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.
22 #include <arpa/inet.h>
23 #include <sys/socket.h>
24 #include <net/ethernet.h>
25 #include <netinet/ip6.h>
26 #include <netinet/icmp6.h>
27 #include <netpacket/packet.h>
29 #include <linux/rtnetlink.h>
30 #include <linux/filter.h>
37 static void handle_solicit(void *addr
, void *data
, size_t len
,
38 struct interface
*iface
, void *dest
);
39 static void handle_rtnetlink(void *addr
, void *data
, size_t len
,
40 struct interface
*iface
, void *dest
);
41 static void catch_rtnetlink(int error
);
43 static uint32_t rtnl_seqid
= 0;
44 static int ping_socket
= -1;
45 static struct odhcpd_event rtnl_event
= {{.fd
= -1}, handle_rtnetlink
, catch_rtnetlink
};
48 // Filter ICMPv6 messages of type neighbor soliciation
49 static struct sock_filter bpf
[] = {
50 BPF_STMT(BPF_LD
| BPF_B
| BPF_ABS
, offsetof(struct ip6_hdr
, ip6_nxt
)),
51 BPF_JUMP(BPF_JMP
| BPF_JEQ
| BPF_K
, IPPROTO_ICMPV6
, 0, 3),
52 BPF_STMT(BPF_LD
| BPF_B
| BPF_ABS
, sizeof(struct ip6_hdr
) +
53 offsetof(struct icmp6_hdr
, icmp6_type
)),
54 BPF_JUMP(BPF_JMP
| BPF_JEQ
| BPF_K
, ND_NEIGHBOR_SOLICIT
, 0, 1),
55 BPF_STMT(BPF_RET
| BPF_K
, 0xffffffff),
56 BPF_STMT(BPF_RET
| BPF_K
, 0),
58 static const struct sock_fprog bpf_prog
= {sizeof(bpf
) / sizeof(*bpf
), bpf
};
61 // Initialize NDP-proxy
66 // Setup netlink socket
67 if ((rtnl_event
.uloop
.fd
= odhcpd_open_rtnl()) < 0)
70 if (setsockopt(rtnl_event
.uloop
.fd
, SOL_SOCKET
, SO_RCVBUF
, &val
, sizeof(val
)))
71 setsockopt(rtnl_event
.uloop
.fd
, SOL_SOCKET
, SO_RCVBUFFORCE
, &val
, sizeof(val
));
73 // Receive netlink neighbor and ip-address events
74 uint32_t group
= RTNLGRP_IPV6_IFADDR
;
75 setsockopt(rtnl_event
.uloop
.fd
, SOL_NETLINK
,
76 NETLINK_ADD_MEMBERSHIP
, &group
, sizeof(group
));
77 group
= RTNLGRP_IPV6_ROUTE
;
78 setsockopt(rtnl_event
.uloop
.fd
, SOL_NETLINK
,
79 NETLINK_ADD_MEMBERSHIP
, &group
, sizeof(group
));
81 odhcpd_register(&rtnl_event
);
84 ping_socket
= socket(AF_INET6
, SOCK_RAW
| SOCK_CLOEXEC
, IPPROTO_ICMPV6
);
85 if (ping_socket
< 0) {
86 syslog(LOG_ERR
, "Unable to open raw socket: %s", strerror(errno
));
91 setsockopt(ping_socket
, IPPROTO_RAW
, IPV6_CHECKSUM
, &val
, sizeof(val
));
93 // This is required by RFC 4861
95 setsockopt(ping_socket
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
));
96 setsockopt(ping_socket
, IPPROTO_IPV6
, IPV6_UNICAST_HOPS
, &val
, sizeof(val
));
98 // Filter all packages, we only want to send
99 struct icmp6_filter filt
;
100 ICMP6_FILTER_SETBLOCKALL(&filt
);
101 setsockopt(ping_socket
, IPPROTO_ICMPV6
, ICMP6_FILTER
, &filt
, sizeof(filt
));
104 // Netlink socket, continued...
