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)
40 #define MAX_PREFIX_LEN 28
42 static void dhcpv4_netevent_cb(unsigned long event
, struct netevent_handler_info
*info
);
43 static int setup_dhcpv4_addresses(struct interface
*iface
);
44 static bool addr_is_fr_ip(struct interface
*iface
, struct in_addr
*addr
);
45 static void valid_until_cb(struct uloop_timeout
*event
);
46 static void handle_addrlist_change(struct interface
*iface
);
47 static void dhcpv4_fr_start(struct dhcp_assignment
*a
);
48 static void dhcpv4_fr_rand_delay(struct dhcp_assignment
*a
);
49 static void dhcpv4_fr_stop(struct dhcp_assignment
*a
);
50 static void handle_dhcpv4(void *addr
, void *data
, size_t len
,
51 struct interface
*iface
, void *dest_addr
);
52 static struct dhcp_assignment
* dhcpv4_lease(struct interface
*iface
,
53 enum dhcpv4_msg msg
, const uint8_t *mac
, const uint32_t reqaddr
,
54 uint32_t *leasetime
, const char *hostname
, const size_t hostname_len
,
55 const bool accept_fr_nonce
, bool *incl_fr_opt
, uint32_t *fr_serverid
,
56 const char *reqopts
, const size_t reqopts_len
);
58 static struct netevent_handler dhcpv4_netevent_handler
= { .cb
= dhcpv4_netevent_cb
, };
59 static struct uloop_timeout valid_until_timeout
= {.cb
= valid_until_cb
};
60 static uint32_t serial
= 0;
62 struct odhcpd_ref_ip
{
63 struct list_head head
;
65 struct odhcpd_ipaddr addr
;
68 /* Create socket and register events */
71 uloop_timeout_set(&valid_until_timeout
, 1000);
72 netlink_add_netevent_handler(&dhcpv4_netevent_handler
);
77 int dhcpv4_setup_interface(struct interface
*iface
, bool enable
)
81 enable
= enable
&& (iface
->dhcpv4
!= MODE_DISABLED
);
83 if (iface
->dhcpv4_event
.uloop
.fd
>= 0) {
84 uloop_fd_delete(&iface
->dhcpv4_event
.uloop
);
85 close(iface
->dhcpv4_event
.uloop
.fd
);
86 iface
->dhcpv4_event
.uloop
.fd
= -1;
90 struct sockaddr_in bind_addr
= {AF_INET
, htons(DHCPV4_SERVER_PORT
),
94 iface
->dhcpv4_event
.uloop
.fd
= socket(AF_INET
, SOCK_DGRAM
| SOCK_CLOEXEC
, IPPROTO_UDP
);
95 if (iface
->dhcpv4_event
.uloop
.fd
< 0) {
96 syslog(LOG_ERR
, "socket(AF_INET): %m");
101 /* Basic IPv4 configuration */
102 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, SOL_SOCKET
, SO_REUSEADDR
,
103 &val
, sizeof(val
)) < 0) {
104 syslog(LOG_ERR
, "setsockopt(SO_REUSEADDR): %m");
109 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, SOL_SOCKET
, SO_BROADCAST
,
110 &val
, sizeof(val
)) < 0) {
111 syslog(LOG_ERR
, "setsockopt(SO_BROADCAST): %m");
116 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, IPPROTO_IP
, IP_PKTINFO
,
117 &val
, sizeof(val
)) < 0) {
118 syslog(LOG_ERR
, "setsockopt(IP_PKTINFO): %m");
123 val
= IPTOS_PREC_INTERNETCONTROL
;
124 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, IPPROTO_IP
, IP_TOS
,
125 &val
, sizeof(val
)) < 0) {
126 syslog(LOG_ERR
, "setsockopt(IP_TOS): %m");
131 val
= IP_PMTUDISC_DONT
;
132 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, IPPROTO_IP
, IP_MTU_DISCOVER
,
133 &val
, sizeof(val
)) < 0) {
134 syslog(LOG_ERR
, "setsockopt(IP_MTU_DISCOVER): %m");
139 if (setsockopt(iface
->dhcpv4_event
.uloop
.fd
, SOL_SOCKET
, SO_BINDTODEVICE
,
140 iface
->ifname
, strlen(iface
->ifname
)) < 0) {
141 syslog(LOG_ERR
, "setsockopt(SO_BINDTODEVICE): %m");
146 if (bind(iface
->dhcpv4_event
.uloop
.fd
, (struct sockaddr
*)&bind_addr
,
147 sizeof(bind_addr
)) < 0) {
148 syslog(LOG_ERR
, "bind(): %m");
153 if (setup_dhcpv4_addresses(iface
) < 0) {
158 iface
->dhcpv4_event
.handle_dgram
= handle_dhcpv4
;
159 odhcpd_register(&iface
->dhcpv4_event
);
161 while (!list_empty(&iface
->dhcpv4_assignments
))
162 free_assignment(list_first_entry(&iface
->dhcpv4_assignments
,
163 struct dhcp_assignment
, head
));
167 if (ret
< 0 && iface
->dhcpv4_event
.uloop
.fd
>= 0) {
168 close(iface
->dhcpv4_event
.uloop
.fd
);
169 iface
->dhcpv4_event
.uloop
.fd
= -1;
176 static void dhcpv4_netevent_cb(unsigned long event
