1 files changed, 952 insertions, 0 deletions

diff --git a/src/lib/connection.c b/src/lib/connection.c
new file mode 100644
index 0000000..dae5c92
--- /dev/null
+++ b/src/lib/connection.c
@@ -0,0 +1,952 @@
+/* Copyright (c) 2013-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "str.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>
+#include <libgen.h>
+
+static void connection_handshake_ready(struct connection *conn)
+{
+	conn->handshake_received = TRUE;
+	if (conn->v.handshake_ready != NULL)
+		conn->v.handshake_ready(conn);
+}
+
+static void connection_closed(struct connection *conn,
+			      enum connection_disconnect_reason reason)
+{
+	conn->disconnect_reason = reason;
+	conn->v.destroy(conn);
+}
+
+static void connection_idle_timeout(struct connection *conn)
+{
+	connection_closed(conn, CONNECTION_DISCONNECT_IDLE_TIMEOUT);
+}
+
+static void connection_connect_timeout(struct connection *conn)
+{
+	connection_closed(conn, CONNECTION_DISCONNECT_CONNECT_TIMEOUT);
+}
+
+void connection_input_default(struct connection *conn)
+{
+	const char *line;
+	struct istream *input;
+	struct ostream *output;
+	int ret = 0;
+
+	if (!conn->handshake_received &&
+	    conn->v.handshake != NULL) {
+		if ((ret = conn->v.handshake(conn)) < 0) {
+			connection_closed(
+				conn, CONNECTION_DISCONNECT_HANDSHAKE_FAILED);
+			return;
+		} else if (ret == 0) {
+			return;
+		} else {
+			connection_handshake_ready(conn);
+		}
+	}
+
+	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 {
+			if (!conn->handshake_received &&
+			    conn->v.handshake_line != NULL) {
+				ret = conn->v.handshake_line(conn, line);
+				if (ret > 0)
+					connection_handshake_ready(conn);
+				else if (ret == 0)
+					/* continue reading */
+					ret = 1;
+				else
+					conn->disconnect_reason =
+						CONNECTION_DISCONNECT_HANDSHAKE_FAILED;
+			} else {
+				ret = conn->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) {
+		enum connection_disconnect_reason reason =
+			conn->disconnect_reason;
+		if (reason == CONNECTION_DISCONNECT_NOT)
+			reason = CONNECTION_DISCONNECT_DEINIT;
+		connection_closed(conn, reason);
+	}
+	i_stream_unref(&input);
+}
+
+int connection_verify_version(struct connection *conn,
+			      const char *service_name,
+			      unsigned int major_version,
+			      unsigned int minor_version)
+{
+	i_assert(!conn->version_received);
+
+	if (strcmp(service_name, conn->list->set.service_name_in) != 0) {
+		e_error(conn->event, "Connected to wrong socket type. "
+			"We want '%s', but received '%s'",
+			conn->list->set.service_name_in, service_name);
+		return -1;
+	}
+
+	if (major_version != conn->list->set.major_version) {
+		e_error(conn->event, "Socket supports major version %u, "
+			"but we support only %u (mixed old and new binaries?)",
+			major_version, conn->list->set.major_version);
+		return -1;
+	}
+
+	conn->minor_version = minor_version;
+	conn->version_received = TRUE;
+	return 0;
+}
+
+int connection_handshake_args_default(struct connection *conn,
+				      const char *const *args)
+{
+	unsigned int major_version, minor_version;
+
+	if (conn->version_received)
+		return 1;
+
+	/* 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], &major_version) < 0 ||