105 group
= RTNLGRP_NEIGH
;
106 setsockopt(rtnl_event
.uloop
.fd
, SOL_NETLINK
, NETLINK_ADD_MEMBERSHIP
, &group
, sizeof(group
));
112 static void dump_neigh_table(bool proxy
)
118 {sizeof(req
), RTM_GETNEIGH
, NLM_F_REQUEST
| NLM_F_DUMP
,
120 {.ndm_family
= AF_INET6
, .ndm_flags
= (proxy
) ? NTF_PROXY
: 0}
122 send(rtnl_event
.uloop
.fd
, &req
, sizeof(req
), MSG_DONTWAIT
);
123 odhcpd_process(&rtnl_event
);
127 int setup_ndp_interface(struct interface
*iface
, bool enable
)
130 snprintf(procbuf
, sizeof(procbuf
), "/proc/sys/net/ipv6/conf/%s/proxy_ndp", iface
->ifname
);
131 int procfd
= open(procbuf
, O_WRONLY
);
132 bool dump_neigh
= false;
134 if (iface
->ndp_event
.uloop
.fd
> 0) {
135 uloop_fd_delete(&iface
->ndp_event
.uloop
);
136 close(iface
->ndp_event
.uloop
.fd
);
137 iface
->ndp_event
.uloop
.fd
= -1;
139 if (!enable
|| iface
->ndp
!= RELAYD_RELAY
)
140 if (write(procfd
, "0\n", 2) < 0) {}
145 if (enable
&& (iface
->ra
== RELAYD_SERVER
||
146 iface
->dhcpv6
== RELAYD_SERVER
|| iface
->ndp
== RELAYD_RELAY
)) {
147 // Synthesize initial address events
150 struct ifaddrmsg ifa
;
152 {sizeof(req2
), RTM_GETADDR
, NLM_F_REQUEST
| NLM_F_DUMP
,
154 {.ifa_family
= AF_INET6
, .ifa_index
= iface
->ifindex
}
156 send(rtnl_event
.uloop
.fd
, &req2
, sizeof(req2
), MSG_DONTWAIT
);
159 if (enable
&& iface
->ndp
== RELAYD_RELAY
) {
160 if (write(procfd
, "1\n", 2) < 0) {}
163 int sock
= socket(AF_PACKET
, SOCK_DGRAM
| SOCK_CLOEXEC
, htons(ETH_P_IPV6
));
165 syslog(LOG_ERR
, "Unable to open packet socket: %s",
170 #ifdef PACKET_RECV_TYPE
171 int pktt
= 1 << PACKET_MULTICAST
;
172 setsockopt(sock
, SOL_PACKET
, PACKET_RECV_TYPE
, &pktt
, sizeof(pktt
));
175 if (setsockopt(sock
, SOL_SOCKET
, SO_ATTACH_FILTER
,
176 &bpf_prog
, sizeof(bpf_prog
))) {
177 syslog(LOG_ERR
, "Failed to set BPF: %s", strerror(errno
));
181 struct sockaddr_ll ll
= {
182 .sll_family
= AF_PACKET
,
183 .sll_ifindex
= iface
->ifindex
,
184 .sll_protocol
= htons(ETH_P_IPV6
),
190 bind(sock
, (struct sockaddr
*)&ll
, sizeof(ll
));
192 struct packet_mreq mreq
= {iface
->ifindex
, PACKET_MR_ALLMULTI
, ETH_ALEN
, {0}};
193 setsockopt(sock
, SOL_PACKET
, PACKET_ADD_MEMBERSHIP
, &mreq
, sizeof(mreq
));
195 iface
->ndp_event
.uloop
.fd
= sock
;
196 iface
->ndp_event
.handle_dgram
= handle_solicit
;
197 odhcpd_register(&iface
->ndp_event
);
199 // If we already were enabled dump is unnecessary, if not do dump
201 dump_neigh_table(false);
209 dump_neigh_table(true);
215 // Send an ICMP-ECHO. This is less for actually pinging but for the
216 // neighbor cache to be kept up-to-date.
