Re: [lwip-users] Problem with large messages and netconn_write

[Ken Smith]

Hi Andreas,

I'm on the exact same platform you are and have encountered the exact
same problem.  I based my implementation on FreeRTOS-4.2.1 and used
FreeRTOS/Demo/lwIP_Demo_Rowley_ARM7 for the lwIP configuration and
EMAC driver.  First some code for reference.  These lines come from
FreeRTOS-5.1.2's Emac.h from lwIP_Demo_Rowley_ARM7.

 27 /* Number of Transmit buffers */
 28 #define NB_TX_BUFFERS                   ( MEMP_NUM_PBUF / 2 )
 29
 30 /* Size of each Transmit buffer. */
 31 #define ETH_TX_BUFFER_SIZE              ( PBUF_POOL_BUFSIZE  )

My problem was that I had set NB_TX_BUFFERS to 2 in Emac.h.
ETH_TX_BUFFER_SIZE is based on lwIP's value for PBUF_POOL_BUFSIZE in
this port.  My value was the default which is based on TCP_MSS.  My
value for TCP_MSS was 300 so PBUF_POOL_BUFSIZE was 344.  So if I tried
to send a packet whose data+header exceeded 344x2=688, lEMACSend in
SAM7_EMAC.c would timeout after buffering the first 688 bytes and
bail.  It would never flag a transmission start since it couldn't
queue an entire packet and the buffer would be full from that point
forward.  End game.

I solved the problem by increasing TCP_MSS to 1500 in lwipopts.h and
NB_TX_BUFFERS to 4 in Emac.h.

I see from your lwipopts.h file that you have PBUF_POOL_BUFSIZE set to
128 and MEMP_NUM_PBUF set to 16.  If you're using the default Emac.h
that comes with this port (I'm still assuming you are using the same
FreeRTOS demo that I did so please forgive my presumption), that gives
you 128 * (16 / 2) = 1024 bytes.  Your 950 byte packet + headers (74
bytes of headers seems unlikely but who knows (someone on this list
probably!)) may just be a little too big to fit into your EMAC
transmission queue sending you off into the same la-la land I ended up
in.

Maybe this isn't your problem.  If it is, you're in luck because the
fix is easy: give your EMAC driver more RAM.

