Re: [lwip-users] lwip-users Digest, Vol 234, Issue 6

[Peter]

>Subject: [lwip-users] LwIP Project Question


Here is a sample lwipopts.h which I have spent made days or weeks on.
It contains a lot of potentially useful comments.

A lot of it won't apply to your project.

The values override defaults in opt.h.

I am running under FreeRTOS.

LWIP has been largely abandoned now. It is very good but it is now
over 15 years old and most of the people working on it have moved on,
so getting support is hard. You can try e.g. here
https://www.eevblog.com/forum/microcontrollers/anyone-here-familiar-with-lwip/

/**

******************************************************************************
  * @file    LwIP/LwIP_HTTP_Server_Netconn_RTOS/Inc/lwipopts.h
  * @author  MCD Application Team
  * @brief   lwIP Options Configuration.

******************************************************************************
*
*       This sort of explains the memory usage
* https://lwip-users.nongnu.narkive.com/dkzkPa8l/lwip-memory-settings
*       https://www.cnblogs.com/shangdawei/p/3494148.html
*       https://lwip.fandom.com/wiki/Tuning_TCP
* https://groups.google.com/g/osdeve_mirror_tcpip_lwip/c/lFYJ7Fw0Cxg
*       ST UM1713 document gives an overview of integrating all this.
*
*
*
*
*
*
*
*
  */
#ifndef __LWIPOPTS_H__
#define __LWIPOPTS_H__

/**
 * NO_SYS==1: Provides VERY minimal functionality. Otherwise,
 * use lwIP facilities.
 */
#define NO_SYS                          0

// Flag to make LWIP API thread-safe. The netconn and socket APIs are
claimed
// to be thread-safe anyway. The raw API is never thread-safe.
// A huge amount of online discussion on this topic; most of it
unclear, but
// ON (1) seems to be recommended, as being more efficient.

#define LWIP_TCPIP_CORE_LOCKING         1

// If LWIP_TCPIP_CORE_LOCKING=0 then these two need to be 1
// See https://www.nongnu.org/lwip/2_1_x/multithreading.html
//#define LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT 1
//#define SYS_LIGHTWEIGHT_PROT            1

// This places more objects into the static block defined by MEM_SIZE.
// Uses mem_malloc/mem_free instead of the lwip pool allocator.
// MEM_SIZE now needs to be increased by about 10k.
// It doesn't magically produce extra memory, and causes crashes.
// There is also a performance loss, apparently. AVOID.
#define MEMP_MEM_MALLOC                         0


//NC: Need for sending PING messages by keepalive
#define LWIP_RAW                                        1
#define DEFAULT_RAW_RECVMBOX_SIZE       4

// For ETHSER
#define LWIP_TCP_KEEPALIVE                      1

/*-----------------------------------------------------------------------------*/

/* LwIP Stack Parameters (modified compared to initialization value in
opt.h) -*/
/* Parameters set in STM32CubeMX LwIP Configuration GUI -*/

/*----- Value in opt.h for LWIP_DNS: 0 -----*/
#define LWIP_DNS 1

/* ---------- 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. */
#define MEM_ALIGNMENT           4

/*
* MEM_SIZE: the size of the heap memory. This is a statically
allocated block. You can find it
* in the .map file as the symbol ram_heap and you can see how much of
this RAM gets used.
* If MEMP_MEM_MALLOC=0, this holds just the PBUF_ stuff.
* If MEMP_MEM_MALLOC=1 (which is not reliable) this greatly expands
and needs 16k+.
* Empirically this needs to be big enough for at least 4 x
PBUF_POOL_BUFSIZE.
* This value also limits the biggest block size sent out by
netconn_write. With a MEM_SIZE
* of 6k, the biggest block netconn_write (and probably socket write)
will send out is 4k.
* This setting is mostly related to outgoing data.
*/

#define MEM_SIZE                (6*1024)

// MEMP_ structures. Their sizes have been determined experimentally,
by
// increasing them and seeing free RAM changing.

