Split state machine apart into functions.
This commit is contained in:
Nicholas J. Kain
parent
6772ddac1b
commit
406e316274
416
ndhc/ndhc.c
416
ndhc/ndhc.c
@ -321,100 +321,241 @@ static void arp_success(void)
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background();
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}
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/* Handle select timeout dropping to zero */
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static void init_selecting_timeout()
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{
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if (packet_num < NUMPACKETS) {
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if (packet_num == 0)
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xid = random_xid();
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/* broadcast */
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send_discover(xid, requested_ip);
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timeout = ((packet_num == NUMPACKETS - 1) ? 4 : 2) * 1000;
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packet_num++;
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} else {
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if (client_config.background_if_no_lease) {
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log_line("No lease, going to background.");
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background();
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} else if (client_config.abort_if_no_lease) {
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log_line("No lease, failing.");
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exit(EXIT_FAILURE);
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}
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/* wait to try again */
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packet_num = 0;
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timeout = RETRY_DELAY * 1000;
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}
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}
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static void renew_requested_timeout()
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{
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if (packet_num < NUMPACKETS) {
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/* send unicast request packet */
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send_renew(xid, server_addr, requested_ip);
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timeout = ((packet_num == NUMPACKETS - 1) ? 10 : 2) * 1000;
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packet_num++;
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} else {
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/* timed out, go back to init state */
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run_script(NULL, SCRIPT_DECONFIG);
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dhcp_state = INIT_SELECTING;
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timeout = 0;
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packet_num = 0;
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change_listen_mode(LISTEN_RAW);
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}
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}
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static void requesting_timeout()
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{
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if (packet_num < NUMPACKETS) {
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/* send broadcast request packet */
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send_selecting(xid, server_addr, requested_ip);
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timeout = ((packet_num == NUMPACKETS - 1) ? 10 : 2) * 1000;
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packet_num++;
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} else {
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/* timed out, go back to init state */
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dhcp_state = INIT_SELECTING;
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timeout = 0;
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packet_num = 0;
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change_listen_mode(LISTEN_RAW);
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}
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}
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static void renewing_timeout()
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{
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/* Either set a new T1, or enter REBINDING state */
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if ((t2 - t1) <= (lease / 14400 + 1)) {
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/* timed out, enter rebinding state */
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dhcp_state = REBINDING;
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timeout = (t2 - t1) * 1000;
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log_line("Entering rebinding state.");
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} else {
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/* send a request packet */
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send_renew(xid, server_addr, requested_ip); /* unicast */
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t1 = ((t2 - t1) >> 1) + t1;
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timeout = (t1 * 1000) - (curms() - start);
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}
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}
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static void bound_timeout()
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{
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/* Lease is starting to run out, time to enter renewing state */
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dhcp_state = RENEWING;
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change_listen_mode(LISTEN_KERNEL);
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log_line("Entering renew state.");
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renewing_timeout();
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}
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static void rebinding_timeout()
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{
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/* Either set a new T2, or enter INIT state */
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if ((lease - t2) <= (lease / 14400 + 1)) {
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/* timed out, enter init state */
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dhcp_state = INIT_SELECTING;
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log_line("Lease lost, entering init state.");
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run_script(NULL, SCRIPT_DECONFIG);
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timeout = 0;
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packet_num = 0;
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change_listen_mode(LISTEN_RAW);
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} else {
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/* send a request packet */
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send_renew(xid, 0, requested_ip); /* broadcast */
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t2 = ((lease - t2) >> 1) + t2;
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timeout = (t2 * 1000) - (curms() - start);
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}
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}
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/* Handle epoll timeout expiring */
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static void handle_timeout(void)
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{
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switch (dhcp_state) {
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case INIT_SELECTING:
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if (packet_num < NUMPACKETS) {
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if (packet_num == 0)
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xid = random_xid();
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/* broadcast */
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send_discover(xid, requested_ip);
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case INIT_SELECTING: init_selecting_timeout(); break;
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case RENEW_REQUESTED: renew_requested_timeout(); break;
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case REQUESTING: requesting_timeout(); break;
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case RENEWING: renewing_timeout(); break;
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case BOUND: bound_timeout(); break;
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case REBINDING: rebinding_timeout(); break;
