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.
25 #include <arpa/inet.h>
26 #include <sys/socket.h>
27 #include <sys/types.h>
28 #include <netinet/in.h>
29 #include <netinet/icmp6.h>
31 #include <linux/rtnetlink.h>
34 #define SOL_NETLINK 270
37 #ifndef NETLINK_ADD_MEMBERSHIP
38 #define NETLINK_ADD_MEMBERSHIP 1
42 #define IFF_LOWER_UP 0x10000
49 static bool nocarrier
= false;
51 static int sock
= -1, rtnl
= -1;
52 static int if_index
= 0;
53 static char if_name
[IF_NAMESIZE
] = {0};
54 static volatile int rs_attempt
= 0;
55 static struct in6_addr lladdr
= IN6ADDR_ANY_INIT
;
59 struct icmpv6_opt lladdr
;
61 .hdr
= {ND_ROUTER_SOLICIT
, 0, 0, {{0}}},
62 .lladdr
= {ND_OPT_SOURCE_LINKADDR
, 1, {0}},
66 static void ra_send_rs(int signal
__attribute__((unused
)));
68 int ra_init(const char *ifname
, const struct in6_addr
*ifid
)
70 const pid_t ourpid
= getpid();
71 sock
= socket(AF_INET6
, SOCK_RAW
| SOCK_CLOEXEC
, IPPROTO_ICMPV6
);
75 if_index
= if_nametoindex(ifname
);
79 strncpy(if_name
, ifname
, sizeof(if_name
) - 1);
82 rtnl
= socket(AF_NETLINK
, SOCK_DGRAM
| SOCK_CLOEXEC
, NETLINK_ROUTE
);
86 struct sockaddr_nl rtnl_kernel
= { .nl_family
= AF_NETLINK
};
87 if (connect(rtnl
, (const struct sockaddr
*)&rtnl_kernel
, sizeof(rtnl_kernel
)) < 0)
90 int val
= RTNLGRP_LINK
;
91 setsockopt(rtnl
, SOL_NETLINK
, NETLINK_ADD_MEMBERSHIP
, &val
, sizeof(val
));
92 fcntl(rtnl
, F_SETOWN
, ourpid
);
93 fcntl(rtnl
, F_SETFL
, fcntl(sock
, F_GETFL
) | O_ASYNC
);
99 .hdr
= {sizeof(req
), RTM_GETLINK
, NLM_F_REQUEST
, 1, 0},
100 .ifi
= {.ifi_index
= if_index
}
102 send(rtnl
, &req
, sizeof(req
), 0);
105 // Filter ICMPv6 package types
106 struct icmp6_filter filt
;
107 ICMP6_FILTER_SETBLOCKALL(&filt
);
108 ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT
, &filt
);
109 setsockopt(sock
, IPPROTO_ICMPV6
, ICMP6_FILTER
, &filt
, sizeof(filt
));
112 struct ipv6_mreq an
= {ALL_IPV6_NODES
, if_index
};
113 setsockopt(sock
, IPPROTO_IPV6
, IPV6_ADD_MEMBERSHIP
, &an
, sizeof(an
));
115 // Let the kernel compute our checksums
117 setsockopt(sock
, IPPROTO_RAW
, IPV6_CHECKSUM
, &val
, sizeof(val
));
119 // This is required by RFC 4861
121 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
));
123 // Receive multicast hops
125 setsockopt(sock
, IPPROTO_IPV6
, IPV6_RECVHOPLIMIT
, &val
, sizeof(val
));
127 // Bind to one device
128 setsockopt(sock
, SOL_SOCKET
, SO_BINDTODEVICE
, ifname
, strlen(ifname
));
131 fcntl(sock
, F_SETOWN
, ourpid
);
132 fcntl(sock
, F_SETFL
, fcntl(sock
, F_GETFL
) | O_ASYNC
);
135 signal(SIGALRM
, ra_send_rs
);
142 static void ra_send_rs(int signal
__attribute__((unused
)))
144 const struct sockaddr_in6 dest
= {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, if_index
};
145 const struct icmpv6_opt llnull
= {ND_OPT_SOURCE_LINKADDR
, 1, {0}};
148 if ((rs_attempt
% 2 == 0) && memcmp(&rs
.lladdr
, &llnull
, sizeof(llnull
)))
151 len
= sizeof(struct icmp6_hdr
);
153 sendto(sock
, &rs
, len
, MSG_DONTWAIT
, (struct sockaddr
*)&dest
, sizeof(dest
));
155 if (++rs_attempt
<= 3)
160 static int16_t pref_to_priority(uint8_t flags
)
162 flags
= (flags
>> 3) & 0x03;
163 return (flags
== 0x0) ? 1024 : (flags
== 0x1) ? 512 :
164 (flags
== 0x3) ? 2048 : -1;
168 static void update_proc(const char *sect
