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>
46 static int ioctl_sock = -1;
47 static int urandom_fd = -1;
49 static void sighandler(_unused int signal)
54 static void print_usage(const char *app)
58 " -h, --help Print this help\n"
59 " -l level Specify log level 0..7 (default %d)\n",
64 static bool ipv6_enabled(void)
66 int fd = socket(AF_INET6, SOCK_DGRAM, 0);
76 int main(int argc, char **argv)
78 openlog("odhcpd", LOG_PERROR | LOG_PID, LOG_DAEMON);
81 while ((opt = getopt(argc, argv, "hl:")) != -1) {
87 config.log_level = (atoi(optarg) & LOG_PRIMASK);
88 fprintf(stderr, "Log level set to %d\n", config.log_level);
92 setlogmask(LOG_UPTO(config.log_level));
96 syslog(LOG_ERR, "Must be run as root!");
100 ioctl_sock = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
105 if ((urandom_fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC)) < 0)
108 signal(SIGUSR1, SIG_IGN);
109 signal(SIGINT, sighandler);
110 signal(SIGTERM, sighandler);
115 if (ipv6_enabled()) {
125 #ifndef DHCPV4_SUPPORT
138 /* Read IPv6 MTU for interface */
139 int odhcpd_get_interface_config(const char *ifname, const char *what)
142 const char *sysctl_pattern = "/proc/sys/net/ipv6/conf/%s/%s";
143 snprintf(buf, sizeof(buf), sysctl_pattern, ifname, what);
145 int fd = open(buf, O_RDONLY);
149 ssize_t len = read(fd, buf, sizeof(buf) - 1);
160 /* Read IPv6 MAC for interface */
161 int odhcpd_get_mac(const struct interface *iface, uint8_t mac[6])
165 memset(&ifr, 0, sizeof(ifr));
166 strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name) - 1);
167 if (ioctl(ioctl_sock, SIOCGIFHWADDR, &ifr) < 0)
170 memcpy(mac, ifr.ifr_hwaddr.sa_data, 6);
175 /* Forwards a packet on a specific interface */
176 ssize_t odhcpd_send(int socket, struct sockaddr_in6 *dest,
177 struct iovec *iov, size_t iov_len,
178 const struct interface *iface)
180 /* Construct headers */
181 uint8_t cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))] = {0};
182 struct msghdr msg = {
183 .msg_name = (void *) dest,
184 .msg_namelen = sizeof(*dest),
186 .msg_iovlen = iov_len,
187 .msg_control = cmsg_buf,
188 .msg_controllen = sizeof(cmsg_buf),
192 /* Set control data (define destination interface) */
193 struct cmsghdr *chdr = CMSG_FIRSTHDR(&msg);
194 chdr->cmsg_level = IPPROTO_IPV6;
195 chdr->cmsg_type = IPV6_PKTINFO;
196 chdr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
197 struct in6_pktinfo *pktinfo = (struct in6_pktinfo*)CMSG_DATA(chdr);
198 pktinfo->ipi6_ifindex = iface->ifindex;
200 /* Also set scope ID if link-local */
201 if (IN6_IS_ADDR_LINKLOCAL(&dest->sin6_addr)
202 || IN6_IS_ADDR_MC_LINKLOCAL(&dest->sin6_addr))
203 dest->sin6_scope_id = iface->ifindex;
205 char ipbuf[INET6_ADDRSTRLEN];
206 inet_ntop(AF_INET6, &dest->sin6_addr, ipbuf, sizeof(ipbuf));
208 ssize_t sent = sendmsg(socket, &msg, MSG_DONTWAIT);
210 syslog(LOG_ERR, "Failed to send to %s%%%s@%s (%m)",
211 ipbuf, iface->name, iface->ifname);
213 syslog(LOG_DEBUG, "Sent %zd bytes to %s%%%s@%s",
214 sent, ipbuf, iface->name, iface->ifname);
219 static int odhcpd_get_linklocal_interface_address(int ifindex, struct in6_addr *lladdr)
222 struct sockaddr_in6 addr;
223 socklen_t alen = sizeof(addr);
224 int sock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
229 memset(&addr, 0, sizeof(addr));
230 addr.sin6_family = AF_INET6;
231 inet_pton(AF_INET6, ALL_IPV6_ROUTERS, &addr.sin6_addr);
232 addr.sin6_scope_id = ifindex;
234 if (!connect(sock, (struct sockaddr*)&addr, sizeof(addr)) &&
235 !getsockname(sock, (struct sockaddr*)&addr, &alen)) {
236 *lladdr = addr.sin6_addr;
245 * DNS address selection criteria order :
