#ifndef __LWIP_OPT_H__#define __LWIP_OPT_H__/* Include user defined options first */#include "lwipopts.h"#include "lwip/debug.h"/* Define default values for unconfigured parameters. *//* Platform specific locking *//* * enable SYS_LIGHTWEIGHT_PROT in lwipopts.h if you want inter-task protection * for certain critical regions during buffer allocation, deallocation and memory * allocation and deallocation. */#ifndef SYS_LIGHTWEIGHT_PROT#define SYS_LIGHTWEIGHT_PROT            0#endif#ifndef NO_SYS#define NO_SYS                          0#endif/* ---------- Memory options ---------- *//* MEM_ALIGNMENT: should be set to the alignment of the CPU for which   lwIP is compiled. 4 byte alignment -> define MEM_ALIGNMENT to 4, 2   byte alignment -> define MEM_ALIGNMENT to 2. */#ifndef MEM_ALIGNMENT#define MEM_ALIGNMENT                   1#endif/* MEM_SIZE: the size of the heap memory. If the application will senda lot of data that needs to be copied, this should be set high. */#ifndef MEM_SIZE#define MEM_SIZE                        1600#endif#ifndef MEMP_SANITY_CHECK#define MEMP_SANITY_CHECK       1#endif/* MEMP_NUM_PBUF: the number of memp struct pbufs. If the application   sends a lot of data out of ROM (or other static memory), this   should be set high. */#ifndef MEMP_NUM_PBUF#define MEMP_NUM_PBUF                   16#endif/* Number of raw connection PCBs */#ifndef MEMP_NUM_RAW_PCB#define MEMP_NUM_RAW_PCB                4#endif/* MEMP_NUM_UDP_PCB: the number of UDP protocol control blocks. One   per active UDP "connection". */#ifndef MEMP_NUM_UDP_PCB#define MEMP_NUM_UDP_PCB                4#endif/* MEMP_NUM_TCP_PCB: the number of simulatenously active TCP   connections. */#ifndef MEMP_NUM_TCP_PCB#define MEMP_NUM_TCP_PCB                5#endif/* MEMP_NUM_TCP_PCB_LISTEN: the number of listening TCP   connections. */#ifndef MEMP_NUM_TCP_PCB_LISTEN#define MEMP_NUM_TCP_PCB_LISTEN         8#endif/* MEMP_NUM_TCP_SEG: the number of simultaneously queued TCP   segments. */#ifndef MEMP_NUM_TCP_SEG#define MEMP_NUM_TCP_SEG                16#endif/* MEMP_NUM_SYS_TIMEOUT: the number of simulateously active   timeouts. */#ifndef MEMP_NUM_SYS_TIMEOUT#define MEMP_NUM_SYS_TIMEOUT            3#endif/* The following four are used only with the sequential API and can be   set to 0 if the application only will use the raw API. *//* MEMP_NUM_NETBUF: the number of struct netbufs. */#ifndef MEMP_NUM_NETBUF#define MEMP_NUM_NETBUF                 2#endif/* MEMP_NUM_NETCONN: the number of struct netconns. */#ifndef MEMP_NUM_NETCONN#define MEMP_NUM_NETCONN                4#endif/* MEMP_NUM_APIMSG: the number of struct api_msg, used for   communication between the TCP/IP stack and the sequential   programs. */#ifndef MEMP_NUM_API_MSG#define MEMP_NUM_API_MSG                8#endif/* MEMP_NUM_TCPIPMSG: the number of struct tcpip_msg, which is used   for sequential API communication and incoming packets. Used in   src/api/tcpip.c. */#ifndef MEMP_NUM_TCPIP_MSG#define MEMP_NUM_TCPIP_MSG              8#endif/* ---------- Pbuf options ---------- *//* PBUF_POOL_SIZE: the number of buffers in the pbuf pool. */#ifndef PBUF_POOL_SIZE#define PBUF_POOL_SIZE                  16#endif/* PBUF_POOL_BUFSIZE: the size of each pbuf in the pbuf pool. */#ifndef PBUF_POOL_BUFSIZE#define PBUF_POOL_BUFSIZE               128#endif/* PBUF_LINK_HLEN: the number of bytes that should be allocated for a   link level header. Defaults to 14 for Ethernet. */#ifndef PBUF_LINK_HLEN#define PBUF_LINK_HLEN                  14#endif/* ---------- ARP options ---------- *//** Number of active hardware address, IP address pairs cached */#ifndef ARP_TABLE_SIZE#define ARP_TABLE_SIZE                  10#endif/** * If enabled, outgoing packets are queued during hardware address * resolution. * * This feature has not stabilized yet. Single-packet queueing is * believed to be stable, multi-packet queueing is believed to * clash with the TCP segment queueing. *  * As multi-packet-queueing is currently disabled, enabling this * _should_ work, but we need your testing feedback on lwip-users. * */#ifndef ARP_QUEUEING#define ARP_QUEUEING                    1#endif/* This option is deprecated */#ifdef ETHARP_QUEUE_FIRST#error ETHARP_QUEUE_FIRST option is deprecated. Remove it from your lwipopts.h.#endif/* This option is removed to comply with the ARP standard */#ifdef ETHARP_ALWAYS_INSERT#error ETHARP_ALWAYS_INSERT option is deprecated. Remove it from your lwipopts.h.