Merged with the default branch.

11 files changed, 695 insertions, 35 deletions

diff --git a/src/mail/ngx_mail.c b/src/mail/ngx_mail.c
index f17c2ccc3..890d8153a 100644
--- a/src/mail/ngx_mail.c
+++ b/src/mail/ngx_mail.c
@@ -405,6 +405,7 @@ ngx_mail_add_addrs(ngx_conf_t *cf, ngx_mail_port_t *mport,
 #if (NGX_MAIL_SSL)
         addrs[i].conf.ssl = addr[i].opt.ssl;
 #endif
+        addrs[i].conf.proxy_protocol = addr[i].opt.proxy_protocol;
         addrs[i].conf.addr_text = addr[i].opt.addr_text;
     }
 
@@ -439,6 +440,7 @@ ngx_mail_add_addrs6(ngx_conf_t *cf, ngx_mail_port_t *mport,
 #if (NGX_MAIL_SSL)
         addrs6[i].conf.ssl = addr[i].opt.ssl;
 #endif
+        addrs6[i].conf.proxy_protocol = addr[i].opt.proxy_protocol;
         addrs6[i].conf.addr_text = addr[i].opt.addr_text;
     }
 
diff --git a/src/mail/ngx_mail.h b/src/mail/ngx_mail.h
index 25ac432b0..b865a3b9e 100644
--- a/src/mail/ngx_mail.h
+++ b/src/mail/ngx_mail.h
@@ -41,6 +41,7 @@ typedef struct {
     unsigned                ipv6only:1;
 #endif
     unsigned                so_keepalive:2;
+    unsigned                proxy_protocol:1;
 #if (NGX_HAVE_KEEPALIVE_TUNABLE)
     int                     tcp_keepidle;
     int                     tcp_keepintvl;
@@ -55,7 +56,8 @@ typedef struct {
 typedef struct {
     ngx_mail_conf_ctx_t    *ctx;
     ngx_str_t               addr_text;
-    ngx_uint_t              ssl;    /* unsigned   ssl:1; */
+    unsigned                ssl:1;
+    unsigned                proxy_protocol:1;
 } ngx_mail_addr_conf_t;
 
 typedef struct {
@@ -176,6 +178,7 @@ typedef enum {
 typedef struct {
     ngx_peer_connection_t   upstream;
     ngx_buf_t              *buffer;
+    ngx_uint_t              proxy_protocol;  /* unsigned  proxy_protocol:1; */
 } ngx_mail_proxy_ctx_t;
 
 
@@ -197,6 +200,7 @@ typedef struct {
 
     ngx_uint_t              mail_state;
 
+    unsigned                ssl:1;
     unsigned                protocol:3;
     unsigned                blocked:1;
     unsigned                quit:1;
@@ -405,6 +409,7 @@ char *ngx_mail_capabilities(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
 /* STUB */
 void ngx_mail_proxy_init(ngx_mail_session_t *s, ngx_addr_t *peer);
 void ngx_mail_auth_http_init(ngx_mail_session_t *s);
+ngx_int_t ngx_mail_realip_handler(ngx_mail_session_t *s);
 /**/
 
 
diff --git a/src/mail/ngx_mail_auth_http_module.c b/src/mail/ngx_mail_auth_http_module.c
index 6b57358b4..06ded470a 100644
--- a/src/mail/ngx_mail_auth_http_module.c
+++ b/src/mail/ngx_mail_auth_http_module.c
@@ -1224,22 +1224,49 @@ ngx_mail_auth_http_create_request(ngx_mail_session_t *s, ngx_pool_t *pool,
           + sizeof("Client-IP: ") - 1 + s->connection->addr_text.len
                 + sizeof(CRLF) - 1
           + sizeof("Client-Host: ") - 1 + s->host.len + sizeof(CRLF) - 1
-          + sizeof("Auth-SMTP-Helo: ") - 1 + s->smtp_helo.len + sizeof(CRLF) - 1
-          + sizeof("Auth-SMTP-From: ") - 1 + s->smtp_from.len + sizeof(CRLF) - 1
-          + sizeof("Auth-SMTP-To: ") - 1 + s->smtp_to.len + sizeof(CRLF) - 1
-#if (NGX_MAIL_SSL)
-          + sizeof("Auth-SSL: on" CRLF) - 1
-          + sizeof("Auth-SSL-Verify: ") - 1 + verify.len + sizeof(CRLF) - 1
-          + sizeof("Auth-SSL-Subject: ") - 1 + subject.len + sizeof(CRLF) - 1
-          + sizeof("Auth-SSL-Issuer: ") - 1 + issuer.len + sizeof(CRLF) - 1
-          + sizeof("Auth-SSL-Serial: ") - 1 + serial.len + sizeof(CRLF) - 1
-          + sizeof("Auth-SSL-Fingerprint: ") - 1 + fingerprint.len
-              + sizeof(CRLF) - 1
-          + sizeof("Auth-SSL-Cert: ") - 1 + cert.len + sizeof(CRLF) - 1
-#endif
           + ahcf->header.len
           + sizeof(CRLF) - 1;
 
