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;
54 static bool ptp_link
= false;
56 static int sock
= -1, rtnl
= -1;
57 static int if_index
= 0;
58 static char if_name
[IF_NAMESIZE
] = {0};
59 static volatile int rs_attempt
= 0;
60 static struct in6_addr lladdr
= IN6ADDR_ANY_INIT
;
61 static unsigned int ra_options
= 0;
62 static unsigned int ra_holdoff_interval
= 0;
63 static int ra_hoplimit
= 0;
64 static int ra_mtu
= 0;
65 static int ra_reachable
= 0;
66 static int ra_retransmit
= 0;
70 struct icmpv6_opt lladdr
;
72 .hdr
= {ND_ROUTER_SOLICIT
, 0, 0, {{0}}},
73 .lladdr
= {ND_OPT_SOURCE_LINKADDR
, 1, {0}},
76 static void ra_send_rs(int signal
__attribute__((unused
)));
78 int ra_init(const char *ifname
, const struct in6_addr
*ifid
,
79 unsigned int options
, unsigned int holdoff_interval
)
84 ra_holdoff_interval
= holdoff_interval
;
86 const pid_t ourpid
= getpid();
87 sock
= socket(AF_INET6
, SOCK_RAW
| SOCK_CLOEXEC
, IPPROTO_ICMPV6
);
91 memset(&ifr
, 0, sizeof(ifr
));
92 strncpy(ifr
.ifr_name
, ifname
, sizeof(ifr
.ifr_name
) - 1);
93 if (ioctl(sock
, SIOCGIFFLAGS
, &ifr
) < 0)
96 ptp_link
= !!(ifr
.ifr_flags
& IFF_POINTOPOINT
);
98 memset(&ifr
, 0, sizeof(ifr
));
99 strncpy(ifr
.ifr_name
, ifname
, sizeof(ifr
.ifr_name
) - 1);
100 if (ioctl(sock
, SIOCGIFINDEX
, &ifr
) < 0)
103 if_index
= ifr
.ifr_ifindex
;
106 rtnl
= socket(AF_NETLINK
, SOCK_DGRAM
| SOCK_CLOEXEC
, NETLINK_ROUTE
);
110 struct sockaddr_nl rtnl_kernel
= { .nl_family
= AF_NETLINK
};
111 if (connect(rtnl
, (const struct sockaddr
*)&rtnl_kernel
, sizeof(rtnl_kernel
)) < 0)
114 int val
= RTNLGRP_LINK
;
115 if (setsockopt(rtnl
, SOL_NETLINK
, NETLINK_ADD_MEMBERSHIP
, &val
, sizeof(val
)) < 0)
118 if (fcntl(rtnl
, F_SETOWN
, ourpid
) < 0)
121 if (fcntl(rtnl
, F_SETFL
, fcntl(sock
, F_GETFL
) | O_ASYNC
) < 0)
126 struct ifinfomsg ifi
;
128 .hdr
= {sizeof(req
), RTM_GETLINK
, NLM_F_REQUEST
, 1, 0},
129 .ifi
= {.ifi_index
= if_index
}
131 if (send(rtnl
, &req
, sizeof(req
), 0) < 0)
136 // Filter ICMPv6 package types
137 struct icmp6_filter filt
;
138 ICMP6_FILTER_SETBLOCKALL(&filt
);
139 ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT
, &filt
);
140 if (setsockopt(sock
, IPPROTO_ICMPV6
, ICMP6_FILTER
, &filt
, sizeof(filt
)) < 0)
144 struct ipv6_mreq an
= {ALL_IPV6_NODES
, if_index
};
145 if (setsockopt(sock
, IPPROTO_IPV6
, IPV6_ADD_MEMBERSHIP
, &an
, sizeof(an
)) < 0)
148 // Let the kernel compute our checksums
150 if (setsockopt(sock
, IPPROTO_RAW
, IPV6_CHECKSUM
, &val
, sizeof(val
)) < 0)
153 // This is required by RFC 4861
155 if (setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
)) < 0)
158 // Receive multicast hops
160 if (setsockopt(sock
, IPPROTO_IPV6
, IPV6_RECVHOPLIMIT
, &val
, sizeof(val
)) < 0)
163 // Bind to one device
164 if (setsockopt(sock
, SOL_SOCKET
, SO_BINDTODEVICE
, ifname
, strlen(ifname
)) < 0)
168 if (fcntl(sock
, F_SETOWN
, ourpid
) < 0)
171 val
= fcntl(sock
, F_GETFL
);
