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- /**
- * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License v2 as published by
- * the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- */
- #include <time.h>
- #include <errno.h>
- #include <fcntl.h>
- #include <stdio.h>
- #include <resolv.h>
- #include <getopt.h>
- #include <stddef.h>
- #include <stdlib.h>
- #include <string.h>
- #include <unistd.h>
- #include <signal.h>
- #include <stdbool.h>
- #include <syslog.h>
- #include <alloca.h>
- #include <arpa/inet.h>
- #include <net/if.h>
- #include <netinet/ip6.h>
- #include <netpacket/packet.h>
- #include <linux/netlink.h>
- #include <sys/socket.h>
- #include <sys/ioctl.h>
- #include <sys/epoll.h>
- #include <sys/types.h>
- #include <sys/wait.h>
- #include <sys/syscall.h>
- #include <libubox/uloop.h>
- #include "odhcpd.h"
- static int ioctl_sock = -1;
- static int urandom_fd = -1;
- static void sighandler(_unused int signal)
- {
- uloop_end();
- }
- static void print_usage(const char *app)
- {
- printf(
- "== %s Usage ==\n\n"
- " -h, --help Print this help\n"
- " -l level Specify log level 0..7 (default %d)\n",
- app, config.log_level
- );
- }
- static bool ipv6_enabled(void)
- {
- int fd = socket(AF_INET6, SOCK_DGRAM, 0);
- if (fd < 0)
- return false;
- close(fd);
- return true;
- }
- int main(int argc, char **argv)
- {
- openlog("odhcpd", LOG_PERROR | LOG_PID, LOG_DAEMON);
- int opt;
- while ((opt = getopt(argc, argv, "hl:")) != -1) {
- switch (opt) {
- case 'h':
- print_usage(argv[0]);
- return 0;
- case 'l':
- config.log_level = (atoi(optarg) & LOG_PRIMASK);
- fprintf(stderr, "Log level set to %d\n", config.log_level);
- break;
- }
- }
- setlogmask(LOG_UPTO(config.log_level));
- uloop_init();
- if (getuid() != 0) {
- syslog(LOG_ERR, "Must be run as root!");
- return 2;
- }
- ioctl_sock = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
- if (ioctl_sock < 0)
- return 4;
- if ((urandom_fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC)) < 0)
- return 4;
- signal(SIGUSR1, SIG_IGN);
- signal(SIGINT, sighandler);
- signal(SIGTERM, sighandler);
- if (netlink_init())
- return 4;
- if (ipv6_enabled()) {
- if (router_init())
- return 4;
- if (dhcpv6_init())
- return 4;
- if (ndp_init())
- return 4;
- }
- #ifndef DHCPV4_SUPPORT
- else
- return 4;
- #else
- if (dhcpv4_init())
- return 4;
- #endif
- odhcpd_run();
- return 0;
- }
- /* Read IPv6 MTU for interface */
- int odhcpd_get_interface_config(const char *ifname, const char *what)
- {
- char buf[64];
-
- snprintf(buf, sizeof(buf), "/proc/sys/net/ipv6/conf/%s/%s", ifname, what);
- int fd = open(buf, O_RDONLY);
- if (fd < 0)
- return -1;
- ssize_t len = read(fd, buf, sizeof(buf) - 1);
- close(fd);
- if (len < 0)
- return -1;
- buf[len] = 0;
- return atoi(buf);
- }
- /* Read IPv6 MAC for interface */
- int odhcpd_get_mac(const struct interface *iface, uint8_t mac[6])
- {
- struct ifreq ifr;
- memset(&ifr, 0, sizeof(ifr));
- strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name) - 1);
- if (ioctl(ioctl_sock, SIOCGIFHWADDR, &ifr) < 0)
- return -1;
- memcpy(mac, ifr.ifr_hwaddr.sa_data, 6);
- return 0;
- }
- int odhcpd_get_flags(const struct interface *iface)
- {
- struct ifreq ifr;
- memset(&ifr, 0, sizeof(ifr));
- strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name) - 1);
- if (ioctl(ioctl_sock, SIOCGIFFLAGS, &ifr) < 0)
- return -1;
- return ifr.ifr_flags;
- }
- /* Forwards a packet on a specific interface */
- ssize_t odhcpd_send(int socket, struct sockaddr_in6 *dest,
