This source file includes following definitions.
- sd_dhcp_client_set_callback
- sd_dhcp_client_set_request_broadcast
- sd_dhcp_client_set_request_option
- sd_dhcp_client_set_request_address
- sd_dhcp_client_set_index
- sd_dhcp_client_set_mac
- sd_dhcp_client_set_hostname
- sd_dhcp_client_set_vendor_class_identifier
- sd_dhcp_client_set_mtu
- sd_dhcp_client_get_lease
- client_notify
- client_initialize
- client_stop
- client_message_init
- dhcp_client_send_raw
- client_send_discover
- client_send_request
- client_timeout_resend
- client_initialize_io_events
- client_initialize_time_events
- client_initialize_events
- client_start
- client_timeout_expire
- client_timeout_t2
- client_timeout_t1
- client_handle_offer
- client_handle_forcerenew
- client_handle_ack
- client_compute_timeout
- client_set_lease_timeouts
- client_handle_message
- client_receive_message_udp
- client_receive_message_raw
- sd_dhcp_client_start
- sd_dhcp_client_stop
- sd_dhcp_client_attach_event
- sd_dhcp_client_detach_event
- sd_dhcp_client_get_event
- sd_dhcp_client_ref
- sd_dhcp_client_unref
- sd_dhcp_client_new
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <net/ethernet.h>
#include <net/if_arp.h>
#include <linux/if_infiniband.h>
#include <netinet/ether.h>
#include <sys/param.h>
#include <sys/ioctl.h>
#include "util.h"
#include "list.h"
#include "refcnt.h"
#include "async.h"
#include "dhcp-protocol.h"
#include "dhcp-internal.h"
#include "dhcp-lease-internal.h"
#include "sd-dhcp-client.h"
#define MAX_MAC_ADDR_LEN INFINIBAND_ALEN
struct sd_dhcp_client {
RefCount n_ref;
DHCPState state;
sd_event *event;
int event_priority;
sd_event_source *timeout_resend;
int index;
int fd;
union sockaddr_union link;
sd_event_source *receive_message;
bool request_broadcast;
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;
uint8_t mac_addr[MAX_MAC_ADDR_LEN];
size_t mac_addr_len;
uint16_t arp_type;
char *hostname;
char *vendor_class_identifier;
uint32_t mtu;
uint32_t xid;
usec_t start_time;
unsigned int attempt;
usec_t request_sent;
sd_event_source *timeout_t1;
sd_event_source *timeout_t2;
sd_event_source *timeout_expire;
sd_dhcp_client_cb_t cb;
void *userdata;
sd_dhcp_lease *lease;
};
static const uint8_t default_req_opts[] = {
DHCP_OPTION_SUBNET_MASK,
DHCP_OPTION_ROUTER,
DHCP_OPTION_HOST_NAME,
DHCP_OPTION_DOMAIN_NAME,
DHCP_OPTION_DOMAIN_NAME_SERVER,
DHCP_OPTION_NTP_SERVER,
};
static int client_receive_message_raw(sd_event_source *s, int fd,
uint32_t revents, void *userdata);
static int client_receive_message_udp(sd_event_source *s, int fd,
uint32_t revents, void *userdata);
static void client_stop(sd_dhcp_client *client, int error);
int sd_dhcp_client_set_callback(sd_dhcp_client *client, sd_dhcp_client_cb_t cb,
void *userdata) {
assert_return(client, -EINVAL);
client->cb = cb;
client->userdata = userdata;
return 0;
}
int sd_dhcp_client_set_request_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 DHCP_OPTION_PAD:
case DHCP_OPTION_OVERLOAD:
case DHCP_OPTION_MESSAGE_TYPE:
case DHCP_OPTION_PARAMETER_REQUEST_LIST:
case DHCP_OPTION_END:
return -EINVAL;
default:
break;
}
for (i = 0; i < client->req_opts_size; i++)
if (client->req_opts[i] == option)
return -EEXIST;
if (!GREEDY_REALLOC(client->req_opts, client->req_opts_allocated,
client->req_opts_size + 1))
return -ENOMEM;
client->req_opts[client->req_opts_size++] = option;
return 0;
}
int sd_dhcp_client_set_request_address(sd_dhcp_client *client,
const struct in_addr *last_addr) {
assert_return(client, -EINVAL);
assert_return (IN_SET(client->state, DHCP_STATE_INIT,
DHCP_STATE_STOPPED), -EBUSY);
if (last_addr)
client->last_addr = last_addr->s_addr;
else
client->last_addr = INADDR_ANY;
return 0;
}
int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index) {
assert_return(client, -EINVAL);
assert_return (IN_SET(client->state, DHCP_STATE_INIT,
DHCP_STATE_STOPPED), -EBUSY);
assert_return(interface_index > 0, -EINVAL);
client->index = interface_index;
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, DHCP_EVENT_STOP);
}
memcpy(&client->mac_addr, addr, addr_len);
client->mac_addr_len = addr_len;
client->arp_type = arp_type;
memcpy(&client->client_id.mac_addr, addr, ETH_ALEN);
client->client_id.type = 0x01;
if (need_restart && client->state != DHCP_STATE_STOPPED)
sd_dhcp_client_start(client);
return 0;
}
int sd_dhcp_client_set_hostname(sd_dhcp_client *client,
