Intermediate changes to support actual DHCP protocol engine

29 files changed, 972 insertions, 120 deletions

diff --git a/Makefile b/Makefile
index e745f08e..c90b3043 100644
--- a/Makefile
+++ b/Makefile
@@ -11,6 +11,8 @@ CFLAGS += -DDEBUG -g -Wall -Wstrict-prototypes -Wno-unused \
 	  -Wno-uninitialized -Werror
 
 dhclient:	dhclient.o confpars.o alloc.o memory.o options.o \
-		hash.o tables.o inet.o convert.o conflex.o errwarn.o tree.o
+		hash.o tables.o inet.o convert.o conflex.o errwarn.o \
+		tree.o print.o
 	cc -o dhclient dhclient.o confpars.o alloc.o memory.o options.o \
-		hash.o tables.o inet.o convert.o conflex.o errwarn.o tree.o
\ No newline at end of file
+		hash.o tables.o inet.o convert.o conflex.o errwarn.o \
+		print.o tree.o
\ No newline at end of file
diff --git a/client/dhclient.c b/client/dhclient.c
index 0a66c41d..c9d9e64d 100644
--- a/client/dhclient.c
+++ b/client/dhclient.c
@@ -189,11 +189,51 @@ int main (argc, argv, envp)
 
 			cons_options ((struct packet *)0,
 				      &outgoing, &decl, bufs);
-			memset (&raw.ciaddr, 0, sizeof raw.ciaddr);
-			memset (&raw.yiaddr, 0, sizeof raw.ciaddr);
-			memset (&raw.siaddr, 0, sizeof raw.ciaddr);
-			memset (&raw.giaddr, 0, sizeof raw.ciaddr);
-			
+
+			if (decl.ciaddr) {
+				if (tree_evaluate (decl.ciaddr) != 4)
+					warn ("ciaddr is more"
+					      " than one address");
+				else
+					memcpy (&raw.ciaddr,
+						decl.ciaddr -> value,
+						decl.ciaddr -> len);
+			} else
+				memset (&raw.ciaddr, 0, sizeof raw.ciaddr);
+
+			if (decl.yiaddr) {
+				if (tree_evaluate (decl.yiaddr) != 4)
+					warn ("yiaddr is more"
+					      " than one address");
+				else
+					memcpy (&raw.yiaddr,
+						decl.yiaddr -> value,
+						decl.yiaddr -> len);
+			} else
+				memset (&raw.yiaddr, 0, sizeof raw.yiaddr);
+
+			if (decl.siaddr) {
+				if (tree_evaluate (decl.siaddr) != 4)
+					warn ("siaddr is more"
+					      " than one address");
+				else
+					memcpy (&raw.siaddr,
+						decl.siaddr -> value,
+						decl.siaddr -> len);
+			} else
+				memset (&raw.siaddr, 0, sizeof raw.siaddr);
+
+			if (decl.giaddr) {
+				if (tree_evaluate (decl.giaddr) != 4)
+					warn ("giaddr is more"
+					      " than one address");
+				else
+					memcpy (&raw.giaddr,
+						decl.giaddr -> value,
+						decl.giaddr -> len);
+			} else
+				memset (&raw.giaddr, 0, sizeof raw.giaddr);
+
 			raw.xid = xid++;
 			raw.xid = htons (raw.xid);
 			raw.secs = 0;
diff --git a/common/conflex.c b/common/conflex.c
index 33e58318..28a9f65e 100644
--- a/common/conflex.c
+++ b/common/conflex.c
@@ -274,6 +274,8 @@ static int intern (atom, dfv)
 	      case 'c':
 		if (!strcasecmp (atom + 1, "lass"))
 			return CLASS;
+		if (!strcasecmp (atom + 1, "iaddr"))
+			return CIADDR;
 		break;
 	      case 'e':
 		if (!strcasecmp (atom + 1, "thernet"))
@@ -287,6 +289,10 @@ static int intern (atom, dfv)
 		if (!strcasecmp (atom + 1, "ixed-address"))
 			return FIXED_ADDR;
 		break;
+	      case 'g':
+		if (!strcasecmp (atom + 1, "iaddr"))
+			return GIADDR;
+		break;
 	      case 'h':
 		if (!strcasecmp (atom + 1, "ost"))
 			return HOST;
@@ -312,6 +318,8 @@ static int intern (atom, dfv)
 	      case 's':
 		if (!strcasecmp (atom + 1, "tarts"))
 			return STARTS;
+		if (!strcasecmp (atom + 1, "iaddr"))
+			return SIADDR;
 		break;
 	      case 't':
 		if (!strcasecmp (atom + 1, "timestamp"))
@@ -321,6 +329,10 @@ static int intern (atom, dfv)
 		if (!strcasecmp (atom + 1, "id"))
 			return UID;
 		break;
+	      case 'y':
+		if (!strcasecmp (atom + 1, "iaddr"))
+			return YIADDR;
+		break;
 	}
 	return dfv;
 }
diff --git a/common/hash.c b/common/hash.c
index 8bc724e7..cf15ba31 100644
--- a/common/hash.c
+++ b/common/hash.c
@@ -103,6 +103,7 @@ void add_hash (table, name, len, pointer)
 	bp -> name = name;
 	bp -> value = pointer;
 	bp -> next = table -> buckets [hashno];
+	bp -> len = len;
 	table -> buckets [hashno] = bp;
 }
 
@@ -140,10 +141,11 @@ unsigned char *hash_lookup (table, name, len)
 	struct hash_bucket *bp;
 
 	if (len) {
-		for (bp = table -> buckets [hashno]; bp; bp = bp -> next)
+		for (bp = table -> buckets [hashno]; bp; bp = bp -> next) {
 			if (len == bp -> len
 			    && !memcmp (bp -> name, name, len))
 				return bp -> value;
+		}
 	} else {
 		for (bp = table -> buckets [hashno]; bp; bp = bp -> next)
 			if (!strcmp (bp -> name, name))
diff --git a/common/inet.c b/common/inet.c
index fa25efc1..ce63a2b4 100644
--- a/common/inet.c
+++ b/common/inet.c
@@ -87,7 +87,7 @@ struct iaddr ip_addr (subnet, mask, host_address)
 	j = rv.len - sizeof habuf;
 	for (i = sizeof habuf - 1; i >= 0; i--) {
 		if (mask.iabuf [i + j]) {
-			if (habuf [i] > ~mask.iabuf [i + j]) {
+			if (habuf [i] > (mask.iabuf [i + j] ^ 0xFF)) {
 				rv.len = 0;
 				return rv;
 			}
@@ -97,10 +97,10 @@ struct iaddr ip_addr (subnet, mask, host_address)
 					return rv;
 				}
 			}
-			rv.iabuf [i + j] &= habuf [i];
+			rv.iabuf [i + j] |= habuf [i];
 			break;
-		}
-		rv.iabuf [i + j] = habuf [i];
+		} else
+			rv.iabuf [i + j] = habuf [i];
 	}
 		
 	return rv;
diff --git a/common/memory.c b/common/memory.c
index 21b1c010..13bf3492 100644
--- a/common/memory.c
+++ b/common/memory.c
@@ -48,7 +48,7 @@ static char copyright[] =
 #include "dhcpd.h"
 
 static struct host_decl *hosts;
-static struct hash_table *subnet_hash;
+static struct subnet *subnets;
 static struct hash_table *lease_uid_hash;
 static struct hash_table *lease_ip_addr_hash;
 static struct hash_table *lease_hw_addr_hash;
@@ -98,12 +98,10 @@ void new_address_range (low, high, netmask)
 	struct lease *address_range, *lp, *plp;
 	struct subnet *subnet;
 	struct iaddr net;
-	int i, max;
+	int min, max, i;
 	char lowbuf [16], highbuf [16], netbuf [16];
 
 	/* Initialize the hash table if it hasn't been done yet. */
-	if (!subnet_hash)
-		subnet_hash = new_hash ();
 	if (!lease_uid_hash)
 		lease_uid_hash = new_hash ();
 	if (!lease_ip_addr_hash)
@@ -130,32 +128,40 @@ void new_address_range (low, high, netmask)
 		subnet -> net = net;
 		subnet -> netmask = netmask;
 		subnet -> leases = (struct lease *)0;
+		subnet -> last_lease = (struct lease *)0;
+		subnet -> next = (struct subnet *)0;
+		subnet -> default_lease_time = default_lease_time;
+		subnet -> max_lease_time = max_lease_time;
 		enter_subnet (subnet);
 	}
 
 	/* Get the high and low host addresses... */
 	max = host_addr (high, netmask);
-	i = host_addr (low, netmask);
+	min = host_addr (low, netmask);
 
