_ Git - dnsseed-rust/blob - src/bgp_client.rs

   1 use std::sync::{Arc, Mutex};
   2 use std::sync::atomic::{AtomicBool, Ordering};
   3 use std::cmp;
   4 use std::collections::{HashMap, hash_map};
   5 use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr};
   6 use std::time::{Duration, Instant};
   7
   8 use bgp_rs::{AFI, SAFI, AddPathDirection, Open, OpenCapability, OpenParameter, NLRIEncoding, PathAttribute};
   9 use bgp_rs::Capabilities;
  10 use bgp_rs::Segment;
  11 use bgp_rs::Message;
  12 use bgp_rs::Reader;
  13
  14 use tokio::net::TcpStream;
  15 use tokio::time;
  16
  17 use crate::printer::{Printer, Stat};
  18
  19 const PATH_SUFFIX_LEN: usize = 3;
  20 #[derive(Clone)]
  21 struct Route { // 32 bytes with a path id u32
  22         path_suffix: [u32; PATH_SUFFIX_LEN],
  23         path_len: u32,
  24         pref: u32,
  25         med: u32,
  26 }
  27 #[allow(dead_code)]
  28 const ROUTE_LEN: usize = 36 - std::mem::size_of::<(u32, Route)>();
  29
  30 // To keep memory tight (and since we dont' need such close alignment), newtype the v4/v6 routing
  31 // table entries to make sure they are aligned to single bytes.
  32
  33 #[repr(packed)]
  34 #[derive(PartialEq, Eq, Hash)]
  35 struct V4Addr {
  36         addr: [u8; 4],
  37         pfxlen: u8,
  38 }
  39 impl From<(Ipv4Addr, u8)> for V4Addr {
  40         fn from(p: (Ipv4Addr, u8)) -> Self {
  41                 Self {
  42                         addr: p.0.octets(),
  43                         pfxlen: p.1,
  44                 }
  45         }
  46 }
  47 #[allow(dead_code)]
  48 const V4_ALIGN: usize = 1 - std::mem::align_of::<V4Addr>();
  49 #[allow(dead_code)]
  50 const V4_SIZE: usize = 5 - std::mem::size_of::<V4Addr>();
  51
  52 #[repr(packed)]
  53 #[derive(PartialEq, Eq, Hash)]
  54 struct V6Addr {
  55         addr: [u8; 16],
  56         pfxlen: u8,
  57 }
  58 impl From<(Ipv6Addr, u8)> for V6Addr {
  59         fn from(p: (Ipv6Addr, u8)) -> Self {
  60                 Self {
  61                         addr: p.0.octets(),
  62                         pfxlen: p.1,
  63                 }
  64         }
  65 }
  66 #[allow(dead_code)]
  67 const V6_ALIGN: usize = 1 - std::mem::align_of::<V6Addr>();
  68 #[allow(dead_code)]
  69 const V6_SIZE: usize = 17 - std::mem::size_of::<V6Addr>();
  70
  71 struct RoutingTable {
  72         // We really want a HashMap for the values here, but they'll only ever contain a few entries,
  73         // and Vecs are way more memory-effecient in that case.
  74         v4_table: HashMap<V4Addr, Vec<(u32, Route)>>,
  75         v6_table: HashMap<V6Addr, Vec<(u32, Route)>>,
  76         max_paths: usize,
  77         routes_with_max: usize,
  78 }
  79
  80 impl RoutingTable {
  81         fn new() -> Self {
  82                 Self {
  83                         v4_table: HashMap::with_capacity(900_000),
  84                         v6_table: HashMap::with_capacity(100_000),
  85                         max_paths: 0,
  86                         routes_with_max: 0,
  87                 }
  88         }
  89
  90         fn get_route_attrs(&self, ip: IpAddr) -> (u8, Vec<&Route>) {
  91                 macro_rules! lookup_res {
  92                         ($addrty: ty, $addr: expr, $table: expr, $addr_bits: expr) => { {
  93                                 //TODO: Optimize this (probably means making the tables btrees)!
