added 'deterministic_route_selection' for sphinx packet route selection (#5157)

* added 'deterministic_route_selection' for sphinx packet route selection

* clippy + wasm

* Switch to ChaCha8Rng for deterministic route generation

---------

Co-authored-by: durch <durch@users.noreply.github.com>

common/client-core/config-types/src/lib.rs

@@ -381,13 +381,16 @@ pub struct Traffic {
     /// poisson distribution.
     pub disable_main_poisson_packet_distribution: bool,
 
+    /// Specify whether route selection should be determined by the packet header.
+    pub deterministic_route_selection: bool,
+
     /// Specifies the packet size used for sent messages.
     /// Do not override it unless you understand the consequences of that change.
     pub primary_packet_size: PacketSize,
 
     /// Specifies the optional auxiliary packet size for optimizing message streams.
     /// Note that its use decreases overall anonymity.
-    /// Do not set it it unless you understand the consequences of that change.
+    /// Do not set it unless you understand the consequences of that change.
     pub secondary_packet_size: Option<PacketSize>,
 
     pub packet_type: PacketType,
@@ -412,6 +415,7 @@ impl Default for Traffic {
             average_packet_delay: DEFAULT_AVERAGE_PACKET_DELAY,
             message_sending_average_delay: DEFAULT_MESSAGE_STREAM_AVERAGE_DELAY,
             disable_main_poisson_packet_distribution: false,
+            deterministic_route_selection: false,
             primary_packet_size: PacketSize::RegularPacket,
             secondary_packet_size: None,
             packet_type: PacketType::Mix,

common/client-core/config-types/src/old/v5.rs

@@ -111,6 +111,7 @@ impl From<ConfigV5> for Config {
                     primary_packet_size: value.debug.traffic.primary_packet_size,
                     secondary_packet_size: value.debug.traffic.secondary_packet_size,
                     packet_type: value.debug.traffic.packet_type,
+                    ..Default::default()
                 },
                 cover_traffic: CoverTraffic {
                     loop_cover_traffic_average_delay: value

common/client-core/src/client/real_messages_control/message_handler.rs

@@ -91,6 +91,9 @@ pub(crate) struct Config {
     /// and surb-based are going to be sent.
     sender_address: Recipient,
 
+    /// Specify whether route selection should be determined by the packet header.
+    deterministic_route_selection: bool,
+
     /// Average delay a data packet is going to get delay at a single mixnode.
     average_packet_delay: Duration,
 
@@ -114,10 +117,12 @@ impl Config {
         sender_address: Recipient,
         average_packet_delay: Duration,
         average_ack_delay: Duration,
+        deterministic_route_selection: bool,
     ) -> Self {
         Config {
             ack_key,
             sender_address,
+            deterministic_route_selection,
             average_packet_delay,
             average_ack_delay,
             num_mix_hops: DEFAULT_NUM_MIX_HOPS,
@@ -176,6 +181,7 @@ where
     {
         let message_preparer = MessagePreparer::new(
             rng,
+            config.deterministic_route_selection,
             config.sender_address,
             config.average_packet_delay,
             config.average_ack_delay,

common/client-core/src/client/real_messages_control/mod.rs

@@ -97,6 +97,7 @@ impl<'a> From<&'a Config> for message_handler::Config {
             cfg.self_recipient,
             cfg.traffic.average_packet_delay,
             cfg.acks.average_ack_delay,
+            cfg.traffic.deterministic_route_selection,
         )
         .with_custom_primary_packet_size(cfg.traffic.primary_packet_size)
         .with_custom_secondary_packet_size(cfg.traffic.secondary_packet_size)

common/node-tester-utils/src/tester.rs

@@ -29,6 +29,9 @@ pub struct NodeTester<R> {
 
     packet_size: PacketSize,
 
+    /// Specify whether route selection should be determined by the packet header.
+    deterministic_route_selection: bool,
+
     /// Average delay a data packet is going to get delay at a single mixnode.
     average_packet_delay: Duration,
 
@@ -48,11 +51,13 @@ impl<R> NodeTester<R>
 where
     R: Rng + CryptoRng,
 {
+    #[allow(clippy::too_many_arguments)]
     pub fn new(
         rng: R,
         base_topology: NymTopology,
         self_address: Option<Recipient>,
         packet_size: PacketSize,
+        deterministic_route_selection: bool,
         average_packet_delay: Duration,
         average_ack_delay: Duration,
         ack_key: Arc<AckKey>,
@@ -62,6 +67,7 @@ where
             base_topology,
             self_address,
             packet_size,
+            deterministic_route_selection,
             average_packet_delay,
             average_ack_delay,
             num_mix_hops: DEFAULT_NUM_MIX_HOPS,
@@ -289,10 +295,18 @@ where
 impl<R: CryptoRng + Rng> FragmentPreparer for NodeTester<R> {
     type Rng = R;
 