+	    str_to_uint(args[3], &minor_version) < 0) {
+		e_error(conn->event, "didn't reply with a valid VERSION line: %s",
+			t_strarray_join(args, "\t"));
+		return -1;
+	}
+
+	if (connection_verify_version(conn, args[1],
+				      major_version, minor_version) < 0)
+		return -1;
+	return 1;
+}
+
+int connection_input_line_default(struct connection *conn, const char *line)
+{
+	const char *const *args;
+
+	args = t_strsplit_tabescaped(line);
+	if (args[0] == NULL && !conn->list->set.allow_empty_args_input) {
+		e_error(conn->event, "Unexpectedly received empty line");
+		return -1;
+	}
+
+	if (!conn->handshake_received &&
+	    (conn->v.handshake_args != connection_handshake_args_default ||
+	     conn->list->set.major_version != 0)) {
+		int ret;
+		if ((ret = conn->v.handshake_args(conn, args)) == 0)
+			ret = 1; /* continue reading */
+		else if (ret > 0)
+			connection_handshake_ready(conn);
+		else {
+			conn->disconnect_reason =
+				CONNECTION_DISCONNECT_HANDSHAKE_FAILED;
+		}
+		return ret;
+	} else if (!conn->handshake_received) {
+		/* we don't do handshakes */
+		connection_handshake_ready(conn);
+	}
+
+	/* version must be handled though, by something */
+	i_assert(conn->version_received);
+
+	return conn->v.input_args(conn, args);
+}
+
+void connection_input_halt(struct connection *conn)
+{
+	io_remove(&conn->io);
+	timeout_remove(&conn->to);
+}
+
+static void
+connection_input_resume_full(struct connection *conn, bool set_io_pending)
+{
+	i_assert(!conn->disconnected);
+
+	if (conn->io != NULL) {
+		/* do nothing */
+	} else if (conn->input != NULL) {
+		conn->io = io_add_istream_to(conn->ioloop, conn->input,
+					     *conn->v.input, conn);
+		if (set_io_pending)
+			io_set_pending(conn->io);
+	} else if (conn->fd_in != -1) {
+		conn->io = io_add_to(conn->ioloop, conn->fd_in, IO_READ,
+				     *conn->v.input, conn);
+		if (set_io_pending)
+			io_set_pending(conn->io);
+	}
+	if (conn->input_idle_timeout_secs != 0 && conn->to == NULL) {
+		conn->to = timeout_add_to(conn->ioloop,
+					  conn->input_idle_timeout_secs*1000,
+					  *conn->v.idle_timeout, conn);
+	}
+}
+
+void connection_input_resume(struct connection *conn)
+{
+	connection_input_resume_full(conn, TRUE);
+}
+
+static void connection_update_property_label(struct connection *conn)
+{
+	const char *label;
+
+	if (conn->remote_ip.family == 0) {
+		if (conn->remote_uid == (uid_t)-1)
+			label = NULL;
+		else if (conn->remote_pid != (pid_t)-1) {
+			label = t_strdup_printf("pid=%ld,uid=%ld",
+						(long)conn->remote_pid,
+						(long)conn->remote_uid);
+		} else {
+			label = t_strdup_printf("uid=%ld",
+						(long)conn->remote_uid);
+		}
+	} else if (conn->remote_ip.family == AF_INET6) {
+		label = t_strdup_printf("[%s]:%u",
+					net_ip2addr(&conn->remote_ip),
+					conn->remote_port);
+	} else {
+		label = t_strdup_printf("%s:%u",
+					net_ip2addr(&conn->remote_ip),
+					conn->remote_port);
+	}
+
+	i_assert(label != NULL || conn->property_label == NULL);
+	if (conn->property_label != NULL &&
+	    strcmp(conn->property_label, label) != 0) {
+		e_debug(conn->event, "Updated peer address to %s", label);
+	}
+