  94                                 let mut lookup = <$addrty>::from(($addr, $addr_bits));
  95                                 for i in 0..$addr_bits {
  96                                         if let Some(routes) = $table.get(&lookup) {
  97                                                 if routes.len() > 0 {
  98                                                         return (lookup.pfxlen, routes.iter().map(|v| &v.1).collect());
  99                                                 }
 100                                         }
 101                                         lookup.addr[lookup.addr.len() - (i/8) - 1] &= !(1u8 << (i % 8));
 102                                         lookup.pfxlen -= 1;
 103                                 }
 104                                 (0, vec![])
 105                         } }
 106                 }
 107                 match ip {
 108                         IpAddr::V4(v4a) => lookup_res!(V4Addr, v4a, self.v4_table, 32),
 109                         IpAddr::V6(v6a) => lookup_res!(V6Addr, v6a, self.v6_table, 128)
 110                 }
 111         }
 112
 113         fn withdraw(&mut self, route: NLRIEncoding) {
 114                 macro_rules! remove {
 115                         ($rt: expr, $v: expr, $id: expr) => { {
 116                                 match $rt.entry($v.into()) {
 117                                         hash_map::Entry::Occupied(mut entry) => {
 118                                                 if entry.get().len() == self.max_paths {
 119                                                         self.routes_with_max -= 1;
 120                                                         if self.routes_with_max == 0 {
 121                                                                 self.max_paths = 0;
 122                                                         }
 123                                                 }
 124                                                 entry.get_mut().retain(|e| e.0 != $id);
 125                                                 if entry.get_mut().is_empty() {
 126                                                         entry.remove();
 127                                                 }
 128                                         },
 129                                         _ => {},
 130                                 }
 131                         } }
 132                 }
 133                 match route {
 134                         NLRIEncoding::IP(p) => {
 135                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
 136                                 match ip {
 137                                         IpAddr::V4(v4a) => remove!(self.v4_table, (v4a, len), 0),
 138                                         IpAddr::V6(v6a) => remove!(self.v6_table, (v6a, len), 0),
 139                                 }
 140                         },
 141                         NLRIEncoding::IP_WITH_PATH_ID((p, id)) => {
 142                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
 143                                 match ip {
 144                                         IpAddr::V4(v4a) => remove!(self.v4_table, (v4a, len), id),
 145                                         IpAddr::V6(v6a) => remove!(self.v6_table, (v6a, len), id),
 146                                 }
 147                         },
 148                         NLRIEncoding::IP_MPLS(_) => (),
 149                         NLRIEncoding::IP_MPLS_WITH_PATH_ID(_) => (),
 150                         NLRIEncoding::IP_VPN_MPLS(_) => (),
 151                         NLRIEncoding::L2VPN(_) => (),
 152                 };
 153         }
 154
 155         fn announce(&mut self, prefix: NLRIEncoding, route: Route) {
 156                 macro_rules! insert {
 157                         ($rt: expr, $v: expr, $id: expr) => { {
 158                                 let old_max_paths = self.max_paths;
 159                                 let entry = $rt.entry($v.into()).or_insert_with(|| Vec::with_capacity(old_max_paths));
 160                                 let entry_had_max = entry.len() == self.max_paths;
 161                                 entry.retain(|e| e.0 != $id);
 162                                 if entry_had_max {
 163                                         entry.reserve_exact(1);
 164                                 } else {
 165                                         entry.reserve_exact(cmp::max(self.max_paths, entry.len() + 1) - entry.len());
 166                                 }
 167                                 entry.push(($id, route));
 168                                 if entry.len() > self.max_paths {
 169                                         self.max_paths = entry.len();
 170                                         self.routes_with_max = 1;
 171                                 } else if entry.len() == self.max_paths {
 172                                         if !entry_had_max { self.routes_with_max += 1; }
