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 #define PACKET_SIZE(start, end) (((uint8_t *)end - (uint8_t *)start) < DHCPV4_MIN_PACKET_SIZE ? \
39 DHCPV4_MIN_PACKET_SIZE : (uint8_t *)end - (uint8_t *)start)
41 static void dhcpv4_netevent_cb(unsigned long event, struct netevent_handler_info *info);
42 static int setup_dhcpv4_addresses(struct interface *iface);
43 static bool addr_is_fr_ip(struct interface *iface, struct in_addr *addr);
44 static void valid_until_cb(struct uloop_timeout *event);
45 static void handle_addrlist_change(struct interface *iface);
46 static void dhcpv4_fr_start(struct dhcp_assignment *a);
47 static void dhcpv4_fr_rand_delay(struct dhcp_assignment *a);
48 static void dhcpv4_fr_stop(struct dhcp_assignment *a);
49 static void handle_dhcpv4(void *addr, void *data, size_t len,
50 struct interface *iface, void *dest_addr);
51 static struct dhcp_assignment* dhcpv4_lease(struct interface *iface,
52 enum dhcpv4_msg msg, const uint8_t *mac, const uint32_t reqaddr,
53 uint32_t *leasetime, const char *hostname, const size_t hostname_len,
54 const bool accept_fr_nonce, bool *incl_fr_opt, uint32_t *fr_serverid,
55 const char *reqopts, const size_t reqopts_len);
57 static struct netevent_handler dhcpv4_netevent_handler = { .cb = dhcpv4_netevent_cb, };
58 static struct uloop_timeout valid_until_timeout = {.cb = valid_until_cb};
59 static uint32_t serial = 0;
61 struct odhcpd_ref_ip {
62 struct list_head head;
64 struct odhcpd_ipaddr addr;
67 /* Create socket and register events */
70 uloop_timeout_set(&valid_until_timeout, 1000);
71 netlink_add_netevent_handler(&dhcpv4_netevent_handler);
76 int dhcpv4_setup_interface(struct interface *iface, bool enable)
80 enable = enable && (iface->dhcpv4 != MODE_DISABLED);
82 if (iface->dhcpv4_event.uloop.fd >= 0) {
83 uloop_fd_delete(&iface->dhcpv4_event.uloop);
84 close(iface->dhcpv4_event.uloop.fd);
85 iface->dhcpv4_event.uloop.fd = -1;
89 struct sockaddr_in bind_addr = {AF_INET, htons(DHCPV4_SERVER_PORT),
93 iface->dhcpv4_event.uloop.fd = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
94 if (iface->dhcpv4_event.uloop.fd < 0) {
95 syslog(LOG_ERR, "socket(AF_INET): %m");
100 /* Basic IPv4 configuration */
101 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_REUSEADDR,
102 &val, sizeof(val)) < 0) {
103 syslog(LOG_ERR, "setsockopt(SO_REUSEADDR): %m");
108 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_BROADCAST,
109 &val, sizeof(val)) < 0) {
110 syslog(LOG_ERR, "setsockopt(SO_BROADCAST): %m");
115 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_PKTINFO,
116 &val, sizeof(val)) < 0) {
117 syslog(LOG_ERR, "setsockopt(IP_PKTINFO): %m");
122 val = IPTOS_PREC_INTERNETCONTROL;
123 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_TOS,
124 &val, sizeof(val)) < 0) {
125 syslog(LOG_ERR, "setsockopt(IP_TOS): %m");
130 val = IP_PMTUDISC_DONT;
131 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_MTU_DISCOVER,
132 &val, sizeof(val)) < 0) {
133 syslog(LOG_ERR, "setsockopt(IP_MTU_DISCOVER): %m");
138 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_BINDTODEVICE,
139 iface->ifname, strlen(iface->ifname)) < 0) {
140 syslog(LOG_ERR, "setsockopt(SO_BINDTODEVICE): %m");
145 if (bind(iface->dhcpv4_event.uloop.fd, (struct sockaddr*)&bind_addr,
146 sizeof(bind_addr)) < 0) {
147 syslog(LOG_ERR, "bind(): %m");
152 if (setup_dhcpv4_addresses(iface) < 0) {
157 iface->dhcpv4_event.handle_dgram = handle_dhcpv4;
158 odhcpd_register(&iface->dhcpv4_event);
160 while (!list_empty(&iface->dhcpv4_assignments))
161 free_assignment(list_first_entry(&iface->dhcpv4_assignments,
162 struct dhcp_assignment, head));
