Add support for binding multiple UDP sockets

Add support for binding multiple UDP sockets for with SO_REUSEPORT flag in order to overcome performance hit caused by sharing one socket and waiting on one single lock in kernel.

Reassigned to @jvcelak

Added 1 commit:

• 6ba4901d - reuseport: fix memory leak

Added 83 commits:

• 6ba4901d...b45701be - 79 commits from branch master
• b87cd406 - Add support for binding multiple UDP sockets
• 6cfcae77 - reuseport: fix memory leak
• 44b7a852 - reuseport: make sure we don't exceed UDP fd set
• d4819924 - fix persistent fuzzing with SO_REUSEPORT

Added 7 commits:

• bec0b58b - server: cleanup, use enum instead of define
• bd81113c - UDP: fix min and max descriptor tracking
• 2244e7a9 - reuseport: fix coding style, ifdef on variables not code
• 53a2ca5e - server: add server_deinit_iface to clear iface structure without free
• 4861c5b1 - reuseport: less copy-paste, ifdef on variables not code
• 53e66940 - reuseport: more generic name for multiple address binding
• 0aa405b2 - reuseport: cleanup configure

I've rebased the changes on current master. And did some code cleanup.

Unresolved issues:

• Test server threads reconfiguration.
• Verify SO_REUSEPORT detection on FreeBSD. The have REUSEPORT with different semantics.

Broken on FreeBSD 10.1.

checking for socket REUSEPORT... yes

Added 12 commits:

• 6645878c - 1 commit from branch master
• 9fcc226c - Add support for binding multiple UDP sockets
• ed1fc401 - reuseport: fix memory leak
• 13b14561 - reuseport: make sure we don't exceed UDP fd set
• 858b0f73 - fix persistent fuzzing with SO_REUSEPORT
• 7f4a9562 - server: cleanup, use enum instead of define
• 91a35ee0 - UDP: fix min and max descriptor tracking
• e4a0f441 - reuseport: fix coding style, ifdef on variables not code
• d2b86042 - server: add server_deinit_iface to clear iface structure without free
• e798269d - reuseport: less copy-paste, ifdef on variables not code
• d507167b - reuseport: more generic name for multiple address binding
• 05ae94cb - reuseport: cleanup configure

Added 1 commit:

• 08f81352 - reuseport: fix null pointer dereference

Added 1 commit:

• 4ee548ad - Disable binding multiple sockets on non-Linux

Yes, you are right... Fixed, hopefully, in 4ee548ad .

Added 1 commit:

• c5eda24d - configure: fail if SO_REUSEPORT is requested but not supported

Threads reconfiguration is broken even in master. I'll fix this separately.

Reassigned to @dsalzman

@dsalzman, please can you review my changes?

This check should be bellow the systemd checks (next to the following reuseport checks)!

I've moved the check from server to common dependencies. The support has to be detected for libknot/internal.

Added 1 commit:

• 124bcd41 - reuseport: detect as a common dependency

Added 1 commit:

• ac2d80b0 - reuseport: detect as a common dependency

mentioned in commit 550930c3

Status changed to merged