217 static void ping6(struct in6_addr
*addr
,
218 const struct interface
*iface
)
220 struct sockaddr_in6 dest
= {AF_INET6
, 0, 0, *addr
, iface
->ifindex
};
221 struct icmp6_hdr echo
= {.icmp6_type
= ICMP6_ECHO_REQUEST
};
222 struct iovec iov
= {&echo
, sizeof(echo
)};
224 odhcpd_setup_route(addr
, 128, iface
, NULL
, 128, true);
225 odhcpd_send(ping_socket
, &dest
, &iov
, 1, iface
);
226 odhcpd_setup_route(addr
, 128, iface
, NULL
, 128, false);
230 // Handle solicitations
231 static void handle_solicit(void *addr
, void *data
, size_t len
,
232 struct interface
*iface
, _unused
void *dest
)
234 struct ip6_hdr
*ip6
= data
;
235 struct nd_neighbor_solicit
*req
= (struct nd_neighbor_solicit
*)&ip6
[1];
236 struct sockaddr_ll
*ll
= addr
;
238 // Solicitation is for duplicate address detection
239 bool ns_is_dad
= IN6_IS_ADDR_UNSPECIFIED(&ip6
->ip6_src
);
241 // Don't forward any non-DAD solicitation for external ifaces
242 // TODO: check if we should even forward DADs for them
243 if (iface
->external
&& !ns_is_dad
)
246 if (len
< sizeof(*ip6
) + sizeof(*req
))
247 return; // Invalid reqicitation
249 if (IN6_IS_ADDR_LINKLOCAL(&req
->nd_ns_target
) ||
250 IN6_IS_ADDR_LOOPBACK(&req
->nd_ns_target
) ||
251 IN6_IS_ADDR_MULTICAST(&req
->nd_ns_target
))
252 return; // Invalid target
254 char ipbuf
[INET6_ADDRSTRLEN
];
255 inet_ntop(AF_INET6
, &req
->nd_ns_target
, ipbuf
, sizeof(ipbuf
));
256 syslog(LOG_DEBUG
, "Got a NS for %s", ipbuf
);
259 odhcpd_get_mac(iface
, mac
);
260 if (!memcmp(ll
->sll_addr
, mac
, sizeof(mac
)))
261 return; // Looped back
264 list_for_each_entry(c
, &interfaces
, head
)
265 if (iface
->ndp
== RELAYD_RELAY
&& iface
!= c
&&
266 (ns_is_dad
|| !c
->external
))
267 ping6(&req
->nd_ns_target
, c
);
270 // Use rtnetlink to modify kernel routes
271 static void setup_route(struct in6_addr
*addr
, struct interface
*iface
, bool add
)
273 char namebuf
[INET6_ADDRSTRLEN
];
274 inet_ntop(AF_INET6
, addr
, namebuf
, sizeof(namebuf
));
275 syslog(LOG_NOTICE
, "%s about %s on %s",
276 (add
) ? "Learned" : "Forgot", namebuf
, iface
->ifname
);
278 if (iface
->learn_routes
)
279 odhcpd_setup_route(addr
, 128, iface
, NULL
, 1024, add
);
283 static int prefixcmp(const void *va
, const void *vb
)
285 const struct odhcpd_ipaddr
*a
= va
, *b
= vb
;
286 uint32_t a_pref
= ((a
->addr
.s6_addr
[0] & 0xfe) != 0xfc) ? a
->preferred
: 1;
287 uint32_t b_pref
= ((b
->addr
.s6_addr
[0] & 0xfe) != 0xfc) ? b
->preferred
: 1;
288 return (a_pref
< b_pref
) ? 1 : (a_pref
> b_pref
) ? -1 : 0;
291 // Check address update
292 static void check_updates(struct interface
*iface
)
294 struct odhcpd_ipaddr addr
[8] = {{IN6ADDR_ANY_INIT
, 0, 0, 0, 0}};
295 time_t now
= odhcpd_time();
296 ssize_t len
= odhcpd_get_interface_addresses(iface
->ifindex
, addr
, 8);
301 qsort(addr
, len
, sizeof(*addr
), prefixcmp
);
303 for (int i
= 0; i
< len
; ++i
) {
304 addr
[i
].addr
.s6_addr32
[3] = 0;
306 if (addr
[i
].preferred
< UINT32_MAX
- now
)
307 addr
[i
].preferred
+= now
;
309 if (addr
[i
].valid
< UINT32_MAX
- now
)
310 addr
[i
].valid
+= now
;
313 bool change
= len
!= (ssize_t
)iface
->ia_addr_len
;
314 for (ssize_t i
= 0; !change
&& i
< len
; ++i
)
315 if (!IN6_ARE_ADDR_EQUAL(&addr
[i
].addr
, &iface
->ia_addr
[i
].addr
) ||
316 (addr
[i
].preferred
> 0) != (iface
->ia_addr
[i
].preferred
> 0) ||
317 addr
[i
].valid
< iface
->ia_addr
[i
].valid
||
318 addr
[i
].preferred
< iface
->ia_addr
[i
].preferred
)
322 dhcpv6_ia_preupdate(iface
);
324 memcpy(iface
->ia_addr
, addr
, len
* sizeof(*addr
));
325 iface
->ia_addr_len
= len
;
328 dhcpv6_ia_postupdate(iface
, now
);
335 // Handler for neighbor cache entries from the kernel. This is our source
336 // to learn and unlearn hosts on interfaces.
