短信发送流程图形剖析（含编码）Android平台

Android平台 短信发送流程图形剖析(含编码)

转自：http://lzd20021683.iteye.com/blog/1306918

其他SMS/MMS分析：http://lzd20021683.iteye.com/category/187047

本文对Android平台短信发送流程进行了走读和剖析，特别是编码部分，今天将流程整理出来，以便平时参考，也希望对大家有用！！！

先上图，下面2个图是用PPT画的，这里截图附上来：

流程图1：

Framewoks

流程图2：

发送流程编码解析：

从上图中的GsmSMSDispatcher的sendText开始分析

Java代码 1. //GsmSMSDispatcher.java 2. /** {@inheritDoc} */ 3. @Override 4. // ①入口

5. protected void sendText(String destAddr, String scAddr, String text, 6. PendingIntent sentIntent, PendingIntent deliveryIntent) { 7. SmsMessage.SubmitPdu pdu = SmsMessage.getSubmitPdu ( //转②分析 8. scAddr, destAddr, text, (deliveryIntent != null));

9. 10. HashMap map = SmsTrackerMapFactory(destAddr, scAddr, text, pdu); 11. SmsTracker tracker = SmsTrackerFactory(map, sentIntent, deliveryIntent, 12. RadioTechnologyFamily.RADIO_TECH_3GPP); 13. sendRawPdu(tracker); //转I分析

14. }

15. 16. ②分析：

17. //SmsMessage.java

18. public static SubmitPdu getSubmitPdu(String scAddress, 19. String destinationAddress, String message, 20. boolean statusReportRequested) {

21. return getSubmitPdu(scAddress, destinationAddress, message, statusReportRequested, null); //转③分

析 22. }

23. 24. ③分析

25. //SmsMessage.java

26. public static SubmitPdu getSubmitPdu(String scAddress, 27. String destinationAddress, String message, 28. boolean statusReportRequested, byte[] header) {

29. return getSubmitPdu(scAddress, destinationAddress, message, statusReportRequested, header,ENCODIN

G_UNKNOWN/*默认编码方式*/); //转④分析 30. }

31. 32. ④分析 编码核心函数

33. //SmsMessage.java

34. public static SubmitPdu getSubmitPdu(String scAddress, 35. String destinationAddress, String message,

36. boolean statusReportRequested, byte[] header, int encoding) { 37. // 3

38. // Perform null parameter checks.

39. if (message == null || destinationAddress == null) { 40. return null; 41. }

42. 43. SubmitPdu ret = new SubmitPdu(); 44. // MTI = SMS-SUBMIT, UDHI = header != null 45. byte mtiByte = (byte)(0x01 | (header != null ? 0x40 : 0x00));

46. //MTI :bit 0 和 bit1 UDHI：bit6

47. // 0x01 = 0000 0001 0x40 = 0010 0000 48. ByteArrayOutputStream bo = getSubmitPduHead( 49. scAddress, destinationAddress, mtiByte, 50. statusReportRequested, ret); //转⑤分析 51. // User Data (and length) //TP-DCS 和TP-UDL 52. byte[] userData;

53. if (encoding == ENCODING_UNKNOWN) {

54. // First, try encoding it with the GSM alphabet

55. encoding = ENCODING_7BIT; //默认先采用ENCODING_7BIT编码模式 56. } 57. try {

58. if (encoding == ENCODING_7BIT) {

59. userData = GsmAlphabet.stringToGsm7BitPackedWithHeader(message, header);

60. //采用ENCODING_7BIT进行编码，若出现编码异常，函数会抛出异常：EncodeException，转至⑥处。编码成功转

至⑦。stringToGsm7BitPackedWithHeader分析转⑧处 61. } else { //assume UCS-2 62. try {

63. userData = encodeUCS2(message, header); 64. } catch(UnsupportedEncodingException uex) { 65. Log.e(LOG_TAG,

66. \, 67. uex); 68. return null; 69. } 70. }

71. } catch (EncodeException ex) { //⑥ 7bit编码模式失败后，就采用UCS-2进行编码 72. // Encoding to the 7-bit alphabet failed. Let's see if we can 73. // send it as a UCS-2 encoded message 74. try {