- struct iovec *iov, size_t iov_len,
- const struct interface *iface)
- {
- /* Construct headers */
- uint8_t cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))] = {0};
- struct msghdr msg = {
- .msg_name = (void *) dest,
- .msg_namelen = sizeof(*dest),
- .msg_iov = iov,
- .msg_iovlen = iov_len,
- .msg_control = cmsg_buf,
- .msg_controllen = sizeof(cmsg_buf),
- .msg_flags = 0
- };
- /* Set control data (define destination interface) */
- struct cmsghdr *chdr = CMSG_FIRSTHDR(&msg);
- chdr->cmsg_level = IPPROTO_IPV6;
- chdr->cmsg_type = IPV6_PKTINFO;
- chdr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
- struct in6_pktinfo *pktinfo = (struct in6_pktinfo*)CMSG_DATA(chdr);
- pktinfo->ipi6_ifindex = iface->ifindex;
- /* Also set scope ID if link-local */
- if (IN6_IS_ADDR_LINKLOCAL(&dest->sin6_addr)
- || IN6_IS_ADDR_MC_LINKLOCAL(&dest->sin6_addr))
- dest->sin6_scope_id = iface->ifindex;
- char ipbuf[INET6_ADDRSTRLEN];
- inet_ntop(AF_INET6, &dest->sin6_addr, ipbuf, sizeof(ipbuf));
- ssize_t sent = sendmsg(socket, &msg, MSG_DONTWAIT);
- if (sent < 0)
- syslog(LOG_ERR, "Failed to send to %s%%%s@%s (%m)",
- ipbuf, iface->name, iface->ifname);
- else
- syslog(LOG_DEBUG, "Sent %zd bytes to %s%%%s@%s",
- sent, ipbuf, iface->name, iface->ifname);
- return sent;
- }
- static int odhcpd_get_linklocal_interface_address(int ifindex, struct in6_addr *lladdr)
- {
- int ret = -1;
- struct sockaddr_in6 addr;
- socklen_t alen = sizeof(addr);
- int sock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
- if (sock < 0)
- return -1;
- memset(&addr, 0, sizeof(addr));
- addr.sin6_family = AF_INET6;
- inet_pton(AF_INET6, ALL_IPV6_ROUTERS, &addr.sin6_addr);
- addr.sin6_scope_id = ifindex;
- if (!connect(sock, (struct sockaddr*)&addr, sizeof(addr)) &&
- !getsockname(sock, (struct sockaddr*)&addr, &alen)) {
- *lladdr = addr.sin6_addr;
- ret = 0;
- }
- close(sock);
- return ret;
- }
- /*
- * DNS address selection criteria order :
- * - use IPv6 address with valid lifetime if none is yet selected
- * - use IPv6 address with a preferred lifetime if the already selected IPv6 address is deprecated
- * - use an IPv6 ULA address if the already selected IPv6 address is not an ULA address
- * - use the IPv6 address with the longest preferred lifetime
- */
- int odhcpd_get_interface_dns_addr(const struct interface *iface, struct in6_addr *addr)
- {
- time_t now = odhcpd_time();
- ssize_t m = -1;
- if (!iface->dns_service)
- return -1;
- for (size_t i = 0; i < iface->addr6_len; ++i) {
- if (iface->addr6[i].valid_lt <= (uint32_t)now)
- continue;
- if (m < 0) {
- m = i;
- continue;
- }
- if (iface->addr6[m].preferred_lt >= (uint32_t)now &&
- iface->addr6[i].preferred_lt < (uint32_t)now)
- continue;
- if (IN6_IS_ADDR_ULA(&iface->addr6[i].addr.in6)) {
- if (!IN6_IS_ADDR_ULA(&iface->addr6[m].addr.in6)) {
- m = i;
- continue;
- }
- } else if (IN6_IS_ADDR_ULA(&iface->addr6[m].addr.in6))
- continue;
- if (iface->addr6[i].preferred_lt > iface->addr6[m].preferred_lt)
- m = i;
- }
- if (m >= 0) {
- *addr = iface->addr6[m].addr.in6;
- return 0;
- }
- return odhcpd_get_linklocal_interface_address(iface->ifindex, addr);
- }
- struct interface* odhcpd_get_interface_by_index(int ifindex)
- {
- struct interface *iface;
- avl_for_each_element(&interfaces, iface, avl) {
- if (iface->ifindex == ifindex)
- return iface;
- }
- return NULL;
- }
- /* Convenience function to receive and do basic validation of packets */
- static void odhcpd_receive_packets(struct uloop_fd *u, _unused unsigned int events)
- {
