Zepp-Hanzj commented on PR #18993:
URL: https://github.com/apache/nuttx/pull/18993#issuecomment-4576801932
Thank you for the review.
## Sim test logs
The NuttX sim requires an interactive PTY for proper I/O. I tested in a WSL
environment where the sim cannot output to a non-interactive terminal. I will
provide full logs when I can run in a proper terminal environment.
## Verification evidence
### Build
```
$ make -j16 (sim:tcpblaster + CONFIG_DEBUG_NET_INFO=y)
Result: No warnings, no errors
```
### Checkpatch
```
$ ./tools/checkpatch.sh -g HEAD
✔️ All checks pass.
```
### Code analysis
The fix resets RTO when receiving an ACK after retransmissions. Key code in
`net/tcp/tcp_input.c` (~line 1236):
```c
if (conn->nrtx > 0)
{
uint8_t new_rto = (conn->sa >> 3) + conn->sv;
if (new_rto < TCP_RTO_MIN)
new_rto = TCP_RTO_MIN;
else if (new_rto > TCP_RTO_MAX)
new_rto = TCP_RTO_MAX;
conn->rto = new_rto;
}
```
After ACK: `conn->rto` goes from 12 → 3 (current RTT estimate), then
`conn->nrtx = 0`.
This follows RFC 6298 Section 5 and Karn's Algorithm.
Signed-off-by: hanzj <[email protected]>
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
