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>
32 #include <netlink/msg.h>
33 #include <netlink/socket.h>
34 #include <netlink/attr.h>
41 struct odhcpd_event ev
;
45 static void handle_solicit(void *addr
, void *data
, size_t len
,
46 struct interface
*iface
, void *dest
);
47 static void handle_rtnl_event(struct odhcpd_event
*ev
);
48 static int cb_rtnl_valid(struct nl_msg
*msg
, void *arg
);
49 static void catch_rtnetlink(int error
);
51 static int ping_socket
= -1;
52 static struct event_socket rtnl_event
= {
54 .uloop
= {.fd
= - 1, },
56 .handle_error
= catch_rtnetlink
,
57 .recv_msgs
= handle_rtnl_event
,
62 // Filter ICMPv6 messages of type neighbor soliciation
63 static struct sock_filter bpf
[] = {
64 BPF_STMT(BPF_LD
| BPF_B
| BPF_ABS
, offsetof(struct ip6_hdr
, ip6_nxt
)),
65 BPF_JUMP(BPF_JMP
| BPF_JEQ
| BPF_K
, IPPROTO_ICMPV6
, 0, 3),
66 BPF_STMT(BPF_LD
| BPF_B
| BPF_ABS
, sizeof(struct ip6_hdr
) +
67 offsetof(struct icmp6_hdr
, icmp6_type
)),
68 BPF_JUMP(BPF_JMP
| BPF_JEQ
| BPF_K
, ND_NEIGHBOR_SOLICIT
, 0, 1),
69 BPF_STMT(BPF_RET
| BPF_K
, 0xffffffff),
70 BPF_STMT(BPF_RET
| BPF_K
, 0),
72 static const struct sock_fprog bpf_prog
= {sizeof(bpf
) / sizeof(*bpf
), bpf
};
75 // Initialize NDP-proxy
80 rtnl_event
.sock
= odhcpd_create_nl_socket(NETLINK_ROUTE
);
84 rtnl_event
.ev
.uloop
.fd
= nl_socket_get_fd(rtnl_event
.sock
);
86 if (nl_socket_set_buffer_size(rtnl_event
.sock
, val
, 0))
89 nl_socket_disable_seq_check(rtnl_event
.sock
);
91 nl_socket_modify_cb(rtnl_event
.sock
, NL_CB_VALID
, NL_CB_CUSTOM
,
94 // Receive IPv6 address, IPv6 routes and neighbor events
95 if (nl_socket_add_memberships(rtnl_event
.sock
, RTNLGRP_IPV6_IFADDR
,
96 RTNLGRP_IPV6_ROUTE
, RTNLGRP_NEIGH
, 0))
99 odhcpd_register(&rtnl_event
.ev
);
101 // Open ICMPv6 socket
102 ping_socket
= socket(AF_INET6
, SOCK_RAW
| SOCK_CLOEXEC
, IPPROTO_ICMPV6
);
103 if (ping_socket
< 0) {
104 syslog(LOG_ERR
, "Unable to open raw socket: %s", strerror(errno
));
109 setsockopt(ping_socket
, IPPROTO_RAW
, IPV6_CHECKSUM
, &val
, sizeof(val
));
111 // This is required by RFC 4861
113 setsockopt(ping_socket
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
));
114 setsockopt(ping_socket
, IPPROTO_IPV6
, IPV6_UNICAST_HOPS
, &val
, sizeof(val
));
116 // Filter all packages, we only want to send
117 struct icmp6_filter filt
;
118 ICMP6_FILTER_SETBLOCKALL(&filt
);
119 setsockopt(ping_socket
, IPPROTO_ICMPV6
, ICMP6_FILTER
, &filt
, sizeof(filt
));
124 if (rtnl_event
.sock
) {
125 nl_socket_free(rtnl_event
.sock
);
