sd-dhcp-client.c revision 0c79c68d93d721d37ba088fb50dbf07bb0d447e5
/***
This file is part of systemd.
Copyright (C) 2013 Intel Corporation. All rights reserved.
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <net/ethernet.h>
#include <net/if_arp.h>
#include <sys/param.h>
#include <sys/ioctl.h>
#include "util.h"
#include "list.h"
#include "dhcp-protocol.h"
#include "dhcp-internal.h"
#include "dhcp-lease-internal.h"
#include "sd-dhcp-client.h"
struct sd_dhcp_client {
DHCPState state;
sd_event *event;
int event_priority;
sd_event_source *timeout_resend;
int index;
int fd;
union sockaddr_union link;
sd_event_source *receive_message;
uint8_t *req_opts;
size_t req_opts_allocated;
size_t req_opts_size;
be32_t last_addr;
struct {
uint8_t type;
struct ether_addr mac_addr;
} _packed_ client_id;
uint32_t xid;
usec_t start_time;
uint16_t secs;
unsigned int attempt;
usec_t request_sent;
sd_event_source *timeout_t1;
sd_event_source *timeout_t2;
sd_event_source *timeout_expire;
sd_dhcp_client_cb_t cb;
void *userdata;
sd_dhcp_lease *lease;
};
static const uint8_t default_req_opts[] = {
DHCP_OPTION_SUBNET_MASK,
DHCP_OPTION_ROUTER,
DHCP_OPTION_HOST_NAME,
DHCP_OPTION_DOMAIN_NAME,
DHCP_OPTION_DOMAIN_NAME_SERVER,
DHCP_OPTION_NTP_SERVER,
};
static int client_receive_message_raw(sd_event_source *s, int fd,
uint32_t revents, void *userdata);
static int client_receive_message_udp(sd_event_source *s, int fd,
uint32_t revents, void *userdata);
int sd_dhcp_client_set_callback(sd_dhcp_client *client, sd_dhcp_client_cb_t cb,
void *userdata) {
assert_return(client, -EINVAL);
client->cb = cb;
client->userdata = userdata;
return 0;
}
int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option) {
size_t i;
assert_return(client, -EINVAL);
assert_return (client->state == DHCP_STATE_INIT, -EBUSY);
switch(option) {
case DHCP_OPTION_PAD:
case DHCP_OPTION_OVERLOAD:
case DHCP_OPTION_MESSAGE_TYPE:
case DHCP_OPTION_PARAMETER_REQUEST_LIST:
case DHCP_OPTION_END:
return -EINVAL;
default:
break;
}
for (i = 0; i < client->req_opts_size; i++)
if (client->req_opts[i] == option)
return -EEXIST;
if (!GREEDY_REALLOC(client->req_opts, client->req_opts_allocated,
client->req_opts_size + 1))
return -ENOMEM;
client->req_opts[client->req_opts_size++] = option;
return 0;
}
int sd_dhcp_client_set_request_address(sd_dhcp_client *client,
const struct in_addr *last_addr) {
assert_return(client, -EINVAL);
assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
if (last_addr)
client->last_addr = last_addr->s_addr;
else
client->last_addr = INADDR_ANY;
return 0;
}
int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index) {
assert_return(client, -EINVAL);
assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
assert_return(interface_index >= -1, -EINVAL);
client->index = interface_index;
return 0;
}
int sd_dhcp_client_set_mac(sd_dhcp_client *client,
const struct ether_addr *addr) {
bool need_restart = false;
assert_return(client, -EINVAL);
assert_return(addr, -EINVAL);
if (memcmp(&client->client_id.mac_addr, addr, ETH_ALEN) == 0)
return 0;
if (client->state != DHCP_STATE_INIT) {
log_dhcp_client(client, "Changing MAC address on running DHCP "
"client, restarting");
sd_dhcp_client_stop(client);
need_restart = true;
}
memcpy(&client->client_id.mac_addr, addr, ETH_ALEN);
client->client_id.type = 0x01;
if (need_restart)
sd_dhcp_client_start(client);
return 0;
}
