/*** This file is part of systemd. Copyright (C) 2013 Intel Corporation. All rights reserved. systemd is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. systemd 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with systemd; If not, see . ***/ #include #include #include #include #include #include #include #include #include "util.h" #include "list.h" #include "refcnt.h" #include "dhcp-protocol.h" #include "dhcp-internal.h" #include "dhcp-lease-internal.h" #include "sd-dhcp-client.h" struct sd_dhcp_client { RefCount n_ref; DHCPState state; sd_event *event; int event_priority; sd_event_source *timeout_resend; int index; int fd; union sockaddr_union link; sd_event_source *receive_message; uint8_t *req_opts; size_t req_opts_allocated; size_t req_opts_size; be32_t last_addr; struct { uint8_t type; struct ether_addr mac_addr; } _packed_ client_id; uint32_t xid; usec_t start_time; uint16_t secs; unsigned int attempt; usec_t request_sent; sd_event_source *timeout_t1; sd_event_source *timeout_t2; sd_event_source *timeout_expire; sd_dhcp_client_cb_t cb; void *userdata; sd_dhcp_lease *lease; }; static const uint8_t default_req_opts[] = { DHCP_OPTION_SUBNET_MASK, DHCP_OPTION_ROUTER, DHCP_OPTION_HOST_NAME, DHCP_OPTION_DOMAIN_NAME, DHCP_OPTION_DOMAIN_NAME_SERVER, DHCP_OPTION_NTP_SERVER, }; static int client_receive_message_raw(sd_event_source *s, int fd, uint32_t revents, void *userdata); static int client_receive_message_udp(sd_event_source *s, int fd, uint32_t revents, void *userdata); static sd_dhcp_client *client_stop(sd_dhcp_client *client, int error); int sd_dhcp_client_set_callback(sd_dhcp_client *client, sd_dhcp_client_cb_t cb, void *userdata) { assert_return(client, -EINVAL); client->cb = cb; client->userdata = userdata; return 0; } int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option) { size_t i; assert_return(client, -EINVAL); assert_return (IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_STOPPED), -EBUSY); switch(option) { case DHCP_OPTION_PAD: case DHCP_OPTION_OVERLOAD: case DHCP_OPTION_MESSAGE_TYPE: case DHCP_OPTION_PARAMETER_REQUEST_LIST: case DHCP_OPTION_END: return -EINVAL; default: break; } for (i = 0; i < client->req_opts_size; i++) if (client->req_opts[i] == option) return -EEXIST; if (!GREEDY_REALLOC(client->req_opts, client->req_opts_allocated, client->req_opts_size + 1)) return -ENOMEM; client->req_opts[client->req_opts_size++] = option; return 0; } int sd_dhcp_client_set_request_address(sd_dhcp_client *client, const struct in_addr *last_addr) { assert_return(client, -EINVAL); assert_return (IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_STOPPED), -EBUSY); if (last_addr) client->last_addr = last_addr->s_addr; else client->last_addr = INADDR_ANY; return 0; } int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index) { assert_return(client, -EINVAL); assert_return (IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_STOPPED), -EBUSY); assert_return(interface_index >= -1, -EINVAL); client->index = interface_index; return 0; } int sd_dhcp_client_set_mac(sd_dhcp_client *client, const struct ether_addr *addr) { bool need_restart = false; assert_return(client, -EINVAL); assert_return(addr, -EINVAL); if (memcmp(&client->client_id.mac_addr, addr, ETH_ALEN) == 0) return 0; if (!IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_STOPPED)) { log_dhcp_client(client, "Changing MAC address on running DHCP " "client, restarting"); need_restart = true; client = client_stop(client, DHCP_EVENT_STOP); } if (!client) return 0; memcpy(&client->client_id.mac_addr, addr, ETH_ALEN); client->client_id.type = 0x01; if (need_restart && client->state != DHCP_STATE_STOPPED) sd_dhcp_client_start(client); return 0; } int sd_dhcp_client_get_lease(sd_dhcp_client *client, sd_dhcp_lease **ret) { assert_return(client, -EINVAL); assert_return(ret, -EINVAL); if (client->state != DHCP_STATE_BOUND && client->state != DHCP_STATE_RENEWING && client->state != DHCP_STATE_REBINDING) return -EADDRNOTAVAIL; *ret = sd_dhcp_lease_ref(client->lease); return 0; } static sd_dhcp_client *client_notify(sd_dhcp_client *client, int event) { if (client->cb) { client = sd_dhcp_client_ref(client); client->cb(client, event, client->userdata); client = sd_dhcp_client_unref(client); } return client; } static int client_initialize(sd_dhcp_client *client) { assert_return(client, -EINVAL); client->receive_message = sd_event_source_unref(client->receive_message); client->fd = safe_close(client->fd); client->timeout_resend = sd_event_source_unref(client->timeout_resend); client->timeout_t1 = sd_event_source_unref(client->timeout_t1); client->timeout_t2 = sd_event_source_unref(client->timeout_t2); client->timeout_expire = sd_event_source_unref(client->timeout_expire); client->attempt = 1; client->state = DHCP_STATE_INIT; client->xid = 0; if (client->lease) client->lease = sd_dhcp_lease_unref(client->lease); return 0; } static sd_dhcp_client *client_stop(sd_dhcp_client *client, int error) { assert_return(client, NULL); log_dhcp_client(client, "STOPPED %d", error); client = client_notify(client, error); if (client) client_initialize(client); return client; } static int client_message_init(sd_dhcp_client *client, DHCPMessage *message, uint8_t type, uint8_t **opt, size_t *optlen) { int r; assert(client); assert(client->secs); assert(message); assert(opt); assert(optlen); r = dhcp_message_init(message, BOOTREQUEST, client->xid, type, opt, optlen); if (r < 0) return r; /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers refuse to issue an DHCP lease if 'secs' is set to zero */ message->secs = htobe16(client->secs); memcpy(&message->chaddr, &client->client_id.mac_addr, ETH_ALEN); if (client->state == DHCP_STATE_RENEWING || client->state == DHCP_STATE_REBINDING) message->ciaddr = client->lease->address; /* Some DHCP servers will refuse to issue an DHCP lease if the Client Identifier option is not set */ r = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER, sizeof(client->client_id), &client->client_id); if (r < 0) return r; if (type == DHCP_DISCOVER || type == DHCP_REQUEST) { be16_t max_size; r = dhcp_option_append(opt, optlen, DHCP_OPTION_PARAMETER_REQUEST_LIST, client->req_opts_size, client->req_opts); if (r < 0) return r; /* Some DHCP servers will send bigger DHCP packets than the defined default size unless the Maximum Messge Size option is explicitely set */ max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE + DHCP_MIN_OPTIONS_SIZE); r = dhcp_option_append(opt, optlen, DHCP_OPTION_MAXIMUM_MESSAGE_SIZE, 2, &max_size); if (r < 0) return r; } return 0; } static int dhcp_client_send_raw(sd_dhcp_client *client, DHCPPacket *packet, size_t len) { dhcp_packet_append_ip_headers(packet, INADDR_ANY, DHCP_PORT_CLIENT, INADDR_BROADCAST, DHCP_PORT_SERVER, len); return dhcp_network_send_raw_socket(client->fd, &client->link, packet, len); } static int client_send_discover(sd_dhcp_client *client) { _cleanup_free_ DHCPPacket *discover = NULL; size_t optlen, len; uint8_t *opt; usec_t time_now; int r; assert(client); r = sd_event_now(client->event, CLOCK_MONOTONIC, &time_now); if (r < 0) return r; assert(time_now >= client->start_time); /* seconds between sending first and last DISCOVER * must always be strictly positive to deal with broken servers */ client->secs = ((time_now - client->start_time) / USEC_PER_SEC) ? : 1; optlen = DHCP_MIN_OPTIONS_SIZE; len = sizeof(DHCPPacket) + optlen; discover = malloc0(len); if (!discover) return -ENOMEM; r = client_message_init(client, &discover->dhcp, DHCP_DISCOVER, &opt, &optlen); if (r < 0) return r; if (client->last_addr != INADDR_ANY) { r = dhcp_option_append(&opt, &optlen, DHCP_OPTION_REQUESTED_IP_ADDRESS, 4, &client->last_addr); if (r < 0) return r; } r = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL); if (r < 0) return r; r = dhcp_client_send_raw(client, discover, len - optlen); if (r < 0) return r; log_dhcp_client(client, "DISCOVER"); return 0; } static int client_send_request(sd_dhcp_client *client) { _cleanup_free_ DHCPPacket *request; size_t optlen, len; uint8_t *opt; int r; optlen = DHCP_MIN_OPTIONS_SIZE; len = sizeof(DHCPPacket) + optlen; request = malloc0(len); if (!request) return -ENOMEM; r = client_message_init(client, &request->dhcp, DHCP_REQUEST, &opt, &optlen); if (r < 0) return r; switch (client->state) { case DHCP_STATE_INIT_REBOOT: r = dhcp_option_append(&opt, &optlen, DHCP_OPTION_REQUESTED_IP_ADDRESS, 4, &client->last_addr); if (r < 0) return r; break; case DHCP_STATE_REQUESTING: r = dhcp_option_append(&opt, &optlen, DHCP_OPTION_REQUESTED_IP_ADDRESS, 4, &client->lease->address); if (r < 0) return r; r = dhcp_option_append(&opt, &optlen, DHCP_OPTION_SERVER_IDENTIFIER, 4, &client->lease->server_address); if (r < 0) return r; break; case DHCP_STATE_INIT: case DHCP_STATE_SELECTING: case DHCP_STATE_REBOOTING: case DHCP_STATE_BOUND: case DHCP_STATE_RENEWING: case DHCP_STATE_REBINDING: break; case DHCP_STATE_STOPPED: return -EINVAL; } r = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL); if (r < 0) return r; if (client->state == DHCP_STATE_RENEWING) { r = dhcp_network_send_udp_socket(client->fd, client->lease->server_address, DHCP_PORT_SERVER, &request->dhcp, len - optlen - DHCP_IP_UDP_SIZE); } else { r = dhcp_client_send_raw(client, request, len - optlen); } if (r < 0) return r; log_dhcp_client(client, "REQUEST"); return 0; } static int client_timeout_resend(sd_event_source *s, uint64_t usec, void *userdata) { sd_dhcp_client *client = userdata; usec_t next_timeout = 0; uint64_t time_now; uint32_t time_left; int r; assert(s); assert(client); assert(client->event); r = sd_event_now(client->event, CLOCK_MONOTONIC, &time_now); if (r < 0) goto error; switch (client->state) { case DHCP_STATE_RENEWING: time_left = (client->lease->t2 - client->lease->t1) / 2; if (time_left < 60) time_left = 60; next_timeout = time_now + time_left * USEC_PER_SEC; break; case DHCP_STATE_REBINDING: time_left = (client->lease->lifetime - client->lease->t2) / 2; if (time_left < 60) time_left = 60; next_timeout = time_now + time_left * USEC_PER_SEC; break; case DHCP_STATE_REBOOTING: /* start over as we did not receive a timely ack or nak */ client->state = DHCP_STATE_INIT; client->attempt = 1; client->xid = random_u32(); /* fall through */ case DHCP_STATE_INIT: case DHCP_STATE_INIT_REBOOT: case DHCP_STATE_SELECTING: case DHCP_STATE_REQUESTING: case DHCP_STATE_BOUND: if (client->attempt < 64) client->attempt *= 2; next_timeout = time_now + (client->attempt - 1) * USEC_PER_SEC; break; case DHCP_STATE_STOPPED: r = -EINVAL; goto error; } next_timeout += (random_u32() & 0x1fffff); client->timeout_resend = sd_event_source_unref(client->timeout_resend); r = sd_event_add_time(client->event, &client->timeout_resend, CLOCK_MONOTONIC, next_timeout, 10 * USEC_PER_MSEC, client_timeout_resend, client); if (r < 0) goto error; r = sd_event_source_set_priority(client->timeout_resend, client->event_priority); if (r < 0) goto error; switch (client->state) { case DHCP_STATE_INIT: r = client_send_discover(client); if (r >= 0) { client->state = DHCP_STATE_SELECTING; client->attempt = 1; } else { if (client->attempt >= 64) goto error; } break; case DHCP_STATE_SELECTING: r = client_send_discover(client); if (r < 0 && client->attempt >= 64) goto error; break; case DHCP_STATE_INIT_REBOOT: case DHCP_STATE_REQUESTING: case DHCP_STATE_RENEWING: case DHCP_STATE_REBINDING: r = client_send_request(client); if (r < 0 && client->attempt >= 64) goto error; if (client->state == DHCP_STATE_INIT_REBOOT) client->state = DHCP_STATE_REBOOTING; client->request_sent = time_now; break; case DHCP_STATE_REBOOTING: case DHCP_STATE_BOUND: break; case DHCP_STATE_STOPPED: r = -EINVAL; goto error; } return 0; error: client_stop(client, r); /* Errors were dealt with when stopping the client, don't spill errors into the event loop handler */ return 0; } static int client_initialize_events(sd_dhcp_client *client, sd_event_io_handler_t io_callback) { int r; assert(client); assert(client->event); r = sd_event_add_io(client->event, &client->receive_message, client->fd, EPOLLIN, io_callback, client); if (r < 0) goto error; r = sd_event_source_set_priority(client->receive_message, client->event_priority); if (r < 0) goto error; client->timeout_resend = sd_event_source_unref(client->timeout_resend); r = sd_event_add_time(client->event, &client->timeout_resend, CLOCK_MONOTONIC, 0, 0, client_timeout_resend, client); if (r < 0) goto error; r = sd_event_source_set_priority(client->timeout_resend, client->event_priority); error: if (r < 0) client_stop(client, r); return 0; } static int client_start(sd_dhcp_client *client) { int r; assert_return(client, -EINVAL); assert_return(client->event, -EINVAL); assert_return(client->index > 0, -EINVAL); assert_return(client->fd < 0, -EBUSY); assert_return(client->xid == 0, -EINVAL); assert_return(client->state == DHCP_STATE_INIT || client->state == DHCP_STATE_INIT_REBOOT, -EBUSY); client->xid = random_u32(); r = dhcp_network_bind_raw_socket(client->index, &client->link, client->xid); if (r < 0) { client_stop(client, r); return r; } client->fd = r; if (client->state == DHCP_STATE_INIT) { client->start_time = now(CLOCK_MONOTONIC); client->secs = 0; } log_dhcp_client(client, "STARTED"); return client_initialize_events(client, client_receive_message_raw); } static int client_timeout_expire(sd_event_source *s, uint64_t usec, void *userdata) { sd_dhcp_client *client = userdata; log_dhcp_client(client, "EXPIRED"); client = client_notify(client, DHCP_EVENT_EXPIRED); /* lease was lost, start over if not freed or stopped in callback */ if (client && client->state != DHCP_STATE_STOPPED) { client_initialize(client); client_start(client); } return 0; } static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) { sd_dhcp_client *client = userdata; int r; client->receive_message = sd_event_source_unref(client->receive_message); client->fd = safe_close(client->fd); client->state = DHCP_STATE_REBINDING; client->attempt = 1; r = dhcp_network_bind_raw_socket(client->index, &client->link, client->xid); if (r < 0) { client_stop(client, r); return 0; } client->fd = r; log_dhcp_client(client, "TIMEOUT T2"); return client_initialize_events(client, client_receive_message_raw); } static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata) { sd_dhcp_client *client = userdata; int r; client->state = DHCP_STATE_RENEWING; client->attempt = 1; r = dhcp_network_bind_udp_socket(client->index, client->lease->address, DHCP_PORT_CLIENT); if (r < 0) { client_stop(client, r); return 0; } client->fd = r; log_dhcp_client(client, "TIMEOUT T1"); return client_initialize_events(client, client_receive_message_udp); } static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer, size_t len) { _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL; int r; r = dhcp_lease_new(&lease); if (r < 0) return r; r = dhcp_option_parse(offer, len, dhcp_lease_parse_options, lease); if (r != DHCP_OFFER) { log_dhcp_client(client, "receieved message was not an OFFER, ignoring"); return -ENOMSG; } lease->next_server = offer->siaddr; lease->address = offer->yiaddr; if (lease->address == INADDR_ANY || lease->server_address == INADDR_ANY || lease->lifetime == 0) { log_dhcp_client(client, "receieved lease lacks address, server " "address or lease lifetime, ignoring"); return -ENOMSG; } if (lease->subnet_mask == INADDR_ANY) { r = dhcp_lease_set_default_subnet_mask(lease); if (r < 0) { log_dhcp_client(client, "receieved lease lacks subnet " "mask, and a fallback one can not be " "generated, ignoring"); return -ENOMSG; } } client->lease = lease; lease = NULL; log_dhcp_client(client, "OFFER"); return 0; } static int client_handle_ack(sd_dhcp_client *client, DHCPMessage *ack, size_t len) { _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL; int r; r = dhcp_lease_new(&lease); if (r < 0) return r; r = dhcp_option_parse(ack, len, dhcp_lease_parse_options, lease); if (r == DHCP_NAK) { log_dhcp_client(client, "NAK"); return DHCP_EVENT_NO_LEASE; } if (r != DHCP_ACK) { log_dhcp_client(client, "receieved message was not an ACK, ignoring"); return -ENOMSG; } lease->next_server = ack->siaddr; lease->address = ack->yiaddr; if (lease->address == INADDR_ANY || lease->server_address == INADDR_ANY || lease->lifetime == 0) { log_dhcp_client(client, "receieved lease lacks address, server " "address or lease lifetime, ignoring"); return -ENOMSG; } if (lease->subnet_mask == INADDR_ANY) { r = dhcp_lease_set_default_subnet_mask(lease); if (r < 0) { log_dhcp_client(client, "receieved lease lacks subnet " "mask, and a fallback one can not be " "generated, ignoring"); return -ENOMSG; } } r = DHCP_EVENT_IP_ACQUIRE; if (client->lease) { if (client->lease->address != lease->address || client->lease->subnet_mask != lease->subnet_mask || client->lease->router != lease->router) { r = DHCP_EVENT_IP_CHANGE; } client->lease = sd_dhcp_lease_unref(client->lease); } client->lease = lease; lease = NULL; log_dhcp_client(client, "ACK"); return r; } static uint64_t client_compute_timeout(sd_dhcp_client *client, uint32_t lifetime, double factor) { assert(client); assert(client->request_sent); assert(lifetime); return client->request_sent + ((lifetime - 3) * USEC_PER_SEC * factor) + + (random_u32() & 0x1fffff); } static int client_set_lease_timeouts(sd_dhcp_client *client) { usec_t time_now; uint64_t lifetime_timeout; uint64_t t2_timeout; uint64_t t1_timeout; char time_string[FORMAT_TIMESPAN_MAX]; int r; assert(client); assert(client->event); assert(client->lease); assert(client->lease->lifetime); client->timeout_t1 = sd_event_source_unref(client->timeout_t1); client->timeout_t2 = sd_event_source_unref(client->timeout_t2); client->timeout_expire = sd_event_source_unref(client->timeout_expire); /* don't set timers for infinite leases */ if (client->lease->lifetime == 0xffffffff) return 0; r = sd_event_now(client->event, CLOCK_MONOTONIC, &time_now); if (r < 0) return r; assert(client->request_sent <= time_now); /* convert the various timeouts from relative (secs) to absolute (usecs) */ lifetime_timeout = client_compute_timeout(client, client->lease->lifetime, 1); if (client->lease->t1 && client->lease->t2) { /* both T1 and T2 are given */ if (client->lease->t1 < client->lease->t2 && client->lease->t2 < client->lease->lifetime) { /* they are both valid */ t2_timeout = client_compute_timeout(client, client->lease->t2, 1); t1_timeout = client_compute_timeout(client, client->lease->t1, 1); } else { /* discard both */ t2_timeout = client_compute_timeout(client, client->lease->lifetime, 7.0 / 8.0); client->lease->t2 = (client->lease->lifetime * 7) / 8; t1_timeout = client_compute_timeout(client, client->lease->lifetime, 0.5); client->lease->t1 = client->lease->lifetime / 2; } } else if (client->lease->t2 && client->lease->t2 < client->lease->lifetime) { /* only T2 is given, and it is valid */ t2_timeout = client_compute_timeout(client, client->lease->t2, 1); t1_timeout = client_compute_timeout(client, client->lease->lifetime, 0.5); client->lease->t1 = client->lease->lifetime / 2; if (t2_timeout <= t1_timeout) { /* the computed T1 would be invalid, so discard T2 */ t2_timeout = client_compute_timeout(client, client->lease->lifetime, 7.0 / 8.0); client->lease->t2 = (client->lease->lifetime * 7) / 8; } } else if (client->lease->t1 && client->lease->t1 < client->lease->lifetime) { /* only T1 is given, and it is valid */ t1_timeout = client_compute_timeout(client, client->lease->t1, 1); t2_timeout = client_compute_timeout(client, client->lease->lifetime, 7.0 / 8.0); client->lease->t2 = (client->lease->lifetime * 7) / 8; if (t2_timeout <= t1_timeout) { /* the computed T2 would be invalid, so discard T1 */ t2_timeout = client_compute_timeout(client, client->lease->lifetime, 0.5); client->lease->t2 = client->lease->lifetime / 2; } } else { /* fall back to the default timeouts */ t1_timeout = client_compute_timeout(client, client->lease->lifetime, 0.5); client->lease->t1 = client->lease->lifetime / 2; t2_timeout = client_compute_timeout(client, client->lease->lifetime, 7.0 / 8.0); client->lease->t2 = (client->lease->lifetime * 7) / 8; } /* arm lifetime timeout */ r = sd_event_add_time(client->event, &client->timeout_expire, CLOCK_MONOTONIC, lifetime_timeout, 10 * USEC_PER_MSEC, client_timeout_expire, client); if (r < 0) return r; r = sd_event_source_set_priority(client->timeout_expire, client->event_priority); if (r < 0) return r; log_dhcp_client(client, "lease expires in %s", format_timespan(time_string, FORMAT_TIMESPAN_MAX, lifetime_timeout - time_now, 0)); /* don't arm earlier timeouts if this has already expired */ if (lifetime_timeout <= time_now) return 0; /* arm T2 timeout */ r = sd_event_add_time(client->event, &client->timeout_t2, CLOCK_MONOTONIC, t2_timeout, 10 * USEC_PER_MSEC, client_timeout_t2, client); if (r < 0) return r; r = sd_event_source_set_priority(client->timeout_t2, client->event_priority); if (r < 0) return r; log_dhcp_client(client, "T2 expires in %s", format_timespan(time_string, FORMAT_TIMESPAN_MAX, t2_timeout - time_now, 0)); /* don't arm earlier timeout if this has already expired */ if (t2_timeout <= time_now) return 0; /* arm T1 timeout */ r = sd_event_add_time(client->event, &client->timeout_t1, CLOCK_MONOTONIC, t1_timeout, 10 * USEC_PER_MSEC, client_timeout_t1, client); if (r < 0) return r; r = sd_event_source_set_priority(client->timeout_t1, client->event_priority); if (r < 0) return r; log_dhcp_client(client, "T1 