 	/* Allow range to be specified high-to-low as well as low-to-high. */
-	if (i > max) {
-		max = i;
-		i = host_addr (high, netmask);
+	if (min > max) {
+		max = min;
+		min = host_addr (high, netmask);
 	}
 
 	/* Get a lease structure for each address in the range. */
-	address_range = new_leases (max - i + 1, "new_address_range");
+	address_range = new_leases (max - min + 1, "new_address_range");
 	if (!address_range) {
 		strcpy (lowbuf, piaddr (low));
 		strcpy (highbuf, piaddr (high));
 		error ("No memory for address range %s-%s.", lowbuf, highbuf);
 	}
-	memset (address_range, 0, (sizeof *address_range) * (max - i + 1));
+	memset (address_range, 0, (sizeof *address_range) * (max - min + 1));
+
+	/* Fill in the last lease if it hasn't been already... */
+	if (!subnet -> last_lease)
+		subnet -> last_lease = &address_range [0];
 
 	/* Fill out the lease structures with some minimal information. */
-	for (; i <= max; i++) {
+	for (i = 0; i < max - min + 1; i++) {
 		address_range [i].ip_addr =
-			ip_addr (subnet -> net, subnet -> netmask, i);
+			ip_addr (subnet -> net, subnet -> netmask, i + min);
 		address_range [i].starts =
 			address_range [i].timestamp = MIN_TIME;
 		address_range [i].ends = MIN_TIME;
@@ -200,13 +206,16 @@ void new_address_range (low, high, netmask)
 	}
 }
 
-struct subnet *find_subnet (subnet)
-	struct iaddr subnet;
+struct subnet *find_subnet (addr)
+	struct iaddr addr;
 {
 	struct subnet *rv;
 
-	return (struct subnet *)hash_lookup (subnet_hash,
-					     (char *)subnet.iabuf, subnet.len);
+	for (rv = subnets; rv; rv = rv -> next) {
+		if (addr_eq (subnet_number (addr, rv -> netmask), rv -> net))
+			return rv;
+	}
+	return (struct subnet *)0;
 }
 
 /* Enter a new subnet into the subnet hash. */
@@ -214,8 +223,9 @@ struct subnet *find_subnet (subnet)
 void enter_subnet (subnet)
 	struct subnet *subnet;
 {
-	add_hash (subnet_hash, (char *)subnet -> net.iabuf,
-		  subnet -> net.len, (unsigned char *)subnet);
+	/* XXX Sort the nets into a balanced tree to make searching quicker. */
+	subnet -> next = subnets;
+	subnets = subnet;
 }
 	
 /* Enter a lease into the system.   This is called by the parser each
@@ -259,6 +269,11 @@ void supersede_lease (comp, lease)
 	struct subnet *parent;
 	struct lease *lp;
 
+printf ("Supersede_lease:\n");
+print_lease (comp);
+print_lease (lease);
+printf ("\n");
+
 	/* If the existing lease hasn't expired and has a different
 	   unique identifier or, if it doesn't have a unique
 	   identifier, a different hardware address, then the two
@@ -290,7 +305,9 @@ void supersede_lease (comp, lease)
 				enter_uid = 1;
 			}
 			free (comp -> uid);
-		}
+		} else
+			enter_uid = 1;
+
 		if (comp -> hardware_addr.htype &&
 		    ((comp -> hardware_addr.hlen !=
 		      lease -> hardware_addr.hlen) ||
@@ -303,7 +320,8 @@ void supersede_lease (comp, lease)
 					   comp -> hardware_addr.haddr,
 					   comp -> hardware_addr.hlen);
 			enter_hwaddr = 1;
-		}
+		} else if (!comp -> hardware_addr.htype)
+			enter_hwaddr = 1;
 
 		/* Copy the data files, but not the linkages. */
 		comp -> starts = lease -> starts;
@@ -317,16 +335,16 @@ void supersede_lease (comp, lease)
 
 		/* Record the lease in the uid hash if necessary. */
 		if (enter_uid && lease -> uid) {
-			add_hash (lease_uid_hash, lease -> uid,
-				  lease -> uid_len, (unsigned char *)lease);
+			add_hash (lease_uid_hash, comp -> uid,
+				  comp -> uid_len, (unsigned char *)comp);
 		}
 
 		/* Record it in the hardware address hash if necessary. */
 		if (enter_hwaddr && lease -> hardware_addr.htype) {
 			add_hash (lease_hw_addr_hash,
-				  lease -> hardware_addr.haddr,
-				  lease -> hardware_addr.hlen,
-				  (unsigned char *)lease);
+				  comp -> hardware_addr.haddr,
+				  comp -> hardware_addr.hlen,
+				  (unsigned char *)comp);
 		}
 
 		/* Remove the lease from its current place in the list. */
@@ -338,6 +356,9 @@ void supersede_lease (comp, lease)
 		if (comp -> next) {
 			comp -> next -> prev = comp -> prev;
 		}
+		if (comp -> contain -> last_lease == comp) {
+			comp -> contain -> last_lease = comp -> prev;
+		}
 
 		/* Find the last insertion point... */
 		if (comp == comp -> contain -> insertion_point ||
@@ -351,18 +372,20 @@ void supersede_lease (comp, lease)
 			/* Nothing on the list yet?    Just make comp the
 			   head of the list. */
 			comp -> contain -> leases = comp;
-		} else if (lp -> ends <= comp -> ends) {
+			comp -> contain -> last_lease = comp;
+		} else if (lp -> ends > comp -> ends) {
 			/* Skip down the list until we run out of list
 			   or find a place for comp. */
-			while (lp -> next && lp -> ends < comp -> ends) {
+			while (lp -> next && lp -> ends > comp -> ends) {
 				lp = lp -> next;
 			}
-			if (lp -> ends < comp -> ends) {
+			if (lp -> ends > comp -> ends) {
 				/* If we ran out of list, put comp
 				   at the end. */
 				lp -> next = comp;
 				comp -> prev = lp;
 				comp -> next = (struct lease *)0;
+				comp -> contain -> last_lease = comp;
 			} else {
 				/* If we didn't, put it between lp and
 				   the previous item on the list. */
@@ -372,12 +395,12 @@ void supersede_lease (comp, lease)
 				lp -> prev = comp;
 			}
 		} else {
-			/* Skip ip the list until we run out of list
+			/* Skip up the list until we run out of list
 			   or find a place for comp. */
-			while (lp -> prev && lp -> ends > comp -> ends) {
+			while (lp -> prev && lp -> ends < comp -> ends) {
 				lp = lp -> prev;
 			}
-			if (lp -> ends > comp -> ends) {
+			if (lp -> ends < comp -> ends) {
 				/* If we ran out of list, put comp
 				   at the beginning. */
 				lp -> prev = comp;
@@ -397,6 +420,18 @@ void supersede_lease (comp, lease)
 	}
 }
 
+/* Release the specified lease and re-hash it as appropriate. */
+
+void release_lease (lease)
+	struct lease *lease;
+{
+	struct lease lt;
+
+	lease -> ends = 0;
+	lt = *lease;
+	supersede_lease (lease, &lt);
+}
+
 /* Locate the lease associated with a given IP address... */
 
 struct lease *find_lease_by_ip_addr (addr)
@@ -417,3 +452,29 @@ struct lease *find_lease_by_uid (uid, len)
 	return lease;
 }
 
+struct lease *find_lease_by_hw_addr (hwaddr, hwlen)
+	unsigned char *hwaddr;
+	int hwlen;
+{
+	struct lease *lease = (struct lease *)hash_lookup (lease_hw_addr_hash,
+							   hwaddr, hwlen);
+	return lease;
+}
+
+void dump_subnets ()
+{
+	struct lease *l;
+	struct subnet *s;
+	int i;
+
+	for (s = subnets; s; s = s -> next) {
+		printf ("Subnet %s", piaddr (s -> net));
+		printf (" netmask %s\n",
+			piaddr (s -> netmask));
+		for (l = s -> leases; l; l = l -> next) {
+			print_lease (l);
+		}
+		printf ("Last Lease:\n");
+		print_lease (s -> last_lease);
+	}
+}
diff --git a/common/options.c b/common/options.c
index 75bfc5e5..f9fa44d3 100644
--- a/common/options.c
+++ b/common/options.c
@@ -94,8 +94,6 @@ void parse_option_buffer (packet, buffer, length)
 	int len;
 	int code;
 