+    if (c->proxy_protocol) {
+        len += sizeof("Proxy-Protocol-Addr: ") - 1
+                     + c->proxy_protocol->src_addr.len + sizeof(CRLF) - 1
+               + sizeof("Proxy-Protocol-Port: ") - 1
+                     + sizeof("65535") - 1 + sizeof(CRLF) - 1
+               + sizeof("Proxy-Protocol-Server-Addr: ") - 1
+                     + c->proxy_protocol->dst_addr.len + sizeof(CRLF) - 1
+               + sizeof("Proxy-Protocol-Server-Port: ") - 1
+                     + sizeof("65535") - 1 + sizeof(CRLF) - 1;
+    }
+
+    if (s->auth_method == NGX_MAIL_AUTH_NONE) {
+        len += sizeof("Auth-SMTP-Helo: ") - 1 + s->smtp_helo.len
+                     + sizeof(CRLF) - 1
+               + sizeof("Auth-SMTP-From: ") - 1 + s->smtp_from.len
+                     + sizeof(CRLF) - 1
+               + sizeof("Auth-SMTP-To: ") - 1 + s->smtp_to.len
+                     + sizeof(CRLF) - 1;
+    }
+
+#if (NGX_MAIL_SSL)
+
+    if (c->ssl) {
+        len += sizeof("Auth-SSL: on" CRLF) - 1
+               + sizeof("Auth-SSL-Verify: ") - 1 + verify.len
+                     + sizeof(CRLF) - 1
+               + sizeof("Auth-SSL-Subject: ") - 1 + subject.len
+                     + sizeof(CRLF) - 1
+               + sizeof("Auth-SSL-Issuer: ") - 1 + issuer.len
+                     + sizeof(CRLF) - 1
+               + sizeof("Auth-SSL-Serial: ") - 1 + serial.len
+                     + sizeof(CRLF) - 1
+               + sizeof("Auth-SSL-Fingerprint: ") - 1 + fingerprint.len
+                     + sizeof(CRLF) - 1
+               + sizeof("Auth-SSL-Cert: ") - 1 + cert.len
+                     + sizeof(CRLF) - 1;
+    }
+
+#endif
+
     b = ngx_create_temp_buf(pool, len);
     if (b == NULL) {
         return NULL;
@@ -1298,6 +1325,26 @@ ngx_mail_auth_http_create_request(ngx_mail_session_t *s, ngx_pool_t *pool,
         *b->last++ = CR; *b->last++ = LF;
     }
 
+    if (c->proxy_protocol) {
+        b->last = ngx_cpymem(b->last, "Proxy-Protocol-Addr: ",
+                             sizeof("Proxy-Protocol-Addr: ") - 1);
+        b->last = ngx_copy(b->last, c->proxy_protocol->src_addr.data,
+                           c->proxy_protocol->src_addr.len);
+        *b->last++ = CR; *b->last++ = LF;
+
+        b->last = ngx_sprintf(b->last, "Proxy-Protocol-Port: %d" CRLF,
+                              c->proxy_protocol->src_port);
+
+        b->last = ngx_cpymem(b->last, "Proxy-Protocol-Server-Addr: ",
+                             sizeof("Proxy-Protocol-Server-Addr: ") - 1);
+        b->last = ngx_copy(b->last, c->proxy_protocol->dst_addr.data,
+                           c->proxy_protocol->dst_addr.len);
+        *b->last++ = CR; *b->last++ = LF;
+
+        b->last = ngx_sprintf(b->last, "Proxy-Protocol-Server-Port: %d" CRLF,
+                              c->proxy_protocol->dst_port);
+    }
+
     if (s->auth_method == NGX_MAIL_AUTH_NONE) {
 
         /* HELO, MAIL FROM, and RCPT TO can't contain CRLF, no need to escape */
diff --git a/src/mail/ngx_mail_core_module.c b/src/mail/ngx_mail_core_module.c
index e16d70238..408312423 100644
--- a/src/mail/ngx_mail_core_module.c
+++ b/src/mail/ngx_mail_core_module.c
@@ -548,6 +548,11 @@ ngx_mail_core_listen(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
 #endif
         }
 
+        if (ngx_strcmp(value[i].data, "proxy_protocol") == 0) {
+            ls->proxy_protocol = 1;
+            continue;
+        }
+
         ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                            "the invalid \"%V\" parameter", &value[i]);
         return NGX_CONF_ERROR;
diff --git a/src/mail/ngx_mail_handler.c b/src/mail/ngx_mail_handler.c
index 803a247d2..b9010535b 100644
--- a/src/mail/ngx_mail_handler.c
+++ b/src/mail/ngx_mail_handler.c
@@ -11,6 +11,8 @@
 #include <ngx_mail.h>
 
