From: Matt Corallo <git@bluematt.me>
Date: Fri, 23 Aug 2019 00:19:24 +0000 (-0400)
Subject: Filter DNS results by common ASN
X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=commitdiff_plain;h=ecd6d703b476c659c343d0e2c034c5b094645ce5;p=dnsseed-rust

Filter DNS results by common ASN
---

diff --git a/Cargo.toml b/Cargo.toml
index 4c8459f..3f8225a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,6 +7,7 @@ edition = "2018"
 [dependencies]
 bitcoin = "0.19"
 bitcoin_hashes = "0.7"
+bgp-rs = { git = "https://github.com/TheBlueMatt/bgp-rs", rev = "330837f97b7e8e5ea3db66a4b3512863e54da8b0" }
 tokio = "0.1"
 bytes = "0.4"
 futures = "0.1"
diff --git a/src/bgp_client.rs b/src/bgp_client.rs
new file mode 100644
index 0000000..f9ab0ae
--- /dev/null
+++ b/src/bgp_client.rs
@@ -0,0 +1,293 @@
+use std::sync::{Arc, Mutex};
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::cmp;
+use std::ops::Bound::Included;
+use std::collections::BTreeMap;
+use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr};
+use std::time::{Duration, Instant};
+
+use bgp_rs::{AFI, SAFI, AddPathDirection, Open, OpenCapability, OpenParameter, NLRIEncoding, PathAttribute};
+use bgp_rs::Capabilities;
+use bgp_rs::{ASPath, Segment};
+use bgp_rs::Message;
+use bgp_rs::Reader;
+
+use tokio::prelude::*;
+use tokio::codec;
+use tokio::codec::Framed;
+use tokio::net::TcpStream;
+use tokio::timer::Delay;
+
+use futures::sync::mpsc;
+
+use crate::printer::Printer;
+
+pub struct RoutingTable {
+	v4_table: BTreeMap<(Ipv4Addr, u8, u32), Arc<Vec<PathAttribute>>>,
+	v6_table: BTreeMap<(Ipv6Addr, u8, u32), Arc<Vec<PathAttribute>>>,
+}
+
+impl RoutingTable {
+	fn new() -> Self {
+		Self {
+			v4_table: BTreeMap::new(),
+			v6_table: BTreeMap::new(),
+		}
+	}
+
+	fn get_route_attrs(&self, ip: IpAddr) -> Vec<Arc<Vec<PathAttribute>>> {
+		macro_rules! lookup_res {
+			($addrty: ty, $addr: expr, $table: expr, $addr_bits: expr) => { {
+				let mut res = Vec::new();
+				//TODO: Optimize this!
+				for i in (0..($addr_bits + 1)).rev() {
+					let mut lookup = $addr.octets();
+					for b in 0..(i / 8) {
+						lookup[lookup.len() - b] = 0;
+					}
+					lookup[lookup.len() - (i/8)] &= !(((1u16 << (i % 8)) - 1) as u8);
+					let lookup_addr = <$addrty>::from(lookup);
+					for attrs in $table.range((Included((lookup_addr, $addr_bits, 0)), Included((lookup_addr, $addr_bits, std::u32::MAX)))) {
+						res.push(Arc::clone(&attrs.1));
+					}
+					if !res.is_empty() { break; }
+				}
+				res
+			} }
+		}
+		match ip {
+			IpAddr::V4(v4a) => lookup_res!(Ipv4Addr, v4a, self.v4_table, 32),
+			IpAddr::V6(v6a) => lookup_res!(Ipv6Addr, v6a, self.v6_table, 128)
+		}
+	}
+
+	fn withdraw(&mut self, route: NLRIEncoding) {
+		match route {
+			NLRIEncoding::IP(p) => {
+				let (ip, len) = <(IpAddr, u8)>::from(&p);
+				match ip {
+					IpAddr::V4(v4a) => self.v4_table.remove(&(v4a, len, 0)),
+					IpAddr::V6(v6a) => self.v6_table.remove(&(v6a, len, 0)),
+				}
+			},
+			NLRIEncoding::IP_WITH_PATH_ID((p, id)) => {
+				let (ip, len) = <(IpAddr, u8)>::from(&p);
+				match ip {
+					IpAddr::V4(v4a) => self.v4_table.remove(&(v4a, len, id)),
+					IpAddr::V6(v6a) => self.v6_table.remove(&(v6a, len, id)),
+				}
+			},
+			NLRIEncoding::IP_MPLS(_) => None,
+		};
+	}
+
+	fn announce(&mut self, route: NLRIEncoding, attrs: Arc<Vec<PathAttribute>>) {
+		match route {
+			NLRIEncoding::IP(p) => {
+				let (ip, len) = <(IpAddr, u8)>::from(&p);