-printf ("parse_option_buffer (%x, %x, %d)\n",
-(unsigned long)packet, (unsigned long)buffer, length);
 	for (s = buffer; *s != DHO_END && s < end; ) {
 		code = s [0];
 		/* Pad options don't have a length - just skip them. */
@@ -126,8 +124,6 @@ printf ("parse_option_buffer (%x, %x, %d)\n",
 			t [len] = 0;
 			packet -> options [code].len = len;
 			packet -> options [code].data = t;
-printf ("%s=%s\n", dhcp_options [code].name,
-pretty_print_option (code, t, len));
 		} else {
 			/* If it's a repeat, concatenate it to whatever
 			   we last saw.   This is really only required
diff --git a/common/print.c b/common/print.c
index 55d17159..4686e2e3 100644
--- a/common/print.c
+++ b/common/print.c
@@ -55,13 +55,46 @@ char *print_hw_addr (htype, hlen, data)
 	char *s;
 	int i;
 
-	s = habuf;
-	for (i = 0; i < hlen; i++) {
-		sprintf (s, "%x", data [i]);
-		s += strlen (s);
-		*s++ = ':';
+	if (htype == 0 || hlen == 0) {
+		strcpy (habuf, "<null>");
+	} else {
+		s = habuf;
+		for (i = 0; i < hlen; i++) {
+			sprintf (s, "%x", data [i]);
+			s += strlen (s);
+			*s++ = ':';
+		}
+		*--s = 0;
 	}
-	*--s = 0;
 	return habuf;
 }
 
+void print_lease (lease)
+	struct lease *lease;
+{
+	struct tm *t;
+	char tbuf [32];
+
+	printf ("  Lease %s",
+		piaddr (lease -> ip_addr));
+	
+	t = gmtime (&lease -> starts);
+	strftime (tbuf, sizeof tbuf, "%D %H:%M:%S", t);
+	printf ("  start %s", tbuf);
+	
+	t = gmtime (&lease -> ends);
+	strftime (tbuf, sizeof tbuf, "%D %H:%M:%S", t);
+	printf ("  end %s", tbuf);
+	
+	t = gmtime (&lease -> timestamp);
+	strftime (tbuf, sizeof tbuf, "%D %H:%M:%S", t);
+	printf ("  stamp %s\n", tbuf);
+	
+	printf ("    hardware addr = %s",
+		print_hw_addr (lease -> hardware_addr.htype,
+			       lease -> hardware_addr.hlen,
+			       lease -> hardware_addr.haddr));
+	printf ("  host %s  state %x\n",
+		lease -> host ? lease -> host -> name : "<none>",
+		lease -> state);
+}	
diff --git a/common/socket.c b/common/socket.c
index 3a013cf0..c69e68cc 100644
--- a/common/socket.c
+++ b/common/socket.c
@@ -184,6 +184,9 @@ void dispatch ()
 		/* Wait for a packet or a timeout... XXX */
 		count = select (max + 1, &r, &w, &x, (struct timeval *)0);
 
+		/* Get the current time... */
+		GET_TIME (&cur_time);
+
 		/* Not likely to be transitory... */
 		if (count < 0)
 			error ("select: %m");
diff --git a/conflex.c b/conflex.c
index 33e58318..28a9f65e 100644
--- a/conflex.c
+++ b/conflex.c
@@ -274,6 +274,8 @@ static int intern (atom, dfv)
 	      case 'c':
 		if (!strcasecmp (atom + 1, "lass"))
 			return CLASS;
+		if (!strcasecmp (atom + 1, "iaddr"))
+			return CIADDR;
 		break;
 	      case 'e':
 		if (!strcasecmp (atom + 1, "thernet"))
@@ -287,6 +289,10 @@ static int intern (atom, dfv)
 		if (!strcasecmp (atom + 1, "ixed-address"))
 			return FIXED_ADDR;
 		break;
+	      case 'g':
+		if (!strcasecmp (atom + 1, "iaddr"))
+			return GIADDR;
+		break;
 	      case 'h':
 		if (!strcasecmp (atom + 1, "ost"))
 			return HOST;
@@ -312,6 +318,8 @@ static int intern (atom, dfv)
 	      case 's':
 		if (!strcasecmp (atom + 1, "tarts"))
 			return STARTS;
+		if (!strcasecmp (atom + 1, "iaddr"))
+			return SIADDR;
 		break;
 	      case 't':
 		if (!strcasecmp (atom + 1, "timestamp"))
@@ -321,6 +329,10 @@ static int intern (atom, dfv)
 		if (!strcasecmp (atom + 1, "id"))
 			return UID;
 		break;
+	      case 'y':
+		if (!strcasecmp (atom + 1, "iaddr"))
+			return YIADDR;
+		break;
 	}
 	return dfv;
 }
diff --git a/confpars.c b/confpars.c
index 7335de6f..1be52bb9 100644
--- a/confpars.c
+++ b/confpars.c
@@ -234,6 +234,22 @@ void parse_host_decl (cfile, bc, decl)
 	      case OPTION:
 		parse_option_decl (cfile, bc, decl);
 		break;
+	      case CIADDR:
+		decl -> ciaddr =
+			tree_cache (parse_ip_addr_or_hostname (cfile, bc, 0));
+		break;
+	      case YIADDR:
+		decl -> yiaddr =
+			tree_cache (parse_ip_addr_or_hostname (cfile, bc, 0));
+		break;
+	      case SIADDR:
+		decl -> siaddr =
+			tree_cache (parse_ip_addr_or_hostname (cfile, bc, 0));
+		break;
+	      case GIADDR:
+		decl -> giaddr =
+			tree_cache (parse_ip_addr_or_hostname (cfile, bc, 0));
+		break;
 	      default:
 		parse_warn ("expecting a dhcp option declaration.");
 		skip_to_semi (cfile);
diff --git a/dhclient.c b/dhclient.c
index 0a66c41d..c9d9e64d 100644
--- a/dhclient.c
+++ b/dhclient.c
@@ -189,11 +189,51 @@ int main (argc, argv, envp)
 
