hcq/MaxScale
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
Files
fb52e565fe36877eb39eb5d3a93ef42f4834e65a
MaxScale/include/maxscale/dcb.h
Markus Mäkelä a8eda7342f Make writeqlen and others uint64_t 
This prevents them from overflowing with buffered results larger than can
be expressed with 32 bits.
2018-10-20 11:53:57 +03:00

462 lines
20 KiB
C
Raw Blame History

/*
* Copyright (c) 2018 MariaDB Corporation Ab
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
*
* Change Date: 2022-01-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2 or later of the General
* Public License.
*/
#pragma once
/**
* @file dcb.h The Descriptor Control Block
*/
#include <maxscale/cdefs.h>
#include <netinet/in.h>
#include <maxbase/poll.h>
#include <maxscale/authenticator.h>
#include <maxscale/buffer.h>
#include <maxscale/log.h>
#include <maxscale/modinfo.h>
#include <maxscale/protocol.h>
#include <maxscale/ssl.h>
MXS_BEGIN_DECLS
#define ERRHANDLE
struct session;
struct server;
struct service;
struct servlistener;
struct dcb;
#define DCBFD_CLOSED -1
/**
* The statistics gathered on a descriptor control block
*/
typedef struct dcbstats
{
int n_reads; /*< Number of reads on this descriptor */
int n_writes; /*< Number of writes on this descriptor */
int n_accepts; /*< Number of accepts on this descriptor */
int n_buffered; /*< Number of buffered writes */
int n_high_water; /*< Number of crosses of high water mark */
int n_low_water; /*< Number of crosses of low water mark */
} DCBSTATS;
#define DCBSTATS_INIT {0}
/* DCB states */
typedef enum
{
DCB_STATE_UNDEFINED, /*< State variable with no state */
DCB_STATE_ALLOC, /*< Memory allocated but not populated */
DCB_STATE_POLLING, /*< Waiting in the poll loop */
DCB_STATE_LISTENING, /*< The DCB is for a listening socket */
DCB_STATE_DISCONNECTED, /*< The socket is now closed */
DCB_STATE_NOPOLLING, /*< Removed from poll mask */
} dcb_state_t;
#define STRDCBSTATE(s) \
((s) == DCB_STATE_ALLOC ? "DCB_STATE_ALLOC" \
: ((s) == DCB_STATE_POLLING ? "DCB_STATE_POLLING" \
: ((s) == DCB_STATE_LISTENING ? "DCB_STATE_LISTENING" \
: ((s) \
== \
DCB_STATE_DISCONNECTED \
? \
"DCB_STATE_DISCONNECTED" \
: (( \
s) \
== \
DCB_STATE_NOPOLLING \
? \
"DCB_STATE_NOPOLLING" \
: (( \
s) \
== \
DCB_STATE_UNDEFINED \
? \
"DCB_STATE_UNDEFINED" \
: \
"DCB_STATE_UNKNOWN"))))))
typedef enum
{
DCB_ROLE_SERVICE_LISTENER, /*< Receives initial connect requests from clients */
DCB_ROLE_CLIENT_HANDLER, /*< Serves dedicated client */
DCB_ROLE_BACKEND_HANDLER, /*< Serves back end connection */
DCB_ROLE_INTERNAL /*< Internal DCB not connected to the outside */
} dcb_role_t;
#define STRDCBROLE(r) \
((r) == DCB_ROLE_SERVICE_LISTENER ? "DCB_ROLE_SERVICE_LISTENER" \
: ((r) == DCB_ROLE_CLIENT_HANDLER ? "DCB_ROLE_CLIENT_HANDLER" \
: ((r) \
== DCB_ROLE_BACKEND_HANDLER \
? "DCB_ROLE_BACKEND_HANDLER" \
: (( \
r) \
== \
DCB_ROLE_INTERNAL \
? \
"DCB_ROLE_INTERNAL" \
: \
"UNKNOWN DCB ROLE"))))
#define DCB_STRTYPE(dcb) \
(dcb->dcb_role == DCB_ROLE_CLIENT_HANDLER ? "Client DCB" \
: dcb->dcb_role == DCB_ROLE_BACKEND_HANDLER ? "Backend DCB" \
: dcb->dcb_role \
== DCB_ROLE_SERVICE_LISTENER ? "Listener DCB" \
: \
dcb->dcb_role == DCB_ROLE_INTERNAL ? "Internal DCB" : "Unknown DCB")
/**
* Callback reasons for the DCB callback mechanism.
