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>
25 static const char *excluded_class
= "HOMENET";
28 static void relay_client_request(struct sockaddr_in6
*source
,
29 const void *data
, size_t len
, struct interface
*iface
);
30 static void relay_server_response(uint8_t *data
, size_t len
);
32 static void handle_dhcpv6(void *addr
, void *data
, size_t len
,
33 struct interface
*iface
);
34 static void handle_client_request(void *addr
, void *data
, size_t len
,
35 struct interface
*iface
);
39 // Create socket and register events
47 int setup_dhcpv6_interface(struct interface
*iface
, bool enable
)
49 if (iface
->dhcpv6_event
.uloop
.fd
> 0) {
50 uloop_fd_delete(&iface
->dhcpv6_event
.uloop
);
51 close(iface
->dhcpv6_event
.uloop
.fd
);
52 iface
->dhcpv6_event
.uloop
.fd
= -1;
55 // Configure multicast settings
56 if (enable
&& iface
->dhcpv6
&& !iface
->master
) {
57 int sock
= socket(AF_INET6
, SOCK_DGRAM
| SOCK_CLOEXEC
, IPPROTO_UDP
);
59 syslog(LOG_ERR
, "Failed to create DHCPv6 server socket: %s",
64 // Basic IPv6 configuration
65 setsockopt(sock
, SOL_SOCKET
, SO_BINDTODEVICE
, iface
->ifname
, strlen(iface
->ifname
));
68 setsockopt(sock
, IPPROTO_IPV6
, IPV6_V6ONLY
, &val
, sizeof(val
));
69 setsockopt(sock
, SOL_SOCKET
, SO_REUSEADDR
, &val
, sizeof(val
));
70 setsockopt(sock
, IPPROTO_IPV6
, IPV6_RECVPKTINFO
, &val
, sizeof(val
));
72 val
= DHCPV6_HOP_COUNT_LIMIT
;
73 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
));
76 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_LOOP
, &val
, sizeof(val
));
78 struct sockaddr_in6 bind_addr
= {AF_INET6
, htons(DHCPV6_SERVER_PORT
),
79 0, IN6ADDR_ANY_INIT
, 0};
81 if (bind(sock
, (struct sockaddr
*)&bind_addr
, sizeof(bind_addr
))) {
82 syslog(LOG_ERR
, "Failed to open DHCPv6 server socket: %s",
87 struct ipv6_mreq relay
= {ALL_DHCPV6_RELAYS
, iface
->ifindex
};
88 struct ipv6_mreq server
= {ALL_DHCPV6_SERVERS
, iface
->ifindex
};
89 setsockopt(sock
, IPPROTO_IPV6
, IPV6_ADD_MEMBERSHIP
, &relay
, sizeof(relay
));
91 if (iface
->dhcpv6
== RELAYD_SERVER
)
92 setsockopt(sock
, IPPROTO_IPV6
, IPV6_ADD_MEMBERSHIP
, &server
, sizeof(server
));
94 iface
->dhcpv6_event
.uloop
.fd
= sock
;
95 iface
->dhcpv6_event
.handle_dgram
= handle_dhcpv6
;
96 odhcpd_register(&iface
->dhcpv6_event
);
99 return setup_dhcpv6_ia_interface(iface
, enable
);
103 static void handle_nested_message(uint8_t *data
, size_t len
,
104 uint8_t **opts
, uint8_t **end
, struct iovec iov
[6])
106 struct dhcpv6_relay_header
*hdr
= (struct dhcpv6_relay_header
*)data
;
107 if (iov
[0].iov_base
== NULL
) {
108 iov
[0].iov_base
= data
;
109 iov
[0].iov_len
= len
;
112 if (len
< sizeof(struct dhcpv6_client_header
))
115 if (hdr
->msg_type
!= DHCPV6_MSG_RELAY_FORW
) {
116 iov
[0].iov_len
= data
- (uint8_t*)iov
[0].iov_base
;
117 struct dhcpv6_client_header
*hdr
= (void*)data
;
118 *opts
= (uint8_t*)&hdr
[1];
123 uint16_t otype
, olen
;
125 dhcpv6_for_each_option(hdr
->options
, data
+ len
, otype
, olen
, odata
) {
126 if (otype
== DHCPV6_OPT_RELAY_MSG
) {
127 iov
[7].iov_base
= odata
+ olen
;
128 iov
[7].iov_len
= (((uint8_t*)iov
[0].iov_base
) + iov
[0].iov_len
)
130 handle_nested_message(odata
, olen
, opts
, end
, iov
);
137 static void update_nested_message(uint8_t *data
, size_t len
, ssize_t pdiff
)
