[LTP] [RFC PATCH v7 02/11] network/stress: Add library test_net_stress.sh

[Petr Vorel]

> On 07/25/2017 12:57 PM, Petr Vorel wrote:
> > Hi Alexey,

> >>> +export OCTET_3_IPV4_UNUSED=${OCTET_3_IPV4_UNUSED:-23} # x.x.N.x
> >>> +export OCTET_4_LHOST_IPV4_HOST_UNUSED=${OCTET_4_LHOST_IPV4_HOST_UNUSED:-2} # x.x.x.N
> >>> +export OCTET_4_RHOST_IPV4_HOST_UNUSED=${OCTET_4_RHOST_IPV4_HOST_UNUSED:-1} # x.x.x.N
> >>> +export LHOST_IPV4_HOST_UNUSED="${OCTET_3_IPV4_UNUSED}.${OCTET_4_LHOST_IPV4_HOST_UNUSED}"
> >>> +export RHOST_IPV4_HOST_UNUSED="${OCTET_3_IPV4_UNUSED}.${OCTET_4_RHOST_IPV4_HOST_UNUSED}"
> >>> +export LHOST_IPV4_UNUSED="${IPV4_NET16_UNUSED}.$LHOST_IPV4_HOST_UNUSED"
> >>> +export RHOST_IPV4_UNUSED="${IPV4_NET16_UNUSED}.$RHOST_IPV4_HOST_UNUSED"
> >>> +
> >>> +export OCTET_3_IPV6_UNUSED="${OCTET_3_IPV6_UNUSED:-:0}"
> >>> +export OCTET_4_LHOST_IPV6_HOST_UNUSED=${OCTET_4_LHOST_IPV6_HOST_UNUSED:-2}
> >>> +export OCTET_4_RHOST_IPV6_HOST_UNUSED=${OCTET_4_RHOST_IPV6_HOST_UNUSED:-1}
> >>> +export LHOST_IPV6_HOST_UNUSED="${OCTET_3_IPV6_UNUSED}:${OCTET_4_LHOST_IPV6_HOST_UNUSED}"
> >>> +export RHOST_IPV6_HOST_UNUSED="${OCTET_3_IPV6_UNUSED}:${OCTET_4_RHOST_IPV6_HOST_UNUSED}"
> >>> +export LHOST_IPV6_UNUSED="${IPV6_NET32_UNUSED}:$LHOST_IPV6_HOST_UNUSED"
> >>> +export RHOST_IPV6_UNUSED="${IPV6_NET32_UNUSED}:$RHOST_IPV6_HOST_UNUSED"
> >> Hmm, what is the purpose of adding these variables to the library?
> >> Why someone would need to redefine any of them?
> > I thought someone might appreciate ability to full control of IP
> > addresses, but you're right it's probably useless.
> > If you don't mind, I'll keep {L,R}HOST_IPV{4,6}_UNUSED variables as they are used in many scripts
> > (DRY approach) and delete the rest of variables.


> What about adding a new function similar to tst_ipaddr()?

> tst_ipaddr_un(), tst_ipaddr_new(), etc.? Probably we would need to add
> some optional counter parameter along with lhost/rhost...

How about this?

tst_ipaddr_un()
{
	local type="${1:-lhost}"
	local counter="${2:-1}"
	local host net max_counter max_net max_host tmp

	[ "$TST_IPV6" ] && max_net=65536 || max_net=256
	max_host=$((max_net - 2))
	max_counter=$((max_host * max_net / 2))

	if [ $counter -gt $max_counter ]; then
		tst_resm TCONF "'$counter' higher than max counter limit '$max_counter'"
	fi

	tmp=$((counter * 2))
	[ "$type" = "rhost" ] && tmp=$((tmp - 1))

	host=$((tmp % max_host))
	net=$((tmp / max_host))
	[ $host -eq 0 ] && { host=$max_host; net=$((net - 1)); }

	if [ "$TST_IPV6" ]; then
		echo "${IPV6_NET32_UNUSED}::$(printf %x:%x ${net} ${host})"
	else
		echo "${IPV4_NET16_UNUSED}.${net}.${host}"
	fi
}

Given the fact that most of the tests needs just one IP address (the
exception are route4-change-{if,gw}, if-{addr,route}-{adddel,addlarge}) it's probably too
overhead and error prone. I mean working with last octet/hextet might be enough.

And if we want to work with more than last octet, we might appreciate to be able to
specify (optionally) third octet as well ($net variable).
Scripts which could benefit from it are at least:
if-{addr,route}-addlarge, route4-change-if.


Kind regards,
Petr