2 * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
3 * Copyright (C) 2016 Hans Dedecker <dedeckeh@gmail.com>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License v2 as published by
7 * the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
26 #include <net/if_arp.h>
27 #include <netinet/ip.h>
28 #include <sys/ioctl.h>
29 #include <sys/timerfd.h>
30 #include <arpa/inet.h>
32 #include <libubox/md5.h>
38 static void dhcpv4_netevent_cb(unsigned long event
, struct netevent_handler_info
*info
);
39 static int setup_dhcpv4_addresses(struct interface
*iface
);
40 static void update_static_assignments(struct interface
*iface
);
41 static void valid_until_cb(struct uloop_timeout
*event
);
42 static void handle_addrlist_change(struct interface
*iface
);
43 static void free_dhcpv4_assignment(struct dhcpv4_assignment
*a
);
44 static void dhcpv4_fr_start(struct dhcpv4_assignment
*a
);
45 static void dhcpv4_fr_stop(struct dhcpv4_assignment
*a
);
46 static void handle_dhcpv4(void *addr
, void *data
, size_t len
,
47 struct interface
*iface
, void *dest_addr
);
48 static struct dhcpv4_assignment
* dhcpv4_lease(struct interface
*iface
,
49 enum dhcpv4_msg msg
, const uint8_t *mac
, const uint32_t reqaddr
,
50 uint32_t *leasetime
, const char *hostname
, const size_t hostname_len
,
51 const bool accept_fr_nonce
, bool *incl_fr_opt
, uint32_t *fr_serverid
);
53 static struct netevent_handler dhcpv4_netevent_handler
= { .cb
= dhcpv4_netevent_cb
, };
54 static struct uloop_timeout valid_until_timeout
= {.cb
= valid_until_cb
};
55 static uint32_t serial
= 0;
57 struct odhcpd_ref_ip
{
58 struct list_head head
;
60 struct odhcpd_ipaddr addr
;
63 /* Create socket and register events */
66 uloop_timeout_set(&valid_until_timeout
, 1000);
67 netlink_add_netevent_handler(&dhcpv4_netevent_handler
);
72 int dhcpv4_setup_interface(struct interface
*iface
, bool enable
)
76 if (iface
->dhcpv4_event
.uloop
.fd
> 0) {
77 uloop_fd_delete(&iface
->dhcpv4_event
.uloop
);
78 close(iface
->dhcpv4_event
.uloop
.fd
);
79 iface
->dhcpv4_event
.uloop
.fd
= -1;
82 if (iface
->dhcpv4
&& enable
) {
83 struct sockaddr_in bind_addr
= {AF_INET
, htons(DHCPV4_SERVER_PORT
),
87 if (!iface
->dhcpv4_assignments
.next
)
88 INIT_LIST_HEAD(&iface
->dhcpv4_assignments
);
90 if (!iface
->dhcpv4_fr_ips
.next
)
91 INIT_LIST_HEAD(&iface
->dhcpv4_fr_ips
);
93 iface
->dhcpv4_event
.uloop
.fd
= socket(AF_INET
, SOCK_DGRAM
| SOCK_CLOEXEC
, IPPROTO_UDP
);
94 if (iface
->dhcpv4_event
.uloop
.fd
< 0) {
95 syslog(LOG_ERR
, "socket(AF_INET): %m");
100 /* Basic IPv4 configuration */
101 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, SOL_SOCKET
, SO_REUSEADDR
,
102 &val
, sizeof(val
)) < 0) {
103 syslog(LOG_ERR
, "setsockopt(SO_REUSEADDR): %m");
108 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, SOL_SOCKET
, SO_BROADCAST
,
109 &val
, sizeof(val
)) < 0) {
110 syslog(LOG_ERR
, "setsockopt(SO_BROADCAST): %m");
115 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, IPPROTO_IP
, IP_PKTINFO
,
116 &val
, sizeof(val
)) < 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 update_static_assignments(iface
);
161 } else if (iface
->dhcpv4_assignments
.next
) {
162 while (!list_empty(&iface
->dhcpv4_assignments
))
163 free_dhcpv4_assignment(list_first_entry(&iface
->dhcpv4_assignments
,
164 struct dhcpv4_assignment
, head
));
168 if (ret
< 0 && iface
->dhcpv4_event
.uloop
.fd
> 0) {
169 close(iface
->dhcpv4_event
.uloop
.fd
);
170 iface
->dhcpv4_event
.uloop
.fd
= -1;
177 static void dhcpv4_netevent_cb(unsigned long event
, struct netevent_handler_info
*info
)
179 struct interface
*iface
= info
->iface
;
181 if (!iface
|| iface
->dhcpv4
== MODE_DISABLED
)
185 case NETEV_IFINDEX_CHANGE
:
186 dhcpv4_setup_interface(iface
