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.
29 #include <arpa/inet.h>
31 #include <netinet/ip6.h>
32 #include <netpacket/packet.h>
33 #include <linux/netlink.h>
34 #include <linux/if_addr.h>
35 #include <linux/neighbour.h>
36 #include <linux/rtnetlink.h>
38 #include <sys/socket.h>
39 #include <sys/ioctl.h>
40 #include <sys/epoll.h>
41 #include <sys/types.h>
43 #include <sys/syscall.h>
45 #include <netlink/msg.h>
46 #include <netlink/socket.h>
47 #include <netlink/attr.h>
48 #include <libubox/uloop.h>
53 static int ioctl_sock;
54 static struct nl_sock *rtnl_socket = NULL;
55 static int urandom_fd = -1;
57 static void sighandler(_unused int signal)
62 static void print_usage(const char *app)
66 " -h, --help Print this help\n"
67 " -l level Specify log level 0..7 (default %d)\n",
72 int main(int argc, char **argv)
74 openlog("odhcpd", LOG_PERROR | LOG_PID, LOG_DAEMON);
77 while ((opt = getopt(argc, argv, "hl:")) != -1) {
83 config.log_level = (atoi(optarg) & LOG_PRIMASK);
84 fprintf(stderr, "Log level set to %d\n", config.log_level);
88 setlogmask(LOG_UPTO(config.log_level));
92 syslog(LOG_ERR, "Must be run as root!");
96 ioctl_sock = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
98 if (!(rtnl_socket = odhcpd_create_nl_socket(NETLINK_ROUTE))) {
99 syslog(LOG_ERR, "Unable to open nl socket: %s", strerror(errno));
103 if ((urandom_fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC)) < 0)
106 signal(SIGUSR1, SIG_IGN);
107 signal(SIGINT, sighandler);
108 signal(SIGTERM, sighandler);
119 #ifdef DHCPV4_SUPPORT
128 struct nl_sock *odhcpd_create_nl_socket(int protocol)
130 struct nl_sock *nl_sock;
132 nl_sock = nl_socket_alloc();
136 if (nl_connect(nl_sock, protocol) < 0)
143 nl_socket_free(nl_sock);
149 // Read IPv6 MTU for interface
150 int odhcpd_get_interface_config(const char *ifname, const char *what)
153 const char *sysctl_pattern = "/proc/sys/net/ipv6/conf/%s/%s";
154 snprintf(buf, sizeof(buf), sysctl_pattern, ifname, what);
156 int fd = open(buf, O_RDONLY);
157 ssize_t len = read(fd, buf, sizeof(buf) - 1);
168 // Read IPv6 MAC for interface
169 int odhcpd_get_mac(const struct interface *iface, uint8_t mac[6])
172 memset(&ifr, 0, sizeof(ifr));
173 strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name));
174 if (ioctl(ioctl_sock, SIOCGIFHWADDR, &ifr) < 0)
176 memcpy(mac, ifr.ifr_hwaddr.sa_data, 6);
181 // Forwards a packet on a specific interface
182 ssize_t odhcpd_send(int socket, struct sockaddr_in6 *dest,
183 struct iovec *iov, size_t iov_len,
184 const struct interface *iface)
187 uint8_t cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))] = {0};
188 struct msghdr msg = {
189 .msg_name = (void *) dest,
190 .msg_namelen = sizeof(*dest),
192 .msg_iovlen = iov_len,
193 .msg_control = cmsg_buf,
194 .msg_controllen = sizeof(cmsg_buf),
198 // Set control data (define destination interface)
199 struct cmsghdr *chdr = CMSG_FIRSTHDR(&msg);
200 chdr->cmsg_level = IPPROTO_IPV6;
201 chdr->cmsg_type = IPV6_PKTINFO;
202 chdr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
203 struct in6_pktinfo *pktinfo = (struct in6_pktinfo*)CMSG_DATA(chdr);
204 pktinfo->ipi6_ifindex = iface->ifindex;
206 // Also set scope ID if link-local
207 if (IN6_IS_ADDR_LINKLOCAL(&dest->sin6_addr)
208 || IN6_IS_ADDR_MC_LINKLOCAL(&dest->sin6_addr))
209 dest->sin6_scope_id = iface->ifindex;
211 char ipbuf[INET6_ADDRSTRLEN];
212 inet_ntop(AF_INET6, &dest->sin6_addr, ipbuf, sizeof(ipbuf));
