add: Implement record parsing

[cassiopeia.git] / src / record.cpp

diff --git a/src/record.cpp b/src/record.cpp
new file mode 100644 (file)
index 0000000..5993b60
--- /dev/null
+++ b/src/record.cpp
@@ -0,0 +1,112 @@
+#include "record.h"
+
+#include <iomanip>
+#include <iostream>
+#include <memory>
+#include <sstream>
+
+#include "bios.h"
+#include "opensslBIO.h"
+
+std::string toHexAndChecksum( const std::string& src ) {
+    char checksum = 0;
+    std::stringstream ss;
+    ss << ':' << std::hex << std::setfill( '0' ) << std::uppercase;
+
+    for( auto c : src ) {
+        ss << std::setw( 2 ) << ( ( ( uint32_t ) c ) & 0xFF );
+        checksum += c;
+    }
+
+    ss << std::setw( 2 ) << ( ( ( uint32_t )( ~checksum ) ) & 0xFF );
+    ss << '\n';
+    return ss.str();
+}
+
+void sendCommand( RecordHeader& head, const std::string& data, std::shared_ptr<OpensslBIO> bio ) {
+    head.payloadLength = data.size();
+    std::string s;
+    s += head.packToString();
+    s += data;
+
+    std::string res = toHexAndChecksum( s );
+    bio->write( res.data(), res.size() );
+}
+
+int32_t fromHexDigit( char c ) {
+    int32_t res = -1;
+
+    if( c >= '0' && c <= '9' ) {
+        res = c - '0';
+    }
+
+    if( c >= 'A' && c <= 'F' ) {
+        res = c - 'A' + 10;
+    }
+
+    return res;
+}
+
+std::string parseCommand( RecordHeader& head, const std::string& input ) {
+    int32_t dlen = ( input.size() - 2 ) / 2;
+    char checksum = 0;
+    bool error = false;
+
+    std::string str( std::max( dlen, RECORD_HEADER_SIZE ), 0 );
+    str.append( 0, dlen );
+
+    for( int i = 0; i < dlen; i++ ) {
+        int32_t digit;
+        int32_t accum;
+        digit = fromHexDigit( input[i * 2 + 1] );
+        error |= digit == -1;
+        accum = digit;
+        accum <<= 4;
+        digit = fromHexDigit( input[i * 2 + 2] );
+        error |= digit == -1;
+        accum += digit;
+        str[i] = accum;
+        checksum += str[i];
+    }
+
+    head.unpackFromString( str.substr( 0, RECORD_HEADER_SIZE ) );
+    uint32_t len = head.payloadLength;
+    uint32_t expectedTotalLength = ( RECORD_HEADER_SIZE + len + 1 /*checksum*/ ) * 2 + 2;
+    std::string data = str.substr( RECORD_HEADER_SIZE, str.size() - RECORD_HEADER_SIZE );
+
+    if( checksum != -1 || expectedTotalLength != input.size() || error || dlen < RECORD_HEADER_SIZE ) {
+        throw "Error, invalid checksum";
+    }
+
+    data.pop_back();
+
+    return data;
+}
+
+/*
+int main( int argc, char* argv[] ) {
+    OpensslBIOWrapper *bio = new OpensslBIOWrapper(BIO_new_fd(0, 0));
+    std::string data = "halloPayload";
+    RecordHeader head;
+    head.command = 0x7;
+    head.flags = 1;
+    head.sessid = 13;
+    head.command_count = 0xA0B;
+    head.totalLength = 9;
+    sendCommand( head, data, std::shared_ptr<OpensslBIO>(bio) );
+    head.command = 0x8;
+
+    try {
+        std::string c = parseCommand( head, ":0700010D0000000B0A0900000000000C0068616C6C6F5061796C6F6164E6\n" );
+
+        std::cout << "res: " << std::endl;
+        std::cout << head.payloadLength << std::endl;
+        std::cout << c << std::endl;
+    } catch( char const* c ) {
+        std::cout << "err: " << c << std::endl;
+    }
+
+
+    return 0;
+}
+*/