int sd_dhcp_client_get_lease(sd_dhcp_client *client, sd_dhcp_lease **ret) {
assert_return(client, -EINVAL);
assert_return(ret, -EINVAL);
if (client->state != DHCP_STATE_BOUND &&
client->state != DHCP_STATE_RENEWING &&
client->state != DHCP_STATE_REBINDING)
return -EADDRNOTAVAIL;
*ret = sd_dhcp_lease_ref(client->lease);
return 0;
}
static int client_notify(sd_dhcp_client *client, int event) {
if (client->cb)
client->cb(client, event, client->userdata);
return 0;
}
static int client_initialize(sd_dhcp_client *client) {
assert_return(client, -EINVAL);
client->receive_message =
sd_event_source_unref(client->receive_message);
client->fd = safe_close(client->fd);
client->timeout_resend = sd_event_source_unref(client->timeout_resend);
client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
client->timeout_expire = sd_event_source_unref(client->timeout_expire);
client->attempt = 1;
client->state = DHCP_STATE_INIT;
client->xid = 0;
if (client->lease)
client->lease = sd_dhcp_lease_unref(client->lease);
return 0;
}
static int client_stop(sd_dhcp_client *client, int error) {
assert_return(client, -EINVAL);
client_notify(client, error);
client_initialize(client);
log_dhcp_client(client, "STOPPED");
return 0;
}
static int client_message_init(sd_dhcp_client *client, DHCPMessage *message,
uint8_t type, uint8_t **opt, size_t *optlen) {
int r;
assert(client);
assert(client->secs);
assert(message);
assert(opt);
assert(optlen);
r = dhcp_message_init(message, BOOTREQUEST, client->xid, type, opt,
optlen);
if (r < 0)
return r;
/* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
refuse to issue an DHCP lease if 'secs' is set to zero */
message->secs = htobe16(client->secs);
memcpy(&message->chaddr, &client->client_id.mac_addr, ETH_ALEN);
if (client->state == DHCP_STATE_RENEWING ||
client->state == DHCP_STATE_REBINDING)
message->ciaddr = client->lease->address;
/* Some DHCP servers will refuse to issue an DHCP lease if the Client
Identifier option is not set */
r = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
sizeof(client->client_id), &client->client_id);
if (r < 0)
return r;
if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
be16_t max_size;
r = dhcp_option_append(opt, optlen,
DHCP_OPTION_PARAMETER_REQUEST_LIST,
client->req_opts_size,
client->req_opts);
if (r < 0)
return r;
/* Some DHCP servers will send bigger DHCP packets than the
defined default size unless the Maximum Messge Size option
is explicitely set */
max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE +
DHCP_MIN_OPTIONS_SIZE);
r = dhcp_option_append(opt, optlen,
DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
2, &max_size);
if (r < 0)
return r;
}
return 0;
}
static int dhcp_client_send_raw(sd_dhcp_client *client, DHCPPacket *packet,
size_t len) {
dhcp_packet_append_ip_headers(packet, INADDR_ANY, DHCP_PORT_CLIENT,
INADDR_BROADCAST, DHCP_PORT_SERVER, len);
return dhcp_network_send_raw_socket(client->fd, &client->link,
packet, len);
}
static int client_send_discover(sd_dhcp_client *client) {
_cleanup_free_ DHCPPacket *discover = NULL;
size_t optlen, len;
uint8_t *opt;
usec_t time_now;
int r;
assert(client);
r = sd_event_now(client->event, CLOCK_MONOTONIC, &time_now);
if (r < 0)
return r;
assert(time_now >= client->start_time);
/* seconds between sending first and last DISCOVER
* must always be strictly positive to deal with broken servers */
client->secs = ((time_now - client->start_time) / USEC_PER_SEC) ? : 1;
