lox_cli/src/client_lib.rs

use async_trait::async_trait;
use curve25519_dalek::scalar::Scalar;
use lox::bridge_table::BridgeLine;
use lox::bridge_table::ENC_BUCKET_BYTES;
use lox::proto::*;
use lox::IssuerPubKey;
use lox::OPENINV_LENGTH;
use serde::{Deserialize, Serialize};
use serde_with::serde_as;
use std::time::Duration;

// used for testing function
use std::io::Write;

// provides a generic way to make network requests
#[async_trait]
pub trait Networking {
    async fn request(&self, endpoint: String, body: Vec<u8>) -> Vec<u8>;
}

// From https://gitlab.torproject.org/onyinyang/lox-server/-/blob/main/src/main.rs
// TODO: Move this to main Lox library?
#[serde_as]
#[derive(Serialize, Deserialize)]
pub struct Invite {
    #[serde_as(as = "[_; OPENINV_LENGTH]")]
    invite: [u8; OPENINV_LENGTH],
}
#[serde_as]
#[derive(Serialize, Deserialize)]
pub struct EncBridgeTable {
    #[serde_as(as = "Vec<[_; ENC_BUCKET_BYTES]>")]
    etable: Vec<[u8; ENC_BUCKET_BYTES]>,
}

// These two functions should only be used for testing.
// This file should probably belong to the client, not the library.
const TIME_OFFSET_FILENAME: &str = "time_offset.json";
fn get_time_offset() -> u32 {
    if std::path::Path::new(&TIME_OFFSET_FILENAME).exists() {
        let infile = std::fs::File::open(&TIME_OFFSET_FILENAME).unwrap();
        serde_json::from_reader(infile).unwrap()
    } else {
        0
    }
}
fn save_time_offset(secs: &u32) {
    let mut outfile =
        std::fs::File::create(&TIME_OFFSET_FILENAME).expect("Failed to create time_offset");
    write!(outfile, "{}", serde_json::to_string(&secs).unwrap())
        .expect("Failed to write to time_offset");
}

/// Get today's (real or simulated) date
///
/// This function is modified from the lox lib.rs
fn today(time_offset: Duration) -> u32 {
    // We will not encounter negative Julian dates (~6700 years ago)
    // or ones larger than 32 bits
    (time::OffsetDateTime::now_utc().date() + time_offset)
        .julian_day()
        .try_into()
        .unwrap()
}

// Helper functions to get public keys from vector
pub fn get_lox_pub(lox_auth_pubkeys: &Vec<IssuerPubKey>) -> &IssuerPubKey {
    &lox_auth_pubkeys[0]
}

pub fn get_migration_pub(lox_auth_pubkeys: &Vec<IssuerPubKey>) -> &IssuerPubKey {
    &lox_auth_pubkeys[1]
}

pub fn get_migrationkey_pub(lox_auth_pubkeys: &Vec<IssuerPubKey>) -> &IssuerPubKey {
    &lox_auth_pubkeys[2]
}

pub fn get_reachability_pub(lox_auth_pubkeys: &Vec<IssuerPubKey>) -> &IssuerPubKey {
    &lox_auth_pubkeys[3]
}

pub fn get_invitation_pub(lox_auth_pubkeys: &Vec<IssuerPubKey>) -> &IssuerPubKey {
    &lox_auth_pubkeys[4]
}

// Helper function to get credential trust level as i8
// (Note that this value should only be 0-4)
pub fn get_cred_trust_level(cred: &lox::cred::Lox) -> i8 {
    let trust_levels: [Scalar; 5] = [
        Scalar::zero(),
        Scalar::one(),
        Scalar::from(2u64),
        Scalar::from(3u64),
        Scalar::from(4u8),
    ];
    for i in 0..trust_levels.len() {
        if cred.trust_level == trust_levels[i] {
            return i.try_into().unwrap();
        }
    }
    -1
}

// Download Lox Auth pubkeys
pub async fn get_lox_auth_keys(net: &dyn Networking) -> Vec<IssuerPubKey> {
    let resp = net.request("/pubkeys".to_string(), [].to_vec()).await;
    let lox_auth_pubkeys: Vec<IssuerPubKey> = serde_json::from_slice(&resp).unwrap();
    lox_auth_pubkeys
}

