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);
42 static uint32_t rtnl_seqid = 0;
43 static int ping_socket = -1;
44 static struct odhcpd_event rtnl_event = {{.fd = -1}, handle_rtnetlink};
47 // Filter ICMPv6 messages of type neighbor soliciation
48 static struct sock_filter bpf[] = {
49 BPF_STMT(BPF_LD | BPF_B | BPF_ABS, offsetof(struct ip6_hdr, ip6_nxt)),
50 BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, IPPROTO_ICMPV6, 0, 3),
51 BPF_STMT(BPF_LD | BPF_B | BPF_ABS, sizeof(struct ip6_hdr) +
52 offsetof(struct icmp6_hdr, icmp6_type)),
53 BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, ND_NEIGHBOR_SOLICIT, 0, 1),
54 BPF_STMT(BPF_RET | BPF_K, 0xffffffff),
55 BPF_STMT(BPF_RET | BPF_K, 0),
57 static const struct sock_fprog bpf_prog = {sizeof(bpf) / sizeof(*bpf), bpf};
60 // Initialize NDP-proxy
63 // Setup netlink socket
64 if ((rtnl_event.uloop.fd = odhcpd_open_rtnl()) < 0)
67 // Receive netlink neighbor and ip-address events
68 uint32_t group = RTNLGRP_IPV6_IFADDR;
69 setsockopt(rtnl_event.uloop.fd, SOL_NETLINK,
70 NETLINK_ADD_MEMBERSHIP, &group, sizeof(group));
71 group = RTNLGRP_IPV6_ROUTE;
72 setsockopt(rtnl_event.uloop.fd, SOL_NETLINK,
73 NETLINK_ADD_MEMBERSHIP, &group, sizeof(group));
75 odhcpd_register(&rtnl_event);
78 ping_socket = socket(AF_INET6, SOCK_RAW | SOCK_CLOEXEC, IPPROTO_ICMPV6);
79 if (ping_socket < 0) {
80 syslog(LOG_ERR, "Unable to open raw socket: %s", strerror(errno));
85 setsockopt(ping_socket, IPPROTO_RAW, IPV6_CHECKSUM, &val, sizeof(val));
87 // This is required by RFC 4861
89 setsockopt(ping_socket, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &val, sizeof(val));
90 setsockopt(ping_socket, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &val, sizeof(val));
92 // Filter all packages, we only want to send
93 struct icmp6_filter filt;
94 ICMP6_FILTER_SETBLOCKALL(&filt);
95 setsockopt(ping_socket, IPPROTO_ICMPV6, ICMP6_FILTER, &filt, sizeof(filt));
98 // Netlink socket, continued...
99 group = RTNLGRP_NEIGH;
100 setsockopt(rtnl_event.uloop.fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &group, sizeof(group));
106 static void dump_neigh_table(bool proxy)
112 {sizeof(req), RTM_GETNEIGH, NLM_F_REQUEST | NLM_F_DUMP,
114 {.ndm_family = AF_INET6, .ndm_flags = (proxy) ? NTF_PROXY : 0}
116 send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT);
117 odhcpd_process(&rtnl_event);
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 if (!enable || iface->ndp != RELAYD_RELAY)
134 if (write(procfd, "0\n", 2) < 0) {}
139 if (enable && (iface->ra == RELAYD_SERVER ||
140 iface->dhcpv6 == RELAYD_SERVER || iface->ndp == RELAYD_RELAY)) {
141 // Synthesize initial address events
144 struct ifaddrmsg ifa;
146 {sizeof(req2), RTM_GETADDR, NLM_F_REQUEST | NLM_F_DUMP,
148 {.ifa_family = AF_INET6, .ifa_index = iface->ifindex}
150 send(rtnl_event.uloop.fd, &req2, sizeof(req2), MSG_DONTWAIT);
153 if (enable && iface->ndp == RELAYD_RELAY) {
