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)
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",
68 int main(int argc, char **argv)
70 openlog("odhcpd", LOG_PERROR | LOG_PID, LOG_DAEMON);
73 while ((opt = getopt(argc, argv, "hl:")) != -1) {
79 config.log_level = (atoi(optarg) & LOG_PRIMASK);
80 fprintf(stderr, "Log level set to %d\n", config.log_level);
84 setlogmask(LOG_UPTO(config.log_level));
88 syslog(LOG_ERR, "Must be run as root!");
92 ioctl_sock = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
94 if ((urandom_fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC)) < 0)
97 signal(SIGUSR1, SIG_IGN);
98 signal(SIGINT, sighandler);
99 signal(SIGTERM, sighandler);
113 #ifdef DHCPV4_SUPPORT
123 // Read IPv6 MTU for interface
124 int odhcpd_get_interface_config(const char *ifname, const char *what)
127 const char *sysctl_pattern = "/proc/sys/net/ipv6/conf/%s/%s";
128 snprintf(buf, sizeof(buf), sysctl_pattern, ifname, what);
130 int fd = open(buf, O_RDONLY);
131 ssize_t len = read(fd, buf, sizeof(buf) - 1);
142 // Read IPv6 MAC for interface
143 int odhcpd_get_mac(const struct interface *iface, uint8_t mac[6])
146 memset(&ifr, 0, sizeof(ifr));
147 strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name));
148 if (ioctl(ioctl_sock, SIOCGIFHWADDR, &ifr) < 0)
150 memcpy(mac, ifr.ifr_hwaddr.sa_data, 6);
155 // Forwards a packet on a specific interface
156 ssize_t odhcpd_send(int socket, struct sockaddr_in6 *dest,
157 struct iovec *iov, size_t iov_len,
158 const struct interface *iface)
161 uint8_t cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))] = {0};
162 struct msghdr msg = {
163 .msg_name = (void *) dest,
164 .msg_namelen = sizeof(*dest),
166 .msg_iovlen = iov_len,
167 .msg_control = cmsg_buf,
168 .msg_controllen = sizeof(cmsg_buf),
172 // Set control data (define destination interface)
173 struct cmsghdr *chdr = CMSG_FIRSTHDR(&msg);
174 chdr->cmsg_level = IPPROTO_IPV6;
175 chdr->cmsg_type = IPV6_PKTINFO;
176 chdr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
177 struct in6_pktinfo *pktinfo = (struct in6_pktinfo*)CMSG_DATA(chdr);
178 pktinfo->ipi6_ifindex = iface->ifindex;
180 // Also set scope ID if link-local
181 if (IN6_IS_ADDR_LINKLOCAL(&dest->sin6_addr)
182 || IN6_IS_ADDR_MC_LINKLOCAL(&dest->sin6_addr))
183 dest->sin6_scope_id = iface->ifindex;
185 char ipbuf[INET6_ADDRSTRLEN];
186 inet_ntop(AF_INET6, &dest->sin6_addr, ipbuf, sizeof(ipbuf));
188 ssize_t sent = sendmsg(socket, &msg, MSG_DONTWAIT);
190 syslog(LOG_NOTICE, "Failed to send to %s%%%s (%m)",
191 ipbuf, iface->ifname);
193 syslog(LOG_DEBUG, "Sent %li bytes to %s%%%s",
194 (long)sent, ipbuf, iface->ifname);
199 static int odhcpd_get_linklocal_interface_address(int ifindex, struct in6_addr *lladdr)
202 struct sockaddr_in6 addr = {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, ifindex};
203 socklen_t alen = sizeof(addr);
204 int sock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
206 if (!connect(sock, (struct sockaddr*)&addr, sizeof(addr)) &&
207 !getsockname(sock, (struct sockaddr*)&addr, &alen)) {
208 *lladdr = addr.sin6_addr;
218 * DNS address selection criteria order :
219 * - use IPv6 address with valid lifetime if none is yet selected
220 * - use IPv6 address with a preferred lifetime if the already selected IPv6 address is deprecated
221 * - use an IPv6 ULA address if the already selected IPv6 address is not an ULA address
