Function do_lldp

network_diagnostics.py:243–273

Return discovered switch neighbors via lldpctl. lldpd (configured with -c -e -f -s) also decodes CDPv1/v2 (Cisco), EDP (Extreme), FDP (Foundry) and SONMP (Nortel) in addition to LLDP. VLAN id/name are included when the neighbor advertises them.

()

            resolved_from, ip = ip, resolved
        except (OSError, socket.gaierror):
            return {'success': False, 'error': f'Not a valid IP or resolvable host: {target}'}
    try:
        rec = ip_intel.lookup(ip, allow_network=not offline)
    except Exception as exc:
        return {'success': False, 'error': f'lookup failed: {exc}'}
    rec['success'] = True
    rec['report'] = ip_intel.report(rec)
    if resolved_from:
        rec['resolved_from'] = resolved_from
    return rec


def _probe_egress(iface, timeout=4.0):
    """Can `iface` actually reach the internet? True / False / None (unknown).

    Binds the probe socket to the *device* (SO_BINDTODEVICE) and TCP-connects to
    a public endpoint, so the answer reflects that NIC and nothing else. This is
    the only trustworthy signal we have:
      - a default route only says a gateway is configured, not that it works;
      - source-address binding proves nothing at all — a probe bound to docker0's
        address reaches the internet fine, because the packet just leaves via the
        default-route interface wearing that address.
    Returns None when the bind is not permitted (needs CAP_NET_RAW), so callers
    can proceed rather than block on a check they could not run."""
    unknown = False
    for dst in (('1.1.1.1', 443), ('8.8.8.8', 443)):
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        try:
            s.settimeout(timeout)
            s.setsockopt(socket.SOL_SOCKET, socket.SO_BINDTODEVICE, iface.encode() + b'\0')
            s.connect(dst)
            return True
        except PermissionError:
            unknown = True