2 * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
3 * Copyright (C) 2017-2018 Hans Dedecker <dedeckeh@gmail.com>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License v2 as published by
7 * the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
29 #include <arpa/inet.h>
30 #include <sys/ioctl.h>
31 #include <sys/socket.h>
32 #include <sys/types.h>
33 #include <netinet/in.h>
34 #include <netinet/icmp6.h>
36 #include <linux/rtnetlink.h>
39 #define SOL_NETLINK 270
42 #ifndef NETLINK_ADD_MEMBERSHIP
43 #define NETLINK_ADD_MEMBERSHIP 1
47 #define IFF_LOWER_UP 0x10000
53 static bool nocarrier
= false;
55 static int sock
= -1, rtnl
= -1;
56 static int if_index
= 0;
57 static char if_name
[IF_NAMESIZE
] = {0};
58 static volatile int rs_attempt
= 0;
59 static struct in6_addr lladdr
= IN6ADDR_ANY_INIT
;
60 static unsigned int ra_options
= 0;
61 static unsigned int ra_holdoff_interval
= 0;
62 static int ra_hoplimit
= 0;
63 static int ra_mtu
= 0;
64 static int ra_reachable
= 0;
65 static int ra_retransmit
= 0;
69 struct icmpv6_opt lladdr
;
71 .hdr
= {ND_ROUTER_SOLICIT
, 0, 0, {{0}}},
72 .lladdr
= {ND_OPT_SOURCE_LINKADDR
, 1, {0}},
75 static void ra_send_rs(int signal
__attribute__((unused
)));
77 int ra_init(const char *ifname
, const struct in6_addr
*ifid
,
78 unsigned int options
, unsigned int holdoff_interval
)
83 ra_holdoff_interval
= holdoff_interval
;
85 const pid_t ourpid
= getpid();
86 sock
= socket(AF_INET6
, SOCK_RAW
| SOCK_CLOEXEC
, IPPROTO_ICMPV6
);
90 memset(&ifr
, 0, sizeof(ifr
));
91 strncpy(ifr
.ifr_name
, ifname
, sizeof(ifr
.ifr_name
) - 1);
92 if (ioctl(sock
, SIOCGIFINDEX
, &ifr
) < 0)
95 if_index
= ifr
.ifr_ifindex
;
98 rtnl
= socket(AF_NETLINK
, SOCK_DGRAM
| SOCK_CLOEXEC
, NETLINK_ROUTE
);
102 struct sockaddr_nl rtnl_kernel
= { .nl_family
= AF_NETLINK
};
103 if (connect(rtnl
, (const struct sockaddr
*)&rtnl_kernel
, sizeof(rtnl_kernel
)) < 0)
106 int val
= RTNLGRP_LINK
;
107 if (setsockopt(rtnl
, SOL_NETLINK
, NETLINK_ADD_MEMBERSHIP
, &val
, sizeof(val
)) < 0)
110 if (fcntl(rtnl
, F_SETOWN
, ourpid
) < 0)
113 if (fcntl(rtnl
, F_SETFL
, fcntl(sock
, F_GETFL
) | O_ASYNC
) < 0)
118 struct ifinfomsg ifi
;
120 .hdr
= {sizeof(req
), RTM_GETLINK
, NLM_F_REQUEST
, 1, 0},
121 .ifi
= {.ifi_index
= if_index
}
123 if (send(rtnl
, &req
, sizeof(req
), 0) < 0)
128 // Filter ICMPv6 package types
129 struct icmp6_filter filt
;
130 ICMP6_FILTER_SETBLOCKALL(&filt
);
131 ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT
, &filt
);
132 if (setsockopt(sock
, IPPROTO_ICMPV6
, ICMP6_FILTER
, &filt
, sizeof(filt
)) < 0)
136 struct ipv6_mreq an
= {ALL_IPV6_NODES
, if_index
};
137 if (setsockopt(sock
, IPPROTO_IPV6
, IPV6_ADD_MEMBERSHIP
, &an
, sizeof(an
)) < 0)
140 // Let the kernel compute our checksums
142 if (setsockopt(sock
, IPPROTO_RAW
, IPV6_CHECKSUM
, &val
, sizeof(val
)) < 0)
145 // This is required by RFC 4861
147 if (setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
)) < 0)
150 // Receive multicast hops
152 if (setsockopt(sock
, IPPROTO_IPV6