 			cons_options ((struct packet *)0,
 				      &outgoing, &decl, bufs);
-			memset (&raw.ciaddr, 0, sizeof raw.ciaddr);
-			memset (&raw.yiaddr, 0, sizeof raw.ciaddr);
-			memset (&raw.siaddr, 0, sizeof raw.ciaddr);
-			memset (&raw.giaddr, 0, sizeof raw.ciaddr);
-			
+
+			if (decl.ciaddr) {
+				if (tree_evaluate (decl.ciaddr) != 4)
+					warn ("ciaddr is more"
+					      " than one address");
+				else
+					memcpy (&raw.ciaddr,
+						decl.ciaddr -> value,
+						decl.ciaddr -> len);
+			} else
+				memset (&raw.ciaddr, 0, sizeof raw.ciaddr);
+
+			if (decl.yiaddr) {
+				if (tree_evaluate (decl.yiaddr) != 4)
+					warn ("yiaddr is more"
+					      " than one address");
+				else
+					memcpy (&raw.yiaddr,
+						decl.yiaddr -> value,
+						decl.yiaddr -> len);
+			} else
+				memset (&raw.yiaddr, 0, sizeof raw.yiaddr);
+
+			if (decl.siaddr) {
+				if (tree_evaluate (decl.siaddr) != 4)
+					warn ("siaddr is more"
+					      " than one address");
+				else
+					memcpy (&raw.siaddr,
+						decl.siaddr -> value,
+						decl.siaddr -> len);
+			} else
+				memset (&raw.siaddr, 0, sizeof raw.siaddr);
+
+			if (decl.giaddr) {
+				if (tree_evaluate (decl.giaddr) != 4)
+					warn ("giaddr is more"
+					      " than one address");
+				else
+					memcpy (&raw.giaddr,
+						decl.giaddr -> value,
+						decl.giaddr -> len);
+			} else
+				memset (&raw.giaddr, 0, sizeof raw.giaddr);
+
 			raw.xid = xid++;
 			raw.xid = htons (raw.xid);
 			raw.secs = 0;
diff --git a/dhcp.c b/dhcp.c
index fa49eccc..640c726f 100644
--- a/dhcp.c
+++ b/dhcp.c
@@ -49,5 +49,205 @@ static char copyright[] =
 void dhcp (packet)
 	struct packet *packet;
 {
+	struct lease *uid_lease, *ip_lease, *hw_lease, *lease;
+	struct iaddr cip;
+	struct lease lt;
+	TIME lease_time;
+
 	dump_packet (packet);
+
+	/* Try to find a lease that's been assigned to the specified
+	   unique client identifier. */
+	if (packet -> options [DHO_DHCP_CLIENT_IDENTIFIER].len)
+		uid_lease =
+			find_lease_by_uid (packet -> options
+					   [DHO_DHCP_CLIENT_IDENTIFIER].data,
+					   packet -> options
+					   [DHO_DHCP_CLIENT_IDENTIFIER].len);
+	else
+		uid_lease = (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,
+					  packet -> raw -> hlen);
+
+	/* 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
+	    <= sizeof cip.iabuf) {
+		cip.len = packet -> options [DHO_DHCP_REQUESTED_ADDRESS].len;
+		memcpy (cip.iabuf,
+			packet -> options [DHO_DHCP_REQUESTED_ADDRESS].data,
+			packet -> options [DHO_DHCP_REQUESTED_ADDRESS].len);
+		memcpy (cip.iabuf, &packet -> raw -> ciaddr, 4);
+		ip_lease = find_lease_by_ip_addr (cip);
+	} else
+		ip_lease = (struct lease *)0;
+
+	printf ("First blush:\n");
+	if (ip_lease) {
+		printf ("ip_lease: ");
+		print_lease (ip_lease);
+	}
+	if (hw_lease) {
+		printf ("hw_lease: ");
+		print_lease (hw_lease);
+	}
+	if (uid_lease) {
+		printf ("uid_lease: ");
+		print_lease (uid_lease);
+	}
+
+	/* 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 == uid_lease)
+		ip_lease = (struct lease *)0;
+
+	printf ("Second blush:\n");
+	if (ip_lease) {
+		printf ("ip_lease: ");
+		print_lease (ip_lease);
+	}
+	if (hw_lease) {
+		printf ("hw_lease: ");
+		print_lease (hw_lease);
+	}
+	if (uid_lease) {
+		printf ("uid_lease: ");
+		print_lease (uid_lease);
+	}
+
+	/* 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;
+
+	/* Now eliminate leases that are on the wrong subnet... */
+	if (ip_lease && packet -> subnet != ip_lease -> contain) {
+		release_lease (ip_lease);
+		ip_lease = (struct lease *)0;
+	}
+	if (uid_lease && packet -> subnet != uid_lease -> contain) {
+		release_lease (uid_lease);
+		uid_lease = (struct lease *)0;
+	}
+	if (hw_lease && packet -> subnet != hw_lease -> contain) {
+		release_lease (hw_lease);
+		hw_lease = (struct lease *)0;
+	}
+
+	printf ("Third blush:\n");
+	if (ip_lease) {
+		printf ("ip_lease: ");
+		print_lease (ip_lease);
+	}
+	if (hw_lease) {
+		printf ("hw_lease: ");
+		print_lease (hw_lease);
+	}
+	if (uid_lease) {
+		printf ("uid_lease: ");
+		print_lease (uid_lease);
+	}
+
+	/* At this point, if ip_lease is nonzero, we can assign it to
+	   this client. */
+	lease = ip_lease;
+
+	/* If we got a lease that matched the client identifier, we may want
+	   to use it, but if we already have a lease we like, we must free
+	   the lease that matched the client identifier. */
+	if (uid_lease) {
+		if (lease) {
+			release_lease (uid_lease);
+		} else
+			lease = uid_lease;
+	}
+
+	/* The lease that matched the hardware address is treated likewise. */
+	if (hw_lease) {
+		if (lease) {
+			release_lease (hw_lease);
+		} else
+			lease = hw_lease;
+	}
+
+	/* If we didn't find a lease, try to allocate one... */
+	if (!lease) {
+		lease = packet -> subnet -> last_lease;
+
+		/* If there are no leases in that subnet that have
+		   expired, we have nothing to offer this client. */
+		if (lease -> ends >= cur_time) {
+			note ("no free leases on subnet %s",
+			      piaddr (packet -> subnet -> net));
+			return;
+		}
+		lease -> host = (struct host_decl *)0;
+	}
+
+	/* At this point, we have a lease that we can offer the client.
+	   Now we construct a lease structure that contains what we want,
+	   and call supersede_lease to do the right thing with it. */
+
+	memset (&lt, 0, sizeof lt);
+
+	/* Use the ip address of the lease that we finally found in
+	   the database. */
+	lt.ip_addr = lease -> ip_addr;
+
+	/* Start now. */
+	lt.starts = cur_time;
+
+	/* Figure out how long a lease to assign. */
+	if (packet -> options [DHO_DHCP_LEASE_TIME].len == 4) {
+		lease_time = getULong (packet ->
+				       options [DHO_DHCP_LEASE_TIME].data);
+
+		/* Don't let the client ask for a longer lease than
+		   is supported for this subnet. */
+		if (lease_time > packet -> subnet -> max_lease_time)
+			lease_time = packet -> subnet -> max_lease_time;
+	} else
+		lease_time = packet -> subnet -> default_lease_time;
+	lt.ends = cur_time + lease_time;
+
+	lt.timestamp = cur_time;
+
+	/* Record the uid, if given... */
+	if (packet -> options [DHO_DHCP_CLIENT_IDENTIFIER].len) {
+		lt.uid_len =
+			packet -> options [DHO_DHCP_CLIENT_IDENTIFIER].len;
+		lt.uid = packet -> options [DHO_DHCP_CLIENT_IDENTIFIER].data;
+		packet -> options [DHO_DHCP_CLIENT_IDENTIFIER].data =
+			(unsigned char *)0;
+		packet -> options [DHO_DHCP_CLIENT_IDENTIFIER].len = 0;
+	}
+
+	/* Record the hardware address, if given... */
+	lt.hardware_addr.hlen = packet -> raw -> hlen;
+	lt.hardware_addr.htype = packet -> raw -> htype;
+	memcpy (lt.hardware_addr.haddr, packet -> raw -> chaddr,
+		packet -> raw -> hlen);
+
+	lt.host = lease -> host; /* XXX */
+	lt.contain = lease -> contain;
+
+	/* Record the transaction id... */
+	lt.xid = packet -> raw -> xid;
+
+	/* Install the new information about this lease in the database. */
+	supersede_lease (lease, &lt);
+
+	/* Send a response to the client... */
+	dump_subnets ();
 }
diff --git a/dhcpd.c b/dhcpd.c
index b9e527c8..159d3b85 100644
--- a/dhcpd.c
+++ b/dhcpd.c
@@ -50,7 +50,10 @@ static char copyright[] =
 static void usage PROTO ((void));
 
 TIME cur_time;
+TIME default_lease_time = 43200; /* 12 hours... */
+TIME max_lease_time = 86400; /* 24 hours... */
 
+struct subnet *local_subnet;
 u_int32_t *server_addrlist;
 int server_addrcount;
 u_int16_t server_port;
@@ -63,6 +66,7 @@ int main (argc, argv, envp)
 	int port = 0;
 	int i;
 	struct sockaddr_in name;
+	struct iaddr taddr;
 	u_int32_t *addrlist = (u_int32_t *)0;
 	int addrcount = 0;
 	struct tree *addrtree = (struct tree *)0;
@@ -148,7 +152,23 @@ int main (argc, argv, envp)
 	}
 #endif
 
+	taddr.len = 0;
 	server_addrlist = get_interface_list (&server_addrcount);
+	for (i = 0; i < server_addrcount; i++) {
+		struct sockaddr_in foo;
+		foo.sin_addr.s_addr = server_addrlist [i];
+		printf ("Address %d: %s\n", i, inet_ntoa (foo.sin_addr));
+
+		if (server_addrlist [i] != htonl (INADDR_LOOPBACK)) {
+			if (taddr.len) {
+				error ("dhcpd currently does not support "
+				       "multiple interfaces");
+			}
+			taddr.len = 4;
+			memcpy (taddr.iabuf, &server_addrlist [i], 4);
+			local_subnet = find_subnet (taddr);
+		}
+	}
 
 	/* Listen on the specified (or default) port on each specified
 	   (or default) IP address. */
@@ -164,6 +184,8 @@ int main (argc, argv, envp)
 		close (i);
 	}
 
+	dump_subnets ();
+
 	/* Receive packets and dispatch them... */
 	dispatch ();
 
