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- use crate::{BridgeInfo, BridgeInfoType};
- use lox_library::proto::{level_up::LEVEL_INTERVAL, trust_promotion::UNTRUSTED_INTERVAL};
- use nalgebra::DVector;
- use statrs::distribution::{Continuous, MultivariateNormal};
- use std::{
- cmp::min,
- collections::{BTreeMap, HashSet},
- };
- /// Provides a function for predicting which countries block this bridge
- pub trait Analyzer {
- /// Evaluate open-entry bridge. Returns true if blocked, false otherwise.
- fn stage_one(
- &self,
- confidence: f64,
- bridge_ips: &[u32],
- bridge_ips_today: u32,
- negative_reports: &[u32],
- negative_reports_today: u32,
- ) -> bool;
- /// Evaluate invite-only bridge without positive reports. Return true if
- /// blocked, false otherwise.
- fn stage_two(
- &self,
- confidence: f64,
- bridge_ips: &[u32],
- bridge_ips_today: u32,
- negative_reports: &[u32],
- negative_reports_today: u32,
- ) -> bool;
- /// Evaluate invite-only bridge with positive reports. Return true if
- /// blocked, false otherwise.
- fn stage_three(
- &self,
- confidence: f64,
- bridge_ips: &[u32],
- bridge_ips_today: u32,
- negative_reports: &[u32],
- negative_reports_today: u32,
- positive_reports: &[u32],
- positive_reports_today: u32,
- ) -> bool;
- }
- /// Accepts an analyzer, information about a bridge, and a confidence value.
- /// Returns a set of country codes where the bridge is believed to be blocked.
- pub fn blocked_in(
- analyzer: &dyn Analyzer,
- bridge_info: &BridgeInfo,
- confidence: f64,
- date: u32,
- ) -> HashSet<String> {
- // TODO: Re-evaluate past days if we have backdated reports
- let mut blocked_in = HashSet::<String>::new();
- let today = date;
- let age = today - bridge_info.first_seen;
- for (country, info) in &bridge_info.info_by_country {
- if info.blocked {
- // Assume bridges never become unblocked
- blocked_in.insert(country.to_string());
- } else {
- // Get today's values
- let new_map_binding = BTreeMap::<BridgeInfoType, u32>::new();
- // TODO: Evaluate on yesterday if we don't have data for today?
- let today_info = match info.info_by_day.get(&today) {
- Some(v) => v,
- None => &new_map_binding,
- };
- let bridge_ips_today = match today_info.get(&BridgeInfoType::BridgeIps) {
- Some(v) => *v,
- None => 0,
- };
- let negative_reports_today = match today_info.get(&BridgeInfoType::NegativeReports) {
- Some(v) => *v,
- None => 0,
- };
- let positive_reports_today = match today_info.get(&BridgeInfoType::PositiveReports) {
- Some(v) => *v,
- None => 0,
- };
- let num_days = min(age, UNTRUSTED_INTERVAL);
- // Get time series for last num_days
- let mut bridge_ips = vec![0; num_days as usize];
- let mut negative_reports = vec![0; num_days as usize];
- let mut positive_reports = vec![0; num_days as usize];
- for i in 0..num_days {
- let date = today - num_days + i - 1;
- let new_map_binding = BTreeMap::<BridgeInfoType, u32>::new();
- let day_info = match info.info_by_day.get(&date) {
- Some(v) => v,
- None => &new_map_binding,
- };
- bridge_ips[i as usize] = match day_info.get(&BridgeInfoType::BridgeIps) {
- Some(&v) => v,
- None => 0,
- };
- negative_reports[i as usize] = match day_info.get(&BridgeInfoType::NegativeReports)
- {
- Some(&v) => v,
- None => 0,
- };
- positive_reports[i as usize] = match day_info.get(&BridgeInfoType::PositiveReports)
- {
- Some(&v) => v,
- None => 0,
- };
- }
- // Evaluate using appropriate stage based on age of the bridge
- if age < UNTRUSTED_INTERVAL {
- // open-entry bridge
- if analyzer.stage_one(
- confidence,
- &bridge_ips,
- bridge_ips_today,
- &negative_reports,
- negative_reports_today,
- ) {
- blocked_in.insert(country.to_string());
- }
- } else if age
- < UNTRUSTED_INTERVAL + LEVEL_INTERVAL[1] + LEVEL_INTERVAL[2] + UNTRUSTED_INTERVAL
- {
- // invite-only bridge without 30+ days of historical data on
- // positive reports
- if analyzer.stage_two(
- confidence,
- &bridge_ips,
- bridge_ips_today,
- &negative_reports,
- negative_reports_today,
- ) {
- blocked_in.insert(country.to_string());
- }
- } else {
- // invite-only bridge that has been up long enough that it
- // might have 30+ days of historical data on positive reports
- if analyzer.stage_three(
- confidence,
- &bridge_ips,
- bridge_ips_today,
- &negative_reports,
- negative_reports_today,
- &positive_reports,
- positive_reports_today,
- ) {
- blocked_in.insert(country.to_string());
- }
- }
- }
- }