/* 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. */
//NC: Increased to 20 for ethser
#define MEMP_NUM_PBUF           20      // each 1 is 20 bytes of
static RAM

/* MEMP_NUM_UDP_PCB: the number of UDP protocol control blocks. One
   per active UDP "connection". */
#define MEMP_NUM_UDP_PCB        6       // each 1 is 32 bytes of
static RAM

/* MEMP_NUM_TCP_PCB: the number of simultaneously active TCP
   connections. */
//NC: Increased to 20 for ethser
#define MEMP_NUM_TCP_PCB        20      // each 1 is 145 bytes of
static RAM

//NC: Have more sockets available. Is set to 4 in opt.h
#define MEMP_NUM_NETCONN                10

/* MEMP_NUM_TCP_PCB_LISTEN: the number of listening TCP
   connections. */
//NC: Increased to 20 for ethser
#define MEMP_NUM_TCP_PCB_LISTEN 20      // each 1 is 28 bytes of
static RAM

/* MEMP_NUM_TCP_SEG: the number of simultaneously queued TCP
   segments. */
// Was 8; increased to 16 as it improves ETHSER reliability when
running
// HTTP server
#define MEMP_NUM_TCP_SEG        16 // each 1 is 20 bytes of static RAM

/* MEMP_NUM_SYS_TIMEOUT: the number of simulateously active
   timeouts. */
#define MEMP_NUM_SYS_TIMEOUT    10      // each 1 is 16 bytes of
static RAM


/* ---------- Pbuf dynamically allocated buffer blocks  ----------
*
* These settings make little difference to performance, which is
dominated by
* the low_level_input poll period. These PBUFs relate directly to the
netconn API netbufs.
*
* PBUF_POOL_SIZE: the number of buffers in the pbuf pool.
* Statically allocated, so each increment frees up 1.5k of RAM. Any
value under 4 slows
* down the data rate a lot.
* 12/2/23 PH 4 -> 6 fixes TLS blocking of various RTOS tasks (5 almost
does).
* The most this can go to with TLS still having enough free RAM for
its 48k block is ~9.
*/

#define PBUF_POOL_SIZE           6

/* PBUF_POOL_BUFSIZE: the size of each pbuf in the pbuf pool.
** It is better to use MTU sized bufs than 8 x 512 because in say
EditGetData() you are **
** much more likely to get the whole file header in the first packet.
With 512          **
** byte packets the CRLFCRLF marker is only ~64 bytes before the end
of the pkt         **
** Same issue in UploadGetData where we need to get the whole header
in.                **
** However the above issue has been largely solved with the 200ms wait
in the http svr  **
* The +2 is to get a multiple of 4 bytes so the PBUFs are 4-aligned
(for memcpy_fast())
* Probably the +2 is not needed because the PBUFs are 4-aligned anyway
in the LWIP code.
*/

#define PBUF_POOL_BUFSIZE  1500 + PBUF_LINK_ENCAPSULATION_HLEN +
PBUF_LINK_HLEN + 2


/* ---------- TCP options ---------- */
#define LWIP_TCP                1
#define TCP_TTL                 255

/* Controls if TCP should queue segments that arrive out of
   order. Define to 0 if your device is low on memory. */
#define TCP_QUEUE_OOSEQ         0

/* TCP Maximum segment size. */
#define TCP_MSS                 (1500 - 40)       /* TCP_MSS =
(Ethernet MTU - IP header size - TCP header size) */

/* TCP sender buffer space (bytes). */
// Reduced from 4*MSS to leave more room for TX packets in the LWIP
heap (MEM_SIZE).
#define TCP_SND_BUF             (2*TCP_MSS)             // no effect
on static RAM

/*  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. */
// Was 2*; increased to 4* as it improves ETHSER reliability when
running
// HTTP server
#define TCP_SND_QUEUELEN        (4* TCP_SND_BUF/TCP_MSS) // (2*
TCP_SND_BUF/TCP_MSS)

/* TCP advertised receive window. */
// Should be less than PBUF_POOL_SIZE * (PBUF_POOL_BUFSIZE - protocol
headers)
#define TCP_WND                 (2*TCP_MSS)             // no effect
on static RAM


