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
);
40 static ssize_t
ping6(struct in6_addr
*addr
,
41 const struct interface
*iface
);
43 static uint32_t rtnl_seqid
= 0;
44 static int ping_socket
= -1;
45 static struct odhcpd_event rtnl_event
= {{.fd
= -1}, handle_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
64 // Setup netlink socket
65 if ((rtnl_event
.uloop
.fd
= odhcpd_open_rtnl()) < 0)
68 // Receive netlink neighbor and ip-address events
69 uint32_t group
= RTNLGRP_IPV6_IFADDR
;
70 setsockopt(rtnl_event
.uloop
.fd
, SOL_NETLINK
,
71 NETLINK_ADD_MEMBERSHIP
, &group
, sizeof(group
));
72 group
= RTNLGRP_IPV6_ROUTE
;
73 setsockopt(rtnl_event
.uloop
.fd
, SOL_NETLINK
,
74 NETLINK_ADD_MEMBERSHIP
, &group
, sizeof(group
));
76 odhcpd_register(&rtnl_event
);
79 ping_socket
= socket(AF_INET6
, SOCK_RAW
| SOCK_CLOEXEC
, IPPROTO_ICMPV6
);
80 if (ping_socket
< 0) {
81 syslog(LOG_ERR
, "Unable to open raw socket: %s", strerror(errno
));
86 setsockopt(ping_socket
, IPPROTO_RAW
, IPV6_CHECKSUM
, &val
, sizeof(val
));
88 // This is required by RFC 4861
90 setsockopt(ping_socket
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
));
91 setsockopt(ping_socket
, IPPROTO_IPV6
, IPV6_UNICAST_HOPS
, &val
, sizeof(val
));
93 // Filter all packages, we only want to send
94 struct icmp6_filter filt
;
95 ICMP6_FILTER_SETBLOCKALL(&filt
);
96 setsockopt(ping_socket
, IPPROTO_ICMPV6
, ICMP6_FILTER
, &filt
, sizeof(filt
));
99 // Netlink socket, continued...
100 group
= RTNLGRP_NEIGH
;
101 setsockopt(rtnl_event
.uloop
.fd
, SOL_NETLINK
, NETLINK_ADD_MEMBERSHIP
, &group
, sizeof(group
));
107 static void dump_neigh_table(bool proxy
)
113 {sizeof(req
), RTM_GETNEIGH
, NLM_F_REQUEST
| NLM_F_DUMP
,
115 {.ndm_family
= AF_INET6
, .ndm_flags
= (proxy
) ? NTF_PROXY
: 0}
117 send(rtnl_event
.uloop
.fd
, &req
, sizeof(req
), MSG_DONTWAIT
);
121 int setup_ndp_interface(struct interface
*iface
, bool enable
)
124 snprintf(procbuf
, sizeof(procbuf
), "/proc/sys/net/ipv6/conf/%s/proxy_ndp", iface
->ifname
);
125 int procfd
= open(procbuf
, O_WRONLY
);
126 bool dump_neigh
= false;
128 if (iface
->ndp_event
.uloop
.fd
>= 0) {
129 uloop_fd_delete(&iface
->ndp_event
.uloop
);
130 close(iface
->ndp_event
.uloop
.fd
);
131 iface
->ndp_event
.uloop
.fd
= -1;
133 write(procfd
, "0\n", 2);
137 if (enable
&& (iface
->ra
== RELAYD_SERVER
|| iface
->dhcpv6
== RELAYD_SERVER
)) {
138 // Synthesize initial address events
141 struct ifaddrmsg ifa
;
143 {sizeof(req2
), RTM_GETADDR
, NLM_F_REQUEST
| NLM_F_DUMP
,
145 {.ifa_family
= AF_INET6
, .ifa_index
= iface
->ifindex
}
147 send(rtnl_event
.uloop
.fd
, &req2
, sizeof(req2
), MSG_DONTWAIT
);
150 if (enable
&& iface
->ndp
== RELAYD_RELAY
) {
151 write(procfd
, "1\n", 2);
153 int sock
= socket(AF_PACKET
, SOCK_DGRAM
| SOCK_CLOEXEC
, htons(ETH_P_IPV6
));
155 syslog(LOG_ERR
, "Unable to open packet socket: %s",
160 #ifdef PACKET_RECV_TYPE
161 int pktt
= 1 << PACKET_MULTICAST
;
162 setsockopt(sock
, SOL_PACKET
, PACKET_RECV_TYPE
, &pktt
, sizeof(pktt
));
165 if (setsockopt(sock
, SOL_SOCKET
, SO_ATTACH_FILTER
,
166 &bpf_prog
, sizeof(bpf_prog
))) {
167 syslog(LOG_ERR
, "Failed to set BPF: %s", strerror(errno
));
171 struct sockaddr_ll ll
= {
172 .sll_family
= AF_PACKET
,
173 .sll_ifindex
= iface
->ifindex
,
174 .sll_protocol
= htons(ETH_P_IPV6
),
180 bind(sock
, (struct sockaddr
*)&ll
, sizeof(ll
));
182 struct packet_mreq mreq
= {iface
->ifindex
, PACKET_MR_ALLMULTI
, ETH_ALEN
, {0}};
183 setsockopt(sock
, SOL_PACKET
, PACKET_ADD_MEMBERSHIP
, &mreq
, sizeof(mreq
));
185 iface
->ndp_event
.uloop
.fd
= sock
;
186 iface
->ndp_event
.handle_dgram
= handle_solicit
;
187 odhcpd_register(&iface
->ndp_event
);
189 // If we already were enabled dump is unnecessary, if not do dump
191 dump_neigh_table(false);
198 dump_neigh_table(true);
204 // Send an ICMP-ECHO. This is less for actually pinging but for the
205 // neighbor cache to be kept up-to-date.