 
+static void ngx_mail_proxy_protocol_handler(ngx_event_t *rev);
+static void ngx_mail_init_session_handler(ngx_event_t *rev);
 static void ngx_mail_init_session(ngx_connection_t *c);
 
 #if (NGX_MAIL_SSL)
@@ -26,6 +28,7 @@ ngx_mail_init_connection(ngx_connection_t *c)
 {
     size_t                     len;
     ngx_uint_t                 i;
+    ngx_event_t               *rev;
     ngx_mail_port_t           *port;
     struct sockaddr           *sa;
     struct sockaddr_in        *sin;
@@ -129,6 +132,10 @@ ngx_mail_init_connection(ngx_connection_t *c)
     s->main_conf = addr_conf->ctx->main_conf;
     s->srv_conf = addr_conf->ctx->srv_conf;
 
+#if (NGX_MAIL_SSL)
+    s->ssl = addr_conf->ssl;
+#endif
+
     s->addr_text = &addr_conf->addr_text;
 
     c->data = s;
@@ -159,13 +166,125 @@ ngx_mail_init_connection(ngx_connection_t *c)
 
     c->log_error = NGX_ERROR_INFO;
 
+    rev = c->read;
+    rev->handler = ngx_mail_init_session_handler;
+
+    if (addr_conf->proxy_protocol) {
+        c->log->action = "reading PROXY protocol";
+
+        rev->handler = ngx_mail_proxy_protocol_handler;
+
+        if (!rev->ready) {
+            ngx_add_timer(rev, cscf->timeout);
+
+            if (ngx_handle_read_event(rev, 0) != NGX_OK) {
+                ngx_mail_close_connection(c);
+            }
+
+            return;
+        }
+    }
+
+    if (ngx_use_accept_mutex) {
+        ngx_post_event(rev, &ngx_posted_events);
+        return;
+    }
+
+    rev->handler(rev);
+}
+
+
+static void
+ngx_mail_proxy_protocol_handler(ngx_event_t *rev)
+{
+    u_char                    *p, buf[NGX_PROXY_PROTOCOL_MAX_HEADER];
+    size_t                     size;
+    ssize_t                    n;
+    ngx_err_t                  err;
+    ngx_connection_t          *c;
+    ngx_mail_session_t        *s;
+    ngx_mail_core_srv_conf_t  *cscf;
+
+    c = rev->data;
+    s = c->data;
+
+    ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0,
+                   "mail PROXY protocol handler");
+
+    if (rev->timedout) {
+        ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out");
+        c->timedout = 1;
+        ngx_mail_close_connection(c);
+        return;
+    }
+
+    n = recv(c->fd, (char *) buf, sizeof(buf), MSG_PEEK);
+
+    err = ngx_socket_errno;
+
+    ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0, "recv(): %z", n);
+
+    if (n == -1) {
+        if (err == NGX_EAGAIN) {
+            rev->ready = 0;
+
+            if (!rev->timer_set) {
+                cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module);
+                ngx_add_timer(rev, cscf->timeout);
+            }
+
+            if (ngx_handle_read_event(rev, 0) != NGX_OK) {
+                ngx_mail_close_connection(c);
+            }
+
+            return;
+        }
+
+        ngx_connection_error(c, err, "recv() failed");
+
+        ngx_mail_close_connection(c);
+        return;
+    }
+
+    p = ngx_proxy_protocol_read(c, buf, buf + n);
+
+    if (p == NULL) {
+        ngx_mail_close_connection(c);
+        return;
+    }
+
+    size = p - buf;
+
+    if (c->recv(c, buf, size) != (ssize_t) size) {
+        ngx_mail_close_connection(c);
+        return;
+    }
+
+    if (ngx_mail_realip_handler(s) != NGX_OK) {
+        ngx_mail_close_connection(c);
+        return;
+    }
+
+    ngx_mail_init_session_handler(rev);
+}
+
+
+static void
+ngx_mail_init_session_handler(ngx_event_t *rev)
+{
+    ngx_connection_t    *c;
+    ngx_mail_session_t  *s;
+
+    c = rev->data;
+    s = c->data;
+
 #if (NGX_MAIL_SSL)
     {
     ngx_mail_ssl_conf_t  *sslcf;
 
     sslcf = ngx_mail_get_module_srv_conf(s, ngx_mail_ssl_module);
 
-    if (sslcf->enable || addr_conf->ssl) {
+    if (sslcf->enable || s->ssl) {
         c->log->action = "SSL handshaking";
 
         ngx_mail_ssl_init_connection(&sslcf->ssl, c);
@@ -215,9 +334,10 @@ ngx_mail_ssl_init_connection(ngx_ssl_t *ssl, ngx_connection_t *c)
 
         s = c->data;
 