, struct netevent_handler_info
*info
)
178 struct interface
*iface
= info
->iface
;
180 if (!iface
|| iface
->dhcpv4
== MODE_DISABLED
)
184 case NETEV_IFINDEX_CHANGE
:
185 dhcpv4_setup_interface(iface
, true);
187 case NETEV_ADDRLIST_CHANGE
:
188 handle_addrlist_change(iface
);
195 static struct dhcp_assignment
*find_assignment_by_hwaddr(struct interface
*iface
, const uint8_t *hwaddr
)
197 struct dhcp_assignment
*a
;
199 list_for_each_entry(a
, &iface
->dhcpv4_assignments
, head
)
200 if (!memcmp(a
->hwaddr
, hwaddr
, 6))
206 static int setup_dhcpv4_addresses(struct interface
*iface
)
208 iface
->dhcpv4_start_ip
.s_addr
= INADDR_ANY
;
209 iface
->dhcpv4_end_ip
.s_addr
= INADDR_ANY
;
210 iface
->dhcpv4_local
.s_addr
= INADDR_ANY
;
211 iface
->dhcpv4_bcast
.s_addr
= INADDR_ANY
;
212 iface
->dhcpv4_mask
.s_addr
= INADDR_ANY
;
215 if (iface
->dhcpv4_start
.s_addr
& htonl(0xffff0000) ||
216 iface
->dhcpv4_end
.s_addr
& htonl(0xffff0000) ||
217 ntohl(iface
->dhcpv4_start
.s_addr
) > ntohl(iface
->dhcpv4_end
.s_addr
)) {
218 syslog(LOG_WARNING
, "Invalid DHCP range for %s", iface
->name
);
222 if (!iface
->addr4_len
) {
223 syslog(LOG_WARNING
, "No network(s) available on %s", iface
->name
);
227 uint32_t start
= ntohl(iface
->dhcpv4_start
.s_addr
);
228 uint32_t end
= ntohl(iface
->dhcpv4_end
.s_addr
);
230 for (size_t i
= 0; i
< iface
->addr4_len
&& start
&& end
; i
++) {
231 struct in_addr
*addr
= &iface
->addr4
[i
].addr
.in
;
234 if (addr_is_fr_ip(iface
, addr
))
237 odhcpd_bitlen2netmask(false, iface
->addr4
[i
].prefix
, &mask
);
238 if ((start
& ntohl(~mask
.s_addr
)) == start
&&
239 (end
& ntohl(~mask
.s_addr
)) == end
&&
240 end
< ntohl(~mask
.s_addr
)) { /* Exclude broadcast address */
241 iface
->dhcpv4_start_ip
.s_addr
= htonl(start
) |
242 (addr
->s_addr
& mask
.s_addr
);
243 iface
->dhcpv4_end_ip
.s_addr
= htonl(end
) |
244 (addr
->s_addr
& mask
.s_addr
);
245 iface
->dhcpv4_local
= *addr
;
246 iface
->dhcpv4_bcast
= iface
->addr4
[i
].broadcast
;
247 iface
->dhcpv4_mask
= mask
;
252 /* Don't allocate IP range for subnets smaller than /28 */
253 if (iface
->addr4
[0].prefix
> MAX_PREFIX_LEN
) {
254 syslog(LOG_WARNING
, "Auto allocation of DHCP range fails on %s (prefix length must be < %d).", iface
->name
, MAX_PREFIX_LEN
+ 1);
258 iface
->dhcpv4_local
= iface
->addr4
[0].addr
.in
;
259 iface
->dhcpv4_bcast
= iface
->addr4
[0].broadcast
;
260 odhcpd_bitlen2netmask(false, iface
->addr4
[0].prefix
, &iface
->dhcpv4_mask
);
261 end
= start
= iface
->dhcpv4_local
.s_addr
& iface
->dhcpv4_mask
.s_addr
;
263 /* Auto allocate ranges */
264 if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffff00) { /* /24, 150 of 256, [100..249] */
265 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(100);
266 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(100 + 150 - 1);
267 } else if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffff80) { /* /25, 100 of 128, [20..119] */
268 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(20);
269 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(20 + 100 - 1);
270 } else if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffffc0) { /* /26, 50 of 64, [10..59] */
271 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(10);
272 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(10 + 50 - 1);
273 } else if (ntohl(iface
->dhcpv4_mask
.s_addr
) <= 0xffffffe0) { /* /27, 20 of 32, [10..29] */
274 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(10);
275 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(10 + 20 - 1);
276 } else { /* /28, 10 of 16, [3..12] */
277 iface
->dhcpv4_start_ip
.s_addr
= start
| htonl(3);
278 iface
->dhcpv4_end_ip
.s_addr
= end
| htonl(3 + 10 - 1);
284 static void inc_ref_cnt_ip(struct odhcpd_ref_ip
**ptr
, struct odhcpd_ref_ip
*ip
)
290 static void decr_ref_cnt_ip(struct odhcpd_ref_ip
**ptr
, struct interface
*iface
)
292 struct odhcpd_ref_ip
*ip
= *ptr
;