, true);
188 case NETEV_ADDRLIST_CHANGE
:
189 handle_addrlist_change(iface
);
196 static struct dhcpv4_assignment
*find_assignment_by_hwaddr(struct interface
*iface
, const uint8_t *hwaddr
)
198 struct dhcpv4_assignment
*a
;
200 list_for_each_entry(a
, &iface
->dhcpv4_assignments
, head
)
201 if (!memcmp(a
->hwaddr
, hwaddr
, 6))
207 static struct dhcpv4_assignment
*find_assignment_by_addr(struct interface
*iface
, const uint32_t addr
)
209 struct dhcpv4_assignment
*a
;
211 list_for_each_entry(a
, &iface
->dhcpv4_assignments
, head
)
218 static int setup_dhcpv4_addresses(struct interface
*iface
)
220 iface
->dhcpv4_start_ip
.s_addr
= INADDR_ANY
;
221 iface
->dhcpv4_end_ip
.s_addr
= INADDR_ANY
;
222 iface
->dhcpv4_local
.s_addr
= INADDR_ANY
;
223 iface
->dhcpv4_bcast
.s_addr
= INADDR_ANY
;
224 iface
->dhcpv4_mask
.s_addr
= INADDR_ANY
;
227 if (iface
->dhcpv4_start
.s_addr
& htonl(0xffff0000) ||
228 iface
->dhcpv4_end
.s_addr
& htonl(0xffff0000) ||
229 ntohl(iface
->dhcpv4_start
.s_addr
) > ntohl(iface
->dhcpv4_end
.s_addr
)) {
230 syslog(LOG_ERR
, "invalid DHCP range for %s", iface
->name
);
234 if (!iface
->addr4_len
) {
235 syslog(LOG_WARNING
, "no network(s) available on %s", iface
->name
);
239 uint32_t start
= ntohl(iface
->dhcpv4_start
.s_addr
);
240 uint32_t end
= ntohl(iface
->dhcpv4_end
.s_addr
);
242 for (size_t i
= 0; i
< iface
->addr4_len
&& start
&& end
; i
++) {
243 struct in_addr
*addr
= &iface
->addr4
[i
].addr
.in
;
246 odhcpd_bitlen2netmask(false, iface
->addr4
[i
].prefix
, &mask
);
247 if ((start
& ntohl(~mask
.s_addr
)) == start
&&
248 (end
& ntohl(~mask
.s_addr
)) == end
) {
249 iface
->dhcpv4_start_ip
.s_addr
= htonl(start
) |
250 (addr
->s_addr
& mask
.s_addr
);
251 iface
->dhcpv4_end_ip
.s_addr
= htonl(end
) |
252 (addr
->s_addr
& mask
.s_addr
);
253 iface
->dhcpv4_local
= *addr
;
254 iface
->dhcpv4_bcast
= iface
->addr4
[i
].broadcast
;
255 iface
->dhcpv4_mask
= mask
;
260 /* Don't allocate IP range for subnets bigger than 28 */
261 if (iface
->addr4
[0].prefix
> 28) {
262 syslog(LOG_WARNING
, "auto allocation of DHCP range fails on %s", iface
->name
);
266 iface
->dhcpv4_local
= iface
->addr4
[0].addr
.in
;
267 iface
->dhcpv4_bcast
= iface
->addr4
[0].broadcast
;
268 odhcpd_bitlen2netmask(false, iface
->addr4
[0].prefix
, &iface
->dhcpv4_mask
);
269 end
= start
= iface
->dhcpv4_local
.s_addr
& iface
->dhcpv4_mask
.s_addr
;
271 /* Auto allocate ranges */
272 if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffff00) {
273 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(100);
274 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(250);
275 } else if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffffc0) {
276 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(10);
277 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(60);
278 } else if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffffe0) {
279 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(10);
280 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(30);
282 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(3);
283 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(12);
289 static void update_static_assignments(struct interface
*iface
)
291 struct dhcpv4_assignment
*a
, *c
;
293 /* Cleanup static entries not belonging to the network */
294 list_for_each_entry_safe(a
, c
, &iface
->dhcpv4_assignments
, head
) {
295 if ((a
->flags
& OAF_STATIC
) &&
296 ((a
->addr
& iface
->dhcpv4_mask
.s_addr
) !=
297 (iface
->dhcpv4_start
.s_addr
& iface
->dhcpv4_mask
.s_addr
)))
298 free_dhcpv4_assignment(a
);
301 /* Parse static entries */
303 list_for_each_entry(lease
, &leases
, head
) {
304 if ((iface
->dhcpv4_start_ip
.s_addr
& iface
->dhcpv4_mask
