Quest Cross Reference 0.1.0/​kernel/​include/​lwip/​opt.h	Source navigation Diff markup Identifier search General search
	Version: 0.1.0 experimental Revert   Change

Warning, cross-references for /kernel/include/lwip/opt.h need to be fixed.

 /**
  * @file
  *
  * lwIP Options Configuration
  */
 
 /*
  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
  * All rights reserved. 
  * 
  * Redistribution and use in source and binary forms, with or without modification, 
  * are permitted provided that the following conditions are met:
  *
  * 1. Redistributions of source code must retain the above copyright notice,
  *    this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright notice,
  *    this list of conditions and the following disclaimer in the documentation
  *    and/or other materials provided with the distribution.
  * 3. The name of the author may not be used to endorse or promote products
  *    derived from this software without specific prior written permission. 
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
  * OF SUCH DAMAGE.
  *
  * This file is part of the lwIP TCP/IP stack.
  * 
  * Author: Adam Dunkels <adam@sics.se>
  *
  */
 #ifndef __LWIP_OPT_H__
 #define __LWIP_OPT_H__
 
 /*
  * Include user defined options first. Anything not defined in these files
  * will be set to standard values. Override anything you dont like!
  */
 #include "lwipopts.h"
 #include "lwip/debug.h"
 
 /*
    -----------------------------------------------
    ---------- Platform specific locking ----------
    -----------------------------------------------
 */
 
 /**
  * SYS_LIGHTWEIGHT_PROT==1: 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
 
 /** 
  * NO_SYS==1: Provides VERY minimal functionality. Otherwise,
  * use lwIP facilities.
  */
 #ifndef NO_SYS
 #define NO_SYS                          0
 #endif
 
 /**
  * MEMCPY: override this if you have a faster implementation at hand than the
  * one included in your C library
  */
 #ifndef MEMCPY
 #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.
  */
 #ifndef SMEMCPY
 #define SMEMCPY(dst,src,len)            memcpy(dst,src,len)
 #endif
 
 /*
    ------------------------------------
    ---------- Memory options ----------
    ------------------------------------
 */
 /**
  * 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.
  */
 #ifndef MEM_LIBC_MALLOC
 #define MEM_LIBC_MALLOC                 0
 #endif
 
 /**
 * MEMP_MEM_MALLOC==1: Use mem_malloc/mem_free instead of the lwip pool allocator.
 * Especially useful with MEM_LIBC_MALLOC but handle with care regarding execution
 * speed and usage from interrupts!
 */
 #ifndef MEMP_MEM_MALLOC
 #define MEMP_MEM_MALLOC                 0
 #endif
 
 /**
  * MEM_ALIGNMENT: should be set to the alignment of the CPU
  *    4 byte alignment -> #define MEM_ALIGNMENT 4
  *    2 byte alignment -> #define MEM_ALIGNMENT 2
  */
 #ifndef MEM_ALIGNMENT
 #define MEM_ALIGNMENT                   1
 #endif
 
 /**
  * MEM_SIZE: the size of the heap memory. If the application will send
  * a lot of data that needs to be copied, this should be set high.
  */
 #ifndef MEM_SIZE
 #define MEM_SIZE                        1600
 #endif
 
 /**
  * MEMP_OVERFLOW_CHECK: memp overflow protection reserves a configurable
  * amount of bytes before and after each memp element in every pool and fills
  * it with a prominent default value.
  *    MEMP_OVERFLOW_CHECK == 0 no checking
  *    MEMP_OVERFLOW_CHECK == 1 checks each element when it is freed
  *    MEMP_OVERFLOW_CHECK >= 2 checks each element in every pool every time
  *      memp_malloc() or memp_free() is called (useful but slow!)
  */
 #ifndef MEMP_OVERFLOW_CHECK
 #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.
  */
 #ifndef MEMP_SANITY_CHECK
 #define MEMP_SANITY_CHECK               0
 #endif
 
 /**
  * MEM_USE_POOLS==1: Use an alternative to malloc() by allocating from a set
  * of memory pools of various sizes. When mem_malloc is called, an element of
  * the smallest pool that can provide the length needed is returned.
  * To use this, MEMP_USE_CUSTOM_POOLS also has to be enabled.
  */
 #ifndef MEM_USE_POOLS
 #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. */
 #ifndef MEM_USE_POOLS_TRY_BIGGER_POOL
 #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 
  * inlude path somewhere. 
  */
 #ifndef MEMP_USE_CUSTOM_POOLS
 #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);
  */
 #ifndef LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT
 #define LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT 0
 #endif
 
 /*
    ------------------------------------------------
    ---------- Internal Memory Pool Sizes ----------
    ------------------------------------------------
 */
 /**
  * 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.
  */
 #ifndef MEMP_NUM_PBUF
 #define MEMP_NUM_PBUF                   16
 #endif
 
 /**
  * MEMP_NUM_RAW_PCB: Number of raw connection PCBs
  * (requires the LWIP_RAW option)
  */
 #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".
  * (requires the LWIP_UDP option)
  */
 #ifndef MEMP_NUM_UDP_PCB
 #define MEMP_NUM_UDP_PCB                4
 #endif
 
 /**
  * MEMP_NUM_TCP_PCB: the number of simulatenously active TCP connections.
  * (requires the LWIP_TCP option)
  */
 #ifndef MEMP_NUM_TCP_PCB
 #define MEMP_NUM_TCP_PCB                5
 #endif
 
 /**
  * MEMP_NUM_TCP_PCB_LISTEN: the number of listening TCP connections.
  * (requires the LWIP_TCP option)
  */
 #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.
  * (requires the LWIP_TCP option)
  */
 #ifndef MEMP_NUM_TCP_SEG
 #define MEMP_NUM_TCP_SEG                16
 #endif
 
 /**
  * MEMP_NUM_REASSDATA: the number of simultaneously IP packets queued for
  * reassembly (whole packets, not fragments!)
  */
 #ifndef MEMP_NUM_REASSDATA
 #define MEMP_NUM_REASSDATA              5
 #endif
 
 /**
  * MEMP_NUM_ARP_QUEUE: the number of simulateously queued outgoing
  * packets (pbufs) that are waiting for an ARP request (to resolve
  * their destination address) to finish.
  * (requires the ARP_QUEUEING option)
  */
 #ifndef MEMP_NUM_ARP_QUEUE
 #define MEMP_NUM_ARP_QUEUE              30
 #endif
 
