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
== MODE_SERVER
)
91 setsockopt(sock
, IPPROTO_IPV6
, IPV6_ADD_MEMBERSHIP
, &server
, sizeof(server
));
93 iface
->dhcpv6_event
.uloop
.fd
= sock
;
94 iface
->dhcpv6_event
.handle_dgram
= handle_dhcpv6
;
95 odhcpd_register(&iface
->dhcpv6_event
);
98 return setup_dhcpv6_ia_interface(iface
, enable
);
105 #define IOV_STAT IOV_MAXRT
111 #define IOV_REFRESH IOV_PDBUF
118 static void handle_nested_message(uint8_t *data
, size_t len
,
119 uint8_t **opts
, uint8_t **end
, struct iovec iov
[IOV_TOTAL
- 1])
121 struct dhcpv6_relay_header
*hdr
= (struct dhcpv6_relay_header
*)data
;
122 if (iov
[IOV_NESTED
].iov_base
== NULL
) {
123 iov
[IOV_NESTED
].iov_base
= data
;
124 iov
[IOV_NESTED
].iov_len
= len
;
127 if (len
< sizeof(struct dhcpv6_client_header
))
130 if (hdr
->msg_type
!= DHCPV6_MSG_RELAY_FORW
) {
131 iov
[IOV_NESTED
].iov_len
= data
- (uint8_t*)iov
[IOV_NESTED
].iov_base
;
132 struct dhcpv6_client_header
*hdr
= (void*)data
;
133 *opts
= (uint8_t*)&hdr
[1];
138 uint16_t otype
, olen
;
140 dhcpv6_for_each_option(hdr
->options
, data
+ len
, otype
, olen
, odata
) {
141 if (otype
== DHCPV6_OPT_RELAY_MSG
) {
142 iov
[IOV_RELAY_MSG
].iov_base
= odata
+ olen
;
143 iov
[IOV_RELAY_MSG
].iov_len
= (((uint8_t*)iov
[IOV_NESTED
].iov_base
) +
144 iov
[IOV_NESTED
].iov_len
) - (odata
+ olen
);
145 handle_nested_message(odata
, olen
, opts
, end
, iov
);
152 static void update_nested_message(uint8_t *data
, size_t len
, ssize_t pdiff
)
154 struct dhcpv6_relay_header
*hdr
= (struct dhcpv6_relay_header
*)data
;
155 if (hdr
->msg_type
!= DHCPV6_MSG_RELAY_FORW
)
158 hdr
->msg_type
= DHCPV6_MSG_RELAY_REPL
;
160 uint16_t otype
, olen
;
162 dhcpv6_for_each_option(hdr
->options
, data
+ len
, otype
, olen
, odata
) {
163 if (otype
== DHCPV6_OPT_RELAY_MSG
) {
165 odata
[-2] = (olen
>> 8) & 0xff;
166 odata
[-1] = olen
& 0xff;
167 update_nested_message(odata
, olen
- pdiff
, pdiff
);
173 // Simple DHCPv6-server for information requests
174 static void handle_client_request(void *addr
, void *data
, size_t len
,
175 struct interface
*iface
, void *dest_addr
)
177 struct dhcpv6_client_header
*hdr
= data
;
179 if (len
< sizeof(*hdr
))
182 syslog(LOG_NOTICE
, "Got DHCPv6 request");
184 // Construct reply message
185 struct __attribute__((packed
)) {
188 uint16_t serverid_type
;
189 uint16_t serverid_length
;
191 uint16_t hardware_type
;
193 uint16_t clientid_type
;
194 uint16_t clientid_length
;
195 uint8_t clientid_buf
[130];
197 .msg_type
= DHCPV6_MSG_REPLY
,
198 .serverid_type
= htons(DHCPV6_OPT_SERVERID
),
199 .serverid_length
= htons(10),
200 .duid_type
= htons(3),
201 .hardware_type
= htons(1),
202 .clientid_type
= htons(DHCPV6_OPT_CLIENTID
),
205 odhcpd_get_mac(iface
, dest
.mac
);
207 struct __attribute__((packed
