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

On Mon, Dec 11, 2023 at 10:00:58AM +0100, Stefano Brivio wrote:

On Mon, 11 Dec 2023 13:05:20 +1100 David Gibson wrote:

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On Fri, Dec 08, 2023 at 06:49:32PM +0100, Stefano Brivio wrote:

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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?

Yes, the guest has a single interface and multiple addresses for it, I'll change the commit message.

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But see below..

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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

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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.

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Signed-off-by: Stefano Brivio --- 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...

Right, this doesn't make sense, I just went too far with the copy and paste. Same as for the pasta/dhcp change below. There are actually no issues with IPv4. I'll drop those.

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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.

Here we want to use .addr_info[] because we want to filter further on prefixlen or scope. But once we've done that, if we have two addresses, we have to pick one.

Yes, exactly. -- 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