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 <arpa/inet.h>
24 #include <net/route.h>
30 static void forward_router_solicitation(const struct interface
*iface
);
31 static void forward_router_advertisement(uint8_t *data
, size_t len
);
33 static void handle_icmpv6(void *addr
, void *data
, size_t len
,
34 struct interface
*iface
, void *dest
);
35 static void trigger_router_advert(struct uloop_timeout
*event
);
36 static void sigusr1_refresh(int signal
);
38 static struct odhcpd_event router_event
= {.uloop
= {.fd
= -1}, .handle_dgram
= handle_icmpv6
, };
40 static FILE *fp_route
= NULL
;
43 #define TIME_LEFT(t1, now) ((t1) != UINT32_MAX ? (t1) - (now) : UINT32_MAX)
48 int sock
= socket(AF_INET6
, SOCK_RAW
| SOCK_CLOEXEC
, IPPROTO_ICMPV6
);
49 if (sock
< 0 && errno
!= EAFNOSUPPORT
) {
50 syslog(LOG_ERR
, "Failed to open RAW-socket: %s", strerror(errno
));
54 // Let the kernel compute our checksums
56 setsockopt(sock
, IPPROTO_RAW
, IPV6_CHECKSUM
, &val
, sizeof(val
));
58 // This is required by RFC 4861
60 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
));
61 setsockopt(sock
, IPPROTO_IPV6
, IPV6_UNICAST_HOPS
, &val
, sizeof(val
));
63 // We need to know the source interface
65 setsockopt(sock
, IPPROTO_IPV6
, IPV6_RECVPKTINFO
, &val
, sizeof(val
));
66 setsockopt(sock
, IPPROTO_IPV6
, IPV6_RECVHOPLIMIT
, &val
, sizeof(val
));
70 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_LOOP
, &val
, sizeof(val
));
72 // Filter ICMPv6 package types
73 struct icmp6_filter filt
;
74 ICMP6_FILTER_SETBLOCKALL(&filt
);
75 ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT
, &filt
);
76 ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT
, &filt
);
77 setsockopt(sock
, IPPROTO_ICMPV6
, ICMP6_FILTER
, &filt
, sizeof(filt
));
80 router_event
.uloop
.fd
= sock
;
81 odhcpd_register(&router_event
);
83 if (!(fp_route
= fopen("/proc/net/ipv6_route", "r")))
84 syslog(LOG_ERR
, "Failed to open routing table: %s",
87 signal(SIGUSR1
, sigusr1_refresh
);
92 int setup_router_interface(struct interface
*iface
, bool enable
)
94 if (!fp_route
|| router_event
.uloop
.fd
< 0)
97 struct ipv6_mreq all_nodes
= {ALL_IPV6_NODES
, iface
->ifindex
};
98 struct ipv6_mreq all_routers
= {ALL_IPV6_ROUTERS
, iface
->ifindex
};
100 uloop_timeout_cancel(&iface
->timer_rs
);
101 iface
->timer_rs
.cb
= NULL
;
103 if (iface
->ifindex
<= 0)
106 setsockopt(router_event
.uloop
.fd
, IPPROTO_IPV6
, IPV6_DROP_MEMBERSHIP
,
107 &all_nodes
, sizeof(all_nodes
));
108 setsockopt(router_event
.uloop
.fd
, IPPROTO_IPV6
, IPV6_DROP_MEMBERSHIP
,
109 &all_routers
, sizeof(all_routers
));
113 trigger_router_advert(&iface
->timer_rs
);
115 void *mreq
= &all_routers
;
117 if (iface
->ra
== RELAYD_RELAY
&& iface
->master
) {
119 forward_router_solicitation(iface
);
120 } else if (iface
->ra
== RELAYD_SERVER
&& !iface
->master
) {
