[BUG] Wrong `lcp_state` flag handling prevents PPP from connecting to peer after peer disconnection/re-connection

[lzungri]

Description / Steps to reproduce the issue

If a PPP peer disconnects and then tries to reconnect it will send an 'LCP configure request' packet. The code that handles that scenario seems to be clearing the wrong lcp_state flag (LCP_RX_UP instead of LCP_TX_UP) and thus the nuttx ppp client will keep sending IPCP packets which are rightfully dropped by the new peer since it is still in the LCP negotiation phase.

Consider replacing this code:

ctx->lcp_state &= ~LCP_RX_UP;

with:

ctx->lcp_state &= ~LCP_TX_UP;

Source here:

nuttx-apps/netutils/pppd/lcp.c

Line 138 in 1f51bfe

ctx->lcp_state &= ~LCP_RX_UP;

I can create a PR if that helps.

On which OS does this issue occur?

[Linux]

What is the version of your OS?

Ubuntu

NuttX Version

12.6

Issue Architecture

[all]

Issue Area

[Networking]

Verification

• I have verified before submitting the report.

[xiaoxiang781216]

@lzungri could you provide a patch?

[lzungri]

PR here #2571

[cederom]

Thank you @lzungri :-) Patch just need minor comment formatting adjustment to pass CI, lets continue on PR thread :-)