Adding upstream version 1:2.3.19.1+dfsg1.upstream/1%2.3.19.1+dfsg1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1656 insertions, 0 deletions

diff --git a/src/lib-smtp/smtp-client-transaction.c b/src/lib-smtp/smtp-client-transaction.c
new file mode 100644
index 0000000..0112021
--- /dev/null
+++ b/src/lib-smtp/smtp-client-transaction.c
@@ -0,0 +1,1656 @@
+/* Copyright (c) 2009-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "llist.h"
+#include "ioloop.h"
+#include "net.h"
+#include "istream.h"
+#include "istream-crlf.h"
+#include "ostream.h"
+#include "str.h"
+#include "str-sanitize.h"
+#include "dns-lookup.h"
+
+#include "smtp-common.h"
+#include "smtp-address.h"
+#include "smtp-params.h"
+#include "smtp-client-private.h"
+#include "smtp-client-command.h"
+#include "smtp-client-transaction.h"
+
+#include <ctype.h>
+
+const char *const smtp_client_transaction_state_names[] = {
+	"new",
+	"pending",
+	"mail_from",
+	"rcpt_to",
+	"data",
+	"reset",
+	"finished",
+	"aborted"
+};
+
+static void
+smtp_client_transaction_submit_more(struct smtp_client_transaction *trans);
+static void
+smtp_client_transaction_submit(struct smtp_client_transaction *trans,
+			       bool start);
+
+static void
+smtp_client_transaction_try_complete(struct smtp_client_transaction *trans);
+
+static void
+smtp_client_transaction_send_data(struct smtp_client_transaction *trans);
+static void
+smtp_client_transaction_send_reset(struct smtp_client_transaction *trans);
+
+/*
+ * Sender
+ */
+
+static struct smtp_client_transaction_mail *
+smtp_client_transaction_mail_new(struct smtp_client_transaction *trans,
+				 const struct smtp_address *mail_from,
+				 const struct smtp_params_mail *mail_params)
+{
+	struct smtp_client_transaction_mail *mail;
+	pool_t pool;
+
+	pool = pool_alloconly_create("smtp transaction mail", 512);
+	mail = p_new(pool, struct smtp_client_transaction_mail, 1);
+	mail->pool = pool;
+	mail->trans = trans;
+	mail->mail_from = smtp_address_clone(pool, mail_from);
+	smtp_params_mail_copy(pool, &mail->mail_params, mail_params);
+
+	DLLIST2_APPEND(&trans->mail_head, &trans->mail_tail, mail);
+	if (trans->mail_send == NULL)
+		trans->mail_send = mail;
+
+	return mail;
+}
+
+static void
+smtp_client_transaction_mail_free(struct smtp_client_transaction_mail **_mail)
+{
+	struct smtp_client_transaction_mail *mail = *_mail;
+
+	if (mail == NULL)
+		return;
+	*_mail = NULL;
+
+	struct smtp_client_transaction *trans = mail->trans;
+
+	if (mail->cmd_mail_from != NULL)
+		smtp_client_command_abort(&mail->cmd_mail_from);
+	DLLIST2_REMOVE(&trans->mail_head, &trans->mail_tail, mail);
+	pool_unref(&mail->pool);
+}
+
+static void
+smtp_client_transaction_mail_replied(
+	struct smtp_client_transaction_mail **_mail,
+	const struct smtp_reply *reply)
+{
+	struct smtp_client_transaction_mail *mail = *_mail;
+
+	if (mail == NULL)
+		return;
+	*_mail = NULL;
+
+	smtp_client_command_callback_t *mail_callback = mail->mail_callback;
+	void *context = mail->context;
+
+	mail->mail_callback = NULL;
+	smtp_client_transaction_mail_free(&mail);
+
+	/* Call the callback */
+	if (mail_callback != NULL)
+		mail_callback(reply, context);
+}
+
+void smtp_client_transaction_mail_abort(
+	struct smtp_client_transaction_mail **_mail)
+{
+	struct smtp_client_transaction_mail *mail = *_mail;
+
+	if (mail == NULL)
+		return;
+	*_mail = NULL;
+
+	struct smtp_client_transaction *trans = mail->trans;
+
+	i_assert(trans->state <= SMTP_CLIENT_TRANSACTION_STATE_MAIL_FROM ||
+		 trans->state == SMTP_CLIENT_TRANSACTION_STATE_ABORTED);
+
+	smtp_client_transaction_mail_free(&mail);
+}
+
+static void
+smtp_client_transaction_mail_fail_reply(
+	struct smtp_client_transaction_mail **_mail,
+	const struct smtp_reply *reply)
+{
+	struct smtp_client_transaction_mail *mail = *_mail;
+
+	if (mail == NULL)
+		return;
+	*_mail = NULL;
+
+	smtp_client_command_callback_t *callback = mail->mail_callback;
+	void *context = mail->context;
+
+	mail->mail_callback = NULL;
+	smtp_client_transaction_mail_free(&mail);
+
+	if (callback != NULL)
+		callback(reply, context);
+}
+
+/*
+ * Recipient
+ */
+
+static void
+smtp_client_transaction_rcpt_update_event(
+	struct smtp_client_transaction_rcpt *rcpt)
+{
+	const char *to = smtp_address_encode(rcpt->rcpt_to);
+
+	event_set_append_log_prefix(rcpt->event,
+				    t_strdup_printf("rcpt <%s>: ",
+						    str_sanitize(to, 128)));
+	event_add_str(rcpt->event, "rcpt_to", to);
+	smtp_params_rcpt_add_to_event(&rcpt->rcpt_params, rcpt->event);
+}
+
+static struct smtp_client_transaction_rcpt *
+smtp_client_transaction_rcpt_new(struct smtp_client_transaction *trans,
+				 pool_t pool,
+				 const struct smtp_address *rcpt_to,
+				 const struct smtp_params_rcpt *rcpt_params)
+{
+	struct smtp_client_transaction_rcpt *rcpt;
+
+	pool_ref(pool);
+
+	rcpt = p_new(pool, struct smtp_client_transaction_rcpt, 1);
+	rcpt->pool = pool;
+	rcpt->trans = trans;
+	rcpt->rcpt_to = smtp_address_clone(pool, rcpt_to);
+	smtp_params_rcpt_copy(pool, &rcpt->rcpt_params, rcpt_params);
+
+	DLLIST2_APPEND(&trans->rcpts_queue_head, &trans->rcpts_queue_tail,
+		       rcpt);
+	trans->rcpts_queue_count++;
+	rcpt->queued = TRUE;
+	if (trans->rcpts_send == NULL)
+		trans->rcpts_send = rcpt;
+
+	rcpt->event = event_create(trans->event);
+	smtp_client_transaction_rcpt_update_event(rcpt);
+
+	trans->rcpts_total++;
+
+	return rcpt;
+}
+
+static void
+smtp_client_transaction_rcpt_free(
+	struct smtp_client_transaction_rcpt **_rcpt)
+{
+	struct smtp_client_transaction_rcpt *rcpt = *_rcpt;
+
+	if (rcpt == NULL)
+		return;
+	*_rcpt = NULL;
+
+	struct smtp_client_transaction *trans = rcpt->trans;
+
+	smtp_client_command_abort(&rcpt->cmd_rcpt_to);
+	if (trans->rcpts_send == rcpt)
+		trans->rcpts_send = rcpt->next;
+	if (trans->rcpts_data == rcpt)
+		trans->rcpts_data = rcpt->next;
+	if (rcpt->queued) {
+		DLLIST2_REMOVE(&trans->rcpts_queue_head,
+			       &trans->rcpts_queue_tail, rcpt);
+		trans->rcpts_queue_count--;
+	} else {
+		DLLIST2_REMOVE(&trans->rcpts_head,
+			       &trans->rcpts_tail, rcpt);
+		trans->rcpts_count--;
+	}
+
+	if (!rcpt->finished) {
+		struct smtp_reply failure;
