src/director/doveadm-connection.c

/* Copyright (c) 2010-2018 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "ioloop.h"
#include "net.h"
#include "istream.h"
#include "ostream.h"
#include "array.h"
#include "str.h"
#include "strescape.h"
#include "llist.h"
#include "time-util.h"
#include "master-service.h"
#include "user-directory.h"
#include "mail-host.h"
#include "director.h"
#include "director-host.h"
#include "director-request.h"
#include "director-connection.h"
#include "doveadm-connection.h"

#include <unistd.h>

#define DOVEADM_PROTOCOL_VERSION_MAJOR 1
#define DOVEADM_HANDSHAKE "VERSION\tdirector-doveadm\t1\t0\n"

#define MAX_VALID_VHOST_COUNT 1000

#define DOVEADM_CONNECTION_RING_SYNC_TIMEOUT_MSECS (30*1000)

enum doveadm_director_cmd_ret {
    DOVEADM_DIRECTOR_CMD_RET_FAIL = -1,
    DOVEADM_DIRECTOR_CMD_RET_UNFINISHED = 0,
    DOVEADM_DIRECTOR_CMD_RET_OK = 1,
    DOVEADM_DIRECTOR_CMD_RET_RING_SYNC_OK,
};

enum doveadm_director_cmd_flag {
    DOVEADM_DIRECTOR_CMD_FLAG_PRE_RING_SYNC = 0x01,
};

typedef void
doveadm_connection_ring_sync_callback_t(struct doveadm_connection *);

struct director_reset_cmd {
    struct director_reset_cmd *prev, *next;

    struct director *dir;
    struct doveadm_connection *_conn;
    struct timeval start_time;

    struct director_user_iter *iter;
    unsigned int host_start_idx, host_idx, hosts_count;
    unsigned int max_moving_users;
    unsigned int reset_count;
    bool users_killed;
};

struct director_kick_cmd {
    struct director_kick_cmd *prev, *next;

    struct doveadm_connection *_conn;
    struct director *dir;
    char *mask, *field, *value;
    bool alt:1;
};

struct doveadm_connection {
    struct doveadm_connection *prev, *next;

    int fd;
    struct io *io;
    struct istream *input;
    struct ostream *output;
    struct director *dir;

    struct timeout *to_ring_sync_abort;
    struct director_reset_cmd *reset_cmd;
    struct director_kick_cmd *kick_cmd;
    doveadm_connection_ring_sync_callback_t *ring_sync_callback;

    const char **cmd_pending_args;
    unsigned int cmd_pending_idx;

    bool handshaked:1;
};

static struct doveadm_connection *doveadm_connections;
static struct doveadm_connection *doveadm_ring_sync_pending_connections;
static struct director_reset_cmd *reset_cmds = NULL;
static struct director_kick_cmd *kick_cmds = NULL;

static void doveadm_connection_set_io(struct doveadm_connection *conn);
static void doveadm_connection_deinit(struct doveadm_connection **_conn);
static void
doveadm_connection_ring_sync_list_move(struct doveadm_connection *conn);
static void doveadm_connection_cmd_run_synced(struct doveadm_connection *conn);

static enum doveadm_director_cmd_ret
doveadm_cmd_host_list(struct doveadm_connection *conn,
              const char *const *args ATTR_UNUSED)
{
    struct mail_host *const *hostp;
    string_t *str = t_str_new(1024);

    array_foreach(mail_hosts_get(conn->dir->mail_hosts), hostp) {
        str_printfa(str, "%s\t%u\t%u\t",
                (*hostp)->ip_str, (*hostp)->vhost_count,
                (*hostp)->user_count);
        str_append_tabescaped(str, mail_host_get_tag(*hostp));
        str_printfa(str, "\t%c\t%ld", (*hostp)->down ? 'D' : 'U',
                (long)(*hostp)->last_updown_change);
        str_append_c(str, '\n');
    }
    str_append_c(str, '\n');
    o_stream_nsend(conn->output, str_data(str), str_len(str));
    return DOVEADM_DIRECTOR_CMD_RET_OK;
}

static enum doveadm_director_cmd_ret
doveadm_cmd_host_list_removed(struct doveadm_connection *conn,
                  const char *const *args ATTR_UNUSED)
{
    struct mail_host_list *orig_hosts_list;
    struct mail_host *const *orig_hosts, *const *cur_hosts;
    unsigned int i, j, orig_hosts_count, cur_hosts_count;
    string_t *str = t_str_new(1024);
    int ret;

    orig_hosts_list = mail_hosts_init(conn->dir->set->director_user_expire,
                      NULL);
    (void)mail_hosts_parse_and_add(orig_hosts_list,
                       conn->dir->set->director_mail_servers);

    orig_hosts = array_get(mail_hosts_get(orig_hosts_list),
                   &orig_hosts_count);
    cur_hosts = array_get(mail_hosts_get(conn->dir->mail_hosts),
                  &cur_hosts_count);

