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 if (iface
->dhcpv4_event
.uloop
.fd
>= 0) {
81 uloop_fd_delete(&iface
->dhcpv4_event
.uloop
);
82 close(iface
->dhcpv4_event
.uloop
.fd
);
83 iface
->dhcpv4_event
.uloop
.fd
= -1;
86 if (iface
->dhcpv4
&& enable
) {
87 struct sockaddr_in bind_addr
= {AF_INET
, htons(DHCPV4_SERVER_PORT
),
91 iface
->dhcpv4_event
.uloop
.fd
= socket(AF_INET
, SOCK_DGRAM
| SOCK_CLOEXEC
, IPPROTO_UDP
);
92 if (iface
->dhcpv4_event
.uloop
.fd
< 0) {
93 syslog(LOG_ERR
, "socket(AF_INET): %m");
98 /* Basic IPv4 configuration */
99 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, SOL_SOCKET
, SO_REUSEADDR
,
100 &val
, sizeof(val
)) < 0) {
101 syslog(LOG_ERR
, "setsockopt(SO_REUSEADDR): %m");
106 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, SOL_SOCKET
, SO_BROADCAST
,
107 &val
, sizeof(val
)) < 0) {
108 syslog(LOG_ERR
, "setsockopt(SO_BROADCAST): %m");
113 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, IPPROTO_IP
, IP_PKTINFO
,
114 &val
, sizeof(val
)) < 0) {
115 syslog(LOG_ERR
, "setsockopt(IP_PKTINFO): %m");
120 val
= IPTOS_PREC_INTERNETCONTROL
;
121 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, IPPROTO_IP
, IP_TOS
,
122 &val
, sizeof(val
)) < 0) {
123 syslog(LOG_ERR
, "setsockopt(IP_TOS): %m");
128 val
= IP_PMTUDISC_DONT
;
129 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, IPPROTO_IP
, IP_MTU_DISCOVER
,
130 &val
, sizeof(val
)) < 0) {
131 syslog(LOG_ERR
, "setsockopt(IP_MTU_DISCOVER): %m");
136 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, SOL_SOCKET
, SO_BINDTODEVICE
,
137 iface
->ifname
, strlen(iface
->ifname
)) < 0) {
138 syslog(LOG_ERR
, "setsockopt(SO_BINDTODEVICE): %m");
143 if (bind(iface
->dhcpv4_event
.uloop
.fd
, (struct sockaddr
*)&bind_addr
,
144 sizeof(bind_addr
)) < 0) {
145 syslog(LOG_ERR
, "bind(): %m");
150 if (setup_dhcpv4_addresses(iface
) < 0) {
155 iface
->dhcpv4_event
.handle_dgram
= handle_dhcpv4
;
156 odhcpd_register(&iface
->dhcpv4_event
);
158 while (!list_empty(&iface
->dhcpv4_assignments
))
159 free_assignment(list_first_entry(&iface
->dhcpv4_assignments
,
160 struct dhcp_assignment
, head
));
164 if (ret
< 0 && iface
->dhcpv4_event
.uloop
.fd
>= 0) {
165 close(iface
->dhcpv4_event
.uloop
.fd
);
166 iface
->dhcpv4_event
.uloop
.fd
= -1;
173 static void dhcpv4_netevent_cb(unsigned long event
, struct netevent_handler_info
*info
)
175 struct interface
*iface
= info
->iface
;
177 if (!iface
|| iface
->dhcpv4
== MODE_DISABLED
)
181 case NETEV_IFINDEX_CHANGE
:
182 dhcpv4_setup_interface(iface
, true);
184 case NETEV_ADDRLIST_CHANGE
:
185 handle_addrlist_change(iface
);
192 static struct dhcp_assignment
*find_assignment_by_hwaddr(struct interface
*iface
, const uint8_t *hwaddr
)
194 struct dhcp_assignment
*a
;
196 list_for_each_entry(a
, &iface
->dhcpv4_assignments
, head
)
197 if (!memcmp(a
->hwaddr
, hwaddr
, 6))
203 static int setup_dhcpv4_addresses(struct interface
*iface
)
205 iface
->dhcpv4_start_ip
.s_addr
= INADDR_ANY
;
206 iface
->dhcpv4_end_ip
.s_addr
= INADDR_ANY
;
207 iface
->dhcpv4_local
.s_addr
= INADDR_ANY
;
208 iface
->dhcpv4_bcast
.s_addr
= INADDR_ANY
;
209 iface
->dhcpv4_mask
.s_addr
= INADDR_ANY
;
212 if (iface
->dhcpv4_start
.s_addr
& htonl(0xffff0000) ||
213 iface
->dhcpv4_end
.s_addr
& htonl(0xffff0000) ||
214 ntohl(iface
->dhcpv4_start
.s_addr
) > ntohl(iface
->dhcpv4_end
.s_addr
)) {
215 syslog(LOG_ERR
, "Invalid DHCP range for %s", iface
->name
);
219 if (!iface
->addr4_len
) {
220 syslog(LOG_ERR
