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>
40 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_rtnl_err(struct odhcpd_event
*e
, int error
);
51 static int ping_socket
= -1;
52 static struct event_socket rtnl_event
= {
54 .uloop
= {.fd
= - 1, },
56 .handle_error
= catch_rtnl_err
,
57 .recv_msgs
= handle_rtnl_event
,
60 .sock_bufsize
= 133120,
63 // Filter ICMPv6 messages of type neighbor soliciation
64 static struct sock_filter bpf
[] = {
65 BPF_STMT(BPF_LD
| BPF_B
| BPF_ABS
, offsetof(struct ip6_hdr
, ip6_nxt
)),
66 BPF_JUMP(BPF_JMP
| BPF_JEQ
| BPF_K
, IPPROTO_ICMPV6
, 0, 3),
67 BPF_STMT(BPF_LD
| BPF_B
| BPF_ABS
, sizeof(struct ip6_hdr
) +
68 offsetof(struct icmp6_hdr
, icmp6_type
)),
69 BPF_JUMP(BPF_JMP
| BPF_JEQ
| BPF_K
, ND_NEIGHBOR_SOLICIT
, 0, 1),
70 BPF_STMT(BPF_RET
| BPF_K
, 0xffffffff),
71 BPF_STMT(BPF_RET
| BPF_K
, 0),
73 static const struct sock_fprog bpf_prog
= {sizeof(bpf
) / sizeof(*bpf
), bpf
};
76 // Initialize NDP-proxy
81 rtnl_event
.sock
= odhcpd_create_nl_socket(NETLINK_ROUTE
);
85 rtnl_event
.ev
.uloop
.fd
= nl_socket_get_fd(rtnl_event
.sock
);
87 if (nl_socket_set_buffer_size(rtnl_event
.sock
, rtnl_event
.sock_bufsize
, 0))
90 nl_socket_disable_seq_check(rtnl_event
.sock
);
92 nl_socket_modify_cb(rtnl_event
.sock
, NL_CB_VALID
, NL_CB_CUSTOM
,
95 // Receive IPv6 address, IPv6 routes and neighbor events
96 if (nl_socket_add_memberships(rtnl_event
.sock
, RTNLGRP_IPV6_IFADDR
,
97 RTNLGRP_IPV6_ROUTE
, RTNLGRP_NEIGH
, 0))
100 odhcpd_register(&rtnl_event
.ev
);
102 // Open ICMPv6 socket
103 ping_socket
= socket(AF_INET6
, SOCK_RAW
| SOCK_CLOEXEC
, IPPROTO_ICMPV6
);
104 if (ping_socket
< 0) {
105 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(bool v6
)
155 struct ifaddrmsg ifa
= {
156 .ifa_family
= v6
? AF_INET6
: AF_INET
,
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 bool dump_neigh
= false;
176 snprintf(procbuf
, sizeof(procbuf
), "/proc/sys/net/ipv6/conf/%s/proxy_ndp", iface
->ifname
);
177 procfd
= open(procbuf
, O_WRONLY
);
184 if (iface
->ndp_event
.uloop
.fd
> 0) {
185 uloop_fd_delete(&iface
->ndp_event
.uloop
);
186 close(iface
->ndp_event
.uloop
.fd
);
187 iface
->ndp_event
.uloop
.fd
= -1;
189 if (!enable
|| iface
->ndp
!= RELAYD_RELAY
)
190 if (write(procfd
, "0\n", 2) < 0) {}
195 if (enable
&& iface
->ndp
== RELAYD_RELAY
) {
196 if (write(procfd
, "1\n", 2) < 0) {}
198 int sock
= socket(AF_PACKET
, SOCK_DGRAM
| SOCK_CLOEXEC
, htons(ETH_P_IPV6
));
200 syslog(LOG_ERR
, "Unable to open packet socket: %s",
206 #ifdef PACKET_RECV_TYPE
207 int pktt
= 1 << PACKET_MULTICAST
;
208 setsockopt(sock
, SOL_PACKET
, PACKET_RECV_TYPE
