2025-01-22 17:22:38 +01:00

96 lines
4.3 KiB
C

/*
* libwebsockets - small server side websockets and web server implementation
*
* Copyright (C) 2010 - 2019 Andy Green <andy@warmcat.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
typedef struct lws_retry_bo {
const uint32_t *retry_ms_table; /* base delay in ms */
uint16_t retry_ms_table_count; /* entries in table */
uint16_t conceal_count; /* max retries to conceal */
uint16_t secs_since_valid_ping; /* idle before PING issued */
uint16_t secs_since_valid_hangup; /* idle before hangup conn */
uint8_t jitter_percent; /* % additional random jitter */
} lws_retry_bo_t;
#define LWS_RETRY_CONCEAL_ALWAYS (0xffff)
/**
* lws_retry_get_delay_ms() - get next delay from backoff table
*
* \param lws_context: the lws context (used for getting random)
* \param retry: the retry backoff table we are using, or NULL for default
* \param ctry: pointer to the try counter
* \param conceal: pointer to flag set to nonzero if the try should be concealed
* in terms of creating an error
*
* Increments *\p try and retruns the number of ms that should elapse before the
* next connection retry, according to the backoff table \p retry. *\p conceal is
* set if the number of tries is less than the backoff table conceal_count, or
* is zero if it exceeded it. This lets you conceal a certain number of retries
* before alerting the caller there is a problem.
*
* If \p retry is NULL, a default of 3s + (0..300ms jitter) is used. If it's
* non-NULL but jitter_percent is 0, the default of 30% jitter is retained.
*/
LWS_VISIBLE LWS_EXTERN unsigned int
lws_retry_get_delay_ms(struct lws_context *context, const lws_retry_bo_t *retry,
uint16_t *ctry, char *conceal);
/**
* lws_retry_sul_schedule() - schedule a sul according to the backoff table
*
* \param lws_context: the lws context (used for getting random)
* \param sul: pointer to the sul to schedule
* \param retry: the retry backoff table we are using, or NULL for default
* \param cb: the callback for when the sul schedule time arrives
* \param ctry: pointer to the try counter
*
* Helper that combines interpreting the retry table with scheduling a sul to
* the computed delay. If conceal is not set, it will not schedule the sul
* and just return 1. Otherwise the sul is scheduled and it returns 0.
*/
LWS_VISIBLE LWS_EXTERN int
lws_retry_sul_schedule(struct lws_context *context, int tid,
lws_sorted_usec_list_t *sul, const lws_retry_bo_t *retry,
sul_cb_t cb, uint16_t *ctry);
/**
* lws_retry_sul_schedule_retry_wsi() - retry sul schedule helper using wsi
*
* \param wsi: the wsi to set the hrtimer sul on to the next retry interval
* \param sul: pointer to the sul to schedule
* \param cb: the callback for when the sul schedule time arrives
* \param ctry: pointer to the try counter
*
* Helper that uses context, tid and retry policy from a wsi to call
* lws_retry_sul_schedule.
*
* Since a udp connection can have many writes in flight, the retry count and
* the sul used to track each thing that wants to be written have to be handled
* individually, not the wsi. But the retry policy and the other things can
* be filled in from the wsi conveniently.
*/
LWS_VISIBLE LWS_EXTERN int
lws_retry_sul_schedule_retry_wsi(struct lws *wsi, lws_sorted_usec_list_t *sul,
sul_cb_t cb, uint16_t *ctry);