--- a/src/imap/ngx_imap.h
+++ b/src/imap/ngx_imap.h
@@ -7,22 +7,33 @@
 
 
 typedef struct {
-    ngx_chain_t  *send;
-} ngx_imap_request_t;
+    ngx_connection_t      *connection;
+
+    ngx_buf_t             *downstream_buffer;
+    ngx_buf_t             *upstream_buffer;
+} ngx_imap_proxy_ctx_t;
 
 
-#define NGX_POP3_USER    1
-#define NGX_POP3_PASS    2
-#define NGX_POP3_APOP    3
-#define NGX_POP3_STAT    4
-#define NGX_POP3_LIST    5
-#define NGX_POP3_RETR    6
-#define NGX_POP3_DELE    7
-#define NGX_POP3_NOOP    8
-#define NGX_POP3_RSET    9
-#define NGX_POP3_TOP     10
-#define NGX_POP3_UIDL    11
-#define NGX_POP3_QUIT    12
+typedef struct {
+    uint32_t               signature;         /* "IMAP" */
+
+    ngx_connection_t      *connection;
+    ngx_imap_proxy_ctx_t  *proxy;
+} ngx_imap_session_t;
+
+
+#define NGX_POP3_USER      1
+#define NGX_POP3_PASS      2
+#define NGX_POP3_APOP      3
+#define NGX_POP3_STAT      4
+#define NGX_POP3_LIST      5
+#define NGX_POP3_RETR      6
+#define NGX_POP3_DELE      7
+#define NGX_POP3_NOOP      8
+#define NGX_POP3_RSET      9
+#define NGX_POP3_TOP       10
+#define NGX_POP3_UIDL      11
+#define NGX_POP3_QUIT      12
 
 
 void ngx_imap_init_connection(ngx_connection_t *c);