--- a/src/http/ngx_http_header_filter_module.c
+++ b/src/http/ngx_http_header_filter_module.c
@@ -53,7 +53,7 @@ static ngx_str_t ngx_http_status_lines[]
 
     ngx_string("200 OK"),
     ngx_string("201 Created"),
-    ngx_null_string,  /* "202 Accepted" */
+    ngx_string("202 Accepted"),
     ngx_null_string,  /* "203 Non-Authoritative Information" */
     ngx_string("204 No Content"),
     ngx_null_string,  /* "205 Reset Content" */
@@ -68,7 +68,7 @@ static ngx_str_t ngx_http_status_lines[]
 
     ngx_string("301 Moved Permanently"),
     ngx_string("302 Moved Temporarily"),
-    ngx_null_string,  /* "303 See Other" */
+    ngx_string("303 See Other"),
     ngx_string("304 Not Modified"),
 
     /* ngx_null_string, */  /* "305 Use Proxy" */
@@ -170,6 +170,10 @@ ngx_http_header_filter(ngx_http_request_
 #endif
     u_char                     addr[NGX_SOCKADDR_STRLEN];
 
+    if (r->header_sent) {
+        return NGX_OK;
+    }
+
     r->header_sent = 1;
 
     if (r != r->main) {
@@ -218,8 +222,7 @@ ngx_http_header_filter(ngx_http_request_
 
             if (status == NGX_HTTP_NO_CONTENT) {
                 r->header_only = 1;
-                r->headers_out.content_type.len = 0;
-                r->headers_out.content_type.data = NULL;
+                ngx_str_null(&r->headers_out.content_type);
                 r->headers_out.last_modified_time = -1;
                 r->headers_out.last_modified = NULL;
                 r->headers_out.content_length = NULL;
@@ -338,6 +341,11 @@ ngx_http_header_filter(ngx_http_request_
             port = ntohs(sin6->sin6_port);
             break;
 #endif
+#if (NGX_HAVE_UNIX_DOMAIN)
+        case AF_UNIX:
+            port = 0;
+            break;
+#endif
         default: /* AF_INET */
             sin = (struct sockaddr_in *) c->local_sockaddr;
             port = ntohs(sin->sin_port);
@@ -366,8 +374,7 @@ ngx_http_header_filter(ngx_http_request_
         }
 
     } else {
-        host.len = 0;
-        host.data = NULL;
+        ngx_str_null(&host);
         port = 0;
     }
 
@@ -534,8 +541,7 @@ ngx_http_header_filter(ngx_http_request_
 
         r->headers_out.location->value.len = b->last - p;
         r->headers_out.location->value.data = p;
-        r->headers_out.location->key.len = sizeof("Location") - 1;
-        r->headers_out.location->key.data = (u_char *) "Location";
+        ngx_str_set(&r->headers_out.location->key, "Location");
 
         *b->last++ = CR; *b->last++ = LF;
     }