/* ---------- ICMP options ---------- */
#define LWIP_ICMP               1


/* ---------- DHCP options ---------- */
#define LWIP_DHCP               1


/* ---------- UDP options ---------- */
#define LWIP_UDP                1
#define UDP_TTL                 255

// These are build flags which disable the support for the
SOF_BROADCAST option on raw and UDP PCBs
// Commented-out because changing these requires a recompilation, and
an application which receives
// broadcast packets may one day be necessary (set g_eth_multi=true to
disable the packet filter in
// ethernetif.c)
//#define IP_SOF_BROADCAST                1
//#define IP_SOF_BROADCAST_RECV           1


/* ---------- Statistics options ---------- */
#define LWIP_STATS 0

/* ---------- link callback options ---------- */
/* LWIP_NETIF_LINK_CALLBACK==1: Support a callback function from an
interface
 * whenever the link changes (i.e., link down)
 * 8/2022 this is done from the low_level_input RTOS task.
 */
#define LWIP_NETIF_LINK_CALLBACK        0




/*
   --------------------------------------
   ---------- Checksum options ----------
   --------------------------------------
*/

/* 
The STM32F4xx allows computing and verifying the IP, UDP, TCP and ICMP
checksums by hardware:
 - To use this feature let the following define uncommented.
 - To disable it and process by CPU comment the  the checksum.
*/
#define CHECKSUM_BY_HARDWARE 


#ifdef CHECKSUM_BY_HARDWARE
  /* CHECKSUM_GEN_IP==0: Generate checksums by hardware for outgoing
IP packets.*/
  #define CHECKSUM_GEN_IP                 0
  /* CHECKSUM_GEN_UDP==0: Generate checksums by hardware for outgoing
UDP packets.*/
  #define CHECKSUM_GEN_UDP                0
  /* CHECKSUM_GEN_TCP==0: Generate checksums by hardware for outgoing
TCP packets.*/
  #define CHECKSUM_GEN_TCP                0 
  /* CHECKSUM_CHECK_IP==0: Check checksums by hardware for incoming IP
packets.*/
  #define CHECKSUM_CHECK_IP               0
  /* CHECKSUM_CHECK_UDP==0: Check checksums by hardware for incoming
UDP packets.*/
  #define CHECKSUM_CHECK_UDP              0
  /* CHECKSUM_CHECK_TCP==0: Check checksums by hardware for incoming
TCP packets.*/
  #define CHECKSUM_CHECK_TCP              0
  /* CHECKSUM_CHECK_ICMP==0: Check checksums by hardware for incoming
ICMP packets.*/  
  #define CHECKSUM_GEN_ICMP               0
#else
  /* CHECKSUM_GEN_IP==1: Generate checksums in software for outgoing
IP packets.*/
  #define CHECKSUM_GEN_IP                 1
  /* CHECKSUM_GEN_UDP==1: Generate checksums in software for outgoing
UDP packets.*/
  #define CHECKSUM_GEN_UDP                1
  /* CHECKSUM_GEN_TCP==1: Generate checksums in software for outgoing
TCP packets.*/
  #define CHECKSUM_GEN_TCP                1
  /* CHECKSUM_CHECK_IP==1: Check checksums in software for incoming IP
packets.*/
  #define CHECKSUM_CHECK_IP               1
  /* CHECKSUM_CHECK_UDP==1: Check checksums in software for incoming
UDP packets.*/
  #define CHECKSUM_CHECK_UDP              1
  /* CHECKSUM_CHECK_TCP==1: Check checksums in software for incoming
TCP packets.*/
  #define CHECKSUM_CHECK_TCP              1
  /* CHECKSUM_CHECK_ICMP==1: Check checksums by hardware for incoming
ICMP packets.*/  
  #define CHECKSUM_GEN_ICMP               1
#endif


/*
   ----------------------------------------------
   ---------- Sequential layer options ----------
   ----------------------------------------------
*/
/**
 * LWIP_NETCONN==1: Enable Netconn API (require to use api_lib.c)
 */
#define LWIP_NETCONN                    1

