| /* SPDX-License-Identifier: LGPL-2.1+ */ |
| /*** |
| Copyright © 2013 Intel Corporation. All rights reserved. |
| ***/ |
| |
| #include <errno.h> |
| #include <net/ethernet.h> |
| #include <net/if_arp.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/ioctl.h> |
| #include <linux/if_infiniband.h> |
| |
| #include "sd-dhcp-client.h" |
| |
| #include "alloc-util.h" |
| #include "async.h" |
| #include "dhcp-identifier.h" |
| #include "dhcp-internal.h" |
| #include "dhcp-lease-internal.h" |
| #include "dhcp-protocol.h" |
| #include "dns-domain.h" |
| #include "event-util.h" |
| #include "hostname-util.h" |
| #include "io-util.h" |
| #include "memory-util.h" |
| #include "random-util.h" |
| #include "string-util.h" |
| #include "strv.h" |
| |
| #define MAX_CLIENT_ID_LEN (sizeof(uint32_t) + MAX_DUID_LEN) /* Arbitrary limit */ |
| #define MAX_MAC_ADDR_LEN CONST_MAX(INFINIBAND_ALEN, ETH_ALEN) |
| |
| #define RESTART_AFTER_NAK_MIN_USEC (1 * USEC_PER_SEC) |
| #define RESTART_AFTER_NAK_MAX_USEC (30 * USEC_PER_MINUTE) |
| |
| struct sd_dhcp_client { |
| unsigned n_ref; |
| |
| DHCPState state; |
| sd_event *event; |
| int event_priority; |
| sd_event_source *timeout_resend; |
| int ifindex; |
| int fd; |
| uint16_t port; |
| union sockaddr_union link; |
| sd_event_source *receive_message; |
| bool request_broadcast; |
| uint8_t *req_opts; |
| size_t req_opts_allocated; |
| size_t req_opts_size; |
| bool anonymize; |
| be32_t last_addr; |
| uint8_t mac_addr[MAX_MAC_ADDR_LEN]; |
| size_t mac_addr_len; |
| uint16_t arp_type; |
| struct { |
| uint8_t type; |
| union { |
| struct { |
| /* 0: Generic (non-LL) (RFC 2132) */ |
| uint8_t data[MAX_CLIENT_ID_LEN]; |
| } _packed_ gen; |
| struct { |
| /* 1: Ethernet Link-Layer (RFC 2132) */ |
| uint8_t haddr[ETH_ALEN]; |
| } _packed_ eth; |
| struct { |
| /* 2 - 254: ARP/Link-Layer (RFC 2132) */ |
| uint8_t haddr[0]; |
| } _packed_ ll; |
| struct { |
| /* 255: Node-specific (RFC 4361) */ |
| be32_t iaid; |
| struct duid duid; |
| } _packed_ ns; |
| struct { |
| uint8_t data[MAX_CLIENT_ID_LEN]; |
| } _packed_ raw; |
| }; |
| } _packed_ client_id; |
| size_t client_id_len; |
| char *hostname; |
| char *vendor_class_identifier; |
| char **user_class; |
| uint32_t mtu; |
| uint32_t xid; |
| usec_t start_time; |
| unsigned attempt; |
| usec_t request_sent; |
| sd_event_source *timeout_t1; |
| sd_event_source *timeout_t2; |
| sd_event_source *timeout_expire; |
| sd_dhcp_client_callback_t callback; |
| void *userdata; |
| sd_dhcp_lease *lease; |
| usec_t start_delay; |
| }; |
| |
| static const uint8_t default_req_opts[] = { |
| SD_DHCP_OPTION_SUBNET_MASK, |
| SD_DHCP_OPTION_ROUTER, |
| SD_DHCP_OPTION_HOST_NAME, |
| SD_DHCP_OPTION_DOMAIN_NAME, |
| SD_DHCP_OPTION_DOMAIN_NAME_SERVER, |
| }; |
| |
| /* RFC7844 section 3: |
| MAY contain the Parameter Request List option. |
| RFC7844 section 3.6: |
| The client intending to protect its privacy SHOULD only request a |
| minimal number of options in the PRL and SHOULD also randomly shuffle |
| the ordering of option codes in the PRL. If this random ordering |
| cannot be implemented, the client MAY order the option codes in the |
| PRL by option code number (lowest to highest). |
| */ |
| /* NOTE: using PRL options that Windows 10 RFC7844 implementation uses */ |
| static const uint8_t default_req_opts_anonymize[] = { |
| SD_DHCP_OPTION_SUBNET_MASK, /* 1 */ |
| SD_DHCP_OPTION_ROUTER, /* 3 */ |
| SD_DHCP_OPTION_DOMAIN_NAME_SERVER, /* 6 */ |
| SD_DHCP_OPTION_DOMAIN_NAME, /* 15 */ |
| SD_DHCP_OPTION_ROUTER_DISCOVER, /* 31 */ |
| SD_DHCP_OPTION_STATIC_ROUTE, /* 33 */ |
| SD_DHCP_OPTION_VENDOR_SPECIFIC, /* 43 */ |
| SD_DHCP_OPTION_NETBIOS_NAMESERVER, /* 44 */ |
| SD_DHCP_OPTION_NETBIOS_NODETYPE, /* 46 */ |
| SD_DHCP_OPTION_NETBIOS_SCOPE, /* 47 */ |
| SD_DHCP_OPTION_CLASSLESS_STATIC_ROUTE, /* 121 */ |
| SD_DHCP_OPTION_PRIVATE_CLASSLESS_STATIC_ROUTE, /* 249 */ |
| SD_DHCP_OPTION_PRIVATE_PROXY_AUTODISCOVERY, /* 252 */ |
| }; |
| |
| 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 void client_stop(sd_dhcp_client *client, int error); |
| |
| int sd_dhcp_client_set_callback( |
| sd_dhcp_client *client, |
| sd_dhcp_client_callback_t cb, |
| void *userdata) { |
| |
| assert_return(client, -EINVAL); |
| |
| client->callback = cb; |
| client->userdata = userdata; |
| |
| return 0; |
| } |
| |
| int sd_dhcp_client_set_request_broadcast(sd_dhcp_client *client, int broadcast) { |
| assert_return(client, -EINVAL); |
| |
| client->request_broadcast = !!broadcast; |
| |
| 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 SD_DHCP_OPTION_PAD: |
| case SD_DHCP_OPTION_OVERLOAD: |
| case SD_DHCP_OPTION_MESSAGE_TYPE: |
| case SD_DHCP_OPTION_PARAMETER_REQUEST_LIST: |
| case SD_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_ifindex(sd_dhcp_client *client, int ifindex) { |
| |
| assert_return(client, -EINVAL); |
| assert_return(IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_STOPPED), -EBUSY); |
| assert_return(ifindex > 0, -EINVAL); |
| |
| client->ifindex = ifindex; |
| return 0; |
| } |
| |
| int sd_dhcp_client_set_mac( |
| sd_dhcp_client *client, |
| const uint8_t *addr, |
| size_t addr_len, |
| uint16_t arp_type) { |
| |
| DHCP_CLIENT_DONT_DESTROY(client); |
| bool need_restart = false; |
| |
| assert_return(client, -EINVAL); |
| assert_return(addr, -EINVAL); |
| assert_return(addr_len > 0 && addr_len <= MAX_MAC_ADDR_LEN, -EINVAL); |
| assert_return(arp_type > 0, -EINVAL); |
| |
| if (arp_type == ARPHRD_ETHER) |
| assert_return(addr_len == ETH_ALEN, -EINVAL); |
| else if (arp_type == ARPHRD_INFINIBAND) |