    /* the hosts are sorted by IP */
    for (i = j = 0; i < orig_hosts_count && j < cur_hosts_count; ) {
        ret = net_ip_cmp(&orig_hosts[i]->ip, &cur_hosts[j]->ip);
        if (ret == 0)
            i++, j++;
        else if (ret > 0)
            j++;
        else {
            str_printfa(str, "%s\n", orig_hosts[i]->ip_str);
            i++;
        }
    }
    for (; i < orig_hosts_count; i++)
        str_printfa(str, "%s\n", orig_hosts[i]->ip_str);
    str_append_c(str, '\n');
    o_stream_nsend(conn->output, str_data(str), str_len(str));

    mail_hosts_deinit(&orig_hosts_list);
    return DOVEADM_DIRECTOR_CMD_RET_OK;
}

static void
doveadm_director_host_append_status(const struct director_host *host,
                    const char *type, string_t *str)
{
    time_t last_failed = I_MAX(host->last_network_failure,
                   host->last_protocol_failure);
    str_printfa(str, "%s\t%u\t%s\t%"PRIdTIME_T"\t",
            host->ip_str, host->port, type,
            last_failed);
}

static void doveadm_director_append_status(struct director *dir, string_t *str)
{
    if (!dir->ring_handshaked)
        str_append(str, "ring handshaking");
    else if (dir->ring_synced)
        str_append(str, "ring synced");
    else {
        str_printfa(str, "ring syncing - last sync %d secs ago",
                (int)(ioloop_time - dir->ring_last_sync_time));
    }
    str_printfa(str, "\t%u", dir->last_sync_msecs);
}

static void
doveadm_director_connection_append_status(struct director_connection *conn,
                      string_t *str)
{
    struct director_connection_status status;

    director_connection_get_status(conn, &status);
    if (!director_connection_is_handshaked(conn)) {
        str_append(str, "handshaking - ");
        if (director_connection_is_incoming(conn))
            str_printfa(str, "%u USERs received", status.handshake_users_received);
        else
            str_printfa(str, "%u USERs sent", status.handshake_users_sent);
    } else if (director_connection_is_synced(conn))
        str_append(str, "synced");
    else
        str_append(str, "syncing");

    str_printfa(str, "\t%u\t%"PRIuUOFF_T"\t%"PRIuUOFF_T"\t%zu\t%zu\t"
            "%"PRIdTIME_T"\t%"PRIdTIME_T, status.last_ping_msecs,
            status.bytes_read, status.bytes_sent,
            status.bytes_buffered, status.peak_bytes_buffered,
            status.last_input.tv_sec, status.last_output.tv_sec);
}

static void
doveadm_director_connection_append(struct director *dir,
                   struct director_connection *conn,
                   const struct director_host *host,
                   string_t *str)
{
    const char *type;

    if (conn == dir->left)
        type = "left";
    else if (conn == dir->right)
        type = "right";
    else if (director_connection_is_incoming(conn))
        type = "in";
    else
        type = "out";

    if (host != NULL)
        doveadm_director_host_append_status(host, type, str);
    doveadm_director_connection_append_status(conn, str);
    str_append_c(str, '\n');
}

static void
doveadm_director_host_append(struct director *dir,
                 const struct director_host *host, string_t *str)
{
    const char *type;

    if (host->removed)
        type = "removed";
    else if (dir->self_host == host)
        type = "self";
    else
        type = "";

    doveadm_director_host_append_status(host, type, str);
    if (dir->self_host == host)
        doveadm_director_append_status(dir, str);
    str_append_c(str, '\n');
}

static enum doveadm_director_cmd_ret
doveadm_cmd_director_list(struct doveadm_connection *conn,
              const char *const *args ATTR_UNUSED)
{
    struct director *dir = conn->dir;
    struct director_host *const *hostp;
    string_t *str = t_str_new(1024);
    struct director_connection *const *connp;
    ARRAY(struct director_host *) hosts;

    t_array_init(&hosts, array_count(&dir->dir_hosts));
    array_append_array(&hosts, &dir->dir_hosts);
    array_sort(&hosts, director_host_cmp_p);

    /* first show incoming connections that have no known host yet */
    array_foreach(&dir->connections, connp) {
        if (director_connection_get_host(*connp) == NULL)
            doveadm_director_connection_append(dir, *connp, NULL, str);
    }

    /* show other connections and host without connections sorted by host */
    array_foreach(&hosts, hostp) {
        const struct director_host *host = *hostp;
        bool have_connections = FALSE;

        array_foreach(&dir->connections, connp) {
            const struct director_host *conn_host =
                director_connection_get_host(*connp);
            if (conn_host != host)
                continue;
            have_connections = TRUE;
            doveadm_director_connection_append(dir, *connp, host, str);
        }
        if (!have_connections)
            doveadm_director_host_append(dir, host, str);
    }

    str_append_c(str, '\n');
    o_stream_nsend(conn->output, str_data(str), str_len(str));
    return DOVEADM_DIRECTOR_CMD_RET_OK;
}

static enum doveadm_director_cmd_ret
doveadm_cmd_director_add(struct doveadm_connection *conn,
             const char *const *args)
{
    struct director_host *host;
    struct ip_addr ip;
    in_port_t port = conn->dir->self_port;

    if (args[0] == NULL ||
        net_addr2ip(args[0], &ip) < 0 ||
        (args[1] != NULL && net_str2port(args[1], &port) < 0)) {
        i_error("doveadm sent invalid DIRECTOR-ADD parameters");
        return DOVEADM_DIRECTOR_CMD_RET_FAIL;
    }

    if (director_host_lookup(conn->dir, &ip, port) == NULL) {
        host = director_host_add(conn->dir, &ip, port);
        director_notify_ring_added(host, conn->dir->self_host, TRUE);
    }
    o_stream_nsend(conn->output, "OK\n", 3);
    return DOVEADM_DIRECTOR_CMD_RET_OK;
}

static enum doveadm_director_cmd_ret
doveadm_cmd_director_remove(struct doveadm_connection *conn,
                const char *const *args)
{
    struct director_host *host;
    struct ip_addr ip;
    in_port_t port = 0;