154 if (write(procfd, "1\n", 2) < 0) {}
157 int sock = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC, htons(ETH_P_IPV6));
159 syslog(LOG_ERR, "Unable to open packet socket: %s",
164 #ifdef PACKET_RECV_TYPE
165 int pktt = 1 << PACKET_MULTICAST;
166 setsockopt(sock, SOL_PACKET, PACKET_RECV_TYPE, &pktt, sizeof(pktt));
169 if (setsockopt(sock, SOL_SOCKET, SO_ATTACH_FILTER,
170 &bpf_prog, sizeof(bpf_prog))) {
171 syslog(LOG_ERR, "Failed to set BPF: %s", strerror(errno));
175 struct sockaddr_ll ll = {
176 .sll_family = AF_PACKET,
177 .sll_ifindex = iface->ifindex,
178 .sll_protocol = htons(ETH_P_IPV6),
184 bind(sock, (struct sockaddr*)&ll, sizeof(ll));
186 struct packet_mreq mreq = {iface->ifindex, PACKET_MR_ALLMULTI, ETH_ALEN, {0}};
187 setsockopt(sock, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq));
189 iface->ndp_event.uloop.fd = sock;
190 iface->ndp_event.handle_dgram = handle_solicit;
191 odhcpd_register(&iface->ndp_event);
193 // If we already were enabled dump is unnecessary, if not do dump
195 dump_neigh_table(false);
203 dump_neigh_table(true);
209 // Send an ICMP-ECHO. This is less for actually pinging but for the
210 // neighbor cache to be kept up-to-date.
211 static void ping6(struct in6_addr *addr,
212 const struct interface *iface)
214 struct sockaddr_in6 dest = {AF_INET6, 0, 0, *addr, iface->ifindex};
215 struct icmp6_hdr echo = {.icmp6_type = ICMP6_ECHO_REQUEST};
216 struct iovec iov = {&echo, sizeof(echo)};
218 odhcpd_setup_route(addr, 128, iface, NULL, 128, true);
219 odhcpd_send(ping_socket, &dest, &iov, 1, iface);
220 odhcpd_setup_route(addr, 128, iface, NULL, 128, false);
224 // Handle solicitations
225 static void handle_solicit(void *addr, void *data, size_t len,
226 struct interface *iface, _unused void *dest)
228 struct ip6_hdr *ip6 = data;
229 struct nd_neighbor_solicit *req = (struct nd_neighbor_solicit*)&ip6[1];
230 struct sockaddr_ll *ll = addr;
232 // Solicitation is for duplicate address detection
233 bool ns_is_dad = IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src);
235 // Don't forward any non-DAD solicitation for external ifaces
236 // TODO: check if we should even forward DADs for them
237 if (iface->external && !ns_is_dad)
240 if (len < sizeof(*ip6) + sizeof(*req))
241 return; // Invalid reqicitation
243 if (IN6_IS_ADDR_LINKLOCAL(&req->nd_ns_target) ||
244 IN6_IS_ADDR_LOOPBACK(&req->nd_ns_target) ||
245 IN6_IS_ADDR_MULTICAST(&req->nd_ns_target))
246 return; // Invalid target
248 char ipbuf[INET6_ADDRSTRLEN];
249 inet_ntop(AF_INET6, &req->nd_ns_target, ipbuf, sizeof(ipbuf));
250 syslog(LOG_DEBUG, "Got a NS for %s", ipbuf);
253 odhcpd_get_mac(iface, mac);
254 if (!memcmp(ll->sll_addr, mac, sizeof(mac)))
255 return; // Looped back
258 list_for_each_entry(c, &interfaces, head)
259 if (iface->ndp == RELAYD_RELAY && iface != c &&
260 (ns_is_dad || !c->external))
261 ping6(&req->nd_ns_target, c);
