$ find * -type f |xargs perl contrib/scripts/spdx.pl
  $ git rm contrib/scripts/spdx.pl

IP addresses, routes, TC and QDiscs are all tied to a certain interface.
So when NetworkManager manages an interface, it can be confident that
all related entires should be managed, deleted and modified by NetworkManager.

Routing policy rules are global. For that we have NMPRulesManager which
keeps track of whether NetworkManager owns a rule. This allows multiple
connection profiles to specify the same rule, and NMPRulesManager can
consolidate this information to know whether to add or remove the rule.

NMPRulesManager would also support to explicitly block a rule by
tracking it with negative priority. However that is still unused at
the moment. All that devices do is to add rules (track with positive
priority) and remove them (untrack) once the profile gets deactivated.

As rules are not exclusively owned by NetworkManager, NetworkManager
tries not to interfere with rules that it knows nothing about. That
means in particular, when NetworkManager starts it will "weakly track"
all rules that are present. "weakly track" is mostly interesting for two
cases:

  - when NMPRulesManager had the same rule explicitly tracked (added) by a
    device, then deactivating the device will leave the rule in place.

  - when NMPRulesManager had the same rule explicitly blocked (tracked
    with negative priority), then it would restore the rule when that
    block gets removed (as said, currently nobody actually does this).

Note that when restarting NetworkManager, then the device may stay and
the rules kept. However after restart, NetworkManager no longer knows
that it previously added this route, so it would weakly track it and
never remove them again.

That is a problem. Avoid that, by whenever explicitly tracking a rule we
also make sure to no longer weakly track it. Most likely this rule was
indeed previously managed by NetworkManager. If this was really a rule
added by externally, then the user really should choose distinct
rule priorities to avoid such conflicts altogether.

We no longer add these. If you use Emacs, configure it yourself.

Also, due to our "smart-tab" usage the editor anyway does a subpar
job handling our tabs. However, on the upside every user can choose
whatever tab-width he/she prefers. If "smart-tabs" are used properly
(like we do), every tab-width will work.

No manual changes, just ran commands:

    F=($(git grep -l -e '-\*-'))
    sed '1 { /\/\* *-\*-  *[mM]ode.*\*\/$/d }'     -i "${F[@]}"
    sed '1,4 { /^\(#\|--\|dnl\) *-\*- [mM]ode/d }' -i "${F[@]}"

Check remaining lines with:

    git grep -e '-\*-'

The ultimate purpose of this is to cleanup our files and eventually use
SPDX license identifiers. For that, first get rid of the boilerplate lines.

nmtst_get_rand_int() was originally named that way, because it
calls g_rand_int(). But I think if a function returns an uint32, it
should also be named that way.

Rename.

On Ubuntu 14.04 kernel (4.4.0-146-generic, x86_64) this easily causes
test failures:

    make -j 8 src/platform/tests/test-route-linux \
    && while true; do \
        NMTST_SEED_RANDOM= ./tools/run-nm-test.sh src/platform/tests/test-route-linux -p /route/rule \
        || break; \
    done

outputs:

    ...
    /route/rule/1:
    nmtst: initialize nmtst_get_rand() with NMTST_SEED_RAND=22892021
    OK
    /route/rule/2: >>> failing...
    >>> no fuzzy match between: [routing-rule,0x205ab30,1,+alive,+visible; [6] 0: from all suppress_prefixlen 8 none]
    >>>                    and: [routing-rule,0x205c0c0,1,+alive,+visible; [6] 0: from all suppress_prefixlen -1579099242 none]
    **
    test:ERROR:src/platform/tests/test-route.c:1695:test_rule: code should not be reached

All that setting track-default does, is calling nmp_rules_manager_track_default()
when the rules are first accessed.

That is not right API. Since nmp_rules_manager_track_default() is already public
API (good), every caller that wishes this behavior should track these routes explicitly.

  # NetworkManager-MESSAGE: <warn>  [1553100541.6609] platform-linux: do-add-rule: failure 17 (File exists)
  >>> failing... errno=-17, rule=[routing-rule,0xe9c540,1,+alive,+visible; [6] 4294967295: from all suppress_prefixlen 3 none goto-target 2955537847]
  0:      from all to 73.165.79.8/2 iif nm-test-device 178
  0:      from all 109
  0:      from all tos 0x13 lookup 10004 suppress_prefixlength 0 none
  0:      from all none
  4294967295:     not from all none

  test:ERROR:../src/platform/tests/test-route.c:1607:test_rule: assertion failed (r == 0): (-17 == 0)

Possibly fixed by https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c8f4e6dc30996bff806285730a0bb4e714d3d52