Re: [lwip-users] memory leak when sending snmp trap

[address@hidden]

Unfortunately, I also don't have that much experience with the snmp 
code, and I did not use traps so far (only snmpwalk). But what I can say 
about your code is that it is likely to fail because you are using the 
snmp functions from an application thread.

At least snmp_send_trap will call the UDP raw API eventually (udp_sendto 
or something like that), which *must not* be called from any other 
thread than lwIP's tcpip_thread or you will run into problems. You 
should correct that and then report if you are still having memory leaks.

Simon

Alexandre Malo wrote:
> Hello,
>  
>    I am having memory leak with a task sending trap.
>  
> Here is my simple task:
>  
> #define MY_SNMP_ENTERPRISE_ID 4464
> #define MY_SNMP_SYSOBJID_LEN 7
> #define MY_SNMP_SYSOBJID {1, 3, 6, 1, 4, 1, MY_SNMP_ENTERPRISE_ID}
>  
> void vSendTrapTask( void * pvParameters )
> {
>    portTickType xLastWakeTime;
>    struct snmp_obj_id objid = {MY_SNMP_SYSOBJID_LEN, MY_SNMP_SYSOBJID};
>    struct snmp_varbind *vb;
>    static unsigned char msg[] = "address@hidden 
> <mailto:address@hidden>";
>    static unsigned char msglen= 22;
>  
>    (void) pvParameters;
>   
>    for ( ;; )
>    {
>       xLastWakeTime = xTaskGetTickCount();
>      
>       vb = snmp_varbind_alloc(&objid,
>                            SNMP_ASN1_OPAQUE,
>                            msglen);
>                              
>       vb->value = &msg;
>            
>       trap_msg.outvb.head = vb;
>       trap_msg.outvb.tail = vb;
>       trap_msg.outvb.count = 1;
>      
>       snmp_send_trap(SNMP_GENTRAP_ENTERPRISESPC, &objid, 0);
>      
>       trap_msg.outvb.head = NULL;
>       trap_msg.outvb.tail = NULL;
>       trap_msg.outvb.count = 0;
>       vb->value = NULL;
>      
>       snmp_varbind_free(vb);
>      
>       // Wait for the next cycle.
>       vTaskDelayUntil( &xLastWakeTime, 10 );
>    }
> }
>  
> Do I use correctly snmp_varbind_alloc?
>  
> I want to notify that the thread works for a random number of sent 
> trap. I tried it more than once and its never the same amount of trap 
> that is received.
>  
> Thanks!
> Alexandre Malo
> ------------------------------------------------------------------------
>
> _______________________________________________
> lwip-users mailing list
> address@hidden
> http://lists.nongnu.org/mailman/listinfo/lwip-users