2 * Copyright (C) 2012-2013 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 <netinet/in.h>
28 #include <netinet/icmp6.h>
30 #include <linux/rtnetlink.h>
33 #define SOL_NETLINK 270
36 #ifndef NETLINK_ADD_MEMBERSHIP
37 #define NETLINK_ADD_MEMBERSHIP 1
41 #define IFF_LOWER_UP 0x10000
48 static bool nocarrier
= false;
50 static int sock
= -1, rtnl
= -1;
51 static int if_index
= 0;
52 static char if_name
[IF_NAMESIZE
] = {0};
53 static volatile int rs_attempt
= 0;
54 static struct in6_addr lladdr
= IN6ADDR_ANY_INIT
;
56 static void ra_send_rs(int signal
__attribute__((unused
)));
58 int ra_init(const char *ifname
, const struct in6_addr
*ifid
)
60 const pid_t ourpid
= getpid();
61 sock
= socket(AF_INET6
, SOCK_RAW
| SOCK_CLOEXEC
, IPPROTO_ICMPV6
);
65 if_index
= if_nametoindex(ifname
);
69 strncpy(if_name
, ifname
, sizeof(if_name
) - 1);
72 rtnl
= socket(AF_NETLINK
, SOCK_DGRAM
| SOCK_CLOEXEC
, NETLINK_ROUTE
);
76 struct sockaddr_nl rtnl_kernel
= { .nl_family
= AF_NETLINK
};
77 if (connect(rtnl
, (const struct sockaddr
*)&rtnl_kernel
, sizeof(rtnl_kernel
)) < 0)
80 int val
= RTNLGRP_LINK
;
81 setsockopt(rtnl
, SOL_NETLINK
, NETLINK_ADD_MEMBERSHIP
, &val
, sizeof(val
));
82 fcntl(rtnl
, F_SETOWN
, ourpid
);
83 fcntl(rtnl
, F_SETFL
, fcntl(sock
, F_GETFL
) | O_ASYNC
);
89 .hdr
= {sizeof(req
), RTM_GETLINK
, NLM_F_REQUEST
, 1, 0},
90 .ifi
= {.ifi_index
= if_index
}
92 send(rtnl
, &req
, sizeof(req
), 0);
94 // Filter ICMPv6 package types
95 struct icmp6_filter filt
;
96 ICMP6_FILTER_SETBLOCKALL(&filt
);
97 ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT
, &filt
);
98 setsockopt(sock
, IPPROTO_ICMPV6
, ICMP6_FILTER
, &filt
, sizeof(filt
));
101 struct ipv6_mreq an
= {ALL_IPV6_NODES
, if_index
};
102 setsockopt(sock
, IPPROTO_IPV6
, IPV6_ADD_MEMBERSHIP
, &an
, sizeof(an
));
104 // Let the kernel compute our checksums
106 setsockopt(sock
, IPPROTO_RAW
, IPV6_CHECKSUM
, &val
, sizeof(val
));
108 // This is required by RFC 4861
110 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
));
112 // Receive multicast hops
114 setsockopt(sock
, IPPROTO_IPV6
, IPV6_RECVHOPLIMIT
, &val
, sizeof(val
));
116 // Bind to one device
117 setsockopt(sock
, SOL_SOCKET
, SO_BINDTODEVICE
, ifname
, strlen(ifname
));
120 fcntl(sock
, F_SETOWN
, ourpid
);
121 fcntl(sock
, F_SETFL
, fcntl(sock
, F_GETFL
) | O_ASYNC
);
124 signal(SIGALRM
, ra_send_rs
);
131 static void ra_send_rs(int signal
__attribute__((unused
)))
133 const struct icmp6_hdr rs
= {ND_ROUTER_SOLICIT
, 0, 0, {{0}}};
134 const struct sockaddr_in6 dest
= {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, if_index
};
135 sendto(sock
, &rs
, sizeof(rs
), MSG_DONTWAIT
, (struct sockaddr
*)&dest
, sizeof(dest
));
137 if (++rs_attempt
<= 3)
142 static int16_t pref_to_priority(uint8_t flags
)
144 flags
= (flags
>> 3) & 0x03;
145 return (flags
== 0x0) ? 1024 : (flags
== 0x1) ? 512 :
146 (flags
== 0x3) ? 2048 : -1;
150 static void update_proc(const char *sect
, const char *opt
, uint32_t value
)
153 snprintf(buf
, sizeof(buf
), "/proc/sys/net/ipv6/%s/%s/%s", sect
