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
};
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 setsockopt(router_event
.uloop
.fd
, IPPROTO_IPV6
, IPV6_DROP_MEMBERSHIP
,
103 &all_nodes
, sizeof(all_nodes
));
104 setsockopt(router_event
.uloop
.fd
, IPPROTO_IPV6
, IPV6_DROP_MEMBERSHIP
,
105 &all_routers
, sizeof(all_routers
));
109 trigger_router_advert(&iface
->timer_rs
);
111 void *mreq
= &all_routers
;
113 if (iface
->ra
== RELAYD_RELAY
&& iface
->master
) {
115 forward_router_solicitation(iface
);
116 } else if (iface
->ra
== RELAYD_SERVER
&& !iface
->master
) {
117 iface
->timer_rs
.cb
= trigger_router_advert
;
118 uloop_timeout_set(&iface
->timer_rs
, 1000);
121 if (iface
->ra
== RELAYD_RELAY
|| (iface
->ra
== RELAYD_SERVER
&& !iface
->master
))
122 setsockopt(router_event
.uloop
.fd
, IPPROTO_IPV6
,
123 IPV6_ADD_MEMBERSHIP
, mreq
, sizeof(all_nodes
));
129 // Signal handler to resend all RDs
130 static void sigusr1_refresh(_unused
int signal
)
132 struct interface
*iface
;
133 list_for_each_entry(iface
, &interfaces
, head
)
134 if (iface
->ra
== RELAYD_SERVER
&& !iface
->master
)
135 uloop_timeout_set(&iface
->timer_rs
, 1000);
138 static bool router_icmpv6_valid(struct sockaddr_in6
*source
, uint8_t *data
, size_t len
)
140 struct icmp6_hdr
*hdr
= (struct icmp6_hdr
*)data
;
141 struct icmpv6_opt
*opt
, *end
= (struct icmpv6_opt
*)&data
[len
];
143 /* Hoplimit is already checked in odhcpd_receive_packets */
144 if (len
< sizeof(*hdr
) || hdr
->icmp6_code
)
147 switch (hdr
->icmp6_type
) {
148 case ND_ROUTER_ADVERT
:
149 if (!IN6_IS_ADDR_LINKLOCAL(&source
->sin6_addr
))
152 opt
= (struct icmpv6_opt
*)((struct nd_router_advert
*)data
+ 1);
155 case ND_ROUTER_SOLICIT
:
156 opt
= (struct icmpv6_opt
*)((struct nd_router_solicit
*)data
+ 1);
163 icmpv6_for_each_option(opt
, opt
, end
)
164 if (opt
->type
== ND_OPT_SOURCE_LINKADDR
&&
165 IN6_IS_ADDR_UNSPECIFIED(&source
->sin6_addr
) &&
166 hdr
->icmp6_type
== ND_ROUTER_SOLICIT
)
169 // Check all options parsed successfully
174 // Detect whether a default route exists, also find the source prefixes
175 static bool parse_routes(struct odhcpd_ipaddr
*n
, ssize_t len
)
179 char line
[512], ifname
[16];
180 bool found_default
= false;
181 struct odhcpd_ipaddr p
= {IN6ADDR_ANY_INIT
, 0, 0, 0, 0};
182 while (fgets(line
, sizeof(line
), fp_route
)) {
184 if (sscanf(line
, "00000000000000000000000000000000 00 "
185 "%*s %*s %*s %*s %*s %*s %*s %15s", ifname
) &&
186 strcmp(ifname
, "lo")) {
187 found_default
= true;
188 } else if (sscanf(line
, "%8" SCNx32
"%8" SCNx32
"%*8" SCNx32
"%*8" SCNx32
" %hhx %*s "
189 "%*s 00000000000000000000000000000000 %*s %*s %*s %" SCNx32
" lo",
190 &p
.addr
.s6_addr32
[0], &p
.addr
.s6_addr32
[1], &p
.prefix
, &rflags
) &&