.s_addr
) !=
305 (lease
->ipaddr
.s_addr
& iface
->dhcpv4_mask
.s_addr
)) {
309 a
= find_assignment_by_hwaddr(iface
, lease
->mac
.ether_addr_octet
);
312 /* Check if there's an assignment with the specified IP address */
313 if (find_assignment_by_addr(iface
, lease
->ipaddr
.s_addr
))
316 /* Construct entry */
317 a
= calloc(1, sizeof(*a
));
319 syslog(LOG_ERR
, "Calloc failed for static lease on interface %s",
323 memcpy(a
->hwaddr
, lease
->mac
.ether_addr_octet
, sizeof(a
->hwaddr
));
326 a
->leasetime
= lease
->dhcpv4_leasetime
;
328 a
->addr
= lease
->ipaddr
.s_addr
;
329 /* Static assignment */
330 a
->flags
|= OAF_STATIC
;
334 if (lease
->hostname
[0]) {
336 a
->hostname
= strdup(lease
->hostname
);
339 /* Assign to all interfaces */
340 list_for_each_entry(c
, &iface
->dhcpv4_assignments
, head
) {
341 if (ntohl(c
->addr
) > ntohl(a
->addr
)) {
342 list_add_tail(&a
->head
, &c
->head
);
347 if (&c
->head
== &iface
->dhcpv4_assignments
)
348 list_add(&a
->head
, &iface
->dhcpv4_assignments
);
352 static void inc_ref_cnt_ip(struct odhcpd_ref_ip
**ptr
, struct odhcpd_ref_ip
*ip
)
358 static void decr_ref_cnt_ip(struct odhcpd_ref_ip
**ptr
, struct interface
*iface
)
360 struct odhcpd_ref_ip
*ip
= *ptr
;
362 if (--ip
->ref_cnt
== 0) {
363 netlink_setup_addr(&ip
->addr
, iface
->ifindex
, false, false);
372 static bool leases_require_fr(struct interface
*iface
, struct odhcpd_ipaddr
*addr
,
375 struct dhcpv4_assignment
*a
= NULL
;
376 struct odhcpd_ref_ip
*fr_ip
= NULL
;
378 list_for_each_entry(a
, &iface
->dhcpv4_assignments
, head
) {
379 if ((a
->accept_fr_nonce
|| iface
->dhcpv4_forcereconf
) &&
381 ((a
->addr
& mask
) == (addr
->addr
.in
.s_addr
& mask
))) {
383 fr_ip
= calloc(1, sizeof(*fr_ip
));
387 list_add(&fr_ip
->head
, &iface
->dhcpv4_fr_ips
);
390 inc_ref_cnt_ip(&a
->fr_ip
, fr_ip
);
394 return fr_ip
? true : false;
397 static void valid_until_cb(struct uloop_timeout
*event
)
399 time_t now
= odhcpd_time();
400 struct interface
*iface
;
401 list_for_each_entry(iface
, &interfaces
, head
) {
402 if (iface
->dhcpv4
!= MODE_SERVER
|| iface
->dhcpv4_assignments
.next
== NULL
)
405 struct dhcpv4_assignment
*a
, *n
;
406 list_for_each_entry_safe(a
, n
, &iface
->dhcpv4_assignments
, head
) {
407 if (!INFINITE_VALID(a
->valid_until
) && a
->valid_until
< now
)
408 free_dhcpv4_assignment(a
);
411 uloop_timeout_set(event
, 1000);
414 static void handle_addrlist_change(struct interface
*iface
)
416 struct odhcpd_ipaddr ip
;
417 struct odhcpd_ref_ip
*a
;
418 struct dhcpv4_assignment
*c
;
419 uint32_t mask
= iface
->dhcpv4_mask
.s_addr
;
421 memset(&ip
, 0, sizeof(ip
));
422 ip
.addr
.in
= iface
->dhcpv4_local
;
423 ip
.prefix
= odhcpd_netmask2bitlen(false, &iface
->dhcpv4_mask
);
424 ip
.broadcast
= iface
->dhcpv4_bcast
;
426 setup_dhcpv4_addresses(iface
);
428 if ((ip
.addr
.in
.s_addr
& mask
) ==
429 (iface
->dhcpv4_local
.s_addr
& iface
->dhcpv4_mask
.s_addr
))
432 if (ip
.addr
.in
.s_addr
&& !leases_require_fr(iface
, &ip
, mask
))
435 if (iface
->dhcpv4_local
.s_addr
== INADDR_ANY
|| list_empty(&iface
->dhcpv4_fr_ips
))
438 a
= list_first_entry(&iface
->dhcpv4_fr_ips
, struct odhcpd_ref_ip
, head
);
440 if (netlink_setup_addr(&a
->addr
, iface
->ifindex
, false, true)) {
441 syslog(LOG_ERR
, "Failed to add ip address");
445 list_for_each_entry(c
, &iface
->dhcpv4_assignments
, head
) {
446 if ((c
->flags
& OAF_BOUND
) && c
->fr_ip
&& !c
->fr_cnt
) {
447 if (c
->accept_fr_nonce
|| iface
->dhcpv4_forcereconf
)
455 static char *dhcpv4_msg_to_string(uint8_t reqmsg
)
458 case (DHCPV4_MSG_DISCOVER
):
459 return "DHCPV4_MSG_DISCOVER";
460 case (DHCPV4_MSG_OFFER
):
461 return "DHCPV4_MSG_OFFER";
462 case (DHCPV4_MSG_REQUEST
):
463 return "DHCPV4_MSG_REQUEST";
