Most of the content here is the result of the [the weekly IRC discussions](/Meetings).

There are two primary developer channels:

* **[openvpn-devel mailinglist](https://sourceforge.net/p/openvpn/mailman/openvpn-devel/)**: primary communication channel, subscription required

* **#openvpn-devel (at) libera.chat:** used for generic development discussions and the weekly IRC meetings (requires libera.chat registration)

The basic development process we follow is outlined in the diagram. So, the daily development process works like this:

* All patches must be eventually sent to "openvpn-devel" mailing list for review. The subject should preferably be prefixed with **[PATCH]**

* All patches need to be reviewed and accepted (ACK). The ACK process is logically split into two (see below).

* Regular developers can push to [Gerrit](https://gerrit.openvpn.net) and have their patches reviewed there before the final version is sent to the openvpn-devel mailing list.

* All accepted patches go to the OpenVPN **master** branch (Git)

The author must send patches to the devel mailing list. This is so to open up for a public discussion of the changes, and to allow the ACK process to work. All patches going into the tree will contain explicit Acked-by: references, to document who gave the approval.

* You can see a list of replies to a patch including the ACKs in [Gerrit](https://gerrit.openvpn.net).

* Patches sent *directly* to a development tree maintainer will be rejected

* GitHub pull requests can be useful with large patchsets, or if you want to gauge interest in your patch. The final patch needs to go to "openvpn-devel" mailing list, however.

In the [IRC meeting](http://thread.gmane.org/gmane.network.openvpn.devel/3571) on 22nd Apr 2010 it was agreed that placeholder bug reports should be filed even for bugs which are fixed before anyone reports them as bugs. This allows users to check if the bugs they encounter have already been fixed.

Prior to making a release the following happens:

* Features to include will be merged to the **master** branch.

* Features will be stabilized until they don't change much.

* Beta release will be published based on latest **master** (to get people to _really_ test the code)

* This should have most features for the release included, and as such be mostly testing and bug fixing. However, new features could still change as much as needed and old features could be changed if absolutely needed.

* RC release will published based on latest **master**

* This should focus only on stabilization and bug fixes. At this point we know for sure which features should be included. Only in worst cases should a feature taken out, e.g. if it really is horrendous to stability.

* Once the code-base is deemed stable enough, an official release will be made

* Once there is need to use the **master** branch for the next release version (i.e. new features should be merged that will not go into the current release), a **release/2.x** branch will branched off. This might happen at any point during the Beta phase but if there is no need could also be delayed until after the official release.

The project currently aims for a 2 year release cycle. Shorter release cycles don't seem achievable with the current level of test automation.

Feature removal process is another workflow which also goes through the general workflow to get a feature removed. This process serves two purposes:

* Maintain backwards compatibility and minimize the impact of feature removal (for users)

* Keeping the codebase clean and understandable (for developers)

All patches needs to receive an ACK (Acknowledged) before being accepted in to the Git repository. To encourage participation from non-developers the ACK is split into two parts:

* *"This patch does the right thing ACK"*. Also known as *feature ACK*. One does not have to be a developer to give this ACK.

* *"This patch does the thing (it does) right"*. Also known as *code quality ACK*. People who understand the code can give this.

Note that both ACKs can be given by a single person.

A patch has to get both ACKs to be included into the development tree. The ACK process is used to ensure that only useful and high-quality code gets into OpenVPN. Hopefully that will make it easier for those who don't feel they are "good enough" developers to try to send patches anyway.

This whole review process is to give and receive feedback, where we as a community can help making OpenVPN better - together. For example, the more experienced developers can share their advice to those who are less experienced. Those being less experienced can share their understanding of the code as well, which might shed some light to issues or solutions which are better. Non-developers can also participate by sharing their expertise on OpenVPN in general by giving feature ACKs (NACKs) when applicable. This way everyone can learn something and hopefully even get wiser.

To explain the Signed-off-by and Acked-by process a bit further. In git you have two "data fields" which are populated automatically when commits are done, author and committer. The committer will be the one who applies patches from the mailing list or the one doing commits to a tree which are fetched via the remote access features in git.

Then you have the author field which is usually present in the patch file itself. This field might be missing if *git format-patch* has not been used to create the patch file sent to the mailing list. In these cases, it is expected that the author of the patch is the same as the sender - unless the commit message in the patch indicates something else.

If the author information is present, the sender field will be treated differently as well, in those cases where someone sends a patch on behalf of somebody else.