175 if (fcntl(sock
, F_SETFL
, val
| O_ASYNC
) < 0)
179 signal(SIGALRM
, ra_send_rs
);
194 static void ra_send_rs(int signal
__attribute__((unused
)))
196 const struct sockaddr_in6 dest
= {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, if_index
};
197 const struct icmpv6_opt llnull
= {ND_OPT_SOURCE_LINKADDR
, 1, {0}};
200 if ((rs_attempt
% 2 == 0) && memcmp(&rs
.lladdr
, &llnull
, sizeof(llnull
)))
203 len
= sizeof(struct icmp6_hdr
);
205 if (sendto(sock
, &rs
, len
, MSG_DONTWAIT
, (struct sockaddr
*)&dest
, sizeof(dest
)) < 0)
206 syslog(LOG_ERR
, "Failed to send RS (%s)", strerror(errno
));
208 if (++rs_attempt
<= 3)
212 static int16_t pref_to_priority(uint8_t flags
)
214 flags
= (flags
>> 3) & 0x03;
216 return (flags
== 0x0) ? 512 : (flags
== 0x1) ? 384 :
217 (flags
== 0x3) ? 640 : -1;
220 bool ra_link_up(void)
222 static bool firstcall
= true;
225 struct ifinfomsg msg
;
232 read
= recv(rtnl
, &resp
, sizeof(resp
), MSG_DONTWAIT
);
234 if (read
< 0 || !NLMSG_OK(&resp
.hdr
, (size_t)read
) ||
235 resp
.hdr
.nlmsg_type
!= RTM_NEWLINK
||
236 resp
.msg
.ifi_index
!= if_index
)
239 ssize_t alen
= NLMSG_PAYLOAD(&resp
.hdr
, sizeof(resp
.msg
));
240 for (struct rtattr
*rta
= (struct rtattr
*)(resp
.pad
);
241 RTA_OK(rta
, alen
); rta
= RTA_NEXT(rta
, alen
)) {
242 if (rta
->rta_type
== IFLA_ADDRESS
&&
243 RTA_PAYLOAD(rta
) >= sizeof(rs
.lladdr
.data
))
244 memcpy(rs
.lladdr
.data
, RTA_DATA(rta
), sizeof(rs
.lladdr
.data
));
247 bool hascarrier
= resp
.msg
.ifi_flags
& IFF_LOWER_UP
;
248 if (!firstcall
&& nocarrier
!= !hascarrier
)
251 nocarrier
= !hascarrier
;
256 syslog(LOG_NOTICE
, "carrier => %i event on %s", (int)!nocarrier
, if_name
);
265 static bool ra_icmpv6_valid(struct sockaddr_in6
*source
, int hlim
, uint8_t *data
, size_t len
)
267 struct icmp6_hdr
*hdr
= (struct icmp6_hdr
*)data
;
268 struct icmpv6_opt
*opt
, *end
= (struct icmpv6_opt
*)&data
[len
];
270 if (hlim
!= 255 || len
< sizeof(*hdr
) || hdr
->icmp6_code
)
273 switch (hdr
->icmp6_type
) {
274 case ND_ROUTER_ADVERT
:
275 if (!IN6_IS_ADDR_LINKLOCAL(&source
->sin6_addr
))
278 opt
= (struct icmpv6_opt
*)((struct nd_router_advert
*)data
+ 1);
285 icmpv6_for_each_option(opt
, opt
, end
)
291 static bool ra_set_hoplimit(int val
)
293 if (val
> 0 && val
!= ra_hoplimit
) {
301 static bool ra_set_mtu(int val
)
303 if (val
>= 1280 && val
<= 65535 && ra_mtu
!= val
) {
311 static bool ra_set_reachable(int val
)
313 if (val
> 0 && val
<= 3600000 && ra_reachable
!= val
) {
321 static bool ra_set_retransmit(int val
)
323 if (val
> 0 && val
<= 60000 && ra_retransmit
!= val
) {
331 int ra_get_hoplimit(void)
341 int ra_get_reachable(void)
346 int ra_get_retransmit(void)
348 return ra_retransmit
;
351 bool ra_process(void)
354 bool changed
= false;
355 uint8_t buf
[1500] _aligned(4);
358 uint8_t buf
[CMSG_SPACE(sizeof(int))];
360 struct nd_router_advert
*adv
= (struct nd_router_advert
*)buf
;
361 struct odhcp6c_entry
*entry
= alloca(sizeof(*entry