246 * - use IPv6 address with valid lifetime if none is yet selected
247 * - use IPv6 address with a preferred lifetime if the already selected IPv6 address is deprecated
248 * - use an IPv6 ULA address if the already selected IPv6 address is not an ULA address
249 * - use the IPv6 address with the longest preferred lifetime
251 int odhcpd_get_interface_dns_addr(const struct interface *iface, struct in6_addr *addr)
253 time_t now = odhcpd_time();
256 for (size_t i = 0; i < iface->addr6_len; ++i) {
257 if (iface->addr6[i].valid <= (uint32_t)now)
265 if (iface->addr6[m].preferred >= (uint32_t)now &&
266 iface->addr6[i].preferred < (uint32_t)now)
269 if (IN6_IS_ADDR_ULA(&iface->addr6[i].addr.in6)) {
270 if (!IN6_IS_ADDR_ULA(&iface->addr6[m].addr.in6)) {
274 } else if (IN6_IS_ADDR_ULA(&iface->addr6[m].addr.in6))
277 if (iface->addr6[i].preferred > iface->addr6[m].preferred)
282 *addr = iface->addr6[m].addr.in6;
286 return odhcpd_get_linklocal_interface_address(iface->ifindex, addr);
289 struct interface* odhcpd_get_interface_by_index(int ifindex)
291 struct interface *iface;
293 avl_for_each_element(&interfaces, iface, avl) {
294 if (iface->ifindex == ifindex)
301 /* Convenience function to receive and do basic validation of packets */
302 static void odhcpd_receive_packets(struct uloop_fd *u, _unused unsigned int events)
304 struct odhcpd_event *e = container_of(u, struct odhcpd_event, uloop);
306 uint8_t data_buf[8192], cmsg_buf[128];
308 struct sockaddr_in6 in6;
309 struct sockaddr_in in;
310 struct sockaddr_ll ll;
311 struct sockaddr_nl nl;
316 socklen_t ret_len = sizeof(ret);
319 if (e->handle_error && getsockopt(u->fd, SOL_SOCKET, SO_ERROR, &ret, &ret_len) == 0)
320 e->handle_error(e, ret);
329 struct iovec iov = {data_buf, sizeof(data_buf)};
330 struct msghdr msg = {
331 .msg_name = (void *) &addr,
332 .msg_namelen = sizeof(addr),
335 .msg_control = cmsg_buf,
336 .msg_controllen = sizeof(cmsg_buf),
340 ssize_t len = recvmsg(u->fd, &msg, MSG_DONTWAIT);
349 /* Extract destination interface */
353 struct in6_pktinfo *pktinfo;
354 struct in_pktinfo *pkt4info;
355 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL; ch = CMSG_NXTHDR(&msg, ch)) {
356 if (ch->cmsg_level == IPPROTO_IPV6 &&
357 ch->cmsg_type == IPV6_PKTINFO) {
358 pktinfo = (struct in6_pktinfo*)CMSG_DATA(ch);
359 destiface = pktinfo->ipi6_ifindex;
360 dest = &pktinfo->ipi6_addr;
361 } else if (ch->cmsg_level == IPPROTO_IP &&
362 ch->cmsg_type == IP_PKTINFO) {
363 pkt4info = (struct in_pktinfo*)CMSG_DATA(ch);
364 destiface = pkt4info->ipi_ifindex;
365 dest = &pkt4info->ipi_addr;
366 } else if (ch->cmsg_level == IPPROTO_IPV6 &&
367 ch->cmsg_type == IPV6_HOPLIMIT) {
368 hlim = (int*)CMSG_DATA(ch);
372 /* Check hoplimit if received */
373 if (hlim && *hlim != 255)
376 /* Detect interface for packet sockets */
377 if (addr.ll.sll_family == AF_PACKET)
378 destiface = addr.ll.sll_ifindex;
380 char ipbuf[INET6_ADDRSTRLEN] = "kernel";
381 if (addr.ll.sll_family == AF_PACKET &&
382 len >= (ssize_t)sizeof(struct ip6_hdr))
383 inet_ntop(AF_INET6, &data_buf[8], ipbuf, sizeof(ipbuf));
384 else if (addr.in6.sin6_family == AF_INET6)
385 inet_ntop(AF_INET6, &addr.in6.sin6_addr, ipbuf, sizeof(ipbuf));
386 else if (addr.in.sin_family == AF_INET)
387 inet_ntop(AF_INET, &addr.in.sin_addr, ipbuf, sizeof(ipbuf));
390 if (addr.nl.nl_family == AF_NETLINK) {
391 syslog(LOG_DEBUG, "Received %zd Bytes from %s%%netlink", len,
393 e->handle_dgram(&addr, data_buf, len, NULL, dest);
395 } else if (destiface != 0) {
396 struct interface *iface;
398 avl_for_each_element(&interfaces, iface, avl) {
399 if (iface->ifindex != destiface)
