_ 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::prelude::*;
  15 use tokio::codec;
  16 use tokio::codec::Framed;
  17 use tokio::net::TcpStream;
  18 use tokio::timer::Delay;
  19
  20 use futures::sync::mpsc;
  21
  22 use crate::printer::{Printer, Stat};
  23 use crate::timeout_stream::TimeoutStream;
  24
  25 const PATH_SUFFIX_LEN: usize = 3;
  26 #[derive(Clone)]
  27 struct Route { // 32 bytes with a path id u32
  28         path_suffix: [u32; PATH_SUFFIX_LEN],
  29         path_len: u32,
  30         pref: u32,
  31         med: u32,
  32 }
  33 #[allow(dead_code)]
  34 const ROUTE_LEN: usize = 36 - std::mem::size_of::<(u32, Route)>();
  35
  36 // To keep memory tight (and since we dont' need such close alignment), newtype the v4/v6 routing
  37 // table entries to make sure they are aligned to single bytes.
  38
  39 #[repr(packed)]
  40 #[derive(PartialEq, Eq, Hash)]
  41 struct V4Addr {
  42         addr: [u8; 4],
  43         pfxlen: u8,
  44 }
  45 impl From<(Ipv4Addr, u8)> for V4Addr {
  46         fn from(p: (Ipv4Addr, u8)) -> Self {
  47                 Self {
  48                         addr: p.0.octets(),
  49                         pfxlen: p.1,
  50                 }
  51         }
  52 }
  53 #[allow(dead_code)]
  54 const V4_ALIGN: usize = 1 - std::mem::align_of::<V4Addr>();
  55 #[allow(dead_code)]
  56 const V4_SIZE: usize = 5 - std::mem::size_of::<V4Addr>();
  57
  58 #[repr(packed)]
  59 #[derive(PartialEq, Eq, Hash)]
  60 struct V6Addr {
  61         addr: [u8; 16],
  62         pfxlen: u8,
  63 }
  64 impl From<(Ipv6Addr, u8)> for V6Addr {
  65         fn from(p: (Ipv6Addr, u8)) -> Self {
  66                 Self {
  67                         addr: p.0.octets(),
  68                         pfxlen: p.1,
  69                 }
  70         }
  71 }
  72 #[allow(dead_code)]
  73 const V6_ALIGN: usize = 1 - std::mem::align_of::<V6Addr>();
  74 #[allow(dead_code)]
  75 const V6_SIZE: usize = 17 - std::mem::size_of::<V6Addr>();
  76
  77 struct RoutingTable {
  78         // We really want a HashMap for the values here, but they'll only ever contain a few entries,
  79         // and Vecs are way more memory-effecient in that case.
  80         v4_table: HashMap<V4Addr, Vec<(u32, Route)>>,
  81         v6_table: HashMap<V6Addr, Vec<(u32, Route)>>,
  82         max_paths: usize,
  83         routes_with_max: usize,
  84 }
  85
  86 impl RoutingTable {
  87         fn new() -> Self {
  88                 Self {
  89                         v4_table: HashMap::with_capacity(900_000),
  90                         v6_table: HashMap::with_capacity(100_000),
  91                         max_paths: 0,
  92                         routes_with_max: 0,
  93                 }
  94         }
  95
  96         fn get_route_attrs(&self, ip: IpAddr) -> (u8, Vec<&Route>) {
  97                 macro_rules! lookup_res {
  98                         ($addrty: ty, $addr: expr, $table: expr, $addr_bits: expr) => { {
  99                                 //TODO: Optimize this (probably means making the tables btrees)!
