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>
36 static void handle_solicit(void *addr
, void *data
, size_t len
,
37 struct interface
*iface
, void *dest
);
38 static void handle_rtnetlink(void *addr
, void *data
, size_t len
,
39 struct interface
*iface
, void *dest
);
41 static uint32_t rtnl_seqid
= 0;
42 static int ping_socket
= -1;
43 static struct odhcpd_event rtnl_event
= {{.fd
= -1}, handle_rtnetlink
};
46 // Filter ICMPv6 messages of type neighbor soliciation
47 static struct sock_filter bpf
[] = {
48 BPF_STMT(BPF_LD
| BPF_B
| BPF_ABS
, offsetof(struct ip6_hdr
, ip6_nxt
)),
49 BPF_JUMP(BPF_JMP
| BPF_JEQ
| BPF_K
, IPPROTO_ICMPV6
, 0, 3),
50 BPF_STMT(BPF_LD
| BPF_B
| BPF_ABS
, sizeof(struct ip6_hdr
) +
51 offsetof(struct icmp6_hdr
, icmp6_type
)),
52 BPF_JUMP(BPF_JMP
| BPF_JEQ
| BPF_K
, ND_NEIGHBOR_SOLICIT
, 0, 1),
53 BPF_STMT(BPF_RET
| BPF_K
, 0xffffffff),
54 BPF_STMT(BPF_RET
| BPF_K
, 0),
56 static const struct sock_fprog bpf_prog
= {sizeof(bpf
) / sizeof(*bpf
), bpf
};
59 // Initialize NDP-proxy
62 // Setup netlink socket
63 if ((rtnl_event
.uloop
.fd
= odhcpd_open_rtnl()) < 0)
66 // Receive netlink neighbor and ip-address events
67 uint32_t group
= RTNLGRP_IPV6_IFADDR
;
68 setsockopt(rtnl_event
.uloop
.fd
, SOL_NETLINK
,
69 NETLINK_ADD_MEMBERSHIP
, &group
, sizeof(group
));
70 group
= RTNLGRP_IPV6_ROUTE
;
71 setsockopt(rtnl_event
.uloop
.fd
, SOL_NETLINK
,
72 NETLINK_ADD_MEMBERSHIP
, &group
, sizeof(group
));
74 odhcpd_register(&rtnl_event
);
77 ping_socket
= socket(AF_INET6
, SOCK_RAW
| SOCK_CLOEXEC
, IPPROTO_ICMPV6
);
78 if (ping_socket
< 0) {
79 syslog(LOG_ERR
, "Unable to open raw socket: %s", strerror(errno
));
84 setsockopt(ping_socket
, IPPROTO_RAW
, IPV6_CHECKSUM
, &val
, sizeof(val
));
86 // This is required by RFC 4861
88 setsockopt(ping_socket
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
));
89 setsockopt(ping_socket
, IPPROTO_IPV6
, IPV6_UNICAST_HOPS
, &val
, sizeof(val
));
91 // Filter all packages, we only want to send
92 struct icmp6_filter filt
;
93 ICMP6_FILTER_SETBLOCKALL(&filt
);
94 setsockopt(ping_socket
, IPPROTO_ICMPV6
, ICMP6_FILTER
, &filt
, sizeof(filt
));
97 // Netlink socket, continued...