, "No network(s) available on %s", iface
->name
);
224 uint32_t start
= ntohl(iface
->dhcpv4_start
.s_addr
);
225 uint32_t end
= ntohl(iface
->dhcpv4_end
.s_addr
);
227 for (size_t i
= 0; i
< iface
->addr4_len
&& start
&& end
; i
++) {
228 struct in_addr
*addr
= &iface
->addr4
[i
].addr
.in
;
231 if (addr_is_fr_ip(iface
, addr
))
234 odhcpd_bitlen2netmask(false, iface
->addr4
[i
].prefix
, &mask
);
235 if ((start
& ntohl(~mask
.s_addr
)) == start
&&
236 (end
& ntohl(~mask
.s_addr
)) == end
&&
237 end
< ntohl(~mask
.s_addr
)) { /* Exclude broadcast address */
238 iface
->dhcpv4_start_ip
.s_addr
= htonl(start
) |
239 (addr
->s_addr
& mask
.s_addr
);
240 iface
->dhcpv4_end_ip
.s_addr
= htonl(end
) |
241 (addr
->s_addr
& mask
.s_addr
);
242 iface
->dhcpv4_local
= *addr
;
243 iface
->dhcpv4_bcast
= iface
->addr4
[i
].broadcast
;
244 iface
->dhcpv4_mask
= mask
;
249 /* Don't allocate IP range for subnets bigger than 28 */
250 if (iface
->addr4
[0].prefix
> 28) {
251 syslog(LOG_ERR
, "Auto allocation of DHCP range fails on %s", iface
->name
);
255 iface
->dhcpv4_local
= iface
->addr4
[0].addr
.in
;
256 iface
->dhcpv4_bcast
= iface
->addr4
[0].broadcast
;
257 odhcpd_bitlen2netmask(false, iface
->addr4
[0].prefix
, &iface
->dhcpv4_mask
);
258 end
= start
= iface
->dhcpv4_local
.s_addr
& iface
->dhcpv4_mask
.s_addr
;
260 /* Auto allocate ranges */
261 if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffff00) { /* /24, 150 of 256, [100..249] */
262 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(100);
263 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(100 + 150 - 1);
264 } else if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffff80) { /* /25, 100 of 128, [20..119] */
265 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(20);
266 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(20 + 100 - 1);
267 } else if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffffc0) { /* /26, 50 of 64, [10..59] */
268 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(10);
269 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(10 + 50 - 1);
270 } else if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffffe0) { /* /27, 20 of 32, [10..29] */
271 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(10);
272 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(10 + 20 - 1);
273 } else { /* /28, 10 of 16, [3..12] */
274 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(3);
275 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(3 + 10 - 1);
281 static void inc_ref_cnt_ip(struct odhcpd_ref_ip
**ptr
, struct odhcpd_ref_ip
*ip
)
287 static void decr_ref_cnt_ip(struct odhcpd_ref_ip
**ptr
, struct interface
*iface
)
289 struct odhcpd_ref_ip
*ip
= *ptr
;
291 if (--ip
->ref_cnt
== 0) {
292 netlink_setup_addr(&ip
->addr
, iface
->ifindex
, false, false);
301 static bool addr_is_fr_ip(struct interface
*iface
, struct in_addr
*addr
)
303 struct odhcpd_ref_ip
*p
;
305 list_for_each_entry(p
, &iface
->dhcpv4_fr_ips
, head
) {
306 if (addr
->s_addr
== p
->addr
.addr
.in
.s_addr
)
313 static bool leases_require_fr(struct interface
*iface
, struct odhcpd_ipaddr
*addr
,
316 struct dhcp_assignment
*a
= NULL
;
317 struct odhcpd_ref_ip
*fr_ip
= NULL
;
319 list_for_each_entry(a
, &iface
->dhcpv4_assignments
, head
) {
320 if ((a
->accept_fr_nonce
|| iface
->dhcpv4_forcereconf
) &&
322 ((a
->addr
& mask
) == (addr
->addr
.in
.s_addr
& mask
))) {
324 fr_ip
= calloc(1, sizeof(*fr_ip
));
328 list_add(&fr_ip
->head