+	i_free(conn->property_label);
+	conn->property_label = i_strdup(label);
+}
+
+static void connection_update_label(struct connection *conn)
+{
+	bool unix_socket = conn->unix_socket ||
+		(conn->remote_ip.family == 0 && conn->remote_uid != (uid_t)-1);
+	string_t *label;
+
+	label = t_str_new(64);
+	if (conn->base_name != NULL)
+		str_append(label, conn->base_name);
+	if (conn->property_label != NULL) {
+		if (str_len(label) == 0)
+			str_append(label, conn->property_label);
+		else {
+			str_append(label, " (");
+			str_append(label, conn->property_label);
+			str_append(label, ")");
+		}
+	}
+	if (str_len(label) == 0) {
+		if (conn->fd_in >= 0 &&
+		    (conn->fd_in == conn->fd_out || conn->fd_out < 0))
+			str_printfa(label, "fd=%d", conn->fd_in);
+		else if (conn->fd_in < 0 && conn->fd_out >= 0)
+			str_printfa(label, "fd=%d", conn->fd_out);
+		else if (conn->fd_in >= 0 && conn->fd_out >= 0) {
+			str_printfa(label, "fd_in=%d,fd_out=%d",
+				    conn->fd_in, conn->fd_out);
+		}
+	}
+	if (unix_socket && str_len(label) > 0)
+		str_insert(label, 0, "unix:");
+	if (conn->list->set.log_connection_id) {
+		if (str_len(label) > 0)
+			str_append_c(label, ' ');
+		str_printfa(label, "[%u]", conn->id);
+	}
+
+	i_free(conn->label);
+	conn->label = i_strdup(str_c(label));
+}
+
+static const char *
+connection_create_stream_name(struct connection *conn, int fd)
+{
+	string_t *name;
+
+	name = t_str_new(64);
+	str_append(name, "(conn");
+	if (conn->unix_socket ||
+	    (conn->remote_ip.family == 0 && conn->remote_uid != (uid_t)-1))
+		str_append(name, ":unix");
+	if (conn->base_name != NULL) {
+		str_append_c(name, ':');
+		str_append(name, conn->base_name);
+	} else if (conn->property_label != NULL) {
+		str_append_c(name, ':');
+		str_append(name, conn->property_label);
+	} else if (fd >= 0) {
+		str_printfa(name, ":fd=%d", fd);
+	}
+	if (conn->list->set.log_connection_id) {
+		if (str_len(name) == 5)
+			str_append_c(name, ':');
+		else
+			str_append_c(name, ',');
+		str_printfa(name, "id=%u", conn->id);
+	}
+	str_append_c(name, ')');
+
+	return str_c(name);
+}
+
+static void connection_update_stream_names(struct connection *conn)
+{
+	if (conn->input != NULL) {
+		i_stream_set_name(
+			conn->input,
+			connection_create_stream_name(conn, conn->fd_in));
+	}
+	if (conn->output != NULL) {
+		o_stream_set_name(
+			conn->output,
+			connection_create_stream_name(conn, conn->fd_out));
+	}
+}
+
+void connection_update_event(struct connection *conn)
+{
+	string_t *prefix;
+
+	prefix = t_str_new(64);
+	str_append(prefix, "conn");
+	if (strlen(conn->label) > 0) {
+		str_append_c(prefix, ' ');
+		str_append(prefix, conn->label);
+	}
+	str_append(prefix, ": ");
+	event_set_append_log_prefix(conn->event, str_c(prefix));
+
+	if (conn->local_ip.family > 0) {
+		event_add_str(conn->event, conn->list->set.client ?
+			      "source_ip" : "local_ip",
+			      net_ip2addr(&conn->local_ip));
+	}
+
+	if (conn->remote_ip.family > 0) {
+		event_add_str(conn->event, conn->list->set.client ?
+			      "dest_ip" : "remote_ip",
+			      net_ip2addr(&conn->remote_ip));
+	}
+	if (conn->remote_port > 0) {
+		event_add_int(conn->event, conn->list->set.client ?