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case RELEASED: timeout = -1; break;
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case ARP_CHECK: arp_success(); break;
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default: break;
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}
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}
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timeout = ((packet_num == NUMPACKETS - 1) ? 4 : 2) * 1000;
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packet_num++;
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} else {
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if (client_config.background_if_no_lease) {
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log_line("No lease, going to background.");
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background();
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} else if (client_config.abort_if_no_lease) {
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log_line("No lease, failing.");
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exit(EXIT_FAILURE);
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}
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/* wait to try again */
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packet_num = 0;
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timeout = RETRY_DELAY * 1000;
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}
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static void init_selecting_packet(struct dhcpMessage *packet,
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unsigned char *message)
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{
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unsigned char *temp = NULL;
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/* Must be a DHCPOFFER to one of our xid's */
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if (*message == DHCPOFFER) {
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if ((temp = get_option(packet, DHCP_SERVER_ID))) {
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/* Memcpy to a temp buffer to force alignment */
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memcpy(&server_addr, temp, 4);
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xid = packet->xid;
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requested_ip = packet->yiaddr;
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/* enter requesting state */
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dhcp_state = REQUESTING;
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timeout = 0;
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packet_num = 0;
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} else {
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log_line("No server ID in message");
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}
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}
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}
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static void dhcp_ack_or_nak_packet(struct dhcpMessage *packet,
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unsigned char *message)
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{
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unsigned char *temp = NULL;
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if (*message == DHCPACK) {
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if (!(temp = get_option(packet, DHCP_LEASE_TIME))) {
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log_line("No lease time received, assuming 1h.");
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lease = 60 * 60;
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} else {
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/* Memcpy to a temp buffer to force alignment */
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memcpy(&lease, temp, 4);
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lease = ntohl(lease);
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/* Enforce upper and lower bounds on lease. */
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lease &= 0x0fffffff;
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if (lease < RETRY_DELAY)
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lease = RETRY_DELAY;
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}
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arp_prev_dhcp_state = dhcp_state;
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dhcp_state = ARP_CHECK;
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memcpy(&arp_dhcp_packet, packet, sizeof (struct dhcpMessage));
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arpFd = arpping(arp_dhcp_packet.yiaddr, NULL, 0,
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client_config.arp, client_config.interface);
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epoll_add(arpFd);
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timeout = 2000;
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memset(&arpreply, 0, sizeof arpreply);
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arpreply_offset = 0;
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// Can transition to BOUND or INIT_SELECTING.
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} else if (*message == DHCPNAK) {
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/* return to init state */
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log_line("Received DHCP NAK.");
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run_script(packet, SCRIPT_NAK);
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if (dhcp_state != REQUESTING)
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run_script(NULL, SCRIPT_DECONFIG);
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dhcp_state = INIT_SELECTING;
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timeout = 0;
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requested_ip = 0;
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packet_num = 0;
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change_listen_mode(LISTEN_RAW);
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// XXX: this isn't rfc compliant: should be exp backoff
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sleep(3); /* avoid excessive network traffic */
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}
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}
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static void handle_packet(void)
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{
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unsigned char *message = NULL;
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int len;
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struct dhcpMessage packet;
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if (listen_mode == LISTEN_KERNEL)
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len = get_packet(&packet, listenFd);
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else if (listen_mode == LISTEN_RAW)
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len = get_raw_packet(&packet, listenFd);
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else /* LISTEN_NONE */
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return;
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if (len == -1 && errno != EINTR) {
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log_error("reopening socket.");
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change_listen_mode(listen_mode); /* just close and reopen */
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}
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if (len < 0)
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return;
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if (packet.xid != xid) {
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log_line("Ignoring XID %lx (our xid is %lx).",
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(uint32_t) packet.xid, xid);
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return;
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}
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if ((message = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
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log_line("couldnt get option from packet -- ignoring");
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return;
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}
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switch (dhcp_state) {
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case INIT_SELECTING:
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init_selecting_packet(&packet, message);
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break;
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case ARP_CHECK:
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/* We ignore dhcp packets for now. This state will
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* be changed by the callback for arp ping.
