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

#include <string.h>
#include <sys/types.h>
#include <algorithm>
#include <mysql/components/services/log_builtins.h>
#include <mysql/thread_pool_priv.h>
#include "../sql/current_thd.h"
#include "../sql/sql_class.h"
#include "../sql/sql_thd_internal_api.h"
#include "my_byteorder.h"
#include "my_compiler.h"
#include "my_dbug.h"
#include "my_io.h"
#include "my_macros.h"
#include "my_sys.h"
#include "mysql.h"
#include "mysql/service_mysql_alloc.h"
#include "mysql_async.h"
#include "mysql_com.h"
#include "mysqld_error.h"
#include "violite.h"
#include "sql/psi_memory_key.h"
#include "mysql_com_server.h"

Functions
void	thd_increment_bytes_sent (size_t length)

void	thd_increment_bytes_received (size_t length)

static bool	net_write_buff (NET net, const uchar packet, size_t len)
	Caching the data in a local buffer before sending it. More...

static uchar *	compress_packet (NET net, const uchar packet, size_t *length)
	Compress and encapsulate a packet into a compressed packet. More...

NET_EXTENSION *	net_extension_init ()

void	net_extension_free (NET *net)

static mysql_compress_context *	compress_context (NET *net)
	Returns the appropriate compression_context based on caller. More...

bool	my_net_init (NET net, Vio vio)
	Init with packet info. More...

void	net_end (NET *net)

void	net_claim_memory_ownership (NET *net, bool claim)

bool	net_realloc (NET *net, size_t length)
	Realloc the packet buffer. More...

void	net_clear (NET *net, bool check_buffer)
	Clear (reinitialize) the NET structure for a new command. More...

bool	net_flush (NET *net)
	Flush write_buffer if not empty. More...

static bool	net_should_retry (NET net, uint retry_count)
	Whether a I/O operation should be retried later. More...

bool	my_net_write (NET net, const uchar packet, size_t len)
	Write a logical packet with packet header. More...

static void	reset_packet_write_state (NET *net)

static int	begin_packet_write_state (NET net, uchar command, const uchar packet, size_t packet_len, const uchar *optional_prefix, size_t prefix_len)

static net_async_status	net_write_vector_nonblocking (NET net, ssize_t res)

net_async_status	net_write_command_nonblocking (NET net, uchar command, const uchar prefix, size_t prefix_len, const uchar packet, size_t packet_len, bool res)
	Send a command to the server in asynchronous way. More...

net_async_status	my_net_write_nonblocking (NET net, const uchar packet, size_t len, bool *res)

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. More...

static bool	net_write_raw_loop (NET net, const uchar buf, size_t count)
	Write a determined number of bytes to a network handler. More...

bool	net_write_packet (NET net, const uchar packet, size_t length)
	Write a MySQL protocol packet to the network handler. More...

static bool	net_read_raw_loop (NET *net, size_t count)
	Read a determined number of bytes from a network handler. More...

static bool	net_read_packet_header (NET *net)
	Read the header of a packet. More...

static ulong	net_read_available (NET *net, size_t count)

static net_async_status	net_read_data_nonblocking (NET net, size_t count, bool err_ptr)

static net_async_status	net_read_packet_header_nonblocking (NET net, bool err_ptr)

static net_async_status	net_read_packet_nonblocking (NET net, ulong ret)

static void	net_read_init_offsets (NET *net, size_t &start_of_packet, size_t &first_packet_offset, uint &multi_byte_packet, size_t &buf_length)
	Initialize the offsets. More...

static bool	net_read_process_buffer (NET *net, size_t &start_of_packet, size_t &buf_length, uint &multi_byte_packet, size_t &first_packet_offset)
	Read the payload length in the packet, if it is found to multipacket omit the packet header of the subsequent packets. More...

static ulong	net_read_update_offsets (NET *net, size_t start_of_packet, size_t first_packet_offset, size_t buf_length, uint multi_byte_packet)
	Update the offsets in the NET structure after reading the current packet. More...