206 static ssize_t
ping6(struct in6_addr
*addr
,
207 const struct interface
*iface
)
209 struct sockaddr_in6 dest
= {AF_INET6
, 0, 0, *addr
, 0};
210 struct icmp6_hdr echo
= {.icmp6_type
= ICMP6_ECHO_REQUEST
};
211 struct iovec iov
= {&echo
, sizeof(echo
)};
213 // Linux seems to not honor IPV6_PKTINFO on raw-sockets, so work around
214 setsockopt(ping_socket
, SOL_SOCKET
, SO_BINDTODEVICE
,
215 iface
->ifname
, sizeof(iface
->ifname
));
216 return odhcpd_send(ping_socket
, &dest
, &iov
, 1, iface
);
220 // Handle solicitations
221 static void handle_solicit(void *addr
, void *data
, size_t len
,
222 struct interface
*iface
, _unused
void *dest
)
224 struct ip6_hdr
*ip6
= data
;
225 struct nd_neighbor_solicit
*req
= (struct nd_neighbor_solicit
*)&ip6
[1];
226 struct sockaddr_ll
*ll
= addr
;
228 // Solicitation is for duplicate address detection
229 bool ns_is_dad
= IN6_IS_ADDR_UNSPECIFIED(&ip6
->ip6_src
);
231 // Don't forward any non-DAD solicitation for external ifaces
232 // TODO: check if we should even forward DADs for them
233 if (iface
->external
&& !ns_is_dad
)
236 if (len
< sizeof(*ip6
) + sizeof(*req
))
237 return; // Invalid reqicitation
239 if (IN6_IS_ADDR_LINKLOCAL(&req
->nd_ns_target
) ||
240 IN6_IS_ADDR_LOOPBACK(&req
->nd_ns_target
) ||
241 IN6_IS_ADDR_MULTICAST(&req
->nd_ns_target
))
242 return; // Invalid target
244 char ipbuf
[INET6_ADDRSTRLEN
];
245 inet_ntop(AF_INET6
, &req
->nd_ns_target
, ipbuf
, sizeof(ipbuf
));
246 syslog(LOG_DEBUG
, "Got a NS for %s", ipbuf
);
249 odhcpd_get_mac(iface
, mac
);
250 if (!memcmp(ll
->sll_addr
, mac
, sizeof(mac
)))
251 return; // Looped back
254 list_for_each_entry(c
, &interfaces
, head
)
255 if (iface
->ndp
== RELAYD_RELAY
&& iface
!= c
&&
256 (!ns_is_dad
|| !c
->external
== false))
257 ping6(&req
->nd_ns_target
, c
);
261 void odhcpd_setup_route(const struct in6_addr
*addr
, int prefixlen
,
262 const struct interface
*iface
, const struct in6_addr
*gw
, bool add
)
267 struct rtattr rta_dst
;
268 struct in6_addr dst_addr
;
269 struct rtattr rta_oif
;
271 struct rtattr rta_table
;
273 struct rtattr rta_gw
;
276 {sizeof(req
), 0, NLM_F_REQUEST
, ++rtnl_seqid
, 0},
277 {AF_INET6
, prefixlen
, 0, 0, 0, 0, 0, 0, 0},
278 {sizeof(struct rtattr
) + sizeof(struct in6_addr
), RTA_DST
},
280 {sizeof(struct rtattr
) + sizeof(uint32_t), RTA_OIF
},
282 {sizeof(struct rtattr
) + sizeof(uint32_t), RTA_TABLE
},
284 {sizeof(struct rtattr
) + sizeof(struct in6_addr
), RTA_GATEWAY
},
292 req
.nh
.nlmsg_type
= RTM_NEWROUTE
;
293 req
.nh
.nlmsg_flags
|= (NLM_F_CREATE
| NLM_F_REPLACE
);
294 req
.rtm
.rtm_protocol
= RTPROT_BOOT
;
295 req
