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.
30 #include <arpa/inet.h>
32 #include <netinet/ip6.h>
33 #include <netpacket/packet.h>
34 #include <linux/netlink.h>
36 #include <sys/socket.h>
37 #include <sys/ioctl.h>
38 #include <sys/epoll.h>
39 #include <sys/types.h>
41 #include <sys/syscall.h>
43 #include <libubox/uloop.h>
48 static int ioctl_sock;
49 static int urandom_fd = -1;
51 static void sighandler(_unused int signal)
56 static void print_usage(const char *app)
60 " -h, --help Print this help\n"
61 " -l level Specify log level 0..7 (default %d)\n",
66 static bool ipv6_enabled(void)
68 int fd = socket(AF_INET6, SOCK_DGRAM, 0);
78 int main(int argc, char **argv)
80 openlog("odhcpd", LOG_PERROR | LOG_PID, LOG_DAEMON);
83 while ((opt = getopt(argc, argv, "hl:")) != -1) {
89 config.log_level = (atoi(optarg) & LOG_PRIMASK);
90 fprintf(stderr, "Log level set to %d\n", config.log_level);
94 setlogmask(LOG_UPTO(config.log_level));
98 syslog(LOG_ERR, "Must be run as root!");
102 ioctl_sock = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
107 if ((urandom_fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC)) < 0)
110 signal(SIGUSR1, SIG_IGN);
111 signal(SIGINT, sighandler);
112 signal(SIGTERM, sighandler);
117 if (ipv6_enabled()) {
127 #ifndef DHCPV4_SUPPORT
140 /* Read IPv6 MTU for interface */
141 int odhcpd_get_interface_config(const char *ifname, const char *what)
144 const char *sysctl_pattern = "/proc/sys/net/ipv6/conf/%s/%s";
145 snprintf(buf, sizeof(buf), sysctl_pattern, ifname, what);
147 int fd = open(buf, O_RDONLY);
151 ssize_t len = read(fd, buf, sizeof(buf) - 1);
162 /* Read IPv6 MAC for interface */
163 int odhcpd_get_mac(const struct interface *iface, uint8_t mac[6])
167 memset(&ifr, 0, sizeof(ifr));
168 strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name) - 1);
169 if (ioctl(ioctl_sock, SIOCGIFHWADDR, &ifr) < 0)
172 memcpy(mac, ifr.ifr_hwaddr.sa_data, 6);
177 /* Forwards a packet on a specific interface */
178 ssize_t odhcpd_send(int socket, struct sockaddr_in6 *dest,
179 struct iovec *iov, size_t iov_len,
180 const struct interface *iface)
182 /* Construct headers */
183 uint8_t cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))] = {0};
184 struct msghdr msg = {
185 .msg_name = (void *) dest,
186 .msg_namelen = sizeof(*dest),
188 .msg_iovlen = iov_len,
189 .msg_control = cmsg_buf,
190 .msg_controllen = sizeof(cmsg_buf),
194 /* Set control data (define destination interface) */
195 struct cmsghdr *chdr = CMSG_FIRSTHDR(&msg);
196 chdr->cmsg_level = IPPROTO_IPV6;
197 chdr->cmsg_type = IPV6_PKTINFO;
198 chdr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
199 struct in6_pktinfo *pktinfo = (struct in6_pktinfo*)CMSG_DATA(chdr);
200 pktinfo->ipi6_ifindex = iface->ifindex;
202 /* Also set scope ID if link-local */
203 if (IN6_IS_ADDR_LINKLOCAL(&dest->sin6_addr)
204 || IN6_IS_ADDR_MC_LINKLOCAL(&dest->sin6_addr))
205 dest->sin6_scope_id = iface->ifindex;
207 char ipbuf[INET6_ADDRSTRLEN];
208 inet_ntop(AF_INET6, &dest->sin6_addr, ipbuf, sizeof(ipbuf));
210 ssize_t sent = sendmsg(socket, &msg, MSG_DONTWAIT);
212 syslog(LOG_NOTICE, "Failed to send to %s%%%s (%m)",
213 ipbuf, iface->ifname);
215 syslog(LOG_DEBUG, "Sent %li bytes to %s%%%s",
216 (long)sent, ipbuf, iface->ifname);
221 static int odhcpd_get_linklocal_interface_address(int ifindex, struct in6_addr *lladdr)
224 struct sockaddr_in6 addr;
225 socklen_t alen = sizeof(addr);
226 int sock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
231 memset(&addr, 0, sizeof(addr));
232 addr.sin6_family = AF_INET6;
233 inet_pton(AF_INET6, ALL_IPV6_ROUTERS, &addr.sin6_addr);
234 addr.sin6_scope_id = ifindex;
236 if (!connect(sock, (struct sockaddr*)&addr, sizeof(addr)) &&
237 !getsockname(sock, (struct sockaddr*)&addr, &alen)) {
238 *lladdr = addr.sin6_addr;
