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
);
34 static void send_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
;
45 int sock
= socket(AF_INET6
, SOCK_RAW
| SOCK_CLOEXEC
, IPPROTO_ICMPV6
);
46 if (sock
< 0 && errno
!= EAFNOSUPPORT
) {
47 syslog(LOG_ERR
, "Failed to open RAW-socket: %s", strerror(errno
));
51 // Let the kernel compute our checksums
53 setsockopt(sock
, IPPROTO_RAW
, IPV6_CHECKSUM
, &val
, sizeof(val
));
55 // This is required by RFC 4861
57 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
));
58 setsockopt(sock
, IPPROTO_IPV6
, IPV6_UNICAST_HOPS
, &val
, sizeof(val
));
60 // We need to know the source interface
62 setsockopt(sock
, IPPROTO_IPV6
, IPV6_RECVPKTINFO
, &val
, sizeof(val
));
63 setsockopt(sock
, IPPROTO_IPV6
, IPV6_RECVHOPLIMIT
, &val
, sizeof(val
));
67 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_LOOP
, &val
, sizeof(val
));
69 // Filter ICMPv6 package types
70 struct icmp6_filter filt
;
71 ICMP6_FILTER_SETBLOCKALL(&filt
);
72 ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT
, &filt
);
73 ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT
, &filt
);
74 setsockopt(sock
, IPPROTO_ICMPV6
, ICMP6_FILTER
, &filt
, sizeof(filt
));
77 router_event
.uloop
.fd
= sock
;
78 odhcpd_register(&router_event
);
80 if (!(fp_route
= fopen("/proc/net/ipv6_route", "r")))
81 syslog(LOG_ERR
, "Failed to open routing table: %s",
84 signal(SIGUSR1
, sigusr1_refresh
);
89 int setup_router_interface(struct interface
*iface
, bool enable
)
91 struct ipv6_mreq all_nodes
= {ALL_IPV6_NODES
, iface
->ifindex
};
92 struct ipv6_mreq all_routers
= {ALL_IPV6_ROUTERS
, iface
->ifindex
};
94 uloop_timeout_cancel(&iface
->timer_rs
);
95 iface
->timer_rs
.cb
= NULL
;
97 setsockopt(router_event
.uloop
.fd
, IPPROTO_IPV6
, IPV6_DROP_MEMBERSHIP
,
98 &all_nodes
, sizeof(all_nodes
));
99 setsockopt(router_event
.uloop
.fd
, IPPROTO_IPV6
, IPV6_DROP_MEMBERSHIP
,
100 &all_routers
, sizeof(all_routers
));
104 send_router_advert(&iface
->timer_rs
);
106 void *mreq
= &all_routers
;
108 if (iface
->ra
== RELAYD_RELAY
&& iface
->master
) {
110 forward_router_solicitation(iface
);
111 } else if (iface
->ra
== RELAYD_SERVER
&& !iface
->master
) {
112 iface
->timer_rs
.cb
= send_router_advert
;
113 send_router_advert(&iface
->timer_rs
);
116 if (iface
->ra
== RELAYD_RELAY
|| (iface
->ra
== RELAYD_SERVER
&& !iface
->master
))
117 setsockopt(router_event
.uloop
.fd
, IPPROTO_IPV6
,
118 IPV6_ADD_MEMBERSHIP
, mreq
, sizeof(all_nodes
));
124 // Signal handler to resend all RDs
125 static void sigusr1_refresh(_unused
int signal
)
127 struct interface
*iface
;
128 list_for_each_entry(iface
, &interfaces
, head
)
129 if (iface
->ra
== RELAYD_SERVER
&& !iface
->master
)
130 uloop_timeout_set(&iface
->timer_rs
, 1000);
133 static bool router_icmpv6_valid(struct sockaddr_in6
*source
, uint8_t *data
, size_t len
)
135 struct icmp6_hdr
*hdr
= (struct icmp6_hdr
*)data
;