191 p
.prefix
> 0 && (rflags
& RTF_NONEXTHOP
) && (rflags
& RTF_REJECT
)) {
192 // Find source prefixes by scanning through unreachable-routes
193 p
.addr
.s6_addr32
[0] = htonl(p
.addr
.s6_addr32
[0]);
194 p
.addr
.s6_addr32
[1] = htonl(p
.addr
.s6_addr32
[1]);
196 for (ssize_t i
= 0; i
< len
; ++i
) {
197 if (n
[i
].prefix
<= 64 && n
[i
].prefix
>= p
.prefix
&&
198 !odhcpd_bmemcmp(&p
.addr
, &n
[i
].addr
, p
.prefix
)) {
199 n
[i
].dprefix
= p
.prefix
;
207 return found_default
;
210 // Router Advert server mode
211 static uint64_t send_router_advert(struct interface
*iface
, const struct in6_addr
*from
)
213 time_t now
= odhcpd_time();
214 int mtu
= odhcpd_get_interface_config(iface
->ifname
, "mtu");
215 int hlim
= odhcpd_get_interface_config(iface
->ifname
, "hop_limit");
221 struct nd_router_advert h
;
222 struct icmpv6_opt lladdr
;
223 struct nd_opt_mtu mtu
;
224 struct nd_opt_prefix_info prefix
[sizeof(iface
->ia_addr
) / sizeof(*iface
->ia_addr
)];
226 .h
= {{.icmp6_type
= ND_ROUTER_ADVERT
, .icmp6_code
= 0}, 0, 0},
227 .lladdr
= {ND_OPT_SOURCE_LINKADDR
, 1, {0}},
228 .mtu
= {ND_OPT_MTU
, 1, 0, htonl(mtu
)},
232 adv
.h
.nd_ra_curhoplimit
= hlim
;
235 adv
.h
.nd_ra_flags_reserved
= ND_RA_FLAG_OTHER
;
237 if (iface
->managed
>= RELAYD_MANAGED_MFLAG
)
238 adv
.h
.nd_ra_flags_reserved
|= ND_RA_FLAG_MANAGED
;
240 if (iface
->route_preference
< 0)
241 adv
.h
.nd_ra_flags_reserved
|= ND_RA_PREF_LOW
;
242 else if (iface
->route_preference
> 0)
243 adv
.h
.nd_ra_flags_reserved
|= ND_RA_PREF_HIGH
;
244 odhcpd_get_mac(iface
, adv
.lladdr
.data
);
246 // If not currently shutting down
247 struct odhcpd_ipaddr addrs
[8];
249 int64_t minvalid
= INT64_MAX
;
252 if (iface
->timer_rs
.cb
) {
253 ipcnt
= iface
->ia_addr_len
;
254 memcpy(addrs
, iface
->ia_addr
, ipcnt
* sizeof(*addrs
));
256 // Check default route
257 if (parse_routes(addrs
, ipcnt
))
258 adv
.h
.nd_ra_router_lifetime
= htons(1);
259 if (iface
->default_router
> 1)
260 adv
.h
.nd_ra_router_lifetime
= htons(iface
->default_router
);
263 // Construct Prefix Information options
266 struct in6_addr dns_pref
, *dns_addr
= &dns_pref
;
269 odhcpd_get_linklocal_interface_address(iface
->ifindex
, &dns_pref
);
271 for (ssize_t i
= 0; i
< ipcnt
; ++i
) {
272 struct odhcpd_ipaddr
*addr
= &addrs
[i
];
273 if (addr
->prefix
> 96 || addr
->valid
<= (uint32_t)now
)
274 continue; // Address not suitable
276 struct nd_opt_prefix_info
*p
= NULL
;
277 for (size_t i
= 0; i
< cnt
; ++i
) {
278 if (addr
->prefix
== adv
.prefix
[i
].nd_opt_pi_prefix_len
&&
279 !odhcpd_bmemcmp(&adv
.prefix
[i
].nd_opt_pi_prefix
,
280 &addr
->addr
, addr
->prefix
))
285 if (cnt
>= ARRAY_SIZE(adv
.prefix
))
288 p
= &adv
.prefix
[cnt
++];
291 if (addr
->preferred
> (uint32_t)now
&&
292 minvalid
