troll-patrol/src/simulation/user.rs

477 lines
18 KiB
Rust

// User behavior in simulation
use crate::{
get_date,
negative_report::NegativeReport,
positive_report::PositiveReport,
simulation::{
bridge::Bridge,
censor::{Censor, Hides::*, Speed::*, Totality::*},
state::State,
},
BridgeDistributor,
};
use lox_cli::{networking::*, *};
use lox_library::{
bridge_table::BridgeLine, cred::Lox, proto::check_blockage::MIN_TRUST_LEVEL, scalar_u32,
};
use rand::Rng;
use std::collections::HashMap;
use x25519_dalek::PublicKey;
// Helper function to probabilistically return true or false
pub fn event_happens(probability: f64) -> bool {
let mut rng = rand::thread_rng();
let num: f64 = rng.gen_range(0.0..1.0);
num < probability
}
pub struct User {
// Does this user cooperate with a censor?
censor: bool,
// 2-character country code
country: String,
// The user always has a primary credential. If this credential's bucket is
// blocked, the user may replace it or temporarily hold two credentials
// while waiting to migrate from the primary credential.
primary_cred: Lox,
secondary_cred: Option<Lox>,
// Does the user submit reports to Troll Patrol?
submits_reports: bool,
// How likely is this user to use bridges on a given day?
prob_use_bridges: f64,
}
impl User {
pub async fn new(state: &State) -> Self {
let cred = get_lox_credential(
&state.la_net,
&get_open_invitation(&state.la_net).await,
get_lox_pub(&state.la_pubkeys),
)
.await
.0;
// Probabilistically decide whether this user cooperates with a censor
let censor = event_happens(state.prob_user_is_censor);
// Probabilistically decide whether this user submits reports
let submits_reports = event_happens(state.prob_user_submits_reports);
// Probabilistically decide user's country
let mut rng = rand::thread_rng();
let mut num: f64 = rng.gen_range(0.0..1.0);
let cc = {
let mut cc = String::default();
for (country, prob) in &state.probs_user_in_country {
let prob = *prob;
if prob < num {
cc = country.to_string();
break;
} else {
num -= prob;
}
}
cc
};
// Randomly determine how likely this user is to use bridges on
// a given day
let prob_use_bridges = rng.gen_range(0.0..=1.0);
Self {
censor: censor,
country: cc,
primary_cred: cred,
secondary_cred: None,
submits_reports: submits_reports,
prob_use_bridges: prob_use_bridges,
}
}
// TODO: This should probably return an actual error type
pub async fn invite(&mut self, state: &State) -> Result<Self, String> {
let etable = get_reachability_credential(&state.la_net).await;
let (new_cred, invite) = issue_invite(
&state.la_net,
&self.primary_cred,
&etable,
get_lox_pub(&state.la_pubkeys),
get_reachability_pub(&state.la_pubkeys),
get_invitation_pub(&state.la_pubkeys),
)
.await;
self.primary_cred = new_cred;
let friend_cred = redeem_invite(
&state.la_net,
&invite,
get_lox_pub(&state.la_pubkeys),
get_invitation_pub(&state.la_pubkeys),
)
.await
.0;
// Probabilistically decide whether this user cooperates with a censor
// We do not influence this by the inviting friend's status. Anyone
// might have friends who are untrustworthy, and censors may invite
// non-censors to maintain an illusion of trustworthiness. Also, a
// "censor" user may not be knowingly helping a censor.
