submission: Add submission_backend_capabilities setting.

This can be used to specify which capabilities the (relay) backend supports,
avoiding the need to query the backend explicitly before the EHLO reply is sent
to the client.

diff --git a/src/submission/submission-backend-relay.c b/src/submission/submission-backend-relay.c
index ace0519801d580c705e40f8a83f6940260d26eab..43244d1b9839a609e28c71abccc5ac3a384b6949 100644 (file)
--- a/src/submission/submission-backend-relay.c
+++ b/src/submission/submission-backend-relay.c
@@ -166,6 +166,8 @@ int cmd_helo_relay(struct client *client, struct smtp_server_cmd_ctx *cmd,
        struct submission_backend_relay *backend = &client->backend;
        struct relay_cmd_helo_context *helo;
 
+       client_proxy_start(client);
+
        helo = p_new(cmd->pool, struct relay_cmd_helo_context, 1);
        helo->backend = backend;
        helo->cmd = cmd;
@@ -319,6 +321,8 @@ int cmd_mail_relay(struct client *client, struct smtp_server_cmd_ctx *cmd,
 
        relay_cmd_mail_update_xclient(backend);
 
+       client_proxy_start(client);
+
        /* queue command (pipeline) */
        mail_cmd = p_new(cmd->pool, struct relay_cmd_mail_context, 1);
        mail_cmd->backend = backend;
@@ -793,7 +797,6 @@ static void client_proxy_ready_cb(const struct smtp_reply *reply,
 {
        struct client *client = context;
        struct submission_backend_relay *backend = &client->backend;
-       enum smtp_capability caps;
 
        /* check relay status */
        if ((reply->status / 100) != 2) {
@@ -804,25 +807,23 @@ static void client_proxy_ready_cb(const struct smtp_reply *reply,
                return;
        }
 
-       /* propagate capabilities */
-       caps = smtp_client_connection_get_capabilities(backend->conn);
-       caps |= SMTP_CAPABILITY_AUTH | SMTP_CAPABILITY_PIPELINING |
-               SMTP_CAPABILITY_SIZE | SMTP_CAPABILITY_ENHANCEDSTATUSCODES |
-               SMTP_CAPABILITY_CHUNKING | SMTP_CAPABILITY_BURL |
-               SMTP_CAPABILITY_VRFY;
-       caps &= SUBMISSION_SUPPORTED_SMTP_CAPABILITIES;
-       smtp_server_connection_set_capabilities(client->conn, caps);
-
-       /* now that we know our capabilities, commence server protocol dialog */
-       smtp_server_connection_resume(client->conn);
+       /* notify the client about the fact that we're ready and propagate our
+          capabilities */
+       client_default_backend_started(client,
+               smtp_client_connection_get_capabilities(backend->conn));
 }
 
 void client_proxy_start(struct client *client)
 {
        struct submission_backend_relay *backend = &client->backend;
 
+       if (backend->started)
+               return;
+
        smtp_client_connection_connect(backend->conn,
                                       client_proxy_ready_cb, client);
+
+       backend->started = TRUE;
 }
 
 /* try to proxy pipelined commands in a similarly pipelined fashion */

diff --git a/src/submission/submission-backend-relay.h b/src/submission/submission-backend-relay.h
index 9aa6d0f8a6335af5fa7b4a68d97423168750c5e0..94fe6b9f107aaadc8cb0d33e62a092b9eabca7cd 100644 (file)
--- a/src/submission/submission-backend-relay.h
+++ b/src/submission/submission-backend-relay.h
@@ -28,6 +28,7 @@ struct submission_backend_relay {
        struct smtp_client_connection *conn;
 
        bool xclient_sent:1;
+       bool started:1;
 };
 
 void client_proxy_create(struct client *client,

diff --git a/src/submission/submission-client.c b/src/submission/submission-client.c
index f0d9c655dc19e75db2da4d197ed9e34e7dccc8a2..976c8180a483730d245f886c9d3e91fb97a56a6d 100644 (file)
--- a/src/submission/submission-client.c
+++ b/src/submission/submission-client.c
@@ -69,6 +69,58 @@ static const char *client_remote_id(struct client *client)
        return addr;
 }
 