, &iface
->dhcpv4_fr_ips
);
331 inc_ref_cnt_ip(&a
->fr_ip
, fr_ip
);
335 return fr_ip
? true : false;
338 static void valid_until_cb(struct uloop_timeout
*event
)
340 struct interface
*iface
;
341 time_t now
= odhcpd_time();
343 avl_for_each_element(&interfaces
, iface
, avl
) {
344 struct dhcp_assignment
*a
, *n
;
346 if (iface
->dhcpv4
!= MODE_SERVER
)
349 list_for_each_entry_safe(a
, n
, &iface
->dhcpv4_assignments
, head
) {
350 if (!INFINITE_VALID(a
->valid_until
) && a
->valid_until
< now
)
354 uloop_timeout_set(event
, 1000);
357 static void handle_addrlist_change(struct interface
*iface
)
359 struct odhcpd_ipaddr ip
;
360 struct odhcpd_ref_ip
*a
;
361 struct dhcp_assignment
*c
;
362 uint32_t mask
= iface
->dhcpv4_mask
.s_addr
;
364 memset(&ip
, 0, sizeof(ip
));
365 ip
.addr
.in
= iface
->dhcpv4_local
;
366 ip
.prefix
= odhcpd_netmask2bitlen(false, &iface
->dhcpv4_mask
);
367 ip
.broadcast
= iface
->dhcpv4_bcast
;
369 setup_dhcpv4_addresses(iface
);
371 if ((ip
.addr
.in
.s_addr
& mask
) ==
372 (iface
->dhcpv4_local
.s_addr
& iface
->dhcpv4_mask
.s_addr
))
375 if (ip
.addr
.in
.s_addr
&& !leases_require_fr(iface
, &ip
, mask
))
378 if (iface
->dhcpv4_local
.s_addr
== INADDR_ANY
|| list_empty(&iface
->dhcpv4_fr_ips
))
381 a
= list_first_entry(&iface
->dhcpv4_fr_ips
, struct odhcpd_ref_ip
, head
);
383 if (netlink_setup_addr(&a
->addr
, iface
->ifindex
, false, true)) {
384 syslog(LOG_ERR
, "Failed to add ip address on %s", iface
->name
);
388 list_for_each_entry(c
, &iface
->dhcpv4_assignments
, head
) {
389 if ((c
->flags
& OAF_BOUND
) && c
->fr_ip
&& !c
->fr_cnt
) {
390 if (c
->accept_fr_nonce
|| iface
->dhcpv4_forcereconf
)
391 dhcpv4_fr_rand_delay(c
);
398 static char *dhcpv4_msg_to_string(uint8_t reqmsg
)
401 case (DHCPV4_MSG_DISCOVER
):
402 return "DHCPV4_MSG_DISCOVER";
403 case (DHCPV4_MSG_OFFER
):
404 return "DHCPV4_MSG_OFFER";
405 case (DHCPV4_MSG_REQUEST
):
406 return "DHCPV4_MSG_REQUEST";
407 case (DHCPV4_MSG_DECLINE
):
408 return "DHCPV4_MSG_DECLINE";
409 case (DHCPV4_MSG_ACK
):
410 return "DHCPV4_MSG_ACK";
411 case (DHCPV4_MSG_NAK
):
412 return "DHCPV4_MSG_NAK";
413 case (DHCPV4_MSG_RELEASE
):
414 return "DHCPV4_MSG_RELEASE";
415 case (DHCPV4_MSG_INFORM
):
416 return "DHCPV4_MSG_INFORM";
417 case (DHCPV4_MSG_FORCERENEW
):
418 return "DHCPV4_MSG_FORCERENEW";
424 static void dhcpv4_free_assignment(struct dhcp_assignment
*a
)
430 static void dhcpv4_put(struct dhcpv4_message
*msg
, uint8_t **cookie
,
431 uint8_t type
, uint8_t len
, const void *data
)
433 uint8_t *c
= *cookie
;
434 uint8_t *end
= (uint8_t *)msg
+ sizeof(*msg
);
435 bool tag_only
= type
== DHCPV4_OPT_PAD
|| type
== DHCPV4_OPT_END
;
436 int total_len
= tag_only
? 1 : 2 + len
;
438 if (*cookie
+ total_len
> end
)
441 *cookie
+= total_len
;
448 memcpy(c
, data
, len
);
451 static void dhcpv4_fr_send(struct dhcp_assignment
*a
)
453 struct dhcpv4_message fr_msg
= {
454 .op
= DHCPV4_BOOTREPLY
,
460 .ciaddr
= {INADDR_ANY
},
461 .yiaddr
= {INADDR_ANY
},
462 .siaddr
= {INADDR_ANY
},
463 .giaddr
= {INADDR_ANY
},
468 struct dhcpv4_auth_forcerenew
*auth_o
, auth
= {
472 .replay
= {htonl(time(NULL
)), htonl(++serial
)},
476 struct interface
*iface
= a
->iface
;
478 odhcpd_urandom(&fr_msg
.xid
, sizeof(fr_msg
.xid
));
479 memcpy(fr_msg
.chaddr
, a
->hwaddr
, fr_msg
.hlen
);
481 fr_msg
.options
[0] = 0x63;
482 fr_msg
.options
[1] = 0x82;
483 fr_msg
.options
[2] = 0x53;
484 fr_msg
.options
[3] = 0x63;
486 uint8_t *cookie
= &fr_msg
.options
[4];
487 uint8_t msg
