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.
26 #include <arpa/inet.h>
27 #include <sys/socket.h>
28 #include <sys/types.h>
29 #include <netinet/in.h>
30 #include <netinet/icmp6.h>
32 #include <linux/rtnetlink.h>
35 #define SOL_NETLINK 270
38 #ifndef NETLINK_ADD_MEMBERSHIP
39 #define NETLINK_ADD_MEMBERSHIP 1
43 #define IFF_LOWER_UP 0x10000
50 static bool nocarrier
= false;
52 static int sock
= -1, rtnl
= -1;
53 static int if_index
= 0;
54 static char if_name
[IF_NAMESIZE
] = {0};
55 static volatile int rs_attempt
= 0;
56 static struct in6_addr lladdr
= IN6ADDR_ANY_INIT
;
58 static void ra_send_rs(int signal
__attribute__((unused
)));
60 int ra_init(const char *ifname
, const struct in6_addr
*ifid
)
62 const pid_t ourpid
= getpid();
63 sock
= socket(AF_INET6
, SOCK_RAW
| SOCK_CLOEXEC
, IPPROTO_ICMPV6
);
67 if_index
= if_nametoindex(ifname
);
71 strncpy(if_name
, ifname
, sizeof(if_name
) - 1);
74 rtnl
= socket(AF_NETLINK
, SOCK_DGRAM
| SOCK_CLOEXEC
, NETLINK_ROUTE
);
78 struct sockaddr_nl rtnl_kernel
= { .nl_family
= AF_NETLINK
};
79 if (connect(rtnl
, (const struct sockaddr
*)&rtnl_kernel
, sizeof(rtnl_kernel
)) < 0)
82 int val
= RTNLGRP_LINK
;
83 setsockopt(rtnl
, SOL_NETLINK
, NETLINK_ADD_MEMBERSHIP
, &val
, sizeof(val
));
84 fcntl(rtnl
, F_SETOWN
, ourpid
);
85 fcntl(rtnl
, F_SETFL
, fcntl(sock
, F_GETFL
) | O_ASYNC
);
91 .hdr
= {sizeof(req
), RTM_GETLINK
, NLM_F_REQUEST
, 1, 0},
92 .ifi
= {.ifi_index
= if_index
}
94 send(rtnl
, &req
, sizeof(req
), 0);
96 // Filter ICMPv6 package types
97 struct icmp6_filter filt
;
98 ICMP6_FILTER_SETBLOCKALL(&filt
);
99 ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT
, &filt
);
100 setsockopt(sock
, IPPROTO_ICMPV6
, ICMP6_FILTER
, &filt
, sizeof(filt
));
103 struct ipv6_mreq an
= {ALL_IPV6_NODES
, if_index
};
104 setsockopt(sock
, IPPROTO_IPV6
, IPV6_ADD_MEMBERSHIP
, &an
, sizeof(an
));
106 // Let the kernel compute our checksums
108 setsockopt(sock
, IPPROTO_RAW
, IPV6_CHECKSUM
, &val
, sizeof(val
));
110 // This is required by RFC 4861
112 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
));
114 // Receive multicast hops
116 setsockopt(sock
, IPPROTO_IPV6
, IPV6_RECVHOPLIMIT
, &val
, sizeof(val
));
118 // Bind to one device
119 setsockopt(sock
, SOL_SOCKET
, SO_BINDTODEVICE
, ifname
, strlen(ifname
));
122 fcntl(sock
, F_SETOWN
, ourpid
);
123 fcntl(sock
, F_SETFL
, fcntl(sock
, F_GETFL
) | O_ASYNC
);
126 signal(SIGALRM
, ra_send_rs
);
133 static void ra_send_rs(int signal
__attribute__((unused
)))
135 const struct icmp6_hdr rs
= {ND_ROUTER_SOLICIT
, 0, 0, {{0}}};
136 const struct sockaddr_in6 dest
= {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, if_index
};
137 sendto(sock
, &rs
, sizeof(rs
), MSG_DONTWAIT
, (struct sockaddr
*)&dest
, sizeof(dest
));
139 if (++rs_attempt
<= 3)
144 static int16_t pref_to_priority(uint8_t flags
)
146 flags
= (flags
>> 3) & 0x03;
147 return (flags
== 0x0) ? 1024 : (flags
== 0x1) ? 512 :
148 (flags
== 0x3) ? 2048 : -1;
152 static void update_proc(const char *sect
, const char *opt
, uint32_t value
)
155 snprintf(buf
