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#### Pre-Submission Checklist <!-- Go over all points below, and after creating the PR, tick all the checkboxes that apply --> <!-- All points should be verified, otherwise, read the CONTRIBUTING guidelines from above--> <!-- If you're unsure about any of these, don't hesitate to ask on sr-dev mailing list --> - [x] Commit message has the format required by CONTRIBUTING guide - [x] Commits are split per component (core, individual modules, libs, utils, ...) - [x] Each component has a single commit (if not, squash them into one commit) - [x] No commits to README files for modules (changes must be done to docbook files in `doc/` subfolder, the README file is autogenerated)

#### Type Of Change - [ ] Small bug fix (non-breaking change which fixes an issue) - [x] New feature (non-breaking change which adds new functionality) - [ ] Breaking change (fix or feature that would change existing functionality)

#### Checklist: <!-- Go over all points below, and after creating the PR, tick the checkboxes that apply --> - [ ] PR should be backported to stable branches - [x] Tested changes locally - [x] Related to issue #3823

#### Description <!-- Describe your changes in detail -->

This PR aims to implement what was discussed in [mailing list](https://lists.kamailio.org/mailman3/hyperkitty/list/sr-dev@lists.kamailio.or...) regarding some `tls.reload` and increasing memory usage.

It adds a new parameter `enable_shared_ctx` in `tls` module that if set to 0, preserves the old behavior and if set to 1 (other than 0 tbh), it creates a single SSL context that is being shared. This have the effect of using way less memory when initialized as well, but also minimizes (can't say it fixes the problem) the `tls.reload` memory increase.

I have also added a small markdown (comparison.md) file, where some comparisons where made between enabled/disabled shared context and with/without CA file (where the initial problem was occurring by the reporter).

Feedback would be necessary to verify whether this patch, acts as expected and kamailio works as intented.

You can view, comment on, or merge this pull request online at:

https://github.com/kamailio/kamailio/pull/3972

-- Commit Summary --

* tls: Add parameter for shared contexts * tls: Comparison for enable_shared_ctx

-- File Changes --

A comparison.md (15) M src/modules/tls/tls_domain.c (172) M src/modules/tls/tls_mod.c (11) M src/modules/tls/tls_mod.h (1)

-- Patch Links --

https://github.com/kamailio/kamailio/pull/3972.patch https://github.com/kamailio/kamailio/pull/3972.diff