_ 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 = 2;
  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 = 32 - 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::new(),
  88                         v6_table: HashMap::new(),
  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 != $id);
 121                                                 if entry.get_mut().is_empty() {
 122                                                         entry.remove();
 123                                                 }
 124                                         },
 125                                         _ => {},
 126                                 }
 127                         } }
 128                 }
 129                 match route {
 130                         NLRIEncoding::IP(p) => {
 131                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
 132                                 match ip {
 133                                         IpAddr::V4(v4a) => remove!(self.v4_table, (v4a, len), 0),
 134                                         IpAddr::V6(v6a) => remove!(self.v6_table, (v6a, len), 0),
 135                                 }
 136                         },
 137                         NLRIEncoding::IP_WITH_PATH_ID((p, id)) => {
 138                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
 139                                 match ip {
 140                                         IpAddr::V4(v4a) => remove!(self.v4_table, (v4a, len), id),
 141                                         IpAddr::V6(v6a) => remove!(self.v6_table, (v6a, len), id),
 142                                 }
 143                         },
 144                         NLRIEncoding::IP_MPLS(_) => (),
 145                 };
 146         }
 147
 148         fn announce(&mut self, prefix: NLRIEncoding, route: Route) {
 149                 macro_rules! insert {
 150                         ($rt: expr, $v: expr, $id: expr) => { {
 151                                 let entry = $rt.entry($v.into()).or_insert(Vec::new());
 152                                 entry.retain(|e| e.0 != $id);
 153                                 entry.push(($id, route));
 154                         } }
 155                 }
 156                 match prefix {
 157                         NLRIEncoding::IP(p) => {
 158                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
 159                                 match ip {
 160                                         IpAddr::V4(v4a) => insert!(self.v4_table, (v4a, len), 0),
 161                                         IpAddr::V6(v6a) => insert!(self.v6_table, (v6a, len), 0),
 162                                 }
 163                         },
 164                         NLRIEncoding::IP_WITH_PATH_ID((p, id)) => {
 165                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
 166                                 match ip {
 167                                         IpAddr::V4(v4a) => insert!(self.v4_table, (v4a, len), id),
 168                                         IpAddr::V6(v6a) => insert!(self.v6_table, (v6a, len), id),
 169                                 }
 170                         },
 171                         NLRIEncoding::IP_MPLS(_) => (),
 172                 };
 173         }
 174 }
 175
 176 struct BytesCoder<'a>(&'a mut bytes::BytesMut);
 177 impl<'a> std::io::Write for BytesCoder<'a> {
 178         fn write(&mut self, b: &[u8]) -> Result<usize, std::io::Error> {
 179                 self.0.extend_from_slice(&b);
 180                 Ok(b.len())
 181         }
 182         fn flush(&mut self) -> Result<(), std::io::Error> {
 183                 Ok(())
 184         }
 185 }
 186 struct BytesDecoder<'a> {
 187         buf: &'a mut bytes::BytesMut,
 188         pos: usize,
 189 }
 190 impl<'a> std::io::Read for BytesDecoder<'a> {
 191         fn read(&mut self, b: &mut [u8]) -> Result<usize, std::io::Error> {
 192                 let copy_len = cmp::min(b.len(), self.buf.len() - self.pos);
 193                 b[..copy_len].copy_from_slice(&self.buf[self.pos..self.pos + copy_len]);
 194                 self.pos += copy_len;
 195                 Ok(copy_len)
 196         }
 197 }
 198
 199 struct MsgCoder<'a>(&'a Printer);
 200 impl<'a> codec::Decoder for MsgCoder<'a> {
 201         type Item = Message;
 202         type Error = std::io::Error;
 203
 204         fn decode(&mut self, bytes: &mut bytes::BytesMut) -> Result<Option<Message>, std::io::Error> {
 205                 let mut decoder = BytesDecoder {
 206                         buf: bytes,
 207                         pos: 0
 208                 };
 209                 match (Reader {
 210                         stream: &mut decoder,
 211                         capabilities: Capabilities {
 212                                 FOUR_OCTET_ASN_SUPPORT: true,
 213                                 EXTENDED_PATH_NLRI_SUPPORT: true,
 214                         }
 215                 }).read() {
 216                         Ok((_header, msg)) => {
 217                                 decoder.buf.advance(decoder.pos);
 218                                 Ok(Some(msg))
 219                         },
 220                         Err(e) => match e.kind() {
 221                                 std::io::ErrorKind::UnexpectedEof => Ok(None),
 222                                 _ => Err(e),
 223                         },
 224                 }
 225         }
 226 }
 227 impl<'a> codec::Encoder for MsgCoder<'a> {
 228         type Item = Message;
 229         type Error = std::io::Error;
 230
 231         fn encode(&mut self, msg: Message, res: &mut bytes::BytesMut) -> Result<(), std::io::Error> {
 232                 msg.write(&mut BytesCoder(res))?;
 233                 Ok(())
 234         }
 235 }
 236
 237 pub struct BGPClient {
 238         routes: Mutex<RoutingTable>,
 239         shutdown: AtomicBool,
 240 }
 241 impl BGPClient {
 242         pub fn get_asn(&self, addr: IpAddr) -> u32 {
 243                 let lock = self.routes.lock().unwrap();
 244                 let mut path_vecs = lock.get_route_attrs(addr).1;
 245                 if path_vecs.is_empty() { return 0; }
 246
 247                 path_vecs.sort_unstable_by(|path_a, path_b| {
