Allow withholding the SYN|ACK packet by user code #863
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In certain use cases, it's desirable to not send a SYN|ACK packet immediately after receiving a SYN -- for example, a TCP proxy that doesn't want to do so until it's connected to the end destination, because the outgoing connection might get refused. (Currently, you have to send a SYN|ACK and then reset the connection afterwards in this case.) To fix this, add a simple `synack_paused` flag, controllable by user code, that withholds SYN|ACK packets in `SynReceived` state until it is unset.
Codecov ReportAttention:
Additional details and impacted files@@ Coverage Diff @@
## main #863 +/- ##
==========================================
- Coverage 79.55% 79.53% -0.02%
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Files 78 78
Lines 27917 27896 -21
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- Hits 22208 22186 -22
- Misses 5709 5710 +1 ☔ View full report in Codecov by Sentry. |
whitequark
reviewed
Dec 2, 2023
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In certain use cases, it's desirable to not send a SYN|ACK packet immediately after receiving a SYN -- for example, a TCP proxy that doesn't want to do so until it's connected to the end destination, because the outgoing connection might get refused. (Currently, you have to send a SYN|ACK and then reset the connection afterwards in this case, which is what we do in onionmasq.)
To fix this, add a simple
synack_pausedflag, controllable by user code, that withholds SYN|ACK packets inSynReceivedstate until it is unset.