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;
46 static void handle_solicit(void *addr, void *data, size_t len,
47 struct interface *iface, void *dest);
48 static void handle_rtnl_event(struct odhcpd_event *ev);
49 static int cb_rtnl_valid(struct nl_msg *msg, void *arg);
50 static void catch_rtnl_err(struct odhcpd_event *e, int error);
52 static int addr6_dump_rqs = 0;
53 static int ping_socket = -1;
54 static struct event_socket rtnl_event = {
56 .uloop = {.fd = - 1, },
58 .handle_error = catch_rtnl_err,
59 .recv_msgs = handle_rtnl_event,
62 .sock_bufsize = 133120,
65 // Filter ICMPv6 messages of type neighbor soliciation
66 static struct sock_filter bpf[] = {
67 BPF_STMT(BPF_LD | BPF_B | BPF_ABS, offsetof(struct ip6_hdr, ip6_nxt)),
68 BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, IPPROTO_ICMPV6, 0, 3),
69 BPF_STMT(BPF_LD | BPF_B | BPF_ABS, sizeof(struct ip6_hdr) +
70 offsetof(struct icmp6_hdr, icmp6_type)),
71 BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, ND_NEIGHBOR_SOLICIT, 0, 1),
72 BPF_STMT(BPF_RET | BPF_K, 0xffffffff),
73 BPF_STMT(BPF_RET | BPF_K, 0),
75 static const struct sock_fprog bpf_prog = {sizeof(bpf) / sizeof(*bpf), bpf};
78 // Initialize NDP-proxy
83 rtnl_event.sock = odhcpd_create_nl_socket(NETLINK_ROUTE);
87 rtnl_event.ev.uloop.fd = nl_socket_get_fd(rtnl_event.sock);
89 if (nl_socket_set_buffer_size(rtnl_event.sock, rtnl_event.sock_bufsize, 0))
92 nl_socket_disable_seq_check(rtnl_event.sock);
94 nl_socket_modify_cb(rtnl_event.sock, NL_CB_VALID, NL_CB_CUSTOM,
97 // Receive IPv6 address, IPv6 routes and neighbor events
98 if (nl_socket_add_memberships(rtnl_event.sock, RTNLGRP_IPV6_IFADDR,
99 RTNLGRP_IPV6_ROUTE, RTNLGRP_NEIGH, 0))
102 odhcpd_register(&rtnl_event.ev);
104 // Open ICMPv6 socket
105 ping_socket = socket(AF_INET6, SOCK_RAW | SOCK_CLOEXEC, IPPROTO_ICMPV6);
106 if (ping_socket < 0) {
107 syslog(LOG_ERR, "Unable to open raw socket: %s", strerror(errno));
111 setsockopt(ping_socket, IPPROTO_RAW, IPV6_CHECKSUM, &val, sizeof(val));
113 // This is required by RFC 4861
115 setsockopt(ping_socket, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &val, sizeof(val));
116 setsockopt(ping_socket, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &val, sizeof(val));
118 // Filter all packages, we only want to send
119 struct icmp6_filter filt;
120 ICMP6_FILTER_SETBLOCKALL(&filt);
121 setsockopt(ping_socket, IPPROTO_ICMPV6, ICMP6_FILTER, &filt, sizeof(filt));
126 if (rtnl_event.sock) {
127 nl_socket_free(rtnl_event.sock);
128 rtnl_event.sock = NULL;
129 rtnl_event.ev.uloop.fd = -1;
135 static void dump_neigh_table(const bool proxy)
139 .ndm_family = AF_INET6,
140 .ndm_flags = proxy ? NTF_PROXY : 0,
143 msg = nlmsg_alloc_simple(RTM_GETNEIGH, NLM_F_REQUEST | NLM_F_DUMP);
147 nlmsg_append(msg, &ndm, sizeof(ndm), 0);
149 nl_send_auto_complete(rtnl_event.sock, msg);
154 static void dump_addr6_table(void)
157 struct ifaddrmsg ifa = {
158 .ifa_family = AF_INET6,
161 msg = nlmsg_alloc_simple(RTM_GETADDR, NLM_F_REQUEST | NLM_F_DUMP);
165 nlmsg_append(msg, &ifa, sizeof(ifa), 0);
167 nl_send_auto_complete(rtnl_event.sock, msg);
172 void ndp_handle_addr6_dump(void)
181 inline void ndp_rqs_addr6_dump(void)
186 int setup_ndp_interface(struct interface *iface, bool enable)
189 bool dump_neigh = false;
