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/socket.h>
31 #include <sys/types.h>
32 #include <netinet/in.h>
33 #include <netinet/icmp6.h>
35 #include <linux/rtnetlink.h>
38 #define SOL_NETLINK 270
41 #ifndef NETLINK_ADD_MEMBERSHIP
42 #define NETLINK_ADD_MEMBERSHIP 1
46 #define IFF_LOWER_UP 0x10000
52 static bool nocarrier
= false;
54 static int sock
= -1, rtnl
= -1;
55 static int if_index
= 0;
56 static char if_name
[IF_NAMESIZE
] = {0};
57 static volatile int rs_attempt
= 0;
58 static struct in6_addr lladdr
= IN6ADDR_ANY_INIT
;
59 static unsigned int ra_options
= 0;
60 static unsigned int ra_holdoff_interval
= 0;
64 struct icmpv6_opt lladdr
;
66 .hdr
= {ND_ROUTER_SOLICIT
, 0, 0, {{0}}},
67 .lladdr
= {ND_OPT_SOURCE_LINKADDR
, 1, {0}},
70 static void ra_send_rs(int signal
__attribute__((unused
)));
72 int ra_init(const char *ifname
, const struct in6_addr
*ifid
,
73 unsigned int options
, unsigned int holdoff_interval
)
76 ra_holdoff_interval
= holdoff_interval
;
78 const pid_t ourpid
= getpid();
79 sock
= socket(AF_INET6
, SOCK_RAW
| SOCK_CLOEXEC
, IPPROTO_ICMPV6
);
83 if_index
= if_nametoindex(ifname
);
87 strncpy(if_name
, ifname
, sizeof(if_name
) - 1);
90 rtnl
= socket(AF_NETLINK
, SOCK_DGRAM
| SOCK_CLOEXEC
, NETLINK_ROUTE
);
94 struct sockaddr_nl rtnl_kernel
= { .nl_family
= AF_NETLINK
};
95 if (connect(rtnl
, (const struct sockaddr
*)&rtnl_kernel
, sizeof(rtnl_kernel
)) < 0)
98 int val
= RTNLGRP_LINK
;
99 if (setsockopt(rtnl
, SOL_NETLINK
, NETLINK_ADD_MEMBERSHIP
, &val
, sizeof(val
)) < 0)
102 if (fcntl(rtnl
, F_SETOWN
, ourpid
) < 0)
105 if (fcntl(rtnl
, F_SETFL
, fcntl(sock
, F_GETFL
) | O_ASYNC
) < 0)
110 struct ifinfomsg ifi
;
112 .hdr
= {sizeof(req
), RTM_GETLINK
, NLM_F_REQUEST
, 1, 0},
113 .ifi
= {.ifi_index
= if_index
}
115 if (send(rtnl
, &req
, sizeof(req
), 0) < 0)
120 // Filter ICMPv6 package types
121 struct icmp6_filter filt
;
122 ICMP6_FILTER_SETBLOCKALL(&filt
);
123 ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT
, &filt
);
124 if (setsockopt(sock
, IPPROTO_ICMPV6
, ICMP6_FILTER
, &filt
, sizeof(filt
)) < 0)
128 struct ipv6_mreq an
= {ALL_IPV6_NODES
, if_index
};
129 if (setsockopt(sock
, IPPROTO_IPV6
, IPV6_ADD_MEMBERSHIP
, &an
, sizeof(an
)) < 0)
132 // Let the kernel compute our checksums
134 if (setsockopt(sock
, IPPROTO_RAW
, IPV6_CHECKSUM
, &val
, sizeof(val
)) < 0)
137 // This is required by RFC 4861
139 if (setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
)) < 0)
142 // Receive multicast hops
144 if (setsockopt(sock
, IPPROTO_IPV6
, IPV6_RECVHOPLIMIT
, &val
, sizeof(val
)) < 0)
147 // Bind to one device
148 if (setsockopt(sock
, SOL_SOCKET
, SO_BINDTODEVICE
, ifname
, strlen(ifname
)) < 0)
152 if (fcntl(sock
, F_SETOWN
, ourpid
) < 0)
