Mercurial > dovecot > core-2.2
view src/anvil/penalty.c @ 22715:20415dd0b85a
dsync: Add per-mailbox sync lock that is always used.
Both importing and exporting gets the lock before they even sync the
mailbox. The lock is kept until the import/export finishes. This guarantees
that no matter how dsync is run, two dsyncs can't be working on the same
mailbox at the same time.
This lock is in addition to the optional per-user lock enabled by the -l
parameter. If the -l parameter is used, the same lock timeout is used for
the per-mailbox lock. Otherwise 30s timeout is used.
This should help to avoid email duplication when replication is enabled for
public namespaces, and maybe in some other rare situations as well.
author | Timo Sirainen <timo.sirainen@dovecot.fi> |
---|---|
date | Thu, 28 Dec 2017 14:10:23 +0200 |
parents | cb108f786fb4 |
children |
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/* Copyright (c) 2009-2018 Dovecot authors, see the included COPYING file */ /* The idea behind checksums is that the same username+password doesn't increase the penalty, because it's most likely a user with a misconfigured account. */ #include "lib.h" #include "ioloop.h" #include "hash.h" #include "str.h" #include "strescape.h" #include "llist.h" #include "ostream.h" #include "penalty.h" #include <time.h> #define PENALTY_DEFAULT_EXPIRE_SECS (60*60) #define PENALTY_CHECKSUM_SAVE_COUNT #define CHECKSUM_VALUE_COUNT 2 #define CHECKSUM_VALUE_PTR_COUNT 10 #define LAST_UPDATE_BITS 15 struct penalty_rec { /* ordered by last_update */ struct penalty_rec *prev, *next; char *ident; unsigned int last_penalty; unsigned int penalty:16; unsigned int last_update:LAST_UPDATE_BITS; /* last_penalty + n */ unsigned int checksum_is_pointer:1; /* we use value up to two different checksums. after that switch to pointer. */ union { unsigned int value[CHECKSUM_VALUE_COUNT]; unsigned int *value_ptr; } checksum; }; struct penalty { /* ident => penalty_rec */ HASH_TABLE(char *, struct penalty_rec *) hash; struct penalty_rec *oldest, *newest; unsigned int expire_secs; struct timeout *to; }; struct penalty *penalty_init(void) { struct penalty *penalty; penalty = i_new(struct penalty, 1); hash_table_create(&penalty->hash, default_pool, 0, str_hash, strcmp); penalty->expire_secs = PENALTY_DEFAULT_EXPIRE_SECS; return penalty; } static void penalty_rec_free(struct penalty *penalty, struct penalty_rec *rec) { DLLIST2_REMOVE(&penalty->oldest, &penalty->newest, rec); if (rec->checksum_is_pointer) i_free(rec->checksum.value_ptr); i_free(rec->ident); i_free(rec); } void penalty_deinit(struct penalty **_penalty) { struct penalty *penalty = *_penalty; *_penalty = NULL; while (penalty->oldest != NULL) penalty_rec_free(penalty, penalty->oldest); hash_table_destroy(&penalty->hash); if (penalty->to != NULL) timeout_remove(&penalty->to); i_free(penalty); } void penalty_set_expire_secs(struct penalty *penalty, unsigned int expire_secs) { penalty->expire_secs = expire_secs; } static bool penalty_bump_checksum(struct penalty_rec *rec, unsigned int checksum) { unsigned int *checksums; unsigned int i, count; if (!rec->checksum_is_pointer) { checksums = rec->checksum.value; count = CHECKSUM_VALUE_COUNT; } else { checksums = rec->checksum.value_ptr; count = CHECKSUM_VALUE_PTR_COUNT; } for (i = 0; i < count; i++) { if (checksums[i] == checksum) { if (i > 0) { memmove(checksums + 1, checksums, sizeof(checksums[0]) * i); checksums[0] = checksum; } return TRUE; } } return FALSE; } static void penalty_add_checksum(struct penalty_rec *rec, unsigned int checksum) { unsigned int *checksums; i_assert(checksum != 0); if (!rec->checksum_is_pointer) { if (rec->checksum.value[CHECKSUM_VALUE_COUNT-1] == 0) { memcpy(rec->checksum.value + 1, rec->checksum.value, sizeof(rec->checksum.value[0]) * (CHECKSUM_VALUE_COUNT-1)); rec->checksum.value[0] = checksum; return; } /* switch to using a pointer */ checksums = i_new(unsigned int, CHECKSUM_VALUE_PTR_COUNT); memcpy(checksums, rec->checksum.value, sizeof(checksums[0]) * CHECKSUM_VALUE_COUNT); rec->checksum.value_ptr = checksums; rec->checksum_is_pointer = TRUE; } memmove(rec->checksum.value_ptr + 1, rec->checksum.value_ptr, sizeof(rec->checksum.value_ptr[0]) * (CHECKSUM_VALUE_PTR_COUNT-1)); rec->checksum.value_ptr[0] = checksum; } unsigned int penalty_get(struct penalty *penalty, const char *ident, time_t *last_penalty_r) { struct penalty_rec *rec; rec = hash_table_lookup(penalty->hash, ident); if (rec == NULL) { *last_penalty_r = 0; return 0; } *last_penalty_r = rec->last_penalty; return rec->penalty; } static void penalty_timeout(struct penalty *penalty) { struct penalty_rec *rec; time_t rec_last_update, expire_time; unsigned int diff; timeout_remove(&penalty->to); expire_time = ioloop_time - penalty->expire_secs; while (penalty->oldest != NULL) { rec = penalty->oldest; rec_last_update = rec->last_penalty + rec->last_update; if (rec_last_update > expire_time) { diff = rec_last_update - expire_time; penalty->to = timeout_add(diff * 1000, penalty_timeout, penalty); break; } hash_table_remove(penalty->hash, rec->ident); penalty_rec_free(penalty, rec); } } void penalty_inc(struct penalty *penalty, const char *ident, unsigned int checksum, unsigned int value) { struct penalty_rec *rec; time_t diff; i_assert(value > 0 || checksum == 0); i_assert(value <= INT_MAX); rec = hash_table_lookup(penalty->hash, ident); if (rec == NULL) { rec = i_new(struct penalty_rec, 1); rec->ident = i_strdup(ident); hash_table_insert(penalty->hash, rec->ident, rec); } else { DLLIST2_REMOVE(&penalty->oldest, &penalty->newest, rec); } if (checksum == 0) { rec->penalty = value; rec->last_penalty = ioloop_time; } else { if (penalty_bump_checksum(rec, checksum)) rec->penalty = value - 1; else { penalty_add_checksum(rec, checksum); rec->penalty = value; rec->last_penalty = ioloop_time; } } diff = ioloop_time - rec->last_penalty; if (diff >= (1 << LAST_UPDATE_BITS)) { rec->last_update = (1 << LAST_UPDATE_BITS) - 1; rec->last_penalty = ioloop_time - rec->last_update; } else { rec->last_update = diff; } DLLIST2_APPEND(&penalty->oldest, &penalty->newest, rec); if (penalty->to == NULL) { penalty->to = timeout_add(penalty->expire_secs * 1000, penalty_timeout, penalty); } } bool penalty_has_checksum(struct penalty *penalty, const char *ident, unsigned int checksum) { struct penalty_rec *rec; const unsigned int *checksums; unsigned int i, count; rec = hash_table_lookup(penalty->hash, ident); if (rec == NULL) return FALSE; if (!rec->checksum_is_pointer) { checksums = rec->checksum.value; count = CHECKSUM_VALUE_COUNT; } else { checksums = rec->checksum.value_ptr; count = CHECKSUM_VALUE_PTR_COUNT; } for (i = 0; i < count; i++) { if (checksums[i] == checksum) return TRUE; } return FALSE; } void penalty_dump(struct penalty *penalty, struct ostream *output) { const struct penalty_rec *rec; string_t *str = t_str_new(256); for (rec = penalty->oldest; rec != NULL; rec = rec->next) { str_truncate(str, 0); str_append_tabescaped(str, rec->ident); str_printfa(str, "\t%u\t%u\t%u\n", rec->penalty, rec->last_penalty, rec->last_penalty + rec->last_update); if (o_stream_send(output, str_data(str), str_len(str)) < 0) break; } o_stream_nsend(output, "\n", 1); }