Hi Eelco, Thanks for working on this, very useful indeed. not a full review, but I have a question about a minor thing.
Eelco Chaudron <[email protected]> writes: > Currently, conntrack in the kernel has an undocumented feature referred > to as NULL SNAT. Basically, when a source port collision is detected > during the commit, the source port will be translated to an ephemeral > port. If there is no collision, no SNAT is performed. > > This patchset documents this behavior and adds a self-test to verify > it's not changing. > > Signed-off-by: Eelco Chaudron <[email protected]> > --- > lib/ovs-actions.xml | 10 ++++++++ > tests/system-kmod-macros.at | 7 ++++++ > tests/system-traffic.at | 45 > ++++++++++++++++++++++++++++++++++++++ > tests/system-userspace-macros.at | 10 ++++++++ > 4 files changed, 72 insertions(+) > > diff --git a/lib/ovs-actions.xml b/lib/ovs-actions.xml > index a2778de4b..a0070e6c6 100644 > --- a/lib/ovs-actions.xml > +++ b/lib/ovs-actions.xml > @@ -1833,6 +1833,16 @@ for <var>i</var> in [1,<var>n_members</var>]: > connection, will behave the same as a bare <code>nat</code>. > </p> > > + <p> > + For SNAT, there is a special case when the <code>src</code> IP > + address is configured as all 0's, i.e., > + <code>nat(src=0.0.0.0)</code>. In this case, when a source port > + collision is detected during the commit, the source port will be > + translated to an ephemeral port. If there is no collision, no > SNAT > + is performed. Note that this is currently only implemented in the > + Linux kernel datapath. > + </p> > + > <p> > Open vSwitch 2.6 introduced <code>nat</code>. Linux 4.6 was the > earliest upstream kernel that implemented <code>ct</code> > support for > diff --git a/tests/system-kmod-macros.at b/tests/system-kmod-macros.at > index 15628a7c6..38bb1c55c 100644 > --- a/tests/system-kmod-macros.at > +++ b/tests/system-kmod-macros.at > @@ -99,6 +99,13 @@ m4_define([CHECK_CONNTRACK_FRAG_OVERLAP], > # > m4_define([CHECK_CONNTRACK_NAT]) > > +# CHECK_CONNTRACK_NULL_SNAT() > +# > +# Perform requirements checks for running conntrack SNAT NULL tests. > +# The kernel always supports NULL SNAT, so no check is needed. > +# > +m4_define([CHECK_CONNTRACK_NULL_SNAT]) > + > # CHECK_CONNTRACK_TIMEOUT() > # > # Perform requirements checks for running conntrack customized timeout tests. > diff --git a/tests/system-traffic.at b/tests/system-traffic.at > index fb5b9a36d..1be425bb4 100644 > --- a/tests/system-traffic.at > +++ b/tests/system-traffic.at > @@ -4433,6 +4433,51 @@ > tcp,orig=(src=10.1.1.1,dst=10.1.1.2,sport=<cleared>,dport=<cleared>),reply=(src= > OVS_TRAFFIC_VSWITCHD_STOP > AT_CLEANUP > > + > +AT_SETUP([conntrack - NULL SNAT]) > +AT_SKIP_IF([test $HAVE_NC = no]) > +CHECK_CONNTRACK() > +CHECK_CONNTRACK_NULL_SNAT() > +OVS_TRAFFIC_VSWITCHD_START() > + > +ADD_NAMESPACES(at_ns0, at_ns1) > +ADD_VETH(p0, at_ns0, br0, "10.1.1.1/24") > +ADD_VETH(p1, at_ns1, br0, "10.1.1.2/24") > +NS_CHECK_EXEC([at_ns0], [ip