James Tucker 2249be1ac8 derp/derpserver, cmd/derper: add optional TCP_SAVE_SYN MSS metrics ...

Add --tcp-save-syn on Linux to record client MSS in a Prometheus histogram. Count retrieval outcomes separately and limit saved-SYN error logs to one per ten minutes across clients. IPv6 extension headers are unsupported.

Estimate the network-namespace SYN rate from kernel counters once per second. Disable TCP_SAVE_SYN on listeners above 100,000/s or if rate measurement fails, leaving it off until restart.

Updates tailscale/corp#49139

Signed-off-by: James Tucker <james@tailscale.com>

2026-10-07 09:37:39 -07:00

..

testdata

derp/derpserver: split off derp.Server out of derp into its own package

2025-09-24 09:19:01 -07:00

debugclients_test.go

derp/derpserver: add app filter, connected-time sort, and JSON output to /debug/clients/

2026-09-29 09:18:15 -07:00

debugclients.go

derp/derpserver: add app filter, connected-time sort, and JSON output to /debug/clients/

2026-09-29 09:18:15 -07:00

derpserver_default.go

derp/derpserver, cmd/derper: add optional TCP_SAVE_SYN MSS metrics

2026-10-07 09:37:39 -07:00

derpserver_linux_test.go

derp/derpserver, cmd/derper: add optional TCP_SAVE_SYN MSS metrics

2026-10-07 09:37:39 -07:00

derpserver_linux.go

derp/derpserver, cmd/derper: add optional TCP_SAVE_SYN MSS metrics

2026-10-07 09:37:39 -07:00

derpserver_test.go

derp/derpserver: bound dup client sendHistory growth

2026-09-25 09:51:11 -07:00

derpserver.go

derp/derpserver, cmd/derper: add optional TCP_SAVE_SYN MSS metrics

2026-10-07 09:37:39 -07:00

fortest.go

derp, wgengine: let clients advertise an opaque app name to DERP servers

2026-07-20 07:33:44 -07:00

handler_test.go

derp/derpserver: serve hijacked connections on their own goroutine

2026-09-08 11:26:05 -07:00

handler.go

derp/derpserver: serve hijacked connections on their own goroutine

2026-09-08 11:26:05 -07:00

websocket.go

tstest/integration/jswasmtest: add headless-Chromium tests for @tailscale/connect

2026-05-20 10:48:29 -07:00