From: Timo Sirainen Date: Sat, 25 Nov 2017 08:01:31 +0000 (+0200) Subject: director: Don't send USERs in handshake that were already sent between handshake X-Git-Tag: 2.2.34~213 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b0d1558c88147d3ec3d18ba0ee7fa18e11c619d0;p=thirdparty%2Fdovecot%2Fcore.git director: Don't send USERs in handshake that were already sent between handshake If the user was refreshed since the handshake was started, it means that the same user was already sent to the other side (added to the stream immediately after it was received/handled). There's no need to send it again. This fixes a potentally infinite handshake when users are rapidly changing and the handshake iterator never sees the end of the list. (Each refreshed user is moved to the end of the list, so handshaking can keep sending the same user over and over again.) --- diff --git a/src/director/director-connection.c b/src/director/director-connection.c index 9a176ea982..1063ec24a4 100644 --- a/src/director/director-connection.c +++ b/src/director/director-connection.c @@ -2255,7 +2255,16 @@ static void director_finish_sending_handshake(struct director_connection *conn) director_connection_send_hosts(conn); i_assert(conn->user_iter == NULL); - conn->user_iter = director_iterate_users_init(conn->dir); + /* Iterate only through users that aren't refreshed since the + iteration started. The refreshed users will already be sent as + regular USER updates, so they don't need to be sent again. + + We especially don't want to send these users again, because + otherwise in a rapidly changing director we might never end up + sending all the users when they constantly keep being added to the + end of the list. (The iteration lists users in order from older to + newer.) */ + conn->user_iter = director_iterate_users_init(conn->dir, TRUE); if (director_connection_send_users(conn) == 0) o_stream_set_flush_pending(conn->output, TRUE); diff --git a/src/director/director.c b/src/director/director.c index 30749a41d1..9f6a6d5c21 100644 --- a/src/director/director.c +++ b/src/director/director.c @@ -1520,12 +1520,15 @@ struct director_user_iter { struct director *dir; unsigned int tag_idx; struct user_directory_iter *user_iter; + bool iter_until_current_tail; }; -struct director_user_iter *director_iterate_users_init(struct director *dir) +struct director_user_iter * +director_iterate_users_init(struct director *dir, bool iter_until_current_tail) { struct director_user_iter *iter = i_new(struct director_user_iter, 1); iter->dir = dir; + iter->iter_until_current_tail = iter_until_current_tail; return iter; } @@ -1541,7 +1544,8 @@ struct user *director_iterate_users_next(struct director_user_iter *iter) if (iter->tag_idx >= array_count(tags)) return NULL; struct mail_tag *const *tagp = array_idx(tags, iter->tag_idx); - iter->user_iter = user_directory_iter_init((*tagp)->users); + iter->user_iter = user_directory_iter_init((*tagp)->users, + iter->iter_until_current_tail); } user = user_directory_iter_next(iter->user_iter); if (user == NULL) { diff --git a/src/director/director.h b/src/director/director.h index 2f7acd4ccb..812ac0d717 100644 --- a/src/director/director.h +++ b/src/director/director.h @@ -266,7 +266,8 @@ void directors_deinit(void); void dir_debug(const char *fmt, ...) ATTR_FORMAT(1, 2); -struct director_user_iter *director_iterate_users_init(struct director *dir); +struct director_user_iter * +director_iterate_users_init(struct director *dir, bool iter_until_current_tail); struct user *director_iterate_users_next(struct director_user_iter *iter); void director_iterate_users_deinit(struct director_user_iter **_iter); diff --git a/src/director/doveadm-connection.c b/src/director/doveadm-connection.c index a8cfe02e44..baa0a34f54 100644 --- a/src/director/doveadm-connection.c +++ b/src/director/doveadm-connection.c @@ -522,7 +522,7 @@ director_host_reset_users(struct director_reset_cmd *cmd, director_connection_cork(dir->right); if (cmd->iter == NULL) { - cmd->iter = director_iterate_users_init(dir); + cmd->iter = director_iterate_users_init(dir, FALSE); cmd->users_killed = FALSE; } @@ -715,7 +715,7 @@ doveadm_cmd_user_list(struct doveadm_connection *conn, const char *const *args) ip.family = 0; } - iter = director_iterate_users_init(conn->dir); + iter = director_iterate_users_init(conn->dir, FALSE); while ((user = director_iterate_users_next(iter)) != NULL) { if (ip.family == 0 || net_ip_compare(&ip, &user->host->ip)) T_BEGIN { diff --git a/src/director/test-user-directory.c b/src/director/test-user-directory.c index ec26c66368..87e2eb2086 100644 --- a/src/director/test-user-directory.c +++ b/src/director/test-user-directory.c @@ -19,7 +19,7 @@ verify_user_directory(struct user_directory *dir, unsigned int user_count) struct user *user, *prev = NULL; unsigned int prev_stamp = 0, iter_count = 0; - iter = user_directory_iter_init(dir); + iter = user_directory_iter_init(dir, FALSE); while ((user = user_directory_iter_next(iter)) != NULL) { test_assert(prev_stamp <= user->timestamp); test_assert(user->prev == prev); diff --git a/src/director/user-directory.c b/src/director/user-directory.c index 05b05bb27f..f0fca7f35b 100644 --- a/src/director/user-directory.c +++ b/src/director/user-directory.c @@ -17,7 +17,7 @@ struct user_directory_iter { struct user_directory *dir; - struct user *pos; + struct user *pos, *stop_after_tail; }; struct user_directory { @@ -46,6 +46,10 @@ static void user_move_iters(struct user_directory *dir, struct user *user) array_foreach(&dir->iters, iterp) { if ((*iterp)->pos == user) (*iterp)->pos = user->next; + if ((*iterp)->stop_after_tail == user) { + (*iterp)->stop_after_tail = + user->prev != NULL ? user->prev : user->next; + } } } @@ -291,13 +295,15 @@ void user_directory_deinit(struct user_directory **_dir) } struct user_directory_iter * -user_directory_iter_init(struct user_directory *dir) +user_directory_iter_init(struct user_directory *dir, + bool iter_until_current_tail) { struct user_directory_iter *iter; iter = i_new(struct user_directory_iter, 1); iter->dir = dir; iter->pos = dir->head; + iter->stop_after_tail = iter_until_current_tail ? dir->tail : NULL; array_append(&dir->iters, &iter, 1); user_directory_drop_expired(dir); return iter; @@ -312,6 +318,10 @@ struct user *user_directory_iter_next(struct user_directory_iter *iter) return NULL; iter->pos = user->next; + if (user == iter->stop_after_tail) { + /* this is the last user we want to iterate */ + iter->pos = NULL; + } return user; } diff --git a/src/director/user-directory.h b/src/director/user-directory.h index 5b46330a66..9a7ed49584 100644 --- a/src/director/user-directory.h +++ b/src/director/user-directory.h @@ -62,10 +62,15 @@ bool user_directory_user_is_near_expiring(struct user_directory *dir, struct user *user); /* Iterate through users in the directory. It's safe to modify user directory - while iterators are running. The moved/removed users will just be skipped - over. */ + while iterators are running. The removed users will just be skipped over. + Users that are refreshed (= moved to end of list) may be processed twice. + + Using iter_until_current_tail=TRUE causes the iterator to not iterate + through any users that were added/refreshed since the iteration began. + Note that this may skip some users entirely. */ struct user_directory_iter * -user_directory_iter_init(struct user_directory *dir); +user_directory_iter_init(struct user_directory *dir, + bool iter_until_current_tail); struct user *user_directory_iter_next(struct user_directory_iter *iter); void user_directory_iter_deinit(struct user_directory_iter **iter);