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.
23 #include <net/route.h>
29 static void forward_router_solicitation(const struct interface
*iface
);
30 static void forward_router_advertisement(uint8_t *data
, size_t len
);
32 static void handle_icmpv6(void *addr
, void *data
, size_t len
,
33 struct interface
*iface
, void *dest
);
34 static void trigger_router_advert(struct uloop_timeout
*event
);
35 static void sigusr1_refresh(int signal
);
37 static struct odhcpd_event router_event
= {{.fd
= -1}, handle_icmpv6
, NULL
};
39 static FILE *fp_route
= NULL
;
42 #define TIME_LEFT(t1, now) ((t1) != UINT32_MAX ? (t1) - (now) : UINT32_MAX)
47 int sock
= socket(AF_INET6
, SOCK_RAW
| SOCK_CLOEXEC
, IPPROTO_ICMPV6
);
48 if (sock
< 0 && errno
!= EAFNOSUPPORT
) {
49 syslog(LOG_ERR
, "Failed to open RAW-socket: %s", strerror(errno
));
53 // Let the kernel compute our checksums
55 setsockopt(sock
, IPPROTO_RAW
, IPV6_CHECKSUM
, &val
, sizeof(val
));
57 // This is required by RFC 4861
59 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
));
60 setsockopt(sock
, IPPROTO_IPV6
, IPV6_UNICAST_HOPS
, &val
, sizeof(val
));
62 // We need to know the source interface
64 setsockopt(sock
, IPPROTO_IPV6
, IPV6_RECVPKTINFO
, &val
, sizeof(val
));
65 setsockopt(sock
, IPPROTO_IPV6
, IPV6_RECVHOPLIMIT
, &val
, sizeof(val
));
69 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_LOOP
, &val
, sizeof(val
));
71 // Filter ICMPv6 package types
72 struct icmp6_filter filt
;
73 ICMP6_FILTER_SETBLOCKALL(&filt
);
74 ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT
, &filt
);
75 ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT
, &filt
);
76 setsockopt(sock
, IPPROTO_ICMPV6
, ICMP6_FILTER
, &filt
, sizeof(filt
));
79 router_event
.uloop
.fd
= sock
;
80 odhcpd_register(&router_event
);
82 if (!(fp_route
= fopen("/proc/net/ipv6_route", "r")))
83 syslog(LOG_ERR
, "Failed to open routing table: %s",
86 signal(SIGUSR1
, sigusr1_refresh
);
91 int setup_router_interface(struct interface
*iface
, bool enable
)
93 if (!fp_route
|| router_event
.uloop
.fd
< 0)
96 struct ipv6_mreq all_nodes
= {ALL_IPV6_NODES
, iface
->ifindex
};
97 struct ipv6_mreq all_routers
= {ALL_IPV6_ROUTERS
, iface
->ifindex
};
99 uloop_timeout_cancel(&iface
->timer_rs
);
100 iface
->timer_rs
.cb
= NULL
;
102 if (iface
->ifindex
<= 0)
105 setsockopt(router_event
.uloop
.fd
, IPPROTO_IPV6
, IPV6_DROP_MEMBERSHIP
,
106 &all_nodes
, sizeof(all_nodes
));
107 setsockopt(router_event
.uloop
.fd
, IPPROTO_IPV6
, IPV6_DROP_MEMBERSHIP
,
108 &all_routers
, sizeof(all_routers
));
112 trigger_router_advert(&iface
->timer_rs
);
114 void *mreq
= &all_routers
;
116 if (iface
->ra
== RELAYD_RELAY
&& iface
