2 * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License v2 as published by
6 * the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
24 #include <net/if_arp.h>
25 #include <netinet/ip.h>
26 #include <sys/ioctl.h>
27 #include <sys/timerfd.h>
28 #include <arpa/inet.h>
35 static void handle_dhcpv4(void *addr
, void *data
, size_t len
,
36 struct interface
*iface
);
37 static struct dhcpv4_assignment
* dhcpv4_lease(struct interface
*iface
,
38 enum dhcpv4_msg msg
, const uint8_t *mac
, struct in_addr reqaddr
,
39 const char *hostname
);
42 // Create socket and register events
49 int setup_dhcpv4_interface(struct interface
*iface
, bool enable
)
51 if (iface
->dhcpv4_event
.uloop
.fd
> 0) {
52 close(iface
->dhcpv4_event
.uloop
.fd
);
53 iface
->dhcpv4_event
.uloop
.fd
= -1;
56 if (iface
->dhcpv4
&& enable
) {
57 if (!iface
->dhcpv4_assignments
.next
)
58 INIT_LIST_HEAD(&iface
->dhcpv4_assignments
);
60 int sock
= socket(AF_INET
, SOCK_DGRAM
| SOCK_CLOEXEC
, IPPROTO_UDP
);
62 // Basic IPv6 configuration
64 setsockopt(sock
, SOL_SOCKET
, SO_REUSEADDR
, &val
, sizeof(val
));
65 setsockopt(sock
, SOL_SOCKET
, SO_BROADCAST
, &val
, sizeof(val
));
66 setsockopt(sock
, IPPROTO_IP
, IP_PKTINFO
, &val
, sizeof(val
));
68 val
= IPTOS_PREC_INTERNETCONTROL
;
69 setsockopt(sock
, IPPROTO_IP
, IP_TOS
, &val
, sizeof(val
));
71 val
= IP_PMTUDISC_DONT
;
72 setsockopt(sock
, IPPROTO_IP
, IP_MTU_DISCOVER
, &val
, sizeof(val
));
74 setsockopt(sock
, SOL_SOCKET
, SO_BINDTODEVICE
,
75 iface
->ifname
, strlen(iface
->ifname
));
77 struct sockaddr_in bind_addr
= {AF_INET
, htons(DHCPV4_SERVER_PORT
),
80 if (bind(sock
, (struct sockaddr
*)&bind_addr
, sizeof(bind_addr
))) {
81 syslog(LOG_ERR
, "Failed to open DHCPv4 server socket: %s",
87 if (ntohl(iface
->dhcpv4_start
.s_addr
) > ntohl(iface
->dhcpv4_end
.s_addr
)) {
88 syslog(LOG_ERR
, "Invalid DHCP range");
92 // Create a range if not specified
94 strncpy(ifreq
.ifr_name
, iface
->ifname
, sizeof(ifreq
.ifr_name
));
96 struct sockaddr_in
*saddr
= (struct sockaddr_in
*)&ifreq
.ifr_addr
;
97 struct sockaddr_in
*smask
= (struct sockaddr_in
*)&ifreq
.ifr_netmask
;
98 if (!(iface
->dhcpv4_start
.s_addr
& htonl(0xffff0000)) &&
99 !(iface
->dhcpv4_end
.s_addr
& htonl(0xffff0000)) &&
100 !ioctl(sock
, SIOCGIFADDR
, &ifreq
)) {
101 struct in_addr addr
= saddr
->sin_addr
;
103 ioctl(sock
, SIOCGIFNETMASK
, &ifreq
);
104 struct in_addr mask
= smask
->sin_addr
;
106 uint32_t start
= ntohl(iface
->dhcpv4_start
.s_addr
);
107 uint32_t end
= ntohl(iface
->dhcpv4_end
.s_addr
);
109 if (start
&& end
&& start
< end
&&
110 start
> ntohl(addr
.s_addr
& ~mask
.s_addr
) &&
111 (start
& ntohl(mask
.s_addr
)) == start
&&
112 (end
& ntohl(mask
.s_addr