= DHCPV4_MSG_FORCERENEW
;
489 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_MESSAGE
, 1, &msg
);
490 if (a
->accept_fr_nonce
) {
491 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_AUTHENTICATION
, sizeof(auth
), &auth
);
492 auth_o
= (struct dhcpv4_auth_forcerenew
*)(cookie
- sizeof(auth
));
493 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_END
, 0, NULL
);
496 uint8_t secretbytes
[64];
497 memset(secretbytes
, 0, sizeof(secretbytes
));
498 memcpy(secretbytes
, a
->key
, sizeof(a
->key
));
500 for (size_t i
= 0; i
< sizeof(secretbytes
); ++i
)
501 secretbytes
[i
] ^= 0x36;
504 md5_hash(secretbytes
, sizeof(secretbytes
), &md5
);
505 md5_hash(&fr_msg
, sizeof(fr_msg
), &md5
);
506 md5_end(auth_o
->key
, &md5
);
508 for (size_t i
= 0; i
< sizeof(secretbytes
); ++i
) {
509 secretbytes
[i
] ^= 0x36;
510 secretbytes
[i
] ^= 0x5c;
514 md5_hash(secretbytes
, sizeof(secretbytes
), &md5
);
515 md5_hash(auth_o
->key
, sizeof(auth_o
->key
), &md5
);
516 md5_end(auth_o
->key
, &md5
);
518 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_SERVERID
, 4,
519 &a
->fr_ip
->addr
.addr
.in
.s_addr
);
520 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_END
, 0, NULL
);
523 struct sockaddr_in dest
;
524 memset(&dest
, 0, sizeof(dest
));
525 dest
.sin_family
= AF_INET
;
526 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
527 dest
.sin_addr
.s_addr
= a
->addr
;
529 if (sendto(iface
->dhcpv4_event
.uloop
.fd
, &fr_msg
, PACKET_SIZE(&fr_msg
, cookie
),
530 MSG_DONTWAIT
, (struct sockaddr
*)&dest
, sizeof(dest
)) < 0)
531 syslog(LOG_ERR
, "Failed to send %s to %s - %s: %m", dhcpv4_msg_to_string(msg
),
532 odhcpd_print_mac(a
->hwaddr
, sizeof(a
->hwaddr
)), inet_ntoa(dest
.sin_addr
));
534 syslog(LOG_NOTICE
, "Sent %s to %s - %s", dhcpv4_msg_to_string(msg
),
535 odhcpd_print_mac(a
->hwaddr
, sizeof(a
->hwaddr
)), inet_ntoa(dest
.sin_addr
));
538 static void dhcpv4_fr_timer(struct uloop_timeout
*event
)
540 struct dhcp_assignment
*a
= container_of(event
, struct dhcp_assignment
, fr_timer
);
542 if (a
->fr_cnt
> 0 && a
->fr_cnt
< 8) {
544 uloop_timeout_set(&a
->fr_timer
, 1000 << a
->fr_cnt
);
550 static void dhcpv4_fr_start(struct dhcp_assignment
*a
)
552 uloop_timeout_set(&a
->fr_timer
, 1000 << a
->fr_cnt
);
553 a
->fr_timer
.cb
= dhcpv4_fr_timer
;
559 static void dhcpv4_fr_delay_timer(struct uloop_timeout
*event
)
561 struct dhcp_assignment
*a
= container_of(event
, struct dhcp_assignment
, fr_timer
);
562 struct interface
*iface
= a
->iface
;
564 (iface
->dhcpv4_event
.uloop
.fd
== -1 ? dhcpv4_fr_rand_delay(a
) : dhcpv4_fr_start(a
));
567 static void dhcpv4_fr_rand_delay(struct dhcp_assignment
*a
)
569 #define MIN_DELAY 500
573 odhcpd_urandom(&msecs
, sizeof(msecs
));
575 msecs
= labs(msecs
)%MAX_FUZZ
+ MIN_DELAY
;
577 uloop_timeout_set(&a
->fr_timer
, msecs
);
578 a
->fr_timer
.cb
= dhcpv4_fr_delay_timer
;
581 static void dhcpv4_fr_stop(struct dhcp_assignment
*a
)
583 uloop_timeout_cancel(&a
->fr_timer
);
584 decr_ref_cnt_ip(&a
->fr_ip
, a
->iface
);
586 a
->fr_timer
.cb
= NULL
;
589 /* Handler for DHCPv4 messages */
590 static void handle_dhcpv4(void *addr
, void *data
, size_t len
,
591 struct interface
*iface
, _unused
void *dest_addr
)
593 struct dhcpv4_message
*req
= data
;
598 if (len
< offsetof(struct dhcpv4_message
, options
) + 4 ||
599 req
->op
!= DHCPV4_BOOTREQUEST
|| req
->hlen
!= 6)
602 syslog(LOG_NOTICE
, "Got DHCPv4 request on %s", iface
->name
);
604 if (!iface
->dhcpv4_start_ip