*/
typedef enum
{
DCB_REASON_CLOSE, /*< The DCB is closing */
DCB_REASON_DRAINED, /*< The write delay queue has drained */
DCB_REASON_HIGH_WATER, /*< Cross high water mark */
DCB_REASON_LOW_WATER, /*< Cross low water mark */
DCB_REASON_ERROR, /*< An error was flagged on the connection */
DCB_REASON_HUP, /*< A hangup was detected */
DCB_REASON_NOT_RESPONDING /*< Server connection was lost */
} DCB_REASON;
/**
* Callback structure - used to track callbacks registered on a DCB
*/
typedef struct dcb_callback
{
DCB_REASON reason; /*< The reason for the callback */
int (* cb)(struct dcb* dcb, DCB_REASON reason, void* userdata);
void* userdata; /*< User data to be sent in the callback */
struct dcb_callback* next; /*< Next callback for this DCB */
} DCB_CALLBACK;
/**
* State of SSL connection
*/
typedef enum
{
SSL_HANDSHAKE_UNKNOWN, /*< The DCB has unknown SSL status */
SSL_HANDSHAKE_REQUIRED, /*< SSL handshake is needed */
SSL_HANDSHAKE_DONE, /*< The SSL handshake completed OK */
SSL_ESTABLISHED, /*< The SSL connection is in use */
SSL_HANDSHAKE_FAILED /*< The SSL handshake failed */
} SSL_STATE;
/**
* Descriptor Control Block
*
* A wrapper for a network descriptor within the gateway, it contains all the
* state information necessary to allow for the implementation of the asynchronous
* operation of the protocol and gateway functions. It also provides links to the service
* and session data that is required to route the information within the gateway.
*
* It is important to hold the state information here such that any thread within the
* gateway may be selected to execute the required actions when a network event occurs.
*
* Note that the first few fields (up to and including "entry_is_ready") must
* precisely match the LIST_ENTRY structure defined in the list manager.
*/
typedef struct dcb
{
MXB_POLL_DATA poll;
bool dcb_errhandle_called; /*< this can be called only once */
dcb_role_t dcb_role;
int fd; /**< The descriptor */
dcb_state_t state; /**< Current descriptor state */
SSL_STATE ssl_state; /**< Current state of SSL if in use */
int flags; /**< DCB flags */
char* remote; /**< Address of remote end */
char* user; /**< User name for connection */
struct sockaddr_storage ip; /**< remote IPv4/IPv6 address */
char* protoname; /**< Name of the protocol */
void* protocol; /**< The protocol specific state */
size_t protocol_packet_length; /**< How long the protocol specific packet is */
size_t protocol_bytes_processed; /**< How many bytes of a packet have been read */
struct session* session; /**< The owning session */
struct servlistener* listener; /**< For a client DCB, the listener data */
MXS_PROTOCOL func; /**< The protocol functions for this descriptor */
MXS_AUTHENTICATOR authfunc; /**< The authenticator functions for this descriptor
* */
uint64_t writeqlen; /**< Current number of byes in the write queue */
uint64_t high_water; /**< High water mark of write queue */
uint64_t low_water; /**< Low water mark of write queue */
GWBUF* writeq; /**< Write Data Queue */
GWBUF* delayq; /**< Delay Backend Write Data Queue */
GWBUF* readq; /**< Read queue for storing incomplete reads */
GWBUF* fakeq; /**< Fake event queue for generated events */
uint32_t fake_event; /**< Fake event to be delivered to handler */
DCBSTATS stats; /**< DCB related statistics */
struct dcb* nextpersistent; /**< Next DCB in the persistent pool for SERVER */
time_t persistentstart; /**< 0: Not in the persistent pool.
* -1: Evicted from the persistent pool and being closed.
* non-0: Time when placed in the persistent pool.