, &pktt
, sizeof(pktt
));
211 if (setsockopt(sock
, SOL_SOCKET
, SO_ATTACH_FILTER
,
212 &bpf_prog
, sizeof(bpf_prog
))) {
213 syslog(LOG_ERR
, "Failed to set BPF: %s", strerror(errno
));
218 struct sockaddr_ll ll
= {
219 .sll_family
= AF_PACKET
,
220 .sll_ifindex
= iface
->ifindex
,
221 .sll_protocol
= htons(ETH_P_IPV6
),
227 bind(sock
, (struct sockaddr
*)&ll
, sizeof(ll
));
229 struct packet_mreq mreq
= {iface
->ifindex
, PACKET_MR_ALLMULTI
, ETH_ALEN
, {0}};
230 setsockopt(sock
, SOL_PACKET
, PACKET_ADD_MEMBERSHIP
, &mreq
, sizeof(mreq
));
232 iface
->ndp_event
.uloop
.fd
= sock
;
233 iface
->ndp_event
.handle_dgram
= handle_solicit
;
234 odhcpd_register(&iface
->ndp_event
);
236 // If we already were enabled dump is unnecessary, if not do dump
238 dump_neigh_table(false);
244 dump_neigh_table(true);
254 // Send an ICMP-ECHO. This is less for actually pinging but for the
255 // neighbor cache to be kept up-to-date.
256 static void ping6(struct in6_addr
*addr
,
257 const struct interface
*iface
)
259 struct sockaddr_in6 dest
= { .sin6_family
= AF_INET6
, .sin6_addr
= *addr
, .sin6_scope_id
= iface
->ifindex
, };
260 struct icmp6_hdr echo
= { .icmp6_type
= ICMP6_ECHO_REQUEST
};
261 struct iovec iov
= { .iov_base
= &echo
, .iov_len
= sizeof(echo
) };
262 char ipbuf
[INET6_ADDRSTRLEN
];
264 inet_ntop(AF_INET6
, addr
, ipbuf
, sizeof(ipbuf
));
265 syslog(LOG_NOTICE
, "Pinging for %s%%%s", ipbuf
, iface
->ifname
);
267 odhcpd_setup_route(addr
, 128, iface
, NULL
, 128, true);
268 odhcpd_send(ping_socket
, &dest
, &iov
, 1, iface
);
269 odhcpd_setup_route(addr
, 128, iface
, NULL
, 128, false);
272 // Handle solicitations
273 static void handle_solicit(void *addr
, void *data
, size_t len
,
274 struct interface
*iface
, _unused
void *dest
)
276 struct ip6_hdr
*ip6
= data
;
277 struct nd_neighbor_solicit
*req
= (struct nd_neighbor_solicit
*)&ip6
[1];
278 struct sockaddr_ll
*ll
= addr
;
279 char ipbuf
[INET6_ADDRSTRLEN
];
282 // Solicitation is for duplicate address detection
283 bool ns_is_dad
= IN6_IS_ADDR_UNSPECIFIED(&ip6
->ip6_src
);
285 // Don't process solicit messages on non relay interfaces
286 // Don't forward any non-DAD solicitation for external ifaces
287 // TODO: check if we should even forward DADs for them
288 if (iface
->ndp
!= RELAYD_RELAY
|| (iface
->external
&& !ns_is_dad
))
291 if (len
< sizeof(*ip6
) + sizeof(*req
))
292 return; // Invalid reqicitation
294 if (IN6_IS_ADDR_LINKLOCAL(&req
->nd_ns_target
) ||
295 IN6_IS_ADDR_LOOPBACK(&req
->nd_ns_target
) ||
296 IN6_IS_ADDR_MULTICAST(&req
->nd_ns_target
))
297 return; // Invalid target
299 inet_ntop(AF_INET6
, &req