) + 256);
362 const struct in6_addr any
= IN6ADDR_ANY_INIT
;
364 memset(entry
, 0, sizeof(*entry
));
366 if (IN6_IS_ADDR_UNSPECIFIED(&lladdr
)) {
367 struct sockaddr_in6 addr
= {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, if_index
};
368 socklen_t alen
= sizeof(addr
);
369 int sock
= socket(AF_INET6
, SOCK_RAW
, IPPROTO_ICMPV6
);
372 if (!connect(sock
, (struct sockaddr
*)&addr
, sizeof(addr
)) &&
373 !getsockname(sock
, (struct sockaddr
*)&addr
, &alen
))
374 lladdr
= addr
.sin6_addr
;
381 struct sockaddr_in6 from
;
382 struct iovec iov
= {buf
, sizeof(buf
)};
383 struct msghdr msg
= {
384 .msg_name
= (void *) &from
,
385 .msg_namelen
= sizeof(from
),
388 .msg_control
= cmsg_buf
.buf
,
389 .msg_controllen
= sizeof(cmsg_buf
),
392 struct icmpv6_opt
*opt
;
393 uint32_t router_valid
;
396 ssize_t len
= recvmsg(sock
, &msg
, MSG_DONTWAIT
);
400 if (IN6_IS_ADDR_UNSPECIFIED(&lladdr
))
403 for (struct cmsghdr
*ch
= CMSG_FIRSTHDR(&msg
); ch
!= NULL
;
404 ch
= CMSG_NXTHDR(&msg
, ch
))
405 if (ch
->cmsg_level
== IPPROTO_IPV6
&&
406 ch
->cmsg_type
== IPV6_HOPLIMIT
)
407 memcpy(&hlim
, CMSG_DATA(ch
), sizeof(hlim
));
409 if (!ra_icmpv6_valid(&from
, hlim
, buf
, len
))
417 router_valid
= ntohs(adv
->nd_ra_router_lifetime
);
420 * Once the host sends a Router Solicitation, and receives a valid
421 * Router Advertisement with a non-zero Router Lifetime, the host MUST
422 * desist from sending additional solicitations on that interface
423 * Moreover, a host SHOULD send at least one solicitation in the case
424 * where an advertisement is received prior to having sent a solicitation.
426 if (rs_attempt
> 0 && router_valid
> 0) {
431 // Parse default route
434 entry
->router
= from
.sin6_addr
;
435 entry
->priority
= pref_to_priority(adv
->nd_ra_flags_reserved
);
436 if (entry
->priority
< 0)
437 entry
->priority
= pref_to_priority(0);
439 entry
->valid
= router_valid
;
440 entry
->preferred
= entry
->valid
;
441 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, entry
,
442 0, ra_holdoff_interval
);
445 changed
|= ra_set_hoplimit(adv
->nd_ra_curhoplimit
);
447 // Parse ND parameters
448 changed
|= ra_set_reachable(ntohl(adv
->nd_ra_reachable
));
449 changed
|= ra_set_retransmit(ntohl(adv
->nd_ra_retransmit
));
452 icmpv6_for_each_option(opt
, &adv
[1], &buf
[len
]) {
453 if (opt
->type
== ND_OPT_MTU
) {
454 uint32_t *mtu
= (uint32_t*)&opt
->data
[2];
455 changed
|= ra_set_mtu(ntohl(*mtu
));
456 } else if (opt
->type
== ND_OPT_ROUTE_INFORMATION
&& opt
->len
<= 3) {
457 struct icmpv6_opt_route_info
*ri
= (struct icmpv6_opt_route_info
*)opt
;
459 if (ri
->prefix_len
> 128) {
461 } else if (ri
->prefix_len
> 64) {
464 } else if (ri
->prefix_len
> 0) {
469 entry
->router
= from
.sin6_addr
;
471 entry
->priority
= pref_to_priority(ri
->flags
);
472 entry
->length
= ri
->prefix_len
;
473 entry
->valid
= ntohl(ri
->lifetime
);
474 memcpy(&entry
->target
, ri
->prefix
, (ri
->len
- 1) * 8);