    if (args[0] == NULL ||
        net_addr2ip(args[0], &ip) < 0 ||
        (args[1] != NULL && net_str2port(args[1], &port) < 0)) {
        i_error("doveadm sent invalid DIRECTOR-REMOVE parameters");
        return DOVEADM_DIRECTOR_CMD_RET_FAIL;
    }

    host = port != 0 ?
        director_host_lookup(conn->dir, &ip, port) :
        director_host_lookup_ip(conn->dir, &ip);
    if (host == NULL) {
        o_stream_nsend_str(conn->output, "NOTFOUND\n");
        return DOVEADM_DIRECTOR_CMD_RET_OK;
    } else {
        director_ring_remove(host, conn->dir->self_host);
        return DOVEADM_DIRECTOR_CMD_RET_RING_SYNC_OK;
    }
}

static enum doveadm_director_cmd_ret
doveadm_cmd_host_set_or_update(struct doveadm_connection *conn,
                   const char *const *args, bool update)
{
    struct director *dir = conn->dir;
    const char *ip_str, *tag = "";
    struct mail_host *host;
    struct ip_addr ip;
    unsigned int vhost_count = UINT_MAX;

    ip_str = args[0];
    if (ip_str != NULL) {
        tag = strchr(ip_str, '@');
        if (tag == NULL)
            tag = "";
        else
            ip_str = t_strdup_until(ip_str, tag++);
    }
    if (ip_str == NULL || net_addr2ip(ip_str, &ip) < 0 ||
        (args[1] != NULL && str_to_uint(args[1], &vhost_count) < 0) ||
        (args[1] == NULL && update)) {
        i_error("doveadm sent invalid %s parameters",
            update ? "HOST-UPDATE" : "HOST-SET");
        return DOVEADM_DIRECTOR_CMD_RET_FAIL;
    }
    if (vhost_count > MAX_VALID_VHOST_COUNT && vhost_count != UINT_MAX) {
        o_stream_nsend_str(conn->output, "vhost count too large\n");
        return DOVEADM_DIRECTOR_CMD_RET_OK;
    }
    host = mail_host_lookup(dir->mail_hosts, &ip);
    if (host == NULL) {
        if (update) {
            o_stream_nsend_str(conn->output, "NOTFOUND\n");
            return DOVEADM_DIRECTOR_CMD_RET_OK;
        }
        host = mail_host_add_ip(dir->mail_hosts, &ip, tag);
    } else if (tag[0] != '\0' && strcmp(mail_host_get_tag(host), tag) != 0) {
        o_stream_nsend_str(conn->output, "host tag can't be changed\n");
        return DOVEADM_DIRECTOR_CMD_RET_OK;
    } else if (host->desynced) {
        o_stream_nsend_str(conn->output,
            "host is already being updated - try again later\n");
        return DOVEADM_DIRECTOR_CMD_RET_OK;
    }
    if (vhost_count != UINT_MAX)
        mail_host_set_vhost_count(host, vhost_count, "doveadm: ");
    /* NOTE: we don't support changing a tag for an existing host.
       it needs to be removed first. otherwise it would be a bit ugly to
       handle. */
    director_update_host(dir, dir->self_host, NULL, host);

    return DOVEADM_DIRECTOR_CMD_RET_RING_SYNC_OK;
}

static enum doveadm_director_cmd_ret
doveadm_cmd_host_set(struct doveadm_connection *conn, const char *const *args)
{
    return doveadm_cmd_host_set_or_update(conn, args, FALSE);
}

static enum doveadm_director_cmd_ret
doveadm_cmd_host_update(struct doveadm_connection *conn, const char *const *args)
{
    return doveadm_cmd_host_set_or_update(conn, args, TRUE);
}

static enum doveadm_director_cmd_ret
doveadm_cmd_host_updown(struct doveadm_connection *conn, bool down,
            const char *const *args)
{
    struct mail_host *host;
    struct ip_addr ip;

    if (args[0] == NULL || net_addr2ip(args[0], &ip) < 0) {
        i_error("doveadm sent invalid %s parameters: %s",
            down ? "HOST-DOWN" : "HOST-UP",
            args[0] == NULL ? "" : args[0]);
        return DOVEADM_DIRECTOR_CMD_RET_FAIL;
    }
    host = mail_host_lookup(conn->dir->mail_hosts, &ip);
    if (host == NULL) {
        o_stream_nsend_str(conn->output, "NOTFOUND\n");
        return DOVEADM_DIRECTOR_CMD_RET_OK;
    }
    if (host->down == down) {
        o_stream_nsend_str(conn->output, "OK\n");
        return DOVEADM_DIRECTOR_CMD_RET_OK;
    } else if (host->desynced) {
        o_stream_nsend_str(conn->output,
            "host is already being updated - try again later\n");
        return DOVEADM_DIRECTOR_CMD_RET_OK;
    } else {
        mail_host_set_down(host, down, ioloop_time, "doveadm: ");
        director_update_host(conn->dir, conn->dir->self_host,
                     NULL, host);
        return DOVEADM_DIRECTOR_CMD_RET_RING_SYNC_OK;
    }
}

static enum doveadm_director_cmd_ret
doveadm_cmd_host_up(struct doveadm_connection *conn,
            const char *const *args)
{
    return doveadm_cmd_host_updown(conn, FALSE, args);
}

static enum doveadm_director_cmd_ret
doveadm_cmd_host_down(struct doveadm_connection *conn,
              const char *const *args)
{
    return doveadm_cmd_host_updown(conn, TRUE, args);
}

