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>
21 #include <arpa/inet.h>
27 static void relay_client_request(struct sockaddr_in6
*source
,
28 const void *data
, size_t len
, struct interface
*iface
);
29 static void relay_server_response(uint8_t *data
, size_t len
);
31 static void handle_dhcpv6(void *addr
, void *data
, size_t len
,
32 struct interface
*iface
, void *dest
);
33 static void handle_client_request(void *addr
, void *data
, size_t len
,
34 struct interface
*iface
, void *dest_addr
);
38 // Create socket and register events
46 int setup_dhcpv6_interface(struct interface
*iface
, bool enable
)
48 if (iface
->dhcpv6_event
.uloop
.fd
> 0) {
49 uloop_fd_delete(&iface
->dhcpv6_event
.uloop
);
50 close(iface
->dhcpv6_event
.uloop
.fd
);
51 iface
->dhcpv6_event
.uloop
.fd
= -1;
54 // Configure multicast settings
55 if (enable
&& iface
->dhcpv6
) {
56 int sock
= socket(AF_INET6
, SOCK_DGRAM
| SOCK_CLOEXEC
, IPPROTO_UDP
);
58 syslog(LOG_ERR
, "Failed to create DHCPv6 server socket: %s",
63 // Basic IPv6 configuration
64 setsockopt(sock
, SOL_SOCKET
, SO_BINDTODEVICE
, iface
->ifname
, strlen(iface
->ifname
));
67 setsockopt(sock
, IPPROTO_IPV6
, IPV6_V6ONLY
, &val
, sizeof(val
));
68 setsockopt(sock
, SOL_SOCKET
, SO_REUSEADDR
, &val
, sizeof(val
));
69 setsockopt(sock
, IPPROTO_IPV6
, IPV6_RECVPKTINFO
, &val
, sizeof(val
));
71 val
= DHCPV6_HOP_COUNT_LIMIT
;
72 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
));
75 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_LOOP
, &val
, sizeof(val
));
77 struct sockaddr_in6 bind_addr
= {AF_INET6
, htons(DHCPV6_SERVER_PORT
),
78 0, IN6ADDR_ANY_INIT
, 0};
80 if (bind(sock
, (struct sockaddr
*)&bind_addr
, sizeof(bind_addr
))) {
81 syslog(LOG_ERR
, "Failed to open DHCPv6 server socket: %s",
86 struct ipv6_mreq relay
= {ALL_DHCPV6_RELAYS
, iface
->ifindex
};
87 struct ipv6_mreq server
= {ALL_DHCPV6_SERVERS
, iface
->ifindex
};
88 setsockopt(sock
, IPPROTO_IPV6
, IPV6_ADD_MEMBERSHIP
, &relay
, sizeof(relay
));
90 if (iface
->dhcpv6
== RELAYD_SERVER
)
91 setsockopt(sock
, IPPROTO_IPV6
, IPV6_ADD_MEMBERSHIP
, &server
, sizeof(server
));
93 if (iface
->dhcpv6
!= RELAYD_RELAY
|| !iface
->master
)
96 iface
->dhcpv6_event
.uloop
.fd
= sock
;
97 iface
->dhcpv6_event
.handle_dgram
= handle_dhcpv6
;
98 odhcpd_register(&iface
->dhcpv6_event
);
101 return setup_dhcpv6_ia_interface(iface
, enable
);
108 #define IOV_STAT IOV_MAXRT
114 #define IOV_REFRESH IOV_PDBUF
121 static void handle_nested_message(uint8_t *data
, size_t len
,
122 uint8_t **opts
, uint8_t **end
, struct iovec iov
[IOV_TOTAL
- 1])
124 struct dhcpv6_relay_header
*hdr
= (struct dhcpv6_relay_header
*)data
;
125 if (iov
[IOV_NESTED
].iov_base
== NULL
) {
126 iov
[IOV_NESTED
].iov_base
= data
;
127 iov
[IOV_NESTED
].iov_len
= len
;
130 if (len
< sizeof(struct dhcpv6_client_header
))
133 if (hdr
->msg_type
!= DHCPV6_MSG_RELAY_FORW
) {
134 iov
[IOV_NESTED
].iov_len
= data
- (uint8_t*)iov
[IOV_NESTED
].iov_base
;
135 struct dhcpv6_client_header
*hdr
= (void*)data
;
136 *opts
= (uint8_t*)&hdr
[1];
141 uint16_t otype
, olen
;
143 dhcpv6_for_each_option(hdr
