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.
20 #include <sys/timerfd.h>
26 static void relay_client_request(struct sockaddr_in6
*source
,
27 const void *data
, size_t len
, struct interface
*iface
);
28 static void relay_server_response(uint8_t *data
, size_t len
);
30 static void handle_dhcpv6(void *addr
, void *data
, size_t len
,
31 struct interface
*iface
);
32 static void handle_client_request(void *addr
, void *data
, size_t len
,
33 struct interface
*iface
);
35 static struct odhcpd_event dhcpv6_event
= {{.fd
= -1}, handle_dhcpv6
};
39 // Create socket and register events
42 int sock
= socket(AF_INET6
, SOCK_DGRAM
| SOCK_CLOEXEC
, IPPROTO_UDP
);
44 // Basic IPv6 configuration
46 setsockopt(sock
, IPPROTO_IPV6
, IPV6_V6ONLY
, &val
, sizeof(val
));
47 setsockopt(sock
, SOL_SOCKET
, SO_REUSEADDR
, &val
, sizeof(val
));
48 setsockopt(sock
, IPPROTO_IPV6
, IPV6_RECVPKTINFO
, &val
, sizeof(val
));
50 val
= DHCPV6_HOP_COUNT_LIMIT
;
51 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
));
54 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_LOOP
, &val
, sizeof(val
));
56 struct sockaddr_in6 bind_addr
= {AF_INET6
, htons(DHCPV6_SERVER_PORT
),
57 0, IN6ADDR_ANY_INIT
, 0};
59 if (bind(sock
, (struct sockaddr
*)&bind_addr
, sizeof(bind_addr
))) {
60 syslog(LOG_ERR
, "Failed to open DHCPv6 server socket: %s",
65 dhcpv6_event
.uloop
.fd
= sock
;
66 odhcpd_register(&dhcpv6_event
);
68 dhcpv6_ia_init(dhcpv6_event
.uloop
.fd
);
74 int setup_dhcpv6_interface(struct interface
*iface
, bool enable
)
76 // Configure multicast settings
77 struct ipv6_mreq relay
= {ALL_DHCPV6_RELAYS
, iface
->ifindex
};
78 struct ipv6_mreq server
= {ALL_DHCPV6_SERVERS
, iface
->ifindex
};
80 setsockopt(dhcpv6_event
.uloop
.fd
, IPPROTO_IPV6
,
81 IPV6_DROP_MEMBERSHIP
, &relay
, sizeof(relay
));
82 setsockopt(dhcpv6_event
.uloop
.fd
, IPPROTO_IPV6
,
83 IPV6_DROP_MEMBERSHIP
, &server
, sizeof(server
));
85 if (enable
&& iface
->dhcpv6
&& !iface
->master
) {
86 setsockopt(dhcpv6_event
.uloop
.fd
, IPPROTO_IPV6
,
87 IPV6_ADD_MEMBERSHIP
, &relay
, sizeof(relay
));
89 if (iface
->dhcpv6
== RELAYD_SERVER
)
90 setsockopt(dhcpv6_event
.uloop
.fd
, IPPROTO_IPV6
,
91 IPV6_ADD_MEMBERSHIP
, &server
, sizeof(server
));
94 setup_dhcpv6_ia_interface(iface
, enable
);
99 static void handle_nested_message(uint8_t *data
, size_t len
,
100 uint8_t **opts
, uint8_t **end
, struct iovec iov
[6])
102 struct dhcpv6_relay_header
*hdr
= (struct dhcpv6_relay_header
*)data
;
103 if (iov
[0].iov_base
== NULL
) {
104 iov
[0].iov_base
= data
;
105 iov
[0].iov_len
= len
;
108 if (len
< sizeof(struct dhcpv6_client_header
))
111 if (hdr
->msg_type
!= DHCPV6_MSG_RELAY_FORW
) {
112 iov
[0].iov_len
= data
- (uint8_t*)iov
[0].iov_base
;
113 struct dhcpv6_client_header
*hdr
= (void*)data
;
114 *opts
= (uint8_t*)&hdr
[1];
119 uint16_t otype
, olen
;
121 dhcpv6_for_each_option(hdr
->options
, data
+ len
, otype
, olen
, odata
) {
122 if (otype
== DHCPV6_OPT_RELAY_MSG
) {
123 iov
[7].iov_base
= odata
+ olen
;
124 iov
[7].iov_len
= (((uint8_t*)iov
[0].iov_base
) + iov
[0].iov_len
)
126 handle_nested_message(odata
, olen
, opts
, end
, iov
);
133 static void update_nested_message(uint8_t *data