 /**
  * MEMP_NUM_IGMP_GROUP: The number of multicast groups whose network interfaces
  * can be members et the same time (one per netif - allsystems group -, plus one
  * per netif membership).
  * (requires the LWIP_IGMP option)
  */
 #ifndef MEMP_NUM_IGMP_GROUP
 #define MEMP_NUM_IGMP_GROUP             8
 #endif
 
 /**
  * MEMP_NUM_SYS_TIMEOUT: the number of simulateously active timeouts.
  * (requires NO_SYS==0)
  */
 #ifndef MEMP_NUM_SYS_TIMEOUT
 #define MEMP_NUM_SYS_TIMEOUT            3
 #endif
 
 /**
  * MEMP_NUM_NETBUF: the number of struct netbufs.
  * (only needed if you use the sequential API, like api_lib.c)
  */
 #ifndef MEMP_NUM_NETBUF
 #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)
  */
 #ifndef MEMP_NUM_NETCONN
 #define MEMP_NUM_NETCONN                4
 #endif
 
 /**
  * MEMP_NUM_TCPIP_MSG_API: the number of struct tcpip_msg, which are used
  * for callback/timeout API communication. 
  * (only needed if you use tcpip.c)
  */
 #ifndef MEMP_NUM_TCPIP_MSG_API
 #define MEMP_NUM_TCPIP_MSG_API          8
 #endif
 
 /**
  * MEMP_NUM_TCPIP_MSG_INPKT: the number of struct tcpip_msg, which are used
  * for incoming packets. 
  * (only needed if you use tcpip.c)
  */
 #ifndef MEMP_NUM_TCPIP_MSG_INPKT
 #define MEMP_NUM_TCPIP_MSG_INPKT        8
 #endif
 
 /**
  * PBUF_POOL_SIZE: the number of buffers in the pbuf pool. 
  */
 #ifndef PBUF_POOL_SIZE
 #define PBUF_POOL_SIZE                  16
 #endif
 
 /*
    ---------------------------------
    ---------- ARP options ----------
    ---------------------------------
 */
 /**
  * LWIP_ARP==1: Enable ARP functionality.
  */
 #ifndef LWIP_ARP
 #define LWIP_ARP                        1
 #endif
 
 /**
  * ARP_TABLE_SIZE: Number of active MAC-IP address pairs cached.
  */
 #ifndef ARP_TABLE_SIZE
 #define ARP_TABLE_SIZE                  10
 #endif
 
 /**
  * ARP_QUEUEING==1: Outgoing packets are queued during hardware address
  * resolution.
  */
 #ifndef ARP_QUEUEING
 #define ARP_QUEUEING                    1
 #endif
 
 /**
  * ETHARP_TRUST_IP_MAC==1: Incoming IP packets cause the ARP table to be
  * updated with the source MAC and IP addresses supplied in the packet.
  * You may want to disable this if you do not trust LAN peers to have the
  * correct addresses, or as a limited approach to attempt to handle
  * spoofing. If disabled, lwIP will need to make a new ARP request if
  * the peer is not already in the ARP table, adding a little latency.
  */
 #ifndef ETHARP_TRUST_IP_MAC
 #define ETHARP_TRUST_IP_MAC             1
 #endif
 
 /**
  * ETHARP_SUPPORT_VLAN==1: support receiving ethernet packets with VLAN header.
  * 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.
  */
 #ifndef ETHARP_SUPPORT_VLAN
 #define ETHARP_SUPPORT_VLAN             0
 #endif
 
 /*
    --------------------------------
    ---------- IP options ----------
    --------------------------------
 */
 /**
  * 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.
  */
 #ifndef IP_FORWARD
 #define IP_FORWARD                      0
 #endif
 
 /**
  * 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).
  */
 #ifndef IP_OPTIONS_ALLOWED
 #define IP_OPTIONS_ALLOWED              1
 #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.
  */
 #ifndef IP_REASSEMBLY
 #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.
  */
 #ifndef IP_FRAG
 #define IP_FRAG                         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.
  */
 #ifndef IP_REASS_MAXAGE
 #define IP_REASS_MAXAGE                 3
 #endif
 
 /**
  * IP_REASS_MAX_PBUFS: Total maximum amount of pbufs waiting to be reassembled.
  * Since the received pbufs are enqueued, be sure to configure
  * PBUF_POOL_SIZE > IP_REASS_MAX_PBUFS so that the stack is still able to receive
  * packets even if the maximum amount of fragments is enqueued for reassembly!
  */
 #ifndef IP_REASS_MAX_PBUFS
 #define IP_REASS_MAX_PBUFS              10
 #endif
 
 /**
  * IP_FRAG_USES_STATIC_BUF==1: Use a static MTU-sized buffer for IP
  * fragmentation. Otherwise pbufs are allocated and reference the original
  * packet data to be fragmented.
  */
 #ifndef IP_FRAG_USES_STATIC_BUF
 #define IP_FRAG_USES_STATIC_BUF         1
 #endif
 
 /**
  * IP_FRAG_MAX_MTU: Assumed max MTU on any interface for IP frag buffer
  * (requires IP_FRAG_USES_STATIC_BUF==1)
  */
 #if IP_FRAG_USES_STATIC_BUF && !defined(IP_FRAG_MAX_MTU)
 #define IP_FRAG_MAX_MTU                 1500
 #endif
 
 /**
  * IP_DEFAULT_TTL: Default value for Time-To-Live used by transport layers.
  */
 #ifndef IP_DEFAULT_TTL
 #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.
  */
 #ifndef IP_SOF_BROADCAST
 #define IP_SOF_BROADCAST                0
 #endif
 
 /**
  * IP_SOF_BROADCAST_RECV (requires IP_SOF_BROADCAST=1) enable the broadcast
  * filter on recv operations.
  */
 #ifndef IP_SOF_BROADCAST_RECV
 #define IP_SOF_BROADCAST_RECV           0
 #endif
 
 /*
    ----------------------------------
    ---------- ICMP options ----------
    ----------------------------------
 */
 /**
  * LWIP_ICMP==1: Enable ICMP module inside the IP stack.
  * Be careful, disable that make your product non-compliant to RFC1122
  */
 #ifndef LWIP_ICMP
 #define LWIP_ICMP                       1
 #endif
 
 /**
  * ICMP_TTL: Default value for Time-To-Live used by ICMP packets.
  */
 #ifndef ICMP_TTL
 #define ICMP_TTL                       (IP_DEFAULT_TTL)
 #endif
 
 /**
  * LWIP_BROADCAST_PING==1: respond to broadcast pings (default is unicast only)
  */
 #ifndef LWIP_BROADCAST_PING
 #define LWIP_BROADCAST_PING             0
 #endif
 