214 ssize_t sent = sendmsg(socket, &msg, MSG_DONTWAIT);
216 syslog(LOG_NOTICE, "Failed to send to %s%%%s (%s)",
217 ipbuf, iface->ifname, strerror(errno));
219 syslog(LOG_DEBUG, "Sent %li bytes to %s%%%s",
220 (long)sent, ipbuf, iface->ifname);
226 struct odhcpd_ipaddr *addrs;
232 static int cb_valid_handler(struct nl_msg *msg, void *arg)
234 struct addr_info *ctxt = (struct addr_info *)arg;
235 struct nlmsghdr *hdr = nlmsg_hdr(msg);
236 struct ifaddrmsg *ifa;
237 struct nlattr *nla[__IFA_MAX];
239 if (hdr->nlmsg_type != RTM_NEWADDR || ctxt->ret >= (ssize_t)ctxt->addrs_sz)
242 ifa = NLMSG_DATA(hdr);
243 if (ifa->ifa_scope != RT_SCOPE_UNIVERSE ||
244 (ctxt->ifindex && ifa->ifa_index != (unsigned)ctxt->ifindex))
247 nlmsg_parse(hdr, sizeof(*ifa), nla, __IFA_MAX - 1, NULL);
248 if (!nla[IFA_ADDRESS])
251 memset(&ctxt->addrs[ctxt->ret], 0, sizeof(ctxt->addrs[ctxt->ret]));
252 ctxt->addrs[ctxt->ret].prefix = ifa->ifa_prefixlen;
254 nla_memcpy(&ctxt->addrs[ctxt->ret].addr, nla[IFA_ADDRESS],
255 sizeof(ctxt->addrs[ctxt->ret].addr));
257 if (nla[IFA_CACHEINFO]) {
258 struct ifa_cacheinfo *ifc = nla_data(nla[IFA_CACHEINFO]);
260 ctxt->addrs[ctxt->ret].preferred = ifc->ifa_prefered;
261 ctxt->addrs[ctxt->ret].valid = ifc->ifa_valid;
264 if (ifa->ifa_flags & IFA_F_DEPRECATED)
265 ctxt->addrs[ctxt->ret].preferred = 0;
272 static int cb_finish_handler(_unused struct nl_msg *msg, void *arg)
274 struct addr_info *ctxt = (struct addr_info *)arg;
281 static int cb_error_handler(_unused struct sockaddr_nl *nla, struct nlmsgerr *err,
284 struct addr_info *ctxt = (struct addr_info *)arg;
287 ctxt->ret = err->error;
292 // Detect an IPV6-address currently assigned to the given interface
293 ssize_t odhcpd_get_interface_addresses(int ifindex,
294 struct odhcpd_ipaddr *addrs, size_t cnt)
297 struct ifaddrmsg ifa = {
298 .ifa_family = AF_INET6,
302 .ifa_index = ifindex, };
303 struct nl_cb *cb = nl_cb_alloc(NL_CB_DEFAULT);
304 struct addr_info ctxt = {
317 msg = nlmsg_alloc_simple(RTM_GETADDR, NLM_F_REQUEST | NLM_F_DUMP);
324 nlmsg_append(msg, &ifa, sizeof(ifa), 0);
326 nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, cb_valid_handler, &ctxt);
327 nl_cb_set(cb, NL_CB_FINISH, NL_CB_CUSTOM, cb_finish_handler, &ctxt);
328 nl_cb_err(cb, NL_CB_CUSTOM, cb_error_handler, &ctxt);
330 nl_send_auto_complete(rtnl_socket, msg);
331 while (ctxt.pending > 0)
332 nl_recvmsgs(rtnl_socket, cb);
341 static int odhcpd_get_linklocal_interface_address(int ifindex, struct in6_addr *lladdr)
344 struct sockaddr_in6 addr = {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, ifindex};
345 socklen_t alen = sizeof(addr);
346 int sock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
348 if (!connect(sock, (struct sockaddr*)&addr, sizeof(addr)) &&
349 !getsockname(sock, (struct sockaddr*)&addr, &alen)) {
350 *lladdr = addr.sin6_addr;
360 * DNS address selection criteria order :
361 * - use IPv6 address with valid lifetime if none is yet selected
362 * - use IPv6 address with a preferred lifetime if the already selected IPv6 address is deprecated
363 * - use an IPv6 ULA address if the already selected IPv6 address is not an ULA address
364 * - use the IPv6 address with the longest preferred lifetime
366 int odhcpd_get_interface_dns_addr(const struct interface *iface, struct in6_addr *addr)
368 time_t now = odhcpd_time();
371 for (size_t i = 0; i < iface->ia_addr_len; ++i) {
372 if (iface->ia_addr[i].valid <= (uint32_t)now)
380 if (iface->ia_addr[m].preferred >= (uint32_t)now &&
