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();