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>
37 static int sock
= -1, rtnl_sock
= -1;
38 static unsigned if_index
= 0;
39 static char if_name
[IF_NAMESIZE
] = {0};
40 static volatile int rs_attempt
= 0;
41 static struct in6_addr lladdr
= IN6ADDR_ANY_INIT
;
43 static void ra_send_rs(int signal
__attribute__((unused
)));
45 int ra_init(const char *ifname
, const struct in6_addr
*ifid
)
47 sock
= socket(AF_INET6
, SOCK_RAW
| SOCK_CLOEXEC
, IPPROTO_ICMPV6
);
48 if_index
= if_nametoindex(ifname
);
49 strncpy(if_name
, ifname
, sizeof(if_name
) - 1);
52 // Filter ICMPv6 package types
53 struct icmp6_filter filt
;
54 ICMP6_FILTER_SETBLOCKALL(&filt
);
55 ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT
, &filt
);
56 setsockopt(sock
, IPPROTO_ICMPV6
, ICMP6_FILTER
, &filt
, sizeof(filt
));
59 struct ipv6_mreq an
= {ALL_IPV6_NODES
, if_index
};
60 setsockopt(sock
, IPPROTO_IPV6
, IPV6_ADD_MEMBERSHIP
, &an
, sizeof(an
));
62 // Let the kernel compute our checksums
64 setsockopt(sock
, IPPROTO_RAW
, IPV6_CHECKSUM
, &val
, sizeof(val
));
66 // This is required by RFC 4861
68 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
));
71 setsockopt(sock
, SOL_SOCKET
, SO_BINDTODEVICE
, ifname
, strlen(ifname
));
74 const pid_t ourpid
= getpid();
75 fcntl(sock
, F_SETOWN
, ourpid
);
76 fcntl(sock
, F_SETFL
, fcntl(sock
, F_GETFL
) | O_ASYNC
);
78 if (IN6_IS_ADDR_UNSPECIFIED(&lladdr
)) {
79 // Autodetect interface-id if not specified
80 FILE *fp
= fopen("/proc/net/if_inet6", "r");
82 char addrbuf
[33], ifbuf
[16];
83 while (fscanf(fp
, "%32s %*x %*x %*x %*x %15s", addrbuf
, ifbuf
) == 2) {
84 if (!strcmp(ifbuf
, if_name
)) {
85 script_unhexlify((uint8_t*)&lladdr
, sizeof(lladdr
), addrbuf
);
93 // Open rtnetlink socket
94 rtnl_sock
= socket(AF_NETLINK
, SOCK_RAW
| SOCK_CLOEXEC
, NETLINK_ROUTE
);
95 struct sockaddr_nl rtnl_kernel
= { .nl_family
= AF_NETLINK
};
96 if (connect(rtnl_sock
, (struct sockaddr
*)&rtnl_kernel
, sizeof(rtnl_kernel
)))
98 uint32_t group
= RTNLGRP_IPV6_IFADDR
;
99 setsockopt(rtnl_sock
, SOL_NETLINK
, NETLINK_ADD_MEMBERSHIP
, &group
, sizeof(group
));
102 fcntl(rtnl_sock
, F_SETOWN
, ourpid
);
103 fcntl(rtnl_sock
, F_SETFL
, fcntl(rtnl_sock
, F_GETFL
) | O_ASYNC
);
106 signal(SIGALRM
, ra_send_rs
);
113 static void ra_send_rs(int signal
__attribute__((unused
)))
115 const struct icmp6_hdr rs
= {ND_ROUTER_SOLICIT
, 0, 0, {{0}}};
116 const struct sockaddr_in6 dest
= {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, if_index
};
117 sendto(sock
, &rs
, sizeof(rs
), MSG_DONTWAIT
, (struct sockaddr
*)&dest
, sizeof(dest
));
119 if (++rs_attempt
<= 3)
124 static int16_t pref_to_priority(uint8_t flags
)
126 flags
= (flags
>> 3) & 0x03;
127 return (flags
== 0x0) ? 1024 : (flags
== 0x1) ? 512 :
128 (flags
== 0x3) ? 2048 : -1;
132 static void update_proc(const char *sect