98 group
= RTNLGRP_NEIGH
;
99 setsockopt(rtnl_event
.uloop
.fd
, SOL_NETLINK
, NETLINK_ADD_MEMBERSHIP
, &group
, sizeof(group
));
105 static void dump_neigh_table(bool proxy
)
111 {sizeof(req
), RTM_GETNEIGH
, NLM_F_REQUEST
| NLM_F_DUMP
,
113 {.ndm_family
= AF_INET6
, .ndm_flags
= (proxy
) ? NTF_PROXY
: 0}
115 send(rtnl_event
.uloop
.fd
, &req
, sizeof(req
), MSG_DONTWAIT
);
116 odhcpd_process(&rtnl_event
);
120 int setup_ndp_interface(struct interface
*iface
, bool enable
)
123 snprintf(procbuf
, sizeof(procbuf
), "/proc/sys/net/ipv6/conf/%s/proxy_ndp", iface
->ifname
);
124 int procfd
= open(procbuf
, O_WRONLY
);
125 bool dump_neigh
= false;
127 if (iface
->ndp_event
.uloop
.fd
> 0) {
128 uloop_fd_delete(&iface
->ndp_event
.uloop
);
129 close(iface
->ndp_event
.uloop
.fd
);
130 iface
->ndp_event
.uloop
.fd
= -1;
132 if (!enable
|| iface
->ndp
!= RELAYD_RELAY
)
133 if (write(procfd
, "0\n", 2) < 0) {}
138 if (enable
&& (iface
->ra
== RELAYD_SERVER
||
139 iface
->dhcpv6
== RELAYD_SERVER
|| iface
->ndp
== RELAYD_RELAY
)) {
140 // Synthesize initial address events
143 struct ifaddrmsg ifa
;
145 {sizeof(req2
), RTM_GETADDR
, NLM_F_REQUEST
| NLM_F_DUMP
,
147 {.ifa_family
= AF_INET6
, .ifa_index
= iface
->ifindex
}
149 send(rtnl_event
.uloop
.fd
, &req2
, sizeof(req2
), MSG_DONTWAIT
);
152 if (enable
&& iface
->ndp
== RELAYD_RELAY
) {
153 if (write(procfd
, "1\n", 2) < 0) {}
156 int sock
= socket(AF_PACKET
, SOCK_DGRAM
| SOCK_CLOEXEC
, htons(ETH_P_IPV6
));
158 syslog(LOG_ERR
, "Unable to open packet socket: %s",
163 #ifdef PACKET_RECV_TYPE
164 int pktt
= 1 << PACKET_MULTICAST
;
165 setsockopt(sock
, SOL_PACKET
, PACKET_RECV_TYPE
, &pktt
, sizeof(pktt
));
168 if (setsockopt(sock
, SOL_SOCKET
, SO_ATTACH_FILTER
,
169 &bpf_prog
, sizeof(bpf_prog
))) {
170 syslog(LOG_ERR
, "Failed to set BPF: %s", strerror(errno
));
174 struct sockaddr_ll ll
= {
175 .sll_family
= AF_PACKET
,
176 .sll_ifindex
= iface
->ifindex
,
177 .sll_protocol
= htons(ETH_P_IPV6
),
183 bind(sock
, (struct sockaddr
*)&ll
, sizeof(ll
));
185 struct packet_mreq mreq
= {iface
->ifindex
, PACKET_MR_ALLMULTI
, ETH_ALEN
, {0}};
186 setsockopt(sock
, SOL_PACKET
, PACKET_ADD_MEMBERSHIP
, &mreq
, sizeof(mreq
));
188 iface
->ndp_event
.uloop
.fd
= sock
;
189 iface
->ndp_event
.handle_dgram
= handle_solicit
;
190 odhcpd_register(&iface
->ndp_event
);
192 // If we already were enabled dump is unnecessary, if not do dump
194 dump_neigh_table(false);
202 dump_neigh_table(true);
208 // Send an ICMP-ECHO. This is less for actually pinging but for the
209 // neighbor cache to be kept up-to-date.