+    fn deterministic_route_selection(&self) -> bool {
+        self.deterministic_route_selection
+    }
+
     fn rng(&mut self) -> &mut Self::Rng {
         &mut self.rng
     }
 
+    fn nonce(&self) -> i32 {
+        1
+    }
+
     fn num_mix_hops(&self) -> u8 {
         self.num_mix_hops
     }
@@ -304,8 +318,4 @@ impl<R: CryptoRng + Rng> FragmentPreparer for NodeTester<R> {
     fn average_ack_delay(&self) -> Duration {
         self.average_ack_delay
     }
-
-    fn nonce(&self) -> i32 {
-        1
-    }
 }

common/nymsphinx/src/preparer/mod.rs

@@ -18,7 +18,7 @@ use nym_sphinx_params::{PacketType, ReplySurbKeyDigestAlgorithm, DEFAULT_NUM_MIX
 use nym_sphinx_types::{Delay, NymPacket};
 use nym_topology::{NymTopology, NymTopologyError};
 use rand::{CryptoRng, Rng, SeedableRng};
-use rand_chacha::ChaCha20Rng;
+use rand_chacha::ChaCha8Rng;
 
 use nym_sphinx_chunking::monitoring;
 use std::time::Duration;
@@ -51,6 +51,7 @@ impl From<PreparedFragment> for MixPacket {
 pub trait FragmentPreparer {
     type Rng: CryptoRng + Rng;
 
+    fn deterministic_route_selection(&self) -> bool;
     fn rng(&mut self) -> &mut Self::Rng;
     fn nonce(&self) -> i32;
     fn num_mix_hops(&self) -> u8;
@@ -201,9 +202,7 @@ pub trait FragmentPreparer {
         // could perform diffie-hellman with its own keys followed by a kdf to re-derive
         // the packet encryption key
 
-        let seed = fragment.seed().wrapping_mul(self.nonce());
-        let mut rng = ChaCha20Rng::seed_from_u64(seed as u64);
-
+        let fragment_header = fragment.header();
         let destination = packet_recipient.gateway();
         let hops = mix_hops.unwrap_or(self.num_mix_hops());
         monitoring::fragment_sent(&fragment, self.nonce(), *destination, hops);
@@ -241,8 +240,18 @@ pub trait FragmentPreparer {
         };
 
         // generate pseudorandom route for the packet
-        log::trace!("Preparing chunk for sending with {} mix hops", hops);
-        let route = topology.random_route_to_gateway(&mut rng, hops, destination)?;
+        log::trace!("Preparing chunk for sending with {hops} mix hops");
+        let route = if self.deterministic_route_selection() {
+            log::trace!("using deterministic route selection");
+            let seed = fragment_header.seed().wrapping_mul(self.nonce());
+            let mut rng = ChaCha8Rng::seed_from_u64(seed as u64);
+            topology.random_route_to_gateway(&mut rng, hops, destination)?
+        } else {
+            log::trace!("using pseudorandom route selection");
+            let mut rng = self.rng();
+            topology.random_route_to_gateway(&mut rng, hops, destination)?
+        };
+
         let destination = packet_recipient.as_sphinx_destination();
 
         // including set of delays
@@ -313,6 +322,9 @@ pub struct MessagePreparer<R> {
     /// Instance of a cryptographically secure random number generator.
     rng: R,
 
+    /// Specify whether route selection should be determined by the packet header.
+    deterministic_route_selection: bool,
+
     /// Address of this client which also represent an address to which all acknowledgements
     /// and surb-based are going to be sent.
     sender_address: Recipient,
@@ -336,6 +348,7 @@ where
 {
     pub fn new(
         rng: R,
+        deterministic_route_selection: bool,
         sender_address: Recipient,
         average_packet_delay: Duration,
         average_ack_delay: Duration,
@@ -344,6 +357,7 @@ where
         let nonce = rng.gen();
         MessagePreparer {
             rng,
+            deterministic_route_selection,
             sender_address,
             average_packet_delay,
             average_ack_delay,
@@ -457,10 +471,18 @@ where
 impl<R: CryptoRng + Rng> FragmentPreparer for MessagePreparer<R> {
     type Rng = R;
 