)) == end
) {
113 iface
->dhcpv4_start
.s_addr
= htonl(start
) |
114 (addr
.s_addr
& mask
.s_addr
);
115 iface
->dhcpv4_end
.s_addr
= htonl(end
) |
116 (addr
.s_addr
& mask
.s_addr
);
117 } else if (ntohl(mask
.s_addr
) <= 0xffffffc0) {
118 start
= addr
.s_addr
& mask
.s_addr
;
119 end
= addr
.s_addr
& mask
.s_addr
;
121 if (ntohl(mask
.s_addr
) <= 0xffffff00) {
122 iface
->dhcpv4_start
.s_addr
= start
| htonl(100);
123 iface
->dhcpv4_end
.s_addr
= end
| htonl(250);
125 iface
->dhcpv4_start
.s_addr
= start
| htonl(10);
126 iface
->dhcpv4_end
.s_addr
= end
| htonl(59);
133 // Parse static entries
135 list_for_each_entry(lease
, &leases
, head
) {
137 size_t hostlen
= strlen(lease
->hostname
) + 1;
138 struct dhcpv4_assignment
*a
= calloc(1, sizeof(*a
) + hostlen
);
140 a
->addr
= ntohl(lease
->ipaddr
.s_addr
);
141 memcpy(a
->hwaddr
, lease
->mac
.ether_addr_octet
, sizeof(a
->hwaddr
));
142 memcpy(a
->hostname
, lease
->hostname
, hostlen
);
144 // Assign to all interfaces
145 struct dhcpv4_assignment
*c
;
146 list_for_each_entry(c
, &iface
->dhcpv4_assignments
, head
) {
147 if (c
->addr
> a
->addr
) {
148 list_add_tail(&a
->head
, &c
->head
);
149 } else if (c
->addr
== a
->addr
) {
150 // Already an assignment with that number
159 // Clean invalid assignments
160 struct dhcpv4_assignment
*a
, *n
;
161 list_for_each_entry_safe(a
, n
, &iface
->dhcpv4_assignments
, head
) {
162 if ((htonl(a
->addr
) & smask
->sin_addr
.s_addr
) !=
163 (saddr
->sin_addr
.s_addr
& smask
->sin_addr
.s_addr
)) {
170 if (iface
->dhcpv4_leasetime
< 60)
171 iface
->dhcpv4_leasetime
= 43200;
173 iface
->dhcpv4_event
.uloop
.fd
= sock
;
174 iface
->dhcpv4_event
.handle_dgram
= handle_dhcpv4
;
175 odhcpd_register(&iface
->dhcpv4_event
);
176 } else if (iface
->dhcpv4_assignments
.next
) {
177 while (!list_empty(&iface
->dhcpv4_assignments
)) {
178 struct dhcpv4_assignment
*a
= list_first_entry(&iface
->dhcpv4_assignments
,
179 struct dhcpv4_assignment
, head
);
190 static void dhcpv4_put(struct dhcpv4_message
*msg
, uint8_t **cookie
,
191 uint8_t type
, uint8_t len
, const void *data
)
193 uint8_t *c
= *cookie
;
194 if (*cookie
+ 2 + len
> (uint8_t*)&msg
[1])
199 memcpy(c
, data
, len
);
205 // Simple DHCPv6-server for information requests
206 static void handle_dhcpv4(void *addr
, void *data
, size_t len
,
207 struct interface
*iface
)
212 struct dhcpv4_message
*req
= data
;
213 if (len
< offsetof(struct dhcpv4_message
, options
) + 4 ||
214 req
->op
!= DHCPV4_BOOTREQUEST
|| req
->hlen
!= 6)
217 int sock
= iface
->dhcpv4_event
.uloop
.fd
;
218 struct sockaddr_in ifaddr
;
219 struct sockaddr_in ifnetmask
;
221 syslog(LOG_NOTICE
, "Got DHCPv4 request");
224 memcpy(ifreq
.ifr_name
, iface
->ifname
