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+/**
+ * @file
+ *
+ * lwIP Options Configuration
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+/*
+ * NOTE: || defined __DOXYGEN__ is a workaround for doxygen bug -
+ * without this, doxygen does not see the actual #define
+ */
+
+#if !defined LWIP_HDR_OPT_H
+#define LWIP_HDR_OPT_H
+
+/*
+ * Include user defined options first. Anything not defined in these files
+ * will be set to standard values. Override anything you don't like!
+ */
+#include "lwipopts.h"
+#include "lwip/debug.h"
+
+/**
+ * @defgroup lwip_opts Options (lwipopts.h)
+ * @ingroup lwip
+ *
+ * @defgroup lwip_opts_debug Debugging
+ * @ingroup lwip_opts
+ *
+ * @defgroup lwip_opts_infrastructure Infrastructure
+ * @ingroup lwip_opts
+ *
+ * @defgroup lwip_opts_callback Callback-style APIs
+ * @ingroup lwip_opts
+ *
+ * @defgroup lwip_opts_threadsafe_apis Thread-safe APIs
+ * @ingroup lwip_opts
+ */
+
+ /*
+ ------------------------------------
+ -------------- NO SYS --------------
+ ------------------------------------
+ */
+/**
+ * @defgroup lwip_opts_nosys NO_SYS
+ * @ingroup lwip_opts_infrastructure
+ * @{
+ */
+/**
+ * NO_SYS==1: Use lwIP without OS-awareness (no thread, semaphores, mutexes or
+ * mboxes). This means threaded APIs cannot be used (socket, netconn,
+ * i.e. everything in the 'api' folder), only the callback-style raw API is
+ * available (and you have to watch out for yourself that you don't access
+ * lwIP functions/structures from more than one context at a time!)
+ */
+#if !defined NO_SYS || defined __DOXYGEN__
+#define NO_SYS 0
+#endif
+/**
+ * @}
+ */
+
+/**
+ * @defgroup lwip_opts_timers Timers
+ * @ingroup lwip_opts_infrastructure
+ * @{
+ */
+/**
+ * LWIP_TIMERS==0: Drop support for sys_timeout and lwip-internal cyclic timers.
+ * (the array of lwip-internal cyclic timers is still provided)
+ * (check NO_SYS_NO_TIMERS for compatibility to old versions)
+ */
+#if !defined LWIP_TIMERS || defined __DOXYGEN__
+#ifdef NO_SYS_NO_TIMERS
+#define LWIP_TIMERS (!NO_SYS || (NO_SYS && !NO_SYS_NO_TIMERS))
+#else
+#define LWIP_TIMERS 1
+#endif
+#endif
+
+/**
+ * LWIP_TIMERS_CUSTOM==1: Provide your own timer implementation.
+ * Function prototypes in timeouts.h and the array of lwip-internal cyclic timers
+ * are still included, but the implementation is not. The following functions
+ * will be required: sys_timeouts_init(), sys_timeout(), sys_untimeout(),
+ * sys_timeouts_mbox_fetch()
+ */
+#if !defined LWIP_TIMERS_CUSTOM || defined __DOXYGEN__
+#define LWIP_TIMERS_CUSTOM 0
+#endif
+/**
+ * @}
+ */
+
+/**
+ * @defgroup lwip_opts_memcpy memcpy
+ * @ingroup lwip_opts_infrastructure
+ * @{
+ */
+/**
+ * MEMCPY: override this if you have a faster implementation at hand than the
+ * one included in your C library
+ */
+#if !defined MEMCPY || defined __DOXYGEN__
+#define MEMCPY(dst,src,len) memcpy(dst,src,len)
+#endif
+
+/**
+ * SMEMCPY: override this with care! Some compilers (e.g. gcc) can inline a
+ * call to memcpy() if the length is known at compile time and is small.
+ */
+#if !defined SMEMCPY || defined __DOXYGEN__
+#define SMEMCPY(dst,src,len) memcpy(dst,src,len)
+#endif
+/**
+ * @}
+ */
+
+/*
+ ------------------------------------
+ ----------- Core locking -----------
+ ------------------------------------
+*/
+/**
+ * @defgroup lwip_opts_lock Core locking and MPU
+ * @ingroup lwip_opts_infrastructure
+ * @{
+ */
+/**
+ * LWIP_MPU_COMPATIBLE: enables special memory management mechanism
+ * which makes lwip able to work on MPU (Memory Protection Unit) system
+ * by not passing stack-pointers to other threads
+ * (this decreases performance as memory is allocated from pools instead
+ * of keeping it on the stack)
+ */
+#if !defined LWIP_MPU_COMPATIBLE || defined __DOXYGEN__
+#define LWIP_MPU_COMPATIBLE 0
+#endif
+
+/**
+ * LWIP_TCPIP_CORE_LOCKING
+ * Creates a global mutex that is held during TCPIP thread operations.
+ * Can be locked by client code to perform lwIP operations without changing
+ * into TCPIP thread using callbacks. See LOCK_TCPIP_CORE() and
+ * UNLOCK_TCPIP_CORE().
+ * Your system should provide mutexes supporting priority inversion to use this.
+ */
+#if !defined LWIP_TCPIP_CORE_LOCKING || defined __DOXYGEN__
+#define LWIP_TCPIP_CORE_LOCKING 1
+#endif
+
+/**
+ * LWIP_TCPIP_CORE_LOCKING_INPUT: when LWIP_TCPIP_CORE_LOCKING is enabled,
+ * this lets tcpip_input() grab the mutex for input packets as well,
+ * instead of allocating a message and passing it to tcpip_thread.
+ *
+ * ATTENTION: this does not work when tcpip_input() is called from
+ * interrupt context!
+ */
+#if !defined LWIP_TCPIP_CORE_LOCKING_INPUT || defined __DOXYGEN__
+#define LWIP_TCPIP_CORE_LOCKING_INPUT 0
+#endif
+
+/**
+ * SYS_LIGHTWEIGHT_PROT==1: enable inter-task protection (and task-vs-interrupt
+ * protection) for certain critical regions during buffer allocation, deallocation
+ * and memory allocation and deallocation.
+ * ATTENTION: This is required when using lwIP from more than one context! If
+ * you disable this, you must be sure what you are doing!
+ */
+#if !defined SYS_LIGHTWEIGHT_PROT || defined __DOXYGEN__
+#define SYS_LIGHTWEIGHT_PROT 1
+#endif
+/**
+ * @}
+ */
+
+/*
+ ------------------------------------
+ ---------- Memory options ----------
+ ------------------------------------
+*/
+/**
+ * @defgroup lwip_opts_mem Heap and memory pools
+ * @ingroup lwip_opts_infrastructure
+ * @{
+ */
+/**
+ * MEM_LIBC_MALLOC==1: Use malloc/free/realloc provided by your C-library
+ * instead of the lwip internal allocator. Can save code size if you
+ * already use it.
+ */
+#if !defined MEM_LIBC_MALLOC || defined __DOXYGEN__
+#define MEM_LIBC_MALLOC 0
+#endif
+
+/**
+ * MEMP_MEM_MALLOC==1: Use mem_malloc/mem_free instead of the lwip pool allocator.
+ * Especially useful with MEM_LIBC_MALLOC but handle with care regarding execution
+ * speed (heap alloc can be much slower than pool alloc) and usage from interrupts
+ * (especially if your netif driver allocates PBUF_POOL pbufs for received frames
+ * from interrupt)!
+ * ATTENTION: Currently, this uses the heap for ALL pools (also for private pools,
+ * not only for internal pools defined in memp_std.h)!
+ */
+#if !defined MEMP_MEM_MALLOC || defined __DOXYGEN__
+#define MEMP_MEM_MALLOC 0
+#endif
+
+/**
+ * MEM_ALIGNMENT: should be set to the alignment of the CPU
+ * 4 byte alignment -> \#define MEM_ALIGNMENT 4
+ * 2 byte alignment -> \#define MEM_ALIGNMENT 2
+ */
+#if !defined MEM_ALIGNMENT || defined __DOXYGEN__
+#define MEM_ALIGNMENT 1
+#endif
+
+/**
+ * MEM_SIZE: the size of the heap memory. If the application will send
+ * a lot of data that needs to be copied, this should be set high.
+ */
+#if !defined MEM_SIZE || defined __DOXYGEN__
+#define MEM_SIZE 1600
+#endif
+
+/**
+ * MEMP_OVERFLOW_CHECK: memp overflow protection reserves a configurable
+ * amount of bytes before and after each memp element in every pool and fills
+ * it with a prominent default value.
+ * MEMP_OVERFLOW_CHECK == 0 no checking
+ * MEMP_OVERFLOW_CHECK == 1 checks each element when it is freed
+ * MEMP_OVERFLOW_CHECK >= 2 checks each element in every pool every time
+ * memp_malloc() or memp_free() is called (useful but slow!)
+ */
+#if !defined MEMP_OVERFLOW_CHECK || defined __DOXYGEN__
+#define MEMP_OVERFLOW_CHECK 0
+#endif
+
+/**
+ * MEMP_SANITY_CHECK==1: run a sanity check after each memp_free() to make
+ * sure that there are no cycles in the linked lists.
+ */
+#if !defined MEMP_SANITY_CHECK || defined __DOXYGEN__
+#define MEMP_SANITY_CHECK 0
+#endif
+
+/**
+ * MEM_USE_POOLS==1: Use an alternative to malloc() by allocating from a set
+ * of memory pools of various sizes. When mem_malloc is called, an element of
+ * the smallest pool that can provide the length needed is returned.
+ * To use this, MEMP_USE_CUSTOM_POOLS also has to be enabled.
+ */
+#if !defined MEM_USE_POOLS || defined __DOXYGEN__
+#define MEM_USE_POOLS 0
+#endif
+
+/**
+ * MEM_USE_POOLS_TRY_BIGGER_POOL==1: if one malloc-pool is empty, try the next
+ * bigger pool - WARNING: THIS MIGHT WASTE MEMORY but it can make a system more
+ * reliable. */
+#if !defined MEM_USE_POOLS_TRY_BIGGER_POOL || defined __DOXYGEN__
+#define MEM_USE_POOLS_TRY_BIGGER_POOL 0
+#endif
+
+/**
+ * MEMP_USE_CUSTOM_POOLS==1: whether to include a user file lwippools.h
+ * that defines additional pools beyond the "standard" ones required
+ * by lwIP. If you set this to 1, you must have lwippools.h in your
+ * include path somewhere.
+ */
+#if !defined MEMP_USE_CUSTOM_POOLS || defined __DOXYGEN__
+#define MEMP_USE_CUSTOM_POOLS 0
+#endif
+
+/**
+ * Set this to 1 if you want to free PBUF_RAM pbufs (or call mem_free()) from
+ * interrupt context (or another context that doesn't allow waiting for a
+ * semaphore).
+ * If set to 1, mem_malloc will be protected by a semaphore and SYS_ARCH_PROTECT,
+ * while mem_free will only use SYS_ARCH_PROTECT. mem_malloc SYS_ARCH_UNPROTECTs
+ * with each loop so that mem_free can run.
+ *
+ * ATTENTION: As you can see from the above description, this leads to dis-/
+ * enabling interrupts often, which can be slow! Also, on low memory, mem_malloc
+ * can need longer.
+ *
+ * If you don't want that, at least for NO_SYS=0, you can still use the following
+ * functions to enqueue a deallocation call which then runs in the tcpip_thread
+ * context:
+ * - pbuf_free_callback(p);
+ * - mem_free_callback(m);
+ */
+#if !defined LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT || defined __DOXYGEN__
+#define LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT 0
+#endif
+/**
+ * @}
+ */
+
+/*
+ ------------------------------------------------
+ ---------- Internal Memory Pool Sizes ----------
+ ------------------------------------------------
+*/
+/**
+ * @defgroup lwip_opts_memp Internal memory pools
+ * @ingroup lwip_opts_infrastructure
+ * @{
+ */
+/**
+ * MEMP_NUM_PBUF: the number of memp struct pbufs (used for PBUF_ROM and PBUF_REF).
+ * If the application sends a lot of data out of ROM (or other static memory),
+ * this should be set high.
+ */
+#if !defined MEMP_NUM_PBUF || defined __DOXYGEN__
+#define MEMP_NUM_PBUF 16
+#endif
+
+/**
+ * MEMP_NUM_RAW_PCB: Number of raw connection PCBs
+ * (requires the LWIP_RAW option)
+ */
+#if !defined MEMP_NUM_RAW_PCB || defined __DOXYGEN__
+#define MEMP_NUM_RAW_PCB 4
+#endif
+
+/**
+ * MEMP_NUM_UDP_PCB: the number of UDP protocol control blocks. One
+ * per active UDP "connection".
+ * (requires the LWIP_UDP option)
+ */
+#if !defined MEMP_NUM_UDP_PCB || defined __DOXYGEN__
+#define MEMP_NUM_UDP_PCB 4
+#endif
+
+/**
+ * MEMP_NUM_TCP_PCB: the number of simultaneously active TCP connections.
+ * (requires the LWIP_TCP option)
+ */
+#if !defined MEMP_NUM_TCP_PCB || defined __DOXYGEN__
+#define MEMP_NUM_TCP_PCB 5
+#endif
+
+/**
+ * MEMP_NUM_TCP_PCB_LISTEN: the number of listening TCP connections.
+ * (requires the LWIP_TCP option)
+ */
+#if !defined MEMP_NUM_TCP_PCB_LISTEN || defined __DOXYGEN__
+#define MEMP_NUM_TCP_PCB_LISTEN 8
+#endif
+
+/**
+ * MEMP_NUM_TCP_SEG: the number of simultaneously queued TCP segments.
+ * (requires the LWIP_TCP option)
+ */
+#if !defined MEMP_NUM_TCP_SEG || defined __DOXYGEN__
+#define MEMP_NUM_TCP_SEG 16
+#endif
+
+/**
+ * MEMP_NUM_REASSDATA: the number of IP packets simultaneously queued for
+ * reassembly (whole packets, not fragments!)