@@ -191,6 +213,7 @@ void do_packet (packbuf, len, from_port, from, sock)
 {
 	struct packet *tp;
 	struct dhcp_packet *tdp;
+	struct iaddr ia;
 
 	if (!(tp = new_packet ("do_packet")))
 		return;
@@ -205,12 +228,29 @@ void do_packet (packbuf, len, from_port, from, sock)
 	tp -> client_port = from_port;
 	tp -> client_addr = from;
 	tp -> client_sock = sock;
-	parse_options (tp);
-	if (tp -> options_valid &&
-	    tp -> options [DHO_DHCP_MESSAGE_TYPE].data)
-		dhcp (tp);
-	else
-		bootp (tp);
+	
+	/* If this came through a gateway, find the corresponding subnet... */
+	if (tp -> raw -> giaddr.s_addr) {
+		ia.len = 4;
+		memcpy (ia.iabuf, &tp -> raw -> giaddr, 4);
+		tp -> subnet = find_subnet (ia);
+	} else {
+		tp -> subnet = local_subnet;
+	}
+
+	/* If the subnet from whence this packet came is unknown to us,
+	   drop it on the floor... */
+	if (!tp -> subnet)
+		note ("Packet from unknown subnet: %s",
+		      inet_ntoa (tp -> raw -> giaddr));
+	else {
+		parse_options (tp);
+		if (tp -> options_valid &&
+		    tp -> options [DHO_DHCP_MESSAGE_TYPE].data)
+			dhcp (tp);
+		else
+			bootp (tp);
+	}
 }
 
 void dump_packet (tp)
diff --git a/dhcpd.conf b/dhcpd.conf
index 10d66a37..bc8a1d77 100644
--- a/dhcpd.conf
+++ b/dhcpd.conf
@@ -1,4 +1,5 @@
-range 204.254.239.11 204.254.239.254 255.255.255.0;
+range 204.254.239.11 204.254.239.17 255.255.255.0;
+range 204.254.240.11 204.254.240.12 255.255.255.0;
 
 host minuet
 	hardware ethernet 08:00:2b:35:0c:18
diff --git a/dhcpd.h b/dhcpd.h
index 655b57eb..81d5cccc 100644
--- a/dhcpd.h
+++ b/dhcpd.h
@@ -53,6 +53,7 @@
 #include <stdlib.h>
 #include <sys/stat.h>
 #include <ctype.h>
+#include <time.h>
 
 #include "dhcp.h"
 #include "cdefs.h"
@@ -70,6 +71,7 @@ struct packet {
 	int client_port;
 	struct iaddr client_addr;
 	int client_sock;
+	struct subnet *subnet;
 	struct {
 		int len;
 		unsigned char *data;
@@ -91,6 +93,10 @@ struct host_decl {
 	char *filename;
 	char *server_name;	
 	struct tree_cache *fixed_addr;
+	struct tree_cache *ciaddr;
+	struct tree_cache *yiaddr;
+	struct tree_cache *siaddr;
+	struct tree_cache *giaddr;
 	struct tree_cache *options [256];
 };
 
@@ -106,13 +112,18 @@ struct lease {
 	struct subnet *contain;
 	struct hardware hardware_addr;
 	int state;
+	int xid;
 };
 
 struct subnet {
+	struct subnet *next;
 	struct iaddr net;
 	struct iaddr netmask;
+	TIME default_lease_time;
+	TIME max_lease_time;
 	struct lease *leases;
 	struct lease *insertion_point;
+	struct lease *last_lease;
 };
 
 /* Bitmask of dhcp option codes. */
@@ -162,6 +173,8 @@ int parse_warn PROTO ((char *, ...));
 
 /* dhcpd.c */
 TIME cur_time;
+TIME default_lease_time;
+TIME max_lease_time;
 extern u_int32_t *server_addrlist;
 extern int server_addrcount;
 extern u_int16_t server_port;
@@ -225,8 +238,11 @@ extern struct subnet *find_subnet (struct iaddr);
 void enter_subnet (struct subnet *);
 void enter_lease PROTO ((struct lease *));
 void supersede_lease PROTO ((struct lease *, struct lease *));
+void release_lease PROTO ((struct lease *));
 struct lease *find_lease_by_uid PROTO ((unsigned char *, int));
+struct lease *find_lease_by_hw_addr PROTO ((unsigned char *, int));
 struct lease *find_lease_by_ip_addr PROTO ((struct iaddr));
+void dump_subnets PROTO ((void));
 
 /* alloc.c */
 VOIDPTR dmalloc PROTO ((int, char *));
@@ -251,6 +267,7 @@ void free_tree PROTO ((struct tree *, char *));
 
 /* print.c */
 char *print_hw_addr PROTO ((int, int, unsigned char *));
+void print_lease PROTO ((struct lease *));
 
 /* socket.c */
 u_int32_t *get_interface_list PROTO ((int *));
diff --git a/dhctoken.h b/dhctoken.h
index f04fae5b..e3132f99 100644
--- a/dhctoken.h
+++ b/dhctoken.h
@@ -64,7 +64,11 @@
 #define LEASE		271
 #define RANGE		272
 #define PACKET		273
-#define LAST_TOKEN	PACKET
+#define CIADDR		274
+#define YIADDR		275
+#define SIADDR		276
+#define GIADDR		277
+#define LAST_TOKEN	GIADDR
 
 #define is_identifier(x)	((x) >= FIRST_TOKEN &&	\
 				 (x) <= LAST_TOKEN &&	\
diff --git a/hash.c b/hash.c
index 8bc724e7..cf15ba31 100644
--- a/hash.c
+++ b/hash.c
@@ -103,6 +103,7 @@ void add_hash (table, name, len, pointer)
 	bp -> name = name;
 	bp -> value = pointer;
 	bp -> next = table -> buckets [hashno];
+	bp -> len = len;
 	table -> buckets [hashno] = bp;
 }
 
@@ -140,10 +141,11 @@ unsigned char *hash_lookup (table, name, len)
 	struct hash_bucket *bp;
 
 	if (len) {
-		for (bp = table -> buckets [hashno]; bp; bp = bp -> next)
+		for (bp = table -> buckets [hashno]; bp; bp = bp -> next) {
 			if (len == bp -> len
 			    && !memcmp (bp -> name, name, len))
 				return bp -> value;
+		}
 	} else {
 		for (bp = table -> buckets [hashno]; bp; bp = bp -> next)
 			if (!strcmp (bp -> name, name))
diff --git a/includes/dhcpd.h b/includes/dhcpd.h
index 655b57eb..81d5cccc 100644
--- a/includes/dhcpd.h
+++ b/includes/dhcpd.h
@@ -53,6 +53,7 @@
 #include <stdlib.h>
 #include <sys/stat.h>
 #include <ctype.h>
+#include <time.h>
 
 #include "dhcp.h"
 #include "cdefs.h"
@@ -70,6 +71,7 @@ struct packet {
 	int client_port;
 	struct iaddr client_addr;
 	int client_sock;
+	struct subnet *subnet;
 	struct {
 		int len;
 		unsigned char *data;
@@ -91,6 +93,10 @@ struct host_decl {
 	char *filename;
 	char *server_name;	
 	struct tree_cache *fixed_addr;
+	struct tree_cache *ciaddr;
+	struct tree_cache *yiaddr;
+	struct tree_cache *siaddr;
+	struct tree_cache *giaddr;
 	struct tree_cache *options [256];
 };
 
@@ -106,13 +112,18 @@ struct lease {
 	struct subnet *contain;
 	struct hardware hardware_addr;
 	int state;
+	int xid;
 };
 
 struct subnet {
+	struct subnet *next;
 	struct iaddr net;
 	struct iaddr netmask;
+	TIME default_lease_time;
+	TIME max_lease_time;
 	struct lease *leases;
 	struct lease *insertion_point;
+	struct lease *last_lease;
 };
 
 /* Bitmask of dhcp option codes. */
@@ -162,6 +173,8 @@ int parse_warn PROTO ((char *, ...));
 
 /* dhcpd.c */
 TIME cur_time;
+TIME default_lease_time;
+TIME max_lease_time;
 extern u_int32_t *server_addrlist;
 extern int server_addrcount;
 extern u_int16_t server_port;
@@ -225,8 +238,11 @@ extern struct subnet *find_subnet (struct iaddr);
 void enter_subnet (struct subnet *);
 void enter_lease PROTO ((struct lease *));
 void supersede_lease PROTO ((struct lease *, struct lease *));
+void release_lease PROTO ((struct lease *));
 struct lease *find_lease_by_uid PROTO ((unsigned char *, int));
+struct lease *find_lease_by_hw_addr PROTO ((unsigned char *, int));
 struct lease *find_lease_by_ip_addr PROTO ((struct iaddr));
+void dump_subnets PROTO ((void));
 
 /* alloc.c */
 VOIDPTR dmalloc PROTO ((int, char *));
@@ -251,6 +267,7 @@ void free_tree PROTO ((struct tree *, char *));
 
 /* print.c */
 char *print_hw_addr PROTO ((int, int, unsigned char *));
+void print_lease PROTO ((struct lease *));
 
 /* socket.c */
 u_int32_t *get_interface_list PROTO ((int *));
diff --git a/includes/dhctoken.h b/includes/dhctoken.h
index f04fae5b..e3132f99 100644
--- a/includes/dhctoken.h
+++ b/includes/dhctoken.h
@@ -64,7 +64,11 @@
 #define LEASE		271
 #define RANGE		272
 #define PACKET		273
-#define LAST_TOKEN	PACKET
+#define CIADDR		274
+#define YIADDR		275
+#define SIADDR		276
+#define GIADDR		277
+#define LAST_TOKEN	GIADDR
 
