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