optlen = DHCP_MIN_OPTIONS_SIZE;
len = sizeof(DHCPPacket) + optlen;
discover = malloc0(len);
if (!discover)
return -ENOMEM;
r = client_message_init(client, &discover->dhcp, DHCP_DISCOVER,
&opt, &optlen);
if (r < 0)
return r;
if (client->last_addr != INADDR_ANY) {
r = dhcp_option_append(&opt, &optlen,
DHCP_OPTION_REQUESTED_IP_ADDRESS,
4, &client->last_addr);
if (r < 0)
return r;
}
r = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
if (r < 0)
return r;
r = dhcp_client_send_raw(client, discover, len - optlen);
if (r < 0)
return r;
log_dhcp_client(client, "DISCOVER");
return 0;
}
static int client_send_request(sd_dhcp_client *client) {
_cleanup_free_ DHCPPacket *request;
size_t optlen, len;
uint8_t *opt;
int r;
optlen = DHCP_MIN_OPTIONS_SIZE;
len = sizeof(DHCPPacket) + optlen;
request = malloc0(len);
if (!request)
return -ENOMEM;
r = client_message_init(client, &request->dhcp, DHCP_REQUEST, &opt,
&optlen);
if (r < 0)
return r;
switch (client->state) {
case DHCP_STATE_INIT_REBOOT:
r = dhcp_option_append(&opt, &optlen,
DHCP_OPTION_REQUESTED_IP_ADDRESS,
4, &client->last_addr);
if (r < 0)
return r;
break;
case DHCP_STATE_REQUESTING:
r = dhcp_option_append(&opt, &optlen,
DHCP_OPTION_REQUESTED_IP_ADDRESS,
4, &client->lease->address);
if (r < 0)
return r;
r = dhcp_option_append(&opt, &optlen,
DHCP_OPTION_SERVER_IDENTIFIER,
4, &client->lease->server_address);
if (r < 0)
return r;
break;
case DHCP_STATE_INIT:
case DHCP_STATE_SELECTING:
case DHCP_STATE_REBOOTING:
case DHCP_STATE_BOUND:
case DHCP_STATE_RENEWING:
case DHCP_STATE_REBINDING:
break;
}
r = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
if (r < 0)
return r;
if (client->state == DHCP_STATE_RENEWING) {
r = dhcp_network_send_udp_socket(client->fd,
client->lease->server_address,
DHCP_PORT_SERVER,
&request->dhcp,
len - optlen - DHCP_IP_UDP_SIZE);
} else {
r = dhcp_client_send_raw(client, request, len - optlen);
}
if (r < 0)
return r;
log_dhcp_client(client, "REQUEST");
return 0;
}
static int client_timeout_resend(sd_event_source *s, uint64_t usec,
void *userdata) {
sd_dhcp_client *client = userdata;
usec_t next_timeout = 0;
uint64_t time_now;
uint32_t time_left;
int r;
assert(s);
assert(client);
assert(client->event);
r = sd_event_now(client->event, CLOCK_MONOTONIC, &time_now);
if (r < 0)
goto error;
switch (client->state) {
case DHCP_STATE_RENEWING:
time_left = (client->lease->t2 - client->lease->t1) / 2;
if (time_left < 60)
time_left = 60;
next_timeout = time_now + time_left * USEC_PER_SEC;
break;
case DHCP_STATE_REBINDING:
time_left = (client->lease->lifetime - client->lease->t2) / 2;
if (time_left < 60)
time_left = 60;
next_timeout = time_now + time_left * USEC_PER_SEC;
break;
case DHCP_STATE_REBOOTING:
/* start over as we did not receive a timely ack or nak */
client->state = DHCP_STATE_INIT;
client->attempt = 1;
client->xid = random_u32();
/* fall through */
case DHCP_STATE_INIT:
case DHCP_STATE_INIT_REBOOT:
case DHCP_STATE_SELECTING:
case DHCP_STATE_REQUESTING:
case DHCP_STATE_BOUND:
if (client->attempt < 64)
client->attempt *= 2;
next_timeout = time_now + (client->attempt - 1) * USEC_PER_SEC;
break;
}
next_timeout += (random_u32() & 0x1fffff);
client->timeout_resend = sd_event_source_unref(client->timeout_resend);
r = sd_event_add_time(client->event,
&client->timeout_resend,
CLOCK_MONOTONIC,
next_timeout, 10 * USEC_PER_MSEC,
