src/lib/connection.c

	connection.c revision ed567dac7e55ab3e8dd53d9c86c31ebb2032d4df
/* Copyright (c) 2013-2018 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "ioloop.h"
#include "istream.h"
#include "istream-unix.h"
#include "ostream.h"
#include "ostream-unix.h"
#include "iostream.h"
#include "net.h"
#include "strescape.h"
#include "llist.h"
#include "time-util.h"
#include "connection.h"

#include <unistd.h>

static void connection_idle_timeout(struct connection *conn)
{
    conn->disconnect_reason = CONNECTION_DISCONNECT_IDLE_TIMEOUT;
    conn->list->v.destroy(conn);
}

static void connection_connect_timeout(struct connection *conn)
{
    conn->disconnect_reason = CONNECTION_DISCONNECT_CONNECT_TIMEOUT;
    conn->list->v.destroy(conn);
}

void connection_input_default(struct connection *conn)
{
    const char *line;
    struct istream *input;
    struct ostream *output;
    int ret = 0;

    switch (connection_input_read(conn)) {
    case -1:
        return;
    case 0: /* allow calling this function for buffered input */
    case 1:
        break;
    default:
        i_unreached();
    }

    input = conn->input;
    output = conn->output;
    i_stream_ref(input);
    if (output != NULL) {
        o_stream_ref(output);
        o_stream_cork(output);
    }
    while (!input->closed && (line = i_stream_next_line(input)) != NULL) {
        T_BEGIN {
            ret = conn->list->v.input_line(conn, line);
        } T_END;
        if (ret <= 0)
            break;
    }
    if (output != NULL) {
        o_stream_uncork(output);
        o_stream_unref(&output);
    }
    if (ret < 0 && !input->closed) {
        conn->disconnect_reason = CONNECTION_DISCONNECT_DEINIT;
        conn->list->v.destroy(conn);
    }
    i_stream_unref(&input);
}

int connection_verify_version(struct connection *conn,
                  const char *const *args)
{
    unsigned int recv_major_version;

    /* VERSION <tab> service_name <tab> major version <tab> minor version */
    if (str_array_length(args) != 4 ||
        strcmp(args[0], "VERSION") != 0 ||
        str_to_uint(args[2], &recv_major_version) < 0 ||
        str_to_uint(args[3], &conn->minor_version) < 0) {
        i_error("%s didn't reply with a valid VERSION line: %s",
            conn->name, t_strarray_join(args, "\t"));
        return -1;
    }

    if (strcmp(args[1], conn->list->set.service_name_in) != 0) {
        i_error("%s: Connected to wrong socket type. "
            "We want '%s', but received '%s'", conn->name,
            conn->list->set.service_name_in, args[1]);
        return -1;
    }

    if (recv_major_version != conn->list->set.major_version) {
        i_error("%s: Socket supports major version %u, "
            "but we support only %u (mixed old and new binaries?)",
            conn->name, recv_major_version,
            conn->list->set.major_version);
        return -1;
    }
    return 0;
}

int connection_input_line_default(struct connection *conn, const char *line)
{
    const char *const *args;

    args = t_strsplit_tabescaped(line);
    if (!conn->version_received) {
        if (connection_verify_version(conn, args) < 0)
            return -1;
        conn->version_received = TRUE;
        return 1;
    }
    if (args[0] == NULL && !conn->list->set.allow_empty_args_input) {
        i_error("%s: Unexpectedly received empty line", conn->name);
        return -1;
    }

    return conn->list->v.input_args(conn, args);
}

static void connection_init_streams(struct connection *conn)
{
    const struct connection_settings *set = &conn->list->set;

    i_assert(conn->io == NULL);
    i_assert(conn->input == NULL);
    i_assert(conn->output == NULL);
    i_assert(conn->to == NULL);

    conn->version_received = set->major_version == 0;

    if (set->input_max_size != 0) {
        if (conn->unix_socket)
            conn->input = i_stream_create_unix(conn->fd_in,
                               set->input_max_size);
        else
            conn->input = i_stream_create_fd(conn->fd_in,
                             set->input_max_size);
        i_stream_set_name(conn->input, conn->name);
        conn->io = io_add_istream(conn->input, *conn->list->v.input, conn);
    } else {
        conn->io = io_add(conn->fd_in, IO_READ, *conn->list->v.input, conn);
    }
    if (set->output_max_size != 0) {
        if (conn->unix_socket)
            conn->output = o_stream_create_unix(conn->fd_out,
                                set->output_max_size);
        else
            conn->output = o_stream_create_fd(conn->fd_out,
                              set->output_max_size);
        o_stream_set_no_error_handling(conn->output, TRUE);
        o_stream_set_finish_via_child(conn->output, FALSE);
        o_stream_set_name(conn->output, conn->name);
    }
    if (set->input_idle_timeout_secs != 0) {
        conn->to = timeout_add(set->input_idle_timeout_secs*1000,
                       connection_idle_timeout, conn);
    }
    if (set->major_version != 0 && !set->dont_send_version) {
        o_stream_nsend_str(conn->output, t_strdup_printf(
            "VERSION\t%s\t%u\t%u\n", set->service_name_out,
            set->major_version, set->minor_version));
    }
}

