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/netlink.h>
33 #include <linux/rtnetlink.h>
35 #include <sys/socket.h>
36 #include <sys/ioctl.h>
37 #include <sys/epoll.h>
38 #include <sys/types.h>
40 #include <sys/syscall.h>
42 #include <libubox/uloop.h>
47 static int ioctl_sock;
48 static int rtnl_socket = -1;
49 static int rtnl_seq = 0;
50 static int urandom_fd = -1;
53 static void sighandler(_unused int signal)
58 static void print_usage(const char *app)
62 " -h, --help Print this help\n"
63 " -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);
72 int log_level = LOG_WARNING;
73 while ((opt = getopt(argc, argv, "hl:")) != -1) {
79 log_level = atoi(optarg);
80 fprintf(stderr, "Log level set to %d\n", log_level);
84 setlogmask(LOG_UPTO(log_level));
88 syslog(LOG_ERR, "Must be run as root!");
92 ioctl_sock = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
94 if ((rtnl_socket = odhcpd_open_rtnl()) < 0) {
95 syslog(LOG_ERR, "Unable to open socket: %s", strerror(errno));
99 if ((urandom_fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC)) < 0)
102 signal(SIGUSR1, SIG_IGN);
103 signal(SIGINT, sighandler);
104 signal(SIGTERM, sighandler);
122 int odhcpd_open_rtnl(void)
124 int sock = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, NETLINK_ROUTE);
126 // Connect to the kernel netlink interface
127 struct sockaddr_nl nl = {.nl_family = AF_NETLINK};
128 if (connect(sock, (struct sockaddr*)&nl, sizeof(nl))) {
129 syslog(LOG_ERR, "Failed to connect to kernel rtnetlink: %s",
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);
146 ssize_t len = read(fd, buf, sizeof(buf) - 1);
157 // Read IPv6 MAC for interface
158 int odhcpd_get_mac(const struct interface *iface, uint8_t mac[6])
161 memset(&ifr, 0, sizeof(ifr));
162 strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name));
163 if (ioctl(ioctl_sock, SIOCGIFHWADDR, &ifr) < 0)
165 memcpy(mac, ifr.ifr_hwaddr.sa_data, 6);
170 // Forwards a packet on a specific interface
171 ssize_t odhcpd_send(int socket, struct sockaddr_in6 *dest,
172 struct iovec *iov, size_t iov_len,
173 const struct interface *iface)
176 uint8_t cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))] = {0};
177 struct msghdr msg = {
178 .msg_name = (void *) dest,
179 .msg_namelen = sizeof(*dest),
181 .msg_iovlen = iov_len,
182 .msg_control = cmsg_buf,
183 .msg_controllen = sizeof(cmsg_buf),
187 // Set control data (define destination interface)
188 struct cmsghdr *chdr = CMSG_FIRSTHDR(&msg);
189 chdr->cmsg_level = IPPROTO_IPV6;
190 chdr->cmsg_type = IPV6_PKTINFO;
191 chdr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
192 struct in6_pktinfo *pktinfo = (struct in6_pktinfo*)CMSG_DATA(chdr);
193 pktinfo->ipi6_ifindex = iface->ifindex;
195 // Also set scope ID if link-local
196 if (IN6_IS_ADDR_LINKLOCAL(&dest->sin6_addr)
197 || IN6_IS_ADDR_MC_LINKLOCAL(&dest->sin6_addr))
198 dest->sin6_scope_id = iface->ifindex;
200 char ipbuf[INET6_ADDRSTRLEN];
201 inet_ntop(AF_INET6, &dest->sin6_addr, ipbuf, sizeof(ipbuf));
203 ssize_t sent = sendmsg(socket, &msg, MSG_DONTWAIT);
205 syslog(LOG_NOTICE, "Failed to send to %s%%%s (%s)",
206 ipbuf, iface->ifname, strerror(errno));
208 syslog(LOG_DEBUG, "Sent %li bytes to %s%%%s",
209 (long)sent, ipbuf, iface->ifname);
214 // Detect an IPV6-address currently assigned to the given interface
215 ssize_t odhcpd_get_interface_addresses(int ifindex,
216 struct odhcpd_ipaddr *addrs, size_t cnt)
220 struct ifaddrmsg ifa;
221 } req = {{sizeof(req), RTM_GETADDR, NLM_F_REQUEST | NLM_F_DUMP,
222 ++rtnl_seq, 0}, {AF_INET6, 0, 0, 0, ifindex}};
223 if (send(rtnl_socket, &req, sizeof(req), 0) < (ssize_t)sizeof(req)) {
224 syslog(LOG_WARNING, "Request failed to dump IPv6 addresses (%s)", strerror(errno));
229 ssize_t len = 0, ret = 0;
231 for (struct nlmsghdr *nhm = NULL; ; nhm = NLMSG_NEXT(nhm, len)) {
232 while (len < 0 || !NLMSG_OK(nhm, (size_t)len)) {