, sizeof(buf
), "/proc/sys/net/ipv6/%s/%s/%s", sect
, if_name
, opt
);
157 int fd
= open(buf
, O_WRONLY
);
158 write(fd
, buf
, snprintf(buf
, sizeof(buf
), "%u", value
));
163 bool ra_link_up(void)
165 static bool firstcall
= true;
168 struct ifinfomsg msg
;
176 read
= recv(rtnl
, &resp
, sizeof(resp
), MSG_DONTWAIT
);
177 if (read
< 0 || !NLMSG_OK(&resp
.hdr
, (size_t)read
) ||
178 resp
.hdr
.nlmsg_type
!= RTM_NEWLINK
||
179 resp
.msg
.ifi_index
!= if_index
)
182 bool hascarrier
= resp
.msg
.ifi_flags
& IFF_LOWER_UP
;
183 if (!firstcall
&& nocarrier
!= !hascarrier
)
186 nocarrier
= !hascarrier
;
191 syslog(LOG_NOTICE
, "carrier => %i event on %s", (int)!nocarrier
, if_name
);
200 static bool ra_icmpv6_valid(struct sockaddr_in6
*source
, int hlim
, uint8_t *data
, size_t len
)
202 struct icmp6_hdr
*hdr
= (struct icmp6_hdr
*)data
;
203 struct icmpv6_opt
*opt
, *end
= (struct icmpv6_opt
*)&data
[len
];
205 if (hlim
!= 255 || len
< sizeof(*hdr
) || hdr
->icmp6_code
)
208 switch (hdr
->icmp6_type
) {
209 case ND_ROUTER_ADVERT
:
210 if (!IN6_IS_ADDR_LINKLOCAL(&source
->sin6_addr
))
213 opt
= (struct icmpv6_opt
*)((struct nd_router_advert
*)data
+ 1);
220 icmpv6_for_each_option(opt
, opt
, end
)
226 bool ra_process(void)
229 bool changed
= false;
230 bool has_lladdr
= !IN6_IS_ADDR_UNSPECIFIED(&lladdr
);
231 uint8_t buf
[1500], cmsg_buf
[128];
232 struct nd_router_advert
*adv
= (struct nd_router_advert
*)buf
;
233 struct odhcp6c_entry entry
= {IN6ADDR_ANY_INIT
, 0, 0, IN6ADDR_ANY_INIT
, 0, 0, 0, 0, 0, 0};
234 const struct in6_addr any
= IN6ADDR_ANY_INIT
;
237 // Autodetect interface-id if not specified
238 struct ifaddrs
*ifaddr
, *ifa
;
240 if (getifaddrs(&ifaddr
) == 0) {
241 for (ifa
= ifaddr
; ifa
!= NULL
; ifa
= ifa
->ifa_next
) {
242 struct sockaddr_in6
*addr
;
244 if (ifa
->ifa_addr
== NULL
|| ifa
->ifa_addr
->sa_family
!= AF_INET6
)
247 addr
= (struct sockaddr_in6
*)ifa
->ifa_addr
;
249 if (!IN6_IS_ADDR_LINKLOCAL(&addr
->sin6_addr
))
252 if (!strcmp(ifa
->ifa_name
, if_name
)) {
253 lladdr
= addr
->sin6_addr
;
264 struct sockaddr_in6 from
;
265 struct iovec iov
= {buf
, sizeof(buf
)};
266 struct msghdr msg
= {&from
, sizeof(from
), &iov
, 1,
267 cmsg_buf
, sizeof(cmsg_buf
), 0};
269 ssize_t len
= recvmsg(sock
, &msg
, MSG_DONTWAIT
);
277 for (struct cmsghdr
*ch
= CMSG_FIRSTHDR(&msg
); ch
!= NULL
;
278 ch
= CMSG_NXTHDR(&msg
, ch
))
279 if (ch
->cmsg_level
== IPPROTO_IPV6
&&
280 ch
->cmsg_type
== IPV6_HOPLIMIT
)
281 memcpy(&hlim
, CMSG_DATA(ch
), sizeof(hlim
));
283 if (!ra_icmpv6_valid(&from
, hlim
, buf
, len
))
286 // Stop sending solicits
287 if (rs_attempt
> 0) {
296 uint32_t router_valid
= ntohs(adv
->nd_ra_router_lifetime
);
298 // Parse default route
301 entry
.router
= from
.sin6_addr
;
302 entry
.priority
= pref_to_priority(adv
->nd_ra_flags_reserved
);
303 if (entry
.priority
< 0)
304 entry
.priority
= pref_to_priority(0);
305 entry
.valid
= router_valid
;
306 entry
.preferred
= entry
.valid
;
307 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, &entry
);
310 if (adv
->nd_ra_curhoplimit
)