166 if (ret < 0 && iface->dhcpv4_event.uloop.fd >= 0) {
167 close(iface->dhcpv4_event.uloop.fd);
168 iface->dhcpv4_event.uloop.fd = -1;
175 static void dhcpv4_netevent_cb(unsigned long event, struct netevent_handler_info *info)
177 struct interface *iface = info->iface;
179 if (!iface || iface->dhcpv4 == MODE_DISABLED)
183 case NETEV_IFINDEX_CHANGE:
184 dhcpv4_setup_interface(iface, true);
186 case NETEV_ADDRLIST_CHANGE:
187 handle_addrlist_change(iface);
194 static struct dhcp_assignment *find_assignment_by_hwaddr(struct interface *iface, const uint8_t *hwaddr)
196 struct dhcp_assignment *a;
198 list_for_each_entry(a, &iface->dhcpv4_assignments, head)
199 if (!memcmp(a->hwaddr, hwaddr, 6))
205 static int setup_dhcpv4_addresses(struct interface *iface)
207 iface->dhcpv4_start_ip.s_addr = INADDR_ANY;
208 iface->dhcpv4_end_ip.s_addr = INADDR_ANY;
209 iface->dhcpv4_local.s_addr = INADDR_ANY;
210 iface->dhcpv4_bcast.s_addr = INADDR_ANY;
211 iface->dhcpv4_mask.s_addr = INADDR_ANY;
214 if (iface->dhcpv4_start.s_addr & htonl(0xffff0000) ||
215 iface->dhcpv4_end.s_addr & htonl(0xffff0000) ||
216 ntohl(iface->dhcpv4_start.s_addr) > ntohl(iface->dhcpv4_end.s_addr)) {
217 syslog(LOG_ERR, "Invalid DHCP range for %s", iface->name);
221 if (!iface->addr4_len) {
222 syslog(LOG_ERR, "No network(s) available on %s", iface->name);
226 uint32_t start = ntohl(iface->dhcpv4_start.s_addr);
227 uint32_t end = ntohl(iface->dhcpv4_end.s_addr);
229 for (size_t i = 0; i < iface->addr4_len && start && end; i++) {
230 struct in_addr *addr = &iface->addr4[i].addr.in;
233 if (addr_is_fr_ip(iface, addr))
236 odhcpd_bitlen2netmask(false, iface->addr4[i].prefix, &mask);
237 if ((start & ntohl(~mask.s_addr)) == start &&
238 (end & ntohl(~mask.s_addr)) == end &&
239 end < ntohl(~mask.s_addr)) { /* Exclude broadcast address */
240 iface->dhcpv4_start_ip.s_addr = htonl(start) |
241 (addr->s_addr & mask.s_addr);
242 iface->dhcpv4_end_ip.s_addr = htonl(end) |
243 (addr->s_addr & mask.s_addr);
244 iface->dhcpv4_local = *addr;
245 iface->dhcpv4_bcast = iface->addr4[i].broadcast;
246 iface->dhcpv4_mask = mask;
251 /* Don't allocate IP range for subnets bigger than 28 */
252 if (iface->addr4[0].prefix > 28) {
253 syslog(LOG_ERR, "Auto allocation of DHCP range fails on %s", iface->name);
257 iface->dhcpv4_local = iface->addr4[0].addr.in;
258 iface->dhcpv4_bcast = iface->addr4[0].broadcast;
259 odhcpd_bitlen2netmask(false, iface->addr4[0].prefix, &iface->dhcpv4_mask);
260 end = start = iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr;
262 /* Auto allocate ranges */
263 if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffff00) { /* /24, 150 of 256, [100..249] */
264 iface->dhcpv4_start_ip.s_addr = start | htonl(100);
265 iface->dhcpv4_end_ip.s_addr = end | htonl(100 + 150 - 1);
266 } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffff80) { /* /25, 100 of 128, [20..119] */
267 iface->dhcpv4_start_ip.s_addr = start | htonl(20);
268 iface->dhcpv4_end_ip.s_addr = end | htonl(20 + 100 - 1);
269 } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffc0) { /* /26, 50 of 64, [10..59] */
270 iface->dhcpv4_start_ip.s_addr = start | htonl(10);
271 iface->dhcpv4_end_ip.s_addr = end | htonl(10 + 50 - 1);
272 } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffe0) { /* /27, 20 of 32, [10..29] */
273 iface->dhcpv4_start_ip.s_addr = start | htonl(10);
274 iface->dhcpv4_end_ip.s_addr = end | htonl(10 + 20 - 1);
275 } else { /* /28, 10 of 16, [3..12] */
276 iface->dhcpv4_start_ip.s_addr = start | htonl(3);
277 iface->dhcpv4_end_ip.s_addr = end | htonl(3 + 10 - 1);
