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 if (!iface
->dhcpv4_assignments
.next
)
92 INIT_LIST_HEAD(&iface
->dhcpv4_assignments
);
94 if (!iface
->dhcpv4_fr_ips
.next
)
95 INIT_LIST_HEAD(&iface
->dhcpv4_fr_ips
);
97 iface
->dhcpv4_event
.uloop
.fd
= socket(AF_INET
, SOCK_DGRAM
| SOCK_CLOEXEC
, IPPROTO_UDP
);
98 if (iface
->dhcpv4_event
.uloop
.fd
< 0) {
99 syslog(LOG_ERR
, "socket(AF_INET): %m");
104 /* Basic IPv4 configuration */
105 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, SOL_SOCKET
, SO_REUSEADDR
,
106 &val
, sizeof(val
)) < 0) {
107 syslog(LOG_ERR
, "setsockopt(SO_REUSEADDR): %m");
112 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, SOL_SOCKET
, SO_BROADCAST
,
113 &val
, sizeof(val
)) < 0) {
114 syslog(LOG_ERR
, "setsockopt(SO_BROADCAST): %m");
119 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, IPPROTO_IP
, IP_PKTINFO
,
120 &val
, sizeof(val
)) < 0) {
121 syslog(LOG_ERR
, "setsockopt(IP_PKTINFO): %m");
126 val
= IPTOS_PREC_INTERNETCONTROL
;
127 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, IPPROTO_IP
, IP_TOS
,
128 &val
, sizeof(val
)) < 0) {
129 syslog(LOG_ERR
, "setsockopt(IP_TOS): %m");
134 val
= IP_PMTUDISC_DONT
;
135 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, IPPROTO_IP
, IP_MTU_DISCOVER
,
136 &val
, sizeof(val
)) < 0) {
137 syslog(LOG_ERR
, "setsockopt(IP_MTU_DISCOVER): %m");
142 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, SOL_SOCKET
, SO_BINDTODEVICE
,
143 iface
->ifname
, strlen(iface
->ifname
)) < 0) {
144 syslog(LOG_ERR
, "setsockopt(SO_BINDTODEVICE): %m");
149 if (bind(iface
->dhcpv4_event
.uloop
.fd
, (struct sockaddr
*)&bind_addr
,
150 sizeof(bind_addr
)) < 0) {
151 syslog(LOG_ERR
, "bind(): %m");
156 if (setup_dhcpv4_addresses(iface
) < 0) {
161 iface
->dhcpv4_event
.handle_dgram
= handle_dhcpv4
;
162 odhcpd_register(&iface
->dhcpv4_event
);
163 } else if (iface
->dhcpv4_assignments
.next
) {
164 while (!list_empty(&iface
->dhcpv4_assignments
))
165 free_assignment(list_first_entry(&iface
->dhcpv4_assignments
,
166 struct dhcp_assignment
, head
));
170 if (ret
< 0 && iface
->dhcpv4_event
.uloop
.fd
>= 0) {
171 close(iface
->dhcpv4_event
.uloop
.fd
);
172 iface
->dhcpv4_event
.uloop
.fd
= -1;
179 static void dhcpv4_netevent_cb(unsigned long event
, struct netevent_handler_info
*info
)
181 struct interface
*iface
= info
->iface
;
183 if (!iface
|| iface
->dhcpv4
== MODE_DISABLED
)
187 case NETEV_IFINDEX_CHANGE
:
188 dhcpv4_setup_interface(iface
, true);
190 case NETEV_ADDRLIST_CHANGE
:
191 handle_addrlist_change(iface
);
198 static struct dhcp_assignment
*find_assignment_by_hwaddr(struct interface
*iface
, const uint8_t *hwaddr
)
200 struct dhcp_assignment
*a
;
202 list_for_each_entry(a
, &iface
->dhcpv4_assignments
, head
)
203 if (!memcmp(a
->hwaddr
, hwaddr
, 6))
209 static int setup_dhcpv4_addresses(struct interface
*iface
)
211 iface
->dhcpv4_start_ip
.s_addr
= INADDR_ANY
;
212 iface
->dhcpv4_end_ip
.s_addr
= INADDR_ANY
;
213 iface
->dhcpv4_local
.s_addr
= INADDR_ANY
;
214 iface
->dhcpv4_bcast
.s_addr
= INADDR_ANY
;
215 iface
->dhcpv4_mask
.s_addr
= INADDR_ANY
;
218 if (iface
->dhcpv4_start
.s_addr
& htonl(0xffff0000) ||
219 iface
->dhcpv4_end
.s_addr
& htonl(0xffff0000) ||
220 ntohl(iface
->dhcpv4_start
.s_addr
) > ntohl(iface
->dhcpv4_end
.s_addr
)) {
221 syslog(LOG_ERR
, "Invalid DHCP range for %s", iface
->name
);
225 if (!iface
->addr4_len
) {
226 syslog(LOG_ERR
, "No network(s) available on %s", iface
->name
);
230 uint32_t start
= ntohl(iface
