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.
28 #include <arpa/inet.h>
30 #include <netinet/ip6.h>
31 #include <netpacket/packet.h>
32 #include <linux/rtnetlink.h>
34 #include <sys/socket.h>
35 #include <sys/ioctl.h>
36 #include <sys/epoll.h>
37 #include <sys/types.h>
39 #include <sys/syscall.h>
41 #include <libubox/uloop.h>
46 static int ioctl_sock;
47 static int rtnl_socket = -1;
48 static int rtnl_seq = 0;
49 static int urandom_fd = -1;
52 static void sighandler(_unused int signal)
57 static void print_usage(const char *app)
61 " -h, --help Print this help\n"
62 " -l level Specify log level 0..7 (default %d)\n",
67 int main(int argc, char **argv)
69 openlog("odhcpd", LOG_PERROR | LOG_PID, LOG_DAEMON);
71 int log_level = LOG_WARNING;
72 while ((opt = getopt(argc, argv, "hl:")) != -1) {
78 log_level = atoi(optarg);
79 fprintf(stderr, "Log level set to %d\n", log_level);
83 setlogmask(LOG_UPTO(log_level));
87 syslog(LOG_ERR, "Must be run as root!");
91 ioctl_sock = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
93 if ((rtnl_socket = odhcpd_open_rtnl()) < 0) {
94 syslog(LOG_ERR, "Unable to open socket: %s", strerror(errno));
98 if ((urandom_fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC)) < 0)
101 signal(SIGUSR1, SIG_IGN);
102 signal(SIGINT, sighandler);
103 signal(SIGTERM, sighandler);
121 int odhcpd_open_rtnl(void)
123 int sock = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, NETLINK_ROUTE);
125 // Connect to the kernel netlink interface
126 struct sockaddr_nl nl = {.nl_family = AF_NETLINK};
127 if (connect(sock, (struct sockaddr*)&nl, sizeof(nl))) {
128 syslog(LOG_ERR, "Failed to connect to kernel rtnetlink: %s",
137 // Read IPv6 MTU for interface
138 int odhcpd_get_interface_config(const char *ifname, const char *what)
141 const char *sysctl_pattern = "/proc/sys/net/ipv6/conf/%s/%s";
142 snprintf(buf, sizeof(buf), sysctl_pattern, ifname, what);
144 int fd = open(buf, O_RDONLY);
145 ssize_t len = read(fd, buf, sizeof(buf) - 1);
156 // Read IPv6 MAC for interface
157 int odhcpd_get_mac(const struct interface *iface, uint8_t mac[6])
160 memset(&ifr, 0, sizeof(ifr));
161 strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name));
162 if (ioctl(ioctl_sock, SIOCGIFHWADDR, &ifr) < 0)
164 memcpy(mac, ifr.ifr_hwaddr.sa_data, 6);
169 // Forwards a packet on a specific interface
170 ssize_t odhcpd_send(int socket, struct sockaddr_in6 *dest,
171 struct iovec *iov, size_t iov_len,
172 const struct interface *iface)
175 uint8_t cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))] = {0};
176 struct msghdr msg = {
177 .msg_name = (void *) dest,
178 .msg_namelen = sizeof(*dest),
180 .msg_iovlen = iov_len,
181 .msg_control = cmsg_buf,
182 .msg_controllen = sizeof(cmsg_buf),
186 // Set control data (define destination interface)
187 struct cmsghdr *chdr = CMSG_FIRSTHDR(&msg);
188 chdr->cmsg_level = IPPROTO_IPV6;
189 chdr->cmsg_type = IPV6_PKTINFO;
