fix(router): fix tls_passthrough in expression flavor (#11538)

Fix an issue that protocol `tls_passthrough` can not work with expressions flavor

KAG-2561
See: Kong/kubernetes-ingress-controller#4574 (comment)

(cherry picked from commit 66795cd)

CHANGELOG/unreleased/kong/11538.yaml

@@ -0,0 +1,7 @@
+message: Fix an issue that protocol `tls_passthrough` can not work with expressions flavor
+type: bugfix
+scope: Core
+prs:
+  - 11538
+jiras:
+  - "KAG-2561"

kong/router/expressions.lua

@@ -32,7 +32,9 @@ local function get_exp_and_priority(route)
   -- give the chance for http redirection (301/302/307/308/426)
   -- and allow tcp works with tls
   if protocols and #protocols == 1 and
-    (protocols[1] == "https" or protocols[1] == "tls")
+    (protocols[1] == "https" or
+     protocols[1] == "tls" or
+     protocols[1] == "tls_passthrough")
   then
     return exp, route.priority
   end

spec/01-unit/08-router_spec.lua

@@ -4860,7 +4860,74 @@ end
 do
   local flavor = "expressions"
 
-  describe("Router (flavor = " .. flavor .. ")", function()
+  describe("Router (flavor = " .. flavor .. ") [stream]", function()
+    reload_router(flavor, "stream")
+
+    local use_case, router
+
+    local service =  {
+      name = "service-invalid",
+      protocol = "tcp",
+    }
+
+    lazy_setup(function()
+      use_case = {
+        {
+          service = service,
+          route   = {
+            id = "e8fb37f1-102d-461e-9c51-6608a6bb8101",
+            protocols = { "tls" },
+            expression = [[tls.sni == "www.example.com"]],
+            priority = 100,
+          },
+        },
+        {
+          service = service,
+          route   = {
+            id = "e8fb37f1-102d-461e-9c51-6608a6bb8102",
+            protocols = { "tls_passthrough" },
+            expression = [[tls.sni == "www.example.org"]],
+            priority = 100,
+          },
+        },
+      }
+
+      router = assert(new_router(use_case))
+    end)
+
+    it("exec() should match tls with tls.sni", function()
+      local _ngx = {
+        var = {
+          remote_port = 1000,
+          server_port = 1000,
+          ssl_preread_server_name = "www.example.com",
+        },
+      }
+      router._set_ngx(_ngx)
+      local match_t = router:exec()
+      assert.truthy(match_t)
+
+      assert.same(use_case[1].route, match_t.route)
+    end)
+
+    it("exec() should match tls_passthrough with tls.sni", function()
+      local _ngx = {
+        var = {
+          remote_port = 1000,
+          server_port = 1000,
+          ssl_preread_server_name = "www.example.org",
+        },
+      }
+      router._set_ngx(_ngx)
+      local match_t = router:exec()
+      assert.truthy(match_t)
+
+      assert.same(use_case[2].route, match_t.route)
+    end)
+
+  end)
+
+  describe("Router (flavor = " .. flavor .. ") [http]", function()
     reload_router(flavor)
 
     local use_case, router

spec/02-integration/05-proxy/02-router_spec.lua

@@ -1410,7 +1410,7 @@ for _, strategy in helpers.each_strategy() do
         end
       end)
 
-      it_trad_only("matches a Route based on its 'snis' attribute", function()
+      it("matches a Route based on its 'snis' attribute", function()
         -- config propagates to stream subsystems not instantly
         -- try up to 10 seconds with step of 2 seconds
         -- in vagrant it takes around 6 seconds