Re: raw socket, IP_HDRINCL byteorder

>	raw socket with IP_HDRINCL uses different network byteorder for some
>	of the IP header fields (ip_off and ip_len).  i think the behavior
>	is confusing, and the culprit is 4.[34]BSD. (4.[34]BSD should have
>	cleaned it up before supplying this API to users)

	i forgot to mention one thing - IP_HDRINCL is used for two reasons:
	- prototyping L4 code (like new transport layer protocol)
	  in this case, we will want byteorder/content to be the same as the
	  ones used in IPv4 kernel code.
	- allow applications to send/receive the whole IPv4 packet as is
	  in this case, we will want fields handled equally as wire format,
	  i.e. network byteorder and ip_len is for the whole packet.

	the 4.[34]BSD kernel code/behavior is biased to the former bullet, i
	guess.  the reality is that we see much more apps use the API for
	the latter bullet than the former.

itojun

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