lwIP 2.2.0 Lightweight IP stack

Here is a list of all documented struct and union fields with links to the struct/union documentation for each field:

### - l -

- last_reporter_flag : igmp_group , mld_group
- lastconflict : acd
- lastdata : lwip_sock
- legacy_query : mdns_outmsg
- len : api_msg , netvector , pbuf
- linger : netconn
- link : stats_
- link_callback : netif
- link_speed : netif
- link_type : netif
- linkoutput : netif
- llipaddr : autoip
- local_ip : tcp_pcb , tcp_pcb_listen , udp_pcb
- local_port : udp_pcb
- lowpan6_context : lowpan6_ieee802154_data