139 struct dhcpv6_relay_header
*hdr
= (struct dhcpv6_relay_header
*)data
;
140 if (hdr
->msg_type
!= DHCPV6_MSG_RELAY_FORW
)
143 hdr
->msg_type
= DHCPV6_MSG_RELAY_REPL
;
145 uint16_t otype
, olen
;
147 dhcpv6_for_each_option(hdr
->options
, data
+ len
, otype
, olen
, odata
) {
148 if (otype
== DHCPV6_OPT_RELAY_MSG
) {
150 odata
[-2] = (olen
>> 8) & 0xff;
151 odata
[-1] = olen
& 0xff;
152 update_nested_message(odata
, olen
- pdiff
, pdiff
);
159 // Simple DHCPv6-server for information requests
160 static void handle_client_request(void *addr
, void *data
, size_t len
,
161 struct interface
*iface
)
163 struct dhcpv6_client_header
*hdr
= data
;
164 if (len
< sizeof(*hdr
))
167 syslog(LOG_NOTICE
, "Got DHCPv6 request");
169 // Construct reply message
170 struct __attribute__((packed
)) {
173 uint16_t serverid_type
;
174 uint16_t serverid_length
;
176 uint16_t hardware_type
;
178 uint16_t clientid_type
;
179 uint16_t clientid_length
;
180 uint8_t clientid_buf
[130];
182 .msg_type
= DHCPV6_MSG_REPLY
,
183 .serverid_type
= htons(DHCPV6_OPT_SERVERID
),
184 .serverid_length
= htons(10),
185 .duid_type
= htons(3),
186 .hardware_type
= htons(1),
187 .clientid_type
= htons(DHCPV6_OPT_CLIENTID
),
190 odhcpd_get_mac(iface
, dest
.mac
);
192 struct __attribute__((packed
)) {
196 } stat
= {htons(DHCPV6_OPT_STATUS
), htons(sizeof(stat
) - 4),
197 htons(DHCPV6_STATUS_NOADDRSAVAIL
)};
199 struct __attribute__((packed
)) {
203 } refresh
= {htons(DHCPV6_OPT_INFO_REFRESH
), htons(sizeof(uint32_t)),
206 struct odhcpd_ipaddr ipaddr
;
207 struct in6_addr
*dns_addr
= iface
->dns
;
208 size_t dns_cnt
= iface
->dns_cnt
;
210 if (dns_cnt
== 0 && odhcpd_get_interface_addresses(iface
->ifindex
, &ipaddr
, 1) == 1) {
211 dns_addr
= &ipaddr
.addr
;
218 } dns
= {htons(DHCPV6_OPT_DNS_SERVERS
), htons(dns_cnt
* sizeof(*dns_addr
))};
222 // DNS Search options
223 uint8_t search_buf
[256], *search_domain
= iface
->search
;
224 size_t search_len
= iface
->search_len
;
226 if (!search_domain
&& !res_init() && _res
.dnsrch
[0] && _res
.dnsrch
[0][0]) {
227 int len
= dn_comp(_res
.dnsrch
[0], search_buf
,
228 sizeof(search_buf
), NULL
, NULL
);
230 search_domain
= search_buf
;
238 } search
= {htons(DHCPV6_OPT_DNS_DOMAIN
), htons(search_len
)};
243 struct iovec iov
[] = {{NULL
, 0},
244 {&dest
, (uint8_t*)&dest
.clientid_type
- (uint8_t*)&dest
},
245 {&dns
, (dns_cnt
) ? sizeof(dns
) : 0},
246 {dns_addr
, dns_cnt
* sizeof(*dns_addr
)},
247 {&search
, (search_len
) ? sizeof(search
) : 0},
248 {search_domain
, search_len
},
252 uint8_t *opts
= (uint8_t*)&hdr
[1], *opts_end
= (uint8_t*)data
+ len
;
253 if (hdr
->msg_type
== DHCPV6_MSG_RELAY_FORW
)
254 handle_nested_message(data
, len
, &opts
, &opts_end
, iov
);
256 memcpy(dest
.tr_id
, &opts
[-3], sizeof(dest
.tr_id
));
258 if (opts
[-4] == DHCPV6_MSG_ADVERTISE
|| opts
[-4] == DHCPV6_MSG_REPLY
|| opts
[-4] == DHCPV6_MSG_RELAY_REPL
)
261 if (opts
[-4] == DHCPV6_MSG_SOLICIT
) {
262 dest
.msg_type
= DHCPV6_MSG_ADVERTISE
;
263 } else if (opts
[-4] == DHCPV6_MSG_INFORMATION_REQUEST
) {
264 iov
[6].iov_base
= &refresh
;
265 iov
[6].iov_len
= sizeof(refresh
);
268 // Go through options and find what we need
269 uint16_t otype
, olen
;
271 dhcpv6_for_each_option(opts
, opts_end
, otype
, olen
, odata
) {
272 if (otype
== DHCPV6_OPT_CLIENTID