, size_t len
, ssize_t pdiff
)
135 struct dhcpv6_relay_header
*hdr
= (struct dhcpv6_relay_header
*)data
;
136 if (hdr
->msg_type
!= DHCPV6_MSG_RELAY_FORW
)
139 hdr
->msg_type
= DHCPV6_MSG_RELAY_REPL
;
141 uint16_t otype
, olen
;
143 dhcpv6_for_each_option(hdr
->options
, data
+ len
, otype
, olen
, odata
) {
144 if (otype
== DHCPV6_OPT_RELAY_MSG
) {
146 odata
[-2] = (olen
>> 8) & 0xff;
147 odata
[-1] = olen
& 0xff;
148 update_nested_message(odata
, olen
- pdiff
, pdiff
);
155 // Simple DHCPv6-server for information requests
156 static void handle_client_request(void *addr
, void *data
, size_t len
,
157 struct interface
*iface
)
159 struct dhcpv6_client_header
*hdr
= data
;
160 if (len
< sizeof(*hdr
))
163 syslog(LOG_NOTICE
, "Got DHCPv6 request");
165 // Construct reply message
166 struct __attribute__((packed
)) {
169 uint16_t serverid_type
;
170 uint16_t serverid_length
;
172 uint16_t hardware_type
;
174 uint16_t clientid_type
;
175 uint16_t clientid_length
;
176 uint8_t clientid_buf
[130];
178 .msg_type
= DHCPV6_MSG_REPLY
,
179 .serverid_type
= htons(DHCPV6_OPT_SERVERID
),
180 .serverid_length
= htons(10),
181 .duid_type
= htons(3),
182 .hardware_type
= htons(1),
183 .clientid_type
= htons(DHCPV6_OPT_CLIENTID
),
186 odhcpd_get_mac(iface
, dest
.mac
);
188 struct __attribute__((packed
)) {
192 } stat
= {htons(DHCPV6_OPT_STATUS
), htons(sizeof(stat
) - 4),
193 htons(DHCPV6_STATUS_NOADDRSAVAIL
)};
195 struct __attribute__((packed
)) {
199 } refresh
= {htons(DHCPV6_OPT_INFO_REFRESH
), htons(sizeof(uint32_t)),
202 struct odhcpd_ipaddr ipaddr
;
203 struct in6_addr
*dns_addr
= iface
->dns
;
204 size_t dns_cnt
= iface
->dns_cnt
;
206 if (dns_cnt
== 0 && odhcpd_get_interface_addresses(iface
->ifindex
, &ipaddr
, 1) == 1) {
207 dns_addr
= &ipaddr
.addr
;
214 } dns
= {htons(DHCPV6_OPT_DNS_SERVERS
), htons(dns_cnt
* sizeof(*dns_addr
))};
218 // DNS Search options
219 uint8_t search_buf
[256], *search_domain
= iface
->search
;
220 size_t search_len
= iface
->search_len
;
222 if (!search_domain
&& !res_init() && _res
.dnsrch
[0] && _res
.dnsrch
[0][0]) {
223 int len
= dn_comp(_res
.dnsrch
[0], search_buf
,
224 sizeof(search_buf
), NULL
, NULL
);
226 search_domain
= search_buf
;
234 } search
= {htons(DHCPV6_OPT_DNS_DOMAIN
), htons(search_len
)};
239 struct iovec iov
[] = {{NULL
, 0},
240 {&dest
, (uint8_t*)&dest
.clientid_type
- (uint8_t*)&dest
},
241 {&dns
, (dns_cnt
) ? sizeof(dns
) : 0},
242 {dns_addr
, dns_cnt
* sizeof(*dns_addr
)},
243 {&search
, (search_len
) ? sizeof(search
) : 0},
244 {search_domain
, search_len
},
248 uint8_t *opts
= (uint8_t*)&hdr
[1], *opts_end
= (uint8_t*)data
+ len
;
249 if (hdr
->msg_type
== DHCPV6_MSG_RELAY_FORW
)
250 handle_nested_message(data
, len
, &opts
, &opts_end
, iov
);
252 memcpy(dest
.tr_id
, &opts
[-3], sizeof(dest
.tr_id
));
254 if (opts
[-4] == DHCPV6_MSG_ADVERTISE
|| opts
[-4] == DHCPV6_MSG_REPLY
|| opts
[-4] == DHCPV6_MSG_RELAY_REPL
)
257 if (opts
[-4] == DHCPV6_MSG_SOLICIT
) {
258 dest
.msg_type
= DHCPV6_MSG_ADVERTISE
;
259 } else if (opts
[-4] == DHCPV6_MSG_INFORMATION_REQUEST
) {
260 iov
[6].iov_base
= &refresh
;
261 iov
[6].iov_len
= sizeof(refresh
);