381 iface->ia_addr[i].preferred < (uint32_t)now)
384 if (IN6_IS_ADDR_ULA(&iface->ia_addr[i].addr)) {
385 if (!IN6_IS_ADDR_ULA(&iface->ia_addr[m].addr)) {
389 } else if (IN6_IS_ADDR_ULA(&iface->ia_addr[m].addr))
392 if (iface->ia_addr[i].preferred > iface->ia_addr[m].preferred)
397 *addr = iface->ia_addr[m].addr;
401 return odhcpd_get_linklocal_interface_address(iface->ifindex, addr);
404 int odhcpd_setup_route(const struct in6_addr *addr, const int prefixlen,
405 const struct interface *iface, const struct in6_addr *gw,
406 const uint32_t metric, const bool add)
410 .rtm_family = AF_INET6,
411 .rtm_dst_len = prefixlen,
413 .rtm_table = RT_TABLE_MAIN,
414 .rtm_protocol = (add ? RTPROT_STATIC : RTPROT_UNSPEC),
415 .rtm_scope = (add ? (gw ? RT_SCOPE_UNIVERSE : RT_SCOPE_LINK) : RT_SCOPE_NOWHERE),
416 .rtm_type = (add ? RTN_UNICAST : RTN_UNSPEC),
420 msg = nlmsg_alloc_simple(add ? RTM_NEWROUTE : RTM_DELROUTE,
421 add ? NLM_F_CREATE | NLM_F_REPLACE : 0);
425 nlmsg_append(msg, &rtm, sizeof(rtm), 0);
427 nla_put(msg, RTA_DST, sizeof(*addr), addr);
428 nla_put_u32(msg, RTA_OIF, iface->ifindex);
429 nla_put_u32(msg, RTA_PRIORITY, metric);
432 nla_put(msg, RTA_GATEWAY, sizeof(*gw), gw);
434 ret = nl_send_auto_complete(rtnl_socket, msg);
440 return nl_wait_for_ack(rtnl_socket);
443 int odhcpd_setup_proxy_neigh(const struct in6_addr *addr,
444 const struct interface *iface, const bool add)
448 .ndm_family = AF_INET6,
449 .ndm_flags = NTF_PROXY,
450 .ndm_ifindex = iface->ifindex,
452 int ret = 0, flags = NLM_F_REQUEST;
455 flags |= NLM_F_REPLACE | NLM_F_CREATE;
457 msg = nlmsg_alloc_simple(add ? RTM_NEWNEIGH : RTM_DELNEIGH, flags);
461 nlmsg_append(msg, &ndm, sizeof(ndm), 0);
463 nla_put(msg, NDA_DST, sizeof(*addr), addr);
465 ret = nl_send_auto_complete(rtnl_socket, msg);
471 return nl_wait_for_ack(rtnl_socket);
474 struct interface* odhcpd_get_interface_by_index(int ifindex)
476 struct interface *iface;
477 list_for_each_entry(iface, &interfaces, head)
478 if (iface->ifindex == ifindex)
485 struct interface* odhcpd_get_interface_by_name(const char *name)
487 struct interface *iface;
488 list_for_each_entry(iface, &interfaces, head)
489 if (!strcmp(iface->ifname, name))
496 struct interface* odhcpd_get_master_interface(void)
498 struct interface *iface;
499 list_for_each_entry(iface, &interfaces, head)
507 // Convenience function to receive and do basic validation of packets
508 static void odhcpd_receive_packets(struct uloop_fd *u, _unused unsigned int events)
510 struct odhcpd_event *e = container_of(u, struct odhcpd_event, uloop);
512 uint8_t data_buf[RELAYD_BUFFER_SIZE], cmsg_buf[128];
514 struct sockaddr_in6 in6;
515 struct sockaddr_in in;
516 struct sockaddr_ll ll;
517 struct sockaddr_nl nl;
522 socklen_t ret_len = sizeof(ret);
523 getsockopt(u->fd, SOL_SOCKET, SO_ERROR, &ret, &ret_len);
526 e->handle_error(e, ret);
535 struct iovec iov = {data_buf, sizeof(data_buf)};
536 struct msghdr msg = {
537 .msg_name = (void *) &addr,
538 .msg_namelen = sizeof(addr),
541 .msg_control = cmsg_buf,
542 .msg_controllen = sizeof(cmsg_buf),
546 ssize_t len = recvmsg(u->fd, &msg, MSG_DONTWAIT);
555 // Extract destination interface
559 struct in6_pktinfo *pktinfo;
560 struct in_pktinfo *pkt4info;
561 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL; ch = CMSG_NXTHDR(&msg, ch)) {
562 if (ch->cmsg_level == IPPROTO_IPV6 &&
563 ch->cmsg_type == IPV6_PKTINFO) {
564 pktinfo = (struct in6_pktinfo*)CMSG_DATA(ch);
565 destiface = pktinfo->ipi6_ifindex;