> 1000LL * TIME_LEFT(addr
->valid
, now
))
293 minvalid
= 1000LL * TIME_LEFT(addr
->valid
, now
);
295 if (((addr
->addr
.s6_addr
[0] & 0xfe) != 0xfc || iface
->default_router
)
296 && adv
.h
.nd_ra_router_lifetime
297 && ntohs(adv
.h
.nd_ra_router_lifetime
) < TIME_LEFT(addr
->valid
, now
))
298 adv
.h
.nd_ra_router_lifetime
= htons(TIME_LEFT(addr
->valid
, now
));
300 odhcpd_bmemcpy(&p
->nd_opt_pi_prefix
, &addr
->addr
,
301 (iface
->ra_advrouter
) ? 128 : addr
->prefix
);
302 p
->nd_opt_pi_type
= ND_OPT_PREFIX_INFORMATION
;
303 p
->nd_opt_pi_len
= 4;
304 p
->nd_opt_pi_prefix_len
= (addr
->prefix
< 64) ? 64 : addr
->prefix
;
305 p
->nd_opt_pi_flags_reserved
= 0;
306 if (!iface
->ra_not_onlink
)
307 p
->nd_opt_pi_flags_reserved
|= ND_OPT_PI_FLAG_ONLINK
;
308 if (iface
->managed
< RELAYD_MANAGED_NO_AFLAG
&& addr
->prefix
<= 64)
309 p
->nd_opt_pi_flags_reserved
|= ND_OPT_PI_FLAG_AUTO
;
310 if (iface
->ra_advrouter
)
311 p
->nd_opt_pi_flags_reserved
|= ND_OPT_PI_FLAG_RADDR
;
312 p
->nd_opt_pi_valid_time
= htonl(TIME_LEFT(addr
->valid
, now
));
313 if (addr
->preferred
> (uint32_t)now
)
314 p
->nd_opt_pi_preferred_time
= htonl(TIME_LEFT(addr
->preferred
, now
));
315 else if (addr
->valid
- now
< 7200)
316 p
->nd_opt_pi_valid_time
= 0;
319 if (!iface
->default_router
&& adv
.h
.nd_ra_router_lifetime
== htons(1)) {
320 syslog(LOG_WARNING
, "A default route is present but there is no public prefix "
321 "on %s thus we don't announce a default route!", iface
->ifname
);
322 adv
.h
.nd_ra_router_lifetime
= 0;
326 if (iface
->dns_cnt
> 0) {
327 dns_addr
= iface
->dns
;
328 dns_cnt
= iface
->dns_cnt
;
331 if (!dns_addr
|| IN6_IS_ADDR_UNSPECIFIED(dns_addr
))
340 } dns
= {ND_OPT_RECURSIVE_DNS
, (1 + (2 * dns_cnt
)), 0, 0, 0};
344 // DNS Search options
345 uint8_t search_buf
[256], *search_domain
= iface
->search
;
346 size_t search_len
= iface
->search_len
, search_padded
= 0;
348 if (!search_domain
&& !res_init() && _res
.dnsrch
[0] && _res
.dnsrch
[0][0]) {
349 int len
= dn_comp(_res
.dnsrch
[0], search_buf
,
350 sizeof(search_buf
), NULL
, NULL
);
352 search_domain
= search_buf
;
358 search_padded
= ((search_len
+ 7) & (~7)) + 8;
367 } *search
= alloca(sizeof(*search
) + search_padded
);
369 search
->type
= ND_OPT_DNS_SEARCH
;
370 search
->len
= search_len
? ((sizeof(*search
) + search_padded
) / 8) : 0;
373 memcpy(search
->name
, search_domain
, search_len
);
374 memset(&search
->name
[search_len
], 0, search_padded
- search_len
);
377 size_t routes_cnt
= 0;
385 } routes
[RELAYD_MAX_PREFIXES
];
387 for (ssize_t i
= 0; i
< ipcnt
; ++i
) {
388 struct odhcpd_ipaddr
*addr
= &addrs
[i
];
389 if (addr
->dprefix
> 64 || addr
->dprefix
== 0 || addr
->valid
<= (uint32_t)now
||
390 (addr
->dprefix
== 64 && addr
->prefix
== 64)) {
