2 * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
3 * Copyright (C) 2016 Hans Dedecker <dedeckeh@gmail.com>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License v2 as published by
7 * the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
26 #include <net/if_arp.h>
27 #include <netinet/ip.h>
28 #include <sys/ioctl.h>
29 #include <sys/timerfd.h>
30 #include <arpa/inet.h>
32 #include <libubox/md5.h>
38 static void dhcpv4_netevent_cb(unsigned long event, struct netevent_handler_info *info);
39 static int setup_dhcpv4_addresses(struct interface *iface);
40 static void update_static_assignments(struct interface *iface);
41 static bool addr_is_fr_ip(struct interface *iface, struct in_addr *addr);
42 static void valid_until_cb(struct uloop_timeout *event);
43 static void handle_addrlist_change(struct interface *iface);
44 static void free_dhcpv4_assignment(struct dhcpv4_assignment *a);
45 static void dhcpv4_fr_start(struct dhcpv4_assignment *a);
46 static void dhcpv4_fr_rand_delay(struct dhcpv4_assignment *a);
47 static void dhcpv4_fr_stop(struct dhcpv4_assignment *a);
48 static void handle_dhcpv4(void *addr, void *data, size_t len,
49 struct interface *iface, void *dest_addr);
50 static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
51 enum dhcpv4_msg msg, const uint8_t *mac, const uint32_t reqaddr,
52 uint32_t *leasetime, const char *hostname, const size_t hostname_len,
53 const bool accept_fr_nonce, bool *incl_fr_opt, uint32_t *fr_serverid);
55 static struct netevent_handler dhcpv4_netevent_handler = { .cb = dhcpv4_netevent_cb, };
56 static struct uloop_timeout valid_until_timeout = {.cb = valid_until_cb};
57 static uint32_t serial = 0;
59 struct odhcpd_ref_ip {
60 struct list_head head;
62 struct odhcpd_ipaddr addr;
65 /* Create socket and register events */
68 uloop_timeout_set(&valid_until_timeout, 1000);
69 netlink_add_netevent_handler(&dhcpv4_netevent_handler);
74 int dhcpv4_setup_interface(struct interface *iface, bool enable)
78 if (iface->dhcpv4_event.uloop.fd > 0) {
79 uloop_fd_delete(&iface->dhcpv4_event.uloop);
80 close(iface->dhcpv4_event.uloop.fd);
81 iface->dhcpv4_event.uloop.fd = -1;
84 if (iface->dhcpv4 && enable) {
85 struct sockaddr_in bind_addr = {AF_INET, htons(DHCPV4_SERVER_PORT),
89 if (!iface->dhcpv4_assignments.next)
90 INIT_LIST_HEAD(&iface->dhcpv4_assignments);
92 if (!iface->dhcpv4_fr_ips.next)
93 INIT_LIST_HEAD(&iface->dhcpv4_fr_ips);
95 iface->dhcpv4_event.uloop.fd = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
96 if (iface->dhcpv4_event.uloop.fd < 0) {
97 syslog(LOG_ERR, "socket(AF_INET): %m");
102 /* Basic IPv4 configuration */
103 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_REUSEADDR,
104 &val, sizeof(val)) < 0) {
105 syslog(LOG_ERR, "setsockopt(SO_REUSEADDR): %m");
110 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_BROADCAST,
111 &val, sizeof(val)) < 0) {
112 syslog(LOG_ERR, "setsockopt(SO_BROADCAST): %m");
117 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_PKTINFO,
118 &val, sizeof(val)) < 0) {
119 syslog(LOG_ERR, "setsockopt(IP_PKTINFO): %m");
124 val = IPTOS_PREC_INTERNETCONTROL;
125 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_TOS,
126 &val, sizeof(val)) < 0) {
127 syslog(LOG_ERR, "setsockopt(IP_TOS): %m");
132 val = IP_PMTUDISC_DONT;
133 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_MTU_DISCOVER,
134 &val, sizeof(val)) < 0) {
135 syslog(LOG_ERR, "setsockopt(IP_MTU_DISCOVER): %m");
140 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_BINDTODEVICE,
141 iface->ifname, strlen(iface->ifname)) < 0) {
142 syslog(LOG_ERR, "setsockopt(SO_BINDTODEVICE): %m");
147 if (bind(iface->dhcpv4_event.uloop.fd, (struct sockaddr*)&bind_addr,
148 sizeof(bind_addr)) < 0) {