 /**
  * LWIP_MULTICAST_PING==1: respond to multicast pings (default is unicast only)
  */
 #ifndef LWIP_MULTICAST_PING
 #define LWIP_MULTICAST_PING             0
 #endif
 
 /*
    ---------------------------------
    ---------- RAW options ----------
    ---------------------------------
 */
 /**
  * LWIP_RAW==1: Enable application layer to hook into the IP layer itself.
  */
 #ifndef LWIP_RAW
 #define LWIP_RAW                        1
 #endif
 
 /**
  * LWIP_RAW==1: Enable application layer to hook into the IP layer itself.
  */
 #ifndef RAW_TTL
 #define RAW_TTL                        (IP_DEFAULT_TTL)
 #endif
 
 /*
    ----------------------------------
    ---------- DHCP options ----------
    ----------------------------------
 */
 /**
  * LWIP_DHCP==1: Enable DHCP module.
  */
 #ifndef LWIP_DHCP
 #define LWIP_DHCP                       0
 #endif
 
 /**
  * DHCP_DOES_ARP_CHECK==1: Do an ARP check on the offered address.
  */
 #ifndef DHCP_DOES_ARP_CHECK
 #define DHCP_DOES_ARP_CHECK             ((LWIP_DHCP) && (LWIP_ARP))
 #endif
 
 /*
    ------------------------------------
    ---------- AUTOIP options ----------
    ------------------------------------
 */
 /**
  * LWIP_AUTOIP==1: Enable AUTOIP module.
  */
 #ifndef LWIP_AUTOIP
 #define LWIP_AUTOIP                     0
 #endif
 
 /**
  * LWIP_DHCP_AUTOIP_COOP==1: Allow DHCP and AUTOIP to be both enabled on
  * the same interface at the same time.
  */
 #ifndef LWIP_DHCP_AUTOIP_COOP
 #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. 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.
  */
 #ifndef LWIP_DHCP_AUTOIP_COOP_TRIES
 #define LWIP_DHCP_AUTOIP_COOP_TRIES     9
 #endif
 
 /*
    ----------------------------------
    ---------- SNMP options ----------
    ----------------------------------
 */
 /**
  * LWIP_SNMP==1: Turn on SNMP module. UDP must be available for SNMP
  * transport.
  */
 #ifndef LWIP_SNMP
 #define LWIP_SNMP                       0
 #endif
 
 /**
  * SNMP_CONCURRENT_REQUESTS: Number of concurrent requests the module will
  * allow. At least one request buffer is required. 
  */
 #ifndef SNMP_CONCURRENT_REQUESTS
 #define SNMP_CONCURRENT_REQUESTS        1
 #endif
 
 /**
  * SNMP_TRAP_DESTINATIONS: Number of trap destinations. At least one trap
  * destination is required
  */
 #ifndef SNMP_TRAP_DESTINATIONS
 #define SNMP_TRAP_DESTINATIONS          1
 #endif
 
 /**
  * SNMP_PRIVATE_MIB: 
  */
 #ifndef SNMP_PRIVATE_MIB
 #define SNMP_PRIVATE_MIB                0
 #endif
 
 /**
  * Only allow SNMP write actions that are 'safe' (e.g. disabeling netifs is not
  * a safe action and disabled when SNMP_SAFE_REQUESTS = 1).
  * Unsafe requests are disabled by default!
  */
 #ifndef SNMP_SAFE_REQUESTS
 #define SNMP_SAFE_REQUESTS              1
 #endif
 
 /*
    ----------------------------------
    ---------- IGMP options ----------
    ----------------------------------
 */
 /**
  * LWIP_IGMP==1: Turn on IGMP module. 
  */
 #ifndef LWIP_IGMP
 #define LWIP_IGMP                       0
 #endif
 
 /*
    ----------------------------------
    ---------- DNS options -----------
    ----------------------------------
 */
 /**
  * LWIP_DNS==1: Turn on DNS module. UDP must be available for DNS
  * transport.
  */
 #ifndef LWIP_DNS
 #define LWIP_DNS                        0
 #endif
 
 /** DNS maximum number of entries to maintain locally. */
 #ifndef DNS_TABLE_SIZE
 #define DNS_TABLE_SIZE                  4
 #endif
 
 /** DNS maximum host name length supported in the name table. */
 #ifndef DNS_MAX_NAME_LENGTH
 #define DNS_MAX_NAME_LENGTH             256
 #endif
 
 /** The maximum of DNS servers */
 #ifndef DNS_MAX_SERVERS
 #define DNS_MAX_SERVERS                 2
 #endif
 
 /** DNS do a name checking between the query and the response. */
 #ifndef DNS_DOES_NAME_CHECK
 #define DNS_DOES_NAME_CHECK             1
 #endif
 
 /** DNS use a local buffer if DNS_USES_STATIC_BUF=0, a static one if
     DNS_USES_STATIC_BUF=1, or a dynamic one if DNS_USES_STATIC_BUF=2.
     The buffer will be of size DNS_MSG_SIZE */
 #ifndef DNS_USES_STATIC_BUF
 #define DNS_USES_STATIC_BUF             1
 #endif
 
 /** DNS message max. size. Default value is RFC compliant. */
 #ifndef DNS_MSG_SIZE
 #define DNS_MSG_SIZE                    512
 #endif
 
 /** DNS_LOCAL_HOSTLIST: Implements a local host-to-address list. If enabled,
  *  you have to define
  *    #define DNS_LOCAL_HOSTLIST_INIT {{"host1", 0x123}, {"host2", 0x234}}
  *  (an array of structs name/address, where address is an u32_t in network
  *  byte order).
  *
  *  Instead, you can also use an external function:
  *  #define DNS_LOOKUP_LOCAL_EXTERN(x) extern u32_t my_lookup_function(const char *name)
  *  that returns the IP address or INADDR_NONE if not found.
  */
 #ifndef DNS_LOCAL_HOSTLIST
 #define DNS_LOCAL_HOSTLIST              0
 #endif /* DNS_LOCAL_HOSTLIST */
 
 /** If this is turned on, the local host-list can be dynamically changed
  *  at runtime. */
 #ifndef DNS_LOCAL_HOSTLIST_IS_DYNAMIC
 #define DNS_LOCAL_HOSTLIST_IS_DYNAMIC   0
 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
 
 /*
    ---------------------------------
    ---------- UDP options ----------
    ---------------------------------
 */
 /**
  * LWIP_UDP==1: Turn on UDP.
  */
 #ifndef LWIP_UDP
 #define LWIP_UDP                        1
 #endif
 