-        cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module);
-
-        ngx_add_timer(c->read, cscf->timeout);
+        if (!c->read->timer_set) {
+            cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module);
+            ngx_add_timer(c->read, cscf->timeout);
+        }
 
         c->ssl->handler = ngx_mail_ssl_handshake_handler;
 
@@ -338,6 +458,8 @@ ngx_mail_init_session(ngx_connection_t *c)
 
     s = c->data;
 
+    c->log->action = "sending client greeting line";
+
     cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module);
 
     s->protocol = cscf->protocol->type;
@@ -722,11 +844,6 @@ ngx_mail_read_command(ngx_mail_session_t *s, ngx_connection_t *c)
     }
 
     if (n == NGX_AGAIN) {
-        if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
-            ngx_mail_session_internal_server_error(s);
-            return NGX_ERROR;
-        }
-
         if (s->buffer->pos == s->buffer->last) {
             return NGX_AGAIN;
         }
diff --git a/src/mail/ngx_mail_imap_handler.c b/src/mail/ngx_mail_imap_handler.c
index 3bf09ec3c..5dfdd7601 100644
--- a/src/mail/ngx_mail_imap_handler.c
+++ b/src/mail/ngx_mail_imap_handler.c
@@ -123,6 +123,12 @@ ngx_mail_imap_auth_state(ngx_event_t *rev)
     if (s->out.len) {
         ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "imap send handler busy");
         s->blocked = 1;
+
+        if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
+            ngx_mail_close_connection(c);
+            return;
+        }
+
         return;
     }
 
@@ -130,7 +136,16 @@ ngx_mail_imap_auth_state(ngx_event_t *rev)
 
     rc = ngx_mail_read_command(s, c);
 
-    if (rc == NGX_AGAIN || rc == NGX_ERROR) {
+    if (rc == NGX_AGAIN) {
+        if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
+            ngx_mail_session_internal_server_error(s);
+            return;
+        }
+
+        return;
+    }
+
+    if (rc == NGX_ERROR) {
         return;
     }
 
@@ -293,6 +308,11 @@ ngx_mail_imap_auth_state(ngx_event_t *rev)
         }
     }
 
+    if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
+        ngx_mail_session_internal_server_error(s);
+        return;
+    }
+
     ngx_mail_send(c->write);
 }
 
diff --git a/src/mail/ngx_mail_pop3_handler.c b/src/mail/ngx_mail_pop3_handler.c
index 9310c2750..edfd98681 100644
--- a/src/mail/ngx_mail_pop3_handler.c
+++ b/src/mail/ngx_mail_pop3_handler.c
@@ -138,6 +138,12 @@ ngx_mail_pop3_auth_state(ngx_event_t *rev)
     if (s->out.len) {
         ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "pop3 send handler busy");
         s->blocked = 1;
+
+        if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
+            ngx_mail_close_connection(c);
+            return;
+        }
+
         return;
     }
 
@@ -145,7 +151,16 @@ ngx_mail_pop3_auth_state(ngx_event_t *rev)
 
     rc = ngx_mail_read_command(s, c);
 
-    if (rc == NGX_AGAIN || rc == NGX_ERROR) {
+    if (rc == NGX_AGAIN) {
+        if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
+            ngx_mail_session_internal_server_error(s);
+            return;
+        }
+
+        return;
+    }
+
+    if (rc == NGX_ERROR) {
         return;
     }
 
@@ -275,6 +290,11 @@ ngx_mail_pop3_auth_state(ngx_event_t *rev)
             s->arg_start = s->buffer->start;
         }
 
+        if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
+            ngx_mail_session_internal_server_error(s);
+            return;
+        }
+
         ngx_mail_send(c->write);
     }
 }
diff --git a/src/mail/ngx_mail_proxy_module.c b/src/mail/ngx_mail_proxy_module.c
index 610f54780..66aa0ba09 100644
--- a/src/mail/ngx_mail_proxy_module.c
+++ b/src/mail/ngx_mail_proxy_module.c
@@ -17,6 +17,7 @@ typedef struct {
     ngx_flag_t  pass_error_message;
     ngx_flag_t  xclient;
     ngx_flag_t  smtp_auth;
+    ngx_flag_t  proxy_protocol;
     size_t      buffer_size;
     ngx_msec_t  timeout;
 } ngx_mail_proxy_conf_t;
@@ -26,7 +27,8 @@ static void ngx_mail_proxy_block_read(ngx_event_t *rev);
 static void ngx_mail_proxy_pop3_handler(ngx_event_t *rev);
 static void ngx_mail_proxy_imap_handler(ngx_event_t *rev);
 static void ngx_mail_proxy_smtp_handler(ngx_event_t *rev);
-static void ngx_mail_proxy_dummy_handler(ngx_event_t *ev);
+static void ngx_mail_proxy_write_handler(ngx_event_t *wev);
+static ngx_int_t ngx_mail_proxy_send_proxy_protocol(ngx_mail_session_t *s);
 static ngx_int_t ngx_mail_proxy_read_response(ngx_mail_session_t *s,
     ngx_uint_t state);
 static void ngx_mail_proxy_handler(ngx_event_t *ev);
@@ -82,6 +84,13 @@ static ngx_command_t  ngx_mail_proxy_commands[] = {
       offsetof(ngx_mail_proxy_conf_t, smtp_auth),
       NULL },
 