*/
struct service* service; /**< The related service */
void* data; /**< Specific client data, shared between DCBs of this session */
void* authenticator_data; /**< The authenticator data for this DCB */
DCB_CALLBACK* callbacks; /**< The list of callbacks for the DCB */
int64_t last_read; /*< Last time the DCB received data */
struct server* server; /**< The associated backend server */
SSL* ssl; /*< SSL struct for connection */
bool ssl_read_want_read; /*< Flag */
bool ssl_read_want_write; /*< Flag */
bool ssl_write_want_read; /*< Flag */
bool ssl_write_want_write; /*< Flag */
bool was_persistent; /**< Whether this DCB was in the persistent pool */
bool high_water_reached; /** High water mark reached, to determine whether need release
* throttle */
struct
{
struct dcb* next; /**< Next DCB in owning thread's list */
struct dcb* tail; /**< Last DCB in owning thread's list */
} thread;
uint32_t n_close; /** How many times dcb_close has been called. */
char* path; /** If a Unix socket, the path it was bound to. */
} DCB;
/**
* The DCB usage filer used for returning DCB's in use for a certain reason
*/
typedef enum
{
DCB_USAGE_CLIENT,
DCB_USAGE_LISTENER,
DCB_USAGE_BACKEND,
DCB_USAGE_INTERNAL,
DCB_USAGE_ALL
} DCB_USAGE;
/* A few useful macros */
#define DCB_SESSION(x) (x)->session
#define DCB_PROTOCOL(x, type) (type*)((x)->protocol)
#define DCB_WRITEQLEN(x) (x)->writeqlen
#define DCB_SET_LOW_WATER(x, lo) (x)->low_water = (lo);
#define DCB_SET_HIGH_WATER(x, hi) (x)->low_water = (hi);
#define DCB_BELOW_LOW_WATER(x) ((x)->low_water && (x)->writeqlen < (x)->low_water)
#define DCB_ABOVE_HIGH_WATER(x) ((x)->high_water && (x)->writeqlen > (x)->high_water)
#define DCB_THROTTLING_ENABLED(x) ((x)->high_water && (x)->low_water)
/**
* @brief DCB system initialization function
*
* This function needs to be the first function call into this system.
*/
void dcb_global_init();
int dcb_write(DCB*, GWBUF*);
DCB* dcb_accept(DCB* listener);
DCB* dcb_alloc(dcb_role_t, struct servlistener*);
DCB* dcb_connect(struct server*, struct session*, const char*);
int dcb_read(DCB*, GWBUF**, int);
int dcb_drain_writeq(DCB*);
void dcb_close(DCB*);
/**
* @brief Close DCB in the thread that owns it.
*
* @param dcb The dcb to be closed.
*
* @note Even if the calling thread owns the dcb, the closing will
* still be made via the event loop.
*/
void dcb_close_in_owning_thread(DCB* dcb);
void printAllDCBs(); /* Debug to print all DCB in
* the system */
void printDCB(DCB*); /* Debug print routine */
void dprintDCBList(DCB*); /* Debug print DCB list
* statistics */
void dprintAllDCBs(DCB*); /* Debug to print all DCB in
* the system */
void dprintOneDCB(DCB*, DCB*); /* Debug to print one DCB */
void dprintDCB(DCB*, DCB*); /* Debug to print a DCB in the
* system */
void dListDCBs(DCB*); /* List all DCBs in the system
* */
void dListClients(DCB*); /* List al the client DCBs */
const char* gw_dcb_state2string(dcb_state_t); /* DCB state to string */
void dcb_printf(DCB*, const char*, ...) __attribute__ ((format(printf, 2, 3))); /* DCB version of printf */
int dcb_add_callback(DCB*, DCB_REASON, int (*)(struct dcb*, DCB_REASON, void*), void*);
int dcb_remove_callback(DCB*, DCB_REASON, int (*)(struct dcb*, DCB_REASON, void*), void*);
int dcb_count_by_usage(DCB_USAGE); /* Return counts of DCBs */
int dcb_persistent_clean_count(DCB*, int, bool); /* Clean persistent and return count */
void dcb_hangup_foreach(struct server* server);
uint64_t dcb_get_session_id(DCB* dcb);
char* dcb_role_name(DCB*); /* Return the name of a role */
int dcb_accept_SSL(DCB* dcb);
int dcb_connect_SSL(DCB* dcb);
int dcb_listen(DCB* listener, const char* config, const char* protocol_name);
void dcb_enable_session_timeouts();
void dcb_process_idle_sessions(int thr);
/**
* @brief Append a buffer the DCB's readqueue
*
* Usually data is stored into the DCB's readqueue when not enough data is
* available and the processing needs to be deferred until more data is available.