155 val
= fcntl(sock
, F_GETFL
);
159 if (fcntl(sock
, F_SETFL
, val
| O_ASYNC
) < 0)
163 signal(SIGALRM
, ra_send_rs
);
178 static void ra_send_rs(int signal
__attribute__((unused
)))
180 const struct sockaddr_in6 dest
= {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, if_index
};
181 const struct icmpv6_opt llnull
= {ND_OPT_SOURCE_LINKADDR
, 1, {0}};
184 if ((rs_attempt
% 2 == 0) && memcmp(&rs
.lladdr
, &llnull
, sizeof(llnull
)))
187 len
= sizeof(struct icmp6_hdr
);
189 if (sendto(sock
, &rs
, len
, MSG_DONTWAIT
, (struct sockaddr
*)&dest
, sizeof(dest
)) < 0)
190 syslog(LOG_ERR
, "Failed to send RS (%s)", strerror(errno
));
192 if (++rs_attempt
<= 3)
196 static int16_t pref_to_priority(uint8_t flags
)
198 flags
= (flags
>> 3) & 0x03;
200 return (flags
== 0x0) ? 512 : (flags
== 0x1) ? 384 :
201 (flags
== 0x3) ? 640 : -1;
204 bool ra_link_up(void)
206 static bool firstcall
= true;
209 struct ifinfomsg msg
;
216 read
= recv(rtnl
, &resp
, sizeof(resp
), MSG_DONTWAIT
);
218 if (read
< 0 || !NLMSG_OK(&resp
.hdr
, (size_t)read
) ||
219 resp
.hdr
.nlmsg_type
!= RTM_NEWLINK
||
220 resp
.msg
.ifi_index
!= if_index
)
223 ssize_t alen
= NLMSG_PAYLOAD(&resp
.hdr
, sizeof(resp
.msg
));
224 for (struct rtattr
*rta
= (struct rtattr
*)(resp
.pad
);
225 RTA_OK(rta
, alen
); rta
= RTA_NEXT(rta
, alen
)) {
226 if (rta
->rta_type
== IFLA_ADDRESS
&&
227 RTA_PAYLOAD(rta
) >= sizeof(rs
.lladdr
.data
))
228 memcpy(rs
.lladdr
.data
, RTA_DATA(rta
), sizeof(rs
.lladdr
.data
));
231 bool hascarrier
= resp
.msg
.ifi_flags
& IFF_LOWER_UP
;
232 if (!firstcall
&& nocarrier
!= !hascarrier
)
235 nocarrier
= !hascarrier
;
240 syslog(LOG_NOTICE
, "carrier => %i event on %s", (int)!nocarrier
, if_name
);
249 static bool ra_icmpv6_valid(struct sockaddr_in6
*source
, int hlim
, uint8_t *data
, size_t len
)
251 struct icmp6_hdr
*hdr
= (struct icmp6_hdr
*)data
;
252 struct icmpv6_opt
*opt
, *end
= (struct icmpv6_opt
*)&data
[len
];
254 if (hlim
!= 255 || len
< sizeof(*hdr
) || hdr
->icmp6_code
)
257 switch (hdr
->icmp6_type
) {
258 case ND_ROUTER_ADVERT
:
259 if (!IN6_IS_ADDR_LINKLOCAL(&source
->sin6_addr
))
262 opt
= (struct icmpv6_opt
*)((struct nd_router_advert
*)data
+ 1);
269 icmpv6_for_each_option(opt
, opt
, end
)
275 int ra_conf_hoplimit(int newvalue
)
277 static int value
= 0;
285 int ra_conf_mtu(int newvalue
)
287 static int value
= 0;
289 if (newvalue
>= 1280 && newvalue
<= 65535)
295 int ra_conf_reachable(int newvalue
)
297 static int value
= 0;
299 if (newvalue
> 0 && newvalue
<= 3600000)
305 int ra_conf_retransmit(int newvalue
)
307 static int value
= 0;
309 if (newvalue
> 0 && newvalue
<= 60000)
315 bool ra_process(void)
318 bool changed
= false;
319 uint8_t buf
[1500] _aligned(4);
322 uint8_t buf
