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 void valid_until_cb(struct uloop_timeout
*event
);
42 static void handle_addrlist_change(struct interface
*iface
);
43 static void free_dhcpv4_assignment(struct dhcpv4_assignment
*a
);
44 static void dhcpv4_fr_start(struct dhcpv4_assignment
*a
);
45 static void dhcpv4_fr_stop(struct dhcpv4_assignment
*a
);
46 static void handle_dhcpv4(void *addr
, void *data
, size_t len
,
47 struct interface
*iface
, void *dest_addr
);
48 static struct dhcpv4_assignment
* dhcpv4_lease(struct interface
*iface
,
49 enum dhcpv4_msg msg
, const uint8_t *mac
, const uint32_t reqaddr
,
50 uint32_t *leasetime
, const char *hostname
, const size_t hostname_len
,
51 const bool accept_fr_nonce
, bool *incl_fr_opt
, uint32_t *fr_serverid
);
53 static struct netevent_handler dhcpv4_netevent_handler
= { .cb
= dhcpv4_netevent_cb
, };
54 static struct uloop_timeout valid_until_timeout
= {.cb
= valid_until_cb
};
55 static uint32_t serial
= 0;
57 struct odhcpd_ref_ip
{
58 struct list_head head
;
60 struct odhcpd_ipaddr addr
;
63 /* Create socket and register events */
66 uloop_timeout_set(&valid_until_timeout
, 1000);
67 netlink_add_netevent_handler(&dhcpv4_netevent_handler
);
72 int dhcpv4_setup_interface(struct interface
*iface
, bool enable
)
76 if (iface
->dhcpv4_event
.uloop
.fd
> 0) {
77 uloop_fd_delete(&iface
->dhcpv4_event
.uloop
);
78 close(iface
->dhcpv4_event
.uloop
.fd
);
79 iface
->dhcpv4_event
.uloop
.fd
= -1;
82 if (iface
->dhcpv4
&& enable
) {
83 struct sockaddr_in bind_addr
= {AF_INET
, htons(DHCPV4_SERVER_PORT
),
87 if (!iface
->dhcpv4_assignments
.next
)
88 INIT_LIST_HEAD(&iface
->dhcpv4_assignments
);
90 if (!iface
->dhcpv4_fr_ips
.next
)
91 INIT_LIST_HEAD(&iface
->dhcpv4_fr_ips
);
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
))) {
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
))) {
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
))) {
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
))) {
140 syslog(LOG_ERR
, "setsockopt(SO_BINDTODEVICE): %m");
145 if (bind(iface
->dhcpv4_event
.uloop
.fd
, (struct sockaddr
*)&bind_addr
, sizeof(bind_addr
))) {
146 syslog(LOG_ERR
, "bind(): %m");
151 if (setup_dhcpv4_addresses(iface
) < 0) {
156 iface
->dhcpv4_event
.handle_dgram
= handle_dhcpv4
;
157 odhcpd_register(&iface
->dhcpv4_event
);
159 update_static_assignments(iface
);
160 } else if (iface
->dhcpv4_assignments
.next
) {
161 while (!list_empty(&iface
->dhcpv4_assignments
))
162 free_dhcpv4_assignment(list_first_entry(&iface
->dhcpv4_assignments
,
163 struct dhcpv4_assignment
, head
));
167 if (ret
< 0 && iface
->dhcpv4_event
.uloop
.fd
> 0) {
168 close(iface
->dhcpv4_event
.uloop
.fd
);
169 iface
->dhcpv4_event
.uloop
.fd
= -1;
176 static void dhcpv4_netevent_cb(unsigned long event
, struct netevent_handler_info
*info
)
178 struct interface
*iface
= info
->iface
;
180 if (!iface
|| iface
->dhcpv4
== MODE_DISABLED
)
184 case NETEV_IFINDEX_CHANGE
:
185 dhcpv4_setup_interface(iface
, true);
187 case NETEV_ADDRLIST_CHANGE
:
188 handle_addrlist_change(iface
);
195 static struct dhcpv4_assignment
*find_assignment_by_hwaddr(struct interface
*iface
, const uint8_t *hwaddr
)
197 struct dhcpv4_assignment
*a
;
199 list_for_each_entry(a
, &iface
->dhcpv4_assignments
, head
)
200 if (!memcmp(a
->hwaddr
, hwaddr
, 6))
206 static struct dhcpv4_assignment
*find_assignment_by_addr(struct interface
*iface
, const uint32_t addr
)
208 struct dhcpv4_assignment
*a
;
210 list_for_each_entry(a
, &iface
->dhcpv4_assignments
, head
)
217 static int setup_dhcpv4_addresses(struct interface
