APN的基础知道-安卓
2019-12-23 本文已影响0人
DD_Dog
APN的基础知识
在安卓开发中，尤其是网络开发，可能会经常接触到APN，下面讲解一下相关的基础知识。
一、APN简介
APN的完整说明在3GPP规范TS23.003 Clause 9中进行了详细定义。
MCCMNC的定义在3GPP规范TS23.003 Clause 2的IMSI定义中。
APN在GPRS骨干网中用来标识要使用的外部PDN（Packet data network，分组数据网，即常说的Internet），在GPRS网络中代表外部数据网络的总称。
APN由以下两部分组成：
第一部分：APN网络标识：
是用户通过GGSN/PGW（Gateway GPRS Support Node，GPRS网关支持节点/PDN Gateway ，分组数据网网关）可连接到外部网络的标识，该标识由网络运营者分配给ISP（Internet Service Provider，因特网业务提供者）或公司，与其固定Internet域名一致，是APN的必选组成部分。例如 ， 定义移动用户通过该接入某公司的企业网，则APN的网络标识可以规划为“www.ABC123.com”。
第二部分：APN运营者标识：
用于标识GGSN/PGW所归属的网络，是APN的可选组成部分。其形式为“MNCxxxx.MCCyyyy.gprs”（3G网络中），或者“MNCxxxx.MCCyyyy.3gppnetwork.org（4G网络中）。APN实际上就是对一个外部PDN的标识，这些PDN包括企业内部网、Internet、WAP网站、行业内部网等专用网络。
二．Apn参数的组成
例：移动apn，把所有的属性都放在一起如下
apn carrier=”中国移动彩信 (China Mobile)”
mcc=”460”
mnc=”00”
apn=”cmwap”
proxy=”10.0.0.172”
port=”80”
mmsc=”http://mmsc.monternet.com”
mmsproxy=”10.0.0.172”
mmsport=”80”
user=”mms”
password=”mms”
type=”mms”
authtype=”1”
protocol=”IPV4V6”
/>
其对应的属性定义如下：
- Carrier：apn的名字，可为空，只用来显示apn列表中此apn的显示名字。
- Mcc：由三位数组成。 用于识别移动用户的所在国家;
- Mnc：由两位或三位组成。 用于识别移动用户的归属PLMN。 MNC的长度（两位或三位数）取决于* MCC的值。
- Apn：APN网络标识（接入点名称），是APN参数中的必选组成部分。此标识由运营商分配。
- Proxy：代理服务器的地址
- Port：代理服务器的端口号
- Mmsc：MMS中继服务器/多媒体消息业务中心，是彩信的交换服务器。
- Mmsproxy：彩信代理服务器的地址
- Mmsport：彩信代理服务器的端口号
- Protocol：支持的协议，不配置默认为IPV4。
- User：用户
- Password：密码
-
Authtype：apn的认证协议，PAP为口令认证协议，是二次握手机制。CHAP是质询握手认证协议，是三次握手机制。
image.png
- Type: apn的接入点类型
image.png
注意：此表中的数据连接优先级是由低到高，即default数据连接的优先级最低，而hipri数据连接的优先级最高。比如：手机上网聊天，建立的是default数据连接。如果此时接到一条彩信，由于彩信的数据连接是mms，优先级比default高，所以会先断开default数据连接，建立mms数据连接，让手机先收到彩信。所以收发彩信的同时不能上网。（单条pdp连接的情况）
MCC和MNC：mnc的位数由mcc决定。比如，墨西哥334020，此国家的mnc为020，mccmnc的值都固定在了SIM卡保存的IMSI中，配置apn参数时mnc不可简洁为20，否则apn列表中将读取不到此国家的334020运营商的参数。
三．Apn的存储以及初始化
apn在安卓系统中的存储：
apn文件：system/etc/apn-conf.xml
apn数据存储的数据库：/data/data/com.android.providers.telephony/databases/ telephony.db Carriers表
在安卓源码中的位置：
apn的初始化：
在启动手机时，需要初始化telephony.db数据库，这时候会读取手机目录system/etc/apn-conf.xml并把其中的内容加入到Carriers表中。以后查询有关apn的配置参数都是从Carriers表中取出。
创建并初始化Carriers表：
packages/providers/TelephonyProvider/src/com/android/providers/telephony/TelephonyProvider.java
内部类：DatabaseHelper.java
- 创建数据库
由于添加了UNIQUE 约束条件，如果两个差不多的apn参数满足约束条件内的属性都相等，那么认为是同一组apn参数，将不会重复插入到数据库。
private void createCarriersTable(SQLiteDatabase db, String tableName) {
// Set up the database schema
if (DBG) log("dbh.createCarriersTable start");
String columns = "(_id INTEGER PRIMARY KEY," +
NAME + " TEXT DEFAULT ''," +
NUMERIC + " TEXT DEFAULT ''," +
MCC + " TEXT DEFAULT ''," +
MNC + " TEXT DEFAULT ''," +
APN + " TEXT DEFAULT ''," +
USER + " TEXT DEFAULT ''," +
SERVER + " TEXT DEFAULT ''," +
PASSWORD + " TEXT DEFAULT ''," +
PROXY + " TEXT DEFAULT ''," +
PORT + " TEXT DEFAULT ''," +
MMSPROXY + " TEXT DEFAULT ''," +
MMSPORT + " TEXT DEFAULT ''," +
MMSC + " TEXT DEFAULT ''," +
AUTH_TYPE + " INTEGER DEFAULT -1," +
TYPE + " TEXT DEFAULT ''," +
CURRENT + " INTEGER," +
SOURCE_TYPE + " INTEGER DEFAULT 0," +
CSD_NUM + " TEXT DEFAULT ''," +
PROTOCOL + " TEXT DEFAULT IP," +
ROAMING_PROTOCOL + " TEXT DEFAULT IP,";
/// M: add for OMACP service
if (OMACP_SUPPORT) {
columns += OMACP_ID + " TEXT DEFAULT ''," +
NAP_ID + " TEXT DEFAULT ''," +
PROXY_ID + " TEXT DEFAULT '',";