 100                                 let mut lookup = <$addrty>::from(($addr, $addr_bits));
 101                                 for i in 0..$addr_bits {
 102                                         if let Some(routes) = $table.get(&lookup) {
 103                                                 if routes.len() > 0 {
 104                                                         return (lookup.pfxlen, routes.iter().map(|v| &v.1).collect());
 105                                                 }
 106                                         }
 107                                         lookup.addr[lookup.addr.len() - (i/8) - 1] &= !(1u8 << (i % 8));
 108                                         lookup.pfxlen -= 1;
 109                                 }
 110                                 (0, vec![])
 111                         } }
 112                 }
 113                 match ip {
 114                         IpAddr::V4(v4a) => lookup_res!(V4Addr, v4a, self.v4_table, 32),
 115                         IpAddr::V6(v6a) => lookup_res!(V6Addr, v6a, self.v6_table, 128)
 116                 }
 117         }
 118
 119         fn withdraw(&mut self, route: NLRIEncoding) {
 120                 macro_rules! remove {
 121                         ($rt: expr, $v: expr, $id: expr) => { {
 122                                 match $rt.entry($v.into()) {
 123                                         hash_map::Entry::Occupied(mut entry) => {
 124                                                 if entry.get().len() == self.max_paths {
 125                                                         self.routes_with_max -= 1;
 126                                                         if self.routes_with_max == 0 {
 127                                                                 self.max_paths = 0;
 128                                                         }
 129                                                 }
 130                                                 entry.get_mut().retain(|e| e.0 != $id);
 131                                                 if entry.get_mut().is_empty() {
 132                                                         entry.remove();
 133                                                 }
 134                                         },
 135                                         _ => {},
 136                                 }
 137                         } }
 138                 }
 139                 match route {
 140                         NLRIEncoding::IP(p) => {
 141                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
 142                                 match ip {
 143                                         IpAddr::V4(v4a) => remove!(self.v4_table, (v4a, len), 0),
 144                                         IpAddr::V6(v6a) => remove!(self.v6_table, (v6a, len), 0),
 145                                 }
 146                         },
 147                         NLRIEncoding::IP_WITH_PATH_ID((p, id)) => {
 148                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
 149                                 match ip {
 150                                         IpAddr::V4(v4a) => remove!(self.v4_table, (v4a, len), id),
 151                                         IpAddr::V6(v6a) => remove!(self.v6_table, (v6a, len), id),
 152                                 }
 153                         },
 154                         NLRIEncoding::IP_MPLS(_) => (),
 155                         NLRIEncoding::IP_MPLS_WITH_PATH_ID(_) => (),
 156                         NLRIEncoding::IP_VPN_MPLS(_) => (),
 157                         NLRIEncoding::L2VPN(_) => (),
 158                 };
 159         }
 160
 161         fn announce(&mut self, prefix: NLRIEncoding, route: Route) {
 162                 macro_rules! insert {
 163                         ($rt: expr, $v: expr, $id: expr) => { {
 164                                 let old_max_paths = self.max_paths;
 165                                 let entry = $rt.entry($v.into()).or_insert_with(|| Vec::with_capacity(old_max_paths));
 166                                 let entry_had_max = entry.len() == self.max_paths;
 167                                 entry.retain(|e| e.0 != $id);
 168                                 if entry_had_max {
 169                                         entry.reserve_exact(1);
 170                                 } else {
 171                                         entry.reserve_exact(cmp::max(self.max_paths, entry.len() + 1) - entry.len());
 172                                 }
 173                                 entry.push(($id, route));
 174                                 if entry.len() > self.max_paths {
 175                                         self.max_paths = entry.len();
 176                                         self.routes_with_max = 1;
 177                                 } else if entry.len() == self.max_paths {
 178                                         if !entry_had_max { self.routes_with_max += 1; }
 179                                 }
 180                         } }
 181                 }
 182                 match prefix {
 183                         NLRIEncoding::IP(p) => {
 184                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
 185                                 match ip {
 186                                         IpAddr::V4(v4a) => insert!(self.v4_table, (v4a, len), 0),
 187                                         IpAddr::V6(v6a) => insert!(self.v6_table, (v6a, len), 0),
 188                                 }
 189                         },
 190                         NLRIEncoding::IP_WITH_PATH_ID((p, id)) => {
 191                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
 192                                 match ip {
 193                                         IpAddr::V4(v4a) => insert!(self.v4_table, (v4a, len), id),
 194                                         IpAddr::V6(v6a) => insert!(self.v6_table, (v6a, len), id),