/*
   ------------------------------------
   ---------- Socket options ----------
   ------------------------------------
*/
/**
 * LWIP_SOCKET==1: Enable Socket API (require to use sockets.c)
 */
#define LWIP_SOCKET                     1

/*
   ------------------------------------
   ---------- httpd options ----------
   ------------------------------------
*/
/** Set this to 1 to include "fsdata_custom.c" instead of "fsdata.c"
for the
 * file system (to prevent changing the file included in CVS) */
#define HTTPD_USE_CUSTOM_FSDATA   0

/*
   ---------------------------------
   ---------- OS options ----------
   ---------------------------------
*/

#define TCPIP_THREAD_NAME              "TCP/IP"
#define TCPIP_THREAD_STACKSIZE          4096
#define TCPIP_MBOX_SIZE                 6
#define DEFAULT_UDP_RECVMBOX_SIZE       6
#define DEFAULT_TCP_RECVMBOX_SIZE       6
#define DEFAULT_ACCEPTMBOX_SIZE         6
#define DEFAULT_THREAD_STACKSIZE        512
#define TCPIP_THREAD_PRIO               osPriorityHigh  // should be
>= that of any TCP/IP apps

#define LWIP_DEBUG 1

/*
#define IP_DEBUG LWIP_DBG_ON
#define DHCP_DEBUG LWIP_DBG_OFF
#define UDP_DEBUG LWIP_DBG_ON
#define SOCKET_DEBUG_LWIP_DBG_ON
//#define ICMP_DEBUG LWIP_DBG_ON|LWIP_DBG_TRACE
//#define NETIF_DEBUG LWIP_DBG_OFF
#define LWIP_DBG_TYPES_ON  (LWIP_DBG_TRACE|LWIP_DBG_STATE)
*/

#define LWIP_SO_RCVTIMEO        1
#define LWIP_NETIF_HOSTNAME     1
#define SO_REUSE 1

// Defining these produces various errors
//#define LWIP_IPV6                                             1
//#define LWIP_IPV6_DHCP6                               1

/*
// TODO
#ifdef LWIP_DEBUG

#define MEMP_OVERFLOW_CHECK            ( 1 )
#define MEMP_SANITY_CHECK              ( 1 )

#define MEM_DEBUG        LWIP_DBG_OFF
#define MEMP_DEBUG       LWIP_DBG_OFF
#define PBUF_DEBUG       LWIP_DBG_ON
#define API_LIB_DEBUG    LWIP_DBG_ON
#define API_MSG_DEBUG    LWIP_DBG_ON
#define TCPIP_DEBUG      LWIP_DBG_ON
#define NETIF_DEBUG      LWIP_DBG_ON
#define SOCKETS_DEBUG    LWIP_DBG_ON
#define DEMO_DEBUG       LWIP_DBG_ON
#define IP_DEBUG         LWIP_DBG_ON
#define IP6_DEBUG        LWIP_DBG_ON
#define IP_REASS_DEBUG   LWIP_DBG_ON
#define RAW_DEBUG        LWIP_DBG_ON
#define ICMP_DEBUG       LWIP_DBG_ON
#define UDP_DEBUG        LWIP_DBG_ON
#define TCP_DEBUG        LWIP_DBG_ON
#define TCP_INPUT_DEBUG  LWIP_DBG_ON
#define TCP_OUTPUT_DEBUG LWIP_DBG_ON
#define TCP_RTO_DEBUG    LWIP_DBG_ON
#define TCP_CWND_DEBUG   LWIP_DBG_ON
#define TCP_WND_DEBUG    LWIP_DBG_ON
#define TCP_FR_DEBUG     LWIP_DBG_ON
#define TCP_QLEN_DEBUG   LWIP_DBG_ON
#define TCP_RST_DEBUG    LWIP_DBG_ON
#define PPP_DEBUG        LWIP_DBG_OFF

#define LWIP_DBG_TYPES_ON
(LWIP_DBG_ON|LWIP_DBG_TRACE|LWIP_DBG_STATE|LWIP_DBG_FRESH|LWIP_DBG_HALT)

#endif
*/

#endif /* __LWIPOPTS_H__ */