HomeSpan/src/CallContext.cpp

146 lines
4.9 KiB
C++

/*********************************************************************************
* MIT License
*
* Copyright (c) 2020-2023 Michael Geramb
*
* https://github.com/HomeSpan/HomeSpan
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
********************************************************************************/
#include <Arduino.h>
#include "CallContext.h"
#include "HomeSpan.h"
#include "HAP.h"
#include "Settings.h"
#include <sodium.h>
CallContext::CallContext()
: stringBuffer(MINIMUM_STRING_BUFFER_SIZE, "CallContext stringBuffer")
{
}
void CallContext::printf(const char* format, ...)
{
va_list ap;
va_start(ap, format);
int len = vsnprintf(NULL, 0, format, ap);
char* buffer = reserveStringBuffer(len);
vsnprintf(buffer, len + 1, format, ap); // the reserved buffer is one byte larger because it contains the terminating '\0'
LOG2(buffer);
va_end(ap);
}
char* CallContext::reserveStringBuffer(int stringLength)
{
int requiredNewBufferLength = stringLength + 1; // reserve buffer for characters and string terminator '\0'
if (stringBuffer.len() - usedStringLength < requiredNewBufferLength)
{
// to less memory, send first exitsting buffer
if (usedStringLength > 0)
flush();
// Check if still more memory is needed
if (stringBuffer.len() < requiredNewBufferLength)
stringBuffer = TempBuffer<char>(requiredNewBufferLength, "SendEncryptedCallContext::reserveMemory");
}
int alreadyInUse = usedStringLength;
usedStringLength += stringLength;
char* result = stringBuffer.get() + alreadyInUse;
result[stringLength] = '\0'; // add string terminator
return result;
}
void CallContext::flush()
{
handlePage(stringBuffer.get(), usedStringLength);
usedStringLength = 0;
}
void CallContext::print(const char* text)
{
auto len = strlen(text);
auto buffer = reserveStringBuffer(len);
memcpy(buffer, text, len);
LOG2(buffer);
}
SendEncryptedCallContext::SendEncryptedCallContext(HAPClient& hapClient)
: hapClient(hapClient),
sendBuffer(FRAME_SIZE + 2 + 16, "SendEncryptedCallContext sendBuffer") // FRAME_SIZE + AAD + Auth
{
LOG2("\n>>>>>>>>>> ");
LOG2(hapClient.client.remoteIP());
LOG2(" >>>>>>>>>>\n");
}
void SendEncryptedCallContext::handlePage(const char* buffer, int length)
{
if (length == 0)
return;
LOG2(buffer);
for(int i=0;i<length;i+=FRAME_SIZE){ // encrypt FRAME_SIZE number of bytes in dataBuf in sequential frames
int n=length-i; // number of bytes remaining
if(n>FRAME_SIZE) // maximum number of bytes to encrypt=FRAME_SIZE
n=FRAME_SIZE;
sendBuffer.get()[0]=n%256; // store number of bytes that encrypts this frame (AAD bytes)
sendBuffer.get()[1]=n/256;
unsigned long long nBytes;
crypto_aead_chacha20poly1305_ietf_encrypt(sendBuffer.get()+2,&nBytes, (uint8_t*) buffer+i,n,sendBuffer.get(),2,NULL,hapClient.a2cNonce.get(),hapClient.a2cKey); // encrypt the next portion of dataBuf with authentication tag appended
hapClient.client.write(sendBuffer.get(),nBytes+2); // transmit encrypted frame
hapClient.a2cNonce.inc(); // increment nonce
}
}
SendEncryptedCallContext::~SendEncryptedCallContext()
{
flush();
LOG2("-------- SENT ENCRYPTED! --------\n");
}
CalcHashCallContext::CalcHashCallContext()
: CallContext()
{
memset(&tHash, 0, HASH_SIZE);
}
void CalcHashCallContext::handlePage(const char* buffer, int length)
{
uint8_t newHash[HASH_SIZE];
// create SHA-384 hash of JSON and xor with previous part (can be any hash - just looking for a unique key)
mbedtls_sha512_ret((uint8_t *)buffer,length, newHash,1);
for (int i=0; i<48; i++)
tHash[i] = tHash[i] ^ newHash[i];
}
const uint8_t* CalcHashCallContext::getHashCode()
{
flush();
return tHash;
}