162d52dfee
We can make the phc2sys helper not only synchronize a PHC to CLOCK_REALTIME, which is what it currently does, but also CLOCK_REALTIME to a PHC, which is going to be needed in distributed TSN tests. Instead of making the complexity of the arguments passed to phc2sys_start() explode, we can let it figure out the sync direction automatically, based on ptp4l's port states. Towards that goal, pass just the path to the desired ptp4l instance's UNIX domain socket, and remove the $if_name argument (from which it derives the PHC). Also adapt the one caller from the ocelot psfp.sh test. In the case of psfp.sh, phc2sys_start is able to properly figure out that CLOCK_REALTIME is the source clock and swp1's PHC is the destination, because of the way in which ptp4l_start for the UDS_ADDRESS_SWP1 was called: with slave_only=false, so it will always win the BMCA and always become the sync master between itself and $h1. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Motivation ========== One of the nice things about network namespaces is that they allow one to easily create and test complex environments. Unfortunately, these namespaces can not be used with actual switching ASICs, as their ports can not be migrated to other network namespaces (NETIF_F_NETNS_LOCAL) and most of them probably do not support the L1-separation provided by namespaces. However, a similar kind of flexibility can be achieved by using VRFs and by looping the switch ports together. For example: br0 + vrf-h1 | vrf-h2 + +---+----+ + | | | | 192.0.2.1/24 + + + + 192.0.2.2/24 swp1 swp2 swp3 swp4 + + + + | | | | +--------+ +--------+ The VRFs act as lightweight namespaces representing hosts connected to the switch. This approach for testing switch ASICs has several advantages over the traditional method that requires multiple physical machines, to name a few: 1. Only the device under test (DUT) is being tested without noise from other system. 2. Ability to easily provision complex topologies. Testing bridging between 4-ports LAGs or 8-way ECMP requires many physical links that are not always available. With the VRF-based approach one merely needs to loopback more ports. These tests are written with switch ASICs in mind, but they can be run on any Linux box using veth pairs to emulate physical loopbacks. Guidelines for Writing Tests ============================ o Where possible, reuse an existing topology for different tests instead of recreating the same topology. o Tests that use anything but the most trivial topologies should include an ASCII art showing the topology. o Where possible, IPv6 and IPv4 addresses shall conform to RFC 3849 and RFC 5737, respectively. o Where possible, tests shall be written so that they can be reused by multiple topologies and added to lib.sh. o Checks shall be added to lib.sh for any external dependencies. o Code shall be checked using ShellCheck [1] prior to submission. 1. https://www.shellcheck.net/