client_timeout_resend, client);
if (r < 0)
goto error;
r = sd_event_source_set_priority(client->timeout_resend,
client->event_priority);
if (r < 0)
goto error;
switch (client->state) {
case DHCP_STATE_INIT:
r = client_send_discover(client);
if (r >= 0) {
client->state = DHCP_STATE_SELECTING;
client->attempt = 1;
} else {
if (client->attempt >= 64)
goto error;
}
break;
case DHCP_STATE_SELECTING:
r = client_send_discover(client);
if (r < 0 && client->attempt >= 64)
goto error;
break;
case DHCP_STATE_INIT_REBOOT:
case DHCP_STATE_REQUESTING:
case DHCP_STATE_RENEWING:
case DHCP_STATE_REBINDING:
r = client_send_request(client);
if (r < 0 && client->attempt >= 64)
goto error;
if (client->state == DHCP_STATE_INIT_REBOOT)
client->state = DHCP_STATE_REBOOTING;
client->request_sent = time_now;
break;
case DHCP_STATE_REBOOTING:
case DHCP_STATE_BOUND:
break;
}
return 0;
error:
client_stop(client, r);
/* Errors were dealt with when stopping the client, don't spill
errors into the event loop handler */
return 0;
}
static int client_initialize_events(sd_dhcp_client *client,
sd_event_io_handler_t io_callback) {
int r;
assert(client);
assert(client->event);
r = sd_event_add_io(client->event, &client->receive_message,
client->fd, EPOLLIN, io_callback,
client);
if (r < 0)
goto error;
r = sd_event_source_set_priority(client->receive_message,
client->event_priority);
if (r < 0)
goto error;
client->timeout_resend = sd_event_source_unref(client->timeout_resend);
r = sd_event_add_time(client->event,
&client->timeout_resend,
CLOCK_MONOTONIC,
0, 0,
client_timeout_resend, client);
if (r < 0)
goto error;
r = sd_event_source_set_priority(client->timeout_resend,
client->event_priority);
error:
if (r < 0)
client_stop(client, r);
return 0;
}
static int client_start(sd_dhcp_client *client) {
int r;
assert_return(client, -EINVAL);
assert_return(client->event, -EINVAL);
assert_return(client->index > 0, -EINVAL);
assert_return(client->fd < 0, -EBUSY);
assert_return(client->xid == 0, -EINVAL);
assert_return(client->state == DHCP_STATE_INIT ||
client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
client->xid = random_u32();
r = dhcp_network_bind_raw_socket(client->index, &client->link);
if (r < 0) {
client_stop(client, r);
return r;
}
client->fd = r;
if (client->state == DHCP_STATE_INIT) {
client->start_time = now(CLOCK_MONOTONIC);
client->secs = 0;
}
log_dhcp_client(client, "STARTED");
return client_initialize_events(client, client_receive_message_raw);
}
static int client_timeout_expire(sd_event_source *s, uint64_t usec,
void *userdata) {
sd_dhcp_client *client = userdata;
log_dhcp_client(client, "EXPIRED");
client_notify(client, DHCP_EVENT_EXPIRED);
/* start over as the lease was lost */
client_initialize(client);
client_start(client);
return 0;
}
static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) {
sd_dhcp_client *client = userdata;
int r;
client->receive_message = sd_event_source_unref(client->receive_message);
client->fd = safe_close(client->fd);
client->state = DHCP_STATE_REBINDING;
client->attempt = 1;
r = dhcp_network_bind_raw_socket(client->index, &client->link);
if (r < 0) {
client_stop(client, r);
return 0;
}
client->fd = r;
log_dhcp_client(client, "TIMEOUT T2");
return client_initialize_events(client, client_receive_message_raw);
}
static int client_timeout_t1(sd_event_source *s, uint64_t usec,
void *userdata) {
sd_dhcp_client *client = userdata;