, IPV6_RECVHOPLIMIT
, &val
, sizeof(val
)) < 0)
155 // Bind to one device
156 if (setsockopt(sock
, SOL_SOCKET
, SO_BINDTODEVICE
, ifname
, strlen(ifname
)) < 0)
160 if (fcntl(sock
, F_SETOWN
, ourpid
) < 0)
163 val
= fcntl(sock
, F_GETFL
);
167 if (fcntl(sock
, F_SETFL
, val
| O_ASYNC
) < 0)
171 signal(SIGALRM
, ra_send_rs
);
186 static void ra_send_rs(int signal
__attribute__((unused
)))
188 const struct sockaddr_in6 dest
= {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, if_index
};
189 const struct icmpv6_opt llnull
= {ND_OPT_SOURCE_LINKADDR
, 1, {0}};
192 if ((rs_attempt
% 2 == 0) && memcmp(&rs
.lladdr
, &llnull
, sizeof(llnull
)))
195 len
= sizeof(struct icmp6_hdr
);
197 if (sendto(sock
, &rs
, len
, MSG_DONTWAIT
, (struct sockaddr
*)&dest
, sizeof(dest
)) < 0)
198 syslog(LOG_ERR
, "Failed to send RS (%s)", strerror(errno
));
200 if (++rs_attempt
<= 3)
204 static int16_t pref_to_priority(uint8_t flags
)
206 flags
= (flags
>> 3) & 0x03;
208 return (flags
== 0x0) ? 512 : (flags
== 0x1) ? 384 :
209 (flags
== 0x3) ? 640 : -1;
212 bool ra_link_up(void)
214 static bool firstcall
= true;
217 struct ifinfomsg msg
;
224 read
= recv(rtnl
, &resp
, sizeof(resp
), MSG_DONTWAIT
);
226 if (read
< 0 || !NLMSG_OK(&resp
.hdr
, (size_t)read
) ||
227 resp
.hdr
.nlmsg_type
!= RTM_NEWLINK
||
228 resp
.msg
.ifi_index
!= if_index
)
231 ssize_t alen
= NLMSG_PAYLOAD(&resp
.hdr
, sizeof(resp
.msg
));
232 for (struct rtattr
*rta
= (struct rtattr
*)(resp
.pad
);
233 RTA_OK(rta
, alen
); rta
= RTA_NEXT(rta
, alen
)) {
234 if (rta
->rta_type
== IFLA_ADDRESS
&&
235 RTA_PAYLOAD(rta
) >= sizeof(rs
.lladdr
.data
))
236 memcpy(rs
.lladdr
.data
, RTA_DATA(rta
), sizeof(rs
.lladdr
.data
));
239 bool hascarrier
= resp
.msg
.ifi_flags
& IFF_LOWER_UP
;
240 if (!firstcall
&& nocarrier
!= !hascarrier
)
243 nocarrier
= !hascarrier
;
248 syslog(LOG_NOTICE
, "carrier => %i event on %s", (int)!nocarrier
, if_name
);
257 static bool ra_icmpv6_valid(struct sockaddr_in6
*source
, int hlim
, uint8_t *data
, size_t len
)
259 struct icmp6_hdr
*hdr
= (struct icmp6_hdr
*)data
;
260 struct icmpv6_opt
*opt
, *end
= (struct icmpv6_opt
*)&data
[len
];
262 if (hlim
!= 255 || len
< sizeof(*hdr
) || hdr
->icmp6_code
)
265 switch (hdr
->icmp6_type
) {
266 case ND_ROUTER_ADVERT
:
267 if (!IN6_IS_ADDR_LINKLOCAL(&source
->sin6_addr
))
270 opt
= (struct icmpv6_opt
*)((struct nd_router_advert
*)data
+ 1);
277 icmpv6_for_each_option(opt
, opt
, end
)
283 static bool ra_set_hoplimit(int val
)
285 if (val
> 0 && val
!= ra_hoplimit
) {
293 static bool ra_set_mtu(int val
)
295 if (val
>= 1280 && val
<= 65535 && ra_mtu
!= val
) {
303 static bool ra_set_reachable(int val
)
305 if (val
> 0 && val
<= 3600000 && ra_reachable
!= val
) {
313 static bool ra_set_retransmit(int val
)
315 if (val
> 0 && val
<= 60000 && ra_retransmit
!= val
) {
323 int ra_get_hoplimit(void)
333 int ra_get_reachable(void)
338 int ra_get_retransmit(void)
340 return ra_retransmit
;
343 bool ra_process(void)
346 bool changed
= false;
347 uint8_t buf
[1500] _aligned(4);
