[libretiny] Tune oversized lwIP defaults for ESPHome (#14186)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

esphome/components/api/__init__.py

@@ -233,8 +233,8 @@ def _consume_api_sockets(config: ConfigType) -> ConfigType:
 
     # API needs 1 listening socket + typically 3 concurrent client connections
     # (not max_connections, which is the upper limit rarely reached)
-    sockets_needed = 1 + 3
+    socket.consume_sockets(3, "api")(config)
-    socket.consume_sockets(sockets_needed, "api")(config)
+    socket.consume_sockets(1, "api", socket.SocketType.TCP_LISTEN)(config)
     return config
 
 

esphome/components/captive_portal/__init__.py

@@ -76,13 +76,15 @@ def _final_validate(config: ConfigType) -> ConfigType:
 
     # Register socket needs for DNS server and additional HTTP connections
     # - 1 UDP socket for DNS server
-    # - 3 additional TCP sockets for captive portal detection probes + configuration requests
+    # - 3 TCP sockets for captive portal detection probes + configuration requests
     #   OS captive portal detection makes multiple probe requests that stay in TIME_WAIT.
     #   Need headroom for actual user configuration requests.
     #   LRU purging will reclaim idle sockets to prevent exhaustion from repeated attempts.
+    # The listening socket is registered by web_server_base (shared HTTP server).
     from esphome.components import socket
 
-    socket.consume_sockets(4, "captive_portal")(config)
+    socket.consume_sockets(3, "captive_portal")(config)
+    socket.consume_sockets(1, "captive_portal", socket.SocketType.UDP)(config)
 
     return config
 

esphome/components/esp32/__init__.py

@@ -1258,21 +1258,15 @@ def _configure_lwip_max_sockets(conf: dict) -> None:
     This function runs in to_code() after all components have registered their socket needs.
     User-provided sdkconfig_options take precedence.
     """
-    from esphome.components.socket import KEY_SOCKET_CONSUMERS
+    from esphome.components.socket import get_socket_counts
 
     # Check if user manually specified CONFIG_LWIP_MAX_SOCKETS
     user_max_sockets = conf[CONF_SDKCONFIG_OPTIONS].get("CONFIG_LWIP_MAX_SOCKETS")
 
-    socket_consumers: dict[str, int] = CORE.data.get(KEY_SOCKET_CONSUMERS, {})
+    # CONFIG_LWIP_MAX_SOCKETS is a single VFS socket pool shared by all socket
-    total_sockets = sum(socket_consumers.values())
+    # types (TCP clients, TCP listeners, and UDP). Include all three counts.
-
+    sc = get_socket_counts()
-    # Early return if no sockets registered and no user override
+    total_sockets = sc.tcp + sc.udp + sc.tcp_listen
-    if total_sockets == 0 and user_max_sockets is None:
-        return
-
-    components_list = ", ".join(
-        f"{name}={count}" for name, count in sorted(socket_consumers.items())
-    )
 
     # User specified their own value - respect it but warn if insufficient
     if user_max_sockets is not None:
@@ -1281,22 +1275,23 @@ def _configure_lwip_max_sockets(conf: dict) -> None:
             user_max_sockets,
         )
 
-        # Warn if user's value is less than what components need
+        user_sockets_int = 0
-        if total_sockets > 0:
+        with contextlib.suppress(ValueError, TypeError):
-            user_sockets_int = 0
+            user_sockets_int = int(user_max_sockets)
-            with contextlib.suppress(ValueError, TypeError):
-                user_sockets_int = int(user_max_sockets)
 
-            if user_sockets_int < total_sockets:
+        if user_sockets_int < total_sockets:
-                _LOGGER.warning(
+            _LOGGER.warning(
-                    "CONFIG_LWIP_MAX_SOCKETS is set to %d but your configuration "
+                "CONFIG_LWIP_MAX_SOCKETS is set to %d but your configuration "
-                    "needs %d sockets (registered: %s). You may experience socket "
+                "needs %d sockets (%d TCP + %d UDP + %d TCP_LISTEN). You may "
-                    "exhaustion errors. Consider increasing to at least %d.",
+                "experience socket exhaustion errors. Consider increasing to "
-                    user_sockets_int,
+                "at least %d.",
-                    total_sockets,
+                user_sockets_int,
-                    components_list,
+                total_sockets,
-                    total_sockets,
+                sc.tcp,
-                )
+                sc.udp,
+                sc.tcp_listen,
+                total_sockets,
+            )
         # User's value already added via sdkconfig_options processing
         return
 