->nd_ns_target
, ipbuf
, sizeof(ipbuf
));
300 syslog(LOG_DEBUG
, "Got a NS for %s%%%s", ipbuf
, iface
->ifname
);
302 odhcpd_get_mac(iface
, mac
);
303 if (!memcmp(ll
->sll_addr
, mac
, sizeof(mac
)))
304 return; // Looped back
307 list_for_each_entry(c
, &interfaces
, head
)
308 if (iface
!= c
&& c
->ndp
== RELAYD_RELAY
&&
309 (ns_is_dad
|| !c
->external
))
310 ping6(&req
->nd_ns_target
, c
);
313 // Use rtnetlink to modify kernel routes
314 static void setup_route(struct in6_addr
*addr
, struct interface
*iface
, bool add
)
316 char ipbuf
[INET6_ADDRSTRLEN
];
318 inet_ntop(AF_INET6
, addr
, ipbuf
, sizeof(ipbuf
));
319 syslog(LOG_NOTICE
, "%s about %s%%%s",
320 (add
) ? "Learned" : "Forgot", ipbuf
, iface
->ifname
);
322 if (iface
->learn_routes
)
323 odhcpd_setup_route(addr
, 128, iface
, NULL
, 1024, add
);
326 // Check address update
327 static void check_addr6_updates(struct interface
*iface
)
329 struct odhcpd_ipaddr
*addr
= NULL
;
330 ssize_t len
= odhcpd_get_interface_addresses(iface
->ifindex
, true, &addr
);
335 bool change
= len
!= (ssize_t
)iface
->ia_addr_len
;
336 for (ssize_t i
= 0; !change
&& i
< len
; ++i
)
337 if (!IN6_ARE_ADDR_EQUAL(&addr
[i
].addr
.in6
, &iface
->ia_addr
[i
].addr
.in6
) ||
338 (addr
[i
].preferred
> 0) != (iface
->ia_addr
[i
].preferred
> 0) ||
339 addr
[i
].valid
< iface
->ia_addr
[i
].valid
||
340 addr
[i
].preferred
< iface
->ia_addr
[i
].preferred
)
344 dhcpv6_ia_preupdate(iface
);
346 free(iface
->ia_addr
);
347 iface
->ia_addr
= addr
;
348 iface
->ia_addr_len
= len
;
351 dhcpv6_ia_postupdate(iface
);
354 syslog(LOG_INFO
, "Raising SIGUSR1 due to address change on %s", iface
->ifname
);
359 static void setup_addr_for_relaying(struct in6_addr
*addr
, struct interface
*iface
, bool add
)
362 char ipbuf
[INET6_ADDRSTRLEN
];
364 inet_ntop(AF_INET6
, addr
, ipbuf
, sizeof(ipbuf
));
366 list_for_each_entry(c
, &interfaces
, head
) {
367 if (iface
== c
|| (c
->ndp
!= RELAYD_RELAY
&& !add
))
370 bool neigh_add
= (c
->ndp
== RELAYD_RELAY
? add
: false);
372 if (odhcpd_setup_proxy_neigh(addr
, c
, neigh_add
))
373 syslog(LOG_DEBUG
, "Failed to %s proxy neighbour entry %s%%%s",
374 neigh_add
? "add" : "delete", ipbuf
, c
->ifname
);
376 syslog(LOG_DEBUG
, "%s proxy neighbour entry %s%%%s",
377 neigh_add
? "Added" : "Deleted", ipbuf
, c
->ifname
);
381 static void handle_rtnl_event(struct odhcpd_event
*e
)
383 struct event_socket
*ev_sock
= container_of(e
, struct event_socket
, ev
);
385 nl_recvmsgs_default(ev_sock
->sock
);
389 // Handler for neighbor cache entries from the kernel. This is our source
390 // to learn and unlearn hosts on interfaces.