+static void client_parse_backend_capabilities(struct client *client)
+{
+       const struct submission_settings *set = client->set;
+       const char *const *str;
+
+       client->backend_capabilities = SMTP_CAPABILITY_NONE;
+       if (set->submission_backend_capabilities == NULL)
+               return;
+
+       str = t_strsplit_spaces(set->submission_backend_capabilities, " ,");
+       for (; *str != NULL; str++) {
+               enum smtp_capability cap = smtp_capability_find_by_name(*str);
+
+               if (cap == SMTP_CAPABILITY_NONE) {
+                       i_warning("Unknown SMTP capability in submission_backend_capabilities: "
+                                 "%s", *str);
+                       continue;
+               }
+
+               client->backend_capabilities |= cap;
+       }
+
+       client->backend_capabilities_configured = TRUE;
+}
+
+void client_apply_backend_capabilities(struct client *client)
+{
+       enum smtp_capability caps = client->backend_capabilities;
+
+       /* propagate capabilities */
+       caps |= SMTP_CAPABILITY_AUTH | SMTP_CAPABILITY_PIPELINING |
+               SMTP_CAPABILITY_SIZE | SMTP_CAPABILITY_ENHANCEDSTATUSCODES |
+               SMTP_CAPABILITY_CHUNKING | SMTP_CAPABILITY_BURL |
+               SMTP_CAPABILITY_VRFY;
+       caps &= SUBMISSION_SUPPORTED_SMTP_CAPABILITIES;
+       smtp_server_connection_set_capabilities(client->conn, caps);
+}
+
+void client_default_backend_started(struct client *client,
+                                   enum smtp_capability caps)
+{
+       /* propagate capabilities from backend to frontend */
+       if (!client->backend_capabilities_configured) {
+               client->backend_capabilities = caps;
+               client_apply_backend_capabilities(client);
+
+               /* resume the server now that we have the backend
+                  capabilities */
+               smtp_server_connection_resume(client->conn);
+       }
+}
+
 static void client_init_urlauth(struct client *client)
 {
        static const char *access_apps[] = { "submit+", NULL };
@@ -132,17 +184,25 @@ struct client *client_create(int fd_in, int fd_out,
                        SMTP_SERVER_WORKAROUND_MAILBOX_FOR_PATH;
        }
 
+       client_parse_backend_capabilities(client);
+
        client->conn = smtp_server_connection_create(smtp_server,
                fd_in, fd_out, user->conn.remote_ip, user->conn.remote_port,
                FALSE, &smtp_set, &smtp_callbacks, client);
 
        client_proxy_create(client, set);
-       client_proxy_start(client);
 
        smtp_server_connection_login(client->conn,
                client->user->username, helo,
                pdata, pdata_len, user->conn.ssl_secured);
-       smtp_server_connection_start_pending(client->conn);
+
+       if (client->backend_capabilities_configured) {
+               client_apply_backend_capabilities(client);
+               smtp_server_connection_start(client->conn);
+       } else {
+               client_proxy_start(client);
+               smtp_server_connection_start_pending(client->conn);
+       }
 
        mail_set = mail_user_set_get_storage_set(user);
        if (*set->imap_urlauth_host != '\0' &&

diff --git a/src/submission/submission-client.h b/src/submission/submission-client.h
index 6c977fb6993cad3a40900f2ffd219f6361e11355..71d73b4d1754271062c83f970dfd4510babc908b 100644 (file)
--- a/src/submission/submission-client.h
+++ b/src/submission/submission-client.h
@@ -36,12 +36,14 @@ struct client {
 
        struct smtp_server_stats stats;
 
+       enum smtp_capability backend_capabilities;
        struct submission_backend_relay backend;
 
        bool standalone:1;
        bool disconnected:1;
        bool destroyed:1;
        bool anvil_sent:1;
+       bool backend_capabilities_configured:1;
 };
 
 extern struct client *submission_clients;
@@ -61,6 +63,10 @@ void client_disconnect(struct client *client, const char *prefix,
 
 typedef void (*client_input_callback_t)(struct client *context);
 