+			      "dest_port" : "remote_port",
+			      conn->remote_port);
+	}
+
+	if (conn->remote_pid != (pid_t)-1)
+		event_add_int(conn->event, "remote_pid", conn->remote_pid);
+	if (conn->remote_uid != (uid_t)-1)
+		event_add_int(conn->event, "remote_uid", conn->remote_uid);
+}
+
+void connection_update_properties(struct connection *conn)
+{
+	int fd = (conn->fd_in < 0 ? conn->fd_out : conn->fd_in);
+	struct net_unix_cred cred;
+
+	if (conn->remote_ip.family != 0) {
+		/* remote IP was already set */
+	} else if (conn->unix_peer_checked) {
+		/* already checked */
+	} else if (fd < 0) {
+		/* not connected yet - wait */
+	} else {
+		if (net_getpeername(fd, &conn->remote_ip,
+				    &conn->remote_port) == 0) {
+			/* either TCP or UNIX socket connection */
+			errno = 0;
+		}
+
+		if (conn->remote_ip.family != 0) {
+			/* TCP connection */
+			i_assert(conn->remote_port != 0);
+		} else if (errno == ENOTSOCK) {
+			/* getpeername() already found out this can't be a UNIX
+			   socket connection */
+		} else if (net_getunixcred(fd, &cred) == 0) {
+			conn->remote_pid = cred.pid;
+			conn->remote_uid = cred.uid;
+		}
+		conn->unix_peer_checked = TRUE;
+	}
+
+	connection_update_property_label(conn);
+	connection_update_label(conn);
+	connection_update_stream_names(conn);
+	connection_update_event(conn);
+
+	conn->name = (conn->base_name != NULL ?
+		      conn->base_name : conn->property_label);
+}
+
+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->handshake_received = FALSE;
+	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_switch_ioloop_to(conn->input, conn->ioloop);
+	}
+	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_switch_ioloop_to(conn->output, conn->ioloop);
+	}
+	connection_update_stream_names(conn);
+
+	conn->disconnected = FALSE;
+	i_assert(conn->to == NULL);
+	connection_input_resume_full(conn, FALSE);
+	i_assert(conn->to != NULL || conn->input_idle_timeout_secs == 0);
+	if (set->major_version != 0 && !set->dont_send_version) {
+		e_debug(conn->event, "Sending version handshake");
+		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) {
+		connection_input_halt(conn);
+		connection_input_resume(conn);
+	}
+}
+
+static void connection_client_connected(struct connection *conn, bool success)
+{
+	i_assert(conn->list->set.client);
+
+	connection_update_properties(conn);
+
+	conn->connect_finished = ioloop_timeval;
+
+	struct event_passthrough *e = event_create_passthrough(conn->event)->
+		set_name("server_connection_connected");
+	if (success) {
+		e_debug(e->event(), "Client connected (fd=%d)",
+			conn->fd_in);
+	} else {
+		e_debug(e->event(), "Client connection failed (fd=%d)",
+			conn->fd_in);
+	}
+
+	if (success)
+		connection_init_streams(conn);
+	if (conn->v.client_connected != NULL)
+		conn->v.client_connected(conn, success);
+	if (!success) {
+		connection_closed(conn, CONNECTION_DISCONNECT_CONN_CLOSED);
+	}
+}
+
+static void
+connection_init_full(struct connection_list *list, struct connection *conn,
+		     const char *name, int fd_in, int fd_out)
+{
+	if (conn->id == 0) {
+		if (list->id_counter == 0)
+			list->id_counter++;
+		conn->id = list->id_counter++;
+	}
+
+	conn->ioloop = current_ioloop;
+	conn->fd_in = fd_in;
+	conn->fd_out = fd_out;
+	conn->disconnected = TRUE;
+	conn->remote_uid = (uid_t)-1;
+	conn->remote_pid = (pid_t)-1;
+
+	i_free(conn->base_name);
+	conn->base_name = i_strdup(name);
+
+	if (list->set.input_idle_timeout_secs != 0 &&
+	    conn->input_idle_timeout_secs == 0) {
+		conn->input_idle_timeout_secs =
+			list->set.input_idle_timeout_secs;
+	}
+
+	if (conn->event == NULL)
+		conn->event = event_create(conn->event_parent);
+	if (list->set.debug)
+		event_set_forced_debug(conn->event, TRUE);
+
+	if (conn->list != NULL) {
+		i_assert(conn->list == list);
+	} else {
+		conn->list = list;
+		DLLIST_PREPEND(&list->connections, conn);
+		list->connections_count++;
+	}
+
+	connection_update_properties(conn);