311 update_proc("conf", "hop_limit", adv
->nd_ra_curhoplimit
);
313 // Parse ND parameters
314 uint32_t reachable
= ntohl(adv
->nd_ra_reachable
);
315 if (reachable
> 0 && reachable
<= 3600000)
316 update_proc("neigh", "base_reachable_time_ms", reachable
);
318 uint32_t retransmit
= ntohl(adv
->nd_ra_retransmit
);
319 if (retransmit
> 0 && retransmit
<= 60000)
320 update_proc("neigh", "retrans_time_ms", retransmit
);
324 struct icmpv6_opt
*opt
;
325 icmpv6_for_each_option(opt
, &adv
[1], &buf
[len
]) {
326 if (opt
->type
== ND_OPT_MTU
) {
327 uint32_t *mtu
= (uint32_t*)&opt
->data
[2];
328 if (ntohl(*mtu
) >= 1280 && ntohl(*mtu
) <= 65535)
329 update_proc("conf", "mtu", ntohl(*mtu
));
330 } else if (opt
->type
== ND_OPT_ROUTE_INFORMATION
&& opt
->len
<= 3) {
331 entry
.router
= from
.sin6_addr
;
333 entry
.priority
= pref_to_priority(opt
->data
[1]);
334 entry
.length
= opt
->data
[0];
335 uint32_t *valid
= (uint32_t*)&opt
->data
[2];
336 entry
.valid
= ntohl(*valid
);
337 memcpy(&entry
.target
, &opt
->data
[6], (opt
->len
- 1) * 8);
339 if (entry
.length
> 128 || IN6_IS_ADDR_LINKLOCAL(&entry
.target
)
340 || IN6_IS_ADDR_LOOPBACK(&entry
.target
)
341 || IN6_IS_ADDR_MULTICAST(&entry
.target
))
344 if (entry
.priority
> 0)
345 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, &entry
);
346 } else if (opt
->type
== ND_OPT_PREFIX_INFORMATION
&& opt
->len
== 4) {
347 struct nd_opt_prefix_info
*pinfo
= (struct nd_opt_prefix_info
*)opt
;
349 entry
.target
= pinfo
->nd_opt_pi_prefix
;
350 entry
.priority
= 256;
351 entry
.length
= pinfo
->nd_opt_pi_prefix_len
;
352 entry
.valid
= ntohl(pinfo
->nd_opt_pi_valid_time
);
353 entry
.preferred
= ntohl(pinfo
->nd_opt_pi_preferred_time
);
355 if (entry
.length
> 128 || IN6_IS_ADDR_LINKLOCAL(&entry
.target
)
356 || IN6_IS_ADDR_LOOPBACK(&entry
.target
)
357 || IN6_IS_ADDR_MULTICAST(&entry
.target
)
358 || entry
.valid
< entry
.preferred
)
361 if (pinfo
->nd_opt_pi_flags_reserved
& ND_OPT_PI_FLAG_ONLINK
)
362 changed
|= odhcp6c_update_entry_safe(STATE_RA_ROUTE
, &entry
, 7200);
364 if (!(pinfo
->nd_opt_pi_flags_reserved
& ND_OPT_PI_FLAG_AUTO
) ||
365 pinfo
->nd_opt_pi_prefix_len
!= 64)
368 entry
.target
.s6_addr32
[2] = lladdr
.s6_addr32
[2];
369 entry
.target
.s6_addr32
[3] = lladdr
.s6_addr32
[3];
371 changed
|= odhcp6c_update_entry_safe(STATE_RA_PREFIX
, &entry
, 7200);
372 } else if (opt
->type
== ND_OPT_RECURSIVE_DNS
&& opt
->len
> 2) {
373 entry
.router
= from
.sin6_addr
;
376 uint32_t *valid
= (uint32_t*)&opt
->data
[2];
377 entry
.valid
= ntohl(*valid
);
380 for (ssize_t i
= 0; i
< (opt
->len
- 1) / 2; ++i
) {
381 memcpy(&entry
.target
, &opt
->data
[6 + i
* sizeof(entry
.target
)],
382 sizeof(entry
.target
));
383 changed
|= odhcp6c_update_entry(STATE_RA_DNS
, &entry
);
389 struct odhcp6c_entry
*entry
= odhcp6c_get_state(STATE_RA_DNS
, &ra_dns_len
);
390 for (size_t i
= 0; i
< ra_dns_len
/ sizeof(*entry
); ++i
)
391 if (IN6_ARE_ADDR_EQUAL(&entry
[i
].router
, &from
.sin6_addr
) &&
392 entry
[i
].valid
> router_valid
)
393 entry
[i
].valid
= router_valid
;
399 return found
&& changed
;