 173                                 }
 174                         } }
 175                 }
 176                 match prefix {
 177                         NLRIEncoding::IP(p) => {
 178                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
 179                                 match ip {
 180                                         IpAddr::V4(v4a) => insert!(self.v4_table, (v4a, len), 0),
 181                                         IpAddr::V6(v6a) => insert!(self.v6_table, (v6a, len), 0),
 182                                 }
 183                         },
 184                         NLRIEncoding::IP_WITH_PATH_ID((p, id)) => {
 185                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
 186                                 match ip {
 187                                         IpAddr::V4(v4a) => insert!(self.v4_table, (v4a, len), id),
 188                                         IpAddr::V6(v6a) => insert!(self.v6_table, (v6a, len), id),
 189                                 }
 190                         },
 191                         NLRIEncoding::IP_MPLS(_) => (),
 192                         NLRIEncoding::IP_MPLS_WITH_PATH_ID(_) => (),
 193                         NLRIEncoding::IP_VPN_MPLS(_) => (),
 194                         NLRIEncoding::L2VPN(_) => (),
 195                 };
 196         }
 197 }
 198
 199 /*struct BytesCoder<'a>(&'a mut bytes::BytesMut);
 200 impl<'a> std::io::Write for BytesCoder<'a> {
 201         fn write(&mut self, b: &[u8]) -> Result<usize, std::io::Error> {
 202                 self.0.extend_from_slice(&b);
 203                 Ok(b.len())
 204         }
 205         fn flush(&mut self) -> Result<(), std::io::Error> {
 206                 Ok(())
 207         }
 208 }
 209 struct BytesDecoder<'a> {
 210         buf: &'a mut bytes::BytesMut,
 211         pos: usize,
 212 }
 213 impl<'a> std::io::Read for BytesDecoder<'a> {
 214         fn read(&mut self, b: &mut [u8]) -> Result<usize, std::io::Error> {
 215                 let copy_len = cmp::min(b.len(), self.buf.len() - self.pos);
 216                 b[..copy_len].copy_from_slice(&self.buf[self.pos..self.pos + copy_len]);
 217                 self.pos += copy_len;
 218                 Ok(copy_len)
 219         }
 220 }
 221
 222 struct MsgCoder(Option<Capabilities>);
 223 impl codec::Decoder for MsgCoder {
 224         type Item = Message;
 225         type Error = std::io::Error;
 226
 227         fn decode(&mut self, bytes: &mut bytes::BytesMut) -> Result<Option<Message>, std::io::Error> {
 228                 let mut decoder = BytesDecoder {
 229                         buf: bytes,
 230                         pos: 0
 231                 };
 232                 let def_cap = Default::default();
 233                 let mut reader = Reader {
 234                         stream: &mut decoder,
 235                         capabilities: if let Some(cap) = &self.0 { cap } else { &def_cap },
 236                 };
 237                 match reader.read() {
 238                         Ok((_header, msg)) => {
 239                                 decoder.buf.advance(decoder.pos);
 240                                 if let Message::Open(ref o) = &msg {
 241                                 }
 242                                 Ok(Some(msg))
 243                         },
 244                         Err(e) => match e.kind() {
 245                                 std::io::ErrorKind::UnexpectedEof => Ok(None),
 246                                 _ => Err(e),
 247                         },
 248                 }
 249         }
 250 }
 251 impl codec::Encoder for MsgCoder {
 252         type Item = Message;
 253         type Error = std::io::Error;
 254
 255         fn encode(&mut self, msg: Message, res: &mut bytes::BytesMut) -> Result<(), std::io::Error> {
 256                 msg.encode(&mut BytesCoder(res))?;
 257                 Ok(())
 258         }
 259 }*/
 260
 261 pub struct BGPClient {
 262         routes: Mutex<RoutingTable>,
 263         shutdown: AtomicBool,
 264 }
 265 impl BGPClient {
 266         pub fn get_asn(&self, addr: IpAddr) -> u32 {
 267                 let lock = self.routes.lock().unwrap();
 268                 let mut path_vecs = lock.get_route_attrs(addr).1;
 269                 if path_vecs.is_empty() { return 0; }
 270
 271                 path_vecs.sort_unstable_by(|path_a, path_b| {
 272                         path_a.pref.cmp(&path_b.pref)
 273                                 .then(path_b.path_len.cmp(&path_a.path_len))
 274                                 .then(path_b.med.cmp(&path_a.med))
 275                 });
 276
 277                 let primary_route = path_vecs.pop().unwrap();
 278                 if path_vecs.len() > 3 {
 279                         // If we have at least 3 paths, try to find the last unique ASN which doesn't show up in other paths
 280                         // If we hit a T1 that is reasonably assumed to care about net neutrality, return the
 281                         // previous ASN.
