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 bool addr_is_fr_ip(struct interface
*iface
, struct in_addr
*addr
);
41 static void valid_until_cb(struct uloop_timeout
*event
);
42 static void handle_addrlist_change(struct interface
*iface
);
43 static void dhcpv4_fr_start(struct dhcp_assignment
*a
);
44 static void dhcpv4_fr_rand_delay(struct dhcp_assignment
*a
);
45 static void dhcpv4_fr_stop(struct dhcp_assignment
*a
);
46 static void handle_dhcpv4(void *addr
, void *data
, size_t len
,
47 struct interface
*iface
, void *dest_addr
);
48 static struct dhcp_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
);
159 } else if (iface
->dhcpv4_assignments
.next
) {
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_WARNING
, "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 iface
->dhcpv4_start_ip
.s_addr
= htonl(start
) |
240 (addr
->s_addr
& mask
.s_addr
);
241 iface
->dhcpv4_end_ip
.s_addr
= htonl(end
) |
242 (addr
->s_addr
& mask
.s_addr
);
243 iface
->dhcpv4_local
= *addr
;
244 iface
->dhcpv4_bcast
= iface
->addr4
[i
].broadcast
;
245 iface
->dhcpv4_mask
= mask
;
250 /* Don't allocate IP range for subnets bigger than 28 */
251 if (iface
->addr4
[0].prefix
> 28) {
252 syslog(LOG_WARNING
, "Auto allocation of DHCP range fails on %s", iface
->name
);
256 iface
->dhcpv4_local
= iface
->addr4
[0].addr
.in
;
257 iface
->dhcpv4_bcast
= iface
->addr4
[0].broadcast
;
258 odhcpd_bitlen2netmask(false, iface
->addr4
[0].prefix
, &iface
->dhcpv4_mask
);
259 end
= start
= iface
->dhcpv4_local
.s_addr
& iface
->dhcpv4_mask
.s_addr
;
261 /* Auto allocate ranges */
262 if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffff00) {
263 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(100);
264 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(250);
265 } else if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffffc0) {
266 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(10);
267 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(60);
268 } else if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffffe0) {
269 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(10);
270 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(30);
272 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(3);
273 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(12);
279 static void inc_ref_cnt_ip(struct odhcpd_ref_ip
**ptr
, struct odhcpd_ref_ip
*ip
)
285 static void decr_ref_cnt_ip(struct odhcpd_ref_ip
**ptr
, struct interface
*iface
)
287 struct odhcpd_ref_ip
*ip
= *ptr
;
289 if (--ip
->ref_cnt
== 0) {
290 netlink_setup_addr(&ip
->addr
, iface
->ifindex
, false, false);
299 static bool addr_is_fr_ip(struct interface
*iface
, struct in_addr
*addr
)
301 struct odhcpd_ref_ip
*p
;
303 list_for_each_entry(p
, &iface
->dhcpv4_fr_ips
, head
) {
304 if (addr
->s_addr
== p
->addr
.addr
.in
.s_addr
)
311 static bool leases_require_fr(struct interface
*iface
, struct odhcpd_ipaddr
*addr
,
314 struct dhcp_assignment
*a
= NULL
;
315 struct odhcpd_ref_ip
*fr_ip
= NULL
;
317 list_for_each_entry(a
, &iface
->dhcpv4_assignments
, head
) {
318 if ((a
->accept_fr_nonce
|| iface
->dhcpv4_forcereconf
) &&
320 ((a
->addr
& mask
) == (addr
->addr
.in
.s_addr
& mask
))) {
322 fr_ip
= calloc(1, sizeof(*fr_ip
));
326 list_add(&fr_ip
->head
, &iface
->dhcpv4_fr_ips
);
329 inc_ref_cnt_ip(&a
->fr_ip