136 struct icmpv6_opt
*opt
, *end
= (struct icmpv6_opt
*)&data
[len
];
138 /* Hoplimit is already checked in odhcpd_receive_packets */
139 if (len
< sizeof(*hdr
) || hdr
->icmp6_code
)
142 switch (hdr
->icmp6_type
) {
143 case ND_ROUTER_ADVERT
:
144 if (!IN6_IS_ADDR_LINKLOCAL(&source
->sin6_addr
))
147 opt
= (struct icmpv6_opt
*)((struct nd_router_advert
*)data
+ 1);
150 case ND_ROUTER_SOLICIT
:
151 opt
= (struct icmpv6_opt
*)((struct nd_router_solicit
*)data
+ 1);
158 icmpv6_for_each_option(opt
, opt
, end
)
159 if (opt
->type
== ND_OPT_SOURCE_LINKADDR
&&
160 IN6_IS_ADDR_UNSPECIFIED(&source
->sin6_addr
) &&
161 hdr
->icmp6_type
== ND_ROUTER_SOLICIT
)
164 // Check all options parsed successfully
168 // Event handler for incoming ICMPv6 packets
169 static void handle_icmpv6(void *addr
, void *data
, size_t len
,
170 struct interface
*iface
)
172 struct icmp6_hdr
*hdr
= data
;
174 if (!router_icmpv6_valid(addr
, data
, len
))
177 if ((iface
->ra
== RELAYD_SERVER
&& !iface
->master
)) { // Server mode
178 if (hdr
->icmp6_type
== ND_ROUTER_SOLICIT
)
179 send_router_advert(&iface
->timer_rs
);
180 } else if (iface
->ra
== RELAYD_RELAY
) { // Relay mode
181 if (hdr
->icmp6_type
== ND_ROUTER_ADVERT
&& iface
->master
)
182 forward_router_advertisement(data
, len
);
183 else if (hdr
->icmp6_type
== ND_ROUTER_SOLICIT
&& !iface
->master
)
184 forward_router_solicitation(odhcpd_get_master_interface());
189 static bool match_route(const struct odhcpd_ipaddr
*n
, const struct in6_addr
*addr
)
192 return ntohl(n
->addr
.s6_addr32
[0]) >> (32 - n
->prefix
) ==
193 ntohl(addr
->s6_addr32
[0]) >> (32 - n
->prefix
);
195 if (n
->addr
.s6_addr32
[0] != addr
->s6_addr32
[0])
198 return ntohl(n
->addr
.s6_addr32
[1]) >> (64 - n
->prefix
) ==
199 ntohl(addr
->s6_addr32
[1]) >> (64 - n
->prefix
);
203 // Detect whether a default route exists, also find the source prefixes
204 static bool parse_routes(struct odhcpd_ipaddr
*n
, ssize_t len
)
208 char line
[512], ifname
[16];
209 bool found_default
= false;
210 struct odhcpd_ipaddr p
= {IN6ADDR_ANY_INIT
, 0, false, 0, 0, 0};
211 while (fgets(line
, sizeof(line
), fp_route
)) {
213 if (sscanf(line
, "00000000000000000000000000000000 00 "
214 "%*s %*s %*s %*s %*s %*s %*s %15s", ifname
) &&
215 strcmp(ifname
, "lo")) {
216 found_default
= true;
217 } else if (sscanf(line
, "%8" SCNx32
"%8" SCNx32
"%*8" SCNx32
"%*8" SCNx32
" %hhx %*s "
218 "%*s 00000000000000000000000000000000 %*s %*s %*s %" SCNx32
" lo",
219 &p
.addr
.s6_addr32
[0], &p
.addr
.s6_addr32
[1], &p
.prefix
, &rflags
) &&
220 p
.prefix
> 0 && (rflags
& RTF_NONEXTHOP
) && (rflags
& RTF_REJECT
)) {
221 // Find source prefixes by scanning through unreachable-routes
222 p
.addr
.s6_addr32
[0] = htonl(p
.addr
.s6_addr32
[0]);
223 p
.addr
.s6_addr32
[1] = htonl(p
.addr
.s6_addr32
[1]);
225 for (ssize_t i
= 0; i
< len
; ++i
) {
226 if (n
[i
].prefix
<= 64 && n
[i
].prefix
>= p
.prefix
&&
227 match_route(&p
, &n