126 rtnl_event
.sock
= NULL
;
127 rtnl_event
.ev
.uloop
.fd
= -1;
133 static void dump_neigh_table(const bool proxy
)
137 .ndm_family
= AF_INET6
,
138 .ndm_flags
= proxy
? NTF_PROXY
: 0,
141 msg
= nlmsg_alloc_simple(RTM_GETNEIGH
, NLM_F_REQUEST
| NLM_F_DUMP
);
145 nlmsg_append(msg
, &ndm
, sizeof(ndm
), 0);
147 nl_send_auto_complete(rtnl_event
.sock
, msg
);
152 static void dump_addr_table(void)
155 struct ifaddrmsg ifa
= {
156 .ifa_family
= AF_INET6
,
159 msg
= nlmsg_alloc_simple(RTM_GETADDR
, NLM_F_REQUEST
| NLM_F_DUMP
);
163 nlmsg_append(msg
, &ifa
, sizeof(ifa
), 0);
165 nl_send_auto_complete(rtnl_event
.sock
, msg
);
170 int setup_ndp_interface(struct interface
*iface
, bool enable
)
173 snprintf(procbuf
, sizeof(procbuf
), "/proc/sys/net/ipv6/conf/%s/proxy_ndp", iface
->ifname
);
174 int procfd
= open(procbuf
, O_WRONLY
);
175 bool dump_neigh
= false;
177 if (iface
->ndp_event
.uloop
.fd
> 0) {
178 uloop_fd_delete(&iface
->ndp_event
.uloop
);
179 close(iface
->ndp_event
.uloop
.fd
);
180 iface
->ndp_event
.uloop
.fd
= -1;
182 if (!enable
|| iface
->ndp
!= RELAYD_RELAY
)
183 if (write(procfd
, "0\n", 2) < 0) {}
188 if (enable
&& (iface
->ra
== RELAYD_SERVER
||
189 iface
->dhcpv6
== RELAYD_SERVER
|| iface
->ndp
== RELAYD_RELAY
))
192 if (enable
&& iface
->ndp
== RELAYD_RELAY
) {
193 if (write(procfd
, "1\n", 2) < 0) {}
196 int sock
= socket(AF_PACKET
, SOCK_DGRAM
| SOCK_CLOEXEC
, htons(ETH_P_IPV6
));
198 syslog(LOG_ERR
, "Unable to open packet socket: %s",
203 #ifdef PACKET_RECV_TYPE
204 int pktt
= 1 << PACKET_MULTICAST
;
205 setsockopt(sock
, SOL_PACKET
, PACKET_RECV_TYPE
, &pktt
, sizeof(pktt
));
208 if (setsockopt(sock
, SOL_SOCKET
, SO_ATTACH_FILTER
,
209 &bpf_prog
, sizeof(bpf_prog
))) {
210 syslog(LOG_ERR
, "Failed to set BPF: %s", strerror(errno
));
214 struct sockaddr_ll ll
= {
215 .sll_family
= AF_PACKET
,
216 .sll_ifindex
= iface
->ifindex
,
217 .sll_protocol
= htons(ETH_P_IPV6
),
223 bind(sock
, (struct sockaddr
*)&ll
, sizeof(ll
));
225 struct packet_mreq mreq
= {iface
->ifindex
, PACKET_MR_ALLMULTI
, ETH_ALEN
, {0}};
226 setsockopt(sock
, SOL_PACKET
, PACKET_ADD_MEMBERSHIP
, &mreq
, sizeof(mreq
));
228 iface
->ndp_event
.uloop
.fd
= sock
;
229 iface
->ndp_event
.handle_dgram
= handle_solicit
;
230 odhcpd_register(&iface
->ndp_event
);
232 // If we already were enabled dump is unnecessary, if not do dump
234 dump_neigh_table(false);
241 dump_neigh_table(true);
247 // Send an ICMP-ECHO. This is less for actually pinging but for the
248 // neighbor cache to be kept up-to-date.