192 snprintf(procbuf, sizeof(procbuf), "/proc/sys/net/ipv6/conf/%s/proxy_ndp", iface->ifname);
193 procfd = open(procbuf, O_WRONLY);
200 if (iface->ndp_event.uloop.fd > 0) {
201 uloop_fd_delete(&iface->ndp_event.uloop);
202 close(iface->ndp_event.uloop.fd);
203 iface->ndp_event.uloop.fd = -1;
205 if (!enable || iface->ndp != RELAYD_RELAY)
206 if (write(procfd, "0\n", 2) < 0) {}
211 if (enable && iface->ndp == RELAYD_RELAY) {
212 if (write(procfd, "1\n", 2) < 0) {}
214 int sock = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC, htons(ETH_P_IPV6));
216 syslog(LOG_ERR, "Unable to open packet socket: %s",
222 #ifdef PACKET_RECV_TYPE
223 int pktt = 1 << PACKET_MULTICAST;
224 setsockopt(sock, SOL_PACKET, PACKET_RECV_TYPE, &pktt, sizeof(pktt));
227 if (setsockopt(sock, SOL_SOCKET, SO_ATTACH_FILTER,
228 &bpf_prog, sizeof(bpf_prog))) {
229 syslog(LOG_ERR, "Failed to set BPF: %s", strerror(errno));
234 struct sockaddr_ll ll = {
235 .sll_family = AF_PACKET,
236 .sll_ifindex = iface->ifindex,
237 .sll_protocol = htons(ETH_P_IPV6),
243 bind(sock, (struct sockaddr*)&ll, sizeof(ll));
245 struct packet_mreq mreq = {iface->ifindex, PACKET_MR_ALLMULTI, ETH_ALEN, {0}};
246 setsockopt(sock, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq));
248 iface->ndp_event.uloop.fd = sock;
249 iface->ndp_event.handle_dgram = handle_solicit;
250 odhcpd_register(&iface->ndp_event);
252 // If we already were enabled dump is unnecessary, if not do dump
254 dump_neigh_table(false);
258 ndp_rqs_addr6_dump();
262 dump_neigh_table(true);
272 // Send an ICMP-ECHO. This is less for actually pinging but for the
273 // neighbor cache to be kept up-to-date.
274 static void ping6(struct in6_addr *addr,
275 const struct interface *iface)
277 struct sockaddr_in6 dest = { .sin6_family = AF_INET6, .sin6_addr = *addr, .sin6_scope_id = iface->ifindex, };
278 struct icmp6_hdr echo = { .icmp6_type = ICMP6_ECHO_REQUEST };
279 struct iovec iov = { .iov_base = &echo, .iov_len = sizeof(echo) };
280 char ipbuf[INET6_ADDRSTRLEN];
282 inet_ntop(AF_INET6, addr, ipbuf, sizeof(ipbuf));
283 syslog(LOG_NOTICE, "Pinging for %s%%%s", ipbuf, iface->ifname);
285 odhcpd_setup_route(addr, 128, iface, NULL, 128, true);
286 odhcpd_send(ping_socket, &dest, &iov, 1, iface);
287 odhcpd_setup_route(addr, 128, iface, NULL, 128, false);
290 // Handle solicitations
291 static void handle_solicit(void *addr, void *data, size_t len,
292 struct interface *iface, _unused void *dest)
294 struct ip6_hdr *ip6 = data;
295 struct nd_neighbor_solicit *req = (struct nd_neighbor_solicit*)&ip6[1];
296 struct sockaddr_ll *ll = addr;
297 char ipbuf[INET6_ADDRSTRLEN];
300 // Solicitation is for duplicate address detection
301 bool ns_is_dad = IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src);
303 // Don't process solicit messages on non relay interfaces
304 // Don't forward any non-DAD solicitation for external ifaces
305 // TODO: check if we should even forward DADs for them
306 if (iface->ndp != RELAYD_RELAY || (iface->external && !ns_is_dad))
309 if (len < sizeof(*ip6) + sizeof(*req))
310 return; // Invalid reqicitation
312 if (IN6_IS_ADDR_LINKLOCAL(&req->nd_ns_target) ||
313 IN6_IS_ADDR_LOOPBACK(&req->nd_ns_target) ||
314 IN6_IS_ADDR_MULTICAST(&req->nd_ns_target))
315 return; // Invalid target
317 inet_ntop(AF_INET6, &req->nd_ns_target, ipbuf, sizeof(ipbuf));