283 static void inc_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct odhcpd_ref_ip *ip)
289 static void decr_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct interface *iface)
291 struct odhcpd_ref_ip *ip = *ptr;
293 if (--ip->ref_cnt == 0) {
294 netlink_setup_addr(&ip->addr, iface->ifindex, false, false);
303 static bool addr_is_fr_ip(struct interface *iface, struct in_addr *addr)
305 struct odhcpd_ref_ip *p;
307 list_for_each_entry(p, &iface->dhcpv4_fr_ips, head) {
308 if (addr->s_addr == p->addr.addr.in.s_addr)
315 static bool leases_require_fr(struct interface *iface, struct odhcpd_ipaddr *addr,
318 struct dhcp_assignment *a = NULL;
319 struct odhcpd_ref_ip *fr_ip = NULL;
321 list_for_each_entry(a, &iface->dhcpv4_assignments, head) {
322 if ((a->accept_fr_nonce || iface->dhcpv4_forcereconf) &&
324 ((a->addr & mask) == (addr->addr.in.s_addr & mask))) {
326 fr_ip = calloc(1, sizeof(*fr_ip));
330 list_add(&fr_ip->head, &iface->dhcpv4_fr_ips);
333 inc_ref_cnt_ip(&a->fr_ip, fr_ip);
337 return fr_ip ? true : false;
340 static void valid_until_cb(struct uloop_timeout *event)
342 struct interface *iface;
343 time_t now = odhcpd_time();
345 avl_for_each_element(&interfaces, iface, avl) {
346 struct dhcp_assignment *a, *n;
348 if (iface->dhcpv4 != MODE_SERVER)
351 list_for_each_entry_safe(a, n, &iface->dhcpv4_assignments, head) {
352 if (!INFINITE_VALID(a->valid_until) && a->valid_until < now)
356 uloop_timeout_set(event, 1000);
359 static void handle_addrlist_change(struct interface *iface)
361 struct odhcpd_ipaddr ip;
362 struct odhcpd_ref_ip *a;
363 struct dhcp_assignment *c;
364 uint32_t mask = iface->dhcpv4_mask.s_addr;
366 memset(&ip, 0, sizeof(ip));
367 ip.addr.in = iface->dhcpv4_local;
368 ip.prefix = odhcpd_netmask2bitlen(false, &iface->dhcpv4_mask);
369 ip.broadcast = iface->dhcpv4_bcast;
371 setup_dhcpv4_addresses(iface);
373 if ((ip.addr.in.s_addr & mask) ==
374 (iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr))
377 if (ip.addr.in.s_addr && !leases_require_fr(iface, &ip, mask))
380 if (iface->dhcpv4_local.s_addr == INADDR_ANY || list_empty(&iface->dhcpv4_fr_ips))
383 a = list_first_entry(&iface->dhcpv4_fr_ips, struct odhcpd_ref_ip, head);
385 if (netlink_setup_addr(&a->addr, iface->ifindex, false, true)) {
386 syslog(LOG_ERR, "Failed to add ip address on %s", iface->name);
390 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
391 if ((c->flags & OAF_BOUND) && c->fr_ip && !c->fr_cnt) {
392 if (c->accept_fr_nonce || iface->dhcpv4_forcereconf)
393 dhcpv4_fr_rand_delay(c);
400 static char *dhcpv4_msg_to_string(uint8_t reqmsg)
403 case (DHCPV4_MSG_DISCOVER):
404 return "DHCPV4_MSG_DISCOVER";
405 case (DHCPV4_MSG_OFFER):
406 return "DHCPV4_MSG_OFFER";
407 case (DHCPV4_MSG_REQUEST):
408 return "DHCPV4_MSG_REQUEST";
409 case (DHCPV4_MSG_DECLINE):
410 return "DHCPV4_MSG_DECLINE";
411 case (DHCPV4_MSG_ACK):
412 return "DHCPV4_MSG_ACK";
413 case (DHCPV4_MSG_NAK):
414 return "DHCPV4_MSG_NAK";
415 case (DHCPV4_MSG_RELEASE):
416 return "DHCPV4_MSG_RELEASE";
417 case (DHCPV4_MSG_INFORM):
418 return "DHCPV4_MSG_INFORM";
419 case (DHCPV4_MSG_FORCERENEW):
420 return "DHCPV4_MSG_FORCERENEW";
426 static void dhcpv4_free_assignment(struct dhcp_assignment *a)
432 static void dhcpv4_put(struct dhcpv4_message *msg, uint8_t **cookie,
433 uint8_t type, uint8_t len, const void *data)
435 uint8_t *c = *cookie;
436 uint8_t *end = (uint8_t *)msg + sizeof(*msg);
437 bool tag_only = type == DHCPV4_OPT_PAD || type == DHCPV4_OPT_END;
438 int total_len = tag_only ? 1 : 2 + len;
440 if (*cookie + total_len > end)
443 *cookie += total_len;
450 memcpy(c, data, len);
453 static void dhcpv4_fr_send(struct dhcp_assignment *a)