.s_addr
&& !iface
->dhcpv4_end_ip
.s_addr
) {
605 syslog(LOG_ERR
, "No DHCP range available on %s", iface
->name
);
609 int sock
= iface
->dhcpv4_event
.uloop
.fd
;
611 struct dhcpv4_message reply
= {
612 .op
= DHCPV4_BOOTREPLY
,
619 .ciaddr
= {INADDR_ANY
},
620 .giaddr
= req
->giaddr
,
621 .siaddr
= iface
->dhcpv4_local
,
623 memcpy(reply
.chaddr
, req
->chaddr
, sizeof(reply
.chaddr
));
625 reply
.options
[0] = 0x63;
626 reply
.options
[1] = 0x82;
627 reply
.options
[2] = 0x53;
628 reply
.options
[3] = 0x63;
630 uint8_t *cookie
= &reply
.options
[4];
631 uint8_t reqmsg
= DHCPV4_MSG_REQUEST
;
632 uint8_t msg
= DHCPV4_MSG_ACK
;
634 uint32_t reqaddr
= INADDR_ANY
;
635 uint32_t leasetime
= 0;
636 size_t hostname_len
= 0;
637 size_t reqopts_len
= 0;
640 bool accept_fr_nonce
= false;
641 bool incl_fr_opt
= false;
643 uint8_t *start
= &req
->options
[4];
644 uint8_t *end
= ((uint8_t*)data
) + len
;
645 struct dhcpv4_option
*opt
;
646 dhcpv4_for_each_option(start
, end
, opt
) {
647 if (opt
->type
== DHCPV4_OPT_MESSAGE
&& opt
->len
== 1)
648 reqmsg
= opt
->data
[0];
649 else if (opt
->type
== DHCPV4_OPT_REQOPTS
&& opt
->len
> 0) {
650 reqopts_len
= opt
->len
;
651 memcpy(reqopts
, opt
->data
, reqopts_len
);
652 reqopts
[reqopts_len
] = 0;
653 } else if (opt
->type
== DHCPV4_OPT_HOSTNAME
&& opt
->len
> 0) {
654 hostname_len
= opt
->len
;
655 memcpy(hostname
, opt
->data
, hostname_len
);
656 hostname
[hostname_len
] = 0;
657 } else if (opt
->type
== DHCPV4_OPT_IPADDRESS
&& opt
->len
== 4)
658 memcpy(&reqaddr
, opt
->data
, 4);
659 else if (opt
->type
== DHCPV4_OPT_SERVERID
&& opt
->len
== 4) {
660 if (memcmp(opt
->data
, &iface
->dhcpv4_local
, 4))
662 } else if (iface
->filter_class
&& opt
->type
== DHCPV4_OPT_USER_CLASS
) {
663 uint8_t *c
= opt
->data
, *cend
= &opt
->data
[opt
->len
];
664 for (; c
< cend
&& &c
[*c
] < cend
; c
= &c
[1 + *c
]) {
665 size_t elen
= strlen(iface
->filter_class
);
666 if (*c
== elen
&& !memcmp(&c
[1], iface
->filter_class
, elen
))
667 return; // Ignore from homenet
669 } else if (opt
->type
== DHCPV4_OPT_LEASETIME
&& opt
->len
== 4)
670 memcpy(&leasetime
, opt
->data
, 4);
671 else if (opt
->type
== DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE
&& opt
->len
> 0) {
672 for (uint8_t i
= 0; i
< opt
->len
; i
++) {
673 if (opt
->data
[i
] == 1) {
674 accept_fr_nonce
= true;
682 if (reqmsg
!= DHCPV4_MSG_DISCOVER
&& reqmsg
!= DHCPV4_MSG_REQUEST
&&
683 reqmsg
!= DHCPV4_MSG_INFORM
&& reqmsg
!= DHCPV4_MSG_DECLINE
&&
684 reqmsg
!= DHCPV4_MSG_RELEASE
)
687 struct dhcp_assignment
*a
= NULL
;
688 uint32_t serverid
= iface
->dhcpv4_local
.s_addr
;
689 uint32_t fr_serverid
= INADDR_ANY
;
691 if (reqmsg
!= DHCPV4_MSG_INFORM
)
692 a
= dhcpv4_lease(iface
, reqmsg
, req
->chaddr
, reqaddr
,
693 &leasetime
, hostname
, hostname_len
,
694 accept_fr_nonce
, &incl_fr_opt
, &fr_serverid
,
695 reqopts
, reqopts_len
);
698 if (reqmsg
== DHCPV4_MSG_REQUEST
)
699 msg
= DHCPV4_MSG_NAK
;
700 else if (reqmsg
== DHCPV4_MSG_DISCOVER
)
702 } else if (reqmsg
== DHCPV4_MSG_DISCOVER
)
703 msg
= DHCPV4_MSG_OFFER
;
704 else if (reqmsg
== DHCPV4_MSG_REQUEST
&&
705 ((reqaddr
&& reqaddr
!= a
->addr
) ||
706 (req
->ciaddr
.s_addr
&& req
->ciaddr
.s_addr
!= a
->addr
))) {
707 msg
= DHCPV4_MSG_NAK
;
709 * DHCP client requested an IP which we can't offer to him. Probably the
710 * client changed the network or the network has been changed. The reply
711 * type is set to DHCPV4_MSG_NAK, because the client should not use that IP.