+    { ngx_string("proxy_protocol"),
+      NGX_MAIL_MAIN_CONF|NGX_MAIL_SRV_CONF|NGX_CONF_FLAG,
+      ngx_conf_set_flag_slot,
+      NGX_MAIL_SRV_CONF_OFFSET,
+      offsetof(ngx_mail_proxy_conf_t, proxy_protocol),
+      NULL },
+
       ngx_null_command
 };
 
@@ -156,7 +165,7 @@ ngx_mail_proxy_init(ngx_mail_session_t *s, ngx_addr_t *peer)
     p->upstream.connection->pool = s->connection->pool;
 
     s->connection->read->handler = ngx_mail_proxy_block_read;
-    p->upstream.connection->write->handler = ngx_mail_proxy_dummy_handler;
+    p->upstream.connection->write->handler = ngx_mail_proxy_write_handler;
 
     pcf = ngx_mail_get_module_srv_conf(s, ngx_mail_proxy_module);
 
@@ -167,6 +176,8 @@ ngx_mail_proxy_init(ngx_mail_session_t *s, ngx_addr_t *peer)
         return;
     }
 
+    s->proxy->proxy_protocol = pcf->proxy_protocol;
+
     s->out.len = 0;
 
     switch (s->protocol) {
@@ -186,6 +197,12 @@ ngx_mail_proxy_init(ngx_mail_session_t *s, ngx_addr_t *peer)
         s->mail_state = ngx_smtp_start;
         break;
     }
+
+    if (rc == NGX_AGAIN) {
+        return;
+    }
+
+    ngx_mail_proxy_write_handler(p->upstream.connection->write);
 }
 
 
@@ -230,9 +247,25 @@ ngx_mail_proxy_pop3_handler(ngx_event_t *rev)
         return;
     }
 
+    if (s->proxy->proxy_protocol) {
+        ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "mail proxy pop3 busy");
+
+        if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
+            ngx_mail_proxy_internal_server_error(s);
+            return;
+        }
+
+        return;
+    }
+
     rc = ngx_mail_proxy_read_response(s, 0);
 
     if (rc == NGX_AGAIN) {
+        if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
+            ngx_mail_proxy_internal_server_error(s);
+            return;
+        }
+
         return;
     }
 
@@ -314,6 +347,11 @@ ngx_mail_proxy_pop3_handler(ngx_event_t *rev)
         return;
     }
 
+    if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
+        ngx_mail_proxy_internal_server_error(s);
+        return;
+    }
+
     s->proxy->buffer->pos = s->proxy->buffer->start;
     s->proxy->buffer->last = s->proxy->buffer->start;
 }
@@ -343,9 +381,25 @@ ngx_mail_proxy_imap_handler(ngx_event_t *rev)
         return;
     }
 
+    if (s->proxy->proxy_protocol) {
+        ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "mail proxy imap busy");
+
+        if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
+            ngx_mail_proxy_internal_server_error(s);
+            return;
+        }
+
+        return;
+    }
+
     rc = ngx_mail_proxy_read_response(s, s->mail_state);
 
     if (rc == NGX_AGAIN) {
+        if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
+            ngx_mail_proxy_internal_server_error(s);
+            return;
+        }
+
         return;
     }
 
@@ -448,6 +502,11 @@ ngx_mail_proxy_imap_handler(ngx_event_t *rev)
         return;
     }
 
+    if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
+        ngx_mail_proxy_internal_server_error(s);
+        return;
+    }
+
     s->proxy->buffer->pos = s->proxy->buffer->start;
     s->proxy->buffer->last = s->proxy->buffer->start;
 }
@@ -479,9 +538,25 @@ ngx_mail_proxy_smtp_handler(ngx_event_t *rev)
         return;
     }
 
+    if (s->proxy->proxy_protocol) {
+        ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "mail proxy smtp busy");
+
+        if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
+            ngx_mail_proxy_internal_server_error(s);
+            return;
+        }
+
+        return;
+    }
+
     rc = ngx_mail_proxy_read_response(s, s->mail_state);
 
     if (rc == NGX_AGAIN) {
+        if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
+            ngx_mail_proxy_internal_server_error(s);
+            return;
+        }
+
         return;
     }
 
@@ -763,25 +838,103 @@ ngx_mail_proxy_smtp_handler(ngx_event_t *rev)
         return;
     }
 