222 * - use the IPv6 address with the longest preferred lifetime
224 int odhcpd_get_interface_dns_addr(const struct interface *iface, struct in6_addr *addr)
226 time_t now = odhcpd_time();
229 for (size_t i = 0; i < iface->addr6_len; ++i) {
230 if (iface->addr6[i].valid <= (uint32_t)now)
238 if (iface->addr6[m].preferred >= (uint32_t)now &&
239 iface->addr6[i].preferred < (uint32_t)now)
242 if (IN6_IS_ADDR_ULA(&iface->addr6[i].addr.in6)) {
243 if (!IN6_IS_ADDR_ULA(&iface->addr6[m].addr.in6)) {
247 } else if (IN6_IS_ADDR_ULA(&iface->addr6[m].addr.in6))
250 if (iface->addr6[i].preferred > iface->addr6[m].preferred)
255 *addr = iface->addr6[m].addr.in6;
259 return odhcpd_get_linklocal_interface_address(iface->ifindex, addr);
262 struct interface* odhcpd_get_interface_by_index(int ifindex)
264 struct interface *iface;
265 list_for_each_entry(iface, &interfaces, head)
266 if (iface->ifindex == ifindex)
273 struct interface* odhcpd_get_interface_by_name(const char *name)
275 struct interface *iface;
276 list_for_each_entry(iface, &interfaces, head)
277 if (!strcmp(iface->ifname, name))
284 struct interface* odhcpd_get_master_interface(void)
286 struct interface *iface;
287 list_for_each_entry(iface, &interfaces, head)
295 // Convenience function to receive and do basic validation of packets
296 static void odhcpd_receive_packets(struct uloop_fd *u, _unused unsigned int events)
298 struct odhcpd_event *e = container_of(u, struct odhcpd_event, uloop);
300 uint8_t data_buf[8192], cmsg_buf[128];
302 struct sockaddr_in6 in6;
303 struct sockaddr_in in;
304 struct sockaddr_ll ll;
305 struct sockaddr_nl nl;
310 socklen_t ret_len = sizeof(ret);
311 getsockopt(u->fd, SOL_SOCKET, SO_ERROR, &ret, &ret_len);
314 e->handle_error(e, ret);
323 struct iovec iov = {data_buf, sizeof(data_buf)};
324 struct msghdr msg = {
325 .msg_name = (void *) &addr,
326 .msg_namelen = sizeof(addr),
329 .msg_control = cmsg_buf,
330 .msg_controllen = sizeof(cmsg_buf),
334 ssize_t len = recvmsg(u->fd, &msg, MSG_DONTWAIT);
343 // Extract destination interface
347 struct in6_pktinfo *pktinfo;
348 struct in_pktinfo *pkt4info;
349 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL; ch = CMSG_NXTHDR(&msg, ch)) {
350 if (ch->cmsg_level == IPPROTO_IPV6 &&
351 ch->cmsg_type == IPV6_PKTINFO) {
352 pktinfo = (struct in6_pktinfo*)CMSG_DATA(ch);
353 destiface = pktinfo->ipi6_ifindex;
354 dest = &pktinfo->ipi6_addr;
355 } else if (ch->cmsg_level == IPPROTO_IP &&
356 ch->cmsg_type == IP_PKTINFO) {
357 pkt4info = (struct in_pktinfo*)CMSG_DATA(ch);
358 destiface = pkt4info->ipi_ifindex;
359 dest = &pkt4info->ipi_addr;
360 } else if (ch->cmsg_level == IPPROTO_IPV6 &&
361 ch->cmsg_type == IPV6_HOPLIMIT) {
362 hlim = (int*)CMSG_DATA(ch);
366 // Check hoplimit if received
367 if (hlim && *hlim != 255)
370 // Detect interface for packet sockets
371 if (addr.ll.sll_family == AF_PACKET)
372 destiface = addr.ll.sll_ifindex;
374 char ipbuf[INET6_ADDRSTRLEN] = "kernel";
375 if (addr.ll.sll_family == AF_PACKET &&
376 len >= (ssize_t)sizeof(struct ip6_hdr))
377 inet_ntop(AF_INET6, &data_buf[8], ipbuf, sizeof(ipbuf));
378 else if (addr.in6.sin6_family == AF_INET6)
379 inet_ntop(AF_INET6, &addr.in6.sin6_addr, ipbuf, sizeof(ipbuf));
380 else if (addr.in.sin_family == AF_INET)
381 inet_ntop(AF_INET, &addr.in.sin_addr, ipbuf, sizeof(ipbuf));
384 if (addr.nl.nl_family == AF_NETLINK) {
