Parser seems working for requests

1 files changed, 54 insertions, 10 deletions

diff --git a/src/dns.c b/src/dns.c
index 2d3ac75..eaa032e 100644
--- a/src/dns.c
+++ b/src/dns.c
@@ -7,9 +7,9 @@ int dns_parse_packet ( char* _buffer, int _bufflen, struct dns_message* _msg )
 
 	if ( _bufflen < 12 )
 		return 1; //Too short to contain a DNS header
-	
+
 	//TODO test
-	_msg->header.id = *( (uint16_t*) _buffer );	
+	_msg->header.id = *( (uint16_t*) _buffer );
 	_msg->header.QR =  ( 0x80 & *( (uint8_t*) (_buffer + 2)) ) >> 7;
 	_msg->header.OPCODE = (0x78 & *( (uint8_t*) (_buffer + 2))) >> 3;
 	_msg->header.AA = (0x04 & *( (uint8_t*) (_buffer + 2))) >> 2;
@@ -18,17 +18,41 @@ int dns_parse_packet ( char* _buffer, int _bufflen, struct dns_message* _msg )
 	_msg->header.RA = (0x80 & *( (uint8_t*) (_buffer + 3))) >> 7;
 	_msg->header.Z  = (0x70 & *( (uint8_t*) (_buffer + 3))) >> 4;
 	_msg->header.RCODE = (0x0F & *( (uint8_t*) (_buffer + 3)));
-	_msg->header.question_count	= (*((uint8_t*) (_buffer + 4)) << 8) | *((uint8_t*) (_buffer + 5));
-	_msg->header.answer_count	= (*((uint8_t*) (_buffer + 6)) << 8) | *((uint8_t*) (_buffer + 7));
-	_msg->header.authorative_count	= (*((uint8_t*) (_buffer + 8)) << 8) | *((uint8_t*) (_buffer + 9));
+	_msg->header.question_count	= (*((uint8_t*) (_buffer + 4 )) << 8) | *((uint8_t*) (_buffer + 5 ));
+	_msg->header.answer_count	= (*((uint8_t*) (_buffer + 6 )) << 8) | *((uint8_t*) (_buffer + 7 ));
+	_msg->header.authorative_count	= (*((uint8_t*) (_buffer + 8 )) << 8) | *((uint8_t*) (_buffer + 9 ));
 	_msg->header.additional_count	= (*((uint8_t*) (_buffer + 10)) << 8) | *((uint8_t*) (_buffer + 11));
-
+	//TODO remove
 	printf("ANSWER %i\n", _msg->header.answer_count);
 	printf("QUESTI %i\n", _msg->header.question_count);
 	printf("AUTHOR %i\n", _msg->header.authorative_count);
 	printf("ADDITI %i\n", _msg->header.additional_count);
-	
-	return 1;
+
+	//Allocate question array
+	//TODO Only implements question section.
+	size_t qsize = sizeof(typeof(*(_msg->question))) * _msg->question_count;
+	_msg->question_count = _msg->header.question_count;
+	_msg->question = malloc ( qsize );
+	memset( _msg->question, 0, qsize );
+
+	int ptr = 12; //byte counter
+	for (int i = 0; i < _msg->question_count; i++) {
+		int qname_len = qname_check ( (_buffer + ptr), _bufflen - ptr);
+
+		if (qname_len <= 0) //Check for faulty QNAME
+			return 1;
+
+		_msg->question[i].qname = _buffer + ptr;
+		ptr += qname_len;
+		_msg->question[i].qtype = (uint16_t*) (_buffer + ptr);
+		ptr += 2;
+		_msg->question[i].qclass = (uint16_t*) (_buffer + ptr);
+
+		if( ptr >= _bufflen ) //Out of bounds check
+			return 1;
+	}
+
+	return 0;
 }
 
 int fqdn_to_qname( char* _source, int _sourcelen, char* _sink ,int _sinklen )
@@ -60,7 +84,7 @@ int fqdn_to_qname( char* _source, int _sourcelen, char* _sink ,int _sinklen )
 	_sink[lastdot] = i - lastdot;
 	_sink[i + 1] = 0;
 
-	return i+2; 
+	return i+2;
 }
 
 
@@ -85,8 +109,28 @@ int qname_to_fqdn( char* _source, int _sourcelen, char* _sink, int _sinklen )
 		} else {
 			_sink[i-1] = _source[i];
 		}
+	}
+	return i-1;
+}
+
+int qname_check( char* _source, int _sourcelen )
+{
+	if (!_sourcelen)
+		return -1;
 
+	int next_dot = 0;
+
+	for (int i = 0; i < _sourcelen; i++) {
+		if ( i == next_dot ) {
+			if (_source[i]) { //Not last dot
+				next_dot = _source[i] + i + 1;
+			} else { //last dot
+				return i+1;
+			}
+		} else if (!_source[i]) { //Invalid qname
+			return -1;
+		}
 	}
 
-	return i-1;
+	return -1;
 }