src/java/iotcloud/CloudComm.java

   1 package iotcloud;
   2 import java.io.*;
   3 import java.net.*;
   4 import java.util.Arrays;
   5 import javax.crypto.*;
   6 import javax.crypto.spec.*;
   7 import java.security.SecureRandom;
   8
   9 class CloudComm {
  10         String baseurl;
  11         Cipher encryptcipher;
  12         Cipher decryptcipher;
  13         Mac mac;
  14         byte[] salt;
  15         SecretKeySpec key;
  16         static final int SALT_SIZE = 8;
  17
  18
  19         CloudComm() {
  20         }
  21
  22         CloudComm(String _baseurl, String password) {
  23                 this.baseurl=_baseurl;
  24                 initCloud(password);
  25         }
  26
  27         private void initKey(String password) {
  28                 try {
  29                         salt=new byte[SALT_SIZE];
  30                         SecureRandom random = new SecureRandom();
  31                         random.nextBytes(salt);
  32                         PBEKeySpec keyspec = new PBEKeySpec(password.toCharArray(), salt, 65536, 128);
  33                         SecretKey tmpkey = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256").generateSecret(keyspec);
  34                         this.key = new SecretKeySpec(tmpkey.getEncoded(), "AES");
  35                 } catch (Exception e) {
  36                         e.printStackTrace();
  37                         throw new Error("Failed generating key.");
  38                 }
  39         }
  40
  41         private void initCloud(String password) {
  42                 try {
  43                         initKey(password);
  44                         mac = Mac.getInstance("HmacSHA256");
  45                         mac.init(key);
  46                 } catch (Exception e) {
  47                         e.printStackTrace();
  48                         throw new Error("Failed To Initialize Ciphers");
  49                 }
  50         }
  51
  52         private URL buildRequest(boolean isput, long sequencenumber, long maxentries) throws IOException {
  53                 String reqstring=isput?"req=putslot":"req=getslot";
  54                 String urlstr=baseurl+"?"+reqstring+"&seq="+sequencenumber;
  55                 if (maxentries != 0)
  56                         urlstr += "&max="+maxentries;
  57                 return new URL(urlstr);
  58         }
  59
  60         public Slot[] putSlot(Slot slot, int max) {
  61                 try {
  62                         long sequencenumber=slot.getSequenceNumber();
  63                         byte[] bytes=slot.encode(mac);
  64
  65                         URL url=buildRequest(true, sequencenumber, max);
  66                         URLConnection con=url.openConnection();
  67                         HttpURLConnection http = (HttpURLConnection) con;
  68                         http.setRequestMethod("POST");
  69                         http.setFixedLengthStreamingMode(bytes.length + SALT_SIZE);
  70                         http.setDoOutput(true);
  71                         http.connect();
  72                         OutputStream os=http.getOutputStream();
  73                         os.write(salt);
  74                         os.write(bytes);
  75                         System.out.println(http.getResponseMessage());
  76
  77                         InputStream is=http.getInputStream();
  78                         DataInputStream dis=new DataInputStream(is);
  79                         byte[] resptype=new byte[7];
  80                         dis.readFully(resptype);
  81                         if (Arrays.equals(resptype, "getslot".getBytes()))
  82                                 return processSlots(dis);
  83                         else if (Arrays.equals(resptype, "putslot".getBytes()))
  84                                 return null;
  85                         else
  86                                 throw new Error("Bad response to putslot");
  87                 } catch (Exception e) {
  88                         throw new Error("putSlot failed");
  89                 }
  90         }
  91
  92         /*
  93                         Cipher encryptCipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
  94                         encryptCipher.init(Cipher.ENCRYPT_MODE, secret);
  95                         Cipher decryptCipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
  96                         decryptCipher.init(Cipher.DECRYPT_MODE, secret);
  97         */
  98
  99         public Slot[] getSlots(long sequencenumber) {
 100                 try {
 101                         URL url=buildRequest(false, sequencenumber, 0);
 102                         URLConnection con=url.openConnection();
 103                         HttpURLConnection http = (HttpURLConnection) con;
 104                         http.setRequestMethod("POST");
 105                         http.connect();
 106                         System.out.println(http.getResponseMessage());
 107                         InputStream is=http.getInputStream();
 108
 109                         DataInputStream dis=new DataInputStream(is);
 110                         byte[] resptype=new byte[7];
 111                         dis.readFully(resptype);
 112                         if (!Arrays.equals(resptype, "getslot".getBytes()))
 113                                 throw new Error("Bad Response: "+new String(resptype));
 114                         else
 115                                 return processSlots(dis);
 116                 } catch (Exception e) {
 117                         throw new Error("getSlots failed");
 118                 }
 119         }
 120
 121         Slot[] processSlots(DataInputStream dis) throws IOException {
 122                 int numberofslots=dis.readInt();
 123                 int[] sizesofslots=new int[numberofslots];
 124                 Slot[] slots=new Slot[numberofslots];
 125                 for(int i=0; i<numberofslots; i++)
 126                         sizesofslots[i]=dis.readInt();
 127
 128                 for(int i=0; i<numberofslots; i++) {
 129                         byte[] data=new byte[sizesofslots[i]];
 130                         dis.readFully(data);
 131                         slots[i]=Slot.decode(data, mac);
 132                 }
 133                 dis.close();
 134                 return slots;
 135         }
 136 }