 195                                 }
 196                         },
 197                         NLRIEncoding::IP_MPLS(_) => (),
 198                         NLRIEncoding::IP_MPLS_WITH_PATH_ID(_) => (),
 199                         NLRIEncoding::IP_VPN_MPLS(_) => (),
 200                         NLRIEncoding::L2VPN(_) => (),
 201                 };
 202         }
 203 }
 204
 205 struct BytesCoder<'a>(&'a mut bytes::BytesMut);
 206 impl<'a> std::io::Write for BytesCoder<'a> {
 207         fn write(&mut self, b: &[u8]) -> Result<usize, std::io::Error> {
 208                 self.0.extend_from_slice(&b);
 209                 Ok(b.len())
 210         }
 211         fn flush(&mut self) -> Result<(), std::io::Error> {
 212                 Ok(())
 213         }
 214 }
 215 struct BytesDecoder<'a> {
 216         buf: &'a mut bytes::BytesMut,
 217         pos: usize,
 218 }
 219 impl<'a> std::io::Read for BytesDecoder<'a> {
 220         fn read(&mut self, b: &mut [u8]) -> Result<usize, std::io::Error> {
 221                 let copy_len = cmp::min(b.len(), self.buf.len() - self.pos);
 222                 b[..copy_len].copy_from_slice(&self.buf[self.pos..self.pos + copy_len]);
 223                 self.pos += copy_len;
 224                 Ok(copy_len)
 225         }
 226 }
 227
 228 struct MsgCoder(Option<Capabilities>);
 229 impl codec::Decoder for MsgCoder {
 230         type Item = Message;
 231         type Error = std::io::Error;
 232
 233         fn decode(&mut self, bytes: &mut bytes::BytesMut) -> Result<Option<Message>, std::io::Error> {
 234                 let mut decoder = BytesDecoder {
 235                         buf: bytes,
 236                         pos: 0
 237                 };
 238                 let def_cap = Default::default();
 239                 let mut reader = Reader {
 240                         stream: &mut decoder,
 241                         capabilities: if let Some(cap) = &self.0 { cap } else { &def_cap },
 242                 };
 243                 match reader.read() {
 244                         Ok((_header, msg)) => {
 245                                 decoder.buf.advance(decoder.pos);
 246                                 if let Message::Open(ref o) = &msg {
 247                                         self.0 = Some(Capabilities::from_parameters(o.parameters.clone()));
 248                                 }
 249                                 Ok(Some(msg))
 250                         },
 251                         Err(e) => match e.kind() {
 252                                 std::io::ErrorKind::UnexpectedEof => Ok(None),
 253                                 _ => Err(e),
 254                         },
 255                 }
 256         }
 257 }
 258 impl codec::Encoder for MsgCoder {
 259         type Item = Message;
 260         type Error = std::io::Error;
 261
 262         fn encode(&mut self, msg: Message, res: &mut bytes::BytesMut) -> Result<(), std::io::Error> {
 263                 msg.encode(&mut BytesCoder(res))?;
 264                 Ok(())
 265         }
 266 }
 267
 268 pub struct BGPClient {
 269         routes: Mutex<RoutingTable>,
 270         shutdown: AtomicBool,
 271 }
 272 impl BGPClient {
 273         pub fn get_asn(&self, addr: IpAddr) -> u32 {
 274                 let lock = self.routes.lock().unwrap();
 275                 let mut path_vecs = lock.get_route_attrs(addr).1;
 276                 if path_vecs.is_empty() { return 0; }
 277
 278                 path_vecs.sort_unstable_by(|path_a, path_b| {
 279                         path_a.pref.cmp(&path_b.pref)
 280                                 .then(path_b.path_len.cmp(&path_a.path_len))
 281                                 .then(path_b.med.cmp(&path_a.med))
 282                 });
 283
 284                 let primary_route = path_vecs.pop().unwrap();
 285                 if path_vecs.len() > 3 {
 286                         // If we have at least 3 paths, try to find the last unique ASN which doesn't show up in other paths
 287                         // If we hit a T1 that is reasonably assumed to care about net neutrality, return the
 288                         // previous ASN.
 289                         let mut prev_asn = 0;
 290                         'asn_candidates: for asn in primary_route.path_suffix.iter().rev() {
 291                                 if *asn == 0 { continue 'asn_candidates; }
 292                                 match *asn {
 293                                         // Included: CenturyLink (L3), Cogent, Telia, NTT, GTT, Level3,
 294                                         //           GBLX (L3), Zayo, TI Sparkle Seabone, HE, Telefonica
 295                                         // Left out from Caida top-20: TATA, PCCW, Vodafone, RETN, Orange, Telstra,
 296                                         //                             Singtel, Rostelecom, DTAG
 297                                         209|174|1299|2914|3257|3356|3549|6461|6762|6939|12956 if prev_asn != 0 => return prev_asn,
 298                                         _ => if path_vecs.iter().any(|route| !route.path_suffix.contains(asn)) {
 299                                                 if prev_asn != 0 { return prev_asn } else {
 300                                                         // Multi-origin prefix, just give up and take the last AS in the
 301                                                         // default path
 302                                                         break 'asn_candidates;
 303                                                 }
 304                                         } else {
 305                                                 // We only ever possibly return an ASN if it appears in all paths
 306                                                 prev_asn = *asn;
 307                                         },
 308                                 }
 309                         }
 310                         // All paths were the same, if the first ASN is non-0, return it.
