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);
118 odhcpd_process(&rtnl_event);
122 int setup_ndp_interface(struct interface *iface, bool enable)
125 snprintf(procbuf, sizeof(procbuf), "/proc/sys/net/ipv6/conf/%s/proxy_ndp", iface->ifname);
126 int procfd = open(procbuf, O_WRONLY);
127 bool dump_neigh = false;
129 if (iface->ndp_event.uloop.fd > 0) {
130 uloop_fd_delete(&iface->ndp_event.uloop);
131 close(iface->ndp_event.uloop.fd);
132 iface->ndp_event.uloop.fd = -1;
134 if (!enable || iface->ndp != RELAYD_RELAY)
135 if (write(procfd, "0\n", 2) < 0) {}
140 if (enable && (iface->ra == RELAYD_SERVER ||
141 iface->dhcpv6 == RELAYD_SERVER || iface->ndp == RELAYD_RELAY)) {
142 // Synthesize initial address events
145 struct ifaddrmsg ifa;
147 {sizeof(req2), RTM_GETADDR, NLM_F_REQUEST | NLM_F_DUMP,
149 {.ifa_family = AF_INET6, .ifa_index = iface->ifindex}
151 send(rtnl_event.uloop.fd, &req2, sizeof(req2), MSG_DONTWAIT);
154 if (enable && iface->ndp == RELAYD_RELAY) {
155 if (write(procfd, "1\n", 2) < 0) {}
158 int sock = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC, htons(ETH_P_IPV6));
160 syslog(LOG_ERR, "Unable to open packet socket: %s",
165 #ifdef PACKET_RECV_TYPE
166 int pktt = 1 << PACKET_MULTICAST;
167 setsockopt(sock, SOL_PACKET, PACKET_RECV_TYPE, &pktt, sizeof(pktt));
170 if (setsockopt(sock, SOL_SOCKET, SO_ATTACH_FILTER,
171 &bpf_prog, sizeof(bpf_prog))) {
172 syslog(LOG_ERR, "Failed to set BPF: %s", strerror(errno));
176 struct sockaddr_ll ll = {
177 .sll_family = AF_PACKET,
178 .sll_ifindex = iface->ifindex,
179 .sll_protocol = htons(ETH_P_IPV6),
185 bind(sock, (struct sockaddr*)&ll, sizeof(ll));
187 struct packet_mreq mreq = {iface->ifindex, PACKET_MR_ALLMULTI, ETH_ALEN, {0}};
188 setsockopt(sock, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq));
190 iface->ndp_event.uloop.fd = sock;
191 iface->ndp_event.handle_dgram = handle_solicit;
192 odhcpd_register(&iface->ndp_event);
194 // If we already were enabled dump is unnecessary, if not do dump
196 dump_neigh_table(false);
204 dump_neigh_table(true);
210 // Send an ICMP-ECHO. This is less for actually pinging but for the
211 // neighbor cache to be kept up-to-date.
212 static ssize_t ping6(struct in6_addr *addr,
213 const struct interface *iface)
215 struct sockaddr_in6 dest = {AF_INET6, 0, 0, *addr, iface->ifindex};
216 struct icmp6_hdr echo = {.icmp6_type = ICMP6_ECHO_REQUEST};
217 struct iovec iov = {&echo, sizeof(echo)};
218 return odhcpd_send(ping_socket, &dest, &iov, 1, iface);
222 // Handle solicitations
223 static void handle_solicit(void *addr, void *data, size_t len,
224 struct interface *iface, _unused void *dest)
226 struct ip6_hdr *ip6 = data;
227 struct nd_neighbor_solicit *req = (struct nd_neighbor_solicit*)&ip6[1];
228 struct sockaddr_ll *ll = addr;
230 // Solicitation is for duplicate address detection
231 bool ns_is_dad = IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src);
233 // Don't forward any non-DAD solicitation for external ifaces
234 // TODO: check if we should even forward DADs for them
235 if (iface->external && !ns_is_dad)
238 if (len < sizeof(*ip6) + sizeof(*req))
239 return; // Invalid reqicitation
241 if (IN6_IS_ADDR_LINKLOCAL(&req->nd_ns_target) ||