->master
) {
118 forward_router_solicitation(iface
);
119 } else if (iface
->ra
== RELAYD_SERVER
&& !iface
->master
) {
120 iface
->timer_rs
.cb
= trigger_router_advert
;
121 uloop_timeout_set(&iface
->timer_rs
, 1000);
124 if (iface
->ra
== RELAYD_RELAY
|| (iface
->ra
== RELAYD_SERVER
&& !iface
->master
))
125 setsockopt(router_event
.uloop
.fd
, IPPROTO_IPV6
,
126 IPV6_ADD_MEMBERSHIP
, mreq
, sizeof(all_nodes
));
132 // Signal handler to resend all RDs
133 static void sigusr1_refresh(_unused
int signal
)
135 struct interface
*iface
;
136 list_for_each_entry(iface
, &interfaces
, head
)
137 if (iface
->ra
== RELAYD_SERVER
&& !iface
->master
)
138 uloop_timeout_set(&iface
->timer_rs
, 1000);
141 static bool router_icmpv6_valid(struct sockaddr_in6
*source
, uint8_t *data
, size_t len
)
143 struct icmp6_hdr
*hdr
= (struct icmp6_hdr
*)data
;
144 struct icmpv6_opt
*opt
, *end
= (struct icmpv6_opt
*)&data
[len
];
146 /* Hoplimit is already checked in odhcpd_receive_packets */
147 if (len
< sizeof(*hdr
) || hdr
->icmp6_code
)
150 switch (hdr
->icmp6_type
) {
151 case ND_ROUTER_ADVERT
:
152 if (!IN6_IS_ADDR_LINKLOCAL(&source
->sin6_addr
))
155 opt
= (struct icmpv6_opt
*)((struct nd_router_advert
*)data
+ 1);
158 case ND_ROUTER_SOLICIT
:
159 opt
= (struct icmpv6_opt
*)((struct nd_router_solicit
*)data
+ 1);
166 icmpv6_for_each_option(opt
, opt
, end
)
167 if (opt
->type
== ND_OPT_SOURCE_LINKADDR
&&
168 IN6_IS_ADDR_UNSPECIFIED(&source
->sin6_addr
) &&
169 hdr
->icmp6_type
== ND_ROUTER_SOLICIT
)
172 // Check all options parsed successfully
177 // Detect whether a default route exists, also find the source prefixes
178 static bool parse_routes(struct odhcpd_ipaddr
*n
, ssize_t len
)
182 char line
[512], ifname
[16];
183 bool found_default
= false;
184 struct odhcpd_ipaddr p
= {IN6ADDR_ANY_INIT
, 0, 0, 0, 0};
185 while (fgets(line
, sizeof(line
), fp_route
)) {
187 if (sscanf(line
, "00000000000000000000000000000000 00 "
188 "%*s %*s %*s %*s %*s %*s %*s %15s", ifname
) &&
189 strcmp(ifname
, "lo")) {
190 found_default
= true;
191 } else if (sscanf(line
, "%8" SCNx32
"%8" SCNx32
"%*8" SCNx32
"%*8" SCNx32
" %hhx %*s "
192 "%*s 00000000000000000000000000000000 %*s %*s %*s %" SCNx32
" lo",
193 &p
.addr
.s6_addr32
[0], &p
.addr
.s6_addr32
[1], &p
.prefix
, &rflags
) &&
194 p
.prefix
> 0 && (rflags
& RTF_NONEXTHOP
) && (rflags
& RTF_REJECT
)) {
195 // Find source prefixes by scanning through unreachable-routes
196 p
.addr
.s6_addr32
[0] = htonl(p
.addr
.s6_addr32
[0]);
197 p
.addr
.s6_addr32
[1] = htonl(p
.addr
.s6_addr32
[1]);
199 for (ssize_t i
= 0; i
< len
; ++i
) {
200 if (n
[i
].prefix
<= 64 && n
[i
].prefix
>= p
.prefix
&&
201 !odhcpd_bmemcmp(&p
.addr
, &n
