sd-dhcp6-client.c revision d1b0afe3653b4316a6361d204169620726d468a0
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright (C) 2014 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 <errno.h>
#include <string.h>
#include "udev.h"
#include "udev-util.h"
#include "virt.h"
#include "siphash24.h"
#include "util.h"
#include "refcnt.h"
#include "network-internal.h"
#include "sd-dhcp6-client.h"
#include "dhcp6-protocol.h"
#include "dhcp6-internal.h"
#define SYSTEMD_PEN 43793
#define HASH_KEY SD_ID128_MAKE(80,11,8c,c2,fe,4a,03,ee,3e,d6,0c,6f,36,39,14,09)
struct sd_dhcp6_client {
RefCount n_ref;
enum DHCP6State state;
sd_event *event;
int event_priority;
int index;
struct ether_addr mac_addr;
DHCP6IA ia_na;
usec_t retransmit_time;
uint8_t retransmit_count;
sd_event_source *timeout_resend;
sd_event_source *timeout_resend_expire;
sd_dhcp6_client_cb_t cb;
void *userdata;
struct duid_en {
uint16_t type; /* DHCP6_DUID_EN */
uint32_t pen;
uint8_t id[8];
} _packed_ duid;
};
int sd_dhcp6_client_set_callback(sd_dhcp6_client *client,
sd_dhcp6_client_cb_t cb, void *userdata)
{
assert_return(client, -EINVAL);
client->cb = cb;
client->userdata = userdata;
return 0;
}
int sd_dhcp6_client_set_index(sd_dhcp6_client *client, int interface_index)
{
assert_return(client, -EINVAL);
assert_return(interface_index >= -1, -EINVAL);
client->index = interface_index;
return 0;
}
int sd_dhcp6_client_set_mac(sd_dhcp6_client *client,
const struct ether_addr *mac_addr)
{
assert_return(client, -EINVAL);
if (mac_addr)
memcpy(&client->mac_addr, mac_addr, sizeof(client->mac_addr));
else
memset(&client->mac_addr, 0x00, sizeof(client->mac_addr));
return 0;
}
static sd_dhcp6_client *client_notify(sd_dhcp6_client *client, int event) {
if (client->cb) {
client = sd_dhcp6_client_ref(client);
client->cb(client, event, client->userdata);
client = sd_dhcp6_client_unref(client);
}
return client;
}
static int client_initialize(sd_dhcp6_client *client)
{
assert_return(client, -EINVAL);
client->ia_na.timeout_t1 =
sd_event_source_unref(client->ia_na.timeout_t1);
client->ia_na.timeout_t2 =
sd_event_source_unref(client->ia_na.timeout_t2);
client->retransmit_time = 0;
client->retransmit_count = 0;
client->timeout_resend = sd_event_source_unref(client->timeout_resend);
client->timeout_resend_expire =
sd_event_source_unref(client->timeout_resend_expire);
client->state = DHCP6_STATE_STOPPED;
return 0;
}
static sd_dhcp6_client *client_stop(sd_dhcp6_client *client, int error) {
assert_return(client, NULL);
client = client_notify(client, error);
if (client)
client_initialize(client);
return client;
}
static int client_timeout_resend_expire(sd_event_source *s, uint64_t usec,
void *userdata) {
sd_dhcp6_client *client = userdata;
assert(s);
assert(client);
assert(client->event);
client_stop(client, DHCP6_EVENT_RESEND_EXPIRE);
return 0;
}
static usec_t client_timeout_compute_random(usec_t val) {
return val - val / 10 +
(random_u32() % (2 * USEC_PER_SEC)) * val / 10 / USEC_PER_SEC;
}
static int client_timeout_resend(sd_event_source *s, uint64_t usec,
void *userdata) {
int r = 0;
sd_dhcp6_client *client = userdata;
usec_t time_now, init_retransmit_time, max_retransmit_time;
usec_t max_retransmit_duration;
uint8_t max_retransmit_count;
char time_string[FORMAT_TIMESPAN_MAX];
assert(s);
assert(client);
assert(client->event);
client->timeout_resend = sd_event_source_unref(client->timeout_resend);
switch (client->state) {
case DHCP6_STATE_SOLICITATION:
init_retransmit_time = DHCP6_SOL_TIMEOUT;
max_retransmit_time = DHCP6_SOL_MAX_RT;
max_retransmit_count = 0;
max_retransmit_duration = 0;
break;
case DHCP6_STATE_STOPPED:
case DHCP6_STATE_RS:
return 0;
}
if (max_retransmit_count &&
client->retransmit_count >= max_retransmit_count) {
client_stop(client, DHCP6_EVENT_RETRANS_MAX);
return 0;
}
r = sd_event_now(client->event, CLOCK_MONOTONIC, &time_now);
if (r < 0)
goto error;
if (!client->retransmit_time) {
client->retransmit_time =
client_timeout_compute_random(init_retransmit_time);
} else {
if (max_retransmit_time &&
client->retransmit_time > max_retransmit_time / 2)
client->retransmit_time = client_timeout_compute_random(max_retransmit_time);
else
client->retransmit_time += client_timeout_compute_random(client->retransmit_time);