121 iface
->timer_rs
.cb
= trigger_router_advert
;
122 uloop_timeout_set(&iface
->timer_rs
, 1000);
125 if (iface
->ra
== RELAYD_RELAY
|| (iface
->ra
== RELAYD_SERVER
&& !iface
->master
))
126 setsockopt(router_event
.uloop
.fd
, IPPROTO_IPV6
,
127 IPV6_ADD_MEMBERSHIP
, mreq
, sizeof(all_nodes
));
133 // Signal handler to resend all RDs
134 static void sigusr1_refresh(_unused
int signal
)
136 struct interface
*iface
;
137 list_for_each_entry(iface
, &interfaces
, head
)
138 if (iface
->ra
== RELAYD_SERVER
&& !iface
->master
)
139 uloop_timeout_set(&iface
->timer_rs
, 1000);
142 static bool router_icmpv6_valid(struct sockaddr_in6
*source
, uint8_t *data
, size_t len
)
144 struct icmp6_hdr
*hdr
= (struct icmp6_hdr
*)data
;
145 struct icmpv6_opt
*opt
, *end
= (struct icmpv6_opt
*)&data
[len
];
147 /* Hoplimit is already checked in odhcpd_receive_packets */
148 if (len
< sizeof(*hdr
) || hdr
->icmp6_code
)
151 switch (hdr
->icmp6_type
) {
152 case ND_ROUTER_ADVERT
:
153 if (!IN6_IS_ADDR_LINKLOCAL(&source
->sin6_addr
))
156 opt
= (struct icmpv6_opt
*)((struct nd_router_advert
*)data
+ 1);
159 case ND_ROUTER_SOLICIT
:
160 opt
= (struct icmpv6_opt
*)((struct nd_router_solicit
*)data
+ 1);
167 icmpv6_for_each_option(opt
, opt
, end
)
168 if (opt
->type
== ND_OPT_SOURCE_LINKADDR
&&
169 IN6_IS_ADDR_UNSPECIFIED(&source
->sin6_addr
) &&
170 hdr
->icmp6_type
== ND_ROUTER_SOLICIT
)
173 // Check all options parsed successfully
178 // Detect whether a default route exists, also find the source prefixes
179 static bool parse_routes(struct odhcpd_ipaddr
*n
, ssize_t len
)
183 char line
[512], ifname
[16];
184 bool found_default
= false;
185 struct odhcpd_ipaddr p
= {IN6ADDR_ANY_INIT
, 0, 0, 0, 0};
186 while (fgets(line
, sizeof(line
), fp_route
)) {
188 if (sscanf(line
, "00000000000000000000000000000000 00 "
189 "%*s %*s %*s %*s %*s %*s %*s %15s", ifname
) &&
190 strcmp(ifname
, "lo")) {
191 found_default
= true;
192 } else if (sscanf(line
, "%8" SCNx32
"%8" SCNx32
"%*8" SCNx32
"%*8" SCNx32
" %hhx %*s "
193 "%*s 00000000000000000000000000000000 %*s %*s %*s %" SCNx32
" lo",
194 &p
.addr
.s6_addr32
[0], &p
.addr
.s6_addr32
[1], &p
.prefix
, &rflags
) &&
195 p
.prefix
> 0 && (rflags
& RTF_NONEXTHOP
) && (rflags
& RTF_REJECT
)) {
196 // Find source prefixes by scanning through unreachable-routes
197 p
.addr
.s6_addr32
[0] = htonl(p
.addr
.s6_addr32
[0]);
198 p
.addr
.s6_addr32
[1] = htonl(p
.addr
.s6_addr32
[1]);
200 for (ssize_t i
= 0; i
< len
; ++i
) {
201 if (n
[i
].prefix
<= 64 && n
[i
].prefix
>= p
.prefix
&&
202 !odhcpd_bmemcmp(&p
.addr
, &n
[i
].addr
, p
.prefix
)) {
203 n
[i
].dprefix
= p
.prefix
;
211 return found_default
;
214 static int calc_adv_interval(struct interface
*iface
, uint32_t minvalid
,
217 uint32_t minival
= iface
->ra_mininterval
;
220 *maxival
= iface
->ra_maxinterval
;
222 if (*maxival
> minvalid