210 static void ping6(struct in6_addr
*addr
,
211 const struct interface
*iface
)
213 struct sockaddr_in6 dest
= {AF_INET6
, 0, 0, *addr
, iface
->ifindex
};
214 struct icmp6_hdr echo
= {.icmp6_type
= ICMP6_ECHO_REQUEST
};
215 struct iovec iov
= {&echo
, sizeof(echo
)};
217 odhcpd_setup_route(addr
, 128, iface
, NULL
, 128, true);
218 odhcpd_send(ping_socket
, &dest
, &iov
, 1, iface
);
219 odhcpd_setup_route(addr
, 128, iface
, NULL
, 128, false);
223 // Handle solicitations
224 static void handle_solicit(void *addr
, void *data
, size_t len
,
225 struct interface
*iface
, _unused
void *dest
)
227 struct ip6_hdr
*ip6
= data
;
228 struct nd_neighbor_solicit
*req
= (struct nd_neighbor_solicit
*)&ip6
[1];
229 struct sockaddr_ll
*ll
= addr
;
231 // Solicitation is for duplicate address detection
232 bool ns_is_dad
= IN6_IS_ADDR_UNSPECIFIED(&ip6
->ip6_src
);
234 // Don't forward any non-DAD solicitation for external ifaces
235 // TODO: check if we should even forward DADs for them
236 if (iface
->external
&& !ns_is_dad
)
239 if (len
< sizeof(*ip6
) + sizeof(*req
))
240 return; // Invalid reqicitation
242 if (IN6_IS_ADDR_LINKLOCAL(&req
->nd_ns_target
) ||
243 IN6_IS_ADDR_LOOPBACK(&req
->nd_ns_target
) ||
244 IN6_IS_ADDR_MULTICAST(&req
->nd_ns_target
))
245 return; // Invalid target
247 char ipbuf
[INET6_ADDRSTRLEN
];
248 inet_ntop(AF_INET6
, &req
->nd_ns_target
, ipbuf
, sizeof(ipbuf
));
249 syslog(LOG_DEBUG
, "Got a NS for %s", ipbuf
);
252 odhcpd_get_mac(iface
, mac
);
253 if (!memcmp(ll
->sll_addr
, mac
, sizeof(mac
)))
254 return; // Looped back
257 list_for_each_entry(c
, &interfaces
, head
)
258 if (iface
->ndp
== RELAYD_RELAY
&& iface
!= c
&&
259 (ns_is_dad
|| !c
->external
))
260 ping6(&req
->nd_ns_target
, c
);
263 // Use rtnetlink to modify kernel routes
264 static void setup_route(struct in6_addr
*addr
, struct interface
*iface
, bool add
)
266 char namebuf
[INET6_ADDRSTRLEN
];
267 inet_ntop(AF_INET6
, addr
, namebuf
, sizeof(namebuf
));
268 syslog(LOG_NOTICE
, "%s about %s on %s",
269 (add
) ? "Learned" : "Forgot", namebuf
, iface
->ifname
);
271 if (iface
->learn_routes
)
272 odhcpd_setup_route(addr
, 128, iface
, NULL
, 1024, add
);
276 // Handler for neighbor cache entries from the kernel. This is our source
277 // to learn and unlearn hosts on interfaces.
278 static void handle_rtnetlink(_unused
void *addr
, void *data
, size_t len
,
279 _unused
struct interface
*iface
, _unused
void *dest
)
281 bool dump_neigh
= false;
282 struct in6_addr last_solicited
= IN6ADDR_ANY_INIT
;
284 for (struct nlmsghdr
*nh
= data
; NLMSG_OK(nh
, len
);
285 nh
= NLMSG_NEXT(nh
, len
)) {
286 struct ndmsg
*ndm
= NLMSG_DATA(nh
);
287 struct rtmsg
*rtm
= NLMSG_DATA(nh
);
289 bool is_addr
= (nh
->nlmsg_type
== RTM_NEWADDR
290 || nh
->nlmsg_type
== RTM_DELADDR
);
291 bool is_route
= (nh
->nlmsg_type
== RTM_NEWROUTE
292 || nh
->nlmsg_type
== RTM_DELROUTE
);
293 bool is_neigh
= (nh
->nlmsg_type
== RTM_NEWNEIGH
294 || nh
->nlmsg_type
== RTM_DELNEIGH
);
296 // Family and ifindex are on the same offset for NEIGH and ADDR