75. userData = encodeUCS2(message, header); 76. encoding = ENCODING_16BIT;

77. } catch(UnsupportedEncodingException uex) { 78. Log.e(LOG_TAG,

79. \, 80. uex); 81. return null; 82. } 83. }

84. 85. if (encoding == ENCODING_7BIT) { //⑦ 7bit编码成功 86. if ((0xff & userData[0]) > MAX_USER_DATA_SEPTETS) { 87. // Message too long 88. return null; 89. } 90. // TP-Data-Coding-Scheme 91. // Default encoding, uncompressed 92. // To test writing messages to the SIM card, change this value 0x00 93. // to 0x12, which means \ 94. // class is 2\ 95. // words, messages sent by the phone with this change will end up on 96. // the receiver's SIM card. You can then send messages to yourself 97. // (on a phone with this change) and they'll end up on the SIM card.

98. //0x12 = 0001 0010 未压缩，class2，存储到SIM卡 99. //0x00 = 0000 0000 未压缩，class0，GSM7bit编码 100. bo.write(0x00); 101. } else { // assume UCS-2

102. if ((0xff & userData[0]) > MAX_USER_DATA_BYTES) { 103. // Message too long 104. return null; 105. }

106. // TP-Data-Coding-Scheme

107. // Class 3, UCS-2 encoding, uncompressed

108. bo.write(0x0b); //0x0b = 0000 1011 未压缩，class3，UCS-2编码 109. }

110.

111. // (no TP-Validity-Period)

112. bo.write(userData, 0, userData.length); 113. ret.encodedMessage = bo.toByteArray(); 114. return ret; 115. } 116. 117. ⑤分析

118. //SmsMessage.java

119. private static ByteArrayOutputStream getSubmitPduHead(

120. String scAddress, String destinationAddress, byte mtiByte, 121. boolean statusReportRequested, SubmitPdu ret) 122. //scAddress为短信中心号码，destinationAddress为目标地址号码

123. //mtiByte为MTI和UDHI 编码数据，见上面分析，statusReportRequested为状态报告 //ret 下面会写入数据

到ret 124. {

125. ByteArrayOutputStream bo = new ByteArrayOutputStream( 126. MAX_USER_DATA_BYTES + 40);

127.

128. // SMSC address with length octet, or 0 129. if (scAddress == null) {

130. ret.encodedScAddress = null; 131. } else {

132. ret.encodedScAddress = PhoneNumberUtils.networkPortionToCalledPartyBCDWithLength(

133. scAddress); 134. }

135. // TP-Message-Type-Indicator (and friends) 136. if (statusReportRequested) {

137. // Set TP-Status-Report-Request bit. //TP-SRR bit 5 ,0x20 = 0010 0000 138. mtiByte |= 0x20;

139. if (Config.LOGD) Log.d(LOG_TAG, \); 140. }

141. bo.write(mtiByte);

142.

143. // space for TP-Message-Reference //TP-MR 144. bo.write(0); 145.

146. byte[] daBytes; 147.

148. daBytes = PhoneNumberUtils.networkPortionToCalledPartyBCD(destinationAddress); 149.

150. // destination address length in BCD digits, ignoring TON byte and pad

151. // TODO Should be better. 152. bo.write((daBytes.length - 1) * 2

153. - ((daBytes[daBytes.length - 1] & 0xf0) == 0xf0 ? 1 : 0));

154.

155. // destination address

156. bo.write(daBytes, 0, daBytes.length); 157.

158. // TP-Protocol-Identifier //TP--PID 159. bo.write(0); 160. return bo; 161. } 162. 163. ⑧分析

164. //GsmAlphabet.java

165. public static byte[] stringToGsm7BitPackedWithHeader(String data, byte[] header) 166. throws EncodeException { //这里传进来的head为null

167.

168. if (header == null || header.length == 0) {

169. return stringToGsm7BitPacked(data); //转⑨分析 170. } 171.

172. int headerBits = (header.length + 1) * 8; 173. int headerSeptets = (headerBits + 6) / 7; 174.

175. byte[] ret = stringToGsm7BitPacked(data, headerSeptets, true); 176.

