vinteumorg · Davidson-Souza · Jul 31, 2024 · Jul 31, 2024
diff --git a/crates/floresta-electrum/src/electrum_protocol.rs b/crates/floresta-electrum/src/electrum_protocol.rs
@@ -1018,6 +1018,7 @@ mod test {
             max_inflight: 20,
             assume_utreexo: None,
             backfill: false,
+            filter_start_height: None,
         };
 
         let chain_provider: UtreexoNode<RunningNode, Arc<ChainState<KvChainStore>>> =

diff --git a/crates/floresta-wire/src/p2p_wire/mod.rs b/crates/floresta-wire/src/p2p_wire/mod.rs
@@ -55,6 +55,15 @@ pub struct UtreexoNodeConfig {
     /// is that we are vulnerable to a fraud proof attack for a few hours, but we can spot it
     /// and react in a couple of hours at most, so the attack window is very small.
     pub backfill: bool,
+    /// If we are using network-provided block filters, we may not need to download the whole
+    /// chain of filters, as our wallets may not have been created at the beginning of the chain.
+    /// With this option, we can make a rough estimate of the block height we need to start
+    /// and only download the filters from that height.
+    ///
+    /// If the value is negative, it's relative to the current tip. For example, if the current
+    /// tip is at height 1000, and we set this value to -100, we will start downloading filters
+    /// from height 900.
+    pub filter_start_height: Option<i32>,
 }
 
 impl Default for UtreexoNodeConfig {
@@ -71,6 +80,7 @@ impl Default for UtreexoNodeConfig {
             proxy: None,
             backfill: false,
             assume_utreexo: None,
+            filter_start_height: None,
         }
     }
 }

diff --git a/crates/floresta-wire/src/p2p_wire/running_node.rs b/crates/floresta-wire/src/p2p_wire/running_node.rs
@@ -474,9 +474,21 @@ where
             return Ok(());
         };
 
-        let height = filters.get_height()?;
+        let mut height = filters.get_height()?;
         let best_height = self.chain.get_height()?;
 
+        if height == 0 {
+            let user_height = self.config.filter_start_height.unwrap_or(0);
+
+            height = if user_height < 0 {
+                best_height.saturating_sub(user_height.unsigned_abs())
+            } else {
+                user_height as u32
+            };
+
+            filters.save_height(height)?;
+        }
+
         if height >= best_height {
             return Ok(());
         }
@@ -812,14 +824,12 @@ where
                     debug!("Got a block filter for block {hash} from peer {peer}");
 
                     if let Some(filters) = self.block_filters.as_ref() {
-                        filters.push_filter(filter)?;
-
                         let current_height = filters.get_height()?;
                         let Some(this_height) = self.chain.get_block_height(&hash)? else {
                             warn!("Filter for block {} received, but we don't have it", hash);
                             return Ok(());
                         };
-                        filters.save_height(current_height + 1)?;
+
                         // we expect to receive them in order
                         if current_height + 1 != this_height {
                             warn!(
@@ -831,6 +841,9 @@ where
                             return Ok(());
                         }
 
+                        filters.save_height(current_height + 1)?;
+                        filters.push_filter(filter)?;
+
                         if self.last_filter == hash {
                             self.inflight.remove(&InflightRequests::GetFilters);
                             self.download_filters().await?;

diff --git a/florestad/src/cli.rs b/florestad/src/cli.rs
@@ -138,5 +138,8 @@ pub enum Commands {
         rpc_address: Option<String>,
         #[arg(long)]
         electrum_address: Option<String>,
+        #[arg(long)]
+        /// Download block filters starting at this height. Negative numbers are relative to the current tip.
+        filters_start_height: Option<i32>,
     },
 }
diff --git a/florestad/src/florestad.rs b/florestad/src/florestad.rs
@@ -107,6 +107,14 @@ pub struct Config {
     /// is very inefficient and resource/time consuming. But keep in mind that filters will take
     /// up disk space.
     pub cfilters: bool,
+    /// If we are using block filters, we may not need to download the whole chain of filters, as
+    /// our wallets may not have been created at the beginning of the chain. With this option, we
+    /// can make a rough estimate of the block height we need to start downloading filters.
+    ///
+    /// If the value is negative, it's relative to the current tip. For example, if the current tip
+    /// is at height 1000, and we set this value to -100, we will start downloading filters from
+    /// height 900.
+    pub filters_start_height: Option<i32>,
     #[cfg(feature = "zmq-server")]
     /// The address to listen to for our ZMQ server
     ///
@@ -335,6 +343,7 @@ impl Florestad {
             max_inflight: 20,
             assume_utreexo,
             backfill: false,
+            filter_start_height: self.config.filters_start_height,
         };
 
         // Chain Provider (p2p)

diff --git a/florestad/src/main.rs b/florestad/src/main.rs
@@ -45,6 +45,7 @@ async fn main() {
             connect,
             rpc_address,
             electrum_address,
+            filters_start_height,
         }) => Config {
             debug: params.debug,
             data_dir,
@@ -65,6 +66,7 @@ async fn main() {
             log_to_file: true,
             log_to_stdout: true,
             assume_utreexo: true,
+            filters_start_height,
         },
 
         // We may have more commands here, like setup and dump wallet