464 case (DHCPV4_MSG_DECLINE
):
465 return "DHCPV4_MSG_DECLINE";
466 case (DHCPV4_MSG_ACK
):
467 return "DHCPV4_MSG_ACK";
468 case (DHCPV4_MSG_NAK
):
469 return "DHCPV4_MSG_NAK";
470 case (DHCPV4_MSG_RELEASE
):
471 return "DHCPV4_MSG_RELEASE";
472 case (DHCPV4_MSG_INFORM
):
473 return "DHCPV4_MSG_INFORM";
474 case (DHCPV4_MSG_FORCERENEW
):
475 return "DHCPV4_MSG_FORCERENEW";
481 static void free_dhcpv4_assignment(struct dhcpv4_assignment
*a
)
493 static void dhcpv4_put(struct dhcpv4_message
*msg
, uint8_t **cookie
,
494 uint8_t type
, uint8_t len
, const void *data
)
496 uint8_t *c
= *cookie
;
497 uint8_t *end
= (uint8_t *)msg
+ sizeof(*msg
);
499 if (*cookie
+ 2 + len
> end
)
504 memcpy(c
, data
, len
);
509 static void dhcpv4_fr_send(struct dhcpv4_assignment
*a
)
511 struct dhcpv4_message fr_msg
= {
512 .op
= DHCPV4_BOOTREPLY
,
518 .ciaddr
= {INADDR_ANY
},
519 .yiaddr
= {INADDR_ANY
},
520 .siaddr
= {INADDR_ANY
},
521 .giaddr
= {INADDR_ANY
},
526 struct dhcpv4_auth_forcerenew
*auth_o
, auth
= {
530 .replay
= {htonl(time(NULL
)), htonl(++serial
)},
534 struct interface
*iface
= a
->iface
;
536 odhcpd_urandom(&fr_msg
.xid
, sizeof(fr_msg
.xid
));
537 memcpy(fr_msg
.chaddr
, a
->hwaddr
, fr_msg
.hlen
);
539 fr_msg
.options
[0] = 0x63;
540 fr_msg
.options
[1] = 0x82;
541 fr_msg
.options
[2] = 0x53;
542 fr_msg
.options
[3] = 0x63;
544 uint8_t *cookie
= &fr_msg
.options
[4];
545 uint8_t msg
= DHCPV4_MSG_FORCERENEW
;
547 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_MESSAGE
, 1, &msg
);
548 if (a
->accept_fr_nonce
) {
549 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_AUTHENTICATION
, sizeof(auth
), &auth
);
550 auth_o
= (struct dhcpv4_auth_forcerenew
*)(cookie
- sizeof(auth
));
551 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_END
, 0, NULL
);
554 uint8_t secretbytes
[64];
555 memset(secretbytes
, 0, sizeof(secretbytes
));
556 memcpy(secretbytes
, a
->key
, sizeof(a
->key
));
558 for (size_t i
= 0; i
< sizeof(secretbytes
); ++i
)
559 secretbytes
[i
] ^= 0x36;
562 md5_hash(secretbytes
, sizeof(secretbytes
), &md5
);
563 md5_hash(&fr_msg
, sizeof(fr_msg
), &md5
);
564 md5_end(auth_o
->key
, &md5
);
566 for (size_t i
= 0; i
< sizeof(secretbytes
); ++i
) {
567 secretbytes
[i
] ^= 0x36;
568 secretbytes
[i
] ^= 0x5c;
572 md5_hash(secretbytes
, sizeof(secretbytes
), &md5
);
573 md5_hash(auth_o
->key
, sizeof(auth_o
->key
), &md5
);
574 md5_end(auth_o
->key
, &md5
);
576 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_SERVERID
, 4,
577 &a
->fr_ip
->addr
.addr
.in
.s_addr
);
578 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_END
, 0, NULL
);
581 struct sockaddr_in dest
;
582 memset(&dest
, 0, sizeof(dest
));
583 dest
.sin_family
= AF_INET
;
584 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
585 dest
.sin_addr
.s_addr
= a
->addr
;
587 syslog(LOG_WARNING
, "sending %s to %02x:%02x:%02x:%02x:%02x:%02x - %s",
588 dhcpv4_msg_to_string(msg
),
589 a
->hwaddr
[0], a
->hwaddr
[1], a
->hwaddr
[2],
590 a
->hwaddr
[3], a
->hwaddr
[4], a
->hwaddr
[5],
591 inet_ntoa(dest
.sin_addr
));
593 sendto(iface
->dhcpv4_event
.uloop
.fd
, &fr_msg
, sizeof(fr_msg
),
594 MSG_DONTWAIT
, (struct sockaddr
*)&dest
, sizeof(dest
));
597 static void dhcpv4_fr_timer(struct uloop_timeout
*event
)
599 struct dhcpv4_assignment
*a
= container_of(event
, struct dhcpv4_assignment
, fr_timer
);
601 if (a
->fr_cnt
> 0 && a
->fr_cnt
< 8) {
603 uloop_timeout_set(&a
->fr_timer
, 1000 << a
->fr_cnt
);
609 static void dhcpv4_fr_start(struct dhcpv4_assignment
*a
)
611 uloop_timeout_set(&a
->fr_timer
, 1000 << a
->fr_cnt
);
612 a
->fr_timer
.cb
= dhcpv4_fr_timer
;
618 static void dhcpv4_fr_stop(struct dhcpv4_assignment
*a
)
620 uloop_timeout_cancel(&a
->fr_timer
);
621 decr_ref_cnt_ip(&a