+
+		trans->rcpts_aborted++;
+
+		smtp_reply_init(&failure,
+				SMTP_CLIENT_COMMAND_ERROR_ABORTED, "Aborted");
+		failure.enhanced_code = SMTP_REPLY_ENH_CODE(9, 0, 0);
+
+		struct event_passthrough *e =
+			event_create_passthrough(rcpt->event)->
+			set_name("smtp_client_transaction_rcpt_finished");
+		smtp_reply_add_to_event(&failure, e);
+		e_debug(e->event(), "Aborted");
+	}
+
+	event_unref(&rcpt->event);
+
+	if (rcpt->queued || rcpt->external_pool) {
+		i_assert(rcpt->pool != NULL);
+		pool_unref(&rcpt->pool);
+	}
+}
+
+static void
+smtp_client_transaction_rcpt_approved(
+	struct smtp_client_transaction_rcpt **_rcpt)
+{
+	struct smtp_client_transaction_rcpt *prcpt = *_rcpt;
+
+	i_assert(prcpt != NULL);
+
+	struct smtp_client_transaction *trans = prcpt->trans;
+	struct smtp_client_transaction_rcpt *rcpt;
+	pool_t pool;
+
+	i_assert(prcpt->queued);
+
+	if (prcpt->external_pool) {
+		/* Allocated externally; just remove it from the queue */
+		prcpt->queued = FALSE;
+		if (trans->rcpts_send == prcpt)
+			trans->rcpts_send = prcpt->next;
+		DLLIST2_REMOVE(&trans->rcpts_queue_head,
+			       &trans->rcpts_queue_tail, prcpt);
+		trans->rcpts_queue_count--;
+
+		rcpt = prcpt;
+	} else {
+		/* Move to transaction pool */
+		pool = trans->pool;
+		rcpt = p_new(pool, struct smtp_client_transaction_rcpt, 1);
+		rcpt->trans = trans;
+		rcpt->rcpt_to = smtp_address_clone(pool, prcpt->rcpt_to);
+		smtp_params_rcpt_copy(pool, &rcpt->rcpt_params,
+				      &prcpt->rcpt_params);
+		rcpt->data_callback = prcpt->data_callback;
+		rcpt->data_context = prcpt->data_context;
+
+		rcpt->event = prcpt->event;
+		event_ref(rcpt->event);
+
+		/* Free the old object, thereby removing it from the queue */
+		smtp_client_transaction_rcpt_free(&prcpt);
+	}
+
+	/* Recipient is approved */
+	DLLIST2_APPEND(&trans->rcpts_head, &trans->rcpts_tail, rcpt);
+	trans->rcpts_count++;
+	if (trans->rcpts_data == NULL)
+		trans->rcpts_data = trans->rcpts_head;
+
+	*_rcpt = rcpt;
+}
+
+static void
+smtp_client_transaction_rcpt_denied(
+	struct smtp_client_transaction_rcpt **_rcpt,
+	const struct smtp_reply *reply)
+{
+	struct smtp_client_transaction_rcpt *prcpt = *_rcpt;
+
+	*_rcpt = NULL;
+	i_assert(prcpt != NULL);
+
+	struct smtp_client_transaction *trans = prcpt->trans;
+
+	trans->rcpts_denied++;
+	trans->rcpts_failed++;
+
+	struct event_passthrough *e =
+		event_create_passthrough(prcpt->event)->
+		set_name("smtp_client_transaction_rcpt_finished");
+	smtp_reply_add_to_event(reply, e);
+	e_debug(e->event(), "Denied");
+
+	/* Not pending anymore */
+	smtp_client_transaction_rcpt_free(&prcpt);
+}
+
+static void
+smtp_client_transaction_rcpt_replied(
+	struct smtp_client_transaction_rcpt **_rcpt,
+	const struct smtp_reply *reply)
+{
+	struct smtp_client_transaction_rcpt *rcpt = *_rcpt;
+
+	*_rcpt = NULL;
+	if (rcpt == NULL)
+		return;
+
+	bool success = smtp_reply_is_success(reply);
+	smtp_client_command_callback_t *rcpt_callback = rcpt->rcpt_callback;
+	void *context = rcpt->context;
+
+	rcpt->rcpt_callback = NULL;
+
+	if (rcpt->finished)
+		return;
+	rcpt->finished = !success;
+
+	if (success)
+		smtp_client_transaction_rcpt_approved(&rcpt);
+	else
+		smtp_client_transaction_rcpt_denied(&rcpt, reply);
+
+	/* Call the callback */
+	if (rcpt_callback != NULL)
+		rcpt_callback(reply, context);
+}
+
+void smtp_client_transaction_rcpt_abort(
+	struct smtp_client_transaction_rcpt **_rcpt)
+{
+	struct smtp_client_transaction_rcpt *rcpt = *_rcpt;
+
+	if (rcpt == NULL)
+		return;
+	*_rcpt = NULL;
+
+	struct smtp_client_transaction *trans = rcpt->trans;
+
+	i_assert(rcpt->queued || rcpt->external_pool);
+
+	i_assert(trans->state <= SMTP_CLIENT_TRANSACTION_STATE_RCPT_TO ||
+		 trans->state == SMTP_CLIENT_TRANSACTION_STATE_ABORTED);
+
+	smtp_client_transaction_rcpt_free(&rcpt);
+}
+
+static void
+smtp_client_transaction_rcpt_fail_reply(
+	struct smtp_client_transaction_rcpt **_rcpt,
+	const struct smtp_reply *reply)
+{
+	struct smtp_client_transaction_rcpt *rcpt = *_rcpt;
+
+	if (rcpt == NULL)
+		return;
+	*_rcpt = NULL;
+
+	struct smtp_client_transaction *trans = rcpt->trans;
+	smtp_client_command_callback_t *callback;
+	void *context;
+
+	if (rcpt->finished)
+		return;
+	rcpt->finished = TRUE;
+
+	trans->rcpts_failed++;
+
+	if (rcpt->queued) {
+		callback = rcpt->rcpt_callback;
+		context = rcpt->context;
+	} else {
+		callback = rcpt->data_callback;
+		context = rcpt->data_context;
+	}
+	rcpt->rcpt_callback = NULL;
+	rcpt->data_callback = NULL;
+
+	struct event_passthrough *e =
+		event_create_passthrough(rcpt->event)->
+		set_name("smtp_client_transaction_rcpt_finished");
+	smtp_reply_add_to_event(reply, e);
+	e_debug(e->event(), "Failed");
+
+	smtp_client_transaction_rcpt_free(&rcpt);
+
+	if (callback != NULL)
+		callback(reply, context);
+}
+
+static void
+smtp_client_transaction_rcpt_finished(struct smtp_client_transaction_rcpt *rcpt,
+				      const struct smtp_reply *reply)
+{
+	struct smtp_client_transaction *trans = rcpt->trans;
+
+	i_assert(!rcpt->finished);
+	rcpt->finished = TRUE;
+
+	if (smtp_reply_is_success(reply))
+		trans->rcpts_succeeded++;
+	else
+		trans->rcpts_failed++;
+
+	struct event_passthrough *e =
+		event_create_passthrough(rcpt->event)->
+		set_name("smtp_client_transaction_rcpt_finished");
+	smtp_reply_add_to_event(reply, e);
+	e_debug(e->event(), "Finished");
+
+	if (rcpt->data_callback != NULL)
+		rcpt->data_callback(reply, rcpt->data_context);
+	rcpt->data_callback = NULL;
+}
+
+#undef smtp_client_transaction_rcpt_set_data_callback
+void smtp_client_transaction_rcpt_set_data_callback(
+	struct smtp_client_transaction_rcpt *rcpt,
+	smtp_client_command_callback_t *callback, void *context)
+{
+	i_assert(!rcpt->finished);
+
+	rcpt->data_callback = callback;
+	rcpt->data_context = context;
+}
+
+/*
+ * Transaction
+ */
+
+static void
+smtp_client_transaction_update_event(struct smtp_client_transaction *trans)
+{
+	event_set_append_log_prefix(trans->event, "transaction: ");
+}
+
+static struct event_passthrough *
+smtp_client_transaction_result_event(struct smtp_client_transaction *trans,
+				     const struct smtp_reply *reply)