const char *hostname) {
char *new_hostname = NULL;
assert_return(client, -EINVAL);
if (streq_ptr(client->hostname, hostname))
return 0;
if (hostname) {
new_hostname = strdup(hostname);
if (!new_hostname)
return -ENOMEM;
}
free(client->hostname);
client->hostname = new_hostname;
return 0;
}
int sd_dhcp_client_set_vendor_class_identifier(sd_dhcp_client *client,
const char *vci) {
char *new_vci = NULL;
assert_return(client, -EINVAL);
new_vci = strdup(vci);
if (!new_vci)
return -ENOMEM;
free(client->vendor_class_identifier);
client->vendor_class_identifier = new_vci;
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);
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 void client_notify(sd_dhcp_client *client, int event) {
if (client->cb)
client->cb(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);
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 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 == DHCP_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;
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(type == DHCP_DISCOVER || type == 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;
r = sd_event_now(client->event, clock_boottime_or_monotonic(), &time_now);
if (r < 0)
return r;
assert(time_now >= client->start_time);
secs = ((time_now - client->start_time) / USEC_PER_SEC) ? : 1;
packet->dhcp.secs = htobe16(secs);
if (client->request_broadcast || client->arp_type != ARPHRD_ETHER)
packet->dhcp.flags = htobe16(0x8000);
if (client->arp_type == ARPHRD_ETHER)
memcpy(&packet->dhcp.chaddr, &client->mac_addr, ETH_ALEN);
r = dhcp_option_append(&packet->dhcp, optlen, &optoffset, 0,
DHCP_OPTION_CLIENT_IDENTIFIER,
sizeof(client->client_id), &client->client_id);
if (r < 0)
return r;
r = dhcp_option_append(&packet->dhcp, optlen, &optoffset, 0,
DHCP_OPTION_PARAMETER_REQUEST_LIST,
client->req_opts_size, client->req_opts);
if (r < 0)
return r;
max_size = htobe16(size);
r = dhcp_option_append(&packet->dhcp, client->mtu, &optoffset, 0,
DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
2, &max_size);
if (r < 0)
return r;
*_optlen = optlen;
*_optoffset = optoffset;
*ret = packet;
packet = NULL;
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 optoffset, optlen;
int r;
assert(client);
assert(client->state == DHCP_STATE_INIT ||
client->state == DHCP_STATE_SELECTING);
r = client_message_init(client, &discover, DHCP_DISCOVER,
&optlen, &optoffset);
if (r < 0)
return r;
if (client->last_addr != INADDR_ANY) {
r = dhcp_option_append(&discover->dhcp, optlen, &optoffset, 0,
DHCP_OPTION_REQUESTED_IP_ADDRESS,
4, &client->last_addr);
if (r < 0)
return r;
}
if (client->hostname) {
r = dhcp_option_append(&discover->dhcp, optlen, &optoffset, 0,
DHCP_OPTION_HOST_NAME,
strlen(client->hostname), client->hostname);
if (r < 0)
return r;
}
if (client->vendor_class_identifier) {
r = dhcp_option_append(&discover->dhcp, optlen, &optoffset, 0,
DHCP_OPTION_VENDOR_CLASS_IDENTIFIER,
strlen(client->vendor_class_identifier),
client->vendor_class_identifier);
if (r < 0)
return r;
}
r = dhcp_option_append(&discover->dhcp, optlen, &optoffset, 0,
DHCP_OPTION_END, 0, NULL);
if (r < 0)
return r;
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;
r = client_message_init(client, &request, DHCP_REQUEST,
&optlen, &optoffset);
if (r < 0)
return r;
switch (client->state) {
case DHCP_STATE_REQUESTING:
r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0,
DHCP_OPTION_SERVER_IDENTIFIER,
4, &client->lease->server_address);
if (r < 0)
return r;
r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0,
DHCP_OPTION_REQUESTED_IP_ADDRESS,
4, &client->lease->address);
if (r < 0)
return r;
break;
case DHCP_STATE_INIT_REBOOT:
r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0,
DHCP_OPTION_REQUESTED_IP_ADDRESS,
4, &client->last_addr);
if (r < 0)
return r;
break;
case DHCP_STATE_RENEWING:
case DHCP_STATE_REBINDING:
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) {
r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0,
DHCP_OPTION_HOST_NAME,
strlen(client->hostname), client->hostname);
if (r < 0)
return r;
}
r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0,
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:
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);
client->timeout_resend = sd_event_source_unref(client->timeout_resend);
r = sd_event_add_time(client->event,
&client->timeout_resend,