, fr_ip
);
333 return fr_ip
? true : false;
336 static void valid_until_cb(struct uloop_timeout
*event
)
338 struct interface
*iface
;
339 time_t now
= odhcpd_time();
341 avl_for_each_element(&interfaces
, iface
, avl
) {
342 if (iface
->dhcpv4
!= MODE_SERVER
|| iface
->dhcpv4_assignments
.next
== NULL
)
345 struct dhcp_assignment
*a
, *n
;
346 list_for_each_entry_safe(a
, n
, &iface
->dhcpv4_assignments
, head
) {
347 if (!INFINITE_VALID(a
->valid_until
) && a
->valid_until
< now
)
351 uloop_timeout_set(event
, 1000);
354 static void handle_addrlist_change(struct interface
*iface
)
356 struct odhcpd_ipaddr ip
;
357 struct odhcpd_ref_ip
*a
;
358 struct dhcp_assignment
*c
;
359 uint32_t mask
= iface
->dhcpv4_mask
.s_addr
;
361 memset(&ip
, 0, sizeof(ip
));
362 ip
.addr
.in
= iface
->dhcpv4_local
;
363 ip
.prefix
= odhcpd_netmask2bitlen(false, &iface
->dhcpv4_mask
);
364 ip
.broadcast
= iface
->dhcpv4_bcast
;
366 setup_dhcpv4_addresses(iface
);
368 if ((ip
.addr
.in
.s_addr
& mask
) ==
369 (iface
->dhcpv4_local
.s_addr
& iface
->dhcpv4_mask
.s_addr
))
372 if (ip
.addr
.in
.s_addr
&& !leases_require_fr(iface
, &ip
, mask
))
375 if (iface
->dhcpv4_local
.s_addr
== INADDR_ANY
|| list_empty(&iface
->dhcpv4_fr_ips
))
378 a
= list_first_entry(&iface
->dhcpv4_fr_ips
, struct odhcpd_ref_ip
, head
);
380 if (netlink_setup_addr(&a
->addr
, iface
->ifindex
, false, true)) {
381 syslog(LOG_ERR
, "Failed to add ip address on %s", iface
->name
);
385 list_for_each_entry(c
, &iface
->dhcpv4_assignments
, head
) {
386 if ((c
->flags
& OAF_BOUND
) && c
->fr_ip
&& !c
->fr_cnt
) {
387 if (c
->accept_fr_nonce
|| iface
->dhcpv4_forcereconf
)
388 dhcpv4_fr_rand_delay(c
);
395 static char *dhcpv4_msg_to_string(uint8_t reqmsg
)
398 case (DHCPV4_MSG_DISCOVER
):
399 return "DHCPV4_MSG_DISCOVER";
400 case (DHCPV4_MSG_OFFER
):
401 return "DHCPV4_MSG_OFFER";
402 case (DHCPV4_MSG_REQUEST
):
403 return "DHCPV4_MSG_REQUEST";
404 case (DHCPV4_MSG_DECLINE
):
405 return "DHCPV4_MSG_DECLINE";
406 case (DHCPV4_MSG_ACK
):
407 return "DHCPV4_MSG_ACK";
408 case (DHCPV4_MSG_NAK
):
409 return "DHCPV4_MSG_NAK";
410 case (DHCPV4_MSG_RELEASE
):
411 return "DHCPV4_MSG_RELEASE";
412 case (DHCPV4_MSG_INFORM
):
413 return "DHCPV4_MSG_INFORM";
414 case (DHCPV4_MSG_FORCERENEW
):
415 return "DHCPV4_MSG_FORCERENEW";
421 static void dhcpv4_free_assignment(struct dhcp_assignment
*a
)
427 static void dhcpv4_put(struct dhcpv4_message
*msg
, uint8_t **cookie
,
428 uint8_t type
, uint8_t len
, const void *data
)
430 uint8_t *c
= *cookie
;
431 uint8_t *end
= (uint8_t *)msg
+ sizeof(*msg
);
433 if (*cookie
+ 2 + len
> end
)
438 memcpy(c
, data
, len
);
443 static void dhcpv4_fr_send(struct dhcp_assignment
*a
)
445 struct dhcpv4_message fr_msg
= {
446 .op
= DHCPV4_BOOTREPLY
,
452 .ciaddr
= {INADDR_ANY
},
453 .yiaddr
= {INADDR_ANY
},
454 .siaddr
= {INADDR_ANY
},
455 .giaddr
= {INADDR_ANY
},
460 struct dhcpv4_auth_forcerenew
*auth_o
, auth
= {
464 .replay
= {htonl(time(NULL
)), htonl(++serial
)},
468 struct interface
*iface
= a
->iface
;
470 odhcpd_urandom(&fr_msg
.xid
, sizeof(fr_msg
.xid
));
471 memcpy(fr_msg
.chaddr
, a
->hwaddr
, fr_msg
.hlen
);
473 fr_msg
.options
[0] = 0x63;
474 fr_msg
.options
[1] = 0x82;
475 fr_msg
.options
[2] = 0x53;
476 fr_msg
.options
[3] = 0x63;
478 uint8_t *cookie
= &fr_msg
.options
[4];
479 uint8_t msg
= DHCPV4_MSG_FORCERENEW