->dhcpv4_start
.s_addr
);
231 uint32_t end
= ntohl(iface
->dhcpv4_end
.s_addr
);
233 for (size_t i
= 0; i
< iface
->addr4_len
&& start
&& end
; i
++) {
234 struct in_addr
*addr
= &iface
->addr4
[i
].addr
.in
;
237 if (addr_is_fr_ip(iface
, addr
))
240 odhcpd_bitlen2netmask(false, iface
->addr4
[i
].prefix
, &mask
);
241 if ((start
& ntohl(~mask
.s_addr
)) == start
&&
242 (end
& ntohl(~mask
.s_addr
)) == end
) {
243 iface
->dhcpv4_start_ip
.s_addr
= htonl(start
) |
244 (addr
->s_addr
& mask
.s_addr
);
245 iface
->dhcpv4_end_ip
.s_addr
= htonl(end
) |
246 (addr
->s_addr
& mask
.s_addr
);
247 iface
->dhcpv4_local
= *addr
;
248 iface
->dhcpv4_bcast
= iface
->addr4
[i
].broadcast
;
249 iface
->dhcpv4_mask
= mask
;
254 /* Don't allocate IP range for subnets bigger than 28 */
255 if (iface
->addr4
[0].prefix
> 28) {
256 syslog(LOG_ERR
, "Auto allocation of DHCP range fails on %s", iface
->name
);
260 iface
->dhcpv4_local
= iface
->addr4
[0].addr
.in
;
261 iface
->dhcpv4_bcast
= iface
->addr4
[0].broadcast
;
262 odhcpd_bitlen2netmask(false, iface
->addr4
[0].prefix
, &iface
->dhcpv4_mask
);
263 end
= start
= iface
->dhcpv4_local
.s_addr
& iface
->dhcpv4_mask
.s_addr
;
265 /* Auto allocate ranges */
266 if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffff00) { /* /24, 150 of 256, [100..249] */
267 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(100);
268 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(100 + 150 - 1);
269 } else if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffff80) { /* /25, 100 of 128, [20..119] */
270 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(20);
271 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(20 + 100 - 1);
272 } else if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffffc0) { /* /26, 50 of 64, [10..59] */
273 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(10);
274 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(10 + 50 - 1);
275 } else if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffffe0) { /* /27, 20 of 32, [10..29] */
276 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(10);
277 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(10 + 20 - 1);
278 } else { /* /28, 10 of 16, [3..12] */
279 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(3);
280 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(3 + 10 - 1);
286 static void inc_ref_cnt_ip(struct odhcpd_ref_ip
**ptr
, struct odhcpd_ref_ip
*ip
)
292 static void decr_ref_cnt_ip(struct odhcpd_ref_ip
**ptr
, struct interface
*iface
)
294 struct odhcpd_ref_ip
*ip
= *ptr
;
296 if (--ip
->ref_cnt
== 0) {
297 netlink_setup_addr(&ip
->addr
, iface
->ifindex
, false, false);
306 static bool addr_is_fr_ip(struct interface
*iface
, struct in_addr
*addr
)
308 struct odhcpd_ref_ip
*p
;
310 list_for_each_entry(p
, &iface
->dhcpv4_fr_ips
, head
) {
311 if (addr
->s_addr
== p
->addr
.addr
.in
.s_addr
)
318 static bool leases_require_fr(struct interface
*iface
, struct odhcpd_ipaddr
*addr
,
321 struct dhcp_assignment
*a
= NULL
;
322 struct odhcpd_ref_ip
*fr_ip
= NULL
;
324 list_for_each_entry(a
, &iface
->dhcpv4_assignments
, head
) {
325 if ((a
->accept_fr_nonce
|| iface
->dhcpv4_forcereconf
) &&
327 ((a
->addr
& mask
) == (addr
->addr
.in
.s_addr
& mask
))) {
329 fr_ip
= calloc(1, sizeof(*fr_ip
));
333 list_add(&fr_ip
->head
, &iface
->dhcpv4_fr_ips
);
336 inc_ref_cnt_ip(&a
->fr_ip
, fr_ip
);
340 return fr_ip
? true : false;
343 static void valid_until_cb(struct uloop_timeout
*event
)
345 struct interface