455 struct dhcpv4_message fr_msg = {
456 .op = DHCPV4_BOOTREPLY,
462 .ciaddr = {INADDR_ANY},
463 .yiaddr = {INADDR_ANY},
464 .siaddr = {INADDR_ANY},
465 .giaddr = {INADDR_ANY},
470 struct dhcpv4_auth_forcerenew *auth_o, auth = {
474 .replay = {htonl(time(NULL)), htonl(++serial)},
478 struct interface *iface = a->iface;
480 odhcpd_urandom(&fr_msg.xid, sizeof(fr_msg.xid));
481 memcpy(fr_msg.chaddr, a->hwaddr, fr_msg.hlen);
483 fr_msg.options[0] = 0x63;
484 fr_msg.options[1] = 0x82;
485 fr_msg.options[2] = 0x53;
486 fr_msg.options[3] = 0x63;
488 uint8_t *cookie = &fr_msg.options[4];
489 uint8_t msg = DHCPV4_MSG_FORCERENEW;
491 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
492 if (a->accept_fr_nonce) {
493 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
494 auth_o = (struct dhcpv4_auth_forcerenew *)(cookie - sizeof(auth));
495 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_END, 0, NULL);
498 uint8_t secretbytes[64];
499 memset(secretbytes, 0, sizeof(secretbytes));
500 memcpy(secretbytes, a->key, sizeof(a->key));
502 for (size_t i = 0; i < sizeof(secretbytes); ++i)
503 secretbytes[i] ^= 0x36;
506 md5_hash(secretbytes, sizeof(secretbytes), &md5);
507 md5_hash(&fr_msg, sizeof(fr_msg), &md5);
508 md5_end(auth_o->key, &md5);
510 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
511 secretbytes[i] ^= 0x36;
512 secretbytes[i] ^= 0x5c;
516 md5_hash(secretbytes, sizeof(secretbytes), &md5);
517 md5_hash(auth_o->key, sizeof(auth_o->key), &md5);
518 md5_end(auth_o->key, &md5);
520 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_SERVERID, 4,
521 &a->fr_ip->addr.addr.in.s_addr);
522 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_END, 0, NULL);
525 struct sockaddr_in dest;
526 memset(&dest, 0, sizeof(dest));
527 dest.sin_family = AF_INET;
528 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
529 dest.sin_addr.s_addr = a->addr;
531 if (sendto(iface->dhcpv4_event.uloop.fd, &fr_msg, PACKET_SIZE(&fr_msg, cookie),
532 MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest)) < 0)
533 syslog(LOG_ERR, "Failed to send %s to %s - %s: %m", dhcpv4_msg_to_string(msg),
534 odhcpd_print_mac(a->hwaddr, sizeof(a->hwaddr)), inet_ntoa(dest.sin_addr));
536 syslog(LOG_NOTICE, "Sent %s to %s - %s", dhcpv4_msg_to_string(msg),
537 odhcpd_print_mac(a->hwaddr, sizeof(a->hwaddr)), inet_ntoa(dest.sin_addr));
540 static void dhcpv4_fr_timer(struct uloop_timeout *event)
542 struct dhcp_assignment *a = container_of(event, struct dhcp_assignment, fr_timer);
544 if (a->fr_cnt > 0 && a->fr_cnt < 8) {
546 uloop_timeout_set(&a->fr_timer, 1000 << a->fr_cnt);
552 static void dhcpv4_fr_start(struct dhcp_assignment *a)
554 uloop_timeout_set(&a->fr_timer, 1000 << a->fr_cnt);
555 a->fr_timer.cb = dhcpv4_fr_timer;
561 static void dhcpv4_fr_delay_timer(struct uloop_timeout *event)
563 struct dhcp_assignment *a = container_of(event, struct dhcp_assignment, fr_timer);
564 struct interface *iface = a->iface;
566 (iface->dhcpv4_event.uloop.fd == -1 ? dhcpv4_fr_rand_delay(a) : dhcpv4_fr_start(a));
569 static void dhcpv4_fr_rand_delay(struct dhcp_assignment *a)
571 #define MIN_DELAY 500
575 odhcpd_urandom(&msecs, sizeof(msecs));
577 msecs = labs(msecs)%MAX_FUZZ + MIN_DELAY;
579 uloop_timeout_set(&a->fr_timer, msecs);
580 a->fr_timer.cb = dhcpv4_fr_delay_timer;
583 static void dhcpv4_fr_stop(struct dhcp_assignment *a)
585 uloop_timeout_cancel(&a->fr_timer);
586 decr_ref_cnt_ip(&a->fr_ip, a->iface);
588 a->fr_timer.cb = NULL;
591 /* Handler for DHCPv4 messages */
592 static void handle_dhcpv4(void *addr, void *data, size_t len,
593 struct interface *iface, _unused void *dest_addr)