 /**
  * LWIP_UDPLITE==1: Turn on UDP-Lite. (Requires LWIP_UDP)
  */
 #ifndef LWIP_UDPLITE
 #define LWIP_UDPLITE                    0
 #endif
 
 /**
  * UDP_TTL: Default Time-To-Live value.
  */
 #ifndef UDP_TTL
 #define UDP_TTL                         (IP_DEFAULT_TTL)
 #endif
 
 /**
  * LWIP_NETBUF_RECVINFO==1: append destination addr and port to every netbuf.
  */
 #ifndef LWIP_NETBUF_RECVINFO
 #define LWIP_NETBUF_RECVINFO            0
 #endif
 
 /*
    ---------------------------------
    ---------- TCP options ----------
    ---------------------------------
 */
 /**
  * LWIP_TCP==1: Turn on TCP.
  */
 #ifndef LWIP_TCP
 #define LWIP_TCP                        1
 #endif
 
 /**
  * TCP_TTL: Default Time-To-Live value.
  */
 #ifndef TCP_TTL
 #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
  */
 #ifndef TCP_WND
 #define TCP_WND                         (4 * TCP_MSS)
 #endif 
 
 /**
  * TCP_MAXRTX: Maximum number of retransmissions of data segments.
  */
 #ifndef TCP_MAXRTX
 #define TCP_MAXRTX                      12
 #endif
 
 /**
  * TCP_SYNMAXRTX: Maximum number of retransmissions of SYN segments.
  */
 #ifndef TCP_SYNMAXRTX
 #define TCP_SYNMAXRTX                   6
 #endif
 
 /**
  * TCP_QUEUE_OOSEQ==1: TCP will queue segments that arrive out of order.
  * Define to 0 if your device is low on memory.
  */
 #ifndef TCP_QUEUE_OOSEQ
 #define TCP_QUEUE_OOSEQ                 (LWIP_TCP)
 #endif
 
 /**
  * TCP_MSS: TCP Maximum segment size. (default is 536, a conservative default,
  * you might want to increase this.)
  * For the receive side, this MSS is advertised to the remote side
  * when opening a connection. For the transmit size, this MSS sets
  * an upper limit on the MSS advertised by the remote host.
  */
 #ifndef TCP_MSS
 #define TCP_MSS                         536
 #endif
 
 /**
  * TCP_CALCULATE_EFF_SEND_MSS: "The maximum size of a segment that TCP really
  * sends, the 'effective send MSS,' MUST be the smaller of the send MSS (which
  * reflects the available reassembly buffer size at the remote host) and the
  * largest size permitted by the IP layer" (RFC 1122)
  * Setting this to 1 enables code that checks TCP_MSS against the MTU of the
  * netif used for a connection and limits the MSS if it would be too big otherwise.
  */
 #ifndef TCP_CALCULATE_EFF_SEND_MSS
 #define TCP_CALCULATE_EFF_SEND_MSS      1
 #endif
 
 
 /**
  * TCP_SND_BUF: TCP sender buffer space (bytes). 
  */
 #ifndef TCP_SND_BUF
 #define TCP_SND_BUF                     256
 #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.
  */
 #ifndef TCP_SND_QUEUELEN
 #define TCP_SND_QUEUELEN                (4 * (TCP_SND_BUF)/(TCP_MSS))
 #endif
 
 /**
  * TCP_SNDLOWAT: 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
 
 /**
  * TCP_LISTEN_BACKLOG: Enable the backlog option for tcp listen pcb.
  */
 #ifndef TCP_LISTEN_BACKLOG
 #define TCP_LISTEN_BACKLOG              0
 #endif
 
 /**
  * The maximum allowed backlog for TCP listen netconns.
  * This backlog is used unless another is explicitly specified.
  * 0xff is the maximum (u8_t).
  */
 #ifndef TCP_DEFAULT_LISTEN_BACKLOG
 #define TCP_DEFAULT_LISTEN_BACKLOG      0xff
 #endif
 
 /**
  * LWIP_TCP_TIMESTAMPS==1: support the TCP timestamp option.
  */
 #ifndef LWIP_TCP_TIMESTAMPS
 #define LWIP_TCP_TIMESTAMPS             0
 #endif
 
 /**
  * TCP_WND_UPDATE_THRESHOLD: difference in window to trigger an
  * explicit window update
  */
 #ifndef TCP_WND_UPDATE_THRESHOLD
 #define TCP_WND_UPDATE_THRESHOLD   (TCP_WND / 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.
  */
 #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
 
 
 /*
    ----------------------------------
    ---------- Pbuf options ----------
    ----------------------------------
 */
 /**
  * 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.
  */
 #ifndef PBUF_LINK_HLEN
 #define PBUF_LINK_HLEN                  14
 #endif
 
 /**
  * PBUF_POOL_BUFSIZE: the size of each pbuf in the pbuf pool. The default is
  * designed to accomodate single full size TCP frame in one pbuf, including
  * TCP_MSS, IP header, and link header.
  */
 #ifndef PBUF_POOL_BUFSIZE
 #define PBUF_POOL_BUFSIZE               LWIP_MEM_ALIGN_SIZE(TCP_MSS+40+PBUF_LINK_HLEN)
 #endif
 
 /*
    ------------------------------------------------
    ---------- Network Interfaces options ----------
    ------------------------------------------------
 */
 /**
  * LWIP_NETIF_HOSTNAME==1: use DHCP_OPTION_HOSTNAME with netif's hostname
  * field.
  */
 #ifndef LWIP_NETIF_HOSTNAME
 #define LWIP_NETIF_HOSTNAME             0
 #endif
 
 /**
  * LWIP_NETIF_API==1: Support netif api (in netifapi.c)
  */
 #ifndef LWIP_NETIF_API
 #define LWIP_NETIF_API                  0
 #endif
 
 /**
  * LWIP_NETIF_STATUS_CALLBACK==1: Support a callback function whenever an interface
  * changes its up/down status (i.e., due to DHCP IP acquistion)
  */
 #ifndef LWIP_NETIF_STATUS_CALLBACK
 #define LWIP_NETIF_STATUS_CALLBACK      0
 #endif
 
 /**
  * LWIP_NETIF_LINK_CALLBACK==1: Support a callback function from an interface
  * whenever the link changes (i.e., link down)
  */
 #ifndef LWIP_NETIF_LINK_CALLBACK
 #define LWIP_NETIF_LINK_CALLBACK        0
 #endif
 
