Mediabot v3 continues the progressive modularization of the historical Partyline subsystem.

After MB678-I moved the TCP/DCC transport layer into:

Mediabot/Partyline/Transport.pm

MB678-II extracts the next coherent responsibility from Mediabot/Partyline.pm:

Mediabot/Partyline/SessionAuth.pm

This round focuses specifically on session lifecycle and authentication.

The Partyline command dispatcher and the command implementations intentionally remain in Mediabot/Partyline.pm.

The goal remains the same as in MB678-I: establish one clean architectural boundary at a time, preserve the historical Partyline API, and avoid mixing unrelated refactors into a single commit.

🏗️ What moved

The new SessionAuth.pm module now owns the session/authentication responsibilities around:

• authentication timeout cancellation;
• session shutdown and cleanup;
• reverse-DNS timeout handling;
• asynchronous reverse-DNS scheduling;
• display nickname resolution;
• Partyline broadcasts;
• Partyline chat broadcasts;
• Telnet echo negotiation;
• Telnet IAC stripping;
• per-IP brute-force checks;
• brute-force failure recording;
• brute-force state cleanup;
• login processing.

A total of 14 methods were extracted:

_cancel_auth_timeout
_close_session
_reverse_dns_timeout
_schedule_reverse_dns_lookup
_display_nick
_broadcast
_broadcast_chat
_telnet_echo_off
_telnet_echo_on
_strip_telnet_iac
_pl_bf_blocked
_pl_bf_record
_pl_bf_clear
_do_login

The historical Mediabot::Partyline method surface remains available through imports.

Existing callers therefore continue using the same API without needing to know that the implementation moved.

🧭 What deliberately did not move

One important decision in MB678-II was to leave:

_handle_line

inside Mediabot/Partyline.pm.

_handle_line sits directly on the boundary between the authentication state machine and the large Partyline command dispatcher.

Moving it together with Session/Auth would have blurred the new module boundary and mixed authentication work with the future command extraction.

So MB678-II keeps:

transport        → Partyline/Transport.pm
session + auth   → Partyline/SessionAuth.pm
dispatch         → Partyline.pm
commands         → Partyline.pm

This keeps the architecture explicit and leaves a clean starting point for the next Partyline round.

📐 Structural result

Before MB678-II:

Mediabot/Partyline.pm            : 6041 lines
Mediabot/Partyline/Transport.pm  : 1012 lines

After MB678-II:

Mediabot/Partyline.pm              : 5426 lines
Mediabot/Partyline/Transport.pm    : 1012 lines
Mediabot/Partyline/SessionAuth.pm  :  676 lines

The central Partyline module therefore loses another 615 lines of session/auth implementation.

A dedicated extraction contract was added:

t/cases/863_mb678_partyline_session_auth_extraction.t

The previous MB678 transport contract was also adjusted so that it continues validating the intended architecture after the second extraction.

🧪 Focused validation

MB678-II first went through targeted session/auth validation.

The exported-symbol contract was checked independently:

PASSED : 368/368

The focused Session/Auth suite then passed:

PASSED : 484/484  (3s)

This covered areas including:

• Partyline login behaviour;
• authentication timeout cleanup;
• asynchronous reverse DNS;
• per-IP brute-force protection;
• brute-force state-map bounds;
• configurable authentication policy;
• idempotent session closure;
• MB678-I transport compatibility;
• the new MB678-II extraction contract.

🧩 A focused-test isolation trap

During the first combined focused run, 85_exported_symbols_resolve.t reported a large cascade of failures.

The cause was not MB678-II.

One of the earlier focused tests deliberately installs a minimal fake JSON package containing only:

encode_json

and marks JSON.pm as loaded in %INC.

When 85_exported_symbols_resolve.t later attempted to load AdminCommands.pm, that module also needed:

decode_json

The isolated test process therefore saw an intentionally incomplete fake JSON module.

Running the export contract independently confirmed the real state:

PASSED : 368/368

The Session/Auth focused suite without that artificial ordering issue also passed completely:

PASSED : 484/484

No runtime code change was required.

🛡️ Security audit

The Partyline authentication-throttling invariant previously assumed that all authentication code lived physically inside Partyline.pm.

MB678-II updates the audit so that the security contract follows the new module boundary.

The invariant itself remains unchanged and fail-closed.

Final result:

Verdict: GO — all 11 security invariants hold.

The audit continues to verify:

• secret redaction;
• DCC token masking;
• TLS verification;
• safe external command execution;
• IRC output sanitisation;
• single-instance locking;
• HTTP download caps;
• authentication throttling on both IRC and Partyline paths.

🌐 Real Partyline runtime validation

The development instance was restarted with the new Session/Auth module.

The Partyline listener remained available:

0.0.0.0:23456 LISTEN

A real TCP session was then opened against the running bot.

The first prompt was received normally:

Mediabot Partyline

Please enter your nickname.

A real nickname was sent:

Te[u]K

and the session correctly advanced into the authentication state:

Enter your password.

No password was sent during the smoke test.

This validates the real runtime path through:

TCP transport
    ↓
session creation
    ↓
nickname parsing
    ↓
session/auth state
    ↓
password prompt

Result:

RC_SMOKE=0

Runtime logs remained clean:

OK: no obvious runtime error

⚡ Fast suite

The complete fast suite passed after the extraction:

PASSED : 5618/5618  (63s)

🧙 Full suite

Final full validation:

PASSED : 14530/14530  (207s)

No tests were removed, hidden or weakened to make the extraction pass.

🧹 Why this matters

Partyline started MB678 as a module of almost seven thousand lines containing several distinct responsibilities.

After the first two MB678 rounds, those responsibilities are already becoming explicit:

Mediabot/Partyline.pm
    dispatch + commands

Mediabot/Partyline/Transport.pm
    TCP / DCC transport

Mediabot/Partyline/SessionAuth.pm
    session lifecycle + authentication

This is more than moving code between files.

Each new boundary corresponds to a real runtime responsibility and has its own regression contract.

That makes Partyline easier to understand, safer to change and much easier to bisect if a future regression ever appears.

The password has not changed.

It simply has a much better guarded chamber now. 🔐

📦 Commit

Version : 3.4dev-20260820_154710
Commit  : a81729b

🔐 Give Partyline Sessions Their Own Chamber Without Changing the Password