264 // Use rtnetlink to modify kernel routes
265 static void setup_route(struct in6_addr *addr, struct interface *iface, bool add)
267 char namebuf[INET6_ADDRSTRLEN];
268 inet_ntop(AF_INET6, addr, namebuf, sizeof(namebuf));
269 syslog(LOG_NOTICE, "%s about %s on %s",
270 (add) ? "Learned" : "Forgot", namebuf, iface->ifname);
272 if (iface->learn_routes)
273 odhcpd_setup_route(addr, 128, iface, NULL, 1024, add);
277 static int prefixcmp(const void *va, const void *vb)
279 const struct odhcpd_ipaddr *a = va, *b = vb;
280 uint32_t a_pref = ((a->addr.s6_addr[0] & 0xfe) != 0xfc) ? a->preferred : 1;
281 uint32_t b_pref = ((b->addr.s6_addr[0] & 0xfe) != 0xfc) ? b->preferred : 1;
282 return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
285 // Check address update
286 static void check_updates(struct interface *iface)
288 struct odhcpd_ipaddr addr[8] = {{IN6ADDR_ANY_INIT, 0, 0, 0, 0}};
289 time_t now = odhcpd_time();
290 ssize_t len = odhcpd_get_interface_addresses(iface->ifindex, addr, 8);
295 qsort(addr, len, sizeof(*addr), prefixcmp);
297 for (int i = 0; i < len; ++i) {
298 addr[i].addr.s6_addr32[3] = 0;
300 if (addr[i].preferred < UINT32_MAX - now)
301 addr[i].preferred += now;
303 if (addr[i].valid < UINT32_MAX - now)
304 addr[i].valid += now;
307 bool change = len != (ssize_t)iface->ia_addr_len;
308 for (ssize_t i = 0; !change && i < len; ++i)
309 if (!IN6_ARE_ADDR_EQUAL(&addr[i].addr, &iface->ia_addr[i].addr) ||
310 (addr[i].preferred > 0) != (iface->ia_addr[i].preferred > 0) ||
311 addr[i].valid < iface->ia_addr[i].valid ||
312 addr[i].preferred < iface->ia_addr[i].preferred)
316 dhcpv6_ia_preupdate(iface);
318 memcpy(iface->ia_addr, addr, len * sizeof(*addr));
319 iface->ia_addr_len = len;
322 dhcpv6_ia_postupdate(iface, now);
329 // Handler for neighbor cache entries from the kernel. This is our source
330 // to learn and unlearn hosts on interfaces.
331 static void handle_rtnetlink(_unused void *addr, void *data, size_t len,
332 _unused struct interface *iface, _unused void *dest)
334 bool dump_neigh = false;
335 struct in6_addr last_solicited = IN6ADDR_ANY_INIT;
337 for (struct nlmsghdr *nh = data; NLMSG_OK(nh, len);
338 nh = NLMSG_NEXT(nh, len)) {
339 struct ndmsg *ndm = NLMSG_DATA(nh);
340 struct rtmsg *rtm = NLMSG_DATA(nh);
342 bool is_addr = (nh->nlmsg_type == RTM_NEWADDR
343 || nh->nlmsg_type == RTM_DELADDR);
344 bool is_route = (nh->nlmsg_type == RTM_NEWROUTE
345 || nh->nlmsg_type == RTM_DELROUTE);
346 bool is_neigh = (nh->nlmsg_type == RTM_NEWNEIGH
347 || nh->nlmsg_type == RTM_DELNEIGH);
349 // Family and ifindex are on the same offset for NEIGH and ADDR
350 if ((!is_addr && !is_route && !is_neigh)
351 || NLMSG_PAYLOAD(nh, 0) < sizeof(*ndm)
352 || ndm->ndm_family != AF_INET6)
355 // Inform about a change in default route
356 if (is_route && rtm->rtm_dst_len == 0)
362 size_t rta_offset = (is_addr) ? sizeof(struct ifaddrmsg) : sizeof(*ndm);