149 syslog(LOG_ERR, "bind(): %m");
154 if (setup_dhcpv4_addresses(iface) < 0) {
159 iface->dhcpv4_event.handle_dgram = handle_dhcpv4;
160 odhcpd_register(&iface->dhcpv4_event);
162 update_static_assignments(iface);
163 } else if (iface->dhcpv4_assignments.next) {
164 while (!list_empty(&iface->dhcpv4_assignments))
165 free_dhcpv4_assignment(list_first_entry(&iface->dhcpv4_assignments,
166 struct dhcpv4_assignment, head));
170 if (ret < 0 && iface->dhcpv4_event.uloop.fd > 0) {
171 close(iface->dhcpv4_event.uloop.fd);
172 iface->dhcpv4_event.uloop.fd = -1;
179 static void dhcpv4_netevent_cb(unsigned long event, struct netevent_handler_info *info)
181 struct interface *iface = info->iface;
183 if (!iface || iface->dhcpv4 == MODE_DISABLED)
187 case NETEV_IFINDEX_CHANGE:
188 dhcpv4_setup_interface(iface, true);
190 case NETEV_ADDRLIST_CHANGE:
191 handle_addrlist_change(iface);
198 static struct dhcpv4_assignment *find_assignment_by_hwaddr(struct interface *iface, const uint8_t *hwaddr)
200 struct dhcpv4_assignment *a;
202 list_for_each_entry(a, &iface->dhcpv4_assignments, head)
203 if (!memcmp(a->hwaddr, hwaddr, 6))
209 static struct dhcpv4_assignment *find_assignment_by_addr(struct interface *iface, const uint32_t addr)
211 struct dhcpv4_assignment *a;
213 list_for_each_entry(a, &iface->dhcpv4_assignments, head)
220 static int setup_dhcpv4_addresses(struct interface *iface)
222 iface->dhcpv4_start_ip.s_addr = INADDR_ANY;
223 iface->dhcpv4_end_ip.s_addr = INADDR_ANY;
224 iface->dhcpv4_local.s_addr = INADDR_ANY;
225 iface->dhcpv4_bcast.s_addr = INADDR_ANY;
226 iface->dhcpv4_mask.s_addr = INADDR_ANY;
229 if (iface->dhcpv4_start.s_addr & htonl(0xffff0000) ||
230 iface->dhcpv4_end.s_addr & htonl(0xffff0000) ||
231 ntohl(iface->dhcpv4_start.s_addr) > ntohl(iface->dhcpv4_end.s_addr)) {
232 syslog(LOG_ERR, "Invalid DHCP range for %s", iface->name);
236 if (!iface->addr4_len) {
237 syslog(LOG_WARNING, "No network(s) available on %s", iface->name);
241 uint32_t start = ntohl(iface->dhcpv4_start.s_addr);
242 uint32_t end = ntohl(iface->dhcpv4_end.s_addr);
244 for (size_t i = 0; i < iface->addr4_len && start && end; i++) {
245 struct in_addr *addr = &iface->addr4[i].addr.in;
248 if (addr_is_fr_ip(iface, addr))
251 odhcpd_bitlen2netmask(false, iface->addr4[i].prefix, &mask);
252 if ((start & ntohl(~mask.s_addr)) == start &&
253 (end & ntohl(~mask.s_addr)) == end) {
254 iface->dhcpv4_start_ip.s_addr = htonl(start) |
255 (addr->s_addr & mask.s_addr);
256 iface->dhcpv4_end_ip.s_addr = htonl(end) |
257 (addr->s_addr & mask.s_addr);
258 iface->dhcpv4_local = *addr;
259 iface->dhcpv4_bcast = iface->addr4[i].broadcast;
260 iface->dhcpv4_mask = mask;
265 /* Don't allocate IP range for subnets bigger than 28 */
266 if (iface->addr4[0].prefix > 28) {
267 syslog(LOG_WARNING, "Auto allocation of DHCP range fails on %s", iface->name);
271 iface->dhcpv4_local = iface->addr4[0].addr.in;
272 iface->dhcpv4_bcast = iface->addr4[0].broadcast;
273 odhcpd_bitlen2netmask(false, iface->addr4[0].prefix, &iface->dhcpv4_mask);
274 end = start = iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr;
276 /* Auto allocate ranges */
277 if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffff00) {
278 iface->dhcpv4_start_ip.s_addr = start | htonl(100);
279 iface->dhcpv4_end_ip.s_addr = end | htonl(250);
280 } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffc0) {
281 iface->dhcpv4_start_ip.s_addr = start | htonl(10);
282 iface->dhcpv4_end_ip.s_addr = end | htonl(60);
283 } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffe0) {
284 iface->dhcpv4_start_ip.s_addr = start | htonl(10);
285 iface->dhcpv4_end_ip.s_addr = end | htonl(30);
287 iface->dhcpv4_start_ip.s_addr = start | htonl(3);