+{
+	struct event_passthrough *e;
+	unsigned int rcpts_aborted = (trans->rcpts_aborted +
+				      trans->rcpts_queue_count);
+
+	e = event_create_passthrough(trans->event)->
+		set_name("smtp_client_transaction_finished")->
+		add_int("recipients", trans->rcpts_total)->
+		add_int("recipients_aborted", rcpts_aborted)->
+		add_int("recipients_denied", trans->rcpts_denied)->
+		add_int("recipients_failed", trans->rcpts_failed)->
+		add_int("recipients_succeeded", trans->rcpts_succeeded);
+
+	smtp_reply_add_to_event(reply, e);
+	if (trans->reset)
+		e->add_str("is_reset", "yes");
+	return e;
+}
+
+#undef smtp_client_transaction_create_empty
+struct smtp_client_transaction *
+smtp_client_transaction_create_empty(
+	struct smtp_client_connection *conn,
+	enum smtp_client_transaction_flags flags,
+	smtp_client_transaction_callback_t *callback, void *context)
+{
+	struct smtp_client_transaction *trans;
+	pool_t pool;
+
+	if (conn->protocol == SMTP_PROTOCOL_LMTP)
+		flags |= SMTP_CLIENT_TRANSACTION_FLAG_REPLY_PER_RCPT;
+
+	pool = pool_alloconly_create("smtp transaction", 4096);
+	trans = p_new(pool, struct smtp_client_transaction, 1);
+	trans->refcount = 1;
+	trans->pool = pool;
+	trans->flags = flags;
+	trans->callback = callback;
+	trans->context = context;
+
+	trans->event = event_create(conn->event);
+	smtp_client_transaction_update_event(trans);
+
+	trans->conn = conn;
+	smtp_client_connection_ref(conn);
+
+	e_debug(trans->event, "Created");
+
+	return trans;
+}
+
+#undef smtp_client_transaction_create
+struct smtp_client_transaction *
+smtp_client_transaction_create(struct smtp_client_connection *conn,
+			       const struct smtp_address *mail_from,
+			       const struct smtp_params_mail *mail_params,
+			       enum smtp_client_transaction_flags flags,
+			       smtp_client_transaction_callback_t *callback,
+			       void *context)
+{
+	struct smtp_client_transaction *trans;
+
+	trans = smtp_client_transaction_create_empty(conn, flags,
+						     callback, context);
+	(void)smtp_client_transaction_mail_new(trans, mail_from, mail_params);
+	return trans;
+}
+
+static void
+smtp_client_transaction_finish(struct smtp_client_transaction *trans,
+			       const struct smtp_reply *final_reply)
+{
+	struct smtp_client_connection *conn = trans->conn;
+
+	if (trans->state >= SMTP_CLIENT_TRANSACTION_STATE_FINISHED)
+		return;
+
+	timeout_remove(&trans->to_finish);
+
+	struct event_passthrough *e =
+		smtp_client_transaction_result_event(trans, final_reply);
+	e_debug(e->event(), "Finished");
+
+	io_loop_time_refresh();
+	trans->times.finished = ioloop_timeval;
+
+	i_assert(trans->to_send == NULL);
+
+	trans->state = SMTP_CLIENT_TRANSACTION_STATE_FINISHED;
+	i_assert(trans->callback != NULL);
+	trans->callback(trans->context);
+
+	if (!trans->submitted_data)
+		smtp_client_connection_abort_transaction(conn, trans);
+
+	smtp_client_transaction_unref(&trans);
+}
+
+void smtp_client_transaction_abort(struct smtp_client_transaction *trans)
+{
+	struct smtp_client_connection *conn = trans->conn;
+
+	if (trans->failing) {
+		e_debug(trans->event, "Abort (already failing)");
+		return;
+	}
+
+	e_debug(trans->event, "Abort");
+
+	/* Clean up */
+	i_stream_unref(&trans->data_input);
+	timeout_remove(&trans->to_send);
+	timeout_remove(&trans->to_finish);
+
+	trans->cmd_last = NULL;
+
+	/* Abort any pending commands */
+	while (trans->mail_head != NULL) {
+		struct smtp_client_transaction_mail *mail = trans->mail_head;
+
+		smtp_client_transaction_mail_free(&mail);
+	}
+	while (trans->rcpts_queue_count > 0) {
+		struct smtp_client_transaction_rcpt *rcpt =
+			trans->rcpts_queue_head;
+
+		smtp_client_transaction_rcpt_free(&rcpt);
+	}
+	if (trans->cmd_data != NULL)
+		smtp_client_command_abort(&trans->cmd_data);
+	if (trans->cmd_rset != NULL)
+		smtp_client_command_abort(&trans->cmd_rset);
+	if (trans->cmd_plug != NULL)
+		smtp_client_command_abort(&trans->cmd_plug);
+	trans->cmd_data = NULL;
+	trans->cmd_rset = NULL;
+	trans->cmd_plug = NULL;
+
+	smtp_client_connection_abort_transaction(conn, trans);
+
+	/* Abort if not finished */
+	if (trans->state < SMTP_CLIENT_TRANSACTION_STATE_FINISHED) {
+		struct event_passthrough *e;
+
+		if (trans->failure != NULL) {
+			e = smtp_client_transaction_result_event(
+				trans, trans->failure);
+			e_debug(e->event(), "Failed");
+		} else {
+			struct smtp_reply failure;
+
+			smtp_reply_init(&failure,
+					SMTP_CLIENT_COMMAND_ERROR_ABORTED,
+					"Aborted");
+			failure.enhanced_code = SMTP_REPLY_ENH_CODE(9, 0, 0);
+
+			e = smtp_client_transaction_result_event(
+				trans, &failure);
+			e_debug(e->event(), "Aborted");
+		}
+
+		trans->state = SMTP_CLIENT_TRANSACTION_STATE_ABORTED;
+		i_assert(trans->callback != NULL);
+		trans->callback(trans->context);
+
+		smtp_client_transaction_unref(&trans);
+	}
+}
+
+void smtp_client_transaction_ref(struct smtp_client_transaction *trans)
+{
+	trans->refcount++;
+}
+
+void smtp_client_transaction_unref(struct smtp_client_transaction **_trans)
+{
+	struct smtp_client_transaction *trans = *_trans;
+	struct smtp_client_connection *conn;
+
+	*_trans = NULL;
+
+	if (trans == NULL)
+		return;
+	conn = trans->conn;
+
+	i_assert(trans->refcount > 0);
+	if (--trans->refcount > 0)
+		return;
+
+	e_debug(trans->event, "Destroy");
+
+	i_stream_unref(&trans->data_input);
+	smtp_client_transaction_abort(trans);
+
+	while (trans->rcpts_count > 0) {
+		struct smtp_client_transaction_rcpt *rcpt =
+			trans->rcpts_head;
+		smtp_client_transaction_rcpt_free(&rcpt);
+	}
+
+	i_assert(trans->state >= SMTP_CLIENT_TRANSACTION_STATE_FINISHED);
+	event_unref(&trans->event);
+	pool_unref(&trans->pool);
+
+	smtp_client_connection_unref(&conn);
+}
+
+void smtp_client_transaction_destroy(struct smtp_client_transaction **_trans)
+{
+	struct smtp_client_transaction *trans = *_trans;
+	struct smtp_client_transaction_mail *mail;
+	struct smtp_client_transaction_rcpt *rcpt;
+
+	*_trans = NULL;
+
+	if (trans == NULL)
+		return;
+
+	smtp_client_transaction_ref(trans);
+	smtp_client_transaction_abort(trans);
+
+	/* Make sure this transaction doesn't produce any more callbacks.
