asdf

4 files changed, 150 insertions, 42 deletions

diff --git a/Makefile b/Makefile
index 13462bc..8b56258 100644
--- a/Makefile
+++ b/Makefile
@@ -30,8 +30,12 @@ $(OBJECTDIR)/%.o: $(SOURCEDIR)/%.c
 	@echo [CC] $<
 	@$(CC) $(CFLAGS) -c $< -o $@
 
-.PHONY: clean
+#sudo setcap 'cap_net_bind_service=+ep' /path/to/prog
+#to allow port access
+run: build
+	$(BUILDDIR)/$(OUTPUT)
 
+.PHONY: clean
 clean:
 	@echo [RM] $(OBJ)
 	@echo [RM] $(BUILDDIR)/$(OUTPUT)
diff --git a/src/dns.c b/src/dns.c
index 7c94c8a..2d3ac75 100644
--- a/src/dns.c
+++ b/src/dns.c
@@ -1,5 +1,36 @@
 #include "dns.h"
 
+int dns_parse_packet ( char* _buffer, int _bufflen, struct dns_message* _msg )
+{
+	if ( !_buffer || !_bufflen || !_msg )
+		return 1; //Invalid input
+
+	if ( _bufflen < 12 )
+		return 1; //Too short to contain a DNS header
+	
+	//TODO test
+	_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;
+	_msg->header.TC = (0x02 & *( (uint8_t*) (_buffer + 2))) >> 1;
+	_msg->header.RD = (0x01 & *( (uint8_t*) (_buffer + 2)));
+	_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.additional_count	= (*((uint8_t*) (_buffer + 10)) << 8) | *((uint8_t*) (_buffer + 11));
+
+	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;
+}
+
 int fqdn_to_qname( char* _source, int _sourcelen, char* _sink ,int _sinklen )
 {
 	int i;
diff --git a/src/dns.h b/src/dns.h
index 5d8096e..8cba804 100644
--- a/src/dns.h
+++ b/src/dns.h
@@ -2,6 +2,69 @@
 
 #include <stdint.h>
 
+//TODO remove
+#include <stdio.h>
+
+struct dns_header;
+
+struct dns_question;
+
+struct dns_answer;
+
+/**
+ * DNS Message struct
+ * */
+struct dns_message;
+
+struct dns_header {
+	uint16_t id;
+
+	uint8_t QR;	//Query:0 Reply:1
+	uint8_t OPCODE;	//Query:0 Iquery:1 Status:2
+	uint8_t AA;	//Authorative answer
+	uint8_t TC;	//Truncation
+	uint8_t RD;	//Recursion Desired
+	uint8_t RA;	//Recursion Available
+	uint8_t Z;	//Unused
+	uint8_t RCODE;	//Response Code
+
+	uint16_t question_count;
+	uint16_t answer_count;
+	uint16_t authorative_count;
+	uint16_t additional_count;
+};
+
+struct dns_question {
+	char* qname;
+	uint16_t qtype;
+	uint16_t qclass;
+};
+
+struct dns_answer {
+	char* name; //in qname format
+	uint16_t type;
+	uint16_t class;
+	uint32_t ttl;
+	uint16_t rdlength;
+	char* rdata;
+};
+
+struct dns_message {
+	struct dns_header header;
+	
+	int qcount;
+	struct dns_question* question;
+
+	int acount;
+	struct dns_answer* answer;
+};
+
+/**
+ * Parse the packet in _buffer and populate the dns_message struct
+ * returns: 0 on success, !=0 on failure
+ * */
+int dns_parse_packet ( char* _buffer, int _bufflen, struct dns_message* _msg );
+
 /**
  * Convert a null terminated string containing a 
  * fqdn (eg server.example.com) to the binary format used by DNS records
diff --git a/src/main.c b/src/main.c
index 9d3e214..92ca391 100644
--- a/src/main.c
+++ b/src/main.c
@@ -19,39 +19,21 @@
 
 #define UDP_BUFFER_LEN 512
 
-struct dns_message {
-	//Header
-	uint16_t id;
-
-	uint8_t QR;	//Query:0 Reply:1
-	uint8_t OPCODE;	//Query:0 Iquery:1 Status:2
-	uint8_t AA;	//Authorative answer
-	uint8_t TC;	//Truncation
-	uint8_t RD;	//Recursion Desired
-	uint8_t RA;	//Recursion Available
-	uint8_t RCODE;	//Response Code
-
-	uint16_t question_count;
-	uint16_t answer_count;
-	uint16_t authorative_count;
-	uint16_t additional_count;
-
-	//Question
-	//Answer
- };
-
+//main server socket
 int sock_server;
 
-int dns_parse_packet ( 	int _socket,
+int handle_connection (	int _socket,
 			struct sockaddr_in *sockaddr_client,
 			socklen_t sockaddr_client_len,
-			char* buffer,
-			int bufflen );
+			char* _buffer,
+			int _bufflen );
 
 void signal_term ( );
 
 void signal_term_child ( );
 
+void signal_child ( );
+
 int test_main(	int argc,
 		char* argv[] )
 {
@@ -60,7 +42,7 @@ int test_main(	int argc,
 	char in[128];
 	char out[128];
 
