Mbed OS Reference | opt.h Source File

Go to the documentation of this file.
 /**
  * @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
 
 /**
  * MEMMOVE: override this if you have a faster implementation at hand than the
  * one included in your C library.  lwIP currently uses MEMMOVE only when IPv6
  * fragmentation support is enabled.
  */
 #if !defined MEMMOVE || defined __DOXYGEN__
 #define MEMMOVE(dst,src,len)            memmove(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
 
 /**
  * Macro/function to check whether lwIP's threading/locking
  * requirements are satisfied during current function call.
  * This macro usually calls a function that is implemented in the OS-dependent
  * sys layer and performs the following checks:
  * - Not in ISR (this should be checked for NO_SYS==1, too!)
  * - If @ref LWIP_TCPIP_CORE_LOCKING = 1: TCPIP core lock is held
  * - If @ref LWIP_TCPIP_CORE_LOCKING = 0: function is called from TCPIP thread
  * @see @ref multithreading
  */
 #if !defined LWIP_ASSERT_CORE_LOCKED || defined __DOXYGEN__
 #define LWIP_ASSERT_CORE_LOCKED()
 #endif
 
 /**
  * Called as first thing in the lwIP TCPIP thread. Can be used in conjunction
  * with @ref LWIP_ASSERT_CORE_LOCKED to check core locking.
  * @see @ref multithreading
  */
 #if !defined LWIP_MARK_TCPIP_THREAD || defined __DOXYGEN__
 #define LWIP_MARK_TCPIP_THREAD()
 #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
 
 /**
  * MEMP_MEM_INIT==1: Force use of memset to initialize pool memory.
  * Useful if pool are moved in uninitialized section of memory. This will ensure
  * default values in pcbs struct are well initialized in all conditions.
  */
 #if !defined MEMP_MEM_INIT || defined __DOXYGEN__
 #define MEMP_MEM_INIT                   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_OVERFLOW_CHECK: mem overflow protection reserves a configurable
  * amount of bytes before and after each heap allocation chunk and fills
  * it with a prominent default value.
  *    MEM_OVERFLOW_CHECK == 0 no checking
  *    MEM_OVERFLOW_CHECK == 1 checks each element when it is freed
  *    MEM_OVERFLOW_CHECK >= 2 checks all heap elements every time
  *      mem_malloc() or mem_free() is called (useful but slow!)
  */
 #if !defined MEM_OVERFLOW_CHECK || defined __DOXYGEN__
 #define MEM_OVERFLOW_CHECK              0
 #endif
 
 /**
  * MEM_SANITY_CHECK==1: run a sanity check after each mem_free() to make
  * sure that the linked list of heap elements is not corrupted.
  */
 #if !defined MEM_SANITY_CHECK || defined __DOXYGEN__
 #define MEM_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_ALTCP_PCB: the number of simultaneously active altcp layer pcbs.
  * (requires the LWIP_ALTCP option)
  * Connections with multiple layers require more than one altcp_pcb (e.g. TLS
  * over TCP requires 2 altcp_pcbs, one for TLS and one for TCP).
  */
 #if !defined MEMP_NUM_ALTCP_PCB || defined __DOXYGEN__
 #define MEMP_NUM_ALTCP_PCB              MEMP_NUM_TCP_PCB
 #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
 
 /**
  * The number of sys timeouts used by the core stack (not apps)
  * The default number of timeouts is calculated here for all enabled modules.
  */
 #define LWIP_NUM_SYS_TIMEOUT_INTERNAL   (LWIP_TCP + IP_REASSEMBLY + LWIP_ARP + (2*LWIP_DHCP) + LWIP_AUTOIP + LWIP_IGMP + LWIP_DNS + (LWIP_IPV6 * (1 + LWIP_IPV6_REASS + LWIP_IPV6_MLD)))
 
 /**
  * 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_NUM_SYS_TIMEOUT_INTERNAL
 #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_SELECT_CB: the number of struct lwip_select_cb.
  * (Only needed if you have LWIP_MPU_COMPATIBLE==1 and use the socket API.
  * In that case, you need one per thread calling lwip_select.)
  */
 #if !defined MEMP_NUM_SELECT_CB || defined __DOXYGEN__
 #define MEMP_NUM_SELECT_CB              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        !LWIP_SINGLE_NETIF
 #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                 15
 #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!
  * When IPv4 *and* IPv6 are enabled, this even changes to
  * (PBUF_POOL_SIZE > 2 * IP_REASS_MAX_PBUFS)!
  */
 #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
 /**
  * @}
  */
 
