Filtering DNS seed by features

common/src/dns.rs

@@ -0,0 +1,108 @@
+//! Seed resolution.
+use log::debug;
+use std::net::{SocketAddr, ToSocketAddrs};
+
+use crate::network::Network;
+
+/// DNS feature
+#[derive(Debug, Copy, Clone)]
+pub enum SeedFeature {
+    /// x1, Full Node
+    NODE_NETWORK,
+    /// x5, all include in x1 plus Node network
+    NODE_BLOOM,
+    /// x9, all included in x1 plus Node Witness
+    NODE_WITNESS,
+    /// xd (aka x13), all included in x9 and x5
+    FULL_NODE,
+}
+
+impl Default for SeedFeature {
+    fn default() -> Self {
+        Self::NODE_NETWORK
+    }
+}
+
+impl SeedFeature {
+    pub fn as_code(&self) -> &'static str {
+        match self {
+            Self::NODE_NETWORK => &"x1",
+            Self::NODE_BLOOM => &"x5",
+            Self::NODE_WITNESS => &"x9",
+            Self::FULL_NODE => &"xd",
+        }
+    }
+}
+
+/// Seeds implementation
+pub struct Seeds<'a> {
+    /// The network to work load the dns
+    network: Network,
+    /// The default port of the node
+    port: u16,
+    /// List of feature supported by nakamoto
+    features: &'a [SeedFeature],
+}
+
+impl<'a> Seeds<'a> {
+    /// Create a new seed with the requirements
+    pub fn new(network: Network, port: u16, features: &'a [SeedFeature]) -> Self {
+        Seeds {
+            network,
+            port,
+            features,
+        }
+    }
+
+    pub fn load(&self) -> Vec<SocketAddr> {
+        let seeds = self.from_network();
+        self.filter_by_feature(seeds)
+    }
+
+    fn from_network(&self) -> &[&str] {
+        match self.network {
+            Network::Mainnet => &[
+                "seed.bitcoin.sipa.be",          // Pieter Wuille
+                "dnsseed.bluematt.me",           // Matt Corallo
+                "dnsseed.bitcoin.dashjr.org",    // Luke Dashjr
+                "seed.bitcoinstats.com",         // Christian Decker
+                "seed.bitcoin.jonasschnelli.ch", // Jonas Schnelli
+                "seed.btc.petertodd.org",        // Peter Todd
+                "seed.bitcoin.sprovoost.nl",     // Sjors Provoost
+                "dnsseed.emzy.de",               // Stephan Oeste
+                "seed.bitcoin.wiz.biz",          // Jason Maurice
+                "seed.cloudhead.io",             // Alexis Sellier
+            ],
+            Network::Testnet => &[
+                "testnet-seed.bitcoin.jonasschnelli.ch",
+                "seed.tbtc.petertodd.org",
+                "seed.testnet.bitcoin.sprovoost.nl",
+                "testnet-seed.bluematt.me",
+            ],
+            Network::Regtest => &[], // No seeds
+        }
+    }
+
+    fn filter_by_feature(&self, seed_list: &[&str]) -> Vec<SocketAddr> {
+        let mut seeds_addr = Vec::new();
+        for feature in self.features {
+            let feature_code = feature.as_code();
+            debug!("Filtering by feature {}", feature_code);
+
+            for seed in seed_list {
+                let sub_seed = format!("{}.{}:{}", feature_code, seed, self.port);
+                debug!("Sub seed {} checking ...", sub_seed);
+                if let Ok(hosts) = (*sub_seed).to_socket_addrs() {
+                    for host in hosts {
+                        seeds_addr.push(host);
+                    }
+                } else {
+                    // we admit the failure at this point because not all the seed
+                    // support all the feature.
+                    debug!("Seed {} doesn't support feature {}", seed, feature_code);
+                }
+            }
+        }
+        seeds_addr
+    }
+}

common/src/lib.rs

@@ -3,9 +3,9 @@
 #![deny(missing_docs, unsafe_code)]
 pub mod block;
 pub mod collections;
+mod dns;
 pub mod network;
 pub mod p2p;
-
 pub use nonempty;
 
 /// Return the function path at the current source location.

common/src/network.rs

@@ -9,6 +9,7 @@ use bitcoin_hashes::hex::FromHex;
 use bitcoin_hashes::sha256d;
 
 use crate::block::Height;
+use crate::dns;
 
 /// Peer services supported by nakamoto.
 #[derive(Debug, Copy, Clone)]

common/src/p2p/peer.rs

@@ -45,6 +45,8 @@ pub trait Store {
         seeds: impl Iterator<Item = S>,
         source: Source,
     ) -> io::Result<()> {
+        // TODO(vincenzopalazzo): move this logic inside the dns module in comm
+        // and use this method to add only the list of the socket addrs.
         let mut error = None;
         let mut success = false;