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KILL [CONNECTION | QUERY] support, part2

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MySQL sessions are added to a hasmap when created, removed when closed.
MYSQL_COM_PROCESS_KILL is now detected, the thread_id is read and the kill
command sent to all worker threads to find the correct session. If found, a
fake hangup even is created for the client dcb.

As is, this function is of little use since the client could just disconnect
itself instead. Later on, additional commands of this nature will be  added.
This commit is contained in:
Esa Korhonen
2017-05-02 10:05:19 +03:00
parent f66620c89c
commit 17f6e94cba
6 changed files with 247 additions and 60 deletions
Download Patch File Download Diff File Expand all files Collapse all files

132
server/modules/protocol/MySQL/MySQLClient/mysql_client.c
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@ -12,40 +12,6 @@
* Public License.
*/
/**
* @file mysql_client.c
*
* MySQL Protocol module for handling the protocol between the gateway
* and the client.
*
* Revision History
* Date Who Description
* 14/06/2013 Mark Riddoch Initial version
* 17/06/2013 Massimiliano Pinto Added Client To MaxScale routines
* 24/06/2013 Massimiliano Pinto Added: fetch passwords from service users' hashtable
* 02/09/2013 Massimiliano Pinto Added: session refcount
* 16/12/2013 Massimiliano Pinto Added: client closed socket detection with recv(..., MSG_PEEK)
* 24/02/2014 Massimiliano Pinto Added: on failed authentication a new users' table is loaded
* with time and frequency limitations
* If current user is authenticated the new users' table will
* replace the old one
* 28/02/2014 Massimiliano Pinto Added: client IPv4 in dcb->ipv4 and inet_ntop for string
* representation
* 11/03/2014 Massimiliano Pinto Added: Unix socket support
* 07/05/2014 Massimiliano Pinto Added: specific version string in server handshake
* 09/09/2014 Massimiliano Pinto Added: 777 permission for socket path
* 13/10/2014 Massimiliano Pinto Added: dbname authentication check
* 10/11/2014 Massimiliano Pinto Added: client charset added to protocol struct
* 29/05/2015 Markus Makela Added SSL support
* 11/06/2015 Martin Brampton COM_QUIT suppressed for persistent connections
* 04/09/2015 Martin Brampton Introduce DUMMY session to fulfill guarantee DCB always has session
* 09/09/2015 Martin Brampton Modify error handler calls
* 11/01/2016 Martin Brampton Remove SSL write code, now handled at lower level;
* replace gwbuf_consume by gwbuf_free (multiple).
* 07/02/2016 Martin Brampton Split off authentication and SSL.
* 31/05/2016 Martin Brampton Implement connection throttling
*/
#define MXS_MODULE_NAME "MySQLClient"
#include <maxscale/protocol.h>
@ -61,6 +27,7 @@
#include <maxscale/query_classifier.h>
#include <maxscale/authenticator.h>
#include <maxscale/session.h>
#include <maxscale/worker.h>
static int process_init(void);
static void process_finish(void);
@ -85,12 +52,12 @@ static int gw_read_normal_data(DCB *dcb, GWBUF *read_buffer, int nbytes_read);
static int gw_read_finish_processing(DCB *dcb, GWBUF *read_buffer, uint64_t capabilities);
static bool ensure_complete_packet(DCB *dcb, GWBUF **read_buffer, int nbytes_read);
static void gw_process_one_new_client(DCB *client_dcb);
static bool process_special_commands(DCB* client_dcb, GWBUF *read_buffer, int nbytes_read);
/*
* The "module object" for the mysqld client protocol module.
*/
/**
* The module entry point routine. It is this routine that
* must populate the structure that is referred to as the