int r;
client->state = DHCP_STATE_RENEWING;
client->attempt = 1;
r = dhcp_network_bind_udp_socket(client->index,
client->lease->address,
DHCP_PORT_CLIENT);
if (r < 0) {
client_stop(client, r);
return 0;
}
client->fd = r;
log_dhcp_client(client, "TIMEOUT T1");
return client_initialize_events(client, client_receive_message_udp);
}
static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer,
size_t len) {
_cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
int r;
r = dhcp_lease_new(&lease);
if (r < 0)
return r;
r = dhcp_option_parse(offer, len, dhcp_lease_parse_options, lease);
if (r != DHCP_OFFER) {
log_dhcp_client(client, "receieved message was not an OFFER, ignoring");
return -ENOMSG;
}
lease->next_server = offer->siaddr;
lease->address = offer->yiaddr;
if (lease->address == INADDR_ANY ||
lease->server_address == INADDR_ANY ||
lease->lifetime == 0) {
log_dhcp_client(client, "receieved lease lacks address, server "
"address or lease lifetime, ignoring");
return -ENOMSG;
}
if (lease->subnet_mask == INADDR_ANY) {
r = dhcp_lease_set_default_subnet_mask(lease);
if (r < 0) {
log_dhcp_client(client, "receieved lease lacks subnet "
"mask, and a fallback one can not be "
"generated, ignoring");
return -ENOMSG;
}
}
client->lease = lease;
lease = NULL;
log_dhcp_client(client, "OFFER");
return 0;
}
static int client_handle_ack(sd_dhcp_client *client, DHCPMessage *ack,
size_t len) {
_cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
int r;
r = dhcp_lease_new(&lease);
if (r < 0)
return r;
r = dhcp_option_parse(ack, len, dhcp_lease_parse_options, lease);
if (r == DHCP_NAK) {
log_dhcp_client(client, "NAK");
return DHCP_EVENT_NO_LEASE;
}
if (r != DHCP_ACK) {
log_dhcp_client(client, "receieved message was not an ACK, ignoring");
return -ENOMSG;
}
lease->next_server = ack->siaddr;
lease->address = ack->yiaddr;
if (lease->address == INADDR_ANY ||
lease->server_address == INADDR_ANY ||
lease->lifetime == 0) {
log_dhcp_client(client, "receieved lease lacks address, server "
"address or lease lifetime, ignoring");
return -ENOMSG;
}
if (lease->subnet_mask == INADDR_ANY) {
r = dhcp_lease_set_default_subnet_mask(lease);
if (r < 0) {
log_dhcp_client(client, "receieved lease lacks subnet "
"mask, and a fallback one can not be "
"generated, ignoring");
return -ENOMSG;
}
}
r = DHCP_EVENT_IP_ACQUIRE;
if (client->lease) {
if (client->lease->address != lease->address ||
client->lease->subnet_mask != lease->subnet_mask ||
client->lease->router != lease->router) {
r = DHCP_EVENT_IP_CHANGE;
}
client->lease = sd_dhcp_lease_unref(client->lease);
}
client->lease = lease;
lease = NULL;
log_dhcp_client(client, "ACK");
return r;
}
static uint64_t client_compute_timeout(sd_dhcp_client *client,
uint32_t lifetime, double factor) {
assert(client);
assert(client->request_sent);
assert(lifetime);
return client->request_sent + ((lifetime - 3) * USEC_PER_SEC * factor) +
+ (random_u32() & 0x1fffff);
}
static int client_set_lease_timeouts(sd_dhcp_client *client) {
usec_t time_now;
uint64_t lifetime_timeout;
uint64_t t2_timeout;
uint64_t t1_timeout;
char time_string[FORMAT_TIMESPAN_MAX];
int r;
assert(client);
assert(client->event);
assert(client->lease);
assert(client->lease->lifetime);
client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
client->timeout_expire = sd_event_source_unref(client->timeout_expire);
/* don't set timers for infinite leases */
