michael@0: /*
michael@0:  * Copyright (c) 2008-2012 Niels Provos and Nick Mathewson
michael@0:  *
michael@0:  * Redistribution and use in source and binary forms, with or without
michael@0:  * modification, are permitted provided that the following conditions
michael@0:  * are met:
michael@0:  * 1. Redistributions of source code must retain the above copyright
michael@0:  *    notice, this list of conditions and the following disclaimer.
michael@0:  * 2. Redistributions in binary form must reproduce the above copyright
michael@0:  *    notice, this list of conditions and the following disclaimer in the
michael@0:  *    documentation and/or other materials provided with the distribution.
michael@0:  * 3. The name of the author may not be used to endorse or promote products
michael@0:  *    derived from this software without specific prior written permission.
michael@0:  *
michael@0:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
michael@0:  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
michael@0:  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
michael@0:  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
michael@0:  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
michael@0:  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
michael@0:  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
michael@0:  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
michael@0:  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
michael@0:  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0:  */
michael@0: #ifndef _BUFFEREVENT_INTERNAL_H_
michael@0: #define _BUFFEREVENT_INTERNAL_H_
michael@0: 
michael@0: #ifdef __cplusplus
michael@0: extern "C" {
michael@0: #endif
michael@0: 
michael@0: #include "event2/event-config.h"
michael@0: #include "event2/util.h"
michael@0: #include "defer-internal.h"
michael@0: #include "evthread-internal.h"
michael@0: #include "event2/thread.h"
michael@0: #include "ratelim-internal.h"
michael@0: #include "event2/bufferevent_struct.h"
michael@0: 
michael@0: /* These flags are reasons that we might be declining to actually enable
michael@0:    reading or writing on a bufferevent.
michael@0:  */
michael@0: 
michael@0: /* On a all bufferevents, for reading: used when we have read up to the
michael@0:    watermark value.
michael@0: 
michael@0:    On a filtering bufferevent, for writing: used when the underlying
michael@0:    bufferevent's write buffer has been filled up to its watermark
michael@0:    value.
michael@0: */
michael@0: #define BEV_SUSPEND_WM 0x01
michael@0: /* On a base bufferevent: when we have emptied a bandwidth buckets */
michael@0: #define BEV_SUSPEND_BW 0x02
michael@0: /* On a base bufferevent: when we have emptied the group's bandwidth bucket. */
michael@0: #define BEV_SUSPEND_BW_GROUP 0x04
michael@0: /* On a socket bufferevent: can't do any operations while we're waiting for
michael@0:  * name lookup to finish. */
michael@0: #define BEV_SUSPEND_LOOKUP 0x08
michael@0: /* On a base bufferevent, for reading: used when a filter has choked this
michael@0:  * (underlying) bufferevent because it has stopped reading from it. */
michael@0: #define BEV_SUSPEND_FILT_READ 0x10
michael@0: 
michael@0: typedef ev_uint16_t bufferevent_suspend_flags;
michael@0: 
michael@0: struct bufferevent_rate_limit_group {
michael@0: 	/** List of all members in the group */
michael@0: 	TAILQ_HEAD(rlim_group_member_list, bufferevent_private) members;
michael@0: 	/** Current limits for the group. */
michael@0: 	struct ev_token_bucket rate_limit;
michael@0: 	struct ev_token_bucket_cfg rate_limit_cfg;
michael@0: 
michael@0: 	/** True iff we don't want to read from any member of the group.until
michael@0: 	 * the token bucket refills.  */
michael@0: 	unsigned read_suspended : 1;
michael@0: 	/** True iff we don't want to write from any member of the group.until
michael@0: 	 * the token bucket refills.  */
michael@0: 	unsigned write_suspended : 1;
michael@0: 	/** True iff we were unable to suspend one of the bufferevents in the
michael@0: 	 * group for reading the last time we tried, and we should try
michael@0: 	 * again. */
michael@0: 	unsigned pending_unsuspend_read : 1;
michael@0: 	/** True iff we were unable to suspend one of the bufferevents in the
michael@0: 	 * group for writing the last time we tried, and we should try
michael@0: 	 * again. */
michael@0: 	unsigned pending_unsuspend_write : 1;
michael@0: 
michael@0: 	/*@{*/
michael@0: 	/** Total number of bytes read or written in this group since last
michael@0: 	 * reset. */
michael@0: 	ev_uint64_t total_read;
michael@0: 	ev_uint64_t total_written;
michael@0: 	/*@}*/
michael@0: 
michael@0: 	/** The number of bufferevents in the group. */
michael@0: 	int n_members;
michael@0: 
michael@0: 	/** The smallest number of bytes that any member of the group should
michael@0: 	 * be limited to read or write at a time. */
michael@0: 	ev_ssize_t min_share;
michael@0: 	ev_ssize_t configured_min_share;
michael@0: 
michael@0: 	/** Timeout event that goes off once a tick, when the bucket is ready
michael@0: 	 * to refill. */
michael@0: 	struct event master_refill_event;
michael@0: 	/** Lock to protect the members of this group.  This lock should nest
michael@0: 	 * within every bufferevent lock: if you are holding this lock, do
michael@0: 	 * not assume you can lock another bufferevent. */
michael@0: 	void *lock;
michael@0: };
michael@0: 
michael@0: /** Fields for rate-limiting a single bufferevent. */
michael@0: struct bufferevent_rate_limit {
michael@0: 	/* Linked-list elements for storing this bufferevent_private in a
michael@0: 	 * group.
