new file mode 100644
--- /dev/null
+++ b/src/mail/ngx_mail_imap_module.c
@@ -0,0 +1,251 @@
+
+/*
+ * Copyright (C) Igor Sysoev
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_event.h>
+#include <ngx_mail.h>
+#include <ngx_mail_imap_module.h>
+
+
+static void *ngx_mail_imap_create_srv_conf(ngx_conf_t *cf);
+static char *ngx_mail_imap_merge_srv_conf(ngx_conf_t *cf, void *parent,
+    void *child);
+
+
+static ngx_str_t  ngx_mail_imap_default_capabilities[] = {
+    ngx_string("IMAP4"),
+    ngx_string("IMAP4rev1"),
+    ngx_string("UIDPLUS"),
+    ngx_null_string
+};
+
+
+static ngx_conf_bitmask_t  ngx_mail_imap_auth_methods[] = {
+    { ngx_string("plain"), NGX_MAIL_AUTH_PLAIN_ENABLED },
+    { ngx_string("login"), NGX_MAIL_AUTH_LOGIN_ENABLED },
+    { ngx_string("cram-md5"), NGX_MAIL_AUTH_CRAM_MD5_ENABLED },
+    { ngx_null_string, 0 }
+};
+
+
+static ngx_str_t  ngx_mail_imap_auth_methods_names[] = {
+    ngx_string("AUTH=PLAIN"),
+    ngx_string("AUTH=LOGIN"),
+    ngx_null_string,  /* APOP */
+    ngx_string("AUTH=CRAM-MD5")
+};
+
+
+static ngx_mail_protocol_t  ngx_mail_imap_protocol = {
+    ngx_string("imap"),
+    { 143, 993, 0, 0 },
+    NGX_MAIL_IMAP_PROTOCOL,
+
+    ngx_mail_imap_init_session,
+    ngx_mail_imap_init_protocol,
+    ngx_mail_imap_parse_command,
+    ngx_mail_imap_auth_state,
+
+    ngx_string("* BAD internal server error" CRLF)
+};
+
+
+static ngx_command_t  ngx_mail_imap_commands[] = {
+
+    { ngx_string("imap_client_buffer"),
+      NGX_MAIL_MAIN_CONF|NGX_MAIL_SRV_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_size_slot,
+      NGX_MAIL_SRV_CONF_OFFSET,
+      offsetof(ngx_mail_imap_srv_conf_t, client_buffer_size),
+      NULL },
+
+    { ngx_string("imap_capabilities"),
+      NGX_MAIL_MAIN_CONF|NGX_MAIL_SRV_CONF|NGX_CONF_1MORE,
+      ngx_mail_capabilities,
+      NGX_MAIL_SRV_CONF_OFFSET,
+      offsetof(ngx_mail_imap_srv_conf_t, capabilities),
+      NULL },
+
+    { ngx_string("imap_auth"),
+      NGX_MAIL_MAIN_CONF|NGX_MAIL_SRV_CONF|NGX_CONF_1MORE,
+      ngx_conf_set_bitmask_slot,
+      NGX_MAIL_SRV_CONF_OFFSET,
+      offsetof(ngx_mail_imap_srv_conf_t, auth_methods),
+      &ngx_mail_imap_auth_methods },
+
+      ngx_null_command
+};
+
+
+static ngx_mail_module_t  ngx_mail_imap_module_ctx = {
+    &ngx_mail_imap_protocol,               /* protocol */
+
+    NULL,                                  /* create main configuration */
+    NULL,                                  /* init main configuration */
+
+    ngx_mail_imap_create_srv_conf,         /* create server configuration */
+    ngx_mail_imap_merge_srv_conf           /* merge server configuration */
+};
+
+
+ngx_module_t  ngx_mail_imap_module = {
+    NGX_MODULE_V1,
+    &ngx_mail_imap_module_ctx,             /* module context */
+    ngx_mail_imap_commands,                /* module directives */
+    NGX_MAIL_MODULE,                       /* module type */
+    NULL,                                  /* init master */
+    NULL,                                  /* init module */
+    NULL,                                  /* init process */
+    NULL,                                  /* init thread */
+    NULL,                                  /* exit thread */
+    NULL,                                  /* exit process */
+    NULL,                                  /* exit master */
+    NGX_MODULE_V1_PADDING
+};
+
+
+static void *
+ngx_mail_imap_create_srv_conf(ngx_conf_t *cf)
+{
+    ngx_mail_imap_srv_conf_t  *iscf;
+
+    iscf = ngx_pcalloc(cf->pool, sizeof(ngx_mail_imap_srv_conf_t));