 282                         let mut prev_asn = 0;
 283                         'asn_candidates: for asn in primary_route.path_suffix.iter().rev() {
 284                                 if *asn == 0 { continue 'asn_candidates; }
 285                                 match *asn {
 286                                         // Included: CenturyLink (L3), Cogent, Telia, NTT, GTT, Level3,
 287                                         //           GBLX (L3), Zayo, TI Sparkle Seabone, HE, Telefonica
 288                                         // Left out from Caida top-20: TATA, PCCW, Vodafone, RETN, Orange, Telstra,
 289                                         //                             Singtel, Rostelecom, DTAG
 290                                         209|174|1299|2914|3257|3356|3549|6461|6762|6939|12956 if prev_asn != 0 => return prev_asn,
 291                                         _ => if path_vecs.iter().any(|route| !route.path_suffix.contains(asn)) {
 292                                                 if prev_asn != 0 { return prev_asn } else {
 293                                                         // Multi-origin prefix, just give up and take the last AS in the
 294                                                         // default path
 295                                                         break 'asn_candidates;
 296                                                 }
 297                                         } else {
 298                                                 // We only ever possibly return an ASN if it appears in all paths
 299                                                 prev_asn = *asn;
 300                                         },
 301                                 }
 302                         }
 303                         // All paths were the same, if the first ASN is non-0, return it.
 304                         if prev_asn != 0 {
 305                                 return prev_asn;
 306                         }
 307                 }
 308
 309                 for asn in primary_route.path_suffix.iter().rev() {
 310                         if *asn != 0 {
 311                                 return *asn;
 312                         }
 313                 }
 314                 0
 315         }
 316
 317         pub fn get_path(&self, addr: IpAddr) -> (u8, [u32; PATH_SUFFIX_LEN]) {
 318                 let lock = self.routes.lock().unwrap();
 319                 let (prefixlen, mut path_vecs) = lock.get_route_attrs(addr);
 320                 if path_vecs.is_empty() { return (0, [0; PATH_SUFFIX_LEN]); }
 321
 322                 path_vecs.sort_unstable_by(|path_a, path_b| {
 323                         path_a.pref.cmp(&path_b.pref)
 324                                 .then(path_b.path_len.cmp(&path_a.path_len))
 325                                 .then(path_b.med.cmp(&path_a.med))
 326                 });
 327
 328                 let primary_route = path_vecs.pop().unwrap();
 329                 (prefixlen, primary_route.path_suffix)
 330         }
 331
 332         pub fn disconnect(&self) {
 333                 self.shutdown.store(true, Ordering::Relaxed);
 334         }
 335
 336         fn map_attrs(mut attrs: Vec<PathAttribute>) -> Option<Route> {
 337                 let mut as4_path = None;
 338                 let mut as_path = None;
 339                 let mut pref = 100;
 340                 let mut med = 0;
 341                 for attr in attrs.drain(..) {
 342                         match attr {
 343                                 PathAttribute::AS4_PATH(path) => as4_path = Some(path),
 344                                 PathAttribute::AS_PATH(path) => as_path = Some(path),
 345                                 PathAttribute::LOCAL_PREF(p) => pref = p,
 346                                 PathAttribute::MULTI_EXIT_DISC(m) => med = m,
 347                                 _ => {},
 348                         }
 349                 }
 350                 if let Some(mut aspath) = as4_path.or(as_path) {
 351                         let mut pathvec = Vec::new();
 352                         for seg in aspath.segments.drain(..) {
 353                                 match seg {
 354                                         Segment::AS_SEQUENCE(mut asn) => pathvec.append(&mut asn),
 355                                         Segment::AS_SET(_) => {}, // Ignore sets for now, they're not that common anyway
 356                                 }
 357                         }
 358                         let path_len = pathvec.len() as u32;
 359                         pathvec.dedup_by(|a, b| (*a).eq(b)); // Drop prepends, cause we don't care in this case
 360
 361                         let mut path_suffix = [0; PATH_SUFFIX_LEN];
 362                         for (idx, asn) in pathvec.iter().rev().enumerate() {
 363                                 path_suffix[PATH_SUFFIX_LEN - idx - 1] = *asn;
 364                                 if idx == PATH_SUFFIX_LEN - 1 { break; }
 365                         }
 366
 367                         return Some(Route {
 368                                 path_suffix,
 369                                 path_len,
 370                                 pref,
 371                                 med,
 372                         })
 373                 } else { None }
 374         }
 375
