Specific question about packet dropping

Specific question about packet dropping

[Javier Domingo]

Hi,

Where are packets dropped?

I reading code I think just found:
- In the NIC
- In the netif_receive_skb

Is there any other place I can have missed?

Javier Domingo

Re: Specific question about packet dropping

[Shan Wei]

Javier Domingo said, at 2012/11/28 18:40:
> Hi,
> 
> Where are packets dropped?
> 
> I reading code I think just found:
> - In the NIC
> - In the netif_receive_skb
> 
> Is there any other place I can have missed?

There is many reasons, following is not whole.

For receiver:
1. NIC
2. __netif_receive_skb(unknown packet type)
3. ip_rcv(abnormal packet, route reason...)
4. tcp/udp (unknown port, receive buff limit..)

For Sender:
1. tcp/udp(send buffer limit)
2. ip(route reason....)
3. arp(resolved_discards)
4. qdisc(queue limit)


Best Regards
Shan Wei

> 
> Javier Domingo
> --
> To unsubscribe from this list: send the line "unsubscribe netdev" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

Re: Specific question about packet dropping

[Shan Wei]

Javier Domingo said, at 2012/11/28 19:50:
> Thank you very much, I (don't know why) thought the packets were being
> smashed in the dma memory.

Maybe your kernel/application handles the packets so slower than that
NIC receives. 

>> Best Regards
>> Shan Wei
>>
>>>
>>> Javier Domingo
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe netdev" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>
>>
>>
> 

Re: Specific question about packet dropping

[Javier Domingo]

I have been reviewing and I think I must have confused terms.

Then, inside the kernel, there are no packet drops for legitime ones.
And I suppose that if an app doesn't read from its socket queue, the
kernel will drop them in the socket queue?
Javier Domingo


2012/11/28 Shan Wei <shanwei88@gmail.com>:
> Javier Domingo said, at 2012/11/28 19:50:
>> Thank you very much, I (don't know why) thought the packets were being
>> smashed in the dma memory.
>
> Maybe your kernel/application handles the packets so slower than that
> NIC receives.
>
>>> Best Regards
>>> Shan Wei
>>>
>>>>
>>>> Javier Domingo
>>>> --
>>>> To unsubscribe from this list: send the line "unsubscribe netdev" in
>>>> the body of a message to majordomo@vger.kernel.org
>>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>>
>>>
>>>
>>
>