->options
, data
+ len
, otype
, olen
, odata
) {
144 if (otype
== DHCPV6_OPT_RELAY_MSG
) {
145 iov
[IOV_RELAY_MSG
].iov_base
= odata
+ olen
;
146 iov
[IOV_RELAY_MSG
].iov_len
= (((uint8_t*)iov
[IOV_NESTED
].iov_base
) +
147 iov
[IOV_NESTED
].iov_len
) - (odata
+ olen
);
148 handle_nested_message(odata
, olen
, opts
, end
, iov
);
155 static void update_nested_message(uint8_t *data
, size_t len
, ssize_t pdiff
)
157 struct dhcpv6_relay_header
*hdr
= (struct dhcpv6_relay_header
*)data
;
158 if (hdr
->msg_type
!= DHCPV6_MSG_RELAY_FORW
)
161 hdr
->msg_type
= DHCPV6_MSG_RELAY_REPL
;
163 uint16_t otype
, olen
;
165 dhcpv6_for_each_option(hdr
->options
, data
+ len
, otype
, olen
, odata
) {
166 if (otype
== DHCPV6_OPT_RELAY_MSG
) {
168 odata
[-2] = (olen
>> 8) & 0xff;
169 odata
[-1] = olen
& 0xff;
170 update_nested_message(odata
, olen
- pdiff
, pdiff
);
176 // Simple DHCPv6-server for information requests
177 static void handle_client_request(void *addr
, void *data
, size_t len
,
178 struct interface
*iface
, void *dest_addr
)
180 struct dhcpv6_client_header
*hdr
= data
;
182 if (len
< sizeof(*hdr
))
185 syslog(LOG_NOTICE
, "Got DHCPv6 request");
187 // Construct reply message
188 struct __attribute__((packed
)) {
191 uint16_t serverid_type
;
192 uint16_t serverid_length
;
194 uint16_t hardware_type
;
196 uint16_t clientid_type
;
197 uint16_t clientid_length
;
198 uint8_t clientid_buf
[130];
200 .msg_type
= DHCPV6_MSG_REPLY
,
201 .serverid_type
= htons(DHCPV6_OPT_SERVERID
),
202 .serverid_length
= htons(10),
203 .duid_type
= htons(3),
204 .hardware_type
= htons(1),
205 .clientid_type
= htons(DHCPV6_OPT_CLIENTID
),
208 odhcpd_get_mac(iface
, dest
.mac
);
210 struct __attribute__((packed
)) {
214 } maxrt
= {htons(DHCPV6_OPT_SOL_MAX_RT
), htons(sizeof(maxrt
) - 4),
217 struct __attribute__((packed
)) {
221 } stat
= {htons(DHCPV6_OPT_STATUS
), htons(sizeof(stat
) - 4),
222 htons(DHCPV6_STATUS_USEMULTICAST
)};
224 struct __attribute__((packed
)) {
228 } refresh
= {htons(DHCPV6_OPT_INFO_REFRESH
), htons(sizeof(uint32_t)),
231 struct in6_addr dns_addr
, *dns_addr_ptr
= iface
->dns
;
232 size_t dns_cnt
= iface
->dns_cnt
;
234 if ((dns_cnt
== 0) &&
235 !odhcpd_get_interface_dns_addr(iface
, &dns_addr
)) {
236 dns_addr_ptr
= &dns_addr
;
243 } dns
= {htons(DHCPV6_OPT_DNS_SERVERS
), htons(dns_cnt
* sizeof(*dns_addr_ptr
))};
247 // DNS Search options
248 uint8_t search_buf
[256], *search_domain
= iface
->search
;
249 size_t search_len
= iface
->search_len
;
251 if (!search_domain
&& !res_init() && _res
.dnsrch
[0] && _res
.dnsrch
[0][0]) {
252 int len
= dn_comp(_res
.dnsrch
[0], search_buf
,
253 sizeof(search_buf
), NULL
, NULL
);
255 search_domain
= search_buf
;
263 } search
= {htons(DHCPV6_OPT_DNS_DOMAIN
), htons(search_len
)};
266 struct dhcpv6_cer_id cerid
= {
268 .type
= htons(EXT_CER_ID
),
271 .addr
= iface
->dhcpv6_pd_cer
,
276 struct iovec iov
[IOV_TOTAL
] = {
277 [IOV_NESTED
] = {NULL
, 0},
278 [IOV_DEST
] = {&dest
, (uint8_t*)&dest
.clientid_type
- (uint8_t*)&dest
},
279 [IOV_MAXRT
] = {&maxrt
, sizeof(maxrt
)},
280 [IOV_DNS
] = {&dns
, (dns_cnt
) ? sizeof(dns
) : 0},
