Re: [PATCH] test: Select first reported IPv6 address for guest/host comparison

[David Gibson <david@gibson.dropbear.id.au>]

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On Fri, Dec 08, 2023 at 06:49:32PM +0100, Stefano Brivio wrote:
> If we run passt nested (a guest connected via passt to a guest
> connected via passt to the host), the first guest (L1) typically has
> two IPv6 addresses: one formed from the prefix assigned via SLAAC,
> and another one assigned via DHCPv6 (to match the address on the
> host).

Hmm... it can't be just that there are multible IPv6 addresses here
that's the problem.  I usually have multiple IPv6 unicast addresses on
my laptop (one for the wifi, one for wired) and I already got that
working.

Possibly it's that there are multiple addresses on the same interface?
But see below..

> When we select addresses for comparison, in this case, we have
> multiple global unicast addresses. Selecting the first reported one
> on both host and guest is not entirely correct (in theory, the order
> might differ), but works reasonably well.

That approach seems good, in principle

> Use the trick from 5beef085978e ("test: Only select a single
> interface or gateway in tests") to ask jq(1) for the first address
> returned by the query.

But that patch was selecting gateways, not local addresses, so I don't
think  the same syntax makes sense.

> 
> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
> ---
>  test/passt/dhcp       | 8 ++++----
>  test/passt/ndp        | 4 ++--
>  test/pasta/dhcp       | 8 ++++----
>  test/pasta/ndp        | 4 ++--
>  test/two_guests/basic | 6 +++---
>  5 files changed, 15 insertions(+), 15 deletions(-)
> 
> diff --git a/test/passt/dhcp b/test/passt/dhcp
> index 7272755..b428064 100644
> --- a/test/passt/dhcp
> +++ b/test/passt/dhcp
> @@ -22,8 +22,8 @@ check	[ -n "__IFNAME__" ]
>  
>  test	DHCP: address
>  guest	/sbin/dhclient -4 __IFNAME__
> -gout	ADDR ip -j -4 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[0].local'
> -hout	HOST_ADDR ip -j -4 addr show|jq -rM '.[] | select(.ifname == "__HOST_IFNAME__").addr_info[0].local'
> +gout	ADDR ip -j -4 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME__").addr_info[0].local] | .[0]'
> +hout	HOST_ADDR ip -j -4 addr show|jq -rM '[.[] | select(.ifname == "__HOST_IFNAME__").addr_info[0].local] | .[0]'

I'm confused by this.  The 'addr_info[0]' should already be selecting
the first address from each interface, so the outer '.[0]' would only
be doing something if multiple interfaces are selected, and I'm not
quite sure why that would happen.

In fact, I suspect this one was right all along... 

>  check	[ "__ADDR__" = "__HOST_ADDR__" ]
>  
>  test	DHCP: route
> @@ -49,8 +49,8 @@ check	[ "__SEARCH__" = "__HOST_SEARCH__" ]
>  
>  test	DHCPv6: address
>  guest	/sbin/dhclient -6 __IFNAME__
> -gout	ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.prefixlen == 128).local'
> -hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__HOST_IFNAME6__").addr_info[] | select(.scope == "global").local'
> +gout	ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.prefixlen == 128).local] | .[0]'
> +hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname ==
>  "__HOST_IFNAME6__").addr_info[] | select(.scope == "global").local]
>  | .[0]'

... but this one isn't, because it is .addr_info[].  Previously the
second 'select' has picked out only one, but not in this situation.
So here the change makes sense to me.