    Kind regards,
    Ken

2009/3/20  <address@hidden>:
> A package capture is attaced.
>
> lwipopts.h
>
> /* ---------- TCP/IP thread and mailbox settings ---------- */
> #define  TCPIP_THREAD_NAME                "tcpip_thread"
> #define  TCPIP_THREAD_STACKSIZE           500
> #define  TCPIP_THREAD_PRIO                1
>
> /* Number of elements for each mailbox queue */
> #define  TCPIP_MBOX_SIZE                  6
> #define  DEFAULT_RAW_RECVMBOX_SIZE        6
> #define  DEFAULT_UDP_RECVMBOX_SIZE        6
> #define  DEFAULT_TCP_RECVMBOX_SIZE        6
> #define  DEFAULT_ACCEPTMBOX_SIZE          6
>
>
> /* ---------- System settings ---------- */
> #define NO_SYS                     0
> #define LWIP_SOCKET               (NO_SYS==0)
> #define LWIP_NETCONN              (NO_SYS==0)
>
>
> /* ---------- Debug settings ---------- */
> #ifdef LWIP_DEBUG
>
> #define LWIP_DBG_MIN_LEVEL         0
> #define PPP_DEBUG                  LWIP_DBG_OFF
> #define MEM_DEBUG                  LWIP_DBG_OFF
> #define MEMP_DEBUG                 LWIP_DBG_OFF
> #define PBUF_DEBUG                 LWIP_DBG_OFF
> #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 DNS_DEBUG                  LWIP_DBG_ON
> #define AUTOIP_DEBUG               LWIP_DBG_OFF
> #define DHCP_DEBUG                 LWIP_DBG_ON
> #define IP_DEBUG                   LWIP_DBG_ON
> #define IP_REASS_DEBUG             LWIP_DBG_OFF
> #define ICMP_DEBUG                 LWIP_DBG_OFF
> #define IGMP_DEBUG                 LWIP_DBG_OFF
> #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_OFF
> #define TCP_CWND_DEBUG             LWIP_DBG_OFF
> #define TCP_WND_DEBUG              LWIP_DBG_OFF
> #define TCP_FR_DEBUG               LWIP_DBG_OFF
> #define TCP_QLEN_DEBUG             LWIP_DBG_OFF
> #define TCP_RST_DEBUG              LWIP_DBG_OFF
>
> #define LWIP_DBG_TYPES_ON
> (LWIP_DBG_ON|LWIP_DBG_TRACE|LWIP_DBG_STATE|LWIP_DBG_FRESH|LWIP_DBG_HALT)
>
> #else
>
> #define LWIP_DBG_TYPES_ON         (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. */
> #define MEM_ALIGNMENT           4
>
> /* 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. */
> #define MEM_SIZE                2000
>
> /* 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. */
> #define MEMP_NUM_PBUF           16 //20
> /* MEMP_NUM_RAW_PCB: the number of UDP protocol control blocks. One
>   per active RAW "connection". */
> #define MEMP_NUM_RAW_PCB        3
> /* MEMP_NUM_UDP_PCB: the number of UDP protocol control blocks. One
>   per active UDP "connection". */
> #define MEMP_NUM_UDP_PCB        3 //4
> /* MEMP_NUM_TCP_PCB: the number of simulatenously active TCP
>   connections. */
> #define MEMP_NUM_TCP_PCB        6 //10
> /* MEMP_NUM_TCP_PCB_LISTEN: the number of listening TCP
>   connections. */
> #define MEMP_NUM_TCP_PCB_LISTEN 5 //8
> /* MEMP_NUM_TCP_SEG: the number of simultaneously queued TCP
>   segments. */
> #define MEMP_NUM_TCP_SEG        5 //8
> /* MEMP_NUM_SYS_TIMEOUT: the number of simulateously active
>   timeouts. */
> #define MEMP_NUM_SYS_TIMEOUT    10
>
>
> /* 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. */
> #define MEMP_NUM_NETBUF         4
> /* MEMP_NUM_NETCONN: the number of struct netconns. */
> #define MEMP_NUM_NETCONN        4
> /* MEMP_NUM_TCPIP_MSG_*: the number of struct tcpip_msg, which is used
>   for sequential API communication and incoming packets. Used in
>   src/api/tcpip.c. */
> #define MEMP_NUM_TCPIP_MSG_API   16
> #define MEMP_NUM_TCPIP_MSG_INPKT 16
>
>
> /* ---------- Pbuf options ---------- */
> /* PBUF_POOL_SIZE: the number of buffers in the pbuf pool. */
> #define PBUF_POOL_SIZE          32 //2 //4
>
> /* PBUF_POOL_BUFSIZE: the size of each pbuf in the pbuf pool. */
> #define PBUF_POOL_BUFSIZE       128 //1500
>
> /* PBUF_LINK_HLEN: the number of bytes that should be allocated for a
>   link level header. */
> #define PBUF_LINK_HLEN          16
>
> /** SYS_LIGHTWEIGHT_PROT
>  * define 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.
> */
> #define SYS_LIGHTWEIGHT_PROT    (NO_SYS==0)
>
>
> /* ---------- 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         1
>
> /* TCP Maximum segment size. */
> #define TCP_MSS                 1024 //1500
>
> /* TCP sender buffer space (bytes). */
> #define TCP_SND_BUF             2048 //1500
>
> /* TCP sender buffer space (pbufs). This must be at least = 2 *