*iface
;
346 time_t now
= odhcpd_time();
348 avl_for_each_element(&interfaces
, iface
, avl
) {
349 if (iface
->dhcpv4
!= MODE_SERVER
|| iface
->dhcpv4_assignments
.next
== NULL
)
352 struct dhcp_assignment
*a
, *n
;
353 list_for_each_entry_safe(a
, n
, &iface
->dhcpv4_assignments
, head
) {
354 if (!INFINITE_VALID(a
->valid_until
) && a
->valid_until
< now
)
358 uloop_timeout_set(event
, 1000);
361 static void handle_addrlist_change(struct interface
*iface
)
363 struct odhcpd_ipaddr ip
;
364 struct odhcpd_ref_ip
*a
;
365 struct dhcp_assignment
*c
;
366 uint32_t mask
= iface
->dhcpv4_mask
.s_addr
;
368 memset(&ip
, 0, sizeof(ip
));
369 ip
.addr
.in
= iface
->dhcpv4_local
;
370 ip
.prefix
= odhcpd_netmask2bitlen(false, &iface
->dhcpv4_mask
);
371 ip
.broadcast
= iface
->dhcpv4_bcast
;
373 setup_dhcpv4_addresses(iface
);
375 if ((ip
.addr
.in
.s_addr
& mask
) ==
376 (iface
->dhcpv4_local
.s_addr
& iface
->dhcpv4_mask
.s_addr
))
379 if (ip
.addr
.in
.s_addr
&& !leases_require_fr(iface
, &ip
, mask
))
382 if (iface
->dhcpv4_local
.s_addr
== INADDR_ANY
|| list_empty(&iface
->dhcpv4_fr_ips
))
385 a
= list_first_entry(&iface
->dhcpv4_fr_ips
, struct odhcpd_ref_ip
, head
);
387 if (netlink_setup_addr(&a
->addr
, iface
->ifindex
, false, true)) {
388 syslog(LOG_ERR
, "Failed to add ip address on %s", iface
->name
);
392 list_for_each_entry(c
, &iface
->dhcpv4_assignments
, head
) {
393 if ((c
->flags
& OAF_BOUND
) && c
->fr_ip
&& !c
->fr_cnt
) {
394 if (c
->accept_fr_nonce
|| iface
->dhcpv4_forcereconf
)
395 dhcpv4_fr_rand_delay(c
);
402 static char *dhcpv4_msg_to_string(uint8_t reqmsg
)
405 case (DHCPV4_MSG_DISCOVER
):
406 return "DHCPV4_MSG_DISCOVER";
407 case (DHCPV4_MSG_OFFER
):
408 return "DHCPV4_MSG_OFFER";
409 case (DHCPV4_MSG_REQUEST
):
410 return "DHCPV4_MSG_REQUEST";
411 case (DHCPV4_MSG_DECLINE
):
412 return "DHCPV4_MSG_DECLINE";
413 case (DHCPV4_MSG_ACK
):
414 return "DHCPV4_MSG_ACK";
415 case (DHCPV4_MSG_NAK
):
416 return "DHCPV4_MSG_NAK";
417 case (DHCPV4_MSG_RELEASE
):
418 return "DHCPV4_MSG_RELEASE";
419 case (DHCPV4_MSG_INFORM
):
420 return "DHCPV4_MSG_INFORM";
421 case (DHCPV4_MSG_FORCERENEW
):
422 return "DHCPV4_MSG_FORCERENEW";
428 static void dhcpv4_free_assignment(struct dhcp_assignment
*a
)
434 static void dhcpv4_put(struct dhcpv4_message
*msg
, uint8_t **cookie
,
435 uint8_t type
, uint8_t len
, const void *data
)
437 uint8_t *c
= *cookie
;
438 uint8_t *end
= (uint8_t *)msg
+ sizeof(*msg
);
439 bool tag_only
= type
== DHCPV4_OPT_PAD
|| type
== DHCPV4_OPT_END
;
440 int total_len
= tag_only
? 1 : 2 + len
;
442 if (*cookie
+ total_len
> end
)
445 *cookie
+= total_len
;
452 memcpy(c
, data
, len
);
455 static void dhcpv4_fr_send(struct dhcp_assignment
*a
)
457 struct dhcpv4_message fr_msg
= {
458 .op
= DHCPV4_BOOTREPLY
,
464 .ciaddr
= {INADDR_ANY
},
465 .yiaddr
= {INADDR_ANY
},
466 .siaddr
= {INADDR_ANY
},
467 .giaddr
= {INADDR_ANY
},
472 struct dhcpv4_auth_forcerenew
*auth_o
, auth
= {
476 .replay
= {htonl(time(NULL
)), htonl(++serial
)},
480 struct interface
*iface
= a
->iface
;
482 odhcpd_urandom(&fr_msg
.xid
, sizeof(fr_msg
.xid
));
483 memcpy(fr_msg
.chaddr
, a
->hwaddr
, fr_msg
.hlen
);
485 fr_msg
.options
[0] = 0x63;
486 fr_msg
.options
[1] = 0x82;
487 fr_msg
.options
[2] = 0x53;
488 fr_msg
.options
[3] = 0x63;
490 uint8_t *cookie
= &fr_msg
.options
[4];
491 uint8_t msg
= DHCPV4_MSG_FORCERENEW
;
493 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_MESSAGE
, 1, &msg
);
494 if (a
->accept_fr_nonce
) {