+ */
+#if !defined MEMP_NUM_REASSDATA || defined __DOXYGEN__
+#define MEMP_NUM_REASSDATA 5
+#endif
+
+/**
+ * MEMP_NUM_FRAG_PBUF: the number of IP fragments simultaneously sent
+ * (fragments, not whole packets!).
+ * This is only used with LWIP_NETIF_TX_SINGLE_PBUF==0 and only has to be > 1
+ * with DMA-enabled MACs where the packet is not yet sent when netif->output
+ * returns.
+ */
+#if !defined MEMP_NUM_FRAG_PBUF || defined __DOXYGEN__
+#define MEMP_NUM_FRAG_PBUF 15
+#endif
+
+/**
+ * MEMP_NUM_ARP_QUEUE: the number of simultaneously queued outgoing
+ * packets (pbufs) that are waiting for an ARP request (to resolve
+ * their destination address) to finish.
+ * (requires the ARP_QUEUEING option)
+ */
+#if !defined MEMP_NUM_ARP_QUEUE || defined __DOXYGEN__
+#define MEMP_NUM_ARP_QUEUE 30
+#endif
+
+/**
+ * MEMP_NUM_IGMP_GROUP: The number of multicast groups whose network interfaces
+ * can be members at the same time (one per netif - allsystems group -, plus one
+ * per netif membership).
+ * (requires the LWIP_IGMP option)
+ */
+#if !defined MEMP_NUM_IGMP_GROUP || defined __DOXYGEN__
+#define MEMP_NUM_IGMP_GROUP 8
+#endif
+
+/**
+ * MEMP_NUM_SYS_TIMEOUT: the number of simultaneously active timeouts.
+ * The default number of timeouts is calculated here for all enabled modules.
+ * The formula expects settings to be either '0' or '1'.
+ */
+#if !defined MEMP_NUM_SYS_TIMEOUT || defined __DOXYGEN__
+#define MEMP_NUM_SYS_TIMEOUT (LWIP_TCP + IP_REASSEMBLY + LWIP_ARP + (2*LWIP_DHCP) + LWIP_AUTOIP + LWIP_IGMP + LWIP_DNS + (PPP_SUPPORT*6*MEMP_NUM_PPP_PCB) + (LWIP_IPV6 ? (1 + LWIP_IPV6_REASS + LWIP_IPV6_MLD) : 0))
+#endif
+
+/**
+ * MEMP_NUM_NETBUF: the number of struct netbufs.
+ * (only needed if you use the sequential API, like api_lib.c)
+ */
+#if !defined MEMP_NUM_NETBUF || defined __DOXYGEN__
+#define MEMP_NUM_NETBUF 2
+#endif
+
+/**
+ * MEMP_NUM_NETCONN: the number of struct netconns.
+ * (only needed if you use the sequential API, like api_lib.c)
+ */
+#if !defined MEMP_NUM_NETCONN || defined __DOXYGEN__
+#define MEMP_NUM_NETCONN 4
+#endif
+
+/**
+ * MEMP_NUM_TCPIP_MSG_API: the number of struct tcpip_msg, which are used
+ * for callback/timeout API communication.
+ * (only needed if you use tcpip.c)
+ */
+#if !defined MEMP_NUM_TCPIP_MSG_API || defined __DOXYGEN__
+#define MEMP_NUM_TCPIP_MSG_API 8
+#endif
+
+/**
+ * MEMP_NUM_TCPIP_MSG_INPKT: the number of struct tcpip_msg, which are used
+ * for incoming packets.
+ * (only needed if you use tcpip.c)
+ */
+#if !defined MEMP_NUM_TCPIP_MSG_INPKT || defined __DOXYGEN__
+#define MEMP_NUM_TCPIP_MSG_INPKT 8
+#endif
+
+/**
+ * MEMP_NUM_NETDB: the number of concurrently running lwip_addrinfo() calls
+ * (before freeing the corresponding memory using lwip_freeaddrinfo()).
+ */
+#if !defined MEMP_NUM_NETDB || defined __DOXYGEN__
+#define MEMP_NUM_NETDB 1
+#endif
+
+/**
+ * MEMP_NUM_LOCALHOSTLIST: the number of host entries in the local host list
+ * if DNS_LOCAL_HOSTLIST_IS_DYNAMIC==1.
+ */
+#if !defined MEMP_NUM_LOCALHOSTLIST || defined __DOXYGEN__
+#define MEMP_NUM_LOCALHOSTLIST 1
+#endif
+
+/**
+ * PBUF_POOL_SIZE: the number of buffers in the pbuf pool.
+ */
+#if !defined PBUF_POOL_SIZE || defined __DOXYGEN__
+#define PBUF_POOL_SIZE 16
+#endif
+
+/** MEMP_NUM_API_MSG: the number of concurrently active calls to various
+ * socket, netconn, and tcpip functions
+ */
+#if !defined MEMP_NUM_API_MSG || defined __DOXYGEN__
+#define MEMP_NUM_API_MSG MEMP_NUM_TCPIP_MSG_API
+#endif
+
+/** MEMP_NUM_DNS_API_MSG: the number of concurrently active calls to netconn_gethostbyname
+ */
+#if !defined MEMP_NUM_DNS_API_MSG || defined __DOXYGEN__
+#define MEMP_NUM_DNS_API_MSG MEMP_NUM_TCPIP_MSG_API
+#endif
+
+/** MEMP_NUM_SOCKET_SETGETSOCKOPT_DATA: the number of concurrently active calls
+ * to getsockopt/setsockopt
+ */
+#if !defined MEMP_NUM_SOCKET_SETGETSOCKOPT_DATA || defined __DOXYGEN__
+#define MEMP_NUM_SOCKET_SETGETSOCKOPT_DATA MEMP_NUM_TCPIP_MSG_API
+#endif
+
+/** MEMP_NUM_NETIFAPI_MSG: the number of concurrently active calls to the
+ * netifapi functions
+ */
+#if !defined MEMP_NUM_NETIFAPI_MSG || defined __DOXYGEN__
+#define MEMP_NUM_NETIFAPI_MSG MEMP_NUM_TCPIP_MSG_API
+#endif
+/**
+ * @}
+ */
+
+/*
+ ---------------------------------
+ ---------- ARP options ----------
+ ---------------------------------
+*/
+/**
+ * @defgroup lwip_opts_arp ARP
+ * @ingroup lwip_opts_ipv4
+ * @{
+ */
+/**
+ * LWIP_ARP==1: Enable ARP functionality.
+ */
+#if !defined LWIP_ARP || defined __DOXYGEN__
+#define LWIP_ARP 1
+#endif
+
+/**
+ * ARP_TABLE_SIZE: Number of active MAC-IP address pairs cached.
+ */
+#if !defined ARP_TABLE_SIZE || defined __DOXYGEN__
+#define ARP_TABLE_SIZE 10
+#endif
+
+/** the time an ARP entry stays valid after its last update,
+ * for ARP_TMR_INTERVAL = 1000, this is
+ * (60 * 5) seconds = 5 minutes.
+ */
+#if !defined ARP_MAXAGE || defined __DOXYGEN__
+#define ARP_MAXAGE 300
+#endif
+
+/**
+ * ARP_QUEUEING==1: Multiple outgoing packets are queued during hardware address
+ * resolution. By default, only the most recent packet is queued per IP address.
+ * This is sufficient for most protocols and mainly reduces TCP connection
+ * startup time. Set this to 1 if you know your application sends more than one
+ * packet in a row to an IP address that is not in the ARP cache.
+ */
+#if !defined ARP_QUEUEING || defined __DOXYGEN__
+#define ARP_QUEUEING 0
+#endif
+
+/** The maximum number of packets which may be queued for each
+ * unresolved address by other network layers. Defaults to 3, 0 means disabled.
+ * Old packets are dropped, new packets are queued.
+ */
+#if !defined ARP_QUEUE_LEN || defined __DOXYGEN__
+#define ARP_QUEUE_LEN 3
+#endif
+
+/**
+ * ETHARP_SUPPORT_VLAN==1: support receiving and sending ethernet packets with
+ * VLAN header. See the description of LWIP_HOOK_VLAN_CHECK and
+ * LWIP_HOOK_VLAN_SET hooks to check/set VLAN headers.
+ * Additionally, you can define ETHARP_VLAN_CHECK to an u16_t VLAN ID to check.
+ * If ETHARP_VLAN_CHECK is defined, only VLAN-traffic for this VLAN is accepted.
+ * If ETHARP_VLAN_CHECK is not defined, all traffic is accepted.
+ * Alternatively, define a function/define ETHARP_VLAN_CHECK_FN(eth_hdr, vlan)
+ * that returns 1 to accept a packet or 0 to drop a packet.
+ */
+#if !defined ETHARP_SUPPORT_VLAN || defined __DOXYGEN__
+#define ETHARP_SUPPORT_VLAN 0
+#endif
+
+/** LWIP_ETHERNET==1: enable ethernet support even though ARP might be disabled
+ */
+#if !defined LWIP_ETHERNET || defined __DOXYGEN__
+#define LWIP_ETHERNET LWIP_ARP
+#endif
+
+/** ETH_PAD_SIZE: number of bytes added before the ethernet header to ensure
+ * alignment of payload after that header. Since the header is 14 bytes long,
+ * without this padding e.g. addresses in the IP header will not be aligned
+ * on a 32-bit boundary, so setting this to 2 can speed up 32-bit-platforms.
+ */
+#if !defined ETH_PAD_SIZE || defined __DOXYGEN__
+#define ETH_PAD_SIZE 0
+#endif
+
+/** ETHARP_SUPPORT_STATIC_ENTRIES==1: enable code to support static ARP table
+ * entries (using etharp_add_static_entry/etharp_remove_static_entry).
+ */
+#if !defined ETHARP_SUPPORT_STATIC_ENTRIES || defined __DOXYGEN__
+#define ETHARP_SUPPORT_STATIC_ENTRIES 0
+#endif
+
+/** ETHARP_TABLE_MATCH_NETIF==1: Match netif for ARP table entries.
+ * If disabled, duplicate IP address on multiple netifs are not supported
+ * (but this should only occur for AutoIP).
+ */
+#if !defined ETHARP_TABLE_MATCH_NETIF || defined __DOXYGEN__
+#define ETHARP_TABLE_MATCH_NETIF 0
+#endif
+/**
+ * @}
+ */
+
+/*
+ --------------------------------
+ ---------- IP options ----------
+ --------------------------------
+*/
+/**
+ * @defgroup lwip_opts_ipv4 IPv4
+ * @ingroup lwip_opts
+ * @{
+ */
+/**
+ * LWIP_IPV4==1: Enable IPv4
+ */
+#if !defined LWIP_IPV4 || defined __DOXYGEN__
+#define LWIP_IPV4 1
+#endif
+
+/**
+ * IP_FORWARD==1: Enables the ability to forward IP packets across network
+ * interfaces. If you are going to run lwIP on a device with only one network
+ * interface, define this to 0.
+ */
+#if !defined IP_FORWARD || defined __DOXYGEN__
+#define IP_FORWARD 0
+#endif
+
+/**
+ * IP_REASSEMBLY==1: Reassemble incoming fragmented IP packets. Note that
+ * this option does not affect outgoing packet sizes, which can be controlled
+ * via IP_FRAG.
+ */
+#if !defined IP_REASSEMBLY || defined __DOXYGEN__
+#define IP_REASSEMBLY 1
+#endif
+
+/**
+ * IP_FRAG==1: Fragment outgoing IP packets if their size exceeds MTU. Note
+ * that this option does not affect incoming packet sizes, which can be
+ * controlled via IP_REASSEMBLY.
+ */
+#if !defined IP_FRAG || defined __DOXYGEN__
+#define IP_FRAG 1
+#endif
+
+#if !LWIP_IPV4
+/* disable IPv4 extensions when IPv4 is disabled */
+#undef IP_FORWARD
+#define IP_FORWARD 0
+#undef IP_REASSEMBLY
+#define IP_REASSEMBLY 0
+#undef IP_FRAG
+#define IP_FRAG 0
+#endif /* !LWIP_IPV4 */
+
+/**
+ * IP_OPTIONS_ALLOWED: Defines the behavior for IP options.
+ * IP_OPTIONS_ALLOWED==0: All packets with IP options are dropped.
+ * IP_OPTIONS_ALLOWED==1: IP options are allowed (but not parsed).
+ */
+#if !defined IP_OPTIONS_ALLOWED || defined __DOXYGEN__
+#define IP_OPTIONS_ALLOWED 1
+#endif
+
+/**
+ * IP_REASS_MAXAGE: Maximum time (in multiples of IP_TMR_INTERVAL - so seconds, normally)
+ * a fragmented IP packet waits for all fragments to arrive. If not all fragments arrived
+ * in this time, the whole packet is discarded.
+ */
+#if !defined IP_REASS_MAXAGE || defined __DOXYGEN__
+#define IP_REASS_MAXAGE 3
+#endif
+
+/**
+ * IP_REASS_MAX_PBUFS: Total maximum amount of pbufs waiting to be reassembled.
+ * Since the received pbufs are enqueued, be sure to configure
+ * PBUF_POOL_SIZE > IP_REASS_MAX_PBUFS so that the stack is still able to receive
+ * packets even if the maximum amount of fragments is enqueued for reassembly!
+ */
+#if !defined IP_REASS_MAX_PBUFS || defined __DOXYGEN__
+#define IP_REASS_MAX_PBUFS 10
+#endif
+
+/**
+ * IP_DEFAULT_TTL: Default value for Time-To-Live used by transport layers.
+ */
+#if !defined IP_DEFAULT_TTL || defined __DOXYGEN__
+#define IP_DEFAULT_TTL 255
+#endif
+
+/**
+ * IP_SOF_BROADCAST=1: Use the SOF_BROADCAST field to enable broadcast
+ * filter per pcb on udp and raw send operations. To enable broadcast filter
+ * on recv operations, you also have to set IP_SOF_BROADCAST_RECV=1.