+				match ip {
+					IpAddr::V4(v4a) => self.v4_table.insert((v4a, len, 0), attrs),
+					IpAddr::V6(v6a) => self.v6_table.insert((v6a, len, 0), attrs),
+				}
+			},
+			NLRIEncoding::IP_WITH_PATH_ID((p, id)) => {
+				let (ip, len) = <(IpAddr, u8)>::from(&p);
+				match ip {
+					IpAddr::V4(v4a) => self.v4_table.insert((v4a, len, id), attrs),
+					IpAddr::V6(v6a) => self.v6_table.insert((v6a, len, id), attrs),
+				}
+			},
+			NLRIEncoding::IP_MPLS(_) => None,
+		};
+	}
+}
+
+struct BytesCoder<'a>(&'a mut bytes::BytesMut);
+impl<'a> std::io::Write for BytesCoder<'a> {
+	fn write(&mut self, b: &[u8]) -> Result<usize, std::io::Error> {
+		self.0.extend_from_slice(&b);
+		Ok(b.len())
+	}
+	fn flush(&mut self) -> Result<(), std::io::Error> {
+		Ok(())
+	}
+}
+struct BytesDecoder<'a> {
+	buf: &'a mut bytes::BytesMut,
+	pos: usize,
+}
+impl<'a> std::io::Read for BytesDecoder<'a> {
+	fn read(&mut self, b: &mut [u8]) -> Result<usize, std::io::Error> {
+		let copy_len = cmp::min(b.len(), self.buf.len() - self.pos);
+		b[..copy_len].copy_from_slice(&self.buf[self.pos..self.pos + copy_len]);
+		self.pos += copy_len;
+		Ok(copy_len)
+	}
+}
+
+struct MsgCoder<'a>(&'a Printer);
+impl<'a> codec::Decoder for MsgCoder<'a> {
+	type Item = Message;
+	type Error = std::io::Error;
+
+	fn decode(&mut self, bytes: &mut bytes::BytesMut) -> Result<Option<Message>, std::io::Error> {
+		let mut decoder = BytesDecoder {
+			buf: bytes,
+			pos: 0
+		};
+		match (Reader {
+			stream: &mut decoder,
+			capabilities: Capabilities {
+				FOUR_OCTET_ASN_SUPPORT: true,
+				EXTENDED_PATH_NLRI_SUPPORT: true,
+			}
+		}).read() {
+			Ok((_header, msg)) => {
+				decoder.buf.advance(decoder.pos);
+				Ok(Some(msg))
+			},
+			Err(e) => match e.kind() {
+				std::io::ErrorKind::UnexpectedEof => Ok(None),
+				_ => Err(e),
+			},
+		}
+	}
+}
+impl<'a> codec::Encoder for MsgCoder<'a> {
+	type Item = Message;
+	type Error = std::io::Error;
+
+	fn encode(&mut self, msg: Message, res: &mut bytes::BytesMut) -> Result<(), std::io::Error> {
+		msg.write(&mut BytesCoder(res))?;
+		Ok(())
+	}
+}
+
+pub struct BGPClient {
+	routes: Mutex<RoutingTable>,
+	shutdown: AtomicBool,
+}
+impl BGPClient {
+	pub fn get_asn(&self, addr: IpAddr) -> u32 {
+		let attr_set = self.routes.lock().unwrap().get_route_attrs(addr);
+		let mut paths: Vec<(ASPath, u32, u32)> = Vec::new();
+		for attrs in attr_set.iter() {
+			let mut as4_path = None;
+			let mut as_path = None;
+			let mut pref = 100;
+			let mut med = 0;
+			for attr in attrs.iter() {
+				match attr {
+					PathAttribute::AS4_PATH(path) => as4_path = Some(path),
+					PathAttribute::AS_PATH(path) => as_path = Some(path),
+					PathAttribute::LOCAL_PREF(p) => pref = *p,
+					PathAttribute::MULTI_EXIT_DISC(m) => med = *m,
+					_ => {},
+				}
+			}
+			if let Some(path) = as4_path.or(as_path) {
+				paths.push((path.clone(), pref, med));
+			}
+		}
+		if paths.is_empty() { return 0; }
+
+		let mut path_vecs: Vec<_> = paths.iter_mut().map(|(p, pref, med)| {
+			let mut path = Vec::new();
+			for seg in p.segments.drain(..) {
+				match seg {
+					Segment::AS_SEQUENCE(mut asn) => path.append(&mut asn),
+					Segment::AS_SET(_) => {}, // Ignore sets for now, they're not that common anyway
+				}
+			}
+			(path, pref, med)
+		}).collect();
+		path_vecs.sort_unstable_by(|(path_a, pref_a, med_a), (path_b, pref_b, med_b)| {