let censor = event_happens(state.prob_user_is_censor);
// Probabilistically decide whether this user submits reports
let submits_reports = event_happens(state.prob_user_submits_reports);
// Determine user's country
let cc = if event_happens(state.prob_friend_in_same_country) {
self.country.to_string()
} else {
// Probabilistically decide user's country
let mut rng = rand::thread_rng();
let mut num: f64 = rng.gen_range(0.0..1.0);
let mut cc = String::default();
for (country, prob) in &state.probs_user_in_country {
let prob = *prob;
if prob < num {
cc = country.to_string();
break;
} else {
num -= prob;
}
}
cc
};
// Randomly determine how likely this user is to use bridges on
// a given day
let mut rng = rand::thread_rng();
let prob_use_bridges = rng.gen_range(0.0..=1.0);
Ok(Self {
censor: censor,
country: cc,
primary_cred: friend_cred,
secondary_cred: None,
submits_reports: submits_reports,
prob_use_bridges: prob_use_bridges,
})
}
// Attempt to "connect" to the bridge, returns true if successful
pub fn connect(&self, state: &State, bridge: &mut Bridge, censor: &Censor) -> bool {
if censor.knows_bridge(&bridge.fingerprint) {
if censor.speed == Fast
|| censor.speed == Random && censor.delay_date <= get_date()
|| censor.speed == Lox && censor.has_lox_cred(&bridge.fingerprint)
{
if censor.totality == Full
|| censor.totality == Partial && event_happens(censor.partial_blocking_percent)
|| censor.totality == Throttling
{
// If censor tries to hide its censorship or
// throttles rather than actually blocking, record a
// false connection
if censor.hides == Hiding || censor.totality == Throttling {
bridge.connect_total(&self.country);
}
// Return false because the connection failed
return false;
}
}
}
// Connection may randomly fail, without censor intervention
if event_happens(state.prob_connection_fails) {
return false;
}
// If we haven't returned yet, the connection succeeded
bridge.connect_real(&self.country);
true
}
pub async fn send_negative_reports(state: &State, reports: Vec<NegativeReport>) {
let date = get_date();
let pubkey = serde_json::from_slice::<Option<PublicKey>>(
&state
.tp_net
.request(
"/nrkey".to_string(),
serde_json::to_string(&date).unwrap().into(),
)
.await,
)
.unwrap()
.unwrap();
for report in reports {
state
.tp_net
.request(
"/negativereport".to_string(),
bincode::serialize(&report.encrypt(&pubkey)).unwrap(),
)
.await;
}
}
pub async fn send_positive_reports(state: &State, reports: Vec<PositiveReport>) {
for report in reports {
state
.tp_net
.request("/positivereport".to_string(), report.to_json().into_bytes())
.await;
}
}
// User performs daily connection attempts, etc. and returns a
// vector of newly invited friends and a vector of fingerprints of
// successfully contacted bridges.
// TODO: The maps of bridges and censors should be Arc<Mutex<>> or
// something so we can parallelize this.
pub async fn daily_tasks(
&mut self,
state: &State,
bridges: &mut HashMap<[u8; 20], Bridge>,
censors: &mut HashMap<String, Censor>,
) -> (Vec<User>, Vec<[u8; 20]>) {
// Probabilistically decide if the user should use bridges today
if event_happens(self.prob_use_bridges) {
// Download bucket to see if bridge is still reachable. (We
// assume that this step can be done even if the user can't
// actually talk to the LA.)
let (bucket, reachcred) = get_bucket(&state.la_net, &self.primary_cred).await;
let level = scalar_u32(&self.primary_cred.trust_level).unwrap();
// Make sure each bridge in bucket is in the global bridges set
for bridgeline in bucket {
if !bridges.contains_key(&bridgeline.fingerprint) {
let bridge = Bridge::from_bridge_line(&bridgeline);
bridges.insert(bridgeline.fingerprint, bridge).unwrap();
}
// Also, if this user cooperates with censors, make sure
// each applicable censor knows about their bridges.
if self.censor {
if state.sharing {
for c in censors.values_mut() {
if !c.knows_bridge(&bridgeline.fingerprint) {
c.learn_bridge(&bridgeline.fingerprint);
}
}
} else {
let censor = censors.get_mut(&self.country).unwrap();
if !censor.knows_bridge(&bridgeline.fingerprint) {
censor.learn_bridge(&bridgeline.fingerprint);
}
}
}
}
// Can we level up the main credential?
let can_level_up = reachcred.is_some()
&& (level == 0
&& eligible_for_trust_promotion(&state.la_net, &self.primary_cred).await
|| level > 0 && eligible_for_level_up(&state.la_net, &self.primary_cred).await);
// Can we migrate the main credential?
let can_migrate = reachcred.is_none() && level >= MIN_TRUST_LEVEL;
// Can we level up the secondary credential?
let mut second_level_up = false;
let mut failed = Vec::<BridgeLine>::new();
let mut succeeded = Vec::<BridgeLine>::new();
for i in 0..bucket.len() {
// At level 0, we only have 1 bridge
if level > 0 || i == 0 {
if self.connect(
&state,
bridges.get_mut(&bucket[i].fingerprint).unwrap(),
&censors.get(&self.country).unwrap(),
) {
succeeded.push(bucket[i]);
} else {
failed.push(bucket[i]);
}
}
}
let second_cred = if succeeded.len() < 1 {
if self.secondary_cred.is_some() {
std::mem::replace(&mut self.secondary_cred, None)
} else {
// Get new credential
let cred = get_lox_credential(
&state.la_net,
&get_open_invitation(&state.la_net).await,
get_lox_pub(&state.la_pubkeys),
)
.await
.0;
Some(cred)
}
} else {
// If we're able to connect with the primary credential, don't
// keep a secondary one.
