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platform_system_core/libnetutils/dhcp_utils.c

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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 char DHCP_CONFIG_PATH[] = "/system/etc/dhcpcd/dhcpcd.conf";
static const int NAP_TIME = 200; /* wait for 200ms at a time */
/* when polling for property values */
static const char DAEMON_NAME_RENEW[] = "iprenew";
static char errmsg[100];
/* interface length for dhcpcd daemon start (dhcpcd_<interface> as defined in init.rc file)
* or for filling up system properties dhcpcd.<interface>.ipaddress, dhcpcd.<interface>.dns1
* and other properties on a successful bind
*/
#define MAX_INTERFACE_LENGTH 25
/*
* P2p interface names increase sequentially p2p-p2p0-1, p2p-p2p0-2.. after
* group formation. This does not work well with system properties which can quickly
* exhaust or for specifiying a dhcp start target in init which requires
* interface to be pre-defined in init.rc file.
*
* This function returns a common string p2p for all p2p interfaces.
*/
void get_p2p_interface_replacement(const char *interface, char *p2p_interface) {
/* Use p2p for any interface starting with p2p. */
if (strncmp(interface, "p2p",3) == 0) {
strncpy(p2p_interface, "p2p", MAX_INTERFACE_LENGTH);
} else {
strncpy(p2p_interface, interface, MAX_INTERFACE_LENGTH);
}
}
/*
* 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 *dns[],
char *server,
uint32_t *lease,
char *vendorInfo,
char *domain,
char *mtu)
{
char prop_name[PROPERTY_KEY_MAX];
char prop_value[PROPERTY_VALUE_MAX];
/* Interface name after converting p2p0-p2p0-X to p2p to reuse system properties */
char p2p_interface[MAX_INTERFACE_LENGTH];
int x;
get_p2p_interface_replacement(interface, p2p_interface);
snprintf(prop_name, sizeof(prop_name), "%s.%s.ipaddress", DHCP_PROP_NAME_PREFIX, p2p_interface);
property_get(prop_name, ipaddr, NULL);
snprintf(prop_name, sizeof(prop_name), "%s.%s.gateway", DHCP_PROP_NAME_PREFIX, p2p_interface);
property_get(prop_name, gateway, NULL);
snprintf(prop_name, sizeof(prop_name), "%s.%s.server", DHCP_PROP_NAME_PREFIX, p2p_interface);
property_get(prop_name, server, NULL);
//TODO: Handle IPv6 when we change system property usage
if (gateway[0] == '\0' || strncmp(gateway, "0.0.0.0", 7) == 0) {
//DHCP server is our best bet as gateway
strncpy(gateway, server, PROPERTY_VALUE_MAX);
}
snprintf(prop_name, sizeof(prop_name), "%s.%s.mask", DHCP_PROP_NAME_PREFIX, p2p_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;
}
for (x=0; dns[x] != NULL; x++) {
snprintf(prop_name, sizeof(prop_name), "%s.%s.dns%d", DHCP_PROP_NAME_PREFIX, p2p_interface, x+1);
property_get(prop_name, dns[x], NULL);
}
snprintf(prop_name, sizeof(prop_name), "%s.%s.leasetime", DHCP_PROP_NAME_PREFIX, p2p_interface);
if (property_get(prop_name, prop_value, NULL)) {
*lease = atol(prop_value);
}
snprintf(prop_name, sizeof(prop_name), "%s.%s.vendorInfo", DHCP_PROP_NAME_PREFIX,
p2p_interface);
property_get(prop_name, vendorInfo, NULL);
snprintf(prop_name, sizeof(prop_name), "%s.%s.domain", DHCP_PROP_NAME_PREFIX,
p2p_interface);
property_get(prop_name, domain, NULL);
snprintf(prop_name, sizeof(prop_name), "%s.%s.mtu", DHCP_PROP_NAME_PREFIX,
p2p_interface);
property_get(prop_name, mtu, NULL);
return 0;
}
/*
* Start the dhcp client daemon, and wait for it to finish
* configuring the interface.
*
* The device init.rc file needs a corresponding entry for this work.