595 struct dhcpv4_message *req = data;
597 if (iface->dhcpv4 == MODE_DISABLED)
600 if (len < offsetof(struct dhcpv4_message, options) + 4 ||
601 req->op != DHCPV4_BOOTREQUEST || req->hlen != 6)
604 syslog(LOG_NOTICE, "Got DHCPv4 request on %s", iface->name);
606 if (!iface->dhcpv4_start_ip.s_addr && !iface->dhcpv4_end_ip.s_addr) {
607 syslog(LOG_ERR, "No DHCP range available on %s", iface->name);
611 int sock = iface->dhcpv4_event.uloop.fd;
613 struct dhcpv4_message reply = {
614 .op = DHCPV4_BOOTREPLY,
621 .ciaddr = {INADDR_ANY},
622 .giaddr = req->giaddr,
623 .siaddr = iface->dhcpv4_local,
625 memcpy(reply.chaddr, req->chaddr, sizeof(reply.chaddr));
627 reply.options[0] = 0x63;
628 reply.options[1] = 0x82;
629 reply.options[2] = 0x53;
630 reply.options[3] = 0x63;
632 uint8_t *cookie = &reply.options[4];
633 uint8_t reqmsg = DHCPV4_MSG_REQUEST;
634 uint8_t msg = DHCPV4_MSG_ACK;
636 uint32_t reqaddr = INADDR_ANY;
637 uint32_t leasetime = 0;
638 size_t hostname_len = 0;
639 size_t reqopts_len = 0;
642 bool accept_fr_nonce = false;
643 bool incl_fr_opt = false;
645 uint8_t *start = &req->options[4];
646 uint8_t *end = ((uint8_t*)data) + len;
647 struct dhcpv4_option *opt;
648 dhcpv4_for_each_option(start, end, opt) {
649 if (opt->type == DHCPV4_OPT_MESSAGE && opt->len == 1)
650 reqmsg = opt->data[0];
651 else if (opt->type == DHCPV4_OPT_REQOPTS && opt->len > 0) {
652 reqopts_len = opt->len;
653 memcpy(reqopts, opt->data, reqopts_len);
654 reqopts[reqopts_len] = 0;
655 } else if (opt->type == DHCPV4_OPT_HOSTNAME && opt->len > 0) {
656 hostname_len = opt->len;
657 memcpy(hostname, opt->data, hostname_len);
658 hostname[hostname_len] = 0;
659 } else if (opt->type == DHCPV4_OPT_IPADDRESS && opt->len == 4)
660 memcpy(&reqaddr, opt->data, 4);
661 else if (opt->type == DHCPV4_OPT_SERVERID && opt->len == 4) {
662 if (memcmp(opt->data, &iface->dhcpv4_local, 4))
664 } else if (iface->filter_class && opt->type == DHCPV4_OPT_USER_CLASS) {
665 uint8_t *c = opt->data, *cend = &opt->data[opt->len];
666 for (; c < cend && &c[*c] < cend; c = &c[1 + *c]) {
667 size_t elen = strlen(iface->filter_class);
668 if (*c == elen && !memcmp(&c[1], iface->filter_class, elen))
669 return; // Ignore from homenet
671 } else if (opt->type == DHCPV4_OPT_LEASETIME && opt->len == 4)
672 memcpy(&leasetime, opt->data, 4);
673 else if (opt->type == DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE && opt->len > 0) {
674 for (uint8_t i = 0; i < opt->len; i++) {
675 if (opt->data[i] == 1) {
676 accept_fr_nonce = true;
684 if (reqmsg != DHCPV4_MSG_DISCOVER && reqmsg != DHCPV4_MSG_REQUEST &&
685 reqmsg != DHCPV4_MSG_INFORM && reqmsg != DHCPV4_MSG_DECLINE &&
686 reqmsg != DHCPV4_MSG_RELEASE)
689 struct dhcp_assignment *a = NULL;
690 uint32_t serverid = iface->dhcpv4_local.s_addr;
691 uint32_t fr_serverid = INADDR_ANY;
693 if (reqmsg != DHCPV4_MSG_INFORM)
694 a = dhcpv4_lease(iface, reqmsg, req->chaddr, reqaddr,
695 &leasetime, hostname, hostname_len,
696 accept_fr_nonce, &incl_fr_opt, &fr_serverid,
697 reqopts, reqopts_len);
700 if (reqmsg == DHCPV4_MSG_REQUEST)
701 msg = DHCPV4_MSG_NAK;
702 else if (reqmsg == DHCPV4_MSG_DISCOVER)
704 } else if (reqmsg == DHCPV4_MSG_DISCOVER)
705 msg = DHCPV4_MSG_OFFER;
706 else if (reqmsg == DHCPV4_MSG_REQUEST &&
707 ((reqaddr && reqaddr != a->addr) ||
708 (req->ciaddr.s_addr && req->ciaddr.s_addr != a->addr))) {
709 msg = DHCPV4_MSG_NAK;
711 * DHCP client requested an IP which we can't offer to him. Probably the
712 * client changed the network or the network has been changed. The reply
713 * type is set to DHCPV4_MSG_NAK, because the client should not use that IP.