+    if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
+        ngx_mail_proxy_internal_server_error(s);
+        return;
+    }
+
     s->proxy->buffer->pos = s->proxy->buffer->start;
     s->proxy->buffer->last = s->proxy->buffer->start;
 }
 
 
 static void
-ngx_mail_proxy_dummy_handler(ngx_event_t *wev)
+ngx_mail_proxy_write_handler(ngx_event_t *wev)
 {
     ngx_connection_t    *c;
     ngx_mail_session_t  *s;
 
-    ngx_log_debug0(NGX_LOG_DEBUG_MAIL, wev->log, 0, "mail proxy dummy handler");
+    ngx_log_debug0(NGX_LOG_DEBUG_MAIL, wev->log, 0, "mail proxy write handler");
+
+    c = wev->data;
+    s = c->data;
+
+    if (s->proxy->proxy_protocol) {
+        if (ngx_mail_proxy_send_proxy_protocol(s) != NGX_OK) {
+            return;
+        }
+
+        s->proxy->proxy_protocol = 0;
+    }
 
     if (ngx_handle_write_event(wev, 0) != NGX_OK) {
-        c = wev->data;
-        s = c->data;
+        ngx_mail_proxy_internal_server_error(s);
+    }
 
-        ngx_mail_proxy_close_session(s);
+    if (c->read->ready) {
+        ngx_post_event(c->read, &ngx_posted_events);
+    }
+}
+
+
+static ngx_int_t
+ngx_mail_proxy_send_proxy_protocol(ngx_mail_session_t *s)
+{
+    u_char            *p;
+    ssize_t            n, size;
+    ngx_connection_t  *c;
+    u_char             buf[NGX_PROXY_PROTOCOL_MAX_HEADER];
+
+    s->connection->log->action = "sending PROXY protocol header to upstream";
+
+    ngx_log_debug0(NGX_LOG_DEBUG_MAIL, s->connection->log, 0,
+                   "mail proxy send PROXY protocol header");
+
+    p = ngx_proxy_protocol_write(s->connection, buf,
+                                 buf + NGX_PROXY_PROTOCOL_MAX_HEADER);
+    if (p == NULL) {
+        ngx_mail_proxy_internal_server_error(s);
+        return NGX_ERROR;
     }
+
+    c = s->proxy->upstream.connection;
+
+    size = p - buf;
+
+    n = c->send(c, buf, size);
+
+    if (n == NGX_AGAIN) {
+        if (ngx_handle_write_event(c->write, 0) != NGX_OK) {
+            ngx_mail_proxy_internal_server_error(s);
+            return NGX_ERROR;
+        }
+
+        return NGX_AGAIN;
+    }
+
+    if (n == NGX_ERROR) {
+        ngx_mail_proxy_internal_server_error(s);
+        return NGX_ERROR;
+    }
+
+    if (n != size) {
+
+        /*
+         * PROXY protocol specification:
+         * The sender must always ensure that the header
+         * is sent at once, so that the transport layer
+         * maintains atomicity along the path to the receiver.
+         */
+
+        ngx_log_error(NGX_LOG_ERR, s->connection->log, 0,
+                      "could not send PROXY protocol header at once");
+
+        ngx_mail_proxy_internal_server_error(s);
+
+        return NGX_ERROR;
+    }
+
+    return NGX_OK;
 }
 
 
@@ -1182,6 +1335,7 @@ ngx_mail_proxy_create_conf(ngx_conf_t *cf)
     pcf->pass_error_message = NGX_CONF_UNSET;
     pcf->xclient = NGX_CONF_UNSET;
     pcf->smtp_auth = NGX_CONF_UNSET;
+    pcf->proxy_protocol = NGX_CONF_UNSET;
     pcf->buffer_size = NGX_CONF_UNSET_SIZE;
     pcf->timeout = NGX_CONF_UNSET_MSEC;
 