495 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_AUTHENTICATION
, sizeof(auth
), &auth
);
496 auth_o
= (struct dhcpv4_auth_forcerenew
*)(cookie
- sizeof(auth
));
497 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_END
, 0, NULL
);
500 uint8_t secretbytes
[64];
501 memset(secretbytes
, 0, sizeof(secretbytes
));
502 memcpy(secretbytes
, a
->key
, sizeof(a
->key
));
504 for (size_t i
= 0; i
< sizeof(secretbytes
); ++i
)
505 secretbytes
[i
] ^= 0x36;
508 md5_hash(secretbytes
, sizeof(secretbytes
), &md5
);
509 md5_hash(&fr_msg
, sizeof(fr_msg
), &md5
);
510 md5_end(auth_o
->key
, &md5
);
512 for (size_t i
= 0; i
< sizeof(secretbytes
); ++i
) {
513 secretbytes
[i
] ^= 0x36;
514 secretbytes
[i
] ^= 0x5c;
518 md5_hash(secretbytes
, sizeof(secretbytes
), &md5
);
519 md5_hash(auth_o
->key
, sizeof(auth_o
->key
), &md5
);
520 md5_end(auth_o
->key
, &md5
);
522 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_SERVERID
, 4,
523 &a
->fr_ip
->addr
.addr
.in
.s_addr
);
524 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_END
, 0, NULL
);
527 struct sockaddr_in dest
;
528 memset(&dest
, 0, sizeof(dest
));
529 dest
.sin_family
= AF_INET
;
530 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
531 dest
.sin_addr
.s_addr
= a
->addr
;
533 if (sendto(iface
->dhcpv4_event
.uloop
.fd
, &fr_msg
, PACKET_SIZE(&fr_msg
, cookie
),
534 MSG_DONTWAIT
, (struct sockaddr
*)&dest
, sizeof(dest
)) < 0)
535 syslog(LOG_ERR
, "Failed to send %s to %s - %s: %m", dhcpv4_msg_to_string(msg
),
536 odhcpd_print_mac(a
->hwaddr
, sizeof(a
->hwaddr
)), inet_ntoa(dest
.sin_addr
));
538 syslog(LOG_NOTICE
, "Sent %s to %s - %s", dhcpv4_msg_to_string(msg
),
539 odhcpd_print_mac(a
->hwaddr
, sizeof(a
->hwaddr
)), inet_ntoa(dest
.sin_addr
));
542 static void dhcpv4_fr_timer(struct uloop_timeout
*event
)
544 struct dhcp_assignment
*a
= container_of(event
, struct dhcp_assignment
, fr_timer
);
546 if (a
->fr_cnt
> 0 && a
->fr_cnt
< 8) {
548 uloop_timeout_set(&a
->fr_timer
, 1000 << a
->fr_cnt
);
554 static void dhcpv4_fr_start(struct dhcp_assignment
*a
)
556 uloop_timeout_set(&a
->fr_timer
, 1000 << a
->fr_cnt
);
557 a
->fr_timer
.cb
= dhcpv4_fr_timer
;
563 static void dhcpv4_fr_delay_timer(struct uloop_timeout
*event
)
565 struct dhcp_assignment
*a
= container_of(event
, struct dhcp_assignment
, fr_timer
);
566 struct interface
*iface
= a
->iface
;
568 (iface
->dhcpv4_event
.uloop
.fd
== -1 ? dhcpv4_fr_rand_delay(a
) : dhcpv4_fr_start(a
));
571 static void dhcpv4_fr_rand_delay(struct dhcp_assignment
*a
)
573 #define MIN_DELAY 500
577 odhcpd_urandom(&msecs
, sizeof(msecs
));
579 msecs
= labs(msecs
)%MAX_FUZZ
+ MIN_DELAY
;
581 uloop_timeout_set(&a
->fr_timer
, msecs
);
582 a
->fr_timer
.cb
= dhcpv4_fr_delay_timer
;
585 static void dhcpv4_fr_stop(struct dhcp_assignment
*a
)
587 uloop_timeout_cancel(&a
->fr_timer
);
588 decr_ref_cnt_ip(&a
->fr_ip
, a
->iface
);
590 a
->fr_timer
.cb
= NULL
;
593 /* Handler for DHCPv4 messages */
594 static void handle_dhcpv4(void *addr
, void *data
, size_t len
,
595 struct interface
*iface
, _unused
void *dest_addr
)
597 struct dhcpv4_message
*req
= data
;
602 if (len
< offsetof(struct dhcpv4_message
, options
) + 4 ||
603 req
->op
!= DHCPV4_BOOTREQUEST
|| req
->hlen
!= 6)
606 syslog(LOG_NOTICE
, "Got DHCPv4 request on %s", iface
->name
);
608 if (!iface
->dhcpv4_start_ip
.s_addr
&& !iface
->dhcpv4_end_ip
.s_addr
) {
609 syslog(LOG_ERR
, "No DHCP range available on %s", iface
->name
);
613 int sock
= iface
->dhcpv4_event
.uloop
.fd
;