294 if (--ip
->ref_cnt
== 0) {
295 netlink_setup_addr(&ip
->addr
, iface
->ifindex
, false, false);
304 static bool addr_is_fr_ip(struct interface
*iface
, struct in_addr
*addr
)
306 struct odhcpd_ref_ip
*p
;
308 list_for_each_entry(p
, &iface
->dhcpv4_fr_ips
, head
) {
309 if (addr
->s_addr
== p
->addr
.addr
.in
.s_addr
)
316 static bool leases_require_fr(struct interface
*iface
, struct odhcpd_ipaddr
*addr
,
319 struct dhcp_assignment
*a
= NULL
;
320 struct odhcpd_ref_ip
*fr_ip
= NULL
;
322 list_for_each_entry(a
, &iface
->dhcpv4_assignments
, head
) {
323 if ((a
->accept_fr_nonce
|| iface
->dhcpv4_forcereconf
) &&
325 ((a
->addr
& mask
) == (addr
->addr
.in
.s_addr
& mask
))) {
327 fr_ip
= calloc(1, sizeof(*fr_ip
));
331 list_add(&fr_ip
->head
, &iface
->dhcpv4_fr_ips
);
334 inc_ref_cnt_ip(&a
->fr_ip
, fr_ip
);
338 return fr_ip
? true : false;
341 static void valid_until_cb(struct uloop_timeout
*event
)
343 struct interface
*iface
;
344 time_t now
= odhcpd_time();
346 avl_for_each_element(&interfaces
, iface
, avl
) {
347 struct dhcp_assignment
*a
, *n
;
349 if (iface
->dhcpv4
!= MODE_SERVER
)
352 list_for_each_entry_safe(a
, n
, &iface
->dhcpv4_assignments
, head
) {
353 if (!INFINITE_VALID(a
->valid_until
) && a
->valid_until
< now
)
357 uloop_timeout_set(event
, 1000);
360 static void handle_addrlist_change(struct interface
*iface
)
362 struct odhcpd_ipaddr ip
;
363 struct odhcpd_ref_ip
*a
;
364 struct dhcp_assignment
*c
;
365 uint32_t mask
= iface
->dhcpv4_mask
.s_addr
;
367 memset(&ip
, 0, sizeof(ip
));
368 ip
.addr
.in
= iface
->dhcpv4_local
;
369 ip
.prefix
= odhcpd_netmask2bitlen(false, &iface
->dhcpv4_mask
);
370 ip
.broadcast
= iface
->dhcpv4_bcast
;
372 setup_dhcpv4_addresses(iface
);
374 if ((ip
.addr
.in
.s_addr
& mask
) ==
375 (iface
->dhcpv4_local
.s_addr
& iface
->dhcpv4_mask
.s_addr
))
378 if (ip
.addr
.in
.s_addr
&& !leases_require_fr(iface
, &ip
, mask
))
381 if (iface
->dhcpv4_local
.s_addr
== INADDR_ANY
|| list_empty(&iface
->dhcpv4_fr_ips
))
384 a
= list_first_entry(&iface
->dhcpv4_fr_ips
, struct odhcpd_ref_ip
, head
);
386 if (netlink_setup_addr(&a
->addr
, iface
->ifindex
, false, true)) {
387 syslog(LOG_WARNING
, "Failed to add ip address on %s", iface
->name
);
391 list_for_each_entry(c
, &iface
->dhcpv4_assignments
, head
) {
392 if ((c
->flags
& OAF_BOUND
) && c
->fr_ip
&& !c
->fr_cnt
) {
393 if (c
->accept_fr_nonce
|| iface
->dhcpv4_forcereconf
)
394 dhcpv4_fr_rand_delay(c
);
401 static char *dhcpv4_msg_to_string(uint8_t reqmsg
)
404 case (DHCPV4_MSG_DISCOVER
):
405 return "DHCPV4_MSG_DISCOVER";
406 case (DHCPV4_MSG_OFFER
):
407 return "DHCPV4_MSG_OFFER";
408 case (DHCPV4_MSG_REQUEST
):
409 return "DHCPV4_MSG_REQUEST";
410 case (DHCPV4_MSG_DECLINE
):
411 return "DHCPV4_MSG_DECLINE";
412 case (DHCPV4_MSG_ACK
):
413 return "DHCPV4_MSG_ACK";
414 case (DHCPV4_MSG_NAK
):
415 return "DHCPV4_MSG_NAK";
416 case (DHCPV4_MSG_RELEASE
):
417 return "DHCPV4_MSG_RELEASE";
418 case (DHCPV4_MSG_INFORM
):
419 return "DHCPV4_MSG_INFORM";
420 case (DHCPV4_MSG_FORCERENEW
):
421 return "DHCPV4_MSG_FORCERENEW";
427 static void dhcpv4_free_assignment(struct dhcp_assignment
*a
)
433 static void dhcpv4_put(struct dhcpv4_message
*msg
, uint8_t **cookie
,
434 uint8_t type
, uint8_t len
, const void *data
)
436 uint8_t *c
= *cookie
;
437 uint8_t *end
= (uint8_t *)msg
+ sizeof(*msg
);
438 bool tag_only
= type
== DHCPV4_OPT_PAD
|| type
== DHCPV4_OPT_END
;
439 int total_len
= tag_only
? 1 : 2 + len
;
441 if (*cookie
+ total_len
> end
)
444 *cookie
+= total_len
;
451 memcpy(c
, data
, len
);
454 static void dhcpv4_fr_send(struct dhcp_assignment
*a
)
456 struct dhcpv4_message fr_msg
= {
457 .op
= DHCPV4_BOOTREPLY
,
463 .ciaddr
= {INADDR_ANY
},
464 .yiaddr
= {INADDR_ANY
},
465 .siaddr
= {INADDR_ANY
},
466 .giaddr
= {INADDR_ANY
},
471 struct dhcpv4_auth_forcerenew
*auth_o
, auth
= {
475 .replay
= {htonl(time(NULL
)), htonl(++serial
)},