static enum doveadm_director_cmd_ret
doveadm_cmd_host_remove(struct doveadm_connection *conn,
            const char *const *args)
{
    struct mail_host *host;
    struct ip_addr ip;

    if (args[0] == NULL || net_addr2ip(args[0], &ip) < 0) {
        i_error("doveadm sent invalid HOST-REMOVE parameters");
        return DOVEADM_DIRECTOR_CMD_RET_FAIL;
    }
    host = mail_host_lookup(conn->dir->mail_hosts, &ip);
    if (host == NULL) {
        o_stream_nsend_str(conn->output, "NOTFOUND\n");
        return DOVEADM_DIRECTOR_CMD_RET_OK;
    } else {
        director_remove_host(conn->dir, conn->dir->self_host,
                     NULL, host);
        return DOVEADM_DIRECTOR_CMD_RET_RING_SYNC_OK;
    }
}

static void
doveadm_cmd_host_flush_all(struct doveadm_connection *conn)
{
    struct mail_host *const *hostp;
    unsigned int total_user_count = 0;

    array_foreach(mail_hosts_get(conn->dir->mail_hosts), hostp) {
        total_user_count += (*hostp)->user_count;
        director_flush_host(conn->dir, conn->dir->self_host,
                    NULL, *hostp);
    }
    i_warning("Flushed all backend hosts with %u users. This is an unsafe "
          "operation and may cause the same users to end up in multiple backends.",
          total_user_count);
    o_stream_nsend(conn->output, "OK\n", 3);
}

static enum doveadm_director_cmd_ret
doveadm_cmd_host_flush(struct doveadm_connection *conn, const char *const *args)
{
    struct mail_host *host;
    struct ip_addr ip;

    if (args[0] == NULL || args[0][0] == '\0') {
        doveadm_cmd_host_flush_all(conn);
        return DOVEADM_DIRECTOR_CMD_RET_OK;
    }

    if (net_addr2ip(args[0], &ip) < 0) {
        i_error("doveadm sent invalid HOST-FLUSH parameters");
        return DOVEADM_DIRECTOR_CMD_RET_FAIL;
    }
    host = mail_host_lookup(conn->dir->mail_hosts, &ip);
    if (host == NULL) {
        o_stream_nsend_str(conn->output, "NOTFOUND\n");
        return DOVEADM_DIRECTOR_CMD_RET_OK;
    } else {
        director_flush_host(conn->dir, conn->dir->self_host,
                    NULL, host);
        return DOVEADM_DIRECTOR_CMD_RET_RING_SYNC_OK;
    }
}

static void doveadm_reset_cmd_free(struct director_reset_cmd *cmd)
{
    DLLIST_REMOVE(&reset_cmds, cmd);

    if (cmd->iter != NULL)
        director_iterate_users_deinit(&cmd->iter);
    if (cmd->_conn != NULL)
        cmd->_conn->reset_cmd = NULL;
    i_free(cmd);
}

static bool
director_host_reset_users(struct director_reset_cmd *cmd,
              struct mail_host *host)
{
    struct director *dir = cmd->dir;
    struct user *user;
    struct mail_host *new_host;

    if (dir->users_moving_count >= cmd->max_moving_users)
        return FALSE;

    if (dir->right != NULL)
        director_connection_cork(dir->right);

    if (cmd->iter == NULL) {
        cmd->iter = director_iterate_users_init(dir, FALSE);
        cmd->users_killed = FALSE;
    }

    while ((user = director_iterate_users_next(cmd->iter)) != NULL) {
        if (user->host != host)
            continue;

        new_host = mail_host_get_by_hash(dir->mail_hosts,
                         user->username_hash,
                         mail_host_get_tag(host));
        if (new_host != host) T_BEGIN {
            if (new_host != NULL) {
                director_move_user(dir, dir->self_host, NULL,
                    user->username_hash, new_host);
            } else {
                /* there are no more available backends.
                   kick the user instead. */
                director_kill_user(dir, dir->self_host, user,
                           user->host->tag, user->host,
                           TRUE);
                cmd->users_killed = TRUE;
            }
            cmd->reset_count++;
        } T_END;
        if (dir->users_moving_count >= cmd->max_moving_users)
            break;
    }
    if (user == NULL) {
        int msecs = timeval_diff_msecs(&ioloop_timeval, &cmd->start_time);
        i_info("Moved %u users in %u hosts in %u.%03u secs (max parallel=%u)",
               cmd->reset_count, cmd->hosts_count - cmd->host_start_idx,
               msecs / 1000, msecs % 1000, cmd->max_moving_users);
        director_iterate_users_deinit(&cmd->iter);
        if (cmd->users_killed) {
            /* no more backends. we already sent kills. now remove
               the users entirely from the host. */
            director_flush_host(dir, dir->self_host, NULL, host);
        }
    }
    if (dir->right != NULL)
        director_connection_uncork(dir->right);
    return user == NULL;
}

static bool
director_reset_cmd_run(struct director_reset_cmd *cmd)
{
    struct mail_host *const *hosts;
    unsigned int count;

    hosts = array_get(mail_hosts_get(cmd->dir->mail_hosts), &count);
    if (count > cmd->hosts_count)
        count = cmd->hosts_count;
    while (cmd->host_idx < count) {
        if (!director_host_reset_users(cmd, hosts[cmd->host_idx]))
            return FALSE;
        cmd->host_idx++;
    }
    if (cmd->_conn != NULL) {
        struct doveadm_connection *conn = cmd->_conn;