.rtm
.rtm_scope
= (gw
) ? RT_SCOPE_UNIVERSE
: RT_SCOPE_LINK
;
296 req
.rtm
.rtm_type
= RTN_UNICAST
;
298 req
.nh
.nlmsg_type
= RTM_DELROUTE
;
299 req
.rtm
.rtm_scope
= RT_SCOPE_NOWHERE
;
302 size_t reqlen
= (gw
) ? sizeof(req
) : offsetof(struct req
, rta_gw
);
303 send(rtnl_event
.uloop
.fd
, &req
, reqlen
, MSG_DONTWAIT
);
306 // Use rtnetlink to modify kernel routes
307 static void setup_route(struct in6_addr
*addr
, struct interface
*iface
,
310 char namebuf
[INET6_ADDRSTRLEN
];
311 inet_ntop(AF_INET6
, addr
, namebuf
, sizeof(namebuf
));
312 syslog(LOG_NOTICE
, "%s about %s on %s", (add
) ? "Learned" : "Forgot",
313 namebuf
, (iface
) ? iface
->ifname
: "<pending>");
315 if (!iface
|| !iface
->learn_routes
)
318 odhcpd_setup_route(addr
, 128, iface
, NULL
, add
);
322 // Handler for neighbor cache entries from the kernel. This is our source
323 // to learn and unlearn hosts on interfaces.
324 static void handle_rtnetlink(_unused
void *addr
, void *data
, size_t len
,
325 _unused
struct interface
*iface
, _unused
void *dest
)
327 bool dump_neigh
= false;
328 struct in6_addr last_solicited
= IN6ADDR_ANY_INIT
;
330 for (struct nlmsghdr
*nh
= data
; NLMSG_OK(nh
, len
);
331 nh
= NLMSG_NEXT(nh
, len
)) {
332 struct rtmsg
*rtm
= NLMSG_DATA(nh
);
333 if ((nh
->nlmsg_type
== RTM_NEWROUTE
||
334 nh
->nlmsg_type
== RTM_DELROUTE
) &&
335 rtm
->rtm_dst_len
== 0)
336 raise(SIGUSR1
); // Inform about a change in default route
338 struct ndmsg
*ndm
= NLMSG_DATA(nh
);
339 struct ifaddrmsg
*ifa
= NLMSG_DATA(nh
);
340 if (nh
->nlmsg_type
!= RTM_NEWNEIGH
341 && nh
->nlmsg_type
!= RTM_DELNEIGH
342 && nh
->nlmsg_type
!= RTM_NEWADDR
343 && nh
->nlmsg_type
!= RTM_DELADDR
)
344 continue; // Unrelated message type
345 bool is_addr
= (nh
->nlmsg_type
== RTM_NEWADDR
346 || nh
->nlmsg_type
== RTM_DELADDR
);
348 // Family and ifindex are on the same offset for NEIGH and ADDR
349 if (NLMSG_PAYLOAD(nh
, 0) < sizeof(*ndm
)
350 || ndm
->ndm_family
!= AF_INET6
)
354 struct interface
*iface
;
355 if (!(iface
= odhcpd_get_interface_by_index(ndm
->ndm_ifindex
)))
359 size_t rta_offset
= (is_addr
) ? sizeof(*ifa
) : sizeof(*ndm
);
360 uint16_t atype
= (is_addr
) ? IFA_ADDRESS
: NDA_DST
;
361 ssize_t alen
= NLMSG_PAYLOAD(nh
, rta_offset
);
362 struct in6_addr
*addr
= NULL
;
364 for (struct rtattr
*rta
= (void*)(((uint8_t*)ndm
) + rta_offset
);
365 RTA_OK(rta
, alen
); rta
= RTA_NEXT(rta
, alen
))
366 if (rta
->rta_type
== atype
&&
367 RTA_PAYLOAD(rta
) >= sizeof(*addr
))
368 addr
= RTA_DATA(rta
);
370 // Address not specified or unrelated
371 if (!addr
|| IN6_IS_ADDR_LINKLOCAL(addr
) ||
372 IN6_IS_ADDR_MULTICAST(addr