void connection_streams_changed(struct connection *conn)
{
    const struct connection_settings *set = &conn->list->set;

    if (set->input_max_size != 0 && conn->io != NULL) {
        io_remove(&conn->io);
        conn->io = io_add_istream(conn->input, *conn->list->v.input, conn);
    }
}

static void connection_client_connected(struct connection *conn, bool success)
{
    i_assert(conn->list->set.client);

    conn->connect_finished = ioloop_timeval;
    if (success)
        connection_init_streams(conn);
    if (conn->list->v.client_connected != NULL)
        conn->list->v.client_connected(conn, success);
    if (!success) {
        conn->disconnect_reason =
            CONNECTION_DISCONNECT_CONN_CLOSED;
        conn->list->v.destroy(conn);
    }
}

void connection_init(struct connection_list *list,
             struct connection *conn)
{
    conn->fd_in = -1;
    conn->fd_out = -1;
    conn->name = NULL;

    if (conn->list != NULL) {
        i_assert(conn->list == list);
    } else {
        conn->list = list;
        DLLIST_PREPEND(&list->connections, conn);
        list->connections_count++;
    }
}

void connection_init_server(struct connection_list *list,
                struct connection *conn, const char *name,
                int fd_in, int fd_out)
{
    i_assert(name != NULL);
    i_assert(!list->set.client);

    connection_init(list, conn);

    conn->name = i_strdup(name);
    conn->fd_in = fd_in;
    conn->fd_out = fd_out;
    connection_init_streams(conn);
}

void connection_init_client_ip(struct connection_list *list,
                   struct connection *conn,
                   const struct ip_addr *ip, in_port_t port)
{
    i_assert(list->set.client);

    connection_init(list, conn);

    conn->fd_in = conn->fd_out = -1;
    conn->name = i_strdup_printf("%s:%u", net_ip2addr(ip), port);

    conn->ip = *ip;
    conn->port = port;
}

void connection_init_client_unix(struct connection_list *list,
                 struct connection *conn, const char *path)
{
    i_assert(list->set.client);

    connection_init(list, conn);

    conn->fd_in = conn->fd_out = -1;
    conn->name = i_strdup(path);
    conn->unix_socket = TRUE;
}

void connection_init_from_streams(struct connection_list *list,
                struct connection *conn, const char *name,
                struct istream *input, struct ostream *output)
{
    i_assert(name != NULL);

    connection_init(list, conn);

    conn->name = i_strdup(name);
    conn->fd_in = i_stream_get_fd(input);
    conn->fd_out = o_stream_get_fd(output);

    i_assert(conn->fd_in >= 0);
    i_assert(conn->fd_out >= 0);
    i_assert(conn->io == NULL);
    i_assert(conn->input == NULL);
    i_assert(conn->output == NULL);
    i_assert(conn->to == NULL);

    conn->input = input;
    i_stream_ref(conn->input);
    i_stream_set_name(conn->input, conn->name);

    conn->output = output;
    o_stream_ref(conn->output);
    o_stream_set_no_error_handling(conn->output, TRUE);
    o_stream_set_name(conn->output, conn->name);

    conn->io = io_add_istream(conn->input, *list->v.input, conn);

    if (list->v.client_connected != NULL)
        list->v.client_connected(conn, TRUE);
}

static void connection_socket_connected(struct connection *conn)
{
    io_remove(&conn->io);
    timeout_remove(&conn->to);

    errno = net_geterror(conn->fd_in);
    connection_client_connected(conn, errno == 0);
}

int connection_client_connect(struct connection *conn)
{
    const struct connection_settings *set = &conn->list->set;
    int fd;

    i_assert(conn->list->set.client);
    i_assert(conn->fd_in == -1);

    if (conn->port != 0)
        fd = net_connect_ip(&conn->ip, conn->port, NULL);
    else if (conn->list->set.unix_client_connect_msecs == 0)
        fd = net_connect_unix(conn->name);
    else
        fd = net_connect_unix_with_retries(conn->name, conn->list->set.unix_client_connect_msecs);
    if (fd == -1)
        return -1;
    conn->fd_in = conn->fd_out = fd;
    conn->connect_started = ioloop_timeval;

    if (conn->port != 0 ||
        conn->list->set.delayed_unix_client_connected_callback) {
        conn->io = io_add(conn->fd_out, IO_WRITE,
                  connection_socket_connected, conn);
        if (set->client_connect_timeout_msecs != 0) {
            conn->to = timeout_add(set->client_connect_timeout_msecs,
                           connection_connect_timeout, conn);
        }
    } else {
        connection_client_connected(conn, TRUE);
    }
    return 0;
}

