| lwIP
    2.1.2
    Lightweight IP stack | 
#include <udp.h>
| Data Fields | |
| ip_addr_t | local_ip | 
| u16_t | local_port | 
| ip4_addr_t | mcast_ip4 | 
| u8_t | mcast_ifindex | 
| u8_t | mcast_ttl | 
| u16_t | chksum_len_rx | 
| udp_recv_fn | recv | 
| void * | recv_arg | 
the UDP protocol control block
| u16_t udp_pcb::chksum_len_rx | 
used for UDP_LITE only
| ip_addr_t udp_pcb::local_ip | 
Common members of all PCB types
| u16_t udp_pcb::local_port | 
ports are in host byte order
| u8_t udp_pcb::mcast_ifindex | 
outgoing network interface for multicast packets, by interface index (if nonzero)
| ip4_addr_t udp_pcb::mcast_ip4 | 
outgoing network interface for multicast packets, by IPv4 address (if not 'any')
| u8_t udp_pcb::mcast_ttl | 
TTL for outgoing multicast packets
| udp_recv_fn udp_pcb::recv | 
receive callback function
| void* udp_pcb::recv_arg | 
user-supplied argument for the recv callback