- etcp_link_enter_init: new link on live conn sends NOINIT, not full reset
- etcp_link_enter_reinit: don't conn_reinit on single link recovery, preserve inflight
- handle_nl_link: fall through to remove_iface_sockets when if_indextoname fails
- duplicate INIT: add INFO log for diagnostic
Test: sequence checking (gaps=0 dups=0), exact socket/link counts, stale link
detection, conn health checks, full disconnect+reconnect phase
When ip link del removes an interface, the kernel sends RTM_DELLINK after the interface is unregistered from the name table.
if_indextoname fails and handle_nl_link silently returned without calling remove_iface_sockets,
causing old ETCP sockets to accumulate indefinitely.
Fix: fall through to remove_iface_sockets(ifindex) even when if_indextoname fails.
Test: added diagnostics (diag_dump_state, per-category debug levels to file) to verify socket/links cleanup.
evgeny