X-Git-Url: http://git.archive.openwrt.org/?p=project%2Fodhcpd.git;a=blobdiff_plain;f=src%2Fdhcpv4.c;h=3002c1e1721f63bf17e1a6b37cdcdebd63bf8b71;hp=1807c68b02ab9933dcdfc09a1498d155853444fe;hb=d834ae3ca59cf75cd7f26a5201a7223eaa468fbb;hpb=ee243b09f3c81f824cc463c1c757e905f882350e

diff --git a/src/dhcpv4.c b/src/dhcpv4.c
index 1807c68..3002c1e 100644
--- a/src/dhcpv4.c
+++ b/src/dhcpv4.c
@@ -1,5 +1,6 @@
 /**
  * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
+ * Copyright (C) 2016 Hans Dedecker <dedeckeh@gmail.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License v2 as published by
@@ -28,49 +29,50 @@
 #include <sys/timerfd.h>
 #include <arpa/inet.h>
 
+#include <libubox/md5.h>
+
 #include "odhcpd.h"
 #include "dhcpv4.h"
 #include "dhcpv6.h"
 
-
+static void dhcpv4_netevent_cb(unsigned long event, struct netevent_handler_info *info);
+static int setup_dhcpv4_addresses(struct interface *iface);
+static void update_static_assignments(struct interface *iface);
+static void valid_until_cb(struct uloop_timeout *event);
+static void handle_addrlist_change(struct interface *iface);
+static void free_dhcpv4_assignment(struct dhcpv4_assignment *a);
+static void dhcpv4_fr_start(struct dhcpv4_assignment *a);
+static void dhcpv4_fr_stop(struct dhcpv4_assignment *a);
 static void handle_dhcpv4(void *addr, void *data, size_t len,
 		struct interface *iface, void *dest_addr);
 static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
-		enum dhcpv4_msg msg, const uint8_t *mac, struct in_addr reqaddr,
-		const char *hostname);
-
-// Create socket and register events
-int init_dhcpv4(void)
+		enum dhcpv4_msg msg, const uint8_t *mac, const uint32_t reqaddr,
+		uint32_t *leasetime, const char *hostname, const size_t hostname_len,
+		const bool accept_fr_nonce, bool *incl_fr_opt, uint32_t *fr_serverid);
+
+static struct netevent_handler dhcpv4_netevent_handler = { .cb = dhcpv4_netevent_cb, };
+static struct uloop_timeout valid_until_timeout = {.cb = valid_until_cb};
+static uint32_t serial = 0;
+
+struct odhcpd_ref_ip {
+	struct list_head head;
+	int ref_cnt;
+	struct odhcpd_ipaddr addr;
+};
+
+/* Create socket and register events */
+int dhcpv4_init(void)
 {
+	uloop_timeout_set(&valid_until_timeout, 1000);
+	netlink_add_netevent_handler(&dhcpv4_netevent_handler);
+
 	return 0;
 }
 
-char *dhcpv4_msg_to_string(uint8_t reqmsg)
+int dhcpv4_setup_interface(struct interface *iface, bool enable)
 {
-	switch (reqmsg) {
-	case (DHCPV4_MSG_DISCOVER):
-		return "DHCPV4_MSG_DISCOVER";
-	case (DHCPV4_MSG_OFFER):
-		return "DHCPV4_MSG_OFFER";
-	case (DHCPV4_MSG_REQUEST):
-		return "DHCPV4_MSG_REQUEST";
-	case (DHCPV4_MSG_DECLINE):
-		return "DHCPV4_MSG_DECLINE";
-	case (DHCPV4_MSG_ACK):
-		return "DHCPV4_MSG_ACK";
-	case (DHCPV4_MSG_NAK):
-		return "DHCPV4_MSG_NAK";
-	case (DHCPV4_MSG_RELEASE):
-		return "DHCPV4_MSG_RELEASE";
-	case (DHCPV4_MSG_INFORM):
-		return "DHCPV4_MSG_INFORM";
-	default:
-		return "UNKNOWN";
-	}
-}
+	int ret = 0;
 
-int setup_dhcpv4_interface(struct interface *iface, bool enable)
-{
 	if (iface->dhcpv4_event.uloop.fd > 0) {
 		uloop_fd_delete(&iface->dhcpv4_event.uloop);
 		close(iface->dhcpv4_event.uloop.fd);
@@ -78,164 +80,423 @@ int setup_dhcpv4_interface(struct interface *iface, bool enable)
 	}
 
 	if (iface->dhcpv4 && enable) {
+		struct sockaddr_in bind_addr = {AF_INET, htons(DHCPV4_SERVER_PORT),
+					{INADDR_ANY}, {0}};
+		int val = 1;
+
 		if (!iface->dhcpv4_assignments.next)
 			INIT_LIST_HEAD(&iface->dhcpv4_assignments);
 
-		int sock = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
-		if (sock < 0) {
-			syslog(LOG_ERR, "Failed to create DHCPv4 server socket: %s",
-					strerror(errno));
-			return -1;
+		if (!iface->dhcpv4_fr_ips.next)
+			INIT_LIST_HEAD(&iface->dhcpv4_fr_ips);
+
+		iface->dhcpv4_event.uloop.fd = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
+		if (iface->dhcpv4_event.uloop.fd < 0) {
+			syslog(LOG_ERR, "socket(AF_INET): %m");
+			ret = -1;
+			goto out;
 		}
 
-		// Basic IPv6 configuration
-		int val = 1;
-		setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
-		setsockopt(sock, SOL_SOCKET, SO_BROADCAST, &val, sizeof(val));
-		setsockopt(sock, IPPROTO_IP, IP_PKTINFO, &val, sizeof(val));
+		/* Basic IPv4 configuration */
+		if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_REUSEADDR,
+					&val, sizeof(val)) < 0) {
+			syslog(LOG_ERR, "setsockopt(SO_REUSEADDR): %m");
+			ret = -1;
+			goto out;
+		}
+
+		if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_BROADCAST,
+					&val, sizeof(val)) < 0) {
+			syslog(LOG_ERR, "setsockopt(SO_BROADCAST): %m");
+			ret = -1;
+			goto out;
+		}
+
+		if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_PKTINFO,
+					&val, sizeof(val)) < 0) {
+			syslog(LOG_ERR, "setsockopt(IP_PKTINFO): %m");
+			ret = -1;
+			goto out;
+		}
 
 		val = IPTOS_PREC_INTERNETCONTROL;
-		setsockopt(sock, IPPROTO_IP, IP_TOS, &val, sizeof(val));
+		if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_TOS,
+					&val, sizeof(val)) < 0) {
+			syslog(LOG_ERR, "setsockopt(IP_TOS): %m");
+			ret = -1;
+			goto out;
+		}
 
 		val = IP_PMTUDISC_DONT;
-		setsockopt(sock, IPPROTO_IP, IP_MTU_DISCOVER, &val, sizeof(val));
+		if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_MTU_DISCOVER,
+					&val, sizeof(val)) < 0) {
+			syslog(LOG_ERR, "setsockopt(IP_MTU_DISCOVER): %m");
+			ret = -1;
+			goto out;
+		}
 