363 uint16_t atype = (is_addr) ? IFA_ADDRESS : NDA_DST;
364 ssize_t alen = NLMSG_PAYLOAD(nh, rta_offset);
365 struct in6_addr *addr = NULL;
367 for (struct rtattr *rta = (void*)(((uint8_t*)ndm) + rta_offset);
368 RTA_OK(rta, alen); rta = RTA_NEXT(rta, alen)) {
369 if (rta->rta_type == atype &&
370 RTA_PAYLOAD(rta) >= sizeof(*addr)) {
371 addr = RTA_DATA(rta);
376 struct interface *iface = odhcpd_get_interface_by_index(ndm->ndm_ifindex);
380 // Address not specified or unrelated
381 if (!addr || IN6_IS_ADDR_LINKLOCAL(addr) ||
382 IN6_IS_ADDR_MULTICAST(addr))
388 add = (nh->nlmsg_type == RTM_NEWADDR);
390 add = (nh->nlmsg_type == RTM_NEWNEIGH && (ndm->ndm_state &
391 (NUD_REACHABLE | NUD_STALE | NUD_DELAY | NUD_PROBE
392 | NUD_PERMANENT | NUD_NOARP)));
394 if (iface->ndp == RELAYD_RELAY) {
395 // Replay change to all neighbor cache
399 struct nlattr nla_dst;
402 {sizeof(req), RTM_DELNEIGH, NLM_F_REQUEST,
404 {.ndm_family = AF_INET6, .ndm_flags = NTF_PROXY},
405 {sizeof(struct nlattr) + sizeof(struct in6_addr), NDA_DST},
409 if (ndm->ndm_flags & NTF_PROXY) {
410 // Dump & flush proxy entries
411 if (nh->nlmsg_type == RTM_NEWNEIGH) {
412 req.ndm.ndm_ifindex = iface->ifindex;
413 send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT);
414 setup_route(addr, iface, false);
419 list_for_each_entry(c, &interfaces, head) {
423 if (c->ndp == RELAYD_RELAY) {
424 req.nh.nlmsg_type = RTM_NEWNEIGH;
425 req.nh.nlmsg_flags |= NLM_F_CREATE | NLM_F_REPLACE;
427 req.ndm.ndm_ifindex = c->ifindex;
428 send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT);
429 } else { // Delete NDP cache from interfaces without relay
430 req.nh.nlmsg_type = RTM_DELNEIGH;
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);
438 setup_route(addr, iface, true);
440 if (nh->nlmsg_type == RTM_NEWNEIGH) {
441 // might be locally originating
442 if (!IN6_ARE_ADDR_EQUAL(&last_solicited, addr)) {
443 last_solicited = *addr;
446 list_for_each_entry(c, &interfaces, head)
447 if (iface->ndp == RELAYD_RELAY && iface != c &&
448 !c->external == false)
453 list_for_each_entry(c, &interfaces, head) {
454 if (c->ndp == RELAYD_RELAY && iface != c) {
455 req.ndm.ndm_ifindex = c->ifindex;
456 send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT);
459 setup_route(addr, iface, false);
461 // also: dump to add proxies back in case it moved elsewhere
468 check_updates(iface);
470 if (iface->dhcpv6 == RELAYD_SERVER)
471 iface->ia_reconf = true;
473 if (iface->ndp == RELAYD_RELAY && iface->master) {
474 // Replay address changes on all slave interfaces
475 nh->nlmsg_flags = NLM_F_REQUEST;
477 if (nh->nlmsg_type == RTM_NEWADDR)
478 nh->nlmsg_flags |= NLM_F_CREATE | NLM_F_REPLACE;
481 list_for_each_entry(c, &interfaces, head) {
482 if (c->ndp == RELAYD_RELAY && !c->master) {
483 ndm->ndm_ifindex = c->ifindex;
484 send(rtnl_event.uloop.fd, nh, nh->nlmsg_len, MSG_DONTWAIT);
492 dump_neigh_table(false);