+			pref_a.cmp(pref_b).then(path_b.len().cmp(&path_a.len())).then(med_b.cmp(med_a))
+		});
+		// TODO: Find last common ASN among all paths
+		*path_vecs[0].0.last().unwrap_or(&0)
+	}
+
+	pub fn disconnect(&self) {
+		self.shutdown.store(true, Ordering::Relaxed);
+	}
+
+	fn connect_given_client(addr: SocketAddr, timeout: Duration, printer: &'static Printer, client: Arc<BGPClient>) {
+		let connect_timeout = Delay::new(Instant::now() + timeout.clone()).then(|_| {
+			future::err(std::io::Error::new(std::io::ErrorKind::TimedOut, "timeout reached"))
+		});
+		let client_reconn = Arc::clone(&client);
+		tokio::spawn(TcpStream::connect(&addr).select(connect_timeout)
+			.or_else(move |_| {
+				Delay::new(Instant::now() + timeout / 10).then(|_| {
+					future::err(())
+				})
+			}).and_then(move |stream| {
+				let (write, read) = Framed::new(stream.0, MsgCoder(printer)).split();
+				let (mut sender, receiver) = mpsc::channel(10); // We never really should send more than 10 messages unless they're dumb
+				tokio::spawn(write.sink_map_err(|_| { () }).send_all(receiver)
+					.then(|_| {
+						future::err(())
+					}));
+				let _ = sender.try_send(Message::Open(Open {
+					version: 4,
+					peer_asn: 23456,
+					hold_timer: 120,
+					identifier: 0x453b1215, // 69.59.18.21
+					parameters: vec![OpenParameter::Capabilities(vec![
+						OpenCapability::MultiProtocol((AFI::IPV4, SAFI::Unicast)),
+						OpenCapability::MultiProtocol((AFI::IPV6, SAFI::Unicast)),
+						OpenCapability::FourByteASN(397444),
+						OpenCapability::RouteRefresh,
+						OpenCapability::AddPath(vec![
+							(AFI::IPV4, SAFI::Unicast, AddPathDirection::ReceivePaths),
+							(AFI::IPV6, SAFI::Unicast, AddPathDirection::ReceivePaths)]),
+					])]
+				}));
+				read.for_each(move |bgp_msg| {
+					if client.shutdown.load(Ordering::Relaxed) {
+						return future::err(std::io::Error::new(std::io::ErrorKind::Other, "Shutting Down"));
+					}
+					match bgp_msg {
+						Message::Open(_) => {
+							printer.add_line("Connected to BGP route provider".to_string(), true);
+						},
+						Message::KeepAlive => {
+							let _ = sender.try_send(Message::KeepAlive);
+						},
+						Message::Update(mut upd) => {
+							upd.normalize();
+							let mut route_table = client.routes.lock().unwrap();
+							for r in upd.withdrawn_routes {
+								route_table.withdraw(r);
+							}
+							let attrs = Arc::new(upd.attributes);
+							for r in upd.announced_routes {
+								route_table.announce(r, Arc::clone(&attrs));
+							}
+						},
+						_ => {}
+					}
+					future::ok(())
+				}).or_else(move |e| {
+					printer.add_line(format!("Got error from BGP stream: {:?}", e), true);
+					future::ok(())
+				})
+			}).then(move |_| {
+				if !client_reconn.shutdown.load(Ordering::Relaxed) {
+					BGPClient::connect_given_client(addr, timeout, printer, client_reconn);
+				}
+				future::ok(())
+			})
+		);
+	}
+
+	pub fn new(addr: SocketAddr, timeout: Duration, printer: &'static Printer) -> Arc<BGPClient> {
+		let client = Arc::new(BGPClient {
+			routes: Mutex::new(RoutingTable::new()),
+			shutdown: AtomicBool::new(false),
+		});
+		BGPClient::connect_given_client(addr, timeout, printer, Arc::clone(&client));
+		client
+	}
+}
diff --git a/src/datastore.rs b/src/datastore.rs
index 30d2c8e..c8ef0e0 100644
--- a/src/datastore.rs
+++ b/src/datastore.rs
@@ -16,6 +16,8 @@ use tokio::io::write_all;
 
