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Diffstat (limited to 'sntp/libevent/bufferevent-internal.h')
| -rw-r--r-- | sntp/libevent/bufferevent-internal.h | 450 |
1 files changed, 450 insertions, 0 deletions
diff --git a/sntp/libevent/bufferevent-internal.h b/sntp/libevent/bufferevent-internal.h new file mode 100644 index 000000000000..134bb337521c --- /dev/null +++ b/sntp/libevent/bufferevent-internal.h @@ -0,0 +1,450 @@ +/* + * Copyright (c) 2008-2012 Niels Provos and Nick Mathewson + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ +#ifndef BUFFEREVENT_INTERNAL_H_INCLUDED_ +#define BUFFEREVENT_INTERNAL_H_INCLUDED_ + +#ifdef __cplusplus +extern "C" { +#endif + +#include "event2/event-config.h" +#include "event2/event_struct.h" +#include "evconfig-private.h" +#include "event2/util.h" +#include "defer-internal.h" +#include "evthread-internal.h" +#include "event2/thread.h" +#include "ratelim-internal.h" +#include "event2/bufferevent_struct.h" + +/* These flags are reasons that we might be declining to actually enable + reading or writing on a bufferevent. + */ + +/* On a all bufferevents, for reading: used when we have read up to the + watermark value. + + On a filtering bufferevent, for writing: used when the underlying + bufferevent's write buffer has been filled up to its watermark + value. +*/ +#define BEV_SUSPEND_WM 0x01 +/* On a base bufferevent: when we have emptied a bandwidth buckets */ +#define BEV_SUSPEND_BW 0x02 +/* On a base bufferevent: when we have emptied the group's bandwidth bucket. */ +#define BEV_SUSPEND_BW_GROUP 0x04 +/* On a socket bufferevent: can't do any operations while we're waiting for + * name lookup to finish. */ +#define BEV_SUSPEND_LOOKUP 0x08 +/* On a base bufferevent, for reading: used when a filter has choked this + * (underlying) bufferevent because it has stopped reading from it. */ +#define BEV_SUSPEND_FILT_READ 0x10 + +typedef ev_uint16_t bufferevent_suspend_flags; + +struct bufferevent_rate_limit_group { + /** List of all members in the group */ + LIST_HEAD(rlim_group_member_list, bufferevent_private) members; + /** Current limits for the group. */ + struct ev_token_bucket rate_limit; + struct ev_token_bucket_cfg rate_limit_cfg; + + /** True iff we don't want to read from any member of the group.until + * the token bucket refills. */ + unsigned read_suspended : 1; + /** True iff we don't want to write from any member of the group.until + * the token bucket refills. */ + unsigned write_suspended : 1; + /** True iff we were unable to suspend one of the bufferevents in the + * group for reading the last time we tried, and we should try + * again. */ + unsigned pending_unsuspend_read : 1; + /** True iff we were unable to suspend one of the bufferevents in the + * group for writing the last time we tried, and we should try + * again. */ + unsigned pending_unsuspend_write : 1; + + /*@{*/ + /** Total number of bytes read or written in this group since last + * reset. */ + ev_uint64_t total_read; + ev_uint64_t total_written; + /*@}*/ + + /** The number of bufferevents in the group. */ + int n_members; + + /** The smallest number of bytes that any member of the group should + * be limited to read or write at a time. */ + ev_ssize_t min_share; + ev_ssize_t configured_min_share; + + /** Timeout event that goes off once a tick, when the bucket is ready + * to refill. */ + struct event master_refill_event; + + /** Seed for weak random number generator. Protected by 'lock' */ + struct evutil_weakrand_state weakrand_seed; + + /** Lock to protect the members of this group. This lock should nest + * within every bufferevent lock: if you are holding this lock, do + * not assume you can lock another bufferevent. */ + void *lock; +}; + +/** Fields for rate-limiting a single bufferevent. */ +struct bufferevent_rate_limit { + /* Linked-list elements for storing this bufferevent_private in a + * group. + * + * Note that this field is supposed to be protected by the group + * lock */ + LIST_ENTRY(bufferevent_private) next_in_group; + /** The rate-limiting group for this bufferevent, or NULL if it is + * only rate-limited on its own. */ + struct bufferevent_rate_limit_group *group; + + /* This