713 * For modern devices we build an answer that includes a valid IP, like
714 * a DHCPV4_MSG_ACK. The client will use that IP and doesn't need to
715 * perform additional DHCP round trips.
721 * Buggy clients do serverid checking in nack messages; therefore set the
722 * serverid in nack messages triggered by a previous force renew equal to
723 * the server id in use at that time by the server
727 serverid
= fr_serverid
;
729 if (req
->ciaddr
.s_addr
&&
730 ((iface
->dhcpv4_start_ip
.s_addr
& iface
->dhcpv4_mask
.s_addr
) !=
731 (req
->ciaddr
.s_addr
& iface
->dhcpv4_mask
.s_addr
)))
732 req
->ciaddr
.s_addr
= INADDR_ANY
;
735 syslog(LOG_NOTICE
, "Received %s from %s on %s", dhcpv4_msg_to_string(reqmsg
),
736 odhcpd_print_mac(req
->chaddr
, req
->hlen
), iface
->name
);
739 if (reqmsg
== DHCPV4_MSG_RELEASE
)
740 ubus_bcast_dhcp_event("dhcp.release", req
->chaddr
, req
->hlen
,
741 &req
->ciaddr
, hostname
, iface
->ifname
);
743 if (reqmsg
== DHCPV4_MSG_DECLINE
|| reqmsg
== DHCPV4_MSG_RELEASE
)
746 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_MESSAGE
, 1, &msg
);
747 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_SERVERID
, 4, &serverid
);
752 reply
.yiaddr
.s_addr
= a
->addr
;
754 val
= htonl(leasetime
);
755 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_LEASETIME
, 4, &val
);
757 if (leasetime
!= UINT32_MAX
) {
758 val
= htonl(500 * leasetime
/ 1000);
759 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_RENEW
, 4, &val
);
761 val
= htonl(875 * leasetime
/ 1000);
762 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_REBIND
, 4, &val
);
765 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_NETMASK
, 4,
766 &iface
->dhcpv4_mask
.s_addr
);
769 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_HOSTNAME
,
770 strlen(a
->hostname
), a
->hostname
);
772 if (iface
->dhcpv4_bcast
.s_addr
!= INADDR_ANY
)
773 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_BROADCAST
, 4, &iface
->dhcpv4_bcast
);
776 if (reqmsg
== DHCPV4_MSG_REQUEST
) {
777 struct dhcpv4_auth_forcerenew auth
= {
781 .replay
= {htonl(time(NULL
)), htonl(++serial
)},
786 memcpy(auth
.key
, a
->key
, sizeof(auth
.key
));
787 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_AUTHENTICATION
, sizeof(auth
), &auth
);
790 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE
,
798 memset(&ifr
, 0, sizeof(ifr
));
799 strncpy(ifr
.ifr_name
, iface
->ifname
, sizeof(ifr
.ifr_name
) - 1);
801 if (!ioctl(sock
, SIOCGIFMTU
, &ifr
)) {
802 uint16_t mtu
= htons(ifr
.ifr_mtu
);
803 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_MTU
, 2, &mtu
);
806 if (iface
->search
&& iface
->search_len
<= 255)
807 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_SEARCH_DOMAIN
,
808 iface
->search_len
, iface
->search
);
809 else if (!res_init() && _res
.dnsrch
[0] && _res
.dnsrch
[0][0]) {
810 uint8_t search_buf
[256];
811 int len
= dn_comp(_res
.dnsrch
[0], search_buf
,
812 sizeof(search_buf
), NULL
, NULL
);
814 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_SEARCH_DOMAIN
,
818 if (iface
->dhcpv4_router_cnt
== 0)
819 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_ROUTER
, 4, &iface
->dhcpv4_local
);
821 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_ROUTER
,
822 4 * iface
->dhcpv4_router_cnt
, iface
->dhcpv4_router
);
825 if (iface
->dhcpv4_dns_cnt
== 0)
826 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_DNSSERVER
, 4, &iface
->dhcpv4_local
);
828 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_DNSSERVER
,
829 4 * iface
->dhcpv4_dns_cnt
, iface
->dhcpv4_dns
);
832 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_END
, 0, NULL
);
834 struct sockaddr_in dest
= *((struct sockaddr_in
*)addr
);
835 if (req
->giaddr