)) {
211 } maxrt
= {htons(DHCPV6_OPT_SOL_MAX_RT
), htons(sizeof(maxrt
) - 4),
214 struct __attribute__((packed
)) {
218 } stat
= {htons(DHCPV6_OPT_STATUS
), htons(sizeof(stat
) - 4),
219 htons(DHCPV6_STATUS_USEMULTICAST
)};
221 struct __attribute__((packed
)) {
225 } refresh
= {htons(DHCPV6_OPT_INFO_REFRESH
), htons(sizeof(uint32_t)),
228 struct in6_addr dns_addr
, *dns_addr_ptr
= iface
->dns
;
229 size_t dns_cnt
= iface
->dns_cnt
;
231 if ((dns_cnt
== 0) &&
232 !odhcpd_get_interface_dns_addr(iface
, &dns_addr
)) {
233 dns_addr_ptr
= &dns_addr
;
240 } dns
= {htons(DHCPV6_OPT_DNS_SERVERS
), htons(dns_cnt
* sizeof(*dns_addr_ptr
))};
244 // DNS Search options
245 uint8_t search_buf
[256], *search_domain
= iface
->search
;
246 size_t search_len
= iface
->search_len
;
248 if (!search_domain
&& !res_init() && _res
.dnsrch
[0] && _res
.dnsrch
[0][0]) {
249 int len
= dn_comp(_res
.dnsrch
[0], search_buf
,
250 sizeof(search_buf
), NULL
, NULL
);
252 search_domain
= search_buf
;
260 } search
= {htons(DHCPV6_OPT_DNS_DOMAIN
), htons(search_len
)};
263 struct dhcpv6_cer_id cerid
= {
265 .type
= htons(EXT_CER_ID
),
268 .addr
= iface
->dhcpv6_pd_cer
,
273 struct iovec iov
[IOV_TOTAL
] = {
274 [IOV_NESTED
] = {NULL
, 0},
275 [IOV_DEST
] = {&dest
, (uint8_t*)&dest
.clientid_type
- (uint8_t*)&dest
},
276 [IOV_MAXRT
] = {&maxrt
, sizeof(maxrt
)},
277 [IOV_DNS
] = {&dns
, (dns_cnt
) ? sizeof(dns
) : 0},
278 [IOV_DNS_ADDR
] = {dns_addr_ptr
, dns_cnt
* sizeof(*dns_addr_ptr
)},
279 [IOV_SEARCH
] = {&search
, (search_len
) ? sizeof(search
) : 0},
280 [IOV_SEARCH_DOMAIN
] = {search_domain
, search_len
},
281 [IOV_PDBUF
] = {pdbuf
, 0},
282 [IOV_CERID
] = {&cerid
, 0},
283 [IOV_DHCPV6_RAW
] = {iface
->dhcpv6_raw
, iface
->dhcpv6_raw_len
},
284 [IOV_RELAY_MSG
] = {NULL
, 0}
287 uint8_t *opts
= (uint8_t*)&hdr
[1], *opts_end
= (uint8_t*)data
+ len
;
288 if (hdr
->msg_type
== DHCPV6_MSG_RELAY_FORW
)
289 handle_nested_message(data
, len
, &opts
, &opts_end
, iov
);
291 memcpy(dest
.tr_id
, &opts
[-3], sizeof(dest
.tr_id
));
293 if (opts
[-4] == DHCPV6_MSG_ADVERTISE
|| opts
[-4] == DHCPV6_MSG_REPLY
|| opts
[-4] == DHCPV6_MSG_RELAY_REPL
)
296 if (!IN6_IS_ADDR_MULTICAST((struct in6_addr
*)dest_addr
) && iov
[IOV_NESTED
].iov_len
== 0 &&
297 (opts
[-4] == DHCPV6_MSG_SOLICIT
|| opts
[-4] == DHCPV6_MSG_CONFIRM
||
298 opts
[-4] == DHCPV6_MSG_REBIND
|| opts
[-4] == DHCPV6_MSG_INFORMATION_REQUEST
))
301 if (opts
[-4] == DHCPV6_MSG_SOLICIT
) {
302 dest
.msg_type
= DHCPV6_MSG_ADVERTISE
;
303 } else if (opts
[-4] == DHCPV6_MSG_INFORMATION_REQUEST
) {
304 iov
[IOV_REFRESH
].iov_base
= &refresh
;
305 iov
[IOV_REFRESH
].iov_len
= sizeof(refresh
);
307 // Return inf max rt option in reply to information request
308 maxrt
.type
= htons(DHCPV6_OPT_INF_MAX_RT
);