bufferevent's current limits. */ + struct ev_token_bucket limit; + /* Pointer to the rate-limit configuration for this bufferevent. + * Can be shared. XXX reference-count this? */ + struct ev_token_bucket_cfg *cfg; + + /* Timeout event used when one this bufferevent's buckets are + * empty. */ + struct event refill_bucket_event; +}; + +/** Parts of the bufferevent structure that are shared among all bufferevent + * types, but not exposed in bufferevent_struct.h. */ +struct bufferevent_private { + /** The underlying bufferevent structure. */ + struct bufferevent bev; + + /** Evbuffer callback to enforce watermarks on input. */ + struct evbuffer_cb_entry *read_watermarks_cb; + + /** If set, we should free the lock when we free the bufferevent. */ + unsigned own_lock : 1; + + /** Flag: set if we have deferred callbacks and a read callback is + * pending. */ + unsigned readcb_pending : 1; + /** Flag: set if we have deferred callbacks and a write callback is + * pending. */ + unsigned writecb_pending : 1; + /** Flag: set if we are currently busy connecting. */ + unsigned connecting : 1; + /** Flag: set if a connect failed prematurely; this is a hack for + * getting around the bufferevent abstraction. */ + unsigned connection_refused : 1; + /** Set to the events pending if we have deferred callbacks and + * an events callback is pending. */ + short eventcb_pending; + + /** If set, read is suspended until one or more conditions are over. + * The actual value here is a bitfield of those conditions; see the + * BEV_SUSPEND_* flags above. */ + bufferevent_suspend_flags read_suspended; + + /** If set, writing is suspended until one or more conditions are over. + * The actual value here is a bitfield of those conditions; see the + * BEV_SUSPEND_* flags above. */ + bufferevent_suspend_flags write_suspended; + + /** Set to the current socket errno if we have deferred callbacks and + * an events callback is pending. */ + int errno_pending; + + /** The DNS error code for bufferevent_socket_connect_hostname */ + int dns_error; + + /** Used to implement deferred callbacks */ + struct event_callback deferred; + + /** The options this bufferevent was constructed with */ + enum bufferevent_options options; + + /** Current reference count for this bufferevent. */ + int refcnt; + + /** Lock for this bufferevent. Shared by the inbuf and the outbuf. + * If NULL, locking is disabled. */ + void *lock; + + /** No matter how big our bucket gets, don't try to read more than this + * much in a single read operation. */ + ev_ssize_t max_single_read; + + /** No matter how big our bucket gets, don't try to write more than this + * much in a single write operation. */ + ev_ssize_t max_single_write; + + /** Rate-limiting information for this bufferevent */ + struct bufferevent_rate_limit *rate_limiting; +}; + +/** Possible operations for a control callback. */ +enum bufferevent_ctrl_op { + BEV_CTRL_SET_FD, + BEV_CTRL_GET_FD, + BEV_CTRL_GET_UNDERLYING, + BEV_CTRL_CANCEL_ALL +}; + +/** Possible data types for a control callback */ +union bufferevent_ctrl_data { + void *ptr; + evutil_socket_t fd; +}; + +/** + Implementation table for a bufferevent: holds function pointers and other + information to make the various bufferevent types work. +*/ +struct bufferevent_ops { + /** The name of the bufferevent's type. */ + const char *type; + /** At what offset into the implementation type will we find a + bufferevent structure? + + Example: if the type is implemented as + struct bufferevent_x { + int extra_data; + struct bufferevent bev; + } + then mem_offset should be offsetof(struct bufferevent_x, bev) + */ + off_t mem_offset; + + /** Enables one or more of EV_READ|EV_WRITE on a bufferevent. Does + not need to adjust the 'enabled' field. Returns 0 on success, -1 + on failure. + */ + int (*enable)(struct bufferevent *, short); + + /** Disables one or more of EV_READ|EV_WRITE on a bufferevent. Does + not need to adjust the 'enabled' field. Returns 0 on success, -1 + on failure. + */ + int (*disable)(struct bufferevent *, short); + + /** Detatches the bufferevent from related data structures. Called as + * soon as its reference count reaches 0. */ + void (*unlink)(struct bufferevent *); + + /** Free any storage and deallocate any extra data or structures used + in this implementation. Called when the bufferevent is + finalized. + */ + void (*destruct)(struct bufferevent *); + + /** Called when the timeouts on the bufferevent have changed.