expires in %s", format_timespan(time_string, FORMAT_TIMESPAN_MAX, t1_timeout - time_now, 0)); return 0; } static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message, int len) { int r = 0, notify_event = 0; assert(client); assert(client->event); assert(message); if (be32toh(message->magic) != DHCP_MAGIC_COOKIE) { log_dhcp_client(client, "not a DHCP message: ignoring"); return 0; } if (message->op != BOOTREPLY) { log_dhcp_client(client, "not a BOOTREPLY message: ignoring"); return 0; } if (be32toh(message->xid) != client->xid) { log_dhcp_client(client, "received xid (%u) does not match " "expected (%u): ignoring", be32toh(message->xid), client->xid); return 0; } if (message->htype != ARPHRD_ETHER || message->hlen != ETHER_ADDR_LEN) { log_dhcp_client(client, "not an ethernet packet"); return 0; } if (memcmp(&message->chaddr[0], &client->client_id.mac_addr, ETH_ALEN)) { log_dhcp_client(client, "received chaddr does not match " "expected: ignoring"); return 0; } switch (client->state) { case DHCP_STATE_SELECTING: r = client_handle_offer(client, message, len); if (r >= 0) { client->timeout_resend = sd_event_source_unref(client->timeout_resend); client->state = DHCP_STATE_REQUESTING; client->attempt = 1; r = sd_event_add_time(client->event, &client->timeout_resend, CLOCK_MONOTONIC, 0, 0, client_timeout_resend, client); if (r < 0) goto error; r = sd_event_source_set_priority(client->timeout_resend, client->event_priority); if (r < 0) goto error; } else if (r == -ENOMSG) /* invalid message, let's ignore it */ return 0; break; case DHCP_STATE_REBOOTING: case DHCP_STATE_REQUESTING: case DHCP_STATE_RENEWING: case DHCP_STATE_REBINDING: r = client_handle_ack(client, message, len); if (r == DHCP_EVENT_NO_LEASE) { client->timeout_resend = sd_event_source_unref(client->timeout_resend); if (client->state == DHCP_STATE_REBOOTING) { r = client_initialize(client); if (r < 0) goto error; r = client_start(client); if (r < 0) goto error; } goto error; } else if (r >= 0) { client->timeout_resend = sd_event_source_unref(client->timeout_resend); if (IN_SET(client->state, DHCP_STATE_REQUESTING, DHCP_STATE_REBOOTING)) notify_event = DHCP_EVENT_IP_ACQUIRE; else if (r != DHCP_EVENT_IP_ACQUIRE) notify_event = r; client->state = DHCP_STATE_BOUND; client->attempt = 1; client->last_addr = client->lease->address; r = client_set_lease_timeouts(client); if (r < 0) goto error; if (notify_event) { client = client_notify(client, notify_event); if (!client || client->state == DHCP_STATE_STOPPED) return 0; } client->receive_message = sd_event_source_unref(client->receive_message); client->fd = safe_close(client->fd); } else if (r == -ENOMSG) /* invalid message, let's ignore it */ return 0; break; case DHCP_STATE_INIT: case DHCP_STATE_INIT_REBOOT: case DHCP_STATE_BOUND: break; case DHCP_STATE_STOPPED: r = -EINVAL; goto error; } error: if (r < 0 || r == DHCP_EVENT_NO_LEASE) client_stop(client, r); return r; } static int client_receive_message_udp(sd_event_source *s, int fd, uint32_t revents, void *userdata) { sd_dhcp_client *client = userdata; _cleanup_free_ DHCPMessage *message = NULL; int buflen = 0, len, r; assert(s); assert(client); r = ioctl(fd, FIONREAD, &buflen); if (r < 0 || buflen <= 0) buflen = sizeof(DHCPMessage) + DHCP_MIN_OPTIONS_SIZE; message = malloc0(buflen); if (!message) return -ENOMEM; len = read(fd, message, buflen); if (len < 0) { log_dhcp_client(client, "could not receive message from UDP " "socket: %s", strerror(errno)); return 0; } else if ((size_t)len < sizeof(DHCPMessage)) return 0; return client_handle_message(client, message, len); } static int client_receive_message_raw(sd_event_source *s, int fd, uint32_t revents, void *userdata) { sd_dhcp_client *client = userdata; _cleanup_free_ DHCPPacket *packet = NULL; uint8_t cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))]; struct iovec iov = {}; struct msghdr msg = { .