diff options
Diffstat (limited to 'networking/udhcp/dhcpd.c')
| -rw-r--r-- | networking/udhcp/dhcpd.c | 272 |
1 files changed, 272 insertions, 0 deletions
diff --git a/networking/udhcp/dhcpd.c b/networking/udhcp/dhcpd.c new file mode 100644 index 0000000..b512c45 --- /dev/null +++ b/networking/udhcp/dhcpd.c @@ -0,0 +1,272 @@ +/* vi: set sw=4 ts=4: */ +/* dhcpd.c + * + * udhcp Server + * Copyright (C) 1999 Matthew Ramsay <matthewr@moreton.com.au> + * Chris Trew <ctrew@moreton.com.au> + * + * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001 + * + * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. + */ + +#include <syslog.h> +#include "common.h" +#include "dhcpc.h" +#include "dhcpd.h" +#include "options.h" + + +/* globals */ +struct dhcpOfferedAddr *leases; +/* struct server_config_t server_config is in bb_common_bufsiz1 */ + + +int udhcpd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; +int udhcpd_main(int argc UNUSED_PARAM, char **argv) +{ + fd_set rfds; + struct timeval tv; + int server_socket = -1, bytes, retval, max_sock; + struct dhcpMessage packet; + uint8_t *state, *server_id, *requested; + uint32_t server_id_align, requested_align, static_lease_ip; + unsigned timeout_end; + unsigned num_ips; + unsigned opt; + struct option_set *option; + struct dhcpOfferedAddr *lease, static_lease; + USE_FEATURE_UDHCP_PORT(char *str_P;) + +#if ENABLE_FEATURE_UDHCP_PORT + SERVER_PORT = 67; + CLIENT_PORT = 68; +#endif + + opt = getopt32(argv, "fS" USE_FEATURE_UDHCP_PORT("P:", &str_P)); + argv += optind; + + if (!(opt & 1)) { /* no -f */ + bb_daemonize_or_rexec(0, argv); + logmode &= ~LOGMODE_STDIO; + } + + if (opt & 2) { /* -S */ + openlog(applet_name, LOG_PID, LOG_LOCAL0); + logmode |= LOGMODE_SYSLOG; + } +#if ENABLE_FEATURE_UDHCP_PORT + if (opt & 4) { /* -P */ + SERVER_PORT = xatou16(str_P); + CLIENT_PORT = SERVER_PORT + 1; + } +#endif + /* Would rather not do read_config before daemonization - + * otherwise NOMMU machines will parse config twice */ + read_config(argv[0] ? argv[0] : DHCPD_CONF_FILE); + + /* Make sure fd 0,1,2 are open */ + bb_sanitize_stdio(); + /* Equivalent of doing a fflush after every \n */ + setlinebuf(stdout); + + /* Create pidfile */ + write_pidfile(server_config.pidfile); + /* if (!..) bb_perror_msg("cannot create pidfile %s", pidfile); */ + + bb_info_msg("%s (v"BB_VER") started", applet_name); + + option = find_option(server_config.options, DHCP_LEASE_TIME); + server_config.lease = LEASE_TIME; + if (option) { + memcpy(&server_config.lease, option->data + 2, 4); + server_config.lease = ntohl(server_config.lease); + } + + /* Sanity check */ + num_ips = server_config.end_ip - server_config.start_ip + 1; + if (server_config.max_leases > num_ips) { + bb_error_msg("max_leases=%u is too big, setting to %u", + (unsigned)server_config.max_leases, num_ips); + server_config.max_leases = num_ips; + } + + leases = xzalloc(server_config.max_leases * sizeof(*leases)); + read_leases(server_config.lease_file); + + if (udhcp_read_interface(server_config.interface, &server_config.ifindex, + &server_config.server, server_config.arp)) { + retval = 1; + goto ret; + } + + /* Setup the signal pipe */ + udhcp_sp_setup(); + + timeout_end = monotonic_sec() + server_config.auto_time; + while (1) { /* loop until universe collapses */ + + if (server_socket < 0) { + server_socket = udhcp_listen_socket(/*INADDR_ANY,*/ SERVER_PORT, + server_config.interface); + } + + max_sock = udhcp_sp_fd_set(&rfds, server_socket); + if (server_config.auto_time) { + tv.tv_sec = timeout_end - monotonic_sec(); + tv.tv_usec = 0; + } + retval = 0; + if (!server_config.auto_time || tv.tv_sec > 0) { + retval = select(max_sock + 1, &rfds, NULL, NULL, + server_config.auto_time ? &tv : NULL); + } + if (retval == 0) { + write_leases(); + timeout_end = monotonic_sec() + server_config.auto_time; + continue; + } + if (retval < 0 && errno != EINTR) { + DEBUG("error on select"); + continue; + } + + switch (udhcp_sp_read(&rfds)) { + case SIGUSR1: + bb_info_msg("Received a SIGUSR1"); + write_leases(); + /* why not just reset the timeout, eh */ + timeout_end = monotonic_sec() + server_config.auto_time; + continue; + case SIGTERM: + bb_info_msg("Received a SIGTERM"); + goto ret0; + case 0: break; /* no signal */ + default: continue; /* signal or error (probably EINTR) */ + } + + bytes = udhcp_recv_kernel_packet(&packet, server_socket); /* this waits for a packet - idle */ + if (bytes < 0) { + if (bytes == -1 && errno != EINTR) { + DEBUG("error on read, %s, reopening socket", strerror(errno)); + close(server_socket); + server_socket = -1; + } + continue; + } + + state = get_option(&packet, DHCP_MESSAGE_TYPE); + if (state == NULL) { + bb_error_msg("cannot get option from packet, ignoring"); + continue; + } + + /* Look for a static lease */ + static_lease_ip = getIpByMac(server_config.static_leases, &packet.chaddr); + + if (static_lease_ip) { + bb_info_msg("Found static lease: %x", static_lease_ip); + + memcpy(&static_lease.chaddr, &packet.chaddr, 16); + static_lease.yiaddr = static_lease_ip; + static_lease.expires = 0; + + lease = &static_lease; + } else { + lease = find_lease_by_chaddr(packet.chaddr); + } + + switch (state[0]) { + case DHCPDISCOVER: + DEBUG("Received DISCOVER"); + + if (send_offer(&packet) < 0) { + bb_error_msg("send OFFER failed"); + } + break; + case DHCPREQUEST: + DEBUG("received REQUEST"); + + requested = get_option(&packet, DHCP_REQUESTED_IP); + server_id = get_option(&packet, DHCP_SERVER_ID); + + if (requested) memcpy(&requested_align, requested, 4); + if (server_id) memcpy(&server_id_align, server_id, 4); + + if (lease) { + if (server_id) { + /* SELECTING State */ + DEBUG("server_id = %08x", ntohl(server_id_align)); + if (server_id_align == server_config.server && requested + && requested_align == lease->yiaddr + ) { + send_ACK(&packet, lease->yiaddr); + } + } else if (requested) { + /* INIT-REBOOT State */ + if (lease->yiaddr == requested_align) + send_ACK(&packet, lease->yiaddr); + else + send_NAK(&packet); + } else if (lease->yiaddr == packet.ciaddr) { + /* RENEWING or REBINDING State */ + send_ACK(&packet, lease->yiaddr); + } else { /* don't know what to do!!!! */ + send_NAK(&packet); + } + + /* what to do if we have no record of the client */ + } else if (server_id) { + /* SELECTING State */ + + } else if (requested) { + /* INIT-REBOOT State */ + lease = find_lease_by_yiaddr(requested_align); + if (lease) { + if (lease_expired(lease)) { + /* probably best if we drop this lease */ + memset(lease->chaddr, 0, 16); + /* make some contention for this address */ + } else + send_NAK(&packet); + } else { + uint32_t r = ntohl(requested_align); + if (r < server_config.start_ip + || r > server_config.end_ip + ) { + send_NAK(&packet); + } + /* else remain silent */ + } + + } else { + /* RENEWING or REBINDING State */ + } + break; + case DHCPDECLINE: + DEBUG("Received DECLINE"); + if (lease) { + memset(lease->chaddr, 0, 16); + lease->expires = time(0) + server_config.decline_time; + } + break; + case DHCPRELEASE: + DEBUG("Received RELEASE"); + if (lease) + lease->expires = time(0); + break; + case DHCPINFORM: + DEBUG("Received INFORM"); + send_inform(&packet); + break; + default: + bb_info_msg("Unsupported DHCP message (%02x) - ignoring", state[0]); + } + } + ret0: + retval = 0; + ret: + /*if (server_config.pidfile) - server_config.pidfile is never NULL */ + remove_pidfile(server_config.pidfile); + return retval; +} |