391 static int cb_rtnl_valid(struct nl_msg
*msg
, _unused
void *arg
)
393 struct nlmsghdr
*hdr
= nlmsg_hdr(msg
);
394 struct in6_addr
*addr
= NULL
;
395 struct interface
*iface
= NULL
;
397 char ipbuf
[INET6_ADDRSTRLEN
];
399 switch (hdr
->nlmsg_type
) {
402 struct rtmsg
*rtm
= nlmsg_data(hdr
);
404 if (!nlmsg_valid_hdr(hdr
, sizeof(*rtm
)) ||
405 rtm
->rtm_family
!= AF_INET6
)
408 if (rtm
->rtm_dst_len
== 0) {
409 syslog(LOG_INFO
, "Raising SIGUSR1 due to default route change");
419 struct ifaddrmsg
*ifa
= nlmsg_data(hdr
);
420 struct nlattr
*nla
[__IFA_MAX
];
422 if (!nlmsg_valid_hdr(hdr
, sizeof(*ifa
)) ||
423 ifa
->ifa_family
!= AF_INET6
)
426 iface
= odhcpd_get_interface_by_index(ifa
->ifa_index
);
430 nlmsg_parse(hdr
, sizeof(*ifa
), nla
, __IFA_MAX
- 1, NULL
);
431 if (!nla
[IFA_ADDRESS
])
434 addr
= nla_data(nla
[IFA_ADDRESS
]);
435 if (!addr
|| IN6_IS_ADDR_LINKLOCAL(addr
) ||
436 IN6_IS_ADDR_MULTICAST(addr
))
439 inet_ntop(AF_INET6
, addr
, ipbuf
, sizeof(ipbuf
));
440 syslog(LOG_DEBUG
, "Netlink %s %s%%%s", true ? "newaddr" : "deladdr",
441 ipbuf
, iface
->ifname
);
443 check_addr6_updates(iface
);
445 if (iface
->ndp
!= RELAYD_RELAY
)
448 /* handle the relay logic below */
449 setup_addr_for_relaying(addr
, iface
, add
);
452 dump_neigh_table(false);
460 struct ndmsg
*ndm
= nlmsg_data(hdr
);
461 struct nlattr
*nla
[__NDA_MAX
];
463 if (!nlmsg_valid_hdr(hdr
, sizeof(*ndm
)) ||
464 ndm
->ndm_family
!= AF_INET6
)
467 iface
= odhcpd_get_interface_by_index(ndm
->ndm_ifindex
);
468 if (!iface
|| iface
->ndp
!= RELAYD_RELAY
)
469 return (iface
? NL_OK
: NL_SKIP
);
471 nlmsg_parse(hdr
, sizeof(*ndm
), nla
, __NDA_MAX
- 1, NULL
);
475 addr
= nla_data(nla
[NDA_DST
]);
476 if (!addr
|| IN6_IS_ADDR_LINKLOCAL(addr
) ||
477 IN6_IS_ADDR_MULTICAST(addr
))
480 inet_ntop(AF_INET6
, addr
, ipbuf
, sizeof(ipbuf
));
481 syslog(LOG_DEBUG
, "Netlink %s %s%%%s", true ? "newneigh" : "delneigh",
482 ipbuf
, iface
->ifname
);
484 if (ndm
->ndm_flags
& NTF_PROXY
) {
485 /* Dump and flush proxy entries */
486 if (hdr
->nlmsg_type
== RTM_NEWNEIGH
) {
487 odhcpd_setup_proxy_neigh(addr
, iface
, false);
488 setup_route(addr
, iface
, false);
489 dump_neigh_table(false);
495 if (add
&& !(ndm
->ndm_state
&
496 (NUD_REACHABLE
| NUD_STALE
| NUD_DELAY
| NUD_PROBE
|
497 NUD_PERMANENT
| NUD_NOARP
)))
500 setup_addr_for_relaying(addr
, iface
, add
);
501 setup_route(addr
, iface
, add
);
504 dump_neigh_table(false);
515 static void catch_rtnl_err(struct odhcpd_event
*e
, int error
)
517 struct event_socket
*ev_sock
= container_of(e
, struct event_socket
, ev
);
519 if (error
!= ENOBUFS
)
522 /* Double netlink event buffer size */
523 ev_sock
->sock_bufsize
*= 2;
525 if (nl_socket_set_buffer_size(ev_sock
->sock
, ev_sock
->sock_bufsize
, 0))
528 dump_addr_table(true);
532 odhcpd_deregister(e
);