- struct odhcpd_event *e = container_of(u, struct odhcpd_event, uloop);
- uint8_t data_buf[8192], cmsg_buf[128];
- union {
- struct sockaddr_in6 in6;
- struct sockaddr_in in;
- struct sockaddr_ll ll;
- struct sockaddr_nl nl;
- } addr;
- if (u->error) {
- int ret = -1;
- socklen_t ret_len = sizeof(ret);
- u->error = false;
- if (e->handle_error && getsockopt(u->fd, SOL_SOCKET, SO_ERROR, &ret, &ret_len) == 0)
- e->handle_error(e, ret);
- }
- if (e->recv_msgs) {
- e->recv_msgs(e);
- return;
- }
- while (true) {
- struct iovec iov = {data_buf, sizeof(data_buf)};
- struct msghdr msg = {
- .msg_name = (void *) &addr,
- .msg_namelen = sizeof(addr),
- .msg_iov = &iov,
- .msg_iovlen = 1,
- .msg_control = cmsg_buf,
- .msg_controllen = sizeof(cmsg_buf),
- .msg_flags = 0
- };
- ssize_t len = recvmsg(u->fd, &msg, MSG_DONTWAIT);
- if (len < 0) {
- if (errno == EAGAIN)
- break;
- else
- continue;
- }
- /* Extract destination interface */
- int destiface = 0;
- int *hlim = NULL;
- void *dest = NULL;
- struct in6_pktinfo *pktinfo;
- struct in_pktinfo *pkt4info;
- for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL; ch = CMSG_NXTHDR(&msg, ch)) {
- if (ch->cmsg_level == IPPROTO_IPV6 &&
- ch->cmsg_type == IPV6_PKTINFO) {
- pktinfo = (struct in6_pktinfo*)CMSG_DATA(ch);
- destiface = pktinfo->ipi6_ifindex;
- dest = &pktinfo->ipi6_addr;
- } else if (ch->cmsg_level == IPPROTO_IP &&
- ch->cmsg_type == IP_PKTINFO) {
- pkt4info = (struct in_pktinfo*)CMSG_DATA(ch);
- destiface = pkt4info->ipi_ifindex;
- dest = &pkt4info->ipi_addr;
- } else if (ch->cmsg_level == IPPROTO_IPV6 &&
- ch->cmsg_type == IPV6_HOPLIMIT) {
- hlim = (int*)CMSG_DATA(ch);
- }
- }
- /* Check hoplimit if received */
- if (hlim && *hlim != 255)
- continue;
- /* Detect interface for packet sockets */
- if (addr.ll.sll_family == AF_PACKET)
- destiface = addr.ll.sll_ifindex;
- char ipbuf[INET6_ADDRSTRLEN] = "kernel";
- if (addr.ll.sll_family == AF_PACKET &&
- len >= (ssize_t)sizeof(struct ip6_hdr))
- inet_ntop(AF_INET6, &data_buf[8], ipbuf, sizeof(ipbuf));
- else if (addr.in6.sin6_family == AF_INET6)
- inet_ntop(AF_INET6, &addr.in6.sin6_addr, ipbuf, sizeof(ipbuf));
- else if (addr.in.sin_family == AF_INET)
- inet_ntop(AF_INET, &addr.in.sin_addr, ipbuf, sizeof(ipbuf));
- /* From netlink */
- if (addr.nl.nl_family == AF_NETLINK) {
- syslog(LOG_DEBUG, "Received %zd Bytes from %s%%netlink", len,
- ipbuf);
- e->handle_dgram(&addr, data_buf, len, NULL, dest);
- return;
- } else if (destiface != 0) {
- struct interface *iface;
- avl_for_each_element(&interfaces, iface, avl) {
- if (iface->ifindex != destiface)
- continue;
- syslog(LOG_DEBUG, "Received %zd Bytes from %s%%%s@%s", len,
- ipbuf, iface->name, iface->ifname);
- e->handle_dgram(&addr, data_buf, len, iface, dest);
- }
- }
- }
- }
- /* Register events for the multiplexer */
- int odhcpd_register(struct odhcpd_event *event)
- {
- event->uloop.cb = odhcpd_receive_packets;
- return uloop_fd_add(&event->uloop, ULOOP_READ |
- ((event->handle_error) ? ULOOP_ERROR_CB : 0));
- }
- int odhcpd_deregister(struct odhcpd_event *event)
- {
- event->uloop.cb = NULL;
- return uloop_fd_delete(&event->uloop);
- }
- void odhcpd_process(struct odhcpd_event *event)
- {
- odhcpd_receive_packets(&event->uloop, 0);
- }
- int odhcpd_urandom(void *data, size_t len)
- {
- return read(urandom_fd, data, len);
- }
- time_t odhcpd_time(void)
- {
- struct timespec ts;
- clock_gettime(CLOCK_MONOTONIC, &ts);
- return ts.tv_sec;
- }
- static const char hexdigits[] = "0123456789abcdef";
- static const int8_t hexvals[] = {