>  check	[ "__ADDR6__" = "__HOST_ADDR6__" ]
>  
>  test	DHCPv6: route
> diff --git a/test/passt/ndp b/test/passt/ndp
> index 6de4081..7b2dbfe 100644
> --- a/test/passt/ndp
> +++ b/test/passt/ndp
> @@ -21,9 +21,9 @@ hout	HOST_IFNAME6 ip -j -6 route show|jq -rM '[.[] | select(.dst == "default").d
>  check	[ -n "__IFNAME__" ]
>  
>  test	SLAAC: prefix
> -gout	ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global" and .prefixlen == 64).local'
> +gout	ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global" and .prefixlen == 64).local] | .[0]'
>  gout	PREFIX6 sipcalc __ADDR6__/64 | grep prefix | cut -d' ' -f4
> -hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__HOST_IFNAME6__").addr_info[] | select(.scope == "global").local'
> +hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__HOST_IFNAME6__").addr_info[] | select(.scope == "global").local] | .[0]'
>  hout	HOST_PREFIX6 sipcalc __HOST_ADDR6__/64 | grep prefix | cut -d' ' -f4
>  check	[ "__PREFIX6__" = "__HOST_PREFIX6__" ]
>  
> diff --git a/test/pasta/dhcp b/test/pasta/dhcp
> index 309001b..b4f6f60 100644
> --- a/test/pasta/dhcp
> +++ b/test/pasta/dhcp
> @@ -20,8 +20,8 @@ check	[ -n "__IFNAME__" ]
>  
>  test	DHCP: address
>  ns	/sbin/dhclient -4 --no-pid __IFNAME__
> -nsout	ADDR ip -j -4 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[0].local'
> -hout	HOST_ADDR ip -j -4 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[0].local'
> +nsout	ADDR ip -j -4 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME__").addr_info[0].local] | .[0]'
> +hout	HOST_ADDR ip -j -4 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME__").addr_info[0].local] | .[0]'
>  check	[ __ADDR__ = __HOST_ADDR__ ]
>  
>  test	DHCP: route
> @@ -36,8 +36,8 @@ check	[ __MTU__ = 65520 ]
>  test	DHCPv6: address
>  ns	/sbin/dhclient -6 --no-pid __IFNAME__
>  hout	HOST_IFNAME6 ip -j -6 route show|jq -rM '[.[] | select(.dst == "default").dev] | .[0]'
> -nsout	ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.prefixlen == 128).local'
> -hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__HOST_IFNAME6__").addr_info[] | select(.scope == "global").local'
> +nsout	ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.prefixlen == 128).local] | .[0]'
> +hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__HOST_IFNAME6__").addr_info[] | select(.scope == "global").local] | .[0]'
>  check	[ __ADDR6__ = __HOST_ADDR6__ ]
>  
>  test	DHCPv6: route
> diff --git a/test/pasta/ndp b/test/pasta/ndp
> index bb33110..2a8afe6 100644
> --- a/test/pasta/ndp
> +++ b/test/pasta/ndp
> @@ -21,9 +21,9 @@ ns	ip link set dev __IFNAME__ up
>  sleep	2
>  
>  test	SLAAC: prefix
> -nsout	ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global" and .prefixlen == 64).local'
> +nsout	ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global" and .prefixlen == 64).local] | .[0]'
>  nsout	PREFIX6 sipcalc __ADDR6__/64 | grep prefix | cut -d' ' -f4
> -hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global").local'
> +hout	HOST_ADDR6 ip -j -6 addr show|jq -rM ['.[] | select(.ifname == "__IFNAME__").addr_info[] | select(.scope == "global").local] | .[0]'
>  hout	HOST_PREFIX6 sipcalc __HOST_ADDR6__/64 | grep prefix | cut -d' ' -f4
>  check	[ "__PREFIX6__" = "__HOST_PREFIX6__" ]
>  
> diff --git a/test/two_guests/basic b/test/two_guests/basic
> index 09fbd3e..fa0608b 100644
> --- a/test/two_guests/basic
> +++ b/test/two_guests/basic
> @@ -39,9 +39,9 @@ test	DHCPv6: addresses
>  sleep	2
>  guest1	/sbin/dhclient -6 __IFNAME1__
>  guest2	/sbin/dhclient -6 __IFNAME2__
> -g1out	ADDR1_6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME1__").addr_info[] | select(.prefixlen == 128).local'
> -g2out	ADDR2_6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__IFNAME2__").addr_info[] | select(.prefixlen == 128).local'
> -hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '.[] | select(.ifname == "__HOST_IFNAME6__").addr_info[] | select(.scope == "global").local'
> +g1out	ADDR1_6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME1__").addr_info[] | select(.prefixlen == 128).local] | .[0]'
> +g2out	ADDR2_6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__IFNAME2__").addr_info[] | select(.prefixlen == 128).local] | .[0]'
> +hout	HOST_ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__HOST_IFNAME6__").addr_info[] | select(.scope == "global").local] | .[0]'
>  check	[ "__ADDR1_6__" = "__HOST_ADDR6__" ]
>  check	[ "__ADDR2_6__" = "__HOST_ADDR6__" ]
>  

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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