-	strncpy ( in, "aaa.aaaaa.aa\0", 127);
+	strncpy ( in, "sub.domain.example.com\0", 127);
 
 	printf("%s\n", in);
 
@@ -74,6 +56,15 @@ int test_main(	int argc,
 	for(int i = 0; i < written; i++)
 		printf(" %x ", out[i]);
 
+	written = qname_to_fqdn (out,128,in,128);
+	
+	if (written < 0) {
+		printf("invalid qname\n");
+		return 1;
+	}
+
+	printf("%s\n", in);
+
 	printf("\n\n");
 	return 0;
 }
@@ -89,11 +80,14 @@ int main(	int argc,
 	signal ( SIGTERM, signal_term );
 	signal ( SIGINT,  signal_term );
 
+	//Avoid zombie processes
+	signal (SIGCHLD, SIG_IGN);
+
 	log_init_stdout ( _LOG_DEBUG );
 
 	sock_server = socket ( AF_INET, SOCK_DGRAM, 0 );
 	if ( sock_server == -1 ) {
-		PRINT_ERRNO();
+		LOGPRINTF(_LOG_ERROR, "socket() failed");
 		return errno;
 	}
 
@@ -102,7 +96,7 @@ int main(	int argc,
 	sock_server_addr.sin_port   = htons( 53 );
 	ret = inet_aton ( "0.0.0.0", & sock_server_addr.sin_addr );
 	if( ret == 0 ) { //Error on 0, no errno!
-		LOGPRINTF(_LOG_NOTE, "inet_aton(): Invalid IP\n" );
+		LOGPRINTF(_LOG_NOTE, "inet_aton(): Invalid bind IP\n" );
 		return 1;
 	}
 
@@ -110,7 +104,7 @@ int main(	int argc,
 			(struct sockaddr*) &sock_server_addr,
 			sizeof(struct sockaddr_in) );
 	if ( ret == -1 ) {
-		PRINT_ERRNO();
+		LOGPRINTF(_LOG_ERROR, "bind() failed");
 		return errno;
 	}
 
@@ -118,6 +112,7 @@ int main(	int argc,
 	{
 		struct 		sockaddr_in sock_client_addr;
 		socklen_t	sock_client_addr_len;
+		pid_t pid;
 
 		sock_client_addr_len = sizeof ( struct sockaddr_in );
 		memset ( &sock_client_addr, '\0', sock_client_addr_len );
@@ -133,18 +128,18 @@ int main(	int argc,
 			return errno;
 		}
 
-		LOGPRINTF(_LOG_NOTE, "Connection");
+		LOGPRINTF(_LOG_DEBUG, "UDP Packet size %i", ret);
 
-		if ( dns_parse_packet ( sock_server,
+		if ( (pid = handle_connection (sock_server,
 					&sock_client_addr,
 					sock_client_addr_len,
 					recv_buffer,
-					ret ) ) {
-			LOGPRINTF(_LOG_ERROR, "dns_parse_packet()");
+					ret ) ) ) {
+			LOGPRINTF(_LOG_ERROR, "handle_connection() failed");
 			return errno;
 		}
 		else {
-			LOGPRINTF ( _LOG_DEBUG, "forked\n" );
+			LOGPRINTF ( _LOG_DEBUG, "forked " );
 		}
 	}
 
@@ -153,11 +148,11 @@ int main(	int argc,
 	return 0;
 }
 
-int dns_parse_packet (	int _socket,
+int handle_connection (	int _socket,
 			struct sockaddr_in *sockaddr_client,
 			socklen_t sockaddr_client_len,
-			char* buffer,
-			int bufflen )
+			char* _buffer,
+			int _bufflen )
 {
 	pid_t pid = fork();
 	
@@ -165,13 +160,27 @@ int dns_parse_packet (	int _socket,
 		return 0;
 	else if ( pid < 0 )
 		return errno;
+	
+	//Change signal handler. signal_term shuts down entire socket on TERM
+	signal ( SIGTERM, signal_term_child );
 
-	signal ( SIGTERM, signal_term_child);
+	//echo request
+	sendto (_socket, _buffer, _bufflen, 0, (struct sockaddr*) sockaddr_client, sockaddr_client_len);
 
-	struct dns_message msg;
+	//Testing recieved question
+	//TODO remove
+	char out[128];
+	qname_to_fqdn((_buffer+12), _bufflen-12, out, 128);
+	printf("%s\n", out);
 
-	msg.id = *( (uint16_t*) buffer );
-	msg.QR =  0x80 & *( (uint8_t*) (buffer + 2));
+	
+	struct dns_message msg;
+	
+	if (dns_parse_packet (_buffer, _bufflen, &msg) ) {
+		LOGPRINTF (_LOG_DEBUG, "Malformed packet recieved. parsing failed");
+		close ( _socket );
+		exit( 1 );
+	}
 
 	exit ( 0 );
 }
@@ -179,7 +188,8 @@ int dns_parse_packet (	int _socket,
 void signal_term ( ) {
 	printf( "Recieved Signal. Terminating active connections and closing socket\n" );
 	
-	kill ( 0, SIGTERM ); //terminate all child processes
+	//terminate all children >:)
+	kill ( 0, SIGTERM ); 
 
 	shutdown ( sock_server, SHUT_RDWR );
 	close ( sock_server );