-		setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE,
-				iface->ifname, strlen(iface->ifname));
+		if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_BINDTODEVICE,
+					iface->ifname, strlen(iface->ifname)) < 0) {
+			syslog(LOG_ERR, "setsockopt(SO_BINDTODEVICE): %m");
+			ret = -1;
+			goto out;
+		}
 
-		struct sockaddr_in bind_addr = {AF_INET, htons(DHCPV4_SERVER_PORT),
-					{INADDR_ANY}, {0}};
+		if (bind(iface->dhcpv4_event.uloop.fd, (struct sockaddr*)&bind_addr,
+					sizeof(bind_addr)) < 0) {
+			syslog(LOG_ERR, "bind(): %m");
+			ret = -1;
+			goto out;
+		}
 
-		if (bind(sock, (struct sockaddr*)&bind_addr, sizeof(bind_addr))) {
-			syslog(LOG_ERR, "Failed to open DHCPv4 server socket: %s",
-					strerror(errno));
-			return -1;
+		if (setup_dhcpv4_addresses(iface) < 0) {
+			ret = -1;
+			goto out;
 		}
 
+		iface->dhcpv4_event.handle_dgram = handle_dhcpv4;
+		odhcpd_register(&iface->dhcpv4_event);
+
+		update_static_assignments(iface);
+	} else if (iface->dhcpv4_assignments.next) {
+		while (!list_empty(&iface->dhcpv4_assignments))
+			free_dhcpv4_assignment(list_first_entry(&iface->dhcpv4_assignments,
+							struct dhcpv4_assignment, head));
+	}
+
+out:
+	if (ret < 0 && iface->dhcpv4_event.uloop.fd > 0) {
+		close(iface->dhcpv4_event.uloop.fd);
+		iface->dhcpv4_event.uloop.fd = -1;
+	}
+
+	return ret;
+}
+
+
+static void dhcpv4_netevent_cb(unsigned long event, struct netevent_handler_info *info)
+{
+	struct interface *iface = info->iface;
+
+	if (!iface || iface->dhcpv4 == MODE_DISABLED)
+		return;
+
+	switch (event) {
+	case NETEV_IFINDEX_CHANGE:
+		dhcpv4_setup_interface(iface, true);
+		break;
+	case NETEV_ADDRLIST_CHANGE:
+		handle_addrlist_change(iface);
+		break;
+	default:
+		break;
+	}
+}
+
+static struct dhcpv4_assignment *find_assignment_by_hwaddr(struct interface *iface, const uint8_t *hwaddr)
+{
+	struct dhcpv4_assignment *a;
+
+	list_for_each_entry(a, &iface->dhcpv4_assignments, head)
+		if (!memcmp(a->hwaddr, hwaddr, 6))
+			return a;
+
+	return NULL;
+}
+
+static struct dhcpv4_assignment *find_assignment_by_addr(struct interface *iface, const uint32_t addr)
+{
+	struct dhcpv4_assignment *a;
+
+	list_for_each_entry(a, &iface->dhcpv4_assignments, head)
+		if (a->addr == addr)
+			return a;
+
+	return NULL;
+}
+
+static int setup_dhcpv4_addresses(struct interface *iface)
+{
+	iface->dhcpv4_start_ip.s_addr = INADDR_ANY;
+	iface->dhcpv4_end_ip.s_addr = INADDR_ANY;
+	iface->dhcpv4_local.s_addr = INADDR_ANY;
+	iface->dhcpv4_bcast.s_addr = INADDR_ANY;
+	iface->dhcpv4_mask.s_addr = INADDR_ANY;
+
+	/* Sanity checks */
+	if (iface->dhcpv4_start.s_addr & htonl(0xffff0000) ||
+	    iface->dhcpv4_end.s_addr & htonl(0xffff0000) ||
+	    ntohl(iface->dhcpv4_start.s_addr) > ntohl(iface->dhcpv4_end.s_addr)) {
+		syslog(LOG_ERR, "invalid DHCP range for %s", iface->name);
+		return -1;
+	}
+
+	if (!iface->addr4_len) {
+		syslog(LOG_WARNING, "no network(s) available on %s", iface->name);
+		return -1;
+	}
+
+	uint32_t start = ntohl(iface->dhcpv4_start.s_addr);
+	uint32_t end = ntohl(iface->dhcpv4_end.s_addr);
 
-		if (ntohl(iface->dhcpv4_start.s_addr) > ntohl(iface->dhcpv4_end.s_addr)) {
-			syslog(LOG_ERR, "Invalid DHCP range");
-			return -1;
+	for (size_t i = 0; i < iface->addr4_len && start && end; i++) {
+		struct in_addr *addr = &iface->addr4[i].addr.in;
+		struct in_addr mask;
+
+		odhcpd_bitlen2netmask(false, iface->addr4[i].prefix, &mask);
+		if ((start & ntohl(~mask.s_addr)) == start &&
+			    (end & ntohl(~mask.s_addr)) == end) {
+			iface->dhcpv4_start_ip.s_addr = htonl(start) |
+							(addr->s_addr & mask.s_addr);
+			iface->dhcpv4_end_ip.s_addr = htonl(end) |
+							(addr->s_addr & mask.s_addr);
+			iface->dhcpv4_local = *addr;
+			iface->dhcpv4_bcast = iface->addr4[i].broadcast;
+			iface->dhcpv4_mask = mask;
+			return 0;
 		}
+	}
 
-		// Create a range if not specified
-		struct ifreq ifreq;
-		strncpy(ifreq.ifr_name, iface->ifname, sizeof(ifreq.ifr_name));
-
-		struct sockaddr_in *saddr = (struct sockaddr_in*)&ifreq.ifr_addr;
-		struct sockaddr_in *smask = (struct sockaddr_in*)&ifreq.ifr_netmask;
-		if (!(iface->dhcpv4_start.s_addr & htonl(0xffff0000)) &&
-				!(iface->dhcpv4_end.s_addr & htonl(0xffff0000)) &&
-				!ioctl(sock, SIOCGIFADDR, &ifreq)) {
-			struct in_addr addr = saddr->sin_addr;
-
-			ioctl(sock, SIOCGIFNETMASK, &ifreq);
-			struct in_addr mask = smask->sin_addr;
-
-			uint32_t start = ntohl(iface->dhcpv4_start.s_addr);
-			uint32_t end = ntohl(iface->dhcpv4_end.s_addr);
-
-			if (start && end && start < end &&
-					start > ntohl(addr.s_addr & ~mask.s_addr) &&
-					(start & ntohl(~mask.s_addr)) == start &&
-					(end & ntohl(~mask.s_addr)) == end) {
-				iface->dhcpv4_start.s_addr = htonl(start) |
-						(addr.s_addr & mask.s_addr);
-				iface->dhcpv4_end.s_addr = htonl(end) |
-						(addr.s_addr & mask.s_addr);
-			} else if (ntohl(mask.s_addr) <= 0xfffffff0) {
-				start = addr.s_addr & mask.s_addr;
-				end = addr.s_addr & mask.s_addr;
-
-				if (ntohl(mask.s_addr) <= 0xffffff00) {
-					iface->dhcpv4_start.s_addr = start | htonl(100);
-					iface->dhcpv4_end.s_addr = end | htonl(250);
-				} else if (ntohl(mask.s_addr) <= 0xffffffc0) {
-					iface->dhcpv4_start.s_addr = start | htonl(10);
-					iface->dhcpv4_end.s_addr = end | htonl(60);
-				} else if (ntohl(mask.s_addr) <= 0xffffffe0) {
-					iface->dhcpv4_start.s_addr = start | htonl(10);
-					iface->dhcpv4_end.s_addr = end | htonl(30);
-				} else {
-					iface->dhcpv4_start.s_addr = start | htonl(3);
-					iface->dhcpv4_end.s_addr = end | htonl(12);
-				}
-			}
+	/* Don't allocate IP range for subnets bigger than 28 */
+	if (iface->addr4[0].prefix > 28) {
+		syslog(LOG_WARNING, "auto allocation of DHCP range fails on %s", iface->name);
+		return -1;
+	}
 
