Add privacy and validation options in the config

protocols/gossipsub/src/config.rs

@@ -19,9 +19,51 @@
 // DEALINGS IN THE SOFTWARE.
 
 use crate::protocol::{GossipsubMessage, MessageId};
+use log::warn;
 use std::borrow::Cow;
 use std::time::Duration;
 
+/// The types of privacy settings that can be employed by gossipsub. These are related to how
+/// anonymous the publisher of the message would like to be.
+#[derive(Debug, Clone)]
+pub enum PrivacySetting {
+    /// This is the default setting. The PeerId publishing the message will be broadcast with the
+    /// message along with a random sequence number.
+    None,
+    /// A randomized `PeerId` will be used as the publisher of a message.
+    ///
+    /// NOTE: This mode cannot be used in conjunction with message signing.
+    RandomAuthor,
+    /// The author of the message and the sequence numbers are excluded from the message.
+    ///
+    /// NOTE: This mode cannot be used in conjunction with message signing. Also not that excluding
+    /// these fields may make these messages invalid by other nodes who enforce validation of these
+    /// fields. See [`ValidationSetting`] for how to customise this for rust-libp2p gossipsub.
+    Anonymous,
+}
+
+/// The types of message validation that can be employed by gossipsub.
+#[derive(Debug, Clone)]
+pub enum ValidationSetting {
+    /// This is the default setting. This requires the message author to be a valid `PeerId` and to
+    /// be present as well as the sequence number. All messages must have valid signatures.
+    ///
+    /// NOTE: This setting will reject messages from nodes using `PrivacySetting::Anonymous` and
+    /// all messages that do not have signatures.
+    Strict,
+    /// This setting permits messages that have no author, sequence number or signature. If any of
+    /// these fields exist in the message these are validated.
+    Permissive,
+    /// This setting requires the author, sequence number and signature fields of a message to be
+    /// empty. Any message that contains these fields is considered invalid.
+    Anonymous,
+    /// This setting does not check the author, sequence number or signature fields of incoming
+    /// messages. If these fields contain data, they are simply ignored.
+    ///
+    /// NOTE: This setting will consider messages with invalid signatures as valid messages.
+    None,
+}
+
 /// Configuration parameters that define the performance of the gossipsub network.
 #[derive(Clone)]
 pub struct GossipsubConfig {
@@ -69,6 +111,14 @@ pub struct GossipsubConfig {
     /// once validated (default is `false`).
     pub manual_propagation: bool,
 
+    /// Determines the level of privacy for the node when publishing a message. See [`PrivacySetting`] for
+    /// the available types. The default is PrivacySetting::None.
+    pub privacy_mode: PrivacySetting,
+
+    /// Determines the level of validation used when receiving messages. See [`ValidationSetting`]
+    /// for the available types. The default is ValidationSetting::Strict.
+    pub validation_mode: ValidationSetting,
+
     /// A user-defined function allowing the user to specify the message id of a gossipsub message.
     /// The default value is to concatenate the source peer id with a sequence number. Setting this
     /// parameter allows the user to address packets arbitrarily. One example is content based
@@ -96,6 +146,8 @@ impl Default for GossipsubConfig {
             max_transmit_size: 2048,
             hash_topics: false, // default compatibility with floodsub
             manual_propagation: false,
+            privacy_mode: PrivacySetting::None,
+            validation_mode: ValidationSetting::Strict,
             message_id_fn: |message| {
                 // default message id is: source + sequence number
                 let mut source_string = message.source.to_base58();
@@ -229,6 +281,26 @@ impl GossipsubConfigBuilder {
         self
     }
 
+    /// Determines the level of privacy for the node when publishing a message. See [`PrivacySetting`] for
+    /// the available types.
+    pub fn privacy_mode(&mut self, privacy_setting: PrivacySetting) -> &mut Self {
+        self.config.privacy_mode = privacy_setting;
+
+        // warn the user about odd combinations of privacy/validation
+        self.check_privacy_validation();
+        self
+    }
+
+    /// Determines the level of validation used when receiving messages. See [`ValidationSetting`]
+    /// for the available types. The default is ValidationSetting::Strict.
+    pub fn validation_mode(&mut self, validation_setting: ValidationSetting) -> &mut Self {
+        self.config.validation_mode = validation_setting;
+
+        // warn the user about odd combinations of privacy/validation
+        self.check_privacy_validation();
+        self
+    }
+
     /// A user-defined function allowing the user to specify the message id of a gossipsub message.
     /// The default value is to concatenate the source peer id with a sequence number. Setting this
     /// parameter allows the user to address packets arbitrarily. One example is content based
@@ -246,6 +318,27 @@ impl GossipsubConfigBuilder {
     pub fn build(&self) -> GossipsubConfig {
         self.config.clone()
     }
+
+    // Warns the user for odd combinations of privacy and validation.
+    fn check_privacy_validation(&self) {
+        match (&self.config.validation_mode, &self.config.privacy_mode) {
+            (ValidationSetting::Strict, PrivacySetting::RandomAuthor) => warn!(
+                "Messages will be
+            published unsigned and incoming unsigned messages will be rejected. Consider adjusting
+            the validation or privacy settings in the config"
+            ),
+            (ValidationSetting::Strict, PrivacySetting::Anonymous) => {
+                warn!("Messages will not be signed or contain an author, but incoming messages requires this. Consider adjusting the validation or privacy settings in the config")
+            }
+            (ValidationSetting::Anonymous, PrivacySetting::None) => {
+                warn!("Published messages contain an author but incoming messages with an author will be rejected. Consider adjusting the validation or privacy settings in the config")
+            }
+            (ValidationSetting::Anonymous, PrivacySetting::RandomAuthor) => {
+                warn!("Published messages contain an author but incoming messages with an author will be rejected. Consider adjusting the validation or privacy settings in the config")
+            }
+            (_, _) => {}
+        }
+    }
 }
 
 impl std::fmt::Debug for GossipsubConfig {