retrive data from mbuf chain

[Biks N]

Hi,

I am new to FreeBSD kernel programming.

Currently I am trying to work on mbuf data manupulation.

>From my understanding: data (payload) is stored into one or more mufs
which are chained together through m_next pointer.

Now, I need to retrive all data in mbuf chain ( mbufs linked by
m_next). I am working ip_output() in netinet/ip_output.c

Does there exist inbuilt function/macro to retrive all the data in mbuf chain?

thanks in advance :)