static net_async_status	net_read_compressed_nonblocking (NET net, ulong len_ptr)

static net_async_status	net_read_uncompressed_nonblocking (NET net, ulong len_ptr)
	Read the usual packet that is not compressed asynchronously. More...

static size_t	net_read_packet (NET net, size_t complen)
	Read one (variable-length) MySQL protocol packet. More...

net_async_status	my_net_read_nonblocking (NET net, ulong len_ptr)

static void	net_read_uncompressed_packet (NET *net, size_t &len)
	Reads one packet to net->buff + net->where_b. More...

static void	net_read_compressed_packet (NET *net, size_t &len)

ulong	my_net_read (NET *net)
	Read a packet from the client/server and return it without the internal package header. More...

void	my_net_set_read_timeout (NET *net, uint timeout)

void	my_net_set_write_timeout (NET *net, uint timeout)

void	my_net_set_retry_count (NET *net, uint retry_count)

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 dynamically when reading big packets. Each logical packet has the following pre-info: 3 byte length & 1 byte package-number.

Function Documentation

◆ begin_packet_write_state()

static int begin_packet_write_state	(	NET *	net,
		uchar	command,
		const uchar *	packet,
		size_t	packet_len,
		const uchar *	optional_prefix,
		size_t	prefix_len
	)

static

◆ compress_context()

static mysql_compress_context * compress_context ( NET * net )

static

Returns the appropriate compression_context based on caller.

If the caller is server then fetch is from the server extension structure.

Parameters

[in] net NET structure

Returns: mysql_compress_context structure pointer

◆ compress_packet()

static uchar * compress_packet	(	NET *	net,
		const uchar *	packet,
		size_t *	length
	)

static

Compress and encapsulate a packet into a compressed packet.

Parameters

	net	NET handler.
	packet	The packet to compress.
[in,out]	length	Length of the packet.

See Compressed Packet Header for a description of the header structure.

Returns: Pointer to the (new) compressed packet.

◆ my_net_init()

bool my_net_init	(	NET *	net,
		Vio *	vio
	)

Init with packet info.

◆ my_net_read()

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_net_read_nonblocking()

net_async_status my_net_read_nonblocking	(	NET *	net,
		ulong *	len_ptr
	)

◆ my_net_set_read_timeout()

void my_net_set_read_timeout	(	NET *	net,
		uint	timeout
	)

◆ my_net_set_retry_count()

void my_net_set_retry_count	(	NET *	net,
		uint	retry_count
	)

◆ my_net_set_write_timeout()

void my_net_set_write_timeout	(	NET *	net,
		uint	timeout
	)

◆ my_net_write()

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!

◆ my_net_write_nonblocking()

net_async_status my_net_write_nonblocking	(	NET *	net,
		const uchar *	packet,
		size_t	len,
		bool *	res
	)

◆ net_claim_memory_ownership()

void net_claim_memory_ownership	(	NET *	net,
		bool	claim
	)

◆ net_clear()

void net_clear	(	NET *	net,
		bool	check_buffer
	)

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.

◆ net_end()

void net_end ( NET * net )

◆ net_extension_free()

void net_extension_free ( NET * net )

◆ net_extension_init()

NET_EXTENSION * net_extension_init ( )

◆ net_flush()

bool net_flush ( NET * net )

Flush write_buffer if not empty.

◆ net_read_available()

static ulong net_read_available	(	NET *	net,
		size_t	count
	)

static

◆ net_read_compressed_nonblocking()

static net_async_status net_read_compressed_nonblocking	(	NET *	net,
		ulong *	len_ptr
	)

static

◆ net_read_compressed_packet()

static void net_read_compressed_packet	(	NET *	net,
		size_t &	len
	)

static

◆ net_read_data_nonblocking()

static net_async_status net_read_data_nonblocking	(	NET *	net,
		size_t	count,
		bool *	err_ptr
	)

static

◆ net_read_init_offsets()

static void net_read_init_offsets	(	NET *	net,
		size_t &	start_of_packet,
		size_t &	first_packet_offset,
		uint &	multi_byte_packet,
		size_t &	buf_length
	)

static

Initialize the offsets.

