2 * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
3 * Copyright (C) 2017-2018 Hans Dedecker <dedeckeh@gmail.com>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License v2 as published by
7 * the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
29 #include <arpa/inet.h>
30 #include <sys/socket.h>
31 #include <sys/types.h>
32 #include <netinet/in.h>
33 #include <netinet/icmp6.h>
35 #include <linux/rtnetlink.h>
38 #define SOL_NETLINK 270
41 #ifndef NETLINK_ADD_MEMBERSHIP
42 #define NETLINK_ADD_MEMBERSHIP 1
46 #define IFF_LOWER_UP 0x10000
52 static bool nocarrier = false;
54 static int sock = -1, rtnl = -1;
55 static int if_index = 0;
56 static char if_name[IF_NAMESIZE] = {0};
57 static volatile int rs_attempt = 0;
58 static struct in6_addr lladdr = IN6ADDR_ANY_INIT;
59 static unsigned int ra_options = 0;
60 static unsigned int ra_holdoff_interval = 0;
61 static int ra_hoplimit = 0;
62 static int ra_mtu = 0;
63 static int ra_reachable = 0;
64 static int ra_retransmit = 0;
68 struct icmpv6_opt lladdr;
70 .hdr = {ND_ROUTER_SOLICIT, 0, 0, {{0}}},
71 .lladdr = {ND_OPT_SOURCE_LINKADDR, 1, {0}},
74 static void ra_send_rs(int signal __attribute__((unused)));
76 int ra_init(const char *ifname, const struct in6_addr *ifid,
77 unsigned int options, unsigned int holdoff_interval)
80 ra_holdoff_interval = holdoff_interval;
82 const pid_t ourpid = getpid();
83 sock = socket(AF_INET6, SOCK_RAW | SOCK_CLOEXEC, IPPROTO_ICMPV6);
87 if_index = if_nametoindex(ifname);
91 strncpy(if_name, ifname, sizeof(if_name) - 1);
94 rtnl = socket(AF_NETLINK, SOCK_DGRAM | SOCK_CLOEXEC, NETLINK_ROUTE);
98 struct sockaddr_nl rtnl_kernel = { .nl_family = AF_NETLINK };
99 if (connect(rtnl, (const struct sockaddr*)&rtnl_kernel, sizeof(rtnl_kernel)) < 0)
102 int val = RTNLGRP_LINK;
103 if (setsockopt(rtnl, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &val, sizeof(val)) < 0)
106 if (fcntl(rtnl, F_SETOWN, ourpid) < 0)
109 if (fcntl(rtnl, F_SETFL, fcntl(sock, F_GETFL) | O_ASYNC) < 0)
114 struct ifinfomsg ifi;
116 .hdr = {sizeof(req), RTM_GETLINK, NLM_F_REQUEST, 1, 0},
117 .ifi = {.ifi_index = if_index}
119 if (send(rtnl, &req, sizeof(req), 0) < 0)
124 // Filter ICMPv6 package types
125 struct icmp6_filter filt;
126 ICMP6_FILTER_SETBLOCKALL(&filt);
127 ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filt);
128 if (setsockopt(sock, IPPROTO_ICMPV6, ICMP6_FILTER, &filt, sizeof(filt)) < 0)
132 struct ipv6_mreq an = {ALL_IPV6_NODES, if_index};
133 if (setsockopt(sock, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, &an, sizeof(an)) < 0)
136 // Let the kernel compute our checksums
138 if (setsockopt(sock, IPPROTO_RAW, IPV6_CHECKSUM, &val, sizeof(val)) < 0)
141 // This is required by RFC 4861
143 if (setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &val, sizeof(val)) < 0)
146 // Receive multicast hops
148 if (setsockopt(sock, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &val, sizeof(val)) < 0)
151 // Bind to one device
152 if (setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname)) < 0)
156 if (fcntl(sock, F_SETOWN, ourpid) < 0)
159 val = fcntl(sock, F_GETFL);
163 if (fcntl(sock, F_SETFL, val | O_ASYNC) < 0)
167 signal(SIGALRM, ra_send_rs);
182 static void ra_send_rs(int signal __attribute__((unused)))
184 const struct sockaddr_in6 dest = {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, if_index};
185 const struct icmpv6_opt llnull = {ND_OPT_SOURCE_LINKADDR, 1, {0}};
188 if ((rs_attempt % 2 == 0) && memcmp(&rs.lladdr, &llnull, sizeof(llnull)))
191 len = sizeof(struct icmp6_hdr);
193 if (sendto(sock, &rs, len, MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest)) < 0)
194 syslog(LOG_ERR, "Failed to send RS (%s)", strerror(errno));
196 if (++rs_attempt <= 3)