}
log_dhcp6_client(client, "Next retransmission in %s",
format_timespan(time_string, FORMAT_TIMESPAN_MAX,
client->retransmit_time, 0));
r = sd_event_add_time(client->event, &client->timeout_resend,
CLOCK_MONOTONIC,
time_now + client->retransmit_time,
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;
if (max_retransmit_duration && !client->timeout_resend_expire) {
log_dhcp6_client(client, "Max retransmission duration %"PRIu64" secs",
max_retransmit_duration / USEC_PER_SEC);
r = sd_event_add_time(client->event,
&client->timeout_resend_expire,
CLOCK_MONOTONIC,
time_now + max_retransmit_duration,
USEC_PER_SEC,
client_timeout_resend_expire, client);
if (r < 0)
goto error;
r = sd_event_source_set_priority(client->timeout_resend_expire,
client->event_priority);
if (r < 0)
goto error;
}
error:
if (r < 0)
client_stop(client, r);
return 0;
}
static int client_ensure_iaid(sd_dhcp6_client *client) {
const char *name = NULL;
uint64_t id;
assert(client);
if (client->ia_na.id)
return 0;
if (detect_container(NULL) <= 0) {
/* not in a container, udev will be around */
_cleanup_udev_unref_ struct udev *udev;
_cleanup_udev_device_unref_ struct udev_device *device;
char ifindex_str[2 + DECIMAL_STR_MAX(int)];
udev = udev_new();
if (!udev)
return -ENOMEM;
sprintf(ifindex_str, "n%d", client->index);
device = udev_device_new_from_device_id(udev, ifindex_str);
if (!device)
return -errno;
if (udev_device_get_is_initialized(device) <= 0)
/* not yet ready */
return -EBUSY;
name = net_get_name(device);
}
if (name)
siphash24((uint8_t*)&id, name, strlen(name), HASH_KEY.bytes);
else
/* fall back to mac address if no predictable name available */
siphash24((uint8_t*)&id, &client->mac_addr, ETH_ALEN,
HASH_KEY.bytes);
/* fold into 32 bits */
client->ia_na.id = (id & 0xffffffff) ^ (id >> 32);
return 0;
}
static int client_start(sd_dhcp6_client *client)
{
int r;
assert_return(client, -EINVAL);
assert_return(client->event, -EINVAL);
assert_return(client->index > 0, -EINVAL);
r = client_ensure_iaid(client);
if (r < 0)
return r;
client->state = DHCP6_STATE_SOLICITATION;
r = sd_event_add_time(client->event, &client->timeout_resend,
CLOCK_MONOTONIC, 0, 0, client_timeout_resend,
client);
if (r < 0)
return r;
r = sd_event_source_set_priority(client->timeout_resend,
client->event_priority);
if (r < 0)
return r;
return 0;
}
int sd_dhcp6_client_stop(sd_dhcp6_client *client)
{
client_stop(client, DHCP6_EVENT_STOP);
return 0;
}
int sd_dhcp6_client_start(sd_dhcp6_client *client)
{
int r = 0;
assert_return(client, -EINVAL);
assert_return(client->event, -EINVAL);
assert_return(client->index > 0, -EINVAL);
r = client_initialize(client);
if (r < 0)
return r;
return client_start(client);
}
int sd_dhcp6_client_attach_event(sd_dhcp6_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_dhcp6_client_detach_event(sd_dhcp6_client *client) {
assert_return(client, -EINVAL);
client->event = sd_event_unref(client->event);
return 0;
}
sd_event *sd_dhcp6_client_get_event(sd_dhcp6_client *client) {
if (!client)
return NULL;
return client->event;
}
sd_dhcp6_client *sd_dhcp6_client_ref(sd_dhcp6_client *client) {
if (client)
assert_se(REFCNT_INC(client->n_ref) >= 2);
return client;
}
sd_dhcp6_client *sd_dhcp6_client_unref(sd_dhcp6_client *client) {
if (client && REFCNT_DEC(client->n_ref) <= 0) {
client_initialize(client);
sd_dhcp6_client_detach_event(client);
free(client);
return NULL;
}
return client;
}
DEFINE_TRIVIAL_CLEANUP_FUNC(sd_dhcp6_client*, sd_dhcp6_client_unref);
#define _cleanup_dhcp6_client_free_ _cleanup_(sd_dhcp6_client_unrefp)
int sd_dhcp6_client_new(sd_dhcp6_client **ret)
{
_cleanup_dhcp6_client_free_ sd_dhcp6_client *client = NULL;
sd_id128_t machine_id;
int r;
assert_return(ret, -EINVAL);
client = new0(sd_dhcp6_client, 1);
if (!client)
return -ENOMEM;
client->n_ref = REFCNT_INIT;
client->ia_na.type = DHCP6_OPTION_IA_NA;
client->index = -1;
/* initialize DUID */
client->duid.type = htobe16(DHCP6_DUID_EN);
client->duid.pen = htobe32(SYSTEMD_PEN);
r = sd_id128_get_machine(&machine_id);
if (r < 0)
return r;
/* a bit of snake-oil perhaps, but no need to expose the machine-id
directly */
siphash24(client->duid.id, &machine_id, sizeof(machine_id),
HASH_KEY.bytes);
*ret = client;
client = NULL;
return 0;
}