server: Improve handling of sockets which go away #130
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After e.g.
```
recvfrom(22, 0x7f7dc8033830, 1500, 0, NULL, NULL) = -1 ECONNRESET (Connection reset by peer)
```
the socket is no longer valid for read or write, but we only shutdown the
connection on a return of 0, meaning we subsequently hit:
```
sendto(22, "..."..., 265, MSG_NOSIGNAL, NULL, 0) = -1 EPIPE (Broken pipe)
```
which exits the inside I/O loop with:
```
Error: Inside IO loop exited
Caused by:
0: Inside data handling error
1: WolfSSL Error: Fatal: code: -308, what: error state on socket
2: Fatal: code: -308, what: error state on socket
```
... this could be (and most probably is) a connection specific issue and need not result in the whole process exiting. If the error is fatal for the connection then tear it down.
... when sending the goodbye message a failure could happen if the socket (for a TCP connection) has already been closed by the peer (which is one reason we might be disconnecting). Similarly for the `try_shutdown` call which may try to send a TLS close notification. All callers already ignore the result of `Connection::disconnect`, so in practice this is a noop change, but it more closely matches the "just a courtesy" intention.
7 tasks
xv-raihaan-m
approved these changes
Nov 22, 2024
kp-mariappan-ramasamy
approved these changes
Nov 22, 2024
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Description
I have observed evidence of a rare case where the server process exited due to an issue with a specific TCP connection. First:
followed by:
which causes the inside I/O loop to exit:
I think this scenario can arise if there is traffic inflight inside->outside at just the moment the socket is going away.
I've not been able to reproduce at will. The first two commits are based on code inspection.
The third commit is more of a cleanup given that all callers ignore the result of
Connection::disconnectalready.Motivation and Context
Issues with a single connection should not cause the whole server process to exit.
How Has This Been Tested?
E2E
Types of changes
Checklist:
main