If it is first packet then initialize the offsets from the beginning else initialize the offsets after the data last read in the old packet.

Parameters

[in,out]	net	NET structure.
[in,out]	start_of_packet	Starting offset of the packet to be read. In multipackets, points to the next header that will be erased.
[in,out]	first_packet_offset	Starting offset of the packet to read.
[in,out]	multi_byte_packet	Flag that indicate if packet is multibyte
[in,out]	buf_length	End of readable byte.

◆ net_read_packet()

static size_t net_read_packet	(	NET *	net,
		size_t *	complen
	)

static

Read one (variable-length) MySQL protocol packet.

A MySQL packet consists of a header and a payload.

Remarks: Reads one packet to net->buff + net->where_b.; Long packets are handled by my_net_read().; The network buffer is expanded if necessary.

Returns: The length of the packet, or packet_error on error.

◆ net_read_packet_header()

static bool net_read_packet_header ( NET * net )

static

Read the header of a packet.

The MySQL protocol packet header consists of the length, in bytes, of the payload (packet data) and a serial number.

Remarks: The encoded length is the length of the packet payload, which does not include the packet header.; The serial number is used to ensure that the packets are received in order. If the packet serial number does not match the expected value, a error is returned.

Parameters

net	NET handler.

Returns: true on error, false on success.

◆ net_read_packet_header_nonblocking()

static net_async_status net_read_packet_header_nonblocking	(	NET *	net,
		bool *	err_ptr
	)

static

◆ net_read_packet_nonblocking()

static net_async_status net_read_packet_nonblocking	(	NET *	net,
		ulong *	ret
	)

static

◆ net_read_process_buffer()

static bool net_read_process_buffer	(	NET *	net,
		size_t &	start_of_packet,
		size_t &	buf_length,
		uint &	multi_byte_packet,
		size_t &	first_packet_offset
	)

static

Read the payload length in the packet, if it is found to multipacket omit the packet header of the subsequent packets.

Parameters

[in,out]	net	NET structures
[in,out]	start_of_packet	In multipackets, points to the next header that will be erased
[in,out]	buf_length	End of readable byte
[in,out]	multi_byte_packet	Flag that indicate if packet is multibyte
[in,out]	first_packet_offset	Starting offset of the packet to read

Return values

true	The last packet read
false	Otherwise

◆ net_read_raw_loop()

static bool net_read_raw_loop	(	NET *	net,
		size_t	count
	)

static

Read a determined number of bytes from a network handler.

Parameters

net	NET handler.
count	The number of bytes to read.

Returns: true on error, false on success.

◆ net_read_uncompressed_nonblocking()

static net_async_status net_read_uncompressed_nonblocking	(	NET *	net,
		ulong *	len_ptr
	)

static

Read the usual packet that is not compressed asynchronously.

Parameters

[in,out]	net	NET structure
[out]	len_ptr	length of the packet read

Returns: status of the reads.

◆ net_read_uncompressed_packet()

static void net_read_uncompressed_packet	(	NET *	net,
		size_t &	len
	)

static

Reads one packet to net->buff + net->where_b.

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.

Parameters

[in,out]	net	NET structure
[out]	len	length of the packet read

◆ net_read_update_offsets()

static ulong net_read_update_offsets	(	NET *	net,
		size_t	start_of_packet,
		size_t	first_packet_offset,
		size_t	buf_length,
		uint	multi_byte_packet
	)

static

Update the offsets in the NET structure after reading the current packet.

Parameters

[in,out]	net	NET structure.
[in]	start_of_packet	In multipackets, points to the next header that will be erased.
[in]	first_packet_offset	Starting offset of the packet to read.
[in]	buf_length	End of readable byte.
[in]	multi_byte_packet	Flag that indicate if packet is multibyte

◆ net_realloc()

bool net_realloc	(	NET *	net,
		size_t	length
	)

Realloc the packet buffer.