;
481 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_MESSAGE
, 1, &msg
);
482 if (a
->accept_fr_nonce
) {
483 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_AUTHENTICATION
, sizeof(auth
), &auth
);
484 auth_o
= (struct dhcpv4_auth_forcerenew
*)(cookie
- sizeof(auth
));
485 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_END
, 0, NULL
);
488 uint8_t secretbytes
[64];
489 memset(secretbytes
, 0, sizeof(secretbytes
));
490 memcpy(secretbytes
, a
->key
, sizeof(a
->key
));
492 for (size_t i
= 0; i
< sizeof(secretbytes
); ++i
)
493 secretbytes
[i
] ^= 0x36;
496 md5_hash(secretbytes
, sizeof(secretbytes
), &md5
);
497 md5_hash(&fr_msg
, sizeof(fr_msg
), &md5
);
498 md5_end(auth_o
->key
, &md5
);
500 for (size_t i
= 0; i
< sizeof(secretbytes
); ++i
) {
501 secretbytes
[i
] ^= 0x36;
502 secretbytes
[i
] ^= 0x5c;
506 md5_hash(secretbytes
, sizeof(secretbytes
), &md5
);
507 md5_hash(auth_o
->key
, sizeof(auth_o
->key
), &md5
);
508 md5_end(auth_o
->key
, &md5
);
510 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_SERVERID
, 4,
511 &a
->fr_ip
->addr
.addr
.in
.s_addr
);
512 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_END
, 0, NULL
);
515 struct sockaddr_in dest
;
516 memset(&dest
, 0, sizeof(dest
));
517 dest
.sin_family
= AF_INET
;
518 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
519 dest
.sin_addr
.s_addr
= a
->addr
;
521 if (sendto(iface
->dhcpv4_event
.uloop
.fd
, &fr_msg
, sizeof(fr_msg
),
522 MSG_DONTWAIT
, (struct sockaddr
*)&dest
, sizeof(dest
)) < 0)
523 syslog(LOG_ERR
, "Failed to send %s to %s - %s: %m", dhcpv4_msg_to_string(msg
),
524 odhcpd_print_mac(a
->hwaddr
, sizeof(a
->hwaddr
)), inet_ntoa(dest
.sin_addr
));
526 syslog(LOG_WARNING
, "Sent %s to %s - %s", dhcpv4_msg_to_string(msg
),
527 odhcpd_print_mac(a
->hwaddr
, sizeof(a
->hwaddr
)), inet_ntoa(dest
.sin_addr
));
530 static void dhcpv4_fr_timer(struct uloop_timeout
*event
)
532 struct dhcp_assignment
*a
= container_of(event
, struct dhcp_assignment
, fr_timer
);
534 if (a
->fr_cnt
> 0 && a
->fr_cnt
< 8) {
536 uloop_timeout_set(&a
->fr_timer
, 1000 << a
->fr_cnt
);
542 static void dhcpv4_fr_start(struct dhcp_assignment
*a
)
544 uloop_timeout_set(&a
->fr_timer
, 1000 << a
->fr_cnt
);
545 a
->fr_timer
.cb
= dhcpv4_fr_timer
;
551 static void dhcpv4_fr_delay_timer(struct uloop_timeout
*event
)
553 struct dhcp_assignment
*a
= container_of(event
, struct dhcp_assignment
, fr_timer
);
554 struct interface
*iface
= a
->iface
;
556 (iface
->dhcpv4_event
.uloop
.fd
== -1 ? dhcpv4_fr_rand_delay(a
) : dhcpv4_fr_start(a
));
559 static void dhcpv4_fr_rand_delay(struct dhcp_assignment
*a
)
561 #define MIN_DELAY 500
565 odhcpd_urandom(&msecs
, sizeof(msecs
));
567 msecs
= labs(msecs
)%MAX_FUZZ
+ MIN_DELAY
;
569 uloop_timeout_set(&a
->fr_timer
, msecs
);
570 a
->fr_timer
.cb
= dhcpv4_fr_delay_timer
;
573 static void dhcpv4_fr_stop(struct dhcp_assignment
*a
)
575 uloop_timeout_cancel(&a
->fr_timer
);
576 decr_ref_cnt_ip(&a
->fr_ip
, a
->iface
);
578 a
->fr_timer
.cb
= NULL
;
581 /* Handler for DHCPv4 messages */
582 static void handle_dhcpv4(void *addr
, void *data
, size_t len
,
583 struct interface
*iface
, _unused
void *dest_addr
)
585 struct dhcpv4_message
*req
= data
;
590 if (len
< offsetof(struct dhcpv4_message
, options
) + 4 ||
591 req
->op
!= DHCPV4_BOOTREQUEST
|| req
->hlen
!= 6)
