diff --git a/ndhc/ndhc.c b/ndhc/ndhc.c index ae585c3..da24e07 100644 --- a/ndhc/ndhc.c +++ b/ndhc/ndhc.c @@ -81,21 +81,36 @@ enum { LISTEN_RAW }; -static int epollfd, signalFd, arpFd = -1; -static struct epoll_event events[3]; +struct client_state_t { + unsigned long long leaseStartTime; + int dhcpState; + int arpPrevState; + int listenMode; + int packetNum; + int epollFd, signalFd, listenFd, arpFd; + int timeout; + uint32_t requestedIP, serverAddr; + uint32_t lease, t1, t2, xid; +}; -static char pidfile[MAX_PATH_LENGTH] = PID_FILE_DEFAULT; - -static int timeout; -static uint32_t requested_ip, server_addr; -static uint32_t lease, t1, t2, xid; -static long long start; - -static int dhcp_state = INIT_SELECTING; -static int arp_prev_dhcp_state = DHCP_STATE_NULL; -static int listen_mode = LISTEN_NONE; -static int listenFd = -1; -static int packet_num; +struct client_state_t cs = { + .dhcpState = INIT_SELECTING, + .arpPrevState = DHCP_STATE_NULL, + .listenMode = LISTEN_NONE, + .packetNum = 0, + .xid = 0, + .timeout = 0, + .leaseStartTime = 0, + .requestedIP = 0, + .serverAddr = 0, + .lease = 0, + .t1 = 0, + .t2 = 0, + .epollFd = -1, + .signalFd = -1, + .listenFd = -1, + .arpFd = -1, +}; struct client_config_t client_config = { /* Default options. */ @@ -111,6 +126,8 @@ struct client_config_t client_config = { .arp = "\0", }; +static char pidfile[MAX_PATH_LENGTH] = PID_FILE_DEFAULT; + static unsigned long long curms() { struct timeval tv; @@ -124,7 +141,7 @@ static void epoll_add(int fd) int r; ev.events = EPOLLIN | EPOLLRDHUP | EPOLLERR | EPOLLHUP; ev.data.fd = fd; - r = epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &ev); + r = epoll_ctl(cs.epollFd, EPOLL_CTL_ADD, fd, &ev); if (r == -1) suicide("epoll_add failed %s", strerror(errno)); } @@ -135,7 +152,7 @@ static void epoll_del(int fd) int r; ev.events = EPOLLIN | EPOLLRDHUP | EPOLLERR | EPOLLHUP; ev.data.fd = fd; - r = epoll_ctl(epollfd, EPOLL_CTL_DEL, fd, &ev); + r = epoll_ctl(cs.epollFd, EPOLL_CTL_DEL, fd, &ev); if (r == -1) suicide("epoll_del failed %s", strerror(errno)); } @@ -168,24 +185,24 @@ static void change_listen_mode(int new_mode) { log_line("entering %s listen mode", new_mode ? (new_mode == 1 ? "kernel" : "raw") : "none"); - listen_mode = new_mode; - if (listenFd >= 0) { - epoll_del(listenFd); - close(listenFd); - listenFd = -1; + cs.listenMode = new_mode; + if (cs.listenFd >= 0) { + epoll_del(cs.listenFd); + close(cs.listenFd); + cs.listenFd = -1; } if (new_mode == LISTEN_KERNEL) { - listenFd = listen_socket(INADDR_ANY, CLIENT_PORT, + cs.listenFd = listen_socket(INADDR_ANY, CLIENT_PORT, client_config.interface); - epoll_add(listenFd); + epoll_add(cs.listenFd); } else if (new_mode == LISTEN_RAW) { - listenFd = raw_socket(client_config.ifindex); - epoll_add(listenFd); + cs.listenFd = raw_socket(client_config.ifindex); + epoll_add(cs.listenFd); } else /* LISTEN_NONE */ return; - if (listenFd < 0) { + if (cs.listenFd < 0) { log_error("FATAL: couldn't listen on socket: %s.", strerror(errno)); exit(EXIT_FAILURE); } @@ -196,25 +213,25 @@ static void perform_renew(void) { log_line("Performing a DHCP renew..."); retry: - switch (dhcp_state) { + switch (cs.dhcpState) { case BOUND: change_listen_mode(LISTEN_KERNEL); case ARP_CHECK: // Cancel arp ping in progress and treat as previous state. - epoll_del(arpFd); - arpFd = -1; - dhcp_state = arp_prev_dhcp_state; + epoll_del(cs.arpFd); + cs.arpFd = -1; + cs.dhcpState = cs.arpPrevState; goto retry; case RENEWING: case REBINDING: - dhcp_state = RENEW_REQUESTED; + cs.dhcpState = RENEW_REQUESTED; break; case RENEW_REQUESTED: /* impatient are we? fine, square 1 */ run_script(NULL, SCRIPT_DECONFIG); case REQUESTING: case RELEASED: change_listen_mode(LISTEN_RAW); - dhcp_state = INIT_SELECTING; + cs.dhcpState = INIT_SELECTING; break; case INIT_SELECTING: default: @@ -222,10 +239,10 @@ static void perform_renew(void) } /* start things over */ - packet_num = 0; + cs.packetNum = 0; /* Kill any timeouts because the user wants this to hurry along */ - timeout = 0; + cs.timeout = 0; } @@ -235,24 +252,24 @@ static void perform_release(void) struct in_addr temp_saddr, temp_raddr; /* send release packet */ - if (dhcp_state == BOUND || dhcp_state == RENEWING || - dhcp_state == REBINDING || dhcp_state == ARP_CHECK) { - temp_saddr.s_addr = server_addr; - temp_raddr.s_addr = requested_ip; + if (cs.dhcpState == BOUND || cs.dhcpState == RENEWING || + cs.dhcpState == REBINDING || cs.dhcpState == ARP_CHECK) { + temp_saddr.s_addr = cs.serverAddr; + temp_raddr.s_addr = cs.requestedIP; log_line("Unicasting a release of %s to %s.", inet_ntoa(temp_raddr), inet_ntoa(temp_saddr)); - send_release(server_addr, requested_ip); /* unicast */ + send_release(cs.serverAddr, cs.requestedIP); /* unicast */ run_script(NULL, SCRIPT_DECONFIG); } log_line("Entering released state."); - if (dhcp_state == ARP_CHECK) { - epoll_del(arpFd); - arpFd = -1; + if (cs.dhcpState == ARP_CHECK) { + epoll_del(cs.arpFd); + cs.arpFd = -1; } change_listen_mode(LISTEN_NONE); - dhcp_state = RELEASED; - timeout = -1; + cs.dhcpState = RELEASED; + cs.timeout = -1; } static void background(void) @@ -277,16 +294,16 @@ static struct dhcpMessage arp_dhcp_packet; static void arp_failed(void) { log_line("Offered address is in use: declining."); - epoll_del(arpFd); - arpFd = -1; - send_decline(xid, server_addr, arp_dhcp_packet.yiaddr); + epoll_del(cs.arpFd); + cs.arpFd = -1; + send_decline(cs.xid, cs.serverAddr, arp_dhcp_packet.yiaddr); - if (arp_prev_dhcp_state != REQUESTING) + if (cs.arpPrevState != REQUESTING) run_script(NULL, SCRIPT_DECONFIG); - dhcp_state = INIT_SELECTING; - requested_ip = 0; - timeout = 0; - packet_num = 0; + cs.dhcpState = INIT_SELECTING; + cs.requestedIP = 0; + cs.timeout = 0; + cs.packetNum = 0; change_listen_mode(LISTEN_RAW); } @@ -294,26 +311,26 @@ static void arp_success(void) { struct in_addr temp_addr; - epoll_del(arpFd); - arpFd = -1; + epoll_del(cs.arpFd); + cs.arpFd = -1; /* enter bound state */ - t1 = lease >> 1; + cs.t1 = cs.lease >> 1; /* little fixed point for n * .875 */ - t2 = (lease * 0x7) >> 3; - timeout = t1 * 1000; - start = curms(); + cs.t2 = (cs.lease * 0x7) >> 3; + cs.timeout = cs.t1 * 1000; + cs.leaseStartTime = curms(); temp_addr.s_addr = arp_dhcp_packet.yiaddr; log_line("Lease of %s obtained, lease time %ld.", - inet_ntoa(temp_addr), lease); - requested_ip = arp_dhcp_packet.yiaddr; + inet_ntoa(temp_addr), cs.lease); + cs.requestedIP = arp_dhcp_packet.yiaddr; run_script(&arp_dhcp_packet, - ((arp_prev_dhcp_state == RENEWING || - arp_prev_dhcp_state == REBINDING) + ((cs.arpPrevState == RENEWING || + cs.arpPrevState == REBINDING) ? SCRIPT_RENEW : SCRIPT_BOUND)); - dhcp_state = BOUND; + cs.dhcpState = BOUND; change_listen_mode(LISTEN_NONE); if (client_config.quit_after_lease) exit(EXIT_SUCCESS); @@ -323,14 +340,14 @@ static void arp_success(void) static void init_selecting_timeout() { - if (packet_num < NUMPACKETS) { - if (packet_num == 0) - xid = random_xid(); + if (cs.packetNum < NUMPACKETS) { + if (cs.packetNum == 0) + cs.xid = random_xid(); /* broadcast */ - send_discover(xid, requested_ip); + send_discover(cs.xid, cs.requestedIP); - timeout = ((packet_num == NUMPACKETS - 1) ? 