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.
24 #include <sys/socket.h>
25 #include <netinet/in.h>
26 #include <netinet/icmp6.h>
28 #include <linux/rtnetlink.h>
35 static int sock
= -1, rtnl_sock
= -1;
36 static unsigned if_index
= 0;
37 static char if_name
[IF_NAMESIZE
] = {0};
38 static volatile int rs_attempt
= 0;
39 static struct in6_addr lladdr
= IN6ADDR_ANY_INIT
;
41 static void ra_send_rs(int signal
__attribute__((unused
)));
43 int ra_init(const char *ifname
)
45 sock
= socket(AF_INET6
, SOCK_RAW
| SOCK_CLOEXEC
, IPPROTO_ICMPV6
);
46 if_index
= if_nametoindex(ifname
);
47 strncpy(if_name
, ifname
, sizeof(if_name
) - 1);
49 // Filter ICMPv6 package types
50 struct icmp6_filter filt
;
51 ICMP6_FILTER_SETBLOCKALL(&filt
);
52 ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT
, &filt
);
53 setsockopt(sock
, IPPROTO_ICMPV6
, ICMP6_FILTER
, &filt
, sizeof(filt
));
56 struct ipv6_mreq an
= {ALL_IPV6_NODES
, if_index
};
57 setsockopt(sock
, IPPROTO_IPV6
, IPV6_ADD_MEMBERSHIP
, &an
, sizeof(an
));
59 // Let the kernel compute our checksums
61 setsockopt(sock
, IPPROTO_RAW
, IPV6_CHECKSUM
, &val
, sizeof(val
));
63 // This is required by RFC 4861
65 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
));
68 setsockopt(sock
, SOL_SOCKET
, SO_BINDTODEVICE
, ifname
, strlen(ifname
));
71 const pid_t ourpid
= getpid();
72 fcntl(sock
, F_SETOWN
, ourpid
);
73 fcntl(sock
, F_SETFL
, fcntl(sock
, F_GETFL
) | O_ASYNC
);
76 FILE *fp
= fopen("/proc/net/if_inet6", "r");
78 char addrbuf
[33], ifbuf
[16];
79 while (fscanf(fp
, "%32s %*x %*x %*x %*x %15s", addrbuf
, ifbuf
) == 2) {
80 if (!strcmp(ifbuf
, if_name
)) {
81 script_unhexlify((uint8_t*)&lladdr
, sizeof(lladdr
), addrbuf
);
88 // Open rtnetlink socket
89 rtnl_sock
= socket(AF_NETLINK
, SOCK_RAW
| SOCK_CLOEXEC
, NETLINK_ROUTE
);
90 struct sockaddr_nl rtnl_kernel
= { .nl_family
= AF_NETLINK
};
91 if (connect(rtnl_sock
, (struct sockaddr
*)&rtnl_kernel
, sizeof(rtnl_kernel
)))
93 uint32_t group
= RTNLGRP_IPV6_IFADDR
;
94 setsockopt(rtnl_sock
, SOL_NETLINK
, NETLINK_ADD_MEMBERSHIP
, &group
, sizeof(group
));
97 fcntl(rtnl_sock
, F_SETOWN
, ourpid
);
98 fcntl(rtnl_sock
, F_SETFL
, fcntl(rtnl_sock
, F_GETFL
) | O_ASYNC
);
101 signal(SIGALRM
, ra_send_rs
);
108 static void ra_send_rs(int signal
__attribute__((unused
)))
110 const struct icmp6_hdr rs
= {ND_ROUTER_SOLICIT
, 0, 0, {{0}}};
111 const struct sockaddr_in6 dest
= {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, if_index
};
112 sendto(sock
, &rs
, sizeof(rs
), MSG_DONTWAIT
, (struct sockaddr
*)&dest
, sizeof(dest
));
114 if (++rs_attempt
<= 3)
119 static int16_t pref_to_priority(uint8_t flags