566 dest = &pktinfo->ipi6_addr;
567 } else if (ch->cmsg_level == IPPROTO_IP &&
568 ch->cmsg_type == IP_PKTINFO) {
569 pkt4info = (struct in_pktinfo*)CMSG_DATA(ch);
570 destiface = pkt4info->ipi_ifindex;
571 dest = &pkt4info->ipi_addr;
572 } else if (ch->cmsg_level == IPPROTO_IPV6 &&
573 ch->cmsg_type == IPV6_HOPLIMIT) {
574 hlim = (int*)CMSG_DATA(ch);
578 // Check hoplimit if received
579 if (hlim && *hlim != 255)
582 // Detect interface for packet sockets
583 if (addr.ll.sll_family == AF_PACKET)
584 destiface = addr.ll.sll_ifindex;
586 struct interface *iface =
587 odhcpd_get_interface_by_index(destiface);
589 if (!iface && addr.nl.nl_family != AF_NETLINK)
592 char ipbuf[INET6_ADDRSTRLEN] = "kernel";
593 if (addr.ll.sll_family == AF_PACKET &&
594 len >= (ssize_t)sizeof(struct ip6_hdr))
595 inet_ntop(AF_INET6, &data_buf[8], ipbuf, sizeof(ipbuf));
596 else if (addr.in6.sin6_family == AF_INET6)
597 inet_ntop(AF_INET6, &addr.in6.sin6_addr, ipbuf, sizeof(ipbuf));
598 else if (addr.in.sin_family == AF_INET)
599 inet_ntop(AF_INET, &addr.in.sin_addr, ipbuf, sizeof(ipbuf));
601 syslog(LOG_DEBUG, "Received %li Bytes from %s%%%s", (long)len,
602 ipbuf, (iface) ? iface->ifname : "netlink");
604 e->handle_dgram(&addr, data_buf, len, iface, dest);
608 // Register events for the multiplexer
609 int odhcpd_register(struct odhcpd_event *event)
611 event->uloop.cb = odhcpd_receive_packets;
612 return uloop_fd_add(&event->uloop, ULOOP_READ |
613 ((event->handle_error) ? ULOOP_ERROR_CB : 0));
616 int odhcpd_deregister(struct odhcpd_event *event)
618 event->uloop.cb = NULL;
619 return uloop_fd_delete(&event->uloop);
622 void odhcpd_process(struct odhcpd_event *event)
624 odhcpd_receive_packets(&event->uloop, 0);
627 int odhcpd_urandom(void *data, size_t len)
629 return read(urandom_fd, data, len);
633 time_t odhcpd_time(void)
636 syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &ts);
641 static const char hexdigits[] = "0123456789abcdef";
642 static const int8_t hexvals[] = {
643 -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
644 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
645 -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
646 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
647 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
648 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
649 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
650 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
653 ssize_t odhcpd_unhexlify(uint8_t *dst, size_t len, const char *src)
656 for (c = 0; c < len && src[0] && src[1]; ++c) {
657 int8_t x = (int8_t)*src++;
658 int8_t y = (int8_t)*src++;
659 if (x < 0 || (x = hexvals[x]) < 0
660 || y < 0 || (y = hexvals[y]) < 0)
663 while (((int8_t)*src) < 0 ||
664 (*src && hexvals[(uint8_t)*src] < 0))
672 void odhcpd_hexlify(char *dst, const uint8_t *src, size_t len)
674 for (size_t i = 0; i < len; ++i) {
675 *dst++ = hexdigits[src[i] >> 4];
676 *dst++ = hexdigits[src[i] & 0x0f];
682 int odhcpd_bmemcmp(const void *av, const void *bv, size_t bits)
684 const uint8_t *a = av, *b = bv;
685 size_t bytes = bits / 8;
688 int res = memcmp(a, b, bytes);
689 if (res == 0 && bits > 0)
690 res = (a[bytes] >> (8 - bits)) - (b[bytes] >> (8 - bits));
696 void odhcpd_bmemcpy(void *av, const void *bv, size_t bits)
699 const uint8_t *b = bv;
701 size_t bytes = bits / 8;
706 uint8_t mask = (1 << (8 - bits)) - 1;
707 a[bytes] = (a[bytes] & mask) | ((~mask) & b[bytes]);