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lib-smtp: client: transaction: Add support for ending the transaction…
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… in a graceful RSET command.

Allows running the pending transaction until RSET, without abruptly aborting
it or issuing a DATA command.
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@stephanbosch @cmouse
stephanbosch authored and cmouse committed Oct 10, 2018
1 parent dee73f5 commit 7d8abb1
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Showing 3 changed files with 146 additions and 24 deletions.
6 changes: 5 additions & 1 deletion src/lib-smtp/smtp-client-private.h
View file
Expand Up @@ -78,7 +78,7 @@ struct smtp_client_transaction {
struct smtp_params_mail mail_params;

enum smtp_client_transaction_state state;
struct smtp_client_command *cmd_mail_from, *cmd_data;
struct smtp_client_command *cmd_mail_from, *cmd_data, *cmd_rset;
struct smtp_client_command *cmd_plug, *cmd_last;
struct smtp_reply *failure;

Expand All @@ -93,6 +93,9 @@ struct smtp_client_transaction {
smtp_client_command_callback_t *data_callback;
void *data_context;

smtp_client_command_callback_t *reset_callback;
void *reset_context;

smtp_client_transaction_callback_t *callback;
void *context;

Expand All @@ -102,6 +105,7 @@ struct smtp_client_transaction {
struct timeout *to_finish, *to_send;

bool data_provided:1;
bool reset:1;
bool finished:1;
bool failing:1;
bool submitted_data:1;
Expand Down
150 changes: 127 additions & 23 deletions src/lib-smtp/smtp-client-transaction.c
View file
Expand Up @@ -23,6 +23,7 @@ const char *const smtp_client_transaction_state_names[] = {
"mail_from",
"rcpt_to",
"data",
"reset",
"finished",
"aborted"
};
Expand All @@ -38,6 +39,8 @@ 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);

/*
* Recipient
Expand Down Expand Up @@ -252,10 +255,13 @@ void smtp_client_transaction_abort(struct smtp_client_transaction *trans)
if (conn->state != SMTP_CLIENT_CONNECTION_STATE_DISCONNECTED) {
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);
Expand Down Expand Up @@ -322,6 +328,8 @@ void smtp_client_transaction_destroy(struct smtp_client_transaction **_trans)
}
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);

Expand Down Expand Up @@ -394,15 +402,22 @@ void smtp_client_transaction_fail_reply(struct smtp_client_transaction *trans,
}
}

/* DATA */
if (!trans->data_provided) {
/* smtp_client_transaction_send() was not called yet
/* 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. */
rcpts = array_get_modifiable(&trans->rcpts, &count);
Expand All @@ -428,9 +443,10 @@ void smtp_client_transaction_fail_reply(struct smtp_client_transaction *trans,

trans->failing = FALSE;

if (trans->data_provided) {
if (trans->data_provided || trans->reset) {
/* abort the transaction only if smtp_client_transaction_send()
was called (and if it is not aborted already) */
or smtp_client_transaction_reset() was called (and if it is
not aborted already) */
smtp_client_transaction_abort(trans);
}

Expand Down Expand Up @@ -494,6 +510,8 @@ smtp_client_transaction_mail_cb(const struct smtp_reply *reply,

if (array_count(&trans->rcpts_pending) > 0)
trans->state = SMTP_CLIENT_TRANSACTION_STATE_RCPT_TO;
else if (trans->reset)
trans->state = SMTP_CLIENT_TRANSACTION_STATE_RESET;

if (trans->mail_from_callback != NULL) {
enum smtp_client_transaction_state state;
Expand Down Expand Up @@ -569,7 +587,7 @@ smtp_client_transaction_rcpt_cb(const struct smtp_reply *reply,
rcpt->rcpt_callback = NULL;

/* plug command line pipeline if DATA command is not yet issued */
if (rcpt->cmd_rcpt_to == trans->cmd_last &&
if (!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);
Expand Down Expand Up @@ -599,6 +617,7 @@ void smtp_client_transaction_add_rcpt(
smtp_client_transaction_debug(trans, "Add recipient");

i_assert(!trans->data_provided);
i_assert(!trans->reset);

i_assert(trans->state < SMTP_CLIENT_TRANSACTION_STATE_FINISHED);