350 uint8_t buf
[CMSG_SPACE(sizeof(int))];
352 struct nd_router_advert
*adv
= (struct nd_router_advert
*)buf
;
353 struct odhcp6c_entry
*entry
= alloca(sizeof(*entry
) + 256);
354 const struct in6_addr any
= IN6ADDR_ANY_INIT
;
356 memset(entry
, 0, sizeof(*entry
));
358 if (IN6_IS_ADDR_UNSPECIFIED(&lladdr
)) {
359 struct sockaddr_in6 addr
= {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, if_index
};
360 socklen_t alen
= sizeof(addr
);
361 int sock
= socket(AF_INET6
, SOCK_RAW
, IPPROTO_ICMPV6
);
364 if (!connect(sock
, (struct sockaddr
*)&addr
, sizeof(addr
)) &&
365 !getsockname(sock
, (struct sockaddr
*)&addr
, &alen
))
366 lladdr
= addr
.sin6_addr
;
373 struct sockaddr_in6 from
;
374 struct iovec iov
= {buf
, sizeof(buf
)};
375 struct msghdr msg
= {
376 .msg_name
= (void *) &from
,
377 .msg_namelen
= sizeof(from
),
380 .msg_control
= cmsg_buf
.buf
,
381 .msg_controllen
= sizeof(cmsg_buf
),
384 struct icmpv6_opt
*opt
;
385 uint32_t router_valid
;
388 ssize_t len
= recvmsg(sock
, &msg
, MSG_DONTWAIT
);
392 if (IN6_IS_ADDR_UNSPECIFIED(&lladdr
))
395 for (struct cmsghdr
*ch
= CMSG_FIRSTHDR(&msg
); ch
!= NULL
;
396 ch
= CMSG_NXTHDR(&msg
, ch
))
397 if (ch
->cmsg_level
== IPPROTO_IPV6
&&
398 ch
->cmsg_type
== IPV6_HOPLIMIT
)
399 memcpy(&hlim
, CMSG_DATA(ch
), sizeof(hlim
));
401 if (!ra_icmpv6_valid(&from
, hlim
, buf
, len
))
409 router_valid
= ntohs(adv
->nd_ra_router_lifetime
);
412 * Once the host sends a Router Solicitation, and receives a valid
413 * Router Advertisement with a non-zero Router Lifetime, the host MUST
414 * desist from sending additional solicitations on that interface
415 * Moreover, a host SHOULD send at least one solicitation in the case
416 * where an advertisement is received prior to having sent a solicitation.
418 if (rs_attempt
> 0 && router_valid
> 0) {
423 // Parse default route
426 entry
->router
= from
.sin6_addr
;
427 entry
->priority
= pref_to_priority(adv
->nd_ra_flags_reserved
);
428 if (entry
->priority
< 0)
429 entry
->priority
= pref_to_priority(0);
431 entry
->valid
= router_valid
;
432 entry
->preferred
= entry
->valid
;
433 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, entry
,
434 0, ra_holdoff_interval
);
437 changed
|= ra_set_hoplimit(adv
->nd_ra_curhoplimit
);
439 // Parse ND parameters
440 changed
|= ra_set_reachable(ntohl(adv
->nd_ra_reachable
));
441 changed
|= ra_set_retransmit(ntohl(adv
->nd_ra_retransmit
));
444 icmpv6_for_each_option(opt
, &adv
[1], &buf
[len
]) {
445 if (opt
->type
== ND_OPT_MTU
) {
446 uint32_t *mtu
= (uint32_t*)&opt
->data
[2];
447 changed
|= ra_set_mtu(ntohl(*mtu
));
448 } else if (opt
->type
== ND_OPT_ROUTE_INFORMATION
&& opt
->len
<= 3) {
449 struct icmpv6_opt_route_info
*ri
= (struct icmpv6_opt_route_info
*)opt
;
451 if (ri
->prefix_len
> 128) {
453 } else if (ri
->prefix_len
> 64) {
456 } else if (ri
->prefix_len
> 0) {
461 entry
->router
= from
.sin6_addr
;
463 entry
->priority
= pref_to_priority(ri
->flags
);
464 entry
->length
= ri
->prefix_len
;
465 entry
->valid