michael@0: 	 *
michael@0: 	 * Note that this field is supposed to be protected by the group
michael@0: 	 * lock */
michael@0: 	TAILQ_ENTRY(bufferevent_private) next_in_group;
michael@0: 	/** The rate-limiting group for this bufferevent, or NULL if it is
michael@0: 	 * only rate-limited on its own. */
michael@0: 	struct bufferevent_rate_limit_group *group;
michael@0: 
michael@0: 	/* This bufferevent's current limits. */
michael@0: 	struct ev_token_bucket limit;
michael@0: 	/* Pointer to the rate-limit configuration for this bufferevent.
michael@0: 	 * Can be shared.  XXX reference-count this? */
michael@0: 	struct ev_token_bucket_cfg *cfg;
michael@0: 
michael@0: 	/* Timeout event used when one this bufferevent's buckets are
michael@0: 	 * empty. */
michael@0: 	struct event refill_bucket_event;
michael@0: };
michael@0: 
michael@0: /** Parts of the bufferevent structure that are shared among all bufferevent
michael@0:  * types, but not exposed in bufferevent_struct.h. */
michael@0: struct bufferevent_private {
michael@0: 	/** The underlying bufferevent structure. */
michael@0: 	struct bufferevent bev;
michael@0: 
michael@0: 	/** Evbuffer callback to enforce watermarks on input. */
michael@0: 	struct evbuffer_cb_entry *read_watermarks_cb;
michael@0: 
michael@0: 	/** If set, we should free the lock when we free the bufferevent. */
michael@0: 	unsigned own_lock : 1;
michael@0: 
michael@0: 	/** Flag: set if we have deferred callbacks and a read callback is
michael@0: 	 * pending. */
michael@0: 	unsigned readcb_pending : 1;
michael@0: 	/** Flag: set if we have deferred callbacks and a write callback is
michael@0: 	 * pending. */
michael@0: 	unsigned writecb_pending : 1;
michael@0: 	/** Flag: set if we are currently busy connecting. */
michael@0: 	unsigned connecting : 1;
michael@0: 	/** Flag: set if a connect failed prematurely; this is a hack for
michael@0: 	 * getting around the bufferevent abstraction. */
michael@0: 	unsigned connection_refused : 1;
michael@0: 	/** Set to the events pending if we have deferred callbacks and
michael@0: 	 * an events callback is pending. */
michael@0: 	short eventcb_pending;
michael@0: 
michael@0: 	/** If set, read is suspended until one or more conditions are over.
michael@0: 	 * The actual value here is a bitfield of those conditions; see the
michael@0: 	 * BEV_SUSPEND_* flags above. */
michael@0: 	bufferevent_suspend_flags read_suspended;
michael@0: 
michael@0: 	/** If set, writing is suspended until one or more conditions are over.
michael@0: 	 * The actual value here is a bitfield of those conditions; see the
michael@0: 	 * BEV_SUSPEND_* flags above. */
michael@0: 	bufferevent_suspend_flags write_suspended;
michael@0: 
michael@0: 	/** Set to the current socket errno if we have deferred callbacks and
michael@0: 	 * an events callback is pending. */
michael@0: 	int errno_pending;
michael@0: 
michael@0: 	/** The DNS error code for bufferevent_socket_connect_hostname */
michael@0: 	int dns_error;
michael@0: 
michael@0: 	/** Used to implement deferred callbacks */
michael@0: 	struct deferred_cb deferred;
michael@0: 
michael@0: 	/** The options this bufferevent was constructed with */
michael@0: 	enum bufferevent_options options;
michael@0: 
michael@0: 	/** Current reference count for this bufferevent. */
michael@0: 	int refcnt;
michael@0: 
michael@0: 	/** Lock for this bufferevent.  Shared by the inbuf and the outbuf.