281 [IOV_DNS_ADDR
] = {dns_addr_ptr
, dns_cnt
* sizeof(*dns_addr_ptr
)},
282 [IOV_SEARCH
] = {&search
, (search_len
) ? sizeof(search
) : 0},
283 [IOV_SEARCH_DOMAIN
] = {search_domain
, search_len
},
284 [IOV_PDBUF
] = {pdbuf
, 0},
285 [IOV_CERID
] = {&cerid
, 0},
286 [IOV_DHCPV6_RAW
] = {iface
->dhcpv6_raw
, iface
->dhcpv6_raw_len
},
287 [IOV_RELAY_MSG
] = {NULL
, 0}
290 uint8_t *opts
= (uint8_t*)&hdr
[1], *opts_end
= (uint8_t*)data
+ len
;
291 if (hdr
->msg_type
== DHCPV6_MSG_RELAY_FORW
)
292 handle_nested_message(data
, len
, &opts
, &opts_end
, iov
);
294 memcpy(dest
.tr_id
, &opts
[-3], sizeof(dest
.tr_id
));
296 if (opts
[-4] == DHCPV6_MSG_ADVERTISE
|| opts
[-4] == DHCPV6_MSG_REPLY
|| opts
[-4] == DHCPV6_MSG_RELAY_REPL
)
299 if (!IN6_IS_ADDR_MULTICAST((struct in6_addr
*)dest_addr
) && iov
[IOV_NESTED
].iov_len
== 0 &&
300 (opts
[-4] == DHCPV6_MSG_SOLICIT
|| opts
[-4] == DHCPV6_MSG_CONFIRM
||
301 opts
[-4] == DHCPV6_MSG_REBIND
|| opts
[-4] == DHCPV6_MSG_INFORMATION_REQUEST
))
304 if (opts
[-4] == DHCPV6_MSG_SOLICIT
) {
305 dest
.msg_type
= DHCPV6_MSG_ADVERTISE
;
306 } else if (opts
[-4] == DHCPV6_MSG_INFORMATION_REQUEST
) {
307 iov
[IOV_REFRESH
].iov_base
= &refresh
;
308 iov
[IOV_REFRESH
].iov_len
= sizeof(refresh
);
310 // Return inf max rt option in reply to information request
311 maxrt
.type
= htons(DHCPV6_OPT_INF_MAX_RT
);
314 // Go through options and find what we need
315 uint16_t otype
, olen
;
317 dhcpv6_for_each_option(opts
, opts_end
, otype
, olen
, odata
) {
318 if (otype
== DHCPV6_OPT_CLIENTID
&& olen
<= 130) {
319 dest
.clientid_length
= htons(olen
);
320 memcpy(dest
.clientid_buf
, odata
, olen
);
321 iov
[IOV_DEST
].iov_len
+= 4 + olen
;
322 } else if (otype
== DHCPV6_OPT_SERVERID
) {
323 if (olen
!= ntohs(dest
.serverid_length
) ||
324 memcmp(odata
, &dest
.duid_type
, olen
))
325 return; // Not for us
326 } else if (iface
->filter_class
&& otype
== DHCPV6_OPT_USER_CLASS
) {
327 uint8_t *c
= odata
, *cend
= &odata
[olen
];
328 for (; &c
[2] <= cend
&& &c
[2 + (c
[0] << 8) + c
[1]] <= cend
; c
= &c
[2 + (c
[0] << 8) + c
[1]]) {
329 size_t elen
= strlen(iface
->filter_class
);
330 if (((((size_t)c
[0]) << 8) | c
[1]) == elen
&& !memcmp(&c
[2], iface
->filter_class
, elen
))
331 return; // Ignore from homenet
333 } else if (otype
== DHCPV6_OPT_IA_PD
) {
335 iov
[IOV_CERID
].iov_len
= sizeof(cerid
);
337 if (IN6_IS_ADDR_UNSPECIFIED(&cerid
.addr
)) {
338 struct odhcpd_ipaddr
*addrs
;
339 ssize_t len
= odhcpd_get_interface_addresses(0, &addrs
);
341 for (ssize_t i
= 0; i
< len
; ++i
)
342 if (IN6_IS_ADDR_UNSPECIFIED(&cerid
.addr
)
343 || memcmp(&addrs
[i
].addr
, &cerid
.addr
, sizeof(cerid
.addr
)) < 0)
344 cerid
.addr
= addrs
[i
].addr
;
352 if (!IN6_IS_ADDR_MULTICAST((struct in6_addr
*)dest_addr
) && iov
[IOV_NESTED
].iov_len
== 0 &&
353 (opts
[-4] == DHCPV6_MSG_REQUEST
|| opts
[-4] == DHCPV6_MSG_RENEW
||
354 opts
[-4] == DHCPV6_MSG_RELEASE
|| opts
[-4] == DHCPV6_MSG_DECLINE
)) {
355 iov
[IOV_STAT
].iov_base
= &stat
;
356 iov
[IOV_STAT
].iov_len
= sizeof(stat
);
358 for (ssize_t i
= IOV_STAT
+ 1; i
< IOV_TOTAL
; ++i
)
361 odhcpd_send(iface