337 static void handle_rtnetlink(_unused
void *addr
, void *data
, size_t len
,
338 _unused
struct interface
*iface
, _unused
void *dest
)
340 bool dump_neigh
= false;
341 struct in6_addr last_solicited
= IN6ADDR_ANY_INIT
;
343 for (struct nlmsghdr
*nh
= data
; NLMSG_OK(nh
, len
);
344 nh
= NLMSG_NEXT(nh
, len
)) {
345 struct ndmsg
*ndm
= NLMSG_DATA(nh
);
346 struct rtmsg
*rtm
= NLMSG_DATA(nh
);
348 bool is_addr
= (nh
->nlmsg_type
== RTM_NEWADDR
349 || nh
->nlmsg_type
== RTM_DELADDR
);
350 bool is_route
= (nh
->nlmsg_type
== RTM_NEWROUTE
351 || nh
->nlmsg_type
== RTM_DELROUTE
);
352 bool is_neigh
= (nh
->nlmsg_type
== RTM_NEWNEIGH
353 || nh
->nlmsg_type
== RTM_DELNEIGH
);
355 // Family and ifindex are on the same offset for NEIGH and ADDR
356 if ((!is_addr
&& !is_route
&& !is_neigh
)
357 || NLMSG_PAYLOAD(nh
, 0) < sizeof(*ndm
)
358 || ndm
->ndm_family
!= AF_INET6
)
361 // Inform about a change in default route
362 if (is_route
&& rtm
->rtm_dst_len
== 0)
368 size_t rta_offset
= (is_addr
) ? sizeof(struct ifaddrmsg
) : sizeof(*ndm
);
369 uint16_t atype
= (is_addr
) ? IFA_ADDRESS
: NDA_DST
;
370 ssize_t alen
= NLMSG_PAYLOAD(nh
, rta_offset
);
371 struct in6_addr
*addr
= NULL
;
373 for (struct rtattr
*rta
= (void*)(((uint8_t*)ndm
) + rta_offset
);
374 RTA_OK(rta
, alen
); rta
= RTA_NEXT(rta
, alen
)) {
375 if (rta
->rta_type
== atype
&&
376 RTA_PAYLOAD(rta
) >= sizeof(*addr
)) {
377 addr
= RTA_DATA(rta
);
382 struct interface
*iface
= odhcpd_get_interface_by_index(ndm
->ndm_ifindex
);
386 // Address not specified or unrelated
387 if (!addr
|| IN6_IS_ADDR_LINKLOCAL(addr
) ||
388 IN6_IS_ADDR_MULTICAST(addr
))
394 add
= (nh
->nlmsg_type
== RTM_NEWADDR
);
396 add
= (nh
->nlmsg_type
== RTM_NEWNEIGH
&& (ndm
->ndm_state
&
397 (NUD_REACHABLE
| NUD_STALE
| NUD_DELAY
| NUD_PROBE
398 | NUD_PERMANENT
| NUD_NOARP
)));
400 if (iface
->ndp
== RELAYD_RELAY
) {
401 // Replay change to all neighbor cache
405 struct nlattr nla_dst
;
408 {sizeof(req
), RTM_DELNEIGH
, NLM_F_REQUEST
,
410 {.ndm_family
= AF_INET6
, .ndm_flags
= NTF_PROXY
},
411 {sizeof(struct nlattr
) + sizeof(struct in6_addr
), NDA_DST
},
415 if (ndm
->ndm_flags
& NTF_PROXY
) {
416 // Dump & flush proxy entries
417 if (nh
->nlmsg_type
== RTM_NEWNEIGH
) {