311 // Go through options and find what we need
312 uint16_t otype
, olen
;
314 dhcpv6_for_each_option(opts
, opts_end
, otype
, olen
, odata
) {
315 if (otype
== DHCPV6_OPT_CLIENTID
&& olen
<= 130) {
316 dest
.clientid_length
= htons(olen
);
317 memcpy(dest
.clientid_buf
, odata
, olen
);
318 iov
[IOV_DEST
].iov_len
+= 4 + olen
;
319 } else if (otype
== DHCPV6_OPT_SERVERID
) {
320 if (olen
!= ntohs(dest
.serverid_length
) ||
321 memcmp(odata
, &dest
.duid_type
, olen
))
322 return; // Not for us
323 } else if (iface
->filter_class
&& otype
== DHCPV6_OPT_USER_CLASS
) {
324 uint8_t *c
= odata
, *cend
= &odata
[olen
];
325 for (; &c
[2] <= cend
&& &c
[2 + (c
[0] << 8) + c
[1]] <= cend
; c
= &c
[2 + (c
[0] << 8) + c
[1]]) {
326 size_t elen
= strlen(iface
->filter_class
);
327 if (((((size_t)c
[0]) << 8) | c
[1]) == elen
&& !memcmp(&c
[2], iface
->filter_class
, elen
))
328 return; // Ignore from homenet
330 } else if (otype
== DHCPV6_OPT_IA_PD
) {
332 iov
[IOV_CERID
].iov_len
= sizeof(cerid
);
334 if (IN6_IS_ADDR_UNSPECIFIED(&cerid
.addr
)) {
335 struct odhcpd_ipaddr
*addrs
;
336 ssize_t len
= odhcpd_get_interface_addresses(0, true, &addrs
);
338 for (ssize_t i
= 0; i
< len
; ++i
)
339 if (IN6_IS_ADDR_UNSPECIFIED(&cerid
.addr
)
340 || memcmp(&addrs
[i
].addr
, &cerid
.addr
, sizeof(cerid
.addr
)) < 0)
341 cerid
.addr
= addrs
[i
].addr
;
349 if (!IN6_IS_ADDR_MULTICAST((struct in6_addr
*)dest_addr
) && iov
[IOV_NESTED
].iov_len
== 0 &&
350 (opts
[-4] == DHCPV6_MSG_REQUEST
|| opts
[-4] == DHCPV6_MSG_RENEW
||
351 opts
[-4] == DHCPV6_MSG_RELEASE
|| opts
[-4] == DHCPV6_MSG_DECLINE
)) {
352 iov
[IOV_STAT
].iov_base
= &stat
;
353 iov
[IOV_STAT
].iov_len
= sizeof(stat
);
355 for (ssize_t i
= IOV_STAT
+ 1; i
< IOV_TOTAL
; ++i
)
358 odhcpd_send(iface
->dhcpv6_event
.uloop
.fd
, addr
, iov
, ARRAY_SIZE(iov
), iface
);
362 if (opts
[-4] != DHCPV6_MSG_INFORMATION_REQUEST
) {
363 ssize_t ialen
= dhcpv6_handle_ia(pdbuf
, sizeof(pdbuf
), iface
, addr
, &opts
[-4], opts_end
);
364 iov
[IOV_PDBUF
].iov_len
= ialen
;
365 if (ialen
< 0 || (ialen
== 0 && (opts
[-4] == DHCPV6_MSG_REBIND
|| opts
[-4] == DHCPV6_MSG_CONFIRM
)))
369 if (iov
[IOV_NESTED
].iov_len
> 0) // Update length
370 update_nested_message(data
, len
, iov
[IOV_DEST
].iov_len
+ iov
[IOV_MAXRT
].iov_len
+
371 iov
[IOV_DNS
].iov_len
+ iov
[IOV_DNS_ADDR
].iov_len
+
372 iov
[IOV_SEARCH
].iov_len
+ iov
[IOV_SEARCH_DOMAIN
].iov_len
+
373 iov
[IOV_PDBUF
].iov_len
+ iov
[IOV_CERID
].iov_len
+
374 iov
[IOV_DHCPV6_RAW
].iov_len
- (4 + opts_end
- opts
));
376 odhcpd_send(iface
->dhcpv6_event
.uloop
.fd
, addr
, iov
, ARRAY_SIZE(iov
), iface
);
380 // Central DHCPv6-relay handler
381 static void handle_dhcpv6(void *addr
, void *data
, size_t len
,
382 struct interface
*iface
, void *dest_addr
)
384 if (iface
->dhcpv6