.s_addr
) {
837 * relay agent is configured, send reply to the agent
839 dest
.sin_addr
= req
->giaddr
;
840 dest
.sin_port
= htons(DHCPV4_SERVER_PORT
);
841 } else if (req
->ciaddr
.s_addr
&& req
->ciaddr
.s_addr
!= dest
.sin_addr
.s_addr
) {
843 * client has existing configuration (ciaddr is set) AND this address is
844 * not the address it used for the dhcp message
846 dest
.sin_addr
= req
->ciaddr
;
847 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
848 } else if ((ntohs(req
->flags
) & DHCPV4_FLAG_BROADCAST
) ||
849 req
->hlen
!= reply
.hlen
|| !reply
.yiaddr
.s_addr
) {
851 * client requests a broadcast reply OR we can't offer an IP
853 dest
.sin_addr
.s_addr
= INADDR_BROADCAST
;
854 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
855 } else if (!req
->ciaddr
.s_addr
&& msg
== DHCPV4_MSG_NAK
) {
857 * client has no previous configuration -> no IP, so we need to reply
858 * with a broadcast packet
860 dest
.sin_addr
.s_addr
= INADDR_BROADCAST
;
861 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
863 struct arpreq arp
= {.arp_flags
= ATF_COM
};
866 * send reply to the newly (in this proccess) allocated IP
868 dest
.sin_addr
= reply
.yiaddr
;
869 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
871 memcpy(arp
.arp_ha
.sa_data
, req
->chaddr
, 6);
872 memcpy(&arp
.arp_pa
, &dest
, sizeof(arp
.arp_pa
));
873 memcpy(arp
.arp_dev
, iface
->ifname
, sizeof(arp
.arp_dev
));
875 if (ioctl(sock
, SIOCSARP
, &arp
) < 0)
876 syslog(LOG_ERR
, "ioctl(SIOCSARP): %m");
879 if (sendto(sock
, &reply
, PACKET_SIZE(&reply
, cookie
), MSG_DONTWAIT
,
880 (struct sockaddr
*)&dest
, sizeof(dest
)) < 0)
881 syslog(LOG_ERR
, "Failed to send %s to %s - %s: %m",
882 dhcpv4_msg_to_string(msg
),
883 dest
.sin_addr
.s_addr
== INADDR_BROADCAST
?
884 "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req
->chaddr
, req
->hlen
),
885 inet_ntoa(dest
.sin_addr
));
887 syslog(LOG_NOTICE
, "Sent %s to %s - %s",
888 dhcpv4_msg_to_string(msg
),
889 dest
.sin_addr
.s_addr
== INADDR_BROADCAST
?
890 "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req
->chaddr
, req
->hlen
),
891 inet_ntoa(dest
.sin_addr
));
895 if (msg
== DHCPV4_MSG_ACK
)
896 ubus_bcast_dhcp_event("dhcp.ack", req
->chaddr
, req
->hlen
, &reply
.yiaddr
,
897 hostname
, iface
->ifname
);
901 static bool dhcpv4_insert_assignment(struct list_head
*list
, struct dhcp_assignment
*a
,
904 uint32_t h_addr
= ntohl(addr
);
905 struct dhcp_assignment
*c
;
907 list_for_each_entry(c
, list
, head
) {
908 uint32_t c_addr
= ntohl(c
->addr
);
910 if (c_addr
== h_addr
)
917 /* Insert new node before c (might match list head) */
919 list_add_tail(&a
->head
, &c
->head
);
924 static char* ip4toa(uint32_t addr
)
928 snprintf(buf
, sizeof(buf
), "%u.%u.%u.%u",
929 ((uint8_t *)&addr
)[0], ((uint8_t *)&addr
)[1],
930 ((uint8_t *)&addr
)[2], ((uint8_t *)&addr
)[3]);
935 static bool dhcpv4_assign(struct interface
*iface
, struct dhcp_assignment
*a
,
938 uint32_t start
= ntohl(iface
->dhcpv4_start_ip
.s_addr
);
939 uint32_t end
= ntohl(iface
->dhcpv4_end_ip
.s_addr
);
940 uint32_t count
= end
- start
+ 1;
944 /* Preconfigured IP address by static lease */
946 assigned
= dhcpv4_insert_assignment(&iface
->dhcpv4_assignments
,
950 syslog(LOG_INFO
, "Assigning static IP: %s", ip4toa(a
->addr
));
955 /* try to assign the IP the client asked for */
956 if (start
<= ntohl(raddr
) && ntohl(raddr
) <= end
&&
957 !config_find_lease_by_ipaddr(raddr
)) {
958 assigned
= dhcpv4_insert_assignment(&iface
->dhcpv4_assignments
,
962 syslog(LOG_INFO
, "Assigning the IP the client asked for: %s",
969 /* Seed RNG with checksum of hwaddress */
970 for (size_t i
= 0; i
< sizeof(a
->hwaddr
); ++i
) {
971 /* Knuth's multiplicative method */