+ */
+#if !defined IP_SOF_BROADCAST || defined __DOXYGEN__
+#define IP_SOF_BROADCAST 0
+#endif
+
+/**
+ * IP_SOF_BROADCAST_RECV (requires IP_SOF_BROADCAST=1) enable the broadcast
+ * filter on recv operations.
+ */
+#if !defined IP_SOF_BROADCAST_RECV || defined __DOXYGEN__
+#define IP_SOF_BROADCAST_RECV 0
+#endif
+
+/**
+ * IP_FORWARD_ALLOW_TX_ON_RX_NETIF==1: allow ip_forward() to send packets back
+ * out on the netif where it was received. This should only be used for
+ * wireless networks.
+ * ATTENTION: When this is 1, make sure your netif driver correctly marks incoming
+ * link-layer-broadcast/multicast packets as such using the corresponding pbuf flags!
+ */
+#if !defined IP_FORWARD_ALLOW_TX_ON_RX_NETIF || defined __DOXYGEN__
+#define IP_FORWARD_ALLOW_TX_ON_RX_NETIF 0
+#endif
+
+/**
+ * LWIP_RANDOMIZE_INITIAL_LOCAL_PORTS==1: randomize the local port for the first
+ * local TCP/UDP pcb (default==0). This can prevent creating predictable port
+ * numbers after booting a device.
+ */
+#if !defined LWIP_RANDOMIZE_INITIAL_LOCAL_PORTS || defined __DOXYGEN__
+#define LWIP_RANDOMIZE_INITIAL_LOCAL_PORTS 0
+#endif
+/**
+ * @}
+ */
+
+/*
+ ----------------------------------
+ ---------- ICMP options ----------
+ ----------------------------------
+*/
+/**
+ * @defgroup lwip_opts_icmp ICMP
+ * @ingroup lwip_opts_ipv4
+ * @{
+ */
+/**
+ * LWIP_ICMP==1: Enable ICMP module inside the IP stack.
+ * Be careful, disable that make your product non-compliant to RFC1122
+ */
+#if !defined LWIP_ICMP || defined __DOXYGEN__
+#define LWIP_ICMP 1
+#endif
+
+/**
+ * ICMP_TTL: Default value for Time-To-Live used by ICMP packets.
+ */
+#if !defined ICMP_TTL || defined __DOXYGEN__
+#define ICMP_TTL (IP_DEFAULT_TTL)
+#endif
+
+/**
+ * LWIP_BROADCAST_PING==1: respond to broadcast pings (default is unicast only)
+ */
+#if !defined LWIP_BROADCAST_PING || defined __DOXYGEN__
+#define LWIP_BROADCAST_PING 0
+#endif
+
+/**
+ * LWIP_MULTICAST_PING==1: respond to multicast pings (default is unicast only)
+ */
+#if !defined LWIP_MULTICAST_PING || defined __DOXYGEN__
+#define LWIP_MULTICAST_PING 0
+#endif
+/**
+ * @}
+ */
+
+/*
+ ---------------------------------
+ ---------- RAW options ----------
+ ---------------------------------
+*/
+/**
+ * @defgroup lwip_opts_raw RAW
+ * @ingroup lwip_opts_callback
+ * @{
+ */
+/**
+ * LWIP_RAW==1: Enable application layer to hook into the IP layer itself.
+ */
+#if !defined LWIP_RAW || defined __DOXYGEN__
+#define LWIP_RAW 0
+#endif
+
+/**
+ * LWIP_RAW==1: Enable application layer to hook into the IP layer itself.
+ */
+#if !defined RAW_TTL || defined __DOXYGEN__
+#define RAW_TTL (IP_DEFAULT_TTL)
+#endif
+/**
+ * @}
+ */
+
+/*
+ ----------------------------------
+ ---------- DHCP options ----------
+ ----------------------------------
+*/
+/**
+ * @defgroup lwip_opts_dhcp DHCP
+ * @ingroup lwip_opts_ipv4
+ * @{
+ */
+/**
+ * LWIP_DHCP==1: Enable DHCP module.
+ */
+#if !defined LWIP_DHCP || defined __DOXYGEN__
+#define LWIP_DHCP 0
+#endif
+#if !LWIP_IPV4
+/* disable DHCP when IPv4 is disabled */
+#undef LWIP_DHCP
+#define LWIP_DHCP 0
+#endif /* !LWIP_IPV4 */
+
+/**
+ * DHCP_DOES_ARP_CHECK==1: Do an ARP check on the offered address.
+ */
+#if !defined DHCP_DOES_ARP_CHECK || defined __DOXYGEN__
+#define DHCP_DOES_ARP_CHECK ((LWIP_DHCP) && (LWIP_ARP))
+#endif
+
+/**
+ * LWIP_DHCP_CHECK_LINK_UP==1: dhcp_start() only really starts if the netif has
+ * NETIF_FLAG_LINK_UP set in its flags. As this is only an optimization and
+ * netif drivers might not set this flag, the default is off. If enabled,
+ * netif_set_link_up() must be called to continue dhcp starting.
+ */
+#if !defined LWIP_DHCP_CHECK_LINK_UP
+#define LWIP_DHCP_CHECK_LINK_UP 0
+#endif
+
+/**
+ * LWIP_DHCP_BOOTP_FILE==1: Store offered_si_addr and boot_file_name.
+ */
+#if !defined LWIP_DHCP_BOOTP_FILE || defined __DOXYGEN__
+#define LWIP_DHCP_BOOTP_FILE 0
+#endif
+
+/**
+ * LWIP_DHCP_GETS_NTP==1: Request NTP servers with discover/select. For each
+ * response packet, an callback is called, which has to be provided by the port:
+ * void dhcp_set_ntp_servers(u8_t num_ntp_servers, ip_addr_t* ntp_server_addrs);
+*/
+#if !defined LWIP_DHCP_GET_NTP_SRV || defined __DOXYGEN__
+#define LWIP_DHCP_GET_NTP_SRV 0
+#endif
+
+/**
+ * The maximum of NTP servers requested
+ */
+#if !defined LWIP_DHCP_MAX_NTP_SERVERS || defined __DOXYGEN__
+#define LWIP_DHCP_MAX_NTP_SERVERS 1
+#endif
+
+/**
+ * LWIP_DHCP_MAX_DNS_SERVERS > 0: Request DNS servers with discover/select.
+ * DHCP servers received in the response are passed to DNS via @ref dns_setserver()
+ * (up to the maximum limit defined here).
+ */
+#if !defined LWIP_DHCP_MAX_DNS_SERVERS || defined __DOXYGEN__
+#define LWIP_DHCP_MAX_DNS_SERVERS DNS_MAX_SERVERS
+#endif
+/**
+ * @}
+ */
+
+/*
+ ------------------------------------
+ ---------- AUTOIP options ----------
+ ------------------------------------
+*/
+/**
+ * @defgroup lwip_opts_autoip AUTOIP
+ * @ingroup lwip_opts_ipv4
+ * @{
+ */
+/**
+ * LWIP_AUTOIP==1: Enable AUTOIP module.
+ */
+#if !defined LWIP_AUTOIP || defined __DOXYGEN__
+#define LWIP_AUTOIP 0
+#endif
+#if !LWIP_IPV4
+/* disable AUTOIP when IPv4 is disabled */
+#undef LWIP_AUTOIP
+#define LWIP_AUTOIP 0
+#endif /* !LWIP_IPV4 */
+
+/**
+ * LWIP_DHCP_AUTOIP_COOP==1: Allow DHCP and AUTOIP to be both enabled on
+ * the same interface at the same time.
+ */
+#if !defined LWIP_DHCP_AUTOIP_COOP || defined __DOXYGEN__
+#define LWIP_DHCP_AUTOIP_COOP 0
+#endif
+
+/**
+ * LWIP_DHCP_AUTOIP_COOP_TRIES: Set to the number of DHCP DISCOVER probes
+ * that should be sent before falling back on AUTOIP (the DHCP client keeps
+ * running in this case). This can be set as low as 1 to get an AutoIP address
+ * very quickly, but you should be prepared to handle a changing IP address
+ * when DHCP overrides AutoIP.
+ */
+#if !defined LWIP_DHCP_AUTOIP_COOP_TRIES || defined __DOXYGEN__
+#define LWIP_DHCP_AUTOIP_COOP_TRIES 9
+#endif
+/**
+ * @}
+ */
+
+/*
+ ----------------------------------
+ ----- SNMP MIB2 support -----
+ ----------------------------------
+*/
+/**
+ * @defgroup lwip_opts_mib2 SNMP MIB2 callbacks
+ * @ingroup lwip_opts_infrastructure
+ * @{
+ */
+/**
+ * LWIP_MIB2_CALLBACKS==1: Turn on SNMP MIB2 callbacks.
+ * Turn this on to get callbacks needed to implement MIB2.
+ * Usually MIB2_STATS should be enabled, too.
+ */
+#if !defined LWIP_MIB2_CALLBACKS || defined __DOXYGEN__
+#define LWIP_MIB2_CALLBACKS 0
+#endif
+/**
+ * @}
+ */
+
+/*
+ ----------------------------------
+ ----- Multicast/IGMP options -----
+ ----------------------------------
+*/
+/**
+ * @defgroup lwip_opts_igmp IGMP
+ * @ingroup lwip_opts_ipv4
+ * @{
+ */
+/**
+ * LWIP_IGMP==1: Turn on IGMP module.
+ */
+#if !defined LWIP_IGMP || defined __DOXYGEN__
+#define LWIP_IGMP 0
+#endif
+#if !LWIP_IPV4
+#undef LWIP_IGMP
+#define LWIP_IGMP 0
+#endif
+
+/**
+ * LWIP_MULTICAST_TX_OPTIONS==1: Enable multicast TX support like the socket options
+ * IP_MULTICAST_TTL/IP_MULTICAST_IF/IP_MULTICAST_LOOP
+ */
+#if !defined LWIP_MULTICAST_TX_OPTIONS || defined __DOXYGEN__
+#define LWIP_MULTICAST_TX_OPTIONS (LWIP_IGMP && LWIP_UDP)
+#endif
+/**
+ * @}
+ */
+
+/*
+ ----------------------------------
+ ---------- DNS options -----------
+ ----------------------------------
+*/
+/**
+ * @defgroup lwip_opts_dns DNS
+ * @ingroup lwip_opts_callback
+ * @{
+ */
+/**
+ * LWIP_DNS==1: Turn on DNS module. UDP must be available for DNS
+ * transport.
+ */
+#if !defined LWIP_DNS || defined __DOXYGEN__
+#define LWIP_DNS 0
+#endif
+
+/** DNS maximum number of entries to maintain locally. */
+#if !defined DNS_TABLE_SIZE || defined __DOXYGEN__
+#define DNS_TABLE_SIZE 4
+#endif
+
+/** DNS maximum host name length supported in the name table. */
+#if !defined DNS_MAX_NAME_LENGTH || defined __DOXYGEN__
+#define DNS_MAX_NAME_LENGTH 256
+#endif
+
+/** The maximum of DNS servers
+ * The first server can be initialized automatically by defining
+ * DNS_SERVER_ADDRESS(ipaddr), where 'ipaddr' is an 'ip_addr_t*'
+ */
+#if !defined DNS_MAX_SERVERS || defined __DOXYGEN__
+#define DNS_MAX_SERVERS 2
+#endif
+
+/** DNS do a name checking between the query and the response. */
+#if !defined DNS_DOES_NAME_CHECK || defined __DOXYGEN__
+#define DNS_DOES_NAME_CHECK 1
+#endif
+
+/** LWIP_DNS_SECURE: controls the security level of the DNS implementation
+ * Use all DNS security features by default.
+ * This is overridable but should only be needed by very small targets
+ * or when using against non standard DNS servers. */
+#if !defined LWIP_DNS_SECURE || defined __DOXYGEN__
+#define LWIP_DNS_SECURE (LWIP_DNS_SECURE_RAND_XID | LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING | LWIP_DNS_SECURE_RAND_SRC_PORT)
+#endif
+
+/* A list of DNS security features follows */
+#define LWIP_DNS_SECURE_RAND_XID 1
+#define LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING 2
+#define LWIP_DNS_SECURE_RAND_SRC_PORT 4
+
+/** DNS_LOCAL_HOSTLIST: Implements a local host-to-address list. If enabled, you have to define an initializer:
+ * \#define DNS_LOCAL_HOSTLIST_INIT {DNS_LOCAL_HOSTLIST_ELEM("host_ip4", IPADDR4_INIT_BYTES(1,2,3,4)), \
+ * DNS_LOCAL_HOSTLIST_ELEM("host_ip6", IPADDR6_INIT_HOST(123, 234, 345, 456)}
+ *
+ * Instead, you can also use an external function:
+ * \#define DNS_LOOKUP_LOCAL_EXTERN(x) extern err_t my_lookup_function(const char *name, ip_addr_t *addr, u8_t dns_addrtype)
+ * that looks up the IP address and returns ERR_OK if found (LWIP_DNS_ADDRTYPE_xxx is passed in dns_addrtype).
+ */
+#if !defined DNS_LOCAL_HOSTLIST || defined __DOXYGEN__
+#define DNS_LOCAL_HOSTLIST 0
+#endif /* DNS_LOCAL_HOSTLIST */
+
+/** If this is turned on, the local host-list can be dynamically changed
+ * at runtime. */
+#if !defined DNS_LOCAL_HOSTLIST_IS_DYNAMIC || defined __DOXYGEN__
+#define DNS_LOCAL_HOSTLIST_IS_DYNAMIC 0
+#endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
+
+/** Set this to 1 to enable querying ".local" names via mDNS
+ * using a One-Shot Multicast DNS Query */
+#if !defined LWIP_DNS_SUPPORT_MDNS_QUERIES || defined __DOXYGEN__
+#define LWIP_DNS_SUPPORT_MDNS_QUERIES 0
+#endif
+/**
+ * @}
+ */
+
+/*
+ ---------------------------------
+ ---------- UDP options ----------
+ ---------------------------------
+*/
+/**
+ * @defgroup lwip_opts_udp UDP
+ * @ingroup lwip_opts_callback
+ * @{
+ */
+/**
+ * LWIP_UDP==1: Turn on UDP.