| assert_return(addr_len == INFINIBAND_ALEN, -EINVAL); |
| else |
| return -EINVAL; |
| |
| if (client->mac_addr_len == addr_len && |
| memcmp(&client->mac_addr, addr, addr_len) == 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_stop(client, SD_DHCP_CLIENT_EVENT_STOP); |
| } |
| |
| memcpy(&client->mac_addr, addr, addr_len); |
| client->mac_addr_len = addr_len; |
| client->arp_type = arp_type; |
| |
| if (need_restart && client->state != DHCP_STATE_STOPPED) |
| sd_dhcp_client_start(client); |
| |
| return 0; |
| } |
| |
| int sd_dhcp_client_get_client_id( |
| sd_dhcp_client *client, |
| uint8_t *type, |
| const uint8_t **data, |
| size_t *data_len) { |
| |
| assert_return(client, -EINVAL); |
| assert_return(type, -EINVAL); |
| assert_return(data, -EINVAL); |
| assert_return(data_len, -EINVAL); |
| |
| *type = 0; |
| *data = NULL; |
| *data_len = 0; |
| if (client->client_id_len) { |
| *type = client->client_id.type; |
| *data = client->client_id.raw.data; |
| *data_len = client->client_id_len - sizeof(client->client_id.type); |
| } |
| |
| return 0; |
| } |
| |
| int sd_dhcp_client_set_client_id( |
| sd_dhcp_client *client, |
| uint8_t type, |
| const uint8_t *data, |
| size_t data_len) { |
| |
| DHCP_CLIENT_DONT_DESTROY(client); |
| bool need_restart = false; |
| |
| assert_return(client, -EINVAL); |
| assert_return(data, -EINVAL); |
| assert_return(data_len > 0 && data_len <= MAX_CLIENT_ID_LEN, -EINVAL); |
| |
| if (client->client_id_len == data_len + sizeof(client->client_id.type) && |
| client->client_id.type == type && |
| memcmp(&client->client_id.raw.data, data, data_len) == 0) |
| return 0; |
| |
| /* For hardware types, log debug message about unexpected data length. |
| * |
| * Note that infiniband's INFINIBAND_ALEN is 20 bytes long, but only |
| * last last 8 bytes of the address are stable and suitable to put into |
| * the client-id. The caller is advised to account for that. */ |
| if ((type == ARPHRD_ETHER && data_len != ETH_ALEN) || |
| (type == ARPHRD_INFINIBAND && data_len != 8)) |
| log_dhcp_client(client, "Changing client ID to hardware type %u with " |
| "unexpected address length %zu", |
| type, data_len); |
| |
| if (!IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_STOPPED)) { |
| log_dhcp_client(client, "Changing client ID on running DHCP " |
| "client, restarting"); |
| need_restart = true; |
| client_stop(client, SD_DHCP_CLIENT_EVENT_STOP); |
| } |
| |
| client->client_id.type = type; |
| memcpy(&client->client_id.raw.data, data, data_len); |
| client->client_id_len = data_len + sizeof (client->client_id.type); |
| |
| if (need_restart && client->state != DHCP_STATE_STOPPED) |
| sd_dhcp_client_start(client); |
| |
| return 0; |
| } |
| |
| /** |
| * Sets IAID and DUID. If duid is non-null, the DUID is set to duid_type + duid |
| * without further modification. Otherwise, if duid_type is supported, DUID |
| * is set based on that type. Otherwise, an error is returned. |
| */ |
| static int dhcp_client_set_iaid_duid_internal( |
| sd_dhcp_client *client, |
| bool iaid_append, |
| bool iaid_set, |
| uint32_t iaid, |
| uint16_t duid_type, |
| const void *duid, |
| size_t duid_len, |
| usec_t llt_time) { |
| |
| DHCP_CLIENT_DONT_DESTROY(client); |
| int r; |
| size_t len; |
| |
| assert_return(client, -EINVAL); |
| assert_return(duid_len == 0 || duid, -EINVAL); |
| |
| if (duid) { |
| r = dhcp_validate_duid_len(duid_type, duid_len, true); |
| if (r < 0) |
| return r; |
| } |
| |
| zero(client->client_id); |
| client->client_id.type = 255; |
| |
| if (iaid_append) { |
| if (iaid_set) |
| client->client_id.ns.iaid = htobe32(iaid); |
| else { |
| r = dhcp_identifier_set_iaid(client->ifindex, client->mac_addr, |
| client->mac_addr_len, |
| true, |
| &client->client_id.ns.iaid); |
| if (r < 0) |
| return r; |
| } |
| } |
| |
| if (duid) { |
| client->client_id.ns.duid.type = htobe16(duid_type); |
| memcpy(&client->client_id.ns.duid.raw.data, duid, duid_len); |
| len = sizeof(client->client_id.ns.duid.type) + duid_len; |
| } else |
| switch (duid_type) { |
| case DUID_TYPE_LLT: |
| if (client->mac_addr_len == 0) |
| return -EOPNOTSUPP; |
| |
| r = dhcp_identifier_set_duid_llt(&client->client_id.ns.duid, llt_time, client->mac_addr, client->mac_addr_len, client->arp_type, &len); |
| if (r < 0) |
| return r; |
| break; |
| case DUID_TYPE_EN: |
| r = dhcp_identifier_set_duid_en(&client->client_id.ns.duid, &len); |
| if (r < 0) |
| return r; |
| break; |
| case DUID_TYPE_LL: |
| if (client->mac_addr_len == 0) |
| return -EOPNOTSUPP; |
| |
| r = dhcp_identifier_set_duid_ll(&client->client_id.ns.duid, client->mac_addr, client->mac_addr_len, client->arp_type, &len); |
| if (r < 0) |
| return r; |
| break; |
| case DUID_TYPE_UUID: |
| r = dhcp_identifier_set_duid_uuid(&client->client_id.ns.duid, &len); |
| if (r < 0) |
| return r; |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| client->client_id_len = sizeof(client->client_id.type) + len + |
| (iaid_append ? sizeof(client->client_id.ns.iaid) : 0); |
| |
| if (!IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_STOPPED)) { |
| log_dhcp_client(client, "Configured %sDUID, restarting.", iaid_append ? "IAID+" : ""); |
| client_stop(client, SD_DHCP_CLIENT_EVENT_STOP); |
| sd_dhcp_client_start(client); |
| } |
| |
| return 0; |
| } |
| |
| int sd_dhcp_client_set_iaid_duid( |
| sd_dhcp_client *client, |
| bool iaid_set, |
| uint32_t iaid, |
| uint16_t duid_type, |
| const void *duid, |
| size_t duid_len) { |
| return dhcp_client_set_iaid_duid_internal(client, true, iaid_set, iaid, duid_type, duid, duid_len, 0); |
| } |
| |
| int sd_dhcp_client_set_iaid_duid_llt( |
