Fix /proc/net/route requirement that causes errors on FreeBSD #1638

kawaiivoldemort · 2019-09-18T15:57:29Z

Description

This is a fix for Issue #1479).

What it does is:

Instead of searching the linux specific /proc/net/route in wireserver_route_exists in dhcp.py, it calls the osutil.get_list_of_routes API and checks if the route destination matches the KNOWN_WIRESERVER_IP
It then defines various route related functions in osutil/freebsd.py so that this works on FreeBSD
One of these functions parses netstat -rn and creates RouteEntry objects that look similar enough to the Linux ones for the rest of the code to work

Issue #1479

PR information

The title of the PR is clear and informative.
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Except for special cases involving multiple contributors, the PR is started from a fork of the main repository, not a branch.
If applicable, the PR references the bug/issue that it fixes in the description.
New Unit tests were added for the changes made and Travis.CI is passing.

Quality of Code and Contribution Guidelines

I have read the contribution guidelines.

This change is

msftclas · 2019-09-18T15:57:44Z

All CLA requirements met.

to build_route_list

codecov · 2019-09-19T11:04:36Z

Codecov Report

❗ No coverage uploaded for pull request base (develop@0105f5f). Click here to learn what that means.
The diff coverage is 65.78%.

@@            Coverage Diff             @@
##             develop    #1638   +/-   ##
==========================================
  Coverage           ?   67.19%           
==========================================
  Files              ?       80           
  Lines              ?    11440           
  Branches           ?     1608           
==========================================
  Hits               ?     7687           
  Misses             ?     3420           
  Partials           ?      333

Impacted Files	Coverage Δ
azurelinuxagent/common/dhcp.py	`30.37% <100%> (ø)`
azurelinuxagent/common/osutil/freebsd.py	`42.67% <65.33%> (ø)`

Continue to review full report at Codecov.

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- Moved route conversion code from read_route_table to build_route_list - Fixed some typos - Fixed some routes being ignored

…to develop

kawaiivoldemort · 2019-09-19T12:44:03Z

1ee6e01 is just a squish of all the other commits. It has all the changes.

larohra

Thank you for your contribution @onenachi. Could you please add some test cases for the changes in freebsd.py file? We have a test file \tests\common\osutil\test_freebsd.py where you can add the specific tests for your changes to improve the code coverage.

I've also initiated a run from our automated end-to-end testing just to ensure the changes are not breaking anything.

Apart from that the changes look good to me.

larohra · 2019-10-04T17:49:15Z

tests/common/osutil/test_freebsd.py

@@ -29,6 +31,103 @@ def tearDown(self):
    def test_get_dhcp_pid_should_return_a_list_of_pids(self):
        osutil_get_dhcp_pid_should_return_a_list_of_pids(self, FreeBSDOSUtil())

+    def test_empty_proc_net_route(self):


Thank you for adding the tests 👍

larohra

Left some comments around refactoring and exception handling.

larohra · 2019-10-04T19:23:59Z

azurelinuxagent/common/osutil/freebsd.py

+            return linux_style_route_file
+        netstat_output = netstat_output[3:]
+        # Parse the Netstat -RN header line
+        n_columns = 0


Could you add a comment with a sample output of netstat -rn is to make it easier for the reader to understand the parsing logic

Exmples added as requested in 10819af

larohra · 2019-10-04T19:27:48Z

azurelinuxagent/common/osutil/freebsd.py

+
+        :return: Entries in the route priority table from `netstat -rn`
+        :rtype: list(str)
+        """


Could you please add an example of how the netstat -rn output differs with the linux based proc/net/route header just to make sure what this function is parsing

Exmples added as requested in 10819af

- refactored it into meaningful subfunctions - modified the function documentation to make it more understandable - added examples to the function documentation

larohra

@narrieta this LGTM, can you please take a look

narrieta · 2019-10-08T20:17:27Z

azurelinuxagent/common/dhcp.py

-            if os.path.exists(route_file) and \
-                    KNOWN_WIRESERVER_IP_ENTRY in open(route_file).read():
+            route_table = self.osutil.read_route_table()
+            if any([(KNOWN_WIRESERVER_IP_ENTRY in route) for route in route_table]):


In the original code there was a check for exists(route_file); if it was false, we would output a warning.
In the new code this would be reported as an error.

