From d1d3d256a9663c87a833efe6efc4a73c558ad605 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Thu, 19 Feb 2026 00:37:23 -0600
Subject: [PATCH] [socket] Log error when UDP socket requested on LWIP TCP-only
 platforms

The LWIP raw socket factory only supports TCP but silently ignored the
type parameter, returning a TCP socket for SOCK_DGRAM requests. This
caused components expecting UDP to fail silently with no indication of
why. Return nullptr with EPROTOTYPE and log an error instead.
---
 esphome/components/socket/lwip_raw_tcp_impl.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/esphome/components/socket/lwip_raw_tcp_impl.cpp b/esphome/components/socket/lwip_raw_tcp_impl.cpp
index aa37386d70..6e95f5bc7a 100644
--- a/esphome/components/socket/lwip_raw_tcp_impl.cpp
+++ b/esphome/components/socket/lwip_raw_tcp_impl.cpp
@@ -680,6 +680,11 @@ class LWIPRawListenImpl final : public LWIPRawImpl {
 };
 
 std::unique_ptr<Socket> socket(int domain, int type, int protocol) {
+  if (type != SOCK_STREAM) {
+    ESP_LOGE(TAG, "UDP sockets not supported on this platform, use WiFiUDP");
+    errno = EPROTOTYPE;
+    return nullptr;
+  }
   auto *pcb = tcp_new();
   if (pcb == nullptr)
     return nullptr;