From 2ba8b7cdafcd15b104a1334c58dba2bb98e601b2 Mon Sep 17 00:00:00 2001
From: Ted Lemon <source@isc.org>
Date: Sat, 29 Nov 1997 07:57:02 +0000
Subject: [PATCH] Fix DHCPRELEASE handling to conform to spec

---
 server/dhcp.c | 40 +++++++++++++++++++++++++++++-----------
 1 file changed, 29 insertions(+), 11 deletions(-)

diff --git a/server/dhcp.c b/server/dhcp.c
index 7efd3ddf..4a584ce7 100644
--- a/server/dhcp.c
+++ b/server/dhcp.c
@@ -42,7 +42,7 @@
 
 #ifndef lint
 static char copyright[] =
-"$Id: dhcp.c,v 1.52 1997/10/20 22:28:18 mellon Exp $ Copyright (c) 1995, 1996 The Internet Software Consortium.  All rights reserved.\n";
+"$Id: dhcp.c,v 1.53 1997/11/29 07:57:02 mellon Exp $ Copyright (c) 1995, 1996 The Internet Software Consortium.  All rights reserved.\n";
 #endif /* not lint */
 
 #include "dhcpd.h"
@@ -297,26 +297,44 @@ void dhcprelease (packet)
 {
 	struct lease *lease;
 	struct iaddr cip;
+	int i;
 
-	/* DHCPRELEASEmust specify address. */
-	if (!packet -> options [DHO_DHCP_REQUESTED_ADDRESS].len) {
-		return;
+	/* DHCPRELEASE must not specify address in requested-address
+           option, but old protocol specs weren't explicit about this,
+           so let it go. */
+	if (packet -> options [DHO_DHCP_REQUESTED_ADDRESS].len) {
+		note ("DHCPRELEASE from %s specified requested-address.",
+		      print_hw_addr (packet -> raw -> htype,
+				     packet -> raw -> hlen,
+				     packet -> raw -> chaddr));
 	}
 
-	cip.len = 4;
-	memcpy (cip.iabuf,
-		packet -> options [DHO_DHCP_REQUESTED_ADDRESS].data, 4);
-	lease = find_lease_by_ip_addr (cip);
+	i = DHO_DHCP_CLIENT_IDENTIFIER;
+	if (packet -> options [i].len) {
+		lease = find_lease_by_uid (packet -> options [i].data,
+					   packet -> options [i].len);
+	} else
+		lease = (struct lease *)0;
 
-	note ("DHCPRELEASE of %s from %s via %s",
+	/* The client is supposed to pass a valid client-identifier,
+	   but the spec on this has changed historically, so try the
+	   IP address in ciaddr if the client-identifier fails. */
+	if (!lease) {
+		cip.len = 4;
+		memcpy (cip.iabuf, &packet -> raw -> ciaddr, 4);
+		lease = find_lease_by_ip_addr (cip);
+	}
+
+
+	note ("DHCPRELEASE of %s from %s via %s (%sfound)",
 	      inet_ntoa (packet -> raw -> ciaddr),
 	      print_hw_addr (packet -> raw -> htype,
 			     packet -> raw -> hlen,
 			     packet -> raw -> chaddr),
 	      packet -> raw -> giaddr.s_addr
 	      ? inet_ntoa (packet -> raw -> giaddr)
-	      : packet -> interface -> name);
-
+	      : packet -> interface -> name,
+	      lease ? "" : "not ");
 
 	/* If we found a lease, release it. */
 	if (lease) {