249 static void ping6(struct in6_addr
*addr
,
250 const struct interface
*iface
)
252 struct sockaddr_in6 dest
= { .sin6_family
= AF_INET6
, .sin6_addr
= *addr
, .sin6_scope_id
= iface
->ifindex
, };
253 struct icmp6_hdr echo
= { .icmp6_type
= ICMP6_ECHO_REQUEST
};
254 struct iovec iov
= { .iov_base
= &echo
, .iov_len
= sizeof(echo
) };
256 odhcpd_setup_route(addr
, 128, iface
, NULL
, 128, true);
257 odhcpd_send(ping_socket
, &dest
, &iov
, 1, iface
);
258 odhcpd_setup_route(addr
, 128, iface
, NULL
, 128, false);
262 // Handle solicitations
263 static void handle_solicit(void *addr
, void *data
, size_t len
,
264 struct interface
*iface
, _unused
void *dest
)
266 struct ip6_hdr
*ip6
= data
;
267 struct nd_neighbor_solicit
*req
= (struct nd_neighbor_solicit
*)&ip6
[1];
268 struct sockaddr_ll
*ll
= addr
;
270 // Solicitation is for duplicate address detection
271 bool ns_is_dad
= IN6_IS_ADDR_UNSPECIFIED(&ip6
->ip6_src
);
273 // Don't process solicit messages on non relay interfaces
274 // Don't forward any non-DAD solicitation for external ifaces
275 // TODO: check if we should even forward DADs for them
276 if (iface
->ndp
!= RELAYD_RELAY
|| (iface
->external
&& !ns_is_dad
))
279 if (len
< sizeof(*ip6
) + sizeof(*req
))
280 return; // Invalid reqicitation
282 if (IN6_IS_ADDR_LINKLOCAL(&req
->nd_ns_target
) ||
283 IN6_IS_ADDR_LOOPBACK(&req
->nd_ns_target
) ||
284 IN6_IS_ADDR_MULTICAST(&req
->nd_ns_target
))
285 return; // Invalid target
287 char ipbuf
[INET6_ADDRSTRLEN
];
288 inet_ntop(AF_INET6
, &req
->nd_ns_target
, ipbuf
, sizeof(ipbuf
));
289 syslog(LOG_DEBUG
, "Got a NS for %s", ipbuf
);
292 odhcpd_get_mac(iface
, mac
);
293 if (!memcmp(ll
->sll_addr
, mac
, sizeof(mac
)))
294 return; // Looped back
297 list_for_each_entry(c
, &interfaces
, head
)
298 if (iface
!= c
&& c
->ndp
== RELAYD_RELAY
&&
299 (ns_is_dad
|| !c
->external
))
300 ping6(&req
->nd_ns_target
, c
);
303 // Use rtnetlink to modify kernel routes
304 static void setup_route(struct in6_addr
*addr
, struct interface
*iface
, bool add
)
306 char namebuf
[INET6_ADDRSTRLEN
];
307 inet_ntop(AF_INET6
, addr
, namebuf
, sizeof(namebuf
));
308 syslog(LOG_NOTICE
, "%s about %s on %s",
309 (add
) ? "Learned" : "Forgot", namebuf
, iface
->ifname
);
311 if (iface
->learn_routes
)
312 odhcpd_setup_route(addr
, 128, iface
, NULL
, 1024, add
);
316 static int prefixcmp(const void *va
, const void *vb
)
318 const struct odhcpd_ipaddr
*a
= va
, *b
= vb
;
319 uint32_t a_pref
= ((a
->addr
.s6_addr
[0] & 0xfe) != 0xfc) ? a
->preferred
: 1;
320 uint32_t b_pref
= ((b
->addr
.s6_addr
[0] & 0xfe) != 0xfc) ? b
->preferred
: 1;
321 return (a_pref
< b_pref
) ? 1 : (a_pref
> b_pref
) ? -1 : 0;
324 // Check address update
325 static void check_addr_updates(struct interface
*iface
)
327 struct odhcpd_ipaddr addr
[RELAYD_MAX_ADDRS
] = {{IN6ADDR_ANY_INIT
, 0, 0, 0, 0}};
328 time_t now
= odhcpd_time();
329 ssize_t len
= odhcpd_get_interface_addresses(iface
->ifindex
, addr
, ARRAY_SIZE(addr
));
334 qsort(addr
, len
, sizeof(*addr
), prefixcmp
);
336 for (int i
= 0; i
< len
; ++i
) {
337 addr
[i
].addr
.s6_addr32
[3] = 0;
339 if (addr
[i
].preferred
< UINT32_MAX
- now
)
340 addr
[i
].preferred
+= now
;
342 if (addr
[i
].valid
< UINT32_MAX
- now
)
343 addr
[i
].valid
+= now
;
346 bool change
= len
!= (ssize_t
)iface
->ia_addr_len
;
347 for (ssize_t i
= 0; !change
&& i
< len
; ++i
)
348 if (!IN6_ARE_ADDR_EQUAL(&addr
[i
].addr
, &iface
->ia_addr
[i
].addr
) ||
349 (addr
[i
].preferred
> 0) != (iface
->ia_addr
[i
].preferred
> 0) ||
350 addr
[i
].valid
< iface
->ia_addr
[i
].valid
||
351 addr
[i
].preferred
< iface
->ia_addr
[i
].preferred
)
355 dhcpv6_ia_preupdate(iface
);
357 memcpy(iface
->ia_addr
, addr
, len
* sizeof(*addr
));
358 iface
->ia_addr_len
= len
;
361 dhcpv6_ia_postupdate(iface
, now
);
364 syslog(LOG_INFO
, "Raising SIGUSR1 due to address change on %s", iface
->ifname
);
369 void setup_addr_for_relaying(struct in6_addr
*addr
, struct interface
*iface
, bool add
)
373 list_for_each_entry(c
, &interfaces
, head
) {
374 if (iface
== c
|| (c
->ndp
!= RELAYD_RELAY
&& !add
))
377 odhcpd_setup_proxy_neigh(addr
, c
, c
->ndp
== RELAYD_RELAY
? add
: false);
381 void setup_ping6(struct in6_addr
*addr
, struct interface
*iface
)
385 list_for_each_entry(c
, &interfaces
, head
) {
386 if (iface
== c
|| c
->ndp
!= RELAYD_RELAY
||
394 static struct in6_addr last_solicited
;
396 static void handle_rtnl_event(struct odhcpd_event
*e
)
398 struct event_socket
*ev_sock
= container_of(e
, struct event_socket
, ev
);
400 nl_recvmsgs_default(ev_sock
->sock
);
404 // Handler for neighbor cache entries from the kernel. This is our source
405 // to learn and unlearn hosts on interfaces.