->fr_ip
, a
->iface
);
623 a
->fr_timer
.cb
= NULL
;
626 // Handler for DHCPv4 messages
627 static void handle_dhcpv4(void *addr
, void *data
, size_t len
,
628 struct interface
*iface
, _unused
void *dest_addr
)
633 struct dhcpv4_message
*req
= data
;
634 if (len
< offsetof(struct dhcpv4_message
, options
) + 4 ||
635 req
->op
!= DHCPV4_BOOTREQUEST
|| req
->hlen
!= 6)
639 syslog(LOG_NOTICE
, "Got DHCPv4 request");
641 if (!iface
->dhcpv4_start_ip
.s_addr
&& !iface
->dhcpv4_end_ip
.s_addr
) {
642 syslog(LOG_WARNING
, "No DHCP range available on %s", iface
->name
);
646 int sock
= iface
->dhcpv4_event
.uloop
.fd
;
648 struct dhcpv4_message reply
= {
649 .op
= DHCPV4_BOOTREPLY
,
656 .ciaddr
= {INADDR_ANY
},
657 .giaddr
= req
->giaddr
,
658 .siaddr
= iface
->dhcpv4_local
,
660 memcpy(reply
.chaddr
, req
->chaddr
, sizeof(reply
.chaddr
));
662 reply
.options
[0] = 0x63;
663 reply
.options
[1] = 0x82;
664 reply
.options
[2] = 0x53;
665 reply
.options
[3] = 0x63;
667 uint8_t *cookie
= &reply
.options
[4];
668 uint8_t reqmsg
= DHCPV4_MSG_REQUEST
;
669 uint8_t msg
= DHCPV4_MSG_ACK
;
671 uint32_t reqaddr
= INADDR_ANY
;
672 uint32_t leasetime
= 0;
673 size_t hostname_len
= 0;
675 bool accept_fr_nonce
= false;
676 bool incl_fr_opt
= false;
678 uint8_t *start
= &req
->options
[4];
679 uint8_t *end
= ((uint8_t*)data
) + len
;
680 struct dhcpv4_option
*opt
;
681 dhcpv4_for_each_option(start
, end
, opt
) {
682 if (opt
->type
== DHCPV4_OPT_MESSAGE
&& opt
->len
== 1)
683 reqmsg
= opt
->data
[0];
684 else if (opt
->type
== DHCPV4_OPT_HOSTNAME
&& opt
->len
> 0) {
685 hostname_len
= opt
->len
;
686 memcpy(hostname
, opt
->data
, hostname_len
);
687 hostname
[hostname_len
] = 0;
688 } else if (opt
->type
== DHCPV4_OPT_IPADDRESS
&& opt
->len
== 4)
689 memcpy(&reqaddr
, opt
->data
, 4);
690 else if (opt
->type
== DHCPV4_OPT_SERVERID
&& opt
->len
== 4) {
691 if (memcmp(opt
->data
, &iface
->dhcpv4_local
, 4))
693 } else if (iface
->filter_class
&& opt
->type
== DHCPV4_OPT_USER_CLASS
) {
694 uint8_t *c
= opt
->data
, *cend
= &opt
->data
[opt
->len
];
695 for (; c
< cend
&& &c
[*c
] < cend
; c
= &c
[1 + *c
]) {
696 size_t elen
= strlen(iface
->filter_class
);
697 if (*c
== elen
&& !memcmp(&c
[1], iface
->filter_class
, elen
))
698 return; // Ignore from homenet
700 } else if (opt
->type
== DHCPV4_OPT_LEASETIME
&& opt
->len
== 4)
701 memcpy(&leasetime
, opt
->data
, 4);
702 else if (opt
->type
== DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE
&& opt
->len
> 0) {
703 for (uint8_t i
= 0; i
< opt
->len
; i
++) {
704 if (opt
->data
[i
] == 1) {
705 accept_fr_nonce
= true;
713 if (reqmsg
!= DHCPV4_MSG_DISCOVER
&& reqmsg
!= DHCPV4_MSG_REQUEST
&&
714 reqmsg
!= DHCPV4_MSG_INFORM
&& reqmsg
!= DHCPV4_MSG_DECLINE
&&
715 reqmsg
!= DHCPV4_MSG_RELEASE
)
718 struct dhcpv4_assignment
*lease
= NULL
;
719 uint32_t serverid
= iface
->dhcpv4_local
.s_addr
;
720 uint32_t fr_serverid
= INADDR_ANY
;
722 if (reqmsg
!= DHCPV4_MSG_INFORM
)
723 lease
= dhcpv4_lease(iface
, reqmsg
, req
->chaddr
, reqaddr
,
724 &leasetime
, hostname
, hostname_len
,
725 accept_fr_nonce
, &incl_fr_opt
, &fr_serverid
);
728 if (reqmsg
== DHCPV4_MSG_REQUEST
)
729 msg
= DHCPV4_MSG_NAK
;
730 else if (reqmsg
== DHCPV4_MSG_DISCOVER
)
732 } else if (reqmsg
== DHCPV4_MSG_DISCOVER
)
733 msg
= DHCPV4_MSG_OFFER
;
734 else if (reqmsg
== DHCPV4_MSG_REQUEST
&&
735 ((reqaddr
&& reqaddr
!= lease
->addr
) ||
736 (req
->ciaddr
.s_addr
&& req
->ciaddr
.s_addr
!= lease
->addr
))) {
737 msg
= DHCPV4_MSG_NAK
;
739 * DHCP client requested an IP which we can't offer to him. Probably the
740 * client changed the network or the network has been changed. The reply
741 * type is set to DHCPV4_MSG_NAK, because the client should not use that IP.