318 syslog(LOG_DEBUG, "Got a NS for %s%%%s", ipbuf, iface->ifname);
320 odhcpd_get_mac(iface, mac);
321 if (!memcmp(ll->sll_addr, mac, sizeof(mac)))
322 return; // Looped back
325 list_for_each_entry(c, &interfaces, head)
326 if (iface != c && c->ndp == RELAYD_RELAY &&
327 (ns_is_dad || !c->external))
328 ping6(&req->nd_ns_target, c);
331 // Use rtnetlink to modify kernel routes
332 static void setup_route(struct in6_addr *addr, struct interface *iface, bool add)
334 char ipbuf[INET6_ADDRSTRLEN];
336 inet_ntop(AF_INET6, addr, ipbuf, sizeof(ipbuf));
337 syslog(LOG_NOTICE, "%s about %s%%%s",
338 (add) ? "Learned" : "Forgot", ipbuf, iface->ifname);
340 if (iface->learn_routes)
341 odhcpd_setup_route(addr, 128, iface, NULL, 1024, add);
345 static int prefixcmp(const void *va, const void *vb)
347 const struct odhcpd_ipaddr *a = va, *b = vb;
348 uint32_t a_pref = IN6_IS_ADDR_ULA(&a->addr) ? 1 : a->preferred;
349 uint32_t b_pref = IN6_IS_ADDR_ULA(&b->addr) ? 1 : b->preferred;
350 return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
353 // Check address update
354 static void check_addr_updates(struct interface *iface)
356 struct odhcpd_ipaddr addr[RELAYD_MAX_ADDRS] = {{IN6ADDR_ANY_INIT, 0, 0, 0, 0}};
357 time_t now = odhcpd_time();
358 ssize_t len = odhcpd_get_interface_addresses(iface->ifindex, addr, ARRAY_SIZE(addr));
363 qsort(addr, len, sizeof(*addr), prefixcmp);
365 for (int i = 0; i < len; ++i) {
366 addr[i].addr.s6_addr32[3] = 0;
368 if (addr[i].preferred < UINT32_MAX - now)
369 addr[i].preferred += now;
371 if (addr[i].valid < UINT32_MAX - now)
372 addr[i].valid += now;
375 bool change = len != (ssize_t)iface->ia_addr_len;
376 for (ssize_t i = 0; !change && i < len; ++i)
377 if (!IN6_ARE_ADDR_EQUAL(&addr[i].addr, &iface->ia_addr[i].addr) ||
378 (addr[i].preferred > 0) != (iface->ia_addr[i].preferred > 0) ||
379 addr[i].valid < iface->ia_addr[i].valid ||
380 addr[i].preferred < iface->ia_addr[i].preferred)
384 dhcpv6_ia_preupdate(iface);
386 memcpy(iface->ia_addr, addr, len * sizeof(*addr));
387 iface->ia_addr_len = len;
390 dhcpv6_ia_postupdate(iface, now);
393 syslog(LOG_INFO, "Raising SIGUSR1 due to address change on %s", iface->ifname);
398 void setup_addr_for_relaying(struct in6_addr *addr, struct interface *iface, bool add)
401 char ipbuf[INET6_ADDRSTRLEN];
403 inet_ntop(AF_INET6, addr, ipbuf, sizeof(ipbuf));
405 list_for_each_entry(c, &interfaces, head) {
406 if (iface == c || (c->ndp != RELAYD_RELAY && !add))
409 add = (c->ndp == RELAYD_RELAY ? add : false);
411 if (odhcpd_setup_proxy_neigh(addr, c, add))
412 syslog(LOG_DEBUG, "Failed to %s proxy neighbour entry %s%%%s",
413 add ? "add" : "delete", ipbuf, iface->ifname);
415 syslog(LOG_DEBUG, "%s proxy neighbour entry %s%%%s",
416 add ? "Added" : "Deleted", ipbuf, iface->ifname);
420 void setup_ping6(struct in6_addr *addr, struct interface *iface)
424 list_for_each_entry(c, &interfaces, head) {
425 if (iface == c || c->ndp != RELAYD_RELAY ||
433 static struct in6_addr last_solicited;
435 static void handle_rtnl_event(struct odhcpd_event *e)
437 struct event_socket *ev_sock = container_of(e, struct event_socket, ev);
439 nl_recvmsgs_default(ev_sock->sock);
443 // Handler for neighbor cache entries from the kernel. This is our source
444 // to learn and unlearn hosts on interfaces.