 /*
    ----------------------------------
    ---------- 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_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.
  * DNS 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 options -------
    ----------------------------------
 */
 /**
  * @defgroup lwip_opts_multicast Multicast
  * @ingroup lwip_opts_infrastructure
  * @{
  */
 /**
  * LWIP_MULTICAST_TX_OPTIONS==1: Enable multicast TX support like the socket options
  * IP_MULTICAST_TTL/IP_MULTICAST_IF/IP_MULTICAST_LOOP, as well as (currently only)
  * core support for the corresponding IPv6 options.
  */
 #if !defined LWIP_MULTICAST_TX_OPTIONS || defined __DOXYGEN__
 #define LWIP_MULTICAST_TX_OPTIONS       ((LWIP_IGMP || LWIP_IPV6_MLD) && (LWIP_UDP || LWIP_RAW))
 #endif
 /**
  * @}
  */
 
 /*
    ----------------------------------
    ---------- 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
 /**
  * @}
  */
 
 /*
    ----------------------------------
    ---------- 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 maximum number of retries when asking for a name, before "timeout". */
 #if !defined DNS_MAX_RETRIES || defined __DOXYGEN__
 #define DNS_MAX_RETRIES                 4
 #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
 
 /**
  * LWIP_TCP_SACK_OUT==1: TCP will support sending selective acknowledgements (SACKs).
  */
 #if !defined LWIP_TCP_SACK_OUT || defined __DOXYGEN__
 #define LWIP_TCP_SACK_OUT               0
 #endif
 
 /**
  * LWIP_TCP_MAX_SACK_NUM: The maximum number of SACK values to include in TCP segments.
  * Must be at least 1, but is only used if LWIP_TCP_SACK_OUT is enabled.
  * NOTE: Even though we never send more than 3 or 4 SACK ranges in a single segment
  * (depending on other options), setting this option to values greater than 4 is not pointless.
  * This is basically the max number of SACK ranges we want to keep track of.
  * As new data is delivered, some of the SACK ranges may be removed or merged.
  * In that case some of those older SACK ranges may be used again.
  * The amount of memory used to store SACK ranges is LWIP_TCP_MAX_SACK_NUM * 8 bytes for each TCP PCB.
  */
 #if !defined LWIP_TCP_MAX_SACK_NUM || defined __DOXYGEN__
 #define LWIP_TCP_MAX_SACK_NUM           4
 #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 default maximum number of bytes queued on ooseq per
  * pcb if TCP_OOSEQ_BYTES_LIMIT is not defined. 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_BYTES_LIMIT(pcb): Return the maximum number of bytes to be queued
  * on ooseq per pcb, given the pcb. Only valid for TCP_QUEUE_OOSEQ==1 &&
  * TCP_OOSEQ_MAX_BYTES==1.
  * Use this to override TCP_OOSEQ_MAX_BYTES to a dynamic value per pcb.
  */
 #if !defined TCP_OOSEQ_BYTES_LIMIT
 #if TCP_OOSEQ_MAX_BYTES
 #define TCP_OOSEQ_BYTES_LIMIT(pcb)      TCP_OOSEQ_MAX_BYTES
 #elif defined __DOXYGEN__
 #define TCP_OOSEQ_BYTES_LIMIT(pcb)
 #endif
 #endif
 
 /**
  * TCP_OOSEQ_MAX_PBUFS: The default maximum number of pbufs queued on ooseq per
  * pcb if TCP_OOSEQ_BYTES_LIMIT is not defined. 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_OOSEQ_PBUFS_LIMIT(pcb): Return the maximum number of pbufs to be queued
  * on ooseq per pcb, given the pcb.  Only valid for TCP_QUEUE_OOSEQ==1 &&
  * TCP_OOSEQ_MAX_PBUFS==1.
  * Use this to override TCP_OOSEQ_MAX_PBUFS to a dynamic value per pcb.
  */
 #if !defined TCP_OOSEQ_PBUFS_LIMIT
 #if TCP_OOSEQ_MAX_PBUFS
 #define TCP_OOSEQ_PBUFS_LIMIT(pcb)      TCP_OOSEQ_MAX_PBUFS
 #elif defined __DOXYGEN__
 #define TCP_OOSEQ_PBUFS_LIMIT(pcb)
 #endif
 #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
 