+	iface->dhcpv4_local = iface->addr4[0].addr.in;
+	iface->dhcpv4_bcast = iface->addr4[0].broadcast;
+	odhcpd_bitlen2netmask(false, iface->addr4[0].prefix, &iface->dhcpv4_mask);
+	end = start = iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr;
+
+	/* Auto allocate ranges */
+	if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffff00) {
+		iface->dhcpv4_start_ip.s_addr = start | htonl(100);
+		iface->dhcpv4_end_ip.s_addr = end | htonl(250);
+	} else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffc0) {
+		iface->dhcpv4_start_ip.s_addr = start | htonl(10);
+		iface->dhcpv4_end_ip.s_addr = end | htonl(60);
+	} else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffe0) {
+		iface->dhcpv4_start_ip.s_addr = start | htonl(10);
+		iface->dhcpv4_end_ip.s_addr = end | htonl(30);
+	} else {
+		iface->dhcpv4_start_ip.s_addr = start | htonl(3);
+		iface->dhcpv4_end_ip.s_addr = end | htonl(12);
+	}
 
+	return 0;
+}
+
+static void update_static_assignments(struct interface *iface)
+{
+	struct dhcpv4_assignment *a, *c;
+
+	/* Cleanup static entries not belonging to the network */
+	list_for_each_entry_safe(a, c, &iface->dhcpv4_assignments, head) {
+		if ((a->flags & OAF_STATIC) &&
+				((a->addr & iface->dhcpv4_mask.s_addr) !=
+				 (iface->dhcpv4_start.s_addr & iface->dhcpv4_mask.s_addr)))
+			free_dhcpv4_assignment(a);
+	}
+
+	/* Parse static entries */
+	struct lease *lease;
+	list_for_each_entry(lease, &leases, head) {
+		if ((iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr) !=
+				(lease->ipaddr.s_addr & iface->dhcpv4_mask.s_addr)) {
+			continue;
 		}
 
-		// Parse static entries
-		struct lease *lease;
-		list_for_each_entry(lease, &leases, head) {
-			// Construct entry
-			size_t hostlen = strlen(lease->hostname) + 1;
-			struct dhcpv4_assignment *a = calloc(1, sizeof(*a) + hostlen);
+		a = find_assignment_by_hwaddr(iface, lease->mac.ether_addr_octet);
+
+		if (!a) {
+			/* Check if there's an assignment with the specified IP address */
+			if (find_assignment_by_addr(iface, lease->ipaddr.s_addr))
+				continue;
+
+			/* Construct entry */
+			a = calloc(1, sizeof(*a));
 			if (!a) {
 				syslog(LOG_ERR, "Calloc failed for static lease on interface %s",
 					iface->ifname);
-				return -1;
+				continue;
 			}
-			a->addr = ntohl(lease->ipaddr.s_addr);
 			memcpy(a->hwaddr, lease->mac.ether_addr_octet, sizeof(a->hwaddr));
-			memcpy(a->hostname, lease->hostname, hostlen);
-			a->valid_until = LONG_MAX;
-
-			// Assign to all interfaces
-			struct dhcpv4_assignment *c;
-			list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
-				if (c->addr > a->addr) {
-					list_add_tail(&a->head, &c->head);
-					break;
-				} else if (c->addr == a->addr) {
-					// Already an assignment with that number
-					break;
-				}
-			}
-			if (&c->head == &iface->dhcpv4_assignments) {
-				list_add(&a->head, &iface->dhcpv4_assignments);
+		}
+
+		a->leasetime = lease->dhcpv4_leasetime;
+
+		a->addr = lease->ipaddr.s_addr;
+		/* Static assignment */
+		a->flags |= OAF_STATIC;
+		/* Infinite valid */
+		a->valid_until = 0;
+		a->iface = iface;
+		if (lease->hostname[0]) {
+			free(a->hostname);
+			a->hostname = strdup(lease->hostname);
+		}
+
+		/* Assign to all interfaces */
+		list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
+			if (ntohl(c->addr) > ntohl(a->addr)) {
+				list_add_tail(&a->head, &c->head);
+				break;
 			}
+		}
+
+		if (&c->head == &iface->dhcpv4_assignments)
+			list_add(&a->head, &iface->dhcpv4_assignments);
+	}
+}
+
+static void inc_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct odhcpd_ref_ip *ip)
+{
+	*ptr = ip;
+	ip->ref_cnt++;
+}
+
+static void decr_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct interface *iface)
+{
+	struct odhcpd_ref_ip *ip = *ptr;
 
-			if (!a->head.next)
-				free(a);
+	if (--ip->ref_cnt == 0) {
+		netlink_setup_addr(&ip->addr, iface->ifindex, false, false);
+
+		list_del(&ip->head);
+		free(ip);
+	}
+
+	*ptr = NULL;
+}
+
+static bool leases_require_fr(struct interface *iface, struct odhcpd_ipaddr *addr,
+				uint32_t mask)
+{
+	struct dhcpv4_assignment *a = NULL;
+	struct odhcpd_ref_ip *fr_ip = NULL;
+
+	list_for_each_entry(a, &iface->dhcpv4_assignments, head) {
+		if ((a->accept_fr_nonce || iface->dhcpv4_forcereconf) &&
+		    !a->fr_ip &&
+		    ((a->addr & mask) == (addr->addr.in.s_addr & mask))) {
+			if (!fr_ip) {
+				fr_ip = calloc(1, sizeof(*fr_ip));
+				if (!fr_ip)
+					break;
+
+				list_add(&fr_ip->head, &iface->dhcpv4_fr_ips);
+				fr_ip->addr = *addr;
+			}
+			inc_ref_cnt_ip(&a->fr_ip, fr_ip);
 		}
+	}
+
+	return fr_ip ? true : false;
+}
+
+static void valid_until_cb(struct uloop_timeout *event)
+{
+	time_t now = odhcpd_time();
+	struct interface *iface;
+	list_for_each_entry(iface, &interfaces, head) {
+		if (iface->dhcpv4 != MODE_SERVER || iface->dhcpv4_assignments.next == NULL)
+			continue;
 
