Traffic Control

Collaboration diagram for Traffic Control:

Modules
	Queueing Classes
	Classifiers
	Queueing Disciplines

Macros
#define	RTNL_TC_RTABLE_SIZE   256
	Number of entries in a transmission time lookup table. More...

Enumerations
enum	rtnl_tc_stats_id {   RTNL_TC_PACKETS,   RTNL_TC_BYTES,   RTNL_TC_RATE_BPS,   RTNL_TC_RATE_PPS,   RTNL_TC_QLEN,   RTNL_TC_BACKLOG,   RTNL_TC_DROPS,   RTNL_TC_REQUEUES,   RTNL_TC_OVERLIMITS,   __RTNL_TC_STATS_MAX }
	TC statistics identifiers. More...

Utilities
int	rtnl_tc_calc_txtime (int bufsize, int rate)
	Calculate time required to transmit buffer at a specific rate. More...
int	rtnl_tc_calc_bufsize (int txtime, int rate)
	Calculate buffer size able to transmit in a specific time and rate. More...
int	rtnl_tc_calc_cell_log (int cell_size)
	Calculate the binary logarithm for a specific cell size. More...

Rate Tables
int	rtnl_tc_build_rate_table (uint32_t *dst, uint8_t mpu, uint8_t overhead, int cell, int rate)
	Compute a transmission time lookup table. More...

Traffic Control Handle Translations
char *	rtnl_tc_handle2str (uint32_t handle, char *buf, size_t len)
	Convert a traffic control handle to a character string (Reentrant). More...
int	rtnl_tc_str2handle (const char *name, uint32_t *res)
	Convert a charactering strint to a traffic control handle. More...

Detailed Description

Macro Definition Documentation

#define RTNL_TC_RTABLE_SIZE   256

Number of entries in a transmission time lookup table.

Referenced by rtnl_tc_build_rate_table().

Enumeration Type Documentation

enum rtnl_tc_stats_id

TC statistics identifiers.

Enumerator
RTNL_TC_PACKETS	Packets seen.
RTNL_TC_BYTES	Bytes seen.
RTNL_TC_RATE_BPS	Current bits/s (rate estimator)
RTNL_TC_RATE_PPS	Current packet/s (rate estimator)
RTNL_TC_QLEN	Queue length.
RTNL_TC_BACKLOG	Backlog length.
RTNL_TC_DROPS	Packets dropped.
RTNL_TC_REQUEUES	Number of requeues.
RTNL_TC_OVERLIMITS	Number of overlimits.
__RTNL_TC_STATS_MAX

Function Documentation

int rtnl_tc_build_rate_table	(	uint32_t *	dst,
		uint8_t	mpu,
		uint8_t	overhead,
		int	cell,
		int	rate
	)

Compute a transmission time lookup table.

• dst Destination buffer of RTNL_TC_RTABLE_SIZE uint32_t[].
• mpu Minimal size of a packet at all times.
• overhead Overhead to be added to each packet.
• cell Size of cell, i.e. size of step between entries in bytes.
• rate Rate in bytes per second.

Computes a table of RTNL_TC_RTABLE_SIZE entries specyfing the transmission times for various packet sizes, e.g. the transmission time for a packet of size pktsize could be looked up:

txtime = table[pktsize >> log2(cell)];

References rtnl_tc_calc_cell_log(), rtnl_tc_calc_txtime(), RTNL_TC_RTABLE_SIZE, and size.

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int rtnl_tc_calc_bufsize	(	int	txtime,
		int	rate
	)

Calculate buffer size able to transmit in a specific time and rate.

• txtime Available transmit time in micro seconds.
• rate Transmit rate in bytes per second.

Calculates the size of the buffer that can be transmitted in a specific time period at a specific transmit rate.

Returns

Size of buffer in bytes.

int rtnl_tc_calc_cell_log

(

int

cell_size

)

Calculate the binary logarithm for a specific cell size.

• cell_size Size of cell, must be a power of two.

  Returns

  Binary logirhtm of cell size or a negative error code.

References NLE_INVAL.

Referenced by rtnl_tc_build_rate_table().

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int rtnl_tc_calc_txtime	(	int	bufsize,
		int	rate
	)

Calculate time required to transmit buffer at a specific rate.

• bufsize Size of buffer to be transmited in bytes.
• rate Transmit rate in bytes per second.

Calculates the number of micro seconds required to transmit a specific buffer at a specific transmit rate.

Returns

Required transmit time in micro seconds.

Referenced by rtnl_qdisc_tbf_set_peakrate(), rtnl_qdisc_tbf_set_rate(), and rtnl_tc_build_rate_table().

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char* rtnl_tc_handle2str	(	uint32_t	handle,
		char *	buf,
		size_t	len
	)

Convert a traffic control handle to a character string (Reentrant).

• handle traffic control handle
• buf destination buffer
• len buffer length

Converts a tarffic control handle to a character string in the form of MAJ:MIN and stores it in the specified destination buffer.

Returns

The destination buffer or the type encoded in hexidecimal form if no match was found.

References buf, TC_H_MAJ, TC_H_MIN, TC_H_ROOT, and TC_H_UNSPEC.

int rtnl_tc_str2handle	(	const char *	name,
		uint32_t *	res
	)

Convert a charactering strint to a traffic control handle.

• name traffic control handle as character string
• res destination buffer

Converts the provided character string specifying a traffic control handle to the corresponding numeric value.

The handle must be provided in one of the following formats:

• root
• none
• XXXX:
• :YYYY
• XXXX:YYYY
• XXXXYYYY

Returns

0 on success or a negative error code

References NLE_INVAL, NLE_RANGE, TC_H_MAJ, TC_H_ROOT, and TC_H_UNSPEC.

Referenced by main(), nl_cli_qdisc_parse_handle(), nl_cli_qdisc_parse_parent(), parse_handle(), and parse_parent().

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