Re: [PATCH net] ipv6: fix the check before getting the cookie in rt6_get_cookie

[Xin Long <lucien.xin@gmail.com>]

On Thu, Jun 6, 2019 at 11:35 PM David Ahern <dsahern@gmail.com> wrote:
>
> On 6/2/19 5:10 AM, Xin Long wrote:
> > In Jianlin's testing, netperf was broken with 'Connection reset by peer',
> > as the cookie check failed in rt6_check() and ip6_dst_check() always
> > returned NULL.
>
> Any particular test or setup that is causing the reset? I do not see
> that problem in general.
>
by running the script below, netperf ends up with:

Connection reset by peer
netperf: remote error 104


--------------------------

#!/bin/bash

ip netns add client
ip netns add server
ip netns add route

ip link add veth0_c type veth peer name veth0_cr
ip link add veth0_s type veth peer name veth0_sr
ip link set veth0_c netns client
ip link set veth0_s netns server
ip link set veth0_cr netns route
ip link set veth0_sr netns route

ip netns exec client ip link set lo up
ip netns exec client ip link set veth0_c up

ip netns exec server ip link set lo up
ip netns exec server ip link set veth0_s up

ip netns exec route ip link set lo up
ip netns exec route ip link set veth0_cr up
ip netns exec route ip link set veth0_sr up

ip netns exec client ip addr add 2000::1/64 dev veth0_c
ip netns exec client ip addr add 10.10.0.1/24 dev veth0_c
ip netns exec route ip addr add 2000::a/64 dev veth0_cr
ip netns exec route ip addr add 10.10.0.254/24 dev veth0_cr

ip netns exec server ip addr add 2001::1/64 dev veth0_s
ip netns exec server ip addr add 10.10.1.1/24 dev veth0_s
ip netns exec route ip addr add 2001::a/64 dev veth0_sr
ip netns exec route ip addr add 10.10.1.254/24 dev veth0_sr

ip netns exec client ip route add default via 10.10.0.254
ip netns exec client ip -6 route add default via 2000::a

ip netns exec server ip route add default via 10.10.1.254
ip netns exec server ip -6 route add default via 2001::a

ip netns exec route sysctl -w net.ipv4.conf.all.forwarding=1
ip netns exec route sysctl -w net.ipv6.conf.all.forwarding=1

ip netns exec client ping 10.10.1.1 -c 2
ip netns exec client ping6 2001::1 -c 2

ip netns exec route ip link set veth0_sr mtu 1400
ip netns exec server ip link set veth0_s mtu 1400

ip netns exec server netserver -d

ip netns exec client ping6 2001::1 -c 1 -s 1400 -M do
ip netns exec client ip route get 2001::1

ip netns exec client ip link set veth0_c mtu 1300
ip netns exec client ip route get 2001::1

ip netns exec client ip link set veth0_c mtu 1600
ip netns exec client ip route get 2001::1

ip netns exec client ping6 2001::1 -c 1 -s 1400 -M do
ip netns exec client ip route get 2001::1

ip netns exec client netperf -6 -H 2001::1 -t SCTP_STREAM -l 30 -- -m 16k &
#ip netns exec client netperf -6 -H 2001::1 -t TCP_STREAM -l 30 -- -m 16k &
#ip netns exec client netperf -6 -H 2001::1 -t UDP_STREAM -l 30 -- -R 1 &
pid=$!

for i in `seq 1 5`
do
ip netns exec client ip link set veth0_c mtu 1300
sleep 1
ip netns exec client ip link set veth0_c mtu 1600
sleep 1
done

wait $pid