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*/
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break;
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case RENEW_REQUESTED:
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case REQUESTING:
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if (packet_num < NUMPACKETS) {
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/* send request packet */
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if (dhcp_state == RENEW_REQUESTED)
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/* unicast */
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send_renew(xid, server_addr, requested_ip);
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else
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/* broadcast */
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send_selecting(xid, server_addr, requested_ip);
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timeout = ((packet_num == NUMPACKETS - 1) ? 10 : 2) * 1000;
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packet_num++;
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} else {
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/* timed out, go back to init state */
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if (dhcp_state == RENEW_REQUESTED)
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run_script(NULL, SCRIPT_DECONFIG);
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dhcp_state = INIT_SELECTING;
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timeout = 0;
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packet_num = 0;
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change_listen_mode(LISTEN_RAW);
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}
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case RENEWING:
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case REBINDING:
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dhcp_ack_or_nak_packet(&packet, message);
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break;
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case BOUND:
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/* Lease is starting to run out, time to enter renewing state */
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dhcp_state = RENEWING;
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change_listen_mode(LISTEN_KERNEL);
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log_line("Entering renew state.");
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/* fall right through */
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case RENEWING:
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/* Either set a new T1, or enter REBINDING state */
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if ((t2 - t1) <= (lease / 14400 + 1)) {
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/* timed out, enter rebinding state */
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dhcp_state = REBINDING;
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timeout = (t2 - t1) * 1000;
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log_line("Entering rebinding state.");
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} else {
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/* send a request packet */
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send_renew(xid, server_addr, requested_ip); /* unicast */
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t1 = ((t2 - t1) >> 1) + t1;
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timeout = (t1 * 1000) - (curms() - start);
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}
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break;
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case REBINDING:
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/* Either set a new T2, or enter INIT state */
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if ((lease - t2) <= (lease / 14400 + 1)) {
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/* timed out, enter init state */
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dhcp_state = INIT_SELECTING;
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log_line("Lease lost, entering init state.");
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run_script(NULL, SCRIPT_DECONFIG);
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timeout = 0;
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packet_num = 0;
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change_listen_mode(LISTEN_RAW);
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} else {
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/* send a request packet */
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send_renew(xid, 0, requested_ip); /* broadcast */
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t2 = ((lease - t2) >> 1) + t2;
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timeout = (t2 * 1000) - (curms() - start);
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}
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break;
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case RELEASED:
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/* yah, I know, *you* say it would never happen */
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timeout = -1;
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break;
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case ARP_CHECK:
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/* No response to ARP obviously means that the address is free. */
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arp_success();
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default:
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break;
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}
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@ -457,113 +598,6 @@ static void handle_arp_response(void)
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}
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}
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static void handle_packet(void)
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{
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unsigned char *temp = NULL, *message = NULL;
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int len;
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struct dhcpMessage packet;
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if (listen_mode == LISTEN_KERNEL)
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len = get_packet(&packet, listenFd);
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else if (listen_mode == LISTEN_RAW)
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len = get_raw_packet(&packet, listenFd);
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else /* LISTEN_NONE */
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return;
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if (len == -1 && errno != EINTR) {
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log_error("reopening socket.");
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change_listen_mode(listen_mode); /* just close and reopen */
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}
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if (len < 0)
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return;
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if (packet.xid != xid) {
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log_line("Ignoring XID %lx (our xid is %lx).",
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(uint32_t) packet.xid, xid);
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return;
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}
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if ((message = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
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log_line("couldnt get option from packet -- ignoring");
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return;
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}
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switch (dhcp_state) {
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case INIT_SELECTING:
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/* Must be a DHCPOFFER to one of our xid's */
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if (*message == DHCPOFFER) {
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if ((temp = get_option(&packet, DHCP_SERVER_ID))) {
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/* Memcpy to a temp buffer to force alignment */
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memcpy(&server_addr, temp, 4);
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xid = packet.xid;
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requested_ip = packet.yiaddr;
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/* enter requesting state */
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dhcp_state = REQUESTING;
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timeout = 0;
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packet_num = 0;
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} else {
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log_line("No server ID in message");
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}
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}
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break;
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case ARP_CHECK:
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/* We ignore dhcp packets for now. This state will
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* be changed by the callback for arp ping.
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*/
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break;
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case RENEW_REQUESTED:
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case REQUESTING:
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case RENEWING:
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case REBINDING:
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if (*message == DHCPACK) {
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if (!(temp = get_option(&packet, DHCP_LEASE_TIME))) {
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log_line("No lease time received, assuming 1h.");
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lease = 60 * 60;
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} else {
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/* Memcpy to a temp buffer to force alignment */
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memcpy(&lease, temp, 4);
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lease = ntohl(lease);
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/* Enforce upper and lower bounds on lease. */
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lease &= 0x0fffffff;
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if (lease < RETRY_DELAY)
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lease = RETRY_DELAY;
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}
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arp_prev_dhcp_state = dhcp_state;
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dhcp_state = ARP_CHECK;
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memcpy(&arp_dhcp_packet, &packet, sizeof packet);
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arpFd = arpping(arp_dhcp_packet.yiaddr, NULL, 0,
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client_config.arp, client_config.interface);
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epoll_add(arpFd);
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timeout = 2000;
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memset(&arpreply, 0, sizeof arpreply);
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arpreply_offset = 0;
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// Can transition to BOUND or INIT_SELECTING.
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} else if (*message == DHCPNAK) {
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/* return to init state */
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log_line("Received DHCP NAK.");
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run_script(&packet, SCRIPT_NAK);
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if (dhcp_state != REQUESTING)
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run_script(NULL, SCRIPT_DECONFIG);
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dhcp_state = INIT_SELECTING;
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timeout = 0;
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requested_ip = 0;
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packet_num = 0;
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change_listen_mode(LISTEN_RAW);
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// XXX: this isn't rfc compliant: should be exp backoff
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sleep(3); /* avoid excessive network traffic */
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}
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break;
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case BOUND:
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case RELEASED:
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default:
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break;
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}
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}
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static void setup_signals()
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{
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sigset_t mask;
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