479 struct interface
*iface
= a
->iface
;
481 odhcpd_urandom(&fr_msg
.xid
, sizeof(fr_msg
.xid
));
482 memcpy(fr_msg
.chaddr
, a
->hwaddr
, fr_msg
.hlen
);
484 fr_msg
.options
[0] = 0x63;
485 fr_msg
.options
[1] = 0x82;
486 fr_msg
.options
[2] = 0x53;
487 fr_msg
.options
[3] = 0x63;
489 uint8_t *cookie
= &fr_msg
.options
[4];
490 uint8_t msg
= DHCPV4_MSG_FORCERENEW
;
492 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_MESSAGE
, 1, &msg
);
493 if (a
->accept_fr_nonce
) {
494 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_AUTHENTICATION
, sizeof(auth
), &auth
);
495 auth_o
= (struct dhcpv4_auth_forcerenew
*)(cookie
- sizeof(auth
));
496 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_END
, 0, NULL
);
499 uint8_t secretbytes
[64];
500 memset(secretbytes
, 0, sizeof(secretbytes
));
501 memcpy(secretbytes
, a
->key
, sizeof(a
->key
));
503 for (size_t i
= 0; i
< sizeof(secretbytes
); ++i
)
504 secretbytes
[i
] ^= 0x36;
507 md5_hash(secretbytes
, sizeof(secretbytes
), &md5
);
508 md5_hash(&fr_msg
, sizeof(fr_msg
), &md5
);
509 md5_end(auth_o
->key
, &md5
);
511 for (size_t i
= 0; i
< sizeof(secretbytes
); ++i
) {
512 secretbytes
[i
] ^= 0x36;
513 secretbytes
[i
] ^= 0x5c;
517 md5_hash(secretbytes
, sizeof(secretbytes
), &md5
);
518 md5_hash(auth_o
->key
, sizeof(auth_o
->key
), &md5
);
519 md5_end(auth_o
->key
, &md5
);
521 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_SERVERID
, 4,
522 &a
->fr_ip
->addr
.addr
.in
.s_addr
);
523 dhcpv4_put(&fr_msg
, &cookie
, DHCPV4_OPT_END
, 0, NULL
);
526 struct sockaddr_in dest
;
527 memset(&dest
, 0, sizeof(dest
));
528 dest
.sin_family
= AF_INET
;
529 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
530 dest
.sin_addr
.s_addr
= a
->addr
;
532 if (sendto(iface
->dhcpv4_event
.uloop
.fd
, &fr_msg
, PACKET_SIZE(&fr_msg
, cookie
),
533 MSG_DONTWAIT
, (struct sockaddr
*)&dest
, sizeof(dest
)) < 0)
534 syslog(LOG_ERR
, "Failed to send %s to %s - %s: %m", dhcpv4_msg_to_string(msg
),
535 odhcpd_print_mac(a
->hwaddr
, sizeof(a
->hwaddr
)), inet_ntoa(dest
.sin_addr
));
537 syslog(LOG_DEBUG
, "Sent %s to %s - %s", dhcpv4_msg_to_string(msg
),
538 odhcpd_print_mac(a
->hwaddr
, sizeof(a
->hwaddr
)), inet_ntoa(dest
.sin_addr
));
541 static void dhcpv4_fr_timer(struct uloop_timeout
*event
)
543 struct dhcp_assignment
*a
= container_of(event
, struct dhcp_assignment
, fr_timer
);
545 if (a
->fr_cnt
> 0 && a
->fr_cnt
< 8) {
547 uloop_timeout_set(&a
->fr_timer
, 1000 << a
->fr_cnt
);
553 static void dhcpv4_fr_start(struct dhcp_assignment
*a
)
555 uloop_timeout_set(&a
->fr_timer
, 1000 << a
->fr_cnt
);
556 a
->fr_timer
.cb
= dhcpv4_fr_timer
;
562 static void dhcpv4_fr_delay_timer(struct uloop_timeout
*event
)
564 struct dhcp_assignment
*a
= container_of(event
, struct dhcp_assignment
, fr_timer
);
565 struct interface
*iface
= a
->iface
;
567 (iface
->dhcpv4_event
.uloop
.fd
== -1 ? dhcpv4_fr_rand_delay(a
) : dhcpv4_fr_start(a
));
570 static void dhcpv4_fr_rand_delay(struct dhcp_assignment
*a
)
572 #define MIN_DELAY 500
576 odhcpd_urandom(&msecs
, sizeof(msecs
));
578 msecs
= labs(msecs
)%MAX_FUZZ
+ MIN_DELAY
;
580 uloop_timeout_set(&a
->fr_timer
, msecs
);
581 a
->fr_timer
.cb
= dhcpv4_fr_delay_timer
;
584 static void dhcpv4_fr_stop(struct dhcp_assignment
*a
)
586 uloop_timeout_cancel(&a
->fr_timer
);
587 decr_ref_cnt_ip(&a
->fr_ip
, a
->iface
);
589 a
->fr_timer
.cb
= NULL
;
592 static int dhcpv4_send_reply(const void *buf
, size_t len
,
593 const struct sockaddr
*dest
, socklen_t dest_len
,
598 return sendto(*sock
, buf
, len
, MSG_DONTWAIT
, dest
, dest_len
);
601 /* Handler for DHCPv4 messages */
602 static void handle_dhcpv4(void *addr
, void *data
, size_t len
,
603 struct interface
*iface
, _unused
void *dest_addr
)
605 int sock
= iface
->dhcpv4_event
.uloop
.fd
;
607 dhcpv4_handle_msg(addr
, data
, len
, iface
, dest_addr
, dhcpv4_send_reply
, &sock
);
610 void dhcpv4_handle_msg(void *addr
, void *data