743 * For modern devices we build an answer that includes a valid IP, like
744 * a DHCPV4_MSG_ACK. The client will use that IP and doesn't need to
745 * perform additional DHCP round trips.
751 * Buggy clients do serverid checking in nack messages; therefore set the
752 * serverid in nack messages triggered by a previous force renew equal to
753 * the server id in use at that time by the server
757 serverid
= fr_serverid
;
759 if (req
->ciaddr
.s_addr
&&
760 ((iface
->dhcpv4_start_ip
.s_addr
& iface
->dhcpv4_mask
.s_addr
) !=
761 (req
->ciaddr
.s_addr
& iface
->dhcpv4_mask
.s_addr
)))
762 req
->ciaddr
.s_addr
= INADDR_ANY
;
765 syslog(LOG_WARNING
, "received %s from %02x:%02x:%02x:%02x:%02x:%02x",
766 dhcpv4_msg_to_string(reqmsg
),
767 req
->chaddr
[0],req
->chaddr
[1],req
->chaddr
[2],
768 req
->chaddr
[3],req
->chaddr
[4],req
->chaddr
[5]);
771 if (reqmsg
== DHCPV4_MSG_RELEASE
)
772 ubus_bcast_dhcp_event("dhcp.release", req
->chaddr
, req
->hlen
,
773 &req
->ciaddr
, hostname
, iface
->ifname
);
775 if (reqmsg
== DHCPV4_MSG_DECLINE
|| reqmsg
== DHCPV4_MSG_RELEASE
)
778 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_MESSAGE
, 1, &msg
);
779 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_SERVERID
, 4, &serverid
);
784 reply
.yiaddr
.s_addr
= lease
->addr
;
786 val
= htonl(leasetime
);
787 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_LEASETIME
, 4, &val
);
789 if (leasetime
!= UINT32_MAX
) {
790 val
= htonl(500 * leasetime
/ 1000);
791 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_RENEW
, 4, &val
);
793 val
= htonl(875 * leasetime
/ 1000);
794 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_REBIND
, 4, &val
);
797 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_NETMASK
, 4,
798 &iface
->dhcpv4_mask
.s_addr
);
801 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_HOSTNAME
,
802 strlen(lease
->hostname
), lease
->hostname
);
804 if (iface
->dhcpv4_bcast
.s_addr
!= INADDR_ANY
)
805 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_BROADCAST
, 4, &iface
->dhcpv4_bcast
);
808 if (reqmsg
== DHCPV4_MSG_REQUEST
) {
809 struct dhcpv4_auth_forcerenew auth
= {
813 .replay
= {htonl(time(NULL
)), htonl(++serial
)},
818 memcpy(auth
.key
, lease
->key
, sizeof(auth
.key
));
819 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_AUTHENTICATION
, sizeof(auth
), &auth
);
822 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE
,
830 memset(&ifr
, 0, sizeof(ifr
));
831 strncpy(ifr
.ifr_name
, iface
->ifname
, sizeof(ifr
.ifr_name
) - 1);
833 if (!ioctl(sock
, SIOCGIFMTU
, &ifr
)) {
834 uint16_t mtu
= htons(ifr
.ifr_mtu
);
835 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_MTU
, 2, &mtu
);
838 if (iface
->search
&& iface
->search_len
<= 255)
839 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_SEARCH_DOMAIN
,
840 iface
->search_len
, iface
->search
);
841 else if (!res_init() && _res
.dnsrch
[0] && _res
.dnsrch
[0][0]) {
842 uint8_t search_buf
[256];
843 int len
= dn_comp(_res
.dnsrch
[0], search_buf
,
844 sizeof(search_buf
), NULL
, NULL
);
846 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_SEARCH_DOMAIN
,
850 if (iface
->dhcpv4_router_cnt
== 0)
851 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_ROUTER
, 4, &iface
->dhcpv4_local
);
853 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_ROUTER
,
854 4 * iface
->dhcpv4_router_cnt
, iface
->dhcpv4_router
);
857 if (iface
->dhcpv4_dns_cnt
== 0)
858 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_DNSSERVER
, 4, &iface
->dhcpv4_local
);
860 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_DNSSERVER
