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-rw-r--r--src/odhcpd.c423
1 files changed, 423 insertions, 0 deletions
diff --git a/src/odhcpd.c b/src/odhcpd.c
new file mode 100644
index 0000000..6070bfb
--- /dev/null
+++ b/src/odhcpd.c
@@ -0,0 +1,423 @@
+/**
+ * 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 <arpa/inet.h>
+#include <net/if.h>
+#include <netinet/ip6.h>
+#include <netpacket/packet.h>
+#include <linux/rtnetlink.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;
+static int rtnl_socket = -1;
+static int rtnl_seq = 0;
+static int urandom_fd = -1;
+
+
+int main()
+{
+ openlog("odhcpd", LOG_PERROR | LOG_PID, LOG_DAEMON);
+ 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 ((rtnl_socket = odhcpd_open_rtnl()) < 0) {
+ syslog(LOG_ERR, "Unable to open socket: %s", strerror(errno));
+ return 2;
+ }
+
+ if ((urandom_fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC)) < 0)
+ return 4;
+
+ signal(SIGUSR1, SIG_IGN);
+
+ if (init_router())
+ return 4;
+
+ if (init_dhcpv6())
+ return 4;
+
+ if (init_ndp())
+ return 4;
+
+ if (init_dhcpv4())
+ return 4;
+
+ if (init_ubus())
+ return 4;
+
+ odhcpd_run();
+ return 0;
+}
+
+int odhcpd_open_rtnl(void)
+{
+ int sock = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, NETLINK_ROUTE);
+
+ // Connect to the kernel netlink interface
+ struct sockaddr_nl nl = {.nl_family = AF_NETLINK};
+ if (connect(sock, (struct sockaddr*)&nl, sizeof(nl))) {
+ syslog(LOG_ERR, "Failed to connect to kernel rtnetlink: %s",
+ strerror(errno));
+ return -1;
+ }
+
+ return sock;
+}
+
+
+// Read IPv6 MTU for interface
+int odhcpd_get_interface_mtu(const char *ifname)
+{
+ char buf[64];
+ const char *sysctl_pattern = "/proc/sys/net/ipv6/conf/%s/mtu";
+ snprintf(buf, sizeof(buf), sysctl_pattern, ifname);
+
+ int fd = open(buf, O_RDONLY);
+ 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;
+ strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name));
+ if (ioctl(ioctl_sock, SIOCGIFHWADDR, &ifr) < 0)
+ return -1;
+ memcpy(mac, ifr.ifr_hwaddr.sa_data, 6);
+ return 0;
+}
+
+
+// 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 = {(void*)dest, sizeof(*dest), iov, iov_len,
+ cmsg_buf, sizeof(cmsg_buf), 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;
+
+ // IPV6_PKTINFO doesn't really work for IPv6-raw sockets (bug?)
+ if (dest->sin6_port == 0) {
+ msg.msg_control = NULL;
+ msg.msg_controllen = 0;
+ }
+
+ 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_WARNING, "Failed to send to %s%%%s (%s)",
+ ipbuf, iface->ifname, strerror(errno));
+ else
+ syslog(LOG_NOTICE, "Sent %li bytes to %s%%%s",
+ (long)sent, ipbuf, iface->ifname);
+ return sent;
+}
+
+
+// Detect an IPV6-address currently assigned to the given interface
+ssize_t odhcpd_get_interface_addresses(int ifindex,
+ struct odhcpd_ipaddr *addrs, size_t cnt)
+{
+ struct {
+ struct nlmsghdr nhm;
+ struct ifaddrmsg ifa;
+ } req = {{sizeof(req), RTM_GETADDR, NLM_F_REQUEST | NLM_F_DUMP,
+ ++rtnl_seq, 0}, {AF_INET6, 0, 0, 0, ifindex}};
+ if (send(rtnl_socket, &req, sizeof(req), 0) < (ssize_t)sizeof(req))
+ return 0;
+
+ uint8_t buf[8192];
+ ssize_t len = 0, ret = 0;
+
+ for (struct nlmsghdr *nhm = NULL; ; nhm = NLMSG_NEXT(nhm, len)) {
+ while (len < 0 || !NLMSG_OK(nhm, (size_t)len)) {