}
columns += CARRIER_ENABLED + " BOOLEAN DEFAULT 1," +
BEARER + " INTEGER DEFAULT 0," +
BEARER_BITMASK + " INTEGER DEFAULT 0," +
SPN + " TEXT DEFAULT ''," +
IMSI + " TEXT DEFAULT ''," +
PNN + " TEXT DEFAULT ''," +
PPP + " TEXT DEFAULT ''," +
MVNO_TYPE + " TEXT DEFAULT ''," +
MVNO_MATCH_DATA + " TEXT DEFAULT '',";
columns += SUBSCRIPTION_ID + " INTEGER DEFAULT " +
SubscriptionManager.INVALID_SUBSCRIPTION_ID + "," +
PROFILE_ID + " INTEGER DEFAULT 0," +
MODEM_COGNITIVE + " BOOLEAN DEFAULT 0," +
MAX_CONNS + " INTEGER DEFAULT 0," +
WAIT_TIME + " INTEGER DEFAULT 0," +
MAX_CONNS_TIME + " INTEGER DEFAULT 0," +
MTU + " INTEGER DEFAULT 0," +
EDITED + " INTEGER DEFAULT " + UNEDITED + "," +
USER_VISIBLE + " BOOLEAN DEFAULT 1, " +
USER_EDITABLE + " BOOLEAN DEFAULT 1," +
// Uniqueness collisions are used to trigger merge code so if a field is listed
// here it means we will accept both (user edited + new apn_conf definition)
// Columns not included in UNIQUE constraint: name, current, edited,
// user, server, password, authtype, type, protocol, roaming_protocol, sub_id,
// modem_cognitive, max_conns, wait_time, max_conns_time, mtu, bearer_bitmask,
// user_visible
"UNIQUE (" + TextUtils.join(", ", CARRIERS_UNIQUE_FIELDS) + "));";
db.execSQL("CREATE TABLE " + tableName + columns);
db.execSQL("DROP TABLE IF EXISTS " + CARRIERS_DM_TABLE);
db.execSQL("CREATE TABLE " + CARRIERS_DM_TABLE + columns);
if (DBG) log("dbh.createCarriersTable:-");
}
- 读取apns-conf.xml文件，并初始化Carriers表。
private void initDatabase(SQLiteDatabase db) {
if (VDBG) log("dbh.initDatabase:+ db=" + db);
// Read internal APNS data
Resources r = mContext.getResources();
XmlResourceParser parser = r.getXml(com.android.internal.R.xml.apns);
int publicversion = -1;
try {
XmlUtils.beginDocument(parser, "apns");
publicversion = Integer.parseInt(parser.getAttributeValue(null, "version"));
loadApns(db, parser);
} catch (Exception e) {
loge("Got exception while loading APN database." + e);
} finally {
parser.close();
}
// Read external APNS data (partner-provided)
XmlPullParser confparser = null;
File confFile = getApnConfFile();
FileReader confreader = null;
if (DBG) log("confFile = " + confFile);
try {
confreader = new FileReader(confFile);
confparser = Xml.newPullParser();
confparser.setInput(confreader);
XmlUtils.beginDocument(confparser, "apns");
// Sanity check. Force internal version and confidential versions to agree
int confversion = Integer.parseInt(confparser.getAttributeValue(null, "version"));
if (publicversion != confversion) {
log("initDatabase: throwing exception due to version mismatch");
throw new IllegalStateException("Internal APNS file version doesn't match "
+ confFile.getAbsolutePath());
}
db.beginTransaction();
try {
loadApns(db, confparser);
db.setTransactionSuccessful();
} finally {
db.endTransaction();
}
} catch (FileNotFoundException e) {
// It's ok if the file isn't found. It means there isn't a confidential file
// Log.e(TAG, "File not found: '" + confFile.getAbsolutePath() + "'");
} catch (Exception e) {
loge("initDatabase: Exception while parsing '" + confFile.getAbsolutePath() + "'" +
e);
} finally {
// Get rid of user/carrier deleted entries that are not present in apn xml file.