242 IN6_IS_ADDR_LOOPBACK(&req->nd_ns_target) ||
243 IN6_IS_ADDR_MULTICAST(&req->nd_ns_target))
244 return; // Invalid target
246 char ipbuf[INET6_ADDRSTRLEN];
247 inet_ntop(AF_INET6, &req->nd_ns_target, ipbuf, sizeof(ipbuf));
248 syslog(LOG_DEBUG, "Got a NS for %s", ipbuf);
251 odhcpd_get_mac(iface, mac);
252 if (!memcmp(ll->sll_addr, mac, sizeof(mac)))
253 return; // Looped back
256 list_for_each_entry(c, &interfaces, head)
257 if (iface->ndp == RELAYD_RELAY && iface != c &&
258 (ns_is_dad || !c->external))
259 ping6(&req->nd_ns_target, c);
263 void odhcpd_setup_route(const struct in6_addr *addr, int prefixlen,
264 const struct interface *iface, const struct in6_addr *gw, bool add)
269 struct rtattr rta_dst;
270 struct in6_addr dst_addr;
271 struct rtattr rta_oif;
273 struct rtattr rta_table;
275 struct rtattr rta_gw;
278 {sizeof(req), 0, NLM_F_REQUEST, ++rtnl_seqid, 0},
279 {AF_INET6, prefixlen, 0, 0, 0, 0, 0, 0, 0},
280 {sizeof(struct rtattr) + sizeof(struct in6_addr), RTA_DST},
282 {sizeof(struct rtattr) + sizeof(uint32_t), RTA_OIF},
284 {sizeof(struct rtattr) + sizeof(uint32_t), RTA_TABLE},
286 {sizeof(struct rtattr) + sizeof(struct in6_addr), RTA_GATEWAY},
294 req.nh.nlmsg_type = RTM_NEWROUTE;
295 req.nh.nlmsg_flags |= (NLM_F_CREATE | NLM_F_REPLACE);
296 req.rtm.rtm_protocol = RTPROT_STATIC;
297 req.rtm.rtm_scope = (gw) ? RT_SCOPE_UNIVERSE : RT_SCOPE_LINK;
298 req.rtm.rtm_type = RTN_UNICAST;
300 req.nh.nlmsg_type = RTM_DELROUTE;
301 req.rtm.rtm_scope = RT_SCOPE_NOWHERE;
304 req.nh.nlmsg_len = (gw) ? sizeof(req) : offsetof(struct req, rta_gw);
305 send(rtnl_event.uloop.fd, &req, req.nh.nlmsg_len, MSG_DONTWAIT);
308 // Use rtnetlink to modify kernel routes
309 static void setup_route(struct in6_addr *addr, struct interface *iface, bool add)
311 char namebuf[INET6_ADDRSTRLEN];
312 inet_ntop(AF_INET6, addr, namebuf, sizeof(namebuf));
313 syslog(LOG_NOTICE, "%s about %s on %s",
314 (add) ? "Learned" : "Forgot", namebuf, iface->ifname);
316 if (iface->learn_routes)
317 odhcpd_setup_route(addr, 128, iface, NULL, add);
321 // Handler for neighbor cache entries from the kernel. This is our source
322 // to learn and unlearn hosts on interfaces.
323 static void handle_rtnetlink(_unused void *addr, void *data, size_t len,
324 _unused struct interface *iface, _unused void *dest)
326 bool dump_neigh = false;
327 struct in6_addr last_solicited = IN6ADDR_ANY_INIT;
329 for (struct nlmsghdr *nh = data; NLMSG_OK(nh, len);
330 nh = NLMSG_NEXT(nh, len)) {
331 struct ndmsg *ndm = NLMSG_DATA(nh);
332 struct rtmsg *rtm = NLMSG_DATA(nh);
334 bool is_addr = (nh->nlmsg_type == RTM_NEWADDR
335 || nh->nlmsg_type == RTM_DELADDR);
336 bool is_route = (nh->nlmsg_type == RTM_NEWROUTE
337 || nh->nlmsg_type == RTM_DELROUTE);
338 bool is_neigh = (nh->nlmsg_type == RTM_NEWNEIGH
339 || nh->nlmsg_type == RTM_DELNEIGH);
341 // Family and ifindex are on the same offset for NEIGH and ADDR
342 if ((!is_addr && !is_route && !is_neigh)
343 || NLMSG_PAYLOAD(nh, 0) < sizeof(*ndm)
344 || ndm->ndm_family != AF_INET6)
347 // Inform about a change in default route
348 if (is_route && rtm->rtm_dst_len == 0)
350 else if (is_route && rtm->rtm_dst_len == 128)
354 size_t rta_offset = (is_route) ? sizeof(*rtm) : (is_addr) ?