void connection_disconnect(struct connection *conn)
{
    conn->last_input = 0;
    i_zero(&conn->last_input_tv);
    timeout_remove(&conn->to);
    io_remove(&conn->io);
    i_stream_close(conn->input);
    i_stream_destroy(&conn->input);
    o_stream_close(conn->output);
    o_stream_destroy(&conn->output);
    fd_close_maybe_stdio(&conn->fd_in, &conn->fd_out);
}

void connection_deinit(struct connection *conn)
{
    i_assert(conn->list->connections_count > 0);

    conn->list->connections_count--;
    DLLIST_REMOVE(&conn->list->connections, conn);

    connection_disconnect(conn);
    i_free(conn->name);
}

int connection_input_read(struct connection *conn)
{
    conn->last_input = ioloop_time;
    conn->last_input_tv = ioloop_timeval;
    if (conn->to != NULL)
        timeout_reset(conn->to);

    switch (i_stream_read(conn->input)) {
    case -2:
        /* buffer full */
        switch (conn->list->set.input_full_behavior) {
        case CONNECTION_BEHAVIOR_DESTROY:
            conn->disconnect_reason =
                CONNECTION_DISCONNECT_BUFFER_FULL;
            conn->list->v.destroy(conn);
            return -1;
        case CONNECTION_BEHAVIOR_ALLOW:
            return -2;
        }
        i_unreached();
    case -1:
        /* disconnected */
        conn->disconnect_reason =
            CONNECTION_DISCONNECT_CONN_CLOSED;
        conn->list->v.destroy(conn);
        return -1;
    case 0:
        /* nothing new read */
        return 0;
    default:
        /* something was read */
        return 1;
    }
}

const char *connection_disconnect_reason(struct connection *conn)
{
    switch (conn->disconnect_reason) {
    case CONNECTION_DISCONNECT_DEINIT:
        return "Deinitializing";
    case CONNECTION_DISCONNECT_CONNECT_TIMEOUT: {
        unsigned int msecs =
            conn->list->set.client_connect_timeout_msecs;
        return t_strdup_printf("connect() timed out in %u.%03u secs",
                       msecs/1000, msecs%1000);
    }
    case CONNECTION_DISCONNECT_IDLE_TIMEOUT:
        return "Idle timeout";
    case CONNECTION_DISCONNECT_CONN_CLOSED:
        if (conn->input == NULL)
            return t_strdup_printf("connect() failed: %m");
        /* fall through */
    case CONNECTION_DISCONNECT_NOT:
    case CONNECTION_DISCONNECT_BUFFER_FULL:
        return io_stream_get_disconnect_reason(conn->input, conn->output);
    }
    i_unreached();
}

const char *connection_input_timeout_reason(struct connection *conn)
{
    if (conn->last_input_tv.tv_sec != 0) {
        int diff = timeval_diff_msecs(&ioloop_timeval, &conn->last_input_tv);
        return t_strdup_printf("No input for %u.%03u secs",
                       diff/1000, diff%1000);
    } else if (conn->connect_finished.tv_sec != 0) {
        int diff = timeval_diff_msecs(&ioloop_timeval, &conn->connect_finished);
        return t_strdup_printf(
            "No input since connected %u.%03u secs ago",
            diff/1000, diff%1000);
    } else {
        int diff = timeval_diff_msecs(&ioloop_timeval, &conn->connect_started);
        return t_strdup_printf("connect() timed out after %u.%03u secs",
                       diff/1000, diff%1000);
    }
}

void connection_switch_ioloop_to(struct connection *conn,
                 struct ioloop *ioloop)
{
    if (conn->io != NULL)
        conn->io = io_loop_move_io_to(ioloop, &conn->io);
    if (conn->to != NULL)
        conn->to = io_loop_move_timeout_to(ioloop, &conn->to);
    if (conn->input != NULL)
        i_stream_switch_ioloop_to(conn->input, ioloop);
    if (conn->output != NULL)
        o_stream_switch_ioloop_to(conn->output, ioloop);
}

void connection_switch_ioloop(struct connection *conn)
{
    connection_switch_ioloop_to(conn, current_ioloop);
}

struct connection_list *
connection_list_init(const struct connection_settings *set,
             const struct connection_vfuncs *vfuncs)
{
    struct connection_list *list;

    i_assert(vfuncs->input != NULL ||
         set->input_full_behavior != CONNECTION_BEHAVIOR_ALLOW);
    i_assert(set->major_version == 0 ||
         (set->service_name_in != NULL &&
          set->service_name_out != NULL &&
          set->output_max_size != 0));

    list = i_new(struct connection_list, 1);
    list->set = *set;
    list->v = *vfuncs;

    if (list->v.input == NULL)
        list->v.input = connection_input_default;
    if (list->v.input_line == NULL)
        list->v.input_line = connection_input_line_default;

    return list;
}

void connection_list_deinit(struct connection_list **_list)
{
    struct connection_list *list = *_list;
    struct connection *conn;

    *_list = NULL;

    while (list->connections != NULL) {
        conn = list->connections;
        conn->disconnect_reason = CONNECTION_DISCONNECT_DEINIT;
        list->v.destroy(conn);
        i_assert(conn != list->connections);
    }
    i_free(list);
}