4 : 2) * 1000; - packet_num++; + cs.timeout = ((cs.packetNum == NUMPACKETS - 1) ? 4 : 2) * 1000; + cs.packetNum++; } else { if (client_config.background_if_no_lease) { log_line("No lease, going to background."); @@ -340,40 +357,40 @@ static void init_selecting_timeout() exit(EXIT_FAILURE); } /* wait to try again */ - packet_num = 0; - timeout = RETRY_DELAY * 1000; + cs.packetNum = 0; + cs.timeout = RETRY_DELAY * 1000; } } static void renew_requested_timeout() { - if (packet_num < NUMPACKETS) { + if (cs.packetNum < NUMPACKETS) { /* send unicast request packet */ - send_renew(xid, server_addr, requested_ip); - timeout = ((packet_num == NUMPACKETS - 1) ? 10 : 2) * 1000; - packet_num++; + send_renew(cs.xid, cs.serverAddr, cs.requestedIP); + cs.timeout = ((cs.packetNum == NUMPACKETS - 1) ? 10 : 2) * 1000; + cs.packetNum++; } else { /* timed out, go back to init state */ run_script(NULL, SCRIPT_DECONFIG); - dhcp_state = INIT_SELECTING; - timeout = 0; - packet_num = 0; + cs.dhcpState = INIT_SELECTING; + cs.timeout = 0; + cs.packetNum = 0; change_listen_mode(LISTEN_RAW); } } static void requesting_timeout() { - if (packet_num < NUMPACKETS) { + if (cs.packetNum < NUMPACKETS) { /* send broadcast request packet */ - send_selecting(xid, server_addr, requested_ip); - timeout = ((packet_num == NUMPACKETS - 1) ? 10 : 2) * 1000; - packet_num++; + send_selecting(cs.xid, cs.serverAddr, cs.requestedIP); + cs.timeout = ((cs.packetNum == NUMPACKETS - 1) ? 10 : 2) * 1000; + cs.packetNum++; } else { /* timed out, go back to init state */ - dhcp_state = INIT_SELECTING; - timeout = 0; - packet_num = 0; + cs.dhcpState = INIT_SELECTING; + cs.timeout = 0; + cs.packetNum = 0; change_listen_mode(LISTEN_RAW); } } @@ -381,24 +398,24 @@ static void requesting_timeout() static void renewing_timeout() { /* Either set a new T1, or enter REBINDING state */ - if ((t2 - t1) <= (lease / 14400 + 1)) { + if ((cs.t2 - cs.t1) <= (cs.lease / 14400 + 1)) { /* timed out, enter rebinding state */ - dhcp_state = REBINDING; - timeout = (t2 - t1) * 1000; + cs.dhcpState = REBINDING; + cs.timeout = (cs.t2 - cs.t1) * 1000; log_line("Entering rebinding state."); } else { /* send a request packet */ - send_renew(xid, server_addr, requested_ip); /* unicast */ + send_renew(cs.xid, cs.serverAddr, cs.requestedIP); /* unicast */ - t1 = ((t2 - t1) >> 1) + t1; - timeout = (t1 * 1000) - (curms() - start); + cs.t1 = ((cs.t2 - cs.t1) >> 1) + cs.t1; + cs.timeout = (cs.t1 * 1000) - (curms() - cs.leaseStartTime); } } static void bound_timeout() { /* Lease is starting to run out, time to enter renewing state */ - dhcp_state = RENEWING; + cs.dhcpState = RENEWING; change_listen_mode(LISTEN_KERNEL); log_line("Entering renew state."); renewing_timeout(); @@ -407,34 +424,34 @@ static void bound_timeout() static void rebinding_timeout() { /* Either set a new T2, or enter INIT state */ - if ((lease - t2) <= (lease / 14400 + 1)) { + if ((cs.lease - cs.t2) <= (cs.lease / 14400 + 1)) { /* timed out, enter init state */ - dhcp_state = INIT_SELECTING; + cs.dhcpState = INIT_SELECTING; log_line("Lease lost, entering init state."); run_script(NULL, SCRIPT_DECONFIG); - timeout = 0; - packet_num = 0; + cs.timeout = 0; + cs.packetNum = 0; change_listen_mode(LISTEN_RAW); } else { /* send a request packet */ - send_renew(xid, 0, requested_ip); /* broadcast */ + send_renew(cs.xid, 0, cs.requestedIP); /* broadcast */ - t2 = ((lease - t2) >> 1) + t2; - timeout = (t2 * 1000) - (curms() - start); + cs.t2 = ((cs.lease - cs.t2) >> 1) + cs.t2; + cs.timeout = (cs.t2 * 1000) - (curms() - cs.leaseStartTime); } } /* Handle epoll timeout expiring */ static void handle_timeout(void) { - switch (dhcp_state) { + switch (cs.dhcpState) { case INIT_SELECTING: init_selecting_timeout(); break; case RENEW_REQUESTED: renew_requested_timeout(); break; case REQUESTING: requesting_timeout(); break; case RENEWING: renewing_timeout(); break; case BOUND: bound_timeout(); break; case REBINDING: rebinding_timeout(); break; - case RELEASED: timeout = -1; break; + case RELEASED: cs.timeout = -1; break; case ARP_CHECK: arp_success(); break; default: break; } @@ -448,14 +465,14 @@ static void init_selecting_packet(struct dhcpMessage *packet, if (*message == DHCPOFFER) { if ((temp = get_option(packet, DHCP_SERVER_ID))) { /* Memcpy to a temp buffer to force alignment */ - memcpy(&server_addr, temp, 4); - xid = packet->xid; - requested_ip = packet->yiaddr; + memcpy(&cs.serverAddr, temp, 4); + cs.xid = packet->xid; + cs.requestedIP = packet->yiaddr; /* enter requesting state */ - dhcp_state = REQUESTING; - timeout = 0; - packet_num = 0; + cs.dhcpState = REQUESTING; + cs.timeout = 0; + cs.packetNum = 0; } else { log_line("No server ID in message"); } @@ -469,24 +486,24 @@ static void dhcp_ack_or_nak_packet(struct dhcpMessage *packet, if (*message == DHCPACK) { if (!(temp = get_option(packet, DHCP_LEASE_TIME))) { log_line("No lease time received, assuming 1h."); - lease = 60 * 60; + cs.lease = 60 * 60; } else { /* Memcpy to a temp buffer to force alignment */ - memcpy(&lease, temp, 4); - lease = ntohl(lease); + memcpy(&cs.lease, temp, 4); + cs.lease = ntohl(cs.lease); /* Enforce upper and lower bounds on lease. */ - lease &= 0x0fffffff; - if (lease < RETRY_DELAY) - lease = RETRY_DELAY; + cs.lease &= 0x0fffffff; + if (cs.lease < RETRY_DELAY) + cs.lease = RETRY_DELAY; } - arp_prev_dhcp_state = dhcp_state; - dhcp_state = ARP_CHECK; + cs.arpPrevState = cs.dhcpState; + cs.dhcpState = ARP_CHECK; memcpy(&arp_dhcp_packet, packet, sizeof (struct dhcpMessage)); - arpFd = arpping(arp_dhcp_packet.yiaddr, NULL, 0, + cs.arpFd = arpping(arp_dhcp_packet.yiaddr, NULL, 0, client_config.arp, client_config.interface); - epoll_add(arpFd); - timeout = 2000; + epoll_add(cs.arpFd); + cs.timeout = 2000; memset(&arpreply, 0, sizeof arpreply); arpreply_offset = 0; // Can transition to BOUND or INIT_SELECTING. @@ -495,12 +512,12 @@ static void dhcp_ack_or_nak_packet(struct dhcpMessage *packet, /* return to init state */ log_line("Received DHCP NAK."); run_script(packet, SCRIPT_NAK); - if (dhcp_state != REQUESTING) + if (cs.dhcpState != REQUESTING) run_script(NULL, SCRIPT_DECONFIG); - dhcp_state = INIT_SELECTING; - timeout = 0; - requested_ip = 0; - packet_num = 0; + cs.dhcpState = INIT_SELECTING; + cs.timeout = 0; + cs.requestedIP = 0; + cs.packetNum = 0; change_listen_mode(LISTEN_RAW); // XXX: this isn't rfc compliant: should be exp backoff sleep(3); /* avoid