route add 172.1.1.0/24 via 10.1.1.2]) > + > +OVS_START_L7([at_ns1], [http]) > + I noticed you use nc clients, is there any specific reason you preferred httpd over something like: NETNS_DAEMONIZE([at_ns1], [nc -l -k 80 > /dev/null], [nc0.pid]) > +AT_DATA([flows.txt], [dnl > +table=0,priority=30,ct_state=-trk,ip,action=ct(table=0) > +table=0,priority=20,ip,nw_dst=10.1.1.0/24,actions=ct(commit,nat(src=0.0.0.0),table=10) > +table=0,priority=20,ip,nw_dst=172.1.1.2,actions=ct(commit,nat(dst=10.1.1.2),table=10) > +table=0,priority=10,arp,action=normal > +table=0,priority=1,action=drop > +table=10,priority=20,ct_state=+rpl,ip,nw_dst=10.1.1.0/24 > actions=ct(table=20,nat) > +table=10,priority=10,ip,nw_dst=10.1.1.0/24 actions=resubmit(,20) > +table=20,priority=10,ip,nw_dst=10.1.1.1,action=1 > +table=20,priority=10,ip,nw_dst=10.1.1.2,action=2 > +]) > +AT_CHECK([ovs-ofctl --bundle add-flows br0 flows.txt]) > + > +dnl - Test to make sure src nat is NOT done when not needed > +NS_CHECK_EXEC([at_ns0], [echo "TEST" | nc -p 30000 10.1.1.2 80 > nc-1.log]) > +AT_CHECK([ovs-appctl dpctl/dump-conntrack | grep "orig=.src=10\.1\.1\.1,"], > [0], [dnl > +tcp,orig=(src=10.1.1.1,dst=10.1.1.2,sport=30000,dport=80),reply=(src=10.1.1.2,dst=10.1.1.1,sport=80,dport=30000),protoinfo=(state=TIME_WAIT) > +]) > + > +dnl - Test to make sure src nat is done when needed > +NS_CHECK_EXEC([at_ns0], [echo "TEST2" | nc -p 30001 172.1.1.2 80 > nc-2.log]) > +NS_CHECK_EXEC([at_ns0], [echo "TEST3" | nc -p 30001 10.1.1.2 80 > nc-3.log]) > +AT_CHECK([ovs-appctl dpctl/dump-conntrack | grep 30001 | grep > "orig=.src=10\.1\.1\.1," | sed -e 's/port=30001/port=<clnt_s_port>/g' -e > 's/sport=80,dport=[[0-9]]\+/sport=80,dport=<rnd_port>/g' | sort], [0], [dnl > +tcp,orig=(src=10.1.1.1,dst=10.1.1.2,sport=<clnt_s_port>,dport=80),reply=(src=10.1.1.2,dst=10.1.1.1,sport=80,dport=<rnd_port>),protoinfo=(state=TIME_WAIT) > +tcp,orig=(src=10.1.1.1,dst=172.1.1.2,sport=<clnt_s_port>,dport=80),reply=(src=10.1.1.2,dst=10.1.1.1,sport=80,dport=<clnt_s_port>),protoinfo=(state=TIME_WAIT) > +]) > + > +OVS_TRAFFIC_VSWITCHD_STOP > +AT_CLEANUP > + > + > AT_SETUP([conntrack - simple DNAT]) > CHECK_CONNTRACK() > CHECK_CONNTRACK_NAT() > diff --git a/tests/system-userspace-macros.at > b/tests/system-userspace-macros.at > index 34f82cee3..71acc8618 100644 > --- a/tests/system-userspace-macros.at > +++ b/tests/system-userspace-macros.at > @@ -96,6 +96,16 @@ m4_define([CHECK_CONNTRACK_FRAG_OVERLAP]) > # > m4_define([CHECK_CONNTRACK_NAT]) > > +# CHECK_CONNTRACK_NULL_SNAT() > +# > +# Perform requirements checks for running conntrack SNAT NULL tests. > +# The userspace datapath does not support NULL SNAT. > +# > +m4_define([CHECK_CONNTRACK_NULL_SNAT], > +[ > + AT_SKIP_IF([:]) > +]) > + > # CHECK_CONNTRACK_TIMEOUT() > # > # Perform requirements checks for running conntrack customized timeout tests. _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