 use regex::Regex;
 
+use crate::bgp_client::BGPClient;
+
 #[derive(Clone, Copy, Hash, PartialEq, Eq)]
 pub enum AddressState {
 	Untested,
@@ -437,7 +439,7 @@ impl Store {
 		settings_future.join(nodes_future).then(|_| { future::ok(()) })
 	}
 
-	pub fn write_dns(&'static self) -> impl Future<Item=(), Error=()> {
+	pub fn write_dns(&'static self, bgp_client: Arc<BGPClient>) -> impl Future<Item=(), Error=()> {
 		let dns_file = self.store.clone() + "/nodes.dump";
 		File::create(dns_file.clone() + ".tmp").and_then(move |f| {
 			let mut dns_buff = String::new();
@@ -496,10 +498,12 @@ impl Store {
 								.filter(|e| e.is_ipv6() && e.port() == 8333).map(|e| e.ip()).collect();
 						}
 					}
-					for a in v4_set.iter().choose_multiple(&mut rng, 21) {
+					let mut asn_set = HashSet::with_capacity(cmp::max(v4_set.len(), v6_set.len()));
+					for a in v4_set.iter().filter(|a| asn_set.insert(bgp_client.get_asn(**a))).choose_multiple(&mut rng, 21) {
 						dns_buff += &format!("x{:x}.dnsseed\tIN\tA\t{}\n", i, a);
 					}
-					for a in v6_set.iter().choose_multiple(&mut rng, 12) {
+					asn_set.clear();
+					for a in v6_set.iter().filter(|a| asn_set.insert(bgp_client.get_asn(**a))).choose_multiple(&mut rng, 12) {
 						dns_buff += &format!("x{:x}.dnsseed\tIN\tAAAA\t{}\n", i, a);
 					}
 				}
diff --git a/src/main.rs b/src/main.rs
index f72ba34..ba206d6 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,6 +1,7 @@
 mod printer;
 mod reader;
 mod peer;
+mod bgp_client;
 mod timeout_stream;
 mod datastore;
 
@@ -25,6 +26,7 @@ use peer::Peer;
 use datastore::{AddressState, Store, U64Setting, RegexSetting};
 use timeout_stream::TimeoutStream;
 use rand::Rng;
+use bgp_client::BGPClient;
 
 use tokio::prelude::*;
 use tokio::timer::Delay;
@@ -245,7 +247,7 @@ pub fn scan_node(scan_time: Instant, node: SocketAddr, manual: bool) {
 	}));
 }
 