>   TCP_SND_BUF/TCP_MSS for things to work. */
> #define TCP_SND_QUEUELEN        (4 * TCP_SND_BUF/TCP_MSS)
>
> /* TCP receive window. */
> #define TCP_WND                 8096 //1500
>
> /* Maximum number of retransmissions of data segments. */
> #define TCP_MAXRTX              12
>
> /* Maximum number of retransmissions of SYN segments. */
> #define TCP_SYNMAXRTX           4
>
>
> /* ---------- ARP options ---------- */
> #define LWIP_ARP                1
> #define ARP_TABLE_SIZE          10
> #define ARP_QUEUEING            1
>
>
> /* ---------- 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. */
> #define IP_FORWARD              0 //1
>
> /* IP reassembly and segmentation.These are orthogonal even
> * if they both deal with IP fragments */
> #define IP_REASSEMBLY           1
> #define IP_REASS_MAX_PBUFS      10
> #define MEMP_NUM_REASSDATA      10
> #define IP_FRAG                 1
>
> /* If defined to 1, IP options are allowed (but not parsed). If
>   defined to 0, all packets with IP options are dropped. */
> //#define IP_OPTIONS              1
>
>
> /* ---------- ICMP options ---------- */
> #define ICMP_TTL                255
>
>
> /* ---------- DHCP options ---------- */
> /* Define LWIP_DHCP to 1 if you want DHCP configuration of
>   interfaces. */
> #define LWIP_DHCP               1 //0
>
> /* 1 if you want to do an ARP check on the offered address
>   (recommended). */
> #define DHCP_DOES_ARP_CHECK     (LWIP_DHCP)
>
>
> /* ---------- AUTOIP options ------- */
> #define LWIP_AUTOIP             0
> #define LWIP_DHCP_AUTOIP_COOP  (LWIP_DHCP && LWIP_AUTOIP)
>
>
> /* ---------- UDP options ---------- */
> #define LWIP_UDP                1
> #define LWIP_UDPLITE            1
> #define UDP_TTL                 255
>
>
> /* ---------- RAW options ---------- */
> #define  LWIP_RAW                         0
>
>
> /* ---------- DMS options ---------- */
> #define  LWIP_DNS                         1
>
>
> /* ---------- Statistics options ---------- */
> #define LWIP_STATS              1
> #define LWIP_STATS_DISPLAY      1
>
> #if LWIP_STATS
> #define LINK_STATS 1
> #define IP_STATS   1
> #define ICMP_STATS 1
> #define UDP_STATS  1
> #define TCP_STATS  1
> #define MEM_STATS  1
> #define MEMP_STATS 1
> #define PBUF_STATS 1
> #define SYS_STATS  1
> #endif /* LWIP_STATS */
>
>
> //#define LWIP_PROVIDE_ERRNO 1
>
>
> /* ---------- PPP options ---------- */
> #define PPP_SUPPORT             0      /* Set > 0 for PPP */
>
> #if PPP_SUPPORT
>
> #define NUM_PPP                 1      /* Max PPP sessions. */
>
> /* Select modules to enable. Ideally these would be set in the makefile
> but
> * we're limited by the command line length so you need to modify the
> settings
> * in this file.
> */
> #define PPPOE_SUPPORT           1
> #define PPPOS_SUPPORT           1
> #define PAP_SUPPORT             1      /* Set > 0 for PAP. */
> #define CHAP_SUPPORT            1      /* Set > 0 for CHAP. */
> #define MSCHAP_SUPPORT          0      /* Set > 0 for MSCHAP (NOT
> FUNCTIONAL!) */
> #define CBCP_SUPPORT            0      /* Set > 0 for CBCP (NOT
> FUNCTIONAL!) */
> #define CCP_SUPPORT             0      /* Set > 0 for CCP (NOT
> FUNCTIONAL!) */
> #define VJ_SUPPORT              1      /* Set > 0 for VJ header
> compression. */
> #define MD5_SUPPORT             1      /* Set > 0 for MD5 (see also
> CHAP) */
>
> #endif /* PPP_SUPPORT */
>
>
>
>
> #endif /* __LWIPOPTS_H__ */
>
> On Fri, 20 Mar 2009 10:06 +0000, "Kieran Mansley" <address@hidden>
> wrote:
>> On Fri, 2009-03-20 at 11:00 +0100, address@hidden wrote:
>>
>> > The problem appears when the entire Ethernet frame going out exceeds 950
>> > bytes (TCP package exceeds 896 bytes). The package is never received by
>> > the computer (direct connection, using a package sniffing program to
>> > check the traffic). netconn_write returns ERR_OK but the lwip stack
>> > isn’t working any more (doesn’t reply to an ARP request from the
>> > computer).
>>
>> Can you show us your lwipopts.h, and if possible a packet capture of it
>> going wrong?
>>
>> Thanks
>>
>> Kieran
>>
>>
>>
>> _______________________________________________
>> lwip-users mailing list
>> address@hidden
>> http://lists.nongnu.org/mailman/listinfo/lwip-users
>
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