if (client->lease->lifetime == 0xffffffff)
return 0;
r = sd_event_now(client->event, CLOCK_MONOTONIC, &time_now);
if (r < 0)
return r;
assert(client->request_sent <= time_now);
/* convert the various timeouts from relative (secs) to absolute (usecs) */
lifetime_timeout = client_compute_timeout(client, client->lease->lifetime, 1);
if (client->lease->t1 && client->lease->t2) {
/* both T1 and T2 are given */
if (client->lease->t1 < client->lease->t2 &&
client->lease->t2 < client->lease->lifetime) {
/* they are both valid */
t2_timeout = client_compute_timeout(client, client->lease->t2, 1);
t1_timeout = client_compute_timeout(client, client->lease->t1, 1);
} else {
/* discard both */
t2_timeout = client_compute_timeout(client, client->lease->lifetime, 7.0 / 8.0);
client->lease->t2 = (client->lease->lifetime * 7) / 8;
t1_timeout = client_compute_timeout(client, client->lease->lifetime, 0.5);
client->lease->t1 = client->lease->lifetime / 2;
}
} else if (client->lease->t2 && client->lease->t2 < client->lease->lifetime) {
/* only T2 is given, and it is valid */
t2_timeout = client_compute_timeout(client, client->lease->t2, 1);
t1_timeout = client_compute_timeout(client, client->lease->lifetime, 0.5);
client->lease->t1 = client->lease->lifetime / 2;
if (t2_timeout <= t1_timeout) {
/* the computed T1 would be invalid, so discard T2 */
t2_timeout = client_compute_timeout(client, client->lease->lifetime, 7.0 / 8.0);
client->lease->t2 = (client->lease->lifetime * 7) / 8;
}
} else if (client->lease->t1 && client->lease->t1 < client->lease->lifetime) {
/* only T1 is given, and it is valid */
t1_timeout = client_compute_timeout(client, client->lease->t1, 1);
t2_timeout = client_compute_timeout(client, client->lease->lifetime, 7.0 / 8.0);
client->lease->t2 = (client->lease->lifetime * 7) / 8;
if (t2_timeout <= t1_timeout) {
/* the computed T2 would be invalid, so discard T1 */
t2_timeout = client_compute_timeout(client, client->lease->lifetime, 0.5);
client->lease->t2 = client->lease->lifetime / 2;
}
} else {
/* fall back to the default timeouts */
t1_timeout = client_compute_timeout(client, client->lease->lifetime, 0.5);
client->lease->t1 = client->lease->lifetime / 2;
t2_timeout = client_compute_timeout(client, client->lease->lifetime, 7.0 / 8.0);
client->lease->t2 = (client->lease->lifetime * 7) / 8;
}
/* arm lifetime timeout */
r = sd_event_add_time(client->event, &client->timeout_expire,
CLOCK_MONOTONIC,
lifetime_timeout, 10 * USEC_PER_MSEC,
client_timeout_expire, client);
if (r < 0)
return r;
r = sd_event_source_set_priority(client->timeout_expire,
client->event_priority);
if (r < 0)
return r;
log_dhcp_client(client, "lease expires in %s",
format_timespan(time_string, FORMAT_TIMESPAN_MAX,
lifetime_timeout - time_now, 0));
/* don't arm earlier timeouts if this has already expired */
if (lifetime_timeout <= time_now)
return 0;
/* arm T2 timeout */
r = sd_event_add_time(client->event,
&client->timeout_t2,
CLOCK_MONOTONIC,
t2_timeout,
10 * USEC_PER_MSEC,
client_timeout_t2, client);
if (r < 0)
return r;
r = sd_event_source_set_priority(client->timeout_t2,
client->event_priority);
if (r < 0)
return r;
log_dhcp_client(client, "T2 expires in %s",
format_timespan(time_string, FORMAT_TIMESPAN_MAX,
t2_timeout - time_now, 0));
/* don't arm earlier timeout if this has already expired */
if (t2_timeout <= time_now)
return 0;
/* arm T1 timeout */