[i
].addr
, p
.prefix
)) {
202 n
[i
].dprefix
= p
.prefix
;
210 return found_default
;
213 // Router Advert server mode
214 static uint64_t send_router_advert(struct interface
*iface
, const struct in6_addr
*from
)
216 time_t now
= odhcpd_time();
217 int mtu
= odhcpd_get_interface_config(iface
->ifname
, "mtu");
218 int hlim
= odhcpd_get_interface_config(iface
->ifname
, "hop_limit");
224 struct nd_router_advert h
;
225 struct icmpv6_opt lladdr
;
226 struct nd_opt_mtu mtu
;
227 struct nd_opt_prefix_info prefix
[sizeof(iface
->ia_addr
) / sizeof(*iface
->ia_addr
)];
229 .h
= {{.icmp6_type
= ND_ROUTER_ADVERT
, .icmp6_code
= 0}, 0, 0},
230 .lladdr
= {ND_OPT_SOURCE_LINKADDR
, 1, {0}},
231 .mtu
= {ND_OPT_MTU
, 1, 0, htonl(mtu
)},
235 adv
.h
.nd_ra_curhoplimit
= hlim
;
238 adv
.h
.nd_ra_flags_reserved
= ND_RA_FLAG_OTHER
;
240 if (iface
->managed
>= RELAYD_MANAGED_MFLAG
)
241 adv
.h
.nd_ra_flags_reserved
|= ND_RA_FLAG_MANAGED
;
243 if (iface
->route_preference
< 0)
244 adv
.h
.nd_ra_flags_reserved
|= ND_RA_PREF_LOW
;
245 else if (iface
->route_preference
> 0)
246 adv
.h
.nd_ra_flags_reserved
|= ND_RA_PREF_HIGH
;
247 odhcpd_get_mac(iface
, adv
.lladdr
.data
);
249 // If not currently shutting down
250 struct odhcpd_ipaddr addrs
[8];
252 int64_t minvalid
= INT64_MAX
;
255 if (iface
->timer_rs
.cb
) {
256 ipcnt
= iface
->ia_addr_len
;
257 memcpy(addrs
, iface
->ia_addr
, ipcnt
* sizeof(*addrs
));
259 // Check default route
260 if (parse_routes(addrs
, ipcnt
))
261 adv
.h
.nd_ra_router_lifetime
= htons(1);
262 if (iface
->default_router
> 1)
263 adv
.h
.nd_ra_router_lifetime
= htons(iface
->default_router
);
266 // Construct Prefix Information options
269 struct in6_addr dns_pref
, *dns_addr
= &dns_pref
;
272 odhcpd_get_linklocal_interface_address(iface
->ifindex
, &dns_pref
);
274 for (ssize_t i
= 0; i
< ipcnt
; ++i
) {
275 struct odhcpd_ipaddr
*addr
= &addrs
[i
];
276 if (addr
->prefix
> 96 || addr
->valid
<= (uint32_t)now
)
277 continue; // Address not suitable
279 struct nd_opt_prefix_info
*p
= NULL
;
280 for (size_t i
= 0; i
< cnt
; ++i
) {
281 if (addr
->prefix
== adv
.prefix
[i
].nd_opt_pi_prefix_len
&&
282 !odhcpd_bmemcmp(&adv
.prefix
[i
].nd_opt_pi_prefix
,
283 &addr
->addr
, addr
->prefix
))
288 if (cnt
>= ARRAY_SIZE(adv
.prefix
))
291 p
= &adv
.prefix
[cnt
++];
294 if (addr
->preferred
> (uint32_t)now
&&
295 minvalid
> 1000LL * TIME_LEFT(addr
->valid
, now
))
296 minvalid
= 1000LL * TIME_LEFT(addr
->valid
, now
);
298 uint32_t this_lifetime
= TIME_LEFT(addr
->valid
, now
);
299 if (this_lifetime
> UINT16_MAX
)
300 this_lifetime
= UINT16_MAX
;
301 if (((addr
->addr
.s6_addr
[0] & 0xfe) != 0xfc || iface
->default_router
)
302 && adv
.h