200 static int16_t pref_to_priority(uint8_t flags)
202 flags = (flags >> 3) & 0x03;
204 return (flags == 0x0) ? 512 : (flags == 0x1) ? 384 :
205 (flags == 0x3) ? 640 : -1;
208 bool ra_link_up(void)
210 static bool firstcall = true;
213 struct ifinfomsg msg;
220 read = recv(rtnl, &resp, sizeof(resp), MSG_DONTWAIT);
222 if (read < 0 || !NLMSG_OK(&resp.hdr, (size_t)read) ||
223 resp.hdr.nlmsg_type != RTM_NEWLINK ||
224 resp.msg.ifi_index != if_index)
227 ssize_t alen = NLMSG_PAYLOAD(&resp.hdr, sizeof(resp.msg));
228 for (struct rtattr *rta = (struct rtattr*)(resp.pad);
229 RTA_OK(rta, alen); rta = RTA_NEXT(rta, alen)) {
230 if (rta->rta_type == IFLA_ADDRESS &&
231 RTA_PAYLOAD(rta) >= sizeof(rs.lladdr.data))
232 memcpy(rs.lladdr.data, RTA_DATA(rta), sizeof(rs.lladdr.data));
235 bool hascarrier = resp.msg.ifi_flags & IFF_LOWER_UP;
236 if (!firstcall && nocarrier != !hascarrier)
239 nocarrier = !hascarrier;
244 syslog(LOG_NOTICE, "carrier => %i event on %s", (int)!nocarrier, if_name);
253 static bool ra_icmpv6_valid(struct sockaddr_in6 *source, int hlim, uint8_t *data, size_t len)
255 struct icmp6_hdr *hdr = (struct icmp6_hdr*)data;
256 struct icmpv6_opt *opt, *end = (struct icmpv6_opt*)&data[len];
258 if (hlim != 255 || len < sizeof(*hdr) || hdr->icmp6_code)
261 switch (hdr->icmp6_type) {
262 case ND_ROUTER_ADVERT:
263 if (!IN6_IS_ADDR_LINKLOCAL(&source->sin6_addr))
266 opt = (struct icmpv6_opt*)((struct nd_router_advert*)data + 1);
273 icmpv6_for_each_option(opt, opt, end)
279 static bool ra_set_hoplimit(int val)
281 if (val > 0 && val != ra_hoplimit) {
289 static bool ra_set_mtu(int val)
291 if (val >= 1280 && val <= 65535 && ra_mtu != val) {
299 static bool ra_set_reachable(int val)
301 if (val > 0 && val <= 3600000 && ra_reachable != val) {
309 static bool ra_set_retransmit(int val)
311 if (val > 0 && val <= 60000 && ra_retransmit != val) {
319 int ra_get_hoplimit(void)
329 int ra_get_reachable(void)
334 int ra_get_retransmit(void)
336 return ra_retransmit;
339 bool ra_process(void)
342 bool changed = false;
343 uint8_t buf[1500] _aligned(4);
346 uint8_t buf[CMSG_SPACE(sizeof(int))];
348 struct nd_router_advert *adv = (struct nd_router_advert*)buf;
349 struct odhcp6c_entry *entry = alloca(sizeof(*entry) + 256);
350 const struct in6_addr any = IN6ADDR_ANY_INIT;
352 memset(entry, 0, sizeof(*entry));
354 if (IN6_IS_ADDR_UNSPECIFIED(&lladdr)) {
355 struct sockaddr_in6 addr = {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, if_index};
356 socklen_t alen = sizeof(addr);
357 int sock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
360 if (!connect(sock, (struct sockaddr*)&addr, sizeof(addr)) &&
361 !getsockname(sock, (struct sockaddr*)&addr, &alen))
362 lladdr = addr.sin6_addr;
369 struct sockaddr_in6 from;
370 struct iovec iov = {buf, sizeof(buf)};
371 struct msghdr msg = {
372 .msg_name = (void *) &from,
373 .msg_namelen = sizeof(from),
376 .msg_control = cmsg_buf.buf,
377 .msg_controllen = sizeof(cmsg_buf),
381 ssize_t len = recvmsg(sock, &msg, MSG_DONTWAIT);
385 if (IN6_IS_ADDR_UNSPECIFIED(&lladdr))
389 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
390 ch = CMSG_NXTHDR(&msg, ch))
391 if (ch->cmsg_level == IPPROTO_IPV6 &&
392 ch->cmsg_type == IPV6_HOPLIMIT)
393 memcpy(&hlim, CMSG_DATA(ch), sizeof(hlim));
395 if (!ra_icmpv6_valid(&from, hlim, buf, len))
398 // Stop sending solicits
399 if (rs_attempt > 0) {
408 uint32_t router_valid = ntohs(adv->nd_ra_router_lifetime);
410 // Parse default route
413 entry->router = from.sin6_addr;
414 entry->priority = pref_to_priority(adv->nd_ra_flags_reserved);
415 if (entry->priority < 0)
416 entry->priority = pref_to_priority(0);
418 entry->valid = router_valid;
419 entry->preferred = entry->valid;
