2 * Copyright (C) 2012-2014 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.
27 #include <arpa/inet.h>
28 #include <sys/socket.h>
29 #include <sys/types.h>
30 #include <netinet/in.h>
31 #include <netinet/icmp6.h>
33 #include <linux/rtnetlink.h>
36 #define SOL_NETLINK 270
39 #ifndef NETLINK_ADD_MEMBERSHIP
40 #define NETLINK_ADD_MEMBERSHIP 1
44 #define IFF_LOWER_UP 0x10000
51 static bool nocarrier
= false;
53 static int sock
= -1, rtnl
= -1;
54 static int if_index
= 0;
55 static char if_name
[IF_NAMESIZE
] = {0};
56 static volatile int rs_attempt
= 0;
57 static struct in6_addr lladdr
= IN6ADDR_ANY_INIT
;
61 struct icmpv6_opt lladdr
;
63 .hdr
= {ND_ROUTER_SOLICIT
, 0, 0, {{0}}},
64 .lladdr
= {ND_OPT_SOURCE_LINKADDR
, 1, {0}},
68 static void ra_send_rs(int signal
__attribute__((unused
)));
70 int ra_init(const char *ifname
, const struct in6_addr
*ifid
)
72 const pid_t ourpid
= getpid();
73 sock
= socket(AF_INET6
, SOCK_RAW
| SOCK_CLOEXEC
, IPPROTO_ICMPV6
);
77 if_index
= if_nametoindex(ifname
);
81 strncpy(if_name
, ifname
, sizeof(if_name
) - 1);
84 rtnl
= socket(AF_NETLINK
, SOCK_DGRAM
| SOCK_CLOEXEC
, NETLINK_ROUTE
);
88 struct sockaddr_nl rtnl_kernel
= { .nl_family
= AF_NETLINK
};
89 if (connect(rtnl
, (const struct sockaddr
*)&rtnl_kernel
, sizeof(rtnl_kernel
)) < 0)
92 int val
= RTNLGRP_LINK
;
93 setsockopt(rtnl
, SOL_NETLINK
, NETLINK_ADD_MEMBERSHIP
, &val
, sizeof(val
));
94 fcntl(rtnl
, F_SETOWN
, ourpid
);
95 fcntl(rtnl
, F_SETFL
, fcntl(sock
, F_GETFL
) | O_ASYNC
);
101 .hdr
= {sizeof(req
), RTM_GETLINK
, NLM_F_REQUEST
, 1, 0},
102 .ifi
= {.ifi_index
= if_index
}
104 send(rtnl
, &req
, sizeof(req
), 0);
107 // Filter ICMPv6 package types
108 struct icmp6_filter filt
;
109 ICMP6_FILTER_SETBLOCKALL(&filt
);
110 ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT
, &filt
);
111 setsockopt(sock
, IPPROTO_ICMPV6
, ICMP6_FILTER
, &filt
, sizeof(filt
));
114 struct ipv6_mreq an
= {ALL_IPV6_NODES
, if_index
};
115 setsockopt(sock
, IPPROTO_IPV6
, IPV6_ADD_MEMBERSHIP
, &an
, sizeof(an
));
117 // Let the kernel compute our checksums
119 setsockopt(sock
, IPPROTO_RAW
, IPV6_CHECKSUM
, &val
, sizeof(val
));
121 // This is required by RFC 4861
123 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
));
125 // Receive multicast hops
127 setsockopt(sock
, IPPROTO_IPV6
, IPV6_RECVHOPLIMIT
, &val
, sizeof(val
));
129 // Bind to one device
130 setsockopt(sock
, SOL_SOCKET
, SO_BINDTODEVICE
, ifname
, strlen(ifname
));
133 fcntl(sock
, F_SETOWN
, ourpid
);
134 fcntl(sock
, F_SETFL
, fcntl(sock
, F_GETFL
) | O_ASYNC
);
137 signal(SIGALRM
, ra_send_rs
);
