Previously the agent called os.Exit(0) when receiving a server restart
event, requiring Docker or manual intervention to bring it back. Now
it reconnects immediately with a fresh session, which is better for
both dev (no lost process) and production (faster recovery).
Adds LLDP (Link Layer Discovery Protocol) topology discovery capability
to the agent for local network neighbor detection.
New Features:
- LLDP-MIB walker for discovering network neighbors via SNMP
- New LLDP_TOPOLOGY job type for topology discovery jobs
- Automatic IPv4 and IPv6 management address parsing
- Bulk neighbor discovery with full port information
Protocol Buffers:
- Added LldpTopologyResult message for topology data
- Added LldpNeighbor message for individual neighbor info
- Extended JobType enum with LLDP_TOPOLOGY (value 5)
Implementation:
- lldp.go: LLDP discovery logic with SNMP walking
- agent.go: Job dispatch and result channel handling
- Updated handleMessage signature to support LLDP results
- Result sent to Phoenix via "lldp_topology_result" event
LLDP-MIB OIDs:
- 1.0.8802.1.1.2.1.3.3.0 (lldpLocSysName)
- 1.0.8802.1.1.2.1.3.7.1.4 (lldpLocPortDesc)
- 1.0.8802.1.1.2.1.4.1.1.7 (lldpRemPortId)
- 1.0.8802.1.1.2.1.4.1.1.8 (lldpRemPortDesc)
- 1.0.8802.1.1.2.1.4.1.1.9 (lldpRemSysName)
- 1.0.8802.1.1.2.1.4.2.1.3 (lldpRemManAddr)
This enables the Phoenix web application to dispatch LLDP discovery
jobs to agents for local neighbor detection, reducing SNMP load on the
Phoenix server and improving discovery performance.
- Add missing checkResultCh parameter to all handleMessage() calls in tests
- Add missing checkResultCh parameter to all dispatchJob() calls in tests
- Add checks worker pool to testPools() function
- Fix IPv6 address formatting in executeTCPCheck using net.JoinHostPort
- Add strconv import for port conversion
Previously the agent proceeded to the main loop without confirming
the server accepted the channel join. A rejected join (e.g. invalid
token) left the agent running but silently non-functional. Now waits
for the join reply with a 10s timeout, returns error on rejection.
Reader goroutine starts before join send so the reply can be received.
Writer goroutine starts after join confirmation.
Previously, resetting slice length to 0 left previous protobuf data
(device IDs, OID values, credentials) in the backing array. Now zeros
the full capacity before returning to the pool.
handleMessage returns bool to signal session end instead of calling
osExit directly. Defers (pool stop, writeCh close, writerWg wait)
now run before exit, preventing in-flight result loss and panics
from writes to closed channels.
Fix 1: Limit inbound job payload size to 4MB to prevent OOM from malicious server
Fix 2: Worker pool submit accepts context and returns bool, prevents blocking event loop
Fix 3: Panic recovery in worker pool goroutines prevents permanent worker death
Fix 4: WebSocket handshake timeout (30s) prevents indefinite blocking on slow server
Fix 5: Writer goroutine propagates errors to main loop via writeErrCh
Replace unbounded goroutine spawning with fixed-size worker pools:
100 workers for SNMP, 20 for MikroTik, 50 for ping. Prevents file
descriptor exhaustion and device overload when handling thousands
of concurrent jobs. Pool provides backpressure when saturated.