@@ -1305,11 +1300,19 @@ def _configure_lwip_max_sockets(conf: dict) -> None:
     max_sockets = max(DEFAULT_MAX_SOCKETS, total_sockets)
 
     log_level = logging.INFO if max_sockets > DEFAULT_MAX_SOCKETS else logging.DEBUG
+    sock_min = " (min)" if max_sockets > total_sockets else ""
     _LOGGER.log(
         log_level,
-        "Setting CONFIG_LWIP_MAX_SOCKETS to %d (registered: %s)",
+        "Setting CONFIG_LWIP_MAX_SOCKETS to %d%s "
+        "(TCP=%d [%s], UDP=%d [%s], TCP_LISTEN=%d [%s])",
         max_sockets,
-        components_list,
+        sock_min,
+        sc.tcp,
+        sc.tcp_details,
+        sc.udp,
+        sc.udp_details,
+        sc.tcp_listen,
+        sc.tcp_listen_details,
     )
 
     add_idf_sdkconfig_option("CONFIG_LWIP_MAX_SOCKETS", max_sockets)

esphome/components/esp32_camera_web_server/__init__.py

@@ -20,8 +20,10 @@ def _consume_camera_web_server_sockets(config: ConfigType) -> ConfigType:
     from esphome.components import socket
 
     # Each camera web server instance needs 1 listening socket + 2 client connections
-    sockets_needed = 3
+    socket.consume_sockets(2, "esp32_camera_web_server")(config)
-    socket.consume_sockets(sockets_needed, "esp32_camera_web_server")(config)
+    socket.consume_sockets(1, "esp32_camera_web_server", socket.SocketType.TCP_LISTEN)(
+        config
+    )
     return config
 
 

esphome/components/esphome/ota/__init__.py

@@ -97,8 +97,9 @@ def _consume_ota_sockets(config: ConfigType) -> ConfigType:
     """Register socket needs for OTA component."""
     from esphome.components import socket
 
-    # OTA needs 1 listening socket (client connections are temporary during updates)
+    # OTA needs 1 listening socket. The active transfer connection during an update
-    socket.consume_sockets(1, "ota")(config)
+    # uses a TCP PCB from the general pool, covered by MIN_TCP_SOCKETS headroom.
+    socket.consume_sockets(1, "ota", socket.SocketType.TCP_LISTEN)(config)
     return config
 
 

esphome/components/libretiny/__init__.py

@@ -275,6 +275,146 @@ BASE_SCHEMA.add_extra(_detect_variant)
 BASE_SCHEMA.add_extra(_update_core_data)
 