190 chdr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
191 struct in6_pktinfo *pktinfo = (struct in6_pktinfo*)CMSG_DATA(chdr);
192 pktinfo->ipi6_ifindex = iface->ifindex;
194 // Also set scope ID if link-local
195 if (IN6_IS_ADDR_LINKLOCAL(&dest->sin6_addr)
196 || IN6_IS_ADDR_MC_LINKLOCAL(&dest->sin6_addr))
197 dest->sin6_scope_id = iface->ifindex;
199 char ipbuf[INET6_ADDRSTRLEN];
200 inet_ntop(AF_INET6, &dest->sin6_addr, ipbuf, sizeof(ipbuf));
202 ssize_t sent = sendmsg(socket, &msg, MSG_DONTWAIT);
204 syslog(LOG_NOTICE, "Failed to send to %s%%%s (%s)",
205 ipbuf, iface->ifname, strerror(errno));
207 syslog(LOG_DEBUG, "Sent %li bytes to %s%%%s",
208 (long)sent, ipbuf, iface->ifname);
213 // Detect an IPV6-address currently assigned to the given interface
214 ssize_t odhcpd_get_interface_addresses(int ifindex,
215 struct odhcpd_ipaddr *addrs, size_t cnt)
219 struct ifaddrmsg ifa;
220 } req = {{sizeof(req), RTM_GETADDR, NLM_F_REQUEST | NLM_F_DUMP,
221 ++rtnl_seq, 0}, {AF_INET6, 0, 0, 0, ifindex}};
222 if (send(rtnl_socket, &req, sizeof(req), 0) < (ssize_t)sizeof(req))
226 ssize_t len = 0, ret = 0;
228 for (struct nlmsghdr *nhm = NULL; ; nhm = NLMSG_NEXT(nhm, len)) {
229 while (len < 0 || !NLMSG_OK(nhm, (size_t)len)) {
230 len = recv(rtnl_socket, buf, sizeof(buf), 0);
231 nhm = (struct nlmsghdr*)buf;
232 if (len < 0 || !NLMSG_OK(nhm, (size_t)len)) {
240 if (nhm->nlmsg_type != RTM_NEWADDR)
243 // Skip address but keep clearing socket buffer
244 if (ret >= (ssize_t)cnt)
247 struct ifaddrmsg *ifa = NLMSG_DATA(nhm);
248 if (ifa->ifa_scope != RT_SCOPE_UNIVERSE ||
249 (ifindex && ifa->ifa_index != (unsigned)ifindex))
252 struct rtattr *rta = (struct rtattr*)&ifa[1];
253 size_t alen = NLMSG_PAYLOAD(nhm, sizeof(*ifa));
254 memset(&addrs[ret], 0, sizeof(addrs[ret]));
255 addrs[ret].prefix = ifa->ifa_prefixlen;
257 while (RTA_OK(rta, alen)) {
258 if (rta->rta_type == IFA_ADDRESS) {
259 memcpy(&addrs[ret].addr, RTA_DATA(rta),
260 sizeof(struct in6_addr));
261 } else if (rta->rta_type == IFA_CACHEINFO) {
262 struct ifa_cacheinfo *ifc = RTA_DATA(rta);
263 addrs[ret].preferred = ifc->ifa_prefered;
264 addrs[ret].valid = ifc->ifa_valid;
267 rta = RTA_NEXT(rta, alen);
270 if (ifa->ifa_flags & IFA_F_DEPRECATED)
271 addrs[ret].preferred = 0;
279 int odhcpd_get_linklocal_interface_address(int ifindex, struct in6_addr *lladdr)
282 struct sockaddr_in6 addr = {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, ifindex};
283 socklen_t alen = sizeof(addr);
284 int sock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
286 if (!connect(sock, (struct sockaddr*)&addr, sizeof(addr)) &&
287 !getsockname(sock, (struct sockaddr*)&addr, &alen)) {
288 *lladdr = addr.sin6_addr;
296 void odhcpd_setup_route(const struct in6_addr *addr, int prefixlen,
297 const struct interface *iface, const struct in6_addr *gw,
298 int metric, bool add)
303 struct rtattr rta_dst;
304 struct in6_addr dst_addr;
305 struct rtattr rta_oif;
307 struct rtattr rta_table;
