--- a/src/mail/ngx_mail.h
+++ b/src/mail/ngx_mail.h
@@ -68,6 +68,7 @@ typedef struct {
     ngx_array_t             listen;      /* ngx_mail_listen_t */
 } ngx_mail_core_main_conf_t;
 
+typedef void (*ngx_mail_handler_pt)(ngx_connection_t *c);
 
 #define NGX_MAIL_POP3_PROTOCOL  0
 #define NGX_MAIL_IMAP_PROTOCOL  1
@@ -104,6 +105,34 @@ typedef struct {
     ngx_array_t             imap_capabilities;
     ngx_array_t             smtp_capabilities;
 
+    /*
+     * Handlers:
+     *
+     *   - handler_init_session
+     *
+     *     Init new session after client connects. Protocol greetings printed
+     *     from here, so you need to define this if you need custom greeting
+     *     (or pause before greeting printed).
+     *
+     *   - handler_init_protocol
+     *
+     *     Initialize protocol-specific data after client sent first command.
+     *     Notably, this is re-called after STARTTLS negotiation.
+     *
+     *   - handler_read
+     *
+     *     Read client command. Could be the only handler used by simple
+     *     modules.
+     *
+     *     NB: handler_read is re-used after auth_http module work (if it was
+     *     called throgh ngx_mail_auth_http_init()) in case of error returned
+     *     by auth server, so you should set this if you use auth_http.
+     */
+
+    ngx_mail_handler_pt     handler_init_session;
+    ngx_event_handler_pt    handler_init_protocol;
+    ngx_event_handler_pt    handler_read;
+
     /* server ctx */
     ngx_mail_conf_ctx_t    *ctx;
 } ngx_mail_core_srv_conf_t;
@@ -247,6 +276,12 @@ typedef struct {
 #define NGX_SMTP_NOOP        5
 #define NGX_SMTP_MAIL        6
 #define NGX_SMTP_RSET        7
+#define NGX_SMTP_RCPT        8
+#define NGX_SMTP_DATA        9
+#define NGX_SMTP_VRFY        10
+#define NGX_SMTP_EXPN        11
+#define NGX_SMTP_HELP        12
+#define NGX_SMTP_STARTTLS    13
 
 
 #define NGX_MAIL_AUTH_PLAIN     0
@@ -285,6 +320,8 @@ typedef struct {
 
 #define ngx_mail_conf_get_module_main_conf(cf, module)                       \
     ((ngx_mail_conf_ctx_t *) cf->ctx)->main_conf[module.ctx_index]
+#define ngx_mail_conf_get_module_srv_conf(cf, module)                        \
+    ((ngx_mail_conf_ctx_t *) cf->ctx)->srv_conf[module.ctx_index]
 
 
 void ngx_mail_init_connection(ngx_connection_t *c);
@@ -295,10 +332,15 @@ void ngx_smtp_auth_state(ngx_event_t *re
 void ngx_mail_close_connection(ngx_connection_t *c);
 void ngx_mail_session_internal_server_error(ngx_mail_session_t *s);
 
+ngx_int_t ngx_mail_read_command(ngx_mail_session_t *s);
+
 ngx_int_t ngx_pop3_parse_command(ngx_mail_session_t *s);
 ngx_int_t ngx_imap_parse_command(ngx_mail_session_t *s);
 ngx_int_t ngx_smtp_parse_command(ngx_mail_session_t *s);
 
+#if (NGX_MAIL_SSL)
+void ngx_mail_starttls_handler(ngx_event_t *rev);
+#endif
 
 /* STUB */
 void ngx_mail_proxy_init(ngx_mail_session_t *s, ngx_peer_addr_t *peer);