247 * DNS address selection criteria order :
248 * - use IPv6 address with valid lifetime if none is yet selected
249 * - use IPv6 address with a preferred lifetime if the already selected IPv6 address is deprecated
250 * - use an IPv6 ULA address if the already selected IPv6 address is not an ULA address
251 * - use the IPv6 address with the longest preferred lifetime
253 int odhcpd_get_interface_dns_addr(const struct interface *iface, struct in6_addr *addr)
255 time_t now = odhcpd_time();
258 for (size_t i = 0; i < iface->addr6_len; ++i) {
259 if (iface->addr6[i].valid <= (uint32_t)now)
267 if (iface->addr6[m].preferred >= (uint32_t)now &&
268 iface->addr6[i].preferred < (uint32_t)now)
271 if (IN6_IS_ADDR_ULA(&iface->addr6[i].addr.in6)) {
272 if (!IN6_IS_ADDR_ULA(&iface->addr6[m].addr.in6)) {
276 } else if (IN6_IS_ADDR_ULA(&iface->addr6[m].addr.in6))
279 if (iface->addr6[i].preferred > iface->addr6[m].preferred)
284 *addr = iface->addr6[m].addr.in6;
288 return odhcpd_get_linklocal_interface_address(iface->ifindex, addr);
291 struct interface* odhcpd_get_interface_by_index(int ifindex)
293 struct interface *iface;
294 list_for_each_entry(iface, &interfaces, head)
295 if (iface->ifindex == ifindex)
302 struct interface* odhcpd_get_interface_by_name(const char *name)
304 struct interface *iface;
305 list_for_each_entry(iface, &interfaces, head)
306 if (!strcmp(iface->ifname, name))
313 struct interface* odhcpd_get_master_interface(void)
315 struct interface *iface;
316 list_for_each_entry(iface, &interfaces, head)
324 /* Convenience function to receive and do basic validation of packets */
325 static void odhcpd_receive_packets(struct uloop_fd *u, _unused unsigned int events)
327 struct odhcpd_event *e = container_of(u, struct odhcpd_event, uloop);
329 uint8_t data_buf[8192], cmsg_buf[128];
331 struct sockaddr_in6 in6;
332 struct sockaddr_in in;
333 struct sockaddr_ll ll;
334 struct sockaddr_nl nl;
339 socklen_t ret_len = sizeof(ret);
342 if (e->handle_error && getsockopt(u->fd, SOL_SOCKET, SO_ERROR, &ret, &ret_len) == 0)
343 e->handle_error(e, ret);
352 struct iovec iov = {data_buf, sizeof(data_buf)};
353 struct msghdr msg = {
354 .msg_name = (void *) &addr,
355 .msg_namelen = sizeof(addr),
358 .msg_control = cmsg_buf,
359 .msg_controllen = sizeof(cmsg_buf),
363 ssize_t len = recvmsg(u->fd, &msg, MSG_DONTWAIT);
372 /* Extract destination interface */
376 struct in6_pktinfo *pktinfo;
377 struct in_pktinfo *pkt4info;
378 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL; ch = CMSG_NXTHDR(&msg, ch)) {
379 if (ch->cmsg_level == IPPROTO_IPV6 &&
380 ch->cmsg_type == IPV6_PKTINFO) {
381 pktinfo = (struct in6_pktinfo*)CMSG_DATA(ch);
382 destiface = pktinfo->ipi6_ifindex;
383 dest = &pktinfo->ipi6_addr;
384 } else if (ch->cmsg_level == IPPROTO_IP &&
385 ch->cmsg_type == IP_PKTINFO) {
386 pkt4info = (struct in_pktinfo*)CMSG_DATA(ch);
387 destiface = pkt4info->ipi_ifindex;
388 dest = &pkt4info->ipi_addr;
389 } else if (ch->cmsg_level == IPPROTO_IPV6 &&
390 ch->cmsg_type == IPV6_HOPLIMIT) {
391 hlim = (int*)CMSG_DATA(ch);
395 /* Check hoplimit if received */
396 if (hlim && *hlim != 255)
399 /* Detect interface for packet sockets */
400 if (addr.ll.sll_family == AF_PACKET)
401 destiface = addr.ll.sll_ifindex;
403 char ipbuf[INET6_ADDRSTRLEN] = "kernel";
404 if (addr.ll.sll_family == AF_PACKET &&
405 len >= (ssize_t)sizeof(struct ip6_hdr))
406 inet_ntop(AF_INET6, &data_buf[8], ipbuf, sizeof(ipbuf));
407 else if (addr.in6.sin6_family == AF_INET6)
408 inet_ntop(AF_INET6, &addr.in6.sin6_addr, ipbuf, sizeof(ipbuf));
409 else if (addr.in.sin_family == AF_INET)
410 inet_ntop(AF_INET, &addr.in.sin_addr, ipbuf, sizeof(ipbuf));
413 if (addr.nl.nl_family == AF_NETLINK) {
414 syslog(LOG_DEBUG, "Received %li Bytes from %s%%%s", (long)len,