/3)
223 *maxival
= minvalid
/3;
225 if (*maxival
> MaxRtrAdvInterval
)
226 *maxival
= MaxRtrAdvInterval
;
227 else if (*maxival
< 4)
230 if (minival
< MinRtrAdvInterval
)
231 minival
= MinRtrAdvInterval
;
232 else if (minival
> (*maxival
* 3)/4)
233 minival
= (*maxival
>= 9 ? *maxival
/3 : *maxival
);
235 odhcpd_urandom(&msecs
, sizeof(msecs
));
236 msecs
= (labs(msecs
) % ((*maxival
- minival
)*1000)) + minival
*1000;
241 static uint16_t calc_ra_lifetime(struct interface
*iface
, uint32_t maxival
)
243 uint16_t lifetime
= 3*maxival
;
245 if (iface
->ra_lifetime
>= 0) {
246 lifetime
= iface
->ra_lifetime
;
247 if (lifetime
< maxival
)
249 else if (lifetime
> 9000)
256 // Router Advert server mode
257 static uint64_t send_router_advert(struct interface
*iface
, const struct in6_addr
*from
)
259 time_t now
= odhcpd_time();
260 int mtu
= odhcpd_get_interface_config(iface
->ifname
, "mtu");
261 int hlim
= odhcpd_get_interface_config(iface
->ifname
, "hop_limit");
267 struct nd_router_advert h
;
268 struct icmpv6_opt lladdr
;
269 struct nd_opt_mtu mtu
;
270 struct nd_opt_prefix_info prefix
[sizeof(iface
->ia_addr
) / sizeof(*iface
->ia_addr
)];
272 .h
= {{.icmp6_type
= ND_ROUTER_ADVERT
, .icmp6_code
= 0}, 0, 0},
273 .lladdr
= {ND_OPT_SOURCE_LINKADDR
, 1, {0}},
274 .mtu
= {ND_OPT_MTU
, 1, 0, htonl(mtu
)},
278 adv
.h
.nd_ra_curhoplimit
= hlim
;
281 adv
.h
.nd_ra_flags_reserved
= ND_RA_FLAG_OTHER
;
283 if (iface
->managed
>= RELAYD_MANAGED_MFLAG
)
284 adv
.h
.nd_ra_flags_reserved
|= ND_RA_FLAG_MANAGED
;
286 if (iface
->route_preference
< 0)
287 adv
.h
.nd_ra_flags_reserved
|= ND_RA_PREF_LOW
;
288 else if (iface
->route_preference
> 0)
289 adv
.h
.nd_ra_flags_reserved
|= ND_RA_PREF_HIGH
;
290 odhcpd_get_mac(iface
, adv
.lladdr
.data
);
292 // If not currently shutting down
293 struct odhcpd_ipaddr addrs
[RELAYD_MAX_ADDRS
];
295 uint32_t minvalid
= UINT32_MAX
;
296 bool default_route
= false;
297 bool valid_prefix
= false;
300 if (iface
->timer_rs
.cb
) {
301 ipcnt
= iface
->ia_addr_len
;
302 memcpy(addrs
, iface
->ia_addr
, ipcnt
* sizeof(*addrs
));
304 // Check default route
305 if (iface
->default_router
) {
306 default_route
= true;
308 if (iface
->default_router
> 1)
310 } else if (parse_routes(addrs
, ipcnt
))
311 default_route
= true;
314 // Construct Prefix Information options
317 struct in6_addr dns_pref
, *dns_addr
= &dns_pref
;
320 odhcpd_get_linklocal_interface_address(iface
->ifindex
, &dns_pref
);
322 for (ssize_t i
= 0; i
< ipcnt
; ++i
) {
323 struct odhcpd_ipaddr
*addr
= &addrs
[i
];
324 uint32_t preferred
= 0;
327 if (addr
->prefix
> 96 || addr
->valid
<= (uint32_t)now
) {
328 char namebuf
[INET6_ADDRSTRLEN
];
330 inet_ntop(AF_INET6
, addr
, namebuf
, sizeof(namebuf
));
331 syslog(LOG_INFO
, "Address %s (prefix %d, valid %u) not suitable as RA prefix on %s",
332 namebuf
, addr
->prefix