233 len = recv(rtnl_socket, buf, sizeof(buf), 0);
234 nhm = (struct nlmsghdr*)buf;
235 if (len < 0 || !NLMSG_OK(nhm, (size_t)len)) {
239 syslog(LOG_WARNING, "Failed to receive IPv6 address rtnetlink message (%s)", strerror(errno));
245 switch (nhm->nlmsg_type) {
247 // Skip address but keep clearing socket buffer
248 if (ret >= (ssize_t)cnt)
251 struct ifaddrmsg *ifa = NLMSG_DATA(nhm);
252 if (ifa->ifa_scope != RT_SCOPE_UNIVERSE ||
253 (ifindex && ifa->ifa_index != (unsigned)ifindex))
256 struct rtattr *rta = (struct rtattr*)&ifa[1];
257 size_t alen = NLMSG_PAYLOAD(nhm, sizeof(*ifa));
258 memset(&addrs[ret], 0, sizeof(addrs[ret]));
259 addrs[ret].prefix = ifa->ifa_prefixlen;
261 while (RTA_OK(rta, alen)) {
262 if (rta->rta_type == IFA_ADDRESS) {
263 memcpy(&addrs[ret].addr, RTA_DATA(rta),
264 sizeof(struct in6_addr));
265 } else if (rta->rta_type == IFA_CACHEINFO) {
266 struct ifa_cacheinfo *ifc = RTA_DATA(rta);
267 addrs[ret].preferred = ifc->ifa_prefered;
268 addrs[ret].valid = ifc->ifa_valid;
271 rta = RTA_NEXT(rta, alen);
274 if (ifa->ifa_flags & IFA_F_DEPRECATED)
275 addrs[ret].preferred = 0;
283 syslog(LOG_WARNING, "Unexpected rtnetlink message (%d) in response to IPv6 address dump", nhm->nlmsg_type);
293 int odhcpd_get_linklocal_interface_address(int ifindex, struct in6_addr *lladdr)
296 struct sockaddr_in6 addr = {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, ifindex};
297 socklen_t alen = sizeof(addr);
298 int sock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
300 if (!connect(sock, (struct sockaddr*)&addr, sizeof(addr)) &&
301 !getsockname(sock, (struct sockaddr*)&addr, &alen)) {
302 *lladdr = addr.sin6_addr;
310 void odhcpd_setup_route(const struct in6_addr *addr, int prefixlen,
311 const struct interface *iface, const struct in6_addr *gw,
312 int metric, bool add)
317 struct rtattr rta_dst;
318 struct in6_addr dst_addr;
319 struct rtattr rta_oif;
321 struct rtattr rta_table;
323 struct rtattr rta_prio;
325 struct rtattr rta_gw;
328 {sizeof(req), 0, NLM_F_REQUEST, ++rtnl_seq, 0},
329 {AF_INET6, prefixlen, 0, 0, 0, 0, 0, 0, 0},
330 {sizeof(struct rtattr) + sizeof(struct in6_addr), RTA_DST},
332 {sizeof(struct rtattr) + sizeof(uint32_t), RTA_OIF},
334 {sizeof(struct rtattr) + sizeof(uint32_t), RTA_TABLE},
336 {sizeof(struct rtattr) + sizeof(uint32_t), RTA_PRIORITY},
338 {sizeof(struct rtattr) + sizeof(struct in6_addr), RTA_GATEWAY},
346 req.nh.nlmsg_type = RTM_NEWROUTE;
347 req.nh.nlmsg_flags |= (NLM_F_CREATE | NLM_F_REPLACE);
348 req.rtm.rtm_protocol = RTPROT_STATIC;
349 req.rtm.rtm_scope = (gw) ? RT_SCOPE_UNIVERSE : RT_SCOPE_LINK;
350 req.rtm.rtm_type = RTN_UNICAST;
352 req.nh.nlmsg_type = RTM_DELROUTE;
353 req.rtm.rtm_scope = RT_SCOPE_NOWHERE;
356 req.nh.nlmsg_len = (gw) ? sizeof(req) : offsetof(struct req, rta_gw);
357 send(rtnl_socket, &req, req.nh.nlmsg_len, MSG_DONTWAIT);
360 struct interface* odhcpd_get_interface_by_index(int ifindex)
362 struct interface *iface;
363 list_for_each_entry(iface, &interfaces, head)
364 if (iface->ifindex == ifindex)
371 struct interface* odhcpd_get_interface_by_name(const char *name)
373 struct interface *iface;
374 list_for_each_entry(iface, &interfaces, head)
375 if (!strcmp(iface->ifname, name))
382 struct interface* odhcpd_get_master_interface(void)
384 struct interface *iface;
385 list_for_each_entry(iface, &interfaces, head)
393 // Convenience function to receive and do basic validation of packets
394 static void odhcpd_receive_packets(struct uloop_fd *u, _unused unsigned int events)
396 struct odhcpd_event *e = container_of(u, struct odhcpd_event, uloop);
398 uint8_t data_buf[RELAYD_BUFFER_SIZE], cmsg_buf[128];
400 struct sockaddr_in6 in6;
401 struct sockaddr_in in;
402 struct sockaddr_ll ll;
403 struct sockaddr_nl nl;
408 socklen_t ret_len = sizeof(ret);
409 getsockopt(u->fd, SOL_SOCKET, SO_ERROR, &ret, &ret_len);
412 e->handle_error(ret);
416 struct iovec iov = {data_buf, sizeof(data_buf)};