| sd_dhcp_client *client, |
| bool iaid_set, |
| uint32_t iaid, |
| usec_t llt_time) { |
| return dhcp_client_set_iaid_duid_internal(client, true, iaid_set, iaid, DUID_TYPE_LLT, NULL, 0, llt_time); |
| } |
| |
| int sd_dhcp_client_set_duid( |
| sd_dhcp_client *client, |
| uint16_t duid_type, |
| const void *duid, |
| size_t duid_len) { |
| return dhcp_client_set_iaid_duid_internal(client, false, false, 0, duid_type, duid, duid_len, 0); |
| } |
| |
| int sd_dhcp_client_set_duid_llt( |
| sd_dhcp_client *client, |
| usec_t llt_time) { |
| return dhcp_client_set_iaid_duid_internal(client, false, false, 0, DUID_TYPE_LLT, NULL, 0, llt_time); |
| } |
| |
| int sd_dhcp_client_set_hostname( |
| sd_dhcp_client *client, |
| const char *hostname) { |
| |
| assert_return(client, -EINVAL); |
| |
| /* Make sure hostnames qualify as DNS and as Linux hostnames */ |
| if (hostname && |
| !(hostname_is_valid(hostname, false) && dns_name_is_valid(hostname) > 0)) |
| return -EINVAL; |
| |
| return free_and_strdup(&client->hostname, hostname); |
| } |
| |
| int sd_dhcp_client_set_vendor_class_identifier( |
| sd_dhcp_client *client, |
| const char *vci) { |
| |
| assert_return(client, -EINVAL); |
| |
| return free_and_strdup(&client->vendor_class_identifier, vci); |
| } |
| |
| int sd_dhcp_client_set_user_class( |
| sd_dhcp_client *client, |
| const char* const* user_class) { |
| |
| _cleanup_strv_free_ char **s = NULL; |
| char **p; |
| |
| STRV_FOREACH(p, (char **) user_class) |
| if (strlen(*p) > 255) |
| return -ENAMETOOLONG; |
| |
| s = strv_copy((char **) user_class); |
| if (!s) |
| return -ENOMEM; |
| |
| client->user_class = TAKE_PTR(s); |
| |
| return 0; |
| } |
| |
| int sd_dhcp_client_set_client_port( |
| sd_dhcp_client *client, |
| uint16_t port) { |
| |
| assert_return(client, -EINVAL); |
| |
| client->port = port; |
| |
| return 0; |
| } |
| |
| int sd_dhcp_client_set_mtu(sd_dhcp_client *client, uint32_t mtu) { |
| assert_return(client, -EINVAL); |
| assert_return(mtu >= DHCP_DEFAULT_MIN_SIZE, -ERANGE); |
| |
| client->mtu = mtu; |
| |
| return 0; |
| } |
| |
| int sd_dhcp_client_get_lease(sd_dhcp_client *client, sd_dhcp_lease **ret) { |
| assert_return(client, -EINVAL); |
| |
| if (!IN_SET(client->state, DHCP_STATE_BOUND, DHCP_STATE_RENEWING, DHCP_STATE_REBINDING)) |
| return -EADDRNOTAVAIL; |
| |
| if (ret) |
| *ret = client->lease; |
| |
| return 0; |
| } |
| |
| static void client_notify(sd_dhcp_client *client, int event) { |
| assert(client); |
| |
| if (client->callback) |
| client->callback(client, event, client->userdata); |
| } |
| |
| static int client_initialize(sd_dhcp_client *client) { |
| assert_return(client, -EINVAL); |
| |
| client->receive_message = sd_event_source_unref(client->receive_message); |
| |
| client->fd = asynchronous_close(client->fd); |
| |
| (void) event_source_disable(client->timeout_resend); |
| (void) event_source_disable(client->timeout_t1); |
| (void) event_source_disable(client->timeout_t2); |
| (void) event_source_disable(client->timeout_expire); |
| |
| client->attempt = 1; |
| |
| client->state = DHCP_STATE_INIT; |
| client->xid = 0; |
| |
| client->lease = sd_dhcp_lease_unref(client->lease); |
| |
| return 0; |
| } |
| |
| static void client_stop(sd_dhcp_client *client, int error) { |
| assert(client); |
| |
| if (error < 0) |
| log_dhcp_client(client, "STOPPED: %s", strerror(-error)); |
| else if (error == SD_DHCP_CLIENT_EVENT_STOP) |
| log_dhcp_client(client, "STOPPED"); |
| else |
| log_dhcp_client(client, "STOPPED: Unknown event"); |
| |
| client_notify(client, error); |
| |
| client_initialize(client); |
| } |
| |
| static int client_message_init( |
| sd_dhcp_client *client, |
| DHCPPacket **ret, |
| uint8_t type, |
| size_t *_optlen, |
| size_t *_optoffset) { |
| |
| _cleanup_free_ DHCPPacket *packet = NULL; |
| size_t optlen, optoffset, size; |
| be16_t max_size; |
| usec_t time_now; |
| uint16_t secs; |
| int r; |
| |
| assert(client); |
| assert(client->start_time); |
| assert(ret); |
| assert(_optlen); |
| assert(_optoffset); |
| assert(IN_SET(type, DHCP_DISCOVER, DHCP_REQUEST)); |
| |
| optlen = DHCP_MIN_OPTIONS_SIZE; |
| size = sizeof(DHCPPacket) + optlen; |
| |
| packet = malloc0(size); |
| if (!packet) |
| return -ENOMEM; |
| |
| r = dhcp_message_init(&packet->dhcp, BOOTREQUEST, client->xid, type, |
| client->arp_type, optlen, &optoffset); |
| 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 */ |
| r = sd_event_now(client->event, clock_boottime_or_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 */ |
| secs = ((time_now - client->start_time) / USEC_PER_SEC) ? : 1; |
| packet->dhcp.secs = htobe16(secs); |
| |
| /* RFC2132 section 4.1 |
| A client that cannot receive unicast IP datagrams until its protocol |
| software has been configured with an IP address SHOULD set the |
| BROADCAST bit in the 'flags' field to 1 in any DHCPDISCOVER or |
| DHCPREQUEST messages that client sends. The BROADCAST bit will |
| provide a hint to the DHCP server and BOOTP relay agent to broadcast |
| any messages to the client on the client's subnet. |
| |
| Note: some interfaces needs this to be enabled, but some networks |
| needs this to be disabled as broadcasts are filteretd, so this |
| needs to be configurable */ |
| if (client->request_broadcast || client->arp_type != ARPHRD_ETHER) |
| packet->dhcp.flags = htobe16(0x8000); |
| |
| /* RFC2132 section 4.1.1: |
| The client MUST include its hardware address in the ’chaddr’ field, if |
| necessary for delivery of DHCP reply messages. Non-Ethernet |
| interfaces will leave 'chaddr' empty and use the client identifier |