 
+def _configure_lwip(config: dict) -> None:
+    """Configure lwIP options for LibreTiny platforms.
+
+    The BK/RTL/LN SDKs each ship different lwIP defaults. BK72XX defaults are
+    wildly oversized for ESPHome's IoT use case, causing OOM on BK7231N.
+    RTL87XX and LN882H have more conservative defaults but still need tuning
+    for ESPHome's socket usage patterns.
+
+    See https://github.com/esphome/esphome/issues/14095
+
+    Comparison of SDK defaults vs ESPHome targets (TCP_MSS=1460 on all LT):
+
+    Setting                   ESP8266  ESP32  BK SDK   RTL SDK  LN SDK   New
+    ────────────────────────────────────────────────────────────────────────────
+    TCP_SND_BUF               2×MSS   4×MSS  10×MSS   5×MSS    7×MSS    4×MSS
+    TCP_WND                   4×MSS   4×MSS  3/10×MSS 2×MSS    3×MSS    4×MSS
+    MEM_LIBC_MALLOC           1       1      0        0        1        1
+    MEMP_MEM_MALLOC           1       1      0        0        0        1
+    MEM_SIZE                  N/A*    N/A*   16/32KB  5KB      N/A*     N/A* BK
+    PBUF_POOL_SIZE            10      16     3/10     20       20       10 BK
+    MAX_SOCKETS_TCP           5       16     12       —**      —**      dynamic
+    MAX_SOCKETS_UDP           4       16     22       —**      —**      dynamic
+    TCP_SND_QUEUELEN          ~8      17     20       20       35       17
+    MEMP_NUM_TCP_SEG          10      16     40       20       =qlen    17
+    MEMP_NUM_TCP_PCB          5       16     12       10       8        =TCP
+    MEMP_NUM_TCP_PCB_LISTEN   4       16     4        5        3        dynamic
+    MEMP_NUM_UDP_PCB          4       16     25***    7****    7****    =UDP
+    MEMP_NUM_NETCONN          0       10     38       4*****   =sum     =sum
+    MEMP_NUM_NETBUF           0       2      16       2*****   8        4
+    MEMP_NUM_TCPIP_MSG_INPKT  4       8      16       8*****   12       8
+
+    * ESP8266/ESP32/LN882H use MEM_LIBC_MALLOC=1 (system heap, no dedicated pool).
+      ESP8266/ESP32 also use MEMP_MEM_MALLOC=1 (MEMP pools from heap, not static).
+    ** RTL/LN SDKs don't define MAX_SOCKETS_TCP/UDP (LibreTiny-specific).
+    *** BK LT overlay: MAX_SOCKETS_UDP+2+1 = 25.
+    **** RTL/LN LT overlay overrides to flat 7.
+    ***** Not defined in RTL SDK — lwIP opt.h defaults shown.
+    "dynamic" = auto-calculated from component socket registrations via
+    socket.get_socket_counts() with minimums of 8 TCP / 6 UDP.
+    """
+    from esphome.components.socket import (
+        MIN_TCP_LISTEN_SOCKETS,
+        MIN_TCP_SOCKETS,
+        MIN_UDP_SOCKETS,
+        get_socket_counts,
+    )
+
+    sc = get_socket_counts()
+    # Apply platform minimums — ensure headroom for ESPHome's needs
+    tcp_sockets = max(MIN_TCP_SOCKETS, sc.tcp)
+    udp_sockets = max(MIN_UDP_SOCKETS, sc.udp)
+    # Listening sockets — registered by components (api, ota, web_server_base, etc.)
+    # Not all components register yet, so ensure a minimum for baseline operation.
+    listening_tcp = max(MIN_TCP_LISTEN_SOCKETS, sc.tcp_listen)
+
+    # TCP_SND_BUF: ESPAsyncWebServer allocates malloc(tcp_sndbuf()) per
+    # response chunk. At 10×MSS=14.6KB (BK default) this causes OOM (#14095).
+    # 4×MSS=5,840 matches ESP32. RTL(5×) and LN(7×) are close already.
+    tcp_snd_buf = "(4*TCP_MSS)"  # BK: 10×MSS, RTL: 5×MSS, LN: 7×MSS
+
+    # TCP_WND: receive window. 4×MSS matches ESP32.
+    # RTL SDK uses only 2×MSS; increasing to 4× is safe and improves throughput.
+    tcp_wnd = "(4*TCP_MSS)"  # BK: 10×MSS, RTL: 2×MSS, LN: 3×MSS
+
+    # TCP_SND_QUEUELEN: max pbufs queued for send buffer
+    # ESP-IDF formula: (4 * TCP_SND_BUF + (TCP_MSS - 1)) / TCP_MSS
+    # With 4×MSS: (4*5840 + 1459) / 1460 = 17 — match ESP32
+    tcp_snd_queuelen = 17  # BK: 20, RTL: 20, LN: 35