-		// Clean invalid assignments
 		struct dhcpv4_assignment *a, *n;
 		list_for_each_entry_safe(a, n, &iface->dhcpv4_assignments, head) {
-			if ((htonl(a->addr) & smask->sin_addr.s_addr) !=
-					(iface->dhcpv4_start.s_addr & smask->sin_addr.s_addr)) {
-				list_del(&a->head);
-				free(a);
-			}
+			if (!INFINITE_VALID(a->valid_until) && a->valid_until < now)
+				free_dhcpv4_assignment(a);
 		}
+	}
+	uloop_timeout_set(event, 1000);
+}
 
+static void handle_addrlist_change(struct interface *iface)
+{
+	struct odhcpd_ipaddr ip;
+	struct odhcpd_ref_ip *a;
+	struct dhcpv4_assignment *c;
+	uint32_t mask = iface->dhcpv4_mask.s_addr;
 
-		if (iface->dhcpv4_leasetime < 60)
-			iface->dhcpv4_leasetime = 43200;
+	memset(&ip, 0, sizeof(ip));
+	ip.addr.in = iface->dhcpv4_local;
+	ip.prefix = odhcpd_netmask2bitlen(false, &iface->dhcpv4_mask);
+	ip.broadcast = iface->dhcpv4_bcast;
 
-		iface->dhcpv4_event.uloop.fd = sock;
-		iface->dhcpv4_event.handle_dgram = handle_dhcpv4;
-		odhcpd_register(&iface->dhcpv4_event);
-	} else if (iface->dhcpv4_assignments.next) {
-		while (!list_empty(&iface->dhcpv4_assignments)) {
-			struct dhcpv4_assignment *a = list_first_entry(&iface->dhcpv4_assignments,
-					struct dhcpv4_assignment, head);
-			list_del(&a->head);
-			free(a->hostname);
-			free(a);
+	setup_dhcpv4_addresses(iface);
+
+	if ((ip.addr.in.s_addr & mask) ==
+	    (iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr))
+		return;
+
+	if (ip.addr.in.s_addr && !leases_require_fr(iface, &ip, mask))
+		return;
+
+	if (iface->dhcpv4_local.s_addr == INADDR_ANY || list_empty(&iface->dhcpv4_fr_ips))
+		return;
+
+	a = list_first_entry(&iface->dhcpv4_fr_ips, struct odhcpd_ref_ip, head);
+
+	if (netlink_setup_addr(&a->addr, iface->ifindex, false, true)) {
+		syslog(LOG_ERR, "Failed to add ip address");
+		return;
+	}
+
+	list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
+		if ((c->flags & OAF_BOUND) && c->fr_ip && !c->fr_cnt) {
+			if (c->accept_fr_nonce || iface->dhcpv4_forcereconf)
+				dhcpv4_fr_start(c);
+			else
+				dhcpv4_fr_stop(c);
 		}
+	}
+}
 
+static char *dhcpv4_msg_to_string(uint8_t reqmsg)
+{
+	switch (reqmsg) {
+	case (DHCPV4_MSG_DISCOVER):
+		return "DHCPV4_MSG_DISCOVER";
+	case (DHCPV4_MSG_OFFER):
+		return "DHCPV4_MSG_OFFER";
+	case (DHCPV4_MSG_REQUEST):
+		return "DHCPV4_MSG_REQUEST";
+	case (DHCPV4_MSG_DECLINE):
+		return "DHCPV4_MSG_DECLINE";
+	case (DHCPV4_MSG_ACK):
+		return "DHCPV4_MSG_ACK";
+	case (DHCPV4_MSG_NAK):
+		return "DHCPV4_MSG_NAK";
+	case (DHCPV4_MSG_RELEASE):
+		return "DHCPV4_MSG_RELEASE";
+	case (DHCPV4_MSG_INFORM):
+		return "DHCPV4_MSG_INFORM";
+	case (DHCPV4_MSG_FORCERENEW):
+		return "DHCPV4_MSG_FORCERENEW";
+	default:
+		return "UNKNOWN";
 	}
-	return 0;
 }
 
+static void free_dhcpv4_assignment(struct dhcpv4_assignment *a)
+{
+	if (a->head.next)
+		list_del(&a->head);
+
+	if (a->fr_ip)
+		dhcpv4_fr_stop(a);
+
+	free(a->hostname);
+	free(a);
+}
 
 static void dhcpv4_put(struct dhcpv4_message *msg, uint8_t **cookie,
 		uint8_t type, uint8_t len, const void *data)
 {
 	uint8_t *c = *cookie;
-	if (*cookie + 2 + len > (uint8_t*)&msg[1])
+	uint8_t *end = (uint8_t *)msg + sizeof(*msg);
+
+	if (*cookie + 2 + len > end)
 		return;
 
 	*c++ = type;
@@ -245,8 +506,124 @@ static void dhcpv4_put(struct dhcpv4_message *msg, uint8_t **cookie,
 	*cookie = c + len;
 }
 