406 static int cb_rtnl_valid(struct nl_msg
*msg
, _unused
void *arg
)
408 struct nlmsghdr
*hdr
= nlmsg_hdr(msg
);
409 struct in6_addr
*addr
= NULL
;
410 struct interface
*iface
= NULL
;
413 switch (hdr
->nlmsg_type
) {
416 struct rtmsg
*rtm
= nlmsg_data(hdr
);
418 if (!nlmsg_valid_hdr(hdr
, sizeof(*rtm
)) ||
419 rtm
->rtm_family
!= AF_INET6
)
422 if (rtm
->rtm_dst_len
== 0) {
423 syslog(LOG_INFO
, "Raising SIGUSR1 due to default route change");
432 struct ifaddrmsg
*ifa
= nlmsg_data(hdr
);
433 struct nlattr
*nla
[__IFA_MAX
];
435 if (!nlmsg_valid_hdr(hdr
, sizeof(*ifa
)) ||
436 ifa
->ifa_family
!= AF_INET6
)
439 iface
= odhcpd_get_interface_by_index(ifa
->ifa_index
);
443 nlmsg_parse(hdr
, sizeof(*ifa
), nla
, __IFA_MAX
- 1, NULL
);
444 if (!nla
[IFA_ADDRESS
])
447 addr
= nla_data(nla
[IFA_ADDRESS
]);
448 if (!addr
|| IN6_IS_ADDR_LINKLOCAL(addr
) ||
449 IN6_IS_ADDR_MULTICAST(addr
))
452 check_addr_updates(iface
);
454 if (iface
->ndp
!= RELAYD_RELAY
)
457 /* handle the relay logic below */
458 setup_addr_for_relaying(addr
, iface
, add
);
461 dump_neigh_table(false);
468 struct ndmsg
*ndm
= nlmsg_data(hdr
);
469 struct nlattr
*nla
[__NDA_MAX
];
471 if (!nlmsg_valid_hdr(hdr
, sizeof(*ndm
)) ||
472 ndm
->ndm_family
!= AF_INET6
)
475 iface
= odhcpd_get_interface_by_index(ndm
->ndm_ifindex
);
476 if (!iface
|| iface
->ndp
!= RELAYD_RELAY
)
477 return (iface
? NL_OK
: NL_SKIP
);
479 nlmsg_parse(hdr
, sizeof(*ndm
), nla
, __NDA_MAX
- 1, NULL
);
483 addr
= nla_data(nla
[NDA_DST
]);
484 if (!addr
|| IN6_IS_ADDR_LINKLOCAL(addr
) ||
485 IN6_IS_ADDR_MULTICAST(addr
))
488 if (ndm
->ndm_flags
& NTF_PROXY
) {
489 /* Dump and flush proxy entries */
490 if (hdr
->nlmsg_type
== RTM_NEWNEIGH
) {
491 odhcpd_setup_proxy_neigh(addr
, iface
, false);
492 setup_route(addr
, iface
, false);
493 dump_neigh_table(false);
499 if (add
&& !(ndm
->ndm_state
&
500 (NUD_REACHABLE
| NUD_STALE
| NUD_DELAY
| NUD_PROBE
|
501 NUD_PERMANENT
| NUD_NOARP
))) {
502 if (!IN6_ARE_ADDR_EQUAL(&last_solicited
, addr
)) {
503 last_solicited
= *addr
;
504 setup_ping6(addr
, iface
);
510 setup_addr_for_relaying(addr
, iface
, add
);
511 setup_route(addr
, iface
, add
);
514 dump_neigh_table(false);
525 static void catch_rtnetlink(int error
)
527 if (error
== ENOBUFS
)