*iface
)
219 iface
->dhcpv4_start_ip
.s_addr
= INADDR_ANY
;
220 iface
->dhcpv4_end_ip
.s_addr
= INADDR_ANY
;
221 iface
->dhcpv4_local
.s_addr
= INADDR_ANY
;
222 iface
->dhcpv4_bcast
.s_addr
= INADDR_ANY
;
223 iface
->dhcpv4_mask
.s_addr
= INADDR_ANY
;
226 if (iface
->dhcpv4_start
.s_addr
& htonl(0xffff0000) ||
227 iface
->dhcpv4_end
.s_addr
& htonl(0xffff0000) ||
228 ntohl(iface
->dhcpv4_start
.s_addr
) > ntohl(iface
->dhcpv4_end
.s_addr
)) {
229 syslog(LOG_ERR
, "invalid DHCP range for %s", iface
->name
);
233 if (!iface
->addr4_len
) {
234 syslog(LOG_WARNING
, "no network(s) available on %s", iface
->name
);
238 uint32_t start
= ntohl(iface
->dhcpv4_start
.s_addr
);
239 uint32_t end
= ntohl(iface
->dhcpv4_end
.s_addr
);
241 for (size_t i
= 0; i
< iface
->addr4_len
&& start
&& end
; i
++) {
242 struct in_addr
*addr
= &iface
->addr4
[i
].addr
.in
;
245 odhcpd_bitlen2netmask(false, iface
->addr4
[i
].prefix
, &mask
);
246 if ((start
& ntohl(~mask
.s_addr
)) == start
&&
247 (end
& ntohl(~mask
.s_addr
)) == end
) {
248 iface
->dhcpv4_start_ip
.s_addr
= htonl(start
) |
249 (addr
->s_addr
& mask
.s_addr
);
250 iface
->dhcpv4_end_ip
.s_addr
= htonl(end
) |
251 (addr
->s_addr
& mask
.s_addr
);
252 iface
->dhcpv4_local
= *addr
;
253 iface
->dhcpv4_bcast
= iface
->addr4
[i
].broadcast
;
254 iface
->dhcpv4_mask
= mask
;
259 /* Don't allocate IP range for subnets bigger than 28 */
260 if (iface
->addr4
[0].prefix
> 28) {
261 syslog(LOG_WARNING
, "auto allocation of DHCP range fails on %s", iface
->name
);
265 iface
->dhcpv4_local
= iface
->addr4
[0].addr
.in
;
266 iface
->dhcpv4_bcast
= iface
->addr4
[0].broadcast
;
267 odhcpd_bitlen2netmask(false, iface
->addr4
[0].prefix
, &iface
->dhcpv4_mask
);
268 end
= start
= iface
->dhcpv4_local
.s_addr
& iface
->dhcpv4_mask
.s_addr
;
270 /* Auto allocate ranges */
271 if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffff00) {
272 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(100);
273 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(250);
274 } else if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffffc0) {
275 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(10);
276 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(60);
277 } else if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffffe0) {
278 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(10);
279 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(30);
281 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(3);
282 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(12);
288 static void update_static_assignments(struct interface
*iface
)
290 struct dhcpv4_assignment
*a
, *c
;
292 /* Cleanup static entries not belonging to the network */
293 list_for_each_entry_safe(a
, c
, &iface
->dhcpv4_assignments
, head
) {
294 if ((a
->flags
& OAF_STATIC
) &&
295 ((a
->addr
& iface
->dhcpv4_mask
.s_addr
) !=
296 (iface
->dhcpv4_start
.s_addr
& iface
->dhcpv4_mask
.s_addr
)))
297 free_dhcpv4_assignment(a
);
300 /* Parse static entries */
302 list_for_each_entry(lease
, &leases
, head
) {
303 if ((iface
->dhcpv4_start_ip
.s_addr
& iface
->dhcpv4_mask
.s_addr
) !=
304 (lease
->ipaddr
.s_addr
& iface
->dhcpv4_mask
.s_addr
)) {
308 a
= find_assignment_by_hwaddr(iface
, lease
->mac
.ether_addr_octet
);
311 /* Check if there's an assignment with the specified IP address */
312 if (find_assignment_by_addr(iface
, lease
->ipaddr
.s_addr
))
315 /* Construct entry */
316 a
= calloc(1, sizeof(*a
));
318 syslog(LOG_ERR
, "Calloc failed for static lease on interface %s",
322 memcpy(a
->hwaddr
, lease