 311                         if prev_asn != 0 {
 312                                 return prev_asn;
 313                         }
 314                 }
 315
 316                 for asn in primary_route.path_suffix.iter().rev() {
 317                         if *asn != 0 {
 318                                 return *asn;
 319                         }
 320                 }
 321                 0
 322         }
 323
 324         pub fn get_path(&self, addr: IpAddr) -> (u8, [u32; PATH_SUFFIX_LEN]) {
 325                 let lock = self.routes.lock().unwrap();
 326                 let (prefixlen, mut path_vecs) = lock.get_route_attrs(addr);
 327                 if path_vecs.is_empty() { return (0, [0; PATH_SUFFIX_LEN]); }
 328
 329                 path_vecs.sort_unstable_by(|path_a, path_b| {
 330                         path_a.pref.cmp(&path_b.pref)
 331                                 .then(path_b.path_len.cmp(&path_a.path_len))
 332                                 .then(path_b.med.cmp(&path_a.med))
 333                 });
 334
 335                 let primary_route = path_vecs.pop().unwrap();
 336                 (prefixlen, primary_route.path_suffix)
 337         }
 338
 339         pub fn disconnect(&self) {
 340                 self.shutdown.store(true, Ordering::Relaxed);
 341         }
 342
 343         fn map_attrs(mut attrs: Vec<PathAttribute>) -> Option<Route> {
 344                 let mut as4_path = None;
 345                 let mut as_path = None;
 346                 let mut pref = 100;
 347                 let mut med = 0;
 348                 for attr in attrs.drain(..) {
 349                         match attr {
 350                                 PathAttribute::AS4_PATH(path) => as4_path = Some(path),
 351                                 PathAttribute::AS_PATH(path) => as_path = Some(path),
 352                                 PathAttribute::LOCAL_PREF(p) => pref = p,
 353                                 PathAttribute::MULTI_EXIT_DISC(m) => med = m,
 354                                 _ => {},
 355                         }
 356                 }
 357                 if let Some(mut aspath) = as4_path.or(as_path) {
 358                         let mut pathvec = Vec::new();
 359                         for seg in aspath.segments.drain(..) {
 360                                 match seg {
 361                                         Segment::AS_SEQUENCE(mut asn) => pathvec.append(&mut asn),
 362                                         Segment::AS_SET(_) => {}, // Ignore sets for now, they're not that common anyway
 363                                 }
 364                         }
 365                         let path_len = pathvec.len() as u32;
 366                         pathvec.dedup_by(|a, b| (*a).eq(b)); // Drop prepends, cause we don't care in this case
 367
 368                         let mut path_suffix = [0; PATH_SUFFIX_LEN];
 369                         for (idx, asn) in pathvec.iter().rev().enumerate() {
 370                                 path_suffix[PATH_SUFFIX_LEN - idx - 1] = *asn;
 371                                 if idx == PATH_SUFFIX_LEN - 1 { break; }
 372                         }
 373
 374                         return Some(Route {
 375                                 path_suffix,
 376                                 path_len,
 377                                 pref,
 378                                 med,
 379                         })
 380                 } else { None }
 381         }
 382
 383         fn connect_given_client(addr: SocketAddr, timeout: Duration, printer: &'static Printer, client: Arc<BGPClient>) {
 384                 tokio::spawn(Delay::new(Instant::now() + timeout / 4).then(move |_| {
 385                         let connect_timeout = Delay::new(Instant::now() + timeout.clone()).then(|_| {
 386                                 future::err(std::io::Error::new(std::io::ErrorKind::TimedOut, "timeout reached"))
 387                         });
 388                         let client_reconn = Arc::clone(&client);
 389                         TcpStream::connect(&addr).select(connect_timeout)
 390                                 .or_else(move |_| {
 391                                         Delay::new(Instant::now() + timeout / 2).then(|_| {
 392                                                 future::err(())
 393                                         })
 394                                 }).and_then(move |stream| {
 395                                         let (write, read) = Framed::new(stream.0, MsgCoder(None)).split();
 396                                         let (mut sender, receiver) = mpsc::channel(10); // We never really should send more than 10 messages unless they're dumb
 397                                         tokio::spawn(write.sink_map_err(|_| { () }).send_all(receiver)
 398                                                 .then(|_| {
 399                                                         future::err(())
 400                                                 }));
 401                                         let _ = sender.try_send(Message::Open(Open {
 402                                                 version: 4,
 403                                                 peer_asn: 23456,
 404                                                 hold_timer: timeout.as_secs() as u16,