288 iface->dhcpv4_end_ip.s_addr = end | htonl(12);
294 static void update_static_assignments(struct interface *iface)
296 struct dhcpv4_assignment *a, *c;
298 /* Cleanup static entries not belonging to the network */
299 list_for_each_entry_safe(a, c, &iface->dhcpv4_assignments, head) {
300 if ((a->flags & OAF_STATIC) &&
301 ((a->addr & iface->dhcpv4_mask.s_addr) !=
302 (iface->dhcpv4_start.s_addr & iface->dhcpv4_mask.s_addr)))
303 free_dhcpv4_assignment(a);
306 /* Parse static entries */
308 list_for_each_entry(lease, &leases, head) {
309 if ((iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr) !=
310 (lease->ipaddr.s_addr & iface->dhcpv4_mask.s_addr)) {
314 a = find_assignment_by_hwaddr(iface, lease->mac.ether_addr_octet);
317 /* Check if there's an assignment with the specified IP address */
318 if (find_assignment_by_addr(iface, lease->ipaddr.s_addr))
321 /* Construct entry */
322 a = calloc(1, sizeof(*a));
324 syslog(LOG_ERR, "Calloc failed for static lease on %s", iface->name);
327 memcpy(a->hwaddr, lease->mac.ether_addr_octet, sizeof(a->hwaddr));
330 a->leasetime = lease->dhcpv4_leasetime;
332 a->addr = lease->ipaddr.s_addr;
333 /* Static assignment */
334 a->flags |= OAF_STATIC;
338 if (lease->hostname[0]) {
340 a->hostname = strdup(lease->hostname);
343 /* Assign to all interfaces */
344 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
345 if (ntohl(c->addr) > ntohl(a->addr)) {
346 list_add_tail(&a->head, &c->head);
351 if (&c->head == &iface->dhcpv4_assignments)
352 list_add(&a->head, &iface->dhcpv4_assignments);
356 static void inc_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct odhcpd_ref_ip *ip)
362 static void decr_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct interface *iface)
364 struct odhcpd_ref_ip *ip = *ptr;
366 if (--ip->ref_cnt == 0) {
367 netlink_setup_addr(&ip->addr, iface->ifindex, false, false);
376 static bool addr_is_fr_ip(struct interface *iface, struct in_addr *addr)
378 struct odhcpd_ref_ip *p;
380 list_for_each_entry(p, &iface->dhcpv4_fr_ips, head) {
381 if (addr->s_addr == p->addr.addr.in.s_addr)
388 static bool leases_require_fr(struct interface *iface, struct odhcpd_ipaddr *addr,
391 struct dhcpv4_assignment *a = NULL;
392 struct odhcpd_ref_ip *fr_ip = NULL;
394 list_for_each_entry(a, &iface->dhcpv4_assignments, head) {
395 if ((a->accept_fr_nonce || iface->dhcpv4_forcereconf) &&
397 ((a->addr & mask) == (addr->addr.in.s_addr & mask))) {
399 fr_ip = calloc(1, sizeof(*fr_ip));
403 list_add(&fr_ip->head, &iface->dhcpv4_fr_ips);
406 inc_ref_cnt_ip(&a->fr_ip, fr_ip);
410 return fr_ip ? true : false;
413 static void valid_until_cb(struct uloop_timeout *event)
415 time_t now = odhcpd_time();
416 struct interface *iface;
417 list_for_each_entry(iface, &interfaces, head) {
418 if (iface->dhcpv4 != MODE_SERVER || iface->dhcpv4_assignments.next == NULL)
421 struct dhcpv4_assignment *a, *n;
422 list_for_each_entry_safe(a, n, &iface->dhcpv4_assignments, head) {
423 if (!INFINITE_VALID(a->valid_until) && a->valid_until < now)
424 free_dhcpv4_assignment(a);
427 uloop_timeout_set(event, 1000);
430 static void handle_addrlist_change(struct interface *iface)
432 struct odhcpd_ipaddr ip;
433 struct odhcpd_ref_ip *a;
434 struct dhcpv4_assignment *c;
435 uint32_t mask = iface->dhcpv4_mask.s_addr;
437 memset(&ip, 0, sizeof(ip));
438 ip.addr.in = iface->dhcpv4_local;
439 ip.prefix = odhcpd_netmask2bitlen(false, &iface->dhcpv4_mask);
440 ip.broadcast = iface->dhcpv4_bcast;
442 setup_dhcpv4_addresses(iface);
444 if ((ip.addr.in.s_addr & mask) ==
445 (iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr))
448 if (ip.addr.in.s_addr && !leases_require_fr(iface, &ip, mask))
451 if (iface->dhcpv4_local.s_addr == INADDR_ANY || list_empty(&iface->dhcpv4_fr_ips))