clock_boottime_or_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;
r = sd_event_source_set_name(client->timeout_resend,
"dhcp4-resend-timer");
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);
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_name(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) {
int r;
assert(client);
assert(client->event);
client->timeout_resend = sd_event_source_unref(client->timeout_resend);
r = sd_event_add_time(client->event,
&client->timeout_resend,
clock_boottime_or_monotonic(),
0, 0,
client_timeout_resend, client);
if (r < 0)
goto error;
r = sd_event_source_set_priority(client->timeout_resend,
client->event_priority);
r = sd_event_source_set_name(client->timeout_resend,
"dhcp4-resend-timer");
if (r < 0)
goto error;
error:
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(sd_dhcp_client *client) {
int r;
assert_return(client, -EINVAL);
assert_return(client->event, -EINVAL);
assert_return(client->index > 0, -EINVAL);
assert_return(client->fd < 0, -EBUSY);
assert_return(client->xid == 0, -EINVAL);
assert_return(client->state == DHCP_STATE_INIT ||
client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
client->xid = random_u32();
r = dhcp_network_bind_raw_socket(client->index, &client->link,
client->xid, client->mac_addr,
client->mac_addr_len, client->arp_type);
if (r < 0) {
client_stop(client, r);
return r;
}
client->fd = r;
if (client->state == DHCP_STATE_INIT || client->state == DHCP_STATE_INIT_REBOOT)
client->start_time = now(clock_boottime_or_monotonic());
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;
DHCP_CLIENT_DONT_DESTROY(client);
log_dhcp_client(client, "EXPIRED");
client_notify(client, DHCP_EVENT_EXPIRED);
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;
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->index, &client->link,
client->xid, client->mac_addr,
client->mac_addr_len, client->arp_type);
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_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, "received 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, "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 can not be "
"generated, ignoring");
return -ENOMSG;
}
}
sd_dhcp_lease_unref(client->lease);
client->lease = lease;
lease = NULL;
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);
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_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 -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 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;
} else
r = DHCP_EVENT_RENEW;
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);
if (client->lease->lifetime == 0xffffffff)
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);
lifetime_timeout = client_compute_timeout(client, client->lease->lifetime, 1);
if (client->lease->t1 && client->lease->t2) {
if (client->lease->t1 < client->lease->t2 &&
client->lease->t2 < client->lease->lifetime) {
t2_timeout = client_compute_timeout(client, client->lease->t2, 1);
t1_timeout = client_compute_timeout(client, client->lease->t1, 1);
} else {
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) {
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) {
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) {
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) {
t2_timeout = client_compute_timeout(client, client->lease->lifetime, 0.5);
client->lease->t2 = client->lease->lifetime / 2;
}
} else {
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;
}
r = sd_event_add_time(client->event, &client->timeout_expire,
clock_boottime_or_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;
r = sd_event_source_set_name(client->timeout_expire,
"dhcp4-lifetime");
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));
if (lifetime_timeout <= time_now)
return 0;
r = sd_event_add_time(client->event,
&client->timeout_t2,
clock_boottime_or_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;
r = sd_event_source_set_name(client->timeout_t2,
"dhcp4-t2-timeout");
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));
if (t2_timeout <= time_now)
return 0;
r = sd_event_add_time(client->event,
&client->timeout_t1,
clock_boottime_or_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;
r = sd_event_source_set_name(client->timeout_t1,
"dhcp4-t1-timer");
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) {
