vm.c File Reference

Implements a virtual machine for executing compiled intermediate language byte code. More...

Functions
err_t	calc (uint8_t *filter_code, int filter_len, uint8_t *packet_data, int packet_len, uint64_t *result_value, size_t *result_offset)
	Performs recursive execution of a subtree of the filter code. More...
bool	execute_filter (uint8_t *filter_code, int filter_len, uint8_t *packet_data, int packet_len, int *error_out)
	Executes the specified filter on the given packet. More...

Detailed Description

Implements a virtual machine for executing compiled intermediate language byte code.

Function Documentation

err_t calc	(	uint8_t *	filter_code,
		int	filter_len,
		uint8_t *	packet_data,
		int	packet_len,
		uint64_t *	result_value,
		size_t *	result_offset
	)

Performs recursive execution of a subtree of the filter code.

Parameters

	filter_code	Points to the begining of the filter code
	filter_len	Specifies the length of the filter code in bytes
	packet_data	Points to the packet data to run the filter on
	packet_len	Specifies the length of the packet data in bytes
[out]	result_value	Return value of the subtree execution
[in]	result_offset	Initially specifies the offset of the next byte to be executed in the filter code
[out]	result_offset	Specifies the next code byte to be executed, after the entire subtree code was executed

Returns

ERR_OK on success, other error values on failure; see header file for error types.

bool execute_filter	(	uint8_t *	filter_code,
		int	filter_len,
		uint8_t *	packet_data,
		int	packet_len,
		int *	error_out
	)

Executes the specified filter on the given packet.

Parameters

	filter_code	Points to the filters byte code
	filter_len	Length of the byte code
	packet_data	Points to the packet data to run the filter on
	packet_len	Length of packet data in bytes
[out]	error_out	Error information upon failure during execution

Returns

true, if the filter executed successfully and the result was not zero. false otherwise.