+	   We cannot fully abort (destroy) these commands, as this may be
+	   called from a callback. */
+	for (mail = trans->mail_head; mail != NULL; mail = mail->next) {
+		if (mail->cmd_mail_from != NULL)
+			smtp_client_command_drop_callback(mail->cmd_mail_from);
+	}
+	for (rcpt = trans->rcpts_queue_head; rcpt != NULL; rcpt = rcpt->next) {
+		if (rcpt->cmd_rcpt_to != NULL)
+			smtp_client_command_drop_callback(rcpt->cmd_rcpt_to);
+	}
+	if (trans->cmd_data != NULL)
+		smtp_client_command_drop_callback(trans->cmd_data);
+	if (trans->cmd_rset != NULL)
+		smtp_client_command_drop_callback(trans->cmd_rset);
+	if (trans->cmd_plug != NULL)
+		smtp_client_command_abort(&trans->cmd_plug);
+
+	/* Free any approved recipients early */
+	while (trans->rcpts_count > 0) {
+		struct smtp_client_transaction_rcpt *rcpt =
+			trans->rcpts_head;
+		smtp_client_transaction_rcpt_free(&rcpt);
+	}
+
+	if (trans->state < SMTP_CLIENT_TRANSACTION_STATE_FINISHED) {
+		struct smtp_client_transaction *trans_tmp = trans;
+
+		trans->state = SMTP_CLIENT_TRANSACTION_STATE_ABORTED;
+		smtp_client_transaction_unref(&trans_tmp);
+	}
+
+	smtp_client_transaction_unref(&trans);
+}
+
+void smtp_client_transaction_fail_reply(struct smtp_client_transaction *trans,
+					const struct smtp_reply *reply)
+{
+	struct smtp_client_transaction_rcpt *rcpt, *rcpt_next;
+
+	if (reply == NULL)
+		reply = trans->failure;
+	i_assert(reply != NULL);
+
+	if (trans->failing) {
+		e_debug(trans->event, "Already failing: %s",
+			smtp_reply_log(reply));
+		return;
+	}
+	trans->failing = TRUE;
+
+	e_debug(trans->event, "Returning failure: %s", smtp_reply_log(reply));
+
+	/* Hold a reference to prevent early destruction in a callback */
+	smtp_client_transaction_ref(trans);
+
+	trans->cmd_last = NULL;
+
+	timeout_remove(&trans->to_send);
+
+	/* MAIL */
+	while (trans->mail_head != NULL) {
+		struct smtp_client_transaction_mail *mail = trans->mail_head;
+
+		smtp_client_transaction_mail_fail_reply(&mail, reply);
+	}
+
+	/* RCPT */
+	rcpt = trans->rcpts_queue_head;
+	while (rcpt != NULL) {
+		struct smtp_client_command *cmd = rcpt->cmd_rcpt_to;
+
+		rcpt_next = rcpt->next;
+
+		rcpt->cmd_rcpt_to = NULL;
+		if (cmd != NULL)
+			smtp_client_command_fail_reply(&cmd, reply);
+		else
+			smtp_client_transaction_rcpt_fail_reply(&rcpt, reply);
+
+		rcpt = rcpt_next;
+	}
+
+	/* DATA / RSET */
+	if (!trans->data_provided && !trans->reset) {
+		/* None of smtp_client_transaction_send() and
+		   smtp_client_transaction_reset() was called so far
+		 */
+	} else if (trans->cmd_data != NULL) {
+		/* The DATA command is still pending; handle the failure by
+		   failing the DATA command. */
+		smtp_client_command_fail_reply(&trans->cmd_data, reply);
+	} else if (trans->cmd_rset != NULL) {
+		/* The RSET command is still pending; handle the failure by
+		   failing the RSET command. */
+		smtp_client_command_fail_reply(&trans->cmd_rset, reply);
+	} else {
+		i_assert(!trans->reset);
+
+		/* The DATA command was not sent yet; call all DATA callbacks
+		   for the recipients that were previously accepted. */
+		rcpt = trans->rcpts_data;
+		while (rcpt != NULL) {
+			rcpt_next = rcpt->next;
+			smtp_client_transaction_rcpt_fail_reply(&rcpt, reply);
+			rcpt = rcpt_next;
+		}
+		if (trans->data_callback != NULL)
+			trans->data_callback(reply, trans->data_context);
+		trans->data_callback = NULL;
+	}
+
+	/* Plug */
+	if (trans->failure == NULL)
+		trans->failure = smtp_reply_clone(trans->pool, reply);
+	if (trans->cmd_plug != NULL)
+		smtp_client_command_abort(&trans->cmd_plug);
+	trans->cmd_plug = NULL;
+
+	trans->failing = FALSE;
+
+	if (trans->data_provided || trans->reset) {
+		/* Abort the transaction only if smtp_client_transaction_send()
+		   or  smtp_client_transaction_reset() was called (and if it is
+		   not aborted already) */
+		smtp_client_transaction_abort(trans);
+	}
+
+	/* Drop reference held earlier in this function */
+	smtp_client_transaction_unref(&trans);
+}
+
+void smtp_client_transaction_fail(struct smtp_client_transaction *trans,
+				  unsigned int status, const char *error)
+{
+	struct smtp_reply reply;
+
+	smtp_reply_init(&reply, status, error);
+	smtp_client_transaction_fail_reply(trans, &reply);
+}
+
+void smtp_client_transaction_set_event(struct smtp_client_transaction *trans,
+				       struct event *event)
+{
+	i_assert(trans->conn != NULL);
+	event_unref(&trans->event);
+	trans->event = event_create(event);
+	event_set_forced_debug(trans->event, trans->conn->set.debug);
+	smtp_client_transaction_update_event(trans);
+}
+
+static void
+smtp_client_transaction_timeout(struct smtp_client_transaction *trans)
+{
+	struct smtp_reply reply;
+
+	smtp_reply_printf(
+		&reply, 451, "Remote server not answering "
+		"(transaction timed out while %s)",
+		smtp_client_transaction_get_state_destription(trans));
+	reply.enhanced_code = SMTP_REPLY_ENH_CODE(4, 4, 0);
+
+	smtp_client_transaction_fail_reply(trans, &reply);
+}
+
+void smtp_client_transaction_set_timeout(struct smtp_client_transaction *trans,
+					 unsigned int timeout_msecs)
+{