@@ -1199,6 +1353,7 @@ ngx_mail_proxy_merge_conf(ngx_conf_t *cf, void *parent, void *child)
     ngx_conf_merge_value(conf->pass_error_message, prev->pass_error_message, 0);
     ngx_conf_merge_value(conf->xclient, prev->xclient, 1);
     ngx_conf_merge_value(conf->smtp_auth, prev->smtp_auth, 0);
+    ngx_conf_merge_value(conf->proxy_protocol, prev->proxy_protocol, 0);
     ngx_conf_merge_size_value(conf->buffer_size, prev->buffer_size,
                               (size_t) ngx_pagesize);
     ngx_conf_merge_msec_value(conf->timeout, prev->timeout, 24 * 60 * 60000);
diff --git a/src/mail/ngx_mail_realip_module.c b/src/mail/ngx_mail_realip_module.c
new file mode 100644
index 000000000..c93d7d33c
--- /dev/null
+++ b/src/mail/ngx_mail_realip_module.c
@@ -0,0 +1,269 @@
+
+/*
+ * Copyright (C) Igor Sysoev
+ * Copyright (C) Nginx, Inc.
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_mail.h>
+
+
+typedef struct {
+    ngx_array_t       *from;     /* array of ngx_cidr_t */
+} ngx_mail_realip_srv_conf_t;
+
+
+static ngx_int_t ngx_mail_realip_set_addr(ngx_mail_session_t *s,
+    ngx_addr_t *addr);
+static char *ngx_mail_realip_from(ngx_conf_t *cf, ngx_command_t *cmd,
+    void *conf);
+static void *ngx_mail_realip_create_srv_conf(ngx_conf_t *cf);
+static char *ngx_mail_realip_merge_srv_conf(ngx_conf_t *cf, void *parent,
+    void *child);
+
+
+static ngx_command_t  ngx_mail_realip_commands[] = {
+
+    { ngx_string("set_real_ip_from"),
+      NGX_MAIL_MAIN_CONF|NGX_MAIL_SRV_CONF|NGX_CONF_TAKE1,
+      ngx_mail_realip_from,
+      NGX_MAIL_SRV_CONF_OFFSET,
+      0,
+      NULL },
+
+      ngx_null_command
+};
+
+
+static ngx_mail_module_t  ngx_mail_realip_module_ctx = {
+    NULL,                                  /* protocol */
+
+    NULL,                                  /* create main configuration */
+    NULL,                                  /* init main configuration */
+
+    ngx_mail_realip_create_srv_conf,       /* create server configuration */
+    ngx_mail_realip_merge_srv_conf         /* merge server configuration */
+};
+
+
+ngx_module_t  ngx_mail_realip_module = {
+    NGX_MODULE_V1,
+    &ngx_mail_realip_module_ctx,           /* module context */
+    ngx_mail_realip_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
+};
+
+
+ngx_int_t
+ngx_mail_realip_handler(ngx_mail_session_t *s)
+{
+    ngx_addr_t                   addr;
+    ngx_connection_t            *c;
+    ngx_mail_realip_srv_conf_t  *rscf;
+
+    rscf = ngx_mail_get_module_srv_conf(s, ngx_mail_realip_module);
+
+    if (rscf->from == NULL) {
+        return NGX_OK;
+    }
+
+    c = s->connection;
+
+    if (c->proxy_protocol == NULL) {
+        return NGX_OK;
+    }
+
+    if (ngx_cidr_match(c->sockaddr, rscf->from) != NGX_OK) {
+        return NGX_OK;
+    }
+
+    if (ngx_parse_addr(c->pool, &addr, c->proxy_protocol->src_addr.data,
+                       c->proxy_protocol->src_addr.len)
+        != NGX_OK)
+    {
+        return NGX_OK;
+    }
+
+    ngx_inet_set_port(addr.sockaddr, c->proxy_protocol->src_port);
+
+    return ngx_mail_realip_set_addr(s, &addr);
+}
+
+
+static ngx_int_t
+ngx_mail_realip_set_addr(ngx_mail_session_t *s, ngx_addr_t *addr)
+{
+    size_t             len;
+    u_char            *p;
+    u_char             text[NGX_SOCKADDR_STRLEN];
+    ngx_connection_t  *c;
+
+    c = s->connection;
+
+    len = ngx_sock_ntop(addr->sockaddr, addr->socklen, text,
+                        NGX_SOCKADDR_STRLEN, 0);
+    if (len == 0) {
+        return NGX_ERROR;
+    }
+
+    p = ngx_pnalloc(c->pool, len);
+    if (p == NULL) {
+        return NGX_ERROR;
+    }
+
+    ngx_memcpy(p, text, len);
+
+    c->sockaddr = addr->sockaddr;
+    c->socklen = addr->socklen;
+    c->addr_text.len = len;
+    c->addr_text.data = p;
+
+    return NGX_OK;
+}
+
+
+static char *
+ngx_mail_realip_from(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
+{
+    ngx_mail_realip_srv_conf_t *rscf = conf;
+
+    ngx_int_t             rc;
+    ngx_str_t            *value;
+    ngx_url_t             u;
+    ngx_cidr_t            c, *cidr;
+    ngx_uint_t            i;
+    struct sockaddr_in   *sin;
+#if (NGX_HAVE_INET6)
+    struct sockaddr_in6  *sin6;
+#endif
+
+    value = cf->args->elts;
+
+    if (rscf->from == NULL) {
+        rscf->from = ngx_array_create(cf->pool, 2,
+                                      sizeof(ngx_cidr_t));
+        if (rscf->from == NULL) {
+            return NGX_CONF_ERROR;
+        }
+    }
+
+#if (NGX_HAVE_UNIX_DOMAIN)
+
+    if (ngx_strcmp(value[1].data, "unix:") == 0) {
+        cidr = ngx_array_push(rscf->from);
+        if (cidr == NULL) {
+            return NGX_CONF_ERROR;
+        }
+
+        cidr->family = AF_UNIX;
+        return NGX_CONF_OK;
+    }
+
+#endif
+
+    rc = ngx_ptocidr(&value[1], &c);
+
+    if (rc != NGX_ERROR) {
+        if (rc == NGX_DONE) {
+            ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
+                               "low address bits of %V are meaningless",
+                               &value[1]);
+        }
+
+        cidr = ngx_array_push(rscf->from);
+        if (cidr == NULL) {
+            return NGX_CONF_ERROR;
+        }
+
+        *cidr = c;
+
+        return NGX_CONF_OK;
+    }
+
+    ngx_memzero(&u, sizeof(ngx_url_t));
+    u.host = value[1];
+
+    if (ngx_inet_resolve_host(cf->pool, &u) != NGX_OK) {
+        if (u.err) {
+            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                               "%s in set_real_ip_from \"%V\"",
+                               u.err, &u.host);
+        }
+
+        return NGX_CONF_ERROR;
+    }
+
+    cidr = ngx_array_push_n(rscf->from, u.naddrs);
+    if (cidr == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    ngx_memzero(cidr, u.naddrs * sizeof(ngx_cidr_t));
+
+    for (i = 0; i < u.naddrs; i++) {
+        cidr[i].family = u.addrs[i].sockaddr->sa_family;
+
+        switch (cidr[i].family) {
+
+#if (NGX_HAVE_INET6)
+        case AF_INET6:
+            sin6 = (struct sockaddr_in6 *) u.addrs[i].sockaddr;
+            cidr[i].u.in6.addr = sin6->sin6_addr;
+            ngx_memset(cidr[i].u.in6.mask.s6_addr, 0xff, 16);
+            break;
+#endif
+
+        default: /* AF_INET */
+            sin = (struct sockaddr_in *) u.addrs[i].sockaddr;
+            cidr[i].u.in.addr = sin->sin_addr.s_addr;
+            cidr[i].u.in.mask = 0xffffffff;
+            break;
+        }
+    }
+
+    return NGX_CONF_OK;
+}
+
+
+static void *
+ngx_mail_realip_create_srv_conf(ngx_conf_t *cf)
+{
+    ngx_mail_realip_srv_conf_t  *conf;
+
+    conf = ngx_pcalloc(cf->pool, sizeof(ngx_mail_realip_srv_conf_t));
+    if (conf == NULL) {
+        return NULL;
+    }
+
+    /*
+     * set by ngx_pcalloc():
+     *
+     *     conf->from = NULL;
+     */
+
+    return conf;
+}
+
+
+static char *
+ngx_mail_realip_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child)
+{
+    ngx_mail_realip_srv_conf_t *prev = parent;
+    ngx_mail_realip_srv_conf_t *conf = child;
+
+    if (conf->from == NULL) {
+        conf->from = prev->from;
+    }
+
+    return NGX_CONF_OK;
+}
diff --git a/src/mail/ngx_mail_smtp_handler.c b/src/mail/ngx_mail_smtp_handler.c
index f1017e0d8..e68ceedfd 100644
--- a/src/mail/ngx_mail_smtp_handler.c
+++ b/src/mail/ngx_mail_smtp_handler.c
@@ -449,6 +449,12 @@ ngx_mail_smtp_auth_state(ngx_event_t *rev)
     if (s->out.len) {
         ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "smtp send handler busy");
         s->blocked = 1;
+
+        if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
+            ngx_mail_close_connection(c);
+            return;
+        }
+
         return;
     }
 