+static void dhcpv4_fr_send(struct dhcpv4_assignment *a)
+{
+	struct dhcpv4_message fr_msg = {
+		.op = DHCPV4_BOOTREPLY,
+		.htype = 1,
+		.hlen = 6,
+		.hops = 0,
+		.secs = 0,
+		.flags = 0,
+		.ciaddr = {INADDR_ANY},
+		.yiaddr = {INADDR_ANY},
+		.siaddr = {INADDR_ANY},
+		.giaddr = {INADDR_ANY},
+		.chaddr = {0},
+		.sname = {0},
+		.file = {0},
+	};
+	struct dhcpv4_auth_forcerenew *auth_o, auth = {
+		.protocol = 3,
+		.algorithm = 1,
+		.rdm = 0,
+		.replay = {htonl(time(NULL)), htonl(++serial)},
+		.type = 2,
+		.key = {0},
+	};
+	struct interface *iface = a->iface;
+
+	odhcpd_urandom(&fr_msg.xid, sizeof(fr_msg.xid));
+	memcpy(fr_msg.chaddr, a->hwaddr, fr_msg.hlen);
+
+	fr_msg.options[0] = 0x63;
+	fr_msg.options[1] = 0x82;
+	fr_msg.options[2] = 0x53;
+	fr_msg.options[3] = 0x63;
+
+	uint8_t *cookie = &fr_msg.options[4];
+	uint8_t msg = DHCPV4_MSG_FORCERENEW;
+
+	dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
+	if (a->accept_fr_nonce) {
+		dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
+		auth_o = (struct dhcpv4_auth_forcerenew *)(cookie - sizeof(auth));
+		dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_END, 0, NULL);
+
+		md5_ctx_t md5;
+		uint8_t secretbytes[64];
+		memset(secretbytes, 0, sizeof(secretbytes));
+		memcpy(secretbytes, a->key, sizeof(a->key));
+
+		for (size_t i = 0; i < sizeof(secretbytes); ++i)
+			secretbytes[i] ^= 0x36;
+
+		md5_begin(&md5);
+		md5_hash(secretbytes, sizeof(secretbytes), &md5);
+		md5_hash(&fr_msg, sizeof(fr_msg), &md5);
+		md5_end(auth_o->key, &md5);
+
+		for (size_t i = 0; i < sizeof(secretbytes); ++i) {
+			secretbytes[i] ^= 0x36;
+			secretbytes[i] ^= 0x5c;
+		}
+
+		md5_begin(&md5);
+		md5_hash(secretbytes, sizeof(secretbytes), &md5);
+		md5_hash(auth_o->key, sizeof(auth_o->key), &md5);
+		md5_end(auth_o->key, &md5);
+	} else {
+		dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_SERVERID, 4,
+				&a->fr_ip->addr.addr.in.s_addr);
+		dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_END, 0, NULL);
+	}
+
+	struct sockaddr_in dest;
+	memset(&dest, 0, sizeof(dest));
+	dest.sin_family = AF_INET;
+	dest.sin_port = htons(DHCPV4_CLIENT_PORT);
+	dest.sin_addr.s_addr = a->addr;
+
+	syslog(LOG_WARNING, "sending %s to %02x:%02x:%02x:%02x:%02x:%02x - %s",
+			dhcpv4_msg_to_string(msg),
+			a->hwaddr[0], a->hwaddr[1], a->hwaddr[2],
+			a->hwaddr[3], a->hwaddr[4], a->hwaddr[5],
+			inet_ntoa(dest.sin_addr));
+
+	sendto(iface->dhcpv4_event.uloop.fd, &fr_msg, sizeof(fr_msg),
+			MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest));
+}
+
+static void dhcpv4_fr_timer(struct uloop_timeout *event)
+{
+	struct dhcpv4_assignment *a = container_of(event, struct dhcpv4_assignment, fr_timer);
+
+	if (a->fr_cnt > 0 && a->fr_cnt < 8) {
+		dhcpv4_fr_send(a);
+		uloop_timeout_set(&a->fr_timer, 1000 << a->fr_cnt);
+		a->fr_cnt++;
+	} else
+		dhcpv4_fr_stop(a);
+}
+
+static void dhcpv4_fr_start(struct dhcpv4_assignment *a)
+{
+	uloop_timeout_set(&a->fr_timer, 1000 << a->fr_cnt);
+	a->fr_timer.cb = dhcpv4_fr_timer;
+	a->fr_cnt++;
 
-// Simple DHCPv6-server for information requests
+	dhcpv4_fr_send(a);
+}
+
+static void dhcpv4_fr_stop(struct dhcpv4_assignment *a)
+{
+	uloop_timeout_cancel(&a->fr_timer);
+	decr_ref_cnt_ip(&a->fr_ip, a->iface);
+	a->fr_cnt = 0;
+	a->fr_timer.cb = NULL;
+}
+
+// Handler for DHCPv4 messages
 static void handle_dhcpv4(void *addr, void *data, size_t len,
 		struct interface *iface, _unused void *dest_addr)
 {
@@ -258,46 +635,27 @@ static void handle_dhcpv4(void *addr, void *data, size_t len,
 			req->op != DHCPV4_BOOTREQUEST || req->hlen != 6)
 		return;
 
-	int sock = iface->dhcpv4_event.uloop.fd;
-	struct sockaddr_in ifaddr;
-	struct sockaddr_in ifnetmask;
 
 	syslog(LOG_NOTICE, "Got DHCPv4 request");
 
-	struct ifreq ifreq;
-	memcpy(ifreq.ifr_name, iface->ifname, sizeof(ifreq.ifr_name));
-	if (ioctl(sock, SIOCGIFADDR, &ifreq)) {
-		syslog(LOG_WARNING, "DHCPv4 failed to detect address: %s", strerror(errno));
-		return;
-	}
-
-	memcpy(&ifaddr, &ifreq.ifr_addr, sizeof(ifaddr));
-	if (ioctl(sock, SIOCGIFNETMASK, &ifreq))
-		return;
-
-	memcpy(&ifnetmask, &ifreq.ifr_netmask, sizeof(ifnetmask));
-	uint32_t network = ifaddr.sin_addr.s_addr & ifnetmask.sin_addr.s_addr;
-
-	if ((iface->dhcpv4_start.s_addr & ifnetmask.sin_addr.s_addr) != network ||
-			(iface->dhcpv4_end.s_addr & ifnetmask.sin_addr.s_addr) != network) {
-		syslog(LOG_WARNING, "DHCPv4 range out of assigned network");
+	if (!iface->dhcpv4_start_ip.s_addr && !iface->dhcpv4_end_ip.s_addr) {
+		syslog(LOG_WARNING, "No DHCP range available on %s", iface->name);
 		return;
 	}
 
-	struct ifreq ifr = {.ifr_name = ""};
-	strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name));
+	int sock = iface->dhcpv4_event.uloop.fd;
 
 	struct dhcpv4_message reply = {
 		.op = DHCPV4_BOOTREPLY,
-		.htype = 1,
-		.hlen = 6,
+		.htype = req->htype,
+		.hlen = req->hlen,
 		.hops = 0,
 		.xid = req->xid,
 		.secs = 0,
 		.flags = req->flags,
 		.ciaddr = {INADDR_ANY},
 		.giaddr = req->giaddr,
-		.siaddr = ifaddr.sin_addr,
+		.siaddr = iface->dhcpv4_local,
 	};
 	memcpy(reply.chaddr, req->chaddr, sizeof(reply.chaddr));
 
@@ -310,23 +668,27 @@ static void handle_dhcpv4(void *addr, void *data, size_t len,
 	uint8_t reqmsg = DHCPV4_MSG_REQUEST;
 	uint8_t msg = DHCPV4_MSG_ACK;
 
-	struct in_addr reqaddr = {INADDR_ANY};
+	uint32_t reqaddr = INADDR_ANY;
+	uint32_t leasetime = 0;
+	size_t hostname_len = 0;
 	char hostname[256];
-	hostname[0] = 0;
+	bool accept_fr_nonce = false;
+	bool incl_fr_opt = false;
 
