Type nwio_ipconf_t contains the ip address information of an ip port (i.e., an element in ip_port_table[]:
typedef struct nwio_ipconf
{
u32_t nwic_flags;
ipaddr_t nwic_ipaddr;
ipaddr_t nwic_netmask;
} nwio_ipconf_t;
nwic_flags: reflects whether the ip address and the subnet mask have been set. The different flags are as follows:
#define NWIC_NOFLAGS 0x0
#define NWIC_FLAGS 0x3
#define NWIC_IPADDR_SET 0x1
#define NWIC_NETMASK_SET 0x2
nwic_ipaddr: the ip address (e.g., 192.168.5.5)
nwic_netmask: the subnet mask (e.g., 255.255.255.0)