 #define is_identifier(x)	((x) >= FIRST_TOKEN &&	\
 				 (x) <= LAST_TOKEN &&	\
diff --git a/inet.c b/inet.c
index fa25efc1..ce63a2b4 100644
--- a/inet.c
+++ b/inet.c
@@ -87,7 +87,7 @@ struct iaddr ip_addr (subnet, mask, host_address)
 	j = rv.len - sizeof habuf;
 	for (i = sizeof habuf - 1; i >= 0; i--) {
 		if (mask.iabuf [i + j]) {
-			if (habuf [i] > ~mask.iabuf [i + j]) {
+			if (habuf [i] > (mask.iabuf [i + j] ^ 0xFF)) {
 				rv.len = 0;
 				return rv;
 			}
@@ -97,10 +97,10 @@ struct iaddr ip_addr (subnet, mask, host_address)
 					return rv;
 				}
 			}
-			rv.iabuf [i + j] &= habuf [i];
+			rv.iabuf [i + j] |= habuf [i];
 			break;
-		}
-		rv.iabuf [i + j] = habuf [i];
+		} else
+			rv.iabuf [i + j] = habuf [i];
 	}
 		
 	return rv;
diff --git a/memory.c b/memory.c
index 21b1c010..13bf3492 100644
--- a/memory.c
+++ b/memory.c
@@ -48,7 +48,7 @@ static char copyright[] =
 #include "dhcpd.h"
 
 static struct host_decl *hosts;
-static struct hash_table *subnet_hash;
+static struct subnet *subnets;
 static struct hash_table *lease_uid_hash;
 static struct hash_table *lease_ip_addr_hash;
 static struct hash_table *lease_hw_addr_hash;
@@ -98,12 +98,10 @@ void new_address_range (low, high, netmask)
 	struct lease *address_range, *lp, *plp;
 	struct subnet *subnet;
 	struct iaddr net;
-	int i, max;
+	int min, max, i;
 	char lowbuf [16], highbuf [16], netbuf [16];
 
 	/* Initialize the hash table if it hasn't been done yet. */
-	if (!subnet_hash)
-		subnet_hash = new_hash ();
 	if (!lease_uid_hash)
 		lease_uid_hash = new_hash ();
 	if (!lease_ip_addr_hash)
@@ -130,32 +128,40 @@ void new_address_range (low, high, netmask)
 		subnet -> net = net;
 		subnet -> netmask = netmask;
 		subnet -> leases = (struct lease *)0;
+		subnet -> last_lease = (struct lease *)0;
+		subnet -> next = (struct subnet *)0;
+		subnet -> default_lease_time = default_lease_time;
+		subnet -> max_lease_time = max_lease_time;
 		enter_subnet (subnet);
 	}
 
 	/* Get the high and low host addresses... */
 	max = host_addr (high, netmask);
-	i = host_addr (low, netmask);
+	min = host_addr (low, netmask);
 
 	/* Allow range to be specified high-to-low as well as low-to-high. */
-	if (i > max) {
-		max = i;
-		i = host_addr (high, netmask);
+	if (min > max) {
+		max = min;
+		min = host_addr (high, netmask);
 	}
 
 	/* Get a lease structure for each address in the range. */
-	address_range = new_leases (max - i + 1, "new_address_range");
+	address_range = new_leases (max - min + 1, "new_address_range");
 	if (!address_range) {
 		strcpy (lowbuf, piaddr (low));
 		strcpy (highbuf, piaddr (high));
 		error ("No memory for address range %s-%s.", lowbuf, highbuf);
 	}
-	memset (address_range, 0, (sizeof *address_range) * (max - i + 1));
+	memset (address_range, 0, (sizeof *address_range) * (max - min + 1));
+
+	/* Fill in the last lease if it hasn't been already... */
+	if (!subnet -> last_lease)
+		subnet -> last_lease = &address_range [0];
 
 	/* Fill out the lease structures with some minimal information. */
-	for (; i <= max; i++) {
+	for (i = 0; i < max - min + 1; i++) {
 		address_range [i].ip_addr =
-			ip_addr (subnet -> net, subnet -> netmask, i);
+			ip_addr (subnet -> net, subnet -> netmask, i + min);
 		address_range [i].starts =
 			address_range [i].timestamp = MIN_TIME;
 		address_range [i].ends = MIN_TIME;
@@ -200,13 +206,16 @@ void new_address_range (low, high, netmask)
 	}
 }
 
-struct subnet *find_subnet (subnet)
-	struct iaddr subnet;
+struct subnet *find_subnet (addr)
+	struct iaddr addr;
 {
 	struct subnet *rv;
 
-	return (struct subnet *)hash_lookup (subnet_hash,
-					     (char *)subnet.iabuf, subnet.len);
+	for (rv = subnets; rv; rv = rv -> next) {
+		if (addr_eq (subnet_number (addr, rv -> netmask), rv -> net))
+			return rv;
+	}
+	return (struct subnet *)0;
 }
 
 /* Enter a new subnet into the subnet hash. */
@@ -214,8 +223,9 @@ struct subnet *find_subnet (subnet)
 void enter_subnet (subnet)
 	struct subnet *subnet;
 {
-	add_hash (subnet_hash, (char *)subnet -> net.iabuf,
-		  subnet -> net.len, (unsigned char *)subnet);
+	/* XXX Sort the nets into a balanced tree to make searching quicker. */
+	subnet -> next = subnets;
+	subnets = subnet;
 }
 	
 /* Enter a lease into the system.   This is called by the parser each
@@ -259,6 +269,11 @@ void supersede_lease (comp, lease)
 	struct subnet *parent;
 	struct lease *lp;
 
+printf ("Supersede_lease:\n");
+print_lease (comp);
+print_lease (lease);
+printf ("\n");
+
 	/* If the existing lease hasn't expired and has a different
 	   unique identifier or, if it doesn't have a unique
 	   identifier, a different hardware address, then the two
@@ -290,7 +305,9 @@ void supersede_lease (comp, lease)
 				enter_uid = 1;
 			}
 			free (comp -> uid);
-		}
+		} else
+			enter_uid = 1;
+
 		if (comp -> hardware_addr.htype &&
 		    ((comp -> hardware_addr.hlen !=
 		      lease -> hardware_addr.hlen) ||
@@ -303,7 +320,8 @@ void supersede_lease (comp, lease)
 					   comp -> hardware_addr.haddr,
 					   comp -> hardware_addr.hlen);
 			enter_hwaddr = 1;
-		}
+		} else if (!comp -> hardware_addr.htype)
+			enter_hwaddr = 1;
 
 		/* Copy the data files, but not the linkages. */
 		comp -> starts = lease -> starts;
@@ -317,16 +335,16 @@ void supersede_lease (comp, lease)
 
 		/* Record the lease in the uid hash if necessary. */
 		if (enter_uid && lease -> uid) {
-			add_hash (lease_uid_hash, lease -> uid,
-				  lease -> uid_len, (unsigned char *)lease);
+			add_hash (lease_uid_hash, comp -> uid,
+				  comp -> uid_len, (unsigned char *)comp);
 		}
 
 		/* Record it in the hardware address hash if necessary. */
 		if (enter_hwaddr && lease -> hardware_addr.htype) {
 			add_hash (lease_hw_addr_hash,
-				  lease -> hardware_addr.haddr,
-				  lease -> hardware_addr.hlen,
-				  (unsigned char *)lease);
+				  comp -> hardware_addr.haddr,
+				  comp -> hardware_addr.hlen,
+				  (unsigned char *)comp);
 		}
 
 		/* Remove the lease from its current place in the list. */
@@ -338,6 +356,9 @@ void supersede_lease (comp, lease)
 		if (comp -> next) {
 			comp -> next -> prev = comp -> prev;
 		}
+		if (comp -> contain -> last_lease == comp) {
+			comp -> contain -> last_lease = comp -> prev;
+		}
 