+    fn deterministic_route_selection(&self) -> bool {
+        self.deterministic_route_selection
+    }
+
     fn rng(&mut self) -> &mut Self::Rng {
         &mut self.rng
     }
 
+    fn nonce(&self) -> i32 {
+        self.nonce
+    }
+
     fn num_mix_hops(&self) -> u8 {
         self.num_mix_hops
     }
@@ -472,10 +494,6 @@ impl<R: CryptoRng + Rng> FragmentPreparer for MessagePreparer<R> {
     fn average_ack_delay(&self) -> Duration {
         self.average_ack_delay
     }
-
-    fn nonce(&self) -> i32 {
-        self.nonce
-    }
 }
 
 /*

common/wasm/client-core/src/config/mod.rs

@@ -156,6 +156,9 @@ pub struct TrafficWasm {
     /// a loop cover message is sent instead in order to preserve the rate.
     pub message_sending_average_delay_ms: u32,
 
+    /// Specify whether route selection should be determined by the packet header.
+    pub deterministic_route_selection: bool,
+
     /// Controls whether the main packet stream constantly produces packets according to the predefined
     /// poisson distribution.
     pub disable_main_poisson_packet_distribution: bool,
@@ -190,6 +193,7 @@ impl From<TrafficWasm> for ConfigTraffic {
             message_sending_average_delay: Duration::from_millis(
                 traffic.message_sending_average_delay_ms as u64,
             ),
+            deterministic_route_selection: traffic.deterministic_route_selection,
             disable_main_poisson_packet_distribution: traffic
                 .disable_main_poisson_packet_distribution,
             primary_packet_size: PacketSize::RegularPacket,
@@ -205,6 +209,7 @@ impl From<ConfigTraffic> for TrafficWasm {
             average_packet_delay_ms: traffic.average_packet_delay.as_millis() as u32,
             message_sending_average_delay_ms: traffic.message_sending_average_delay.as_millis()
                 as u32,
+            deterministic_route_selection: traffic.deterministic_route_selection,
             disable_main_poisson_packet_distribution: traffic
                 .disable_main_poisson_packet_distribution,
             use_extended_packet_size: traffic.secondary_packet_size.is_some(),

common/wasm/client-core/src/config/override.rs

@@ -83,6 +83,10 @@ pub struct TrafficWasmOverride {
     #[tsify(optional)]
     pub message_sending_average_delay_ms: Option<u32>,
 
+    /// Specify whether route selection should be determined by the packet header.
+    #[tsify(optional)]
+    pub deterministic_route_selection: Option<bool>,
+
     /// Controls whether the main packet stream constantly produces packets according to the predefined
     /// poisson distribution.
     #[tsify(optional)]
@@ -108,6 +112,9 @@ impl From<TrafficWasmOverride> for TrafficWasm {
             message_sending_average_delay_ms: value
                 .message_sending_average_delay_ms
                 .unwrap_or(def.message_sending_average_delay_ms),
+            deterministic_route_selection: value
+                .deterministic_route_selection
+                .unwrap_or(def.deterministic_route_selection),
             disable_main_poisson_packet_distribution: value
                 .disable_main_poisson_packet_distribution
                 .unwrap_or(def.disable_main_poisson_packet_distribution),

nym-api/src/network_monitor/monitor/preparer.rs

@@ -121,6 +121,7 @@ impl PacketPreparer {
             test_route.topology().clone(),
             self_address,
             PacketSize::RegularPacket,
+            false,
             DEFAULT_AVERAGE_PACKET_DELAY,
             DEFAULT_AVERAGE_ACK_DELAY,
             self.ack_key.clone(),

nym-wallet/Cargo.lock

@@ -3518,7 +3518,7 @@ dependencies = [
 
 [[package]]
 name = "nym_wallet"
-version = "1.2.14"
+version = "1.2.15"
 dependencies = [
  "async-trait",
  "base64 0.13.1",

wasm/node-tester/src/tester.rs

@@ -229,6 +229,7 @@ impl NymNodeTesterBuilder {
             self.base_topology,
             Some(address(&managed_keys, gateway_identity)),
             PacketSize::default(),
+            false,
             Duration::from_millis(5),
             Duration::from_millis(5),
             managed_keys.ack_key(),