+ */
+#if !defined LWIP_UDP || defined __DOXYGEN__
+#define LWIP_UDP 1
+#endif
+
+/**
+ * LWIP_UDPLITE==1: Turn on UDP-Lite. (Requires LWIP_UDP)
+ */
+#if !defined LWIP_UDPLITE || defined __DOXYGEN__
+#define LWIP_UDPLITE 0
+#endif
+
+/**
+ * UDP_TTL: Default Time-To-Live value.
+ */
+#if !defined UDP_TTL || defined __DOXYGEN__
+#define UDP_TTL (IP_DEFAULT_TTL)
+#endif
+
+/**
+ * LWIP_NETBUF_RECVINFO==1: append destination addr and port to every netbuf.
+ */
+#if !defined LWIP_NETBUF_RECVINFO || defined __DOXYGEN__
+#define LWIP_NETBUF_RECVINFO 0
+#endif
+/**
+ * @}
+ */
+
+/*
+ ---------------------------------
+ ---------- TCP options ----------
+ ---------------------------------
+*/
+/**
+ * @defgroup lwip_opts_tcp TCP
+ * @ingroup lwip_opts_callback
+ * @{
+ */
+/**
+ * LWIP_TCP==1: Turn on TCP.
+ */
+#if !defined LWIP_TCP || defined __DOXYGEN__
+#define LWIP_TCP 1
+#endif
+
+/**
+ * TCP_TTL: Default Time-To-Live value.
+ */
+#if !defined TCP_TTL || defined __DOXYGEN__
+#define TCP_TTL (IP_DEFAULT_TTL)
+#endif
+
+/**
+ * TCP_WND: The size of a TCP window. This must be at least
+ * (2 * TCP_MSS) for things to work well.
+ * ATTENTION: when using TCP_RCV_SCALE, TCP_WND is the total size
+ * with scaling applied. Maximum window value in the TCP header
+ * will be TCP_WND >> TCP_RCV_SCALE
+ */
+#if !defined TCP_WND || defined __DOXYGEN__
+#define TCP_WND (4 * TCP_MSS)
+#endif
+
+/**
+ * TCP_MAXRTX: Maximum number of retransmissions of data segments.
+ */
+#if !defined TCP_MAXRTX || defined __DOXYGEN__
+#define TCP_MAXRTX 12
+#endif
+
+/**
+ * TCP_SYNMAXRTX: Maximum number of retransmissions of SYN segments.
+ */
+#if !defined TCP_SYNMAXRTX || defined __DOXYGEN__
+#define TCP_SYNMAXRTX 6
+#endif
+
+/**
+ * TCP_QUEUE_OOSEQ==1: TCP will queue segments that arrive out of order.
+ * Define to 0 if your device is low on memory.
+ */
+#if !defined TCP_QUEUE_OOSEQ || defined __DOXYGEN__
+#define TCP_QUEUE_OOSEQ (LWIP_TCP)
+#endif
+
+/**
+ * TCP_MSS: TCP Maximum segment size. (default is 536, a conservative default,
+ * you might want to increase this.)
+ * For the receive side, this MSS is advertised to the remote side
+ * when opening a connection. For the transmit size, this MSS sets
+ * an upper limit on the MSS advertised by the remote host.
+ */
+#if !defined TCP_MSS || defined __DOXYGEN__
+#define TCP_MSS 536
+#endif
+
+/**
+ * TCP_CALCULATE_EFF_SEND_MSS: "The maximum size of a segment that TCP really
+ * sends, the 'effective send MSS,' MUST be the smaller of the send MSS (which
+ * reflects the available reassembly buffer size at the remote host) and the
+ * largest size permitted by the IP layer" (RFC 1122)
+ * Setting this to 1 enables code that checks TCP_MSS against the MTU of the
+ * netif used for a connection and limits the MSS if it would be too big otherwise.
+ */
+#if !defined TCP_CALCULATE_EFF_SEND_MSS || defined __DOXYGEN__
+#define TCP_CALCULATE_EFF_SEND_MSS 1
+#endif
+
+/**
+ * TCP_SND_BUF: TCP sender buffer space (bytes).
+ * To achieve good performance, this should be at least 2 * TCP_MSS.
+ */
+#if !defined TCP_SND_BUF || defined __DOXYGEN__
+#define TCP_SND_BUF (2 * TCP_MSS)
+#endif
+
+/**
+ * TCP_SND_QUEUELEN: TCP sender buffer space (pbufs). This must be at least
+ * as much as (2 * TCP_SND_BUF/TCP_MSS) for things to work.
+ */
+#if !defined TCP_SND_QUEUELEN || defined __DOXYGEN__
+#define TCP_SND_QUEUELEN ((4 * (TCP_SND_BUF) + (TCP_MSS - 1))/(TCP_MSS))
+#endif
+
+/**
+ * TCP_SNDLOWAT: TCP writable space (bytes). This must be less than
+ * TCP_SND_BUF. It is the amount of space which must be available in the
+ * TCP snd_buf for select to return writable (combined with TCP_SNDQUEUELOWAT).
+ */
+#if !defined TCP_SNDLOWAT || defined __DOXYGEN__
+#define TCP_SNDLOWAT LWIP_MIN(LWIP_MAX(((TCP_SND_BUF)/2), (2 * TCP_MSS) + 1), (TCP_SND_BUF) - 1)
+#endif
+
+/**
+ * TCP_SNDQUEUELOWAT: TCP writable bufs (pbuf count). This must be less
+ * than TCP_SND_QUEUELEN. If the number of pbufs queued on a pcb drops below
+ * this number, select returns writable (combined with TCP_SNDLOWAT).
+ */
+#if !defined TCP_SNDQUEUELOWAT || defined __DOXYGEN__
+#define TCP_SNDQUEUELOWAT LWIP_MAX(((TCP_SND_QUEUELEN)/2), 5)
+#endif
+
+/**
+ * TCP_OOSEQ_MAX_BYTES: The maximum number of bytes queued on ooseq per pcb.
+ * Default is 0 (no limit). Only valid for TCP_QUEUE_OOSEQ==1.
+ */
+#if !defined TCP_OOSEQ_MAX_BYTES || defined __DOXYGEN__
+#define TCP_OOSEQ_MAX_BYTES 0
+#endif
+
+/**
+ * TCP_OOSEQ_MAX_PBUFS: The maximum number of pbufs queued on ooseq per pcb.
+ * Default is 0 (no limit). Only valid for TCP_QUEUE_OOSEQ==1.
+ */
+#if !defined TCP_OOSEQ_MAX_PBUFS || defined __DOXYGEN__
+#define TCP_OOSEQ_MAX_PBUFS 0
+#endif
+
+/**
+ * TCP_LISTEN_BACKLOG: Enable the backlog option for tcp listen pcb.
+ */
+#if !defined TCP_LISTEN_BACKLOG || defined __DOXYGEN__
+#define TCP_LISTEN_BACKLOG 0
+#endif
+
+/**
+ * The maximum allowed backlog for TCP listen netconns.
+ * This backlog is used unless another is explicitly specified.
+ * 0xff is the maximum (u8_t).
+ */
+#if !defined TCP_DEFAULT_LISTEN_BACKLOG || defined __DOXYGEN__
+#define TCP_DEFAULT_LISTEN_BACKLOG 0xff
+#endif
+
+/**
+ * TCP_OVERSIZE: The maximum number of bytes that tcp_write may
+ * allocate ahead of time in an attempt to create shorter pbuf chains
+ * for transmission. The meaningful range is 0 to TCP_MSS. Some
+ * suggested values are:
+ *
+ * 0: Disable oversized allocation. Each tcp_write() allocates a new
+ pbuf (old behaviour).
+ * 1: Allocate size-aligned pbufs with minimal excess. Use this if your
+ * scatter-gather DMA requires aligned fragments.
+ * 128: Limit the pbuf/memory overhead to 20%.
+ * TCP_MSS: Try to create unfragmented TCP packets.
+ * TCP_MSS/4: Try to create 4 fragments or less per TCP packet.
+ */
+#if !defined TCP_OVERSIZE || defined __DOXYGEN__
+#define TCP_OVERSIZE TCP_MSS
+#endif
+
+/**
+ * LWIP_TCP_TIMESTAMPS==1: support the TCP timestamp option.
+ * The timestamp option is currently only used to help remote hosts, it is not
+ * really used locally. Therefore, it is only enabled when a TS option is
+ * received in the initial SYN packet from a remote host.
+ */
+#if !defined LWIP_TCP_TIMESTAMPS || defined __DOXYGEN__
+#define LWIP_TCP_TIMESTAMPS 0
+#endif
+
+/**
+ * TCP_WND_UPDATE_THRESHOLD: difference in window to trigger an
+ * explicit window update
+ */
+#if !defined TCP_WND_UPDATE_THRESHOLD || defined __DOXYGEN__
+#define TCP_WND_UPDATE_THRESHOLD LWIP_MIN((TCP_WND / 4), (TCP_MSS * 4))
+#endif
+
+/**
+ * LWIP_EVENT_API and LWIP_CALLBACK_API: Only one of these should be set to 1.
+ * LWIP_EVENT_API==1: The user defines lwip_tcp_event() to receive all
+ * events (accept, sent, etc) that happen in the system.
+ * LWIP_CALLBACK_API==1: The PCB callback function is called directly
+ * for the event. This is the default.
+ */
+#if !defined(LWIP_EVENT_API) && !defined(LWIP_CALLBACK_API) || defined __DOXYGEN__
+#define LWIP_EVENT_API 0
+#define LWIP_CALLBACK_API 1
+#else
+#ifndef LWIP_EVENT_API
+#define LWIP_EVENT_API 0
+#endif
+#ifndef LWIP_CALLBACK_API
+#define LWIP_CALLBACK_API 0
+#endif
+#endif
+
+/**
+ * LWIP_WND_SCALE and TCP_RCV_SCALE:
+ * Set LWIP_WND_SCALE to 1 to enable window scaling.
+ * Set TCP_RCV_SCALE to the desired scaling factor (shift count in the
+ * range of [0..14]).
+ * When LWIP_WND_SCALE is enabled but TCP_RCV_SCALE is 0, we can use a large
+ * send window while having a small receive window only.
+ */
+#if !defined LWIP_WND_SCALE || defined __DOXYGEN__
+#define LWIP_WND_SCALE 0
+#define TCP_RCV_SCALE 0
+#endif
+/**
+ * @}
+ */
+
+/*
+ ----------------------------------
+ ---------- Pbuf options ----------
+ ----------------------------------
+*/
+/**
+ * @defgroup lwip_opts_pbuf PBUF
+ * @ingroup lwip_opts
+ * @{
+ */
+/**
+ * PBUF_LINK_HLEN: the number of bytes that should be allocated for a
+ * link level header. The default is 14, the standard value for
+ * Ethernet.
+ */
+#if !defined PBUF_LINK_HLEN || defined __DOXYGEN__
+#if defined LWIP_HOOK_VLAN_SET && !defined __DOXYGEN__
+#define PBUF_LINK_HLEN (18 + ETH_PAD_SIZE)
+#else /* LWIP_HOOK_VLAN_SET */
+#define PBUF_LINK_HLEN (14 + ETH_PAD_SIZE)
+#endif /* LWIP_HOOK_VLAN_SET */
+#endif
+
+/**
+ * PBUF_LINK_ENCAPSULATION_HLEN: the number of bytes that should be allocated
+ * for an additional encapsulation header before ethernet headers (e.g. 802.11)
+ */
+#if !defined PBUF_LINK_ENCAPSULATION_HLEN || defined __DOXYGEN__
+#define PBUF_LINK_ENCAPSULATION_HLEN 0u
+#endif
+
+/**
+ * PBUF_POOL_BUFSIZE: the size of each pbuf in the pbuf pool. The default is
+ * designed to accommodate single full size TCP frame in one pbuf, including
+ * TCP_MSS, IP header, and link header.
+ */
+#if !defined PBUF_POOL_BUFSIZE || defined __DOXYGEN__
+#define PBUF_POOL_BUFSIZE LWIP_MEM_ALIGN_SIZE(TCP_MSS+40+PBUF_LINK_ENCAPSULATION_HLEN+PBUF_LINK_HLEN)
+#endif
+/**
+ * @}
+ */
+
+/*
+ ------------------------------------------------
+ ---------- Network Interfaces options ----------
+ ------------------------------------------------
+*/
+/**
+ * @defgroup lwip_opts_netif NETIF
+ * @ingroup lwip_opts
+ * @{
+ */
+/**
+ * LWIP_NETIF_HOSTNAME==1: use DHCP_OPTION_HOSTNAME with netif's hostname
+ * field.
+ */
+#if !defined LWIP_NETIF_HOSTNAME || defined __DOXYGEN__
+#define LWIP_NETIF_HOSTNAME 0
+#endif
+
+/**
+ * LWIP_NETIF_API==1: Support netif api (in netifapi.c)
+ */
+#if !defined LWIP_NETIF_API || defined __DOXYGEN__
+#define LWIP_NETIF_API 0
+#endif
+
+/**
+ * LWIP_NETIF_STATUS_CALLBACK==1: Support a callback function whenever an interface
+ * changes its up/down status (i.e., due to DHCP IP acquisition)
+ */
+#if !defined LWIP_NETIF_STATUS_CALLBACK || defined __DOXYGEN__
+#define LWIP_NETIF_STATUS_CALLBACK 0
+#endif
+
+/**
+ * LWIP_NETIF_LINK_CALLBACK==1: Support a callback function from an interface
+ * whenever the link changes (i.e., link down)
+ */
+#if !defined LWIP_NETIF_LINK_CALLBACK || defined __DOXYGEN__
+#define LWIP_NETIF_LINK_CALLBACK 0
+#endif
+
+/**
+ * LWIP_NETIF_REMOVE_CALLBACK==1: Support a callback function that is called
+ * when a netif has been removed
+ */
+#if !defined LWIP_NETIF_REMOVE_CALLBACK || defined __DOXYGEN__
+#define LWIP_NETIF_REMOVE_CALLBACK 0
+#endif
+
+/**
+ * LWIP_NETIF_HWADDRHINT==1: Cache link-layer-address hints (e.g. table
+ * indices) in struct netif. TCP and UDP can make use of this to prevent
+ * scanning the ARP table for every sent packet. While this is faster for big
+ * ARP tables or many concurrent connections, it might be counterproductive
+ * if you have a tiny ARP table or if there never are concurrent connections.