+	i_assert(trans->state < SMTP_CLIENT_TRANSACTION_STATE_FINISHED);
+
+	trans->finish_timeout_msecs = timeout_msecs;
+
+	if (trans->data_input != NULL && timeout_msecs > 0) {
+		/* Adjust timeout if it is already started */
+		timeout_remove(&trans->to_finish);
+		trans->to_finish = timeout_add(trans->finish_timeout_msecs,
+					       smtp_client_transaction_timeout,
+					       trans);
+	}
+}
+
+static void
+smtp_client_transaction_mail_cb(const struct smtp_reply *reply,
+				struct smtp_client_transaction *trans)
+{
+	struct smtp_client_transaction_mail *mail = trans->mail_head;
+	bool success = smtp_reply_is_success(reply);
+
+	e_debug(trans->event, "Got MAIL reply: %s", smtp_reply_log(reply));
+
+	i_assert(mail != NULL);
+	i_assert(trans->conn != NULL);
+
+	if (success) {
+		if (trans->sender_accepted) {
+			smtp_client_transaction_fail(
+				trans, SMTP_CLIENT_COMMAND_ERROR_BAD_REPLY,
+				"Server accepted more than a single MAIL command.");
+			return;
+		}
+		trans->mail_failure = NULL;
+		trans->sender_accepted = TRUE;
+	}
+
+	/* Plug command line pipeline if no RCPT commands are yet issued */
+	if (!trans->immediate && mail->next == NULL &&
+	    mail->cmd_mail_from == trans->cmd_last) {
+		trans->cmd_plug = trans->cmd_last =
+			smtp_client_command_plug(trans->conn, trans->cmd_last);
+	}
+	mail->cmd_mail_from = NULL;
+
+	if (trans->rcpts_queue_count > 0)
+		trans->state = SMTP_CLIENT_TRANSACTION_STATE_RCPT_TO;
+	else if (trans->reset)
+		trans->state = SMTP_CLIENT_TRANSACTION_STATE_RESET;
+
+	{
+		enum smtp_client_transaction_state state;
+		struct smtp_client_transaction *tmp_trans = trans;
+
+		smtp_client_transaction_ref(tmp_trans);
+
+		smtp_client_transaction_mail_replied(&mail, reply);
+
+		state = trans->state;
+		smtp_client_transaction_unref(&tmp_trans);
+		if (state >= SMTP_CLIENT_TRANSACTION_STATE_FINISHED)
+			return;
+	}
+
+	if (!trans->sender_accepted && trans->mail_head != NULL) {
+		/* Update transaction with next MAIL command candidate */
+		mail = trans->mail_head;
+		event_add_str(trans->event, "mail_from",
+			      smtp_address_encode(mail->mail_from));
+		smtp_params_mail_add_to_event(&mail->mail_params,
+					      trans->event);
+	}
+
+	if (!success && !trans->sender_accepted) {
+		if (trans->state > SMTP_CLIENT_TRANSACTION_STATE_MAIL_FROM)
+			smtp_client_transaction_fail_reply(trans, reply);
+		else if (trans->mail_failure == NULL) {
+			trans->mail_failure =
+				smtp_reply_clone(trans->pool, reply);
+		}
+	}
+}
+
+#undef smtp_client_transaction_add_mail
+struct smtp_client_transaction_mail *
+smtp_client_transaction_add_mail(struct smtp_client_transaction *trans,
+				 const struct smtp_address *mail_from,
+				 const struct smtp_params_mail *mail_params,
+				 smtp_client_command_callback_t *mail_callback,
+				 void *context)
+{
+	struct smtp_client_transaction_mail *mail;
+
+	e_debug(trans->event, "Add MAIL command");
+
+	i_assert(!trans->data_provided);
+	i_assert(!trans->reset);
+
+	i_assert(trans->state < SMTP_CLIENT_TRANSACTION_STATE_RCPT_TO);
+
+	mail = smtp_client_transaction_mail_new(trans, mail_from, mail_params);
+	mail->mail_callback = mail_callback;
+	mail->context = context;
+
+	smtp_client_transaction_submit(trans, FALSE);
+
+	return mail;
+}
+
+static void
+smtp_client_transaction_connection_ready(struct smtp_client_transaction *trans)
+{
+	if (trans->state != SMTP_CLIENT_TRANSACTION_STATE_PENDING)
+		return;
+
+	e_debug(trans->event, "Connecton is ready for transaction");
+
+	trans->state = SMTP_CLIENT_TRANSACTION_STATE_MAIL_FROM;
+
+	smtp_client_transaction_submit_more(trans);
+}
+
+#undef smtp_client_transaction_start
+void smtp_client_transaction_start(
+	struct smtp_client_transaction *trans,
+	smtp_client_command_callback_t *mail_callback, void *context)
+{
+	struct smtp_client_connection *conn = trans->conn;
+	struct smtp_client_transaction_mail *mail = trans->mail_head;
+
+	i_assert(trans->state == SMTP_CLIENT_TRANSACTION_STATE_NEW);
+	i_assert(trans->conn != NULL);
+
+	i_assert(mail != NULL);
+	event_add_str(trans->event, "mail_from",
+		      smtp_address_encode(mail->mail_from));
+	event_add_str(trans->event, "mail_from_raw",
+		      smtp_address_encode_raw(mail->mail_from));
+	smtp_params_mail_add_to_event(&mail->mail_params,
+				      trans->event);
+
+	struct event_passthrough *e =
+		event_create_passthrough(trans->event)->
+		set_name("smtp_client_transaction_started");
+	e_debug(e->event(), "Start");
+
+	io_loop_time_refresh();
+	trans->times.started = ioloop_timeval;
+
+	i_assert(mail->mail_callback == NULL);
+
+	mail->mail_callback = mail_callback;
+	mail->context = context;
+
+	trans->state = SMTP_CLIENT_TRANSACTION_STATE_PENDING;
+
+	smtp_client_connection_add_transaction(conn, trans);
+
+	if (trans->immediate &&
+	    conn->state == SMTP_CLIENT_CONNECTION_STATE_READY) {
+		trans->state = SMTP_CLIENT_TRANSACTION_STATE_MAIL_FROM;
+
+		if (!trans->submitting)
+			smtp_client_transaction_submit_more(trans);
+	} else if (trans->cmd_last == NULL) {
+		trans->cmd_plug = trans->cmd_last =
+			smtp_client_command_plug(trans->conn, NULL);
+	}
+}
+
+#undef smtp_client_transaction_start_empty