        o_stream_nsend(conn->output, "OK\n", 3);
        if (conn->io == NULL)
            doveadm_connection_set_io(conn);
    }
    doveadm_reset_cmd_free(cmd);
    return TRUE;
}

static enum doveadm_director_cmd_ret
doveadm_cmd_host_reset_users(struct doveadm_connection *conn,
                 const char *const *args)
{
    struct director_reset_cmd *cmd;
    struct ip_addr ip;
    struct mail_host *const *hosts;
    unsigned int i = 0, count;
    unsigned int max_moving_users =
        conn->dir->set->director_max_parallel_moves;

    if (args[0] != NULL && args[1] != NULL &&
        (str_to_uint(args[1], &max_moving_users) < 0 ||
         max_moving_users == 0)) {
        i_error("doveadm sent invalid HOST-RESET-USERS parameters");
        return DOVEADM_DIRECTOR_CMD_RET_FAIL;
    }

    hosts = array_get(mail_hosts_get(conn->dir->mail_hosts), &count);
    if (args[0] != NULL && args[0][0] != '\0') {
        if (net_addr2ip(args[0], &ip) < 0) {
            i_error("doveadm sent invalid HOST-RESET-USERS ip: %s",
                args[0]);
            return DOVEADM_DIRECTOR_CMD_RET_FAIL;
        }

        for (i = 0; i < count; i++) {
            if (net_ip_compare(&hosts[i]->ip, &ip))
                break;
        }
        if (i == count) {
            o_stream_nsend_str(conn->output, "NOTFOUND\n");
            return DOVEADM_DIRECTOR_CMD_RET_OK;
        }
        count = i+1;
    }

    conn->reset_cmd = cmd = i_new(struct director_reset_cmd, 1);
    cmd->dir = conn->dir;
    cmd->_conn = conn;
    cmd->max_moving_users = max_moving_users;
    cmd->host_start_idx = i;
    cmd->host_idx = i;
    cmd->hosts_count = count;
    cmd->start_time = ioloop_timeval;
    DLLIST_PREPEND(&reset_cmds, cmd);

    if (!director_reset_cmd_run(cmd)) {
        /* we still have work to do. don't handle any more doveadm
           input until we're finished. */
        io_remove(&conn->io);
        return DOVEADM_DIRECTOR_CMD_RET_UNFINISHED;
    }
    return DOVEADM_DIRECTOR_CMD_RET_OK;
}

static enum doveadm_director_cmd_ret
doveadm_cmd_user_lookup(struct doveadm_connection *conn,
            const char *const *args)
{
    struct user *user;
    struct mail_host *host;
    const char *username, *tag;
    unsigned int username_hash;
    struct mail_tag *mail_tag;
    string_t *str = t_str_new(256);

    if (args[0] == NULL) {
        username = "";
        tag = "";
    } else {
        username = args[0];
        tag = args[1] != NULL ? args[1] : "";
    }
    if (str_to_uint(username, &username_hash) < 0) {
        if (!director_get_username_hash(conn->dir,
                        username, &username_hash)) {
            o_stream_nsend_str(conn->output, "TRYAGAIN\n");
            return DOVEADM_DIRECTOR_CMD_RET_OK;
        }
    }

    /* get user's current host */
    mail_tag = mail_tag_find(conn->dir->mail_hosts, tag);
    user = mail_tag == NULL ? NULL :
        user_directory_lookup(mail_tag->users, username_hash);
    if (user == NULL)
        str_append(str, "\t0");
    else {
        str_printfa(str, "%s\t%u", user->host->ip_str,
                user->timestamp +
                conn->dir->set->director_user_expire);
    }

    /* get host if it wasn't in user directory */
    host = mail_host_get_by_hash(conn->dir->mail_hosts, username_hash, tag);
    if (host == NULL)
        str_append(str, "\t");
    else
        str_printfa(str, "\t%s", host->ip_str);

    /* get host with default configuration */
    host = mail_host_get_by_hash(conn->dir->orig_config_hosts,
                     username_hash, tag);
    if (host == NULL)
        str_append(str, "\t\n");
    else
        str_printfa(str, "\t%s\n", host->ip_str);
    o_stream_nsend(conn->output, str_data(str), str_len(str));
    return DOVEADM_DIRECTOR_CMD_RET_OK;
}

static enum doveadm_director_cmd_ret
doveadm_cmd_user_list(struct doveadm_connection *conn, const char *const *args)
{
    struct director_user_iter *iter;
    struct user *user;
    struct ip_addr ip;

    if (args[0] != NULL && args[0][0] != '\0') {
        if (net_addr2ip(args[0], &ip) < 0) {
            i_error("doveadm sent invalid USER-LIST parameters");
            return DOVEADM_DIRECTOR_CMD_RET_FAIL;
        }
    } else {
        ip.family = 0;
    }