, addr
->valid
, iface
->ifname
);
336 struct nd_opt_prefix_info
*p
= NULL
;
337 for (size_t i
= 0; i
< cnt
; ++i
) {
338 if (addr
->prefix
== adv
.prefix
[i
].nd_opt_pi_prefix_len
&&
339 !odhcpd_bmemcmp(&adv
.prefix
[i
].nd_opt_pi_prefix
,
340 &addr
->addr
, addr
->prefix
))
345 if (cnt
>= ARRAY_SIZE(adv
.prefix
))
348 p
= &adv
.prefix
[cnt
++];
351 if (addr
->preferred
> (uint32_t)now
) {
352 preferred
= TIME_LEFT(addr
->preferred
, now
);
354 if (iface
->ra_useleasetime
&&
355 preferred
> iface
->dhcpv4_leasetime
)
356 preferred
= iface
->dhcpv4_leasetime
;
359 valid
= TIME_LEFT(addr
->valid
, now
);
360 if (iface
->ra_useleasetime
) {
361 if (valid
> iface
->dhcpv4_leasetime
)
362 valid
= iface
->dhcpv4_leasetime
;
363 } else if (!preferred
&& valid
< 7200)
366 if (minvalid
> valid
)
369 if (!IN6_IS_ADDR_ULA(&addr
->addr
) || iface
->default_router
)
372 odhcpd_bmemcpy(&p
->nd_opt_pi_prefix
, &addr
->addr
,
373 (iface
->ra_advrouter
) ? 128 : addr
->prefix
);
374 p
->nd_opt_pi_type
= ND_OPT_PREFIX_INFORMATION
;
375 p
->nd_opt_pi_len
= 4;
376 p
->nd_opt_pi_prefix_len
= (addr
->prefix
< 64) ? 64 : addr
->prefix
;
377 p
->nd_opt_pi_flags_reserved
= 0;
378 if (!iface
->ra_not_onlink
)
379 p
->nd_opt_pi_flags_reserved
|= ND_OPT_PI_FLAG_ONLINK
;
380 if (iface
->managed
< RELAYD_MANAGED_NO_AFLAG
&& addr
->prefix
<= 64)
381 p
->nd_opt_pi_flags_reserved
|= ND_OPT_PI_FLAG_AUTO
;
382 if (iface
->ra_advrouter
)
383 p
->nd_opt_pi_flags_reserved
|= ND_OPT_PI_FLAG_RADDR
;
384 p
->nd_opt_pi_preferred_time
= htonl(preferred
);
385 p
->nd_opt_pi_valid_time
= htonl(valid
);
388 // Calculate periodic transmit
390 int msecs
= calc_adv_interval(iface
, minvalid
, &maxival
);
394 syslog(LOG_WARNING
, "A default route is present but there is no public prefix "
395 "on %s thus we don't announce a default route!", iface
->ifname
);
396 adv
.h
.nd_ra_router_lifetime
= 0;
398 adv
.h
.nd_ra_router_lifetime
= htons(calc_ra_lifetime(iface
, maxival
));
401 adv
.h
.nd_ra_router_lifetime
= 0;
403 syslog(LOG_INFO
, "Using a RA lifetime of %d seconds on %s", ntohs(adv
.h
.nd_ra_router_lifetime
), iface
->ifname
);
406 if (iface
->dns_cnt
> 0) {
407 dns_addr
= iface
->dns
;
408 dns_cnt
= iface
->dns_cnt
;
411 if (!dns_addr
|| IN6_IS_ADDR_UNSPECIFIED(dns_addr
))
420 } dns
= {ND_OPT_RECURSIVE_DNS
, (1 + (2 * dns_cnt
)), 0, 0, 0};
424 // DNS Search options
425 uint8_t search_buf
[256], *search_domain
= iface
->search
;
426 size_t search_len
= iface
->search_len
, search_padded
= 0;
428 if (!search_domain
&& !res_init() && _res
.dnsrch
[0] && _res
.dnsrch
[0][0]) {
429 int len
= dn_comp(_res
.dnsrch
[0], search_buf
,
430 sizeof(search_buf
), NULL
, NULL
);
432 search_domain
= search_buf
;
438 search_padded
= ((search_len
+ 7) & (~7)) + 8;
447 } *search
= alloca(sizeof(*search
) + search_padded
);
449 search
->type
= ND_OPT_DNS_SEARCH