355 sizeof(struct ifaddrmsg) : sizeof(*ndm);
356 uint16_t atype = (is_route) ? RTA_DST : (is_addr) ? IFA_ADDRESS : NDA_DST;
357 ssize_t alen = NLMSG_PAYLOAD(nh, rta_offset);
358 struct in6_addr *addr = NULL;
359 int *ifindex = (!is_route) ? &ndm->ndm_ifindex : NULL;
362 for (struct rtattr *rta = (void*)(((uint8_t*)ndm) + rta_offset);
363 RTA_OK(rta, alen); rta = RTA_NEXT(rta, alen)) {
364 if (rta->rta_type == atype &&
365 RTA_PAYLOAD(rta) >= sizeof(*addr)) {
366 addr = RTA_DATA(rta);
367 } else if (is_route && rta->rta_type == RTA_OIF &&
368 RTA_PAYLOAD(rta) == sizeof(int)) {
369 ifindex = (int*)RTA_DATA(rta);
370 } else if (is_route && rta->rta_type == RTA_GATEWAY) {
373 } else if (is_route && rta->rta_type == RTA_PRIORITY) {
374 metric = (int*)RTA_DATA(rta);
379 struct interface *iface = ifindex ? odhcpd_get_interface_by_index(*ifindex) : NULL;
383 // Keep-alive neighbor entries for RA sending
384 if (nh->nlmsg_type == RTM_DELNEIGH && !(ndm->ndm_state & NUD_FAILED) &&
385 addr && IN6_IS_ADDR_LINKLOCAL(addr) && iface->ra == RELAYD_SERVER)
388 // Address not specified or unrelated
389 if (!addr || IN6_IS_ADDR_LINKLOCAL(addr) ||
390 IN6_IS_ADDR_MULTICAST(addr))
396 add = (nh->nlmsg_type == RTM_NEWADDR);
398 add = (nh->nlmsg_type == RTM_NEWNEIGH && (ndm->ndm_state &
399 (NUD_REACHABLE | NUD_STALE | NUD_DELAY | NUD_PROBE
400 | NUD_PERMANENT | NUD_NOARP)));
402 if (iface->ndp == RELAYD_RELAY && !is_route) {
403 // Replay change to all neighbor cache
407 struct nlattr nla_dst;
410 {sizeof(req), RTM_DELNEIGH, NLM_F_REQUEST,
412 {.ndm_family = AF_INET6, .ndm_flags = NTF_PROXY},
413 {sizeof(struct nlattr) + sizeof(struct in6_addr), NDA_DST},
417 if (ndm->ndm_flags & NTF_PROXY) {
418 // Dump & flush proxy entries
419 if (nh->nlmsg_type == RTM_NEWNEIGH) {
420 req.ndm.ndm_ifindex = iface->ifindex;
421 send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT);
422 setup_route(addr, iface, false);
427 list_for_each_entry(c, &interfaces, head) {
431 if (c->ndp == RELAYD_RELAY) {
432 req.nh.nlmsg_type = RTM_NEWNEIGH;
433 req.nh.nlmsg_flags |= NLM_F_CREATE | NLM_F_REPLACE;
435 req.ndm.ndm_ifindex = c->ifindex;
436 send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT);
437 } else { // Delete NDP cache from interfaces without relay
438 req.nh.nlmsg_type = RTM_DELNEIGH;
439 req.nh.nlmsg_flags &= ~(NLM_F_CREATE | NLM_F_REPLACE);
441 req.ndm.ndm_ifindex = c->ifindex;
442 send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT);
446 setup_route(addr, iface, true);
448 if (nh->nlmsg_type == RTM_NEWNEIGH) {
449 // might be locally originating
450 if (!IN6_ARE_ADDR_EQUAL(&last_solicited, addr)) {
451 last_solicited = *addr;
454 list_for_each_entry(c, &interfaces, head)
455 if (iface->ndp == RELAYD_RELAY && iface != c &&
456 !c->external == false)
461 list_for_each_entry(c, &interfaces, head) {
462 if (c->ndp == RELAYD_RELAY && iface != c) {
463 req.ndm.ndm_ifindex = c->ifindex;
464 send(rtnl_event.uloop.fd, &req, sizeof(req), MSG_DONTWAIT);
467 setup_route(addr, iface, false);
469 // also: dump to add proxies back in case it moved elsewhere
476 if (iface->ra == RELAYD_SERVER)
477 raise(SIGUSR1); // Inform about a change in addresses
479 if (iface->dhcpv6 == RELAYD_SERVER)
480 iface->ia_reconf = true;
481 } else if (is_route) {
482 if (iface->ndp == RELAYD_RELAY && iface->master) {
483 // Replay on-link route changes on all slave interfaces
484 nh->nlmsg_flags = NLM_F_REQUEST;
486 if (nh->nlmsg_type == RTM_NEWROUTE)
487 nh->nlmsg_flags |= NLM_F_CREATE | NLM_F_REPLACE;
490 list_for_each_entry(c, &interfaces, head) {
491 if (c->ndp == RELAYD_RELAY && !c->master) {
492 *ifindex = c->ifindex;
493 *metric = (*metric & 0xffff) | (c->ifindex << 16);
494 send(rtnl_event.uloop.fd, nh, nh->nlmsg_len, MSG_DONTWAIT);
502 dump_neigh_table(false);