 		/* Find the last insertion point... */
 		if (comp == comp -> contain -> insertion_point ||
@@ -351,18 +372,20 @@ void supersede_lease (comp, lease)
 			/* Nothing on the list yet?    Just make comp the
 			   head of the list. */
 			comp -> contain -> leases = comp;
-		} else if (lp -> ends <= comp -> ends) {
+			comp -> contain -> last_lease = comp;
+		} else if (lp -> ends > comp -> ends) {
 			/* Skip down the list until we run out of list
 			   or find a place for comp. */
-			while (lp -> next && lp -> ends < comp -> ends) {
+			while (lp -> next && lp -> ends > comp -> ends) {
 				lp = lp -> next;
 			}
-			if (lp -> ends < comp -> ends) {
+			if (lp -> ends > comp -> ends) {
 				/* If we ran out of list, put comp
 				   at the end. */
 				lp -> next = comp;
 				comp -> prev = lp;
 				comp -> next = (struct lease *)0;
+				comp -> contain -> last_lease = comp;
 			} else {
 				/* If we didn't, put it between lp and
 				   the previous item on the list. */
@@ -372,12 +395,12 @@ void supersede_lease (comp, lease)
 				lp -> prev = comp;
 			}
 		} else {
-			/* Skip ip the list until we run out of list
+			/* Skip up the list until we run out of list
 			   or find a place for comp. */
-			while (lp -> prev && lp -> ends > comp -> ends) {
+			while (lp -> prev && lp -> ends < comp -> ends) {
 				lp = lp -> prev;
 			}
-			if (lp -> ends > comp -> ends) {
+			if (lp -> ends < comp -> ends) {
 				/* If we ran out of list, put comp
 				   at the beginning. */
 				lp -> prev = comp;
@@ -397,6 +420,18 @@ void supersede_lease (comp, lease)
 	}
 }
 
+/* Release the specified lease and re-hash it as appropriate. */
+
+void release_lease (lease)
+	struct lease *lease;
+{
+	struct lease lt;
+
+	lease -> ends = 0;
+	lt = *lease;
+	supersede_lease (lease, &lt);
+}
+
 /* Locate the lease associated with a given IP address... */
 
 struct lease *find_lease_by_ip_addr (addr)
@@ -417,3 +452,29 @@ struct lease *find_lease_by_uid (uid, len)
 	return lease;
 }
 
+struct lease *find_lease_by_hw_addr (hwaddr, hwlen)
+	unsigned char *hwaddr;
+	int hwlen;
+{
+	struct lease *lease = (struct lease *)hash_lookup (lease_hw_addr_hash,
+							   hwaddr, hwlen);
+	return lease;
+}
+
+void dump_subnets ()
+{
+	struct lease *l;
+	struct subnet *s;
+	int i;
+
+	for (s = subnets; s; s = s -> next) {
+		printf ("Subnet %s", piaddr (s -> net));
+		printf (" netmask %s\n",
+			piaddr (s -> netmask));
+		for (l = s -> leases; l; l = l -> next) {
+			print_lease (l);
+		}
+		printf ("Last Lease:\n");
+		print_lease (s -> last_lease);
+	}
+}
diff --git a/options.c b/options.c
index 75bfc5e5..f9fa44d3 100644
--- a/options.c
+++ b/options.c
@@ -94,8 +94,6 @@ void parse_option_buffer (packet, buffer, length)
 	int len;
 	int code;
 
-printf ("parse_option_buffer (%x, %x, %d)\n",
-(unsigned long)packet, (unsigned long)buffer, length);
 	for (s = buffer; *s != DHO_END && s < end; ) {
 		code = s [0];
 		/* Pad options don't have a length - just skip them. */
@@ -126,8 +124,6 @@ printf ("parse_option_buffer (%x, %x, %d)\n",
 			t [len] = 0;
 			packet -> options [code].len = len;
 			packet -> options [code].data = t;
-printf ("%s=%s\n", dhcp_options [code].name,
-pretty_print_option (code, t, len));
 		} else {
 			/* If it's a repeat, concatenate it to whatever
 			   we last saw.   This is really only required
diff --git a/print.c b/print.c
index 55d17159..4686e2e3 100644
--- a/print.c
+++ b/print.c
@@ -55,13 +55,46 @@ char *print_hw_addr (htype, hlen, data)
 	char *s;
 	int i;
 
-	s = habuf;
-	for (i = 0; i < hlen; i++) {
-		sprintf (s, "%x", data [i]);
-		s += strlen (s);
-		*s++ = ':';
+	if (htype == 0 || hlen == 0) {
+		strcpy (habuf, "<null>");
+	} else {
+		s = habuf;
+		for (i = 0; i < hlen; i++) {
+			sprintf (s, "%x", data [i]);
+			s += strlen (s);
+			*s++ = ':';
+		}
+		*--s = 0;
 	}
-	*--s = 0;
 	return habuf;
 }
 
+void print_lease (lease)
+	struct lease *lease;
+{
+	struct tm *t;
+	char tbuf [32];
+
+	printf ("  Lease %s",
+		piaddr (lease -> ip_addr));
+	
+	t = gmtime (&lease -> starts);
+	strftime (tbuf, sizeof tbuf, "%D %H:%M:%S", t);
+	printf ("  start %s", tbuf);
+	
+	t = gmtime (&lease -> ends);
+	strftime (tbuf, sizeof tbuf, "%D %H:%M:%S", t);
+	printf ("  end %s", tbuf);
+	
+	t = gmtime (&lease -> timestamp);
+	strftime (tbuf, sizeof tbuf, "%D %H:%M:%S", t);
+	printf ("  stamp %s\n", tbuf);
+	
+	printf ("    hardware addr = %s",
+		print_hw_addr (lease -> hardware_addr.htype,
+			       lease -> hardware_addr.hlen,
+			       lease -> hardware_addr.haddr));
+	printf ("  host %s  state %x\n",
+		lease -> host ? lease -> host -> name : "<none>",
+		lease -> state);
+}	
diff --git a/server/confpars.c b/server/confpars.c
index 7335de6f..1be52bb9 100644
--- a/server/confpars.c
+++ b/server/confpars.c
@@ -234,6 +234,22 @@ void parse_host_decl (cfile, bc, decl)
 	      case OPTION:
 		parse_option_decl (cfile, bc, decl);
 		break;
+	      case CIADDR:
+		decl -> ciaddr =
+			tree_cache (parse_ip_addr_or_hostname (cfile, bc, 0));
+		break;
+	      case YIADDR:
+		decl -> yiaddr =
+			tree_cache (parse_ip_addr_or_hostname (cfile, bc, 0));
+		break;
+	      case SIADDR:
+		decl -> siaddr =
+			tree_cache (parse_ip_addr_or_hostname (cfile, bc, 0));
+		break;
+	      case GIADDR:
+		decl -> giaddr =
+			tree_cache (parse_ip_addr_or_hostname (cfile, bc, 0));
+		break;
 	      default:
 		parse_warn ("expecting a dhcp option declaration.");
 		skip_to_semi (cfile);
diff --git a/server/dhcp.c b/server/dhcp.c
index fa49eccc..640c726f 100644
--- a/server/dhcp.c
+++ b/server/dhcp.c
@@ -49,5 +49,205 @@ static char copyright[] =
 void dhcp (packet)
 	struct packet *packet;
 {
+	struct lease *uid_lease, *ip_lease, *hw_lease, *lease;
+	struct iaddr cip;
+	struct lease lt;
+	TIME lease_time;
+
 	dump_packet (packet);
+
+	/* Try to find a lease that's been assigned to the specified
+	   unique client identifier. */
+	if (packet -> options [DHO_DHCP_CLIENT_IDENTIFIER].len)
+		uid_lease =
+			find_lease_by_uid (packet -> options
+					   [DHO_DHCP_CLIENT_IDENTIFIER].data,
+					   packet -> options
+					   [DHO_DHCP_CLIENT_IDENTIFIER].len);
+	else
+		uid_lease = (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,
+					  packet -> raw -> hlen);
+
+	/* 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
+	    <= sizeof cip.iabuf) {
+		cip.len = packet -> options [DHO_DHCP_REQUESTED_ADDRESS].len;
+		memcpy (cip.iabuf,
+			packet -> options [DHO_DHCP_REQUESTED_ADDRESS].data,
+			packet -> options [DHO_DHCP_REQUESTED_ADDRESS].len);
+		memcpy (cip.iabuf, &packet -> raw -> ciaddr, 4);
+		ip_lease = find_lease_by_ip_addr (cip);
+	} else
+		ip_lease = (struct lease *)0;
+
+	printf ("First blush:\n");
+	if (ip_lease) {
+		printf ("ip_lease: ");
+		print_lease (ip_lease);
+	}
+	if (hw_lease) {
+		printf ("hw_lease: ");
+		print_lease (hw_lease);
+	}
+	if (uid_lease) {
+		printf ("uid_lease: ");
+		print_lease (uid_lease);
+	}
+
+	/* 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 == uid_lease)
+		ip_lease = (struct lease *)0;
+
+	printf ("Second blush:\n");
+	if (ip_lease) {
+		printf ("ip_lease: ");
+		print_lease (ip_lease);
+	}
+	if (hw_lease) {
+		printf ("hw_lease: ");
+		print_lease (hw_lease);
+	}
+	if (uid_lease) {
+		printf ("uid_lease: ");
+		print_lease (uid_lease);
+	}
+
+	/* 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;
+
+	/* Now eliminate leases that are on the wrong subnet... */
+	if (ip_lease && packet -> subnet != ip_lease -> contain) {
+		release_lease (ip_lease);
+		ip_lease = (struct lease *)0;
+	}
+	if (uid_lease && packet -> subnet != uid_lease -> contain) {
+		release_lease (uid_lease);
+		uid_lease = (struct lease *)0;
+	}
+	if (hw_lease && packet -> subnet != hw_lease -> contain) {
+		release_lease (hw_lease);
+		hw_lease = (struct lease *)0;
+	}
+
+	printf ("Third blush:\n");
+	if (ip_lease) {
+		printf ("ip_lease: ");
+		print_lease (ip_lease);
+	}
+	if (hw_lease) {
+		printf ("hw_lease: ");
+		print_lease (hw_lease);
+	}
+	if (uid_lease) {
+		printf ("uid_lease: ");
+		print_lease (uid_lease);
+	}
+
+	/* At this point, if ip_lease is nonzero, we can assign it to
+	   this client. */
+	lease = ip_lease;
+
+	/* If we got a lease that matched the client identifier, we may want
+	   to use it, but if we already have a lease we like, we must free
+	   the lease that matched the client identifier. */
+	if (uid_lease) {
+		if (lease) {
+			release_lease (uid_lease);
+		} else
+			lease = uid_lease;
+	}
+
+	/* The lease that matched the hardware address is treated likewise. */
+	if (hw_lease) {
+		if (lease) {
+			release_lease (hw_lease);
+		} else
+			lease = hw_lease;
+	}
+
+	/* If we didn't find a lease, try to allocate one... */
+	if (!lease) {
+		lease = packet -> subnet -> last_lease;
+
+		/* If there are no leases in that subnet that have
+		   expired, we have nothing to offer this client. */
+		if (lease -> ends >= cur_time) {
+			note ("no free leases on subnet %s",
+			      piaddr (packet -> subnet -> net));
+			return;
+		}
+		lease -> host = (struct host_decl *)0;
+	}
+
+	/* At this point, we have a lease that we can offer the client.
+	   Now we construct a lease structure that contains what we want,
+	   and call supersede_lease to do the right thing with it. */
+
+	memset (&lt, 0, sizeof lt);
+
+	/* Use the ip address of the lease that we finally found in
+	   the database. */
+	lt.ip_addr = lease -> ip_addr;
+
+	/* Start now. */
+	lt.starts = cur_time;
+
+	/* Figure out how long a lease to assign. */
+	if (packet -> options [DHO_DHCP_LEASE_TIME].len == 4) {
+		lease_time = getULong (packet ->
+				       options [DHO_DHCP_LEASE_TIME].data);
+
+		/* Don't let the client ask for a longer lease than
+		   is supported for this subnet. */
+		if (lease_time > packet -> subnet -> max_lease_time)
+			lease_time = packet -> subnet -> max_lease_time;
+	} else
+		lease_time = packet -> subnet -> default_lease_time;
+	lt.ends = cur_time + lease_time;
+
+	lt.timestamp = cur_time;
+
+	/* Record the uid, if given... */
+	if (packet -> options [DHO_DHCP_CLIENT_IDENTIFIER].len) {
+		lt.uid_len =
+			packet -> options [DHO_DHCP_CLIENT_IDENTIFIER].len;
+		lt.uid = packet -> options [DHO_DHCP_CLIENT_IDENTIFIER].data;
+		packet -> options [DHO_DHCP_CLIENT_IDENTIFIER].data =
+			(unsigned char *)0;
+		packet -> options [DHO_DHCP_CLIENT_IDENTIFIER].len = 0;
+	}
+
+	/* Record the hardware address, if given... */
+	lt.hardware_addr.hlen = packet -> raw -> hlen;
+	lt.hardware_addr.htype = packet -> raw -> htype;
+	memcpy (lt.hardware_addr.haddr, packet -> raw -> chaddr,
+		packet -> raw -> hlen);
+
+	lt.host = lease -> host; /* XXX */
+	lt.contain = lease -> contain;
+
+	/* Record the transaction id... */
+	lt.xid = packet -> raw -> xid;
+
+	/* Install the new information about this lease in the database. */
+	supersede_lease (lease, &lt);
+
+	/* Send a response to the client... */
+	dump_subnets ();
 }
diff --git a/server/dhcpd.c b/server/dhcpd.c
index b9e527c8..159d3b85 100644
--- a/server/dhcpd.c
+++ b/server/dhcpd.c
@@ -50,7 +50,10 @@ static char copyright[] =
 static void usage PROTO ((void));
 
