LU-14288 lnet: Introduce nidmasks

LU-14288 lnet: Introduce nidmasks

A nidmask is like a netmask, except it applies to IPv4 or IPv6 LNet
NIDs.

Nidmasks use the existing nidlist infrastructure so any caller of
cfs_parse_nidlist() can include a nidmask in the argument and match
NIDs against it using cfs_match_nid(), or convert it back to a string
with cfs_print_nidlist().

For example, "192.168.1.1@tcp/24" is equivalent to the nidrange
"192.168.1.[1-254]@tcp", and "2001::1@tcp/126" is equivalent to
"2001::@tcp 2001::1@tcp 2001::2@tcp 2001::3@tcp".

cfs_parse_nidrange() is modified to treat an IPv6 address as
equivalent to a netmask with prefix length of /128. Thus,
cfs_parse_nidlist() can now be used with lists of IPv6 addresses.

The user and kernel space implementations of cfs_parse_nidlist(),
et. al. have been modified to more closely match each other. Namely,
char * is used instead of the struct cfs_lstr and a length argument
is added to the kernel space cfs_parse_nidlist. Callers are adjusted
accordingly.

conf-sanity.sh/test_43a is modified to generate nidmasks that contain
the client's NID and verify that this is handled correctly when
nosquash_nids is set to the nidmask.

lnetctl debug nidlist command is added to facilitate testing of the
userspace code.

Test-Parameters: trivial testlist=conf-sanity env=ONLY=43a
Test-Parameters: testlist=conf-sanity env=ONLY=43a,FORCE_LARGE_NID=true,LOAD_MODULES_REMOTE=true
Signed-off-by: Chris Horn <chris.horn@hpe.com>
Change-Id: Id9d0bc6f4f8b977591f0b6f88bda46ae03cb58d5
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/55922
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Neil Brown <neilb@suse.de>
Reviewed-by: Serguei Smirnov <ssmirnov@whamcloud.com>