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/*
* Copyright 2008, The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* Utilities for managing the dhcpcd DHCP client daemon */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <cutils/properties.h>
static const char DAEMON_NAME[] = "dhcpcd";
static const char DAEMON_PROP_NAME[] = "init.svc.dhcpcd";
static const char HOSTNAME_PROP_NAME[] = "net.hostname";
static const char DHCP_PROP_NAME_PREFIX[] = "dhcp";
static const int NAP_TIME = 200; /* wait for 200ms at a time */
/* when polling for property values */
static char errmsg[100];
/*
* Wait for a system property to be assigned a specified value.
* If desired_value is NULL, then just wait for the property to
* be created with any value. maxwait is the maximum amount of
* time in seconds to wait before giving up.
*/
static int wait_for_property(const char *name, const char *desired_value, int maxwait)
{
char value[PROPERTY_VALUE_MAX] = {'\0'};
int maxnaps = (maxwait * 1000) / NAP_TIME;
if (maxnaps < 1) {
maxnaps = 1;
}
while (maxnaps-- > 0) {
usleep(NAP_TIME * 1000);
if (property_get(name, value, NULL)) {
if (desired_value == NULL ||
strcmp(value, desired_value) == 0) {
return 0;
}
}
}
return -1; /* failure */
}
static int fill_ip_info(const char *interface,
char *ipaddr,
char *gateway,
uint32_t *prefixLength,
char *dns1,
char *dns2,
char *server,
uint32_t *lease)
{
char prop_name[PROPERTY_KEY_MAX];
char prop_value[PROPERTY_VALUE_MAX];
snprintf(prop_name, sizeof(prop_name), "%s.%s.ipaddress", DHCP_PROP_NAME_PREFIX, interface);
property_get(prop_name, ipaddr, NULL);
snprintf(prop_name, sizeof(prop_name), "%s.%s.gateway", DHCP_PROP_NAME_PREFIX, interface);
property_get(prop_name, gateway, NULL);
snprintf(prop_name, sizeof(prop_name), "%s.%s.mask", DHCP_PROP_NAME_PREFIX, interface);
if (property_get(prop_name, prop_value, NULL)) {
int p;
// this conversion is v4 only, but this dhcp client is v4 only anyway
in_addr_t mask = ntohl(inet_addr(prop_value));
// Check netmask is a valid IP address. ntohl gives NONE response (all 1's) for
// non 255.255.255.255 inputs. if we get that value check if it is legit..
if (mask == INADDR_NONE && strcmp(prop_value, "255.255.255.255") != 0) {
snprintf(errmsg, sizeof(errmsg), "DHCP gave invalid net mask %s", prop_value);
return -1;
}
for (p = 0; p < 32; p++) {
if (mask == 0) break;
// check for non-contiguous netmask, e.g., 255.254.255.0
if ((mask & 0x80000000) == 0) {
snprintf(errmsg, sizeof(errmsg), "DHCP gave invalid net mask %s", prop_value);
return -1;
}
mask = mask << 1;
}
*prefixLength = p;
}
snprintf(prop_name, sizeof(prop_name), "%s.%s.dns1", DHCP_PROP_NAME_PREFIX, interface);
property_get(prop_name, dns1, NULL);
snprintf(prop_name, sizeof(prop_name), "%s.%s.dns2", DHCP_PROP_NAME_PREFIX, interface);
property_get(prop_name, dns2, NULL);
snprintf(prop_name, sizeof(prop_name), "%s.%s.server", DHCP_PROP_NAME_PREFIX, interface);
property_get(prop_name, server, NULL);
snprintf(prop_name, sizeof(prop_name), "%s.%s.leasetime", DHCP_PROP_NAME_PREFIX, interface);
if (property_get(prop_name, prop_value, NULL)) {
*lease = atol(prop_value);
}
return 0;
}
static const char *ipaddr_to_string(in_addr_t addr)
{
struct in_addr in_addr;
in_addr.s_addr = addr;
return inet_ntoa(in_addr);
}
/*
* Start the dhcp client daemon, and wait for it to finish
* configuring the interface.