->mac
.ether_addr_octet
, sizeof(a
->hwaddr
));
325 a
->leasetime
= lease
->dhcpv4_leasetime
;
327 a
->addr
= lease
->ipaddr
.s_addr
;
328 /* Static assignment */
329 a
->flags
|= OAF_STATIC
;
333 if (lease
->hostname
[0]) {
335 a
->hostname
= strdup(lease
->hostname
);
338 /* Assign to all interfaces */
339 list_for_each_entry(c
, &iface
->dhcpv4_assignments
, head
) {
340 if (ntohl(c
->addr
) > ntohl(a
->addr
)) {
341 list_add_tail(&a
->head
, &c
->head
);
346 if (&c
->head
== &iface
->dhcpv4_assignments
)
347 list_add(&a
->head
, &iface
->dhcpv4_assignments
);
351 static void inc_ref_cnt_ip(struct odhcpd_ref_ip
**ptr
, struct odhcpd_ref_ip
*ip
)
357 static void decr_ref_cnt_ip(struct odhcpd_ref_ip
**ptr
, struct interface
*iface
)
359 struct odhcpd_ref_ip
*ip
= *ptr
;
361 if (--ip
->ref_cnt
== 0) {
362 netlink_setup_addr(&ip
->addr
, iface
->ifindex
, false, false);
371 static bool leases_require_fr(struct interface
*iface
, struct odhcpd_ipaddr
*addr
,
374 struct dhcpv4_assignment
*a
= NULL
;
375 struct odhcpd_ref_ip
*fr_ip
= NULL
;
377 list_for_each_entry(a
, &iface
->dhcpv4_assignments
, head
) {
378 if ((a
->accept_fr_nonce
|| iface
->dhcpv4_forcereconf
) &&
380 ((a
->addr
& mask
) == (addr
->addr
.in
.s_addr
& mask
))) {
382 fr_ip
= calloc(1, sizeof(*fr_ip
));
386 list_add(&fr_ip
->head
, &iface
->dhcpv4_fr_ips
);
389 inc_ref_cnt_ip(&a
->fr_ip
, fr_ip
);
393 return fr_ip
? true : false;
396 static void valid_until_cb(struct uloop_timeout
*event
)
398 time_t now
= odhcpd_time();
399 struct interface
*iface
;
400 list_for_each_entry(iface
, &interfaces
, head
) {
401 if (iface
->dhcpv4
!= MODE_SERVER
|| iface
->dhcpv4_assignments
.next
== NULL
)
404 struct dhcpv4_assignment
*a
, *n
;
405 list_for_each_entry_safe(a
, n
, &iface
->dhcpv4_assignments
, head
) {
406 if (!INFINITE_VALID(a
->valid_until
) && a
->valid_until
< now
)
407 free_dhcpv4_assignment(a
);
410 uloop_timeout_set(event
, 1000);
413 static void handle_addrlist_change(struct interface
*iface
)
415 struct odhcpd_ipaddr ip
;
416 struct odhcpd_ref_ip
*a
;
417 struct dhcpv4_assignment
*c
;
418 uint32_t mask
= iface
->dhcpv4_mask
.s_addr
;
420 memset(&ip
, 0, sizeof(ip
));
421 ip
.addr
.in
= iface
->dhcpv4_local
;
422 ip
.prefix
= odhcpd_netmask2bitlen(false, &iface
->dhcpv4_mask
);
423 ip
.broadcast
= iface
->dhcpv4_bcast
;
425 setup_dhcpv4_addresses(iface
);
427 if ((ip
.addr
.in
.s_addr
& mask
) ==
428 (iface
->dhcpv4_local
.s_addr
& iface
->dhcpv4_mask
.s_addr
))
431 if (ip
.addr
.in
.s_addr
&& !leases_require_fr(iface
, &ip
, mask
))
434 if (iface
->dhcpv4_local
.s_addr
== INADDR_ANY
|| list_empty(&iface
->dhcpv4_fr_ips
))
437 a
= list_first_entry(&iface
->dhcpv4_fr_ips
, struct odhcpd_ref_ip
, head
);
439 if (netlink_setup_addr(&a
->addr
, iface
->ifindex
, false, true)) {
440 syslog(LOG_ERR
, "Failed to add ip address");
444 list_for_each_entry(c
, &iface
->dhcpv4_assignments
, head
) {
445 if ((c
->flags
& OAF_BOUND
) && c
->fr_ip
&& !c
->fr_cnt
) {
446 if (c
->accept_fr_nonce
|| iface
->dhcpv4_forcereconf
)
454 static char *dhcpv4_msg_to_string(uint8_t reqmsg
)
457 case (DHCPV4_MSG_DISCOVER
):
458 return "DHCPV4_MSG_DISCOVER";
459 case (DHCPV4_MSG_OFFER
):
460 return "DHCPV4_MSG_OFFER";
461 case (DHCPV4_MSG_REQUEST
):
462 return "DHCPV4_MSG_REQUEST";
463 case (DHCPV4_MSG_DECLINE
):
464 return "DHCPV4_MSG_DECLINE";
465 case (DHCPV4_MSG_ACK
):
466 return "DHCPV4_MSG_ACK";
467 case (DHCPV4_MSG_NAK
):
468 return "DHCPV4_MSG_NAK";
469 case (DHCPV4_MSG_RELEASE
):
470 return "DHCPV4_MSG_RELEASE";
471 case (DHCPV4_MSG_INFORM
):
472 return "DHCPV4_MSG_INFORM";
