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
);
62 if_index
= if_nametoindex(ifname
);
63 strncpy(if_name
, ifname
, sizeof(if_name
) - 1);
66 rtnl
= socket(AF_NETLINK
, SOCK_DGRAM
| SOCK_CLOEXEC
, NETLINK_ROUTE
);
67 struct sockaddr_nl rtnl_kernel
= { .nl_family
= AF_NETLINK
};
68 connect(rtnl
, (const struct sockaddr
*)&rtnl_kernel
, sizeof(rtnl_kernel
));
70 int val
= RTNLGRP_LINK
;
71 setsockopt(rtnl
, SOL_NETLINK
, NETLINK_ADD_MEMBERSHIP
, &val
, sizeof(val
));
72 fcntl(rtnl
, F_SETOWN
, ourpid
);
73 fcntl(rtnl
, F_SETFL
, fcntl(sock
, F_GETFL
) | O_ASYNC
);
79 .hdr
= {sizeof(req
), RTM_GETLINK
, NLM_F_REQUEST
, 1, 0},
80 .ifi
= {.ifi_index
= if_index
}
82 send(rtnl
, &req
, sizeof(req
), 0);
84 // Filter ICMPv6 package types
85 struct icmp6_filter filt
;
86 ICMP6_FILTER_SETBLOCKALL(&filt
);
87 ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT
, &filt
);
88 setsockopt(sock
, IPPROTO_ICMPV6
, ICMP6_FILTER
, &filt
, sizeof(filt
));
91 struct ipv6_mreq an
= {ALL_IPV6_NODES
, if_index
};
92 setsockopt(sock
, IPPROTO_IPV6
, IPV6_ADD_MEMBERSHIP
, &an
, sizeof(an
));
94 // Let the kernel compute our checksums
96 setsockopt(sock
, IPPROTO_RAW
, IPV6_CHECKSUM
, &val
, sizeof(val
));
98 // This is required by RFC 4861
100 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
));
102 // Receive multicast hops
104 setsockopt(sock
, IPPROTO_IPV6
, IPV6_RECVHOPLIMIT
, &val
, sizeof(val
));
106 // Bind to one device
107 setsockopt(sock
, SOL_SOCKET
, SO_BINDTODEVICE
, ifname
, strlen(ifname
));
110 fcntl(sock
, F_SETOWN
, ourpid
);
111 fcntl(sock
, F_SETFL
, fcntl(sock
, F_GETFL
) | O_ASYNC
);
114 signal(SIGALRM
, ra_send_rs
);
121 static void ra_send_rs(int signal
__attribute__((unused
)))
123 const struct icmp6_hdr rs
= {ND_ROUTER_SOLICIT
, 0, 0, {{0}}};
124 const struct sockaddr_in6 dest
= {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, if_index
};
125 sendto(sock
, &rs
, sizeof(rs
), MSG_DONTWAIT
, (struct sockaddr
*)&dest
, sizeof(dest
));
127 if (++rs_attempt
<= 3)
132 static int16_t pref_to_priority(uint8_t flags
)
134 flags
= (flags
>> 3) & 0x03;
135 return (flags
== 0x0) ? 1024 : (flags
== 0x1) ? 512 :
136 (flags
== 0x3) ? 2048 : -1;
140 static void update_proc(const char *sect
, const char *opt
, uint32_t value
)
143 snprintf(buf
, sizeof(buf
), "/proc/sys/net/ipv6/%s/%s/%s", sect
, if_name
, opt
);
145 int fd
= open(buf
, O_WRONLY
);
146 write(fd
, buf
, snprintf(buf
, sizeof(buf
), "%u", value
));
151 bool ra_link_up(void)
155 struct ifinfomsg msg
;
163 read
= recv(rtnl
, &resp
, sizeof(resp
), MSG_DONTWAIT
);
164 if (read
< 0 || !NLMSG_OK(&resp
.hdr
, (size_t)read
) ||
165 resp
.hdr
.nlmsg_type
!= RTM_NEWLINK
||
166 resp
.msg
.ifi_index
!= if_index
)
169 bool hascarrier
= resp
.msg
.ifi_flags
& IFF_LOWER_UP
;
170 if (nocarrier
&& hascarrier
)
173 nocarrier
= !hascarrier
;
177 syslog(LOG_NOTICE
, "carrier up event on %s", if_name
);
185 bool ra_process(void)
188 bool changed
= false;
189 uint8_t buf
[1500], cmsg_buf
[128];
190 struct nd_router_advert
*adv
= (struct nd_router_advert
*)buf
;
191 struct odhcp6c_entry entry
= {IN6ADDR_ANY_INIT
, 0, 0, IN6ADDR_ANY_INIT
, 0, 0, 0, 0, 0};
192 const struct in6_addr any
= IN6ADDR_ANY_INIT
;
194 if (IN6_IS_ADDR_UNSPECIFIED(&lladdr
)) {
195 // Autodetect interface-id if not specified
196 FILE *fp
= fopen("/proc/net/if_inet6", "r");
198 char addrbuf
[33], ifbuf
[16];
199 while (fscanf(fp
, "%32s %*x %*x %*x %*x %15s", addrbuf
, ifbuf
) == 2) {
200 if (!strcmp(ifbuf
, if_name
)) {
201 script_unhexlify((uint8_t*)&lladdr
, sizeof(lladdr
), addrbuf
);
210 struct sockaddr_in6 from
;
211 struct iovec iov
= {buf
, sizeof(buf
)};
212 struct msghdr msg
= {&from
, sizeof(from
), &iov
, 1,
213 cmsg_buf
, sizeof(cmsg_buf
), 0};