+ */
+#if !defined LWIP_NETIF_HWADDRHINT || defined __DOXYGEN__
+#define LWIP_NETIF_HWADDRHINT 0
+#endif
+
+/**
+ * LWIP_NETIF_TX_SINGLE_PBUF: if this is set to 1, lwIP tries to put all data
+ * to be sent into one single pbuf. This is for compatibility with DMA-enabled
+ * MACs that do not support scatter-gather.
+ * Beware that this might involve CPU-memcpy before transmitting that would not
+ * be needed without this flag! Use this only if you need to!
+ *
+ * @todo: TCP and IP-frag do not work with this, yet:
+ */
+#if !defined LWIP_NETIF_TX_SINGLE_PBUF || defined __DOXYGEN__
+#define LWIP_NETIF_TX_SINGLE_PBUF 0
+#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
+
+/**
+ * LWIP_NUM_NETIF_CLIENT_DATA: Number of clients that may store
+ * data in client_data member array of struct netif.
+ */
+#if !defined LWIP_NUM_NETIF_CLIENT_DATA || defined __DOXYGEN__
+#define LWIP_NUM_NETIF_CLIENT_DATA 0
+#endif
+/**
+ * @}
+ */
+
+/*
+ ------------------------------------
+ ---------- LOOPIF options ----------
+ ------------------------------------
+*/
+/**
+ * @defgroup lwip_opts_loop Loopback interface
+ * @ingroup lwip_opts_netif
+ * @{
+ */
+/**
+ * LWIP_HAVE_LOOPIF==1: Support loop interface (127.0.0.1).
+ * This is only needed when no real netifs are available. If at least one other
+ * netif is available, loopback traffic uses this netif.
+ */
+#if !defined LWIP_HAVE_LOOPIF || defined __DOXYGEN__
+#define LWIP_HAVE_LOOPIF LWIP_NETIF_LOOPBACK
+#endif
+
+/**
+ * LWIP_LOOPIF_MULTICAST==1: Support multicast/IGMP on loop interface (127.0.0.1).
+ */
+#if !defined LWIP_LOOPIF_MULTICAST || defined __DOXYGEN__
+#define LWIP_LOOPIF_MULTICAST 0
+#endif
+
+/**
+ * LWIP_NETIF_LOOPBACK==1: Support sending packets with a destination IP
+ * address equal to the netif IP address, looping them back up the stack.
+ */
+#if !defined LWIP_NETIF_LOOPBACK || defined __DOXYGEN__
+#define LWIP_NETIF_LOOPBACK 0
+#endif
+
+/**
+ * LWIP_LOOPBACK_MAX_PBUFS: Maximum number of pbufs on queue for loopback
+ * sending for each netif (0 = disabled)
+ */
+#if !defined LWIP_LOOPBACK_MAX_PBUFS || defined __DOXYGEN__
+#define LWIP_LOOPBACK_MAX_PBUFS 0
+#endif
+
+/**
+ * LWIP_NETIF_LOOPBACK_MULTITHREADING: Indicates whether threading is enabled in
+ * the system, as netifs must change how they behave depending on this setting
+ * for the LWIP_NETIF_LOOPBACK option to work.
+ * Setting this is needed to avoid reentering non-reentrant functions like
+ * tcp_input().
+ * LWIP_NETIF_LOOPBACK_MULTITHREADING==1: Indicates that the user is using a
+ * multithreaded environment like tcpip.c. In this case, netif->input()
+ * is called directly.
+ * LWIP_NETIF_LOOPBACK_MULTITHREADING==0: Indicates a polling (or NO_SYS) setup.
+ * The packets are put on a list and netif_poll() must be called in
+ * the main application loop.
+ */
+#if !defined LWIP_NETIF_LOOPBACK_MULTITHREADING || defined __DOXYGEN__
+#define LWIP_NETIF_LOOPBACK_MULTITHREADING (!NO_SYS)
+#endif
+/**
+ * @}
+ */
+
+/*
+ ------------------------------------
+ ---------- Thread options ----------
+ ------------------------------------
+*/
+/**
+ * @defgroup lwip_opts_thread Threading
+ * @ingroup lwip_opts_infrastructure
+ * @{
+ */
+/**
+ * TCPIP_THREAD_NAME: The name assigned to the main tcpip thread.
+ */
+#if !defined TCPIP_THREAD_NAME || defined __DOXYGEN__
+#define TCPIP_THREAD_NAME "tcpip_thread"
+#endif
+
+/**
+ * TCPIP_THREAD_STACKSIZE: The stack size used by the main tcpip thread.
+ * The stack size value itself is platform-dependent, but is passed to
+ * sys_thread_new() when the thread is created.
+ */
+#if !defined TCPIP_THREAD_STACKSIZE || defined __DOXYGEN__
+#define TCPIP_THREAD_STACKSIZE 0
+#endif
+
+/**
+ * TCPIP_THREAD_PRIO: The priority assigned to the main tcpip thread.
+ * The priority value itself is platform-dependent, but is passed to
+ * sys_thread_new() when the thread is created.
+ */
+#if !defined TCPIP_THREAD_PRIO || defined __DOXYGEN__
+#define TCPIP_THREAD_PRIO 1
+#endif
+
+/**
+ * TCPIP_MBOX_SIZE: The mailbox size for the tcpip thread messages
+ * The queue size value itself is platform-dependent, but is passed to
+ * sys_mbox_new() when tcpip_init is called.
+ */
+#if !defined TCPIP_MBOX_SIZE || defined __DOXYGEN__
+#define TCPIP_MBOX_SIZE 0
+#endif
+
+/**
+ * Define this to something that triggers a watchdog. This is called from
+ * tcpip_thread after processing a message.
+ */
+#if !defined LWIP_TCPIP_THREAD_ALIVE || defined __DOXYGEN__
+#define LWIP_TCPIP_THREAD_ALIVE()
+#endif
+
+/**
+ * SLIPIF_THREAD_NAME: The name assigned to the slipif_loop thread.
+ */
+#if !defined SLIPIF_THREAD_NAME || defined __DOXYGEN__
+#define SLIPIF_THREAD_NAME "slipif_loop"
+#endif
+
+/**
+ * SLIP_THREAD_STACKSIZE: The stack size used by the slipif_loop thread.
+ * The stack size value itself is platform-dependent, but is passed to
+ * sys_thread_new() when the thread is created.
+ */
+#if !defined SLIPIF_THREAD_STACKSIZE || defined __DOXYGEN__
+#define SLIPIF_THREAD_STACKSIZE 0
+#endif
+
+/**
+ * SLIPIF_THREAD_PRIO: The priority assigned to the slipif_loop thread.
+ * The priority value itself is platform-dependent, but is passed to
+ * sys_thread_new() when the thread is created.
+ */
+#if !defined SLIPIF_THREAD_PRIO || defined __DOXYGEN__
+#define SLIPIF_THREAD_PRIO 1
+#endif
+
+/**
+ * DEFAULT_THREAD_NAME: The name assigned to any other lwIP thread.
+ */
+#if !defined DEFAULT_THREAD_NAME || defined __DOXYGEN__
+#define DEFAULT_THREAD_NAME "lwIP"
+#endif
+
+/**
+ * DEFAULT_THREAD_STACKSIZE: The stack size used by any other lwIP thread.
+ * The stack size value itself is platform-dependent, but is passed to
+ * sys_thread_new() when the thread is created.
+ */
+#if !defined DEFAULT_THREAD_STACKSIZE || defined __DOXYGEN__
+#define DEFAULT_THREAD_STACKSIZE 0
+#endif
+
+/**
+ * DEFAULT_THREAD_PRIO: The priority assigned to any other lwIP thread.
+ * The priority value itself is platform-dependent, but is passed to
+ * sys_thread_new() when the thread is created.
+ */
+#if !defined DEFAULT_THREAD_PRIO || defined __DOXYGEN__
+#define DEFAULT_THREAD_PRIO 1
+#endif
+
+/**
+ * DEFAULT_RAW_RECVMBOX_SIZE: The mailbox size for the incoming packets on a
+ * NETCONN_RAW. The queue size value itself is platform-dependent, but is passed
+ * to sys_mbox_new() when the recvmbox is created.
+ */
+#if !defined DEFAULT_RAW_RECVMBOX_SIZE || defined __DOXYGEN__
+#define DEFAULT_RAW_RECVMBOX_SIZE 0
+#endif
+
+/**
+ * DEFAULT_UDP_RECVMBOX_SIZE: The mailbox size for the incoming packets on a
+ * NETCONN_UDP. The queue size value itself is platform-dependent, but is passed
+ * to sys_mbox_new() when the recvmbox is created.
+ */
+#if !defined DEFAULT_UDP_RECVMBOX_SIZE || defined __DOXYGEN__
+#define DEFAULT_UDP_RECVMBOX_SIZE 0
+#endif
+
+/**
+ * DEFAULT_TCP_RECVMBOX_SIZE: The mailbox size for the incoming packets on a
+ * NETCONN_TCP. The queue size value itself is platform-dependent, but is passed
+ * to sys_mbox_new() when the recvmbox is created.
+ */
+#if !defined DEFAULT_TCP_RECVMBOX_SIZE || defined __DOXYGEN__
+#define DEFAULT_TCP_RECVMBOX_SIZE 0
+#endif
+
+/**
+ * DEFAULT_ACCEPTMBOX_SIZE: The mailbox size for the incoming connections.
+ * The queue size value itself is platform-dependent, but is passed to
+ * sys_mbox_new() when the acceptmbox is created.
+ */
+#if !defined DEFAULT_ACCEPTMBOX_SIZE || defined __DOXYGEN__
+#define DEFAULT_ACCEPTMBOX_SIZE 0
+#endif
+/**
+ * @}
+ */
+
+/*
+ ----------------------------------------------
+ ---------- Sequential layer options ----------
+ ----------------------------------------------
+*/
+/**
+ * @defgroup lwip_opts_netconn Netconn
+ * @ingroup lwip_opts_threadsafe_apis
+ * @{
+ */
+/**
+ * LWIP_NETCONN==1: Enable Netconn API (require to use api_lib.c)
+ */
+#if !defined LWIP_NETCONN || defined __DOXYGEN__
+#define LWIP_NETCONN 1
+#endif
+
+/** LWIP_TCPIP_TIMEOUT==1: Enable tcpip_timeout/tcpip_untimeout to create
+ * timers running in tcpip_thread from another thread.
+ */
+#if !defined LWIP_TCPIP_TIMEOUT || defined __DOXYGEN__
+#define LWIP_TCPIP_TIMEOUT 0
+#endif
+
+/** LWIP_NETCONN_SEM_PER_THREAD==1: Use one (thread-local) semaphore per
+ * thread calling socket/netconn functions instead of allocating one
+ * semaphore per netconn (and per select etc.)
+ * ATTENTION: a thread-local semaphore for API calls is needed:
+ * - LWIP_NETCONN_THREAD_SEM_GET() returning a sys_sem_t*
+ * - LWIP_NETCONN_THREAD_SEM_ALLOC() creating the semaphore
+ * - LWIP_NETCONN_THREAD_SEM_FREE() freeing the semaphore
+ * The latter 2 can be invoked up by calling netconn_thread_init()/netconn_thread_cleanup().
+ * Ports may call these for threads created with sys_thread_new().
+ */
+#if !defined LWIP_NETCONN_SEM_PER_THREAD || defined __DOXYGEN__
+#define LWIP_NETCONN_SEM_PER_THREAD 0
+#endif
+
+/** LWIP_NETCONN_FULLDUPLEX==1: Enable code that allows reading from one thread,
+ * writing from a 2nd thread and closing from a 3rd thread at the same time.
+ * ATTENTION: This is currently really alpha! Some requirements:
+ * - LWIP_NETCONN_SEM_PER_THREAD==1 is required to use one socket/netconn from
+ * multiple threads at once
+ * - sys_mbox_free() has to unblock receive tasks waiting on recvmbox/acceptmbox
+ * and prevent a task pending on this during/after deletion
+ */
+#if !defined LWIP_NETCONN_FULLDUPLEX || defined __DOXYGEN__
+#define LWIP_NETCONN_FULLDUPLEX 0
+#endif
+/**
+ * @}
+ */
+
+/*
+ ------------------------------------
+ ---------- Socket options ----------
+ ------------------------------------
+*/
+/**
+ * @defgroup lwip_opts_socket Sockets
+ * @ingroup lwip_opts_threadsafe_apis
+ * @{
+ */
+/**
+ * LWIP_SOCKET==1: Enable Socket API (require to use sockets.c)
+ */
+#if !defined LWIP_SOCKET || defined __DOXYGEN__
+#define LWIP_SOCKET 1
+#endif
+
+/* LWIP_SOCKET_SET_ERRNO==1: Set errno when socket functions cannot complete
+ * successfully, as required by POSIX. Default is POSIX-compliant.
+ */
+#if !defined LWIP_SOCKET_SET_ERRNO || defined __DOXYGEN__
+#define LWIP_SOCKET_SET_ERRNO 1
+#endif
+
+/**
+ * LWIP_COMPAT_SOCKETS==1: Enable BSD-style sockets functions names through defines.
