Re: [Qemu-devel] [PATCH 2/2] [SLIRP] Delayed IP packets

[Jan Kiszka]

On 2011-07-27 12:14, Fabien Chouteau wrote:
> On 27/07/2011 11:30, Jan Kiszka wrote:
>> On 2011-07-26 18:21, Fabien Chouteau wrote:
>>> In the current implementation, if Slirp tries to send an IP packet to a 
>>> client
>>> with an unknown hardware address, the packet is simply dropped and an ARP
>>> request is sent (if_encap in slirp/slirp.c).
>>>
>>> This patch adds a list of delayed IP packets to handle such cases. If the
>>> hardware address is unknown, Slirp inserts the packet in delayed list and 
>>> sends
>>> an ARP request. Each time the ARP table is updated Slirp retries to send the
>>> packet.
>>
>> Haven't looked at details yet, just two general thoughts so far:
>>
>> We already have queues for outgoing packets, why can't we reuse that
>> infrastructure? That would also avoid additional memory allocations.
>> Delayed packets should be requeued at the end and only one attempt to
>> send them should be performed per queue flush.
> 
> Sure, I didn't know about these queues. Where are they implemented?

Check e.g. what happens in and is documented for if_start().

Jan

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