 TIME cur_time;
+TIME default_lease_time = 43200; /* 12 hours... */
+TIME max_lease_time = 86400; /* 24 hours... */
 
+struct subnet *local_subnet;
 u_int32_t *server_addrlist;
 int server_addrcount;
 u_int16_t server_port;
@@ -63,6 +66,7 @@ int main (argc, argv, envp)
 	int port = 0;
 	int i;
 	struct sockaddr_in name;
+	struct iaddr taddr;
 	u_int32_t *addrlist = (u_int32_t *)0;
 	int addrcount = 0;
 	struct tree *addrtree = (struct tree *)0;
@@ -148,7 +152,23 @@ int main (argc, argv, envp)
 	}
 #endif
 
+	taddr.len = 0;
 	server_addrlist = get_interface_list (&server_addrcount);
+	for (i = 0; i < server_addrcount; i++) {
+		struct sockaddr_in foo;
+		foo.sin_addr.s_addr = server_addrlist [i];
+		printf ("Address %d: %s\n", i, inet_ntoa (foo.sin_addr));
+
+		if (server_addrlist [i] != htonl (INADDR_LOOPBACK)) {
+			if (taddr.len) {
+				error ("dhcpd currently does not support "
+				       "multiple interfaces");
+			}
+			taddr.len = 4;
+			memcpy (taddr.iabuf, &server_addrlist [i], 4);
+			local_subnet = find_subnet (taddr);
+		}
+	}
 
 	/* Listen on the specified (or default) port on each specified
 	   (or default) IP address. */
@@ -164,6 +184,8 @@ int main (argc, argv, envp)
 		close (i);
 	}
 
+	dump_subnets ();
+
 	/* Receive packets and dispatch them... */
 	dispatch ();
 
@@ -191,6 +213,7 @@ void do_packet (packbuf, len, from_port, from, sock)
 {
 	struct packet *tp;
 	struct dhcp_packet *tdp;
+	struct iaddr ia;
 
 	if (!(tp = new_packet ("do_packet")))
 		return;
@@ -205,12 +228,29 @@ void do_packet (packbuf, len, from_port, from, sock)
 	tp -> client_port = from_port;
 	tp -> client_addr = from;
 	tp -> client_sock = sock;
-	parse_options (tp);
-	if (tp -> options_valid &&
-	    tp -> options [DHO_DHCP_MESSAGE_TYPE].data)
-		dhcp (tp);
-	else
-		bootp (tp);
+	
+	/* If this came through a gateway, find the corresponding subnet... */
+	if (tp -> raw -> giaddr.s_addr) {
+		ia.len = 4;
+		memcpy (ia.iabuf, &tp -> raw -> giaddr, 4);
+		tp -> subnet = find_subnet (ia);
+	} else {
+		tp -> subnet = local_subnet;
+	}
+
+	/* If the subnet from whence this packet came is unknown to us,
+	   drop it on the floor... */
+	if (!tp -> subnet)
+		note ("Packet from unknown subnet: %s",
+		      inet_ntoa (tp -> raw -> giaddr));
+	else {
+		parse_options (tp);
+		if (tp -> options_valid &&
+		    tp -> options [DHO_DHCP_MESSAGE_TYPE].data)
+			dhcp (tp);
+		else
+			bootp (tp);
+	}
 }
 
 void dump_packet (tp)
diff --git a/server/dhcpd.conf b/server/dhcpd.conf
index 10d66a37..bc8a1d77 100644
--- a/server/dhcpd.conf
+++ b/server/dhcpd.conf
@@ -1,4 +1,5 @@
-range 204.254.239.11 204.254.239.254 255.255.255.0;
+range 204.254.239.11 204.254.239.17 255.255.255.0;
+range 204.254.240.11 204.254.240.12 255.255.255.0;
 
 host minuet
 	hardware ethernet 08:00:2b:35:0c:18
diff --git a/socket.c b/socket.c
index 3a013cf0..c69e68cc 100644
--- a/socket.c
+++ b/socket.c
@@ -184,6 +184,9 @@ void dispatch ()
 		/* Wait for a packet or a timeout... XXX */
 		count = select (max + 1, &r, &w, &x, (struct timeval *)0);
 
+		/* Get the current time... */
+		GET_TIME (&cur_time);
+
 		/* Not likely to be transitory... */
 		if (count < 0)
 			error ("select: %m");