[i
].addr
)) {
228 n
[i
].prefix
= p
.prefix
;
236 return found_default
;
240 // Router Advert server mode
241 static void send_router_advert(struct uloop_timeout
*event
)
243 struct interface
*iface
=
244 container_of(event
, struct interface
, timer_rs
);
246 int mtu
= odhcpd_get_interface_mtu(iface
->ifname
);
251 struct nd_router_advert h
;
252 struct icmpv6_opt lladdr
;
253 struct nd_opt_mtu mtu
;
254 struct nd_opt_prefix_info prefix
[RELAYD_MAX_PREFIXES
];
256 .h
= {{.icmp6_type
= ND_ROUTER_ADVERT
, .icmp6_code
= 0}, 0, 0},
257 .lladdr
= {ND_OPT_SOURCE_LINKADDR
, 1, {0}},
258 .mtu
= {ND_OPT_MTU
, 1, 0, htonl(mtu
)},
262 adv
.h
.nd_ra_flags_reserved
= ND_RA_FLAG_OTHER
;
264 if (iface
->managed
>= RELAYD_MANAGED_MFLAG
)
265 adv
.h
.nd_ra_flags_reserved
|= ND_RA_FLAG_MANAGED
;
267 if (iface
->route_preference
< 0)
268 adv
.h
.nd_ra_flags_reserved
|= ND_RA_PREF_LOW
;
269 else if (iface
->route_preference
> 0)
270 adv
.h
.nd_ra_flags_reserved
|= ND_RA_PREF_HIGH
;
271 odhcpd_get_mac(iface
, adv
.lladdr
.data
);
273 // If not currently shutting down
274 struct odhcpd_ipaddr addrs
[RELAYD_MAX_PREFIXES
];
276 uint64_t maxpreferred
= 0;
280 ipcnt
= odhcpd_get_interface_addresses(iface
->ifindex
,
281 addrs
, ARRAY_SIZE(addrs
));
283 // Check default route
284 if (parse_routes(addrs
, ipcnt
) || iface
->default_router
> 1)
285 adv
.h
.nd_ra_router_lifetime
=
286 htons(3 * MaxRtrAdvInterval
);
289 // Construct Prefix Information options
290 bool have_public
= false;
293 struct in6_addr
*dns_addr
= NULL
;
294 uint32_t dns_time
= 0;
297 for (ssize_t i
= 0; i
< ipcnt
; ++i
) {
298 struct odhcpd_ipaddr
*addr
= &addrs
[i
];
299 if (addr
->prefix
> 64 || addr
->has_class
)
300 continue; // Address not suitable
302 if (addr
->preferred
> MaxPreferredTime
)
303 addr
->preferred
= MaxPreferredTime
;
305 if (addr
->valid
> MaxValidTime
)
306 addr
->valid
= MaxValidTime
;
308 struct nd_opt_prefix_info
*p
= NULL
;
309 for (size_t i
= 0; i
< cnt
; ++i
) {
310 if (!memcmp(&adv
.prefix
[i
].nd_opt_pi_prefix
,
316 if (cnt
>= ARRAY_SIZE(adv
.prefix
))
319 p
= &adv
.prefix
[cnt
++];
322 if ((addr
->addr
.s6_addr
[0] & 0xfe) != 0xfc && addr
->preferred
> 0) {
325 if (maxpreferred
< 1000 * addr
->preferred
)
326 maxpreferred
= 1000 * addr
->preferred
;
329 memcpy(&p
->nd_opt_pi_prefix
, &addr
->addr
, 8);
330 p
->nd_opt_pi_type
= ND_OPT_PREFIX_INFORMATION
;
331 p
->nd_opt_pi_len
= 4;
332 p
->nd_opt_pi_prefix_len
= 64;
333 p
->nd_opt_pi_flags_reserved
= 0;
334 if (!iface
->ra_not_onlink
)
335 p
->nd_opt_pi_flags_reserved
|= ND_OPT_PI_FLAG_ONLINK
;
336 if (iface
->managed
< RELAYD_MANAGED_NO_AFLAG
)
337 p
->nd_opt_pi_flags_reserved
|= ND_OPT_PI_FLAG_AUTO
;
338 p
->nd_opt_pi_valid_time
= htonl(addr
->valid
);
339 p
->nd_opt_pi_preferred_time
= htonl(addr
->preferred
);
341 if (addr
->preferred
> dns_time
) {
342 dns_time
= addr
->preferred
;
343 dns_addr
= &addr
->addr
;
347 if (!have_public
&& !iface