.nd_ra_router_lifetime
303 && ntohs(adv
.h
.nd_ra_router_lifetime
) < this_lifetime
)
304 adv
.h
.nd_ra_router_lifetime
= htons(this_lifetime
);
306 odhcpd_bmemcpy(&p
->nd_opt_pi_prefix
, &addr
->addr
,
307 (iface
->ra_advrouter
) ? 128 : addr
->prefix
);
308 p
->nd_opt_pi_type
= ND_OPT_PREFIX_INFORMATION
;
309 p
->nd_opt_pi_len
= 4;
310 p
->nd_opt_pi_prefix_len
= (addr
->prefix
< 64) ? 64 : addr
->prefix
;
311 p
->nd_opt_pi_flags_reserved
= 0;
312 if (!iface
->ra_not_onlink
)
313 p
->nd_opt_pi_flags_reserved
|= ND_OPT_PI_FLAG_ONLINK
;
314 if (iface
->managed
< RELAYD_MANAGED_NO_AFLAG
&& addr
->prefix
<= 64)
315 p
->nd_opt_pi_flags_reserved
|= ND_OPT_PI_FLAG_AUTO
;
316 if (iface
->ra_advrouter
)
317 p
->nd_opt_pi_flags_reserved
|= ND_OPT_PI_FLAG_RADDR
;
318 p
->nd_opt_pi_valid_time
= htonl(TIME_LEFT(addr
->valid
, now
));
319 if (addr
->preferred
> (uint32_t)now
)
320 p
->nd_opt_pi_preferred_time
= htonl(TIME_LEFT(addr
->preferred
, now
));
321 else if (addr
->valid
- now
< 7200)
322 p
->nd_opt_pi_valid_time
= 0;
325 if (!iface
->default_router
&& adv
.h
.nd_ra_router_lifetime
== htons(1)) {
326 syslog(LOG_WARNING
, "A default route is present but there is no public prefix "
327 "on %s thus we don't announce a default route!", iface
->ifname
);
328 adv
.h
.nd_ra_router_lifetime
= 0;
332 if (iface
->dns_cnt
> 0) {
333 dns_addr
= iface
->dns
;
334 dns_cnt
= iface
->dns_cnt
;
337 if (!dns_addr
|| IN6_IS_ADDR_UNSPECIFIED(dns_addr
))
346 } dns
= {ND_OPT_RECURSIVE_DNS
, (1 + (2 * dns_cnt
)), 0, 0, 0};
350 // DNS Search options
351 uint8_t search_buf
[256], *search_domain
= iface
->search
;
352 size_t search_len
= iface
->search_len
, search_padded
= 0;
354 if (!search_domain
&& !res_init() && _res
.dnsrch
[0] && _res
.dnsrch
[0][0]) {
355 int len
= dn_comp(_res
.dnsrch
[0], search_buf
,
356 sizeof(search_buf
), NULL
, NULL
);
358 search_domain
= search_buf
;
364 search_padded
= ((search_len
+ 7) & (~7)) + 8;
373 } *search
= alloca(sizeof(*search
) + search_padded
);
375 search
->type
= ND_OPT_DNS_SEARCH
;
376 search
->len
= search_len
? ((sizeof(*search
) + search_padded
) / 8) : 0;
379 memcpy(search
->name
, search_domain
, search_len
);
380 memset(&search
->name
[search_len
], 0, search_padded
- search_len
);
383 size_t routes_cnt
= 0;
391 } routes
[RELAYD_MAX_PREFIXES
];
393 for (ssize_t i
= 0; i
< ipcnt
; ++i
) {
394 struct odhcpd_ipaddr
*addr
= &addrs
[i
];
395 if (addr
->dprefix
> 64 || addr
->dprefix
== 0 || addr
->valid
<= (uint32_t)now
||
396 (addr
->dprefix
== 64 && addr
->prefix
== 64)) {
397 continue; // Address not suitable
398 } else if (addr
->dprefix
> 32) {
399 addr
->addr
.s6_addr32
[1] &= htonl(~((1U << (64 - addr
->dprefix
)) - 1));