416 e->handle_dgram(&addr, data_buf, len, NULL, dest);
418 } else if (destiface != 0) {
419 struct interface *iface;
420 list_for_each_entry(iface, &interfaces, head) {
421 if (iface->ifindex != destiface)
424 syslog(LOG_DEBUG, "Received %li Bytes from %s%%%s", (long)len,
425 ipbuf, iface->ifname);
427 e->handle_dgram(&addr, data_buf, len, iface, dest);
435 /* Register events for the multiplexer */
436 int odhcpd_register(struct odhcpd_event *event)
438 event->uloop.cb = odhcpd_receive_packets;
439 return uloop_fd_add(&event->uloop, ULOOP_READ |
440 ((event->handle_error) ? ULOOP_ERROR_CB : 0));
443 int odhcpd_deregister(struct odhcpd_event *event)
445 event->uloop.cb = NULL;
446 return uloop_fd_delete(&event->uloop);
449 void odhcpd_process(struct odhcpd_event *event)
451 odhcpd_receive_packets(&event->uloop, 0);
454 int odhcpd_urandom(void *data, size_t len)
456 return read(urandom_fd, data, len);
460 time_t odhcpd_time(void)
463 syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &ts);
468 static const char hexdigits[] = "0123456789abcdef";
469 static const int8_t hexvals[] = {
470 -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
471 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
472 -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
473 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
474 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
475 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
476 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
477 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
480 ssize_t odhcpd_unhexlify(uint8_t *dst, size_t len, const char *src)
483 for (c = 0; c < len && src[0] && src[1]; ++c) {
484 int8_t x = (int8_t)*src++;
485 int8_t y = (int8_t)*src++;
486 if (x < 0 || (x = hexvals[x]) < 0
487 || y < 0 || (y = hexvals[y]) < 0)
490 while (((int8_t)*src) < 0 ||
491 (*src && hexvals[(uint8_t)*src] < 0))
499 void odhcpd_hexlify(char *dst, const uint8_t *src, size_t len)
501 for (size_t i = 0; i < len; ++i) {
502 *dst++ = hexdigits[src[i] >> 4];
503 *dst++ = hexdigits[src[i] & 0x0f];
508 const char *odhcpd_print_mac(const uint8_t *mac, const size_t len)
512 snprintf(buf, sizeof(buf), "%02x", mac[0]);
513 for (size_t i = 1, j = 2; i < len && j < sizeof(buf); i++, j += 3)
514 snprintf(buf + j, sizeof(buf) - j, ":%02x", mac[i]);
519 int odhcpd_bmemcmp(const void *av, const void *bv, size_t bits)
521 const uint8_t *a = av, *b = bv;
522 size_t bytes = bits / 8;
525 int res = memcmp(a, b, bytes);
526 if (res == 0 && bits > 0)
527 res = (a[bytes] >> (8 - bits)) - (b[bytes] >> (8 - bits));
533 void odhcpd_bmemcpy(void *av, const void *bv, size_t bits)
536 const uint8_t *b = bv;
538 size_t bytes = bits / 8;
543 uint8_t mask = (1 << (8 - bits)) - 1;
544 a[bytes] = (a[bytes] & mask) | ((~mask) & b[bytes]);
549 int odhcpd_netmask2bitlen(bool inet6, void *mask)
556 for (bits = 0, v6 = mask;
557 bits < 128 && (v6->s6_addr[bits / 8] << (bits % 8)) & 128;
560 for (bits = 0, v4 = mask;
561 bits < 32 && (ntohl(v4->s_addr) << bits) & 0x80000000;
567 bool odhcpd_bitlen2netmask(bool inet6, unsigned int bits, void *mask)
580 for (unsigned int i = 0; i < sizeof(v6->s6_addr); i++)
582 b = (bits > 8) ? 8 : bits;
583 v6->s6_addr[i] = (uint8_t)(0xFF << (8 - b));
593 v4->s_addr = bits ? htonl(~((1 << (32 - bits)) - 1)) : 0;
599 bool odhcpd_valid_hostname(const char *name)
602 const char *c, *label, *label_end;
605 for (c = name, label_sz = 0, label = name, label_end = name + strcspn(name, ".") - 1;
606 *c && label_sz <= MAX_LABEL; c++) {
607 if ((*c >= '0' && *c <= '9') ||
608 (*c >= 'A' && *c <= 'Z') ||
609 (*c >= 'a' && *c <= 'z')) {
614 if ((*c == '_' || *c == '-') && c != label && c != label_end) {
622 label_end = label + strcspn(label, ".") - 1;
631 return (label_sz && label_sz <= MAX_LABEL ? true : false);