test: Wait for DAD on DHCPv6 addresses

After running dhclient -6 we expect the DHCPv6 assigned address to be
immediately usable.  That's true with the Fedora dhclient-script (and the
upstream ISC DHCP one), however it's not true with the Debian
dhclient-script.  The Debian script can complete with the address still
in "tentative" state, and the address won't be usable until Duplicate
Address Detection (DAD) completes.  That's arguably a bug in Debian (see
link below), but for the time being we need to work around it anyway.

We usually get away with this, because by the time we do anything where the
address matters, DAD has completed.  However, it's not robust, so we should
explicitly wait for DAD to complete when we get an DHCPv6 address.

Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1085231

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
David Gibson 2024-10-18 12:35:52 +11:00 committed by Stefano Brivio
parent 75b9c0feb0
commit 53176ca91d
5 changed files with 11 additions and 0 deletions

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@ -49,6 +49,8 @@ check [ "__SEARCH__" = "__HOST_SEARCH__" ]
test DHCPv6: address
guest /sbin/dhclient -6 __IFNAME__
# Wait for DAD to complete
guest while ip -j -6 addr show tentative | jq -e '.[].addr_info'; do sleep 0.1; done
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" and .deprecated != true).local] | .[0]'
check [ "__ADDR6__" = "__HOST_ADDR6__" ]

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@ -52,6 +52,8 @@ check [ "__SEARCH__" = "__HOST_SEARCH__" ]
test DHCPv6: address
guest /sbin/dhclient -6 __IFNAME__
# Wait for DAD to complete
guest while ip -j -6 addr show tentative | jq -e '.[].addr_info'; do sleep 0.1; done
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" and .deprecated != true).local] | .[0]'
check [ "__ADDR6__" = "__HOST_ADDR6__" ]

View file

@ -35,6 +35,8 @@ check [ __MTU__ = 65520 ]
test DHCPv6: address
ns /sbin/dhclient -6 --no-pid __IFNAME__
# Wait for DAD to complete
ns while ip -j -6 addr show tentative | jq -e '.[].addr_info'; do sleep 0.1; done
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] | .[0]'
hout HOST_ADDR6 ip -j -6 addr show|jq -rM '[.[] | select(.ifname == "__HOST_IFNAME6__").addr_info[] | select(.scope == "global" and .deprecated != true).local] | .[0]'

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@ -116,6 +116,8 @@ iperf3k ns
# Reducing MTU below 1280 deconfigures IPv6, get our address back
guest dhclient -6 -x
guest dhclient -6 __IFNAME__
# Wait for DAD to complete
guest while ip -j -6 addr show tentative | jq -e '.[].addr_info'; do sleep 0.1; done
tl TCP RR latency over IPv4: guest to host
lat -

View file

@ -40,6 +40,9 @@ guest1 while ip -j -6 addr show tentative | jq -e '.[].addr_info'; do sleep 0.1;
guest2 while ip -j -6 addr show tentative | jq -e '.[].addr_info'; do sleep 0.1; done
guest1 /sbin/dhclient -6 __IFNAME1__
guest2 /sbin/dhclient -6 __IFNAME2__
# Wait for DAD to complete on the DHCP address
guest1 while ip -j -6 addr show tentative | jq -e '.[].addr_info'; do sleep 0.1; done
guest2 while ip -j -6 addr show tentative | jq -e '.[].addr_info'; do sleep 0.1; done
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" and .deprecated != true).local] | .[0]'