473 case (DHCPV4_MSG_FORCERENEW
):
474 return "DHCPV4_MSG_FORCERENEW";
480 static void free_dhcpv4_assignment(struct dhcpv4_assignment
*a
)
492 static void dhcpv4_put(struct dhcpv4_message
*msg
, uint8_t **cookie
,
493 uint8_t type
, uint8_t len
, const void *data
)
495 uint8_t *c
= *cookie
;
496 uint8_t *end
= (uint8_t *)msg
+ sizeof(*msg
);
498 if (*cookie
+ 2 + len
> end
)
503 memcpy(c
, data
, len
);
508 static void dhcpv4_fr_send(struct dhcpv4_assignment
*a
)
510 struct dhcpv4_message fr_msg
= {
511 .op
= DHCPV4_BOOTREPLY
,
517 .ciaddr
= {INADDR_ANY
},
518 .yiaddr
= {INADDR_ANY
},
519 .siaddr
= {INADDR_ANY
},
520 .giaddr
= {INADDR_ANY
},
525 struct dhcpv4_auth_forcerenew
*auth_o
, auth
= {
529 .replay
= {htonl(time(NULL
)), htonl(++serial
)},
533 struct interface
*iface
= a
->iface
;
535 odhcpd_urandom(&fr_msg
.xid
, sizeof(fr_msg
.xid
));
536 memcpy(fr_msg
.chaddr
, a
->hwaddr
, fr_msg
.hlen
);
538 fr_msg
.options
[0] = 0x63;
539 fr_msg
.options
[1] = 0x82;
540 fr_msg
.options
[2] = 0x53;
541 fr_msg
.options
[3] = 0x63;
543 uint8_t *cookie
= &fr_msg
.options
[4];
544 uint8_t msg
= DHCPV4_MSG_FORCERENEW
;
546 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_MESSAGE
, 1, &msg
);
547 if (a
->accept_fr_nonce
) {
548 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_AUTHENTICATION
, sizeof(auth
), &auth
);
549 auth_o
= (struct dhcpv4_auth_forcerenew
*)(cookie
- sizeof(auth
));
550 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_END
, 0, NULL
);
553 uint8_t secretbytes
[64];
554 memset(secretbytes
, 0, sizeof(secretbytes
));
555 memcpy(secretbytes
, a
->key
, sizeof(a
->key
));
557 for (size_t i
= 0; i
< sizeof(secretbytes
); ++i
)
558 secretbytes
[i
] ^= 0x36;
561 md5_hash(secretbytes
, sizeof(secretbytes
), &md5
);
562 md5_hash(&fr_msg
, sizeof(fr_msg
), &md5
);
563 md5_end(auth_o
->key
, &md5
);
565 for (size_t i
= 0; i
< sizeof(secretbytes
); ++i
) {
566 secretbytes
[i
] ^= 0x36;
567 secretbytes
[i
] ^= 0x5c;
571 md5_hash(secretbytes
, sizeof(secretbytes
), &md5
);
572 md5_hash(auth_o
->key
, sizeof(auth_o
->key
), &md5
);
573 md5_end(auth_o
->key
, &md5
);
575 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_SERVERID
, 4,
576 &a
->fr_ip
->addr
.addr
.in
.s_addr
);
577 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_END
, 0, NULL
);
580 struct sockaddr_in dest
;
581 memset(&dest
, 0, sizeof(dest
));
582 dest
.sin_family
= AF_INET
;
583 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
584 dest
.sin_addr
.s_addr
= a
->addr
;
586 syslog(LOG_WARNING
, "sending %s to %02x:%02x:%02x:%02x:%02x:%02x - %s",
587 dhcpv4_msg_to_string(msg
),
588 a
->hwaddr
[0], a
->hwaddr
[1], a
->hwaddr
[2],
589 a
->hwaddr
[3], a
->hwaddr
[4], a
->hwaddr
[5],
590 inet_ntoa(dest
.sin_addr
));
592 sendto(iface
->dhcpv4_event
.uloop
.fd
, &fr_msg
, sizeof(fr_msg
),
593 MSG_DONTWAIT
, (struct sockaddr
*)&dest
, sizeof(dest
));
596 static void dhcpv4_fr_timer(struct uloop_timeout
*event
)
598 struct dhcpv4_assignment
*a
= container_of(event
, struct dhcpv4_assignment
, fr_timer
);
600 if (a
->fr_cnt
> 0 && a
->fr_cnt
< 8) {
602 uloop_timeout_set(&a
->fr_timer
, 1000 << a
->fr_cnt
);
608 static void dhcpv4_fr_start(struct dhcpv4_assignment
*a
)
610 uloop_timeout_set(&a
->fr_timer
, 1000 << a
->fr_cnt
);
611 a
->fr_timer
.cb
= dhcpv4_fr_timer
;
617 static void dhcpv4_fr_stop(struct dhcpv4_assignment
*a
)
619 uloop_timeout_cancel(&a
->fr_timer
);
620 decr_ref_cnt_ip(&a
->fr_ip
, a
->iface
);
622 a
->fr_timer
.cb
= NULL
;
625 // Handler for DHCPv4 messages
626 static void handle_dhcpv4(void *addr
, void *data