594 syslog(LOG_NOTICE
, "Got DHCPv4 request on %s", iface
->name
);
596 if (!iface
->dhcpv4_start_ip
.s_addr
&& !iface
->dhcpv4_end_ip
.s_addr
) {
597 syslog(LOG_WARNING
, "No DHCP range available on %s", iface
->name
);
601 int sock
= iface
->dhcpv4_event
.uloop
.fd
;
603 struct dhcpv4_message reply
= {
604 .op
= DHCPV4_BOOTREPLY
,
611 .ciaddr
= {INADDR_ANY
},
612 .giaddr
= req
->giaddr
,
613 .siaddr
= iface
->dhcpv4_local
,
615 memcpy(reply
.chaddr
, req
->chaddr
, sizeof(reply
.chaddr
));
617 reply
.options
[0] = 0x63;
618 reply
.options
[1] = 0x82;
619 reply
.options
[2] = 0x53;
620 reply
.options
[3] = 0x63;
622 uint8_t *cookie
= &reply
.options
[4];
623 uint8_t reqmsg
= DHCPV4_MSG_REQUEST
;
624 uint8_t msg
= DHCPV4_MSG_ACK
;
626 uint32_t reqaddr
= INADDR_ANY
;
627 uint32_t leasetime
= 0;
628 size_t hostname_len
= 0;
630 bool accept_fr_nonce
= false;
631 bool incl_fr_opt
= false;
633 uint8_t *start
= &req
->options
[4];
634 uint8_t *end
= ((uint8_t*)data
) + len
;
635 struct dhcpv4_option
*opt
;
636 dhcpv4_for_each_option(start
, end
, opt
) {
637 if (opt
->type
== DHCPV4_OPT_MESSAGE
&& opt
->len
== 1)
638 reqmsg
= opt
->data
[0];
639 else if (opt
->type
== DHCPV4_OPT_HOSTNAME
&& opt
->len
> 0) {
640 hostname_len
= opt
->len
;
641 memcpy(hostname
, opt
->data
, hostname_len
);
642 hostname
[hostname_len
] = 0;
643 } else if (opt
->type
== DHCPV4_OPT_IPADDRESS
&& opt
->len
== 4)
644 memcpy(&reqaddr
, opt
->data
, 4);
645 else if (opt
->type
== DHCPV4_OPT_SERVERID
&& opt
->len
== 4) {
646 if (memcmp(opt
->data
, &iface
->dhcpv4_local
, 4))
648 } else if (iface
->filter_class
&& opt
->type
== DHCPV4_OPT_USER_CLASS
) {
649 uint8_t *c
= opt
->data
, *cend
= &opt
->data
[opt
->len
];
650 for (; c
< cend
&& &c
[*c
] < cend
; c
= &c
[1 + *c
]) {
651 size_t elen
= strlen(iface
->filter_class
);
652 if (*c
== elen
&& !memcmp(&c
[1], iface
->filter_class
, elen
))
653 return; // Ignore from homenet
655 } else if (opt
->type
== DHCPV4_OPT_LEASETIME
&& opt
->len
== 4)
656 memcpy(&leasetime
, opt
->data
, 4);
657 else if (opt
->type
== DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE
&& opt
->len
> 0) {
658 for (uint8_t i
= 0; i
< opt
->len
; i
++) {
659 if (opt
->data
[i
] == 1) {
660 accept_fr_nonce
= true;
668 if (reqmsg
!= DHCPV4_MSG_DISCOVER
&& reqmsg
!= DHCPV4_MSG_REQUEST
&&
669 reqmsg
!= DHCPV4_MSG_INFORM
&& reqmsg
!= DHCPV4_MSG_DECLINE
&&
670 reqmsg
!= DHCPV4_MSG_RELEASE
)
673 struct dhcp_assignment
*a
= NULL
;
674 uint32_t serverid
= iface
->dhcpv4_local
.s_addr
;
675 uint32_t fr_serverid
= INADDR_ANY
;
677 if (reqmsg
!= DHCPV4_MSG_INFORM
)
678 a
= dhcpv4_lease(iface
, reqmsg
, req
->chaddr
, reqaddr
,
679 &leasetime
, hostname
, hostname_len
,
680 accept_fr_nonce
, &incl_fr_opt
, &fr_serverid
);
683 if (reqmsg
== DHCPV4_MSG_REQUEST
)
684 msg
= DHCPV4_MSG_NAK
;
685 else if (reqmsg
== DHCPV4_MSG_DISCOVER
)
687 } else if (reqmsg
== DHCPV4_MSG_DISCOVER
)
688 msg
= DHCPV4_MSG_OFFER
;
689 else if (reqmsg
== DHCPV4_MSG_REQUEST
&&
690 ((reqaddr
&& reqaddr
!= a
->addr
) ||
691 (req
->ciaddr
.s_addr
&& req
->ciaddr
.s_addr
!= a
->addr
))) {
692 msg
= DHCPV4_MSG_NAK
;
694 * DHCP client requested an IP which we can't offer to him. Probably the
695 * client changed the network or the network has been changed. The reply
696 * type is set to DHCPV4_MSG_NAK, because the client should not use that IP.
