1 /* 2 * libwebsockets - small server side websockets and web server implementation 3 * 4 * Copyright (C) 2010 - 2019 Andy Green <andy@warmcat.com> 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a copy 7 * of this software and associated documentation files (the "Software"), to 8 * deal in the Software without restriction, including without limitation the 9 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or 10 * sell copies of the Software, and to permit persons to whom the Software is 11 * furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 22 * IN THE SOFTWARE. 23 */ 24 25 typedef struct lws_retry_bo { 26 const uint32_t *retry_ms_table; /* base delay in ms */ 27 uint16_t retry_ms_table_count; /* entries in table */ 28 uint16_t conceal_count; /* max retries to conceal */ 29 uint16_t secs_since_valid_ping; /* idle before PING issued */ 30 uint16_t secs_since_valid_hangup; /* idle before hangup conn */ 31 uint8_t jitter_percent; /* % additional random jitter */ 32 } lws_retry_bo_t; 33 34 #define LWS_RETRY_CONCEAL_ALWAYS (0xffff) 35 36 /** 37 * lws_retry_get_delay_ms() - get next delay from backoff table 38 * 39 * \param lws_context: the lws context (used for getting random) 40 * \param retry: the retry backoff table we are using, or NULL for default 41 * \param ctry: pointer to the try counter 42 * \param conceal: pointer to flag set to nonzero if the try should be concealed 43 * in terms of creating an error 44 * 45 * Increments *\p try and retruns the number of ms that should elapse before the 46 * next connection retry, according to the backoff table \p retry. *\p conceal is 47 * set if the number of tries is less than the backoff table conceal_count, or 48 * is zero if it exceeded it. This lets you conceal a certain number of retries 49 * before alerting the caller there is a problem. 50 * 51 * If \p retry is NULL, a default of 3s + (0..300ms jitter) is used. If it's 52 * non-NULL but jitter_percent is 0, the default of 30% jitter is retained. 53 */ 54 55 LWS_VISIBLE LWS_EXTERN unsigned int 56 lws_retry_get_delay_ms(struct lws_context *context, const lws_retry_bo_t *retry, 57 uint16_t *ctry, char *conceal); 58 59 /** 60 * lws_retry_sul_schedule() - schedule a sul according to the backoff table 61 * 62 * \param lws_context: the lws context (used for getting random) 63 * \param sul: pointer to the sul to schedule 64 * \param retry: the retry backoff table we are using, or NULL for default 65 * \param cb: the callback for when the sul schedule time arrives 66 * \param ctry: pointer to the try counter 67 * 68 * Helper that combines interpreting the retry table with scheduling a sul to 69 * the computed delay. If conceal is not set, it will not schedule the sul 70 * and just return 1. Otherwise the sul is scheduled and it returns 0. 71 */ 72 LWS_VISIBLE LWS_EXTERN int 73 lws_retry_sul_schedule(struct lws_context *context, int tid, 74 lws_sorted_usec_list_t *sul, const lws_retry_bo_t *retry, 75 sul_cb_t cb, uint16_t *ctry); 76 77 /** 78 * lws_retry_sul_schedule_retry_wsi() - retry sul schedule helper using wsi 79 * 80 * \param wsi: the wsi to set the hrtimer sul on to the next retry interval 81 * \param sul: pointer to the sul to schedule 82 * \param cb: the callback for when the sul schedule time arrives 83 * \param ctry: pointer to the try counter 84 * 85 * Helper that uses context, tid and retry policy from a wsi to call 86 * lws_retry_sul_schedule. 87 * 88 * Since a udp connection can have many writes in flight, the retry count and 89 * the sul used to track each thing that wants to be written have to be handled 90 * individually, not the wsi. But the retry policy and the other things can 91 * be filled in from the wsi conveniently. 92 */ 93 LWS_VISIBLE LWS_EXTERN int 94 lws_retry_sul_schedule_retry_wsi(struct lws *wsi, lws_sorted_usec_list_t *sul, 95 sul_cb_t cb, uint16_t *ctry); 96