391 continue; // Address not suitable
392 } else if (addr
->dprefix
> 32) {
393 addr
->addr
.s6_addr32
[1] &= htonl(~((1U << (64 - addr
->dprefix
)) - 1));
394 } else if (addr
->dprefix
<= 32) {
395 addr
->addr
.s6_addr32
[0] &= htonl(~((1U << (32 - addr
->dprefix
)) - 1));
396 addr
->addr
.s6_addr32
[1] = 0;
399 routes
[routes_cnt
].type
= ND_OPT_ROUTE_INFO
;
400 routes
[routes_cnt
].len
= sizeof(*routes
) / 8;
401 routes
[routes_cnt
].prefix
= addr
->dprefix
;
402 routes
[routes_cnt
].flags
= 0;
403 if (iface
->route_preference
< 0)
404 routes
[routes_cnt
].flags
|= ND_RA_PREF_LOW
;
405 else if (iface
->route_preference
> 0)
406 routes
[routes_cnt
].flags
|= ND_RA_PREF_HIGH
;
407 routes
[routes_cnt
].lifetime
= htonl(TIME_LEFT(addr
->valid
, now
));
408 routes
[routes_cnt
].addr
[0] = addr
->addr
.s6_addr32
[0];
409 routes
[routes_cnt
].addr
[1] = addr
->addr
.s6_addr32
[1];
410 routes
[routes_cnt
].addr
[2] = 0;
411 routes
[routes_cnt
].addr
[3] = 0;
416 // Calculate periodic transmit
418 uint32_t maxival
= iface
->ra_maxinterval
* 1000;
421 if (maxival
< 4000 || maxival
> MaxRtrAdvInterval
* 1000)
422 maxival
= MaxRtrAdvInterval
* 1000;
424 if (maxival
> minvalid
/ 3) {
425 maxival
= minvalid
/ 3;
431 minival
= (maxival
* 3) / 4;
433 search
->lifetime
= maxival
/ 100;
434 dns
.lifetime
= search
->lifetime
;
436 odhcpd_urandom(&msecs
, sizeof(msecs
));
437 msecs
= (labs(msecs
) % (maxival
- minival
)) + minival
;
439 struct icmpv6_opt adv_interval
= {
440 .type
= ND_OPT_RTR_ADV_INTERVAL
,
442 .data
= {0, 0, maxival
>> 24, maxival
>> 16, maxival
>> 8, maxival
}
445 struct iovec iov
[RA_IOV_LEN
] = {
446 {&adv
, (uint8_t*)&adv
.prefix
[cnt
] - (uint8_t*)&adv
},
447 {&routes
, routes_cnt
* sizeof(*routes
)},
448 {&dns
, (dns_cnt
) ? sizeof(dns
) : 0},
449 {dns_addr
, dns_cnt
* sizeof(*dns_addr
)},
450 {search
, search
->len
* 8},
451 {&adv_interval
, adv_interval
.len
* 8}};
452 struct sockaddr_in6 dest
= {AF_INET6
, 0, 0, ALL_IPV6_NODES
, 0};
454 if (from
&& !IN6_IS_ADDR_UNSPECIFIED(from
))
455 dest
.sin6_addr
= *from
;
457 odhcpd_send(router_event
.uloop
.fd
,
458 &dest
, iov
, ARRAY_SIZE(iov
), iface
);
464 static void trigger_router_advert(struct uloop_timeout
*event
)
466 struct interface
*iface
= container_of(event
, struct interface
, timer_rs
);
467 int msecs
= send_router_advert(iface
, NULL
);
469 // Rearm timer if not shut down
471 uloop_timeout_set(event
, msecs
);
475 // Event handler for incoming ICMPv6 packets
476 static void handle_icmpv6(void *addr
, void *data
, size_t len
,
477 struct interface
*iface
, _unused
void *dest
)
479 struct icmp6_hdr
*hdr
= data
;
480 struct sockaddr_in6
*from
= addr
;
482 if (!router_icmpv6_valid(addr
, data
, len
))
485 if ((iface
->ra
== RELAYD_SERVER
&& !iface
->master