, sizeof(ifreq
.ifr_name
));
225 if (ioctl(sock
, SIOCGIFADDR
, &ifreq
)) {
226 syslog(LOG_WARNING
, "DHCPv4 failed to detect address: %s", strerror(errno
));
230 memcpy(&ifaddr
, &ifreq
.ifr_addr
, sizeof(ifaddr
));
231 if (ioctl(sock
, SIOCGIFNETMASK
, &ifreq
))
234 memcpy(&ifnetmask
, &ifreq
.ifr_netmask
, sizeof(ifnetmask
));
235 uint32_t network
= ifaddr
.sin_addr
.s_addr
& ifnetmask
.sin_addr
.s_addr
;
237 if ((iface
->dhcpv4_start
.s_addr
& ifnetmask
.sin_addr
.s_addr
) != network
||
238 (iface
->dhcpv4_end
.s_addr
& ifnetmask
.sin_addr
.s_addr
) != network
) {
239 syslog(LOG_WARNING
, "DHCPv4 range out of assigned network");
243 struct ifreq ifr
= {.ifr_name
= ""};
244 strncpy(ifr
.ifr_name
, iface
->ifname
, sizeof(ifr
.ifr_name
));
246 struct dhcpv4_message reply
= {
247 .op
= DHCPV4_BOOTREPLY
,
254 .ciaddr
= {INADDR_ANY
},
255 .giaddr
= req
->giaddr
,
256 .siaddr
= ifaddr
.sin_addr
,
258 memcpy(reply
.chaddr
, req
->chaddr
, sizeof(reply
.chaddr
));
260 reply
.options
[0] = 0x63;
261 reply
.options
[1] = 0x82;
262 reply
.options
[2] = 0x53;
263 reply
.options
[3] = 0x63;
265 uint8_t *cookie
= &reply
.options
[4];
266 uint8_t reqmsg
= DHCPV4_MSG_REQUEST
;
267 uint8_t msg
= DHCPV4_MSG_ACK
;
269 struct in_addr reqaddr
= {INADDR_ANY
};
273 uint8_t *start
= &req
->options
[4];
274 uint8_t *end
= ((uint8_t*)data
) + len
;
275 struct dhcpv4_option
*opt
;
276 dhcpv4_for_each_option(start
, end
, opt
) {
277 if (opt
->type
== DHCPV4_OPT_MESSAGE
&& opt
->len
== 1) {
278 reqmsg
= opt
->data
[0];
279 } else if (opt
->type
== DHCPV4_OPT_HOSTNAME
&& opt
->len
> 0) {
280 memcpy(hostname
, opt
->data
, opt
->len
);
281 hostname
[opt
->len
] = 0;
282 } else if (opt
->type
== DHCPV4_OPT_IPADDRESS
&& opt
->len
== 4) {
283 memcpy(&reqaddr
, opt
->data
, 4);
284 } else if (opt
->type
== DHCPV4_OPT_SERVERID
&& opt
->len
== 4) {
285 if (memcmp(opt
->data
, &ifaddr
.sin_addr
, 4))
290 if (reqmsg
!= DHCPV4_MSG_DISCOVER
&& reqmsg
!= DHCPV4_MSG_REQUEST
&&
291 reqmsg
!= DHCPV4_MSG_INFORM
&& reqmsg
!= DHCPV4_MSG_DECLINE
&&
292 reqmsg
!= DHCPV4_MSG_RELEASE
)
295 struct dhcpv4_assignment
*lease
= NULL
;
296 if (reqmsg
!= DHCPV4_MSG_INFORM
)
297 lease
= dhcpv4_lease(iface
, reqmsg
, req
->chaddr
, reqaddr
, hostname
);
300 if (reqmsg
== DHCPV4_MSG_REQUEST
)
301 msg
= DHCPV4_MSG_NAK
;
302 else if (reqmsg
== DHCPV4_MSG_DISCOVER
)
304 } else if (reqmsg
== DHCPV4_MSG_DISCOVER
) {
305 msg
= DHCPV4_MSG_OFFER
;
308 if (reqmsg
== DHCPV4_MSG_DECLINE
|| reqmsg
== DHCPV4_MSG_RELEASE
)
311 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_MESSAGE
, 1, &msg
);
312 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_SERVERID
, 4, &ifaddr
.sin_addr
);
315 reply
.yiaddr
.s_addr
= htonl(lease
->addr