    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 {
            unsigned int expire_time = user->timestamp +
                conn->dir->set->director_user_expire;

            o_stream_nsend_str(conn->output, t_strdup_printf(
                "%u\t%u\t%s\n",
                user->username_hash, expire_time,
                user->host->ip_str));
        } T_END;
    }
    director_iterate_users_deinit(&iter);
    o_stream_nsend(conn->output, "\n", 1);
    return DOVEADM_DIRECTOR_CMD_RET_OK;
}

static enum doveadm_director_cmd_ret
doveadm_cmd_user_move(struct doveadm_connection *conn, const char *const *args)
{
    unsigned int username_hash;
    struct user *user;
    struct mail_host *host;
    struct ip_addr ip;

    if (args[0] == NULL || args[1] == NULL ||
        net_addr2ip(args[1], &ip) < 0) {
        i_error("doveadm sent invalid USER-MOVE parameters");
        return DOVEADM_DIRECTOR_CMD_RET_FAIL;
    }
    host = mail_host_lookup(conn->dir->mail_hosts, &ip);
    if (host == NULL) {
        o_stream_nsend_str(conn->output, "NOTFOUND\n");
        return DOVEADM_DIRECTOR_CMD_RET_OK;
    }

    if (str_to_uint(args[0], &username_hash) < 0) {
        if (!director_get_username_hash(conn->dir,
                        args[0], &username_hash)) {
            o_stream_nsend_str(conn->output, "TRYAGAIN\n");
            return DOVEADM_DIRECTOR_CMD_RET_OK;
        }
    }

    user = user_directory_lookup(host->tag->users, username_hash);
    if (user != NULL && USER_IS_BEING_KILLED(user)) {
        o_stream_nsend_str(conn->output, "TRYAGAIN\n");
        return DOVEADM_DIRECTOR_CMD_RET_OK;
    }

    if (user == NULL || user->host != host) {
        director_move_user(conn->dir, conn->dir->self_host, NULL,
                   username_hash, host);
    } else {
        /* already the correct host. reset the user's timeout. */
        user_directory_refresh(host->tag->users, user);
        director_update_user(conn->dir, conn->dir->self_host, user);
    }
    o_stream_nsend(conn->output, "OK\n", 3);
    return DOVEADM_DIRECTOR_CMD_RET_OK;
}

static void doveadm_kick_cmd_free(struct director_kick_cmd **_cmd)
{
    struct director_kick_cmd *cmd = *_cmd;
    *_cmd = NULL;

    if (cmd->_conn != NULL)
        cmd->_conn->kick_cmd = NULL;

    i_free(cmd->field);
    i_free(cmd->value);
    i_free(cmd->mask);
    i_free(cmd);
}

static bool doveadm_cmd_user_kick_run(struct director_kick_cmd *cmd)
{
    if (cmd->dir->users_kicking_count >=
        cmd->dir->set->director_max_parallel_kicks)
        return FALSE;

    if (cmd->alt)
        director_kick_user_alt(cmd->dir, cmd->dir->self_host,
                       NULL, cmd->field, cmd->value);
    else
        director_kick_user(cmd->dir, cmd->dir->self_host,
                       NULL, cmd->mask);
    if (cmd->_conn != NULL) {
        struct doveadm_connection *conn = cmd->_conn;

        o_stream_nsend(conn->output, "OK\n", 3);
        if (conn->io == NULL)
            doveadm_connection_set_io(conn);
    }
    DLLIST_REMOVE(&kick_cmds, cmd);
    doveadm_kick_cmd_free(&cmd);
    return TRUE;
}

static enum doveadm_director_cmd_ret
doveadm_cmd_user_kick(struct doveadm_connection *conn, const char *const *args)
{
    struct director_kick_cmd *cmd;
    bool wait = TRUE;

    if (args[0] == NULL) {
        i_error("doveadm sent invalid USER-KICK parameters");
        return DOVEADM_DIRECTOR_CMD_RET_FAIL;
    }

    if (null_strcmp(args[1], "nowait") == 0)
        wait = FALSE;

    cmd = conn->kick_cmd = i_new(struct director_kick_cmd, 1);
    cmd->alt = FALSE;
    cmd->mask = i_strdup(args[0]);
    cmd->dir = conn->dir;
    cmd->_conn = conn;

    DLLIST_PREPEND(&kick_cmds, cmd);

    if (!doveadm_cmd_user_kick_run(cmd)) {
        if (wait) {
            /* we have work to do, wait until it finishes */
            io_remove(&conn->io);
            return DOVEADM_DIRECTOR_CMD_RET_UNFINISHED;
        } else {
            o_stream_nsend_str(conn->output, "TRYAGAIN\n");
            /* need to remove it here */
            DLLIST_REMOVE(&kick_cmds, cmd);
            doveadm_kick_cmd_free(&cmd);
        }
    }

    return DOVEADM_DIRECTOR_CMD_RET_OK;
}

static enum doveadm_director_cmd_ret
doveadm_cmd_user_kick_alt(struct doveadm_connection *conn, const char *const *args)
{
    bool wait = TRUE;
    struct director_kick_cmd *cmd;

    if (str_array_length(args) < 2) {
        i_error("doveadm sent invalid USER-KICK-ALT parameters");
        return DOVEADM_DIRECTOR_CMD_RET_FAIL;
    }

    if (null_strcmp(args[2], "nowait") == 0)
        wait = FALSE;

    conn->kick_cmd = cmd = i_new(struct director_kick_cmd, 1);
    cmd->alt = TRUE;
    cmd->field = i_strdup(args[0]);
    cmd->value = i_strdup(args[1]);
    cmd->dir = conn->dir;
    cmd->_conn = conn;