;
450 search
->len
= search_len
? ((sizeof(*search
) + search_padded
) / 8) : 0;
453 memcpy(search
->name
, search_domain
, search_len
);
454 memset(&search
->name
[search_len
], 0, search_padded
- search_len
);
457 size_t routes_cnt
= 0;
465 } routes
[RELAYD_MAX_PREFIXES
];
467 for (ssize_t i
= 0; i
< ipcnt
; ++i
) {
468 struct odhcpd_ipaddr
*addr
= &addrs
[i
];
469 if (addr
->dprefix
> 64 || addr
->dprefix
== 0 || addr
->valid
<= (uint32_t)now
||
470 (addr
->dprefix
== 64 && addr
->prefix
== 64)) {
471 continue; // Address not suitable
472 } else if (addr
->dprefix
> 32) {
473 addr
->addr
.s6_addr32
[1] &= htonl(~((1U << (64 - addr
->dprefix
)) - 1));
474 } else if (addr
->dprefix
<= 32) {
475 addr
->addr
.s6_addr32
[0] &= htonl(~((1U << (32 - addr
->dprefix
)) - 1));
476 addr
->addr
.s6_addr32
[1] = 0;
479 routes
[routes_cnt
].type
= ND_OPT_ROUTE_INFO
;
480 routes
[routes_cnt
].len
= sizeof(*routes
) / 8;
481 routes
[routes_cnt
].prefix
= addr
->dprefix
;
482 routes
[routes_cnt
].flags
= 0;
483 if (iface
->route_preference
< 0)
484 routes
[routes_cnt
].flags
|= ND_RA_PREF_LOW
;
485 else if (iface
->route_preference
> 0)
486 routes
[routes_cnt
].flags
|= ND_RA_PREF_HIGH
;
487 routes
[routes_cnt
].lifetime
= htonl(TIME_LEFT(addr
->valid
, now
));
488 routes
[routes_cnt
].addr
[0] = addr
->addr
.s6_addr32
[0];
489 routes
[routes_cnt
].addr
[1] = addr
->addr
.s6_addr32
[1];
490 routes
[routes_cnt
].addr
[2] = 0;
491 routes
[routes_cnt
].addr
[3] = 0;
496 search
->lifetime
= htonl(maxival
*10);
497 dns
.lifetime
= search
->lifetime
;
499 struct icmpv6_opt adv_interval
= {
500 .type
= ND_OPT_RTR_ADV_INTERVAL
,
502 .data
= {0, 0, (maxival
*1000) >> 24, (maxival
*1000) >> 16, (maxival
*1000) >> 8, maxival
*1000}
505 struct iovec iov
[RA_IOV_LEN
] = {
506 {&adv
, (uint8_t*)&adv
.prefix
[cnt
] - (uint8_t*)&adv
},
507 {&routes
, routes_cnt
* sizeof(*routes
)},
508 {&dns
, (dns_cnt
) ? sizeof(dns
) : 0},
509 {dns_addr
, dns_cnt
* sizeof(*dns_addr
)},
510 {search
, search
->len
* 8},
511 {&adv_interval
, adv_interval
.len
* 8}};
512 struct sockaddr_in6 dest
= {AF_INET6
, 0, 0, ALL_IPV6_NODES
, 0};
514 if (from
&& !IN6_IS_ADDR_UNSPECIFIED(from
))
515 dest
.sin6_addr
= *from
;
517 odhcpd_send(router_event
.uloop
.fd
,
518 &dest
, iov
, ARRAY_SIZE(iov
), iface
);
524 static void trigger_router_advert(struct uloop_timeout
*event
)
526 struct interface
*iface
= container_of(event
, struct interface
, timer_rs
);
527 int msecs
= send_router_advert(iface
, NULL
);
529 // Rearm timer if not shut down
531 uloop_timeout_set(event
, msecs
);
535 // Event handler for incoming ICMPv6 packets
536 static void handle_icmpv6(void *addr
, void *data
, size_t len
,
537 struct interface
*iface
, _unused
void *dest
)
539 struct icmp6_hdr
*hdr
= data
;
540 struct sockaddr_in6
*from
= addr
;
542 if (!router_icmpv6_valid(addr