144 static void ra_send_rs(int signal
__attribute__((unused
)))
146 const struct sockaddr_in6 dest
= {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, if_index
};
147 const struct icmpv6_opt llnull
= {ND_OPT_SOURCE_LINKADDR
, 1, {0}};
150 if ((rs_attempt
% 2 == 0) && memcmp(&rs
.lladdr
, &llnull
, sizeof(llnull
)))
153 len
= sizeof(struct icmp6_hdr
);
155 sendto(sock
, &rs
, len
, MSG_DONTWAIT
, (struct sockaddr
*)&dest
, sizeof(dest
));
157 if (++rs_attempt
<= 3)
162 static int16_t pref_to_priority(uint8_t flags
)
164 flags
= (flags
>> 3) & 0x03;
165 return (flags
== 0x0) ? 512 : (flags
== 0x1) ? 384 :
166 (flags
== 0x3) ? 640 : -1;
170 bool ra_link_up(void)
172 static bool firstcall
= true;
175 struct ifinfomsg msg
;
183 read
= recv(rtnl
, &resp
, sizeof(resp
), MSG_DONTWAIT
);
184 if (read
< 0 || !NLMSG_OK(&resp
.hdr
, (size_t)read
) ||
185 resp
.hdr
.nlmsg_type
!= RTM_NEWLINK
||
186 resp
.msg
.ifi_index
!= if_index
)
189 ssize_t alen
= NLMSG_PAYLOAD(&resp
.hdr
, sizeof(resp
.msg
));
190 for (struct rtattr
*rta
= (struct rtattr
*)(resp
.pad
);
191 RTA_OK(rta
, alen
); rta
= RTA_NEXT(rta
, alen
)) {
192 if (rta
->rta_type
== IFLA_ADDRESS
&&
193 RTA_PAYLOAD(rta
) >= sizeof(rs
.lladdr
.data
))
194 memcpy(rs
.lladdr
.data
, RTA_DATA(rta
), sizeof(rs
.lladdr
.data
));
197 bool hascarrier
= resp
.msg
.ifi_flags
& IFF_LOWER_UP
;
198 if (!firstcall
&& nocarrier
!= !hascarrier
)
201 nocarrier
= !hascarrier
;
206 syslog(LOG_NOTICE
, "carrier => %i event on %s", (int)!nocarrier
, if_name
);
215 static bool ra_icmpv6_valid(struct sockaddr_in6
*source
, int hlim
, uint8_t *data
, size_t len
)
217 struct icmp6_hdr
*hdr
= (struct icmp6_hdr
*)data
;
218 struct icmpv6_opt
*opt
, *end
= (struct icmpv6_opt
*)&data
[len
];
220 if (hlim
!= 255 || len
< sizeof(*hdr
) || hdr
->icmp6_code
)
223 switch (hdr
->icmp6_type
) {
224 case ND_ROUTER_ADVERT
:
225 if (!IN6_IS_ADDR_LINKLOCAL(&source
->sin6_addr
))
228 opt
= (struct icmpv6_opt
*)((struct nd_router_advert
*)data
+ 1);
235 icmpv6_for_each_option(opt
, opt
, end
)
241 int ra_conf_hoplimit(int newvalue
)
243 static int value
= 0;
249 int ra_conf_mtu(int newvalue
)
251 static int value
= 0;
252 if (newvalue
>= 1280 && newvalue
<= 65535)
257 int ra_conf_reachable(int newvalue
)
259 static int value
= 0;
260 if (newvalue
> 0 && newvalue
<= 3600000)
265 int ra_conf_retransmit(int newvalue
)
267 static int value
= 0;
268 if (newvalue
> 0 && newvalue
<= 60000)
273 bool ra_process(void)
276 bool changed
= false;
277 uint8_t buf
[1500], cmsg_buf
[128];
278 struct nd_router_advert
*adv
= (struct nd_router_advert
*)buf
;
279 struct odhcp6c_entry