264 // Go through options and find what we need
265 uint16_t otype
, olen
;
267 dhcpv6_for_each_option(opts
, opts_end
, otype
, olen
, odata
) {
268 if (otype
== DHCPV6_OPT_CLIENTID
&& olen
<= 130) {
269 dest
.clientid_length
= htons(olen
);
270 memcpy(dest
.clientid_buf
, odata
, olen
);
271 iov
[1].iov_len
+= 4 + olen
;
272 } else if (otype
== DHCPV6_OPT_SERVERID
) {
273 if (olen
!= ntohs(dest
.serverid_length
) ||
274 memcmp(odata
, &dest
.duid_type
, olen
))
275 return; // Not for us
279 if (opts
[-4] != DHCPV6_MSG_INFORMATION_REQUEST
) {
280 iov
[6].iov_len
= dhcpv6_handle_ia(pdbuf
, sizeof(pdbuf
), iface
, addr
, &opts
[-4], opts_end
);
281 if (iov
[6].iov_len
== 0 && opts
[-4] == DHCPV6_MSG_REBIND
)
285 if (iov
[0].iov_len
> 0) // Update length
286 update_nested_message(data
, len
, iov
[1].iov_len
+ iov
[2].iov_len
+
287 iov
[3].iov_len
+ iov
[4].iov_len
+ iov
[5].iov_len
+
288 iov
[6].iov_len
- (4 + opts_end
- opts
));
290 odhcpd_send(dhcpv6_event
.uloop
.fd
, addr
, iov
, ARRAY_SIZE(iov
), iface
);
294 // Central DHCPv6-relay handler
295 static void handle_dhcpv6(void *addr
, void *data
, size_t len
,
296 struct interface
*iface
)
298 if (iface
->dhcpv6
== RELAYD_SERVER
) {
299 handle_client_request(addr
, data
, len
, iface
);
300 } else if (iface
->dhcpv6
== RELAYD_RELAY
) {
302 relay_server_response(data
, len
);
304 relay_client_request(addr
, data
, len
, iface
);
309 // Relay server response (regular relay server handling)
310 static void relay_server_response(uint8_t *data
, size_t len
)
312 // Information we need to gather
313 uint8_t *payload_data
= NULL
;
314 size_t payload_len
= 0;
315 int32_t ifaceidx
= 0;
316 struct sockaddr_in6 target
= {AF_INET6
, htons(DHCPV6_CLIENT_PORT
),
317 0, IN6ADDR_ANY_INIT
, 0};
319 syslog(LOG_NOTICE
, "Got a DHCPv6-reply");
322 uint8_t *odata
, *end
= data
+ len
;
324 // Relay DHCPv6 reply from server to client
325 struct dhcpv6_relay_header
*h
= (void*)data
;
326 if (len
< sizeof(*h
) || h
->msg_type
!= DHCPV6_MSG_RELAY_REPL
)
329 memcpy(&target
.sin6_addr
, &h
->peer_address
,
330 sizeof(struct in6_addr
));
332 // Go through options and find what we need
333 dhcpv6_for_each_option(h
->options
, end
, otype
, olen
, odata
) {
334 if (otype
== DHCPV6_OPT_INTERFACE_ID
335 && olen
== sizeof(ifaceidx
)) {
336 memcpy(&ifaceidx
, odata
, sizeof(ifaceidx
));
337 } else if (otype
== DHCPV6_OPT_RELAY_MSG
) {
338 payload_data
= odata
;
343 // Invalid interface-id or basic payload
344 struct interface
*iface
= odhcpd_get_interface_by_index(ifaceidx
);
345 if (!iface
|| iface
->master
|| !payload_data
|| payload_len
< 4)
348 bool is_authenticated
= false;
349 struct in6_addr
*dns_ptr
= NULL
;
350 size_t dns_count
= 0;
352 // If the payload is relay-reply we have to send to the server port
353 if (payload_data
[0] == DHCPV6_MSG_RELAY_REPL
) {
354 target
.sin6_port
= htons(DHCPV6_SERVER_PORT
);
355 } else { // Go through the payload data
356 struct dhcpv6_client_header
*h
= (void*)payload_data
;
357 end
= payload_data
+ payload_len
;
359 dhcpv6_for_each_option(&h
[1], end
, otype
, olen
, odata
) {
360 if (otype
== DHCPV6_OPT_DNS_SERVERS
&& olen
>= 16) {
361 dns_ptr
= (struct in6_addr
*)odata
;