309 struct rtattr rta_prio;
311 struct rtattr rta_gw;
314 {sizeof(req), 0, NLM_F_REQUEST, ++rtnl_seq, 0},
315 {AF_INET6, prefixlen, 0, 0, 0, 0, 0, 0, 0},
316 {sizeof(struct rtattr) + sizeof(struct in6_addr), RTA_DST},
318 {sizeof(struct rtattr) + sizeof(uint32_t), RTA_OIF},
320 {sizeof(struct rtattr) + sizeof(uint32_t), RTA_TABLE},
322 {sizeof(struct rtattr) + sizeof(uint32_t), RTA_PRIORITY},
324 {sizeof(struct rtattr) + sizeof(struct in6_addr), RTA_GATEWAY},
332 req.nh.nlmsg_type = RTM_NEWROUTE;
333 req.nh.nlmsg_flags |= (NLM_F_CREATE | NLM_F_REPLACE);
334 req.rtm.rtm_protocol = RTPROT_STATIC;
335 req.rtm.rtm_scope = (gw) ? RT_SCOPE_UNIVERSE : RT_SCOPE_LINK;
336 req.rtm.rtm_type = RTN_UNICAST;
338 req.nh.nlmsg_type = RTM_DELROUTE;
339 req.rtm.rtm_scope = RT_SCOPE_NOWHERE;
342 req.nh.nlmsg_len = (gw) ? sizeof(req) : offsetof(struct req, rta_gw);
343 send(rtnl_socket, &req, req.nh.nlmsg_len, MSG_DONTWAIT);
346 struct interface* odhcpd_get_interface_by_index(int ifindex)
348 struct interface *iface;
349 list_for_each_entry(iface, &interfaces, head)
350 if (iface->ifindex == ifindex)
357 struct interface* odhcpd_get_interface_by_name(const char *name)
359 struct interface *iface;
360 list_for_each_entry(iface, &interfaces, head)
361 if (!strcmp(iface->ifname, name))
368 struct interface* odhcpd_get_master_interface(void)
370 struct interface *iface;
371 list_for_each_entry(iface, &interfaces, head)
379 // Convenience function to receive and do basic validation of packets
380 static void odhcpd_receive_packets(struct uloop_fd *u, _unused unsigned int events)
382 struct odhcpd_event *e = container_of(u, struct odhcpd_event, uloop);
384 uint8_t data_buf[RELAYD_BUFFER_SIZE], cmsg_buf[128];
386 struct sockaddr_in6 in6;
387 struct sockaddr_in in;
388 struct sockaddr_ll ll;
389 struct sockaddr_nl nl;
394 socklen_t ret_len = sizeof(ret);
395 getsockopt(u->fd, SOL_SOCKET, SO_ERROR, &ret, &ret_len);
398 e->handle_error(ret);
402 struct iovec iov = {data_buf, sizeof(data_buf)};
403 struct msghdr msg = {
404 .msg_name = (void *) &addr,
405 .msg_namelen = sizeof(addr),
408 .msg_control = cmsg_buf,
409 .msg_controllen = sizeof(cmsg_buf),
413 ssize_t len = recvmsg(u->fd, &msg, MSG_DONTWAIT);
422 // Extract destination interface
426 struct in6_pktinfo *pktinfo;
427 struct in_pktinfo *pkt4info;
428 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL; ch = CMSG_NXTHDR(&msg, ch)) {
429 if (ch->cmsg_level == IPPROTO_IPV6 &&
430 ch->cmsg_type == IPV6_PKTINFO) {
431 pktinfo = (struct in6_pktinfo*)CMSG_DATA(ch);
432 destiface = pktinfo->ipi6_ifindex;
433 dest = &pktinfo->ipi6_addr;
434 } else if (ch->cmsg_level == IPPROTO_IP &&
435 ch->cmsg_type == IP_PKTINFO) {
436 pkt4info = (struct in_pktinfo*)CMSG_DATA(ch);
437 destiface = pkt4info->ipi_ifindex;
438 dest = &pkt4info->ipi_addr;
439 } else if (ch->cmsg_level == IPPROTO_IPV6 &&
440 ch->cmsg_type == IPV6_HOPLIMIT) {
441 hlim = (int*)CMSG_DATA(ch);
445 // Check hoplimit if received