 376         async fn handle_peer(open_msg: Message, stream: TcpStream, timeout: Duration, printer: &'static Printer, client: Arc<BGPClient>) -> Result<(), std::io::Error> {
 377                 let mut open_bytes = [0; 64];
 378                         let len = {
 379                                 let mut write_cursor = std::io::Cursor::new(&mut open_bytes);
 380                                 open_msg.encode(&mut write_cursor);
 381                                 write_cursor.position()
 382                         };
 383                         stream.write_all(&open_bytes[..len]).await?;
 384                         let mut cap = Default::default();
 385
 386                         let mut readpending = Vec::new();
 387                         let mut readbuf = [0; 8192];
 388                         let mut msg_timeout = time::sleep(timeout);
 389                         'read_loop: loop {
 390                                 if client.shutdown.load(Ordering::Relaxed) {
 391                                         return std::io::Error::new(std::io::ErrorKind::Other, "Shutting Down");
 392                                 }
 393                                 tokio::select! {
 394                                         _ = msg_timeout => {
 395                                                 return Err(std::io::Error::new(std::io::ErrorKind::TimedOut, "Keepalive expired"));
 396                                         },
 397                                         res = stream.read(&mut readbuf) => {
 398                                                 let mut msg_opt = None;
 399                                                 let bytecnt = res?;
 400                                                 if readpending.is_empty() {
 401                                                         let mut cursor = std::io::Cursor::new(&readbuf[..bytecnt]);
 402                                                         let mut reader = Reader { stream: &mut cursor, capabilities: &cap };
 403                                                         match reader.read() {
 404                                                                 Ok((_header, newmsg)) => { readpending.append(&readbuf[cursor.position()..bytecnt]); newmsg = Some(msg_opt) },
 405                                                                 Err(e) if e.kind() == std::io::ErrorKind::UnexpectedEof => {
 406                                                                         readpending.append(&readbuf[..bytecnt]);
 407                                                                         continue 'read_loop;
 408                                                                 },
 409                                                                 Err(e) => return Err(e),
 410                                                         }
 411                                                 } else { readpending.append(&readbuf[..bytecnt]); }
 412                                                 loop {
 413                                                         if msg_opt.is_none() {
 414                                                                 let mut cursor = std::io::Cursor::new(&readpending);
 415                                                                 let mut reader = Reader { stream: &mut cursor, capabilities: &cap };
 416                                                                 match reader.read() {
 417                                                                         Ok((_header, newmsg)) => { newmsg = Some(msg_opt) },
 418                                                                         Err(e) if e.kind() == std::io::ErrorKind::UnexpectedEof => {},
 419                                                                         Err(e) => return Err(e),
 420                                                                 }
 421                                                                 readpending = readpending.split_off(cursor.position());
 422                                                         }
 423                                                         if let Some(bgp_msg) = msg_opt.take() {
 424                                                                 match bgp_msg {
 425                                                                         Message::Open(o) => {
 426                                                                                 cap = Capabilities::from_parameters(o.parameters.clone());
 427                                                                                 client.routes.lock().unwrap().v4_table.clear();
 428                                                                                 client.routes.lock().unwrap().v6_table.clear();
 429                                                                                 printer.add_line("Connected to BGP route provider".to_string(), false);
 430                                                                         },
 431                                                                         Message::KeepAlive => {
 432                                                                                 msg_timeout = time::sleep(timeout);
 433                                                                                 //XXX: let _ = sender.try_send(Message::KeepAlive);
 434                                                                         },
 435                                                                         Message::Update(mut upd) => {