| instead (eg, RFC 4390 section 2.1). |
| */ |
| if (client->arp_type == ARPHRD_ETHER) |
| memcpy(&packet->dhcp.chaddr, &client->mac_addr, ETH_ALEN); |
| |
| /* If no client identifier exists, construct an RFC 4361-compliant one */ |
| if (client->client_id_len == 0) { |
| size_t duid_len; |
| |
| client->client_id.type = 255; |
| |
| r = dhcp_identifier_set_iaid(client->ifindex, client->mac_addr, client->mac_addr_len, |
| true, &client->client_id.ns.iaid); |
| if (r < 0) |
| return r; |
| |
| r = dhcp_identifier_set_duid_en(&client->client_id.ns.duid, &duid_len); |
| if (r < 0) |
| return r; |
| |
| client->client_id_len = sizeof(client->client_id.type) + sizeof(client->client_id.ns.iaid) + duid_len; |
| } |
| |
| /* Some DHCP servers will refuse to issue an DHCP lease if the Client |
| Identifier option is not set */ |
| if (client->client_id_len) { |
| r = dhcp_option_append(&packet->dhcp, optlen, &optoffset, 0, |
| SD_DHCP_OPTION_CLIENT_IDENTIFIER, |
| client->client_id_len, |
| &client->client_id); |
| if (r < 0) |
| return r; |
| } |
| |
| /* RFC2131 section 3.5: |
| in its initial DHCPDISCOVER or DHCPREQUEST message, a |
| client may provide the server with a list of specific |
| parameters the client is interested in. If the client |
| includes a list of parameters in a DHCPDISCOVER message, |
| it MUST include that list in any subsequent DHCPREQUEST |
| messages. |
| */ |
| |
| /* RFC7844 section 3: |
| MAY contain the Parameter Request List option. */ |
| /* NOTE: in case that there would be an option to do not send |
| * any PRL at all, the size should be checked before sending */ |
| if (client->req_opts_size > 0) { |
| r = dhcp_option_append(&packet->dhcp, optlen, &optoffset, 0, |
| SD_DHCP_OPTION_PARAMETER_REQUEST_LIST, |
| client->req_opts_size, client->req_opts); |
| if (r < 0) |
| return r; |
| } |
| |
| /* RFC2131 section 3.5: |
| The client SHOULD include the ’maximum DHCP message size’ option to |
| let the server know how large the server may make its DHCP messages. |
| |
| Note (from ConnMan): Some DHCP servers will send bigger DHCP packets |
| than the defined default size unless the Maximum Message Size option |
| is explicitly set |
| |
| RFC3442 "Requirements to Avoid Sizing Constraints": |
| Because a full routing table can be quite large, the standard 576 |
| octet maximum size for a DHCP message may be too short to contain |
| some legitimate Classless Static Route options. Because of this, |
| clients implementing the Classless Static Route option SHOULD send a |
| Maximum DHCP Message Size [4] option if the DHCP client's TCP/IP |
| stack is capable of receiving larger IP datagrams. In this case, the |
| client SHOULD set the value of this option to at least the MTU of the |
| interface that the client is configuring. The client MAY set the |
| value of this option higher, up to the size of the largest UDP packet |
| it is prepared to accept. (Note that the value specified in the |
| Maximum DHCP Message Size option is the total maximum packet size, |
| including IP and UDP headers.) |
| */ |
| /* RFC7844 section 3: |
| SHOULD NOT contain any other option. */ |
| if (!client->anonymize) { |
| max_size = htobe16(size); |
| r = dhcp_option_append(&packet->dhcp, client->mtu, &optoffset, 0, |
| SD_DHCP_OPTION_MAXIMUM_MESSAGE_SIZE, |
| 2, &max_size); |
| if (r < 0) |
| return r; |
| } |
| |
| *_optlen = optlen; |
| *_optoffset = optoffset; |
| *ret = TAKE_PTR(packet); |
| |
| return 0; |
| } |
| |
| static int client_append_fqdn_option( |
| DHCPMessage *message, |
| size_t optlen, |
| size_t *optoffset, |
| const char *fqdn) { |
| |
| uint8_t buffer[3 + DHCP_MAX_FQDN_LENGTH]; |
| int r; |
| |
| buffer[0] = DHCP_FQDN_FLAG_S | /* Request server to perform A RR DNS updates */ |
| DHCP_FQDN_FLAG_E; /* Canonical wire format */ |
| buffer[1] = 0; /* RCODE1 (deprecated) */ |
| buffer[2] = 0; /* RCODE2 (deprecated) */ |
| |
| r = dns_name_to_wire_format(fqdn, buffer + 3, sizeof(buffer) - 3, false); |
| if (r > 0) |
| r = dhcp_option_append(message, optlen, optoffset, 0, |
| SD_DHCP_OPTION_FQDN, 3 + r, buffer); |
| |
| return r; |
| } |
| |
| static int dhcp_client_send_raw( |
| sd_dhcp_client *client, |
| DHCPPacket *packet, |
| size_t len) { |
| |
| dhcp_packet_append_ip_headers(packet, INADDR_ANY, client->port, |
| 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 optoffset, optlen; |
| int r; |
| |
| assert(client); |
| assert(IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_SELECTING)); |
| |
| r = client_message_init(client, &discover, DHCP_DISCOVER, |
| &optlen, &optoffset); |
| if (r < 0) |
| return r; |
| |
| /* the client may suggest values for the network address |
| and lease time in the DHCPDISCOVER message. The client may include |
| the ’requested IP address’ option to suggest that a particular IP |
| address be assigned, and may include the ’IP address lease time’ |
| option to suggest the lease time it would like. |
| */ |
| if (client->last_addr != INADDR_ANY) { |
| r = dhcp_option_append(&discover->dhcp, optlen, &optoffset, 0, |
| SD_DHCP_OPTION_REQUESTED_IP_ADDRESS, |
| 4, &client->last_addr); |
| if (r < 0) |
| return r; |
| } |
| |
| if (client->hostname) { |
| /* According to RFC 4702 "clients that send the Client FQDN option in |
| their messages MUST NOT also send the Host Name option". Just send |
| one of the two depending on the hostname type. |
| */ |
| if (dns_name_is_single_label(client->hostname)) { |
| /* it is unclear from RFC 2131 if client should send hostname in |
| DHCPDISCOVER but dhclient does and so we do as well |