698 * For modern devices we build an answer that includes a valid IP, like
699 * a DHCPV4_MSG_ACK. The client will use that IP and doesn't need to
700 * perform additional DHCP round trips.
706 * Buggy clients do serverid checking in nack messages; therefore set the
707 * serverid in nack messages triggered by a previous force renew equal to
708 * the server id in use at that time by the server
712 serverid
= fr_serverid
;
714 if (req
->ciaddr
.s_addr
&&
715 ((iface
->dhcpv4_start_ip
.s_addr
& iface
->dhcpv4_mask
.s_addr
) !=
716 (req
->ciaddr
.s_addr
& iface
->dhcpv4_mask
.s_addr
)))
717 req
->ciaddr
.s_addr
= INADDR_ANY
;
720 syslog(LOG_WARNING
, "Received %s from %s on %s", dhcpv4_msg_to_string(reqmsg
),
721 odhcpd_print_mac(req
->chaddr
, req
->hlen
), iface
->name
);
724 if (reqmsg
== DHCPV4_MSG_RELEASE
)
725 ubus_bcast_dhcp_event("dhcp.release", req
->chaddr
, req
->hlen
,
726 &req
->ciaddr
, hostname
, iface
->ifname
);
728 if (reqmsg
== DHCPV4_MSG_DECLINE
|| reqmsg
== DHCPV4_MSG_RELEASE
)
731 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_MESSAGE
, 1, &msg
);
732 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_SERVERID
, 4, &serverid
);
737 reply
.yiaddr
.s_addr
= a
->addr
;
739 val
= htonl(leasetime
);
740 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_LEASETIME
, 4, &val
);
742 if (leasetime
!= UINT32_MAX
) {
743 val
= htonl(500 * leasetime
/ 1000);
744 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_RENEW
, 4, &val
);
746 val
= htonl(875 * leasetime
/ 1000);
747 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_REBIND
, 4, &val
);
750 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_NETMASK
, 4,
751 &iface
->dhcpv4_mask
.s_addr
);
754 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_HOSTNAME
,
755 strlen(a
->hostname
), a
->hostname
);
757 if (iface
->dhcpv4_bcast
.s_addr
!= INADDR_ANY
)
758 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_BROADCAST
, 4, &iface
->dhcpv4_bcast
);
761 if (reqmsg
== DHCPV4_MSG_REQUEST
) {
762 struct dhcpv4_auth_forcerenew auth
= {
766 .replay
= {htonl(time(NULL
)), htonl(++serial
)},
771 memcpy(auth
.key
, a
->key
, sizeof(auth
.key
));
772 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_AUTHENTICATION
, sizeof(auth
), &auth
);
775 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE
,
783 memset(&ifr
, 0, sizeof(ifr
));
784 strncpy(ifr
.ifr_name
, iface
->ifname
, sizeof(ifr
.ifr_name
) - 1);
786 if (!ioctl(sock
, SIOCGIFMTU
, &ifr
)) {
787 uint16_t mtu
= htons(ifr
.ifr_mtu
);
788 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_MTU
, 2, &mtu
);
791 if (iface
->search
&& iface
->search_len
<= 255)
792 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_SEARCH_DOMAIN
,
793 iface
->search_len
, iface
->search
);
794 else if (!res_init() && _res
.dnsrch
[0] && _res
.dnsrch
[0][0]) {
795 uint8_t search_buf