 405                                                 identifier: 0x453b1215, // 69.59.18.21
 406                                                 parameters: vec![OpenParameter::Capabilities(vec![
 407                                                         OpenCapability::MultiProtocol((AFI::IPV4, SAFI::Unicast)),
 408                                                         OpenCapability::MultiProtocol((AFI::IPV6, SAFI::Unicast)),
 409                                                         OpenCapability::FourByteASN(397444),
 410                                                         OpenCapability::RouteRefresh,
 411                                                         OpenCapability::AddPath(vec![
 412                                                                 (AFI::IPV4, SAFI::Unicast, AddPathDirection::ReceivePaths),
 413                                                                 (AFI::IPV6, SAFI::Unicast, AddPathDirection::ReceivePaths)]),
 414                                                 ])],
 415                                         }));
 416                                         TimeoutStream::new_persistent(read, timeout).for_each(move |bgp_msg| {
 417                                                 if client.shutdown.load(Ordering::Relaxed) {
 418                                                         return future::err(std::io::Error::new(std::io::ErrorKind::Other, "Shutting Down"));
 419                                                 }
 420                                                 match bgp_msg {
 421                                                         Message::Open(_) => {
 422                                                                 client.routes.lock().unwrap().v4_table.clear();
 423                                                                 client.routes.lock().unwrap().v6_table.clear();
 424                                                                 printer.add_line("Connected to BGP route provider".to_string(), false);
 425                                                         },
 426                                                         Message::KeepAlive => {
 427                                                                 let _ = sender.try_send(Message::KeepAlive);
 428                                                         },
 429                                                         Message::Update(mut upd) => {
 430                                                                 upd.normalize();
 431                                                                 let mut route_table = client.routes.lock().unwrap();
 432                                                                 for r in upd.withdrawn_routes {
 433                                                                         route_table.withdraw(r);
 434                                                                 }
 435                                                                 if let Some(path) = Self::map_attrs(upd.attributes) {
 436                                                                         for r in upd.announced_routes {
 437                                                                                 route_table.announce(r, path.clone());
 438                                                                         }
 439                                                                 }
 440                                                                 printer.set_stat(Stat::V4RoutingTableSize(route_table.v4_table.len()));
 441                                                                 printer.set_stat(Stat::V6RoutingTableSize(route_table.v6_table.len()));
 442                                                                 printer.set_stat(Stat::RoutingTablePaths(route_table.max_paths));
 443                                                         },
 444                                                         _ => {}
 445                                                 }
 446                                                 future::ok(())
 447                                         }).or_else(move |e| {
 448                                                 printer.add_line(format!("Got error from BGP stream: {:?}", e), true);
 449                                                 future::ok(())
 450                                         })
 451                                 }).then(move |_| {
 452                                         if !client_reconn.shutdown.load(Ordering::Relaxed) {
 453                                                 BGPClient::connect_given_client(addr, timeout, printer, client_reconn);
 454                                         }
 455                                         future::ok(())
 456                                 })
 457                         })
 458                 );
 459         }
 460
 461         pub fn new(addr: SocketAddr, timeout: Duration, printer: &'static Printer) -> Arc<BGPClient> {
 462                 let client = Arc::new(BGPClient {
 463                         routes: Mutex::new(RoutingTable::new()),
 464                         shutdown: AtomicBool::new(false),
 465                 });
 466                 BGPClient::connect_given_client(addr, timeout, printer, Arc::clone(&client));
 467                 client
 468         }
 469 }