385 syslog(LOG_DEBUG, "Received %li Bytes from %s%%%s", (long)len,
387 e->handle_dgram(&addr, data_buf, len, NULL, dest);
389 } else if (destiface != 0) {
390 struct interface *iface;
391 list_for_each_entry(iface, &interfaces, head) {
392 if (iface->ifindex != destiface)
395 syslog(LOG_DEBUG, "Received %li Bytes from %s%%%s", (long)len,
396 ipbuf, iface->ifname);
398 e->handle_dgram(&addr, data_buf, len, iface, dest);
406 // Register events for the multiplexer
407 int odhcpd_register(struct odhcpd_event *event)
409 event->uloop.cb = odhcpd_receive_packets;
410 return uloop_fd_add(&event->uloop, ULOOP_READ |
411 ((event->handle_error) ? ULOOP_ERROR_CB : 0));
414 int odhcpd_deregister(struct odhcpd_event *event)
416 event->uloop.cb = NULL;
417 return uloop_fd_delete(&event->uloop);
420 void odhcpd_process(struct odhcpd_event *event)
422 odhcpd_receive_packets(&event->uloop, 0);
425 int odhcpd_urandom(void *data, size_t len)
427 return read(urandom_fd, data, len);
431 time_t odhcpd_time(void)
434 syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &ts);
439 static const char hexdigits[] = "0123456789abcdef";
440 static const int8_t hexvals[] = {
441 -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
442 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
443 -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
444 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
445 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
446 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
447 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
448 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
451 ssize_t odhcpd_unhexlify(uint8_t *dst, size_t len, const char *src)
454 for (c = 0; c < len && src[0] && src[1]; ++c) {
455 int8_t x = (int8_t)*src++;
456 int8_t y = (int8_t)*src++;
457 if (x < 0 || (x = hexvals[x]) < 0
458 || y < 0 || (y = hexvals[y]) < 0)
461 while (((int8_t)*src) < 0 ||
462 (*src && hexvals[(uint8_t)*src] < 0))
470 void odhcpd_hexlify(char *dst, const uint8_t *src, size_t len)
472 for (size_t i = 0; i < len; ++i) {
473 *dst++ = hexdigits[src[i] >> 4];
474 *dst++ = hexdigits[src[i] & 0x0f];
479 const char *odhcpd_print_mac(const uint8_t *mac, const size_t len)
483 snprintf(buf, sizeof(buf), "%02x", mac[0]);
484 for (size_t i = 1, j = 2; i < len && j < sizeof(buf); i++, j += 3)
485 snprintf(buf + j, sizeof(buf) - j, ":%02x", mac[i]);
490 int odhcpd_bmemcmp(const void *av, const void *bv, size_t bits)
492 const uint8_t *a = av, *b = bv;
493 size_t bytes = bits / 8;
496 int res = memcmp(a, b, bytes);
497 if (res == 0 && bits > 0)
498 res = (a[bytes] >> (8 - bits)) - (b[bytes] >> (8 - bits));
504 void odhcpd_bmemcpy(void *av, const void *bv, size_t bits)
507 const uint8_t *b = bv;
509 size_t bytes = bits / 8;
514 uint8_t mask = (1 << (8 - bits)) - 1;
515 a[bytes] = (a[bytes] & mask) | ((~mask) & b[bytes]);
520 int odhcpd_netmask2bitlen(bool inet6, void *mask)
527 for (bits = 0, v6 = mask;
528 bits < 128 && (v6->s6_addr[bits / 8] << (bits % 8)) & 128;
531 for (bits = 0, v4 = mask;
532 bits < 32 && (ntohl(v4->s_addr) << bits) & 0x80000000;
538 bool odhcpd_bitlen2netmask(bool inet6, unsigned int bits, void *mask)
551 for (unsigned int i = 0; i < sizeof(v6->s6_addr); i++)
553 b = (bits > 8) ? 8 : bits;
554 v6->s6_addr[i] = (uint8_t)(0xFF << (8 - b));
564 v4->s_addr = bits ? htonl(~((1 << (32 - bits)) - 1)) : 0;