[CMSG_SPACE(sizeof(int))];
324 struct nd_router_advert
*adv
= (struct nd_router_advert
*)buf
;
325 struct odhcp6c_entry
*entry
= alloca(sizeof(*entry
) + 256);
326 const struct in6_addr any
= IN6ADDR_ANY_INIT
;
328 memset(entry
, 0, sizeof(*entry
));
330 if (IN6_IS_ADDR_UNSPECIFIED(&lladdr
)) {
331 struct sockaddr_in6 addr
= {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, if_index
};
332 socklen_t alen
= sizeof(addr
);
333 int sock
= socket(AF_INET6
, SOCK_RAW
, IPPROTO_ICMPV6
);
336 if (!connect(sock
, (struct sockaddr
*)&addr
, sizeof(addr
)) &&
337 !getsockname(sock
, (struct sockaddr
*)&addr
, &alen
))
338 lladdr
= addr
.sin6_addr
;
345 struct sockaddr_in6 from
;
346 struct iovec iov
= {buf
, sizeof(buf
)};
347 struct msghdr msg
= {
348 .msg_name
= (void *) &from
,
349 .msg_namelen
= sizeof(from
),
352 .msg_control
= cmsg_buf
.buf
,
353 .msg_controllen
= sizeof(cmsg_buf
),
357 ssize_t len
= recvmsg(sock
, &msg
, MSG_DONTWAIT
);
361 if (IN6_IS_ADDR_UNSPECIFIED(&lladdr
))
365 for (struct cmsghdr
*ch
= CMSG_FIRSTHDR(&msg
); ch
!= NULL
;
366 ch
= CMSG_NXTHDR(&msg
, ch
))
367 if (ch
->cmsg_level
== IPPROTO_IPV6
&&
368 ch
->cmsg_type
== IPV6_HOPLIMIT
)
369 memcpy(&hlim
, CMSG_DATA(ch
), sizeof(hlim
));
371 if (!ra_icmpv6_valid(&from
, hlim
, buf
, len
))
374 // Stop sending solicits
375 if (rs_attempt
> 0) {
384 uint32_t router_valid
= ntohs(adv
->nd_ra_router_lifetime
);
386 // Parse default route
389 entry
->router
= from
.sin6_addr
;
390 entry
->priority
= pref_to_priority(adv
->nd_ra_flags_reserved
);
391 if (entry
->priority
< 0)
392 entry
->priority
= pref_to_priority(0);
394 entry
->valid
= router_valid
;
395 entry
->preferred
= entry
->valid
;
396 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, entry
,
397 0, ra_holdoff_interval
);
400 ra_conf_hoplimit(adv
->nd_ra_curhoplimit
);
402 // Parse ND parameters
403 ra_conf_reachable(ntohl(adv
->nd_ra_reachable
));
404 ra_conf_retransmit(ntohl(adv
->nd_ra_retransmit
));
407 struct icmpv6_opt
*opt
;
408 icmpv6_for_each_option(opt
, &adv
[1], &buf
[len
]) {
409 if (opt
->type
== ND_OPT_MTU
) {
410 uint32_t *mtu
= (uint32_t*)&opt
->data
[2];
411 ra_conf_mtu(ntohl(*mtu
));
412 } else if (opt
->type
== ND_OPT_ROUTE_INFORMATION
&& opt
->len
<= 3) {
413 entry
->router
= from
.sin6_addr
;
415 entry
->priority
= pref_to_priority(opt
->data
[1]);
416 entry
->length
= opt
->data
[0];
417 uint32_t *valid
= (uint32_t*)&opt
->data
[2];
418 entry
->valid
= ntohl(*valid
);
419 memcpy(&entry
->target
, &opt
->data
[6], (opt
->len
- 1) * 8);
421 if (entry
->length
> 128 || IN6_IS_ADDR_LINKLOCAL(&entry
->target
)
422 || IN6_IS_ADDR_LOOPBACK(&entry
->target
)
423 || IN6_IS_ADDR_MULTICAST(&entry
->target
))
426 if (entry
->priority
> 0)
