<!-- Kamailio Pull Request Template -->

<!-- IMPORTANT: - for detailed contributing guidelines, read: https://github.com/kamailio/kamailio/blob/master/.github/CONTRIBUTING.md - pull requests must be done to master branch, unless they are backports of fixes from master branch to a stable branch - backports to stable branches must be done with 'git cherry-pick -x ...' - code is contributed under BSD for core and main components (tm, sl, auth, tls) - code is contributed GPLv2 or a compatible license for the other components - GPL code is contributed with OpenSSL licensing exception -->

#### 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 - [ ] Related to issue #XXXX (replace XXXX with an open issue number)

#### Description <!-- Describe your changes in detail --> We have seen that in deployments where there are strict port requirements on both side, there are tcp connections in TIME_WAIT state causing no fresh TCP connections possible until the TIME_WAIT is gone. In a lot of these case the clients are sending from them self a RST after they send a FIN,ACK from there side but some aren't doing this. The basic idea of this PR is to give an extra option for the tcp configuration from the cfg to trigger always an RST on connection close from Kamailio side. This currently done by enabling SO_LINGER with a value of 0 just before close. You can view, comment on, or merge this pull request online at:

https://github.com/kamailio/kamailio/pull/3101

-- Commit Summary --

* core: add an option to trigger also an RST on tcp connection close

-- File Changes --

M src/core/cfg.lex (2) M src/core/cfg.y (9) M src/core/tcp_main.c (7) M src/core/tcp_options.c (3) M src/core/tcp_options.h (1)

-- Patch Links --

https://github.com/kamailio/kamailio/pull/3101.patch https://github.com/kamailio/kamailio/pull/3101.diff