// Get encrypted bridge table
pub async fn get_reachability_credential(net: &dyn Networking) -> Vec<[u8; ENC_BUCKET_BYTES]> {
    let resp = net.request("/reachability".to_string(), [].to_vec()).await;
    let reachability_cred: EncBridgeTable = serde_json::from_slice(&resp).unwrap();
    reachability_cred.etable
}

// Get an open invitation
pub async fn get_open_invitation(net: &dyn Networking) -> [u8; OPENINV_LENGTH] {
    let resp = net.request("/invite".to_string(), [].to_vec()).await;
    let open_invite: [u8; OPENINV_LENGTH] = serde_json::from_slice::<Invite>(&resp).unwrap().invite;
    open_invite
}

// Get a Lox Credential from an open invitation
pub async fn get_lox_credential(
    net: &dyn Networking,
    open_invite: &[u8; OPENINV_LENGTH],
    lox_pub: &IssuerPubKey,
) -> (lox::cred::Lox, BridgeLine) {
    let (req, state) = open_invite::request(&open_invite);
    let encoded_req: Vec<u8> = serde_json::to_vec(&req).unwrap();
    let encoded_resp = net.request("/openreq".to_string(), encoded_req).await;
    let decoded_resp: open_invite::Response = serde_json::from_slice(&encoded_resp).unwrap();
    let (cred, bridgeline) = open_invite::handle_response(state, decoded_resp, &lox_pub).unwrap();
    (cred, bridgeline)
}

// Get a migration credential to migrate to higher trust
pub async fn trust_promotion(
    net: &dyn Networking,
    lox_cred: &lox::cred::Lox,
    lox_pub: &IssuerPubKey,
) -> lox::cred::Migration {
    // FOR TESTING ONLY
    let time_offset = get_time_offset() + 60 * 60 * 24 * 31;
    save_time_offset(&time_offset);

    let (req, state) =
//        trust_promotion::request(&lox_cred, &lox_pub, today(Duration::ZERO)).unwrap();
        trust_promotion::request(&lox_cred, &lox_pub, today(Duration::from_secs(time_offset.into()))).unwrap(); // FOR TESTING ONLY
    let encoded_req: Vec<u8> = serde_json::to_vec(&req).unwrap();
    let encoded_resp = net.request("/trustpromo".to_string(), encoded_req).await;
    let decoded_resp: trust_promotion::Response = serde_json::from_slice(&encoded_resp).unwrap();
    let migration_cred = trust_promotion::handle_response(state, decoded_resp).unwrap();
    migration_cred
}

// Promote from untrusted (trust level 0) to trusted (trust level 1)
pub async fn trust_migration(
    net: &dyn Networking,
    lox_cred: &lox::cred::Lox,
    migration_cred: &lox::cred::Migration,
    lox_pub: &IssuerPubKey,
    migration_pub: &IssuerPubKey,
) -> lox::cred::Lox {
    let (req, state) =
        migration::request(lox_cred, migration_cred, lox_pub, migration_pub).unwrap();
    let encoded_req: Vec<u8> = serde_json::to_vec(&req).unwrap();
    let encoded_resp = net.request("/trustmig".to_string(), encoded_req).await;
    let decoded_resp: migration::Response = serde_json::from_slice(&encoded_resp).unwrap();
    let cred = migration::handle_response(state, decoded_resp, lox_pub).unwrap();
    cred
}

// Increase trust from at least level 1 to higher levels
pub async fn level_up(
    net: &dyn Networking,
    lox_cred: &lox::cred::Lox,
    encbuckets: &Vec<[u8; ENC_BUCKET_BYTES]>,
    lox_pub: &IssuerPubKey,
    reachability_pub: &IssuerPubKey,
) -> lox::cred::Lox {
    // Read the bucket in the credential to get today's Bucket
    // Reachability credential

    let (id, key) = lox::bridge_table::from_scalar(lox_cred.bucket).unwrap();
    let bucket =
        lox::bridge_table::BridgeTable::decrypt_bucket(id, &key, &encbuckets[id as usize]).unwrap();
    let reachcred = bucket.1.unwrap();

    // FOR TESTING ONLY
    let time_offset = get_time_offset() + 60 * 60 * 24 * 85;
    save_time_offset(&time_offset);