, const char *opt
, uint32_t value
)
135 snprintf(buf
, sizeof(buf
), "/proc/sys/net/ipv6/%s/%s/%s", sect
, if_name
, opt
);
137 int fd
= open(buf
, O_WRONLY
);
138 write(fd
, buf
, snprintf(buf
, sizeof(buf
), "%u", value
));
143 static bool ra_deduplicate(const struct in6_addr
*any
, uint8_t length
)
145 struct odhcp6c_entry entry
= {IN6ADDR_ANY_INIT
, length
, 0, *any
, 0, 0, 0};
146 struct odhcp6c_entry
*x
= odhcp6c_find_entry(STATE_RA_PREFIX
, &entry
);
147 if (x
&& IN6_ARE_ADDR_EQUAL(&x
->target
, any
)) {
148 odhcp6c_random(&x
->target
.s6_addr32
[2], 2 * sizeof(uint32_t));
149 } else if (odhcp6c_find_entry(STATE_IA_NA
, &entry
)) {
150 dhcpv6_request(DHCPV6_MSG_DECLINE
);
158 bool ra_rtnl_process(void)
161 uint32_t elapsed
= odhcp6c_elapsed();
164 ssize_t len
= recv(rtnl_sock
, buf
, sizeof(buf
), MSG_DONTWAIT
);
171 for (struct nlmsghdr
*nh
= (struct nlmsghdr
*)buf
; NLMSG_OK(nh
, (size_t)len
);
172 nh
= NLMSG_NEXT(nh
, len
)) {
173 struct ifaddrmsg
*ifa
= NLMSG_DATA(nh
);
174 struct in6_addr
*addr
= NULL
;
175 if (NLMSG_PAYLOAD(nh
, 0) < sizeof(*ifa
) || ifa
->ifa_index
!= if_index
||
176 (nh
->nlmsg_type
== RTM_NEWADDR
&& !(ifa
->ifa_flags
& IFA_F_DADFAILED
)) ||
177 (nh
->nlmsg_type
== RTM_DELADDR
&& !(ifa
->ifa_flags
& IFA_F_TENTATIVE
)) ||
178 (nh
->nlmsg_type
!= RTM_NEWADDR
&& nh
->nlmsg_type
!= RTM_DELADDR
))
181 ssize_t alen
= NLMSG_PAYLOAD(nh
, sizeof(*ifa
));
182 for (struct rtattr
*rta
= (struct rtattr
*)&ifa
[1]; RTA_OK(rta
, alen
);
183 rta
= RTA_NEXT(rta
, alen
))
184 if (rta
->rta_type
== IFA_ADDRESS
&& RTA_PAYLOAD(rta
) >= sizeof(*addr
))
185 addr
= RTA_DATA(rta
);
188 char ipbuf
[INET6_ADDRSTRLEN
];
189 inet_ntop(AF_INET6
, addr
, ipbuf
, sizeof(ipbuf
));
190 syslog(LOG_WARNING
, "duplicate address detected: %s (code: %u:%x)",
191 ipbuf
, (unsigned)nh
->nlmsg_type
, (unsigned)ifa
->ifa_flags
);
192 found
|= ra_deduplicate(addr
, ifa
->ifa_prefixlen
);
200 bool ra_process(void)
204 struct nd_router_advert
*adv
= (struct nd_router_advert
*)buf
;
205 struct odhcp6c_entry entry
= {IN6ADDR_ANY_INIT
, 0, 0, IN6ADDR_ANY_INIT
, 0, 0, 0};
206 const struct in6_addr any
= IN6ADDR_ANY_INIT
;
209 struct sockaddr_in6 from
;
210 socklen_t from_len
= sizeof(from
);
211 ssize_t len
= recvfrom(sock
, buf
, sizeof(buf
), MSG_DONTWAIT
, &from
, &from_len
);
214 else if (len
< (ssize_t
)sizeof(*adv
))
217 // Stop sending solicits
218 if (rs_attempt
> 0) {
227 uint32_t router_valid
= ntohs(adv
->nd_ra_router_lifetime
);
229 // Parse default route
232 entry
.router
= from
.sin6_addr
;
233 entry
.priority
= pref_to_priority(adv
->nd_ra_flags_reserved
);
234 if (entry
.priority
< 0)
235 entry
.priority
= pref_to_priority(0);
236 entry
.valid
= router_valid
;
237 entry
.preferred
= entry
.valid
;
238 odhcp6c_update_entry(STATE_RA_ROUTE
, &entry
);
240 // Parse ND parameters