 /**
  * LWIP_NETIF_HWADDRHINT==1: Cache link-layer-address hints (e.g. table
  * indices) in struct netif. TCP and UDP can make use of this to prevent
  * scanning the ARP table for every sent packet. While this is faster for big
  * ARP tables or many concurrent connections, it might be counterproductive
  * if you have a tiny ARP table or if there never are concurrent connections.
  */
 #ifndef LWIP_NETIF_HWADDRHINT
 #define LWIP_NETIF_HWADDRHINT           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.
  */
 #ifndef LWIP_NETIF_LOOPBACK
 #define LWIP_NETIF_LOOPBACK             0
 #endif
 
 /**
  * LWIP_LOOPBACK_MAX_PBUFS: Maximum number of pbufs on queue for loopback
  * sending for each netif (0 = disabled)
  */
 #ifndef LWIP_LOOPBACK_MAX_PBUFS
 #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.
  */
 #ifndef LWIP_NETIF_LOOPBACK_MULTITHREADING
 #define LWIP_NETIF_LOOPBACK_MULTITHREADING    (!NO_SYS)
 #endif
 
 /**
  * LWIP_NETIF_TX_SINGLE_PBUF: if this is set to 1, lwIP tries to put all data
  * to be sent into one single pbuf. This is for compatibility with DMA-enabled
  * MACs that do not support scatter-gather.
  * Beware that this might involve CPU-memcpy before transmitting that would not
  * be needed without this flag! Use this only if you need to!
  *
  * @todo: TCP and IP-frag do not work with this, yet:
  */
 #ifndef LWIP_NETIF_TX_SINGLE_PBUF
 #define LWIP_NETIF_TX_SINGLE_PBUF             0
 #endif /* LWIP_NETIF_TX_SINGLE_PBUF */
 
 /*
    ------------------------------------
    ---------- LOOPIF options ----------
    ------------------------------------
 */
 /**
  * LWIP_HAVE_LOOPIF==1: Support loop interface (127.0.0.1) and loopif.c
  */
 #ifndef LWIP_HAVE_LOOPIF
 #define LWIP_HAVE_LOOPIF                0
 #endif
 
 /*
    ------------------------------------
    ---------- SLIPIF options ----------
    ------------------------------------
 */
 /**
  * LWIP_HAVE_SLIPIF==1: Support slip interface and slipif.c
  */
 #ifndef LWIP_HAVE_SLIPIF
 #define LWIP_HAVE_SLIPIF                0
 #endif
 
 /*
    ------------------------------------
    ---------- Thread options ----------
    ------------------------------------
 */
 /**
  * TCPIP_THREAD_NAME: The name assigned to the main tcpip thread.
  */
 #ifndef TCPIP_THREAD_NAME
 #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.
  */
 #ifndef TCPIP_THREAD_STACKSIZE
 #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.
  */
 #ifndef TCPIP_THREAD_PRIO
 #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.
  */
 #ifndef TCPIP_MBOX_SIZE
 #define TCPIP_MBOX_SIZE                 0
 #endif
 
 /**
  * SLIPIF_THREAD_NAME: The name assigned to the slipif_loop thread.
  */
 #ifndef SLIPIF_THREAD_NAME
 #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.
  */
 #ifndef SLIPIF_THREAD_STACKSIZE
 #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.
  */
 #ifndef SLIPIF_THREAD_PRIO
 #define SLIPIF_THREAD_PRIO              1
 #endif
 
 /**
  * PPP_THREAD_NAME: The name assigned to the pppMain thread.
  */
 #ifndef PPP_THREAD_NAME
 #define PPP_THREAD_NAME                "pppMain"
 #endif
 
 /**
  * PPP_THREAD_STACKSIZE: The stack size used by the pppMain thread.
  * The stack size value itself is platform-dependent, but is passed to
  * sys_thread_new() when the thread is created.
  */
 #ifndef PPP_THREAD_STACKSIZE
 #define PPP_THREAD_STACKSIZE            0
 #endif
 
 /**
  * PPP_THREAD_PRIO: The priority assigned to the pppMain thread.
  * The priority value itself is platform-dependent, but is passed to
  * sys_thread_new() when the thread is created.
  */
 #ifndef PPP_THREAD_PRIO
 #define PPP_THREAD_PRIO                 1
 #endif
 
 /**
  * DEFAULT_THREAD_NAME: The name assigned to any other lwIP thread.
  */
 #ifndef DEFAULT_THREAD_NAME
 #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.
  */
 #ifndef DEFAULT_THREAD_STACKSIZE
 #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.
  */
 #ifndef DEFAULT_THREAD_PRIO
 #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.
  */
 #ifndef DEFAULT_RAW_RECVMBOX_SIZE
 #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.
  */
 #ifndef DEFAULT_UDP_RECVMBOX_SIZE
 #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.
  */
 #ifndef DEFAULT_TCP_RECVMBOX_SIZE
 #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.
  */
 #ifndef DEFAULT_ACCEPTMBOX_SIZE
 #define DEFAULT_ACCEPTMBOX_SIZE         0
 #endif
 
 /*
    ----------------------------------------------
    ---------- Sequential layer options ----------
    ----------------------------------------------
 */
 /**
  * LWIP_TCPIP_CORE_LOCKING: (EXPERIMENTAL!)
  * Don't use it if you're not an active lwIP project member
  */
 #ifndef LWIP_TCPIP_CORE_LOCKING
 #define LWIP_TCPIP_CORE_LOCKING         0
 #endif
 
 /**
  * LWIP_NETCONN==1: Enable Netconn API (require to use api_lib.c)
  */
 #ifndef LWIP_NETCONN
 #define LWIP_NETCONN                    1
 #endif
 
 /*
    ------------------------------------
    ---------- Socket options ----------
    ------------------------------------
 */
 /**
  * LWIP_SOCKET==1: Enable Socket API (require to use sockets.c)
  */
 #ifndef LWIP_SOCKET
 #define LWIP_SOCKET                     1
 #endif
 
 /**
  * LWIP_COMPAT_SOCKETS==1: Enable BSD-style sockets functions names.
  * (only used if you use sockets.c)
  */
 #ifndef LWIP_COMPAT_SOCKETS
 #define LWIP_COMPAT_SOCKETS             1
 #endif
 