,
861 4 * iface
->dhcpv4_dns_cnt
, iface
->dhcpv4_dns
);
864 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_END
, 0, NULL
);
866 struct sockaddr_in dest
= *((struct sockaddr_in
*)addr
);
867 if (req
->giaddr
.s_addr
) {
869 * relay agent is configured, send reply to the agent
871 dest
.sin_addr
= req
->giaddr
;
872 dest
.sin_port
= htons(DHCPV4_SERVER_PORT
);
873 } else if (req
->ciaddr
.s_addr
&& req
->ciaddr
.s_addr
!= dest
.sin_addr
.s_addr
) {
875 * client has existing configuration (ciaddr is set) AND this address is
876 * not the address it used for the dhcp message
878 dest
.sin_addr
= req
->ciaddr
;
879 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
880 } else if ((ntohs(req
->flags
) & DHCPV4_FLAG_BROADCAST
) ||
881 req
->hlen
!= reply
.hlen
|| !reply
.yiaddr
.s_addr
) {
883 * client requests a broadcast reply OR we can't offer an IP
885 dest
.sin_addr
.s_addr
= INADDR_BROADCAST
;
886 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
887 } else if (!req
->ciaddr
.s_addr
&& msg
== DHCPV4_MSG_NAK
) {
889 * client has no previous configuration -> no IP, so we need to reply
890 * with a broadcast packet
892 dest
.sin_addr
.s_addr
= INADDR_BROADCAST
;
893 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
896 * send reply to the newly (in this proccess) allocated IP
898 dest
.sin_addr
= reply
.yiaddr
;
899 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
901 struct arpreq arp
= {.arp_flags
= ATF_COM
};
902 memcpy(arp
.arp_ha
.sa_data
, req
->chaddr
, 6);
903 memcpy(&arp
.arp_pa
, &dest
, sizeof(arp
.arp_pa
));
904 memcpy(arp
.arp_dev
, iface
->ifname
, sizeof(arp
.arp_dev
));
905 ioctl(sock
, SIOCSARP
, &arp
);
908 if (dest
.sin_addr
.s_addr
== INADDR_BROADCAST
)
909 /* reply goes to IP broadcast -> MAC broadcast */
910 syslog(LOG_WARNING
, "sending %s to ff:ff:ff:ff:ff:ff - %s",
911 dhcpv4_msg_to_string(msg
),
912 inet_ntoa(dest
.sin_addr
));
915 * reply is send directly to IP,
916 * MAC is assumed to be the same as the request
918 syslog(LOG_WARNING
, "sending %s to %02x:%02x:%02x:%02x:%02x:%02x - %s",
919 dhcpv4_msg_to_string(msg
),
920 req
->chaddr
[0],req
->chaddr
[1],req
->chaddr
[2],
921 req
->chaddr
[3],req
->chaddr
[4],req
->chaddr
[5],
922 inet_ntoa(dest
.sin_addr
));
924 sendto(sock
, &reply
, sizeof(reply
), MSG_DONTWAIT
,
925 (struct sockaddr
*)&dest
, sizeof(dest
));
928 if (msg
== DHCPV4_MSG_ACK
)
929 ubus_bcast_dhcp_event("dhcp.ack", req
->chaddr
, req
->hlen
, &reply
.yiaddr
,
930 hostname
, iface
->ifname
);
934 static bool dhcpv4_assign(struct interface
*iface
,
935 struct dhcpv4_assignment
*assign
, uint32_t raddr
)
937 uint32_t start
= ntohl(iface
->dhcpv4_start_ip
.s_addr
);
938 uint32_t end
= ntohl(iface
->dhcpv4_end_ip
.s_addr
);
939 uint32_t count
= end
- start
+ 1;
941 // try to assign the IP the client asked for
942 if (start
<= ntohl(raddr
) && ntohl(raddr
) <= end
&&
943 !find_assignment_by_addr(iface
, raddr
)) {
944 assign
->addr
= raddr
;
945 syslog(LOG_INFO
, "assigning the IP the client asked for: %u.%u.%u.%u",
946 ((uint8_t *)&assign
->addr
)[0],
947 ((uint8_t *)&assign
->addr
)[1],
948 ((uint8_t *)&assign
->addr
)[2],
949 ((uint8_t *)&assign
->addr
)[3]);
953 // Seed RNG with checksum of hwaddress
955 for (size_t i
= 0; i
< sizeof(assign
->hwaddr
); ++i
) {
956 // Knuth's multiplicative method
957 uint8_t o
= assign
->hwaddr
[i
];
958 seed
+= (o
*2654435761) % UINT32_MAX
;
963 uint32_t try = (((uint32_t)rand()) % count
) + start
;
965 if (list_empty(&iface
->dhcpv4_assignments
)) {
966 assign
