lwipopts.h

/*
 * 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>
 *
 */

/**
 * @file
 *
 * lwIP Options Configuration
 */

/*
 * NOTE: || defined __DOXYGEN__ is a workaround for doxygen bug -
 * without this, doxygen does not see the actual #define
 */

#ifndef _LWIPOPTS_H_
#define _LWIPOPTS_H_

/*------------------------------------------------------------------------------
------------------------------- Config for libzt -------------------------------
------------------------------------------------------------------------------*/

// Misc
#define LWIP_STATS_LARGE                1
#define LWIP_NOASSERT                   1
#if __ANDROID__
#define LWIP_DONT_PROVIDE_BYTEORDER_FUNCTIONS 0
#endif
#if __ANDROID__
//#define LWIP_PROVIDE_ERRNO              0
#define SOCKLEN_T_DEFINED
#elif !defined(_MSC_VER)
#define LWIP_PROVIDE_ERRNO              1
#endif
// Sockets
#define LWIP_SOCKET                     1
#define LWIP_COMPAT_SOCKETS             0
#define LWIP_POSIX_SOCKETS_IO_NAMES     0
#define LWIP_SO_SNDTIMEO                1
#define LWIP_SO_RCVTIMEO                1
#define LWIP_SO_RCVBUF                  1
#define LWIP_SO_LINGER                  1
#define SO_REUSE                        1
#define LWIP_FIONREAD_LINUXMODE         1
// TCP
#define LWIP_TCP_KEEPALIVE              1
#define TCP_LISTEN_BACKLOG              1
// netif
#define LWIP_NETIF_STATUS_CALLBACK      0
#define LWIP_NETIF_EXT_STATUS_CALLBACK  0
#define LWIP_NETIF_LINK_CALLBACK        0
#define LWIP_NETIF_REMOVE_CALLBACK      0

/*------------------------------------------------------------------------------
------------------------------------ Presets -----------------------------------
------------------------------------------------------------------------------*/

#define LWIP_MTU                        2800
#define LWIP_CHKSUM_ALGORITHM           2
// memory
#define MEMP_NUM_NETCONN                1024
#define MEMP_NUM_NETBUF                 2
#define MEMP_NUM_TCPIP_MSG_API          1024
#define MEMP_NUM_TCPIP_MSG_INPKT        1024
#define PBUF_POOL_SIZE                  1024
#define TCP_DEFAULT_LISTEN_BACKLOG      0xff
// arp
#define ARP_TABLE_SIZE                  64
#define ARP_MAXAGE                      300
#define ARP_QUEUEING                    1
#define ARP_QUEUE_LEN                   3
// ip
#define IP_REASS_MAXAGE                 15
#define IP_REASS_MAX_PBUFS              32
// tcp
#define TCP_TMR_INTERVAL                250
#define TCP_WND                         0xffff0
#define TCP_MAXRTX                      12
#define TCP_SYNMAXRTX                   12
#define LWIP_TCP_SACK_OUT               1
#define LWIP_TCP_MAX_SACK_NUM           4
#define TCP_MSS                         (LWIP_MTU - 40)
#define TCP_SND_BUF                     (64 * TCP_MSS)
#define TCP_SND_QUEUELEN                (64 * (2 * (TCP_SND_BUF/TCP_MSS)))
#define TCP_SNDLOWAT                    (0xffff - (4*TCP_MSS) - 1)
#define TCP_SNDQUEUELOWAT               LWIP_MAX(((TCP_SND_QUEUELEN)/2), 5)
#define TCP_WND_UPDATE_THRESHOLD        LWIP_MIN((TCP_WND / 4), (TCP_MSS * 4))
#define LWIP_WND_SCALE                  1
#define TCP_RCV_SCALE                   4
// tcpip
#define TCPIP_MBOX_SIZE                 0
#define LWIP_TCPIP_CORE_LOCKING         1
#define LWIP_TCPIP_CORE_LOCKING_INPUT   1
// netconn
#define LWIP_NETCONN_FULLDUPLEX         0
// netif
#define LWIP_SINGLE_NETIF               0
#define LWIP_NETIF_HWADDRHINT           1
#define LWIP_NETIF_TX_SINGLE_PBUF       0
#define TCPIP_THREAD_PRIO               1