454 a = list_first_entry(&iface->dhcpv4_fr_ips, struct odhcpd_ref_ip, head);
456 if (netlink_setup_addr(&a->addr, iface->ifindex, false, true)) {
457 syslog(LOG_ERR, "Failed to add ip address on %s", iface->name);
461 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
462 if ((c->flags & OAF_BOUND) && c->fr_ip && !c->fr_cnt) {
463 if (c->accept_fr_nonce || iface->dhcpv4_forcereconf)
464 dhcpv4_fr_rand_delay(c);
471 static char *dhcpv4_msg_to_string(uint8_t reqmsg)
474 case (DHCPV4_MSG_DISCOVER):
475 return "DHCPV4_MSG_DISCOVER";
476 case (DHCPV4_MSG_OFFER):
477 return "DHCPV4_MSG_OFFER";
478 case (DHCPV4_MSG_REQUEST):
479 return "DHCPV4_MSG_REQUEST";
480 case (DHCPV4_MSG_DECLINE):
481 return "DHCPV4_MSG_DECLINE";
482 case (DHCPV4_MSG_ACK):
483 return "DHCPV4_MSG_ACK";
484 case (DHCPV4_MSG_NAK):
485 return "DHCPV4_MSG_NAK";
486 case (DHCPV4_MSG_RELEASE):
487 return "DHCPV4_MSG_RELEASE";
488 case (DHCPV4_MSG_INFORM):
489 return "DHCPV4_MSG_INFORM";
490 case (DHCPV4_MSG_FORCERENEW):
491 return "DHCPV4_MSG_FORCERENEW";
497 static void free_dhcpv4_assignment(struct dhcpv4_assignment *a)
509 static void dhcpv4_put(struct dhcpv4_message *msg, uint8_t **cookie,
510 uint8_t type, uint8_t len, const void *data)
512 uint8_t *c = *cookie;
513 uint8_t *end = (uint8_t *)msg + sizeof(*msg);
515 if (*cookie + 2 + len > end)
520 memcpy(c, data, len);
525 static void dhcpv4_fr_send(struct dhcpv4_assignment *a)
527 struct dhcpv4_message fr_msg = {
528 .op = DHCPV4_BOOTREPLY,
534 .ciaddr = {INADDR_ANY},
535 .yiaddr = {INADDR_ANY},
536 .siaddr = {INADDR_ANY},
537 .giaddr = {INADDR_ANY},
542 struct dhcpv4_auth_forcerenew *auth_o, auth = {
546 .replay = {htonl(time(NULL)), htonl(++serial)},
550 struct interface *iface = a->iface;
552 odhcpd_urandom(&fr_msg.xid, sizeof(fr_msg.xid));
553 memcpy(fr_msg.chaddr, a->hwaddr, fr_msg.hlen);
555 fr_msg.options[0] = 0x63;
556 fr_msg.options[1] = 0x82;
557 fr_msg.options[2] = 0x53;
558 fr_msg.options[3] = 0x63;
560 uint8_t *cookie = &fr_msg.options[4];
561 uint8_t msg = DHCPV4_MSG_FORCERENEW;
563 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
564 if (a->accept_fr_nonce) {
565 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
566 auth_o = (struct dhcpv4_auth_forcerenew *)(cookie - sizeof(auth));
567 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_END, 0, NULL);
570 uint8_t secretbytes[64];
571 memset(secretbytes, 0, sizeof(secretbytes));
572 memcpy(secretbytes, a->key, sizeof(a->key));
574 for (size_t i = 0; i < sizeof(secretbytes); ++i)
575 secretbytes[i] ^= 0x36;
578 md5_hash(secretbytes, sizeof(secretbytes), &md5);
579 md5_hash(&fr_msg, sizeof(fr_msg), &md5);
580 md5_end(auth_o->key, &md5);
582 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
583 secretbytes[i] ^= 0x36;
584 secretbytes[i] ^= 0x5c;
588 md5_hash(secretbytes, sizeof(secretbytes), &md5);
589 md5_hash(auth_o->key, sizeof(auth_o->key), &md5);
590 md5_end(auth_o->key, &md5);
592 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_SERVERID, 4,
593 &a->fr_ip->addr.addr.in.s_addr);
594 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_END, 0, NULL);
597 struct sockaddr_in dest;
598 memset(&dest, 0, sizeof(dest));
599 dest.sin_family = AF_INET;
600 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
601 dest.sin_addr.s_addr = a->addr;
603 if (sendto(iface->dhcpv4_event.uloop.fd, &fr_msg, sizeof(fr_msg),
604 MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest)) < 0)
605 syslog(LOG_ERR, "Failed to send %s to %s - %s: %m", dhcpv4_msg_to_string(msg),
606 odhcpd_print_mac(a->hwaddr, sizeof(a->hwaddr)), inet_ntoa(dest.sin_addr));
608 syslog(LOG_WARNING, "Sent %s to %s - %s", dhcpv4_msg_to_string(msg),