r = sd_event_add_time(client->event,
&client->timeout_t1,
CLOCK_MONOTONIC,
t1_timeout, 10 * USEC_PER_MSEC,
client_timeout_t1, client);
if (r < 0)
return r;
r = sd_event_source_set_priority(client->timeout_t1,
client->event_priority);
if (r < 0)
return r;
log_dhcp_client(client, "T1 expires in %s",
format_timespan(time_string, FORMAT_TIMESPAN_MAX,
t1_timeout - time_now, 0));
return 0;
}
static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message,
int len) {
int r = 0, notify_event = 0;
assert(client);
assert(client->event);
assert(message);
if (be32toh(message->magic) != DHCP_MAGIC_COOKIE) {
log_dhcp_client(client, "not a DHCP message: ignoring");
return 0;
}
if (message->op != BOOTREPLY) {
log_dhcp_client(client, "not a BOOTREPLY message: ignoring");
return 0;
}
if (be32toh(message->xid) != client->xid) {
log_dhcp_client(client, "received xid (%u) does not match "
"expected (%u): ignoring",
be32toh(message->xid), client->xid);
return 0;
}
if (message->htype != ARPHRD_ETHER || message->hlen != ETHER_ADDR_LEN) {
log_dhcp_client(client, "not an ethernet packet");
return 0;
}
if (memcmp(&message->chaddr[0], &client->client_id.mac_addr,
ETH_ALEN)) {
log_dhcp_client(client, "received chaddr does not match "
"expected: ignoring");
return 0;
}
switch (client->state) {
case DHCP_STATE_SELECTING:
r = client_handle_offer(client, message, len);
if (r >= 0) {
client->timeout_resend =
sd_event_source_unref(client->timeout_resend);
client->state = DHCP_STATE_REQUESTING;
client->attempt = 1;
r = sd_event_add_time(client->event,
&client->timeout_resend,
CLOCK_MONOTONIC,
0, 0,
client_timeout_resend, client);
if (r < 0)
goto error;
r = sd_event_source_set_priority(client->timeout_resend,
client->event_priority);
if (r < 0)
goto error;
} else if (r == -ENOMSG)
/* invalid message, let's ignore it */
return 0;
break;
case DHCP_STATE_REBOOTING:
case DHCP_STATE_REQUESTING:
case DHCP_STATE_RENEWING:
case DHCP_STATE_REBINDING:
r = client_handle_ack(client, message, len);
if (r == DHCP_EVENT_NO_LEASE) {
client->timeout_resend =
sd_event_source_unref(client->timeout_resend);
if (client->state == DHCP_STATE_REBOOTING) {
r = client_initialize(client);
if (r < 0)
goto error;
r = client_start(client);
if (r < 0)
goto error;
}
goto error;
} else if (r >= 0) {
client->timeout_resend =
sd_event_source_unref(client->timeout_resend);
if (IN_SET(client->state, DHCP_STATE_REQUESTING,
DHCP_STATE_REBOOTING))
notify_event = DHCP_EVENT_IP_ACQUIRE;
else if (r != DHCP_EVENT_IP_ACQUIRE)
notify_event = r;
client->state = DHCP_STATE_BOUND;
client->attempt = 1;
client->last_addr = client->lease->address;
r = client_set_lease_timeouts(client);
if (r < 0)
goto error;
if (notify_event)
client_notify(client, notify_event);
client->receive_message =
sd_event_source_unref(client->receive_message);
client->fd = safe_close(client->fd);
} else if (r == -ENOMSG)
/* invalid message, let's ignore it */
return 0;
break;
case DHCP_STATE_INIT:
case DHCP_STATE_INIT_REBOOT:
case DHCP_STATE_BOUND:
break;
}
error:
if (r < 0 || r == DHCP_EVENT_NO_LEASE)
return client_stop(client, r);
return 0;
}
static int client_receive_message_udp(sd_event_source *s, int fd,
uint32_t revents, void *userdata) {
sd_dhcp_client *client = userdata;
_cleanup_free_ DHCPMessage *message = NULL;
int buflen = 0, len, r;
assert(s);
assert(client);
r = ioctl(fd, FIONREAD, &buflen);
if (r < 0 || buflen <= 0)