DHCP_CLIENT_DONT_DESTROY(client);
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->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_boottime_or_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;
r = sd_event_source_set_name(client->timeout_resend,
"dhcp4-resend-timer");
if (r < 0)
goto error;
} else if (r == -ENOMSG)
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->timeout_resend =
sd_event_source_unref(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 = 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;
r = dhcp_network_bind_udp_socket(client->lease->address,
DHCP_PORT_CLIENT);
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) {
client->timeout_resend =
sd_event_source_unref(client->timeout_resend);
r = client_initialize(client);
if (r < 0)
goto error;
r = client_start(client);
if (r < 0)
goto error;
log_dhcp_client(client, "REBOOTED");
return 0;
} else if (r == -ENOMSG)
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)
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;
int buflen = 0, len, r;
const struct ether_addr zero_mac = { { 0, 0, 0, 0, 0, 0 } };
const struct ether_addr *expected_chaddr = NULL;
uint8_t expected_hlen = 0;
assert(s);
assert(client);
r = ioctl(fd, FIONREAD, &buflen);
if (r < 0)
return r;
if (buflen < 0)
return -EIO;
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: %m");
return 0;
} else 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 {
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) {
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;
int buflen = 0, len, r;
assert(s);
assert(client);
r = ioctl(fd, FIONREAD, &buflen);
if (r < 0)
return r;
if (buflen < 0)
return -EIO;
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: %m");
return 0;
} else if ((size_t)len < sizeof(DHCPPacket))
return 0;
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
if (cmsg->cmsg_level == SOL_PACKET &&
cmsg->cmsg_type == PACKET_AUXDATA &&
cmsg->cmsg_len == CMSG_LEN(sizeof(struct tpacket_auxdata))) {
struct tpacket_auxdata *aux = (struct tpacket_auxdata*)CMSG_DATA(cmsg);
checksum = !(aux->tp_status & TP_STATUS_CSUMNOTREADY);
break;
}
}
r = dhcp_packet_verify_headers(packet, len, checksum);
if (r < 0)
return 0;
len -= DHCP_IP_UDP_SIZE;
return client_handle_message(client, &packet->dhcp, len);
}
int sd_dhcp_client_start(sd_dhcp_client *client) {
int r;
assert_return(client, -EINVAL);
r = client_initialize(client);
if (r < 0)
return r;
if (client->last_addr)
client->state = DHCP_STATE_INIT_REBOOT;
r = client_start(client);
if (r >= 0)
log_dhcp_client(client, "STARTED on ifindex %u", client->index);
return r;
}
int sd_dhcp_client_stop(sd_dhcp_client *client) {
DHCP_CLIENT_DONT_DESTROY(client);
assert_return(client, -EINVAL);
client_stop(client, DHCP_EVENT_STOP);
client->state = DHCP_STATE_STOPPED;
return 0;
}
int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event,
int priority) {
int r;
assert_return(client, -EINVAL);
assert_return(!client->event, -EBUSY);
if (event)
client->event = sd_event_ref(event);
else {
r = sd_event_default(&client->event);
if (r < 0)
return 0;
}
client->event_priority = priority;
return 0;
}
int sd_dhcp_client_detach_event(sd_dhcp_client *client) {
assert_return(client, -EINVAL);
client->event = sd_event_unref(client->event);
return 0;
}
sd_event *sd_dhcp_client_get_event(sd_dhcp_client *client) {
if (!client)
return NULL;
return client->event;
}
sd_dhcp_client *sd_dhcp_client_ref(sd_dhcp_client *client) {
if (client)
assert_se(REFCNT_INC(client->n_ref) >= 2);
return client;
}
sd_dhcp_client *sd_dhcp_client_unref(sd_dhcp_client *client) {
if (client && REFCNT_DEC(client->n_ref) <= 0) {
log_dhcp_client(client, "FREE");
client_initialize(client);
client->receive_message =
sd_event_source_unref(client->receive_message);
sd_dhcp_client_detach_event(client);
sd_dhcp_lease_unref(client->lease);
free(client->req_opts);
free(client->hostname);
free(client->vendor_class_identifier);
free(client);
}
return NULL;
}
int sd_dhcp_client_new(sd_dhcp_client **ret) {
_cleanup_dhcp_client_unref_ sd_dhcp_client *client = NULL;
assert_return(ret, -EINVAL);
client = new0(sd_dhcp_client, 1);
if (!client)
return -ENOMEM;
client->n_ref = REFCNT_INIT;
client->state = DHCP_STATE_INIT;
client->index = -1;
client->fd = -1;
client->attempt = 1;
client->mtu = DHCP_DEFAULT_MIN_SIZE;
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;
}