+void client_apply_backend_capabilities(struct client *client);
+void client_default_backend_started(struct client *client,
+                                   enum smtp_capability caps);
+
 const char *client_state_get_name(struct client *client);
 
 uoff_t client_get_max_mail_size(struct client *client);

diff --git a/src/submission/submission-commands.c b/src/submission/submission-commands.c
index 055a05c68eae7d9ae72272bb41194aebfa0e522f..fec5e02b79c8db437dc7adc7979f90603d3eacfa 100644 (file)
--- a/src/submission/submission-commands.c
+++ b/src/submission/submission-commands.c
@@ -11,8 +11,6 @@
 #include "imap-msgpart-url.h"
 #include "imap-urlauth.h"
 #include "imap-urlauth-fetch.h"
-#include "smtp-client.h"
-#include "smtp-client-connection.h"
 
 #include "submission-recipient.h"
 #include "submission-commands.h"
@@ -26,9 +24,7 @@ void submission_helo_reply_submit(struct smtp_server_cmd_ctx *cmd,
                                  struct smtp_server_cmd_helo *data)
 {
        struct client *client = smtp_server_connection_get_context(cmd->conn);
-       struct submission_backend_relay *backend = &client->backend;
-       enum smtp_capability proxy_caps =
-               smtp_client_connection_get_capabilities(backend->conn);
+       enum smtp_capability backend_caps = client->backend_capabilities;
        struct smtp_server_reply *reply;
        uoff_t cap_size;
 
@@ -51,16 +47,16 @@ void submission_helo_reply_submit(struct smtp_server_cmd_ctx *cmd,
                                    client->set->imap_urlauth_port);
                }
 
-               if ((proxy_caps & SMTP_CAPABILITY_8BITMIME) != 0)
+               if ((backend_caps & SMTP_CAPABILITY_8BITMIME) != 0)
                        smtp_server_reply_ehlo_add(reply, "8BITMIME");
                smtp_server_reply_ehlo_add(reply, "AUTH");
-               if ((proxy_caps & SMTP_CAPABILITY_BINARYMIME) != 0 &&
-                       (proxy_caps & SMTP_CAPABILITY_CHUNKING) != 0)
+               if ((backend_caps & SMTP_CAPABILITY_BINARYMIME) != 0 &&
+                   (backend_caps & SMTP_CAPABILITY_CHUNKING) != 0)
                        smtp_server_reply_ehlo_add(reply, "BINARYMIME");
                smtp_server_reply_ehlo_add_param(reply,
                        "BURL", "%s", str_c(burl_params));
                smtp_server_reply_ehlo_add(reply, "CHUNKING");
-               if ((proxy_caps & SMTP_CAPABILITY_DSN) != 0)
+               if ((backend_caps & SMTP_CAPABILITY_DSN) != 0)
                        smtp_server_reply_ehlo_add(reply, "DSN");
                smtp_server_reply_ehlo_add(reply,
                        "ENHANCEDSTATUSCODES");

diff --git a/src/submission/submission-settings.c b/src/submission/submission-settings.c
index ed962851fcefa756f8a27a81551da080859da604..99fdfb008200c51ab2b64f90bd1e6c0f7c4a9d95 100644 (file)
--- a/src/submission/submission-settings.c
+++ b/src/submission/submission-settings.c
@@ -70,6 +70,8 @@ static const struct setting_define submission_setting_defines[] = {
        DEF(SET_STR, submission_client_workarounds),
        DEF(SET_STR, submission_logout_format),
 
+       DEF(SET_STR, submission_backend_capabilities),
+
        DEF(SET_STR, submission_relay_host),
        DEF(SET_IN_PORT, submission_relay_port),
        DEF(SET_BOOL, submission_relay_trusted),
@@ -107,6 +109,8 @@ static const struct submission_settings submission_default_settings = {
        .submission_client_workarounds = "",
        .submission_logout_format = "in=%i out=%o",
 
+       .submission_backend_capabilities = NULL,
+
        .submission_relay_host = "",
        .submission_relay_port = 25,
        .submission_relay_trusted = FALSE,

diff --git a/src/submission/submission-settings.h b/src/submission/submission-settings.h
index c033c7dc8c1999bae6f0f34f9114d8e17bd688f7..691cd8970e1c35e1c2445963aaa543a352122fe1 100644 (file)
--- a/src/submission/submission-settings.h
+++ b/src/submission/submission-settings.h
@@ -25,6 +25,9 @@ struct submission_settings {
        const char *submission_client_workarounds;
        const char *submission_logout_format;
 
+       /* submission backend: */
+       const char *submission_backend_capabilities;
+
        /* submission relay: */
        const char *submission_relay_host;
        in_port_t submission_relay_port;