== MODE_SERVER
) {
385 handle_client_request(addr
, data
, len
, iface
, dest_addr
);
386 } else if (iface
->dhcpv6
== MODE_RELAY
) {
388 relay_server_response(data
, len
);
390 relay_client_request(addr
, data
, len
, iface
);
395 // Relay server response (regular relay server handling)
396 static void relay_server_response(uint8_t *data
, size_t len
)
398 // Information we need to gather
399 uint8_t *payload_data
= NULL
;
400 size_t payload_len
= 0;
401 int32_t ifaceidx
= 0;
402 struct sockaddr_in6 target
= {AF_INET6
, htons(DHCPV6_CLIENT_PORT
),
403 0, IN6ADDR_ANY_INIT
, 0};
405 syslog(LOG_NOTICE
, "Got a DHCPv6-reply");
408 uint8_t *odata
, *end
= data
+ len
;
410 // Relay DHCPv6 reply from server to client
411 struct dhcpv6_relay_header
*h
= (void*)data
;
412 if (len
< sizeof(*h
) || h
->msg_type
!= DHCPV6_MSG_RELAY_REPL
)
415 memcpy(&target
.sin6_addr
, &h
->peer_address
,
416 sizeof(struct in6_addr
));
418 // Go through options and find what we need
419 dhcpv6_for_each_option(h
->options
, end
, otype
, olen
, odata
) {
420 if (otype
== DHCPV6_OPT_INTERFACE_ID
421 && olen
== sizeof(ifaceidx
)) {
422 memcpy(&ifaceidx
, odata
, sizeof(ifaceidx
));
423 } else if (otype
== DHCPV6_OPT_RELAY_MSG
) {
424 payload_data
= odata
;
429 // Invalid interface-id or basic payload
430 struct interface
*iface
= odhcpd_get_interface_by_index(ifaceidx
);
431 if (!iface
|| iface
->master
|| !payload_data
|| payload_len
< 4)
434 bool is_authenticated
= false;
435 struct in6_addr
*dns_ptr
= NULL
;
436 size_t dns_count
= 0;
438 // If the payload is relay-reply we have to send to the server port
439 if (payload_data
[0] == DHCPV6_MSG_RELAY_REPL
) {
440 target
.sin6_port
= htons(DHCPV6_SERVER_PORT
);
441 } else { // Go through the payload data
442 struct dhcpv6_client_header
*h
= (void*)payload_data
;
443 end
= payload_data
+ payload_len
;
445 dhcpv6_for_each_option(&h
[1], end
, otype
, olen
, odata
) {
446 if (otype
== DHCPV6_OPT_DNS_SERVERS
&& olen
>= 16) {
447 dns_ptr
= (struct in6_addr
*)odata
;
448 dns_count
= olen
/ 16;
449 } else if (otype
== DHCPV6_OPT_AUTH
) {
450 is_authenticated
= true;
455 // Rewrite DNS servers if requested
456 if (iface
->always_rewrite_dns
&& dns_ptr
&& dns_count
> 0) {
457 if (is_authenticated
)
458 return; // Impossible to rewrite
460 const struct in6_addr
*rewrite
= iface
->dns
;
461 struct in6_addr addr
;
462 size_t rewrite_cnt
= iface
->dns_cnt
;
464 if (rewrite_cnt
== 0) {
465 if (odhcpd_get_interface_dns_addr(iface
, &addr
))
466 return; // Unable to get interface address
472 // Copy over any other addresses
473 for (size_t i
= 0; i
< dns_count
; ++i
) {
474 size_t j
= (i
< rewrite_cnt
) ? i
: rewrite_cnt
- 1;
475 memcpy(&dns_ptr
[i
], &rewrite
[j
], sizeof(*rewrite
));
479 struct iovec iov
= {payload_data
, payload_len