    // Use the Bucket Reachability credential to advance to the next
    // level
    let (req, state) = level_up::request(
        lox_cred,
        &reachcred,
        lox_pub,
        reachability_pub,
        //today(Duration::ZERO),
        today(Duration::from_secs(time_offset.into())), // FOR TESTING ONLY
    )
    .unwrap();
    let encoded_req: Vec<u8> = serde_json::to_vec(&req).unwrap();
    let encoded_resp = net.request("/levelup".to_string(), encoded_req).await;
    let decoded_resp: level_up::Response = serde_json::from_slice(&encoded_resp).unwrap();
    let cred = level_up::handle_response(state, decoded_resp, lox_pub).unwrap();
    cred
}

// Request an Invitation credential to give to a friend
pub async fn issue_invite(
    net: &dyn Networking,
    lox_cred: &lox::cred::Lox,
    encbuckets: &Vec<[u8; ENC_BUCKET_BYTES]>,
    lox_pub: &IssuerPubKey,
    reachability_pub: &IssuerPubKey,
    invitation_pub: &IssuerPubKey,
) -> (lox::cred::Lox, lox::cred::Invitation) {
    // Read the bucket in the credential to get today's Bucket
    // Reachability credential

    let (id, key) = lox::bridge_table::from_scalar(lox_cred.bucket).unwrap();
    let bucket =
        lox::bridge_table::BridgeTable::decrypt_bucket(id, &key, &encbuckets[id as usize]).unwrap();
    let reachcred = bucket.1.unwrap();

    let (req, state) = issue_invite::request(
        lox_cred,
        &reachcred,
        lox_pub,
        reachability_pub,
        today(Duration::ZERO),
    )
    .unwrap();
    let encoded_req: Vec<u8> = serde_json::to_vec(&req).unwrap();
    let encoded_resp = net.request("/issueinvite".to_string(), encoded_req).await;
    let decoded_resp: issue_invite::Response = serde_json::from_slice(&encoded_resp).unwrap();
    let (cred, invite) =
        issue_invite::handle_response(state, decoded_resp, lox_pub, invitation_pub).unwrap();
    (cred, invite)
}

// Redeem an Invitation credential to start at trust level 1
pub async fn redeem_invite(
    net: &dyn Networking,
    invite: &lox::cred::Invitation,
    lox_pub: &IssuerPubKey,
    invitation_pub: &IssuerPubKey,
) -> lox::cred::Lox {
    let (req, state) =
        redeem_invite::request(invite, invitation_pub, today(Duration::ZERO)).unwrap();
    let encoded_req: Vec<u8> = serde_json::to_vec(&req).unwrap();
    let encoded_resp = net.request("/redeem".to_string(), encoded_req).await;
    let decoded_resp: redeem_invite::Response = serde_json::from_slice(&encoded_resp).unwrap();
    let cred = redeem_invite::handle_response(state, decoded_resp, lox_pub).unwrap();
    cred
}

// Check for a migration credential to move to a new bucket
pub async fn check_blockage(
    net: &dyn Networking,
    lox_cred: &lox::cred::Lox,
    lox_pub: &IssuerPubKey,
) -> lox::cred::Migration {
    let (req, state) = check_blockage::request(lox_cred, lox_pub).unwrap();
    let encoded_req: Vec<u8> = serde_json::to_vec(&req).unwrap();
    let encoded_resp = net.request("/checkblockage".to_string(), encoded_req).await;
    let decoded_resp: check_blockage::Response = serde_json::from_slice(&encoded_resp).unwrap();
    let migcred = check_blockage::handle_response(state, decoded_resp).unwrap();
    migcred
}

// Migrate to a new bucket (must be level >= 3)
pub async fn blockage_migration(
    net: &dyn Networking,
    lox_cred: &lox::cred::Lox,
    migcred: &lox::cred::Migration,
    lox_pub: &IssuerPubKey,
    migration_pub: &IssuerPubKey,
) -> lox::cred::Lox {
    let (req, state) =
        blockage_migration::request(lox_cred, migcred, lox_pub, migration_pub).unwrap();
    let encoded_req: Vec<u8> = serde_json::to_vec(&req).unwrap();
    let encoded_resp = net
        .request("/blockagemigration".to_string(), encoded_req)
        .await;
    let decoded_resp: blockage_migration::Response = serde_json::from_slice(&encoded_resp).unwrap();
    let cred = blockage_migration::handle_response(state, decoded_resp, lox_pub).unwrap();
    cred
}