| */ |
| r = dhcp_option_append(&discover->dhcp, optlen, &optoffset, 0, |
| SD_DHCP_OPTION_HOST_NAME, |
| strlen(client->hostname), client->hostname); |
| } else |
| r = client_append_fqdn_option(&discover->dhcp, optlen, &optoffset, |
| client->hostname); |
| if (r < 0) |
| return r; |
| } |
| |
| if (client->vendor_class_identifier) { |
| r = dhcp_option_append(&discover->dhcp, optlen, &optoffset, 0, |
| SD_DHCP_OPTION_VENDOR_CLASS_IDENTIFIER, |
| strlen(client->vendor_class_identifier), |
| client->vendor_class_identifier); |
| if (r < 0) |
| return r; |
| } |
| |
| if (client->user_class) { |
| r = dhcp_option_append(&discover->dhcp, optlen, &optoffset, 0, |
| SD_DHCP_OPTION_USER_CLASS, |
| strv_length(client->user_class), |
| client->user_class); |
| if (r < 0) |
| return r; |
| } |
| |
| r = dhcp_option_append(&discover->dhcp, optlen, &optoffset, 0, |
| SD_DHCP_OPTION_END, 0, NULL); |
| if (r < 0) |
| return r; |
| |
| /* We currently ignore: |
| The client SHOULD wait a random time between one and ten seconds to |
| desynchronize the use of DHCP at startup. |
| */ |
| r = dhcp_client_send_raw(client, discover, sizeof(DHCPPacket) + optoffset); |
| 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 = NULL; |
| size_t optoffset, optlen; |
| int r; |
| |
| assert(client); |
| |
| r = client_message_init(client, &request, DHCP_REQUEST, &optlen, &optoffset); |
| if (r < 0) |
| return r; |
| |
| switch (client->state) { |
| /* See RFC2131 section 4.3.2 (note that there is a typo in the RFC, |
| SELECTING should be REQUESTING) |
| */ |
| |
| case DHCP_STATE_REQUESTING: |
| /* Client inserts the address of the selected server in ’server |
| identifier’, ’ciaddr’ MUST be zero, ’requested IP address’ MUST be |
| filled in with the yiaddr value from the chosen DHCPOFFER. |
| */ |
| |
| r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0, |
| SD_DHCP_OPTION_SERVER_IDENTIFIER, |
| 4, &client->lease->server_address); |
| if (r < 0) |
| return r; |
| |
| r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0, |
| SD_DHCP_OPTION_REQUESTED_IP_ADDRESS, |
| 4, &client->lease->address); |
| if (r < 0) |
| return r; |
| |
| break; |
| |
| case DHCP_STATE_INIT_REBOOT: |
| /* ’server identifier’ MUST NOT be filled in, ’requested IP address’ |
| option MUST be filled in with client’s notion of its previously |
| assigned address. ’ciaddr’ MUST be zero. |
| */ |
| r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0, |
| SD_DHCP_OPTION_REQUESTED_IP_ADDRESS, |
| 4, &client->last_addr); |
| if (r < 0) |
| return r; |
| break; |
| |
| case DHCP_STATE_RENEWING: |
| /* ’server identifier’ MUST NOT be filled in, ’requested IP address’ |
| option MUST NOT be filled in, ’ciaddr’ MUST be filled in with |
| client’s IP address. |
| */ |
| |
| case DHCP_STATE_REBINDING: |
| /* ’server identifier’ MUST NOT be filled in, ’requested IP address’ |
| option MUST NOT be filled in, ’ciaddr’ MUST be filled in with |
| client’s IP address. |
| |
| This message MUST be broadcast to the 0xffffffff IP broadcast address. |
| */ |
| request->dhcp.ciaddr = client->lease->address; |
| |
| break; |
| |
| case DHCP_STATE_INIT: |
| case DHCP_STATE_SELECTING: |
| case DHCP_STATE_REBOOTING: |
| case DHCP_STATE_BOUND: |
| case DHCP_STATE_STOPPED: |
| return -EINVAL; |
| } |
| |
| if (client->hostname) { |
| if (dns_name_is_single_label(client->hostname)) |
| r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0, |
| SD_DHCP_OPTION_HOST_NAME, |
| strlen(client->hostname), client->hostname); |
| else |
| r = client_append_fqdn_option(&request->dhcp, optlen, &optoffset, |
| client->hostname); |
| if (r < 0) |
| return r; |
| } |
| |
| if (client->vendor_class_identifier) { |
| r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0, |
| SD_DHCP_OPTION_VENDOR_CLASS_IDENTIFIER, |
| strlen(client->vendor_class_identifier), |
| client->vendor_class_identifier); |
| if (r < 0) |
| return r; |
| } |
| |
| r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0, |
| SD_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, |
| sizeof(DHCPMessage) + optoffset); |
| } else { |
| r = dhcp_client_send_raw(client, request, sizeof(DHCPPacket) + optoffset); |
| } |
| if (r < 0) |
| return r; |
| |
| switch (client->state) { |
| |
| case DHCP_STATE_REQUESTING: |
| log_dhcp_client(client, "REQUEST (requesting)"); |
| break; |
| |
| case DHCP_STATE_INIT_REBOOT: |
| log_dhcp_client(client, "REQUEST (init-reboot)"); |
| break; |
| |
| case DHCP_STATE_RENEWING: |
| log_dhcp_client(client, "REQUEST (renewing)"); |
| break; |
| |
| case DHCP_STATE_REBINDING: |
| log_dhcp_client(client, "REQUEST (rebinding)"); |
| break; |
| |
| default: |
| log_dhcp_client(client, "REQUEST (invalid)"); |
| break; |
| } |
| |
| return 0; |
| } |
| |
| static int client_start(sd_dhcp_client *client); |
| |
| static int client_timeout_resend( |
| sd_event_source *s, |
| uint64_t usec, |
| void *userdata) { |
| |
| sd_dhcp_client *client = userdata; |
| DHCP_CLIENT_DONT_DESTROY(client); |
| 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_boottime_or_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 */ |
| r = client_initialize(client); |
| if (r < 0) |
| goto error; |
| |
| r = client_start(client); |
| if (r < 0) |
| goto error; |
| else { |
| log_dhcp_client(client, "REBOOTED"); |
| return 0; |
| } |
| |
| 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); |
| |
| r = event_reset_time(client->event, &client->timeout_resend, |
| clock_boottime_or_monotonic(), |
| next_timeout, 10 * USEC_PER_MSEC, |
| client_timeout_resend, client, |
| client->event_priority, "dhcp4-resend-timer", true); |