Expand All @@ -622,6 +641,8 @@ smtp_client_transaction_data_cb(const struct smtp_reply *reply,
struct smtp_client_transaction_rcpt *const *rcpt;
unsigned int i, count;

i_assert(!trans->reset);

smtp_client_transaction_ref(trans);

rcpt = array_get_modifiable(&trans->rcpts, &count);
Expand Down Expand Up @@ -659,6 +680,7 @@ smtp_client_transaction_send_data(struct smtp_client_transaction *trans)
{
bool finished = FALSE;

i_assert(!trans->reset);
i_assert(trans->data_input != NULL);

smtp_client_transaction_debug(trans, "Sending data");
Expand Down Expand Up @@ -700,6 +722,8 @@ void smtp_client_transaction_send(
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 (array_count(&trans->rcpts_pending) == 0)
smtp_client_transaction_debug(trans, "Got all RCPT replies");
Expand All @@ -724,6 +748,72 @@ void smtp_client_transaction_send(
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);

smtp_client_transaction_unref(&trans);
}

static void
smtp_client_transaction_send_reset(struct smtp_client_transaction *trans)
{
i_assert(trans->reset);

smtp_client_transaction_debug(trans, "Sending reset");

timeout_remove(&trans->to_send);

trans->cmd_rset = smtp_client_command_rset_submit_after(
trans->conn, 0, trans->cmd_last,
smtp_client_transaction_rset_cb, trans);

i_assert(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;
}

#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);

smtp_client_transaction_debug(trans, "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_submit_more(struct smtp_client_transaction *trans)
{
Expand Down Expand Up @@ -779,9 +869,12 @@ smtp_client_transaction_submit_more(struct smtp_client_transaction *trans)
if (trans->cmd_plug != NULL && trans->cmd_last != trans->cmd_plug)
smtp_client_command_abort(&trans->cmd_plug);

/* DATA */
if (trans->data_input != NULL)
/* 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
Expand Down Expand Up @@ -816,9 +909,10 @@ smtp_client_transaction_try_complete(struct smtp_client_transaction *trans)
array_count(&trans->rcpts)));
return;
}
if (!trans->data_provided) {
/* Still waiting for application to issue
smtp_client_transaction_send() */
if (!trans->data_provided && !trans->reset) {
/* Still waiting for application to issue either
smtp_client_transaction_send() or
smtp_client_transaction_reset() */
smtp_client_transaction_debug(
trans, "Transaction is not yet complete");
return;
Expand All @@ -831,21 +925,29 @@ smtp_client_transaction_try_complete(struct smtp_client_transaction *trans)
"transaction is complete");
}

/* Entering DATA state */
trans->state = SMTP_CLIENT_TRANSACTION_STATE_DATA;
if (trans->reset) {
/* Entering reset state */
trans->state = SMTP_CLIENT_TRANSACTION_STATE_RESET;

if (array_count(&trans->rcpts) == 0) {
/* abort transaction if all recipients failed */
smtp_client_transaction_abort(trans);
return;
}
if (trans->cmd_rset == NULL)
return;
} else {
/* Entering data state */
trans->state = SMTP_CLIENT_TRANSACTION_STATE_DATA;

if (trans->cmd_data == NULL)
return;
if (array_count(&trans->rcpts) == 0) {
/* abort transaction if all recipients failed */
smtp_client_transaction_abort(trans);
return;
}

if (conn->protocol == SMTP_PROTOCOL_LMTP) {
smtp_client_command_set_replies(trans->cmd_data,
array_count(&trans->rcpts));
if (trans->cmd_data == NULL)
return;

if (conn->protocol == SMTP_PROTOCOL_LMTP) {
smtp_client_command_set_replies(trans->cmd_data,
array_count(&trans->rcpts));
}
}

/* Got replies for all recipients and submitted our last command;
Expand Down Expand Up @@ -922,6 +1024,8 @@ smtp_client_transaction_get_state_destription(
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:
Expand Down
14 changes: 14 additions & 0 deletions src/lib-smtp/smtp-client-transaction.h
View file
Expand Up @@ -13,6 +13,7 @@ enum smtp_client_transaction_state {
SMTP_CLIENT_TRANSACTION_STATE_MAIL_FROM,
SMTP_CLIENT_TRANSACTION_STATE_RCPT_TO,
SMTP_CLIENT_TRANSACTION_STATE_DATA,
SMTP_CLIENT_TRANSACTION_STATE_RESET,
SMTP_CLIENT_TRANSACTION_STATE_FINISHED,
SMTP_CLIENT_TRANSACTION_STATE_ABORTED
};
Expand Down Expand Up @@ -108,6 +109,19 @@ void smtp_client_transaction_send(
const struct smtp_reply *reply, typeof(data_context))), \
(smtp_client_command_callback_t *)data_callback, data_context)

/* Gracefully reset the transaction by sending the RSET command and waiting for
the response. This does not try to abort pending MAIL and RCPT commands,
allowing the transaction to be evaluated without proceeding with the DATA
command. */
void smtp_client_transaction_reset(
struct smtp_client_transaction *trans,
smtp_client_command_callback_t *reset_callback, void *reset_context);
#define smtp_client_transaction_reset(trans, reset_callback, reset_context) \
smtp_client_transaction_reset(trans, \
(smtp_client_command_callback_t *)reset_callback, \
reset_context + CALLBACK_TYPECHECK(reset_callback, void (*)( \
const struct smtp_reply *reply, typeof(reset_context))))

/* Return transaction statistics. */
const struct smtp_client_transaction_times *
smtp_client_transaction_get_times(struct smtp_client_transaction *trans);
Expand Down

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