->addr
= htonl(try);
967 syslog(LOG_INFO
, "assigning mapped IP (empty list): %u.%u.%u.%u",
968 ((uint8_t *)&assign
->addr
)[0],
969 ((uint8_t *)&assign
->addr
)[1],
970 ((uint8_t *)&assign
->addr
)[2],
971 ((uint8_t *)&assign
->addr
)[3]);
975 for (uint32_t i
= 0; i
< count
; ++i
) {
976 if (!find_assignment_by_addr(iface
, htonl(try))) {
977 /* test was successful: IP address is not assigned, assign it */
978 assign
->addr
= htonl(try);
979 syslog(LOG_DEBUG
, "assigning mapped IP: %u.%u.%u.%u (try %u of %u)",
980 ((uint8_t *)&assign
->addr
)[0],
981 ((uint8_t *)&assign
->addr
)[1],
982 ((uint8_t *)&assign
->addr
)[2],
983 ((uint8_t *)&assign
->addr
)[3],
987 try = (((try - start
) + 1) % count
) + start
;
990 syslog(LOG_WARNING
, "can't assign any IP address -> address space is full");
995 static struct dhcpv4_assignment
* dhcpv4_lease(struct interface
*iface
,
996 enum dhcpv4_msg msg
, const uint8_t *mac
, const uint32_t reqaddr
,
997 uint32_t *leasetime
, const char *hostname
, const size_t hostname_len
,
998 const bool accept_fr_nonce
, bool *incl_fr_opt
, uint32_t *fr_serverid
)
1000 struct dhcpv4_assignment
*a
= find_assignment_by_hwaddr(iface
, mac
);
1001 struct dhcpv4_assignment
*lease
= NULL
;
1002 time_t now
= odhcpd_time();
1004 if (a
&& (a
->flags
& OAF_BOUND
) && a
->fr_ip
) {
1005 *fr_serverid
= a
->fr_ip
->addr
.addr
.in
.s_addr
;
1009 if (msg
== DHCPV4_MSG_DISCOVER
|| msg
== DHCPV4_MSG_REQUEST
) {
1010 bool assigned
= !!a
;
1013 if (!iface
->no_dynamic_dhcp
) {
1014 /* Create new binding */
1015 a
= calloc(1, sizeof(*a
));
1017 syslog(LOG_ERR
, "Failed to calloc binding on interface %s",
1021 memcpy(a
->hwaddr
, mac
, sizeof(a
->hwaddr
));
1022 /* Don't consider new assignment as infinite */
1023 a
->valid_until
= now
;
1025 assigned
= dhcpv4_assign(iface
, a
, reqaddr
);
1028 list_add(&a
->head
, &iface
->dhcpv4_assignments
);
1031 } else if ((a
->addr
& iface
->dhcpv4_mask
.s_addr
) !=
1032 (iface
->dhcpv4_start_ip
.s_addr
& iface
->dhcpv4_mask
.s_addr
)) {
1035 assigned
= dhcpv4_assign(iface
, a
, reqaddr
);
1037 list_add(&a
->head
, &iface
->dhcpv4_assignments
);
1041 uint32_t my_leasetime
;
1044 my_leasetime
= a
->leasetime
;
1046 my_leasetime
= iface
->dhcpv4_leasetime
;
1048 if ((*leasetime
== 0) || (my_leasetime
< *leasetime
))
1049 *leasetime
= my_leasetime
;
1051 if (msg
== DHCPV4_MSG_DISCOVER
) {
1052 a
->flags
&= ~OAF_BOUND
;
1054 *incl_fr_opt
= accept_fr_nonce
;
1055 if (!(a
->flags
& OAF_STATIC
))
1056 a
->valid_until
= now
;
1058 if (hostname_len
> 0) {
1059 a
->hostname
= realloc(a
->hostname
, hostname_len
+ 1);
1061 memcpy(a
->hostname
, hostname
, hostname_len
);
1062 a
->hostname
[hostname_len
] = 0;
1066 if (!(a
->flags
& OAF_BOUND
)) {
1067 a
->accept_fr_nonce
= accept_fr_nonce
;
1068 *incl_fr_opt
= accept_fr_nonce
;
1069 odhcpd_urandom(a
->key
, sizeof(a
->key
));
1070 a
->flags
|= OAF_BOUND
;
1072 *incl_fr_opt
= false;
1074 if (!(a
->flags
& OAF_STATIC
))
1075 a
->valid_until
= ((*leasetime
== UINT32_MAX
) ? 0 : (time_t)(now
+ *leasetime
));
1077 } else if (!assigned
&& a
) {
1078 /* Cleanup failed assignment */
1079 free_dhcpv4_assignment(a
);
1085 } else if (msg
== DHCPV4_MSG_RELEASE
&& a
) {
1086 a
->flags
&= ~OAF_BOUND
;
1088 if (!(a
->flags
& OAF_STATIC
))
1089 a
->valid_until
= now
- 1;
1091 } else if (msg
== DHCPV4_MSG_DECLINE
&& a
) {
1092 a
->flags
&= ~OAF_BOUND
;
1094 if (!(a
->flags
& OAF_STATIC
)) {
1095 memset(a
->hwaddr
, 0, sizeof(a
->hwaddr
));
1096 a
->valid_until
= now
+ 3600; /* Block address for 1h */
1100 dhcpv6_write_statefile();