+ * LWIP_COMPAT_SOCKETS==2: Same as ==1 but correctly named functions are created.
+ * While this helps code completion, it might conflict with existing libraries.
+ * (only used if you use sockets.c)
+ */
+#if !defined LWIP_COMPAT_SOCKETS || defined __DOXYGEN__
+#define LWIP_COMPAT_SOCKETS 1
+#endif
+
+/**
+ * LWIP_POSIX_SOCKETS_IO_NAMES==1: Enable POSIX-style sockets functions names.
+ * Disable this option if you use a POSIX operating system that uses the same
+ * names (read, write & close). (only used if you use sockets.c)
+ */
+#if !defined LWIP_POSIX_SOCKETS_IO_NAMES || defined __DOXYGEN__
+#define LWIP_POSIX_SOCKETS_IO_NAMES 1
+#endif
+
+/**
+ * LWIP_SOCKET_OFFSET==n: Increases the file descriptor number created by LwIP with n.
+ * This can be useful when there are multiple APIs which create file descriptors.
+ * When they all start with a different offset and you won't make them overlap you can
+ * re implement read/write/close/ioctl/fnctl to send the requested action to the right
+ * library (sharing select will need more work though).
+ */
+#if !defined LWIP_SOCKET_OFFSET || defined __DOXYGEN__
+#define LWIP_SOCKET_OFFSET 0
+#endif
+
+/**
+ * LWIP_TCP_KEEPALIVE==1: Enable TCP_KEEPIDLE, TCP_KEEPINTVL and TCP_KEEPCNT
+ * options processing. Note that TCP_KEEPIDLE and TCP_KEEPINTVL have to be set
+ * in seconds. (does not require sockets.c, and will affect tcp.c)
+ */
+#if !defined LWIP_TCP_KEEPALIVE || defined __DOXYGEN__
+#define LWIP_TCP_KEEPALIVE 0
+#endif
+
+/**
+ * LWIP_SO_SNDTIMEO==1: Enable send timeout for sockets/netconns and
+ * SO_SNDTIMEO processing.
+ */
+#if !defined LWIP_SO_SNDTIMEO || defined __DOXYGEN__
+#define LWIP_SO_SNDTIMEO 0
+#endif
+
+/**
+ * LWIP_SO_RCVTIMEO==1: Enable receive timeout for sockets/netconns and
+ * SO_RCVTIMEO processing.
+ */
+#if !defined LWIP_SO_RCVTIMEO || defined __DOXYGEN__
+#define LWIP_SO_RCVTIMEO 0
+#endif
+
+/**
+ * LWIP_SO_SNDRCVTIMEO_NONSTANDARD==1: SO_RCVTIMEO/SO_SNDTIMEO take an int
+ * (milliseconds, much like winsock does) instead of a struct timeval (default).
+ */
+#if !defined LWIP_SO_SNDRCVTIMEO_NONSTANDARD || defined __DOXYGEN__
+#define LWIP_SO_SNDRCVTIMEO_NONSTANDARD 0
+#endif
+
+/**
+ * LWIP_SO_RCVBUF==1: Enable SO_RCVBUF processing.
+ */
+#if !defined LWIP_SO_RCVBUF || defined __DOXYGEN__
+#define LWIP_SO_RCVBUF 0
+#endif
+
+/**
+ * LWIP_SO_LINGER==1: Enable SO_LINGER processing.
+ */
+#if !defined LWIP_SO_LINGER || defined __DOXYGEN__
+#define LWIP_SO_LINGER 0
+#endif
+
+/**
+ * If LWIP_SO_RCVBUF is used, this is the default value for recv_bufsize.
+ */
+#if !defined RECV_BUFSIZE_DEFAULT || defined __DOXYGEN__
+#define RECV_BUFSIZE_DEFAULT INT_MAX
+#endif
+
+/**
+ * By default, TCP socket/netconn close waits 20 seconds max to send the FIN
+ */
+#if !defined LWIP_TCP_CLOSE_TIMEOUT_MS_DEFAULT || defined __DOXYGEN__
+#define LWIP_TCP_CLOSE_TIMEOUT_MS_DEFAULT 20000
+#endif
+
+/**
+ * SO_REUSE==1: Enable SO_REUSEADDR option.
+ */
+#if !defined SO_REUSE || defined __DOXYGEN__
+#define SO_REUSE 0
+#endif
+
+/**
+ * SO_REUSE_RXTOALL==1: Pass a copy of incoming broadcast/multicast packets
+ * to all local matches if SO_REUSEADDR is turned on.
+ * WARNING: Adds a memcpy for every packet if passing to more than one pcb!
+ */
+#if !defined SO_REUSE_RXTOALL || defined __DOXYGEN__
+#define SO_REUSE_RXTOALL 0
+#endif
+
+/**
+ * LWIP_FIONREAD_LINUXMODE==0 (default): ioctl/FIONREAD returns the amount of
+ * pending data in the network buffer. This is the way windows does it. It's
+ * the default for lwIP since it is smaller.
+ * LWIP_FIONREAD_LINUXMODE==1: ioctl/FIONREAD returns the size of the next
+ * pending datagram in bytes. This is the way linux does it. This code is only
+ * here for compatibility.
+ */
+#if !defined LWIP_FIONREAD_LINUXMODE || defined __DOXYGEN__
+#define LWIP_FIONREAD_LINUXMODE 0
+#endif
+/**
+ * @}
+ */
+
+/*
+ ----------------------------------------
+ ---------- Statistics options ----------
+ ----------------------------------------
+*/
+/**
+ * @defgroup lwip_opts_stats Statistics
+ * @ingroup lwip_opts_debug
+ * @{
+ */
+/**
+ * LWIP_STATS==1: Enable statistics collection in lwip_stats.
+ */
+#if !defined LWIP_STATS || defined __DOXYGEN__
+#define LWIP_STATS 1
+#endif
+
+#if LWIP_STATS
+
+/**
+ * LWIP_STATS_DISPLAY==1: Compile in the statistics output functions.
+ */
+#if !defined LWIP_STATS_DISPLAY || defined __DOXYGEN__
+#define LWIP_STATS_DISPLAY 0
+#endif
+
+/**
+ * LINK_STATS==1: Enable link stats.
+ */
+#if !defined LINK_STATS || defined __DOXYGEN__
+#define LINK_STATS 1
+#endif
+
+/**
+ * ETHARP_STATS==1: Enable etharp stats.
+ */
+#if !defined ETHARP_STATS || defined __DOXYGEN__
+#define ETHARP_STATS (LWIP_ARP)
+#endif
+
+/**
+ * IP_STATS==1: Enable IP stats.
+ */
+#if !defined IP_STATS || defined __DOXYGEN__
+#define IP_STATS 1
+#endif
+
+/**
+ * IPFRAG_STATS==1: Enable IP fragmentation stats. Default is
+ * on if using either frag or reass.
+ */
+#if !defined IPFRAG_STATS || defined __DOXYGEN__
+#define IPFRAG_STATS (IP_REASSEMBLY || IP_FRAG)
+#endif
+
+/**
+ * ICMP_STATS==1: Enable ICMP stats.
+ */
+#if !defined ICMP_STATS || defined __DOXYGEN__
+#define ICMP_STATS 1
+#endif
+
+/**
+ * IGMP_STATS==1: Enable IGMP stats.
+ */
+#if !defined IGMP_STATS || defined __DOXYGEN__
+#define IGMP_STATS (LWIP_IGMP)
+#endif
+
+/**
+ * UDP_STATS==1: Enable UDP stats. Default is on if
+ * UDP enabled, otherwise off.
+ */
+#if !defined UDP_STATS || defined __DOXYGEN__
+#define UDP_STATS (LWIP_UDP)
+#endif
+
+/**
+ * TCP_STATS==1: Enable TCP stats. Default is on if TCP
+ * enabled, otherwise off.
+ */
+#if !defined TCP_STATS || defined __DOXYGEN__
+#define TCP_STATS (LWIP_TCP)
+#endif
+
+/**
+ * MEM_STATS==1: Enable mem.c stats.
+ */
+#if !defined MEM_STATS || defined __DOXYGEN__
+#define MEM_STATS ((MEM_LIBC_MALLOC == 0) && (MEM_USE_POOLS == 0))
+#endif
+
+/**
+ * MEMP_STATS==1: Enable memp.c pool stats.
+ */
+#if !defined MEMP_STATS || defined __DOXYGEN__
+#define MEMP_STATS (MEMP_MEM_MALLOC == 0)
+#endif
+
+/**
+ * SYS_STATS==1: Enable system stats (sem and mbox counts, etc).
+ */
+#if !defined SYS_STATS || defined __DOXYGEN__
+#define SYS_STATS (NO_SYS == 0)
+#endif
+
+/**
+ * IP6_STATS==1: Enable IPv6 stats.
+ */
+#if !defined IP6_STATS || defined __DOXYGEN__
+#define IP6_STATS (LWIP_IPV6)
+#endif
+
+/**
+ * ICMP6_STATS==1: Enable ICMP for IPv6 stats.
+ */
+#if !defined ICMP6_STATS || defined __DOXYGEN__
+#define ICMP6_STATS (LWIP_IPV6 && LWIP_ICMP6)
+#endif
+
+/**
+ * IP6_FRAG_STATS==1: Enable IPv6 fragmentation stats.
+ */
+#if !defined IP6_FRAG_STATS || defined __DOXYGEN__
+#define IP6_FRAG_STATS (LWIP_IPV6 && (LWIP_IPV6_FRAG || LWIP_IPV6_REASS))
+#endif
+
+/**
+ * MLD6_STATS==1: Enable MLD for IPv6 stats.
+ */
+#if !defined MLD6_STATS || defined __DOXYGEN__
+#define MLD6_STATS (LWIP_IPV6 && LWIP_IPV6_MLD)
+#endif
+
+/**
+ * ND6_STATS==1: Enable Neighbor discovery for IPv6 stats.
+ */
+#if !defined ND6_STATS || defined __DOXYGEN__
+#define ND6_STATS (LWIP_IPV6)
+#endif
+
+/**
+ * MIB2_STATS==1: Stats for SNMP MIB2.
+ */
+#if !defined MIB2_STATS || defined __DOXYGEN__
+#define MIB2_STATS 0
+#endif
+
+#else
+
+#define LINK_STATS 0
+#define ETHARP_STATS 0
+#define IP_STATS 0
+#define IPFRAG_STATS 0
+#define ICMP_STATS 0
+#define IGMP_STATS 0
+#define UDP_STATS 0
+#define TCP_STATS 0
+#define MEM_STATS 0
+#define MEMP_STATS 0
+#define SYS_STATS 0
+#define LWIP_STATS_DISPLAY 0
+#define IP6_STATS 0
+#define ICMP6_STATS 0
+#define IP6_FRAG_STATS 0
+#define MLD6_STATS 0
+#define ND6_STATS 0
+#define MIB2_STATS 0
+
+#endif /* LWIP_STATS */
+/**
+ * @}
+ */
+
+/*
+ --------------------------------------
+ ---------- Checksum options ----------
+ --------------------------------------
+*/
+/**
+ * @defgroup lwip_opts_checksum Checksum
+ * @ingroup lwip_opts_infrastructure
+ * @{
+ */
+/**
+ * LWIP_CHECKSUM_CTRL_PER_NETIF==1: Checksum generation/check can be enabled/disabled
+ * per netif.
+ * ATTENTION: if enabled, the CHECKSUM_GEN_* and CHECKSUM_CHECK_* defines must be enabled!
+ */
+#if !defined LWIP_CHECKSUM_CTRL_PER_NETIF || defined __DOXYGEN__
+#define LWIP_CHECKSUM_CTRL_PER_NETIF 0
+#endif
+
+/**
+ * CHECKSUM_GEN_IP==1: Generate checksums in software for outgoing IP packets.
+ */
+#if !defined CHECKSUM_GEN_IP || defined __DOXYGEN__
+#define CHECKSUM_GEN_IP 1
+#endif
+
+/**
+ * CHECKSUM_GEN_UDP==1: Generate checksums in software for outgoing UDP packets.
+ */
+#if !defined CHECKSUM_GEN_UDP || defined __DOXYGEN__
+#define CHECKSUM_GEN_UDP 1
+#endif
+
+/**
+ * CHECKSUM_GEN_TCP==1: Generate checksums in software for outgoing TCP packets.
+ */
+#if !defined CHECKSUM_GEN_TCP || defined __DOXYGEN__
+#define CHECKSUM_GEN_TCP 1
+#endif
+
+/**
+ * CHECKSUM_GEN_ICMP==1: Generate checksums in software for outgoing ICMP packets.
+ */
+#if !defined CHECKSUM_GEN_ICMP || defined __DOXYGEN__
+#define CHECKSUM_GEN_ICMP 1
+#endif
+
+/**
+ * CHECKSUM_GEN_ICMP6==1: Generate checksums in software for outgoing ICMP6 packets.
+ */
+#if !defined CHECKSUM_GEN_ICMP6 || defined __DOXYGEN__
+#define CHECKSUM_GEN_ICMP6 1
+#endif
+
+/**
+ * CHECKSUM_CHECK_IP==1: Check checksums in software for incoming IP packets.
+ */
+#if !defined CHECKSUM_CHECK_IP || defined __DOXYGEN__
+#define CHECKSUM_CHECK_IP 1
+#endif
+
+/**
+ * CHECKSUM_CHECK_UDP==1: Check checksums in software for incoming UDP packets.
+ */
+#if !defined CHECKSUM_CHECK_UDP || defined __DOXYGEN__
+#define CHECKSUM_CHECK_UDP 1
+#endif
+
+/**
+ * CHECKSUM_CHECK_TCP==1: Check checksums in software for incoming TCP packets.