615 struct dhcpv4_message reply
= {
616 .op
= DHCPV4_BOOTREPLY
,
623 .ciaddr
= {INADDR_ANY
},
624 .giaddr
= req
->giaddr
,
625 .siaddr
= iface
->dhcpv4_local
,
627 memcpy(reply
.chaddr
, req
->chaddr
, sizeof(reply
.chaddr
));
629 reply
.options
[0] = 0x63;
630 reply
.options
[1] = 0x82;
631 reply
.options
[2] = 0x53;
632 reply
.options
[3] = 0x63;
634 uint8_t *cookie
= &reply
.options
[4];
635 uint8_t reqmsg
= DHCPV4_MSG_REQUEST
;
636 uint8_t msg
= DHCPV4_MSG_ACK
;
638 uint32_t reqaddr
= INADDR_ANY
;
639 uint32_t leasetime
= 0;
640 size_t hostname_len
= 0;
641 size_t reqopts_len
= 0;
644 bool accept_fr_nonce
= false;
645 bool incl_fr_opt
= false;
647 uint8_t *start
= &req
->options
[4];
648 uint8_t *end
= ((uint8_t*)data
) + len
;
649 struct dhcpv4_option
*opt
;
650 dhcpv4_for_each_option(start
, end
, opt
) {
651 if (opt
->type
== DHCPV4_OPT_MESSAGE
&& opt
->len
== 1)
652 reqmsg
= opt
->data
[0];
653 else if (opt
->type
== DHCPV4_OPT_REQOPTS
&& opt
->len
> 0) {
654 reqopts_len
= opt
->len
;
655 memcpy(reqopts
, opt
->data
, reqopts_len
);
656 reqopts
[reqopts_len
] = 0;
657 } else if (opt
->type
== DHCPV4_OPT_HOSTNAME
&& opt
->len
> 0) {
658 hostname_len
= opt
->len
;
659 memcpy(hostname
, opt
->data
, hostname_len
);
660 hostname
[hostname_len
] = 0;
661 } else if (opt
->type
== DHCPV4_OPT_IPADDRESS
&& opt
->len
== 4)
662 memcpy(&reqaddr
, opt
->data
, 4);
663 else if (opt
->type
== DHCPV4_OPT_SERVERID
&& opt
->len
== 4) {
664 if (memcmp(opt
->data
, &iface
->dhcpv4_local
, 4))
666 } else if (iface
->filter_class
&& opt
->type
== DHCPV4_OPT_USER_CLASS
) {
667 uint8_t *c
= opt
->data
, *cend
= &opt
->data
[opt
->len
];
668 for (; c
< cend
&& &c
[*c
] < cend
; c
= &c
[1 + *c
]) {
669 size_t elen
= strlen(iface
->filter_class
);
670 if (*c
== elen
&& !memcmp(&c
[1], iface
->filter_class
, elen
))
671 return; // Ignore from homenet
673 } else if (opt
->type
== DHCPV4_OPT_LEASETIME
&& opt
->len
== 4)
674 memcpy(&leasetime
, opt
->data
, 4);
675 else if (opt
->type
== DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE
&& opt
->len
> 0) {
676 for (uint8_t i
= 0; i
< opt
->len
; i
++) {
677 if (opt
->data
[i
] == 1) {
678 accept_fr_nonce
= true;
686 if (reqmsg
!= DHCPV4_MSG_DISCOVER
&& reqmsg
!= DHCPV4_MSG_REQUEST
&&
687 reqmsg
!= DHCPV4_MSG_INFORM
&& reqmsg
!= DHCPV4_MSG_DECLINE
&&
688 reqmsg
!= DHCPV4_MSG_RELEASE
)
691 struct dhcp_assignment
*a
= NULL
;
692 uint32_t serverid
= iface
->dhcpv4_local
.s_addr
;
693 uint32_t fr_serverid
= INADDR_ANY
;
695 if (reqmsg
!= DHCPV4_MSG_INFORM
)
696 a
= dhcpv4_lease(iface
, reqmsg
, req
->chaddr
, reqaddr
,
697 &leasetime
, hostname
, hostname_len
,
698 accept_fr_nonce
, &incl_fr_opt
, &fr_serverid
,
699 reqopts
, reqopts_len
);
702 if (reqmsg
== DHCPV4_MSG_REQUEST
)
703 msg
= DHCPV4_MSG_NAK
;
704 else if (reqmsg
== DHCPV4_MSG_DISCOVER
)
706 } else if (reqmsg
== DHCPV4_MSG_DISCOVER
)
707 msg
= DHCPV4_MSG_OFFER
;
708 else if (reqmsg
== DHCPV4_MSG_REQUEST
&&
709 ((reqaddr
&& reqaddr
!= a
->addr
) ||
710 (req
->ciaddr
.s_addr
&& req
->ciaddr
.s_addr
!= a
->addr
))) {
711 msg
= DHCPV4_MSG_NAK
;
713 * DHCP client requested an IP which we can't offer to him. Probably the
714 * client changed the network or the network has been changed. The reply
715 * type is set to DHCPV4_MSG_NAK, because the client should not use that IP.
717 * For modern devices we build an answer that includes a valid IP, like
718 * a DHCPV4_MSG_ACK. The client will use that IP and doesn't need to
719 * perform additional DHCP round trips.