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsgbuf, .msg_controllen = sizeof(cmsgbuf), }; struct cmsghdr *cmsg; bool checksum = true; int buflen = 0, len, r; assert(s); assert(client); r = ioctl(fd, FIONREAD, &buflen); if (r < 0 || buflen <= 0) buflen = sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE; packet = malloc0(buflen); if (!packet) return -ENOMEM; iov.iov_base = packet; iov.iov_len = buflen; len = recvmsg(fd, &msg, 0); if (len < 0) { log_dhcp_client(client, "could not receive message from raw " "socket: %s", strerror(errno)); return 0; } else if ((size_t)len < sizeof(DHCPPacket)) return 0; for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) { if (cmsg->cmsg_level == SOL_PACKET && cmsg->cmsg_type == PACKET_AUXDATA && cmsg->cmsg_len == CMSG_LEN(sizeof(struct tpacket_auxdata))) { struct tpacket_auxdata *aux = (struct tpacket_auxdata*)CMSG_DATA(cmsg); checksum = !(aux->tp_status & TP_STATUS_CSUMNOTREADY); break; } } r = dhcp_packet_verify_headers(packet, len, checksum); if (r < 0) return 0; len -= DHCP_IP_UDP_SIZE; return client_handle_message(client, &packet->dhcp, len); } int sd_dhcp_client_start(sd_dhcp_client *client) { int r; assert_return(client, -EINVAL); r = client_initialize(client); if (r < 0) return r; if (client->last_addr) client->state = DHCP_STATE_INIT_REBOOT; return client_start(client); } int sd_dhcp_client_stop(sd_dhcp_client *client) { assert_return(client, -EINVAL); if (client_stop(client, DHCP_EVENT_STOP)) client->state = DHCP_STATE_STOPPED; return 0; } int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event, int priority) { int r; assert_return(client, -EINVAL); assert_return(!client->event, -EBUSY); if (event) client->event = sd_event_ref(event); else { r = sd_event_default(&client->event); if (r < 0) return 0; } client->event_priority = priority; return 0; } int sd_dhcp_client_detach_event(sd_dhcp_client *client) { assert_return(client, -EINVAL); client->event = sd_event_unref(client->event); return 0; } sd_event *sd_dhcp_client_get_event(sd_dhcp_client *client) { if (!client) return NULL; return client->event; } sd_dhcp_client *sd_dhcp_client_ref(sd_dhcp_client *client) { if (client) assert_se(REFCNT_INC(client->n_ref) >= 2); return client; } sd_dhcp_client *sd_dhcp_client_unref(sd_dhcp_client *client) { if (client && REFCNT_DEC(client->n_ref) <= 0) { log_dhcp_client(client, "UNREF"); client_initialize(client); client->receive_message = sd_event_source_unref(client->receive_message); sd_dhcp_client_detach_event(client); free(client->req_opts); free(client); return NULL; } return client; } DEFINE_TRIVIAL_CLEANUP_FUNC(sd_dhcp_client*, sd_dhcp_client_unref); #define _cleanup_dhcp_client_free_ _cleanup_(sd_dhcp_client_unrefp) int sd_dhcp_client_new(sd_dhcp_client **ret) { _cleanup_dhcp_client_free_ sd_dhcp_client *client = NULL; assert_return(ret, -EINVAL); client = new0(sd_dhcp_client, 1); if (!client) return -ENOMEM; client->n_ref = REFCNT_INIT; client->state = DHCP_STATE_INIT; client->index = -1; client->fd = -1; client->attempt = 1; client->req_opts_size = ELEMENTSOF(default_req_opts); client->req_opts = memdup(default_req_opts, client->req_opts_size); if (!client->req_opts) return -ENOMEM; *ret = client; client = NULL; return 0; }