446 if (hlim && *hlim != 255)
449 // Detect interface for packet sockets
450 if (addr.ll.sll_family == AF_PACKET)
451 destiface = addr.ll.sll_ifindex;
453 struct interface *iface =
454 odhcpd_get_interface_by_index(destiface);
456 if (!iface && addr.nl.nl_family != AF_NETLINK)
459 char ipbuf[INET6_ADDRSTRLEN] = "kernel";
460 if (addr.ll.sll_family == AF_PACKET &&
461 len >= (ssize_t)sizeof(struct ip6_hdr))
462 inet_ntop(AF_INET6, &data_buf[8], ipbuf, sizeof(ipbuf));
463 else if (addr.in6.sin6_family == AF_INET6)
464 inet_ntop(AF_INET6, &addr.in6.sin6_addr, ipbuf, sizeof(ipbuf));
465 else if (addr.in.sin_family == AF_INET)
466 inet_ntop(AF_INET, &addr.in.sin_addr, ipbuf, sizeof(ipbuf));
468 syslog(LOG_DEBUG, "Received %li Bytes from %s%%%s", (long)len,
469 ipbuf, (iface) ? iface->ifname : "netlink");
471 e->handle_dgram(&addr, data_buf, len, iface, dest);
475 // Register events for the multiplexer
476 int odhcpd_register(struct odhcpd_event *event)
478 event->uloop.cb = odhcpd_receive_packets;
479 return uloop_fd_add(&event->uloop, ULOOP_READ |
480 ((event->handle_error) ? ULOOP_ERROR_CB : 0));
483 void odhcpd_process(struct odhcpd_event *event)
485 odhcpd_receive_packets(&event->uloop, 0);
488 int odhcpd_urandom(void *data, size_t len)
490 return read(urandom_fd, data, len);
494 time_t odhcpd_time(void)
497 syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &ts);
502 static const char hexdigits[] = "0123456789abcdef";
503 static const int8_t hexvals[] = {
504 -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
505 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
506 -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
507 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
508 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
509 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
510 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
511 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
514 ssize_t odhcpd_unhexlify(uint8_t *dst, size_t len, const char *src)
517 for (c = 0; c < len && src[0] && src[1]; ++c) {
518 int8_t x = (int8_t)*src++;
519 int8_t y = (int8_t)*src++;
520 if (x < 0 || (x = hexvals[x]) < 0
521 || y < 0 || (y = hexvals[y]) < 0)
524 while (((int8_t)*src) < 0 ||
525 (*src && hexvals[(uint8_t)*src] < 0))
533 void odhcpd_hexlify(char *dst, const uint8_t *src, size_t len)
535 for (size_t i = 0; i < len; ++i) {
536 *dst++ = hexdigits[src[i] >> 4];
537 *dst++ = hexdigits[src[i] & 0x0f];
543 int odhcpd_bmemcmp(const void *av, const void *bv, size_t bits)
545 const uint8_t *a = av, *b = bv;
546 size_t bytes = bits / 8;
549 int res = memcmp(a, b, bytes);
550 if (res == 0 && bits > 0)
551 res = (a[bytes] >> (8 - bits)) - (b[bytes] >> (8 - bits));
557 void odhcpd_bmemcpy(void *av, const void *bv, size_t bits)
560 const uint8_t *b = bv;
562 size_t bytes = bits / 8;
567 uint8_t mask = (1 << (8 - bits)) - 1;
568 a[bytes] = (a[bytes] & mask) | ((~mask) & b[bytes]);