297 if ((!is_addr
&& !is_route
&& !is_neigh
)
298 || NLMSG_PAYLOAD(nh
, 0) < sizeof(*ndm
)
299 || ndm
->ndm_family
!= AF_INET6
)
302 // Inform about a change in default route
303 if (is_route
&& rtm
->rtm_dst_len
== 0)
309 size_t rta_offset
= (is_addr
) ? sizeof(struct ifaddrmsg
) : sizeof(*ndm
);
310 uint16_t atype
= (is_addr
) ? IFA_ADDRESS
: NDA_DST
;
311 ssize_t alen
= NLMSG_PAYLOAD(nh
, rta_offset
);
312 struct in6_addr
*addr
= NULL
;
314 for (struct rtattr
*rta
= (void*)(((uint8_t*)ndm
) + rta_offset
);
315 RTA_OK(rta
, alen
); rta
= RTA_NEXT(rta
, alen
)) {
316 if (rta
->rta_type
== atype
&&
317 RTA_PAYLOAD(rta
) >= sizeof(*addr
)) {
318 addr
= RTA_DATA(rta
);
323 struct interface
*iface
= odhcpd_get_interface_by_index(ndm
->ndm_ifindex
);
327 // Address not specified or unrelated
328 if (!addr
|| IN6_IS_ADDR_LINKLOCAL(addr
) ||
329 IN6_IS_ADDR_MULTICAST(addr
))
335 add
= (nh
->nlmsg_type
== RTM_NEWADDR
);
337 add
= (nh
->nlmsg_type
== RTM_NEWNEIGH
&& (ndm
->ndm_state
&
338 (NUD_REACHABLE
| NUD_STALE
| NUD_DELAY
| NUD_PROBE
339 | NUD_PERMANENT
| NUD_NOARP
)));
341 if (iface
->ndp
== RELAYD_RELAY
) {
342 // Replay change to all neighbor cache
346 struct nlattr nla_dst
;
349 {sizeof(req
), RTM_DELNEIGH
, NLM_F_REQUEST
,
351 {.ndm_family
= AF_INET6
, .ndm_flags
= NTF_PROXY
},
352 {sizeof(struct nlattr
) + sizeof(struct in6_addr
), NDA_DST
},
356 if (ndm
->ndm_flags
& NTF_PROXY
) {
357 // Dump & flush proxy entries
358 if (nh
->nlmsg_type
== RTM_NEWNEIGH
) {
359 req
.ndm
.ndm_ifindex
= iface
->ifindex
;
360 send(rtnl_event
.uloop
.fd
, &req
, sizeof(req
), MSG_DONTWAIT
);
361 setup_route(addr
, iface
, false);
366 list_for_each_entry(c
, &interfaces
, head
) {
370 if (c
->ndp
== RELAYD_RELAY
) {
371 req
.nh
.nlmsg_type
= RTM_NEWNEIGH
;
372 req
.nh
.nlmsg_flags
|= NLM_F_CREATE
| NLM_F_REPLACE
;
374 req
.ndm
.ndm_ifindex
= c
->ifindex
;
375 send(rtnl_event
.uloop
.fd
, &req
, sizeof(req
), MSG_DONTWAIT
);
376 } else { // Delete NDP cache from interfaces without relay
377 req
.nh
.nlmsg_type
= RTM_DELNEIGH
;
378 req
.nh
.nlmsg_flags
&= ~(NLM_F_CREATE
| NLM_F_REPLACE
);
380 req
.ndm
.ndm_ifindex
= c
->ifindex
;
381 send(rtnl_event
.uloop
.fd
, &req
, sizeof(req
), MSG_DONTWAIT
);
385 setup_route(addr
, iface
, true);
387 if (nh
->nlmsg_type
== RTM_NEWNEIGH
) {
388 // might be locally originating
389 if (!IN6_ARE_ADDR_EQUAL(&last_solicited
, addr
)) {
390 last_solicited
= *addr
;
393 list_for_each_entry(c
, &interfaces
, head
)
394 if (iface
->ndp
== RELAYD_RELAY
&& iface
!= c
&&
395 !c
->external
== false)
400 list_for_each_entry(c
, &interfaces
, head
) {
401 if (c
->ndp
== RELAYD_RELAY
&& iface
!= c
) {
402 req
.ndm
.ndm_ifindex
= c
->ifindex
;
403 send(rtnl_event
.uloop
.fd
, &req
, sizeof(req
), MSG_DONTWAIT
);
406 setup_route(addr
, iface
, false);
408 // also: dump to add proxies back in case it moved elsewhere
415 if (iface
->ra
== RELAYD_SERVER
)
416 raise(SIGUSR1
); // Inform about a change in addresses
418 if (iface
->dhcpv6
== RELAYD_SERVER
)
419 iface
->ia_reconf
= true;
424 dump_neigh_table(false);