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STM32F407 + UDP+LWIP big packet problem

lorant124
Associate III
Posted on August 16, 2017 at 00:58

Dear Forum,

I bring forth a frustration question yet I'm uncertain how to approach it.

I have STM32F402, and I can communication over UDP . In cube I reviewed every options but my problem do not solved. 

If I can 

sending data over UDP

 smaller than 1514 byte is every OK - I have Java applicaton to

receive and 

monitoring data from UDP and works good ,  but if I can send over 1514 byte in wireshark seeing every fragmented data and full packet good . But in PC doesnt see any packet. Maybe problem is in header or fragmentation .. I dont know.

Please help me.

My code : 

void udpinit(void){

udp_p = udp_new();

udp_bind(udp_p,IP_ADDR_ANY,port);

udp_connect(udp_p, IP_ADDR_BROADCAST, port);

}

void packet_send(void){

struct pbuf *TxBuffer_p;

TxBuffer_p = pbuf_alloc(PBUF_TRANSPORT, sizeof(adc_data), PBUF_RAM);

memcpy(TxBuffer_p->payload,adc_data,sizeof(adc_data));

udp_send(udp_p,TxBuffer_p);

pbuf_free(TxBuffer_p);

}

#fragmentation #stm32 #cubemx #mtu #udp #lwip
1 REPLY 1
Posted on August 16, 2017 at 10:45

ST appears to be innocent here given you see the fragmented packets in wireshark.

lwip-specific questions are perhaps better to be asked here

https://lists.nongnu.org/mailman/listinfo/lwip-users

 

JW