// Those entries have edited value USER_DELETED/CARRIER_DELETED.
if (VDBG) {
log("initDatabase: deleting USER_DELETED and replacing "
+ "DELETED_BUT_PRESENT_IN_XML with DELETED");
}
// Delete USER_DELETED
db.delete(CARRIERS_TABLE, IS_USER_DELETED + " or " + IS_CARRIER_DELETED, null);
// Change USER_DELETED_BUT_PRESENT_IN_XML to USER_DELETED
ContentValues cv = new ContentValues();
cv.put(EDITED, USER_DELETED);
db.update(CARRIERS_TABLE, cv, IS_USER_DELETED_BUT_PRESENT_IN_XML, null);
// Change CARRIER_DELETED_BUT_PRESENT_IN_XML to CARRIER_DELETED
cv = new ContentValues();
cv.put(EDITED, CARRIER_DELETED);
db.update(CARRIERS_TABLE, cv, IS_CARRIER_DELETED_BUT_PRESENT_IN_XML, null);
if (confreader != null) {
try {
confreader.close();
} catch (IOException e) {
// do nothing
}
}
// Update the stored checksum
setApnConfChecksum(getChecksum(confFile));
}
if (VDBG) log("dbh.initDatabase:- db=" + db);
}
- 设置APN：
packages/apps/Settings/src/com/android/settings/ApnSettings.java
查询数据库Carriers表中的数据：
private void fillList() {
final TelephonyManager tm = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
String mccmnc = mSubscriptionInfo == null ? "" : tm.getSimOperator
(mSubscriptionInfo != null ? mSubscriptionInfo.getSubscriptionId()
: SubscriptionManager.INVALID_SUBSCRIPTION_ID);
/// M: for plug-in @{
// use mcc&mnc in IMPI to query apn.
Log.d(TAG, "before plugin, mccmnc = " + mccmnc);
mccmnc = mApnExt.getOperatorNumericFromImpi(mccmnc,
SubscriptionManager.getPhoneId(mSubscriptionInfo.getSubscriptionId()));
/// @}
Log.d(TAG, "mccmnc = " + mccmnc);
/*
StringBuilder where = new StringBuilder("numeric=\"" + mccmnc +
"\" AND NOT (type='ia' AND (apn=\"\" OR apn IS NULL)) AND user_visible!=0");
*/
String where = "numeric=\"" + mccmnc + "\"";
/// M: for [C2K APN Customization] @{
if (mSubscriptionInfo != null) {
int subId = mSubscriptionInfo.getSubscriptionId();
if (CdmaUtils.isSupportCdma(subId)) {
where = CdmaApnSetting.customizeQuerySelectionforCdma(where, mccmnc, subId);
}
}
/// @}
where += " AND NOT (type='ia' AND (apn=\"\" OR apn IS NULL)) AND user_visible!=0";
/// M: for VoLTE, do not show ims apn for non-VoLTE project @{
/*
if (mHideImsApn) {
where.append(" AND NOT (type='ims')");
}
*/
//if (!FeatureOption.MTK_VOLTE_SUPPORT || mHideImsApn) {
where += " AND NOT (type='ims' OR type='ia,ims')";
//}
/// @}
/// M: for plug-in
where = mApnExt.getFillListQuery(where, mccmnc);
Log.d(TAG, "fillList where: " + where);
String order = mApnExt.getApnSortOrder(Telephony.Carriers.DEFAULT_SORT_ORDER);
order = "_id asc";
Log.d(TAG, "fillList sort: " + order);
Cursor cursor = getContentResolver().query(
Telephony.Carriers.CONTENT_URI,
new String[]{"_id", "name", "apn", "type", "mvno_type", "mvno_match_data",
"sourcetype"}, where.toString(), null, order);
if (cursor != null) {
Log.d(TAG, "fillList, cursor count: " + cursor.getCount());
IccRecords r = null;
if (mUiccController != null && mSubscriptionInfo != null) {
r = mUiccController.getIccRecords(SubscriptionManager.getPhoneId(
mSubscriptionInfo.getSubscriptionId()), UiccController.APP_FAM_3GPP);
}
PreferenceGroup apnList = (PreferenceGroup) findPreference("apn_list");
apnList.removeAll();