- -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
- -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
- -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
- 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
- -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
- -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
- -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
- -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
- };
- ssize_t odhcpd_unhexlify(uint8_t *dst, size_t len, const char *src)
- {
- size_t c;
- for (c = 0; c < len && src[0] && src[1]; ++c) {
- int8_t x = (int8_t)*src++;
- int8_t y = (int8_t)*src++;
- if (x < 0 || (x = hexvals[x]) < 0
- || y < 0 || (y = hexvals[y]) < 0)
- return -1;
- dst[c] = x << 4 | y;
- while (((int8_t)*src) < 0 ||
- (*src && hexvals[(uint8_t)*src] < 0))
- src++;
- }
- return c;
- }
- void odhcpd_hexlify(char *dst, const uint8_t *src, size_t len)
- {
- for (size_t i = 0; i < len; ++i) {
- *dst++ = hexdigits[src[i] >> 4];
- *dst++ = hexdigits[src[i] & 0x0f];
- }
- *dst = 0;
- }
- const char *odhcpd_print_mac(const uint8_t *mac, const size_t len)
- {
- static char buf[32];
- snprintf(buf, sizeof(buf), "%02x", mac[0]);
- for (size_t i = 1, j = 2; i < len && j < sizeof(buf); i++, j += 3)
- snprintf(buf + j, sizeof(buf) - j, ":%02x", mac[i]);
- return buf;
- }
- int odhcpd_bmemcmp(const void *av, const void *bv, size_t bits)
- {
- const uint8_t *a = av, *b = bv;
- size_t bytes = bits / 8;
- bits %= 8;
- int res = memcmp(a, b, bytes);
- if (res == 0 && bits > 0)
- res = (a[bytes] >> (8 - bits)) - (b[bytes] >> (8 - bits));
- return res;
- }
- void odhcpd_bmemcpy(void *av, const void *bv, size_t bits)
- {
- uint8_t *a = av;
- const uint8_t *b = bv;
- size_t bytes = bits / 8;
- bits %= 8;
- memcpy(a, b, bytes);
- if (bits > 0) {
- uint8_t mask = (1 << (8 - bits)) - 1;
- a[bytes] = (a[bytes] & mask) | ((~mask) & b[bytes]);
- }
- }
- int odhcpd_netmask2bitlen(bool inet6, void *mask)
- {
- int bits;
- struct in_addr *v4;
- struct in6_addr *v6;
- if (inet6)
- for (bits = 0, v6 = mask;
- bits < 128 && (v6->s6_addr[bits / 8] << (bits % 8)) & 128;
- bits++);
- else
- for (bits = 0, v4 = mask;
- bits < 32 && (ntohl(v4->s_addr) << bits) & 0x80000000;
- bits++);
- return bits;
- }
- bool odhcpd_bitlen2netmask(bool inet6, unsigned int bits, void *mask)
- {
- uint8_t b;
- struct in_addr *v4;
- struct in6_addr *v6;
- if (inet6)
- {
- if (bits > 128)
- return false;
- v6 = mask;
- for (unsigned int i = 0; i < sizeof(v6->s6_addr); i++)
- {
- b = (bits > 8) ? 8 : bits;
- v6->s6_addr[i] = (uint8_t)(0xFF << (8 - b));
- bits -= b;
- }
- }
- else
- {
- if (bits > 32)
- return false;
- v4 = mask;
- v4->s_addr = bits ? htonl(~((1 << (32 - bits)) - 1)) : 0;
- }
- return true;
- }
- bool odhcpd_valid_hostname(const char *name)
- {
- #define MAX_LABEL 63
- const char *c, *label, *label_end;
- int label_sz = 0;
- for (c = name, label_sz = 0, label = name, label_end = name + strcspn(name, ".") - 1;
- *c && label_sz <= MAX_LABEL; c++) {
- if ((*c >= '0' && *c <= '9') ||
- (*c >= 'A' && *c <= 'Z') ||
- (*c >= 'a' && *c <= 'z')) {
- label_sz++;
- continue;
- }
- if ((*c == '_' || *c == '-') && c != label && c != label_end) {
- label_sz++;
- continue;
- }
- if (*c == '.') {
- if (*(c + 1)) {
- label = c + 1;
- label_end = label + strcspn(label, ".") - 1;
- label_sz = 0;
- }
- continue;
- }
- return false;
- }
- return (label_sz && label_sz <= MAX_LABEL ? true : false);
- }
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