427 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, entry
,
428 0, ra_holdoff_interval
);
429 } else if (opt
->type
== ND_OPT_PREFIX_INFORMATION
&& opt
->len
== 4) {
430 struct nd_opt_prefix_info
*pinfo
= (struct nd_opt_prefix_info
*)opt
;
432 entry
->target
= pinfo
->nd_opt_pi_prefix
;
433 entry
->priority
= 256;
434 entry
->length
= pinfo
->nd_opt_pi_prefix_len
;
435 entry
->valid
= ntohl(pinfo
->nd_opt_pi_valid_time
);
436 entry
->preferred
= ntohl(pinfo
->nd_opt_pi_preferred_time
);
438 if (entry
->length
> 128 || IN6_IS_ADDR_LINKLOCAL(&entry
->target
)
439 || IN6_IS_ADDR_LOOPBACK(&entry
->target
)
440 || IN6_IS_ADDR_MULTICAST(&entry
->target
)
441 || entry
->valid
< entry
->preferred
)
444 if (pinfo
->nd_opt_pi_flags_reserved
& ND_OPT_PI_FLAG_ONLINK
)
445 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, entry
,
446 7200, ra_holdoff_interval
);
448 if (!(pinfo
->nd_opt_pi_flags_reserved
& ND_OPT_PI_FLAG_AUTO
) ||
449 pinfo
->nd_opt_pi_prefix_len
!= 64)
452 entry
->target
.s6_addr32
[2] = lladdr
.s6_addr32
[2];
453 entry
->target
.s6_addr32
[3] = lladdr
.s6_addr32
[3];
455 changed
|= odhcp6c_update_entry(STATE_RA_PREFIX
, entry
,
456 7200, ra_holdoff_interval
);
457 } else if (opt
->type
== ND_OPT_RECURSIVE_DNS
&& opt
->len
> 2) {
458 entry
->router
= from
.sin6_addr
;
461 uint32_t *valid
= (uint32_t*)&opt
->data
[2];
462 entry
->valid
= ntohl(*valid
);
463 entry
->preferred
= 0;
465 for (ssize_t i
= 0; i
< (opt
->len
- 1) / 2; ++i
) {
466 memcpy(&entry
->target
, &opt
->data
[6 + i
* sizeof(entry
->target
)],
467 sizeof(entry
->target
));
468 changed
|= odhcp6c_update_entry(STATE_RA_DNS
, entry
,
469 0, ra_holdoff_interval
);
471 } else if (opt
->type
== ND_OPT_DNSSL
&& opt
->len
> 1) {
472 uint32_t *valid
= (uint32_t*)&opt
->data
[2];
473 uint8_t *buf
= &opt
->data
[6];
474 uint8_t *end
= &buf
[(opt
->len
- 1) * 8];
476 entry
->router
= from
.sin6_addr
;
477 entry
->valid
= ntohl(*valid
);
480 int len
= dn_expand(buf
, end
, buf
, (char*)entry
->auxtarget
, 256);
485 entry
->auxlen
= strlen((char*)entry
->auxtarget
);
487 if (entry
->auxlen
== 0)
490 changed
|= odhcp6c_update_entry(STATE_RA_SEARCH
, entry
,
491 0, ra_holdoff_interval
);
497 if (ra_options
& RA_RDNSS_DEFAULT_LIFETIME
) {
498 int states
[2] = {STATE_RA_DNS
, STATE_RA_SEARCH
};
500 for (size_t i
= 0; i
< 2; ++i
) {
502 uint8_t *start
= odhcp6c_get_state(states
[i
], &ra_dns_len
);
504 for (struct odhcp6c_entry
*c
= (struct odhcp6c_entry
*)start
;
505 (uint8_t*)c
< &start
[ra_dns_len
] &&
506 (uint8_t*)odhcp6c_next_entry(c
) <= &start
[ra_dns_len
];
507 c
= odhcp6c_next_entry(c
)) {
508 if (IN6_ARE_ADDR_EQUAL(&c
->router
, &from
.sin6_addr
) &&
509 c
->valid
> router_valid
)
510 c
->valid
= router_valid
;
519 return found
&& changed
;