)
121 flags
= (flags
>> 3) & 0x03;
122 return (flags
== 0x0) ? 1024 : (flags
== 0x1) ? 512 :
123 (flags
== 0x3) ? 2048 : -1;
127 static void update_proc(const char *sect
, const char *opt
, uint32_t value
)
130 snprintf(buf
, sizeof(buf
), "/proc/sys/net/ipv6/%s/%s/%s", sect
, if_name
, opt
);
132 int fd
= open(buf
, O_WRONLY
);
133 write(fd
, buf
, snprintf(buf
, sizeof(buf
), "%u", value
));
138 static bool ra_deduplicate(const struct in6_addr
*any
, uint8_t length
)
140 struct odhcp6c_entry entry
= {IN6ADDR_ANY_INIT
, length
, 0, *any
, 0, 0};
141 struct odhcp6c_entry
*x
= odhcp6c_find_entry(STATE_RA_PREFIX
, &entry
);
142 if (x
&& IN6_ARE_ADDR_EQUAL(&x
->target
, any
)) {
143 odhcp6c_random(&x
->target
.s6_addr32
[2], 2 * sizeof(uint32_t));
144 } else if (odhcp6c_find_entry(STATE_IA_NA
, &entry
)) {
145 dhcpv6_request(DHCPV6_MSG_DECLINE
);
153 bool ra_rtnl_process(void)
158 ssize_t len
= recv(rtnl_sock
, buf
, sizeof(buf
), MSG_DONTWAIT
);
162 for (struct nlmsghdr
*nh
= (struct nlmsghdr
*)buf
; NLMSG_OK(nh
, (size_t)len
);
163 nh
= NLMSG_NEXT(nh
, len
)) {
164 struct ifaddrmsg
*ifa
= NLMSG_DATA(nh
);
165 struct in6_addr
*addr
= NULL
;
166 if (NLMSG_PAYLOAD(nh
, 0) < sizeof(*ifa
) || ifa
->ifa_index
!= if_index
||
167 (nh
->nlmsg_type
== RTM_NEWADDR
&& !(ifa
->ifa_flags
& IFA_F_DADFAILED
)) ||
168 (nh
->nlmsg_type
== RTM_DELADDR
&& !(ifa
->ifa_flags
& IFA_F_TENTATIVE
)))
171 ssize_t alen
= NLMSG_PAYLOAD(nh
, sizeof(*ifa
));
172 for (struct rtattr
*rta
= (struct rtattr
*)&ifa
[1]; RTA_OK(rta
, alen
);
173 rta
= RTA_NEXT(rta
, alen
))
174 if (rta
->rta_type
== IFA_ADDRESS
&& RTA_PAYLOAD(rta
) >= sizeof(*addr
))
175 addr
= RTA_DATA(rta
);
178 found
|= ra_deduplicate(addr
, ifa
->ifa_prefixlen
);
185 bool ra_process(void)
189 struct nd_router_advert
*adv
= (struct nd_router_advert
*)buf
;
190 struct odhcp6c_entry entry
= {IN6ADDR_ANY_INIT
, 0, 0, IN6ADDR_ANY_INIT
, 0, 0};
191 const struct in6_addr any
= IN6ADDR_ANY_INIT
;
195 struct sockaddr_in6 from
;
196 socklen_t from_len
= sizeof(from
);
197 ssize_t len
= recvfrom(sock
, buf
, sizeof(buf
), MSG_DONTWAIT
, &from
, &from_len
);
200 else if (len
< (ssize_t
)sizeof(*adv
))
203 // Stop sending solicits
204 if (rs_attempt
> 0) {
210 uint32_t router_valid
= ntohs(adv
->nd_ra_router_lifetime
);
212 // Parse default route
213 entry
.router
= from
.sin6_addr
;
214 entry
.priority
= pref_to_priority(adv
->nd_ra_flags_reserved
);
215 if (entry
.priority
< 0)
216 entry
.priority
= pref_to_priority(0);
217 entry
.valid
= router_valid
;
218 entry
.preferred
= entry
.valid
;
219 odhcp6c_update_entry(STATE_RA_ROUTE
, &entry
);
221 // Parse ND parameters
222 if (adv