, const char *opt
, uint32_t value
)
171 snprintf(buf
, sizeof(buf
), "/proc/sys/net/ipv6/%s/%s/%s", sect
, if_name
, opt
);
173 int fd
= open(buf
, O_WRONLY
);
174 write(fd
, buf
, snprintf(buf
, sizeof(buf
), "%u", value
));
179 bool ra_link_up(void)
181 static bool firstcall
= true;
184 struct ifinfomsg msg
;
192 read
= recv(rtnl
, &resp
, sizeof(resp
), MSG_DONTWAIT
);
193 if (read
< 0 || !NLMSG_OK(&resp
.hdr
, (size_t)read
) ||
194 resp
.hdr
.nlmsg_type
!= RTM_NEWLINK
||
195 resp
.msg
.ifi_index
!= if_index
)
198 ssize_t alen
= NLMSG_PAYLOAD(&resp
.hdr
, sizeof(resp
.msg
));
199 for (struct rtattr
*rta
= (struct rtattr
*)(resp
.pad
);
200 RTA_OK(rta
, alen
); rta
= RTA_NEXT(rta
, alen
)) {
201 if (rta
->rta_type
== IFLA_ADDRESS
&&
202 RTA_PAYLOAD(rta
) >= sizeof(rs
.lladdr
.data
))
203 memcpy(rs
.lladdr
.data
, RTA_DATA(rta
), sizeof(rs
.lladdr
.data
));
206 bool hascarrier
= resp
.msg
.ifi_flags
& IFF_LOWER_UP
;
207 if (!firstcall
&& nocarrier
!= !hascarrier
)
210 nocarrier
= !hascarrier
;
215 syslog(LOG_NOTICE
, "carrier => %i event on %s", (int)!nocarrier
, if_name
);
224 static bool ra_icmpv6_valid(struct sockaddr_in6
*source
, int hlim
, uint8_t *data
, size_t len
)
226 struct icmp6_hdr
*hdr
= (struct icmp6_hdr
*)data
;
227 struct icmpv6_opt
*opt
, *end
= (struct icmpv6_opt
*)&data
[len
];
229 if (hlim
!= 255 || len
< sizeof(*hdr
) || hdr
->icmp6_code
)
232 switch (hdr
->icmp6_type
) {
233 case ND_ROUTER_ADVERT
:
234 if (!IN6_IS_ADDR_LINKLOCAL(&source
->sin6_addr
))
237 opt
= (struct icmpv6_opt
*)((struct nd_router_advert
*)data
+ 1);
244 icmpv6_for_each_option(opt
, opt
, end
)
250 bool ra_process(void)
253 bool changed
= false;
254 uint8_t buf
[1500], cmsg_buf
[128];
255 struct nd_router_advert
*adv
= (struct nd_router_advert
*)buf
;
256 struct odhcp6c_entry entry
= {IN6ADDR_ANY_INIT
, 0, 0, IN6ADDR_ANY_INIT
, 0, 0, 0, 0, 0, 0};
257 const struct in6_addr any
= IN6ADDR_ANY_INIT
;
259 if (IN6_IS_ADDR_UNSPECIFIED(&lladdr
)) {
260 struct sockaddr_in6 addr
= {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, if_index
};
261 socklen_t alen
= sizeof(addr
);
262 int sock
= socket(AF_INET6
, SOCK_RAW
, IPPROTO_ICMPV6
);
264 if (!connect(sock
, (struct sockaddr
*)&addr
, sizeof(addr
)) &&
265 !getsockname(sock
, (struct sockaddr
*)&addr
, &alen
))
266 lladdr
= addr
.sin6_addr
;
272 struct sockaddr_in6 from
;
273 struct iovec iov
= {buf
, sizeof(buf
)};
274 struct msghdr msg
= {&from
, sizeof(from
), &iov
, 1,
275 cmsg_buf
, sizeof(cmsg_buf
), 0};
277 ssize_t len
= recvmsg(sock
, &msg
, MSG_DONTWAIT
);
281 if (IN6_IS_ADDR_UNSPECIFIED(&lladdr
))
285 for (struct cmsghdr
*ch
= CMSG_FIRSTHDR(&msg
); ch
!= NULL
;
286 ch
= CMSG_NXTHDR(&msg
, ch
))
287 if (ch
->cmsg_level
== IPPROTO_IPV6
&&
288 ch
->cmsg_type
== IPV6_HOPLIMIT
)
289 memcpy(&hlim
, CMSG_DATA(ch
), sizeof(hlim
));
291 if (!ra_icmpv6_valid(&from
, hlim
, buf
, len
))
294 // Stop sending solicits
295 if (rs_attempt
> 0) {
304 uint32_t router_valid
= ntohs(adv
->nd_ra_router_lifetime
);
306 // Parse default route
309 entry
.router
= from
.sin6_addr
;
310 entry
.priority
= pref_to_priority(adv
->nd_ra_flags_reserved
);
311 if (entry
.priority
< 0)
312 entry
.priority
= pref_to_priority(0);
313 entry
.valid
= router_valid
;
314 entry