 	uint8_t *start = &req->options[4];
 	uint8_t *end = ((uint8_t*)data) + len;
 	struct dhcpv4_option *opt;
 	dhcpv4_for_each_option(start, end, opt) {
-		if (opt->type == DHCPV4_OPT_MESSAGE && opt->len == 1) {
+		if (opt->type == DHCPV4_OPT_MESSAGE && opt->len == 1)
 			reqmsg = opt->data[0];
-		} else if (opt->type == DHCPV4_OPT_HOSTNAME && opt->len > 0) {
-			memcpy(hostname, opt->data, opt->len);
-			hostname[opt->len] = 0;
-		} else if (opt->type == DHCPV4_OPT_IPADDRESS && opt->len == 4) {
+		else if (opt->type == DHCPV4_OPT_HOSTNAME && opt->len > 0) {
+			hostname_len = opt->len;
+			memcpy(hostname, opt->data, hostname_len);
+			hostname[hostname_len] = 0;
+		} else if (opt->type == DHCPV4_OPT_IPADDRESS && opt->len == 4)
 			memcpy(&reqaddr, opt->data, 4);
-		} else if (opt->type == DHCPV4_OPT_SERVERID && opt->len == 4) {
-			if (memcmp(opt->data, &ifaddr.sin_addr, 4))
+		else if (opt->type == DHCPV4_OPT_SERVERID && opt->len == 4) {
+			if (memcmp(opt->data, &iface->dhcpv4_local, 4))
 				return;
 		} else if (iface->filter_class && opt->type == DHCPV4_OPT_USER_CLASS) {
 			uint8_t *c = opt->data, *cend = &opt->data[opt->len];
@@ -335,6 +697,16 @@ static void handle_dhcpv4(void *addr, void *data, size_t len,
 				if (*c == elen && !memcmp(&c[1], iface->filter_class, elen))
 					return; // Ignore from homenet
 			}
+		} else if (opt->type == DHCPV4_OPT_LEASETIME && opt->len == 4)
+			memcpy(&leasetime, opt->data, 4);
+		else if (opt->type == DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE && opt->len > 0) {
+			for (uint8_t i = 0; i < opt->len; i++) {
+				if (opt->data[i] == 1) {
+					accept_fr_nonce = true;
+					break;
+				}
+			}
+
 		}
 	}
 
@@ -344,75 +716,129 @@ static void handle_dhcpv4(void *addr, void *data, size_t len,
 		return;
 
 	struct dhcpv4_assignment *lease = NULL;
+	uint32_t serverid = iface->dhcpv4_local.s_addr;
+	uint32_t fr_serverid = INADDR_ANY;
+
 	if (reqmsg != DHCPV4_MSG_INFORM)
-		lease = dhcpv4_lease(iface, reqmsg, req->chaddr, reqaddr, hostname);
+		lease = dhcpv4_lease(iface, reqmsg, req->chaddr, reqaddr,
+					&leasetime, hostname, hostname_len,
+					accept_fr_nonce, &incl_fr_opt, &fr_serverid);
 
 	if (!lease) {
 		if (reqmsg == DHCPV4_MSG_REQUEST)
 			msg = DHCPV4_MSG_NAK;
 		else if (reqmsg == DHCPV4_MSG_DISCOVER)
 			return;
-	} else if (reqmsg == DHCPV4_MSG_DISCOVER) {
+	} else if (reqmsg == DHCPV4_MSG_DISCOVER)
 		msg = DHCPV4_MSG_OFFER;
-	} else if (reqmsg == DHCPV4_MSG_REQUEST && reqaddr.s_addr &&
-			reqaddr.s_addr != htonl(lease->addr)) {
+	else if (reqmsg == DHCPV4_MSG_REQUEST &&
+			((reqaddr && reqaddr != lease->addr) ||
+			 (req->ciaddr.s_addr && req->ciaddr.s_addr != lease->addr))) {
 		msg = DHCPV4_MSG_NAK;
 		/*
 		 * DHCP client requested an IP which we can't offer to him. Probably the
-		 * client changed the network. The reply type is set to DHCPV4_MSG_NAK,
-		 * because the client should not use that IP.
+		 * client changed the network or the network has been changed. The reply
+		 * type is set to DHCPV4_MSG_NAK, because the client should not use that IP.
 		 *
 		 * For modern devices we build an answer that includes a valid IP, like
 		 * a DHCPV4_MSG_ACK. The client will use that IP and doesn't need to
 		 * perform additional DHCP round trips.
 		 *
 		 */
+
+		/*
+		 *
+		 * Buggy clients do serverid checking in nack messages; therefore set the
+		 * serverid in nack messages triggered by a previous force renew equal to
+		 * the server id in use at that time by the server
+		 *
+		 */
+		if (fr_serverid)
+			serverid = fr_serverid;
+
+		if (req->ciaddr.s_addr &&
+				((iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr) !=
+				 (req->ciaddr.s_addr & iface->dhcpv4_mask.s_addr)))
+			req->ciaddr.s_addr = INADDR_ANY;
 	}
 
-	syslog(LOG_WARNING, "received %s from %x:%x:%x:%x:%x:%x",
+	syslog(LOG_WARNING, "received %s from %02x:%02x:%02x:%02x:%02x:%02x",
 			dhcpv4_msg_to_string(reqmsg),
 			req->chaddr[0],req->chaddr[1],req->chaddr[2],
 			req->chaddr[3],req->chaddr[4],req->chaddr[5]);
 
+#ifdef WITH_UBUS
+	if (reqmsg == DHCPV4_MSG_RELEASE)
+		ubus_bcast_dhcp_event("dhcp.release", req->chaddr, req->hlen,
+					&req->ciaddr, hostname, iface->ifname);
+#endif
 	if (reqmsg == DHCPV4_MSG_DECLINE || reqmsg == DHCPV4_MSG_RELEASE)
 		return;
 
 	dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
-	dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SERVERID, 4, &ifaddr.sin_addr);
+	dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SERVERID, 4, &serverid);
 
 	if (lease) {
-		reply.yiaddr.s_addr = htonl(lease->addr);
+		uint32_t val;
+
+		reply.yiaddr.s_addr = lease->addr;
 
-		uint32_t val = htonl(iface->dhcpv4_leasetime);
+		val = htonl(leasetime);
 		dhcpv4_put(&reply, &cookie, DHCPV4_OPT_LEASETIME, 4, &val);
 
-		val = htonl(500 * iface->dhcpv4_leasetime / 1000);
-		dhcpv4_put(&reply, &cookie, DHCPV4_OPT_RENEW, 4, &val);
+		if (leasetime != UINT32_MAX) {
+			val = htonl(500 * leasetime / 1000);
+			dhcpv4_put(&reply, &cookie, DHCPV4_OPT_RENEW, 4, &val);
 
-		val = htonl(875 * iface->dhcpv4_leasetime / 1000);
-		dhcpv4_put(&reply, &cookie, DHCPV4_OPT_REBIND, 4, &val);
+			val = htonl(875 * leasetime / 1000);
+			dhcpv4_put(&reply, &cookie, DHCPV4_OPT_REBIND, 4, &val);
+		}
 
-		dhcpv4_put(&reply, &cookie, DHCPV4_OPT_NETMASK, 4, &ifnetmask.sin_addr);
+		dhcpv4_put(&reply, &cookie, DHCPV4_OPT_NETMASK, 4,
+				&iface->dhcpv4_mask.s_addr);
 
-		if (lease->hostname[0])
+		if (lease->hostname)
 			dhcpv4_put(&reply, &cookie, DHCPV4_OPT_HOSTNAME,
 					strlen(lease->hostname), lease->hostname);
 