    DLLIST_PREPEND(&kick_cmds, cmd);

    if (!doveadm_cmd_user_kick_run(cmd)) {
        if (wait) {
            /* we have work to do, wait until it finishes */
            io_remove(&conn->io);
            return DOVEADM_DIRECTOR_CMD_RET_UNFINISHED;
        } else {
            o_stream_nsend_str(conn->output, "TRYAGAIN\n");
            DLLIST_REMOVE(&kick_cmds, cmd);
            doveadm_kick_cmd_free(&cmd);
        }
    }

    return DOVEADM_DIRECTOR_CMD_RET_OK;
}

struct {
    const char *name;
    enum doveadm_director_cmd_ret (*cmd)
        (struct doveadm_connection *conn, const char *const *args);
    enum doveadm_director_cmd_flag flags;
} doveadm_director_commands[] = {
    { "HOST-LIST", doveadm_cmd_host_list, 0 },
    { "HOST-LIST-REMOVED", doveadm_cmd_host_list_removed, 0 },
    { "DIRECTOR-LIST", doveadm_cmd_director_list, 0 },
    { "DIRECTOR-ADD", doveadm_cmd_director_add, DOVEADM_DIRECTOR_CMD_FLAG_PRE_RING_SYNC },
    { "DIRECTOR-REMOVE", doveadm_cmd_director_remove, DOVEADM_DIRECTOR_CMD_FLAG_PRE_RING_SYNC },
    { "HOST-SET", doveadm_cmd_host_set, DOVEADM_DIRECTOR_CMD_FLAG_PRE_RING_SYNC },
    { "HOST-UPDATE", doveadm_cmd_host_update, DOVEADM_DIRECTOR_CMD_FLAG_PRE_RING_SYNC },
    { "HOST-UP", doveadm_cmd_host_up, DOVEADM_DIRECTOR_CMD_FLAG_PRE_RING_SYNC },
    { "HOST-DOWN", doveadm_cmd_host_down, DOVEADM_DIRECTOR_CMD_FLAG_PRE_RING_SYNC },
    { "HOST-REMOVE", doveadm_cmd_host_remove, DOVEADM_DIRECTOR_CMD_FLAG_PRE_RING_SYNC },
    { "HOST-FLUSH", doveadm_cmd_host_flush, DOVEADM_DIRECTOR_CMD_FLAG_PRE_RING_SYNC },
    { "HOST-RESET-USERS", doveadm_cmd_host_reset_users, 0 },
    { "USER-LOOKUP", doveadm_cmd_user_lookup, 0 },
    { "USER-LIST", doveadm_cmd_user_list, 0 },
    { "USER-MOVE", doveadm_cmd_user_move, 0 },
    { "USER-KICK", doveadm_cmd_user_kick, 0 },
    { "USER-KICK-ALT", doveadm_cmd_user_kick_alt, 0 },
};

static void
doveadm_connection_ring_sync_timeout(struct doveadm_connection *conn)
{
    doveadm_connection_ring_sync_list_move(conn);
    o_stream_nsend_str(conn->output, "Ring sync timed out\n");

    doveadm_connection_set_io(conn);
    io_set_pending(conn->io);

    i_free_and_null(conn->cmd_pending_args);
}

static void
doveadm_connection_set_ring_sync_callback(struct doveadm_connection *conn,
                      doveadm_connection_ring_sync_callback_t *callback)
{
    i_assert(conn->ring_sync_callback == NULL);
    i_assert(conn->to_ring_sync_abort == NULL);

    conn->ring_sync_callback = callback;
    io_remove(&conn->io);
    DLLIST_REMOVE(&doveadm_connections, conn);
    DLLIST_PREPEND(&doveadm_ring_sync_pending_connections, conn);
    conn->to_ring_sync_abort =
        timeout_add(DOVEADM_CONNECTION_RING_SYNC_TIMEOUT_MSECS,
                doveadm_connection_ring_sync_timeout, conn);
}

static void doveadm_connection_ret_ok(struct doveadm_connection *conn)
{
    o_stream_nsend(conn->output, "OK\n", 3);
}

static enum doveadm_director_cmd_ret
doveadm_connection_cmd_run(struct doveadm_connection *conn,
               const char *const *args, unsigned int i)
{
    enum doveadm_director_cmd_ret ret;

    if ((doveadm_director_commands[i].flags &
         DOVEADM_DIRECTOR_CMD_FLAG_PRE_RING_SYNC) != 0 &&
        !conn->dir->ring_synced) {
        /* wait for ring to be synced before running the command */
        conn->cmd_pending_args = p_strarray_dup(default_pool, args);
        conn->cmd_pending_idx = i;
        doveadm_connection_set_ring_sync_callback(conn,
            doveadm_connection_cmd_run_synced);
        return DOVEADM_DIRECTOR_CMD_RET_UNFINISHED;
    }

    ret = doveadm_director_commands[i].cmd(conn, args);
    if (ret != DOVEADM_DIRECTOR_CMD_RET_RING_SYNC_OK)
        return ret;
    /* Delay sending OK until ring is synced. This way doveadm will know
       whether the call actually succeeded or not. */
    if (conn->dir->ring_synced) {
        /* director is alone */
        i_assert(conn->dir->right == NULL && conn->dir->left == NULL);
        o_stream_nsend(conn->output, "OK\n", 3);
        return DOVEADM_DIRECTOR_CMD_RET_OK;
    }
    doveadm_connection_set_ring_sync_callback(conn, doveadm_connection_ret_ok);
    return DOVEADM_DIRECTOR_CMD_RET_RING_SYNC_OK;
}

static void doveadm_connection_cmd_run_synced(struct doveadm_connection *conn)
{
    const char **args = conn->cmd_pending_args;

    conn->cmd_pending_args = NULL;
    (void)doveadm_connection_cmd_run(conn, args, conn->cmd_pending_idx);
    i_free(args);
}

static enum doveadm_director_cmd_ret
doveadm_connection_cmd(struct doveadm_connection *conn, const char *line)
{
    const char *cmd, *const *args;