= ntohl(ri
->lifetime
);
466 memcpy(&entry
->target
, ri
->prefix
, (ri
->len
- 1) * 8);
468 if (IN6_IS_ADDR_LINKLOCAL(&entry
->target
)
469 || IN6_IS_ADDR_LOOPBACK(&entry
->target
)
470 || IN6_IS_ADDR_MULTICAST(&entry
->target
))
473 if (entry
->priority
> 0)
474 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, entry
,
475 0, ra_holdoff_interval
);
476 } else if (opt
->type
== ND_OPT_PREFIX_INFORMATION
&& opt
->len
== 4) {
477 struct nd_opt_prefix_info
*pinfo
= (struct nd_opt_prefix_info
*)opt
;
479 entry
->target
= pinfo
->nd_opt_pi_prefix
;
480 entry
->priority
= 256;
481 entry
->length
= pinfo
->nd_opt_pi_prefix_len
;
482 entry
->valid
= ntohl(pinfo
->nd_opt_pi_valid_time
);
483 entry
->preferred
= ntohl(pinfo
->nd_opt_pi_preferred_time
);
485 if (entry
->length
> 128 || IN6_IS_ADDR_LINKLOCAL(&entry
->target
)
486 || IN6_IS_ADDR_LOOPBACK(&entry
->target
)
487 || IN6_IS_ADDR_MULTICAST(&entry
->target
)
488 || entry
->valid
< entry
->preferred
)
491 if (pinfo
->nd_opt_pi_flags_reserved
& ND_OPT_PI_FLAG_ONLINK
)
492 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, entry
,
493 7200, ra_holdoff_interval
);
495 if (!(pinfo
->nd_opt_pi_flags_reserved
& ND_OPT_PI_FLAG_AUTO
) ||
496 pinfo
->nd_opt_pi_prefix_len
!= 64)
499 entry
->target
.s6_addr32
[2] = lladdr
.s6_addr32
[2];
500 entry
->target
.s6_addr32
[3] = lladdr
.s6_addr32
[3];
502 changed
|= odhcp6c_update_entry(STATE_RA_PREFIX
, entry
,
503 7200, ra_holdoff_interval
);
504 } else if (opt
->type
== ND_OPT_RECURSIVE_DNS
&& opt
->len
> 2) {
505 entry
->router
= from
.sin6_addr
;
508 uint32_t *valid
= (uint32_t*)&opt
->data
[2];
509 entry
->valid
= ntohl(*valid
);
510 entry
->preferred
= 0;
512 for (ssize_t i
= 0; i
< (opt
->len
- 1) / 2; ++i
) {
513 memcpy(&entry
->target
, &opt
->data
[6 + i
* sizeof(entry
->target
)],
514 sizeof(entry
->target
));
515 changed
|= odhcp6c_update_entry(STATE_RA_DNS
, entry
,
516 0, ra_holdoff_interval
);
518 } else if (opt
->type
== ND_OPT_DNSSL
&& opt
->len
> 1) {
519 uint32_t *valid
= (uint32_t*)&opt
->data
[2];
520 uint8_t *buf
= &opt
->data
[6];
521 uint8_t *end
= &buf
[(opt
->len
- 1) * 8];
523 entry
->router
= from
.sin6_addr
;
524 entry
->valid
= ntohl(*valid
);
527 int len
= dn_expand(buf
, end
, buf
, (char*)entry
->auxtarget
, 256);
532 entry
->auxlen
= strlen((char*)entry
->auxtarget
);
534 if (entry
->auxlen
== 0)
537 changed
|= odhcp6c_update_entry(STATE_RA_SEARCH
, entry
,
538 0, ra_holdoff_interval
);
544 if (ra_options
& RA_RDNSS_DEFAULT_LIFETIME
) {
545 int states
[2] = {STATE_RA_DNS
, STATE_RA_SEARCH
};
547 for (size_t i
= 0; i
< 2; ++i
) {
549 uint8_t *start
= odhcp6c_get_state(states
[i
], &ra_dns_len
);
551 for (struct odhcp6c_entry
*c
= (struct odhcp6c_entry
*)start
;
552 (uint8_t*)c
< &start
[ra_dns_len
] &&
553 (uint8_t*)odhcp6c_next_entry(c
) <= &start
[ra_dns_len
];
554 c
= odhcp6c_next_entry(c
)) {
555 if (IN6_ARE_ADDR_EQUAL(&c
->router
, &from
.sin6_addr
) &&
556 c
->valid
> router_valid
)
557 c
->valid
= router_valid
;
566 return found
&& changed
;