#endif/* ---------- IP options ---------- *//* Define IP_FORWARD to 1 if you wish to have 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. */#ifndef IP_FORWARD#define IP_FORWARD                      0#endif/* If defined to 1, IP options are allowed (but not parsed). If   defined to 0, all packets with IP options are dropped. */#ifndef IP_OPTIONS#define IP_OPTIONS                      1#endif/** IP reassembly and segmentation. Even if they both deal with IP *  fragments, note that these are orthogonal（正交）, one dealing with incoming *  packets, the other with outgoing packets *//** Reassemble incoming fragmented IP packets */#ifndef IP_REASSEMBLY#define IP_REASSEMBLY                   1#endif/** Fragment outgoing IP packets if their size exceeds MTU */#ifndef IP_FRAG#define IP_FRAG                         1#endif/* ---------- ICMP options ---------- */#ifndef ICMP_TTL#define ICMP_TTL                        255#endif/* ---------- RAW options ---------- */#ifndef LWIP_RAW#define LWIP_RAW                        1#endif#ifndef RAW_TTL#define RAW_TTL                        255#endif/* ---------- DHCP options ---------- */#ifndef LWIP_DHCP#define LWIP_DHCP                       0#endif/*  if you want to do an ARP check on the offered address   (recommended推薦). */#ifndef DHCP_DOES_ARP_CHECK#define DHCP_DOES_ARP_CHECK             1#endif/* ---------- UDP options ---------- */#ifndef LWIP_UDP#define LWIP_UDP                        1#endif#ifndef UDP_TTL#define UDP_TTL                         255#endif/* ---------- TCP options ---------- */#ifndef LWIP_TCP#define LWIP_TCP                        1#endif#ifndef TCP_TTL#define TCP_TTL                         255#endif#ifndef TCP_WND#define TCP_WND                         2048#endif #ifndef TCP_MAXRTX#define TCP_MAXRTX                      12#endif#ifndef TCP_SYNMAXRTX#define TCP_SYNMAXRTX                   6#endif/* Controls if TCP should queue segments that arrive out of   order. Define to 0 if your device is low on memory. */#ifndef TCP_QUEUE_OOSEQ#define TCP_QUEUE_OOSEQ                 1#endif/* TCP Maximum segment size. */#ifndef TCP_MSS#define TCP_MSS                         128 /* A *very* conservative default. */#endif/* TCP sender buffer space (bytes). */#ifndef TCP_SND_BUF#define TCP_SND_BUF                     256#endif/* TCP sender buffer space (pbufs). This must be at least = 2 *   TCP_SND_BUF/TCP_MSS for things to work. */#ifndef TCP_SND_QUEUELEN#define TCP_SND_QUEUELEN                4 * TCP_SND_BUF/TCP_MSS#endif/* Maximum number of retransmissions of data segments. *//* Maximum number of retransmissions of SYN segments. *//* TCP writable space (bytes). This must be less than or equal   to TCP_SND_BUF. It is the amount of space which must be   available in the tcp snd_buf for select to return writable */#ifndef TCP_SNDLOWAT#define TCP_SNDLOWAT                    TCP_SND_BUF/2#endif/* Support loop interface (127.0.0.1) */#ifndef LWIP_HAVE_LOOPIF#define LWIP_HAVE_LOOPIF                0  #endif#ifndef LWIP_EVENT_API#define LWIP_EVENT_API                  0#define LWIP_CALLBACK_API               1#else #define LWIP_EVENT_API                  1#define LWIP_CALLBACK_API               0#endif #ifndef LWIP_COMPAT_SOCKETS#define LWIP_COMPAT_SOCKETS             1#endif#ifndef TCPECHO_THREAD_PRIO#define TCPECHO_THREAD_PRIO               1#endif#ifndef UDPECHO_THREAD_PRIO#define UDPECHO_THREAD_PRIO               1#endif#ifndef TCPIP_THREAD_PRIO#define TCPIP_THREAD_PRIO               1#endif#ifndef SLIPIF_THREAD_PRIO#define SLIPIF_THREAD_PRIO              1#endif#ifndef PPP_THREAD_PRIO#define PPP_THREAD_PRIO                 1#endif#ifndef DEFAULT_THREAD_PRIO#define DEFAULT_THREAD_PRIO             1#endif/* ---------- Socket Options ---------- *//* Enable SO_REUSEADDR and SO_REUSEPORT options */ #ifdef SO_REUSE/* I removed the lot since this was an ugly hack. It broke the raw-API.   It also came with many ugly goto's, Christiaan Simons.   處理器命令#error強迫編譯程序停止編譯，主要用于程序調試。 */#error SO_REUSE currently unavailable, this was a hack#endif                                                                        /* ---------- Statistics options ---------- */#ifndef LWIP_STATS#define LWIP_STATS                      0#endif#if LWIP_STATS#ifndef LWIP_STATS_DISPLAY#define LWIP_STATS_DISPLAY 0#endif#ifndef LINK_STATS