, size_t len
,
627 struct interface
*iface
, _unused
void *dest_addr
)
632 struct dhcpv4_message
*req
= data
;
633 if (len
< offsetof(struct dhcpv4_message
, options
) + 4 ||
634 req
->op
!= DHCPV4_BOOTREQUEST
|| req
->hlen
!= 6)
638 syslog(LOG_NOTICE
, "Got DHCPv4 request");
640 if (!iface
->dhcpv4_start_ip
.s_addr
&& !iface
->dhcpv4_end_ip
.s_addr
) {
641 syslog(LOG_WARNING
, "No DHCP range available on %s", iface
->name
);
645 int sock
= iface
->dhcpv4_event
.uloop
.fd
;
647 struct dhcpv4_message reply
= {
648 .op
= DHCPV4_BOOTREPLY
,
655 .ciaddr
= {INADDR_ANY
},
656 .giaddr
= req
->giaddr
,
657 .siaddr
= iface
->dhcpv4_local
,
659 memcpy(reply
.chaddr
, req
->chaddr
, sizeof(reply
.chaddr
));
661 reply
.options
[0] = 0x63;
662 reply
.options
[1] = 0x82;
663 reply
.options
[2] = 0x53;
664 reply
.options
[3] = 0x63;
666 uint8_t *cookie
= &reply
.options
[4];
667 uint8_t reqmsg
= DHCPV4_MSG_REQUEST
;
668 uint8_t msg
= DHCPV4_MSG_ACK
;
670 uint32_t reqaddr
= INADDR_ANY
;
671 uint32_t leasetime
= 0;
672 size_t hostname_len
= 0;
674 bool accept_fr_nonce
= false;
675 bool incl_fr_opt
= false;
677 uint8_t *start
= &req
->options
[4];
678 uint8_t *end
= ((uint8_t*)data
) + len
;
679 struct dhcpv4_option
*opt
;
680 dhcpv4_for_each_option(start
, end
, opt
) {
681 if (opt
->type
== DHCPV4_OPT_MESSAGE
&& opt
->len
== 1)
682 reqmsg
= opt
->data
[0];
683 else if (opt
->type
== DHCPV4_OPT_HOSTNAME
&& opt
->len
> 0) {
684 hostname_len
= opt
->len
;
685 memcpy(hostname
, opt
->data
, hostname_len
);
686 hostname
[hostname_len
] = 0;
687 } else if (opt
->type
== DHCPV4_OPT_IPADDRESS
&& opt
->len
== 4)
688 memcpy(&reqaddr
, opt
->data
, 4);
689 else if (opt
->type
== DHCPV4_OPT_SERVERID
&& opt
->len
== 4) {
690 if (memcmp(opt
->data
, &iface
->dhcpv4_local
, 4))
692 } else if (iface
->filter_class
&& opt
->type
== DHCPV4_OPT_USER_CLASS
) {
693 uint8_t *c
= opt
->data
, *cend
= &opt
->data
[opt
->len
];
694 for (; c
< cend
&& &c
[*c
] < cend
; c
= &c
[1 + *c
]) {
695 size_t elen
= strlen(iface
->filter_class
);
696 if (*c
== elen
&& !memcmp(&c
[1], iface
->filter_class
, elen
))
697 return; // Ignore from homenet
699 } else if (opt
->type
== DHCPV4_OPT_LEASETIME
&& opt
->len
== 4)
700 memcpy(&leasetime
, opt
->data
, 4);
701 else if (opt
->type
== DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE
&& opt
->len
> 0) {
702 for (uint8_t i
= 0; i
< opt
->len
; i
++) {
703 if (opt
->data
[i
] == 1) {
704 accept_fr_nonce
= true;
712 if (reqmsg
!= DHCPV4_MSG_DISCOVER
&& reqmsg
!= DHCPV4_MSG_REQUEST
&&
713 reqmsg
!= DHCPV4_MSG_INFORM
&& reqmsg
!= DHCPV4_MSG_DECLINE
&&
714 reqmsg
!= DHCPV4_MSG_RELEASE
)
717 struct dhcpv4_assignment
*lease
= NULL
;
718 uint32_t serverid
= iface
->dhcpv4_local
.s_addr
;
719 uint32_t fr_serverid
= INADDR_ANY
;
721 if (reqmsg
!= DHCPV4_MSG_INFORM
)
722 lease
= dhcpv4_lease(iface
, reqmsg
, req
->chaddr
, reqaddr
,
723 &leasetime
, hostname
, hostname_len
,
724 accept_fr_nonce
, &incl_fr_opt
, &fr_serverid
);
727 if (reqmsg
== DHCPV4_MSG_REQUEST
)
728 msg
= DHCPV4_MSG_NAK
;
729 else if (reqmsg
== DHCPV4_MSG_DISCOVER
)
731 } else if (reqmsg
== DHCPV4_MSG_DISCOVER
)
732 msg
= DHCPV4_MSG_OFFER
;
733 else if (reqmsg
== DHCPV4_MSG_REQUEST
&&
734 ((reqaddr
&& reqaddr
!= lease
->addr
) ||
735 (req
->ciaddr
.s_addr
&& req
->ciaddr
.s_addr
!= lease
->addr
))) {
736 msg
= DHCPV4_MSG_NAK
;
738 * DHCP client requested an IP which we can't offer to him. Probably the
739 * client changed the network or the network has been changed. The reply
740 * type is set to DHCPV4_MSG_NAK, because the client should not use that IP.