-		if (!ioctl(sock, SIOCGIFBRDADDR, &ifr)) {
-			struct sockaddr_in *ina = (struct sockaddr_in*)&ifr.ifr_broadaddr;
-			dhcpv4_put(&reply, &cookie, DHCPV4_OPT_BROADCAST, 4, &ina->sin_addr);
+		if (iface->dhcpv4_bcast.s_addr != INADDR_ANY)
+			dhcpv4_put(&reply, &cookie, DHCPV4_OPT_BROADCAST, 4, &iface->dhcpv4_bcast);
+
+		if (incl_fr_opt) {
+			if (reqmsg == DHCPV4_MSG_REQUEST) {
+				struct dhcpv4_auth_forcerenew auth = {
+					.protocol = 3,
+					.algorithm = 1,
+					.rdm = 0,
+					.replay = {htonl(time(NULL)), htonl(++serial)},
+					.type = 1,
+					.key = {0},
+				};
+
+				memcpy(auth.key, lease->key, sizeof(auth.key));
+				dhcpv4_put(&reply, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
+			} else {
+				uint8_t one = 1;
+				dhcpv4_put(&reply, &cookie, DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE,
+					sizeof(one), &one);
+			}
 		}
 	}
 
+	struct ifreq ifr;
+
+	memset(&ifr, 0, sizeof(ifr));
+	strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name) - 1);
+
 	if (!ioctl(sock, SIOCGIFMTU, &ifr)) {
 		uint16_t mtu = htons(ifr.ifr_mtu);
 		dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MTU, 2, &mtu);
 	}
 
-	if (iface->search && iface->search_len <= 255) {
+	if (iface->search && iface->search_len <= 255)
 		dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
 				iface->search_len, iface->search);
-	} else if (!res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
+	else if (!res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
 		uint8_t search_buf[256];
 		int len = dn_comp(_res.dnsrch[0], search_buf,
 						sizeof(search_buf), NULL, NULL);
@@ -422,14 +848,14 @@ static void handle_dhcpv4(void *addr, void *data, size_t len,
 	}
 
 	if (iface->dhcpv4_router_cnt == 0)
-		dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER, 4, &ifaddr.sin_addr);
+		dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER, 4, &iface->dhcpv4_local);
 	else
 		dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER,
 				4 * iface->dhcpv4_router_cnt, iface->dhcpv4_router);
 
 
 	if (iface->dhcpv4_dns_cnt == 0)
-		dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER, 4, &ifaddr.sin_addr);
+		dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER, 4, &iface->dhcpv4_local);
 	else
 		dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER,
 				4 * iface->dhcpv4_dns_cnt, iface->dhcpv4_dns);
@@ -479,147 +905,199 @@ static void handle_dhcpv4(void *addr, void *data, size_t len,
 		ioctl(sock, SIOCSARP, &arp);
 	}
 
-	if (dest.sin_addr.s_addr == INADDR_BROADCAST) {
-		/*
-		 * reply goes to IP broadcast -> MAC broadcast
-		 */
+	if (dest.sin_addr.s_addr == INADDR_BROADCAST)
+		/* reply goes to IP broadcast -> MAC broadcast */
 		syslog(LOG_WARNING, "sending %s to ff:ff:ff:ff:ff:ff - %s",
 				dhcpv4_msg_to_string(msg),
 				inet_ntoa(dest.sin_addr));
-	} else {
+	else
 		/*
 		 * reply is send directly to IP,
 		 * MAC is assumed to be the same as the request
 		 */
-		syslog(LOG_WARNING, "sending %s to %x:%x:%x:%x:%x:%x - %s",
+		syslog(LOG_WARNING, "sending %s to %02x:%02x:%02x:%02x:%02x:%02x - %s",
 				dhcpv4_msg_to_string(msg),
 				req->chaddr[0],req->chaddr[1],req->chaddr[2],
 				req->chaddr[3],req->chaddr[4],req->chaddr[5],
 				inet_ntoa(dest.sin_addr));
-	}
 
 	sendto(sock, &reply, sizeof(reply), MSG_DONTWAIT,
 			(struct sockaddr*)&dest, sizeof(dest));
-}
 
+#ifdef WITH_UBUS
+	if (msg == DHCPV4_MSG_ACK)
+		ubus_bcast_dhcp_event("dhcp.ack", req->chaddr, req->hlen, &reply.yiaddr,
+					hostname, iface->ifname);
+#endif
+}
 
 static bool dhcpv4_assign(struct interface *iface,
 		struct dhcpv4_assignment *assign, uint32_t raddr)
 {
-	const unsigned tries = 100;
-	uint32_t start = ntohl(iface->dhcpv4_start.s_addr);
-	uint32_t end = ntohl(iface->dhcpv4_end.s_addr);
+	uint32_t start = ntohl(iface->dhcpv4_start_ip.s_addr);
+	uint32_t end = ntohl(iface->dhcpv4_end_ip.s_addr);
 	uint32_t count = end - start + 1;
 
+	// try to assign the IP the client asked for
+	if (start <= ntohl(raddr) && ntohl(raddr) <= end &&
+			!find_assignment_by_addr(iface, raddr)) {
+		assign->addr = raddr;
+		syslog(LOG_INFO, "assigning the IP the client asked for: %u.%u.%u.%u",
+				((uint8_t *)&assign->addr)[0],
+				((uint8_t *)&assign->addr)[1],
+				((uint8_t *)&assign->addr)[2],
+				((uint8_t *)&assign->addr)[3]);
+		return true;
+	}
+
 	// Seed RNG with checksum of hwaddress
 	uint32_t seed = 0;
-	for (size_t i = 0; i < sizeof(assign->hwaddr); ++i)
-		seed += assign->hwaddr[i];
+	for (size_t i = 0; i < sizeof(assign->hwaddr); ++i) {
+		// Knuth's multiplicative method
+		uint8_t o = assign->hwaddr[i];
+		seed += (o*2654435761) % UINT32_MAX;
+	}
+
 	srand(seed);
 
-	// Try to assign up to 100x
-	for (unsigned i = 0; i < tries; ++i) {
-		uint32_t try = (((uint32_t)rand()) % count) + start;
-		if (i == 0 && raddr >= start && raddr <= end)
-			try = raddr;
-		else if (i == tries - 1)
-			try = start;
-
-		if (list_empty(&iface->dhcpv4_assignments)) {
-			assign->addr = try;
-			list_add(&assign->head, &iface->dhcpv4_assignments);
-			return true;
-		}
+	uint32_t try = (((uint32_t)rand()) % count) + start;
 
-		struct dhcpv4_assignment *c;
-		list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
-			if (c->addr > try) {
-				assign->addr = try;
-				list_add_tail(&assign->head, &c->head);
-				return true;
-			} else if (c->addr == try) {
-				if (i < tries - 1)
-					break;
-				else
-					++try;
-			}
+	if (list_empty(&iface->dhcpv4_assignments)) {
+		assign->addr = htonl(try);
+		syslog(LOG_INFO, "assigning mapped IP (empty list): %u.%u.%u.%u",
+				((uint8_t *)&assign->addr)[0],
+				((uint8_t *)&assign->addr)[1],
+				((uint8_t *)&assign->addr)[2],
+				((uint8_t *)&assign->addr)[3]);
+		return true;
+	}
+
+	for (uint32_t i = 0; i < count; ++i) {
+		if (!find_assignment_by_addr(iface, htonl(try))) {
+			/* test was successful: IP address is not assigned, assign it */
+			assign->addr = htonl(try);
+			syslog(LOG_DEBUG, "assigning mapped IP: %u.%u.%u.%u (try %u of %u)",
+					((uint8_t *)&assign->addr)[0],
+					((uint8_t *)&assign->addr)[1],
+					((uint8_t *)&assign->addr)[2],
+					((uint8_t *)&assign->addr)[3],
+					i, count);
+			return true;
 		}
+		try = (((try - start) + 1) % count) + start;
 	}
 