420 changed |= odhcp6c_update_entry(STATE_RA_ROUTE, entry,
421 0, ra_holdoff_interval);
424 changed |= ra_set_hoplimit(adv->nd_ra_curhoplimit);
426 // Parse ND parameters
427 changed |= ra_set_reachable(ntohl(adv->nd_ra_reachable));
428 changed |= ra_set_retransmit(ntohl(adv->nd_ra_retransmit));
431 struct icmpv6_opt *opt;
432 icmpv6_for_each_option(opt, &adv[1], &buf[len]) {
433 if (opt->type == ND_OPT_MTU) {
434 uint32_t *mtu = (uint32_t*)&opt->data[2];
435 changed |= ra_set_mtu(ntohl(*mtu));
436 } else if (opt->type == ND_OPT_ROUTE_INFORMATION && opt->len <= 3) {
437 struct icmpv6_opt_route_info *ri = (struct icmpv6_opt_route_info *)opt;
439 if (ri->prefix_len > 128) {
441 } else if (ri->prefix_len > 64) {
444 } else if (ri->prefix_len > 0) {
449 entry->router = from.sin6_addr;
451 entry->priority = pref_to_priority(ri->flags);
452 entry->length = ri->prefix_len;
453 entry->valid = ntohl(ri->lifetime);
454 memcpy(&entry->target, ri->prefix, (ri->len - 1) * 8);
456 if (IN6_IS_ADDR_LINKLOCAL(&entry->target)
457 || IN6_IS_ADDR_LOOPBACK(&entry->target)
458 || IN6_IS_ADDR_MULTICAST(&entry->target))
461 if (entry->priority > 0)
462 changed |= odhcp6c_update_entry(STATE_RA_ROUTE, entry,
463 0, ra_holdoff_interval);
464 } else if (opt->type == ND_OPT_PREFIX_INFORMATION && opt->len == 4) {
465 struct nd_opt_prefix_info *pinfo = (struct nd_opt_prefix_info*)opt;
467 entry->target = pinfo->nd_opt_pi_prefix;
468 entry->priority = 256;
469 entry->length = pinfo->nd_opt_pi_prefix_len;
470 entry->valid = ntohl(pinfo->nd_opt_pi_valid_time);
471 entry->preferred = ntohl(pinfo->nd_opt_pi_preferred_time);
473 if (entry->length > 128 || IN6_IS_ADDR_LINKLOCAL(&entry->target)
474 || IN6_IS_ADDR_LOOPBACK(&entry->target)
475 || IN6_IS_ADDR_MULTICAST(&entry->target)
476 || entry->valid < entry->preferred)
479 if (pinfo->nd_opt_pi_flags_reserved & ND_OPT_PI_FLAG_ONLINK)
480 changed |= odhcp6c_update_entry(STATE_RA_ROUTE, entry,
481 7200, ra_holdoff_interval);
483 if (!(pinfo->nd_opt_pi_flags_reserved & ND_OPT_PI_FLAG_AUTO) ||
484 pinfo->nd_opt_pi_prefix_len != 64)
487 entry->target.s6_addr32[2] = lladdr.s6_addr32[2];
488 entry->target.s6_addr32[3] = lladdr.s6_addr32[3];
490 changed |= odhcp6c_update_entry(STATE_RA_PREFIX, entry,
491 7200, ra_holdoff_interval);
492 } else if (opt->type == ND_OPT_RECURSIVE_DNS && opt->len > 2) {
493 entry->router = from.sin6_addr;
496 uint32_t *valid = (uint32_t*)&opt->data[2];
497 entry->valid = ntohl(*valid);
498 entry->preferred = 0;
500 for (ssize_t i = 0; i < (opt->len - 1) / 2; ++i) {
501 memcpy(&entry->target, &opt->data[6 + i * sizeof(entry->target)],
502 sizeof(entry->target));
503 changed |= odhcp6c_update_entry(STATE_RA_DNS, entry,
504 0, ra_holdoff_interval);
506 } else if (opt->type == ND_OPT_DNSSL && opt->len > 1) {
507 uint32_t *valid = (uint32_t*)&opt->data[2];
508 uint8_t *buf = &opt->data[6];
509 uint8_t *end = &buf[(opt->len - 1) * 8];
511 entry->router = from.sin6_addr;
512 entry->valid = ntohl(*valid);
515 int len = dn_expand(buf, end, buf, (char*)entry->auxtarget, 256);
520 entry->auxlen = strlen((char*)entry->auxtarget);
522 if (entry->auxlen == 0)
525 changed |= odhcp6c_update_entry(STATE_RA_SEARCH, entry,
526 0, ra_holdoff_interval);
532 if (ra_options & RA_RDNSS_DEFAULT_LIFETIME) {
533 int states[2] = {STATE_RA_DNS, STATE_RA_SEARCH};
535 for (size_t i = 0; i < 2; ++i) {
537 uint8_t *start = odhcp6c_get_state(states[i], &ra_dns_len);
539 for (struct odhcp6c_entry *c = (struct odhcp6c_entry*)start;
540 (uint8_t*)c < &start[ra_dns_len] &&
541 (uint8_t*)odhcp6c_next_entry(c) <= &start[ra_dns_len];
542 c = odhcp6c_next_entry(c)) {
543 if (IN6_ARE_ADDR_EQUAL(&c->router, &from.sin6_addr) &&
544 c->valid > router_valid)
545 c->valid = router_valid;
554 return found && changed;