417 struct msghdr msg = {
418 .msg_name = (void *) &addr,
419 .msg_namelen = sizeof(addr),
422 .msg_control = cmsg_buf,
423 .msg_controllen = sizeof(cmsg_buf),
427 ssize_t len = recvmsg(u->fd, &msg, MSG_DONTWAIT);
436 // Extract destination interface
440 struct in6_pktinfo *pktinfo;
441 struct in_pktinfo *pkt4info;
442 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL; ch = CMSG_NXTHDR(&msg, ch)) {
443 if (ch->cmsg_level == IPPROTO_IPV6 &&
444 ch->cmsg_type == IPV6_PKTINFO) {
445 pktinfo = (struct in6_pktinfo*)CMSG_DATA(ch);
446 destiface = pktinfo->ipi6_ifindex;
447 dest = &pktinfo->ipi6_addr;
448 } else if (ch->cmsg_level == IPPROTO_IP &&
449 ch->cmsg_type == IP_PKTINFO) {
450 pkt4info = (struct in_pktinfo*)CMSG_DATA(ch);
451 destiface = pkt4info->ipi_ifindex;
452 dest = &pkt4info->ipi_addr;
453 } else if (ch->cmsg_level == IPPROTO_IPV6 &&
454 ch->cmsg_type == IPV6_HOPLIMIT) {
455 hlim = (int*)CMSG_DATA(ch);
459 // Check hoplimit if received
460 if (hlim && *hlim != 255)
463 // Detect interface for packet sockets
464 if (addr.ll.sll_family == AF_PACKET)
465 destiface = addr.ll.sll_ifindex;
467 struct interface *iface =
468 odhcpd_get_interface_by_index(destiface);
470 if (!iface && addr.nl.nl_family != AF_NETLINK)
473 char ipbuf[INET6_ADDRSTRLEN] = "kernel";
474 if (addr.ll.sll_family == AF_PACKET &&
475 len >= (ssize_t)sizeof(struct ip6_hdr))
476 inet_ntop(AF_INET6, &data_buf[8], ipbuf, sizeof(ipbuf));
477 else if (addr.in6.sin6_family == AF_INET6)
478 inet_ntop(AF_INET6, &addr.in6.sin6_addr, ipbuf, sizeof(ipbuf));
479 else if (addr.in.sin_family == AF_INET)
480 inet_ntop(AF_INET, &addr.in.sin_addr, ipbuf, sizeof(ipbuf));
482 syslog(LOG_DEBUG, "Received %li Bytes from %s%%%s", (long)len,
483 ipbuf, (iface) ? iface->ifname : "netlink");
485 e->handle_dgram(&addr, data_buf, len, iface, dest);
489 // Register events for the multiplexer
490 int odhcpd_register(struct odhcpd_event *event)
492 event->uloop.cb = odhcpd_receive_packets;
493 return uloop_fd_add(&event->uloop, ULOOP_READ |
494 ((event->handle_error) ? ULOOP_ERROR_CB : 0));
497 void odhcpd_process(struct odhcpd_event *event)
499 odhcpd_receive_packets(&event->uloop, 0);
502 int odhcpd_urandom(void *data, size_t len)
504 return read(urandom_fd, data, len);
508 time_t odhcpd_time(void)
511 syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &ts);
516 static const char hexdigits[] = "0123456789abcdef";
517 static const int8_t hexvals[] = {
518 -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
519 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
520 -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
521 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
522 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
523 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
524 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
525 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
528 ssize_t odhcpd_unhexlify(uint8_t *dst, size_t len, const char *src)
531 for (c = 0; c < len && src[0] && src[1]; ++c) {
532 int8_t x = (int8_t)*src++;
533 int8_t y = (int8_t)*src++;
534 if (x < 0 || (x = hexvals[x]) < 0
535 || y < 0 || (y = hexvals[y]) < 0)
538 while (((int8_t)*src) < 0 ||
539 (*src && hexvals[(uint8_t)*src] < 0))
547 void odhcpd_hexlify(char *dst, const uint8_t *src, size_t len)
549 for (size_t i = 0; i < len; ++i) {
550 *dst++ = hexdigits[src[i] >> 4];
551 *dst++ = hexdigits[src[i] & 0x0f];
557 int odhcpd_bmemcmp(const void *av, const void *bv, size_t bits)
559 const uint8_t *a = av, *b = bv;
560 size_t bytes = bits / 8;
563 int res = memcmp(a, b, bytes);
564 if (res == 0 && bits > 0)
565 res = (a[bytes] >> (8 - bits)) - (b[bytes] >> (8 - bits));
571 void odhcpd_bmemcpy(void *av, const void *bv, size_t bits)
574 const uint8_t *b = bv;
576 size_t bytes = bits / 8;
581 uint8_t mask = (1 << (8 - bits)) - 1;
582 a[bytes] = (a[bytes] & mask) | ((~mask) & b[bytes]);