742 * For modern devices we build an answer that includes a valid IP, like
743 * a DHCPV4_MSG_ACK. The client will use that IP and doesn't need to
744 * perform additional DHCP round trips.
750 * Buggy clients do serverid checking in nack messages; therefore set the
751 * serverid in nack messages triggered by a previous force renew equal to
752 * the server id in use at that time by the server
756 serverid
= fr_serverid
;
758 if (req
->ciaddr
.s_addr
&&
759 ((iface
->dhcpv4_start_ip
.s_addr
& iface
->dhcpv4_mask
.s_addr
) !=
760 (req
->ciaddr
.s_addr
& iface
->dhcpv4_mask
.s_addr
)))
761 req
->ciaddr
.s_addr
= INADDR_ANY
;
764 syslog(LOG_WARNING
, "received %s from %02x:%02x:%02x:%02x:%02x:%02x",
765 dhcpv4_msg_to_string(reqmsg
),
766 req
->chaddr
[0],req
->chaddr
[1],req
->chaddr
[2],
767 req
->chaddr
[3],req
->chaddr
[4],req
->chaddr
[5]);
770 if (reqmsg
== DHCPV4_MSG_RELEASE
)
771 ubus_bcast_dhcp_event("dhcp.release", req
->chaddr
, req
->hlen
,
772 &req
->ciaddr
, hostname
, iface
->ifname
);
774 if (reqmsg
== DHCPV4_MSG_DECLINE
|| reqmsg
== DHCPV4_MSG_RELEASE
)
777 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_MESSAGE
, 1, &msg
);
778 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_SERVERID
, 4, &serverid
);
783 reply
.yiaddr
.s_addr
= lease
->addr
;
785 val
= htonl(leasetime
);
786 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_LEASETIME
, 4, &val
);
788 if (leasetime
!= UINT32_MAX
) {
789 val
= htonl(500 * leasetime
/ 1000);
790 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_RENEW
, 4, &val
);
792 val
= htonl(875 * leasetime
/ 1000);
793 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_REBIND
, 4, &val
);
796 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_NETMASK
, 4,
797 &iface
->dhcpv4_mask
.s_addr
);
800 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_HOSTNAME
,
801 strlen(lease
->hostname
), lease
->hostname
);
803 if (iface
->dhcpv4_bcast
.s_addr
!= INADDR_ANY
)
804 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_BROADCAST
, 4, &iface
->dhcpv4_bcast
);
807 if (reqmsg
== DHCPV4_MSG_REQUEST
) {
808 struct dhcpv4_auth_forcerenew auth
= {
812 .replay
= {htonl(time(NULL
)), htonl(++serial
)},
817 memcpy(auth
.key
, lease
->key
, sizeof(auth
.key
));
818 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_AUTHENTICATION
, sizeof(auth
), &auth
);
821 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE
,
829 memset(&ifr
, 0, sizeof(ifr
));
830 strncpy(ifr
.ifr_name
, iface
->ifname
, sizeof(ifr
.ifr_name
) - 1);
832 if (!ioctl(sock
, SIOCGIFMTU
, &ifr
)) {
833 uint16_t mtu
= htons(ifr
.ifr_mtu
);
834 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_MTU
, 2, &mtu
);
837 if (iface
->search
&& iface
->search_len
<= 255)
838 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_SEARCH_DOMAIN
,
839 iface
->search_len
, iface
->search
);
840 else if (!res_init() && _res
.dnsrch
[0] && _res
.dnsrch
[0][0]) {
841 uint8_t search_buf
[256];
842 int len
= dn_comp(_res
.dnsrch
[0], search_buf
,
843 sizeof(search_buf
), NULL
, NULL
);
845 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_SEARCH_DOMAIN
,
849 if (iface
->dhcpv4_router_cnt
== 0)
850 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_ROUTER
, 4, &iface
->dhcpv4_local
);
852 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_ROUTER
,
853 4 * iface
->dhcpv4_router_cnt
, iface
->dhcpv4_router
);
856 if (iface
->dhcpv4_dns_cnt
== 0)
857 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_DNSSERVER
, 4, &iface
->dhcpv4_local
);
859 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_DNSSERVER