| 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_io_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; |
| |
| r = sd_event_source_set_description(client->receive_message, "dhcp4-receive-message"); |
| if (r < 0) |
| goto error; |
| |
| error: |
| if (r < 0) |
| client_stop(client, r); |
| |
| return 0; |
| } |
| |
| static int client_initialize_time_events(sd_dhcp_client *client) { |
| uint64_t usec = 0; |
| int r; |
| |
| assert(client); |
| assert(client->event); |
| |
| if (client->start_delay) { |
| assert_se(sd_event_now(client->event, clock_boottime_or_monotonic(), &usec) >= 0); |
| usec += client->start_delay; |
| } |
| |
| r = event_reset_time(client->event, &client->timeout_resend, |
| clock_boottime_or_monotonic(), |
| usec, 0, |
| client_timeout_resend, client, |
| client->event_priority, "dhcp4-resend-timer", true); |
| if (r < 0) |
| client_stop(client, r); |
| |
| return 0; |
| |
| } |
| |
| static int client_initialize_events(sd_dhcp_client *client, sd_event_io_handler_t io_callback) { |
| client_initialize_io_events(client, io_callback); |
| client_initialize_time_events(client); |
| |
| return 0; |
| } |
| |
| static int client_start_delayed(sd_dhcp_client *client) { |
| int r; |
| |
| assert_return(client, -EINVAL); |
| assert_return(client->event, -EINVAL); |
| assert_return(client->ifindex > 0, -EINVAL); |
| assert_return(client->fd < 0, -EBUSY); |
| assert_return(client->xid == 0, -EINVAL); |
| assert_return(IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_INIT_REBOOT), -EBUSY); |
| |
| client->xid = random_u32(); |
| |
| r = dhcp_network_bind_raw_socket(client->ifindex, &client->link, |
| client->xid, client->mac_addr, |
| client->mac_addr_len, client->arp_type, client->port); |
| if (r < 0) { |
| client_stop(client, r); |
| return r; |
| } |
| client->fd = r; |
| |
| if (IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_INIT_REBOOT)) |
| client->start_time = now(clock_boottime_or_monotonic()); |
| |
| return client_initialize_events(client, client_receive_message_raw); |
| } |
| |
| static int client_start(sd_dhcp_client *client) { |
| client->start_delay = 0; |
| return client_start_delayed(client); |
| } |
| |
| static int client_timeout_expire(sd_event_source *s, uint64_t usec, void *userdata) { |
| sd_dhcp_client *client = userdata; |
| DHCP_CLIENT_DONT_DESTROY(client); |
| |
| log_dhcp_client(client, "EXPIRED"); |
| |
| client_notify(client, SD_DHCP_CLIENT_EVENT_EXPIRED); |
| |
| /* lease was lost, start over if not freed or stopped in callback */ |
| if (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; |
| DHCP_CLIENT_DONT_DESTROY(client); |
| int r; |
| |
| assert(client); |
| |
| client->receive_message = sd_event_source_unref(client->receive_message); |
| client->fd = asynchronous_close(client->fd); |
| |
| client->state = DHCP_STATE_REBINDING; |
| client->attempt = 1; |
| |
| r = dhcp_network_bind_raw_socket(client->ifindex, &client->link, |
| client->xid, client->mac_addr, |
| client->mac_addr_len, client->arp_type, |
| client->port); |
| if (r < 0) { |
| client_stop(client, r); |
| return 0; |
| } |
| client->fd = r; |
| |
| 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; |
| DHCP_CLIENT_DONT_DESTROY(client); |
| |
| client->state = DHCP_STATE_RENEWING; |
| client->attempt = 1; |
| |
| return client_initialize_time_events(client); |
| } |
| |
| static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer, size_t len) { |
| _cleanup_(sd_dhcp_lease_unrefp) sd_dhcp_lease *lease = NULL; |
| int r; |
| |
| r = dhcp_lease_new(&lease); |
| if (r < 0) |
| return r; |
| |
| if (client->client_id_len) { |
| r = dhcp_lease_set_client_id(lease, |
| (uint8_t *) &client->client_id, |
| client->client_id_len); |
| if (r < 0) |
| return r; |
| } |
| |
| r = dhcp_option_parse(offer, len, dhcp_lease_parse_options, lease, NULL); |
| if (r != DHCP_OFFER) { |
| log_dhcp_client(client, "received message was not an OFFER, ignoring"); |
| return -ENOMSG; |
| } |
| |
| lease->next_server = offer->siaddr; |
| lease->address = offer->yiaddr; |
| |
| if (lease->address == 0 || |
| lease->server_address == 0 || |
| lease->lifetime == 0) { |
| log_dhcp_client(client, "received lease lacks address, server address or lease lifetime, ignoring"); |
| return -ENOMSG; |
| } |
| |
| if (!lease->have_subnet_mask) { |
| r = dhcp_lease_set_default_subnet_mask(lease); |
| if (r < 0) { |
| log_dhcp_client(client, |
| "received lease lacks subnet mask, " |
| "and a fallback one cannot be generated, ignoring"); |
| return -ENOMSG; |
| } |
| } |
| |
| sd_dhcp_lease_unref(client->lease); |
| client->lease = TAKE_PTR(lease); |
| |
| log_dhcp_client(client, "OFFER"); |
| |
| return 0; |
| } |
| |
| static int client_handle_forcerenew(sd_dhcp_client *client, DHCPMessage *force, size_t len) { |
| int r; |
| |
| r = dhcp_option_parse(force, len, NULL, NULL, NULL); |
| if (r != DHCP_FORCERENEW) |
| return -ENOMSG; |
| |
| log_dhcp_client(client, "FORCERENEW"); |
| |
| return 0; |
| } |
| |
| static int client_handle_ack(sd_dhcp_client *client, DHCPMessage *ack, size_t len) { |
| _cleanup_(sd_dhcp_lease_unrefp) sd_dhcp_lease *lease = NULL; |
| _cleanup_free_ char *error_message = NULL; |
| int r; |
| |
| r = dhcp_lease_new(&lease); |
| if (r < 0) |
| return r; |
| |
| if (client->client_id_len) { |
| r = dhcp_lease_set_client_id(lease, |
| (uint8_t *) &client->client_id, |
| client->client_id_len); |
| if (r < 0) |
| return r; |
| } |
| |
| r = dhcp_option_parse(ack, len, dhcp_lease_parse_options, lease, &error_message); |
| if (r == DHCP_NAK) { |
