From: vinaykumar-1591 <v.tokala@f5.com>
Date: Thu, 18 Jun 2026 06:06:33 +0000 (-0700)
Subject: Upstream: Upgrade header processing
X-Git-Url: http://git.kaiwu.me/%7B@url%7D?a=commitdiff_plain;h=3f720dc7845eb21594788fe12cc9e37e5d930161;p=nginx.git

Upstream: Upgrade header processing

Pass Upgrade through for HTTP/1.x clients only: both for active
connection upgrades (101 Switching Protocols) and for advertising
available upgrades in other responses (RFC 9110 Section 7.8).
Strip it for HTTP/2+ clients where connection-specific headers
are forbidden (RFC 9113 Section 8.2.2, RFC 9114 Section 4.2).
---

diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
index bb8964add..bd6ae5f07 100644
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -156,6 +156,8 @@ static ngx_int_t ngx_http_upstream_rewrite_set_cookie(ngx_http_request_t *r,
     ngx_table_elt_t *h, ngx_uint_t offset);
 static ngx_int_t ngx_http_upstream_copy_allow_ranges(ngx_http_request_t *r,
     ngx_table_elt_t *h, ngx_uint_t offset);
+static ngx_int_t ngx_http_upstream_copy_upgrade(ngx_http_request_t *r,
+    ngx_table_elt_t *h, ngx_uint_t offset);
 
 static ngx_int_t ngx_http_upstream_add_variables(ngx_conf_t *cf);
 static ngx_int_t ngx_http_upstream_addr_variable(ngx_http_request_t *r,
@@ -278,6 +280,10 @@ static ngx_http_upstream_header_t  ngx_http_upstream_headers_in[] = {
                  ngx_http_upstream_copy_allow_ranges,
                  offsetof(ngx_http_headers_out_t, accept_ranges), 1 },
 
+    { ngx_string("Upgrade"),
+                 ngx_http_upstream_ignore_header_line, 0,
+                 ngx_http_upstream_copy_upgrade, 0, 0 },
+
     { ngx_string("Content-Range"),
                  ngx_http_upstream_ignore_header_line, 0,
                  ngx_http_upstream_copy_header_line,
@@ -5868,6 +5874,27 @@ ngx_http_upstream_copy_allow_ranges(ngx_http_request_t *r,
 }
 
 
+static ngx_int_t
+ngx_http_upstream_copy_upgrade(ngx_http_request_t *r, ngx_table_elt_t *h,
+    ngx_uint_t offset)
+{
+    ngx_table_elt_t  *ho;
+
+    if (r->http_version >= NGX_HTTP_VERSION_20) {
+        return NGX_OK;
+    }
+
+    ho = ngx_list_push(&r->headers_out.headers);
+    if (ho == NULL) {
+        return NGX_ERROR;
+    }
+
+    *ho = *h;
+
+    return NGX_OK;
+}
+
+
 static ngx_int_t
 ngx_http_upstream_add_variables(ngx_conf_t *cf)
 {