*entry
= alloca(sizeof(*entry
) + 256);
280 const struct in6_addr any
= IN6ADDR_ANY_INIT
;
282 memset(entry
, 0, sizeof(*entry
));
284 if (IN6_IS_ADDR_UNSPECIFIED(&lladdr
)) {
285 struct sockaddr_in6 addr
= {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, if_index
};
286 socklen_t alen
= sizeof(addr
);
287 int sock
= socket(AF_INET6
, SOCK_RAW
, IPPROTO_ICMPV6
);
289 if (!connect(sock
, (struct sockaddr
*)&addr
, sizeof(addr
)) &&
290 !getsockname(sock
, (struct sockaddr
*)&addr
, &alen
))
291 lladdr
= addr
.sin6_addr
;
297 struct sockaddr_in6 from
;
298 struct iovec iov
= {buf
, sizeof(buf
)};
299 struct msghdr msg
= {
300 .msg_name
= (void *) &from
,
301 .msg_namelen
= sizeof(from
),
304 .msg_control
= cmsg_buf
,
305 .msg_controllen
= sizeof(cmsg_buf
),
309 ssize_t len
= recvmsg(sock
, &msg
, MSG_DONTWAIT
);
313 if (IN6_IS_ADDR_UNSPECIFIED(&lladdr
))
317 for (struct cmsghdr
*ch
= CMSG_FIRSTHDR(&msg
); ch
!= NULL
;
318 ch
= CMSG_NXTHDR(&msg
, ch
))
319 if (ch
->cmsg_level
== IPPROTO_IPV6
&&
320 ch
->cmsg_type
== IPV6_HOPLIMIT
)
321 memcpy(&hlim
, CMSG_DATA(ch
), sizeof(hlim
));
323 if (!ra_icmpv6_valid(&from
, hlim
, buf
, len
))
326 // Stop sending solicits
327 if (rs_attempt
> 0) {
336 uint32_t router_valid
= ntohs(adv
->nd_ra_router_lifetime
);
338 // Parse default route
341 entry
->router
= from
.sin6_addr
;
342 entry
->priority
= pref_to_priority(adv
->nd_ra_flags_reserved
);
343 if (entry
->priority
< 0)
344 entry
->priority
= pref_to_priority(0);
345 entry
->valid
= router_valid
;
346 entry
->preferred
= entry
->valid
;
347 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, entry
, 0, true);
350 ra_conf_hoplimit(adv
->nd_ra_curhoplimit
);
352 // Parse ND parameters
353 ra_conf_reachable(ntohl(adv
->nd_ra_reachable
));
354 ra_conf_retransmit(ntohl(adv
->nd_ra_retransmit
));
357 struct icmpv6_opt
*opt
;
358 icmpv6_for_each_option(opt
, &adv
[1], &buf
[len
]) {
359 if (opt
->type
== ND_OPT_MTU
) {
360 uint32_t *mtu
= (uint32_t*)&opt
->data
[2];
361 ra_conf_mtu(ntohl(*mtu
));
362 } else if (opt
->type
== ND_OPT_ROUTE_INFORMATION
&& opt
->len
<= 3) {
363 entry
->router
= from
.sin6_addr
;
365 entry
->priority
= pref_to_priority(opt
->data
[1]);
366 entry
->length
= opt
->data
[0];
367 uint32_t *valid
= (uint32_t*)&opt
->data
[2];
368 entry
->valid
= ntohl(*valid
);
369 memcpy(&entry
->target
, &opt
->data
[6], (opt
->len
- 1) * 8);
371 if (entry
->length
> 128 || IN6_IS_ADDR_LINKLOCAL(&entry
->target
)
372 || IN6_IS_ADDR_LOOPBACK(&entry
->target
)
373 || IN6_IS_ADDR_MULTICAST(&entry
->target
))
376 if (entry
->priority
> 0)