476 if (IN6_IS_ADDR_LINKLOCAL(&entry
->target
)
477 || IN6_IS_ADDR_LOOPBACK(&entry
->target
)
478 || IN6_IS_ADDR_MULTICAST(&entry
->target
))
481 if (entry
->priority
> 0)
482 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, entry
,
483 0, ra_holdoff_interval
);
484 } else if (opt
->type
== ND_OPT_PREFIX_INFORMATION
&& opt
->len
== 4) {
485 struct nd_opt_prefix_info
*pinfo
= (struct nd_opt_prefix_info
*)opt
;
487 entry
->target
= pinfo
->nd_opt_pi_prefix
;
488 entry
->priority
= 256;
489 entry
->length
= pinfo
->nd_opt_pi_prefix_len
;
490 entry
->valid
= ntohl(pinfo
->nd_opt_pi_valid_time
);
491 entry
->preferred
= ntohl(pinfo
->nd_opt_pi_preferred_time
);
493 if (entry
->length
> 128 || IN6_IS_ADDR_LINKLOCAL(&entry
->target
)
494 || IN6_IS_ADDR_LOOPBACK(&entry
->target
)
495 || IN6_IS_ADDR_MULTICAST(&entry
->target
)
496 || entry
->valid
< entry
->preferred
)
499 if ((pinfo
->nd_opt_pi_flags_reserved
& ND_OPT_PI_FLAG_ONLINK
) &&
501 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, entry
,
502 7200, ra_holdoff_interval
);
504 if (!(pinfo
->nd_opt_pi_flags_reserved
& ND_OPT_PI_FLAG_AUTO
) ||
505 pinfo
->nd_opt_pi_prefix_len
!= 64)
508 entry
->target
.s6_addr32
[2] = lladdr
.s6_addr32
[2];
509 entry
->target
.s6_addr32
[3] = lladdr
.s6_addr32
[3];
511 changed
|= odhcp6c_update_entry(STATE_RA_PREFIX
, entry
,
512 7200, ra_holdoff_interval
);
513 } else if (opt
->type
== ND_OPT_RECURSIVE_DNS
&& opt
->len
> 2) {
514 entry
->router
= from
.sin6_addr
;
517 uint32_t *valid
= (uint32_t*)&opt
->data
[2];
518 entry
->valid
= ntohl(*valid
);
519 entry
->preferred
= 0;
521 for (ssize_t i
= 0; i
< (opt
->len
- 1) / 2; ++i
) {
522 memcpy(&entry
->target
, &opt
->data
[6 + i
* sizeof(entry
->target
)],
523 sizeof(entry
->target
));
524 changed
|= odhcp6c_update_entry(STATE_RA_DNS
, entry
,
525 0, ra_holdoff_interval
);
527 } else if (opt
->type
== ND_OPT_DNSSL
&& opt
->len
> 1) {
528 uint32_t *valid
= (uint32_t*)&opt
->data
[2];
529 uint8_t *buf
= &opt
->data
[6];
530 uint8_t *end
= &buf
[(opt
->len
- 1) * 8];
532 entry
->router
= from
.sin6_addr
;
533 entry
->valid
= ntohl(*valid
);
536 int len
= dn_expand(buf
, end
, buf
, (char*)entry
->auxtarget
, 256);
541 entry
->auxlen
= strlen((char*)entry
->auxtarget
);
543 if (entry
->auxlen
== 0)
546 changed
|= odhcp6c_update_entry(STATE_RA_SEARCH
, entry
,
547 0, ra_holdoff_interval
);
553 if (ra_options
& RA_RDNSS_DEFAULT_LIFETIME
) {
554 int states
[2] = {STATE_RA_DNS
, STATE_RA_SEARCH
};
556 for (size_t i
= 0; i
< 2; ++i
) {
558 uint8_t *start
= odhcp6c_get_state(states
[i
], &ra_dns_len
);
560 for (struct odhcp6c_entry
*c
= (struct odhcp6c_entry
*)start
;
561 (uint8_t*)c
< &start
[ra_dns_len
] &&
562 (uint8_t*)odhcp6c_next_entry(c
) <= &start
[ra_dns_len
];
563 c
= odhcp6c_next_entry(c
)) {
564 if (IN6_ARE_ADDR_EQUAL(&c
->router
, &from
.sin6_addr
) &&
565 c
->valid
> router_valid
)
566 c
->valid
= router_valid
;
575 return found
&& changed
;