->default_router
&& adv
.h
.nd_ra_router_lifetime
) {
348 syslog(LOG_WARNING
, "A default route is present but there is no public prefix "
349 "on %s thus we don't announce a default route!", iface
->ifname
);
350 adv
.h
.nd_ra_router_lifetime
= 0;
354 if (iface
->dns_cnt
> 0) {
355 dns_addr
= iface
->dns
;
356 dns_cnt
= iface
->dns_cnt
;
357 dns_time
= 2 * MaxRtrAdvInterval
;
369 } dns
= {ND_OPT_RECURSIVE_DNS
, (1 + (2 * dns_cnt
)), 0, 0, htonl(dns_time
)};
373 // DNS Search options
374 uint8_t search_buf
[256], *search_domain
= iface
->search
;
375 size_t search_len
= iface
->search_len
, search_padded
= 0;
377 if (!search_domain
&& !res_init() && _res
.dnsrch
[0] && _res
.dnsrch
[0][0]) {
378 int len
= dn_comp(_res
.dnsrch
[0], search_buf
,
379 sizeof(search_buf
), NULL
, NULL
);
381 search_domain
= search_buf
;
387 search_padded
= ((search_len
+ 7) & (~7)) + 8;
396 } *search
= alloca(sizeof(*search
) + search_padded
);
399 syslog(LOG_ERR
, "Alloca failed for dns search on interface %s", iface
->ifname
);
402 search
->type
= ND_OPT_DNS_SEARCH
;
403 search
->len
= search_len
? ((sizeof(*search
) + search_padded
) / 8) : 0;
406 search
->lifetime
= htonl(2 * MaxRtrAdvInterval
);;
407 memcpy(search
->name
, search_domain
, search_len
);
408 memset(&search
->name
[search_len
], 0, search_padded
- search_len
);
411 size_t routes_cnt
= 0;
419 } routes
[RELAYD_MAX_PREFIXES
];
421 for (ssize_t i
= 0; i
< ipcnt
; ++i
) {
422 struct odhcpd_ipaddr
*addr
= &addrs
[i
];
423 if (addr
->prefix
> 64 || addr
->prefix
== 0) {
424 continue; // Address not suitable
425 } else if (addr
->prefix
> 32) {
426 addr
->addr
.s6_addr32
[1] &= htonl(~((1U << (64 - addr
->prefix
)) - 1));
427 } else if (addr
->prefix
<= 32) {
428 addr
->addr
.s6_addr32
[0] &= htonl(~((1U << (32 - addr
->prefix
)) - 1));
429 addr
->addr
.s6_addr32
[1] = 0;
432 routes
[routes_cnt
].type
= ND_OPT_ROUTE_INFO
;
433 routes
[routes_cnt
].len
= sizeof(*routes
) / 8;
434 routes
[routes_cnt
].prefix
= addr
->prefix
;
435 routes
[routes_cnt
].flags
= 0;
436 if (iface
->route_preference
< 0)
437 routes
[routes_cnt
].flags
|= ND_RA_PREF_LOW
;
438 else if (iface
->route_preference
> 0)
439 routes
[routes_cnt
].flags
|= ND_RA_PREF_HIGH
;
440 routes
[routes_cnt
].lifetime
= htonl(addr
->valid
);
441 routes
[routes_cnt
].addr
[0] = addr
->addr
.s6_addr32
[0];
442 routes
[routes_cnt
].addr
[1] = addr
->addr
.s6_addr32
[1];
443 routes
[routes_cnt
].addr
[2] = addr
->addr
.s6_addr32
[2];
444 routes
[routes_cnt
].addr
[3] = addr
->addr
.s6_addr32
[3];
450 struct iovec iov
[] = {{&adv
, (uint8_t*)&adv
.prefix
[cnt
] - (uint8_t*)&adv
},
451 {&routes
, routes_cnt
* sizeof(*routes
)},
452 {&dns
, (dns_cnt
) ? sizeof(dns
) : 0},
453 {dns_addr
, dns_cnt
* sizeof(*dns_addr
)},
454 {search
, search
->len
* 8}};
455 struct sockaddr_in6 all_nodes
= {AF_INET6
, 0, 0, ALL_IPV6_NODES
, 0};
456 odhcpd_send(router_event
.uloop
.fd
,
457 &all_nodes
, iov
, ARRAY_SIZE(iov