377 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, entry
, 0, true);
378 } else if (opt
->type
== ND_OPT_PREFIX_INFORMATION
&& opt
->len
== 4) {
379 struct nd_opt_prefix_info
*pinfo
= (struct nd_opt_prefix_info
*)opt
;
381 entry
->target
= pinfo
->nd_opt_pi_prefix
;
382 entry
->priority
= 256;
383 entry
->length
= pinfo
->nd_opt_pi_prefix_len
;
384 entry
->valid
= ntohl(pinfo
->nd_opt_pi_valid_time
);
385 entry
->preferred
= ntohl(pinfo
->nd_opt_pi_preferred_time
);
387 if (entry
->length
> 128 || IN6_IS_ADDR_LINKLOCAL(&entry
->target
)
388 || IN6_IS_ADDR_LOOPBACK(&entry
->target
)
389 || IN6_IS_ADDR_MULTICAST(&entry
->target
)
390 || entry
->valid
< entry
->preferred
)
393 if (pinfo
->nd_opt_pi_flags_reserved
& ND_OPT_PI_FLAG_ONLINK
)
394 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, entry
, 7200, true);
396 if (!(pinfo
->nd_opt_pi_flags_reserved
& ND_OPT_PI_FLAG_AUTO
) ||
397 pinfo
->nd_opt_pi_prefix_len
!= 64)
400 entry
->target
.s6_addr32
[2] = lladdr
.s6_addr32
[2];
401 entry
->target
.s6_addr32
[3] = lladdr
.s6_addr32
[3];
403 changed
|= odhcp6c_update_entry(STATE_RA_PREFIX
, entry
, 7200, true);
404 } else if (opt
->type
== ND_OPT_RECURSIVE_DNS
&& opt
->len
> 2) {
405 entry
->router
= from
.sin6_addr
;
408 uint32_t *valid
= (uint32_t*)&opt
->data
[2];
409 entry
->valid
= ntohl(*valid
);
410 entry
->preferred
= 0;
412 for (ssize_t i
= 0; i
< (opt
->len
- 1) / 2; ++i
) {
413 memcpy(&entry
->target
, &opt
->data
[6 + i
* sizeof(entry
->target
)],
414 sizeof(entry
->target
));
415 changed
|= odhcp6c_update_entry(STATE_RA_DNS
, entry
, 0, true);
417 } else if (opt
->type
== ND_OPT_DNSSL
&& opt
->len
> 1) {
418 uint32_t *valid
= (uint32_t*)&opt
->data
[2];
419 uint8_t *buf
= &opt
->data
[6];
420 uint8_t *end
= &buf
[(opt
->len
- 1) * 8];
422 entry
->router
= from
.sin6_addr
;
423 entry
->valid
= ntohl(*valid
);
426 int len
= dn_expand(buf
, end
, buf
, (char*)entry
->auxtarget
, 256);
431 entry
->auxlen
= strlen((char*)entry
->auxtarget
);
433 if (entry
->auxlen
== 0)
436 changed
|= odhcp6c_update_entry(STATE_RA_SEARCH
, entry
, 0, true);
442 int states
[2] = {STATE_RA_DNS
, STATE_RA_SEARCH
};
443 for (size_t i
= 0; i
< 2; ++i
) {
445 uint8_t *start
= odhcp6c_get_state(states
[i
], &ra_dns_len
);
446 for (struct odhcp6c_entry
*c
= (struct odhcp6c_entry
*)start
;
447 (uint8_t*)c
< &start
[ra_dns_len
] && &c
->auxtarget
[c
->auxlen
] <= &start
[ra_dns_len
];
448 c
= (struct odhcp6c_entry
*)(&c
->auxtarget
[c
->auxlen
]))
449 if (IN6_ARE_ADDR_EQUAL(&c
->router
, &from
.sin6_addr
) &&
450 c
->valid
> router_valid
)
451 c
->valid
= router_valid
;
458 return found
&& changed
;