/*------------------------------------------------------------------------------
------------------------------------ Timers ------------------------------------
------------------------------------------------------------------------------*/
/*
Be careful about setting this too small.  lwIP just counts the number
of times its timer is called and uses this to control time sensitive
operations (such as TCP retransmissions), rather than actually
measuring time using something more accurate.  If you call the timer
functions very frequently you may see things (such as retransmissions)
happening sooner than they should.
*/
/* these are originally defined in tcp_impl.h */
#ifndef TCP_TMR_INTERVAL
/* The TCP timer interval in milliseconds. */
#define TCP_TMR_INTERVAL       25
#endif /* TCP_TMR_INTERVAL */

#ifndef TCP_FAST_INTERVAL
/* the fine grained timeout in milliseconds */
#define TCP_FAST_INTERVAL      TCP_TMR_INTERVAL
#endif /* TCP_FAST_INTERVAL */

#ifndef TCP_SLOW_INTERVAL
/* the coarse grained timeout in milliseconds */
#define TCP_SLOW_INTERVAL      (2*TCP_TMR_INTERVAL)
#endif /* TCP_SLOW_INTERVAL */

/*------------------------------------------------------------------------------
----------------------- Below: Modified contents of opt.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                 1
#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                 1
#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                   4
#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                        1024 * 1024 * 32
#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                   1024
#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                1024
#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                1024
#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                1024
#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         1024
#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                1024
#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              1024
#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 + PPP_NUM_TIMEOUTS + (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                1024
#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          64
#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        64
#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                  128
#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                  64
#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                    1
#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              32
#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                        1
#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                         (1 * 0xffff) // *1024 //0xFFFF // (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                   12 // 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               1
#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                         (MTU - 40)
#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                     (32 * 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                (64 * (2 * (TCP_SND_BUF/TCP_MSS))) // 1024 // ((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                    (0xffff - (4*TCP_MSS) - 1)
//#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              1
#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        (TCP_MSS)
#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                  1
#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                  1
#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      1
#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  1
#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        1
#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      1
#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           1
#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               "tcpip_thread"
#endif

/**
 * TCPIP_THREAD_STACKSIZE: The stack size used by the main tcpip thread.
 * The stack size value itself is platform-dependent, but is passed to
 * sys_thread_new() when the thread is created.
 */
#if !defined TCPIP_THREAD_STACKSIZE || defined __DOXYGEN__
#define TCPIP_THREAD_STACKSIZE          0
#endif

/**
 * TCPIP_THREAD_PRIO: The priority assigned to the main tcpip thread.
 * The priority value itself is platform-dependent, but is passed to
 * sys_thread_new() when the thread is created.
 */
#if !defined TCPIP_THREAD_PRIO || defined __DOXYGEN__
#define TCPIP_THREAD_PRIO               1
#endif

/**
 * TCPIP_MBOX_SIZE: The mailbox size for the tcpip thread messages
 * The queue size value itself is platform-dependent, but is passed to
 * sys_mbox_new() when tcpip_init is called.
 */
#if !defined TCPIP_MBOX_SIZE || defined __DOXYGEN__
#define TCPIP_MBOX_SIZE                 0
#endif

/**
 * Define this to something that triggers a watchdog. This is called from
 * tcpip_thread after processing a message.
 */
#if !defined LWIP_TCPIP_THREAD_ALIVE || defined __DOXYGEN__
#define LWIP_TCPIP_THREAD_ALIVE()
#endif

/**
 * SLIPIF_THREAD_NAME: The name assigned to the slipif_loop thread.
 */
#if !defined SLIPIF_THREAD_NAME || defined __DOXYGEN__
#define SLIPIF_THREAD_NAME              "slipif_loop"
#endif