, size_t len
,
611 struct interface
*iface
, _unused
void *dest_addr
,
612 send_reply_cb_t send_reply
, void *opaque
)
614 struct dhcpv4_message
*req
= data
;
616 if (iface
->dhcpv4
== MODE_DISABLED
)
619 if (len
< offsetof(struct dhcpv4_message
, options
) + 4 ||
620 req
->op
!= DHCPV4_BOOTREQUEST
|| req
->hlen
!= 6)
623 syslog(LOG_DEBUG
, "Got DHCPv4 request on %s", iface
->name
);
625 if (!iface
->dhcpv4_start_ip
.s_addr
&& !iface
->dhcpv4_end_ip
.s_addr
) {
626 syslog(LOG_WARNING
, "No DHCP range available on %s", iface
->name
);
630 int sock
= iface
->dhcpv4_event
.uloop
.fd
;
632 struct dhcpv4_message reply
= {
633 .op
= DHCPV4_BOOTREPLY
,
640 .ciaddr
= {INADDR_ANY
},
641 .giaddr
= req
->giaddr
,
642 .siaddr
= iface
->dhcpv4_local
,
644 memcpy(reply
.chaddr
, req
->chaddr
, sizeof(reply
.chaddr
));
646 reply
.options
[0] = 0x63;
647 reply
.options
[1] = 0x82;
648 reply
.options
[2] = 0x53;
649 reply
.options
[3] = 0x63;
651 uint8_t *cookie
= &reply
.options
[4];
652 uint8_t reqmsg
= DHCPV4_MSG_REQUEST
;
653 uint8_t msg
= DHCPV4_MSG_ACK
;
655 uint32_t reqaddr
= INADDR_ANY
;
656 uint32_t leasetime
= 0;
657 size_t hostname_len
= 0;
658 size_t reqopts_len
= 0;
661 bool accept_fr_nonce
= false;
662 bool incl_fr_opt
= false;
664 uint8_t *start
= &req
->options
[4];
665 uint8_t *end
= ((uint8_t*)data
) + len
;
666 struct dhcpv4_option
*opt
;
667 dhcpv4_for_each_option(start
, end
, opt
) {
668 if (opt
->type
== DHCPV4_OPT_MESSAGE
&& opt
->len
== 1)
669 reqmsg
= opt
->data
[0];
670 else if (opt
->type
== DHCPV4_OPT_REQOPTS
&& opt
->len
> 0) {
671 reqopts_len
= opt
->len
;
672 memcpy(reqopts
, opt
->data
, reqopts_len
);
673 reqopts
[reqopts_len
] = 0;
674 } else if (opt
->type
== DHCPV4_OPT_HOSTNAME
&& opt
->len
> 0) {
675 hostname_len
= opt
->len
;
676 memcpy(hostname
, opt
->data
, hostname_len
);
677 hostname
[hostname_len
] = 0;
678 } else if (opt
->type
== DHCPV4_OPT_IPADDRESS
&& opt
->len
== 4)
679 memcpy(&reqaddr
, opt
->data
, 4);
680 else if (opt
->type
== DHCPV4_OPT_SERVERID
&& opt
->len
== 4) {
681 if (memcmp(opt
->data
, &iface
->dhcpv4_local
, 4))
683 } else if (iface
->filter_class
&& opt
->type
== DHCPV4_OPT_USER_CLASS
) {
684 uint8_t *c
= opt
->data
, *cend
= &opt
->data
[opt
->len
];
685 for (; c
< cend
&& &c
[*c
] < cend
; c
= &c
[1 + *c
]) {
686 size_t elen
= strlen(iface
->filter_class
);
687 if (*c
== elen
&& !memcmp(&c
[1], iface
->filter_class
, elen
))
688 return; // Ignore from homenet
690 } else if (opt
->type
== DHCPV4_OPT_LEASETIME
&& opt
->len
== 4)
691 memcpy(&leasetime
, opt
->data
, 4);
692 else if (opt
->type
== DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE
&& opt
->len
> 0) {
693 for (uint8_t i
= 0; i
< opt
->len
; i
++) {
694 if (opt
->data
[i
] == 1) {
695 accept_fr_nonce
= true;
703 if (reqmsg
!= DHCPV4_MSG_DISCOVER
&& reqmsg
!= DHCPV4_MSG_REQUEST
&&
704 reqmsg
!= DHCPV4_MSG_INFORM
&& reqmsg
!= DHCPV4_MSG_DECLINE
&&
705 reqmsg
!= DHCPV4_MSG_RELEASE
)
708 struct dhcp_assignment
*a
= NULL
;
709 uint32_t serverid
= iface
->dhcpv4_local
.s_addr
;
710 uint32_t fr_serverid
= INADDR_ANY
;
712 if (reqmsg
!= DHCPV4_MSG_INFORM
)
713 a
= dhcpv4_lease(iface
, reqmsg
, req
->chaddr
, reqaddr
,
714 &leasetime
, hostname
, hostname_len
,
715 accept_fr_nonce
, &incl_fr_opt
, &fr_serverid
,
716 reqopts
, reqopts_len
);
719 if (reqmsg
== DHCPV4_MSG_REQUEST
)
720 msg
= DHCPV4_MSG_NAK
;
721 else if (reqmsg
== DHCPV4_MSG_DISCOVER
)
723 } else if (reqmsg
== DHCPV4_MSG_DISCOVER
)
724 msg
= DHCPV4_MSG_OFFER
;
725 else if (reqmsg
== DHCPV4_MSG_REQUEST
&&
726 ((reqaddr
&& reqaddr
!= a
->addr
) ||
727 (req
->ciaddr
.s_addr
&& req
->ciaddr
.s_addr
!= a
->addr
))) {
728 msg
= DHCPV4_MSG_NAK
;
730 * DHCP client requested an IP which we can't offer to him. Probably the
731 * client changed the network or the network has been changed. The reply
732 * type is set to DHCPV4_MSG_NAK, because the client should not use that IP.