 /**
  * LWIP_TCP_PCB_NUM_EXT_ARGS:
  * When this is > 0, every tcp pcb (including listen pcb) includes a number of
  * additional argument entries in an array (see tcp_ext_arg_alloc_id)
  */
 #if !defined LWIP_TCP_PCB_NUM_EXT_ARGS || defined __DOXYGEN__
 #define LWIP_TCP_PCB_NUM_EXT_ARGS       0
 #endif
 
 /** LWIP_ALTCP==1: enable the altcp API.
  * altcp is an abstraction layer that prevents applications linking against the
  * tcp.h functions but provides the same functionality. It is used to e.g. add
  * SSL/TLS or proxy-connect support to an application written for the tcp callback
  * API without that application knowing the protocol details.
  *
  * With LWIP_ALTCP==0, applications written against the altcp API can still be
  * compiled but are directly linked against the tcp.h callback API and then
  * cannot use layered protocols.
  *
  * See @ref altcp_api
  */
 #if !defined LWIP_ALTCP || defined __DOXYGEN__
 #define LWIP_ALTCP                      0
 #endif
 
 /** LWIP_ALTCP_TLS==1: enable TLS support for altcp API.
  * This needs a port of the functions in altcp_tls.h to a TLS library.
  * A port to ARM mbedtls is provided with lwIP, see apps/altcp_tls/ directory
  * and LWIP_ALTCP_TLS_MBEDTLS option.
  */
 #if !defined LWIP_ALTCP_TLS || defined __DOXYGEN__
 #define LWIP_ALTCP_TLS                  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    0
 #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
 
 /**
  * LWIP_PBUF_REF_T: Refcount type in pbuf.
  * Default width of u8_t can be increased if 255 refs are not enough for you.
  */
 #if !defined LWIP_PBUF_REF_T || defined __DOXYGEN__
 #define LWIP_PBUF_REF_T                 u8_t
 #endif
 /**
  * @}
  */
 
 /*
    ------------------------------------------------
    ---------- Network Interfaces options ----------
    ------------------------------------------------
 */
 /**
  * @defgroup lwip_opts_netif NETIF
  * @ingroup lwip_opts
  * @{
  */
 /**
  * LWIP_SINGLE_NETIF==1: use a single netif only. This is the common case for
  * small real-life targets. Some code like routing etc. can be left out.
  */
 #if !defined LWIP_SINGLE_NETIF || defined __DOXYGEN__
 #define LWIP_SINGLE_NETIF               0
 #endif
 
 /**
  * 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_EXT_STATUS_CALLBACK==1: Support an extended callback function 
  * for several netif related event that supports multiple subscribers.
  * @see netif_ext_status_callback
  */
 #if !defined LWIP_NETIF_EXT_STATUS_CALLBACK || defined __DOXYGEN__
 #define LWIP_NETIF_EXT_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!
  *
  * ATTENTION: a driver should *NOT* rely on getting single pbufs but check TX
  * pbufs for being in one piece. If not, @ref pbuf_clone can be used to get
  * a single pbuf:
  *   if (p->next != NULL) {
  *     struct pbuf *q = pbuf_clone(PBUF_RAW, PBUF_RAM, p);
  *     if (q == NULL) {
  *       return ERR_MEM;
  *     }
  *     p = q; ATTENTION: do NOT free the old 'p' as the ref belongs to the caller!
  *   }
  */
 #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 (max. 256).
  */
 #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 && !LWIP_SINGLE_NETIF)
 #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              "lwip_tcpip"
 #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_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
 
 /**
  * LWIP_SOCKET_SELECT==1 (default): enable select() for sockets (uses a netconn
  * callback to keep track of events).
  * This saves RAM (counters per socket) and code (netconn event callback), which
  * should improve performance a bit).
  */
 #if !defined LWIP_SOCKET_SELECT || defined __DOXYGEN__
 #define LWIP_SOCKET_SELECT              1
 #endif
 
 /**
  * LWIP_SOCKET_POLL==1 (default): enable poll() for sockets (including
  * struct pollfd, nfds_t, and constants)
  */
 #if !defined LWIP_SOCKET_POLL || defined __DOXYGEN__
 #define LWIP_SOCKET_POLL                1
 #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
 