/**
 * SLIP_THREAD_STACKSIZE: The stack size used by the slipif_loop thread.
 * The stack size value itself is platform-dependent, but is passed to
 * sys_thread_new() when the thread is created.
 */
#if !defined SLIPIF_THREAD_STACKSIZE || defined __DOXYGEN__
#define SLIPIF_THREAD_STACKSIZE         0
#endif

/**
 * SLIPIF_THREAD_PRIO: The priority assigned to the slipif_loop thread.
 * The priority value itself is platform-dependent, but is passed to
 * sys_thread_new() when the thread is created.
 */
#if !defined SLIPIF_THREAD_PRIO || defined __DOXYGEN__
#define SLIPIF_THREAD_PRIO              1
#endif

/**
 * DEFAULT_THREAD_NAME: The name assigned to any other lwIP thread.
 */
#if !defined DEFAULT_THREAD_NAME || defined __DOXYGEN__
#define DEFAULT_THREAD_NAME             "lwIP"
#endif

/**
 * DEFAULT_THREAD_STACKSIZE: The stack size used by any other lwIP thread.
 * The stack size value itself is platform-dependent, but is passed to
 * sys_thread_new() when the thread is created.
 */
#if !defined DEFAULT_THREAD_STACKSIZE || defined __DOXYGEN__
#define DEFAULT_THREAD_STACKSIZE        0
#endif

/**
 * DEFAULT_THREAD_PRIO: The priority assigned to any other lwIP thread.
 * The priority value itself is platform-dependent, but is passed to
 * sys_thread_new() when the thread is created.
 */
#if !defined DEFAULT_THREAD_PRIO || defined __DOXYGEN__
#define DEFAULT_THREAD_PRIO             1
#endif

/**
 * DEFAULT_RAW_RECVMBOX_SIZE: The mailbox size for the incoming packets on a
 * NETCONN_RAW. The queue size value itself is platform-dependent, but is passed
 * to sys_mbox_new() when the recvmbox is created.
 */
#if !defined DEFAULT_RAW_RECVMBOX_SIZE || defined __DOXYGEN__
#define DEFAULT_RAW_RECVMBOX_SIZE       0
#endif

/**
 * DEFAULT_UDP_RECVMBOX_SIZE: The mailbox size for the incoming packets on a
 * NETCONN_UDP. The queue size value itself is platform-dependent, but is passed
 * to sys_mbox_new() when the recvmbox is created.
 */
#if !defined DEFAULT_UDP_RECVMBOX_SIZE || defined __DOXYGEN__
#define DEFAULT_UDP_RECVMBOX_SIZE       0
#endif

/**
 * DEFAULT_TCP_RECVMBOX_SIZE: The mailbox size for the incoming packets on a
 * NETCONN_TCP. The queue size value itself is platform-dependent, but is passed
 * to sys_mbox_new() when the recvmbox is created.
 */
#if !defined DEFAULT_TCP_RECVMBOX_SIZE || defined __DOXYGEN__
#define DEFAULT_TCP_RECVMBOX_SIZE       0
#endif

/**
 * DEFAULT_ACCEPTMBOX_SIZE: The mailbox size for the incoming connections.
 * The queue size value itself is platform-dependent, but is passed to
 * sys_mbox_new() when the acceptmbox is created.
 */
#if !defined DEFAULT_ACCEPTMBOX_SIZE || defined __DOXYGEN__
#define DEFAULT_ACCEPTMBOX_SIZE         0
#endif
/**
 * @}
 */

/*
   ----------------------------------------------
   ---------- Sequential layer options ----------
   ----------------------------------------------
*/
/**
 * @defgroup lwip_opts_netconn Netconn
 * @ingroup lwip_opts_threadsafe_apis
 * @{
 */
/**
 * LWIP_NETCONN==1: Enable Netconn API (require to use api_lib.c)
 */
#if !defined LWIP_NETCONN || defined __DOXYGEN__
#define LWIP_NETCONN                    1
#endif