734 * For modern devices we build an answer that includes a valid IP, like
735 * a DHCPV4_MSG_ACK. The client will use that IP and doesn't need to
736 * perform additional DHCP round trips.
742 * Buggy clients do serverid checking in nack messages; therefore set the
743 * serverid in nack messages triggered by a previous force renew equal to
744 * the server id in use at that time by the server
748 serverid
= fr_serverid
;
750 if (req
->ciaddr
.s_addr
&&
751 ((iface
->dhcpv4_start_ip
.s_addr
& iface
->dhcpv4_mask
.s_addr
) !=
752 (req
->ciaddr
.s_addr
& iface
->dhcpv4_mask
.s_addr
)))
753 req
->ciaddr
.s_addr
= INADDR_ANY
;
756 syslog(LOG_INFO
, "Received %s from %s on %s", dhcpv4_msg_to_string(reqmsg
),
757 odhcpd_print_mac(req
->chaddr
, req
->hlen
), iface
->name
);
760 if (reqmsg
== DHCPV4_MSG_RELEASE
)
761 ubus_bcast_dhcp_event("dhcp.release", req
->chaddr
, req
->hlen
,
762 &req
->ciaddr
, a
? a
->hostname
: NULL
, iface
->ifname
);
764 if (reqmsg
== DHCPV4_MSG_DECLINE
|| reqmsg
== DHCPV4_MSG_RELEASE
)
767 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_MESSAGE
, 1, &msg
);
768 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_SERVERID
, 4, &serverid
);
773 reply
.yiaddr
.s_addr
= a
->addr
;
775 val
= htonl(leasetime
);
776 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_LEASETIME
, 4, &val
);
778 if (leasetime
!= UINT32_MAX
) {
779 val
= htonl(500 * leasetime
/ 1000);
780 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_RENEW
, 4, &val
);
782 val
= htonl(875 * leasetime
/ 1000);
783 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_REBIND
, 4, &val
);
786 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_NETMASK
, 4,
787 &iface
->dhcpv4_mask
.s_addr
);
790 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_HOSTNAME
,
791 strlen(a
->hostname
), a
->hostname
);
793 if (iface
->dhcpv4_bcast
.s_addr
!= INADDR_ANY
)
794 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_BROADCAST
, 4, &iface
->dhcpv4_bcast
);
797 if (reqmsg
== DHCPV4_MSG_REQUEST
) {
798 struct dhcpv4_auth_forcerenew auth
= {
802 .replay
= {htonl(time(NULL
)), htonl(++serial
)},
807 memcpy(auth
.key
, a
->key
, sizeof(auth
.key
));
808 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_AUTHENTICATION
, sizeof(auth
), &auth
);
811 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE
,
819 memset(&ifr
, 0, sizeof(ifr
));
820 strncpy(ifr
.ifr_name
, iface
->ifname
, sizeof(ifr
.ifr_name
) - 1);
822 if (!ioctl(sock
, SIOCGIFMTU
, &ifr
)) {
823 uint16_t mtu
= htons(ifr
.ifr_mtu
);
824 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_MTU
, 2, &mtu
);
827 if (iface
->search
&& iface
->search_len
<= 255)
828 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_SEARCH_DOMAIN
,
829 iface
->search_len
, iface
->search
);
830 else if (!res_init() && _res
.dnsrch
[0] && _res
.dnsrch
[0][0]) {
831 uint8_t search_buf
[256];
832 int len
= dn_comp(_res
.dnsrch
[0], search_buf
,
833 sizeof(search_buf
), NULL
, NULL
);
835 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_SEARCH_DOMAIN
,
839 if (iface
->dhcpv4_router_cnt
== 0)
840 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_ROUTER
, 4, &iface
->dhcpv4_local
);
842 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_ROUTER
,
843 4 * iface
->dhcpv4_router_cnt
, iface
->dhcpv4_router
);
846 if (iface
->dhcpv4_dns_cnt
== 0) {
847 if (iface
->dns_service
)
848 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_DNSSERVER
, 4, &iface
->dhcpv4_local
);
850 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_DNSSERVER
,
851 4 * iface
->dhcpv4_dns_cnt
, iface
->dhcpv4_dns
);
853 if (a
&& a
->reqopts
&& iface
->dhcpv4_ntp_cnt
!= 0) {
854 for(size_t opts
= 0; a
->reqopts
[opts
]; opts
++) {
855 if (a
->reqopts
[opts
] == DHCPV4_OPT_NTPSERVER
) {
856 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_NTPSERVER
,
857 4 * iface
->dhcpv4_ntp_cnt
, iface