 /**
  * LWIP_POSIX_SOCKETS_IO_NAMES==1: Enable POSIX-style sockets functions names.
  * Disable this option if you use a POSIX operating system that uses the same
  * names (read, write & close). (only used if you use sockets.c)
  */
 #ifndef LWIP_POSIX_SOCKETS_IO_NAMES
 #define LWIP_POSIX_SOCKETS_IO_NAMES     1
 #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)
  */
 #ifndef LWIP_TCP_KEEPALIVE
 #define LWIP_TCP_KEEPALIVE              0
 #endif
 
 /**
  * LWIP_SO_RCVTIMEO==1: Enable SO_RCVTIMEO processing.
  */
 #ifndef LWIP_SO_RCVTIMEO
 #define LWIP_SO_RCVTIMEO                0
 #endif
 
 /**
  * LWIP_SO_RCVBUF==1: Enable SO_RCVBUF processing.
  */
 #ifndef LWIP_SO_RCVBUF
 #define LWIP_SO_RCVBUF                  0
 #endif
 
 /**
  * If LWIP_SO_RCVBUF is used, this is the default value for recv_bufsize.
  */
 #ifndef RECV_BUFSIZE_DEFAULT
 #define RECV_BUFSIZE_DEFAULT            INT_MAX
 #endif
 
 /**
  * SO_REUSE==1: Enable SO_REUSEADDR and SO_REUSEPORT options. DO NOT USE!
  */
 #ifndef SO_REUSE
 #define SO_REUSE                        0
 #endif
 
 /*
    ----------------------------------------
    ---------- Statistics options ----------
    ----------------------------------------
 */
 /**
  * LWIP_STATS==1: Enable statistics collection in lwip_stats.
  */
 #ifndef LWIP_STATS
 #define LWIP_STATS                      1
 #endif
 
 #if LWIP_STATS
 
 /**
  * LWIP_STATS_DISPLAY==1: Compile in the statistics output functions.
  */
 #ifndef LWIP_STATS_DISPLAY
 #define LWIP_STATS_DISPLAY              0
 #endif
 
 /**
  * LINK_STATS==1: Enable link stats.
  */
 #ifndef LINK_STATS
 #define LINK_STATS                      1
 #endif
 
 /**
  * ETHARP_STATS==1: Enable etharp stats.
  */
 #ifndef ETHARP_STATS
 #define ETHARP_STATS                    (LWIP_ARP)
 #endif
 
 /**
  * IP_STATS==1: Enable IP stats.
  */
 #ifndef IP_STATS
 #define IP_STATS                        1
 #endif
 
 /**
  * IPFRAG_STATS==1: Enable IP fragmentation stats. Default is
  * on if using either frag or reass.
  */
 #ifndef IPFRAG_STATS
 #define IPFRAG_STATS                    (IP_REASSEMBLY || IP_FRAG)
 #endif
 
 /**
  * ICMP_STATS==1: Enable ICMP stats.
  */
 #ifndef ICMP_STATS
 #define ICMP_STATS                      1
 #endif
 
 /**
  * IGMP_STATS==1: Enable IGMP stats.
  */
 #ifndef IGMP_STATS
 #define IGMP_STATS                      (LWIP_IGMP)
 #endif
 
 /**
  * UDP_STATS==1: Enable UDP stats. Default is on if
  * UDP enabled, otherwise off.
  */
 #ifndef UDP_STATS
 #define UDP_STATS                       (LWIP_UDP)
 #endif
 
 /**
  * TCP_STATS==1: Enable TCP stats. Default is on if TCP
  * enabled, otherwise off.
  */
 #ifndef TCP_STATS
 #define TCP_STATS                       (LWIP_TCP)
 #endif
 
 /**
  * MEM_STATS==1: Enable mem.c stats.
  */
 #ifndef MEM_STATS
 #define MEM_STATS                       ((MEM_LIBC_MALLOC == 0) && (MEM_USE_POOLS == 0))
 #endif
 
 /**
  * MEMP_STATS==1: Enable memp.c pool stats.
  */
 #ifndef MEMP_STATS
 #define MEMP_STATS                      (MEMP_MEM_MALLOC == 0)
 #endif
 
 /**
  * SYS_STATS==1: Enable system stats (sem and mbox counts, etc).
  */
 #ifndef SYS_STATS
 #define SYS_STATS                       (NO_SYS == 0)
 #endif
 
 #else
 
 #define LINK_STATS                      0
 #define IP_STATS                        0
 #define IPFRAG_STATS                    0
 #define ICMP_STATS                      0
 #define IGMP_STATS                      0
 #define UDP_STATS                       0
 #define TCP_STATS                       0
 #define MEM_STATS                       0
 #define MEMP_STATS                      0
 #define SYS_STATS                       0
 #define LWIP_STATS_DISPLAY              0
 
 #endif /* LWIP_STATS */
 
 /*
    ---------------------------------
    ---------- PPP options ----------
    ---------------------------------
 */
 /**
  * PPP_SUPPORT==1: Enable PPP.
  */
 #ifndef PPP_SUPPORT
 #define PPP_SUPPORT                     0
 #endif
 
 /**
  * PPPOE_SUPPORT==1: Enable PPP Over Ethernet
  */
 #ifndef PPPOE_SUPPORT
 #define PPPOE_SUPPORT                   0
 #endif
 
 /**
  * PPPOS_SUPPORT==1: Enable PPP Over Serial
  */
 #ifndef PPPOS_SUPPORT
 #define PPPOS_SUPPORT                   PPP_SUPPORT
 #endif
 
 #if PPP_SUPPORT
 
 /**
  * NUM_PPP: Max PPP sessions.
  */
 #ifndef NUM_PPP
 #define NUM_PPP                         1
 #endif
 
 /**
  * PAP_SUPPORT==1: Support PAP.
  */
 #ifndef PAP_SUPPORT
 #define PAP_SUPPORT                     0
 #endif
 
 /**
  * CHAP_SUPPORT==1: Support CHAP.
  */
 #ifndef CHAP_SUPPORT
 #define CHAP_SUPPORT                    0
 #endif
 
 /**
  * MSCHAP_SUPPORT==1: Support MSCHAP. CURRENTLY NOT SUPPORTED! DO NOT SET!
  */
 #ifndef MSCHAP_SUPPORT
 #define MSCHAP_SUPPORT                  0
 #endif
 
 /**
  * CBCP_SUPPORT==1: Support CBCP. CURRENTLY NOT SUPPORTED! DO NOT SET!
  */
 #ifndef CBCP_SUPPORT
 #define CBCP_SUPPORT                    0
 #endif
 
 /**
  * CCP_SUPPORT==1: Support CCP. CURRENTLY NOT SUPPORTED! DO NOT SET!
  */
 #ifndef CCP_SUPPORT
 #define CCP_SUPPORT                     0
 #endif
 