+ */
+#if !defined CHECKSUM_CHECK_TCP || defined __DOXYGEN__
+#define CHECKSUM_CHECK_TCP 1
+#endif
+
+/**
+ * CHECKSUM_CHECK_ICMP==1: Check checksums in software for incoming ICMP packets.
+ */
+#if !defined CHECKSUM_CHECK_ICMP || defined __DOXYGEN__
+#define CHECKSUM_CHECK_ICMP 1
+#endif
+
+/**
+ * CHECKSUM_CHECK_ICMP6==1: Check checksums in software for incoming ICMPv6 packets
+ */
+#if !defined CHECKSUM_CHECK_ICMP6 || defined __DOXYGEN__
+#define CHECKSUM_CHECK_ICMP6 1
+#endif
+
+/**
+ * LWIP_CHECKSUM_ON_COPY==1: Calculate checksum when copying data from
+ * application buffers to pbufs.
+ */
+#if !defined LWIP_CHECKSUM_ON_COPY || defined __DOXYGEN__
+#define LWIP_CHECKSUM_ON_COPY 0
+#endif
+/**
+ * @}
+ */
+
+/*
+ ---------------------------------------
+ ---------- IPv6 options ---------------
+ ---------------------------------------
+*/
+/**
+ * @defgroup lwip_opts_ipv6 IPv6
+ * @ingroup lwip_opts
+ * @{
+ */
+/**
+ * LWIP_IPV6==1: Enable IPv6
+ */
+#if !defined LWIP_IPV6 || defined __DOXYGEN__
+#define LWIP_IPV6 0
+#endif
+
+/**
+ * LWIP_IPV6_NUM_ADDRESSES: Number of IPv6 addresses per netif.
+ */
+#if !defined LWIP_IPV6_NUM_ADDRESSES || defined __DOXYGEN__
+#define LWIP_IPV6_NUM_ADDRESSES 3
+#endif
+
+/**
+ * LWIP_IPV6_FORWARD==1: Forward IPv6 packets across netifs
+ */
+#if !defined LWIP_IPV6_FORWARD || defined __DOXYGEN__
+#define LWIP_IPV6_FORWARD 0
+#endif
+
+/**
+ * LWIP_IPV6_FRAG==1: Fragment outgoing IPv6 packets that are too big.
+ */
+#if !defined LWIP_IPV6_FRAG || defined __DOXYGEN__
+#define LWIP_IPV6_FRAG 0
+#endif
+
+/**
+ * LWIP_IPV6_REASS==1: reassemble incoming IPv6 packets that fragmented
+ */
+#if !defined LWIP_IPV6_REASS || defined __DOXYGEN__
+#define LWIP_IPV6_REASS (LWIP_IPV6)
+#endif
+
+/**
+ * LWIP_IPV6_SEND_ROUTER_SOLICIT==1: Send router solicitation messages during
+ * network startup.
+ */
+#if !defined LWIP_IPV6_SEND_ROUTER_SOLICIT || defined __DOXYGEN__
+#define LWIP_IPV6_SEND_ROUTER_SOLICIT 1
+#endif
+
+/**
+ * LWIP_IPV6_AUTOCONFIG==1: Enable stateless address autoconfiguration as per RFC 4862.
+ */
+#if !defined LWIP_IPV6_AUTOCONFIG || defined __DOXYGEN__
+#define LWIP_IPV6_AUTOCONFIG (LWIP_IPV6)
+#endif
+
+/**
+ * LWIP_IPV6_DUP_DETECT_ATTEMPTS=[0..7]: Number of duplicate address detection attempts.
+ */
+#if !defined LWIP_IPV6_DUP_DETECT_ATTEMPTS || defined __DOXYGEN__
+#define LWIP_IPV6_DUP_DETECT_ATTEMPTS 1
+#endif
+/**
+ * @}
+ */
+
+/**
+ * @defgroup lwip_opts_icmp6 ICMP6
+ * @ingroup lwip_opts_ipv6
+ * @{
+ */
+/**
+ * LWIP_ICMP6==1: Enable ICMPv6 (mandatory per RFC)
+ */
+#if !defined LWIP_ICMP6 || defined __DOXYGEN__
+#define LWIP_ICMP6 (LWIP_IPV6)
+#endif
+
+/**
+ * LWIP_ICMP6_DATASIZE: bytes from original packet to send back in
+ * ICMPv6 error messages.
+ */
+#if !defined LWIP_ICMP6_DATASIZE || defined __DOXYGEN__
+#define LWIP_ICMP6_DATASIZE 8
+#endif
+
+/**
+ * LWIP_ICMP6_HL: default hop limit for ICMPv6 messages
+ */
+#if !defined LWIP_ICMP6_HL || defined __DOXYGEN__
+#define LWIP_ICMP6_HL 255
+#endif
+/**
+ * @}
+ */
+
+/**
+ * @defgroup lwip_opts_mld6 Multicast listener discovery
+ * @ingroup lwip_opts_ipv6
+ * @{
+ */
+/**
+ * LWIP_IPV6_MLD==1: Enable multicast listener discovery protocol.
+ * If LWIP_IPV6 is enabled but this setting is disabled, the MAC layer must
+ * indiscriminately pass all inbound IPv6 multicast traffic to lwIP.
+ */
+#if !defined LWIP_IPV6_MLD || defined __DOXYGEN__
+#define LWIP_IPV6_MLD (LWIP_IPV6)
+#endif
+
+/**
+ * MEMP_NUM_MLD6_GROUP: Max number of IPv6 multicast groups that can be joined.
+ * There must be enough groups so that each netif can join the solicited-node
+ * multicast group for each of its local addresses, plus one for MDNS if
+ * applicable, plus any number of groups to be joined on UDP sockets.
+ */
+#if !defined MEMP_NUM_MLD6_GROUP || defined __DOXYGEN__
+#define MEMP_NUM_MLD6_GROUP 4
+#endif
+/**
+ * @}
+ */
+
+/**
+ * @defgroup lwip_opts_nd6 Neighbor discovery
+ * @ingroup lwip_opts_ipv6
+ * @{
+ */
+/**
+ * LWIP_ND6_QUEUEING==1: queue outgoing IPv6 packets while MAC address
+ * is being resolved.
+ */
+#if !defined LWIP_ND6_QUEUEING || defined __DOXYGEN__
+#define LWIP_ND6_QUEUEING (LWIP_IPV6)
+#endif
+
+/**
+ * MEMP_NUM_ND6_QUEUE: Max number of IPv6 packets to queue during MAC resolution.
+ */
+#if !defined MEMP_NUM_ND6_QUEUE || defined __DOXYGEN__
+#define MEMP_NUM_ND6_QUEUE 20
+#endif
+
+/**
+ * LWIP_ND6_NUM_NEIGHBORS: Number of entries in IPv6 neighbor cache
+ */
+#if !defined LWIP_ND6_NUM_NEIGHBORS || defined __DOXYGEN__
+#define LWIP_ND6_NUM_NEIGHBORS 10
+#endif
+
+/**
+ * LWIP_ND6_NUM_DESTINATIONS: number of entries in IPv6 destination cache
+ */
+#if !defined LWIP_ND6_NUM_DESTINATIONS || defined __DOXYGEN__
+#define LWIP_ND6_NUM_DESTINATIONS 10
+#endif
+
+/**
+ * LWIP_ND6_NUM_PREFIXES: number of entries in IPv6 on-link prefixes cache
+ */
+#if !defined LWIP_ND6_NUM_PREFIXES || defined __DOXYGEN__
+#define LWIP_ND6_NUM_PREFIXES 5
+#endif
+
+/**
+ * LWIP_ND6_NUM_ROUTERS: number of entries in IPv6 default router cache
+ */
+#if !defined LWIP_ND6_NUM_ROUTERS || defined __DOXYGEN__
+#define LWIP_ND6_NUM_ROUTERS 3
+#endif
+
+/**
+ * LWIP_ND6_MAX_MULTICAST_SOLICIT: max number of multicast solicit messages to send
+ * (neighbor solicit and router solicit)
+ */
+#if !defined LWIP_ND6_MAX_MULTICAST_SOLICIT || defined __DOXYGEN__
+#define LWIP_ND6_MAX_MULTICAST_SOLICIT 3
+#endif
+
+/**
+ * LWIP_ND6_MAX_UNICAST_SOLICIT: max number of unicast neighbor solicitation messages
+ * to send during neighbor reachability detection.
+ */
+#if !defined LWIP_ND6_MAX_UNICAST_SOLICIT || defined __DOXYGEN__
+#define LWIP_ND6_MAX_UNICAST_SOLICIT 3
+#endif
+
+/**
+ * Unused: See ND RFC (time in milliseconds).
+ */
+#if !defined LWIP_ND6_MAX_ANYCAST_DELAY_TIME || defined __DOXYGEN__
+#define LWIP_ND6_MAX_ANYCAST_DELAY_TIME 1000
+#endif
+
+/**
+ * Unused: See ND RFC
+ */
+#if !defined LWIP_ND6_MAX_NEIGHBOR_ADVERTISEMENT || defined __DOXYGEN__
+#define LWIP_ND6_MAX_NEIGHBOR_ADVERTISEMENT 3
+#endif
+
+/**
+ * LWIP_ND6_REACHABLE_TIME: default neighbor reachable time (in milliseconds).
+ * May be updated by router advertisement messages.
+ */
+#if !defined LWIP_ND6_REACHABLE_TIME || defined __DOXYGEN__
+#define LWIP_ND6_REACHABLE_TIME 30000
+#endif
+
+/**
+ * LWIP_ND6_RETRANS_TIMER: default retransmission timer for solicitation messages
+ */
+#if !defined LWIP_ND6_RETRANS_TIMER || defined __DOXYGEN__
+#define LWIP_ND6_RETRANS_TIMER 1000
+#endif
+
+/**
+ * LWIP_ND6_DELAY_FIRST_PROBE_TIME: Delay before first unicast neighbor solicitation
+ * message is sent, during neighbor reachability detection.
+ */
+#if !defined LWIP_ND6_DELAY_FIRST_PROBE_TIME || defined __DOXYGEN__
+#define LWIP_ND6_DELAY_FIRST_PROBE_TIME 5000
+#endif
+
+/**
+ * LWIP_ND6_ALLOW_RA_UPDATES==1: Allow Router Advertisement messages to update
+ * Reachable time and retransmission timers, and netif MTU.
+ */
+#if !defined LWIP_ND6_ALLOW_RA_UPDATES || defined __DOXYGEN__
+#define LWIP_ND6_ALLOW_RA_UPDATES 1
+#endif
+
+/**
+ * LWIP_ND6_TCP_REACHABILITY_HINTS==1: Allow TCP to provide Neighbor Discovery
+ * with reachability hints for connected destinations. This helps avoid sending
+ * unicast neighbor solicitation messages.
+ */
+#if !defined LWIP_ND6_TCP_REACHABILITY_HINTS || defined __DOXYGEN__
+#define LWIP_ND6_TCP_REACHABILITY_HINTS 1
+#endif
+
+/**
+ * LWIP_ND6_RDNSS_MAX_DNS_SERVERS > 0: Use IPv6 Router Advertisement Recursive
+ * DNS Server Option (as per RFC 6106) to copy a defined maximum number of DNS
+ * servers to the DNS module.
+ */
+#if !defined LWIP_ND6_RDNSS_MAX_DNS_SERVERS || defined __DOXYGEN__
+#define LWIP_ND6_RDNSS_MAX_DNS_SERVERS 0
+#endif
+/**
+ * @}
+ */
+
+/**
+ * LWIP_IPV6_DHCP6==1: enable DHCPv6 stateful address autoconfiguration.
+ */
+#if !defined LWIP_IPV6_DHCP6 || defined __DOXYGEN__
+#define LWIP_IPV6_DHCP6 0
+#endif
+
+/*
+ ---------------------------------------
+ ---------- Hook options ---------------
+ ---------------------------------------
+*/
+
+/**
+ * @defgroup lwip_opts_hooks Hooks
+ * @ingroup lwip_opts_infrastructure
+ * Hooks are undefined by default, define them to a function if you need them.
+ * @{
+ */
+
+/**
+ * LWIP_HOOK_FILENAME: Custom filename to #include in files that provide hooks.
+ * Declare your hook function prototypes in there, you may also #include all headers
+ * providing data types that are need in this file.
+ */
+#ifdef __DOXYGEN__
+#define LWIP_HOOK_FILENAME "path/to/my/lwip_hooks.h"
+#endif
+
+/**
+ * LWIP_HOOK_TCP_ISN:
+ * Hook for generation of the Initial Sequence Number (ISN) for a new TCP
+ * connection. The default lwIP ISN generation algorithm is very basic and may
+ * allow for TCP spoofing attacks. This hook provides the means to implement
+ * the standardized ISN generation algorithm from RFC 6528 (see contrib/adons/tcp_isn),
+ * or any other desired algorithm as a replacement.
+ * Called from tcp_connect() and tcp_listen_input() when an ISN is needed for
+ * a new TCP connection, if TCP support (@ref LWIP_TCP) is enabled.\n
+ * Signature: u32_t my_hook_tcp_isn(const ip_addr_t* local_ip, u16_t local_port, const ip_addr_t* remote_ip, u16_t remote_port);
+ * - it may be necessary to use "struct ip_addr" (ip4_addr, ip6_addr) instead of "ip_addr_t" in function declarations\n
+ * Arguments:
+ * - local_ip: pointer to the local IP address of the connection
+ * - local_port: local port number of the connection (host-byte order)
+ * - remote_ip: pointer to the remote IP address of the connection
+ * - remote_port: remote port number of the connection (host-byte order)\n
+ * Return value:
+ * - the 32-bit Initial Sequence Number to use for the new TCP connection.
+ */
+#ifdef __DOXYGEN__
+#define LWIP_HOOK_TCP_ISN(local_ip, local_port, remote_ip, remote_port)
+#endif
+
+/**
+ * LWIP_HOOK_IP4_INPUT(pbuf, input_netif):
+ * - called from ip_input() (IPv4)
+ * - pbuf: received struct pbuf passed to ip_input()
+ * - input_netif: struct netif on which the packet has been received
+ * Return values:
+ * - 0: Hook has not consumed the packet, packet is processed as normal
+ * - != 0: Hook has consumed the packet.