None
};
if second_cred.is_some() {
let second_cred = second_cred.as_ref().unwrap();
let (second_bucket, second_reachcred) =
get_bucket(&state.la_net, &second_cred).await;
if !bridges.contains_key(&second_bucket[0].fingerprint) {
bridges
.insert(
second_bucket[0].fingerprint,
Bridge::from_bridge_line(&second_bucket[0]),
)
.unwrap();
}
if self.connect(
&state,
bridges.get_mut(&second_bucket[0].fingerprint).unwrap(),
&censors.get(&self.country).unwrap(),
) {
succeeded.push(second_bucket[0]);
if second_reachcred.is_some()
&& eligible_for_trust_promotion(&state.la_net, &second_cred).await
{
second_level_up = true;
}
} else {
failed.push(second_bucket[0]);
}
}
let mut negative_reports = Vec::<NegativeReport>::new();
let mut positive_reports = Vec::<PositiveReport>::new();
if self.submits_reports {
for bridge in &failed {
negative_reports.push(NegativeReport::from_bridgeline(
*bridge,
self.country.to_string(),
BridgeDistributor::Lox,
));
}
if level >= 3 {
for bridge in &succeeded {
positive_reports.push(
PositiveReport::from_lox_credential(
bridge.fingerprint,
None,
&self.primary_cred,
get_lox_pub(&state.la_pubkeys),
self.country.to_string(),
)
.unwrap(),
);
}
}
}
// We might restrict these steps to succeeded.len() > 0, but
// we do assume the user can contact the LA somehow, so
// let's just allow it.
if can_level_up {
let cred = level_up(
&state.la_net,
&self.primary_cred,
&reachcred.unwrap(),
get_lox_pub(&state.la_pubkeys),
get_reachability_pub(&state.la_pubkeys),
)
.await;
self.primary_cred = cred;
self.secondary_cred = None;
if self.censor {
// Make sure censor has access to each bridge and
// each credential
let censor = censors.get_mut(&self.country).unwrap();
let (bucket, reachcred) = get_bucket(&state.la_net, &self.primary_cred).await;
for bl in bucket {
censor.learn_bridge(&bl.fingerprint);
censor.give_lox_cred(&bl.fingerprint, &self.primary_cred);
}
}
}
// We favor starting over at level 1 to migrating
else if second_level_up {
let second_cred = second_cred.as_ref().unwrap();
let cred = trust_migration(
&state.la_net,
&second_cred,
&trust_promotion(&state.la_net, &second_cred, get_lox_pub(&state.la_pubkeys))
.await,
get_lox_pub(&state.la_pubkeys),
get_migration_pub(&state.la_pubkeys),
)
.await;
self.primary_cred = cred;
self.secondary_cred = None;
} else if can_migrate {
let cred = blockage_migration(
&state.la_net,
&self.primary_cred,
&check_blockage(
&state.la_net,
&self.primary_cred,
get_lox_pub(&state.la_pubkeys),
)
.await,
get_lox_pub(&state.la_pubkeys),
get_migration_pub(&state.la_pubkeys),
)
.await;
self.primary_cred = cred;
self.secondary_cred = None;
} else if second_cred.is_some() {
// Couldn't connect with primary credential
if succeeded.len() > 0 {
// Keep the second credential only if it's useful
self.secondary_cred = second_cred;
}
}
if negative_reports.len() > 0 {
Self::send_negative_reports(&state, negative_reports).await;
}
if positive_reports.len() > 0 {
Self::send_positive_reports(&state, positive_reports).await;
}
// Invite friends if applicable
let invitations = scalar_u32(&self.primary_cred.invites_remaining).unwrap();
let mut new_friends = Vec::<User>::new();
for _i in 0..invitations {
if event_happens(state.prob_user_invites_friend) {
match self.invite(&state).await {
Ok(friend) => {
// You really shouldn't push your friends,
// especially new ones whose boundaries you
// might not know well.
new_friends.push(friend);
}
Err(e) => {
println!("{}", e);
}
}
}
}
// List of fingerprints we contacted. This should not
// actually be more than one.
let mut connections = Vec::<[u8; 20]>::new();
for bridge in succeeded {
connections.push(bridge.get_hashed_fingerprint());
}
(new_friends, connections)
} else {
(Vec::<User>::new(), Vec::<[u8; 20]>::new())
}
}
}