445 static int cb_rtnl_valid(struct nl_msg *msg, _unused void *arg)
447 struct nlmsghdr *hdr = nlmsg_hdr(msg);
448 struct in6_addr *addr = NULL;
449 struct interface *iface = NULL;
451 char ipbuf[INET6_ADDRSTRLEN];
453 switch (hdr->nlmsg_type) {
456 struct rtmsg *rtm = nlmsg_data(hdr);
458 if (!nlmsg_valid_hdr(hdr, sizeof(*rtm)) ||
459 rtm->rtm_family != AF_INET6)
462 if (rtm->rtm_dst_len == 0) {
463 syslog(LOG_INFO, "Raising SIGUSR1 due to default route change");
472 struct ifaddrmsg *ifa = nlmsg_data(hdr);
473 struct nlattr *nla[__IFA_MAX];
475 if (!nlmsg_valid_hdr(hdr, sizeof(*ifa)) ||
476 ifa->ifa_family != AF_INET6)
479 iface = odhcpd_get_interface_by_index(ifa->ifa_index);
483 nlmsg_parse(hdr, sizeof(*ifa), nla, __IFA_MAX - 1, NULL);
484 if (!nla[IFA_ADDRESS])
487 addr = nla_data(nla[IFA_ADDRESS]);
488 if (!addr || IN6_IS_ADDR_LINKLOCAL(addr) ||
489 IN6_IS_ADDR_MULTICAST(addr))
492 inet_ntop(AF_INET6, addr, ipbuf, sizeof(ipbuf));
493 syslog(LOG_DEBUG, "Netlink %s %s%%%s", true ? "newaddr" : "deladdr",
494 ipbuf, iface->ifname);
496 check_addr_updates(iface);
498 if (iface->ndp != RELAYD_RELAY)
501 /* handle the relay logic below */
502 setup_addr_for_relaying(addr, iface, add);
505 dump_neigh_table(false);
512 struct ndmsg *ndm = nlmsg_data(hdr);
513 struct nlattr *nla[__NDA_MAX];
515 if (!nlmsg_valid_hdr(hdr, sizeof(*ndm)) ||
516 ndm->ndm_family != AF_INET6)
519 iface = odhcpd_get_interface_by_index(ndm->ndm_ifindex);
520 if (!iface || iface->ndp != RELAYD_RELAY)
521 return (iface ? NL_OK : NL_SKIP);
523 nlmsg_parse(hdr, sizeof(*ndm), nla, __NDA_MAX - 1, NULL);
527 addr = nla_data(nla[NDA_DST]);
528 if (!addr || IN6_IS_ADDR_LINKLOCAL(addr) ||
529 IN6_IS_ADDR_MULTICAST(addr))
532 inet_ntop(AF_INET6, addr, ipbuf, sizeof(ipbuf));
533 syslog(LOG_DEBUG, "Netlink %s %s%%%s", true ? "newneigh" : "delneigh",
534 ipbuf, iface->ifname);
536 if (ndm->ndm_flags & NTF_PROXY) {
537 /* Dump and flush proxy entries */
538 if (hdr->nlmsg_type == RTM_NEWNEIGH) {
539 odhcpd_setup_proxy_neigh(addr, iface, false);
540 setup_route(addr, iface, false);
541 dump_neigh_table(false);
547 if (add && !(ndm->ndm_state &
548 (NUD_REACHABLE | NUD_STALE | NUD_DELAY | NUD_PROBE |
549 NUD_PERMANENT | NUD_NOARP))) {
550 if (!IN6_ARE_ADDR_EQUAL(&last_solicited, addr)) {
551 last_solicited = *addr;
552 setup_ping6(addr, iface);
558 setup_addr_for_relaying(addr, iface, add);
559 setup_route(addr, iface, add);
562 dump_neigh_table(false);
573 static void catch_rtnl_err(struct odhcpd_event *e, int error)
575 struct event_socket *ev_sock = container_of(e, struct event_socket, ev);
577 if (error != ENOBUFS)
580 /* Double netlink event buffer size */
581 ev_sock->sock_bufsize *= 2;
583 if (nl_socket_set_buffer_size(ev_sock->sock, ev_sock->sock_bufsize, 0))
590 odhcpd_deregister(e);