 436                                                                                 upd.normalize();
 437                                                                                 let mut route_table = client.routes.lock().unwrap();
 438                                                                                 for r in upd.withdrawn_routes {
 439                                                                                         route_table.withdraw(r);
 440                                                                                 }
 441                                                                                 if let Some(path) = Self::map_attrs(upd.attributes) {
 442                                                                                         for r in upd.announced_routes {
 443                                                                                                 route_table.announce(r, path.clone());
 444                                                                                         }
 445                                                                                 }
 446                                                                                 printer.set_stat(Stat::V4RoutingTableSize(route_table.v4_table.len()));
 447                                                                                 printer.set_stat(Stat::V6RoutingTableSize(route_table.v6_table.len()));
 448                                                                                 printer.set_stat(Stat::RoutingTablePaths(route_table.max_paths));
 449                                                                         },
 450                                                                         _ => {}
 451                                                                 }
 452                                                         } else { break; }
 453                                                 }
 454                                         }
 455                                 };
 456                 }
 457         }
 458
 459         fn connect_given_client(remote_asn: u32, addr: SocketAddr, timeout: Duration, printer: &'static Printer, client: Arc<BGPClient>) {
 460                 tokio::spawn(async move {
 461                         time::sleep(timeout / 4).await;
 462
 463                         let client_reconn = Arc::clone(&client);
 464                         tokio::select! {
 465                                 _ = time::sleep(timeout) => {
 466                                         time::sleep(timeout / 2).await;
 467                                 },
 468                                 mut stream = TcpStream::connect(&addr) => {
 469                                         let peer_asn = if remote_asn > u16::max_value() as u32 { 23456 } else { remote_asn as u16 };
 470                                         let open_msg = Message::Open(Open {
 471                                                 version: 4,
 472                                                 peer_asn,
 473                                                 hold_timer: timeout.as_secs() as u16,
 474                                                 identifier: 0x453b1215, // 69.59.18.21. Note that you never actually need to change this.
 475                                                 parameters: vec![OpenParameter::Capabilities(vec![
 476                                                         OpenCapability::MultiProtocol((AFI::IPV4, SAFI::Unicast)),
 477                                                         OpenCapability::MultiProtocol((AFI::IPV6, SAFI::Unicast)),
 478                                                         OpenCapability::FourByteASN(remote_asn),
 479                                                         OpenCapability::RouteRefresh,
 480                                                         OpenCapability::AddPath(vec![
 481                                                                 (AFI::IPV4, SAFI::Unicast, AddPathDirection::ReceivePaths),
 482                                                                 (AFI::IPV6, SAFI::Unicast, AddPathDirection::ReceivePaths)]),
 483                                                 ])],
 484                                         });
 485                                         let e = Self::handle_peer(open_msg, stream, printer, client);
 486                                         printer.add_line(format!("Got error from BGP stream: {:?}", e), true);
 487                                 }
 488                         };
 489                         if !client_reconn.shutdown.load(Ordering::Relaxed) {
 490                                 BGPClient::connect_given_client(remote_asn, addr, timeout, printer, client_reconn);
 491                         }
 492                 });
 493         }
 494
 495         pub fn new(remote_asn: u32, addr: SocketAddr, timeout: Duration, printer: &'static Printer) -> Arc<BGPClient> {
 496                 let client = Arc::new(BGPClient {
 497                         routes: Mutex::new(RoutingTable::new()),
 498                         shutdown: AtomicBool::new(false),
 499                 });
 500                 BGPClient::connect_given_client(remote_asn, addr, timeout, printer, Arc::clone(&client));
 501                 client
 502         }
 503 }