*/ + int (*adj_timeouts)(struct bufferevent *); + + /** Called to flush data. */ + int (*flush)(struct bufferevent *, short, enum bufferevent_flush_mode); + + /** Called to access miscellaneous fields. */ + int (*ctrl)(struct bufferevent *, enum bufferevent_ctrl_op, union bufferevent_ctrl_data *); + +}; + +extern const struct bufferevent_ops bufferevent_ops_socket; +extern const struct bufferevent_ops bufferevent_ops_filter; +extern const struct bufferevent_ops bufferevent_ops_pair; + +#define BEV_IS_SOCKET(bevp) ((bevp)->be_ops == &bufferevent_ops_socket) +#define BEV_IS_FILTER(bevp) ((bevp)->be_ops == &bufferevent_ops_filter) +#define BEV_IS_PAIR(bevp) ((bevp)->be_ops == &bufferevent_ops_pair) + +#ifdef _WIN32 +extern const struct bufferevent_ops bufferevent_ops_async; +#define BEV_IS_ASYNC(bevp) ((bevp)->be_ops == &bufferevent_ops_async) +#else +#define BEV_IS_ASYNC(bevp) 0 +#endif + +/** Initialize the shared parts of a bufferevent. */ +int bufferevent_init_common_(struct bufferevent_private *, struct event_base *, const struct bufferevent_ops *, enum bufferevent_options options); + +/** For internal use: temporarily stop all reads on bufev, until the conditions + * in 'what' are over. */ +void bufferevent_suspend_read_(struct bufferevent *bufev, bufferevent_suspend_flags what); +/** For internal use: clear the conditions 'what' on bufev, and re-enable + * reading if there are no conditions left. */ +void bufferevent_unsuspend_read_(struct bufferevent *bufev, bufferevent_suspend_flags what); + +/** For internal use: temporarily stop all writes on bufev, until the conditions + * in 'what' are over. */ +void bufferevent_suspend_write_(struct bufferevent *bufev, bufferevent_suspend_flags what); +/** For internal use: clear the conditions 'what' on bufev, and re-enable + * writing if there are no conditions left. */ +void bufferevent_unsuspend_write_(struct bufferevent *bufev, bufferevent_suspend_flags what); + +#define bufferevent_wm_suspend_read(b) \ + bufferevent_suspend_read_((b), BEV_SUSPEND_WM) +#define bufferevent_wm_unsuspend_read(b) \ + bufferevent_unsuspend_read_((b), BEV_SUSPEND_WM) + +/* + Disable a bufferevent. Equivalent to bufferevent_disable(), but + first resets 'connecting' flag to force EV_WRITE down for sure. + + XXXX this method will go away in the future; try not to add new users. + See comment in evhttp_connection_reset_() for discussion. + + @param bufev the bufferevent to be disabled + @param event any combination of EV_READ | EV_WRITE. + @return 0 if successful, or -1 if an error occurred + @see bufferevent_disable() + */ +int bufferevent_disable_hard_(struct bufferevent *bufev, short event); + +/** Internal: Set up locking on a bufferevent. If lock is set, use it. + * Otherwise, use a new lock. */ +int bufferevent_enable_locking_(struct bufferevent *bufev, void *lock); +/** Internal: Increment the reference count on bufev. */ +void bufferevent_incref_(struct bufferevent *bufev); +/** Internal: Lock bufev and increase its reference count. + * unlocking it otherwise. */ +void bufferevent_incref_and_lock_(struct bufferevent *bufev); +/** Internal: Decrement the reference count on bufev. Returns 1 if it freed + * the bufferevent.*/ +int bufferevent_decref_(struct bufferevent *bufev); +/** Internal: Drop the reference count on bufev, freeing as necessary, and + * unlocking it otherwise. Returns 1 if it freed the bufferevent. */ +int bufferevent_decref_and_unlock_(struct bufferevent *bufev); + +/** Internal: If callbacks are deferred and we have a read callback, schedule + * a readcb. Otherwise just run the readcb. Ignores watermarks. */ +void bufferevent_run_readcb_(struct bufferevent *bufev, int options); +/** Internal: If callbacks are deferred and we have a write callback, schedule + * a writecb. Otherwise just run the writecb. Ignores watermarks. */ +void bufferevent_run_writecb_(struct bufferevent *bufev, int options); +/** Internal: If callbacks