@ -709,6 +676,8 @@ gw_read_do_authentication(DCB *dcb, GWBUF *read_buffer, int nbytes_read)
ss_dassert(session->state != SESSION_STATE_ALLOC &&
session->state != SESSION_STATE_DUMMY);
protocol->protocol_auth_state = MXS_AUTH_STATE_COMPLETE;
ss_debug(bool check =) mxs_add_to_session_map(session->ses_id, session);
ss_dassert(check);
mxs_mysql_send_ok(dcb, next_sequence, 0, NULL);
}
else
@ -933,33 +902,14 @@ gw_read_normal_data(DCB *dcb, GWBUF *read_buffer, int nbytes_read)
if (nbytes_read < 3 || nbytes_read <
(MYSQL_GET_PAYLOAD_LEN((uint8_t *) GWBUF_DATA(read_buffer)) + 4))
{
dcb->dcb_readqueue = read_buffer;
return 0;
}
}
/**
* Handle COM_SET_OPTION. This seems to be only used by some versions of PHP.
*
* The option is stored as a two byte integer with the values 0 for enabling
* multi-statements and 1 for disabling it.
*/
MySQLProtocol *proto = dcb->protocol;
uint8_t opt;
if (proto->current_command == MYSQL_COM_SET_OPTION &&
gwbuf_copy_data(read_buffer, MYSQL_HEADER_LEN + 2, 1, &opt))
if (!process_special_commands(dcb, read_buffer, nbytes_read))
{
if (opt)
{
proto->client_capabilities &= ~GW_MYSQL_CAPABILITIES_MULTI_STATEMENTS;
}
else
{
proto->client_capabilities |= GW_MYSQL_CAPABILITIES_MULTI_STATEMENTS;
}
return 0;
}
return gw_read_finish_processing(dcb, read_buffer, capabilities);
@ -1307,7 +1257,10 @@ static int gw_client_close(DCB *dcb)
CHK_DCB(dcb);
ss_dassert(dcb->protocol);
mysql_protocol_done(dcb);
session_close(dcb->session);
MXS_SESSION* target = dcb->session;
ss_debug(MXS_SESSION* removed =) mxs_remove_from_session_map(target->ses_id);
ss_dassert(removed == target);
session_close(target);
return 1;
}
@ -1526,3 +1479,68 @@ static bool ensure_complete_packet(DCB *dcb, GWBUF **read_buffer, int nbytes_rea
return true;
}
/**
* Some SQL commands/queries need to be detected and handled by the protocol
* and MaxScale instead of being routed forward as is.
* @param dcb Client dcb
* @param read_buffer the current read buffer
* @param nbytes_read How many bytes were read
* @return true if read buffer should be sent forward to routing, false if more
* data is required or processing is complete
*/
static bool process_special_commands(DCB* dcb, GWBUF *read_buffer, int nbytes_read)
{
/**
* Handle COM_SET_OPTION. This seems to be only used by some versions of PHP.
*
* The option is stored as a two byte integer with the values 0 for enabling
* multi-statements and 1 for disabling it.
*/
MySQLProtocol *proto = dcb->protocol;
uint8_t opt;
if (proto->current_command == MYSQL_COM_SET_OPTION &&
gwbuf_copy_data(read_buffer, MYSQL_HEADER_LEN + 2, 1, &opt))
{
if (opt)
{
proto->client_capabilities &= ~GW_MYSQL_CAPABILITIES_MULTI_STATEMENTS;
}
else
{
proto->client_capabilities |= GW_MYSQL_CAPABILITIES_MULTI_STATEMENTS;
}
}
/**
* Handle COM_PROCESS_KILL
*/
else if((proto->current_command == MYSQL_COM_PROCESS_KILL))
{
/* Make sure we have a complete SQL packet before trying to read the
* process id. If not, try again next time. */
unsigned int expected_len =
MYSQL_GET_PAYLOAD_LEN((uint8_t *)GWBUF_DATA(read_buffer)) + MYSQL_HEADER_LEN;
if (gwbuf_length(read_buffer) < expected_len)
{
dcb->dcb_readqueue = read_buffer;
return false;
}
else
{
uint8_t bytes[4];
if (gwbuf_copy_data(read_buffer, MYSQL_HEADER_LEN + 1, sizeof(bytes), (uint8_t*)bytes)
== sizeof(bytes))
{
uint32_t process_id = gw_mysql_get_byte4(bytes);
// Do not send this packet for routing
gwbuf_free(read_buffer);
session_broadcast_kill_command(dcb->session, process_id);
// Even if id not found, send ok. TODO: send a correct response to client
mxs_mysql_send_ok(dcb, 1, 0, NULL);
return false;
}
}
}
return true;
}