->nd_ra_reachable
)
223 update_proc("neigh", "base_reachable_time_ms", ntohl(adv
->nd_ra_reachable
));
225 if (adv
->nd_ra_retransmit
)
226 update_proc("neigh", "retrans_time_ms", ntohl(adv
->nd_ra_retransmit
));
230 struct icmpv6_opt
*opt
;
231 icmpv6_for_each_option(opt
, &adv
[1], &buf
[len
]) {
232 if (opt
->type
== ND_OPT_MTU
) {
233 update_proc("conf", "mtu", ntohl(*((uint32_t*)&opt
->data
[2])));
234 } else if (opt
->type
== ND_OPT_ROUTE_INFORMATION
&& opt
->len
<= 3) {
235 entry
.router
= from
.sin6_addr
;
237 entry
.priority
= pref_to_priority(opt
->data
[1]);
238 entry
.length
= opt
->data
[0];
239 entry
.valid
= ntohl(*((uint32_t*)&opt
->data
[2]));
240 memcpy(&entry
.target
, &opt
->data
[6], (opt
->len
- 1) * 8);
242 if (entry
.length
> 128 || IN6_IS_ADDR_LINKLOCAL(&entry
.target
)
243 || IN6_IS_ADDR_LOOPBACK(&entry
.target
)
244 || IN6_IS_ADDR_MULTICAST(&entry
.target
))
247 if (entry
.priority
> 0)
248 odhcp6c_update_entry(STATE_RA_ROUTE
, &entry
);
249 } else if (opt
->type
== ND_OPT_PREFIX_INFORMATION
&& opt
->len
== 4) {
250 struct nd_opt_prefix_info
*pinfo
= (struct nd_opt_prefix_info
*)opt
;
252 entry
.target
= pinfo
->nd_opt_pi_prefix
;
253 entry
.priority
= 256;
254 entry
.length
= pinfo
->nd_opt_pi_prefix_len
;
255 entry
.valid
= ntohl(pinfo
->nd_opt_pi_valid_time
);
256 entry
.preferred
= ntohl(pinfo
->nd_opt_pi_preferred_time
);
258 if (entry
.length
> 128 || IN6_IS_ADDR_LINKLOCAL(&entry
.target
)
259 || IN6_IS_ADDR_LOOPBACK(&entry
.target
)
260 || IN6_IS_ADDR_MULTICAST(&entry
.target
)
261 || entry
.valid
< entry
.preferred
)
264 if (pinfo
->nd_opt_pi_flags_reserved
& ND_OPT_PI_FLAG_ONLINK
)
265 odhcp6c_update_entry_safe(STATE_RA_ROUTE
, &entry
, 7200);
267 if (!(pinfo
->nd_opt_pi_flags_reserved
& ND_OPT_PI_FLAG_AUTO
) ||
268 pinfo
->nd_opt_pi_prefix_len
!= 64)
271 entry
.target
.s6_addr32
[2] = lladdr
.s6_addr32
[2];
272 entry
.target
.s6_addr32
[3] = lladdr
.s6_addr32
[3];
274 odhcp6c_update_entry_safe(STATE_RA_PREFIX
, &entry
, 7200);
275 } else if (opt
->type
== ND_OPT_RECURSIVE_DNS
&& opt
->len
> 2) {
276 entry
.router
= from
.sin6_addr
;
279 entry
.valid
= ntohl(*((uint32_t*)&opt
->data
[2]));
282 for (ssize_t i
= 0; i
< (opt
->len
- 1) / 2; ++i
) {
283 memcpy(&entry
.target
, &opt
->data
[6 + i
* sizeof(entry
.target
)],
284 sizeof(entry
.target
));
285 odhcp6c_update_entry(STATE_RA_DNS
, &entry
);
291 struct odhcp6c_entry
*entry
= odhcp6c_get_state(STATE_RA_DNS
, &ra_dns_len
);
292 for (size_t i
= 0; i
< ra_dns_len
/ sizeof(*entry
); ++i
)
293 if (IN6_ARE_ADDR_EQUAL(&entry
[i
].router
, &from
.sin6_addr
) &&
294 entry
[i
].valid
> router_valid
)
295 entry
[i
].valid
= router_valid
;