michael@0: 	 * If NULL, locking is disabled. */
michael@0: 	void *lock;
michael@0: 
michael@0: 	/** Rate-limiting information for this bufferevent */
michael@0: 	struct bufferevent_rate_limit *rate_limiting;
michael@0: };
michael@0: 
michael@0: /** Possible operations for a control callback. */
michael@0: enum bufferevent_ctrl_op {
michael@0: 	BEV_CTRL_SET_FD,
michael@0: 	BEV_CTRL_GET_FD,
michael@0: 	BEV_CTRL_GET_UNDERLYING,
michael@0: 	BEV_CTRL_CANCEL_ALL
michael@0: };
michael@0: 
michael@0: /** Possible data types for a control callback */
michael@0: union bufferevent_ctrl_data {
michael@0: 	void *ptr;
michael@0: 	evutil_socket_t fd;
michael@0: };
michael@0: 
michael@0: /**
michael@0:    Implementation table for a bufferevent: holds function pointers and other
michael@0:    information to make the various bufferevent types work.
michael@0: */
michael@0: struct bufferevent_ops {
michael@0: 	/** The name of the bufferevent's type. */
michael@0: 	const char *type;
michael@0: 	/** At what offset into the implementation type will we find a
michael@0: 	    bufferevent structure?
michael@0: 
michael@0: 	    Example: if the type is implemented as
michael@0: 	    struct bufferevent_x {
michael@0: 	       int extra_data;
michael@0: 	       struct bufferevent bev;
michael@0: 	    }
michael@0: 	    then mem_offset should be offsetof(struct bufferevent_x, bev)
michael@0: 	*/
michael@0: 	off_t mem_offset;
michael@0: 
michael@0: 	/** Enables one or more of EV_READ|EV_WRITE on a bufferevent.  Does
michael@0: 	    not need to adjust the 'enabled' field.  Returns 0 on success, -1
michael@0: 	    on failure.
michael@0: 	 */
michael@0: 	int (*enable)(struct bufferevent *, short);
michael@0: 
michael@0: 	/** Disables one or more of EV_READ|EV_WRITE on a bufferevent.  Does
michael@0: 	    not need to adjust the 'enabled' field.  Returns 0 on success, -1
michael@0: 	    on failure.
michael@0: 	 */
michael@0: 	int (*disable)(struct bufferevent *, short);
michael@0: 
michael@0: 	/** Free any storage and deallocate any extra data or structures used
michael@0: 	    in this implementation.
michael@0: 	 */
michael@0: 	void (*destruct)(struct bufferevent *);
michael@0: 
michael@0: 	/** Called when the timeouts on the bufferevent have changed.*/
michael@0: 	int (*adj_timeouts)(struct bufferevent *);
michael@0: 
michael@0: 	/** Called to flush data. */
michael@0: 	int (*flush)(struct bufferevent *, short, enum bufferevent_flush_mode);
michael@0: 
michael@0: 	/** Called to access miscellaneous fields. */
michael@0: 	int (*ctrl)(struct bufferevent *, enum bufferevent_ctrl_op, union bufferevent_ctrl_data *);
michael@0: 
michael@0: };
michael@0: 
michael@0: extern const struct bufferevent_ops bufferevent_ops_socket;
michael@0: extern const struct bufferevent_ops bufferevent_ops_filter;
michael@0: extern const struct bufferevent_ops bufferevent_ops_pair;
michael@0: 
michael@0: #define BEV_IS_SOCKET(bevp) ((bevp)->be_ops == &bufferevent_ops_socket)
michael@0: #define BEV_IS_FILTER(bevp) ((bevp)->be_ops == &bufferevent_ops_filter)
michael@0: #define BEV_IS_PAIR(bevp) ((bevp)->be_ops == &bufferevent_ops_pair)
michael@0: 
michael@0: #ifdef WIN32
michael@0: extern const struct bufferevent_ops bufferevent_ops_async;
michael@0: #define BEV_IS_ASYNC(bevp) ((bevp)->be_ops == &bufferevent_ops_async)
michael@0: #else
michael@0: #define BEV_IS_ASYNC(bevp) 0
michael@0: #endif
michael@0: 
michael@0: /** Initialize the shared parts of a bufferevent. */
michael@0: int bufferevent_init_common(struct bufferevent_private *, struct event_base *, const struct bufferevent_ops *, enum bufferevent_options options);
michael@0: 
michael@0: /** For internal use: temporarily stop all reads on bufev, until the conditions
michael@0:  * in 'what' are over. */