| log_dhcp_client(client, "NAK: %s", strna(error_message)); |
| return -EADDRNOTAVAIL; |
| } |
| |
| if (r != DHCP_ACK) { |
| log_dhcp_client(client, "received 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, "received 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, |
| "received lease lacks subnet mask, " |
| "and a fallback one cannot be generated, ignoring"); |
| return -ENOMSG; |
| } |
| } |
| |
| r = SD_DHCP_CLIENT_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 = SD_DHCP_CLIENT_EVENT_IP_CHANGE; |
| } else |
| r = SD_DHCP_CLIENT_EVENT_RENEW; |
| |
| client->lease = sd_dhcp_lease_unref(client->lease); |
| } |
| |
| client->lease = TAKE_PTR(lease); |
| |
| 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 > 0); |
| |
| if (lifetime > 3) |
| lifetime -= 3; |
| else |
| lifetime = 0; |
| |
| return client->request_sent + (lifetime * 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); |
| |
| /* don't set timers for infinite leases */ |
| if (client->lease->lifetime == 0xffffffff) { |
| (void) event_source_disable(client->timeout_t1); |
| (void) event_source_disable(client->timeout_t2); |
| (void) event_source_disable(client->timeout_expire); |
| |
| return 0; |
| } |
| |
| r = sd_event_now(client->event, clock_boottime_or_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 > 0 && client->lease->t2 > 0) { |
| /* 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 > 0 && 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 > 0 && 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 = event_reset_time(client->event, &client->timeout_expire, |
| clock_boottime_or_monotonic(), |
| lifetime_timeout, 10 * USEC_PER_MSEC, |
| client_timeout_expire, client, |
| client->event_priority, "dhcp4-lifetime", true); |
| if (r < 0) |
| return r; |
| |
| log_dhcp_client(client, "lease expires in %s", |
| format_timespan(time_string, FORMAT_TIMESPAN_MAX, lifetime_timeout - time_now, USEC_PER_SEC)); |
| |
| /* don't arm earlier timeouts if this has already expired */ |
| if (lifetime_timeout <= time_now) |
| return 0; |
| |
| /* arm T2 timeout */ |
| r = event_reset_time(client->event, &client->timeout_t2, |
| clock_boottime_or_monotonic(), |
| t2_timeout, 10 * USEC_PER_MSEC, |
| client_timeout_t2, client, |
| client->event_priority, "dhcp4-t2-timeout", true); |
| if (r < 0) |
| return r; |
| |
| log_dhcp_client(client, "T2 expires in %s", |
| format_timespan(time_string, FORMAT_TIMESPAN_MAX, t2_timeout - time_now, USEC_PER_SEC)); |
| |
| /* don't arm earlier timeout if this has already expired */ |
| if (t2_timeout <= time_now) |
| return 0; |
| |
| /* arm T1 timeout */ |
| r = event_reset_time(client->event, &client->timeout_t1, |
| clock_boottime_or_monotonic(), |
| t1_timeout, 10 * USEC_PER_MSEC, |
| client_timeout_t1, client, |
| client->event_priority, "dhcp4-t1-timer", true); |
| if (r < 0) |
| return r; |
| |
| log_dhcp_client(client, "T1 expires in %s", |
| format_timespan(time_string, FORMAT_TIMESPAN_MAX, t1_timeout - time_now, USEC_PER_SEC)); |
| |
| return 0; |
| } |
| |
| static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message, int len) { |
| DHCP_CLIENT_DONT_DESTROY(client); |
| char time_string[FORMAT_TIMESPAN_MAX]; |
| int r = 0, notify_event = 0; |
| |
| assert(client); |
| assert(client->event); |
| assert(message); |
| |
| switch (client->state) { |
| case DHCP_STATE_SELECTING: |
| |
| r = client_handle_offer(client, message, len); |
| if (r >= 0) { |
| |
| client->state = DHCP_STATE_REQUESTING; |
| client->attempt = 1; |
| |
| r = event_reset_time(client->event, &client->timeout_resend, |
| clock_boottime_or_monotonic(), |
| 0, 0, |
| client_timeout_resend, client, |
| client->event_priority, "dhcp4-resend-timer", true); |
| 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 >= 0) { |
| client->start_delay = 0; |
| (void) event_source_disable(client->timeout_resend); |
| client->receive_message = |
| sd_event_source_unref(client->receive_message); |
| client->fd = asynchronous_close(client->fd); |
| |
| if (IN_SET(client->state, DHCP_STATE_REQUESTING, |
| DHCP_STATE_REBOOTING)) |
| notify_event = SD_DHCP_CLIENT_EVENT_IP_ACQUIRE; |
| else if (r != SD_DHCP_CLIENT_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) { |
| log_dhcp_client(client, "could not set lease timeouts"); |
| goto error; |
| } |
| |
| r = dhcp_network_bind_udp_socket(client->ifindex, client->lease->address, client->port); |
| if (r < 0) { |
| log_dhcp_client(client, "could not bind UDP socket"); |
| goto error; |
| } |
| |
| client->fd = r; |
| |
| client_initialize_io_events(client, client_receive_message_udp); |
| |
| if (notify_event) { |
| client_notify(client, notify_event); |
| if (client->state == DHCP_STATE_STOPPED) |
| return 0; |
| } |
| |
| } else if (r == -EADDRNOTAVAIL) { |
| /* got a NAK, let's restart the client */ |
| client_notify(client, SD_DHCP_CLIENT_EVENT_EXPIRED); |
| |
| r = client_initialize(client); |
| if (r < 0) |
| goto error; |
| |
| r = client_start_delayed(client); |
| if (r < 0) |
| goto error; |
| |
| log_dhcp_client(client, "REBOOT in %s", format_timespan(time_string, FORMAT_TIMESPAN_MAX, |
| client->start_delay, USEC_PER_SEC)); |
| |
| client->start_delay = CLAMP(client->start_delay * 2, |
| RESTART_AFTER_NAK_MIN_USEC, RESTART_AFTER_NAK_MAX_USEC); |
| |
| return 0; |
| } else if (r == -ENOMSG) |
| /* invalid message, let's ignore it */ |
| return 0; |
| |
| break; |
| |
| case DHCP_STATE_BOUND: |
| r = client_handle_forcerenew(client, message, len); |
| if (r >= 0) { |
| r = client_timeout_t1(NULL, 0, client); |
| if (r < 0) |
| goto error; |
| } else if (r == -ENOMSG) |