+void smtp_client_transaction_start_empty(
+	struct smtp_client_transaction *trans,
+	const struct smtp_address *mail_from,
+	const struct smtp_params_mail *mail_params,
+	smtp_client_command_callback_t *mail_callback, void *context)
+{
+	i_assert(trans->mail_head == NULL);
+
+	(void)smtp_client_transaction_mail_new(trans, mail_from, mail_params);
+
+	smtp_client_transaction_start(trans, mail_callback, context);
+}
+
+static void
+smtp_client_transaction_rcpt_cb(const struct smtp_reply *reply,
+				struct smtp_client_transaction_rcpt *rcpt)
+{
+	struct smtp_client_transaction *trans = rcpt->trans;
+
+	i_assert(trans->conn != NULL);
+
+	e_debug(trans->event, "Got RCPT reply: %s", smtp_reply_log(reply));
+
+	/* Plug command line pipeline if DATA command is not yet issued */
+	if (!trans->immediate && !trans->reset &&
+	    rcpt->cmd_rcpt_to == trans->cmd_last && trans->cmd_data == NULL) {
+		trans->cmd_plug = trans->cmd_last =
+			smtp_client_command_plug(trans->conn, trans->cmd_last);
+	}
+	rcpt->cmd_rcpt_to = NULL;
+
+	{
+		enum smtp_client_transaction_state state;
+		struct smtp_client_transaction *tmp_trans = trans;
+
+		smtp_client_transaction_ref(tmp_trans);
+
+		smtp_client_transaction_rcpt_replied(&rcpt, reply);
+
+		state = trans->state;
+		smtp_client_transaction_unref(&tmp_trans);
+		if (state >= SMTP_CLIENT_TRANSACTION_STATE_FINISHED)
+			return;
+	}
+
+	smtp_client_transaction_try_complete(trans);
+}
+
+#undef smtp_client_transaction_add_rcpt
+struct smtp_client_transaction_rcpt *
+smtp_client_transaction_add_rcpt(struct smtp_client_transaction *trans,
+				 const struct smtp_address *rcpt_to,
+				 const struct smtp_params_rcpt *rcpt_params,
+				 smtp_client_command_callback_t *rcpt_callback,
+				 smtp_client_command_callback_t *data_callback,
+				 void *context)
+{
+	struct smtp_client_transaction_rcpt *rcpt;
+	pool_t pool;
+
+	e_debug(trans->event, "Add recipient");
+
+	i_assert(!trans->data_provided);
+	i_assert(!trans->reset);
+
+	i_assert(trans->state < SMTP_CLIENT_TRANSACTION_STATE_FINISHED);
+
+	if (trans->mail_head == NULL &&
+	    trans->state == SMTP_CLIENT_TRANSACTION_STATE_MAIL_FROM)
+		trans->state = SMTP_CLIENT_TRANSACTION_STATE_RCPT_TO;
+
+	pool = pool_alloconly_create("smtp transaction rcpt", 512);
+	rcpt = smtp_client_transaction_rcpt_new(trans, pool,
+						rcpt_to, rcpt_params);
+	pool_unref(&pool);
+
+	rcpt->rcpt_callback = rcpt_callback;
+	rcpt->context = context;
+
+	rcpt->data_callback = data_callback;
+	rcpt->data_context = context;
+
+	smtp_client_transaction_submit(trans, FALSE);
+
+	return rcpt;
+}
+
+#undef smtp_client_transaction_add_pool_rcpt
+struct smtp_client_transaction_rcpt *
+smtp_client_transaction_add_pool_rcpt(
+	struct smtp_client_transaction *trans, pool_t pool,
+	const struct smtp_address *rcpt_to,
+	const struct smtp_params_rcpt *rcpt_params,
+	smtp_client_command_callback_t *rcpt_callback, void *context)
+{
+	struct smtp_client_transaction_rcpt *rcpt;
+
+	e_debug(trans->event, "Add recipient (external pool)");
+
+	i_assert(!trans->data_provided);
+	i_assert(!trans->reset);
+
+	i_assert(trans->state < SMTP_CLIENT_TRANSACTION_STATE_FINISHED);
+
+	if (trans->mail_head == NULL &&
+	    trans->state == SMTP_CLIENT_TRANSACTION_STATE_MAIL_FROM)
+		trans->state = SMTP_CLIENT_TRANSACTION_STATE_RCPT_TO;
+
+	rcpt = smtp_client_transaction_rcpt_new(trans, pool,
+						rcpt_to, rcpt_params);
+	rcpt->rcpt_callback = rcpt_callback;
+	rcpt->context = context;
+	rcpt->external_pool = TRUE;
+
+	smtp_client_transaction_submit(trans, FALSE);
+
+	return rcpt;
+}
+
+static void
+smtp_client_transaction_data_cb(const struct smtp_reply *reply,
+				struct smtp_client_transaction *trans)
+{
+	bool reply_per_rcpt = HAS_ALL_BITS(
+		trans->flags, SMTP_CLIENT_TRANSACTION_FLAG_REPLY_PER_RCPT);
+
+	i_assert(!trans->reset);
+
+	smtp_client_transaction_ref(trans);
+
+	if (trans->data_input != NULL) {
+		event_add_int(trans->event, "data_sent",
+			      trans->data_input->v_offset);
+		i_stream_unref(&trans->data_input);
+	}
+
+	if (reply_per_rcpt &&
+	    trans->cmd_data != NULL && /* NULL when failed early */
+	    trans->rcpts_data == NULL && trans->rcpts_count > 0) {
+		smtp_client_command_set_replies(trans->cmd_data,
+						trans->rcpts_count);
+	}
+	while (trans->rcpts_data != NULL) {
+		struct smtp_client_transaction_rcpt *rcpt = trans->rcpts_data;
+
+		trans->rcpts_data = trans->rcpts_data->next;
+		smtp_client_transaction_rcpt_finished(rcpt, reply);
+		if (HAS_ALL_BITS(trans->flags,
+				 SMTP_CLIENT_TRANSACTION_FLAG_REPLY_PER_RCPT))
+			break;
+	}
+
+	if (reply_per_rcpt && trans->rcpts_count > 1 &&
+	    !smtp_reply_is_success(reply) && trans->data_failure == NULL)
+		trans->data_failure = smtp_reply_clone(trans->pool, reply);
+	if (trans->rcpts_data != NULL) {
+		smtp_client_transaction_unref(&trans);
+		return;
+	}
+
+	trans->cmd_data = NULL;
+
+	if (trans->data_callback != NULL)
+		trans->data_callback(reply, trans->data_context);
+	trans->data_callback = NULL;
+
+	/* finished */
+	smtp_client_transaction_finish(
+		trans, (trans->data_failure == NULL ?
