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

Allows running the pending transaction until RSET, without abruptly aborting
it or issuing a DATA command.

diff --git a/src/lib-smtp/smtp-client-private.h b/src/lib-smtp/smtp-client-private.h
index 13f52ccb41181810483c8bdeb4caee97c1aa6280..2ab6e365ec9c4d87d2791db54ddf80be7999929e 100644 (file)
--- a/src/lib-smtp/smtp-client-private.h
+++ b/src/lib-smtp/smtp-client-private.h
@@ -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;
 
@@ -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;
 
@@ -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;

diff --git a/src/lib-smtp/smtp-client-transaction.c b/src/lib-smtp/smtp-client-transaction.c
index 9babcc9908d0cb71655147780ac44ba31ef1fffe..b0da38c315ef7aeea7e077cbcaa53f8773ac05e1 100644 (file)
--- a/src/lib-smtp/smtp-client-transaction.c
+++ b/src/lib-smtp/smtp-client-transaction.c
@@ -23,6 +23,7 @@ const char *const smtp_client_transaction_state_names[] = {
        "mail_from",
        "rcpt_to",
        "data",
+       "reset",
        "finished",
        "aborted"
 };
@@ -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
@@ -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);
@@ -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);
 
@@ -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);
@@ -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);
        }
 
@@ -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;
@@ -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);
@@ -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);
 
@@ -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);
@@ -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");
@@ -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");
@@ -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)
 {
@@ -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
@@ -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;
@@ -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;
@@ -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:

diff --git a/src/lib-smtp/smtp-client-transaction.h b/src/lib-smtp/smtp-client-transaction.h
index 2e2c17a0763685677696e89f817b8488bcf1a6a0..87fc98abb32c122acaa67464d28e62e7b978cf96 100644 (file)
--- a/src/lib-smtp/smtp-client-transaction.h
+++ b/src/lib-smtp/smtp-client-transaction.h
@@ -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
 };
@@ -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);