418 req
.ndm
.ndm_ifindex
= iface
->ifindex
;
419 send(rtnl_event
.uloop
.fd
, &req
, sizeof(req
), MSG_DONTWAIT
);
420 setup_route(addr
, iface
, false);
425 list_for_each_entry(c
, &interfaces
, head
) {
429 if (c
->ndp
== RELAYD_RELAY
) {
430 req
.nh
.nlmsg_type
= RTM_NEWNEIGH
;
431 req
.nh
.nlmsg_flags
|= NLM_F_CREATE
| NLM_F_REPLACE
;
433 req
.ndm
.ndm_ifindex
= c
->ifindex
;
434 send(rtnl_event
.uloop
.fd
, &req
, sizeof(req
), MSG_DONTWAIT
);
435 } else { // Delete NDP cache from interfaces without relay
436 req
.nh
.nlmsg_type
= RTM_DELNEIGH
;
437 req
.nh
.nlmsg_flags
&= ~(NLM_F_CREATE
| NLM_F_REPLACE
);
439 req
.ndm
.ndm_ifindex
= c
->ifindex
;
440 send(rtnl_event
.uloop
.fd
, &req
, sizeof(req
), MSG_DONTWAIT
);
444 setup_route(addr
, iface
, true);
446 if (nh
->nlmsg_type
== RTM_NEWNEIGH
) {
447 // might be locally originating
448 if (!IN6_ARE_ADDR_EQUAL(&last_solicited
, addr
)) {
449 last_solicited
= *addr
;
452 list_for_each_entry(c
, &interfaces
, head
)
453 if (iface
->ndp
== RELAYD_RELAY
&& iface
!= c
&&
454 !c
->external
== false)
459 list_for_each_entry(c
, &interfaces
, head
) {
460 if (c
->ndp
== RELAYD_RELAY
&& iface
!= c
) {
461 req
.ndm
.ndm_ifindex
= c
->ifindex
;
462 send(rtnl_event
.uloop
.fd
, &req
, sizeof(req
), MSG_DONTWAIT
);
465 setup_route(addr
, iface
, false);
467 // also: dump to add proxies back in case it moved elsewhere
474 check_updates(iface
);
476 if (iface
->dhcpv6
== RELAYD_SERVER
)
477 iface
->ia_reconf
= true;
479 if (iface
->ndp
== RELAYD_RELAY
&& iface
->master
) {
480 // Replay address changes on all slave interfaces
481 nh
->nlmsg_flags
= NLM_F_REQUEST
;
483 if (nh
->nlmsg_type
== RTM_NEWADDR
)
484 nh
->nlmsg_flags
|= NLM_F_CREATE
| NLM_F_REPLACE
;
487 list_for_each_entry(c
, &interfaces
, head
) {
488 if (c
->ndp
== RELAYD_RELAY
&& !c
->master
) {
489 ndm
->ndm_ifindex
= c
->ifindex
;
490 send(rtnl_event
.uloop
.fd
, nh
, nh
->nlmsg_len
, MSG_DONTWAIT
);
498 dump_neigh_table(false);
501 static void catch_rtnetlink(int error
)
503 if (error
== ENOBUFS
) {
506 struct ifaddrmsg ifa
;
508 {sizeof(req2
), RTM_GETADDR
, NLM_F_REQUEST
| NLM_F_DUMP
,
510 {.ifa_family
= AF_INET6
}
512 send(rtnl_event
.uloop
.fd
, &req2
, sizeof(req2
), MSG_DONTWAIT
);