michael@0: void bufferevent_suspend_read(struct bufferevent *bufev, bufferevent_suspend_flags what);
michael@0: /** For internal use: clear the conditions 'what' on bufev, and re-enable
michael@0:  * reading if there are no conditions left. */
michael@0: void bufferevent_unsuspend_read(struct bufferevent *bufev, bufferevent_suspend_flags what);
michael@0: 
michael@0: /** For internal use: temporarily stop all writes on bufev, until the conditions
michael@0:  * in 'what' are over. */
michael@0: void bufferevent_suspend_write(struct bufferevent *bufev, bufferevent_suspend_flags what);
michael@0: /** For internal use: clear the conditions 'what' on bufev, and re-enable
michael@0:  * writing if there are no conditions left. */
michael@0: void bufferevent_unsuspend_write(struct bufferevent *bufev, bufferevent_suspend_flags what);
michael@0: 
michael@0: #define bufferevent_wm_suspend_read(b) \
michael@0: 	bufferevent_suspend_read((b), BEV_SUSPEND_WM)
michael@0: #define bufferevent_wm_unsuspend_read(b) \
michael@0: 	bufferevent_unsuspend_read((b), BEV_SUSPEND_WM)
michael@0: 
michael@0: /*
michael@0:   Disable a bufferevent.  Equivalent to bufferevent_disable(), but
michael@0:   first resets 'connecting' flag to force EV_WRITE down for sure.
michael@0: 
michael@0:   XXXX this method will go away in the future; try not to add new users.
michael@0:     See comment in evhttp_connection_reset() for discussion.
michael@0: 
michael@0:   @param bufev the bufferevent to be disabled
michael@0:   @param event any combination of EV_READ | EV_WRITE.
michael@0:   @return 0 if successful, or -1 if an error occurred
michael@0:   @see bufferevent_disable()
michael@0:  */
michael@0: int bufferevent_disable_hard(struct bufferevent *bufev, short event);
michael@0: 
michael@0: /** Internal: Set up locking on a bufferevent.  If lock is set, use it.
michael@0:  * Otherwise, use a new lock. */
michael@0: int bufferevent_enable_locking(struct bufferevent *bufev, void *lock);
michael@0: /** Internal: Increment the reference count on bufev. */
michael@0: void bufferevent_incref(struct bufferevent *bufev);
michael@0: /** Internal: Lock bufev and increase its reference count.
michael@0:  * unlocking it otherwise. */
michael@0: void _bufferevent_incref_and_lock(struct bufferevent *bufev);
michael@0: /** Internal: Decrement the reference count on bufev.  Returns 1 if it freed
michael@0:  * the bufferevent.*/
michael@0: int bufferevent_decref(struct bufferevent *bufev);
michael@0: /** Internal: Drop the reference count on bufev, freeing as necessary, and
michael@0:  * unlocking it otherwise.  Returns 1 if it freed the bufferevent. */
michael@0: int _bufferevent_decref_and_unlock(struct bufferevent *bufev);
michael@0: 
michael@0: /** Internal: If callbacks are deferred and we have a read callback, schedule
michael@0:  * a readcb.  Otherwise just run the readcb. */
michael@0: void _bufferevent_run_readcb(struct bufferevent *bufev);
michael@0: /** Internal: If callbacks are deferred and we have a write callback, schedule
michael@0:  * a writecb.  Otherwise just run the writecb. */
michael@0: void _bufferevent_run_writecb(struct bufferevent *bufev);
michael@0: /** Internal: If callbacks are deferred and we have an eventcb, schedule
michael@0:  * it to run with events "what".  Otherwise just run the eventcb. */
michael@0: void _bufferevent_run_eventcb(struct bufferevent *bufev, short what);
michael@0: 
michael@0: /** Internal: Add the event 'ev' with timeout tv, unless tv is set to 0, in
michael@0:  * which case add ev with no timeout. */
michael@0: int _bufferevent_add_event(struct event *ev, const struct timeval *tv);
michael@0: 
michael@0: /* =========
michael@0:  * These next functions implement timeouts for bufferevents that aren't doing
michael@0:  * anything else with ev_read and ev_write, to handle timeouts.