/// M: for plug-in, use Preference instead ApnPreference for the
// convenience of plug-in side
ArrayList<Preference> mnoApnList = new ArrayList<Preference>();
ArrayList<Preference> mvnoApnList = new ArrayList<Preference>();
ArrayList<Preference> mnoMmsApnList = new ArrayList<Preference>();
ArrayList<Preference> mvnoMmsApnList = new ArrayList<Preference>();
mSelectedKey = getSelectedApnKey();
cursor.moveToFirst();
while (!cursor.isAfterLast()) {
String name = cursor.getString(NAME_INDEX);
String apn = cursor.getString(APN_INDEX);
String key = cursor.getString(ID_INDEX);
String type = cursor.getString(TYPES_INDEX);
String mvnoType = cursor.getString(MVNO_TYPE_INDEX);
String mvnoMatchData = cursor.getString(MVNO_MATCH_DATA_INDEX);
/// M: check source type, some types are not editable
int sourcetype = cursor.getInt(SOURCE_TYPE_INDEX);
/// M: skip specific APN type
if (shouldSkipApn(type)) {
cursor.moveToNext();
continue;
}
/// M: for plug-in
name = mApnExt.updateApnName(name, sourcetype);
ApnPreference pref = new ApnPreference(getPrefContext());
pref.setKey(key);
pref.setTitle(name);
pref.setSummary(apn);
pref.setPersistent(false);
pref.setOnPreferenceChangeListener(this);
pref.setSubId(mSubscriptionInfo.getSubscriptionId());
/// M: for [Read Only APN]
pref.setApnEditable(mApnExt.isAllowEditPresetApn(type, apn, mccmnc, sourcetype));
pref.setSubId(mSubscriptionInfo == null ? null : mSubscriptionInfo
.getSubscriptionId());
/// M: for ALPS02500557, do not select emergency APN
boolean selectable = ((type == null) || (!type.equals("mms")
&& !type.equals("ia") && !type.equals("ims") && !type.equals("emergency")))
/// M: for plug-in
&& mApnExt.isSelectable(type);
pref.setSelectable(selectable);
Log.d(TAG, "mSelectedKey = " + mSelectedKey + " key = " + key + " name = " + name +
" selectable=" + selectable);
if (selectable) {
/// M: select prefer APN later, as the apn list are not solid now @{
/*
if ((mSelectedKey != null) && mSelectedKey.equals(key)) {
pref.setChecked();
}
*/
/// @}
addApnToList(pref, mnoApnList, mvnoApnList, r, mvnoType, mvnoMatchData);
/// M: For CT feature,when apns-conf.xml add type extra value "supl",
// selectable maybe ture when 46011 mms, so need this method.
mApnExt.customizeUnselectableApn(type, mvnoType, mvnoMatchData, mnoApnList, mvnoApnList,
mSubscriptionInfo == null ? null : mSubscriptionInfo
.getSubscriptionId());
} else {
addApnToList(pref, mnoMmsApnList, mvnoMmsApnList, r, mvnoType, mvnoMatchData);
/// M: for plug-in
mApnExt.customizeUnselectableApn(type, mvnoType, mvnoMatchData, mnoMmsApnList, mvnoMmsApn
mSubscriptionInfo == null ? null : mSubscriptionInfo
.getSubscriptionId());
}
cursor.moveToNext();
}
cursor.close();
if (!mvnoApnList.isEmpty()) {
mnoApnList = mvnoApnList;
mnoMmsApnList = mvnoMmsApnList;
// Also save the mvno info
}
for (Preference preference : mnoApnList) {
apnList.addPreference(preference);
}
for (Preference preference : mnoMmsApnList) {
apnList.addPreference(preference);
}
/// M: always set a prefer APN
setPreferApnChecked(mnoApnList);
/// M: update screen enable state according to airplane mode, SIM radio status, etc.
updateScreenEnableState(getActivity());
}
}