 /**
  * VJ_SUPPORT==1: Support VJ header compression.
  */
 #ifndef VJ_SUPPORT
 #define VJ_SUPPORT                      0
 #endif
 
 /**
  * MD5_SUPPORT==1: Support MD5 (see also CHAP).
  */
 #ifndef MD5_SUPPORT
 #define MD5_SUPPORT                     0
 #endif
 
 /*
  * Timeouts
  */
 #ifndef FSM_DEFTIMEOUT
 #define FSM_DEFTIMEOUT                  6       /* Timeout time in seconds */
 #endif
 
 #ifndef FSM_DEFMAXTERMREQS
 #define FSM_DEFMAXTERMREQS              2       /* Maximum Terminate-Request transmissions */
 #endif
 
 #ifndef FSM_DEFMAXCONFREQS
 #define FSM_DEFMAXCONFREQS              10      /* Maximum Configure-Request transmissions */
 #endif
 
 #ifndef FSM_DEFMAXNAKLOOPS
 #define FSM_DEFMAXNAKLOOPS              5       /* Maximum number of nak loops */
 #endif
 
 #ifndef UPAP_DEFTIMEOUT
 #define UPAP_DEFTIMEOUT                 6       /* Timeout (seconds) for retransmitting req */
 #endif
 
 #ifndef UPAP_DEFREQTIME
 #define UPAP_DEFREQTIME                 30      /* Time to wait for auth-req from peer */
 #endif
 
 #ifndef CHAP_DEFTIMEOUT
 #define CHAP_DEFTIMEOUT                 6       /* Timeout time in seconds */
 #endif
 
 #ifndef CHAP_DEFTRANSMITS
 #define CHAP_DEFTRANSMITS               10      /* max # times to send challenge */
 #endif
 
 /* Interval in seconds between keepalive echo requests, 0 to disable. */
 #ifndef LCP_ECHOINTERVAL
 #define LCP_ECHOINTERVAL                0
 #endif
 
 /* Number of unanswered echo requests before failure. */
 #ifndef LCP_MAXECHOFAILS
 #define LCP_MAXECHOFAILS                3
 #endif
 
 /* Max Xmit idle time (in jiffies) before resend flag char. */
 #ifndef PPP_MAXIDLEFLAG
 #define PPP_MAXIDLEFLAG                 100
 #endif
 
 /*
  * Packet sizes
  *
  * Note - lcp shouldn't be allowed to negotiate stuff outside these
  *    limits.  See lcp.h in the pppd directory.
  * (XXX - these constants should simply be shared by lcp.c instead
  *    of living in lcp.h)
  */
 #define PPP_MTU                         1500     /* Default MTU (size of Info field) */
 #ifndef PPP_MAXMTU
 /* #define PPP_MAXMTU  65535 - (PPP_HDRLEN + PPP_FCSLEN) */
 #define PPP_MAXMTU                      1500 /* Largest MTU we allow */
 #endif
 #define PPP_MINMTU                      64
 #define PPP_MRU                         1500     /* default MRU = max length of info field */
 #define PPP_MAXMRU                      1500     /* Largest MRU we allow */
 #ifndef PPP_DEFMRU
 #define PPP_DEFMRU                      296             /* Try for this */
 #endif
 #define PPP_MINMRU                      128             /* No MRUs below this */
 
 #ifndef MAXNAMELEN
 #define MAXNAMELEN                      256     /* max length of hostname or name for auth */
 #endif
 #ifndef MAXSECRETLEN
 #define MAXSECRETLEN                    256     /* max length of password or secret */
 #endif
 
 #endif /* PPP_SUPPORT */
 
 /*
    --------------------------------------
    ---------- Checksum options ----------
    --------------------------------------
 */
 /**
  * CHECKSUM_GEN_IP==1: Generate checksums in software for outgoing IP packets.
  */
 #ifndef CHECKSUM_GEN_IP
 #define CHECKSUM_GEN_IP                 1
 #endif
  
 /**
  * CHECKSUM_GEN_UDP==1: Generate checksums in software for outgoing UDP packets.
  */
 #ifndef CHECKSUM_GEN_UDP
 #define CHECKSUM_GEN_UDP                1
 #endif
  
 /**
  * CHECKSUM_GEN_TCP==1: Generate checksums in software for outgoing TCP packets.
  */
 #ifndef CHECKSUM_GEN_TCP
 #define CHECKSUM_GEN_TCP                1
 #endif
  
 /**
  * CHECKSUM_CHECK_IP==1: Check checksums in software for incoming IP packets.
  */
 #ifndef CHECKSUM_CHECK_IP
 #define CHECKSUM_CHECK_IP               1
 #endif
  
 /**
  * CHECKSUM_CHECK_UDP==1: Check checksums in software for incoming UDP packets.
  */
 #ifndef CHECKSUM_CHECK_UDP
 #define CHECKSUM_CHECK_UDP              1
 #endif
 
 /**
  * CHECKSUM_CHECK_TCP==1: Check checksums in software for incoming TCP packets.
  */
 #ifndef CHECKSUM_CHECK_TCP
 #define CHECKSUM_CHECK_TCP              1
 #endif
 
 /*
    ---------------------------------------
    ---------- Debugging options ----------
    ---------------------------------------
 */
 /**
  * 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.
  */
 #ifndef LWIP_DBG_MIN_LEVEL
 #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.
  */
 #ifndef LWIP_DBG_TYPES_ON
 #define LWIP_DBG_TYPES_ON               LWIP_DBG_ON
 #endif
 
 /**
  * ETHARP_DEBUG: Enable debugging in etharp.c.
  */
 #ifndef ETHARP_DEBUG
 #define ETHARP_DEBUG                    LWIP_DBG_OFF
 #endif
 
 /**
  * NETIF_DEBUG: Enable debugging in netif.c.
  */
 #ifndef NETIF_DEBUG
 #define NETIF_DEBUG                     LWIP_DBG_OFF
 #endif
 
 /**
  * PBUF_DEBUG: Enable debugging in pbuf.c.
  */
 #ifndef PBUF_DEBUG
 #define PBUF_DEBUG                      LWIP_DBG_OFF
 #endif
 
 /**
  * API_LIB_DEBUG: Enable debugging in api_lib.c.
  */
 #ifndef API_LIB_DEBUG
 #define API_LIB_DEBUG                   LWIP_DBG_OFF
 #endif
 