*
* Example:
* service dhcpcd_<interface> /system/bin/dhcpcd -ABKL -f dhcpcd.conf
*/
int dhcp_do_request(const char *interface,
char *ipaddr,
char *gateway,
uint32_t *prefixLength,
char *dns[],
char *server,
uint32_t *lease,
char *vendorInfo,
char *domain,
char *mtu)
{
char result_prop_name[PROPERTY_KEY_MAX];
char daemon_prop_name[PROPERTY_KEY_MAX];
char prop_value[PROPERTY_VALUE_MAX] = {'\0'};
char daemon_cmd[PROPERTY_VALUE_MAX * 2 + sizeof(DHCP_CONFIG_PATH)];
const char *ctrl_prop = "ctl.start";
const char *desired_status = "running";
/* Interface name after converting p2p0-p2p0-X to p2p to reuse system properties */
char p2p_interface[MAX_INTERFACE_LENGTH];
get_p2p_interface_replacement(interface, p2p_interface);
snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",
DHCP_PROP_NAME_PREFIX,
p2p_interface);
snprintf(daemon_prop_name, sizeof(daemon_prop_name), "%s_%s",
DAEMON_PROP_NAME,
p2p_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_%s:-f %s -h %s %s", DAEMON_NAME,
p2p_interface, DHCP_CONFIG_PATH, prop_value, interface);
else
snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s:-f %s %s", DAEMON_NAME,
p2p_interface, DHCP_CONFIG_PATH, 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) {
if (fill_ip_info(interface, ipaddr, gateway, prefixLength, dns,
server, lease, vendorInfo, domain, mtu) == -1) {
return -1;
}
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];
char daemon_prop_name[PROPERTY_KEY_MAX];
char daemon_cmd[PROPERTY_VALUE_MAX * 2];
const char *ctrl_prop = "ctl.stop";
const char *desired_status = "stopped";
char p2p_interface[MAX_INTERFACE_LENGTH];
get_p2p_interface_replacement(interface, p2p_interface);
snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",
DHCP_PROP_NAME_PREFIX,
p2p_interface);
snprintf(daemon_prop_name, sizeof(daemon_prop_name), "%s_%s",
DAEMON_PROP_NAME,
p2p_interface);
snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s", DAEMON_NAME, p2p_interface);
/* Stop the daemon and wait until it's reported to be stopped */
property_set(ctrl_prop, daemon_cmd);
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)
{
char daemon_prop_name[PROPERTY_KEY_MAX];
char daemon_cmd[PROPERTY_VALUE_MAX * 2];
const char *ctrl_prop = "ctl.stop";
const char *desired_status = "stopped";
char p2p_interface[MAX_INTERFACE_LENGTH];
get_p2p_interface_replacement(interface, p2p_interface);
snprintf(daemon_prop_name, sizeof(daemon_prop_name), "%s_%s",
DAEMON_PROP_NAME,
p2p_interface);
snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s", DAEMON_NAME, p2p_interface);
/* Stop the daemon and wait until it's reported to be stopped */
property_set(ctrl_prop, daemon_cmd);
if (wait_for_property(daemon_prop_name, desired_status, 5) < 0) {
return -1;
}
return 0;
}
char *dhcp_get_errmsg() {
return errmsg;
}
/**
* The device init.rc file needs a corresponding entry.
*
* Example:
* service iprenew_<interface> /system/bin/dhcpcd -n
*
*/
int dhcp_do_request_renew(const char *interface,
char *ipaddr,
char *gateway,
uint32_t *prefixLength,
char *dns[],
char *server,
uint32_t *lease,
char *vendorInfo,
char *domain,
char *mtu)
{
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";
char p2p_interface[MAX_INTERFACE_LENGTH];
get_p2p_interface_replacement(interface, p2p_interface);
snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",
DHCP_PROP_NAME_PREFIX,
p2p_interface);
/* Erase any previous setting of the dhcp result property */
property_set(result_prop_name, "");
/* Start the renew daemon and wait until it's ready */
snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s:%s", DAEMON_NAME_RENEW,
p2p_interface, interface);
memset(prop_value, '\0', PROPERTY_VALUE_MAX);
property_set(ctrl_prop, daemon_cmd);
/* 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 Renew 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 Renew result property was not set");
return -1;
}
if (strcmp(prop_value, "ok") == 0) {
return fill_ip_info(interface, ipaddr, gateway, prefixLength, dns,
server, lease, vendorInfo, domain, mtu);
} else {
snprintf(errmsg, sizeof(errmsg), "DHCP Renew result was %s", prop_value);
return -1;
}
}
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