net_serv.cc File Reference

#include <my_global.h>
#include <mysql.h>
#include <mysql_com.h>
#include <mysqld_error.h>
#include <my_sys.h>
#include <m_string.h>
#include <my_net.h>
#include <violite.h>
#include <signal.h>
#include <errno.h>
#include "probes_mysql.h"
#include <algorithm>

Defines
#define	update_statistics(A)
#define	thd_increment_bytes_sent(N)
#define	VIO_SOCKET_ERROR   ((size_t) -1)
#define	MAX_PACKET_LENGTH   (256L*256L*256L-1)
Functions
my_bool	my_net_init (NET *net, Vio *vio)
void	net_end (NET *net)
my_bool	net_realloc (NET *net, size_t length)
void	net_clear (NET *net, my_bool check_buffer __attribute__((unused)))
my_bool	net_flush (NET *net)
my_bool	my_net_write (NET *net, const uchar *packet, size_t len)
my_bool	net_write_command (NET *net, uchar command, const uchar *header, size_t head_len, const uchar *packet, size_t len)
my_bool	net_write_packet (NET *net, const uchar *packet, size_t length)
ulong	my_net_read (NET *net)
void	my_net_set_read_timeout (NET *net, uint timeout)
void	my_net_set_write_timeout (NET *net, uint timeout)

---

Detailed Description

This file is the net layer API for the MySQL client/server protocol.

Write and read of logical packets to/from socket.

Writes are cached into net_buffer_length big packets. Read packets are reallocated dynamicly when reading big packets. Each logical packet has the following pre-info: 3 byte length & 1 byte package-number.

This file needs to be written in C as it's used by the libmysql client as a C file.

---

Function Documentation

my_bool my_net_init	(	NET *	net,
		Vio *	vio
	)

Init with packet info.

ulong my_net_read

(

NET *

net

)

Read a packet from the client/server and return it without the internal package header.

If the packet is the first packet of a multi-packet packet (which is indicated by the length of the packet = 0xffffff) then all sub packets are read and concatenated.

If the packet was compressed, its uncompressed and the length of the uncompressed packet is returned.

Returns:

The function returns the length of the found packet or packet_error. net->read_pos points to the read data.

my_bool my_net_write	(	NET *	net,
		const uchar *	packet,
		size_t	len
	)

Write a logical packet with packet header.

Format: Packet length (3 bytes), packet number (1 byte) When compression is used, a 3 byte compression length is added.

Note:

If compression is used, the original packet is modified!

void net_clear	(	NET *	net,
		my_bool check_buffer	__attribute__(unused)
	)

Clear (reinitialize) the NET structure for a new command.

Remarks:

Performs debug checking of the socket buffer to ensure that the protocol sequence is correct.

Parameters:

net	NET handler
check_buffer	Whether to check the socket buffer.

my_bool net_flush

(

NET *

net

)

Flush write_buffer if not empty.

my_bool net_realloc	(	NET *	net,
		size_t	length
	)

Realloc the packet buffer.

my_bool net_write_command	(	NET *	net,
		uchar	command,
		const uchar *	header,
		size_t	head_len,
		const uchar *	packet,
		size_t	len
	)

Send a command to the server.

The reason for having both header and packet is so that libmysql can easy add a header to a special command (like prepared statements) without having to re-alloc the string.

As the command is part of the first data packet, we have to do some data juggling to put the command in there, without having to create a new packet.

This function will split big packets into sub-packets if needed. (Each sub packet can only be 2^24 bytes)

Parameters:

net	NET handler
command	Command in MySQL server (enum enum_server_command)
header	Header to write after command
head_len	Length of header
packet	Query or parameter to query
len	Length of packet

Return values:

0	ok
1	error

my_bool net_write_packet	(	NET *	net,
		const uchar *	packet,
		size_t	length
	)

Write a MySQL protocol packet to the network handler.

Parameters:

net	NET handler.
packet	The packet to write.
length	Length of the packet.

Remarks:

The packet might be encapsulated into a compressed packet.

Returns:

TRUE on error, FALSE on success.