)) { // Server mode
486 if (hdr
->icmp6_type
== ND_ROUTER_SOLICIT
)
487 send_router_advert(iface
, &from
->sin6_addr
);
488 } else if (iface
->ra
== RELAYD_RELAY
) { // Relay mode
489 if (hdr
->icmp6_type
== ND_ROUTER_ADVERT
&& iface
->master
)
490 forward_router_advertisement(data
, len
);
491 else if (hdr
->icmp6_type
== ND_ROUTER_SOLICIT
&& !iface
->master
)
492 forward_router_solicitation(odhcpd_get_master_interface());
497 // Forward router solicitation
498 static void forward_router_solicitation(const struct interface
*iface
)
503 struct icmp6_hdr rs
= {ND_ROUTER_SOLICIT
, 0, 0, {{0}}};
504 struct iovec iov
= {&rs
, sizeof(rs
)};
505 struct sockaddr_in6 all_routers
=
506 {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, iface
->ifindex
};
508 syslog(LOG_NOTICE
, "Sending RS to %s", iface
->ifname
);
509 odhcpd_send(router_event
.uloop
.fd
, &all_routers
, &iov
, 1, iface
);
513 // Handler for incoming router solicitations on slave interfaces
514 static void forward_router_advertisement(uint8_t *data
, size_t len
)
516 struct nd_router_advert
*adv
= (struct nd_router_advert
*)data
;
519 uint8_t *end
= data
+ len
;
520 uint8_t *mac_ptr
= NULL
;
521 struct in6_addr
*dns_ptr
= NULL
;
522 size_t dns_count
= 0;
524 struct icmpv6_opt
*opt
;
525 icmpv6_for_each_option(opt
, &adv
[1], end
) {
526 if (opt
->type
== ND_OPT_SOURCE_LINKADDR
) {
527 // Store address of source MAC-address
529 } else if (opt
->type
== ND_OPT_RECURSIVE_DNS
&& opt
->len
> 1) {
530 // Check if we have to rewrite DNS
531 dns_ptr
= (struct in6_addr
*)&opt
->data
[6];
532 dns_count
= (opt
->len
- 1) / 2;
536 syslog(LOG_NOTICE
, "Got a RA");
538 // Indicate a proxy, however we don't follow the rest of RFC 4389 yet
539 adv
->nd_ra_flags_reserved
|= ND_RA_FLAG_PROXY
;
541 // Forward advertisement to all slave interfaces
542 struct sockaddr_in6 all_nodes
= {AF_INET6
, 0, 0, ALL_IPV6_NODES
, 0};
543 struct iovec iov
= {data
, len
};
545 struct interface
*iface
;
546 list_for_each_entry(iface
, &interfaces
, head
) {
547 if (iface
->ra
!= RELAYD_RELAY
|| iface
->master
)
550 // Fixup source hardware address option
552 odhcpd_get_mac(iface
, mac_ptr
);
554 // If we have to rewrite DNS entries
555 if (iface
->always_rewrite_dns
&& dns_ptr
&& dns_count
> 0) {
556 const struct in6_addr
*rewrite
= iface
->dns
;
557 struct in6_addr addr
;
558 size_t rewrite_cnt
= iface
->dns_cnt
;
560 if (rewrite_cnt
== 0) {
561 if (odhcpd_get_linklocal_interface_address(iface
->ifindex
, &addr
))
562 continue; // Unable to comply
568 // Copy over any other addresses
569 for (size_t i
= 0; i
< dns_count
; ++i
) {
570 size_t j
= (i
< rewrite_cnt
) ? i
: rewrite_cnt
- 1;
571 dns_ptr
[i
] = rewrite
[j
];
575 odhcpd_send(router_event
.uloop
.fd
, &all_nodes
, &iov
, 1, iface
);