->dhcpv4_ntp
);
862 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_END
, 0, NULL
);
864 struct sockaddr_in dest
= *((struct sockaddr_in
*)addr
);
865 if (req
->giaddr
.s_addr
) {
867 * relay agent is configured, send reply to the agent
869 dest
.sin_addr
= req
->giaddr
;
870 dest
.sin_port
= htons(DHCPV4_SERVER_PORT
);
871 } else if (req
->ciaddr
.s_addr
&& req
->ciaddr
.s_addr
!= dest
.sin_addr
.s_addr
) {
873 * client has existing configuration (ciaddr is set) AND this address is
874 * not the address it used for the dhcp message
876 dest
.sin_addr
= req
->ciaddr
;
877 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
878 } else if ((ntohs(req
->flags
) & DHCPV4_FLAG_BROADCAST
) ||
879 req
->hlen
!= reply
.hlen
|| !reply
.yiaddr
.s_addr
) {
881 * client requests a broadcast reply OR we can't offer an IP
883 dest
.sin_addr
.s_addr
= INADDR_BROADCAST
;
884 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
885 } else if (!req
->ciaddr
.s_addr
&& msg
== DHCPV4_MSG_NAK
) {
887 * client has no previous configuration -> no IP, so we need to reply
888 * with a broadcast packet
890 dest
.sin_addr
.s_addr
= INADDR_BROADCAST
;
891 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
893 struct arpreq arp
= {.arp_flags
= ATF_COM
};
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 if (!(iface
->ifflags
& IFF_NOARP
)) {
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
));
906 if (ioctl(sock
, SIOCSARP
, &arp
) < 0)
907 syslog(LOG_ERR
, "ioctl(SIOCSARP): %m");
911 if (send_reply(&reply
, PACKET_SIZE(&reply
, cookie
),
912 (struct sockaddr
*)&dest
, sizeof(dest
), opaque
) < 0)
913 syslog(LOG_ERR
, "Failed to send %s to %s - %s: %m",
914 dhcpv4_msg_to_string(msg
),
915 dest
.sin_addr
.s_addr
== INADDR_BROADCAST
?
916 "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req
->chaddr
, req
->hlen
),
917 inet_ntoa(dest
.sin_addr
));
919 syslog(LOG_DEBUG
, "Sent %s to %s - %s",
920 dhcpv4_msg_to_string(msg
),
921 dest
.sin_addr
.s_addr
== INADDR_BROADCAST
?
922 "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req
->chaddr
, req
->hlen
),
923 inet_ntoa(dest
.sin_addr
));
927 if (msg
== DHCPV4_MSG_ACK
)
928 ubus_bcast_dhcp_event("dhcp.ack", req
->chaddr
, req
->hlen
, &reply
.yiaddr
,
929 a
? a
->hostname
: NULL
, iface
->ifname
);
933 static bool dhcpv4_insert_assignment(struct list_head
*list
, struct dhcp_assignment
*a
,
936 uint32_t h_addr
= ntohl(addr
);
937 struct dhcp_assignment
*c
;
939 list_for_each_entry(c
, list
, head
) {
940 uint32_t c_addr
= ntohl(c
->addr
);
942 if (c_addr
== h_addr
)
949 /* Insert new node before c (might match list head) */
951 list_add_tail(&a
->head
, &c
->head
);
956 static char* ip4toa(uint32_t addr
)
960 snprintf(buf
, sizeof(buf
), "%u.%u.%u.%u",
961 ((uint8_t *)&addr
)[0], ((uint8_t *)&addr
)[1],
962 ((uint8_t *)&addr
)[2], ((uint8_t *)&addr
)[3]);
967 static bool dhcpv4_assign(struct interface
*iface
, struct dhcp_assignment
*a
,
970 uint32_t start
= ntohl(iface
->dhcpv4_start_ip
.s_addr
);
971 uint32_t end
= ntohl(iface
->dhcpv4_end_ip
.s_addr
);
972 uint32_t count
= end
- start
+ 1;
976 /* Preconfigured IP address by static lease */
978 assigned
= dhcpv4_insert_assignment(&iface
->dhcpv4_assignments
,
982 syslog(LOG_DEBUG
, "Assigning static IP: %s", ip4toa(a
->addr
));
987 /* try to assign the IP the client asked for */
988 if (start
<= ntohl(raddr
) && ntohl(raddr
) <= end
&&
989 !config_find_lease_by_ipaddr(raddr
)) {
990 assigned
= dhcpv4_insert_assignment(&iface
->dhcpv4_assignments
,
994 syslog(LOG_DEBUG
, "Assigning the IP the client asked for: %s",
1001 /* Seed RNG with checksum of hwaddress */
1002 for (size_t i
= 0; i
< sizeof(a
->hwaddr
); ++i
) {
1003 /* Knuth's multiplicative method */
1004 uint8_t o
= a
->hwaddr
[i
];
1005 seed
+= (o
*2654435761) % UINT32_MAX
;
1010 for (uint32_t i
= 0, try = (((uint32_t)rand()) % count
) + start
; i
< count
;