715 * For modern devices we build an answer that includes a valid IP, like
716 * a DHCPV4_MSG_ACK. The client will use that IP and doesn't need to
717 * perform additional DHCP round trips.
723 * Buggy clients do serverid checking in nack messages; therefore set the
724 * serverid in nack messages triggered by a previous force renew equal to
725 * the server id in use at that time by the server
729 serverid = fr_serverid;
731 if (req->ciaddr.s_addr &&
732 ((iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr) !=
733 (req->ciaddr.s_addr & iface->dhcpv4_mask.s_addr)))
734 req->ciaddr.s_addr = INADDR_ANY;
737 syslog(LOG_NOTICE, "Received %s from %s on %s", dhcpv4_msg_to_string(reqmsg),
738 odhcpd_print_mac(req->chaddr, req->hlen), iface->name);
741 if (reqmsg == DHCPV4_MSG_RELEASE)
742 ubus_bcast_dhcp_event("dhcp.release", req->chaddr, req->hlen,
743 &req->ciaddr, hostname, iface->ifname);
745 if (reqmsg == DHCPV4_MSG_DECLINE || reqmsg == DHCPV4_MSG_RELEASE)
748 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
749 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SERVERID, 4, &serverid);
754 reply.yiaddr.s_addr = a->addr;
756 val = htonl(leasetime);
757 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_LEASETIME, 4, &val);
759 if (leasetime != UINT32_MAX) {
760 val = htonl(500 * leasetime / 1000);
761 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_RENEW, 4, &val);
763 val = htonl(875 * leasetime / 1000);
764 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_REBIND, 4, &val);
767 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_NETMASK, 4,
768 &iface->dhcpv4_mask.s_addr);
771 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_HOSTNAME,
772 strlen(a->hostname), a->hostname);
774 if (iface->dhcpv4_bcast.s_addr != INADDR_ANY)
775 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_BROADCAST, 4, &iface->dhcpv4_bcast);
778 if (reqmsg == DHCPV4_MSG_REQUEST) {
779 struct dhcpv4_auth_forcerenew auth = {
783 .replay = {htonl(time(NULL)), htonl(++serial)},
788 memcpy(auth.key, a->key, sizeof(auth.key));
789 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
792 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE,
800 memset(&ifr, 0, sizeof(ifr));
801 strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name) - 1);
803 if (!ioctl(sock, SIOCGIFMTU, &ifr)) {
804 uint16_t mtu = htons(ifr.ifr_mtu);
805 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MTU, 2, &mtu);
808 if (iface->search && iface->search_len <= 255)
809 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
810 iface->search_len, iface->search);
811 else if (!res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
812 uint8_t search_buf[256];
813 int len = dn_comp(_res.dnsrch[0], search_buf,
814 sizeof(search_buf), NULL, NULL);
816 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
820 if (iface->dhcpv4_router_cnt == 0)
821 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER, 4, &iface->dhcpv4_local);
823 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER,
824 4 * iface->dhcpv4_router_cnt, iface->dhcpv4_router);
827 if (iface->dhcpv4_dns_cnt == 0)
828 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER, 4, &iface->dhcpv4_local);
830 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER,
831 4 * iface->dhcpv4_dns_cnt, iface->dhcpv4_dns);
834 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_END, 0, NULL);
836 struct sockaddr_in dest = *((struct sockaddr_in*)addr);
837 if (req->giaddr.s_addr) {
839 * relay agent is configured, send reply to the agent