-fn poll_dnsseeds() {
+fn poll_dnsseeds(bgp_client: Arc<BGPClient>) {
 	tokio::spawn(future::lazy(|| {
 		let printer = unsafe { PRINTER.as_ref().unwrap() };
 		let store = unsafe { DATA_STORE.as_ref().unwrap() };
@@ -258,10 +260,12 @@ fn poll_dnsseeds() {
 		printer.add_line(format!("Added {} new addresses from other DNS seeds", new_addrs), false);
 		Delay::new(Instant::now() + Duration::from_secs(60)).then(|_| {
 			let store = unsafe { DATA_STORE.as_ref().unwrap() };
-			let dns_future = store.write_dns();
+			let dns_future = store.write_dns(Arc::clone(&bgp_client));
 			store.save_data().join(dns_future).then(|_| {
 				if !START_SHUTDOWN.load(Ordering::Relaxed) {
-					poll_dnsseeds();
+					poll_dnsseeds(bgp_client);
+				} else {
+					bgp_client.disconnect();
 				}
 				future::ok(())
 			})
@@ -293,9 +297,10 @@ fn scan_net() {
 	}));
 }
 
-fn make_trusted_conn(trusted_sockaddr: SocketAddr) {
+fn make_trusted_conn(trusted_sockaddr: SocketAddr, bgp_client: Arc<BGPClient>) {
 	let printer = unsafe { PRINTER.as_ref().unwrap() };
 	let trusted_peer = Peer::new(trusted_sockaddr.clone(), Duration::from_secs(600), printer);
+	let bgp_reload = Arc::clone(&bgp_client);
 	tokio::spawn(trusted_peer.and_then(move |(mut trusted_write, trusted_read)| {
 		printer.add_line("Connected to local peer".to_string(), false);
 		let mut starting_height = 0;
@@ -378,7 +383,7 @@ fn make_trusted_conn(trusted_sockaddr: SocketAddr) {
 						*unsafe { REQUEST_BLOCK.as_ref().unwrap() }.lock().unwrap() = Arc::new((height, hash, block));
 						if !SCANNING.swap(true, Ordering::SeqCst) {
 							scan_net();
-							poll_dnsseeds();
+							poll_dnsseeds(Arc::clone(&bgp_client));
 						}
 					}
 				},
@@ -396,15 +401,15 @@ fn make_trusted_conn(trusted_sockaddr: SocketAddr) {
 	}).then(move |_: Result<(), ()>| {
 		if !START_SHUTDOWN.load(Ordering::Relaxed) {
 			printer.add_line("Lost connection from trusted peer".to_string(), true);
-			make_trusted_conn(trusted_sockaddr);
+			make_trusted_conn(trusted_sockaddr, bgp_reload);
 		}
 		future::ok(())
 	}));
 }
 
 fn main() {
-	if env::args().len() != 3 {
-		println!("USAGE: dnsseed-rust datastore localPeerAddress");
+	if env::args().len() != 4 {
+		println!("USAGE: dnsseed-rust datastore localPeerAddress bgp_peer");
 		return;
 	}
 
@@ -423,15 +428,16 @@ fn main() {
 		let mut args = env::args();
 		args.next();
 		let path = args.next().unwrap();
-		let addr = args.next().unwrap();
+		let trusted_sockaddr: SocketAddr = args.next().unwrap().parse().unwrap();
+		let bgp_sockaddr: SocketAddr = args.next().unwrap().parse().unwrap();
 
 		Store::new(path).and_then(move |store| {
 			unsafe { DATA_STORE = Some(Box::new(store)) };
 			let store = unsafe { DATA_STORE.as_ref().unwrap() };
 			unsafe { PRINTER = Some(Box::new(Printer::new(store))) };
 
-			let trusted_sockaddr: SocketAddr = addr.parse().unwrap();
-			make_trusted_conn(trusted_sockaddr);
+			let bgp_client = BGPClient::new(bgp_sockaddr, Duration::from_secs(600), unsafe { PRINTER.as_ref().unwrap() });
+			make_trusted_conn(trusted_sockaddr, bgp_client);
 
 			reader::read(store, unsafe { PRINTER.as_ref().unwrap() });