+    if (iscf == NULL) {
+        return NULL;
+    }
+
+    iscf->client_buffer_size = NGX_CONF_UNSET_SIZE;
+
+    if (ngx_array_init(&iscf->capabilities, cf->pool, 4, sizeof(ngx_str_t))
+        != NGX_OK)
+    {
+        return NULL;
+    }
+
+    return iscf;
+}
+
+
+static char *
+ngx_mail_imap_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child)
+{
+    ngx_mail_imap_srv_conf_t *prev = parent;
+    ngx_mail_imap_srv_conf_t *conf = child;
+
+    u_char      *p, *auth;
+    size_t       size;
+    ngx_str_t   *c, *d;
+    ngx_uint_t   i, m;
+
+    ngx_conf_merge_size_value(conf->client_buffer_size,
+                              prev->client_buffer_size,
+                              (size_t) ngx_pagesize);
+
+    ngx_conf_merge_bitmask_value(conf->auth_methods,
+                              prev->auth_methods,
+                              (NGX_CONF_BITMASK_SET
+                               |NGX_MAIL_AUTH_PLAIN_ENABLED));
+
+
+    if (conf->capabilities.nelts == 0) {
+        conf->capabilities = prev->capabilities;
+    }
+
+    if (conf->capabilities.nelts == 0) {
+
+        for (d = ngx_mail_imap_default_capabilities; d->len; d++) {
+            c = ngx_array_push(&conf->capabilities);
+            if (c == NULL) {
+                return NGX_CONF_ERROR;
+            }
+
+            *c = *d;
+        }
+    }
+
+    size = sizeof("* CAPABILITY" CRLF) - 1;
+
+    c = conf->capabilities.elts;
+    for (i = 0; i < conf->capabilities.nelts; i++) {
+        size += 1 + c[i].len;
+    }
+
+    for (m = NGX_MAIL_AUTH_PLAIN_ENABLED, i = 0;
+         m <= NGX_MAIL_AUTH_CRAM_MD5_ENABLED;
+         m <<= 1, i++)
+    {
+        if (m & conf->auth_methods) {
+            size += 1 + ngx_mail_imap_auth_methods_names[i].len;
+        }
+    }
+
+    p = ngx_palloc(cf->pool, size);
+    if (p == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    conf->capability.len = size;
+    conf->capability.data = p;
+
+    p = ngx_cpymem(p, "* CAPABILITY", sizeof("* CAPABILITY") - 1);
+
+    for (i = 0; i < conf->capabilities.nelts; i++) {
+        *p++ = ' ';
+        p = ngx_cpymem(p, c[i].data, c[i].len);
+    }
+
+    auth = p;
+
+    for (m = NGX_MAIL_AUTH_PLAIN_ENABLED, i = 0;
+         m <= NGX_MAIL_AUTH_CRAM_MD5_ENABLED;
+         m <<= 1, i++)
+    {
+        if (m & conf->auth_methods) {
+            *p++ = ' ';
+            p = ngx_cpymem(p, ngx_mail_imap_auth_methods_names[i].data,
+                           ngx_mail_imap_auth_methods_names[i].len);
+        }
+    }
+
+    *p++ = CR; *p = LF;
+
+
+    size += sizeof(" STARTTLS") - 1;
+
+    p = ngx_palloc(cf->pool, size);
+    if (p == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    conf->starttls_capability.len = size;
+    conf->starttls_capability.data = p;
+
+    p = ngx_cpymem(p, conf->capability.data,
+                   conf->capability.len - (sizeof(CRLF) - 1));
+    p = ngx_cpymem(p, " STARTTLS", sizeof(" STARTTLS") - 1);
+    *p++ = CR; *p = LF;
+
+
+    size = (auth - conf->capability.data) + sizeof(CRLF) - 1
+            + sizeof(" STARTTLS LOGINDISABLED") - 1;
+
+    p = ngx_palloc(cf->pool, size);
+    if (p == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    conf->starttls_only_capability.len = size;
+    conf->starttls_only_capability.data = p;
+
+    p = ngx_cpymem(p, conf->capability.data,
+                   auth - conf->capability.data);
+    p = ngx_cpymem(p, " STARTTLS LOGINDISABLED",
+                   sizeof(" STARTTLS LOGINDISABLED") - 1);
+    *p++ = CR; *p = LF;
+
+    return NGX_CONF_OK;
+}