609 odhcpd_print_mac(a->hwaddr, sizeof(a->hwaddr)), inet_ntoa(dest.sin_addr));
612 static void dhcpv4_fr_timer(struct uloop_timeout *event)
614 struct dhcpv4_assignment *a = container_of(event, struct dhcpv4_assignment, fr_timer);
616 if (a->fr_cnt > 0 && a->fr_cnt < 8) {
618 uloop_timeout_set(&a->fr_timer, 1000 << a->fr_cnt);
624 static void dhcpv4_fr_start(struct dhcpv4_assignment *a)
626 uloop_timeout_set(&a->fr_timer, 1000 << a->fr_cnt);
627 a->fr_timer.cb = dhcpv4_fr_timer;
633 static void dhcpv4_fr_delay_timer(struct uloop_timeout *event)
635 struct dhcpv4_assignment *a = container_of(event, struct dhcpv4_assignment, fr_timer);
636 struct interface *iface = a->iface;
638 (iface->dhcpv4_event.uloop.fd == -1 ? dhcpv4_fr_rand_delay(a) : dhcpv4_fr_start(a));
641 static void dhcpv4_fr_rand_delay(struct dhcpv4_assignment *a)
643 #define MIN_DELAY 500
647 odhcpd_urandom(&msecs, sizeof(msecs));
649 msecs = labs(msecs)%MAX_FUZZ + MIN_DELAY;
651 uloop_timeout_set(&a->fr_timer, msecs);
652 a->fr_timer.cb = dhcpv4_fr_delay_timer;
655 static void dhcpv4_fr_stop(struct dhcpv4_assignment *a)
657 uloop_timeout_cancel(&a->fr_timer);
658 decr_ref_cnt_ip(&a->fr_ip, a->iface);
660 a->fr_timer.cb = NULL;
663 /* Handler for DHCPv4 messages */
664 static void handle_dhcpv4(void *addr, void *data, size_t len,
665 struct interface *iface, _unused void *dest_addr)
670 struct dhcpv4_message *req = data;
671 if (len < offsetof(struct dhcpv4_message, options) + 4 ||
672 req->op != DHCPV4_BOOTREQUEST || req->hlen != 6)
676 syslog(LOG_NOTICE, "Got DHCPv4 request on %s", iface->name);
678 if (!iface->dhcpv4_start_ip.s_addr && !iface->dhcpv4_end_ip.s_addr) {
679 syslog(LOG_WARNING, "No DHCP range available on %s", iface->name);
683 int sock = iface->dhcpv4_event.uloop.fd;
685 struct dhcpv4_message reply = {
686 .op = DHCPV4_BOOTREPLY,
693 .ciaddr = {INADDR_ANY},
694 .giaddr = req->giaddr,
695 .siaddr = iface->dhcpv4_local,
697 memcpy(reply.chaddr, req->chaddr, sizeof(reply.chaddr));
699 reply.options[0] = 0x63;
700 reply.options[1] = 0x82;
701 reply.options[2] = 0x53;
702 reply.options[3] = 0x63;
704 uint8_t *cookie = &reply.options[4];
705 uint8_t reqmsg = DHCPV4_MSG_REQUEST;
706 uint8_t msg = DHCPV4_MSG_ACK;
708 uint32_t reqaddr = INADDR_ANY;
709 uint32_t leasetime = 0;
710 size_t hostname_len = 0;
712 bool accept_fr_nonce = false;
713 bool incl_fr_opt = false;
715 uint8_t *start = &req->options[4];
716 uint8_t *end = ((uint8_t*)data) + len;
717 struct dhcpv4_option *opt;
718 dhcpv4_for_each_option(start, end, opt) {
719 if (opt->type == DHCPV4_OPT_MESSAGE && opt->len == 1)
720 reqmsg = opt->data[0];
721 else if (opt->type == DHCPV4_OPT_HOSTNAME && opt->len > 0) {
722 hostname_len = opt->len;
723 memcpy(hostname, opt->data, hostname_len);
724 hostname[hostname_len] = 0;
725 } else if (opt->type == DHCPV4_OPT_IPADDRESS && opt->len == 4)
726 memcpy(&reqaddr, opt->data, 4);
727 else if (opt->type == DHCPV4_OPT_SERVERID && opt->len == 4) {
728 if (memcmp(opt->data, &iface->dhcpv4_local, 4))
730 } else if (iface->filter_class && opt->type == DHCPV4_OPT_USER_CLASS) {
731 uint8_t *c = opt->data, *cend = &opt->data[opt->len];
732 for (; c < cend && &c[*c] < cend; c = &c[1 + *c]) {
733 size_t elen = strlen(iface->filter_class);
734 if (*c == elen && !memcmp(&c[1], iface->filter_class, elen))
735 return; // Ignore from homenet
737 } else if (opt->type == DHCPV4_OPT_LEASETIME && opt->len == 4)
738 memcpy(&leasetime, opt->data, 4);
739 else if (opt->type == DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE && opt->len > 0) {
740 for (uint8_t i = 0; i < opt->len; i++) {
741 if (opt->data[i] == 1) {
742 accept_fr_nonce = true;
750 if (reqmsg != DHCPV4_MSG_DISCOVER && reqmsg != DHCPV4_MSG_REQUEST &&