->dhcpv6_event
.uloop
.fd
, addr
, iov
, ARRAY_SIZE(iov
), iface
);
365 if (opts
[-4] != DHCPV6_MSG_INFORMATION_REQUEST
) {
366 ssize_t ialen
= dhcpv6_handle_ia(pdbuf
, sizeof(pdbuf
), iface
, addr
, &opts
[-4], opts_end
);
367 iov
[IOV_PDBUF
].iov_len
= ialen
;
368 if (ialen
< 0 || (ialen
== 0 && (opts
[-4] == DHCPV6_MSG_REBIND
|| opts
[-4] == DHCPV6_MSG_CONFIRM
)))
372 if (iov
[IOV_NESTED
].iov_len
> 0) // Update length
373 update_nested_message(data
, len
, iov
[IOV_DEST
].iov_len
+ iov
[IOV_MAXRT
].iov_len
+
374 iov
[IOV_DNS
].iov_len
+ iov
[IOV_DNS_ADDR
].iov_len
+
375 iov
[IOV_SEARCH
].iov_len
+ iov
[IOV_SEARCH_DOMAIN
].iov_len
+
376 iov
[IOV_PDBUF
].iov_len
+ iov
[IOV_CERID
].iov_len
+
377 iov
[IOV_DHCPV6_RAW
].iov_len
- (4 + opts_end
- opts
));
379 odhcpd_send(iface
->dhcpv6_event
.uloop
.fd
, addr
, iov
, ARRAY_SIZE(iov
), iface
);
383 // Central DHCPv6-relay handler
384 static void handle_dhcpv6(void *addr
, void *data
, size_t len
,
385 struct interface
*iface
, void *dest_addr
)
387 if (iface
->dhcpv6
== RELAYD_SERVER
) {
388 handle_client_request(addr
, data
, len
, iface
, dest_addr
);
389 } else if (iface
->dhcpv6
== RELAYD_RELAY
) {
391 relay_server_response(data
, len
);
393 relay_client_request(addr
, data
, len
, iface
);
398 // Relay server response (regular relay server handling)
399 static void relay_server_response(uint8_t *data
, size_t len
)
401 // Information we need to gather
402 uint8_t *payload_data
= NULL
;
403 size_t payload_len
= 0;
404 int32_t ifaceidx
= 0;
405 struct sockaddr_in6 target
= {AF_INET6
, htons(DHCPV6_CLIENT_PORT
),
406 0, IN6ADDR_ANY_INIT
, 0};
408 syslog(LOG_NOTICE
, "Got a DHCPv6-reply");
411 uint8_t *odata
, *end
= data
+ len
;
413 // Relay DHCPv6 reply from server to client
414 struct dhcpv6_relay_header
*h
= (void*)data
;
415 if (len
< sizeof(*h
) || h
->msg_type
!= DHCPV6_MSG_RELAY_REPL
)
418 memcpy(&target
.sin6_addr
, &h
->peer_address
,
419 sizeof(struct in6_addr
));
421 // Go through options and find what we need
422 dhcpv6_for_each_option(h
->options
, end
, otype
, olen
, odata
) {
423 if (otype
== DHCPV6_OPT_INTERFACE_ID
424 && olen
== sizeof(ifaceidx
)) {
425 memcpy(&ifaceidx
, odata
, sizeof(ifaceidx
));
426 } else if (otype
== DHCPV6_OPT_RELAY_MSG
) {
427 payload_data
= odata
;
432 // Invalid interface-id or basic payload
433 struct interface
*iface
= odhcpd_get_interface_by_index(ifaceidx
);
434 if (!iface
|| iface
->master
|| !payload_data
|| payload_len
< 4)
437 bool is_authenticated
= false;
438 struct in6_addr
*dns_ptr
= NULL
;
439 size_t dns_count
= 0;
441 // If the payload is relay-reply we have to send to the server port
442 if (payload_data
[0] == DHCPV6_MSG_RELAY_REPL
) {
443 target
.sin6_port
= htons(DHCPV6_SERVER_PORT
);
444 } else { // Go through the payload data
445 struct dhcpv6_client_header
*h
= (void*)payload_data
;
446 end
= payload_data
+ payload_len
;
448 dhcpv6_for_each_option(&h
[1], end
, otype
, olen
, odata
) {
449 if (otype
== DHCPV6_OPT_DNS_SERVERS
&& olen
>= 16) {
450 dns_ptr
= (struct in6_addr
*)odata
;
451 dns_count
= olen
/ 16;
452 } else if (otype
== DHCPV6_OPT_AUTH
) {
