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-rw-r--r--src/libsystemd-network/sd-dhcp-client.c1945
1 files changed, 1945 insertions, 0 deletions
diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c
new file mode 100644
index 0000000..35fc88e
--- /dev/null
+++ b/src/libsystemd-network/sd-dhcp-client.c
@@ -0,0 +1,1945 @@
+/* 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 "random-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "util.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 struct ether_addr zero_mac = {};
+ const struct ether_addr *expected_chaddr = NULL;
+ uint8_t expected_hlen = 0;
+ ssize_t len, buflen;
+
+ assert(s);
+ assert(client);
+
+ buflen = next_datagram_size_fd(fd);
+ if (buflen < 0)
+ return buflen;
+
+ message = malloc0(buflen);
+ if (!message)
+ return -ENOMEM;
+
+ len = recv(fd, message, buflen, 0);
+ if (len < 0) {
+ if (IN_SET(errno, EAGAIN, EINTR))
+ 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 = (const struct ether_addr *) &client->mac_addr;
+ } else {
+ /* Non-Ethernet links expect zero chaddr */
+ expected_hlen = 0;
+ expected_chaddr = &zero_mac;
+ }
+
+ if (message->hlen != expected_hlen) {
+ log_dhcp_client(client, "Unexpected packet hlen %d", message->hlen);
+ return 0;
+ }
+
+ if (memcmp(&message->chaddr[0], expected_chaddr, ETH_ALEN)) {
+ 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 < 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))
+ 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;
+}