On Fri, 4 Sep 2020 09:15:20 +0000 Henrik Bjoernlund <henrik.bjoernlund@xxxxxxxxxxxxx> wrote: > Connectivity Fault Management (CFM) is defined in 802.1Q section 12.14. > > Connectivity Fault Management (CFM) comprises capabilities for > detecting, verifying, and isolating connectivity failures in > Virtual Bridged Networks. These capabilities can be used in > networks operated by multiple independent organizations, each > with restricted management access to each other’s equipment. > > CFM functions are partitioned as follows: > — Path discovery > — Fault detection > — Fault verification and isolation > — Fault notification > — Fault recovery > > The primary CFM protocol shims are called Maintenance Points (MPs). > A MP can be either a MEP or a MHF. > The MEP: > -It is the Maintenance association End Point > described in 802.1Q section 19.2. > -It is created on a specific level (1-7) and is assuring > that no CFM frames are passing through this MEP on lower levels. > -It initiates and terminates/validates CFM frames on its level. > -It can only exist on a port that is related to a bridge. > The MHF: > -It is the Maintenance Domain Intermediate Point > (MIP) Half Function (MHF) described in 802.1Q section 19.3. > -It is created on a specific level (1-7). > -It is extracting/injecting certain CFM frame on this level. > -It can only exist on a port that is related to a bridge. > -Currently not supported. > > There are defined the following CFM protocol functions: > -Continuity Check > -Loopback. Currently not supported. > -Linktrace. Currently not supported. > > This CFM component supports create/delete of MEP instances and > configuration of the different CFM protocols. Also status information > can be fetched and delivered through notification due to defect status > change. > > The user interacts with CFM using the 'cfm' user space client program, the > client talks with the kernel using netlink. The kernel will try to offload > the requests to the HW via switchdev API (not implemented yet). > > Any notification emitted by CFM from the kernel can be monitored in user > space by starting 'cfm_server' program. > > Currently this 'cfm' and 'cfm_server' programs are standalone placed in a > cfm repository https://github.com/microchip-ung/cfm but it is considered > to integrate this into 'iproute2'. > > Reviewed-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx> > Signed-off-by: Henrik Bjoernlund <henrik.bjoernlund@xxxxxxxxxxxxx> Could this be done in userspace? It is a control plane protocol. Could it be done by using eBPF? Adding more code in bridge impacts a large number of users of Linux distros. It creates bloat and potential security vulnerabilities.