 /**
  * IPV6_REASS_MAXAGE: Maximum time (in multiples of IP6_REASS_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 IPV6_REASS_MAXAGE || defined __DOXYGEN__
 #define IPV6_REASS_MAXAGE               60
 #endif
 
 /**
  * LWIP_IPV6_SCOPES==1: Enable support for IPv6 address scopes, ensuring that
  * e.g. link-local addresses are really treated as link-local. Disable this
  * setting only for single-interface configurations.
  * All addresses that have a scope according to the default policy (link-local
  * unicast addresses, interface-local and link-local multicast addresses) should
  * now have a zone set on them before being passed to the core API, although
  * lwIP will currently attempt to select a zone on the caller's behalf when 
  * necessary. Applications that directly assign IPv6 addresses to interfaces
  * (which is NOT recommended) must now ensure that link-local addresses carry
  * the netif's zone. See the new ip6_zone.h header file for more information and
  * relevant macros. For now it is still possible to turn off scopes support
  * through the new LWIP_IPV6_SCOPES option. When upgrading an implementation that
  * uses the core API directly, it is highly recommended to enable
  * LWIP_IPV6_SCOPES_DEBUG at least for a while, to ensure e.g. proper address
  * initialization.
  */
 #if !defined LWIP_IPV6_SCOPES || defined __DOXYGEN__
 #define LWIP_IPV6_SCOPES                0 /*(LWIP_IPV6 && !LWIP_SINGLE_NETIF)*/
 #endif
 
 /**
  * LWIP_IPV6_SCOPES_DEBUG==1: Perform run-time checks to verify that addresses
  * are properly zoned (see ip6_zone.h on what that means) where it matters.
  * Enabling this setting is highly recommended when upgrading from an existing
  * installation that is not yet scope-aware; otherwise it may be too expensive.
  */
 #if !defined LWIP_IPV6_SCOPES_DEBUG || defined __DOXYGEN__
 #define LWIP_IPV6_SCOPES_DEBUG          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                  1
 #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_ADDRESS_LIFETIMES==1: Keep valid and preferred lifetimes for each
  * IPv6 address. Required for LWIP_IPV6_AUTOCONFIG. May still be enabled
  * otherwise, in which case the application may assign address lifetimes with
  * the appropriate macros. Addresses with no lifetime are assumed to be static.
  * If this option is disabled, all addresses are assumed to be static.
  */
 #if !defined LWIP_IPV6_ADDRESS_LIFETIMES || defined __DOXYGEN__
 #define LWIP_IPV6_ADDRESS_LIFETIMES     LWIP_IPV6_AUTOCONFIG
 #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
 /**
  * @}
  */
 
 /**
  * @defgroup lwip_opts_dhcpv6 DHCPv6
  * @ingroup lwip_opts_ipv6
  * @{
  */
 /**
  * LWIP_IPV6_DHCP6==1: enable DHCPv6 stateful/stateless address autoconfiguration.
  */
 #if !defined LWIP_IPV6_DHCP6 || defined __DOXYGEN__
 #define LWIP_IPV6_DHCP6                 0
 #endif
 
 /**
  * LWIP_IPV6_DHCP6_STATEFUL==1: enable DHCPv6 stateful address autoconfiguration.
  * (not supported, yet!)
  */
 #if !defined LWIP_IPV6_DHCP6_STATEFUL || defined __DOXYGEN__
 #define LWIP_IPV6_DHCP6_STATEFUL        0
 #endif
 
 /**
  * LWIP_IPV6_DHCP6_STATELESS==1: enable DHCPv6 stateless address autoconfiguration.
  */
 #if !defined LWIP_IPV6_DHCP6_STATELESS || defined __DOXYGEN__
 #define LWIP_IPV6_DHCP6_STATELESS       LWIP_IPV6_DHCP6
 #endif
 
 /**
  * LWIP_DHCP6_GETS_NTP==1: Request NTP servers via DHCPv6. For each
  * response packet, a callback is called, which has to be provided by the port:
  * void dhcp6_set_ntp_servers(u8_t num_ntp_servers, ip_addr_t* ntp_server_addrs);
 */
 #if !defined LWIP_DHCP6_GET_NTP_SRV || defined __DOXYGEN__
 #define LWIP_DHCP6_GET_NTP_SRV          0
 #endif
 