), iface
);
459 // Rearm timer if not shut down
461 uint32_t maxinterval
= MaxRtrAdvInterval
* 1000;
462 uint32_t mininterval
= MinRtrAdvInterval
* 1000;
464 if (maxpreferred
> 0 && maxinterval
> maxpreferred
/ 2) {
465 maxinterval
= maxpreferred
/ 2;
466 if (maxinterval
< 4000)
469 if (maxinterval
>= 9000)
470 mininterval
= maxinterval
/ 3;
472 mininterval
= (maxinterval
* 3) / 4;
476 odhcpd_urandom(&msecs
, sizeof(msecs
));
477 msecs
= (labs(msecs
) % (maxinterval
- mininterval
)) + mininterval
;
478 uloop_timeout_set(&iface
->timer_rs
, msecs
);
483 // Forward router solicitation
484 static void forward_router_solicitation(const struct interface
*iface
)
489 struct icmp6_hdr rs
= {ND_ROUTER_SOLICIT
, 0, 0, {{0}}};
490 struct iovec iov
= {&rs
, sizeof(rs
)};
491 struct sockaddr_in6 all_routers
=
492 {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, iface
->ifindex
};
494 syslog(LOG_NOTICE
, "Sending RS to %s", iface
->ifname
);
495 odhcpd_send(router_event
.uloop
.fd
, &all_routers
, &iov
, 1, iface
);
499 // Handler for incoming router solicitations on slave interfaces
500 static void forward_router_advertisement(uint8_t *data
, size_t len
)
502 struct nd_router_advert
*adv
= (struct nd_router_advert
*)data
;
505 uint8_t *end
= data
+ len
;
506 uint8_t *mac_ptr
= NULL
;
507 struct in6_addr
*dns_ptr
= NULL
;
508 size_t dns_count
= 0;
510 struct icmpv6_opt
*opt
;
511 icmpv6_for_each_option(opt
, &adv
[1], end
) {
512 if (opt
->type
== ND_OPT_SOURCE_LINKADDR
) {
513 // Store address of source MAC-address
515 } else if (opt
->type
== ND_OPT_RECURSIVE_DNS
&& opt
->len
> 1) {
516 // Check if we have to rewrite DNS
517 dns_ptr
= (struct in6_addr
*)&opt
->data
[6];
518 dns_count
= (opt
->len
- 1) / 2;
522 syslog(LOG_NOTICE
, "Got a RA");
524 // Indicate a proxy, however we don't follow the rest of RFC 4389 yet
525 adv
->nd_ra_flags_reserved
|= ND_RA_FLAG_PROXY
;
527 // Forward advertisement to all slave interfaces
528 struct sockaddr_in6 all_nodes
= {AF_INET6
, 0, 0, ALL_IPV6_NODES
, 0};
529 struct iovec iov
= {data
, len
};
531 struct odhcpd_ipaddr addr
;
532 struct interface
*iface
;
533 list_for_each_entry(iface
, &interfaces
, head
) {
534 if (iface
->ra
!= RELAYD_RELAY
|| iface
->master
)
537 // Fixup source hardware address option
539 odhcpd_get_mac(iface
, mac_ptr
);
541 // If we have to rewrite DNS entries
542 if (iface
->always_rewrite_dns
&& dns_ptr
&& dns_count
> 0) {
543 const struct in6_addr
*rewrite
= iface
->dns
;
544 size_t rewrite_cnt
= iface
->dns_cnt
;
546 if (rewrite_cnt
== 0) {
547 if (odhcpd_get_interface_addresses(iface
->ifindex
, &addr
, 1) < 1)
548 continue; // Unable to comply
550 rewrite
= &addr
.addr
;
554 // Copy over any other addresses
555 for (size_t i
= 0; i
< dns_count
; ++i
) {
556 size_t j
= (i
< rewrite_cnt
) ? i
: rewrite_cnt
- 1;
557 dns_ptr
[i
] = rewrite
[j
];
561 odhcpd_send(router_event
.uloop
.fd
, &all_nodes
, &iov
, 1, iface
);