len)
                ip_lease = find_lease_by_ip_addr (cip);
-       } else
+       else
                ip_lease = (struct lease *)0;
 
        /* If ip_lease is valid at this point, set ours to one, so that
@@ -1342,8 +1359,11 @@ struct lease *find_lease (packet, share, ours)
           that thought it had this lease answered an ARP or PING, causing the
           lease to be abandoned.   If so, this request probably came from
           that client. */
-       if (ip_lease && (ip_lease -> shared_network != share))
+       if (ip_lease && (ip_lease -> shared_network != share)) {
+               *ours = 1;
                ip_lease = (struct lease *)0;
+               strcpy (dhcp_message, "requested address on bad subnet");
+       }
 
        /* Toss ip_lease if it hasn't yet expired and the uid doesn't
           match */
@@ -1368,9 +1388,38 @@ struct lease *find_lease (packet, share, ours)
                                      ip_lease -> shared_network -> name);
                        uid_lease = ip_lease;
                }
+               strcpy (dhcp_message, "requested address is not available");
                ip_lease = (struct lease *)0;
+               *ours = 1;
+
+               /* If we get to here and fixed_lease is not null, that means
+                  that there are both a dynamic lease and a fixed-address
+                  declaration for the same IP address. */
+               if (packet -> packet_type == DHCPREQUEST && fixed_lease) {
+                       fixed_lease = (struct lease *)0;
+                     db_conflict:
+                       warn ("Both dynamic and static leases present for %s.",
+                             piaddr (cip));
+                       warn ("Either remove host declaration %s or remove %s",
+                             (fixed_lease && fixed_lease -> host
+                              ? (fixed_lease -> host -> name
+                                 ? fixed_lease -> host -> name : piaddr (cip))
+                              : piaddr (cip)),
+                             piaddr (cip));
+                       warn ("from the dynamic address pool for %s",
+                             ip_lease -> subnet -> shared_network -> name);
+                       if (fixed_lease)
+                               ip_lease = (struct lease *)0;
+                       strcpy (dhcp_message,
+                               "database conflict - call for help!");
+               }
        }
 
+       /* If we get to here with both fixed_lease and ip_lease not
+          null, then we have a configuration file bug. */
+       if (packet -> packet_type == DHCPREQUEST && fixed_lease && ip_lease)
+               goto db_conflict;
+
        /* Toss hw_lease if it hasn't yet expired and the uid doesn't
           match, except that if the hardware address matches and the
           client is now doing dynamic BOOTP (and thus hasn't provided
@@ -1383,29 +1432,18 @@ struct lease *find_lease (packet, share, ours)
                hw_lease = (struct lease *)0;
 
        /* Toss extra pointers to the same lease... */
-       if (ip_lease == hw_lease)
-               ip_lease = (struct lease *)0;
        if (hw_lease == uid_lease)
                hw_lease = (struct lease *)0;
+       if (ip_lease == hw_lease)
+               hw_lease = (struct lease *)0;
        if (ip_lease == uid_lease)
-               ip_lease = (struct lease *)0;
-
-       /* If we got an ip address lease, make sure it isn't assigned to
-          some *other* client!   If it was assigned to this client, we'd
-          have zeroed it out above, so the only way we can take it at this
-          point is if some other client had it but it's timed out, or if no
-          other client has ever had it. */
-       if (ip_lease &&
-           ip_lease -> ends >= cur_time)
-               ip_lease = (struct lease *)0;
+               uid_lease = (struct lease *)0;
 
        /* If we've already eliminated the lease, it wasn't there to
           begin with.   If we have come up with a matching lease,
           set the message to bad network in case we have to throw it out. */
-       if (!ip_lease && !hw_lease && !uid_lease) {
+       if (!ip_lease) {
                strcpy (dhcp_message, "requested address not available");
-       } else {
-               strcpy (dhcp_message, "requested address on bad subnet");
        }
 
        /* Now eliminate leases that are on the wrong network... */
@@ -1425,6 +1463,12 @@ struct lease *find_lease (packet, share, ours)
                hw_lease = (struct lease *)0;
        }
 
+       /* If this is a DHCPREQUEST, make sure the lease we're going to return
+          matches the requested IP address.   If it doesn't, don't return a
+          lease at all. */
+       if (packet -> packet_type == DHCPREQUEST && !ip_lease && !fixed_lease)
+               return (struct lease *)0;
+
        /* At this point, if fixed_lease is nonzero, we can assign it to
           this client. */
        if (fixed_lease) {