+			reply : trans->data_failure));
+
+	smtp_client_transaction_unref(&trans);
+}
+
+static void
+smtp_client_transaction_send_data(struct smtp_client_transaction *trans)
+{
+	struct smtp_reply failure;
+
+	i_assert(!trans->reset);
+	i_assert(trans->data_input != NULL);
+
+	e_debug(trans->event, "Sending data");
+
+	timeout_remove(&trans->to_send);
+
+	i_zero(&failure);
+	if (trans->failure != NULL) {
+		smtp_client_transaction_fail_reply(trans, trans->failure);
+		failure = *trans->failure;
+		i_assert(failure.status != 0);
+	} else if ((trans->rcpts_count + trans->rcpts_queue_count) == 0) {
+		e_debug(trans->event, "No valid recipients");
+		if (trans->failure != NULL)
+			failure = *trans->failure;
+		else {
+			smtp_reply_init(&failure, 554, "No valid recipients");
+			failure.enhanced_code = SMTP_REPLY_ENH_CODE(5, 5, 0);
+		}
+		i_assert(failure.status != 0);
+	} else {
+		i_assert(trans->conn != NULL);
+
+		trans->cmd_data = smtp_client_command_data_submit_after(
+			trans->conn, 0, trans->cmd_last, trans->data_input,
+			smtp_client_transaction_data_cb, trans);
+		trans->submitted_data = TRUE;
+
+		if (trans->cmd_last != NULL)
+			smtp_client_command_unlock(trans->cmd_last);
+
+		smtp_client_transaction_try_complete(trans);
+	}
+
+	if (trans->cmd_plug != NULL)
+		smtp_client_command_abort(&trans->cmd_plug);
+	trans->cmd_last = NULL;
+
+	if (failure.status != 0)
+		smtp_client_transaction_finish(trans, &failure);
+}
+
+#undef smtp_client_transaction_send
+void smtp_client_transaction_send(
+	struct smtp_client_transaction *trans, struct istream *data_input,
+	smtp_client_command_callback_t *data_callback, void *data_context)
+{
+	i_assert(trans->state < SMTP_CLIENT_TRANSACTION_STATE_FINISHED);
+	i_assert(!trans->data_provided);
+	i_assert(!trans->reset);
+
+	if (trans->rcpts_queue_count == 0)
+		e_debug(trans->event, "Got all RCPT replies");
+
+	e_debug(trans->event, "Send");
+
+	trans->data_provided = TRUE;
+
+	i_assert(trans->data_input == NULL);
+	trans->data_input = i_stream_create_crlf(data_input);
+
+	trans->data_callback = data_callback;
+	trans->data_context = data_context;
+
+	if (trans->finish_timeout_msecs > 0) {
+		i_assert(trans->to_finish == NULL);
+		trans->to_finish = timeout_add(trans->finish_timeout_msecs,
+					       smtp_client_transaction_timeout,
+					       trans);
+	}
+
+	smtp_client_transaction_submit(trans, TRUE);
+}
+
+static void
+smtp_client_transaction_rset_cb(const struct smtp_reply *reply,
+				struct smtp_client_transaction *trans)
+{
+	smtp_client_transaction_ref(trans);
+
+	trans->cmd_rset = NULL;
+
+	if (trans->reset_callback != NULL)
+		trans->reset_callback(reply, trans->reset_context);
+	trans->reset_callback = NULL;
+
+	/* Finished */
+	smtp_client_transaction_finish(trans, reply);
+
+	smtp_client_transaction_unref(&trans);
+}
+
+static void
+smtp_client_transaction_send_reset(struct smtp_client_transaction *trans)
+{
+	struct smtp_reply failure;
+
+	i_assert(trans->reset);
+
+	e_debug(trans->event, "Sending reset");
+
+	timeout_remove(&trans->to_send);
+
+	i_zero(&failure);
+	if (trans->failure != NULL) {
+		smtp_client_transaction_fail_reply(trans, trans->failure);
+		failure = *trans->failure;
+		i_assert(failure.status != 0);
+	} else {
+		i_assert(trans->conn != NULL);
+
+		trans->cmd_rset = smtp_client_command_rset_submit_after(
+			trans->conn, 0, trans->cmd_last,
+			smtp_client_transaction_rset_cb, trans);
+
+		if (trans->cmd_last != NULL)
+			smtp_client_command_unlock(trans->cmd_last);
+
+		smtp_client_transaction_try_complete(trans);
+	}
+
+	if (trans->cmd_plug != NULL)
+		smtp_client_command_abort(&trans->cmd_plug);
+	trans->cmd_last = NULL;
+
+	if (failure.status != 0)
+		smtp_client_transaction_finish(trans, &failure);
+}
+
+#undef smtp_client_transaction_reset
+void smtp_client_transaction_reset(
+	struct smtp_client_transaction *trans,
+	smtp_client_command_callback_t *reset_callback, void *reset_context)
+{
+	i_assert(trans->state < SMTP_CLIENT_TRANSACTION_STATE_FINISHED);
+	i_assert(!trans->data_provided);
+	i_assert(!trans->reset);
+
+	e_debug(trans->event, "Reset");
+
+	trans->reset = TRUE;
+
+	trans->reset_callback = reset_callback;
+	trans->reset_context = reset_context;
+
+	if (trans->finish_timeout_msecs > 0) {
+		i_assert(trans->to_finish == NULL);
+		trans->to_finish = timeout_add(trans->finish_timeout_msecs,
+					       smtp_client_transaction_timeout,
+					       trans);
+	}
+
+	smtp_client_transaction_submit(trans, TRUE);
+}
+
+static void
+smtp_client_transaction_do_submit_more(struct smtp_client_transaction *trans)
+{
+	timeout_remove(&trans->to_send);
+
+	/* Check whether we already failed */
+	if (trans->failure == NULL &&
+	    trans->state > SMTP_CLIENT_TRANSACTION_STATE_MAIL_FROM)
+		trans->failure = trans->mail_failure;
+	if (trans->failure != NULL) {
+		smtp_client_transaction_fail_reply(trans, trans->failure);
+		return;
+	}
+
+	i_assert(trans->conn != NULL);
+
+	/* Make sure transaction is started */
+	if (trans->state == SMTP_CLIENT_TRANSACTION_STATE_NEW) {
+		enum smtp_client_transaction_state state;
+		struct smtp_client_transaction *tmp_trans = trans;
+
+		smtp_client_transaction_ref(tmp_trans);
+		smtp_client_transaction_start(tmp_trans, NULL, NULL);
+		state = trans->state;
+		smtp_client_transaction_unref(&tmp_trans);
+		if (state >= SMTP_CLIENT_TRANSACTION_STATE_FINISHED)
+			return;
+	}
+
+	if (trans->state <= SMTP_CLIENT_TRANSACTION_STATE_PENDING) {
+		if (trans->cmd_last == NULL) {
+			trans->cmd_plug = trans->cmd_last =
+				smtp_client_command_plug(trans->conn, NULL);
+		}
+		return;
+	}
+
+	/* MAIL */
+	if (trans->mail_send != NULL) {
+		e_debug(trans->event, "Sending MAIL command");
+
+		i_assert(trans->state ==
+			 SMTP_CLIENT_TRANSACTION_STATE_MAIL_FROM);
+
+		if (trans->cmd_last != NULL)
+			smtp_client_command_unlock(trans->cmd_last);
+
+		while (trans->mail_send != NULL) {
+			struct smtp_client_transaction_mail *mail =
+				trans->mail_send;
+
+			trans->mail_send = trans->mail_send->next;
+			mail->cmd_mail_from = trans->cmd_last =
+				smtp_client_command_mail_submit_after(
+					trans->conn, 0, trans->cmd_last,
+					mail->mail_from, &mail->mail_params,
+					smtp_client_transaction_mail_cb, trans);
+		}
+	} else if (trans->immediate)
+		trans->cmd_last = NULL;
+
+	/* RCPT */
+	if (trans->rcpts_send != NULL) {
+		e_debug(trans->event, "Sending recipients");
+
+		if (trans->cmd_last != NULL)
+			smtp_client_command_unlock(trans->cmd_last);
+
+		while (trans->rcpts_send != NULL) {
+			struct smtp_client_transaction_rcpt *rcpt =
+				trans->rcpts_send;
+