I'm not sure how to work around this. read_route_table will log an error by default and then return an empty list if /proc/net/route doesn't exist.

The only thing it guarantees is not to raise an exception.

Im not sure changing that function would be appropriate. I do think using that function would be appropriate since checking route is clearly a platform specific task.

I also do think that this is an edge case and not really an issue as it will only log an error on systems without /proc/net/route (non Linux systems) which have not overridden that function with their own osutil (so now, neither Linux nor FreeBSD).

narrieta

requestion 1 small change, otherwise looks good

narrieta · 2019-10-10T16:25:34Z

azurelinuxagent/common/osutil/freebsd.py

+            :rtype: list(dict)
+            """
+            cmd = "netstat -rn -f inet"
+            ret, output = shellutil.run_get_output(cmd)


we are deprecating shellutil.run_get_output in favor of shellutil.run_command, could you change this?

Done with a0112e2 and 72bddb7

narrieta · 2019-10-16T16:52:11Z

azurelinuxagent/common/osutil/freebsd.py

+            :rtype: list(dict)
+            """
+            cmd = "netstat -rn -f inet"
+            output = shellutil.run_command(cmd, log_error=True)


thank you for the update.

run_command sets shell=False when invoking subprocess.Popen, so the command needs to be passed as an array of strings; see, for example https://github.com/Azure/WALinuxAgent/blob/develop/azurelinuxagent/common/utils/cryptutil.py#L55

Also, please be sure to tests this end-to-end on your side. Our test infrastructure does not validate FreeBSD.

Thanks

Fixed in 08ba686

Tested in FreeBSD 11.2 on Azure:

Route table is read successfully.

Sorry about that.

narrieta · 2019-10-21T18:19:50Z

LGTM; running automation - will approve and merge after that

narrieta · 2019-10-23T15:27:30Z

Automation OK

narrieta

Thank you!

Azure/WALinuxAgent#1638 - Update WWW to where the code exists - Switch to use Python 3 to match the ports' default to avoid some subprocess invoking issues Approved by: Wei Hu <weh@microsoft.com> (maintainer, implicitly) Sponsored by: The FreeBSD Foundation git-svn-id: svn+ssh://svn.freebsd.org/ports/head@517374 35697150-7ecd-e111-bb59-0022644237b5

Azure/WALinuxAgent#1638 - Update WWW to where the code exists - Switch to use Python 3 to match the ports' default to avoid some subprocess invoking issues Approved by: Wei Hu <weh@microsoft.com> (maintainer, implicitly) Sponsored by: The FreeBSD Foundation

Azure/WALinuxAgent#1638 - Update WWW to where the code exists - Switch to use Python 3 to match the ports' default to avoid some subprocess invoking issues Approved by: Wei Hu <weh@microsoft.com> (maintainer, implicitly) Sponsored by: The FreeBSD Foundation git-svn-id: svn+ssh://svn.freebsd.org/ports/head@517374 35697150-7ecd-e111-bb59-0022644237b5

Azure/WALinuxAgent#1638 - Update WWW to where the code exists - Switch to use Python 3 to match the ports' default to avoid some subprocess invoking issues Approved by: Wei Hu <weh@microsoft.com> (maintainer, implicitly) Sponsored by: The FreeBSD Foundation

- Update to 2.2.45 (pre-release) to pull in the requried fix Azure/WALinuxAgent#1638 - Update WWW to where the code exists - Switch to use Python 3 to match the ports' default to avoid some subprocess invoking issues Approved by: Wei Hu <weh@microsoft.com> (maintainer, implicitly) Sponsored by: The FreeBSD Foundation Approved by: ports-secteam (blanket(s): bugfix release)