.preferred
= entry
.valid
;
315 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, &entry
, 0, true);
318 if (adv
->nd_ra_curhoplimit
)
319 update_proc("conf", "hop_limit", adv
->nd_ra_curhoplimit
);
321 // Parse ND parameters
322 uint32_t reachable
= ntohl(adv
->nd_ra_reachable
);
323 if (reachable
> 0 && reachable
<= 3600000)
324 update_proc("neigh", "base_reachable_time_ms", reachable
);
326 uint32_t retransmit
= ntohl(adv
->nd_ra_retransmit
);
327 if (retransmit
> 0 && retransmit
<= 60000)
328 update_proc("neigh", "retrans_time_ms", retransmit
);
332 struct icmpv6_opt
*opt
;
333 icmpv6_for_each_option(opt
, &adv
[1], &buf
[len
]) {
334 if (opt
->type
== ND_OPT_MTU
) {
335 uint32_t *mtu
= (uint32_t*)&opt
->data
[2];
336 if (ntohl(*mtu
) >= 1280 && ntohl(*mtu
) <= 65535)
337 update_proc("conf", "mtu", ntohl(*mtu
));
338 } else if (opt
->type
== ND_OPT_ROUTE_INFORMATION
&& opt
->len
<= 3) {
339 entry
.router
= from
.sin6_addr
;
341 entry
.priority
= pref_to_priority(opt
->data
[1]);
342 entry
.length
= opt
->data
[0];
343 uint32_t *valid
= (uint32_t*)&opt
->data
[2];
344 entry
.valid
= ntohl(*valid
);
345 memcpy(&entry
.target
, &opt
->data
[6], (opt
->len
- 1) * 8);
347 if (entry
.length
> 128 || IN6_IS_ADDR_LINKLOCAL(&entry
.target
)
348 || IN6_IS_ADDR_LOOPBACK(&entry
.target
)
349 || IN6_IS_ADDR_MULTICAST(&entry
.target
))
352 if (entry
.priority
> 0)
353 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, &entry
, 0, true);
354 } else if (opt
->type
== ND_OPT_PREFIX_INFORMATION
&& opt
->len
== 4) {
355 struct nd_opt_prefix_info
*pinfo
= (struct nd_opt_prefix_info
*)opt
;
357 entry
.target
= pinfo
->nd_opt_pi_prefix
;
358 entry
.priority
= 256;
359 entry
.length
= pinfo
->nd_opt_pi_prefix_len
;
360 entry
.valid
= ntohl(pinfo
->nd_opt_pi_valid_time
);
361 entry
.preferred
= ntohl(pinfo
->nd_opt_pi_preferred_time
);
363 if (entry
.length
> 128 || IN6_IS_ADDR_LINKLOCAL(&entry
.target
)
364 || IN6_IS_ADDR_LOOPBACK(&entry
.target
)
365 || IN6_IS_ADDR_MULTICAST(&entry
.target
)
366 || entry
.valid
< entry
.preferred
)
369 if (pinfo
->nd_opt_pi_flags_reserved
& ND_OPT_PI_FLAG_ONLINK
)
370 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, &entry
, 7200, true);
372 if (!(pinfo
->nd_opt_pi_flags_reserved
& ND_OPT_PI_FLAG_AUTO
) ||
373 pinfo
->nd_opt_pi_prefix_len
!= 64)
376 entry
.target
.s6_addr32
[2] = lladdr
.s6_addr32
[2];
377 entry
.target
.s6_addr32
[3] = lladdr
.s6_addr32
[3];
379 changed
|= odhcp6c_update_entry(STATE_RA_PREFIX
, &entry
, 7200, true);
380 } else if (opt
->type
== ND_OPT_RECURSIVE_DNS
&& opt
->len
> 2) {
381 entry
.router
= from
.sin6_addr
;
384 uint32_t *valid
= (uint32_t*)&opt
->data
[2];
385 entry
.valid
= ntohl(*valid
);
388 for (ssize_t i
= 0; i
< (opt
->len
- 1) / 2; ++i
) {
389 memcpy(&entry
.target
, &opt
->data
[6 + i
* sizeof(entry
.target
)],
390 sizeof(entry
.target
));
391 changed
|= odhcp6c_update_entry(STATE_RA_DNS
, &entry
, 0, true);
397 struct odhcp6c_entry
*entry
= odhcp6c_get_state(STATE_RA_DNS
, &ra_dns_len
);
398 for (size_t i
= 0; i
< ra_dns_len
/ sizeof(*entry
); ++i
)
399 if (IN6_ARE_ADDR_EQUAL(&entry
[i
].router
, &from
.sin6_addr
) &&
400 entry
[i
].valid
> router_valid
)
401 entry
[i
].valid
= router_valid
;
407 return found
&& changed
;