Split ipvrf_identify into arg processing and a function that does the
actual cgroup file parsing. The latter function is used in a follow
on patch.
In the process, convert the reading of the cgroups file to use fopen
and fgets just in case the file ever grows beyond 4k. Move printing
of any error message and the vrf name to the caller of the new
vrf_identify.
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Move the hint about CGROUP_BPF enabled to prog_load failure since
it fails before the attach. Update the existing error message to
print to stderr.
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
'ip vrf' follows the user semnatics established by 'ip netns'.
The 'ip vrf' subcommand supports 3 usages:
1. Run a command against a given vrf:
ip vrf exec NAME CMD
Uses the recently committed cgroup/sock BPF option. vrf directory
is added to cgroup2 mount. Individual vrfs are created under it. BPF
filter attached to vrf/NAME cgroup2 to set sk_bound_dev_if to the VRF
device index. From there the current process (ip's pid) is addded to
the cgroups.proc file and the given command is exected. In doing so
all AF_INET/AF_INET6 (ipv4/ipv6) sockets are automatically bound to
the VRF domain.
The association is inherited parent to child allowing the command to
be a shell from which other commands are run relative to the VRF.
2. Show the VRF a process is bound to:
ip vrf id
This command essentially looks at /proc/pid/cgroup for a "::/vrf/"
entry with the VRF name following.
3. Show process ids bound to a VRF
ip vrf pids NAME
This command dumps the file MNT/vrf/NAME/cgroup.procs since that file
shows the process ids in the particular vrf cgroup.
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
David Ahern
Stephen Hemminger