215 ssize_t len
= recvmsg(sock
, &msg
, MSG_DONTWAIT
);
218 else if (len
< (ssize_t
)sizeof(*adv
))
222 for (struct cmsghdr
*ch
= CMSG_FIRSTHDR(&msg
); ch
!= NULL
;
223 ch
= CMSG_NXTHDR(&msg
, ch
))
224 if (ch
->cmsg_level
== IPPROTO_IPV6
&&
225 ch
->cmsg_type
== IPV6_HOPLIMIT
)
226 memcpy(&hlim
, CMSG_DATA(ch
), sizeof(hlim
));
231 // Stop sending solicits
232 if (rs_attempt
> 0) {
241 uint32_t router_valid
= ntohs(adv
->nd_ra_router_lifetime
);
243 // Parse default route
246 entry
.router
= from
.sin6_addr
;
247 entry
.priority
= pref_to_priority(adv
->nd_ra_flags_reserved
);
248 if (entry
.priority
< 0)
249 entry
.priority
= pref_to_priority(0);
250 entry
.valid
= router_valid
;
251 entry
.preferred
= entry
.valid
;
252 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, &entry
);
254 // Parse ND parameters
255 if (ntohl(adv
->nd_ra_reachable
) <= 3600000)
256 update_proc("neigh", "base_reachable_time_ms", ntohl(adv
->nd_ra_reachable
));
258 if (ntohl(adv
->nd_ra_retransmit
) <= 60000)
259 update_proc("neigh", "retrans_time_ms", ntohl(adv
->nd_ra_retransmit
));
263 struct icmpv6_opt
*opt
;
264 icmpv6_for_each_option(opt
, &adv
[1], &buf
[len
]) {
265 if (opt
->type
== ND_OPT_MTU
) {
266 uint32_t *mtu
= (uint32_t*)&opt
->data
[2];
267 if (ntohl(*mtu
) >= 1280 && ntohl(*mtu
) <= 65535)
268 update_proc("conf", "mtu", ntohl(*mtu
));
269 } else if (opt
->type
== ND_OPT_ROUTE_INFORMATION
&& opt
->len
<= 3) {
270 entry
.router
= from
.sin6_addr
;
272 entry
.priority
= pref_to_priority(opt
->data
[1]);
273 entry
.length
= opt
->data
[0];
274 uint32_t *valid
= (uint32_t*)&opt
->data
[2];
275 entry
.valid
= ntohl(*valid
);
276 memcpy(&entry
.target
, &opt
->data
[6], (opt
->len
- 1) * 8);
278 if (entry
.length
> 128 || IN6_IS_ADDR_LINKLOCAL(&entry
.target
)
279 || IN6_IS_ADDR_LOOPBACK(&entry
.target
)
280 || IN6_IS_ADDR_MULTICAST(&entry
.target
))
283 if (entry
.priority
> 0)
284 changed
|= odhcp6c_update_entry(STATE_RA_ROUTE
, &entry
);
285 } else if (opt
->type
== ND_OPT_PREFIX_INFORMATION
&& opt
->len
== 4) {
286 struct nd_opt_prefix_info
*pinfo
= (struct nd_opt_prefix_info
*)opt
;
288 entry
.target
= pinfo
->nd_opt_pi_prefix
;
289 entry
.priority
= 256;
290 entry
.length
= pinfo
->nd_opt_pi_prefix_len
;
291 entry
.valid
= ntohl(pinfo
->nd_opt_pi_valid_time
);
292 entry
.preferred
= ntohl(pinfo
->nd_opt_pi_preferred_time
);
294 if (entry
.length
> 128 || IN6_IS_ADDR_LINKLOCAL(&entry
.target
)
295 || IN6_IS_ADDR_LOOPBACK(&entry
.target
)
296 || IN6_IS_ADDR_MULTICAST(&entry
.target
)
297 || entry
.valid
< entry
.preferred
)
300 if (pinfo
->nd_opt_pi_flags_reserved
& ND_OPT_PI_FLAG_ONLINK
)
301 changed
|= odhcp6c_update_entry_safe(STATE_RA_ROUTE
, &entry
, 7200);
303 if (!(pinfo
->nd_opt_pi_flags_reserved
& ND_OPT_PI_FLAG_AUTO
) ||
304 pinfo
->nd_opt_pi_prefix_len
!= 64)
307 entry
.target
.s6_addr32
[2] = lladdr
.s6_addr32
[2];
308 entry
.target
.s6_addr32
[3] = lladdr
.s6_addr32
[3];
310 changed
|= odhcp6c_update_entry_safe(STATE_RA_PREFIX
, &entry
, 7200);
311 } else if (opt
->type
== ND_OPT_RECURSIVE_DNS
&& opt
->len
> 2) {
312 entry
.router
= from
.sin6_addr
;
315 uint32_t *valid
= (uint32_t*)&opt
->data
[2];
316 entry
.valid
= ntohl(*valid
);
319 for (ssize_t i
= 0; i
< (opt
->len
- 1) / 2; ++i
) {
320 memcpy(&entry
.target
, &opt
->data
[6 + i
* sizeof(entry
.target
)],
321 sizeof(entry
.target
));
322 changed
|= odhcp6c_update_entry(STATE_RA_DNS
, &entry
);
328 struct odhcp6c_entry
*entry
= odhcp6c_get_state(STATE_RA_DNS
, &ra_dns_len
);
329 for (size_t i
= 0; i
< ra_dns_len
/ sizeof(*entry
); ++i
)
330 if (IN6_ARE_ADDR_EQUAL(&entry
[i
].router
, &from
.sin6_addr
) &&
331 entry
[i
].valid
> router_valid
)
332 entry
[i
].valid
= router_valid
;
338 return found
&& changed
;