400 } else if (addr
->dprefix
<= 32) {
401 addr
->addr
.s6_addr32
[0] &= htonl(~((1U << (32 - addr
->dprefix
)) - 1));
402 addr
->addr
.s6_addr32
[1] = 0;
405 routes
[routes_cnt
].type
= ND_OPT_ROUTE_INFO
;
406 routes
[routes_cnt
].len
= sizeof(*routes
) / 8;
407 routes
[routes_cnt
].prefix
= addr
->dprefix
;
408 routes
[routes_cnt
].flags
= 0;
409 if (iface
->route_preference
< 0)
410 routes
[routes_cnt
].flags
|= ND_RA_PREF_LOW
;
411 else if (iface
->route_preference
> 0)
412 routes
[routes_cnt
].flags
|= ND_RA_PREF_HIGH
;
413 routes
[routes_cnt
].lifetime
= htonl(TIME_LEFT(addr
->valid
, now
));
414 routes
[routes_cnt
].addr
[0] = addr
->addr
.s6_addr32
[0];
415 routes
[routes_cnt
].addr
[1] = addr
->addr
.s6_addr32
[1];
416 routes
[routes_cnt
].addr
[2] = 0;
417 routes
[routes_cnt
].addr
[3] = 0;
422 // Calculate periodic transmit
424 uint32_t maxival
= iface
->ra_maxinterval
* 1000;
427 if (maxival
< 4000 || maxival
> MaxRtrAdvInterval
* 1000)
428 maxival
= MaxRtrAdvInterval
* 1000;
430 if (maxival
> minvalid
/ 3) {
431 maxival
= minvalid
/ 3;
437 minival
= (maxival
* 3) / 4;
439 search
->lifetime
= htonl(maxival
/ 100);
440 dns
.lifetime
= search
->lifetime
;
442 odhcpd_urandom(&msecs
, sizeof(msecs
));
443 msecs
= (labs(msecs
) % (maxival
- minival
)) + minival
;
445 struct icmpv6_opt adv_interval
= {
446 .type
= ND_OPT_RTR_ADV_INTERVAL
,
448 .data
= {0, 0, maxival
>> 24, maxival
>> 16, maxival
>> 8, maxival
}
451 struct iovec iov
[RA_IOV_LEN
] = {
452 {&adv
, (uint8_t*)&adv
.prefix
[cnt
] - (uint8_t*)&adv
},
453 {&routes
, routes_cnt
* sizeof(*routes
)},
454 {&dns
, (dns_cnt
) ? sizeof(dns
) : 0},
455 {dns_addr
, dns_cnt
* sizeof(*dns_addr
)},
456 {search
, search
->len
* 8},
457 {&adv_interval
, adv_interval
.len
* 8}};
458 struct sockaddr_in6 dest
= {AF_INET6
, 0, 0, ALL_IPV6_NODES
, 0};
460 if (from
&& !IN6_IS_ADDR_UNSPECIFIED(from
))
461 dest
.sin6_addr
= *from
;
463 odhcpd_send(router_event
.uloop
.fd
,
464 &dest
, iov
, ARRAY_SIZE(iov
), iface
);
470 static void trigger_router_advert(struct uloop_timeout
*event
)
472 struct interface
*iface
= container_of(event
, struct interface
, timer_rs
);
473 int msecs
= send_router_advert(iface
, NULL
);
475 // Rearm timer if not shut down
477 uloop_timeout_set(event
, msecs
);
481 // Event handler for incoming ICMPv6 packets
482 static void handle_icmpv6(void *addr
, void *data
, size_t len
,
483 struct interface
*iface
, _unused
void *dest
)
485 struct icmp6_hdr
*hdr
= data
;
486 struct sockaddr_in6
*from
= addr
;
488 if (!router_icmpv6_valid(addr
, data
, len
))
491 if ((iface
->ra
== RELAYD_SERVER
&& !iface
->master
)) { // Server mode
492 if (hdr
->icmp6_type
== ND_ROUTER_SOLICIT
)