| /* invalid message, let's ignore it */ |
| return 0; |
| |
| break; |
| |
| case DHCP_STATE_INIT: |
| case DHCP_STATE_INIT_REBOOT: |
| |
| break; |
| |
| case DHCP_STATE_STOPPED: |
| r = -EINVAL; |
| goto error; |
| } |
| |
| error: |
| if (r < 0) |
| 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; |
| const uint8_t *expected_chaddr = NULL; |
| uint8_t expected_hlen = 0; |
| ssize_t len, buflen; |
| |
| assert(s); |
| assert(client); |
| |
| buflen = next_datagram_size_fd(fd); |
| if (buflen == -ENETDOWN) { |
| /* the link is down. Don't return an error or the I/O event |
| source will be disconnected and we won't be able to receive |
| packets again when the link comes back. */ |
| return 0; |
| } |
| if (buflen < 0) |
| return buflen; |
| |
| message = malloc0(buflen); |
| if (!message) |
| return -ENOMEM; |
| |
| len = recv(fd, message, buflen, 0); |
| if (len < 0) { |
| /* see comment above for why we shouldn't error out on ENETDOWN. */ |
| if (IN_SET(errno, EAGAIN, EINTR, ENETDOWN)) |
| return 0; |
| |
| return log_dhcp_client_errno(client, errno, |
| "Could not receive message from UDP socket: %m"); |
| } |
| if ((size_t) len < sizeof(DHCPMessage)) { |
| log_dhcp_client(client, "Too small to be a DHCP message: ignoring"); |
| return 0; |
| } |
| |
| 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 (message->htype != client->arp_type) { |
| log_dhcp_client(client, "Packet type does not match client type"); |
| return 0; |
| } |
| |
| if (client->arp_type == ARPHRD_ETHER) { |
| expected_hlen = ETH_ALEN; |
| expected_chaddr = &client->mac_addr[0]; |
| } |
| |
| if (message->hlen != expected_hlen) { |
| log_dhcp_client(client, "Unexpected packet hlen %d", message->hlen); |
| return 0; |
| } |
| |
| if (expected_hlen > 0 && memcmp(&message->chaddr[0], expected_chaddr, expected_hlen)) { |
| log_dhcp_client(client, "Received chaddr does not match expected: ignoring"); |
| return 0; |
| } |
| |
| if (client->state != DHCP_STATE_BOUND && |
| be32toh(message->xid) != client->xid) { |
| /* in BOUND state, we may receive FORCERENEW with xid set by server, |
| so ignore the xid in this case */ |
| log_dhcp_client(client, "Received xid (%u) does not match expected (%u): ignoring", |
| be32toh(message->xid), client->xid); |
| 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; |
| ssize_t buflen, len; |
| int r; |
| |
| assert(s); |
| assert(client); |
| |
| buflen = next_datagram_size_fd(fd); |
| if (buflen == -ENETDOWN) |
| return 0; |
| if (buflen < 0) |
| return buflen; |
| |
| packet = malloc0(buflen); |
| if (!packet) |
| return -ENOMEM; |
| |
| iov = IOVEC_MAKE(packet, buflen); |
| |
| len = recvmsg(fd, &msg, 0); |
| if (len < 0) { |
| if (IN_SET(errno, EAGAIN, EINTR, ENETDOWN)) |
| return 0; |
| |
| return log_dhcp_client_errno(client, errno, |
| "Could not receive message from raw socket: %m"); |
| } else if ((size_t)len < sizeof(DHCPPacket)) |
| return 0; |
| |
| CMSG_FOREACH(cmsg, &msg) |
| 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, client->port); |
| 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; |
| |
| /* RFC7844 section 3.3: |
| SHOULD perform a complete four-way handshake, starting with a |
| DHCPDISCOVER, to obtain a new address lease. If the client can |
| ascertain that this is exactly the same network to which it was |
| previously connected, and if the link-layer address did not change, |
| the client MAY issue a DHCPREQUEST to try to reclaim the current |
| address. */ |
| if (client->last_addr && !client->anonymize) |
| client->state = DHCP_STATE_INIT_REBOOT; |
| |
| r = client_start(client); |
| if (r >= 0) |
| log_dhcp_client(client, "STARTED on ifindex %i", client->ifindex); |
| |
| return r; |
| } |
| |
| int sd_dhcp_client_stop(sd_dhcp_client *client) { |
| DHCP_CLIENT_DONT_DESTROY(client); |
| |
| assert_return(client, -EINVAL); |
| |
| client_stop(client, SD_DHCP_CLIENT_EVENT_STOP); |
| client->state = DHCP_STATE_STOPPED; |
| |
| return 0; |
| } |
| |
| int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event, int64_t 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) { |
| assert_return(client, NULL); |
| |
| return client->event; |
| } |
| |
| static sd_dhcp_client *dhcp_client_free(sd_dhcp_client *client) { |
| assert(client); |
| |
| log_dhcp_client(client, "FREE"); |
| |
| 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_initialize(client); |
| |
| sd_dhcp_client_detach_event(client); |
| |
| sd_dhcp_lease_unref(client->lease); |
| |
| free(client->req_opts); |
| free(client->hostname); |
| free(client->vendor_class_identifier); |
| client->user_class = strv_free(client->user_class); |
| return mfree(client); |
| } |
| |
| DEFINE_TRIVIAL_REF_UNREF_FUNC(sd_dhcp_client, sd_dhcp_client, dhcp_client_free); |
| |
| int sd_dhcp_client_new(sd_dhcp_client **ret, int anonymize) { |
| _cleanup_(sd_dhcp_client_unrefp) sd_dhcp_client *client = NULL; |
| |
| assert_return(ret, -EINVAL); |
| |
| client = new(sd_dhcp_client, 1); |
| if (!client) |
| return -ENOMEM; |
| |
| *client = (sd_dhcp_client) { |
| .n_ref = 1, |
| .state = DHCP_STATE_INIT, |
| .ifindex = -1, |
| .fd = -1, |
| .attempt = 1, |
| .mtu = DHCP_DEFAULT_MIN_SIZE, |
| .port = DHCP_PORT_CLIENT, |
| .anonymize = !!anonymize, |
| }; |
| /* NOTE: this could be moved to a function. */ |
| if (anonymize) { |
| client->req_opts_size = ELEMENTSOF(default_req_opts_anonymize); |
| client->req_opts = memdup(default_req_opts_anonymize, client->req_opts_size); |
| } else { |
| 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 = TAKE_PTR(client); |
| |
| return 0; |
| } |