+	connection_set_default_handlers(conn);
+}
+
+void connection_init(struct connection_list *list, struct connection *conn,
+		     const char *name)
+{
+	connection_init_full(list, conn, name, -1, -1);
+}
+
+void connection_init_server(struct connection_list *list,
+			    struct connection *conn, const char *name,
+			    int fd_in, int fd_out)
+{
+	i_assert(!list->set.client);
+
+	connection_init_full(list, conn, name, fd_in, fd_out);
+
+	struct event_passthrough *e = event_create_passthrough(conn->event)->
+		set_name("client_connection_connected");
+	/* fd_out differs from fd_in only for stdin/stdout. Keep the logging
+	   output nice and clean by logging only the fd_in. If it's 0, it'll
+	   also be obvious that fd_out=1. */
+	e_debug(e->event(), "Server accepted connection (fd=%d)", fd_in);
+
+	connection_init_streams(conn);
+}
+
+void connection_init_server_ip(struct connection_list *list,
+			       struct connection *conn, const char *name,
+			       int fd_in, int fd_out,
+			       const struct ip_addr *remote_ip,
+			       in_port_t remote_port)
+{
+	if (remote_ip != NULL && remote_ip->family != 0)
+		conn->remote_ip = *remote_ip;
+	if (remote_port != 0)
+		conn->remote_port = remote_port;
+
+	connection_init_server(list, conn, name, fd_in, fd_out);
+}
+
+void connection_init_client_fd(struct connection_list *list,
+			       struct connection *conn, const char *name,
+			       int fd_in, int fd_out)
+{
+	i_assert(list->set.client);
+
+	connection_init_full(list, conn, name, fd_in, fd_out);
+
+	struct event_passthrough *e = event_create_passthrough(conn->event)->
+		set_name("server_connection_connected");
+	/* fd_out differs from fd_in only for stdin/stdout. Keep the logging
+	   output nice and clean by logging only the fd_in. If it's 0, it'll
+	   also be obvious that fd_out=1. */
+	e_debug(e->event(), "Client connected (fd=%d)", fd_in);
+
+	connection_client_connected(conn, TRUE);
+}
+
+void connection_init_client_ip_from(struct connection_list *list,
+				    struct connection *conn,
+				    const char *hostname,
+				    const struct ip_addr *ip, in_port_t port,
+				    const struct ip_addr *my_ip)
+{
+	const char *name = NULL;
+
+	if (hostname != NULL)
+		name = t_strdup_printf("%s:%u", hostname, port);
+
+	i_assert(list->set.client);
+
+	conn->remote_ip = *ip;
+	conn->remote_port = port;
+
+	if (my_ip != NULL)
+		conn->local_ip = *my_ip;
+	else
+		i_zero(&conn->local_ip);
+
+	connection_init(list, conn, name);
+	if (hostname != NULL)
+		event_add_str(conn->event, "dest_host", hostname);
+	connection_update_event(conn);
+}
+
+void connection_init_client_ip(struct connection_list *list,
+			       struct connection *conn, const char *hostname,
+			       const struct ip_addr *ip, in_port_t port)
+{
+	connection_init_client_ip_from(list, conn, hostname, ip, port, NULL);
+}
+
+void connection_init_client_unix(struct connection_list *list,
+				 struct connection *conn, const char *path)
+{
+	i_assert(list->set.client);
+
+	conn->unix_socket = TRUE;
+
+	connection_init(list, conn, path);
+	event_add_str(conn->event, "socket_path", path);
+}
+
+void connection_init_from_streams(struct connection_list *list,
+				  struct connection *conn, const char *name,
+				  struct istream *input, struct ostream *output)
+{
+	connection_init_full(list, conn, name,
+			     i_stream_get_fd(input), 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);
+
+	conn->output = output;
+	o_stream_ref(conn->output);
+	o_stream_set_no_error_handling(conn->output, TRUE);
+
+	connection_update_stream_names(conn);
+	
+	conn->disconnected = FALSE;
+	connection_input_resume_full(conn, FALSE);
+
+	if (conn->v.client_connected != NULL)
+		conn->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);
+
+	e_debug(conn->event, "Connecting");
+
+	if (conn->remote_port != 0) {
+		fd = net_connect_ip(&conn->remote_ip, conn->remote_port,
+				    (conn->local_ip.family != 0 ?