@@ -456,7 +462,16 @@ ngx_mail_smtp_auth_state(ngx_event_t *rev)
 
     rc = ngx_mail_read_command(s, c);
 
-    if (rc == NGX_AGAIN || rc == NGX_ERROR) {
+    if (rc == NGX_AGAIN) {
+        if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
+            ngx_mail_session_internal_server_error(s);
+            return;
+        }
+
+        return;
+    }
+
+    if (rc == NGX_ERROR) {
         return;
     }
 
@@ -568,6 +583,11 @@ ngx_mail_smtp_auth_state(ngx_event_t *rev)
             s->arg_start = s->buffer->pos;
         }
 
+        if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
+            ngx_mail_session_internal_server_error(s);
+            return;
+        }
+
         ngx_mail_send(c->write);
     }
 }
diff --git a/src/mail/ngx_mail_ssl_module.c b/src/mail/ngx_mail_ssl_module.c
index d560bd60c..7eae83e25 100644
--- a/src/mail/ngx_mail_ssl_module.c
+++ b/src/mail/ngx_mail_ssl_module.c
@@ -682,7 +682,7 @@ ngx_mail_ssl_conf_command_check(ngx_conf_t *cf, void *post, void *data)
 {
 #ifndef SSL_CONF_FLAG_FILE
     return "is not supported on this platform";
-#endif
-
+#else
     return NGX_CONF_OK;
+#endif
 }