&& olen
<= 130) {
273 dest
.clientid_length
= htons(olen
);
274 memcpy(dest
.clientid_buf
, odata
, olen
);
275 iov
[1].iov_len
+= 4 + olen
;
276 } else if (otype
== DHCPV6_OPT_SERVERID
) {
277 if (olen
!= ntohs(dest
.serverid_length
) ||
278 memcmp(odata
, &dest
.duid_type
, olen
))
279 return; // Not for us
280 } else if (otype
== DHCPV6_OPT_USER_CLASS
) {
281 uint8_t *c
= odata
, *cend
= &odata
[olen
];
282 for (; &c
[2] <= cend
&& &c
[2 + (c
[0] << 8) + c
[1]] <= cend
; c
= &c
[2 + (c
[0] << 8) + c
[1]]) {
283 size_t elen
= strlen(excluded_class
);
284 if (((((size_t)c
[0]) << 8) | c
[1]) == elen
&& !memcmp(&c
[2], excluded_class
, elen
))
285 return; // Ignore from homenet
290 if (opts
[-4] != DHCPV6_MSG_INFORMATION_REQUEST
) {
291 iov
[6].iov_len
= dhcpv6_handle_ia(pdbuf
, sizeof(pdbuf
), iface
, addr
, &opts
[-4], opts_end
);
292 if (iov
[6].iov_len
== 0 && opts
[-4] == DHCPV6_MSG_REBIND
)
296 if (iov
[0].iov_len
> 0) // Update length
297 update_nested_message(data
, len
, iov
[1].iov_len
+ iov
[2].iov_len
+
298 iov
[3].iov_len
+ iov
[4].iov_len
+ iov
[5].iov_len
+
299 iov
[6].iov_len
- (4 + opts_end
- opts
));
301 odhcpd_send(iface
->dhcpv6_event
.uloop
.fd
, addr
, iov
, ARRAY_SIZE(iov
), iface
);
305 // Central DHCPv6-relay handler
306 static void handle_dhcpv6(void *addr
, void *data
, size_t len
,
307 struct interface
*iface
)
309 if (iface
->dhcpv6
== RELAYD_SERVER
) {
310 handle_client_request(addr
, data
, len
, iface
);
311 } else if (iface
->dhcpv6
== RELAYD_RELAY
) {
313 relay_server_response(data
, len
);
315 relay_client_request(addr
, data
, len
, iface
);
320 // Relay server response (regular relay server handling)
321 static void relay_server_response(uint8_t *data
, size_t len
)
323 // Information we need to gather
324 uint8_t *payload_data
= NULL
;
325 size_t payload_len
= 0;
326 int32_t ifaceidx
= 0;
327 struct sockaddr_in6 target
= {AF_INET6
, htons(DHCPV6_CLIENT_PORT
),
328 0, IN6ADDR_ANY_INIT
, 0};
330 syslog(LOG_NOTICE
, "Got a DHCPv6-reply");
333 uint8_t *odata
, *end
= data
+ len
;
335 // Relay DHCPv6 reply from server to client
336 struct dhcpv6_relay_header
*h
= (void*)data
;
337 if (len
< sizeof(*h
) || h
->msg_type
!= DHCPV6_MSG_RELAY_REPL
)
340 memcpy(&target
.sin6_addr
, &h
->peer_address
,
341 sizeof(struct in6_addr
));
343 // Go through options and find what we need
344 dhcpv6_for_each_option(h
->options
, end
, otype
, olen
, odata
) {
345 if (otype
== DHCPV6_OPT_INTERFACE_ID
346 && olen
== sizeof(ifaceidx
)) {
347 memcpy(&ifaceidx
, odata
, sizeof(ifaceidx
));
348 } else if (otype
== DHCPV6_OPT_RELAY_MSG
) {
349 payload_data
= odata
;
354 // Invalid interface-id or basic payload
355 struct interface
*iface
= odhcpd_get_interface_by_index(ifaceidx
);
356 if (!iface
|| iface
->master
|| !payload_data
|| payload_len
< 4)
359 bool is_authenticated
= false;
360 struct in6_addr
*dns_ptr
= NULL
;
361 size_t dns_count
= 0;
363 // If the payload is relay-reply we have to send to the server port
364 if (payload_data
[0] == DHCPV6_MSG_RELAY_REPL
) {
365 target
.sin6_port
= htons(DHCPV6_SERVER_PORT
);
366 } else { // Go through the payload data
367 struct dhcpv6_client_header
*h
= (void*)payload_data
;
368 end
= payload_data
+ payload_len
;
370 dhcpv6_for_each_option(&h
[1], end
, otype
, olen
, odata
) {