- blocked_in
- }
- // Analyzer implementations
- /// Dummy example that never thinks bridges are blocked
- pub struct ExampleAnalyzer {}
- impl Analyzer for ExampleAnalyzer {
- fn stage_one(
- &self,
- _confidence: f64,
- _bridge_ips: &[u32],
- _bridge_ips_today: u32,
- _negative_reports: &[u32],
- _negative_reports_today: u32,
- ) -> bool {
- false
- }
- fn stage_two(
- &self,
- _confidence: f64,
- _bridge_ips: &[u32],
- _bridge_ips_today: u32,
- _negative_reports: &[u32],
- _negative_reports_today: u32,
- ) -> bool {
- false
- }
- fn stage_three(
- &self,
- _confidence: f64,
- _bridge_ips: &[u32],
- _bridge_ips_today: u32,
- _negative_reports: &[u32],
- _negative_reports_today: u32,
- _positive_reports: &[u32],
- _positive_reports_today: u32,
- ) -> bool {
- false
- }
- }
- /// Model data as multivariate normal distribution
- pub struct NormalAnalyzer {
- max_threshold: u32,
- scaling_factor: f64,
- }
- impl NormalAnalyzer {
- pub fn new(max_threshold: u32, scaling_factor: f64) -> Self {
- Self {
- max_threshold,
- scaling_factor,
- }
- }
- fn mean_vector_and_covariance_matrix(data: &[&[u32]]) -> (Vec<f64>, Vec<f64>) {
- let n = data.len();
- // Compute mean vector
- let mean_vec = {
- let mut mean_vec = Vec::<f64>::new();
- for var in data {
- mean_vec.push({
- let mut sum = 0.0;
- for count in *var {
- sum += *count as f64;
- }
- sum / var.len() as f64
- });
- }
- mean_vec
- };
- // Compute covariance matrix
- let cov_mat = {
- let mut cov_mat = Vec::<f64>::new();
- // We don't need to recompute Syx, but we currently do
- for i in 0..n {
- for j in 0..n {
- cov_mat.push({
- let var1 = data[i];
- let var1_mean = mean_vec[i];
- let var2 = data[j];
- let var2_mean = mean_vec[j];
- assert_eq!(var1.len(), var2.len());
- let mut sum = 0.0;
- for index in 0..var1.len() {
- sum +=
- (var1[index] as f64 - var1_mean) * (var2[index] as f64 - var2_mean);
- }
- sum / var1.len() as f64
- });
- }
- }
- cov_mat
- };
- (mean_vec, cov_mat)
- }
- }
- impl Analyzer for NormalAnalyzer {
- /// Evaluate open-entry bridge based on only today's data
- fn stage_one(
- &self,
- _confidence: f64,
- _bridge_ips: &[u32],
- bridge_ips_today: u32,
- _negative_reports: &[u32],
- negative_reports_today: u32,
- ) -> bool {
- negative_reports_today > self.max_threshold
- || f64::from(negative_reports_today) > self.scaling_factor * f64::from(bridge_ips_today)
- }
- /// Evaluate invite-only bridge based on last 30 days
- fn stage_two(
- &self,
- confidence: f64,
- bridge_ips: &[u32],
- bridge_ips_today: u32,
- negative_reports: &[u32],
- negative_reports_today: u32,
- ) -> bool {
- assert!(bridge_ips.len() >= UNTRUSTED_INTERVAL as usize);
- assert_eq!(bridge_ips.len(), negative_reports.len());
- let (mean_vec, cov_mat) =
- Self::mean_vector_and_covariance_matrix(&[bridge_ips, negative_reports]);
- let bridge_ips_mean = mean_vec[0];
- let negative_reports_mean = mean_vec[1];
- let mvn = MultivariateNormal::new(mean_vec, cov_mat).unwrap();
- if mvn.pdf(&DVector::from_vec(vec![
- bridge_ips_today as f64,
- negative_reports_today as f64,
- ])) < confidence
- {
- (negative_reports_today as f64) > negative_reports_mean
- || (bridge_ips_today as f64) < bridge_ips_mean
- } else {
- false
- }
- }
- /// Evaluate invite-only bridge with lv3+ users submitting positive reports
- fn stage_three(
- &self,
- confidence: f64,
- bridge_ips: &[u32],
- bridge_ips_today: u32,
- negative_reports: &[u32],
- negative_reports_today: u32,
- positive_reports: &[u32],
- positive_reports_today: u32,
- ) -> bool {
- assert!(bridge_ips.len() >= UNTRUSTED_INTERVAL as usize);
- assert_eq!(bridge_ips.len(), negative_reports.len());
- assert_eq!(bridge_ips.len(), positive_reports.len());
- let (mean_vec, cov_mat) = Self::mean_vector_and_covariance_matrix(&[
- bridge_ips,
- negative_reports,
- positive_reports,
- ]);
- let bridge_ips_mean = mean_vec[0];
- let negative_reports_mean = mean_vec[1];
- let positive_reports_mean = mean_vec[2];
- let mvn = MultivariateNormal::new(mean_vec, cov_mat).unwrap();
- if mvn.pdf(&DVector::from_vec(vec![
- bridge_ips_today as f64,
- negative_reports_today as f64,
- positive_reports_today as f64,
- ])) < confidence
- {
- (negative_reports_today as f64) > negative_reports_mean
- || (bridge_ips_today as f64) < bridge_ips_mean
- || (positive_reports_today as f64) < positive_reports_mean
- } else {
- false
- }
- }
- }
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