725 * Buggy clients do serverid checking in nack messages; therefore set the
726 * serverid in nack messages triggered by a previous force renew equal to
727 * the server id in use at that time by the server
731 serverid
= fr_serverid
;
733 if (req
->ciaddr
.s_addr
&&
734 ((iface
->dhcpv4_start_ip
.s_addr
& iface
->dhcpv4_mask
.s_addr
) !=
735 (req
->ciaddr
.s_addr
& iface
->dhcpv4_mask
.s_addr
)))
736 req
->ciaddr
.s_addr
= INADDR_ANY
;
739 syslog(LOG_NOTICE
, "Received %s from %s on %s", dhcpv4_msg_to_string(reqmsg
),
740 odhcpd_print_mac(req
->chaddr
, req
->hlen
), iface
->name
);
743 if (reqmsg
== DHCPV4_MSG_RELEASE
)
744 ubus_bcast_dhcp_event("dhcp.release", req
->chaddr
, req
->hlen
,
745 &req
->ciaddr
, hostname
, iface
->ifname
);
747 if (reqmsg
== DHCPV4_MSG_DECLINE
|| reqmsg
== DHCPV4_MSG_RELEASE
)
750 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_MESSAGE
, 1, &msg
);
751 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_SERVERID
, 4, &serverid
);
756 reply
.yiaddr
.s_addr
= a
->addr
;
758 val
= htonl(leasetime
);
759 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_LEASETIME
, 4, &val
);
761 if (leasetime
!= UINT32_MAX
) {
762 val
= htonl(500 * leasetime
/ 1000);
763 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_RENEW
, 4, &val
);
765 val
= htonl(875 * leasetime
/ 1000);
766 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_REBIND
, 4, &val
);
769 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_NETMASK
, 4,
770 &iface
->dhcpv4_mask
.s_addr
);
773 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_HOSTNAME
,
774 strlen(a
->hostname
), a
->hostname
);
776 if (iface
->dhcpv4_bcast
.s_addr
!= INADDR_ANY
)
777 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_BROADCAST
, 4, &iface
->dhcpv4_bcast
);
780 if (reqmsg
== DHCPV4_MSG_REQUEST
) {
781 struct dhcpv4_auth_forcerenew auth
= {
785 .replay
= {htonl(time(NULL
)), htonl(++serial
)},
790 memcpy(auth
.key
, a
->key
, sizeof(auth
.key
));
791 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_AUTHENTICATION
, sizeof(auth
), &auth
);
794 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE
,
802 memset(&ifr
, 0, sizeof(ifr
));
803 strncpy(ifr
.ifr_name
, iface
->ifname
, sizeof(ifr
.ifr_name
) - 1);
805 if (!ioctl(sock
, SIOCGIFMTU
, &ifr
)) {
806 uint16_t mtu
= htons(ifr
.ifr_mtu
);
807 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_MTU
, 2, &mtu
);
810 if (iface
->search
&& iface
->search_len
<= 255)
811 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_SEARCH_DOMAIN
,
812 iface
->search_len
, iface
->search
);
813 else if (!res_init() && _res
.dnsrch
[0] && _res
.dnsrch
[0][0]) {
814 uint8_t search_buf
[256];
815 int len
= dn_comp(_res
.dnsrch
[0], search_buf
,
816 sizeof(search_buf
), NULL
, NULL
);
818 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_SEARCH_DOMAIN
,
822 if (iface
->dhcpv4_router_cnt
== 0)
823 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_ROUTER
, 4, &iface
->dhcpv4_local
);
825 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_ROUTER
,
826 4 * iface
->dhcpv4_router_cnt
, iface
->dhcpv4_router
);
829 if (iface
->dhcpv4_dns_cnt
== 0)
830 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_DNSSERVER
, 4, &iface
->dhcpv4_local
);
832 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_DNSSERVER
,
833 4 * iface
->dhcpv4_dns_cnt
, iface
->dhcpv4_dns
);
836 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_END
, 0, NULL
);
838 struct sockaddr_in dest
= *((struct sockaddr_in
*)addr
);
839 if (req
->giaddr
.s_addr
) {
841 * relay agent is configured, send reply to the agent
843 dest
.sin_addr
= req
->giaddr
;
844 dest
.sin_port
= htons(DHCPV4_SERVER_PORT
);
845 } else if (req
->ciaddr
.s_addr
&& req
->ciaddr
.s_addr
!= dest
.sin_addr
.s_addr
) {
847 * client has existing configuration (ciaddr is set) AND this address is
848 * not the address it used for the dhcp message
850 dest
.sin_addr
= req
->ciaddr
;
851 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
852 } else if ((ntohs(req
->flags
) & DHCPV4_FLAG_BROADCAST
) ||
853 req
->hlen
!= reply
.hlen
|| !reply
.yiaddr
.s_addr
) {
855 * client requests a broadcast reply OR we can't offer an IP
857 dest
.sin_addr
.s_addr
= INADDR_BROADCAST
;
858 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
859 } else if (!req
->ciaddr
.s_addr
&& msg
== DHCPV4_MSG_NAK
) {
861 * client has no previous configuration -> no IP, so we need to reply
862 * with a broadcast packet
864 dest
.sin_addr
.s_addr
= INADDR_BROADCAST
;
865 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
867 struct arpreq arp
= {.arp_flags
= ATF_COM
};
870 * send reply to the newly (in this proccess) allocated IP
872 dest
.sin_addr
= reply
.yiaddr
;
873 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
875 memcpy(arp
.arp_ha
.sa_data
, req
->chaddr
, 6);
876 memcpy(&arp
.arp_pa
, &dest
, sizeof(arp
.arp_pa
));
877 memcpy(arp
.arp_dev
, iface
->ifname
, sizeof(arp
.arp_dev
));
879 if (ioctl(sock
, SIOCSARP
, &arp
) < 0)
880 syslog(LOG_ERR
, "ioctl(SIOCSARP): %m");
883 if (sendto(sock
, &reply
, PACKET_SIZE(&reply
, cookie
), MSG_DONTWAIT
,
884 (struct sockaddr
*)&dest
, sizeof(dest
)) < 0)
885 syslog(LOG_ERR
, "Failed to send %s to %s - %s: %m",
886 dhcpv4_msg_to_string(msg
),
887 dest
.sin_addr
.s_addr
== INADDR_BROADCAST
?