 /**
  * The maximum of NTP servers requested
  */
 #if !defined LWIP_DHCP6_MAX_NTP_SERVERS || defined __DOXYGEN__
 #define LWIP_DHCP6_MAX_NTP_SERVERS      1
 #endif
 
 /**
  * LWIP_DHCP6_MAX_DNS_SERVERS > 0: Request DNS servers via DHCPv6.
  * DNS servers received in the response are passed to DNS via @ref dns_setserver()
  * (up to the maximum limit defined here).
  */
 #if !defined LWIP_DHCP6_MAX_DNS_SERVERS || defined __DOXYGEN__
 #define LWIP_DHCP6_MAX_DNS_SERVERS      DNS_MAX_SERVERS
 #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:\code{.c}
  * 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);
  * \endcode
  * - 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_TCP_INPACKET_PCB:
  * Hook for intercepting incoming packets before they are passed to a pcb. This
  * allows updating some state or even dropping a packet.
  * Signature:\code{.c}
  * err_t my_hook_tcp_inpkt(struct tcp_pcb *pcb, struct tcp_hdr *hdr, u16_t optlen, u16_t opt1len, u8_t *opt2, struct pbuf *p);
  * \endcode
  * Arguments:
  * - pcb: tcp_pcb selected for input of this packet (ATTENTION: this may be
  *        struct tcp_pcb_listen if pcb->state == LISTEN)
  * - hdr: pointer to tcp header (ATTENTION: tcp options may not be in one piece!)
  * - optlen: tcp option length
  * - opt1len: tcp option length 1st part
  * - opt2: if this is != NULL, tcp options are split among 2 pbufs. In that case,
  *         options start at right after the tcp header ('(u8_t*)(hdr + 1)') for
  *         the first 'opt1len' bytes and the rest starts at 'opt2'. opt2len can
  *         be simply calculated: 'opt2len = optlen - opt1len;'
  * - p: input packet, p->payload points to application data (that's why tcp hdr
  *      and options are passed in seperately)
  * Return value:
  * - ERR_OK: continue input of this packet as normal
  * - != ERR_OK: drop this packet for input (don't continue input processing)
  *
  * ATTENTION: don't call any tcp api functions that might change tcp state (pcb
  * state or any pcb lists) from this callback!
  */
 #ifdef __DOXYGEN__
 #define LWIP_HOOK_TCP_INPACKET_PCB(pcb, hdr, optlen, opt1len, opt2, p)
 #endif
 
 /**
  * LWIP_HOOK_TCP_OUT_TCPOPT_LENGTH:
  * Hook for increasing the size of the options allocated with a tcp header.
  * Together with LWIP_HOOK_TCP_OUT_ADD_TCPOPTS, this can be used to add custom
  * options to outgoing tcp segments.
  * Signature:\code{.c}
  * u8_t my_hook_tcp_out_tcpopt_length(const struct tcp_pcb *pcb, u8_t internal_option_length);
  * \endcode
  * Arguments:
  * - pcb: tcp_pcb that transmits (ATTENTION: this may be NULL or
  *        struct tcp_pcb_listen if pcb->state == LISTEN)
  * - internal_option_length: tcp option length used by the stack internally
  * Return value:
  * - a number of bytes to allocate for tcp options (internal_option_length <= ret <= 40)
  *
  * ATTENTION: don't call any tcp api functions that might change tcp state (pcb
  * state or any pcb lists) from this callback!
  */
 #ifdef __DOXYGEN__
 #define LWIP_HOOK_TCP_OUT_TCPOPT_LENGTH(pcb, internal_len)
 #endif
 
 /**
  * LWIP_HOOK_TCP_OUT_ADD_TCPOPTS:
  * Hook for adding custom options to outgoing tcp segments.
  * Space for these custom options has to be reserved via LWIP_HOOK_TCP_OUT_TCPOPT_LENGTH.
  * Signature:\code{.c}
  * u32_t *my_hook_tcp_out_add_tcpopts(struct pbuf *p, struct tcp_hdr *hdr, const struct tcp_pcb *pcb, u32_t *opts);
  * \endcode
  * Arguments:
  * - p: output packet, p->payload pointing to tcp header, data follows
  * - hdr: tcp header
  * - pcb: tcp_pcb that transmits (ATTENTION: this may be NULL or
  *        struct tcp_pcb_listen if pcb->state == LISTEN)
  * - opts: pointer where to add the custom options (there may already be options
  *         between the header and these)
  * Return value:
  * - pointer pointing directly after the inserted options
  *
  * ATTENTION: don't call any tcp api functions that might change tcp state (pcb
  * state or any pcb lists) from this callback!
  */
 #ifdef __DOXYGEN__
 #define LWIP_HOOK_TCP_OUT_ADD_TCPOPTS(p, hdr, pcb, opts)
 #endif
 
