const NETINFO_ADDR_TYPE_IPV4 = 4;
const NETINFO_ADDR_TYPE_IPV6 = 6;

struct netinfo_addr {
  u8 addr_type IN [NETINFO_ADDR_TYPE_IPV4, NETINFO_ADDR_TYPE_IPV6];
  u8 len IN [4, 16];
  union addr[addr_type] {
    NETINFO_ADDR_TYPE_IPV4: u32 ipv4;
    NETINFO_ADDR_TYPE_IPV6: u8 ipv6[16];
    default: fail;
  };
  
}

struct netinfo_cell {
  u32 timestamp;
  struct netinfo_addr other_addr;
  u8 n_my_addrs;
  struct netinfo_addr my_addrs[n_my_addrs];
}