751 reqmsg != DHCPV4_MSG_INFORM && reqmsg != DHCPV4_MSG_DECLINE &&
752 reqmsg != DHCPV4_MSG_RELEASE)
755 struct dhcpv4_assignment *lease = NULL;
756 uint32_t serverid = iface->dhcpv4_local.s_addr;
757 uint32_t fr_serverid = INADDR_ANY;
759 if (reqmsg != DHCPV4_MSG_INFORM)
760 lease = dhcpv4_lease(iface, reqmsg, req->chaddr, reqaddr,
761 &leasetime, hostname, hostname_len,
762 accept_fr_nonce, &incl_fr_opt, &fr_serverid);
765 if (reqmsg == DHCPV4_MSG_REQUEST)
766 msg = DHCPV4_MSG_NAK;
767 else if (reqmsg == DHCPV4_MSG_DISCOVER)
769 } else if (reqmsg == DHCPV4_MSG_DISCOVER)
770 msg = DHCPV4_MSG_OFFER;
771 else if (reqmsg == DHCPV4_MSG_REQUEST &&
772 ((reqaddr && reqaddr != lease->addr) ||
773 (req->ciaddr.s_addr && req->ciaddr.s_addr != lease->addr))) {
774 msg = DHCPV4_MSG_NAK;
776 * DHCP client requested an IP which we can't offer to him. Probably the
777 * client changed the network or the network has been changed. The reply
778 * type is set to DHCPV4_MSG_NAK, because the client should not use that IP.
780 * For modern devices we build an answer that includes a valid IP, like
781 * a DHCPV4_MSG_ACK. The client will use that IP and doesn't need to
782 * perform additional DHCP round trips.
788 * Buggy clients do serverid checking in nack messages; therefore set the
789 * serverid in nack messages triggered by a previous force renew equal to
790 * the server id in use at that time by the server
794 serverid = fr_serverid;
796 if (req->ciaddr.s_addr &&
797 ((iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr) !=
798 (req->ciaddr.s_addr & iface->dhcpv4_mask.s_addr)))
799 req->ciaddr.s_addr = INADDR_ANY;
802 syslog(LOG_WARNING, "Received %s from %s on %s", dhcpv4_msg_to_string(reqmsg),
803 odhcpd_print_mac(req->chaddr, req->hlen), iface->name);
806 if (reqmsg == DHCPV4_MSG_RELEASE)
807 ubus_bcast_dhcp_event("dhcp.release", req->chaddr, req->hlen,
808 &req->ciaddr, hostname, iface->ifname);
810 if (reqmsg == DHCPV4_MSG_DECLINE || reqmsg == DHCPV4_MSG_RELEASE)
813 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
814 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SERVERID, 4, &serverid);
819 reply.yiaddr.s_addr = lease->addr;
821 val = htonl(leasetime);
822 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_LEASETIME, 4, &val);
824 if (leasetime != UINT32_MAX) {
825 val = htonl(500 * leasetime / 1000);
826 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_RENEW, 4, &val);
828 val = htonl(875 * leasetime / 1000);
829 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_REBIND, 4, &val);
832 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_NETMASK, 4,
833 &iface->dhcpv4_mask.s_addr);
836 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_HOSTNAME,
837 strlen(lease->hostname), lease->hostname);
839 if (iface->dhcpv4_bcast.s_addr != INADDR_ANY)
840 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_BROADCAST, 4, &iface->dhcpv4_bcast);
843 if (reqmsg == DHCPV4_MSG_REQUEST) {
844 struct dhcpv4_auth_forcerenew auth = {
848 .replay = {htonl(time(NULL)), htonl(++serial)},
853 memcpy(auth.key, lease->key, sizeof(auth.key));
854 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
857 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE,
865 memset(&ifr, 0, sizeof(ifr));
866 strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name) - 1);
868 if (!ioctl(sock, SIOCGIFMTU, &ifr)) {
869 uint16_t mtu = htons(ifr.ifr_mtu);
870 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MTU, 2, &mtu);
873 if (iface->search && iface->search_len <= 255)
874 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
875 iface->search_len, iface->search);
876 else if (!res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
877 uint8_t search_buf[256];
878 int len = dn_comp(_res.dnsrch[0], search_buf,