So to summarize, we track these fields almost automatically:

* author - information about the person who *wrote* the patch

* sender - information about who *sent / forwarded* the patch for inclusion

* committer - information about who *applied* the patch to the git tree

When a patch author sends his patch to somewhere, he should make sure it contains a `Signed-off-by: {Full name} <email@example.com>` line in the commit text. This is to officially announce that declare that this patch is ready for further processing. When doing git commits, you can add this indication automatically by doing *git commit -s* (or *--signed-off*).

The one who receives the patch and finds it good to go even further (if you want to do some kind of "internal" review before sending it further to the public) will add his/hers *Signed-off-by* reference as well when sending further again. This way we can track who has been looking at the patch. And the more people who have eye-balled the patch and added their *Signed-off* line to the patch, the better! By doing so, the reviewer indicates that the patch is good.

Before it goes into the tree, a final "Acked-by:" note is added, indicating who accepted it for inclusion into the tree,

Lets say John Doe writes a patch, sends it to Jane Doe and she sends it

Bob Boss for inclusion. The process would be something like this:

**When Bob Boss ACKs the patch**, the final commit to be found in the

source code repository will be:

The Acked-by: can be the one who does the final commit to the source code repository, but it can also be someone who doesn't do the final commit. The last Signed-off-by should normally be the person who does the final commit. This is usually the person who "touched" the patch by adding the Acked-by line(s).

However, you should not see any commits which are written by (author) and Acked-by by the same person. Then the process has failed to give a qualified review.

You may ask why we have this "bureaucracy" (which is a fair question!). It is simply to keep all who send in patches, those who review them and finally accept them into the source code repository more accountable for their work. This process will document each accepted patch and give an indication that it has been through a certain set of reviews. This is to ensure that we don't accept bad code easily into the source code repository. This is just to keep this project as transparent and open as possible.

The way OpenVPN project handles security issues was discussed and agreed upon in the IRC meeting on [15th July 2010](http://thread.gmane.org/gmane.network.openvpn.devel/3841). The goal is to disclose security issues in 3 weeks - or less, if a fix is ready. If a fix is not ready in 3 weeks the issue should be disclosed nevertheless and provide workarounds (if any) to users and then fix the issue a.s.a.p. Also, *all* security issues - whether they're theoretical or being exploited - should be fixed. Also agreed that our users should be informed about vulnerabilities in external software OpenVPN depends on (e.g. OpenSSL). This will be done after developers of the external software have already disclosed the vulnerability.

The OpenVPN project has an instance of the [Gerrit code review tool](https://gerrit-review.googlesource.com/), hosted at https://gerrit.openvpn.net/. This is intended to aid in the submission and review of bigger patches or patch series (i.e. patches that do depend on each other). Gerrit allows to

* Track review comments on a patch

* Review changes between different revisions of a patch

* Get test builds for patches

The use of Gerrit is encouraged over using [GitHub Pull-Requests](https://github.com/OpenVPN/openvpn/pulls). The main difference is that our development workflow is currently patch orientated. Even when you submit a patch series, each patch needs to stand on its own, and produce a working build. Each patch will be merged individually. Gerrit supports this model, while Pull Requests like in !GitHub or similar products are more branch-oriented.

Existing codebase uses an Allman based style. Please visit the [Code Style](/Development/CodeStyle) wikipage for more details.

All *patches*, regardless of their type need to be created following a few rules:

* Must be sent as unified diff (diff -u) or preferably generated by *git format-patch*

* Patches must have a short but descriptive one-line summary of the change, followed by a more descriptive text explaining in plain English why and how the patch is written. This description should *not* be too technical, as the patch itself will reveal technical details. More on [writing good commit messages here](http://who-t.blogspot.com/2009/12/on-commit-messages.html)

* Patches should contain a `Signed-off-by:` line at the end (*git commit --signoff*). If missing, it will be added with the sender of the patch as the signed-off person.

* Patches must apply cleanly, without merge conflicts. Please state which code base the patch is written against. If based on the git tree, please state which branch it is to be applied to.

* Everyone who has contributed to this patch should be mentioned out of courtesy and respect to all contributors and helpers on the way. If suitable valid e-mail address should be used, preferably in addition with full name.

All *code patches* need to meet certain generic quality criteria before being accepted:

* All code should be useful and beneficial for several OpenVPN users. This way we avoid spoiling the code base with features which is only requested for very special conditions.

* New features need to make use of #ifdef's so that they can be disabled at compile-time. This is to enable better support for embedded systems and to track which code belongs to which feature.

* Patch needs to respect our [Code Style](/Development/CodeStyle) to keep the code base understandable and maintainable.