, data
, len
))
545 if ((iface
->ra
== RELAYD_SERVER
&& !iface
->master
)) { // Server mode
546 if (hdr
->icmp6_type
== ND_ROUTER_SOLICIT
)
547 send_router_advert(iface
, &from
->sin6_addr
);
548 } else if (iface
->ra
== RELAYD_RELAY
) { // Relay mode
549 if (hdr
->icmp6_type
== ND_ROUTER_ADVERT
&& iface
->master
)
550 forward_router_advertisement(data
, len
);
551 else if (hdr
->icmp6_type
== ND_ROUTER_SOLICIT
&& !iface
->master
)
552 forward_router_solicitation(odhcpd_get_master_interface());
557 // Forward router solicitation
558 static void forward_router_solicitation(const struct interface
*iface
)
563 struct icmp6_hdr rs
= {ND_ROUTER_SOLICIT
, 0, 0, {{0}}};
564 struct iovec iov
= {&rs
, sizeof(rs
)};
565 struct sockaddr_in6 all_routers
=
566 {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, iface
->ifindex
};
568 syslog(LOG_NOTICE
, "Sending RS to %s", iface
->ifname
);
569 odhcpd_send(router_event
.uloop
.fd
, &all_routers
, &iov
, 1, iface
);
573 // Handler for incoming router solicitations on slave interfaces
574 static void forward_router_advertisement(uint8_t *data
, size_t len
)
576 struct nd_router_advert
*adv
= (struct nd_router_advert
*)data
;
579 uint8_t *end
= data
+ len
;
580 uint8_t *mac_ptr
= NULL
;
581 struct in6_addr
*dns_ptr
= NULL
;
582 size_t dns_count
= 0;
584 struct icmpv6_opt
*opt
;
585 icmpv6_for_each_option(opt
, &adv
[1], end
) {
586 if (opt
->type
== ND_OPT_SOURCE_LINKADDR
) {
587 // Store address of source MAC-address
589 } else if (opt
->type
== ND_OPT_RECURSIVE_DNS
&& opt
->len
> 1) {
590 // Check if we have to rewrite DNS
591 dns_ptr
= (struct in6_addr
*)&opt
->data
[6];
592 dns_count
= (opt
->len
- 1) / 2;
596 syslog(LOG_NOTICE
, "Got a RA");
598 // Indicate a proxy, however we don't follow the rest of RFC 4389 yet
599 adv
->nd_ra_flags_reserved
|= ND_RA_FLAG_PROXY
;
601 // Forward advertisement to all slave interfaces
602 struct sockaddr_in6 all_nodes
= {AF_INET6
, 0, 0, ALL_IPV6_NODES
, 0};
603 struct iovec iov
= {data
, len
};
605 struct interface
*iface
;
606 list_for_each_entry(iface
, &interfaces
, head
) {
607 if (iface
->ra
!= RELAYD_RELAY
|| iface
->master
)
610 // Fixup source hardware address option
612 odhcpd_get_mac(iface
, mac_ptr
);
614 // If we have to rewrite DNS entries
615 if (iface
->always_rewrite_dns
&& dns_ptr
&& dns_count
> 0) {
616 const struct in6_addr
*rewrite
= iface
->dns
;
617 struct in6_addr addr
;
618 size_t rewrite_cnt
= iface
->dns_cnt
;
620 if (rewrite_cnt
== 0) {
621 if (odhcpd_get_linklocal_interface_address(iface
->ifindex
, &addr
))
622 continue; // Unable to comply
628 // Copy over any other addresses
629 for (size_t i
= 0; i
< dns_count
; ++i
) {
630 size_t j
= (i
< rewrite_cnt
) ? i
: rewrite_cnt
- 1;
631 dns_ptr
[i
] = rewrite
[j
];
635 odhcpd_send(router_event
.uloop
.fd
, &all_nodes
, &iov
, 1, iface
);