+    # MEMP_NUM_TCP_SEG: segment pool, must be >= TCP_SND_QUEUELEN (lwIP sanity check)
+    memp_num_tcp_seg = tcp_snd_queuelen  # BK: 40, RTL: 20, LN: =qlen
+
+    lwip_opts: list[str] = [
+        # Disable statistics — not needed for production, saves RAM
+        "LWIP_STATS=0",  # BK: 1, RTL: 0 already, LN: 0 already
+        "MEM_STATS=0",
+        "MEMP_STATS=0",
+        # TCP send buffer — 4×MSS matches ESP32
+        f"TCP_SND_BUF={tcp_snd_buf}",
+        # TCP receive window — 4×MSS matches ESP32
+        f"TCP_WND={tcp_wnd}",
+        # Socket counts — auto-calculated from component registrations
+        f"MAX_SOCKETS_TCP={tcp_sockets}",
+        f"MAX_SOCKETS_UDP={udp_sockets}",
+        # Listening sockets — BK SDK uses this to derive MEMP_NUM_TCP_PCB_LISTEN;
+        # RTL/LN don't use it, but we set MEMP_NUM_TCP_PCB_LISTEN explicitly below.
+        f"MAX_LISTENING_SOCKETS_TCP={listening_tcp}",
+        # Queued segment limits — derived from 4×MSS buffer size
+        f"TCP_SND_QUEUELEN={tcp_snd_queuelen}",
+        f"MEMP_NUM_TCP_SEG={memp_num_tcp_seg}",  # must be >= queuelen
+        # PCB pools — active connections + listening sockets
+        f"MEMP_NUM_TCP_PCB={tcp_sockets}",  # BK: 12, RTL: 10, LN: 8
+        f"MEMP_NUM_TCP_PCB_LISTEN={listening_tcp}",  # BK: =MAX_LISTENING, RTL: 5, LN: 3
+        # UDP PCB pool — includes wifi.lwip_internal (DHCP + DNS)
+        f"MEMP_NUM_UDP_PCB={udp_sockets}",  # BK: 25, RTL/LN: 7 via LT
+        # Netconn pool — each socket (active + listening) needs a netconn
+        f"MEMP_NUM_NETCONN={tcp_sockets + udp_sockets + listening_tcp}",
+        # Netbuf pool
+        "MEMP_NUM_NETBUF=4",  # BK: 16, RTL: 2 (opt.h), LN: 8
+        # Inbound message pool
+        "MEMP_NUM_TCPIP_MSG_INPKT=8",  # BK: 16, RTL: 8 (opt.h), LN: 12
+    ]
+
+    # Use system heap for all lwIP allocations on all LibreTiny platforms.
+    # - MEM_LIBC_MALLOC=1: Use system heap instead of dedicated lwIP heap.
+    #   LN882H already ships with this. BK SDK defaults to a 16/32KB dedicated
+    #   pool that fragments during OTA. RTL SDK defaults to a 5KB pool.
+    #   All three SDKs wire malloc → pvPortMalloc (FreeRTOS thread-safe heap).
+    # - MEMP_MEM_MALLOC=1: Allocate MEMP pools from heap on demand instead
+    #   of static arrays. Saves ~20KB RAM on BK72XX. Safe because WiFi
+    #   receive paths run in task context, not ISR context. ESP32 and ESP8266
+    #   both ship with MEMP_MEM_MALLOC=1.
+    lwip_opts.append("MEM_LIBC_MALLOC=1")
+    lwip_opts.append("MEMP_MEM_MALLOC=1")
+
+    # BK72XX-specific: PBUF_POOL_SIZE override
+    # BK SDK "reduced plan" sets this to only 3 — too few for multiple
+    # concurrent connections (API + web_server + OTA). BK default plan
+    # uses 10; match that. RTL(20) and LN(20) need no override.
+    # With MEMP_MEM_MALLOC=1, this is a max count (allocated on demand).
+    if CORE.is_bk72xx:
+        lwip_opts.append("PBUF_POOL_SIZE=10")
+
+    tcp_min = " (min)" if tcp_sockets > sc.tcp else ""
+    udp_min = " (min)" if udp_sockets > sc.udp else ""
+    listen_min = " (min)" if listening_tcp > sc.tcp_listen else ""
+    _LOGGER.info(
+        "Configuring lwIP: TCP=%d%s [%s], UDP=%d%s [%s], TCP_LISTEN=%d%s [%s]",
+        tcp_sockets,
+        tcp_min,
+        sc.tcp_details,
+        udp_sockets,
+        udp_min,
+        sc.udp_details,
+        listening_tcp,
+        listen_min,
+        sc.tcp_listen_details,
+    )
+    cg.add_platformio_option("custom_options.lwip", lwip_opts)
+
+
 # pylint: disable=use-dict-literal
 async def component_to_code(config):
     var = cg.new_Pvariable(config[CONF_ID])
@@ -389,11 +529,12 @@ async def component_to_code(config):
             "custom_options.sys_config#h", _BK7231N_SYS_CONFIG_OPTIONS
         )
 