);
317 uint32_t val
= htonl(iface
->dhcpv4_leasetime
);
318 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_LEASETIME
, 4, &val
);
320 val
= htonl(500 * iface
->dhcpv4_leasetime
/ 1000);
321 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_RENEW
, 4, &val
);
323 val
= htonl(875 * iface
->dhcpv4_leasetime
/ 1000);
324 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_REBIND
, 4, &val
);
326 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_NETMASK
, 4, &ifnetmask
.sin_addr
);
328 if (lease
->hostname
[0])
329 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_HOSTNAME
,
330 strlen(lease
->hostname
), lease
->hostname
);
332 if (!ioctl(sock
, SIOCGIFBRDADDR
, &ifr
)) {
333 struct sockaddr_in
*ina
= (struct sockaddr_in
*)&ifr
.ifr_broadaddr
;
334 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_BROADCAST
, 4, &ina
->sin_addr
);
338 if (!ioctl(sock
, SIOCGIFMTU
, &ifr
)) {
339 uint16_t mtu
= htons(ifr
.ifr_mtu
);
340 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_MTU
, 2, &mtu
);
345 if (dn_expand(iface
->search
, iface
->search
+ iface
->search_len
,
346 iface
->search
, b
, sizeof(b
)) > 0)
347 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_DOMAIN
, strlen(b
), b
);
348 } else if (!res_init() && _res
.dnsrch
[0] && _res
.dnsrch
[0][0]) {
349 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_DOMAIN
,
350 strlen(_res
.dnsrch
[0]), _res
.dnsrch
[0]);
353 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_ROUTER
, 4, &ifaddr
.sin_addr
);
357 if (iface
->dhcpv4_dns_cnt
== 0)
358 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_DNSSERVER
, 4, &ifaddr
.sin_addr
);
360 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_DNSSERVER
,
361 4 * iface
->dhcpv4_dns_cnt
, iface
->dhcpv4_dns
);
364 dhcpv4_put(&reply
, &cookie
, DHCPV4_OPT_END
, 0, NULL
);
366 struct sockaddr_in dest
= *((struct sockaddr_in
*)addr
);
367 if (req
->giaddr
.s_addr
) {
368 dest
.sin_addr
= req
->giaddr
;
369 dest
.sin_port
= htons(DHCPV4_SERVER_PORT
);
370 } else if (req
->ciaddr
.s_addr
&& req
->ciaddr
.s_addr
!= dest
.sin_addr
.s_addr
) {
371 dest
.sin_addr
= req
->ciaddr
;
372 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
373 } else if ((ntohs(req
->flags
) & DHCPV4_FLAG_BROADCAST
) ||
374 req
->hlen
!= reply
.hlen
) {
375 dest
.sin_addr
.s_addr
= INADDR_BROADCAST
;
376 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
378 dest
.sin_addr
= reply
.yiaddr
;
379 dest
.sin_port
= htons(DHCPV4_CLIENT_PORT
);
381 struct arpreq arp
= {.arp_flags
= ATF_COM
};
382 memcpy(arp
.arp_ha
.sa_data
, req
->chaddr
, 6);
383 memcpy(&arp
.arp_pa
, &dest
, sizeof(arp
.arp_pa
));
384 memcpy(arp
.arp_dev
, iface
->ifname
, sizeof(arp
.arp_dev
));
385 ioctl(sock