362 dns_count
= olen
/ 16;
363 } else if (otype
== DHCPV6_OPT_AUTH
) {
364 is_authenticated
= true;
369 // Rewrite DNS servers if requested
370 if (iface
->always_rewrite_dns
&& dns_ptr
&& dns_count
> 0) {
371 if (is_authenticated
)
372 return; // Impossible to rewrite
374 struct odhcpd_ipaddr ip
;
375 const struct in6_addr
*rewrite
= iface
->dns
;
376 size_t rewrite_cnt
= iface
->dns_cnt
;
378 if (rewrite_cnt
== 0) {
379 if (odhcpd_get_interface_addresses(iface
->ifindex
, &ip
, 1) < 1)
380 return; // Unable to get interface address
386 // Copy over any other addresses
387 for (size_t i
= 0; i
< dns_count
; ++i
) {
388 size_t j
= (i
< rewrite_cnt
) ? i
: rewrite_cnt
- 1;
389 memcpy(&dns_ptr
[i
], &rewrite
[j
], sizeof(*rewrite
));
393 struct iovec iov
= {payload_data
, payload_len
};
394 odhcpd_send(dhcpv6_event
.uloop
.fd
, &target
, &iov
, 1, iface
);
398 // Relay client request (regular DHCPv6-relay)
399 static void relay_client_request(struct sockaddr_in6
*source
,
400 const void *data
, size_t len
, struct interface
*iface
)
402 struct interface
*master
= odhcpd_get_master_interface();
403 const struct dhcpv6_relay_header
*h
= data
;
404 if (!master
|| master
->dhcpv6
!= RELAYD_RELAY
||
405 h
->msg_type
== DHCPV6_MSG_RELAY_REPL
||
406 h
->msg_type
== DHCPV6_MSG_RECONFIGURE
||
407 h
->msg_type
== DHCPV6_MSG_REPLY
||
408 h
->msg_type
== DHCPV6_MSG_ADVERTISE
)
409 return; // Invalid message types for client
411 syslog(LOG_NOTICE
, "Got a DHCPv6-request");
413 // Construct our forwarding envelope
414 struct dhcpv6_relay_forward_envelope hdr
= {
415 .msg_type
= DHCPV6_MSG_RELAY_FORW
,
417 .interface_id_type
= htons(DHCPV6_OPT_INTERFACE_ID
),
418 .interface_id_len
= htons(sizeof(uint32_t)),
419 .relay_message_type
= htons(DHCPV6_OPT_RELAY_MSG
),
420 .relay_message_len
= htons(len
),
423 if (h
->msg_type
== DHCPV6_MSG_RELAY_FORW
) { // handle relay-forward
424 if (h
->hop_count
>= DHCPV6_HOP_COUNT_LIMIT
)
425 return; // Invalid hop count
427 hdr
.hop_count
= h
->hop_count
+ 1;
430 // use memcpy here as the destination fields are unaligned
431 uint32_t ifindex
= iface
->ifindex
;
432 memcpy(&hdr
.peer_address
, &source
->sin6_addr
, sizeof(struct in6_addr
));
433 memcpy(&hdr
.interface_id_data
, &ifindex
, sizeof(ifindex
));
435 // Detect public IP of slave interface to use as link-address
436 struct odhcpd_ipaddr ip
;
437 if (odhcpd_get_interface_addresses(iface
->ifindex
, &ip
, 1) < 1) {
438 // No suitable address! Is the slave not configured yet?
439 // Detect public IP of master interface and use it instead
440 // This is WRONG and probably violates the RFC. However
441 // otherwise we have a hen and egg problem because the
442 // slave-interface cannot be auto-configured.
443 if (odhcpd_get_interface_addresses(master
->ifindex
, &ip
, 1) < 1)
444 return; // Could not obtain a suitable address
446 memcpy(&hdr
.link_address
, &ip
.addr
, sizeof(hdr
.link_address
));
448 struct sockaddr_in6 dhcpv6_servers
= {AF_INET6
,
449 htons(DHCPV6_SERVER_PORT
), 0, ALL_DHCPV6_SERVERS
, 0};
450 struct iovec iov
[2] = {{&hdr
, sizeof(hdr
)}, {(void*)data
, len
}};
451 odhcpd_send(dhcpv6_event
.uloop
.fd
, &dhcpv6_servers
, iov
, 2, master
);