 /**
  * API_MSG_DEBUG: Enable debugging in api_msg.c.
  */
 #ifndef API_MSG_DEBUG
 #define API_MSG_DEBUG                   LWIP_DBG_OFF
 #endif
 
 /**
  * SOCKETS_DEBUG: Enable debugging in sockets.c.
  */
 #ifndef SOCKETS_DEBUG
 #define SOCKETS_DEBUG                   LWIP_DBG_OFF
 #endif
 
 /**
  * ICMP_DEBUG: Enable debugging in icmp.c.
  */
 #ifndef ICMP_DEBUG
 #define ICMP_DEBUG                      LWIP_DBG_OFF
 #endif
 
 /**
  * IGMP_DEBUG: Enable debugging in igmp.c.
  */
 #ifndef IGMP_DEBUG
 #define IGMP_DEBUG                      LWIP_DBG_OFF
 #endif
 
 /**
  * INET_DEBUG: Enable debugging in inet.c.
  */
 #ifndef INET_DEBUG
 #define INET_DEBUG                      LWIP_DBG_OFF
 #endif
 
 /**
  * IP_DEBUG: Enable debugging for IP.
  */
 #ifndef IP_DEBUG
 #define IP_DEBUG                        LWIP_DBG_OFF
 #endif
 
 /**
  * IP_REASS_DEBUG: Enable debugging in ip_frag.c for both frag & reass.
  */
 #ifndef IP_REASS_DEBUG
 #define IP_REASS_DEBUG                  LWIP_DBG_OFF
 #endif
 
 /**
  * RAW_DEBUG: Enable debugging in raw.c.
  */
 #ifndef RAW_DEBUG
 #define RAW_DEBUG                       LWIP_DBG_OFF
 #endif
 
 /**
  * MEM_DEBUG: Enable debugging in mem.c.
  */
 #ifndef MEM_DEBUG
 #define MEM_DEBUG                       LWIP_DBG_OFF
 #endif
 
 /**
  * MEMP_DEBUG: Enable debugging in memp.c.
  */
 #ifndef MEMP_DEBUG
 #define MEMP_DEBUG                      LWIP_DBG_OFF
 #endif
 
 /**
  * SYS_DEBUG: Enable debugging in sys.c.
  */
 #ifndef SYS_DEBUG
 #define SYS_DEBUG                       LWIP_DBG_OFF
 #endif
 
 /**
  * TCP_DEBUG: Enable debugging for TCP.
  */
 #ifndef TCP_DEBUG
 #define TCP_DEBUG                       LWIP_DBG_OFF
 #endif
 
 /**
  * TCP_INPUT_DEBUG: Enable debugging in tcp_in.c for incoming debug.
  */
 #ifndef TCP_INPUT_DEBUG
 #define TCP_INPUT_DEBUG                 LWIP_DBG_OFF
 #endif
 
 /**
  * TCP_FR_DEBUG: Enable debugging in tcp_in.c for fast retransmit.
  */
 #ifndef TCP_FR_DEBUG
 #define TCP_FR_DEBUG                    LWIP_DBG_OFF
 #endif
 
 /**
  * TCP_RTO_DEBUG: Enable debugging in TCP for retransmit
  * timeout.
  */
 #ifndef TCP_RTO_DEBUG
 #define TCP_RTO_DEBUG                   LWIP_DBG_OFF
 #endif
 
 /**
  * TCP_CWND_DEBUG: Enable debugging for TCP congestion window.
  */
 #ifndef TCP_CWND_DEBUG
 #define TCP_CWND_DEBUG                  LWIP_DBG_OFF
 #endif
 
 /**
  * TCP_WND_DEBUG: Enable debugging in tcp_in.c for window updating.
  */
 #ifndef TCP_WND_DEBUG
 #define TCP_WND_DEBUG                   LWIP_DBG_OFF
 #endif
 
 /**
  * TCP_OUTPUT_DEBUG: Enable debugging in tcp_out.c output functions.
  */
 #ifndef TCP_OUTPUT_DEBUG
 #define TCP_OUTPUT_DEBUG                LWIP_DBG_OFF
 #endif
 
 /**
  * TCP_RST_DEBUG: Enable debugging for TCP with the RST message.
  */
 #ifndef TCP_RST_DEBUG
 #define TCP_RST_DEBUG                   LWIP_DBG_OFF
 #endif
 
 /**
  * TCP_QLEN_DEBUG: Enable debugging for TCP queue lengths.
  */
 #ifndef TCP_QLEN_DEBUG
 #define TCP_QLEN_DEBUG                  LWIP_DBG_OFF
 #endif
 
 /**
  * UDP_DEBUG: Enable debugging in UDP.
  */
 #ifndef UDP_DEBUG
 #define UDP_DEBUG                       LWIP_DBG_OFF
 #endif
 
 /**
  * TCPIP_DEBUG: Enable debugging in tcpip.c.
  */
 #ifndef TCPIP_DEBUG
 #define TCPIP_DEBUG                     LWIP_DBG_OFF
 #endif
 
 /**
  * PPP_DEBUG: Enable debugging for PPP.
  */
 #ifndef PPP_DEBUG
 #define PPP_DEBUG                       LWIP_DBG_OFF
 #endif
 
 /**
  * SLIP_DEBUG: Enable debugging in slipif.c.
  */
 #ifndef SLIP_DEBUG
 #define SLIP_DEBUG                      LWIP_DBG_OFF
 #endif
 
 /**
  * DHCP_DEBUG: Enable debugging in dhcp.c.
  */
 #ifndef DHCP_DEBUG
 #define DHCP_DEBUG                      LWIP_DBG_OFF
 #endif
 
 /**
  * AUTOIP_DEBUG: Enable debugging in autoip.c.
  */
 #ifndef AUTOIP_DEBUG
 #define AUTOIP_DEBUG                    LWIP_DBG_OFF
 #endif
 
 /**
  * SNMP_MSG_DEBUG: Enable debugging for SNMP messages.
  */
 #ifndef SNMP_MSG_DEBUG
 #define SNMP_MSG_DEBUG                  LWIP_DBG_OFF
 #endif
 
 /**
  * SNMP_MIB_DEBUG: Enable debugging for SNMP MIBs.
  */
 #ifndef SNMP_MIB_DEBUG
 #define SNMP_MIB_DEBUG                  LWIP_DBG_OFF
 #endif
 
 /**
  * DNS_DEBUG: Enable debugging for DNS.
  */
 #ifndef DNS_DEBUG
 #define DNS_DEBUG                       LWIP_DBG_OFF
 #endif
 
 #endif /* __LWIP_OPT_H__ */