are deferred and we have an eventcb, schedule + * it to run with events "what". Otherwise just run the eventcb. + * See bufferevent_trigger_event for meaning of "options". */ +void bufferevent_run_eventcb_(struct bufferevent *bufev, short what, int options); + +/** Internal: Run or schedule (if deferred or options contain + * BEV_TRIG_DEFER_CALLBACKS) I/O callbacks specified in iotype. + * Must already hold the bufev lock. Honors watermarks unless + * BEV_TRIG_IGNORE_WATERMARKS is in options. */ +static inline void bufferevent_trigger_nolock_(struct bufferevent *bufev, short iotype, int options); + +/* Making this inline since all of the common-case calls to this function in + * libevent use constant arguments. */ +static inline void +bufferevent_trigger_nolock_(struct bufferevent *bufev, short iotype, int options) +{ + if ((iotype & EV_READ) && ((options & BEV_TRIG_IGNORE_WATERMARKS) || + evbuffer_get_length(bufev->input) >= bufev->wm_read.low)) + bufferevent_run_readcb_(bufev, options); + if ((iotype & EV_WRITE) && ((options & BEV_TRIG_IGNORE_WATERMARKS) || + evbuffer_get_length(bufev->output) <= bufev->wm_write.low)) + bufferevent_run_writecb_(bufev, options); +} + +/** Internal: Add the event 'ev' with timeout tv, unless tv is set to 0, in + * which case add ev with no timeout. */ +int bufferevent_add_event_(struct event *ev, const struct timeval *tv); + +/* ========= + * These next functions implement timeouts for bufferevents that aren't doing + * anything else with ev_read and ev_write, to handle timeouts. + * ========= */ +/** Internal use: Set up the ev_read and ev_write callbacks so that + * the other "generic_timeout" functions will work on it. Call this from + * the constructor function. */ +void bufferevent_init_generic_timeout_cbs_(struct bufferevent *bev); +/** Internal use: Add or delete the generic timeout events as appropriate. + * (If an event is enabled and a timeout is set, we add the event. Otherwise + * we delete it.) Call this from anything that changes the timeout values, + * that enabled EV_READ or EV_WRITE, or that disables EV_READ or EV_WRITE. */ +int bufferevent_generic_adj_timeouts_(struct bufferevent *bev); + +enum bufferevent_options bufferevent_get_options_(struct bufferevent *bev); + +/** Internal use: We have just successfully read data into an inbuf, so + * reset the read timeout (if any). */ +#define BEV_RESET_GENERIC_READ_TIMEOUT(bev) \ + do { \ + if (evutil_timerisset(&(bev)->timeout_read)) \ + event_add(&(bev)->ev_read, &(bev)->timeout_read); \ + } while (0) +/** Internal use: We have just successfully written data from an inbuf, so + * reset the read timeout (if any). */ +#define BEV_RESET_GENERIC_WRITE_TIMEOUT(bev) \ + do { \ + if (evutil_timerisset(&(bev)->timeout_write)) \ + event_add(&(bev)->ev_write, &(bev)->timeout_write); \ + } while (0) +#define BEV_DEL_GENERIC_READ_TIMEOUT(bev) \ + event_del(&(bev)->ev_read) +#define BEV_DEL_GENERIC_WRITE_TIMEOUT(bev) \ + event_del(&(bev)->ev_write) + + +/** Internal: Given a bufferevent, return its corresponding + * bufferevent_private. */ +#define BEV_UPCAST(b) EVUTIL_UPCAST((b), struct bufferevent_private, bev) + +#ifdef EVENT__DISABLE_THREAD_SUPPORT +#define BEV_LOCK(b) EVUTIL_NIL_STMT_ +#define BEV_UNLOCK(b) EVUTIL_NIL_STMT_ +#else +/** Internal: Grab the lock (if any) on a bufferevent */ +#define BEV_LOCK(b) do { \ + struct bufferevent_private *locking = BEV_UPCAST(b); \ + EVLOCK_LOCK(locking->lock, 0); \ + } while (0) + +/** Internal: Release the lock (if any) on a bufferevent */ +#define BEV_UNLOCK(b) do { \ + struct bufferevent_private *locking = BEV_UPCAST(b); \ + EVLOCK_UNLOCK(locking->lock, 0); \ + } while (0) +#endif + + +/* ==== For rate-limiting. */ + +int bufferevent_decrement_write_buckets_(struct bufferevent_private *bev, + ev_ssize_t bytes); +int bufferevent_decrement_read_buckets_(struct bufferevent_private *bev, + ev_ssize_t bytes); +ev_ssize_t bufferevent_get_read_max_(struct bufferevent_private *bev); +ev_ssize_t bufferevent_get_write_max_(struct bufferevent_private *bev); + +int bufferevent_ratelim_init_(struct bufferevent_private *bev); + +#ifdef __cplusplus +} +#endif + + +#endif /* BUFFEREVENT_INTERNAL_H_INCLUDED_ */ |