michael@0:  * ========= */
michael@0: /** Internal use: Set up the ev_read and ev_write callbacks so that
michael@0:  * the other "generic_timeout" functions will work on it.  Call this from
michael@0:  * the constructor function. */
michael@0: void _bufferevent_init_generic_timeout_cbs(struct bufferevent *bev);
michael@0: /** Internal use: Delete the ev_read and ev_write callbacks if they're pending.
michael@0:  * Call this from the destructor function. */
michael@0: int _bufferevent_del_generic_timeout_cbs(struct bufferevent *bev);
michael@0: /** Internal use: Add or delete the generic timeout events as appropriate.
michael@0:  * (If an event is enabled and a timeout is set, we add the event.  Otherwise
michael@0:  * we delete it.)  Call this from anything that changes the timeout values,
michael@0:  * that enabled EV_READ or EV_WRITE, or that disables EV_READ or EV_WRITE. */
michael@0: int _bufferevent_generic_adj_timeouts(struct bufferevent *bev);
michael@0: 
michael@0: /** Internal use: We have just successfully read data into an inbuf, so
michael@0:  * reset the read timeout (if any). */
michael@0: #define BEV_RESET_GENERIC_READ_TIMEOUT(bev)				\
michael@0: 	do {								\
michael@0: 		if (evutil_timerisset(&(bev)->timeout_read))		\
michael@0: 			event_add(&(bev)->ev_read, &(bev)->timeout_read); \
michael@0: 	} while (0)
michael@0: /** Internal use: We have just successfully written data from an inbuf, so
michael@0:  * reset the read timeout (if any). */
michael@0: #define BEV_RESET_GENERIC_WRITE_TIMEOUT(bev)				\
michael@0: 	do {								\
michael@0: 		if (evutil_timerisset(&(bev)->timeout_write))		\
michael@0: 			event_add(&(bev)->ev_write, &(bev)->timeout_write); \
michael@0: 	} while (0)
michael@0: #define BEV_DEL_GENERIC_READ_TIMEOUT(bev)	\
michael@0: 		event_del(&(bev)->ev_read)
michael@0: #define BEV_DEL_GENERIC_WRITE_TIMEOUT(bev)	\
michael@0: 		event_del(&(bev)->ev_write)
michael@0: 
michael@0: 
michael@0: /** Internal: Given a bufferevent, return its corresponding
michael@0:  * bufferevent_private. */
michael@0: #define BEV_UPCAST(b) EVUTIL_UPCAST((b), struct bufferevent_private, bev)
michael@0: 
michael@0: #ifdef _EVENT_DISABLE_THREAD_SUPPORT
michael@0: #define BEV_LOCK(b) _EVUTIL_NIL_STMT
michael@0: #define BEV_UNLOCK(b) _EVUTIL_NIL_STMT
michael@0: #else
michael@0: /** Internal: Grab the lock (if any) on a bufferevent */
michael@0: #define BEV_LOCK(b) do {						\
michael@0: 		struct bufferevent_private *locking =  BEV_UPCAST(b);	\
michael@0: 		EVLOCK_LOCK(locking->lock, 0);				\
michael@0: 	} while (0)
michael@0: 
michael@0: /** Internal: Release the lock (if any) on a bufferevent */
michael@0: #define BEV_UNLOCK(b) do {						\
michael@0: 		struct bufferevent_private *locking =  BEV_UPCAST(b);	\
michael@0: 		EVLOCK_UNLOCK(locking->lock, 0);			\
michael@0: 	} while (0)
michael@0: #endif
michael@0: 
michael@0: 
michael@0: /* ==== For rate-limiting. */
michael@0: 
michael@0: int _bufferevent_decrement_write_buckets(struct bufferevent_private *bev,
michael@0:     ev_ssize_t bytes);
michael@0: int _bufferevent_decrement_read_buckets(struct bufferevent_private *bev,
michael@0:     ev_ssize_t bytes);
michael@0: ev_ssize_t _bufferevent_get_read_max(struct bufferevent_private *bev);
michael@0: ev_ssize_t _bufferevent_get_write_max(struct bufferevent_private *bev);
michael@0: 
michael@0: #ifdef __cplusplus
michael@0: }
michael@0: #endif
michael@0: 
michael@0: 
michael@0: #endif /* _BUFFEREVENT_INTERNAL_H_ */