, SIOCSARP
, &arp
);
388 sendto(sock
, &reply
, sizeof(reply
), MSG_DONTWAIT
,
389 (struct sockaddr
*)&dest
, sizeof(dest
));
393 static bool dhcpv4_assign(struct interface
*iface
,
394 struct dhcpv4_assignment
*assign
, uint32_t raddr
)
396 const unsigned tries
= 10;
397 uint32_t start
= ntohl(iface
->dhcpv4_start
.s_addr
);
398 uint32_t end
= ntohl(iface
->dhcpv4_end
.s_addr
);
399 uint32_t count
= end
- start
+ 1;
401 // Seed RNG with checksum of DUID
403 for (size_t i
= 0; i
< sizeof(assign
->hwaddr
); ++i
)
404 seed
+= assign
->hwaddr
[i
];
407 // Try to assign up to 100x
408 for (unsigned i
= 0; i
< tries
; ++i
) {
409 uint32_t try = (((uint32_t)rand()) % count
) + start
;
410 if (i
== 0 && raddr
>= start
&& raddr
<= end
)
412 else if (i
== tries
- 1)
415 if (list_empty(&iface
->dhcpv4_assignments
)) {
417 list_add(&assign
->head
, &iface
->dhcpv4_assignments
);
421 struct dhcpv4_assignment
*c
;
422 list_for_each_entry(c
, &iface
->dhcpv4_assignments
, head
) {
425 list_add_tail(&assign
->head
, &c
->head
);
427 } else if (c
->addr
== try) {
440 static struct dhcpv4_assignment
* dhcpv4_lease(struct interface
*iface
,
441 enum dhcpv4_msg msg
, const uint8_t *mac
, struct in_addr reqaddr
,
442 const char *hostname
)
444 struct dhcpv4_assignment
*lease
= NULL
;
445 uint32_t raddr
= ntohl(reqaddr
.s_addr
);
446 time_t now
= odhcpd_time();
448 struct dhcpv4_assignment
*c
, *n
, *a
= NULL
;
449 list_for_each_entry_safe(c
, n
, &iface
->dhcpv4_assignments
, head
) {
450 if (c
->addr
== raddr
&& !memcmp(c
->hwaddr
, mac
, 6)) {
453 } else if (c
->valid_until
< now
) {
459 bool update_state
= false;
460 if (msg
== DHCPV4_MSG_DISCOVER
|| msg
== DHCPV4_MSG_REQUEST
) {
462 size_t hostlen
= strlen(hostname
) + 1;
464 if (!a
&& !iface
->no_dynamic_dhcp
) { // Create new binding
465 a
= calloc(1, sizeof(*a
) + hostlen
);
466 memcpy(a
->hwaddr
, mac
, sizeof(a
->hwaddr
));
467 memcpy(a
->hostname
, hostname
, hostlen
);
469 assigned
= dhcpv4_assign(iface
, a
, raddr
);
472 if (assigned
&& !a
->hostname
[0] && hostname
) {
473 a
= realloc(a
, sizeof(*a
) + hostlen
);
474 memcpy(a
->hostname
, hostname
, hostlen
);
477 a
->head
.next
->prev
= &a
->head
;
478 a
->head
.prev
->next
= &a
->head
;
481 // Was only a solicitation: mark binding for removal
482 if (assigned
&& a
->valid_until
< now
) {
483 a
->valid_until
= (msg
== DHCPV4_MSG_DISCOVER
) ? 0 :
484 (now
+ iface
->dhcpv4_leasetime
);
485 } else if (!assigned
&& a
) { // Cleanup failed assignment
492 } else if (msg
== DHCPV4_MSG_RELEASE
) {
497 } else if (msg
== DHCPV4_MSG_DECLINE
) {
498 memset(a
->hwaddr
, 0, sizeof(a
->hwaddr
));
499 a
->valid_until
= now
+ 3600; // Block address for 1h
504 dhcpv6_write_statefile();