879 sizeof(search_buf), NULL, NULL);
881 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
885 if (iface->dhcpv4_router_cnt == 0)
886 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER, 4, &iface->dhcpv4_local);
888 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER,
889 4 * iface->dhcpv4_router_cnt, iface->dhcpv4_router);
892 if (iface->dhcpv4_dns_cnt == 0)
893 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER, 4, &iface->dhcpv4_local);
895 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER,
896 4 * iface->dhcpv4_dns_cnt, iface->dhcpv4_dns);
899 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_END, 0, NULL);
901 struct sockaddr_in dest = *((struct sockaddr_in*)addr);
902 if (req->giaddr.s_addr) {
904 * relay agent is configured, send reply to the agent
906 dest.sin_addr = req->giaddr;
907 dest.sin_port = htons(DHCPV4_SERVER_PORT);
908 } else if (req->ciaddr.s_addr && req->ciaddr.s_addr != dest.sin_addr.s_addr) {
910 * client has existing configuration (ciaddr is set) AND this address is
911 * not the address it used for the dhcp message
913 dest.sin_addr = req->ciaddr;
914 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
915 } else if ((ntohs(req->flags) & DHCPV4_FLAG_BROADCAST) ||
916 req->hlen != reply.hlen || !reply.yiaddr.s_addr) {
918 * client requests a broadcast reply OR we can't offer an IP
920 dest.sin_addr.s_addr = INADDR_BROADCAST;
921 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
922 } else if (!req->ciaddr.s_addr && msg == DHCPV4_MSG_NAK) {
924 * client has no previous configuration -> no IP, so we need to reply
925 * with a broadcast packet
927 dest.sin_addr.s_addr = INADDR_BROADCAST;
928 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
930 struct arpreq arp = {.arp_flags = ATF_COM};
933 * send reply to the newly (in this proccess) allocated IP
935 dest.sin_addr = reply.yiaddr;
936 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
938 memcpy(arp.arp_ha.sa_data, req->chaddr, 6);
939 memcpy(&arp.arp_pa, &dest, sizeof(arp.arp_pa));
940 memcpy(arp.arp_dev, iface->ifname, sizeof(arp.arp_dev));
942 if (ioctl(sock, SIOCSARP, &arp) < 0)
943 syslog(LOG_ERR, "ioctl(SIOCSARP): %m");
946 if (sendto(sock, &reply, sizeof(reply), MSG_DONTWAIT,
947 (struct sockaddr*)&dest, sizeof(dest)) < 0)
948 syslog(LOG_ERR, "Failed to send %s to %s - %s: %m",
949 dhcpv4_msg_to_string(msg),
950 dest.sin_addr.s_addr == INADDR_BROADCAST ?
951 "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req->chaddr, req->hlen),
952 inet_ntoa(dest.sin_addr));
954 syslog(LOG_ERR, "Sent %s to %s - %s",
955 dhcpv4_msg_to_string(msg),
956 dest.sin_addr.s_addr == INADDR_BROADCAST ?
957 "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req->chaddr, req->hlen),
958 inet_ntoa(dest.sin_addr));
962 if (msg == DHCPV4_MSG_ACK)
963 ubus_bcast_dhcp_event("dhcp.ack", req->chaddr, req->hlen, &reply.yiaddr,
964 hostname, iface->ifname);
968 static bool dhcpv4_assign(struct interface *iface,
969 struct dhcpv4_assignment *assign, uint32_t raddr)
971 uint32_t start = ntohl(iface->dhcpv4_start_ip.s_addr);
972 uint32_t end = ntohl(iface->dhcpv4_end_ip.s_addr);
973 uint32_t count = end - start + 1;
975 /* try to assign the IP the client asked for */
976 if (start <= ntohl(raddr) && ntohl(raddr) <= end &&
977 !find_assignment_by_addr(iface, raddr)) {
978 assign->addr = raddr;
979 syslog(LOG_INFO, "Assigning the IP the client asked for: %u.%u.%u.%u",
980 ((uint8_t *)&assign->addr)[0],
981 ((uint8_t *)&assign->addr)[1],
982 ((uint8_t *)&assign->addr)[2],
983 ((uint8_t *)&assign->addr)[3]);
987 /* Seed RNG with checksum of hwaddress */
989 for (size_t i = 0; i < sizeof(assign->hwaddr); ++i) {
990 /* Knuth's multiplicative method */