241 if (ntohl(adv
->nd_ra_reachable
) <= 3600000)
242 update_proc("neigh", "base_reachable_time_ms", ntohl(adv
->nd_ra_reachable
));
244 if (ntohl(adv
->nd_ra_retransmit
) <= 60000)
245 update_proc("neigh", "retrans_time_ms", ntohl(adv
->nd_ra_retransmit
));
249 struct icmpv6_opt
*opt
;
250 icmpv6_for_each_option(opt
, &adv
[1], &buf
[len
]) {
251 if (opt
->type
== ND_OPT_MTU
) {
252 uint32_t *mtu
= (uint32_t*)&opt
->data
[2];
253 if (ntohl(*mtu
) >= 1280 && ntohl(*mtu
) <= 65535)
254 update_proc("conf", "mtu", ntohl(*mtu
));
255 } else if (opt
->type
== ND_OPT_ROUTE_INFORMATION
&& opt
->len
<= 3) {
256 entry
.router
= from
.sin6_addr
;
258 entry
.priority
= pref_to_priority(opt
->data
[1]);
259 entry
.length
= opt
->data
[0];
260 uint32_t *valid
= (uint32_t*)&opt
->data
[2];
261 entry
.valid
= ntohl(*valid
);
262 memcpy(&entry
.target
, &opt
->data
[6], (opt
->len
- 1) * 8);
264 if (entry
.length
> 128 || IN6_IS_ADDR_LINKLOCAL(&entry
.target
)
265 || IN6_IS_ADDR_LOOPBACK(&entry
.target
)
266 || IN6_IS_ADDR_MULTICAST(&entry
.target
))
269 if (entry
.priority
> 0)
270 odhcp6c_update_entry(STATE_RA_ROUTE
, &entry
);
271 } else if (opt
->type
== ND_OPT_PREFIX_INFORMATION
&& opt
->len
== 4) {
272 struct nd_opt_prefix_info
*pinfo
= (struct nd_opt_prefix_info
*)opt
;
274 entry
.target
= pinfo
->nd_opt_pi_prefix
;
275 entry
.priority
= 256;
276 entry
.length
= pinfo
->nd_opt_pi_prefix_len
;
277 entry
.valid
= ntohl(pinfo
->nd_opt_pi_valid_time
);
278 entry
.preferred
= ntohl(pinfo
->nd_opt_pi_preferred_time
);
280 if (entry
.length
> 128 || IN6_IS_ADDR_LINKLOCAL(&entry
.target
)
281 || IN6_IS_ADDR_LOOPBACK(&entry
.target
)
282 || IN6_IS_ADDR_MULTICAST(&entry
.target
)
283 || entry
.valid
< entry
.preferred
)
286 if (pinfo
->nd_opt_pi_flags_reserved
& ND_OPT_PI_FLAG_ONLINK
)
287 odhcp6c_update_entry_safe(STATE_RA_ROUTE
, &entry
, 7200);
289 if (!(pinfo
->nd_opt_pi_flags_reserved
& ND_OPT_PI_FLAG_AUTO
) ||
290 pinfo
->nd_opt_pi_prefix_len
!= 64)
293 entry
.target
.s6_addr32
[2] = lladdr
.s6_addr32
[2];
294 entry
.target
.s6_addr32
[3] = lladdr
.s6_addr32
[3];
296 odhcp6c_update_entry_safe(STATE_RA_PREFIX
, &entry
, 7200);
297 } else if (opt
->type
== ND_OPT_RECURSIVE_DNS
&& opt
->len
> 2) {
298 entry
.router
= from
.sin6_addr
;
301 uint32_t *valid
= (uint32_t*)&opt
->data
[2];
302 entry
.valid
= ntohl(*valid
);
305 for (ssize_t i
= 0; i
< (opt
->len
- 1) / 2; ++i
) {
306 memcpy(&entry
.target
, &opt
->data
[6 + i
* sizeof(entry
.target
)],
307 sizeof(entry
.target
));
308 odhcp6c_update_entry(STATE_RA_DNS
, &entry
);
314 struct odhcp6c_entry
*entry
= odhcp6c_get_state(STATE_RA_DNS
, &ra_dns_len
);
315 for (size_t i
= 0; i
< ra_dns_len
/ sizeof(*entry
); ++i
)
316 if (IN6_ARE_ADDR_EQUAL(&entry
[i
].router
, &from
.sin6_addr
) &&
317 entry
[i
].valid
> router_valid
)
318 entry
[i
].valid
= router_valid
;