/** LWIP_TCPIP_TIMEOUT==1: Enable tcpip_timeout/tcpip_untimeout to create
 * timers running in tcpip_thread from another thread.
 */
#if !defined LWIP_TCPIP_TIMEOUT || defined __DOXYGEN__
#define LWIP_TCPIP_TIMEOUT              0
#endif

/** LWIP_NETCONN_SEM_PER_THREAD==1: Use one (thread-local) semaphore per
 * thread calling socket/netconn functions instead of allocating one
 * semaphore per netconn (and per select etc.)
 * ATTENTION: a thread-local semaphore for API calls is needed:
 * - LWIP_NETCONN_THREAD_SEM_GET() returning a sys_sem_t*
 * - LWIP_NETCONN_THREAD_SEM_ALLOC() creating the semaphore
 * - LWIP_NETCONN_THREAD_SEM_FREE() freeing the semaphore
 * The latter 2 can be invoked up by calling netconn_thread_init()/netconn_thread_cleanup().
 * Ports may call these for threads created with sys_thread_new().
 */
#if !defined LWIP_NETCONN_SEM_PER_THREAD || defined __DOXYGEN__
#define LWIP_NETCONN_SEM_PER_THREAD     0
#endif

/** LWIP_NETCONN_FULLDUPLEX==1: Enable code that allows reading from one thread,
 * writing from a 2nd thread and closing from a 3rd thread at the same time.
 * ATTENTION: This is currently really alpha! Some requirements:
 * - LWIP_NETCONN_SEM_PER_THREAD==1 is required to use one socket/netconn from
 *   multiple threads at once
 * - sys_mbox_free() has to unblock receive tasks waiting on recvmbox/acceptmbox
 *   and prevent a task pending on this during/after deletion
 */
#if !defined LWIP_NETCONN_FULLDUPLEX || defined __DOXYGEN__
#define LWIP_NETCONN_FULLDUPLEX         0
#endif
/**
 * @}
 */

/*
   ------------------------------------
   ---------- Socket options ----------
   ------------------------------------
*/
/**
 * @defgroup lwip_opts_socket Sockets
 * @ingroup lwip_opts_threadsafe_apis
 * @{
 */
/**
 * LWIP_SOCKET==1: Enable Socket API (require to use sockets.c)
 */
#if !defined LWIP_SOCKET || defined __DOXYGEN__
#define LWIP_SOCKET                     1
#endif

/**
 * LWIP_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             0
#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     0
#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              1
#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                1
#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                1
#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                  1
#endif

/**
 * LWIP_SO_LINGER==1: Enable SO_LINGER processing.
 */
#if !defined LWIP_SO_LINGER || defined __DOXYGEN__
#define LWIP_SO_LINGER                  1
#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                        1
#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         1
#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
/**
 * @}
 */

/*
   --------------------------------------
   ---------- 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               0
#endif

/**
 * CHECKSUM_CHECK_UDP==1: Check checksums in software for incoming UDP packets.
 */
#if !defined CHECKSUM_CHECK_UDP || defined __DOXYGEN__
#define CHECKSUM_CHECK_UDP              0
#endif

/**
 * CHECKSUM_CHECK_TCP==1: Check checksums in software for incoming TCP packets.
 */
#if !defined CHECKSUM_CHECK_TCP || defined __DOXYGEN__
#define CHECKSUM_CHECK_TCP              0
#endif

/**
 * CHECKSUM_CHECK_ICMP==1: Check checksums in software for incoming ICMP packets.
 */
#if !defined CHECKSUM_CHECK_ICMP || defined __DOXYGEN__
#define CHECKSUM_CHECK_ICMP             0
#endif

/**
 * CHECKSUM_CHECK_ICMP6==1: Check checksums in software for incoming ICMPv6 packets
 */
#if !defined CHECKSUM_CHECK_ICMP6 || defined __DOXYGEN__
#define CHECKSUM_CHECK_ICMP6            0
#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                       1
#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                (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_OFF
#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 */