 /**
  * LWIP_HOOK_IP4_INPUT(pbuf, input_netif):
  * Called from ip_input() (IPv4)
  * Signature:\code{.c}
  *   int my_hook(struct pbuf *pbuf, struct netif *input_netif);
  * \endcode
  * Arguments:
  * - 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)
  * Signature:\code{.c}
  *   struct netif *my_hook(const ip4_addr_t *dest);
  * \endcode
  * Arguments:
  * - dest: destination IPv4 address
  * Returns values:
  * - the destination netif
  * - 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(src, dest):
  * Source-based routing for IPv4 - called from ip_route() (IPv4)
  * Signature:\code{.c}
  *   struct netif *my_hook(const ip4_addr_t *src, const ip4_addr_t *dest);
  * \endcode
  * Arguments:
  * - src: local/source IPv4 address
  * - dest: destination IPv4 address
  * Returns values:
  * - the destination netif
  * - NULL if no destination netif is found. In that case, ip_route() continues as normal.
  */
 #ifdef __DOXYGEN__
 #define LWIP_HOOK_IP4_ROUTE_SRC(src, dest)
 #endif
 
 /**
  * LWIP_HOOK_IP4_CANFORWARD(src, dest):
  * Check if an IPv4 can be forwarded - called from:
  * ip4_input() -> ip4_forward() -> ip4_canforward() (IPv4)
  * - source address is available via ip4_current_src_addr()
  * - calling an output function in this context (e.g. multicast router) is allowed
  * Signature:\code{.c}
  *   int my_hook(struct pbuf *p, u32_t dest_addr_hostorder);
  * \endcode
  * Arguments:
  * - p: packet to forward
  * - dest: destination IPv4 address
  * Returns values:
  * - 1: forward
  * - 0: don't forward
  * - -1: no decision. In that case, ip4_canforward() continues as normal.
  */
 #ifdef __DOXYGEN__
 #define LWIP_HOOK_IP4_CANFORWARD(src, dest)
 #endif
 
 /**
  * LWIP_HOOK_ETHARP_GET_GW(netif, dest):
  * Called from etharp_output() (IPv4)
  * Signature:\code{.c}
  *   const ip4_addr_t *my_hook(struct netif *netif, const ip4_addr_t *dest);
  * \endcode
  * Arguments:
  * - netif: the netif used for sending
  * - dest: the destination IPv4 address
  * Return values:
  * - the IPv4 address of the gateway to handle the specified destination IPv4 address
  * - NULL, in which case 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)
  * Signature:\code{.c}
  *   int my_hook(struct pbuf *pbuf, struct netif *input_netif);
  * \endcode
  * Arguments:
  * - 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 ip_route() (IPv6)
  * Signature:\code{.c}
  *   struct netif *my_hook(const ip6_addr_t *dest, const ip6_addr_t *src);
  * \endcode
  * Arguments:
  * - src: source IPv6 address
  * - dest: destination IPv6 address
  * Return values:
  * - the destination netif
  * - 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)
  * Signature:\code{.c}
  *   const ip6_addr_t *my_hook(struct netif *netif, const ip6_addr_t *dest);
  * \endcode
  * Arguments:
  * - netif: the netif used for sending
  * - dest: the destination IPv6 address
  * Return values:
  * - the IPv6 address of the next hop to handle the specified destination IPv6 address
  * - NULL, in which case 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
  * Signature:\code{.c}
  *   int my_hook(struct netif *netif, struct eth_hdr *eth_hdr, struct eth_vlan_hdr *vlan_hdr);
  * \endcode
  * Arguments:
  * - 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:\code{.c}
  *   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
  * \endcode
  * 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
  * Signature:\code{.c}
  *   void my_hook(memp_t type);
  * \endcode
  */
 #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.
  * Signature:\code{.c}
  *   err_t my_hook(struct pbuf* pbuf, struct netif* netif);
  * \endcode
  * Arguments:
  * - p: rx packet with unknown eth type
  * - netif: netif on which the packet has been received
  * Return values:
  * - ERR_OK if packet is accepted (hook function now owns the pbuf)
  * - any error code otherwise (pbuf is freed)
  *
  * Payload points to ethernet header!
  */
 #ifdef __DOXYGEN__
 #define LWIP_HOOK_UNKNOWN_ETH_PROTOCOL(pbuf, netif)
 #endif
 