[256];
796 int len
= dn_comp(_res
.dnsrch
[0], search_buf
,
797 sizeof(search_buf
), NULL
, NULL
);
799 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_SEARCH_DOMAIN
,
803 if (iface
->dhcpv4_router_cnt
== 0)
804 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_ROUTER
, 4, &iface
->dhcpv4_local
);
806 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_ROUTER
,
807 4 * iface
->dhcpv4_router_cnt
, iface
->dhcpv4_router
);
810 if (iface
->dhcpv4_dns_cnt
== 0)
811 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_DNSSERVER
, 4, &iface
->dhcpv4_local
);
813 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_DNSSERVER
,
814 4 * iface
->dhcpv4_dns_cnt
, iface
->dhcpv4_dns
);
817 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_END
, 0, NULL
);
819 struct sockaddr_in dest
= *((struct sockaddr_in
*)addr
);
820 if (req
->giaddr
.s_addr
) {
822 * relay agent is configured, send reply to the agent
824 dest
.sin_addr
= req
->giaddr
;
825 dest
.sin_port
= htons(DHCPV4_SERVER_PORT
);
826 } else if (req
->ciaddr
.s_addr
&& req
->ciaddr
.s_addr
!= dest
.sin_addr
.s_addr
) {
828 * client has existing configuration (ciaddr is set) AND this address is
829 * not the address it used for the dhcp message
831 dest
.sin_addr
= req
->ciaddr
;
832 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
833 } else if ((ntohs(req
->flags
) & DHCPV4_FLAG_BROADCAST
) ||
834 req
->hlen
!= reply
.hlen
|| !reply
.yiaddr
.s_addr
) {
836 * client requests a broadcast reply OR we can't offer an IP
838 dest
.sin_addr
.s_addr
= INADDR_BROADCAST
;
839 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
840 } else if (!req
->ciaddr
.s_addr
&& msg
== DHCPV4_MSG_NAK
) {
842 * client has no previous configuration -> no IP, so we need to reply
843 * with a broadcast packet
845 dest
.sin_addr
.s_addr
= INADDR_BROADCAST
;
846 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
848 struct arpreq arp
= {.arp_flags
= ATF_COM
};
851 * send reply to the newly (in this proccess) allocated IP
853 dest
.sin_addr
= reply
.yiaddr
;
854 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
856 memcpy(arp
.arp_ha
.sa_data
, req
->chaddr
, 6);
857 memcpy(&arp
.arp_pa
, &dest
, sizeof(arp
.arp_pa
));
858 memcpy(arp
.arp_dev
, iface
->ifname
, sizeof(arp
.arp_dev
));
860 if (ioctl(sock
, SIOCSARP
, &arp
) < 0)
861 syslog(LOG_ERR
, "ioctl(SIOCSARP): %m");
864 if (sendto(sock
, &reply
, sizeof(reply
), MSG_DONTWAIT
,
865 (struct sockaddr
*)&dest
, sizeof(dest
)) < 0)
866 syslog(LOG_ERR
, "Failed to send %s to %s - %s: %m",
867 dhcpv4_msg_to_string(msg
),
868 dest
.sin_addr
.s_addr
== INADDR_BROADCAST
?
869 "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req
->chaddr
, req
->hlen
),
870 inet_ntoa(dest
.sin_addr
));
872 syslog(LOG_ERR
, "Sent %s to %s - %s",
873 dhcpv4_msg_to_string(msg
),
874 dest
.sin_addr
.s_addr
== INADDR_BROADCAST
?