841 dest.sin_addr = req->giaddr;
842 dest.sin_port = htons(DHCPV4_SERVER_PORT);
843 } else if (req->ciaddr.s_addr && req->ciaddr.s_addr != dest.sin_addr.s_addr) {
845 * client has existing configuration (ciaddr is set) AND this address is
846 * not the address it used for the dhcp message
848 dest.sin_addr = req->ciaddr;
849 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
850 } else if ((ntohs(req->flags) & DHCPV4_FLAG_BROADCAST) ||
851 req->hlen != reply.hlen || !reply.yiaddr.s_addr) {
853 * client requests a broadcast reply OR we can't offer an IP
855 dest.sin_addr.s_addr = INADDR_BROADCAST;
856 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
857 } else if (!req->ciaddr.s_addr && msg == DHCPV4_MSG_NAK) {
859 * client has no previous configuration -> no IP, so we need to reply
860 * with a broadcast packet
862 dest.sin_addr.s_addr = INADDR_BROADCAST;
863 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
865 struct arpreq arp = {.arp_flags = ATF_COM};
868 * send reply to the newly (in this proccess) allocated IP
870 dest.sin_addr = reply.yiaddr;
871 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
873 memcpy(arp.arp_ha.sa_data, req->chaddr, 6);
874 memcpy(&arp.arp_pa, &dest, sizeof(arp.arp_pa));
875 memcpy(arp.arp_dev, iface->ifname, sizeof(arp.arp_dev));
877 if (ioctl(sock, SIOCSARP, &arp) < 0)
878 syslog(LOG_ERR, "ioctl(SIOCSARP): %m");
881 if (sendto(sock, &reply, PACKET_SIZE(&reply, cookie), MSG_DONTWAIT,
882 (struct sockaddr*)&dest, sizeof(dest)) < 0)
883 syslog(LOG_ERR, "Failed to send %s to %s - %s: %m",
884 dhcpv4_msg_to_string(msg),
885 dest.sin_addr.s_addr == INADDR_BROADCAST ?
886 "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req->chaddr, req->hlen),
887 inet_ntoa(dest.sin_addr));
889 syslog(LOG_NOTICE, "Sent %s to %s - %s",
890 dhcpv4_msg_to_string(msg),
891 dest.sin_addr.s_addr == INADDR_BROADCAST ?
892 "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req->chaddr, req->hlen),
893 inet_ntoa(dest.sin_addr));
897 if (msg == DHCPV4_MSG_ACK)
898 ubus_bcast_dhcp_event("dhcp.ack", req->chaddr, req->hlen, &reply.yiaddr,
899 hostname, iface->ifname);
903 static bool dhcpv4_insert_assignment(struct list_head *list, struct dhcp_assignment *a,
906 uint32_t h_addr = ntohl(addr);
907 struct dhcp_assignment *c;
909 list_for_each_entry(c, list, head) {
910 uint32_t c_addr = ntohl(c->addr);
912 if (c_addr == h_addr)
919 /* Insert new node before c (might match list head) */
921 list_add_tail(&a->head, &c->head);
926 static char* ip4toa(uint32_t addr)
930 snprintf(buf, sizeof(buf), "%u.%u.%u.%u",
931 ((uint8_t *)&addr)[0], ((uint8_t *)&addr)[1],
932 ((uint8_t *)&addr)[2], ((uint8_t *)&addr)[3]);
937 static bool dhcpv4_assign(struct interface *iface, struct dhcp_assignment *a,
940 uint32_t start = ntohl(iface->dhcpv4_start_ip.s_addr);
941 uint32_t end = ntohl(iface->dhcpv4_end_ip.s_addr);
942 uint32_t count = end - start + 1;
946 /* Preconfigured IP address by static lease */
948 assigned = dhcpv4_insert_assignment(&iface->dhcpv4_assignments,
952 syslog(LOG_INFO, "Assigning static IP: %s", ip4toa(a->addr));
957 /* try to assign the IP the client asked for */
958 if (start <= ntohl(raddr) && ntohl(raddr) <= end &&
959 !config_find_lease_by_ipaddr(raddr)) {
960 assigned = dhcpv4_insert_assignment(&iface->dhcpv4_assignments,
964 syslog(LOG_INFO, "Assigning the IP the client asked for: %s",
971 /* Seed RNG with checksum of hwaddress */
972 for (size_t i = 0; i < sizeof(a->hwaddr); ++i) {
973 /* Knuth's multiplicative method */
974 uint8_t o = a->hwaddr[i];