*/
int dhcp_do_request(const char *interface,
char *ipaddr,
char *gateway,
uint32_t *prefixLength,
char *dns1,
char *dns2,
char *server,
uint32_t *lease)
{
char result_prop_name[PROPERTY_KEY_MAX];
char prop_value[PROPERTY_VALUE_MAX] = {'\0'};
char daemon_cmd[PROPERTY_VALUE_MAX * 2];
const char *ctrl_prop = "ctl.start";
const char *desired_status = "running";
snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",
DHCP_PROP_NAME_PREFIX,
interface);
/* Erase any previous setting of the dhcp result property */
property_set(result_prop_name, "");
/* Start the daemon and wait until it's ready */
if (property_get(HOSTNAME_PROP_NAME, prop_value, NULL) && (prop_value[0] != '\0'))
snprintf(daemon_cmd, sizeof(daemon_cmd), "%s:-h %s %s", DAEMON_NAME,
prop_value, interface);
else
snprintf(daemon_cmd, sizeof(daemon_cmd), "%s:%s", DAEMON_NAME, interface);
memset(prop_value, '\0', PROPERTY_VALUE_MAX);
property_set(ctrl_prop, daemon_cmd);
if (wait_for_property(DAEMON_PROP_NAME, desired_status, 10) < 0) {
snprintf(errmsg, sizeof(errmsg), "%s", "Timed out waiting for dhcpcd to start");
return -1;
}
/* Wait for the daemon to return a result */
if (wait_for_property(result_prop_name, NULL, 30) < 0) {
snprintf(errmsg, sizeof(errmsg), "%s", "Timed out waiting for DHCP to finish");
return -1;
}
if (!property_get(result_prop_name, prop_value, NULL)) {
/* shouldn't ever happen, given the success of wait_for_property() */
snprintf(errmsg, sizeof(errmsg), "%s", "DHCP result property was not set");
return -1;
}
if (strcmp(prop_value, "ok") == 0) {
char dns_prop_name[PROPERTY_KEY_MAX];
if (fill_ip_info(interface, ipaddr, gateway, prefixLength, dns1, dns2, server, lease)
== -1) {
return -1;
}
/* copy dns data to system properties - TODO - remove this after we have async
* notification of renewal's */
snprintf(dns_prop_name, sizeof(dns_prop_name), "net.%s.dns1", interface);
property_set(dns_prop_name, *dns1 ? ipaddr_to_string(*dns1) : "");
snprintf(dns_prop_name, sizeof(dns_prop_name), "net.%s.dns2", interface);
property_set(dns_prop_name, *dns2 ? ipaddr_to_string(*dns2) : "");
return 0;
} else {
snprintf(errmsg, sizeof(errmsg), "DHCP result was %s", prop_value);
return -1;
}
}
/**
* Stop the DHCP client daemon.
*/
int dhcp_stop(const char *interface)
{
char result_prop_name[PROPERTY_KEY_MAX];
const char *ctrl_prop = "ctl.stop";
const char *desired_status = "stopped";
snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",
DHCP_PROP_NAME_PREFIX,
interface);
/* Stop the daemon and wait until it's reported to be stopped */
property_set(ctrl_prop, DAEMON_NAME);
if (wait_for_property(DAEMON_PROP_NAME, desired_status, 5) < 0) {
return -1;
}
property_set(result_prop_name, "failed");
return 0;
}
/**
* Release the current DHCP client lease.
*/
int dhcp_release_lease(const char *interface)
{
const char *ctrl_prop = "ctl.stop";
const char *desired_status = "stopped";
/* Stop the daemon and wait until it's reported to be stopped */
property_set(ctrl_prop, DAEMON_NAME);
if (wait_for_property(DAEMON_PROP_NAME, desired_status, 5) < 0) {
return -1;
}
return 0;
}
char *dhcp_get_errmsg() {
return errmsg;
}
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