875 "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req
->chaddr
, req
->hlen
),
876 inet_ntoa(dest
.sin_addr
));
880 if (msg
== DHCPV4_MSG_ACK
)
881 ubus_bcast_dhcp_event("dhcp.ack", req
->chaddr
, req
->hlen
, &reply
.yiaddr
,
882 hostname
, iface
->ifname
);
886 static bool dhcpv4_assign(struct interface
*iface
, struct dhcp_assignment
*a
,
889 struct dhcp_assignment
*c
;
890 uint32_t start
= ntohl(iface
->dhcpv4_start_ip
.s_addr
);
891 uint32_t end
= ntohl(iface
->dhcpv4_end_ip
.s_addr
);
892 uint32_t count
= end
- start
+ 1;
895 /* Preconfigured IP address by static lease */
897 if (list_empty(&iface
->dhcpv4_assignments
)) {
898 list_add(&a
->head
, &iface
->dhcpv4_assignments
);
902 list_for_each_entry(c
, &iface
->dhcpv4_assignments
, head
) {
903 if (ntohl(c
->addr
) > ntohl(a
->addr
)) {
904 list_add_tail(&a
->head
, &c
->head
);
906 } else if (ntohl(a
->addr
) == ntohl(c
->addr
))
911 /* try to assign the IP the client asked for */
912 if (start
<= ntohl(raddr
) && ntohl(raddr
) <= end
&&
913 !config_find_lease_by_ipaddr(raddr
)) {
914 if (list_empty(&iface
->dhcpv4_assignments
)) {
915 list_add(&a
->head
, &iface
->dhcpv4_assignments
);
919 list_for_each_entry(c
, &iface
->dhcpv4_assignments
, head
) {
920 if (ntohl(raddr
) == ntohl(c
->addr
))
923 if (ntohl(c
->addr
) > ntohl(raddr
) || list_is_last(&c
->head
, &iface
->dhcpv4_assignments
)) {
924 list_add_tail(&a
->head
,
925 ntohl(c
->addr
) > ntohl(raddr
) ? &c
->head
: &iface
->dhcpv4_assignments
);
929 syslog(LOG_INFO
, "Assigning the IP the client asked for: %u.%u.%u.%u",
930 ((uint8_t *)&a
->addr
)[0], ((uint8_t *)&a
->addr
)[1],
931 ((uint8_t *)&a
->addr
)[2], ((uint8_t *)&a
->addr
)[3]);
938 /* Seed RNG with checksum of hwaddress */
939 for (size_t i
= 0; i
< sizeof(a
->hwaddr
); ++i
) {
940 /* Knuth's multiplicative method */
941 uint8_t o
= a
->hwaddr
[i
];
942 seed
+= (o
*2654435761) % UINT32_MAX
;
947 for (uint32_t i
= 0, try = (((uint32_t)rand()) % count
) + start
; i
< count
;
948 ++i
, try = (((try - start
) + 1) % count
) + start
) {
950 if (config_find_lease_by_ipaddr(htonl(try)))
953 if (list_empty(&iface
->dhcpv4_assignments
)) {
954 list_add(&a
->head
, &iface
->dhcpv4_assignments
);
955 a
->addr
= htonl(try);
957 syslog(LOG_INFO
, "Assigning mapped IP (empty list): %u.%u.%u.%u",
958 ((uint8_t *)&a
->addr
)[0], ((uint8_t *)&a
->addr
)[1],
959 ((uint8_t *)&a
->addr
)[2], ((uint8_t *)&a
->addr
)[3]);
964 list_for_each_entry(c
, &iface
->dhcpv4_assignments
, head
) {
965 if (try == ntohl(c
->addr
))
968 if (ntohl(c
->addr
) > try || list_is_last(&c
->head
, &iface
->dhcpv4_assignments
)) {
969 list_add_tail(&a
->head
,
970 ntohl(c
->addr
) > try ? &c
->head
: &iface
->dhcpv4_assignments
);
971 a
->addr
= htonl(try);
973 syslog(LOG_DEBUG
, "Assigning mapped IP: %u.%u.%u.%u (try %u of %u)",
974 ((uint8_t *)&a
->addr
)[0], ((uint8_t *)&a
->addr
)[1],
975 ((uint8_t *)&a
->addr
)[2], ((uint8_t *)&a
->addr
)[3],
983 syslog(LOG_WARNING
, "Can't assign any IP address -> address space is full");
988 static struct dhcp_assignment
*
989 dhcpv4_lease(struct interface
*iface
, enum dhcpv4_msg msg
, const uint8_t *mac