, if_name
, opt
);
155 int fd
= open(buf
, O_WRONLY
);
156 write(fd
, buf
, snprintf(buf
, sizeof(buf
), "%u", value
));
161 bool ra_link_up(void)
163 static bool firstcall
= true;
166 struct ifinfomsg msg
;
174 read
= recv(rtnl
, &resp
, sizeof(resp
), MSG_DONTWAIT
);
175 if (read
< 0 || !NLMSG_OK(&resp
.hdr
, (size_t)read
) ||
176 resp
.hdr
.nlmsg_type
!= RTM_NEWLINK
||
177 resp
.msg
.ifi_index
!= if_index
)
180 bool hascarrier
= resp
.msg
.ifi_flags
& IFF_LOWER_UP
;
181 if (!firstcall
&& nocarrier
!= !hascarrier
)
184 nocarrier
= !hascarrier
;
189 syslog(LOG_NOTICE
, "carrier => %i event on %s", (int)!nocarrier
, if_name
);
198 static int ra_icmpv6_valid(struct sockaddr_in6
*source
, int hlim
, uint8_t *data
, size_t len
)
200 struct icmp6_hdr
*hdr
= (struct icmp6_hdr
*)data
;
201 struct icmpv6_opt
*opt
;
207 if (len
< sizeof(*hdr
))
213 switch (hdr
->icmp6_type
) {
214 case ND_ROUTER_ADVERT
:
215 if (!IN6_IS_ADDR_LINKLOCAL(&source
->sin6_addr
))
218 opt
= (struct icmpv6_opt
*)((struct nd_router_advert
*)data
+ 1);
219 optlen
= len
- sizeof(struct nd_router_advert
);
227 size_t l
= opt
->len
<< 3;
229 if (optlen
< sizeof(*opt
))
232 if (l
> optlen
|| l
== 0)
235 opt
= (struct icmpv6_opt
*)(((uint8_t *)opt
) + l
);
243 bool ra_process(void)
246 bool changed
= false;
247 uint8_t buf
[1500], cmsg_buf
[128];
248 struct nd_router_advert
*adv
= (struct nd_router_advert
*)buf
;
249 struct odhcp6c_entry entry
= {IN6ADDR_ANY_INIT
, 0, 0, IN6ADDR_ANY_INIT
, 0, 0, 0, 0, 0};
250 const struct in6_addr any
= IN6ADDR_ANY_INIT
;
252 if (IN6_IS_ADDR_UNSPECIFIED(&lladdr
)) {
253 // Autodetect interface-id if not specified
254 FILE *fp
= fopen("/proc/net/if_inet6", "r");
256 char addrbuf
[33], ifbuf
[16];
257 while (fscanf(fp
, "%32s %*x %*x %*x %*x %15s", addrbuf
, ifbuf
) == 2) {
258 if (!strcmp(ifbuf
, if_name
)) {
259 script_unhexlify((uint8_t*)&lladdr
, sizeof(lladdr
), addrbuf
);
268 struct sockaddr_in6 from
;
269 struct iovec iov
= {buf
, sizeof(buf
)};
270 struct msghdr msg
= {&from
, sizeof(from
), &iov
, 1,
271 cmsg_buf
, sizeof(cmsg_buf
), 0};
273 ssize_t len
= recvmsg(sock
, &msg
, MSG_DONTWAIT
);
278 for (struct cmsghdr
*ch
= CMSG_FIRSTHDR(&msg
); ch
!= NULL
;
279 ch
= CMSG_NXTHDR(&msg
, ch
))
280 if (ch
->cmsg_level
== IPPROTO_IPV6
&&
281 ch
->cmsg_type
== IPV6_HOPLIMIT
)
282 memcpy(&hlim
, CMSG_DATA(ch
), sizeof(hlim
));
284 if (!ra_icmpv6_valid(&from
, hlim
, buf
, len
))
287 // Stop sending solicits
288 if (rs_attempt
> 0) {
297 uint32_t router_valid
= ntohs(adv
->nd_ra_router_lifetime
);
299 // Parse default route
302 entry
.router
= from
.sin6_addr
;
303 entry
.priority
= pref_to_priority(adv
->nd_ra_flags_reserved
);
304 if (entry
.priority
< 0)
305 entry
.priority
= pref_to_priority(0);
306 entry
.valid
= router_valid
;
307 entry
.preferred
= entry
.valid
;
308 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, &entry
);
311 if (adv
->nd_ra_curhoplimit
)
312 update_proc("conf", "hop_limit", adv
->nd_ra_curhoplimit
);
314 // Parse ND parameters
315 if (ntohl(adv
->nd_ra_reachable