buflen = sizeof(DHCPMessage) + DHCP_MIN_OPTIONS_SIZE;
message = malloc0(buflen);
if (!message)
return -ENOMEM;
len = read(fd, message, buflen);
if (len < 0) {
log_dhcp_client(client, "could not receive message from UDP "
"socket: %s", strerror(errno));
return 0;
} else if ((size_t)len < sizeof(DHCPMessage))
return 0;
return client_handle_message(client, message, len);
}
static int client_receive_message_raw(sd_event_source *s, int fd,
uint32_t revents, void *userdata) {
sd_dhcp_client *client = userdata;
_cleanup_free_ DHCPPacket *packet = NULL;
uint8_t cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
struct iovec iov = {};
struct msghdr msg = {
.msg_iov = &iov,
.msg_iovlen = 1,
.msg_control = cmsgbuf,
.msg_controllen = sizeof(cmsgbuf),
};
struct cmsghdr *cmsg;
bool checksum = true;
int buflen = 0, len, r;
assert(s);
assert(client);
r = ioctl(fd, FIONREAD, &buflen);
if (r < 0 || buflen <= 0)
buflen = sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE;
packet = malloc0(buflen);
if (!packet)
return -ENOMEM;
iov.iov_base = packet;
iov.iov_len = buflen;
len = recvmsg(fd, &msg, 0);
if (len < 0) {
log_dhcp_client(client, "could not receive message from raw "
"socket: %s", strerror(errno));
return 0;
} else if ((size_t)len < sizeof(DHCPPacket))
return 0;
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
if (cmsg->cmsg_level == SOL_PACKET && cmsg->cmsg_type == PACKET_AUXDATA) {
struct tpacket_auxdata *aux = (void *)CMSG_DATA(cmsg);
checksum = !(aux->tp_status & TP_STATUS_CSUMNOTREADY);
break;
}
}
r = dhcp_packet_verify_headers(packet, len, checksum);
if (r < 0)
return 0;
len -= DHCP_IP_UDP_SIZE;
return client_handle_message(client, &packet->dhcp, len);
}
int sd_dhcp_client_start(sd_dhcp_client *client) {
int r;
assert_return(client, -EINVAL);
r = client_initialize(client);
if (r < 0)
return r;
if (client->last_addr)
client->state = DHCP_STATE_INIT_REBOOT;
return client_start(client);
}
int sd_dhcp_client_stop(sd_dhcp_client *client) {
return client_stop(client, DHCP_EVENT_STOP);
}
int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event,
int priority) {
int r;
assert_return(client, -EINVAL);
assert_return(!client->event, -EBUSY);
if (event)
client->event = sd_event_ref(event);
else {
r = sd_event_default(&client->event);
if (r < 0)
return 0;
}
client->event_priority = priority;
return 0;
}
int sd_dhcp_client_detach_event(sd_dhcp_client *client) {
assert_return(client, -EINVAL);
client->event = sd_event_unref(client->event);
return 0;
}
sd_event *sd_dhcp_client_get_event(sd_dhcp_client *client) {
if (!client)
return NULL;
return client->event;
}
void sd_dhcp_client_free(sd_dhcp_client *client) {
if (!client)
return;
sd_dhcp_client_stop(client);
sd_dhcp_client_detach_event(client);
free(client->req_opts);
free(client);
}
DEFINE_TRIVIAL_CLEANUP_FUNC(sd_dhcp_client*, sd_dhcp_client_free);
#define _cleanup_dhcp_client_free_ _cleanup_(sd_dhcp_client_freep)
int sd_dhcp_client_new(sd_dhcp_client **ret) {
_cleanup_dhcp_client_free_ sd_dhcp_client *client = NULL;
assert_return(ret, -EINVAL);
client = new0(sd_dhcp_client, 1);
if (!client)
return -ENOMEM;
client->state = DHCP_STATE_INIT;
client->index = -1;
client->fd = -1;
client->attempt = 1;
client->req_opts_size = ELEMENTSOF(default_req_opts);
client->req_opts = memdup(default_req_opts, client->req_opts_size);
if (!client->req_opts)
return -ENOMEM;
*ret = client;
client = NULL;
return 0;
}