+	syslog(LOG_WARNING, "can't assign any IP address -> address space is full");
 	return false;
 }
 
 
 static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
-		enum dhcpv4_msg msg, const uint8_t *mac, struct in_addr reqaddr,
-		const char *hostname)
+		enum dhcpv4_msg msg, const uint8_t *mac, const uint32_t reqaddr,
+		uint32_t *leasetime, const char *hostname, const size_t hostname_len,
+		const bool accept_fr_nonce, bool *incl_fr_opt, uint32_t *fr_serverid)
 {
+	struct dhcpv4_assignment *a = find_assignment_by_hwaddr(iface, mac);
 	struct dhcpv4_assignment *lease = NULL;
-	uint32_t raddr = ntohl(reqaddr.s_addr);
 	time_t now = odhcpd_time();
 
-	struct dhcpv4_assignment *c, *n, *a = NULL;
-	list_for_each_entry_safe(c, n, &iface->dhcpv4_assignments, head) {
-		if (!memcmp(c->hwaddr, mac, 6)) {
-			a = c;
-			if (c->addr == raddr)
-				break;
-		} else if (c->valid_until < now) {
-			list_del(&c->head);
-			free(c);
-		}
+	if (a && (a->flags & OAF_BOUND) && a->fr_ip) {
+		*fr_serverid = a->fr_ip->addr.addr.in.s_addr;
+		dhcpv4_fr_stop(a);
 	}
 
 	if (msg == DHCPV4_MSG_DISCOVER || msg == DHCPV4_MSG_REQUEST) {
 		bool assigned = !!a;
-		size_t hostlen = strlen(hostname) + 1;
 
-		if (!a && !iface->no_dynamic_dhcp) { // Create new binding
-			a = calloc(1, sizeof(*a) + hostlen);
-			if (!a) {
-				syslog(LOG_ERR, "Failed to calloc binding on interface %s", iface->ifname);
-				return NULL;
+		if (!a) {
+			if (!iface->no_dynamic_dhcp) {
+				/* Create new binding */
+				a = calloc(1, sizeof(*a));
+				if (!a) {
+					syslog(LOG_ERR, "Failed to calloc binding on interface %s",
+							iface->ifname);
+					return NULL;
+				}
+				memcpy(a->hwaddr, mac, sizeof(a->hwaddr));
+				/* Don't consider new assignment as infinite */
+				a->valid_until = now;
+
+				assigned = dhcpv4_assign(iface, a, reqaddr);
+				if (assigned) {
+					a->iface = iface;
+					list_add(&a->head, &iface->dhcpv4_assignments);
+				}
 			}
-			memcpy(a->hwaddr, mac, sizeof(a->hwaddr));
-			memcpy(a->hostname, hostname, hostlen);
+		} else if ((a->addr & iface->dhcpv4_mask.s_addr) !=
+				(iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr)) {
+			list_del(&a->head);
 
-			assigned = dhcpv4_assign(iface, a, raddr);
+			assigned = dhcpv4_assign(iface, a, reqaddr);
+			if (assigned)
+				list_add(&a->head, &iface->dhcpv4_assignments);
 		}
 
-		if (assigned && !a->hostname[0] && hostname) {
-			a = realloc(a, sizeof(*a) + hostlen);
-			if (!a) {
-				syslog(LOG_ERR, "Failed to realloc binding on interface %s", iface->ifname);
-				return NULL;
-			}
-			memcpy(a->hostname, hostname, hostlen);
+		if (assigned) {
+			uint32_t my_leasetime;
+
+			if (a->leasetime)
+				my_leasetime = a->leasetime;
+			else
+				my_leasetime = iface->dhcpv4_leasetime;
+
+			if ((*leasetime == 0) || (my_leasetime < *leasetime))
+				*leasetime = my_leasetime;
+
+			if (msg == DHCPV4_MSG_DISCOVER) {
+				a->flags &= ~OAF_BOUND;
+
+				*incl_fr_opt = accept_fr_nonce;
+				if (!(a->flags & OAF_STATIC))
+					a->valid_until = now;
+			} else {
+				if (hostname_len > 0) {
+					a->hostname = realloc(a->hostname, hostname_len + 1);
+					if (a->hostname) {
+						memcpy(a->hostname, hostname, hostname_len);
+						a->hostname[hostname_len] = 0;
+					}
+				}
 
-			// Fixup list
-			a->head.next->prev = &a->head;
-			a->head.prev->next = &a->head;
-		}
+				if (!(a->flags & OAF_BOUND)) {
+					a->accept_fr_nonce = accept_fr_nonce;
+					*incl_fr_opt = accept_fr_nonce;
+					odhcpd_urandom(a->key, sizeof(a->key));
+					a->flags |= OAF_BOUND;
+				} else
+					*incl_fr_opt = false;
 
-		// Was only a solicitation: mark binding for removal
-		if (assigned && a->valid_until < now) {
-			a->valid_until = (msg == DHCPV4_MSG_DISCOVER) ? 0 :
-					(now + iface->dhcpv4_leasetime);
-		} else if (!assigned && a) { // Cleanup failed assignment
-			free(a);
+				if (!(a->flags & OAF_STATIC))
+					a->valid_until = ((*leasetime == UINT32_MAX) ? 0 : (time_t)(now + *leasetime));
+			}
+		} else if (!assigned && a) {
+			/* Cleanup failed assignment */
+			free_dhcpv4_assignment(a);
 			a = NULL;
 		}
 
 		if (assigned && a)
 			lease = a;
-	} else if (msg == DHCPV4_MSG_RELEASE) {
-		if (a && a->valid_until != LONG_MAX)
-			a->valid_until = 0;
-	} else if (msg == DHCPV4_MSG_DECLINE && a->valid_until != LONG_MAX) {
-		memset(a->hwaddr, 0, sizeof(a->hwaddr));
-		a->valid_until = now + 3600; // Block address for 1h
+	} else if (msg == DHCPV4_MSG_RELEASE && a) {
+		a->flags &= ~OAF_BOUND;
+
+		if (!(a->flags & OAF_STATIC))
+			a->valid_until = now - 1;
+
+	} else if (msg == DHCPV4_MSG_DECLINE && a) {
+		a->flags &= ~OAF_BOUND;
+
+		if (!(a->flags & OAF_STATIC)) {
+			memset(a->hwaddr, 0, sizeof(a->hwaddr));
+			a->valid_until = now + 3600; /* Block address for 1h */
+		}
 	}
 
 	dhcpv6_write_statefile();
 
 	return lease;
 }
-