+			trans->rcpts_send = trans->rcpts_send->next;
+			rcpt->cmd_rcpt_to = trans->cmd_last =
+				smtp_client_command_rcpt_submit_after(
+					trans->conn, 0,	trans->cmd_last,
+					rcpt->rcpt_to, &rcpt->rcpt_params,
+					smtp_client_transaction_rcpt_cb, rcpt);
+		}
+	}
+
+	if (trans->cmd_plug != NULL &&
+	    (trans->immediate || trans->cmd_last != trans->cmd_plug))
+		smtp_client_command_abort(&trans->cmd_plug);
+	if (trans->cmd_last != NULL && !trans->immediate)
+		smtp_client_command_lock(trans->cmd_last);
+
+	/* DATA / RSET */
+	if (trans->reset) {
+		smtp_client_transaction_send_reset(trans);
+	} else if (trans->data_input != NULL) {
+		smtp_client_transaction_send_data(trans);
+	}
+}
+
+static void
+smtp_client_transaction_submit_more(struct smtp_client_transaction *trans)
+{
+	smtp_client_transaction_ref(trans);
+	trans->submitting = TRUE;
+	smtp_client_transaction_do_submit_more(trans);
+	trans->submitting = FALSE;
+	smtp_client_transaction_unref(&trans);
+}
+
+static void
+smtp_client_transaction_submit(struct smtp_client_transaction *trans,
+			       bool start)
+{
+	if (trans->failure == NULL && !start &&
+	    trans->state <= SMTP_CLIENT_TRANSACTION_STATE_PENDING) {
+		/* Cannot submit commands at this time */
+		return;
+	}
+
+	if (trans->immediate) {
+		/* Submit immediately if not failed already: avoid calling
+		   failure callbacks directly (which is the first thing
+		   smtp_client_transaction_submit_more() would do). */
+		if (trans->failure == NULL &&
+		    trans->state > SMTP_CLIENT_TRANSACTION_STATE_MAIL_FROM)
+			trans->failure = trans->mail_failure;
+		if (trans->failure == NULL) {
+			smtp_client_transaction_submit_more(trans);
+			return;
+		}
+	}
+
+	if (trans->to_send != NULL) {
+		/* Already scheduled command submission */
+		return;
+	}
+
+	trans->to_send = timeout_add_short(0,
+		smtp_client_transaction_submit_more, trans);
+}
+
+static void
+smtp_client_transaction_try_complete(struct smtp_client_transaction *trans)
+{
+	i_assert(trans->conn != NULL);
+
+	if (trans->rcpts_queue_count > 0) {
+		/* Not all RCPT replies have come in yet */
+		e_debug(trans->event,  "RCPT replies are still pending (%u/%u)",
+			trans->rcpts_queue_count,
+			(trans->rcpts_queue_count + trans->rcpts_count));
+		return;
+	}
+	if (!trans->data_provided && !trans->reset) {
+		/* Still waiting for application to issue either
+		   smtp_client_transaction_send() or
+		   smtp_client_transaction_reset() */
+		e_debug(trans->event, "Transaction is not yet complete");
+		return;
+	}
+
+	if (trans->state == SMTP_CLIENT_TRANSACTION_STATE_RCPT_TO) {
+		/* Completed at this instance */
+		e_debug(trans->event,
+			"Got all RCPT replies and transaction is complete");
+	}
+
+	if (trans->reset) {
+		/* Entering reset state */
+		trans->state = SMTP_CLIENT_TRANSACTION_STATE_RESET;
+
+		if (trans->cmd_rset == NULL)
+			return;
+	} else {
+		/* Entering data state */
+		trans->state = SMTP_CLIENT_TRANSACTION_STATE_DATA;
+
+		if (trans->rcpts_count == 0) {
+			/* abort transaction if all recipients failed */
+			smtp_client_transaction_abort(trans);
+			return;
+		}
+
+		if (trans->cmd_data == NULL)
+			return;
+
+		if (HAS_ALL_BITS(trans->flags,
+				 SMTP_CLIENT_TRANSACTION_FLAG_REPLY_PER_RCPT)) {
+			smtp_client_command_set_replies(trans->cmd_data,
+							trans->rcpts_count);
+		}
+	}
+
+	/* Got replies for all recipients and submitted our last command;
+	   the next transaction can submit its commands now. */
+	smtp_client_connection_next_transaction(trans->conn, trans);
+}
+
+void smtp_client_transaction_set_immediate(
+	struct smtp_client_transaction *trans, bool immediate)
+{
+	trans->immediate = immediate;
+}
+
+void smtp_client_transaction_connection_result(
+	struct smtp_client_transaction *trans,
+	const struct smtp_reply *reply)
+{
+	if (!smtp_reply_is_success(reply)) {
+		if (trans->state <= SMTP_CLIENT_TRANSACTION_STATE_PENDING) {
+			e_debug(trans->event, "Failed to connect: %s",
+				smtp_reply_log(reply));
+		} else {
+			e_debug(trans->event, "Connection lost: %s",
+				smtp_reply_log(reply));
+		}
+		smtp_client_transaction_fail_reply(trans, reply);
+		return;
+	}
+
+	smtp_client_transaction_connection_ready(trans);
+}
+
+void smtp_client_transaction_connection_destroyed(
+	struct smtp_client_transaction *trans)
+{
+	i_assert(trans->failure != NULL);
+	smtp_client_connection_unref(&trans->conn);
+}
+
+const struct smtp_client_transaction_times *
+smtp_client_transaction_get_times(struct smtp_client_transaction *trans)
+{
+	return &trans->times;
+}
+
+enum smtp_client_transaction_state
+smtp_client_transaction_get_state(struct smtp_client_transaction *trans)
+{
+	return trans->state;
+}
+
+const char *
+smtp_client_transaction_get_state_name(struct smtp_client_transaction *trans)
+{
+	i_assert(trans->state >= SMTP_CLIENT_TRANSACTION_STATE_NEW &&
+		 trans->state <= SMTP_CLIENT_TRANSACTION_STATE_ABORTED);
+	return smtp_client_transaction_state_names[trans->state];
+}
+
+const char *
+smtp_client_transaction_get_state_destription(
+	struct smtp_client_transaction *trans)
+{
+	enum smtp_client_connection_state conn_state;
+
+	switch (trans->state) {
+	case SMTP_CLIENT_TRANSACTION_STATE_NEW:
+		break;
+	case SMTP_CLIENT_TRANSACTION_STATE_PENDING:
+		i_assert(trans->conn != NULL);
+		conn_state = smtp_client_connection_get_state(trans->conn);
+		switch (conn_state) {
+		case SMTP_CLIENT_CONNECTION_STATE_CONNECTING:
+		case SMTP_CLIENT_CONNECTION_STATE_HANDSHAKING:
+		case SMTP_CLIENT_CONNECTION_STATE_AUTHENTICATING:
+			return smtp_client_connection_state_names[conn_state];
+		case SMTP_CLIENT_CONNECTION_STATE_TRANSACTION:
+			return "waiting for connection";
+		case SMTP_CLIENT_CONNECTION_STATE_DISCONNECTED:
+		case SMTP_CLIENT_CONNECTION_STATE_READY:
+		default:
+			break;
+		}
+		break;
+	case SMTP_CLIENT_TRANSACTION_STATE_MAIL_FROM:
+		return "waiting for reply to MAIL FROM";
+	case SMTP_CLIENT_TRANSACTION_STATE_RCPT_TO:
+		return "waiting for reply to RCPT TO";
+	case SMTP_CLIENT_TRANSACTION_STATE_DATA:
+		return "waiting for reply to DATA";
+	case SMTP_CLIENT_TRANSACTION_STATE_RESET:
+		return "waiting for reply to RESET";
+	case SMTP_CLIENT_TRANSACTION_STATE_FINISHED:
+		return "finished";
+	case SMTP_CLIENT_TRANSACTION_STATE_ABORTED:
+		return "aborted";
+	}
+	i_unreached();
+}
+
+void smtp_client_transaction_switch_ioloop(
+	struct smtp_client_transaction *trans)
+{
+	if (trans->to_send != NULL)
+		trans->to_send = io_loop_move_timeout(&trans->to_send);
+	if (trans->to_finish != NULL)
+		trans->to_finish = io_loop_move_timeout(&trans->to_finish);
+}