493 send_router_advert(iface
, &from
->sin6_addr
);
494 } else if (iface
->ra
== RELAYD_RELAY
) { // Relay mode
495 if (hdr
->icmp6_type
== ND_ROUTER_ADVERT
&& iface
->master
)
496 forward_router_advertisement(data
, len
);
497 else if (hdr
->icmp6_type
== ND_ROUTER_SOLICIT
&& !iface
->master
)
498 forward_router_solicitation(odhcpd_get_master_interface());
503 // Forward router solicitation
504 static void forward_router_solicitation(const struct interface
*iface
)
509 struct icmp6_hdr rs
= {ND_ROUTER_SOLICIT
, 0, 0, {{0}}};
510 struct iovec iov
= {&rs
, sizeof(rs
)};
511 struct sockaddr_in6 all_routers
=
512 {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, iface
->ifindex
};
514 syslog(LOG_NOTICE
, "Sending RS to %s", iface
->ifname
);
515 odhcpd_send(router_event
.uloop
.fd
, &all_routers
, &iov
, 1, iface
);
519 // Handler for incoming router solicitations on slave interfaces
520 static void forward_router_advertisement(uint8_t *data
, size_t len
)
522 struct nd_router_advert
*adv
= (struct nd_router_advert
*)data
;
525 uint8_t *end
= data
+ len
;
526 uint8_t *mac_ptr
= NULL
;
527 struct in6_addr
*dns_ptr
= NULL
;
528 size_t dns_count
= 0;
530 struct icmpv6_opt
*opt
;
531 icmpv6_for_each_option(opt
, &adv
[1], end
) {
532 if (opt
->type
== ND_OPT_SOURCE_LINKADDR
) {
533 // Store address of source MAC-address
535 } else if (opt
->type
== ND_OPT_RECURSIVE_DNS
&& opt
->len
> 1) {
536 // Check if we have to rewrite DNS
537 dns_ptr
= (struct in6_addr
*)&opt
->data
[6];
538 dns_count
= (opt
->len
- 1) / 2;
542 syslog(LOG_NOTICE
, "Got a RA");
544 // Indicate a proxy, however we don't follow the rest of RFC 4389 yet
545 adv
->nd_ra_flags_reserved
|= ND_RA_FLAG_PROXY
;
547 // Forward advertisement to all slave interfaces
548 struct sockaddr_in6 all_nodes
= {AF_INET6
, 0, 0, ALL_IPV6_NODES
, 0};
549 struct iovec iov
= {data
, len
};
551 struct interface
*iface
;
552 list_for_each_entry(iface
, &interfaces
, head
) {
553 if (iface
->ra
!= RELAYD_RELAY
|| iface
->master
)
556 // Fixup source hardware address option
558 odhcpd_get_mac(iface
, mac_ptr
);
560 // If we have to rewrite DNS entries
561 if (iface
->always_rewrite_dns
&& dns_ptr
&& dns_count
> 0) {
562 const struct in6_addr
*rewrite
= iface
->dns
;
563 struct in6_addr addr
;
564 size_t rewrite_cnt
= iface
->dns_cnt
;
566 if (rewrite_cnt
== 0) {
567 if (odhcpd_get_linklocal_interface_address(iface
->ifindex
, &addr
))
568 continue; // Unable to comply
574 // Copy over any other addresses
575 for (size_t i
= 0; i
< dns_count
; ++i
) {
576 size_t j
= (i
< rewrite_cnt
) ? i
: rewrite_cnt
- 1;
577 dns_ptr
[i
] = rewrite
[j
];
581 odhcpd_send(router_event
.uloop
.fd
, &all_nodes
, &iov
, 1, iface
);