888 "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req
->chaddr
, req
->hlen
),
889 inet_ntoa(dest
.sin_addr
));
891 syslog(LOG_NOTICE
, "Sent %s to %s - %s",
892 dhcpv4_msg_to_string(msg
),
893 dest
.sin_addr
.s_addr
== INADDR_BROADCAST
?
894 "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req
->chaddr
, req
->hlen
),
895 inet_ntoa(dest
.sin_addr
));
899 if (msg
== DHCPV4_MSG_ACK
)
900 ubus_bcast_dhcp_event("dhcp.ack", req
->chaddr
, req
->hlen
, &reply
.yiaddr
,
901 hostname
, iface
->ifname
);
905 static bool dhcpv4_assign(struct interface
*iface
, struct dhcp_assignment
*a
,
908 struct dhcp_assignment
*c
;
909 uint32_t start
= ntohl(iface
->dhcpv4_start_ip
.s_addr
);
910 uint32_t end
= ntohl(iface
->dhcpv4_end_ip
.s_addr
);
911 uint32_t count
= end
- start
+ 1;
914 /* Preconfigured IP address by static lease */
916 if (list_empty(&iface
->dhcpv4_assignments
)) {
917 list_add(&a
->head
, &iface
->dhcpv4_assignments
);
921 list_for_each_entry(c
, &iface
->dhcpv4_assignments
, head
) {
922 if (ntohl(c
->addr
) > ntohl(a
->addr
)) {
923 list_add_tail(&a
->head
, &c
->head
);
925 } else if (ntohl(a
->addr
) == ntohl(c
->addr
))
930 /* try to assign the IP the client asked for */
931 if (start
<= ntohl(raddr
) && ntohl(raddr
) <= end
&&
932 !config_find_lease_by_ipaddr(raddr
)) {
933 if (list_empty(&iface
->dhcpv4_assignments
)) {
934 list_add(&a
->head
, &iface
->dhcpv4_assignments
);
938 list_for_each_entry(c
, &iface
->dhcpv4_assignments
, head
) {
939 if (ntohl(raddr
) == ntohl(c
->addr
))
942 if (ntohl(c
->addr
) > ntohl(raddr
) || list_is_last(&c
->head
, &iface
->dhcpv4_assignments
)) {
943 list_add_tail(&a
->head
,
944 ntohl(c
->addr
) > ntohl(raddr
) ? &c
->head
: &iface
->dhcpv4_assignments
);
948 syslog(LOG_INFO
, "Assigning the IP the client asked for: %u.%u.%u.%u",
949 ((uint8_t *)&a
->addr
)[0], ((uint8_t *)&a
->addr
)[1],
950 ((uint8_t *)&a
->addr
)[2], ((uint8_t *)&a
->addr
)[3]);
957 /* Seed RNG with checksum of hwaddress */
958 for (size_t i
= 0; i
< sizeof(a
->hwaddr
); ++i
) {
959 /* Knuth's multiplicative method */
960 uint8_t o
= a
->hwaddr
[i
];
961 seed
+= (o
*2654435761) % UINT32_MAX
;
966 for (uint32_t i
= 0, try = (((uint32_t)rand()) % count
) + start
; i
< count
;
967 ++i
, try = (((try - start
) + 1) % count
) + start
) {
969 if (config_find_lease_by_ipaddr(htonl(try)))
972 if (list_empty(&iface
->dhcpv4_assignments
)) {
973 list_add(&a
->head
, &iface
->dhcpv4_assignments
);
974 a
->addr
= htonl(try);
976 syslog(LOG_INFO
, "Assigning mapped IP (empty list): %u.%u.%u.%u",
977 ((uint8_t *)&a
->addr
)[0], ((uint8_t *)&a
->addr
)[1],
978 ((uint8_t *)&a
->addr
)[2], ((uint8_t *)&a
->addr
)[3]);
983 list_for_each_entry(c
, &iface
->dhcpv4_assignments
, head
) {
984 if (try == ntohl(c
->addr
))
987 if (ntohl(c
->addr
) > try || list_is_last(&c
->head
, &iface
->dhcpv4_assignments
)) {
988 list_add_tail(&a
->head
,
989 ntohl(c
->addr
) > try ? &c
->head
: &iface
->dhcpv4_assignments
);
990 a
->addr
= htonl(try);
992 syslog(LOG_INFO
, "Assigning mapped IP: %u.%u.%u.%u (try %u of %u)",
993 ((uint8_t *)&a
->addr
)[0], ((uint8_t *)&a
->addr
)[1],
994 ((uint8_t *)&a
->addr
)[2], ((uint8_t *)&a
->addr
)[3],
1002 syslog(LOG_WARNING
, "Can't assign any IP address -> address space is full");
1007 static struct dhcp_assignment
*
1008 dhcpv4_lease(struct interface
*iface
, enum dhcpv4_msg msg