 /**
  * LWIP_HOOK_DHCP_APPEND_OPTIONS(netif, dhcp, state, msg, msg_type, options_len_ptr):
  * Called from various dhcp functions when sending a DHCP message.
  * This hook is called just before the DHCP message trailer is added, so the
  * options are at the end of a DHCP message.
  * Signature:\code{.c}
  *   void my_hook(struct netif *netif, struct dhcp *dhcp, u8_t state, struct dhcp_msg *msg,
  *                u8_t msg_type, u16_t *options_len_ptr);
  * \endcode
  * Arguments:
  * - netif: struct netif that the packet will be sent through
  * - dhcp: struct dhcp on that netif
  * - state: current dhcp state (dhcp_state_enum_t as an u8_t)
  * - msg: struct dhcp_msg that will be sent
  * - msg_type: dhcp message type to be sent (u8_t)
  * - options_len_ptr: pointer to the current length of options in the dhcp_msg "msg"
  *                    (must be increased when options are added!)
  *
  * Options need to appended like this:
  *   LWIP_ASSERT("dhcp option overflow", *options_len_ptr + option_len + 2 <= DHCP_OPTIONS_LEN);
  *   msg->options[(*options_len_ptr)++] = &lt;option_number&gt;;
  *   msg->options[(*options_len_ptr)++] = &lt;option_len&gt;;
  *   msg->options[(*options_len_ptr)++] = &lt;option_bytes&gt;;
  *   [...]
  */
 #ifdef __DOXYGEN__
 #define LWIP_HOOK_DHCP_APPEND_OPTIONS(netif, dhcp, state, msg, msg_type, options_len_ptr)
 #endif
 
 /**
  * LWIP_HOOK_DHCP_PARSE_OPTION(netif, dhcp, state, msg, msg_type, option, len, pbuf, option_value_offset):
  * Called from dhcp_parse_reply when receiving a DHCP message.
  * This hook is called for every option in the received message that is not handled internally.
  * Signature:\code{.c}
  *   void my_hook(struct netif *netif, struct dhcp *dhcp, u8_t state, struct dhcp_msg *msg,
  *                u8_t msg_type, u8_t option, u8_t option_len, struct pbuf *pbuf, u16_t option_value_offset);
  * \endcode
  * Arguments:
  * - netif: struct netif that the packet will be sent through
  * - dhcp: struct dhcp on that netif
  * - state: current dhcp state (dhcp_state_enum_t as an u8_t)
  * - msg: struct dhcp_msg that was received
  * - msg_type: dhcp message type received (u8_t, ATTENTION: only valid after
  *             the message type option has been parsed!)
  * - option: option value (u8_t)
  * - len: option data length (u8_t)
  * - pbuf: pbuf where option data is contained
  * - option_value_offset: offset in pbuf where option data begins
  *
  * A nice way to get the option contents is pbuf_get_contiguous():
  *  u8_t buf[32];
  *  u8_t *ptr = (u8_t*)pbuf_get_contiguous(p, buf, sizeof(buf), LWIP_MIN(option_len, sizeof(buf)), offset);
  */
 #ifdef __DOXYGEN__
 #define LWIP_HOOK_DHCP_PARSE_OPTION(netif, dhcp, state, msg, msg_type, option, len, pbuf, offset)
 #endif
 