972 uint8_t o
= a
->hwaddr
[i
];
973 seed
+= (o
*2654435761) % UINT32_MAX
;
978 for (uint32_t i
= 0, try = (((uint32_t)rand()) % count
) + start
; i
< count
;
979 ++i
, try = (((try - start
) + 1) % count
) + start
) {
980 uint32_t n_try
= htonl(try);
982 if (config_find_lease_by_ipaddr(n_try
))
985 assigned
= dhcpv4_insert_assignment(&iface
->dhcpv4_assignments
,
989 syslog(LOG_INFO
, "Assigning mapped IP: %s (try %u of %u)",
990 ip4toa(a
->addr
), i
+ 1, count
);
996 syslog(LOG_WARNING
, "Can't assign any IP address -> address space is full");
1001 static struct dhcp_assignment
*
1002 dhcpv4_lease(struct interface
*iface
, enum dhcpv4_msg msg
, const uint8_t *mac
,
1003 const uint32_t reqaddr
, uint32_t *leasetime
, const char *hostname
,
1004 const size_t hostname_len
, const bool accept_fr_nonce
, bool *incl_fr_opt
,
1005 uint32_t *fr_serverid
, const char* reqopts
, const size_t reqopts_len
)
1007 struct dhcp_assignment
*a
= find_assignment_by_hwaddr(iface
, mac
);
1008 struct lease
*l
= config_find_lease_by_mac(mac
);
1009 time_t now
= odhcpd_time();
1011 if (l
&& a
&& a
->lease
!= l
) {
1016 if (a
&& (a
->flags
& OAF_BOUND
) && a
->fr_ip
) {
1017 *fr_serverid
= a
->fr_ip
->addr
.addr
.in
.s_addr
;
1021 if (msg
== DHCPV4_MSG_DISCOVER
|| msg
== DHCPV4_MSG_REQUEST
) {
1022 bool assigned
= !!a
;
1025 if (!iface
->no_dynamic_dhcp
|| l
) {
1026 /* Create new binding */
1027 a
= alloc_assignment(0);
1029 syslog(LOG_ERR
, "Failed to alloc assignment on interface %s",
1033 memcpy(a
->hwaddr
, mac
, sizeof(a
->hwaddr
));
1034 /* Set valid time to 0 for static lease indicating */
1035 /* infinite lifetime otherwise current time */
1036 a
->valid_until
= l
? 0 : now
;
1037 a
->dhcp_free_cb
= dhcpv4_free_assignment
;
1039 a
->flags
= OAF_DHCPV4
;
1040 a
->addr
= l
? l
->ipaddr
: INADDR_ANY
;
1042 assigned
= dhcpv4_assign(iface
, a
, reqaddr
);
1045 a
->flags
|= OAF_STATIC
;
1048 a
->hostname
= strdup(l
->hostname
);
1051 a
->leasetime
= l
->leasetime
;
1053 list_add(&a
->lease_list
, &l
->assignments
);
1057 } else if (((a
->addr
& iface
->dhcpv4_mask
.s_addr
) !=
1058 (iface
->dhcpv4_start_ip
.s_addr
& iface
->dhcpv4_mask
.s_addr
)) &&
1059 !(a
->flags
& OAF_STATIC
)) {
1060 list_del_init(&a
->head
);
1061 a
->addr
= INADDR_ANY
;
1063 assigned
= dhcpv4_assign(iface
, a
, reqaddr
);
1067 uint32_t my_leasetime
;
1070 my_leasetime
= a
->leasetime
;
1072 my_leasetime
= iface
->dhcpv4_leasetime
;
1074 if ((*leasetime
== 0) || (my_leasetime
< *leasetime
))
1075 *leasetime
= my_leasetime
;
1077 if (msg
== DHCPV4_MSG_DISCOVER
) {
1078 a
->flags
&= ~OAF_BOUND
;
1080 *incl_fr_opt
= accept_fr_nonce
;
1081 if (!(a
->flags
& OAF_STATIC
))
1082 a
->valid_until
= now
;
1084 if ((!(a
->flags
& OAF_STATIC
) || !a
->hostname
) && hostname_len
> 0) {
1085 a
->hostname
= realloc(a
->hostname
, hostname_len
+ 1);
1087 memcpy(a
->hostname
, hostname
, hostname_len
);
1088 a
->hostname
[hostname_len
] = 0;
1090 if (odhcpd_valid_hostname(a
->hostname
))
1091 a
->flags
&= ~OAF_BROKEN_HOSTNAME
;
1093 a
->flags
|= OAF_BROKEN_HOSTNAME
;
1097 if (reqopts_len
> 0) {
1098 a
->reqopts
= realloc(a
->reqopts
, reqopts_len
+ 1);
1100 memcpy(a
->reqopts
, reqopts
, reqopts_len
);
1101 a
->reqopts
[reqopts_len
] = 0;
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 */
1122 } else if (msg
== DHCPV4_MSG_RELEASE
&& a
) {
1123 a
->flags
&= ~OAF_BOUND
;
1125 if (!(a
->flags
& OAF_STATIC
))
1126 a
->valid_until
= now
- 1;
1128 } else if (msg
== DHCPV4_MSG_DECLINE
&& a
) {
1129 a
->flags
&= ~OAF_BOUND
;
1131 if (!(a
->flags
& OAF_STATIC
)) {
1132 memset(a
->hwaddr
, 0, sizeof(a
->hwaddr
));
1133 a
->valid_until
= now
+ 3600; /* Block address for 1h */
1137 dhcpv6_ia_write_statefile();