, const uint8_t *mac
,
1009 const uint32_t reqaddr
, uint32_t *leasetime
, const char *hostname
,
1010 const size_t hostname_len
, const bool accept_fr_nonce
, bool *incl_fr_opt
,
1011 uint32_t *fr_serverid
, const char* reqopts
, const size_t reqopts_len
)
1013 struct dhcp_assignment
*a
= find_assignment_by_hwaddr(iface
, mac
);
1014 struct lease
*l
= config_find_lease_by_mac(mac
);
1015 time_t now
= odhcpd_time();
1017 if (l
&& a
&& a
->lease
!= l
) {
1022 if (a
&& (a
->flags
& OAF_BOUND
) && a
->fr_ip
) {
1023 *fr_serverid
= a
->fr_ip
->addr
.addr
.in
.s_addr
;
1027 if (msg
== DHCPV4_MSG_DISCOVER
|| msg
== DHCPV4_MSG_REQUEST
) {
1028 bool assigned
= !!a
;
1031 if (!iface
->no_dynamic_dhcp
|| l
) {
1032 /* Create new binding */
1033 a
= calloc(1, sizeof(*a
));
1035 syslog(LOG_ERR
, "Failed to calloc binding on interface %s",
1039 memcpy(a
->hwaddr
, mac
, sizeof(a
->hwaddr
));
1040 /* Set valid time to 0 for static lease indicating */
1041 /* infinite lifetime otherwise current time */
1042 a
->valid_until
= l
? 0 : now
;
1043 a
->dhcp_free_cb
= dhcpv4_free_assignment
;
1045 a
->flags
= OAF_DHCPV4
;
1046 a
->addr
= l
? l
->ipaddr
: INADDR_ANY
;
1048 assigned
= dhcpv4_assign(iface
, a
, reqaddr
);
1051 a
->flags
|= OAF_STATIC
;
1054 a
->hostname
= strdup(l
->hostname
);
1057 a
->leasetime
= l
->leasetime
;
1059 list_add(&a
->lease_list
, &l
->assignments
);
1063 } else if (((a
->addr
& iface
->dhcpv4_mask
.s_addr
) !=
1064 (iface
->dhcpv4_start_ip
.s_addr
& iface
->dhcpv4_mask
.s_addr
)) &&
1065 !(a
->flags
& OAF_STATIC
)) {
1067 a
->addr
= INADDR_ANY
;
1069 assigned
= dhcpv4_assign(iface
, a
, reqaddr
);
1073 uint32_t my_leasetime
;
1076 my_leasetime
= a
->leasetime
;
1078 my_leasetime
= iface
->dhcpv4_leasetime
;
1080 if ((*leasetime
== 0) || (my_leasetime
< *leasetime
))
1081 *leasetime
= my_leasetime
;
1083 if (msg
== DHCPV4_MSG_DISCOVER
) {
1084 a
->flags
&= ~OAF_BOUND
;
1086 *incl_fr_opt
= accept_fr_nonce
;
1087 if (!(a
->flags
& OAF_STATIC
))
1088 a
->valid_until
= now
;
1090 if ((!(a
->flags
& OAF_STATIC
) || !a
->hostname
) && hostname_len
> 0) {
1091 a
->hostname
= realloc(a
->hostname
, hostname_len
+ 1);
1093 memcpy(a
->hostname
, hostname
, hostname_len
);
1094 a
->hostname
[hostname_len
] = 0;
1096 if (odhcpd_valid_hostname(a
->hostname
))
1097 a
->flags
&= ~OAF_BROKEN_HOSTNAME
;
1099 a
->flags
|= OAF_BROKEN_HOSTNAME
;
1103 if (reqopts_len
> 0) {
1104 a
->reqopts
= realloc(a
->reqopts
, reqopts_len
+ 1);
1106 memcpy(a
->reqopts
, reqopts
, reqopts_len
);
1107 a
->reqopts
[reqopts_len
] = 0;
1111 if (!(a
->flags
& OAF_BOUND
)) {
1112 a
->accept_fr_nonce
= accept_fr_nonce
;
1113 *incl_fr_opt
= accept_fr_nonce
;
1114 odhcpd_urandom(a
->key
, sizeof(a
->key
));
1115 a
->flags
|= OAF_BOUND
;
1117 *incl_fr_opt
= false;
1119 if (!(a
->flags
& OAF_STATIC
))
1120 a
->valid_until
= ((*leasetime
== UINT32_MAX
) ? 0 : (time_t)(now
+ *leasetime
));
1122 } else if (!assigned
&& a
) {
1123 /* Cleanup failed assignment */
1128 } else if (msg
== DHCPV4_MSG_RELEASE
&& a
) {
1129 a
->flags
&= ~OAF_BOUND
;
1131 if (!(a
->flags
& OAF_STATIC
))
1132 a
->valid_until
= now
- 1;
1134 } else if (msg
== DHCPV4_MSG_DECLINE
&& a
) {
1135 a
->flags
&= ~OAF_BOUND
;
1137 if (!(a
->flags
& OAF_STATIC
)) {
1138 memset(a
->hwaddr
, 0, sizeof(a
->hwaddr
));
1139 a
->valid_until
= now
+ 3600; /* Block address for 1h */
1143 dhcpv6_ia_write_statefile();