Azure/WALinuxAgent#1638 - Update WWW to where the code exists - Switch to use Python 3 to match the ports' default to avoid some subprocess invoking issues Approved by: Wei Hu <weh@microsoft.com> (maintainer, implicitly) Sponsored by: The FreeBSD Foundation

- Fix /proc/net/route requirement on FreeBSD

db21ecf

kawaiivoldemort requested review from larohra, narrieta, pgombar and vrdmr as code owners September 18, 2019 15:57

kawaiivoldemort changed the title ~~Fix /proc/net/route requirement on FreeBSD (to fix https://github.com/Azure/WALinuxAgent/issues/1479)~~ Fix /proc/net/route requirement that causes errors on FreeBSD Sep 18, 2019

Moved route conversion code from read_route_table

c98c917

to build_route_list

Nachiketa Ramesh added 4 commits September 19, 2019 17:20

- Fixed some typos

ceeb1b1

- Fixed some routes being ignored

3b7b987

- Fix /proc/net/route requirement on FreeBSD

1ee6e01

- Moved route conversion code from read_route_table to build_route_list - Fixed some typos - Fixed some routes being ignored

Merge branch 'develop' of https://github.com/onenachi/WALinuxAgent in…

3d17625

…to develop

vrdmr assigned larohra Sep 26, 2019

larohra suggested changes Oct 2, 2019

View reviewed changes

kawaiivoldemort added 14 commits October 3, 2019 17:44

- Added Unit Tests

8a84b14

- Fixed the patch

a245b2d

- Fixed using osutil instead of FreeBSD osutil

12aaffb

- Patched the right function

9e24775

- Fixed the route table

2e5eee2

- fixed zero length field name in python 2.6

92a1fd7

- Fixed the routes in the valid test

8f221c4

- More fixes for valid routes

9e4b64a

- Fixed some IP parsing

6ae71f7

- Fixed the parsing of the ipv4 addresses

b086c46

- Fixed some typos (comma placement and params)

766815b

- FIxed a typo

f79cf03

- Ordering of netmask check

db17060

- Changed subnet in test

c62829a

larohra reviewed Oct 4, 2019

View reviewed changes

larohra suggested changes Oct 4, 2019

View reviewed changes

- added exception handling to read_route_table in freebsd.py

515b672

larohra reviewed Oct 4, 2019

View reviewed changes

Nachiketa Ramesh added 2 commits October 7, 2019 16:58

- maked netstat parsing code more readable

10819af

- refactored it into meaningful subfunctions - modified the function documentation to make it more understandable - added examples to the function documentation

- Fixed the FreeBSD tests

e9d7a64

kawaiivoldemort requested a review from larohra October 7, 2019 11:37

larohra reviewed Oct 7, 2019

View reviewed changes

narrieta reviewed Oct 8, 2019

View reviewed changes

narrieta requested changes Oct 10, 2019

View reviewed changes

Nachiketa Ramesh added 2 commits October 15, 2019 14:47

moved from run_get_output to run_command in _get_netstat_rn_ipv4_routes

a0112e2

- Fixed the freebsd tests to patch run_command

72bddb7

kawaiivoldemort requested a review from narrieta October 16, 2019 09:55

narrieta reviewed Oct 16, 2019

View reviewed changes

- Fixed run_command in freebsd.py

08ba686

kawaiivoldemort requested a review from narrieta October 21, 2019 03:29

narrieta approved these changes Oct 23, 2019

View reviewed changes

larohra approved these changes Oct 23, 2019

View reviewed changes

narrieta merged commit f2af566 into Azure:develop Oct 23, 2019

SystemsUK mentioned this pull request Jan 22, 2020

Deprovision RHEL 7.7 using 2.2.45 loops with ERROR Daemon /proc/net/route contains no routes #1764

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Fix /proc/net/route requirement that causes errors on FreeBSD #1638

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Fix /proc/net/route requirement that causes errors on FreeBSD #1638

Fix /proc/net/route requirement that causes errors on FreeBSD #1638

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