371 if (otype
== DHCPV6_OPT_DNS_SERVERS
&& olen
>= 16) {
372 dns_ptr
= (struct in6_addr
*)odata
;
373 dns_count
= olen
/ 16;
374 } else if (otype
== DHCPV6_OPT_AUTH
) {
375 is_authenticated
= true;
380 // Rewrite DNS servers if requested
381 if (iface
->always_rewrite_dns
&& dns_ptr
&& dns_count
> 0) {
382 if (is_authenticated
)
383 return; // Impossible to rewrite
385 struct odhcpd_ipaddr ip
;
386 const struct in6_addr
*rewrite
= iface
->dns
;
387 size_t rewrite_cnt
= iface
->dns_cnt
;
389 if (rewrite_cnt
== 0) {
390 if (odhcpd_get_interface_addresses(iface
->ifindex
, &ip
, 1) < 1)
391 return; // Unable to get interface address
397 // Copy over any other addresses
398 for (size_t i
= 0; i
< dns_count
; ++i
) {
399 size_t j
= (i
< rewrite_cnt
) ? i
: rewrite_cnt
- 1;
400 memcpy(&dns_ptr
[i
], &rewrite
[j
], sizeof(*rewrite
));
404 struct iovec iov
= {payload_data
, payload_len
};
405 odhcpd_send(iface
->dhcpv6_event
.uloop
.fd
, &target
, &iov
, 1, iface
);
409 // Relay client request (regular DHCPv6-relay)
410 static void relay_client_request(struct sockaddr_in6
*source
,
411 const void *data
, size_t len
, struct interface
*iface
)
413 struct interface
*master
= odhcpd_get_master_interface();
414 const struct dhcpv6_relay_header
*h
= data
;
415 if (!master
|| master
->dhcpv6
!= RELAYD_RELAY
||
416 h
->msg_type
== DHCPV6_MSG_RELAY_REPL
||
417 h
->msg_type
== DHCPV6_MSG_RECONFIGURE
||
418 h
->msg_type
== DHCPV6_MSG_REPLY
||
419 h
->msg_type
== DHCPV6_MSG_ADVERTISE
)
420 return; // Invalid message types for client
422 syslog(LOG_NOTICE
, "Got a DHCPv6-request");
424 // Construct our forwarding envelope
425 struct dhcpv6_relay_forward_envelope hdr
= {
426 .msg_type
= DHCPV6_MSG_RELAY_FORW
,
428 .interface_id_type
= htons(DHCPV6_OPT_INTERFACE_ID
),
429 .interface_id_len
= htons(sizeof(uint32_t)),
430 .relay_message_type
= htons(DHCPV6_OPT_RELAY_MSG
),
431 .relay_message_len
= htons(len
),
434 if (h
->msg_type
== DHCPV6_MSG_RELAY_FORW
) { // handle relay-forward
435 if (h
->hop_count
>= DHCPV6_HOP_COUNT_LIMIT
)
436 return; // Invalid hop count
438 hdr
.hop_count
= h
->hop_count
+ 1;
441 // use memcpy here as the destination fields are unaligned
442 uint32_t ifindex
= iface
->ifindex
;
443 memcpy(&hdr
.peer_address
, &source
->sin6_addr
, sizeof(struct in6_addr
));
444 memcpy(&hdr
.interface_id_data
, &ifindex
, sizeof(ifindex
));
446 // Detect public IP of slave interface to use as link-address
447 struct odhcpd_ipaddr ip
;
448 if (odhcpd_get_interface_addresses(iface
->ifindex
, &ip
, 1) < 1) {
449 // No suitable address! Is the slave not configured yet?
450 // Detect public IP of master interface and use it instead
451 // This is WRONG and probably violates the RFC. However
452 // otherwise we have a hen and egg problem because the
453 // slave-interface cannot be auto-configured.
454 if (odhcpd_get_interface_addresses(master
->ifindex
, &ip
, 1) < 1)
455 return; // Could not obtain a suitable address
457 memcpy(&hdr
.link_address
, &ip
.addr
, sizeof(hdr
.link_address
));
459 struct sockaddr_in6 dhcpv6_servers
= {AF_INET6
,
460 htons(DHCPV6_SERVER_PORT
), 0, ALL_DHCPV6_SERVERS
, 0};
461 struct iovec iov
[2] = {{&hdr
, sizeof(hdr
)}, {(void*)data
, len
}};
462 odhcpd_send(iface
->dhcpv6_event
.uloop
.fd
, &dhcpv6_servers
, iov
, 2, master
);