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Diffstat (limited to 'src/feature/dirclient/download_status_st.h')
| -rw-r--r-- | src/feature/dirclient/download_status_st.h | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/src/feature/dirclient/download_status_st.h b/src/feature/dirclient/download_status_st.h new file mode 100644 index 0000000000..3f18f754a1 --- /dev/null +++ b/src/feature/dirclient/download_status_st.h @@ -0,0 +1,65 @@ +/* Copyright (c) 2001 Matej Pfajfar. + * Copyright (c) 2001-2004, Roger Dingledine. + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. + * Copyright (c) 2007-2018, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +#ifndef DOWNLOAD_STATUS_ST_H +#define DOWNLOAD_STATUS_ST_H + +/** Information about our plans for retrying downloads for a downloadable + * directory object. + * Each type of downloadable directory object has a corresponding retry + * <b>schedule</b>, which can be different depending on whether the object is + * being downloaded from an authority or a mirror (<b>want_authority</b>). + * <b>next_attempt_at</b> contains the next time we will attempt to download + * the object. + * For schedules that <b>increment_on</b> failure, <b>n_download_failures</b> + * is used to determine the position in the schedule. (Each schedule is a + * smartlist of integer delays, parsed from a CSV option.) Every time a + * connection attempt fails, <b>n_download_failures</b> is incremented, + * the new delay value is looked up from the schedule, and + * <b>next_attempt_at</b> is set delay seconds from the time the previous + * connection failed. Therefore, at most one failure-based connection can be + * in progress for each download_status_t. + * For schedules that <b>increment_on</b> attempt, <b>n_download_attempts</b> + * is used to determine the position in the schedule. Every time a + * connection attempt is made, <b>n_download_attempts</b> is incremented, + * the new delay value is looked up from the schedule, and + * <b>next_attempt_at</b> is set delay seconds from the time the previous + * connection was attempted. Therefore, multiple concurrent attempted-based + * connections can be in progress for each download_status_t. + * After an object is successfully downloaded, any other concurrent connections + * are terminated. A new schedule which starts at position 0 is used for + * subsequent downloads of the same object. + */ +struct download_status_t { + time_t next_attempt_at; /**< When should we try downloading this object + * again? */ + uint8_t n_download_failures; /**< Number of failed downloads of the most + * recent object, since the last success. */ + uint8_t n_download_attempts; /**< Number of (potentially concurrent) attempts + * to download the most recent object, since + * the last success. */ + download_schedule_bitfield_t schedule : 8; /**< What kind of object is being + * downloaded? This determines the + * schedule used for the download. + */ + download_want_authority_bitfield_t want_authority : 1; /**< Is the download + * happening from an authority + * or a mirror? This determines + * the schedule used for the + * download. */ + download_schedule_increment_bitfield_t increment_on : 1; /**< does this + * schedule increment on each attempt, + * or after each failure? */ + uint8_t last_backoff_position; /**< number of attempts/failures, depending + * on increment_on, when we last recalculated + * the delay. Only updated if backoff + * == 1. */ + int last_delay_used; /**< last delay used for random exponential backoff; + * only updated if backoff == 1 */ +}; + +#endif + |