 /**
  * LWIP_HOOK_DHCP6_APPEND_OPTIONS(netif, dhcp6, state, msg, msg_type, options_len_ptr, max_len):
  * Called from various dhcp6 functions when sending a DHCP6 message.
  * This hook is called just before the DHCP6 message is sent, so the
  * options are at the end of a DHCP6 message.
  * Signature:\code{.c}
  *   void my_hook(struct netif *netif, struct dhcp6 *dhcp, u8_t state, struct dhcp6_msg *msg,
  *                u8_t msg_type, u16_t *options_len_ptr);
  * \endcode
  * Arguments:
  * - netif: struct netif that the packet will be sent through
  * - dhcp6: struct dhcp6 on that netif
  * - state: current dhcp6 state (dhcp6_state_enum_t as an u8_t)
  * - msg: struct dhcp6_msg that will be sent
  * - msg_type: dhcp6 message type to be sent (u8_t)
  * - options_len_ptr: pointer to the current length of options in the dhcp6_msg "msg"
  *                    (must be increased when options are added!)
  *
  * Options need to appended like this:
  *   u8_t *options = (u8_t *)(msg + 1);
  *   LWIP_ASSERT("dhcp option overflow", sizeof(struct dhcp6_msg) + *options_len_ptr + newoptlen <= max_len);
  *   options[(*options_len_ptr)++] = &lt;option_data&gt;;
  *   [...]
  */
 #ifdef __DOXYGEN__
 #define LWIP_HOOK_DHCP6_APPEND_OPTIONS(netif, dhcp6, state, msg, msg_type, options_len_ptr, max_len)
 #endif
 
 /**
  * LWIP_HOOK_SOCKETS_SETSOCKOPT(s, sock, level, optname, optval, optlen, err)
  * Called from socket API to implement setsockopt() for options not provided by lwIP.
  * Core lock is held when this hook is called.
  * Signature:\code{.c}
  *   int my_hook(int s, struct lwip_sock *sock, int level, int optname, const void *optval, socklen_t optlen, int *err)
  * \endcode
  * Arguments:
  * - s: socket file descriptor
  * - sock: internal socket descriptor (see lwip/priv/sockets_priv.h)
  * - level: protocol level at which the option resides
  * - optname: option to set
  * - optval: value to set
  * - optlen: size of optval
  * - err: output error
  * Return values:
  * - 0: Hook has not consumed the option, code continues as normal (to internal options)
  * - != 0: Hook has consumed the option, 'err' is returned
  */
 #ifdef __DOXYGEN__
 #define LWIP_HOOK_SOCKETS_SETSOCKOPT(s, sock, level, optname, optval, optlen, err)
 #endif
 
 /**
  * LWIP_HOOK_SOCKETS_GETSOCKOPT(s, sock, level, optname, optval, optlen, err)
  * Called from socket API to implement getsockopt() for options not provided by lwIP.
  * Core lock is held when this hook is called.
  * Signature:\code{.c}
  *   int my_hook(int s, struct lwip_sock *sock, int level, int optname, void *optval, socklen_t *optlen, int *err)
  * \endcode
  * Arguments:
  * - s: socket file descriptor
  * - sock: internal socket descriptor (see lwip/priv/sockets_priv.h)
  * - level: protocol level at which the option resides
  * - optname: option to get
  * - optval: value to get
  * - optlen: size of optval
  * - err: output error
  * Return values:
  * - 0: Hook has not consumed the option, code continues as normal (to internal options)
  * - != 0: Hook has consumed the option, 'err' is returned
  */
 #ifdef __DOXYGEN__
 #define LWIP_HOOK_SOCKETS_GETSOCKOPT(s, sock, level, optname, optval, optlen, err)
 #endif
 
 /**
  * LWIP_HOOK_NETCONN_EXTERNAL_RESOLVE(name, addr, addrtype, err)
  * Called from netconn APIs (not usable with callback apps) allowing an
  * external DNS resolver (which uses sequential API) to handle the query.
  * Signature:\code{.c}
  *   int my_hook(const char *name, ip_addr_t *addr, u8_t addrtype, err_t *err)
  * \endcode
  * Arguments:
  * - name: hostname to resolve
  * - addr: output host address
  * - addrtype: type of address to query
  * - err: output error
  * Return values:
  * - 0: Hook has not consumed hostname query, query continues into DNS module
  * - != 0: Hook has consumed the query
  *
  * err must also be checked to determine if the hook consumed the query, but
  * the query failed
  */
 #ifdef __DOXYGEN__
 #define LWIP_HOOK_NETCONN_EXTERNAL_RESOLVE(name, addr, addrtype, err)
 #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
 
 /**
  * DHCP6_DEBUG: Enable debugging in dhcp6.c.
  */
 #if !defined DHCP6_DEBUG || defined __DOXYGEN__
 #define DHCP6_DEBUG                     LWIP_DBG_OFF
 #endif
 /**
  * @}
  */
 
 /**
  * LWIP_TESTMODE: Changes to make unit test possible
  */
 #if !defined LWIP_TESTMODE
 #define LWIP_TESTMODE                   0
 #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 */
Important Information for this Arm website