};
480 odhcpd_send(iface
->dhcpv6_event
.uloop
.fd
, &target
, &iov
, 1, iface
);
483 static struct odhcpd_ipaddr
*relay_link_address(struct interface
*iface
)
485 struct odhcpd_ipaddr
*addr
= NULL
;
486 time_t now
= odhcpd_time();
488 for (size_t i
= 0; i
< iface
->ia_addr_len
; i
++) {
489 if (iface
->ia_addr
[i
].valid
<= (uint32_t)now
)
492 if (iface
->ia_addr
[i
].preferred
> (uint32_t)now
) {
493 addr
= &iface
->ia_addr
[i
];
497 if (!addr
|| (iface
->ia_addr
[i
].valid
> addr
->valid
))
498 addr
= &iface
->ia_addr
[i
];
504 // Relay client request (regular DHCPv6-relay)
505 static void relay_client_request(struct sockaddr_in6
*source
,
506 const void *data
, size_t len
, struct interface
*iface
)
508 struct interface
*master
= odhcpd_get_master_interface();
509 const struct dhcpv6_relay_header
*h
= data
;
510 if (!master
|| master
->dhcpv6
!= MODE_RELAY
||
511 h
->msg_type
== DHCPV6_MSG_RELAY_REPL
||
512 h
->msg_type
== DHCPV6_MSG_RECONFIGURE
||
513 h
->msg_type
== DHCPV6_MSG_REPLY
||
514 h
->msg_type
== DHCPV6_MSG_ADVERTISE
)
515 return; // Invalid message types for client
517 syslog(LOG_NOTICE
, "Got a DHCPv6-request");
519 // Construct our forwarding envelope
520 struct dhcpv6_relay_forward_envelope hdr
= {
521 .msg_type
= DHCPV6_MSG_RELAY_FORW
,
523 .interface_id_type
= htons(DHCPV6_OPT_INTERFACE_ID
),
524 .interface_id_len
= htons(sizeof(uint32_t)),
525 .relay_message_type
= htons(DHCPV6_OPT_RELAY_MSG
),
526 .relay_message_len
= htons(len
),
529 if (h
->msg_type
== DHCPV6_MSG_RELAY_FORW
) { // handle relay-forward
530 if (h
->hop_count
>= DHCPV6_HOP_COUNT_LIMIT
)
531 return; // Invalid hop count
533 hdr
.hop_count
= h
->hop_count
+ 1;
536 // use memcpy here as the destination fields are unaligned
537 uint32_t ifindex
= iface
->ifindex
;
538 memcpy(&hdr
.peer_address
, &source
->sin6_addr
, sizeof(struct in6_addr
));
539 memcpy(&hdr
.interface_id_data
, &ifindex
, sizeof(ifindex
));
541 // Detect public IP of slave interface to use as link-address
542 struct odhcpd_ipaddr
*ip
= relay_link_address(iface
);
544 // No suitable address! Is the slave not configured yet?
545 // Detect public IP of master interface and use it instead
546 // This is WRONG and probably violates the RFC. However
547 // otherwise we have a hen and egg problem because the
548 // slave-interface cannot be auto-configured.
549 ip
= relay_link_address(master
);
551 return; // Could not obtain a suitable address
554 memcpy(&hdr
.link_address
, &ip
->addr
.in6
, sizeof(hdr
.link_address
));
556 struct sockaddr_in6 dhcpv6_servers
= {AF_INET6
,
557 htons(DHCPV6_SERVER_PORT
), 0, ALL_DHCPV6_SERVERS
, 0};
558 struct iovec iov
[2] = {{&hdr
, sizeof(hdr
)}, {(void*)data
, len
}};
559 odhcpd_send(master
->dhcpv6_event
.uloop
.fd
, &dhcpv6_servers
, iov
, 2, master
);