))
378 add
= (nh
->nlmsg_type
== RTM_NEWADDR
);
380 add
= (nh
->nlmsg_type
== RTM_NEWNEIGH
&& (ndm
->ndm_state
&
381 (NUD_REACHABLE
| NUD_STALE
| NUD_DELAY
| NUD_PROBE
382 | NUD_PERMANENT
| NUD_NOARP
)));
384 if (iface
->ndp
== RELAYD_RELAY
) {
385 // Replay change to all neighbor cache
389 struct nlattr nla_dst
;
392 {sizeof(req
), RTM_DELNEIGH
, NLM_F_REQUEST
,
394 {.ndm_family
= AF_INET6
, .ndm_flags
= NTF_PROXY
},
395 {sizeof(struct nlattr
) + sizeof(struct in6_addr
), NDA_DST
},
399 if (ndm
->ndm_flags
& NTF_PROXY
) {
400 // Dump & flush proxy entries
401 if (nh
->nlmsg_type
== RTM_NEWNEIGH
) {
402 req
.ndm
.ndm_ifindex
= iface
->ifindex
;
403 send(rtnl_event
.uloop
.fd
, &req
, sizeof(req
), MSG_DONTWAIT
);
408 list_for_each_entry(c
, &interfaces
, head
) {
412 if (c
->ndp
== RELAYD_RELAY
) {
413 req
.nh
.nlmsg_type
= RTM_NEWNEIGH
;
414 req
.nh
.nlmsg_flags
|= NLM_F_CREATE
| NLM_F_REPLACE
;
416 req
.ndm
.ndm_ifindex
= c
->ifindex
;
417 send(rtnl_event
.uloop
.fd
, &req
, sizeof(req
), MSG_DONTWAIT
);
418 } else { // Delete NDP cache from interfaces without relay
419 req
.nh
.nlmsg_type
= RTM_DELNEIGH
;
420 req
.nh
.nlmsg_flags
&= ~(NLM_F_CREATE
| NLM_F_REPLACE
);
422 req
.ndm
.ndm_ifindex
= c
->ifindex
;
423 send(rtnl_event
.uloop
.fd
, &req
, sizeof(req
), MSG_DONTWAIT
);
427 setup_route(addr
, iface
, true);
429 if (nh
->nlmsg_type
== RTM_NEWNEIGH
) {
430 // might be locally originating
431 if (!IN6_ARE_ADDR_EQUAL(&last_solicited
, addr
)) {
432 last_solicited
= *addr
;
435 list_for_each_entry(c
, &interfaces
, head
)
436 if (iface
->ndp
== RELAYD_RELAY
&& iface
!= c
&&
437 !c
->external
== false)
442 list_for_each_entry(c
, &interfaces
, head
) {
443 if (c
->ndp
== RELAYD_RELAY
&& iface
!= c
) {
444 req
.ndm
.ndm_ifindex
= c
->ifindex
;
445 send(rtnl_event
.uloop
.fd
, &req
, sizeof(req
), MSG_DONTWAIT
);
448 setup_route(addr
, iface
, false);
450 // also: dump to add proxies back in case it moved elsewhere
457 if (iface
->ra
== RELAYD_SERVER
)
458 raise(SIGUSR1
); // Inform about a change in addresses
460 if (iface
->dhcpv6
== RELAYD_SERVER
)
461 iface
->ia_reconf
= true;
463 if (iface
->ndp
== RELAYD_RELAY
&& iface
->master
) {
464 // Replay address changes on all slave interfaces
465 nh
->nlmsg_flags
= NLM_F_REQUEST
;
467 if (nh
->nlmsg_type
== RTM_NEWADDR
)
468 nh
->nlmsg_flags
|= NLM_F_CREATE
| NLM_F_REPLACE
;
471 list_for_each_entry(c
, &interfaces
, head
) {
472 if (c
->ndp
== RELAYD_RELAY
&& !c
->master
) {
473 ifa
->ifa_index
= c
->ifindex
;
474 send(rtnl_event
.uloop
.fd
, nh
, nh
->nlmsg_len
, MSG_DONTWAIT
);
482 dump_neigh_table(false);