-    # Disable LWIP statistics to save RAM - not needed in production
+    # Tune lwIP for ESPHome's actual needs.
-    # Must explicitly disable all sub-stats to avoid redefinition warnings
+    # The SDK defaults (TCP_SND_BUF=10*MSS, MAX_SOCKETS_TCP=12, MEM_SIZE=32KB)
-    cg.add_platformio_option(
+    # are wildly oversized for an IoT device. ESPAsyncWebServer allocates
-        "custom_options.lwip",
+    # malloc(tcp_sndbuf()) per response chunk — at 14.6KB this causes silent
-        ["LWIP_STATS=0", "MEM_STATS=0", "MEMP_STATS=0"],
+    # OOM on memory-constrained chips like BK7231N.
-    )
+    # See https://github.com/esphome/esphome/issues/14095
+    _configure_lwip(config)
 
     await cg.register_component(var, config)

esphome/components/mdns/__init__.py

@@ -56,7 +56,7 @@ def _consume_mdns_sockets(config: ConfigType) -> ConfigType:
     from esphome.components import socket
 
     # mDNS needs 2 sockets (IPv4 + IPv6 multicast)
-    socket.consume_sockets(2, "mdns")(config)
+    socket.consume_sockets(2, "mdns", socket.SocketType.UDP)(config)
     return config
 
 

esphome/components/socket/__init__.py

@@ -1,9 +1,14 @@
 from collections.abc import Callable, MutableMapping
+from dataclasses import dataclass
+from enum import StrEnum
+import logging
 
 import esphome.codegen as cg
 import esphome.config_validation as cv
 from esphome.core import CORE
 
+_LOGGER = logging.getLogger(__name__)
+
 CODEOWNERS = ["@esphome/core"]
 
 CONF_IMPLEMENTATION = "implementation"
@@ -13,33 +18,110 @@ IMPLEMENTATION_BSD_SOCKETS = "bsd_sockets"
 
 # Socket tracking infrastructure
 # Components register their socket needs and platforms read this to configure appropriately
-KEY_SOCKET_CONSUMERS = "socket_consumers"
+KEY_SOCKET_CONSUMERS_TCP = "socket_consumers_tcp"
+KEY_SOCKET_CONSUMERS_UDP = "socket_consumers_udp"
+KEY_SOCKET_CONSUMERS_TCP_LISTEN = "socket_consumers_tcp_listen"
+
+# Recommended minimum socket counts.
+# Platforms should apply these (or their own) on top of get_socket_counts().
+# These cover minimal configs (e.g. api-only without web_server).
+# When web_server is present, its 5 registered sockets push past the TCP minimum.
+MIN_TCP_SOCKETS = 8
+MIN_UDP_SOCKETS = 6
+# Minimum listening sockets — at least api + ota baseline.
+MIN_TCP_LISTEN_SOCKETS = 2
 
 # Wake loop threadsafe support tracking
 KEY_WAKE_LOOP_THREADSAFE_REQUIRED = "wake_loop_threadsafe_required"
 
 
+class SocketType(StrEnum):
+    TCP = "tcp"
+    UDP = "udp"
+    TCP_LISTEN = "tcp_listen"
+
+
+_SOCKET_TYPE_KEYS = {
+    SocketType.TCP: KEY_SOCKET_CONSUMERS_TCP,
+    SocketType.UDP: KEY_SOCKET_CONSUMERS_UDP,
+    SocketType.TCP_LISTEN: KEY_SOCKET_CONSUMERS_TCP_LISTEN,
+}
+
+
 def consume_sockets(
-    value: int, consumer: str
+    value: int, consumer: str, socket_type: SocketType = SocketType.TCP
 ) -> Callable[[MutableMapping], MutableMapping]:
     """Register socket usage for a component.
 