453 is_authenticated
= true;
458 // Rewrite DNS servers if requested
459 if (iface
->always_rewrite_dns
&& dns_ptr
&& dns_count
> 0) {
460 if (is_authenticated
)
461 return; // Impossible to rewrite
463 const struct in6_addr
*rewrite
= iface
->dns
;
464 struct in6_addr addr
;
465 size_t rewrite_cnt
= iface
->dns_cnt
;
467 if (rewrite_cnt
== 0) {
468 if (odhcpd_get_interface_dns_addr(iface
, &addr
))
469 return; // Unable to get interface address
475 // Copy over any other addresses
476 for (size_t i
= 0; i
< dns_count
; ++i
) {
477 size_t j
= (i
< rewrite_cnt
) ? i
: rewrite_cnt
- 1;
478 memcpy(&dns_ptr
[i
], &rewrite
[j
], sizeof(*rewrite
));
482 struct iovec iov
= {payload_data
, payload_len
};
483 odhcpd_send(iface
->dhcpv6_event
.uloop
.fd
, &target
, &iov
, 1, iface
);
487 // Relay client request (regular DHCPv6-relay)
488 static void relay_client_request(struct sockaddr_in6
*source
,
489 const void *data
, size_t len
, struct interface
*iface
)
491 struct interface
*master
= odhcpd_get_master_interface();
492 const struct dhcpv6_relay_header
*h
= data
;
493 if (!master
|| master
->dhcpv6
!= RELAYD_RELAY
||
494 h
->msg_type
== DHCPV6_MSG_RELAY_REPL
||
495 h
->msg_type
== DHCPV6_MSG_RECONFIGURE
||
496 h
->msg_type
== DHCPV6_MSG_REPLY
||
497 h
->msg_type
== DHCPV6_MSG_ADVERTISE
)
498 return; // Invalid message types for client
500 syslog(LOG_NOTICE
, "Got a DHCPv6-request");
502 // Construct our forwarding envelope
503 struct dhcpv6_relay_forward_envelope hdr
= {
504 .msg_type
= DHCPV6_MSG_RELAY_FORW
,
506 .interface_id_type
= htons(DHCPV6_OPT_INTERFACE_ID
),
507 .interface_id_len
= htons(sizeof(uint32_t)),
508 .relay_message_type
= htons(DHCPV6_OPT_RELAY_MSG
),
509 .relay_message_len
= htons(len
),
512 if (h
->msg_type
== DHCPV6_MSG_RELAY_FORW
) { // handle relay-forward
513 if (h
->hop_count
>= DHCPV6_HOP_COUNT_LIMIT
)
514 return; // Invalid hop count
516 hdr
.hop_count
= h
->hop_count
+ 1;
519 // use memcpy here as the destination fields are unaligned
520 uint32_t ifindex
= iface
->ifindex
;
521 memcpy(&hdr
.peer_address
, &source
->sin6_addr
, sizeof(struct in6_addr
));
522 memcpy(&hdr
.interface_id_data
, &ifindex
, sizeof(ifindex
));
524 // Detect public IP of slave interface to use as link-address
525 struct odhcpd_ipaddr
*ip
= NULL
;
526 if (odhcpd_get_interface_addresses(iface
->ifindex
, &ip
) < 1) {
527 // No suitable address! Is the slave not configured yet?
528 // Detect public IP of master interface and use it instead
529 // This is WRONG and probably violates the RFC. However
530 // otherwise we have a hen and egg problem because the
531 // slave-interface cannot be auto-configured.
532 if (odhcpd_get_interface_addresses(master
->ifindex
, &ip
) < 1)
533 return; // Could not obtain a suitable address
535 memcpy(&hdr
.link_address
, &ip
[0].addr
, sizeof(hdr
.link_address
));
538 struct sockaddr_in6 dhcpv6_servers
= {AF_INET6
,
539 htons(DHCPV6_SERVER_PORT
), 0, ALL_DHCPV6_SERVERS
, 0};
540 struct iovec iov
[2] = {{&hdr
, sizeof(hdr
)}, {(void*)data
, len
}};
541 odhcpd_send(master
->dhcpv6_event
.uloop
.fd
, &dhcpv6_servers
, iov
, 2, master
);