,
860 4 * iface
->dhcpv4_dns_cnt
, iface
->dhcpv4_dns
);
863 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_END
, 0, NULL
);
865 struct sockaddr_in dest
= *((struct sockaddr_in
*)addr
);
866 if (req
->giaddr
.s_addr
) {
868 * relay agent is configured, send reply to the agent
870 dest
.sin_addr
= req
->giaddr
;
871 dest
.sin_port
= htons(DHCPV4_SERVER_PORT
);
872 } else if (req
->ciaddr
.s_addr
&& req
->ciaddr
.s_addr
!= dest
.sin_addr
.s_addr
) {
874 * client has existing configuration (ciaddr is set) AND this address is
875 * not the address it used for the dhcp message
877 dest
.sin_addr
= req
->ciaddr
;
878 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
879 } else if ((ntohs(req
->flags
) & DHCPV4_FLAG_BROADCAST
) ||
880 req
->hlen
!= reply
.hlen
|| !reply
.yiaddr
.s_addr
) {
882 * client requests a broadcast reply OR we can't offer an IP
884 dest
.sin_addr
.s_addr
= INADDR_BROADCAST
;
885 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
886 } else if (!req
->ciaddr
.s_addr
&& msg
== DHCPV4_MSG_NAK
) {
888 * client has no previous configuration -> no IP, so we need to reply
889 * with a broadcast packet
891 dest
.sin_addr
.s_addr
= INADDR_BROADCAST
;
892 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
895 * send reply to the newly (in this proccess) allocated IP
897 dest
.sin_addr
= reply
.yiaddr
;
898 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
900 struct arpreq arp
= {.arp_flags
= ATF_COM
};
901 memcpy(arp
.arp_ha
.sa_data
, req
->chaddr
, 6);
902 memcpy(&arp
.arp_pa
, &dest
, sizeof(arp
.arp_pa
));
903 memcpy(arp
.arp_dev
, iface
->ifname
, sizeof(arp
.arp_dev
));
904 ioctl(sock
, SIOCSARP
, &arp
);
907 if (dest
.sin_addr
.s_addr
== INADDR_BROADCAST
)
908 /* reply goes to IP broadcast -> MAC broadcast */
909 syslog(LOG_WARNING
, "sending %s to ff:ff:ff:ff:ff:ff - %s",
910 dhcpv4_msg_to_string(msg
),
911 inet_ntoa(dest
.sin_addr
));
914 * reply is send directly to IP,
915 * MAC is assumed to be the same as the request
917 syslog(LOG_WARNING
, "sending %s to %02x:%02x:%02x:%02x:%02x:%02x - %s",
918 dhcpv4_msg_to_string(msg
),
919 req
->chaddr
[0],req
->chaddr
[1],req
->chaddr
[2],
920 req
->chaddr
[3],req
->chaddr
[4],req
->chaddr
[5],
921 inet_ntoa(dest
.sin_addr
));
923 sendto(sock
, &reply
, sizeof(reply
), MSG_DONTWAIT
,
924 (struct sockaddr
*)&dest
, sizeof(dest
));
927 if (msg
== DHCPV4_MSG_ACK
)
928 ubus_bcast_dhcp_event("dhcp.ack", req
->chaddr
, req
->hlen
, &reply
.yiaddr
,
929 hostname
, iface
->ifname
);
933 static bool dhcpv4_assign(struct interface
*iface
,
934 struct dhcpv4_assignment
*assign
, uint32_t raddr
)
936 uint32_t start
= ntohl(iface
->dhcpv4_start_ip
.s_addr
);
937 uint32_t end
= ntohl(iface
->dhcpv4_end_ip
.s_addr
);
938 uint32_t count
= end
- start
+ 1;
940 // try to assign the IP the client asked for
941 if (start
<= ntohl(raddr
) && ntohl(raddr
) <= end
&&
942 !find_assignment_by_addr(iface
, raddr
)) {
943 assign
->addr
= raddr
;
944 syslog(LOG_INFO
, "assigning the IP the client asked for: %u.%u.%u.%u",
945 ((uint8_t *)&assign
->addr
)[0],
946 ((uint8_t *)&assign
->addr
)[1],
947 ((uint8_t *)&assign
->addr
)[2],
948 ((uint8_t *)&assign
->addr
)[3]);
952 // Seed RNG with checksum of hwaddress
954 for (size_t i
= 0; i
< sizeof(assign
->hwaddr
); ++i
) {
955 // Knuth's multiplicative method
956 uint8_t o
= assign
->hwaddr
[i
];
957 seed
+= (o
*2654435761) % UINT32_MAX
;
962 uint32_t try = (((uint32_t)rand()) % count
) + start
;
964 if (list_empty(&iface
->dhcpv4_assignments
)) {
965 assign