     Args:
         value: Number of sockets needed by the component
         consumer: Name of the component consuming the sockets
+        socket_type: Type of socket (SocketType.TCP, SocketType.UDP, or SocketType.TCP_LISTEN)
 
     Returns:
         A validator function that records the socket usage
     """
+    typed_key = _SOCKET_TYPE_KEYS[socket_type]
 
     def _consume_sockets(config: MutableMapping) -> MutableMapping:
-        consumers: dict[str, int] = CORE.data.setdefault(KEY_SOCKET_CONSUMERS, {})
+        consumers: dict[str, int] = CORE.data.setdefault(typed_key, {})
         consumers[consumer] = consumers.get(consumer, 0) + value
         return config
 
     return _consume_sockets
 
 
+def _format_consumers(consumers: dict[str, int]) -> str:
+    """Format consumer dict as 'name=count, ...' or 'none'."""
+    if not consumers:
+        return "none"
+    return ", ".join(f"{name}={count}" for name, count in sorted(consumers.items()))
+
+
+@dataclass(frozen=True)
+class SocketCounts:
+    """Socket counts and component details for platform configuration."""
+
+    tcp: int
+    udp: int
+    tcp_listen: int
+    tcp_details: str
+    udp_details: str
+    tcp_listen_details: str
+
+
+def get_socket_counts() -> SocketCounts:
+    """Return socket counts and component details for platform configuration.
+
+    Platforms call this during code generation to configure lwIP socket limits.
+    All components will have registered their needs by then.
+
+    Platforms should apply their own minimums on top of these values.
+    """
+    tcp_consumers = CORE.data.get(KEY_SOCKET_CONSUMERS_TCP, {})
+    udp_consumers = CORE.data.get(KEY_SOCKET_CONSUMERS_UDP, {})
+    tcp_listen_consumers = CORE.data.get(KEY_SOCKET_CONSUMERS_TCP_LISTEN, {})
+    tcp = sum(tcp_consumers.values())
+    udp = sum(udp_consumers.values())
+    tcp_listen = sum(tcp_listen_consumers.values())
+
+    tcp_details = _format_consumers(tcp_consumers)
+    udp_details = _format_consumers(udp_consumers)
+    tcp_listen_details = _format_consumers(tcp_listen_consumers)
+    _LOGGER.debug(
+        "Socket counts: TCP=%d (%s), UDP=%d (%s), TCP_LISTEN=%d (%s)",
+        tcp,
+        tcp_details,
+        udp,
+        udp_details,
+        tcp_listen,
+        tcp_listen_details,
+    )
+    return SocketCounts(
+        tcp, udp, tcp_listen, tcp_details, udp_details, tcp_listen_details
+    )
+
+
 def require_wake_loop_threadsafe() -> None:
     """Mark that wake_loop_threadsafe support is required by a component.
 
@@ -66,7 +148,7 @@ def require_wake_loop_threadsafe() -> None:
         CORE.data[KEY_WAKE_LOOP_THREADSAFE_REQUIRED] = True
         cg.add_define("USE_WAKE_LOOP_THREADSAFE")
         # Consume 1 socket for the shared wake notification socket
-        consume_sockets(1, "socket.wake_loop_threadsafe")({})
+        consume_sockets(1, "socket.wake_loop_threadsafe", SocketType.UDP)({})
 
 
 CONFIG_SCHEMA = cv.Schema(

esphome/components/udp/__init__.py

@@ -73,7 +73,7 @@ def _consume_udp_sockets(config: ConfigType) -> ConfigType:
 
     # UDP uses up to 2 sockets: 1 broadcast + 1 listen
     # Whether each is used depends on code generation, so register worst case
-    socket.consume_sockets(2, "udp")(config)
+    socket.consume_sockets(2, "udp", socket.SocketType.UDP)(config)
     return config
 
 

esphome/components/web_server/__init__.py

@@ -144,11 +144,11 @@ def _consume_web_server_sockets(config: ConfigType) -> ConfigType:
     """Register socket needs for web_server component."""
     from esphome.components import socket
 