1011 ++i
, try = (((try - start
) + 1) % count
) + start
) {
1012 uint32_t n_try
= htonl(try);
1014 if (config_find_lease_by_ipaddr(n_try
))
1017 assigned
= dhcpv4_insert_assignment(&iface
->dhcpv4_assignments
,
1021 syslog(LOG_DEBUG
, "Assigning mapped IP: %s (try %u of %u)",
1022 ip4toa(a
->addr
), i
+ 1, count
);
1028 syslog(LOG_NOTICE
, "Can't assign any IP address -> address space is full");
1034 static struct dhcp_assignment
*
1035 dhcpv4_lease(struct interface
*iface
, enum dhcpv4_msg msg
, const uint8_t *mac
,
1036 const uint32_t reqaddr
, uint32_t *leasetime
, const char *hostname
,
1037 const size_t hostname_len
, const bool accept_fr_nonce
, bool *incl_fr_opt
,
1038 uint32_t *fr_serverid
, const char* reqopts
, const size_t reqopts_len
)
1040 struct dhcp_assignment
*a
= find_assignment_by_hwaddr(iface
, mac
);
1041 struct lease
*l
= config_find_lease_by_mac(mac
);
1042 time_t now
= odhcpd_time();
1044 if (l
&& a
&& a
->lease
!= l
) {
1049 if (a
&& (a
->flags
& OAF_BOUND
) && a
->fr_ip
) {
1050 *fr_serverid
= a
->fr_ip
->addr
.addr
.in
.s_addr
;
1054 if (msg
== DHCPV4_MSG_DISCOVER
|| msg
== DHCPV4_MSG_REQUEST
) {
1055 bool assigned
= !!a
;
1058 if (!iface
->no_dynamic_dhcp
|| l
) {
1059 /* Create new binding */
1060 a
= alloc_assignment(0);
1062 syslog(LOG_WARNING
, "Failed to alloc assignment on interface %s",
1066 memcpy(a
->hwaddr
, mac
, sizeof(a
->hwaddr
));
1067 /* Set valid time to 0 for static lease indicating */
1068 /* infinite lifetime otherwise current time */
1069 a
->valid_until
= l
? 0 : now
;
1070 a
->dhcp_free_cb
= dhcpv4_free_assignment
;
1072 a
->flags
= OAF_DHCPV4
;
1073 a
->addr
= l
? l
->ipaddr
: INADDR_ANY
;
1075 assigned
= dhcpv4_assign(iface
, a
, reqaddr
);
1078 a
->flags
|= OAF_STATIC
;
1081 a
->hostname
= strdup(l
->hostname
);
1084 a
->leasetime
= l
->leasetime
;
1086 list_add(&a
->lease_list
, &l
->assignments
);
1090 } else if (((a
->addr
& iface
->dhcpv4_mask
.s_addr
) !=
1091 (iface
->dhcpv4_start_ip
.s_addr
& iface
->dhcpv4_mask
.s_addr
)) &&
1092 !(a
->flags
& OAF_STATIC
)) {
1093 list_del_init(&a
->head
);
1094 a
->addr
= INADDR_ANY
;
1096 assigned
= dhcpv4_assign(iface
, a
, reqaddr
);
1100 uint32_t my_leasetime
;
1103 my_leasetime
= a
->leasetime
;
1105 my_leasetime
= iface
->dhcp_leasetime
;
1107 if ((*leasetime
== 0) || (my_leasetime
< *leasetime
))
1108 *leasetime
= my_leasetime
;
1110 if (msg
== DHCPV4_MSG_DISCOVER
) {
1111 a
->flags
&= ~OAF_BOUND
;
1113 *incl_fr_opt
= accept_fr_nonce
;
1114 a
->valid_until
= now
;
1116 if ((!(a
->flags
& OAF_STATIC
) || !a
->hostname
) && hostname_len
> 0) {
1117 a
->hostname
= realloc(a
->hostname
, hostname_len
+ 1);
1119 memcpy(a
->hostname
, hostname
, hostname_len
);
1120 a
->hostname
[hostname_len
] = 0;
1122 if (odhcpd_valid_hostname(a
->hostname
))
1123 a
->flags
&= ~OAF_BROKEN_HOSTNAME
;
1125 a
->flags
|= OAF_BROKEN_HOSTNAME
;
1129 if (reqopts_len
> 0) {
1130 a
->reqopts
= realloc(a
->reqopts
, reqopts_len
+ 1);
1132 memcpy(a
->reqopts
, reqopts
, reqopts_len
);
1133 a
->reqopts
[reqopts_len
] = 0;
1137 if (!(a
->flags
& OAF_BOUND
)) {
1138 a
->accept_fr_nonce
= accept_fr_nonce
;
1139 *incl_fr_opt
= accept_fr_nonce
;
1140 odhcpd_urandom(a
->key
, sizeof(a
->key
));
1141 a
->flags
|= OAF_BOUND
;
1143 *incl_fr_opt
= false;
1145 a
->valid_until
= ((*leasetime
== UINT32_MAX
) ? 0 : (time_t)(now
+ *leasetime
));
1147 } else if (!assigned
&& a
) {
1148 /* Cleanup failed assignment */
1153 } else if (msg
== DHCPV4_MSG_RELEASE
&& a
) {
1154 a
->flags
&= ~OAF_BOUND
;
1155 a
->valid_until
= now
- 1;
1157 } else if (msg
== DHCPV4_MSG_DECLINE
&& a
) {
1158 a
->flags
&= ~OAF_BOUND
;
1160 if (!(a
->flags
& OAF_STATIC
) || a
->lease
->ipaddr
!= a
->addr
) {
1161 memset(a
->hwaddr
, 0, sizeof(a
->hwaddr
));
1162 a
->valid_until
= now
+ 3600; /* Block address for 1h */
1164 a
->valid_until
= now
- 1;
1167 dhcpv6_ia_write_statefile();