+ len = recv(rtnl_socket, buf, sizeof(buf), 0);
+ nhm = (struct nlmsghdr*)buf;
+ if (len < 0 || !NLMSG_OK(nhm, (size_t)len)) {
+ if (errno == EINTR)
+ continue;
+ else
+ return ret;
+ }
+ }
+
+ if (nhm->nlmsg_type != RTM_NEWADDR)
+ break;
+
+ // Skip address but keep clearing socket buffer
+ if (ret >= (ssize_t)cnt)
+ continue;
+
+ struct ifaddrmsg *ifa = NLMSG_DATA(nhm);
+ if (ifa->ifa_scope != RT_SCOPE_UNIVERSE ||
+ ifa->ifa_index != (unsigned)ifindex)
+ continue;
+
+ struct rtattr *rta = (struct rtattr*)&ifa[1];
+ size_t alen = NLMSG_PAYLOAD(nhm, sizeof(*ifa));
+ memset(&addrs[ret], 0, sizeof(addrs[ret]));
+ addrs[ret].prefix = ifa->ifa_prefixlen;
+
+ while (RTA_OK(rta, alen)) {
+ if (rta->rta_type == IFA_ADDRESS) {
+ memcpy(&addrs[ret].addr, RTA_DATA(rta),
+ sizeof(struct in6_addr));
+ } else if (rta->rta_type == IFA_CACHEINFO) {
+ struct ifa_cacheinfo *ifc = RTA_DATA(rta);
+ addrs[ret].preferred = ifc->ifa_prefered;
+ addrs[ret].valid = ifc->ifa_valid;
+ }
+
+ rta = RTA_NEXT(rta, alen);
+ }
+
+ if (ifa->ifa_flags & IFA_F_DEPRECATED)
+ addrs[ret].preferred = 0;
+
+ ++ret;
+ }
+
+ return ret;
+}
+
+
+struct interface* odhcpd_get_interface_by_index(int ifindex)
+{
+ struct interface *iface;
+ list_for_each_entry(iface, &interfaces, head)
+ if (iface->ifindex == ifindex)
+ return iface;
+
+ return NULL;
+}
+
+
+struct interface* odhcpd_get_interface_by_name(const char *name)
+{
+ struct interface *iface;
+ list_for_each_entry(iface, &interfaces, head)
+ if (!strcmp(iface->ifname, name))
+ return iface;
+
+ return NULL;
+}
+
+
+struct interface* odhcpd_get_master_interface(void)
+{
+ struct interface *iface;
+ list_for_each_entry(iface, &interfaces, head)
+ if (iface->master)
+ 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[RELAYD_BUFFER_SIZE], cmsg_buf[128];
+ union {
+ struct sockaddr_in6 in6;
+ struct sockaddr_in in;
+ struct sockaddr_ll ll;
+ struct sockaddr_nl nl;
+ } addr;
+
+ while (true) {
+ struct iovec iov = {data_buf, sizeof(data_buf)};
+ struct msghdr msg = {&addr, sizeof(addr), &iov, 1,
+ cmsg_buf, sizeof(cmsg_buf), 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;
+ struct in6_pktinfo *pktinfo;
+ struct in_pktinfo *pkt4info;
+ for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL &&
+ destiface == 0; 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;
+ } else if (ch->cmsg_level == IPPROTO_IP &&
+ ch->cmsg_type == IP_PKTINFO) {
+ pkt4info = (struct in_pktinfo*)CMSG_DATA(ch);
+ destiface = pkt4info->ipi_ifindex;
+ } 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;
+
+ struct interface *iface =
+ odhcpd_get_interface_by_index(destiface);
+
+ if (!iface && addr.nl.nl_family != AF_NETLINK)
+ continue;
+
+ 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));
+
+ syslog(LOG_NOTICE, "--");
+ syslog(LOG_NOTICE, "Received %li Bytes from %s%%%s", (long)len,
+ ipbuf, (iface) ? iface->ifname : "netlink");
+
+ e->handle_dgram(&addr, data_buf, len, iface);
+ }
+}
+
+// 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);
+}
+
+void odhcpd_urandom(void *data, size_t len)
+{
+ read(urandom_fd, data, len);
+}
+
+
+time_t odhcpd_time(void)
+{
+ struct timespec ts;
+ syscall(SYS_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;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 23:26:55 +0000