->addr
= htonl(try);
966 syslog(LOG_INFO
, "assigning mapped IP (empty list): %u.%u.%u.%u",
967 ((uint8_t *)&assign
->addr
)[0],
968 ((uint8_t *)&assign
->addr
)[1],
969 ((uint8_t *)&assign
->addr
)[2],
970 ((uint8_t *)&assign
->addr
)[3]);
974 for (uint32_t i
= 0; i
< count
; ++i
) {
975 if (!find_assignment_by_addr(iface
, htonl(try))) {
976 /* test was successful: IP address is not assigned, assign it */
977 assign
->addr
= htonl(try);
978 syslog(LOG_DEBUG
, "assigning mapped IP: %u.%u.%u.%u (try %u of %u)",
979 ((uint8_t *)&assign
->addr
)[0],
980 ((uint8_t *)&assign
->addr
)[1],
981 ((uint8_t *)&assign
->addr
)[2],
982 ((uint8_t *)&assign
->addr
)[3],
986 try = (((try - start
) + 1) % count
) + start
;
989 syslog(LOG_WARNING
, "can't assign any IP address -> address space is full");
994 static struct dhcpv4_assignment
* dhcpv4_lease(struct interface
*iface
,
995 enum dhcpv4_msg msg
, const uint8_t *mac
, const uint32_t reqaddr
,
996 uint32_t *leasetime
, const char *hostname
, const size_t hostname_len
,
997 const bool accept_fr_nonce
, bool *incl_fr_opt
, uint32_t *fr_serverid
)
999 struct dhcpv4_assignment
*a
= find_assignment_by_hwaddr(iface
, mac
);
1000 struct dhcpv4_assignment
*lease
= NULL
;
1001 time_t now
= odhcpd_time();
1003 if (a
&& (a
->flags
& OAF_BOUND
) && a
->fr_ip
) {
1004 *fr_serverid
= a
->fr_ip
->addr
.addr
.in
.s_addr
;
1008 if (msg
== DHCPV4_MSG_DISCOVER
|| msg
== DHCPV4_MSG_REQUEST
) {
1009 bool assigned
= !!a
;
1012 if (!iface
->no_dynamic_dhcp
) {
1013 /* Create new binding */
1014 a
= calloc(1, sizeof(*a
));
1016 syslog(LOG_ERR
, "Failed to calloc binding on interface %s",
1020 memcpy(a
->hwaddr
, mac
, sizeof(a
->hwaddr
));
1021 /* Don't consider new assignment as infinite */
1022 a
->valid_until
= now
;
1024 assigned
= dhcpv4_assign(iface
, a
, reqaddr
);
1027 list_add(&a
->head
, &iface
->dhcpv4_assignments
);
1030 } else if ((a
->addr
& iface
->dhcpv4_mask
.s_addr
) !=
1031 (iface
->dhcpv4_start_ip
.s_addr
& iface
->dhcpv4_mask
.s_addr
)) {
1034 assigned
= dhcpv4_assign(iface
, a
, reqaddr
);
1036 list_add(&a
->head
, &iface
->dhcpv4_assignments
);
1040 uint32_t my_leasetime
;
1043 my_leasetime
= a
->leasetime
;
1045 my_leasetime
= iface
->dhcpv4_leasetime
;
1047 if ((*leasetime
== 0) || (my_leasetime
< *leasetime
))
1048 *leasetime
= my_leasetime
;
1050 if (msg
== DHCPV4_MSG_DISCOVER
) {
1051 a
->flags
&= ~OAF_BOUND
;
1053 *incl_fr_opt
= accept_fr_nonce
;
1054 if (!(a
->flags
& OAF_STATIC
))
1055 a
->valid_until
= now
;
1057 if (hostname_len
> 0) {
1058 a
->hostname
= realloc(a
->hostname
, hostname_len
+ 1);
1060 memcpy(a
->hostname
, hostname
, hostname_len
);
1061 a
->hostname
[hostname_len
] = 0;
1065 if (!(a
->flags
& OAF_BOUND
)) {
1066 a
->accept_fr_nonce
= accept_fr_nonce
;
1067 *incl_fr_opt
= accept_fr_nonce
;
1068 odhcpd_urandom(a
->key
, sizeof(a
->key
));
1069 a
->flags
|= OAF_BOUND
;
1071 *incl_fr_opt
= false;
1073 if (!(a
->flags
& OAF_STATIC
))
1074 a
->valid_until
= ((*leasetime
== UINT32_MAX
) ? 0 : (time_t)(now
+ *leasetime
));
1076 } else if (!assigned
&& a
) {
1077 /* Cleanup failed assignment */
1078 free_dhcpv4_assignment(a
);
1084 } else if (msg
== DHCPV4_MSG_RELEASE
&& a
) {
1085 a
->flags
&= ~OAF_BOUND
;
1087 if (!(a
->flags
& OAF_STATIC
))
1088 a
->valid_until
= now
- 1;
1090 } else if (msg
== DHCPV4_MSG_DECLINE
&& a
) {
1091 a
->flags
&= ~OAF_BOUND
;
1093 if (!(a
->flags
& OAF_STATIC
)) {
1094 memset(a
->hwaddr
, 0, sizeof(a
->hwaddr
));
1095 a
->valid_until
= now
+ 3600; /* Block address for 1h */
1099 dhcpv6_write_statefile();