975 seed += (o*2654435761) % UINT32_MAX;
980 for (uint32_t i = 0, try = (((uint32_t)rand()) % count) + start; i < count;
981 ++i, try = (((try - start) + 1) % count) + start) {
982 uint32_t n_try = htonl(try);
984 if (config_find_lease_by_ipaddr(n_try))
987 assigned = dhcpv4_insert_assignment(&iface->dhcpv4_assignments,
991 syslog(LOG_INFO, "Assigning mapped IP: %s (try %u of %u)",
992 ip4toa(a->addr), i + 1, count);
998 syslog(LOG_WARNING, "Can't assign any IP address -> address space is full");
1003 static struct dhcp_assignment*
1004 dhcpv4_lease(struct interface *iface, enum dhcpv4_msg msg, const uint8_t *mac,
1005 const uint32_t reqaddr, uint32_t *leasetime, const char *hostname,
1006 const size_t hostname_len, const bool accept_fr_nonce, bool *incl_fr_opt,
1007 uint32_t *fr_serverid, const char* reqopts, const size_t reqopts_len)
1009 struct dhcp_assignment *a = find_assignment_by_hwaddr(iface, mac);
1010 struct lease *l = config_find_lease_by_mac(mac);
1011 time_t now = odhcpd_time();
1013 if (l && a && a->lease != l) {
1018 if (a && (a->flags & OAF_BOUND) && a->fr_ip) {
1019 *fr_serverid = a->fr_ip->addr.addr.in.s_addr;
1023 if (msg == DHCPV4_MSG_DISCOVER || msg == DHCPV4_MSG_REQUEST) {
1024 bool assigned = !!a;
1027 if (!iface->no_dynamic_dhcp || l) {
1028 /* Create new binding */
1029 a = alloc_assignment(0);
1031 syslog(LOG_ERR, "Failed to alloc assignment on interface %s",
1035 memcpy(a->hwaddr, mac, sizeof(a->hwaddr));
1036 /* Set valid time to 0 for static lease indicating */
1037 /* infinite lifetime otherwise current time */
1038 a->valid_until = l ? 0 : now;
1039 a->dhcp_free_cb = dhcpv4_free_assignment;
1041 a->flags = OAF_DHCPV4;
1042 a->addr = l ? l->ipaddr : INADDR_ANY;
1044 assigned = dhcpv4_assign(iface, a, reqaddr);
1047 a->flags |= OAF_STATIC;
1050 a->hostname = strdup(l->hostname);
1053 a->leasetime = l->leasetime;
1055 list_add(&a->lease_list, &l->assignments);
1059 } else if (((a->addr & iface->dhcpv4_mask.s_addr) !=
1060 (iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr)) &&
1061 !(a->flags & OAF_STATIC)) {
1062 list_del_init(&a->head);
1063 a->addr = INADDR_ANY;
1065 assigned = dhcpv4_assign(iface, a, reqaddr);
1069 uint32_t my_leasetime;
1072 my_leasetime = a->leasetime;
1074 my_leasetime = iface->dhcpv4_leasetime;
1076 if ((*leasetime == 0) || (my_leasetime < *leasetime))
1077 *leasetime = my_leasetime;
1079 if (msg == DHCPV4_MSG_DISCOVER) {
1080 a->flags &= ~OAF_BOUND;
1082 *incl_fr_opt = accept_fr_nonce;
1083 if (!(a->flags & OAF_STATIC))
1084 a->valid_until = now;
1086 if ((!(a->flags & OAF_STATIC) || !a->hostname) && hostname_len > 0) {
1087 a->hostname = realloc(a->hostname, hostname_len + 1);
1089 memcpy(a->hostname, hostname, hostname_len);
1090 a->hostname[hostname_len] = 0;
1092 if (odhcpd_valid_hostname(a->hostname))
1093 a->flags &= ~OAF_BROKEN_HOSTNAME;
1095 a->flags |= OAF_BROKEN_HOSTNAME;
1099 if (reqopts_len > 0) {
1100 a->reqopts = realloc(a->reqopts, reqopts_len + 1);
1102 memcpy(a->reqopts, reqopts, reqopts_len);
1103 a->reqopts[reqopts_len] = 0;
1107 if (!(a->flags & OAF_BOUND)) {
1108 a->accept_fr_nonce = accept_fr_nonce;
1109 *incl_fr_opt = accept_fr_nonce;
1110 odhcpd_urandom(a->key, sizeof(a->key));
1111 a->flags |= OAF_BOUND;
1113 *incl_fr_opt = false;
1115 if (!(a->flags & OAF_STATIC))
1116 a->valid_until = ((*leasetime == UINT32_MAX) ? 0 : (time_t)(now + *leasetime));
1118 } else if (!assigned && a) {
1119 /* Cleanup failed assignment */
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_ia_write_statefile();