Also note that the *documentation* (e.g. man pages) need to be updated, if

* New functionality has been introduced

* Old functionality has changed

* Functionality has been removed

Patches to *shell scripts* such as those in *easy-rsa* should be POSIX-compliant for portability reasons. If the existing scripts don't fulfill this requirement, please provide a patch :). He're are a few links to relevant resources:

* [Bashism - Greg's Wiki](http://mywiki.wooledge.org/Bashism)

* [Checkbashisms](http://sourceforge.net/projects/checkbaskisms): a tool to check for "Bashisms". Also included in !Debian/Ubuntu "devscripts" package.

* [DASH](http://gondor.apana.org.au/~herbert/dash): a minimal shell with "POSIX-compliant features only", probably useful for testing

Contents of this section are now [here](/Pages/CodeRepositories).

There is some additional infrastructure available for developers that are part of the core development team.

To use the internal infrastructure you first need VPN access to it. If you think you should have access you should know who to ask for your config.

Some of our CI builds happen on our Buildbot instance. Failed builds will be documented with mails to the [openvpn-builds mailinglist](https://sourceforge.net/p/openvpn/mailman/openvpn-builds/) mailing list, but if you have access to the Community VPN you can also directly access the web interface.

This is also integrated with out Gerrit server, but only changes submitted by whitelisted developer accounts will trigger builds.

There is a HTTP Proxy available at `http://community-test-proxy.openvpn.in:8080`. You need to be logged into the Community VPN to be able to access it. It is intended to be used for openvpn tests only.

There is a Sock5 Proxy available at `community-test-proxy.openvpn.in:1080`. It allows both TCP and UDP to be proxied.

You need to be logged into the Community VPN to be able to access it. It is intended to be used for openvpn tests only.

There is a NTLM Proxy available at `10.18.0.99:8080`. You need to be logged into the Community VPN to be able to access it. It is intended to be used for openvpn tests only.

You can use both NTLMv1 and NTLMv2 style authentication against it.

Some explanation on [how we set up a NTLM proxy for testing](/Pages/NtlmProxyTestSetup).

If you're unfamiliar with git in general, take a look at these links:

* [git crash course](/Development/GitCrashCourse)

* [Git homepage](http://git-scm.com)

* http://progit.org/book/

* http://www.kernel.org/pub/software/scm/git/docs/gittutorial.html

* [git for SVN users](http://git.or.cz/course/svn.html)

In most cases, it's easiest to use [git-bisect](http://book.git-scm.com/5_finding_issues_-_git_bisect.html) to find the commit which introduced a problem. However, if the buildsystem is not in perfect working order all the way through from *last known good* commit to *known bad*, you may need to do manual bisecting such as was done Trac ticket 190. In practice, you can reset to an earlier commit with

Next build and test. If it still fails, move further back in history and retry, until you find a version that works. Optimally, you should bisecting at the middle of commits between *known good* and *known bad*, then repeat the procedure until you pinpoint the bad commit.

If you have hunch which commit might have introduced the bug, you can try reverting it to see what happens:

In case no later commits conflict with the commit, this will work. If there are conflicts, fix them manually or abort the revert and write a reverting commit manually.

It's often necessary to test individual patches sent to a mailing list. Patches that are real attachments are trivial to download and merge. However, sometimes the patches are stored inline, in the message body, which makes thing slightly more difficult. If you're running Mozilla Thunderbird, you export emails containing inline emails as mbox file using *ImportExportTools* add-on. These can then be applied to a git repository using *git am <mbox-filename>*.

Getting a "git am"-compatible patch out of a GitHub pull requests is simple:

You can then apply the patch:

Then you should amend the commit message to add information and to fix errors (if any):

* What pull request the patch was created from

* Who ACKed the patch

* Who relayed the patch (in case if you're not the author)

* Fix formatting issues

An example below:

After adjusting the commit message you can send the patch using git-send-email.

First, subscribe to openvpn-devel@lists.sourceforge.net:

[https://sourceforge.net/projects/openvpn/lists/openvpn-devel]

Now, configure git send-email in ~/.config/git/config.

(This file might be located at ~/.gitconfig instead.)

The required settings can be obtained from your email provider.

The email account has to be *the same one you used to subscribe to openvpn-devel*.

The above example is for the most common auth method, STARTTLS.

For SMTPS, do the below instead:

On Archlinux, git send-email requires two extra packages:

Now, it's ready. A single commit can be sent with:

Adjust the revision range as necessary if there are more than one patch.

Andj came up with a clever script in [http://thread.gmane.org/gmane.network.openvpn.devel/4869 an IRC meeting] to generate diffs that make reviewing refactoring patches easier:

This is similar to [http://research.microsoft.com/en-us/projects/symdiff Symdiff].