-    # Web server needs 1 listening socket + typically 5 concurrent client connections
+    # Web server needs typically 5 concurrent client connections
     # (browser opens connections for page resources, SSE event stream, and POST
     # requests for entity control which may linger before closing)
-    sockets_needed = 6
+    # The listening socket is registered by web_server_base (shared with captive_portal)
-    socket.consume_sockets(sockets_needed, "web_server")(config)
+    socket.consume_sockets(5, "web_server")(config)
     return config
 
 

esphome/components/web_server_base/__init__.py

@@ -23,10 +23,27 @@ web_server_base_ns = cg.esphome_ns.namespace("web_server_base")
 WebServerBase = web_server_base_ns.class_("WebServerBase")
 
 CONF_WEB_SERVER_BASE_ID = "web_server_base_id"
-CONFIG_SCHEMA = cv.Schema(
+
-    {
+
-        cv.GenerateID(): cv.declare_id(WebServerBase),
+def _consume_web_server_base_sockets(config):
-    }
+    """Register the shared listening socket for the HTTP server.
+
+    web_server_base is the shared HTTP server used by web_server and captive_portal.
+    The listening socket is registered here rather than in each consumer.
+    """
+    from esphome.components import socket
+
+    socket.consume_sockets(1, "web_server_base", socket.SocketType.TCP_LISTEN)(config)
+    return config
+
+
+CONFIG_SCHEMA = cv.All(
+    cv.Schema(
+        {
+            cv.GenerateID(): cv.declare_id(WebServerBase),
+        }
+    ),
+    _consume_web_server_base_sockets,
 )
 
 

esphome/components/wifi/__init__.py

@@ -58,6 +58,7 @@ from esphome.const import (
 )
 from esphome.core import CORE, CoroPriority, HexInt, coroutine_with_priority
 import esphome.final_validate as fv
+from esphome.types import ConfigType
 
 from . import wpa2_eap
 
@@ -269,9 +270,28 @@ def final_validate(config):
         )
 
 
+def _consume_wifi_sockets(config: ConfigType) -> ConfigType:
+    """Register UDP PCBs used internally by lwIP for DHCP and DNS.
+
+    Only needed on LibreTiny where we directly set MEMP_NUM_UDP_PCB (the raw
+    PCB pool shared by both application sockets and lwIP internals like DHCP/DNS).
+    On ESP32, CONFIG_LWIP_MAX_SOCKETS only controls the POSIX socket layer —
+    DHCP/DNS use raw udp_new() which bypasses it entirely.
+    """
+    if not (CORE.is_bk72xx or CORE.is_rtl87xx or CORE.is_ln882x):
+        return config
+    from esphome.components import socket
+
+    # lwIP allocates UDP PCBs for DHCP client and DNS resolver internally.
+    # These are not application sockets but consume MEMP_NUM_UDP_PCB pool entries.
+    socket.consume_sockets(2, "wifi.lwip_internal", socket.SocketType.UDP)(config)
+    return config
+
+
 FINAL_VALIDATE_SCHEMA = cv.All(
     final_validate,
     validate_variant,
+    _consume_wifi_sockets,
 )
 
 

tests/components/socket/test_wake_loop_threadsafe.py

@@ -66,12 +66,12 @@ def test_require_wake_loop_threadsafe__no_networking_does_not_consume_socket() -
     CORE.config = {"logger": {}}
 
     # Track initial socket consumer state
-    initial_consumers = CORE.data.get(socket.KEY_SOCKET_CONSUMERS, {})
+    initial_udp = CORE.data.get(socket.KEY_SOCKET_CONSUMERS_UDP, {})
 
     # Call require_wake_loop_threadsafe
     socket.require_wake_loop_threadsafe()
 
     # Verify no socket was consumed
-    consumers = CORE.data.get(socket.KEY_SOCKET_CONSUMERS, {})
+    udp_consumers = CORE.data.get(socket.KEY_SOCKET_CONSUMERS_UDP, {})
-    assert "socket.wake_loop_threadsafe" not in consumers
+    assert "socket.wake_loop_threadsafe" not in udp_consumers
-    assert consumers == initial_consumers
+    assert udp_consumers == initial_udp