◆ net_should_retry()

static bool net_should_retry	(	NET *	net,
		uint *	retry_count
	)

static

Whether a I/O operation should be retried later.

Parameters

net	NET handler.
retry_count	Maximum number of interrupted operations.

Return values

true	Operation should be retried.
false	Operation should not be retried. Fatal error.

◆ net_write_buff()

static bool net_write_buff	(	NET *	net,
		const uchar *	packet,
		size_t	len
	)

static

Caching the data in a local buffer before sending it.

Fill up net->buffer and send it to the client when full.

If the rest of the to-be-sent-packet is bigger than buffer, send it in one big block (to avoid copying to internal buffer). If not, copy the rest of the data to the buffer and return without sending data.

Parameters

net	Network handler
packet	Packet to send
len	Length of packet

Note: The cached buffer can be sent as it is with 'net_flush()'. In this code we have to be careful to not send a packet longer than MAX_PACKET_LENGTH to net_write_packet() if we are using the compressed protocol as we store the length of the compressed packet in 3 bytes.

Return values

0	ok
1

◆ net_write_command()

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

◆ net_write_command_nonblocking()

net_async_status net_write_command_nonblocking	(	NET *	net,
		uchar	command,
		const uchar *	prefix,
		size_t	prefix_len,
		const uchar *	packet,
		size_t	packet_len,
		bool *	res
	)

Send a command to the server in asynchronous way.

This function will first populate all headers in NET::async_write_headers, followed by payload in NET::async_write_vector. Once header and payload is populated in NET, were call net_write_vector_nonblocking to send the packets to server in an asynchronous way.

◆ net_write_packet()

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.

◆ net_write_raw_loop()

static bool net_write_raw_loop	(	NET *	net,
		const uchar *	buf,
		size_t	count
	)

static

Write a determined number of bytes to a network handler.

Parameters

net	NET handler.
buf	Buffer containing the data to be written.
count	The length, in bytes, of the buffer.

Returns: true on error, false on success.

◆ net_write_vector_nonblocking()

static net_async_status net_write_vector_nonblocking	(	NET *	net,
		ssize_t *	res
	)

static

◆ reset_packet_write_state()

static void reset_packet_write_state ( NET * net )

static

◆ thd_increment_bytes_received()

void thd_increment_bytes_received ( size_t length )

◆ thd_increment_bytes_sent()

void thd_increment_bytes_sent ( size_t length )

Functions

Detailed Description

Function Documentation

◆ begin_packet_write_state()

◆ compress_context()

◆ compress_packet()

◆ my_net_init()

◆ my_net_read()

◆ my_net_read_nonblocking()

◆ my_net_set_read_timeout()

◆ my_net_set_retry_count()

◆ my_net_set_write_timeout()

◆ my_net_write()

◆ my_net_write_nonblocking()

◆ net_claim_memory_ownership()

◆ net_clear()

◆ net_end()

◆ net_extension_free()

◆ net_extension_init()

◆ net_flush()

◆ net_read_available()

◆ net_read_compressed_nonblocking()

◆ net_read_compressed_packet()

◆ net_read_data_nonblocking()

◆ net_read_init_offsets()

◆ net_read_packet()

◆ net_read_packet_header()

◆ net_read_packet_header_nonblocking()

◆ net_read_packet_nonblocking()

◆ net_read_process_buffer()

◆ net_read_raw_loop()

◆ net_read_uncompressed_nonblocking()

◆ net_read_uncompressed_packet()

◆ net_read_update_offsets()

◆ net_realloc()

◆ net_should_retry()

◆ net_write_buff()

◆ net_write_command()

◆ net_write_command_nonblocking()

◆ net_write_packet()

◆ net_write_raw_loop()

◆ net_write_vector_nonblocking()

◆ reset_packet_write_state()

◆ thd_increment_bytes_received()

◆ thd_increment_bytes_sent()