*
* @param dcb The DCB to be appended to.
* @param buffer The buffer to append.
*/
static inline void dcb_readq_append(DCB* dcb, GWBUF* buffer)
{
dcb->readq = gwbuf_append(dcb->readq, buffer);
}
/**
* @brief Returns the read queue of the DCB.
*
* @note The read queue remains the property of the DCB.
*
* @return A buffer of NULL if there is no read queue.
*/
static GWBUF* dcb_readq_get(DCB* dcb)
{
return dcb->readq;
}
/**
* @brief Returns whether a DCB currently has a read queue.
*
* @return True, if the DCB has a read queue, otherwise false.
*/
static inline bool dcb_readq_has(DCB* dcb)
{
return dcb->readq != NULL;
}
/**
* @brief Returns the current length of the read queue
*
* @return Length of read queue
*/
static unsigned int dcb_readq_length(DCB* dcb)
{
return dcb->readq ? gwbuf_length(dcb->readq) : 0;
}
/**
* @brief Prepend a buffer the DCB's readqueue
*
* @param dcb The DCB to be prepended to.
* @param buffer The buffer to prepend
*/
static inline void dcb_readq_prepend(DCB* dcb, GWBUF* buffer)
{
dcb->readq = gwbuf_append(buffer, dcb->readq);
}
/**
* @brief Returns the read queue of the DCB and sets the read queue to NULL.
*
* @note The read queue becomes the property of the caller.
*
* @return A buffer of NULL if there is no read queue.
*/
static GWBUF* dcb_readq_release(DCB* dcb)
{
GWBUF* readq = dcb->readq;
dcb->readq = NULL;
return readq;
}
/**
* @brief Set read queue of a DCB
*
* The expectation is that there is no readqueue when this is done.
* The ownership of the provided buffer moved to the DCB.
*
* @param dcb The DCB to be reset.
* @param buffer The buffer to reset with
*/
static inline void dcb_readq_set(DCB* dcb, GWBUF* buffer)
{
if (dcb->readq)
{
MXS_ERROR("Read-queue set when there already is a read-queue.");
// TODO: Conceptually this should be freed here. However, currently
// TODO: the code just assigns without checking, so we do the same
// TODO: for now. If this is not set to NULL when it has been consumed,
// TODO: we would get a double free.
// TODO: gwbuf_free(dcb->readq);
dcb->readq = NULL;
}
dcb->readq = buffer;
}
/**
* @brief Call a function for each connected DCB
*
* @deprecated You should not use this function, use dcb_foreach_parallel instead
*
* @warning This must only be called from the main thread, otherwise deadlocks occur
*
* @param func Function to call. The function should return @c true to continue iteration
* and @c false to stop iteration earlier. The first parameter is a DCB and the second
* is the value of @c data that the user provided.
* @param data User provided data passed as the second parameter to @c func
* @return True if all DCBs were iterated, false if the callback returned false
*/
bool dcb_foreach(bool (* func)(DCB* dcb, void* data), void* data);
/**
* @brief Call a function for each connected DCB on the current worker
*
* @param func Function to call. The function should return @c true to continue
* iteration and @c false to stop iteration earlier. The first parameter
* is the current DCB.
*
* @param data User provided data passed as the second parameter to @c func
*/
void dcb_foreach_local(bool (* func)(DCB* dcb, void* data), void* data);
/**
* @brief Return the port number this DCB is connected to
*
* @param dcb DCB to inspect
* @return Port number the DCB is connected to or -1 if information is not available
*/
int dcb_get_port(const DCB* dcb);
/**
* @brief Return the DCB currently being handled by the calling thread.
*
* @return A DCB, or NULL if the calling thread is not currently handling
* a DCB or if the calling thread is not a polling/worker thread.
*/
DCB* dcb_get_current();
/**
* Get JSON representation of the DCB
*
* @param dcb DCB to convert to JSON
*
* @return The JSON representation
*/
json_t* dcb_to_json(DCB* dcb);
/**
* DCB flags values
*/
#define DCBF_HUNG 0x0002 /*< Hangup has been dispatched */
#define DCBF_REPLIED 0x0004 /*< DCB was written to */
#define DCB_REPLIED(d) ((d)->flags & DCBF_REPLIED)
MXS_END_DECLS
Reference in New Issue View Git Blame Copy Permalink