+ * If the hook consumed the packet, 'pbuf' is in the responsibility of the hook
+ * (i.e. free it when done).
+ */
+#ifdef __DOXYGEN__
+#define LWIP_HOOK_IP4_INPUT(pbuf, input_netif)
+#endif
+
+/**
+ * LWIP_HOOK_IP4_ROUTE(dest):
+ * - called from ip_route() (IPv4)
+ * - dest: destination IPv4 address
+ * Returns the destination netif or NULL if no destination netif is found. In
+ * that case, ip_route() continues as normal.
+ */
+#ifdef __DOXYGEN__
+#define LWIP_HOOK_IP4_ROUTE()
+#endif
+
+/**
+ * LWIP_HOOK_IP4_ROUTE_SRC(dest, src):
+ * - source-based routing for IPv4 (see LWIP_HOOK_IP4_ROUTE(), src may be NULL)
+ */
+#ifdef __DOXYGEN__
+#define LWIP_HOOK_IP4_ROUTE_SRC(dest, src)
+#endif
+
+/**
+ * LWIP_HOOK_ETHARP_GET_GW(netif, dest):
+ * - called from etharp_output() (IPv4)
+ * - netif: the netif used for sending
+ * - dest: the destination IPv4 address
+ * Returns the IPv4 address of the gateway to handle the specified destination
+ * IPv4 address. If NULL is returned, the netif's default gateway is used.
+ * The returned address MUST be directly reachable on the specified netif!
+ * This function is meant to implement advanced IPv4 routing together with
+ * LWIP_HOOK_IP4_ROUTE(). The actual routing/gateway table implementation is
+ * not part of lwIP but can e.g. be hidden in the netif's state argument.
+*/
+#ifdef __DOXYGEN__
+#define LWIP_HOOK_ETHARP_GET_GW(netif, dest)
+#endif
+
+/**
+ * LWIP_HOOK_IP6_INPUT(pbuf, input_netif):
+ * - called from ip6_input() (IPv6)
+ * - pbuf: received struct pbuf passed to ip6_input()
+ * - input_netif: struct netif on which the packet has been received
+ * Return values:
+ * - 0: Hook has not consumed the packet, packet is processed as normal
+ * - != 0: Hook has consumed the packet.
+ * If the hook consumed the packet, 'pbuf' is in the responsibility of the hook
+ * (i.e. free it when done).
+ */
+#ifdef __DOXYGEN__
+#define LWIP_HOOK_IP6_INPUT(pbuf, input_netif)
+#endif
+
+/**
+ * LWIP_HOOK_IP6_ROUTE(src, dest):
+ * - called from ip6_route() (IPv6)
+ * - src: sourc IPv6 address
+ * - dest: destination IPv6 address
+ * Returns the destination netif or NULL if no destination netif is found. In
+ * that case, ip6_route() continues as normal.
+ */
+#ifdef __DOXYGEN__
+#define LWIP_HOOK_IP6_ROUTE(src, dest)
+#endif
+
+/**
+ * LWIP_HOOK_ND6_GET_GW(netif, dest):
+ * - called from nd6_get_next_hop_entry() (IPv6)
+ * - netif: the netif used for sending
+ * - dest: the destination IPv6 address
+ * Returns the IPv6 address of the next hop to handle the specified destination
+ * IPv6 address. If NULL is returned, a NDP-discovered router is used instead.
+ * The returned address MUST be directly reachable on the specified netif!
+ * This function is meant to implement advanced IPv6 routing together with
+ * LWIP_HOOK_IP6_ROUTE(). The actual routing/gateway table implementation is
+ * not part of lwIP but can e.g. be hidden in the netif's state argument.
+*/
+#ifdef __DOXYGEN__
+#define LWIP_HOOK_ND6_GET_GW(netif, dest)
+#endif
+
+/**
+ * LWIP_HOOK_VLAN_CHECK(netif, eth_hdr, vlan_hdr):
+ * - called from ethernet_input() if VLAN support is enabled
+ * - netif: struct netif on which the packet has been received
+ * - eth_hdr: struct eth_hdr of the packet
+ * - vlan_hdr: struct eth_vlan_hdr of the packet
+ * Return values:
+ * - 0: Packet must be dropped.
+ * - != 0: Packet must be accepted.
+ */
+#ifdef __DOXYGEN__
+#define LWIP_HOOK_VLAN_CHECK(netif, eth_hdr, vlan_hdr)
+#endif
+
+/**
+ * LWIP_HOOK_VLAN_SET:
+ * Hook can be used to set prio_vid field of vlan_hdr. If you need to store data
+ * on per-netif basis to implement this callback, see @ref netif_cd.
+ * Called from ethernet_output() if VLAN support (@ref ETHARP_SUPPORT_VLAN) is enabled.\n
+ * Signature: s32_t my_hook_vlan_set(struct netif* netif, struct pbuf* pbuf, const struct eth_addr* src, const struct eth_addr* dst, u16_t eth_type);\n
+ * Arguments:
+ * - netif: struct netif that the packet will be sent through
+ * - p: struct pbuf packet to be sent
+ * - src: source eth address
+ * - dst: destination eth address
+ * - eth_type: ethernet type to packet to be sent\n
+ *
+ *
+ * Return values:
+ * - &lt;0: Packet shall not contain VLAN header.
+ * - 0 &lt;= return value &lt;= 0xFFFF: Packet shall contain VLAN header. Return value is prio_vid in host byte order.
+ */
+#ifdef __DOXYGEN__
+#define LWIP_HOOK_VLAN_SET(netif, p, src, dst, eth_type)
+#endif
+
+/**
+ * LWIP_HOOK_MEMP_AVAILABLE(memp_t_type):
+ * - called from memp_free() when a memp pool was empty and an item is now available
+ */
+#ifdef __DOXYGEN__
+#define LWIP_HOOK_MEMP_AVAILABLE(memp_t_type)
+#endif
+
+/**
+ * LWIP_HOOK_UNKNOWN_ETH_PROTOCOL(pbuf, netif):
+ * Called from ethernet_input() when an unknown eth type is encountered.
+ * Return ERR_OK if packet is accepted, any error code otherwise.
+ * Payload points to ethernet header!
+ */
+#ifdef __DOXYGEN__
+#define LWIP_HOOK_UNKNOWN_ETH_PROTOCOL(pbuf, netif)
+#endif
+/**
+ * @}
+ */
+
+/*
+ ---------------------------------------
+ ---------- Debugging options ----------
+ ---------------------------------------
+*/
+/**
+ * @defgroup lwip_opts_debugmsg Debug messages
+ * @ingroup lwip_opts_debug
+ * @{
+ */
+/**
+ * LWIP_DBG_MIN_LEVEL: After masking, the value of the debug is
+ * compared against this value. If it is smaller, then debugging
+ * messages are written.
+ * @see debugging_levels
+ */
+#if !defined LWIP_DBG_MIN_LEVEL || defined __DOXYGEN__
+#define LWIP_DBG_MIN_LEVEL LWIP_DBG_LEVEL_ALL
+#endif
+
+/**
+ * LWIP_DBG_TYPES_ON: A mask that can be used to globally enable/disable
+ * debug messages of certain types.
+ * @see debugging_levels
+ */
+#if !defined LWIP_DBG_TYPES_ON || defined __DOXYGEN__
+#define LWIP_DBG_TYPES_ON LWIP_DBG_ON
+#endif
+
+/**
+ * ETHARP_DEBUG: Enable debugging in etharp.c.
+ */
+#if !defined ETHARP_DEBUG || defined __DOXYGEN__
+#define ETHARP_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * NETIF_DEBUG: Enable debugging in netif.c.
+ */
+#if !defined NETIF_DEBUG || defined __DOXYGEN__
+#define NETIF_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * PBUF_DEBUG: Enable debugging in pbuf.c.
+ */
+#if !defined PBUF_DEBUG || defined __DOXYGEN__
+#define PBUF_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * API_LIB_DEBUG: Enable debugging in api_lib.c.
+ */
+#if !defined API_LIB_DEBUG || defined __DOXYGEN__
+#define API_LIB_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * API_MSG_DEBUG: Enable debugging in api_msg.c.
+ */
+#if !defined API_MSG_DEBUG || defined __DOXYGEN__
+#define API_MSG_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * SOCKETS_DEBUG: Enable debugging in sockets.c.
+ */
+#if !defined SOCKETS_DEBUG || defined __DOXYGEN__
+#define SOCKETS_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * ICMP_DEBUG: Enable debugging in icmp.c.
+ */
+#if !defined ICMP_DEBUG || defined __DOXYGEN__
+#define ICMP_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * IGMP_DEBUG: Enable debugging in igmp.c.
+ */
+#if !defined IGMP_DEBUG || defined __DOXYGEN__
+#define IGMP_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * INET_DEBUG: Enable debugging in inet.c.
+ */
+#if !defined INET_DEBUG || defined __DOXYGEN__
+#define INET_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * IP_DEBUG: Enable debugging for IP.
+ */
+#if !defined IP_DEBUG || defined __DOXYGEN__
+#define IP_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * IP_REASS_DEBUG: Enable debugging in ip_frag.c for both frag & reass.
+ */
+#if !defined IP_REASS_DEBUG || defined __DOXYGEN__
+#define IP_REASS_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * RAW_DEBUG: Enable debugging in raw.c.
+ */
+#if !defined RAW_DEBUG || defined __DOXYGEN__
+#define RAW_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * MEM_DEBUG: Enable debugging in mem.c.
+ */
+#if !defined MEM_DEBUG || defined __DOXYGEN__
+#define MEM_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * MEMP_DEBUG: Enable debugging in memp.c.
+ */
+#if !defined MEMP_DEBUG || defined __DOXYGEN__
+#define MEMP_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * SYS_DEBUG: Enable debugging in sys.c.
+ */
+#if !defined SYS_DEBUG || defined __DOXYGEN__
+#define SYS_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * TIMERS_DEBUG: Enable debugging in timers.c.
+ */
+#if !defined TIMERS_DEBUG || defined __DOXYGEN__
+#define TIMERS_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * TCP_DEBUG: Enable debugging for TCP.
+ */
+#if !defined TCP_DEBUG || defined __DOXYGEN__
+#define TCP_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * TCP_INPUT_DEBUG: Enable debugging in tcp_in.c for incoming debug.
+ */
+#if !defined TCP_INPUT_DEBUG || defined __DOXYGEN__
+#define TCP_INPUT_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * TCP_FR_DEBUG: Enable debugging in tcp_in.c for fast retransmit.
+ */
+#if !defined TCP_FR_DEBUG || defined __DOXYGEN__
+#define TCP_FR_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * TCP_RTO_DEBUG: Enable debugging in TCP for retransmit
+ * timeout.
+ */
+#if !defined TCP_RTO_DEBUG || defined __DOXYGEN__
+#define TCP_RTO_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * TCP_CWND_DEBUG: Enable debugging for TCP congestion window.
+ */
+#if !defined TCP_CWND_DEBUG || defined __DOXYGEN__
+#define TCP_CWND_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * TCP_WND_DEBUG: Enable debugging in tcp_in.c for window updating.
+ */
+#if !defined TCP_WND_DEBUG || defined __DOXYGEN__
+#define TCP_WND_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * TCP_OUTPUT_DEBUG: Enable debugging in tcp_out.c output functions.
+ */
+#if !defined TCP_OUTPUT_DEBUG || defined __DOXYGEN__
+#define TCP_OUTPUT_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * TCP_RST_DEBUG: Enable debugging for TCP with the RST message.
+ */
+#if !defined TCP_RST_DEBUG || defined __DOXYGEN__
+#define TCP_RST_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * TCP_QLEN_DEBUG: Enable debugging for TCP queue lengths.
+ */
+#if !defined TCP_QLEN_DEBUG || defined __DOXYGEN__
+#define TCP_QLEN_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * UDP_DEBUG: Enable debugging in UDP.
+ */
+#if !defined UDP_DEBUG || defined __DOXYGEN__
+#define UDP_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * TCPIP_DEBUG: Enable debugging in tcpip.c.
+ */
+#if !defined TCPIP_DEBUG || defined __DOXYGEN__
+#define TCPIP_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * SLIP_DEBUG: Enable debugging in slipif.c.
+ */
+#if !defined SLIP_DEBUG || defined __DOXYGEN__
+#define SLIP_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * DHCP_DEBUG: Enable debugging in dhcp.c.
+ */
+#if !defined DHCP_DEBUG || defined __DOXYGEN__
+#define DHCP_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * AUTOIP_DEBUG: Enable debugging in autoip.c.
+ */
+#if !defined AUTOIP_DEBUG || defined __DOXYGEN__
+#define AUTOIP_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * DNS_DEBUG: Enable debugging for DNS.
+ */
+#if !defined DNS_DEBUG || defined __DOXYGEN__
+#define DNS_DEBUG LWIP_DBG_OFF
+#endif
+
+/**
+ * IP6_DEBUG: Enable debugging for IPv6.
+ */
+#if !defined IP6_DEBUG || defined __DOXYGEN__
+#define IP6_DEBUG LWIP_DBG_OFF
+#endif
+/**
+ * @}
+ */
+
+/*
+ --------------------------------------------------
+ ---------- Performance tracking options ----------
+ --------------------------------------------------
+*/
+/**
+ * @defgroup lwip_opts_perf Performance
+ * @ingroup lwip_opts_debug
+ * @{
+ */
+/**
+ * LWIP_PERF: Enable performance testing for lwIP
+ * (if enabled, arch/perf.h is included)
+ */
+#if !defined LWIP_PERF || defined __DOXYGEN__
+#define LWIP_PERF 0
+#endif
+/**
+ * @}
+ */
+
+#endif /* LWIP_HDR_OPT_H */