mbuf doubts

[Giovanni P. Tirloni]

* Jerry Toung (jtoung at arc.nasa.gov) wrote:
> Giovani,
> 
> you will find the answer to your question in "tcp/ip illustrated, volume 2: 
> the implementation" in chapter 2.
> 
> But to briefly answer your question, yes, there are 4 different types of 
> mbufs, depending on the m_flags value.
> 1) m_flags = 0 and mbuf contains only data up to 108 bytes.
> 2) m_flags = M_PKTHDR to designate a packet header.
> 3)m_flags = M_EXT. In a situation where a user process write() in a buffer > 
> 256 bytes, the system allocates a cluster to hold that data.
> 4) m_flags = M_EXT|M_PKTHDR
> 
> and yes when  using clusters, the memory in the mbuf is unsed.
> 
> hop that  helped.

 Thank you very much Justin and Jerry for the answers. They were very
 helpful.

 I'm already getting my copy of Steven's :-)

 --
 Giovanni P. Tirloni <gpt at tirloni.org>
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