) <= 3600000)
316 update_proc("neigh", "base_reachable_time_ms", ntohl(adv
->nd_ra_reachable
));
318 if (ntohl(adv
->nd_ra_retransmit
) <= 60000)
319 update_proc("neigh", "retrans_time_ms", ntohl(adv
->nd_ra_retransmit
));
323 struct icmpv6_opt
*opt
;
324 icmpv6_for_each_option(opt
, &adv
[1], &buf
[len
]) {
325 if (opt
->type
== ND_OPT_MTU
) {
326 struct nd_opt_mtu
*mtu
= (struct nd_opt_mtu
*)opt
;
327 if (ntohl(mtu
->nd_opt_mtu_mtu
) >= 1280 && ntohl(mtu
->nd_opt_mtu_mtu
) <= 65535)
328 update_proc("conf", "mtu", ntohl(mtu
->nd_opt_mtu_mtu
));
329 } else if (opt
->type
== ND_OPT_ROUTE_INFORMATION
&& opt
->len
<= 3) {
330 struct nd_opt_route_info
*rinfo
= (struct nd_opt_route_info
*)opt
;
331 entry
.router
= from
.sin6_addr
;
333 entry
.priority
= pref_to_priority(rinfo
->nd_opt_ri_prf
);
334 entry
.length
= rinfo
->nd_opt_ri_prefix_len
;
335 entry
.valid
= ntohl(rinfo
->nd_opt_ri_route_lifetime
);
336 memcpy(&entry
.target
, &rinfo
->nd_opt_ri_prefix
[0], (rinfo
->nd_opt_ri_len
- 1) * 8);
338 if (entry
.length
> 128 || IN6_IS_ADDR_LINKLOCAL(&entry
.target
)
339 || IN6_IS_ADDR_LOOPBACK(&entry
.target
)
340 || IN6_IS_ADDR_MULTICAST(&entry
.target
))
343 if (entry
.priority
> 0)
344 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, &entry
);
345 } else if (opt
->type
== ND_OPT_PREFIX_INFORMATION
&& opt
->len
== 4) {
346 struct nd_opt_prefix_info
*pinfo
= (struct nd_opt_prefix_info
*)opt
;
348 entry
.target
= pinfo
->nd_opt_pi_prefix
;
349 entry
.priority
= 256;
350 entry
.length
= pinfo
->nd_opt_pi_prefix_len
;
351 entry
.valid
= ntohl(pinfo
->nd_opt_pi_valid_time
);
352 entry
.preferred
= ntohl(pinfo
->nd_opt_pi_preferred_time
);
354 if (entry
.length
> 128 || IN6_IS_ADDR_LINKLOCAL(&entry
.target
)
355 || IN6_IS_ADDR_LOOPBACK(&entry
.target
)
356 || IN6_IS_ADDR_MULTICAST(&entry
.target
)
357 || entry
.valid
< entry
.preferred
)
360 if (pinfo
->nd_opt_pi_flags_reserved
& ND_OPT_PI_FLAG_ONLINK
)
361 changed
|= odhcp6c_update_entry_safe(STATE_RA_ROUTE
, &entry
, 7200);
363 if (!(pinfo
->nd_opt_pi_flags_reserved
& ND_OPT_PI_FLAG_AUTO
) ||
364 pinfo
->nd_opt_pi_prefix_len
!= 64)
367 entry
.target
.s6_addr32
[2] = lladdr
.s6_addr32
[2];
368 entry
.target
.s6_addr32
[3] = lladdr
.s6_addr32
[3];
370 changed
|= odhcp6c_update_entry_safe(STATE_RA_PREFIX
, &entry
, 7200);
371 } else if (opt
->type
== ND_OPT_RECURSIVE_DNS
&& opt
->len
> 2) {
372 struct nd_opt_recursive_dns
*rdns
= (struct nd_opt_recursive_dns
*)opt
;
373 entry
.router
= from
.sin6_addr
;
376 entry
.valid
= ntohl(rdns
->lifetime
);
379 for (ssize_t i
= 0; i
< (opt
->len
- 1) / 2; ++i
) {
380 memcpy(&entry
.target
, &rdns
->servers
[i
],
381 sizeof(entry
.target
));
382 changed
|= odhcp6c_update_entry(STATE_RA_DNS
, &entry
);
388 struct odhcp6c_entry
*entry
= odhcp6c_get_state(STATE_RA_DNS
, &ra_dns_len
);
389 for (size_t i
= 0; i
< ra_dns_len
/ sizeof(*entry
); ++i
)
390 if (IN6_ARE_ADDR_EQUAL(&entry
[i
].router
, &from
.sin6_addr
) &&
391 entry
[i
].valid
> router_valid
)
392 entry
[i
].valid
= router_valid
;
398 return found
&& changed
;