    args = t_strsplit_tabescaped(line);
    if (args[0] == NULL) {
        i_error("doveadm sent empty command line");
        return DOVEADM_DIRECTOR_CMD_RET_FAIL;
    }
    cmd = args[0];
    args++;

    for (unsigned int i = 0; i < N_ELEMENTS(doveadm_director_commands); i++) {
        if (strcmp(doveadm_director_commands[i].name, cmd) == 0)
            return doveadm_connection_cmd_run(conn, args, i);
    }
    i_error("doveadm sent unknown command: %s", line);
    return DOVEADM_DIRECTOR_CMD_RET_FAIL;
}

static void doveadm_connection_input(struct doveadm_connection *conn)
{
    const char *line;
    enum doveadm_director_cmd_ret ret = DOVEADM_DIRECTOR_CMD_RET_OK;

    if (!conn->handshaked) {
        if ((line = i_stream_read_next_line(conn->input)) == NULL) {
            if (conn->input->eof || conn->input->stream_errno != 0)
                doveadm_connection_deinit(&conn);
            return;
        }

        if (!version_string_verify(line, "director-doveadm",
                       DOVEADM_PROTOCOL_VERSION_MAJOR)) {
            i_error("doveadm not compatible with this server "
                "(mixed old and new binaries?)");
            doveadm_connection_deinit(&conn);
            return;
        }
        conn->handshaked = TRUE;
    }

    while ((line = i_stream_read_next_line(conn->input)) != NULL &&
           ret == DOVEADM_DIRECTOR_CMD_RET_OK) {
        T_BEGIN {
            ret = doveadm_connection_cmd(conn, line);
        } T_END;
    }
    if (conn->input->eof || conn->input->stream_errno != 0 ||
        ret == DOVEADM_DIRECTOR_CMD_RET_FAIL)
        doveadm_connection_deinit(&conn);
}

static void doveadm_connection_set_io(struct doveadm_connection *conn)
{
    conn->io = io_add(conn->fd, IO_READ, doveadm_connection_input, conn);
}

struct doveadm_connection *
doveadm_connection_init(struct director *dir, int fd)
{
    struct doveadm_connection *conn;

    conn = i_new(struct doveadm_connection, 1);
    conn->fd = fd;
    conn->dir = dir;
    conn->input = i_stream_create_fd(conn->fd, 1024);
    conn->output = o_stream_create_fd(conn->fd, (size_t)-1);
    o_stream_set_no_error_handling(conn->output, TRUE);
    doveadm_connection_set_io(conn);
    o_stream_nsend_str(conn->output, DOVEADM_HANDSHAKE);

    DLLIST_PREPEND(&doveadm_connections, conn);
    return conn;
}

static void doveadm_connection_deinit(struct doveadm_connection **_conn)
{
    struct doveadm_connection *conn = *_conn;

    *_conn = NULL;

    i_assert(conn->to_ring_sync_abort == NULL);

    if (conn->reset_cmd != NULL) {
        /* finish the move even if doveadm disconnected */
        conn->reset_cmd->_conn = NULL;
    }
    if (conn->kick_cmd != NULL) {
        /* finish the kick even if doveadm disconnected */
        conn->kick_cmd->_conn = NULL;
    }

    DLLIST_REMOVE(&doveadm_connections, conn);
    io_remove(&conn->io);
    i_stream_unref(&conn->input);
    o_stream_unref(&conn->output);
    if (close(conn->fd) < 0)
        i_error("close(doveadm connection) failed: %m");
    i_free(conn);

    master_service_client_connection_destroyed(master_service);
}

static void
doveadm_connection_ring_sync_list_move(struct doveadm_connection *conn)
{
    timeout_remove(&conn->to_ring_sync_abort);
    DLLIST_REMOVE(&doveadm_ring_sync_pending_connections, conn);
    DLLIST_PREPEND(&doveadm_connections, conn);
}

void doveadm_connections_deinit(void)
{
    while (reset_cmds != NULL)
        doveadm_reset_cmd_free(reset_cmds);

    unsigned int pending_count = 0;
    while (doveadm_ring_sync_pending_connections != NULL) {
        doveadm_connection_ring_sync_list_move(doveadm_ring_sync_pending_connections);
        pending_count++;
    }
    if (pending_count > 0)
        i_warning("Shutting down while %u doveadm connections were waiting for ring sync", pending_count);
    while (doveadm_connections != NULL) {
        struct doveadm_connection *conn = doveadm_connections;

        doveadm_connection_deinit(&conn);
    }
}

void doveadm_connections_kick_callback(struct director *dir ATTR_UNUSED)
{
    while(kick_cmds != NULL)
        if (!doveadm_cmd_user_kick_run(kick_cmds))
            break;
}

static void doveadm_connections_continue_reset_cmds(void)
{
    while (reset_cmds != NULL) {
        if (!director_reset_cmd_run(reset_cmds))
            break;
    }
}

void doveadm_connections_ring_synced(void)
{
    while (doveadm_ring_sync_pending_connections != NULL) {
        struct doveadm_connection *conn =
            doveadm_ring_sync_pending_connections;
        doveadm_connection_ring_sync_callback_t *callback =
            conn->ring_sync_callback;

        conn->ring_sync_callback = NULL;
        doveadm_connection_ring_sync_list_move(conn);
        doveadm_connection_set_io(conn);
        io_set_pending(conn->io);
        callback(conn);
    }
    doveadm_connections_continue_reset_cmds();
}