402 syslog(LOG_DEBUG, "Received %zd Bytes from %s%%%s@%s", len,
403 ipbuf, iface->name, iface->ifname);
405 e->handle_dgram(&addr, data_buf, len, iface, dest);
413 /* Register events for the multiplexer */
414 int odhcpd_register(struct odhcpd_event *event)
416 event->uloop.cb = odhcpd_receive_packets;
417 return uloop_fd_add(&event->uloop, ULOOP_READ |
418 ((event->handle_error) ? ULOOP_ERROR_CB : 0));
421 int odhcpd_deregister(struct odhcpd_event *event)
423 event->uloop.cb = NULL;
424 return uloop_fd_delete(&event->uloop);
427 void odhcpd_process(struct odhcpd_event *event)
429 odhcpd_receive_packets(&event->uloop, 0);
432 int odhcpd_urandom(void *data, size_t len)
434 return read(urandom_fd, data, len);
438 time_t odhcpd_time(void)
441 clock_gettime(CLOCK_MONOTONIC, &ts);
446 static const char hexdigits[] = "0123456789abcdef";
447 static const int8_t hexvals[] = {
448 -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
449 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
450 -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
451 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
452 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
453 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
454 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
455 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
458 ssize_t odhcpd_unhexlify(uint8_t *dst, size_t len, const char *src)
461 for (c = 0; c < len && src[0] && src[1]; ++c) {
462 int8_t x = (int8_t)*src++;
463 int8_t y = (int8_t)*src++;
464 if (x < 0 || (x = hexvals[x]) < 0
465 || y < 0 || (y = hexvals[y]) < 0)
468 while (((int8_t)*src) < 0 ||
469 (*src && hexvals[(uint8_t)*src] < 0))
477 void odhcpd_hexlify(char *dst, const uint8_t *src, size_t len)
479 for (size_t i = 0; i < len; ++i) {
480 *dst++ = hexdigits[src[i] >> 4];
481 *dst++ = hexdigits[src[i] & 0x0f];
486 const char *odhcpd_print_mac(const uint8_t *mac, const size_t len)
490 snprintf(buf, sizeof(buf), "%02x", mac[0]);
491 for (size_t i = 1, j = 2; i < len && j < sizeof(buf); i++, j += 3)
492 snprintf(buf + j, sizeof(buf) - j, ":%02x", mac[i]);
497 int odhcpd_bmemcmp(const void *av, const void *bv, size_t bits)
499 const uint8_t *a = av, *b = bv;
500 size_t bytes = bits / 8;
503 int res = memcmp(a, b, bytes);
504 if (res == 0 && bits > 0)
505 res = (a[bytes] >> (8 - bits)) - (b[bytes] >> (8 - bits));
511 void odhcpd_bmemcpy(void *av, const void *bv, size_t bits)
514 const uint8_t *b = bv;
516 size_t bytes = bits / 8;
521 uint8_t mask = (1 << (8 - bits)) - 1;
522 a[bytes] = (a[bytes] & mask) | ((~mask) & b[bytes]);
527 int odhcpd_netmask2bitlen(bool inet6, void *mask)
534 for (bits = 0, v6 = mask;
535 bits < 128 && (v6->s6_addr[bits / 8] << (bits % 8)) & 128;
538 for (bits = 0, v4 = mask;
539 bits < 32 && (ntohl(v4->s_addr) << bits) & 0x80000000;
545 bool odhcpd_bitlen2netmask(bool inet6, unsigned int bits, void *mask)
558 for (unsigned int i = 0; i < sizeof(v6->s6_addr); i++)
560 b = (bits > 8) ? 8 : bits;
561 v6->s6_addr[i] = (uint8_t)(0xFF << (8 - b));
571 v4->s_addr = bits ? htonl(~((1 << (32 - bits)) - 1)) : 0;
577 bool odhcpd_valid_hostname(const char *name)
580 const char *c, *label, *label_end;
583 for (c = name, label_sz = 0, label = name, label_end = name + strcspn(name, ".") - 1;
584 *c && label_sz <= MAX_LABEL; c++) {
585 if ((*c >= '0' && *c <= '9') ||
586 (*c >= 'A' && *c <= 'Z') ||
587 (*c >= 'a' && *c <= 'z')) {
592 if ((*c == '_' || *c == '-') && c != label && c != label_end) {
600 label_end = label + strcspn(label, ".") - 1;
609 return (label_sz && label_sz <= MAX_LABEL ? true : false);