+				     &conn->local_ip : NULL));
+	} else if (conn->list->set.unix_client_connect_msecs == 0) {
+		fd = net_connect_unix(conn->base_name);
+	} else {
+		fd = net_connect_unix_with_retries(
+			conn->base_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;
+	conn->disconnected = FALSE;
+
+	if (conn->remote_port != 0 ||
+	    conn->list->set.delayed_unix_client_connected_callback) {
+		connection_update_properties(conn);
+		conn->io = io_add_to(conn->ioloop, conn->fd_out, IO_WRITE,
+				     connection_socket_connected, conn);
+		e_debug(conn->event,
+			"Waiting for connect (fd=%d) to finish for max %u msecs",
+			fd, set->client_connect_timeout_msecs);
+		if (set->client_connect_timeout_msecs != 0) {
+			conn->to = timeout_add_to(conn->ioloop,
+						  set->client_connect_timeout_msecs,
+						  *conn->v.connect_timeout, conn);
+		}
+	} else {
+		connection_client_connected(conn, TRUE);
+	}
+	return 0;
+}
+
+static void connection_update_counters(struct connection *conn)
+{
+	if (conn->input != NULL)
+		event_add_int(conn->event, "bytes_in", conn->input->v_offset);
+	if (conn->output != NULL)
+		event_add_int(conn->event, "bytes_out", conn->output->offset);
+}
+
+void connection_disconnect(struct connection *conn)
+{
+	if (conn->disconnected)
+		return;
+	connection_update_counters(conn);
+	/* client connects to a Server, and Server gets connection from Client
+	 */
+	const char *ename = conn->list->set.client ?
+		"server_connection_disconnected" :
+		"client_connection_disconnected";
+
+	struct event_passthrough *e = event_create_passthrough(conn->event)->
+		set_name(ename)->
+		add_str("reason", connection_disconnect_reason(conn));
+	e_debug(e->event(), "Disconnected: %s (fd=%d)",
+		connection_disconnect_reason(conn), conn->fd_in);
+
+	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);
+	conn->disconnected = TRUE;
+}
+
+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->base_name);
+	i_free(conn->label);
+	i_free(conn->property_label);
+	event_unref(&conn->event);
+	conn->list = NULL;
+}
+
+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:
+			connection_closed(conn,
+					  CONNECTION_DISCONNECT_BUFFER_FULL);
+			return -1;
+		case CONNECTION_BEHAVIOR_ALLOW:
+			return -2;
+		}
+		i_unreached();
+	case -1:
+		/* disconnected */
+		connection_closed(conn, CONNECTION_DISCONNECT_CONN_CLOSED);
+		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);
+	case CONNECTION_DISCONNECT_HANDSHAKE_FAILED:
+		return "Handshake failed";
+	}
+	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_set_handlers(struct connection *conn,
+			     const struct connection_vfuncs *vfuncs)
+{
+	connection_input_halt(conn);
+	i_assert(vfuncs->destroy != NULL);
+	conn->v = *vfuncs;
+        if (conn->v.input == NULL)
+                conn->v.input = connection_input_default;
+        if (conn->v.input_line == NULL)
+                conn->v.input_line = connection_input_line_default;
+        if (conn->v.handshake_args == NULL)
+                conn->v.handshake_args = connection_handshake_args_default;
+        if (conn->v.idle_timeout == NULL)
+                conn->v.idle_timeout = connection_idle_timeout;
+        if (conn->v.connect_timeout == NULL)
+                conn->v.connect_timeout = connection_connect_timeout;
+	if (!conn->disconnected)
+		connection_input_resume_full(conn, FALSE);
+}
+
+void connection_set_default_handlers(struct connection *conn)
+{
+	connection_set_handlers(conn, &conn->list->v);
+}
+
+void connection_switch_ioloop_to(struct connection *conn,
+				 struct ioloop *ioloop)
+{
+	conn->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;
+
+	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;
+		connection_closed(conn, CONNECTION_DISCONNECT_DEINIT);
+		i_assert(conn != list->connections);
+	}
+	i_free(list);
+}