excessive network traffic */ @@ -513,24 +530,24 @@ static void handle_packet(void) int len; struct dhcpMessage packet; - if (listen_mode == LISTEN_KERNEL) - len = get_packet(&packet, listenFd); - else if (listen_mode == LISTEN_RAW) - len = get_raw_packet(&packet, listenFd); + if (cs.listenMode == LISTEN_KERNEL) + len = get_packet(&packet, cs.listenFd); + else if (cs.listenMode == LISTEN_RAW) + len = get_raw_packet(&packet, cs.listenFd); else /* LISTEN_NONE */ return; if (len == -1 && errno != EINTR) { log_error("reopening socket."); - change_listen_mode(listen_mode); /* just close and reopen */ + change_listen_mode(cs.listenMode); /* just close and reopen */ } if (len < 0) return; - if (packet.xid != xid) { + if (packet.xid != cs.xid) { log_line("Ignoring XID %lx (our xid is %lx).", - (uint32_t) packet.xid, xid); + (uint32_t) packet.xid, cs.xid); return; } @@ -539,7 +556,7 @@ static void handle_packet(void) return; } - switch (dhcp_state) { + switch (cs.dhcpState) { case INIT_SELECTING: init_selecting_packet(&packet, message); break; @@ -565,7 +582,7 @@ typedef uint32_t aliased_uint32_t __attribute__((__may_alias__)); static void handle_arp_response(void) { if (arpreply_offset < sizeof arpreply) { - int r = safe_read(arpFd, (char *)&arpreply + arpreply_offset, + int r = safe_read(cs.arpFd, (char *)&arpreply + arpreply_offset, sizeof arpreply - arpreply_offset); if (r < 0) { arp_failed(); @@ -607,8 +624,8 @@ static void setup_signals() sigaddset(&mask, SIGTERM); if (sigprocmask(SIG_BLOCK, &mask, NULL) < 0) suicide("sigprocmask failed"); - signalFd = signalfd(-1, &mask, SFD_NONBLOCK); - if (signalFd < 0) + cs.signalFd = signalfd(-1, &mask, SFD_NONBLOCK); + if (cs.signalFd < 0) suicide("signalfd failed"); } @@ -617,7 +634,7 @@ static void signal_dispatch() int t, off = 0; struct signalfd_siginfo si; again: - t = read(signalFd, (char *)&si + off, sizeof si - off); + t = read(cs.signalFd, (char *)&si + off, sizeof si - off); if (t < sizeof si - off) { if (t < 0) { if (t == EAGAIN || t == EWOULDBLOCK || t == EINTR) @@ -644,19 +661,20 @@ static void signal_dispatch() static void do_work(void) { + struct epoll_event events[3]; long long last_awake; int timeout_delta; - epollfd = epoll_create1(0); - if (epollfd == -1) + cs.epollFd = epoll_create1(0); + if (cs.epollFd == -1) suicide("epoll_create1 failed"); - epoll_add(signalFd); + epoll_add(cs.signalFd); change_listen_mode(LISTEN_RAW); handle_timeout(); for (;;) { last_awake = curms(); - int r = epoll_wait(epollfd, events, 3, timeout); + int r = epoll_wait(cs.epollFd, events, 3, cs.timeout); if (r == -1) { if (errno == EINTR) continue; @@ -665,20 +683,20 @@ static void do_work(void) } for (int i = 0; i < r; ++i) { int fd = events[i].data.fd; - if (fd == signalFd) + if (fd == cs.signalFd) signal_dispatch(); - else if (fd == listenFd) + else if (fd == cs.listenFd) handle_packet(); - else if (fd == arpFd) + else if (fd == cs.arpFd) handle_arp_response(); else suicide("epoll_wait: unknown fd"); } timeout_delta = curms() - last_awake; - timeout -= timeout_delta; - if (timeout <= 0) { - timeout = 0; + cs.timeout -= timeout_delta; + if (cs.timeout <= 0) { + cs.timeout = 0; handle_timeout(); } } @@ -759,7 +777,7 @@ int main(int argc, char **argv) client_config.quit_after_lease = 1; break; case 'r': - requested_ip = inet_addr(optarg); + cs.requestedIP = inet_addr(optarg); break; case 'u': pwd = getpwnam(optarg);