991 uint8_t o = assign->hwaddr[i];
992 seed += (o*2654435761) % UINT32_MAX;
997 uint32_t try = (((uint32_t)rand()) % count) + start;
999 if (list_empty(&iface->dhcpv4_assignments)) {
1000 assign->addr = htonl(try);
1001 syslog(LOG_INFO, "Assigning mapped IP (empty list): %u.%u.%u.%u",
1002 ((uint8_t *)&assign->addr)[0],
1003 ((uint8_t *)&assign->addr)[1],
1004 ((uint8_t *)&assign->addr)[2],
1005 ((uint8_t *)&assign->addr)[3]);
1009 for (uint32_t i = 0; i < count; ++i) {
1010 if (!find_assignment_by_addr(iface, htonl(try))) {
1011 /* test was successful: IP address is not assigned, assign it */
1012 assign->addr = htonl(try);
1013 syslog(LOG_DEBUG, "Assigning mapped IP: %u.%u.%u.%u (try %u of %u)",
1014 ((uint8_t *)&assign->addr)[0],
1015 ((uint8_t *)&assign->addr)[1],
1016 ((uint8_t *)&assign->addr)[2],
1017 ((uint8_t *)&assign->addr)[3],
1021 try = (((try - start) + 1) % count) + start;
1024 syslog(LOG_WARNING, "Can't assign any IP address -> address space is full");
1029 static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
1030 enum dhcpv4_msg msg, const uint8_t *mac, const uint32_t reqaddr,
1031 uint32_t *leasetime, const char *hostname, const size_t hostname_len,
1032 const bool accept_fr_nonce, bool *incl_fr_opt, uint32_t *fr_serverid)
1034 struct dhcpv4_assignment *a = find_assignment_by_hwaddr(iface, mac);
1035 struct dhcpv4_assignment *lease = NULL;
1036 time_t now = odhcpd_time();
1038 if (a && (a->flags & OAF_BOUND) && a->fr_ip) {
1039 *fr_serverid = a->fr_ip->addr.addr.in.s_addr;
1043 if (msg == DHCPV4_MSG_DISCOVER || msg == DHCPV4_MSG_REQUEST) {
1044 bool assigned = !!a;
1047 if (!iface->no_dynamic_dhcp) {
1048 /* Create new binding */
1049 a = calloc(1, sizeof(*a));
1051 syslog(LOG_ERR, "Failed to calloc binding on interface %s",
1055 memcpy(a->hwaddr, mac, sizeof(a->hwaddr));
1056 /* Don't consider new assignment as infinite */
1057 a->valid_until = now;
1059 assigned = dhcpv4_assign(iface, a, reqaddr);
1062 list_add(&a->head, &iface->dhcpv4_assignments);
1065 } else if ((a->addr & iface->dhcpv4_mask.s_addr) !=
1066 (iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr)) {
1069 assigned = dhcpv4_assign(iface, a, reqaddr);
1071 list_add(&a->head, &iface->dhcpv4_assignments);
1075 uint32_t my_leasetime;
1078 my_leasetime = a->leasetime;
1080 my_leasetime = iface->dhcpv4_leasetime;
1082 if ((*leasetime == 0) || (my_leasetime < *leasetime))
1083 *leasetime = my_leasetime;
1085 if (msg == DHCPV4_MSG_DISCOVER) {
1086 a->flags &= ~OAF_BOUND;
1088 *incl_fr_opt = accept_fr_nonce;
1089 if (!(a->flags & OAF_STATIC))
1090 a->valid_until = now;
1092 if (hostname_len > 0) {
1093 a->hostname = realloc(a->hostname, hostname_len + 1);
1095 memcpy(a->hostname, hostname, hostname_len);
1096 a->hostname[hostname_len] = 0;
1098 if (odhcpd_valid_hostname(a->hostname))
1099 a->flags &= ~OAF_BROKEN_HOSTNAME;
1101 a->flags |= OAF_BROKEN_HOSTNAME;
1105 if (!(a->flags & OAF_BOUND)) {
1106 a->accept_fr_nonce = accept_fr_nonce;
1107 *incl_fr_opt = accept_fr_nonce;
1108 odhcpd_urandom(a->key, sizeof(a->key));
1109 a->flags |= OAF_BOUND;
1111 *incl_fr_opt = false;
1113 if (!(a->flags & OAF_STATIC))
1114 a->valid_until = ((*leasetime == UINT32_MAX) ? 0 : (time_t)(now + *leasetime));
1116 } else if (!assigned && a) {
1117 /* Cleanup failed assignment */
1118 free_dhcpv4_assignment(a);
1124 } else if (msg == DHCPV4_MSG_RELEASE && a) {
1125 a->flags &= ~OAF_BOUND;
1127 if (!(a->flags & OAF_STATIC))
1128 a->valid_until = now - 1;
1130 } else if (msg == DHCPV4_MSG_DECLINE && a) {
1131 a->flags &= ~OAF_BOUND;
1133 if (!(a->flags & OAF_STATIC)) {
1134 memset(a->hwaddr, 0, sizeof(a->hwaddr));
1135 a->valid_until = now + 3600; /* Block address for 1h */
1139 dhcpv6_write_statefile();