177. // Paste in the header

178. ret[1] = (byte)header.length;

179. System.arraycopy(header, 0, ret, 2, header.length); 180. return ret; 181. } 182. 183. ⑨分析

184. //GsmAlphabet.java

185. public static byte[] stringToGsm7BitPacked(String data) 186. throws EncodeException {

187. return stringToGsm7BitPacked(data, 0, true); //转⑩分析 188. }

189. 190. ⑩分析

191. //GsmAlphabet.java

192. public static byte[] stringToGsm7BitPacked(String data, int startingSeptetOffset, 193. boolean throwException) throws EncodeException { 194. int dataLen = data.length();

195. int septetCount = countGsmSeptets(data, throwException) + startingSeptetOffset; 196. // 当传入的字符串data中含有charToGsm, charToGsmExtended中没有的字符时(例如汉字)，该函数会抛出异

常，这样在调用处⑥会捕获该异常。然后会采用UCS-2方式进行编码。

197.

198. if (septetCount > 255) {

199. throw new EncodeException(\); 200. }

201. int byteCount = ((septetCount * 7) + 7) / 8;

202. byte[] ret = new byte[byteCount + 1]; // Include space for one byte length prefix. 203. for (int i = 0, septets = startingSeptetOffset, bitOffset = startingSeptetOffset * 7; 204. i < dataLen && septets < septetCount; 205. i++, bitOffset += 7) { 206. char c = data.charAt(i);

207. int v = GsmAlphabet.charToGsm(c, throwException); 208. if (v == GSM_EXTENDED_ESCAPE) {

209. v = GsmAlphabet.charToGsmExtended(c); // Lookup the extended char. 210. packSmsChar(ret, bitOffset, GSM_EXTENDED_ESCAPE); 211. bitOffset += 7; 212. septets++; 213. }

214. packSmsChar(ret, bitOffset, v); 215. septets++; 216. }

217. ret[0] = (byte) (septetCount); // Validated by check above. 218. return ret;

219. }

220.

221. I分析:

222. //SMSDispatcher.java

223. protected void sendRawPdu(SmsTracker tracker) { 224. HashMap map = tracker.mData;

225. byte pdu[] = (byte[]) map.get(\);

226.

227. PendingIntent sentIntent = tracker.mSentIntent; 228. if (mSmsSendDisabled) {

229. if (sentIntent != null) { 230. try {

231. sentIntent.send(RESULT_ERROR_NO_SERVICE); 232. } catch (CanceledException ex) {} 233. }

234. Log.d(TAG, \); 235. return; 236. } 237.

238. if (pdu == null) {

239. if (sentIntent != null) { 240. try {

241. sentIntent.send(RESULT_ERROR_NULL_PDU); 242. } catch (CanceledException ex) {} 243. }

244. return; 245. }

246.

247. int ss = mPhone.getServiceState().getState(); 248.

249. // if IMS not registered on data and voice is not available... 250. if (!isIms() && ss != ServiceState.STATE_IN_SERVICE) { 251. handleNotInService(ss, tracker); 252. } else {

253. String appName = getAppNameByIntent(sentIntent); 254. if (mCounter.check(appName, SINGLE_PART_SMS)) { 255. sendSms(tracker); // 转II分析 256. } else {

257. sendMessage(obtainMessage(EVENT_POST_ALERT, tracker)); 258. } 259. } 260. } 261.

262. II分析:

263. //GsmSMSDispatcher.java 264. /** {@inheritDoc} */ 265. @Override

266. protected void sendSms(SmsTracker tracker) { 267. HashMap map = tracker.mData;

268.

269. byte smsc[] = (byte[]) map.get(\); 270. byte pdu[] = (byte[]) map.get(\); 271.

272. Message reply = obtainMessage(EVENT_SEND_SMS_COMPLETE, tracker); 273.

274. if (tracker.mRetryCount > 0 || !isIms()) { 275. // this is retry, use old method

276. mCm.sendSMS(IccUtils.bytesToHexString(smsc),

277. IccUtils.bytesToHexString(pdu), reply); 278. } else {

279. mCm.sendImsGsmSms(IccUtils.bytesToHexString(smsc), 280. IccUtils.bytesToHexString(pdu), reply); 281. } 282. }

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