,
990 const uint32_t reqaddr
, uint32_t *leasetime
, const char *hostname
,
991 const size_t hostname_len
, const bool accept_fr_nonce
, bool *incl_fr_opt
,
992 uint32_t *fr_serverid
)
994 struct dhcp_assignment
*a
= find_assignment_by_hwaddr(iface
, mac
);
995 struct lease
*l
= config_find_lease_by_mac(mac
);
996 time_t now
= odhcpd_time();
998 if (l
&& a
&& a
->lease
!= l
) {
1003 if (a
&& (a
->flags
& OAF_BOUND
) && a
->fr_ip
) {
1004 *fr_serverid
= a
->fr_ip
->addr
.addr
.in
.s_addr
;
1008 if (msg
== DHCPV4_MSG_DISCOVER
|| msg
== DHCPV4_MSG_REQUEST
) {
1009 bool assigned
= !!a
;
1012 if (!iface
->no_dynamic_dhcp
|| l
) {
1013 /* Create new binding */
1014 a
= calloc(1, sizeof(*a
));
1016 syslog(LOG_ERR
, "Failed to calloc binding on interface %s",
1020 memcpy(a
->hwaddr
, mac
, sizeof(a
->hwaddr
));
1021 /* Set valid time to 0 for static lease indicating */
1022 /* infinite lifetime otherwise current time */
1023 a
->valid_until
= l
? 0 : now
;
1024 a
->dhcp_free_cb
= dhcpv4_free_assignment
;
1026 a
->flags
= OAF_DHCPV4
;
1027 a
->addr
= l
? l
->ipaddr
: INADDR_ANY
;
1029 assigned
= dhcpv4_assign(iface
, a
, reqaddr
);
1032 a
->flags
|= OAF_STATIC
;
1035 a
->hostname
= strdup(l
->hostname
);
1038 a
->leasetime
= l
->leasetime
;
1040 list_add(&a
->lease_list
, &l
->assignments
);
1044 } else if (((a
->addr
& iface
->dhcpv4_mask
.s_addr
) !=
1045 (iface
->dhcpv4_start_ip
.s_addr
& iface
->dhcpv4_mask
.s_addr
)) &&
1046 !(a
->flags
& OAF_STATIC
)) {
1048 a
->addr
= INADDR_ANY
;
1050 assigned
= dhcpv4_assign(iface
, a
, reqaddr
);
1054 uint32_t my_leasetime
;
1057 my_leasetime
= a
->leasetime
;
1059 my_leasetime
= iface
->dhcpv4_leasetime
;
1061 if ((*leasetime
== 0) || (my_leasetime
< *leasetime
))
1062 *leasetime
= my_leasetime
;
1064 if (msg
== DHCPV4_MSG_DISCOVER
) {
1065 a
->flags
&= ~OAF_BOUND
;
1067 *incl_fr_opt
= accept_fr_nonce
;
1068 if (!(a
->flags
& OAF_STATIC
))
1069 a
->valid_until
= now
;
1071 if ((!(a
->flags
& OAF_STATIC
) || !a
->hostname
) && hostname_len
> 0) {
1072 a
->hostname
= realloc(a
->hostname
, hostname_len
+ 1);
1074 memcpy(a
->hostname
, hostname
, hostname_len
);
1075 a
->hostname
[hostname_len
] = 0;
1077 if (odhcpd_valid_hostname(a
->hostname
))
1078 a
->flags
&= ~OAF_BROKEN_HOSTNAME
;
1080 a
->flags
|= OAF_BROKEN_HOSTNAME
;
1084 if (!(a
->flags
& OAF_BOUND
)) {
1085 a
->accept_fr_nonce
= accept_fr_nonce
;
1086 *incl_fr_opt
= accept_fr_nonce
;
1087 odhcpd_urandom(a
->key
, sizeof(a
->key
));
1088 a
->flags
|= OAF_BOUND
;
1090 *incl_fr_opt
= false;
1092 if (!(a
->flags
& OAF_STATIC
))
1093 a
->valid_until
= ((*leasetime
== UINT32_MAX
) ? 0 : (time_t)(now
+ *leasetime
));
1095 } else if (!assigned
&& a
) {
1096 /* Cleanup failed assignment */
1101 } else if (msg
== DHCPV4_MSG_RELEASE
&& a
) {
1102 a
->flags
&= ~OAF_BOUND
;
1104 if (!(a
->flags
& OAF_STATIC
))
1105 a
->valid_until
= now
- 1;
1107 } else if (msg
== DHCPV4_MSG_DECLINE
&& a
) {
1108 a
->flags
&= ~OAF_BOUND
;
1110 if (!(a
->flags
& OAF_STATIC
)) {
1111 memset(a
->hwaddr
, 0, sizeof(a
->hwaddr
));
1112 a
->valid_until
= now
+ 3600; /* Block address for 1h */
1116 dhcpv6_ia_write_statefile();