 248                         path_a.pref.cmp(&path_b.pref)
 249                                 .then(path_b.path_len.cmp(&path_a.path_len))
 250                                 .then(path_b.med.cmp(&path_a.med))
 251                 });
 252
 253                 let primary_route = path_vecs.pop().unwrap();
 254                 'asn_candidates: for asn in primary_route.path_suffix.iter().rev() {
 255                         if *asn == 0 { continue 'asn_candidates; }
 256                         for secondary_route in path_vecs.iter() {
 257                                 if !secondary_route.path_suffix.contains(asn) {
 258                                         continue 'asn_candidates;
 259                                 }
 260                         }
 261                         return *asn;
 262                 }
 263
 264                 for asn in primary_route.path_suffix.iter().rev() {
 265                         if *asn != 0 {
 266                                 return *asn;
 267                         }
 268                 }
 269                 0
 270         }
 271
 272         pub fn get_path(&self, addr: IpAddr) -> (u8, [u32; PATH_SUFFIX_LEN]) {
 273                 let lock = self.routes.lock().unwrap();
 274                 let (prefixlen, mut path_vecs) = lock.get_route_attrs(addr);
 275                 if path_vecs.is_empty() { return (0, [0; PATH_SUFFIX_LEN]); }
 276
 277                 path_vecs.sort_unstable_by(|path_a, path_b| {
 278                         path_a.pref.cmp(&path_b.pref)
 279                                 .then(path_b.path_len.cmp(&path_a.path_len))
 280                                 .then(path_b.med.cmp(&path_a.med))
 281                 });
 282
 283                 let primary_route = path_vecs.pop().unwrap();
 284                 (prefixlen, primary_route.path_suffix)
 285         }
 286
 287         pub fn disconnect(&self) {
 288                 self.shutdown.store(true, Ordering::Relaxed);
 289         }
 290
 291         fn map_attrs(mut attrs: Vec<PathAttribute>) -> Option<Route> {
 292                 let mut as4_path = None;
 293                 let mut as_path = None;
 294                 let mut pref = 100;
 295                 let mut med = 0;
 296                 for attr in attrs.drain(..) {
 297                         match attr {
 298                                 PathAttribute::AS4_PATH(path) => as4_path = Some(path),
 299                                 PathAttribute::AS_PATH(path) => as_path = Some(path),
 300                                 PathAttribute::LOCAL_PREF(p) => pref = p,
 301                                 PathAttribute::MULTI_EXIT_DISC(m) => med = m,
 302                                 _ => {},
 303                         }
 304                 }
 305                 if let Some(mut aspath) = as4_path.or(as_path) {
 306                         let mut pathvec = Vec::new();
 307                         for seg in aspath.segments.drain(..) {
 308                                 match seg {
 309                                         Segment::AS_SEQUENCE(mut asn) => pathvec.append(&mut asn),
 310                                         Segment::AS_SET(_) => {}, // Ignore sets for now, they're not that common anyway
 311                                 }
 312                         }
 313                         let path_len = pathvec.len() as u32;
 314                         pathvec.dedup_by(|a, b| (*a).eq(b)); // Drop prepends, cause we don't care in this case
 315
 316                         let mut path_suffix = [0; PATH_SUFFIX_LEN];
 317                         for (idx, asn) in pathvec.iter().rev().enumerate() {
 318                                 path_suffix[PATH_SUFFIX_LEN - idx - 1] = *asn;
 319                                 if idx == PATH_SUFFIX_LEN - 1 { break; }
 320                         }
 321
 322                         return Some(Route {
 323                                 path_suffix,
 324                                 path_len,
 325                                 pref,
 326                                 med,
 327                         })
 328                 } else { None }
 329         }
 330
 331         fn connect_given_client(addr: SocketAddr, timeout: Duration, printer: &'static Printer, client: Arc<BGPClient>) {
 332                 tokio::spawn(Delay::new(Instant::now() + timeout / 4).then(move |_| {
 333                         let connect_timeout = Delay::new(Instant::now() + timeout.clone()).then(|_| {
 334                                 future::err(std::io::Error::new(std::io::ErrorKind::TimedOut, "timeout reached"))
 335                         });
 336                         let client_reconn = Arc::clone(&client);
 337                         TcpStream::connect(&addr).select(connect_timeout)
 338                                 .or_else(move |_| {
 339                                         Delay::new(Instant::now() + timeout / 2).then(|_| {
 340                                                 future::err(())
 341                                         })
 342                                 }).and_then(move |stream| {
 343                                         let (write, read) = Framed::new(stream.0, MsgCoder(printer)).split();
 344                                         let (mut sender, receiver) = mpsc::channel(10); // We never really should send more than 10 messages unless they're dumb
 345                                         tokio::spawn(write.sink_map_err(|_| { () }).send_all(receiver)
 346                                                 .then(|_| {
 347                                                         future::err(())
 348                                                 }));
 349                                         let _ = sender.try_send(Message::Open(Open {
 350                                                 version: 4,
 351                                                 peer_asn: 23456,
 352                                                 hold_timer: timeout.as_secs() as u16,
 353                                                 identifier: 0x453b1215, // 69.59.18.21
 354                                                 parameters: vec![OpenParameter::Capabilities(vec![
 355                                                         OpenCapability::MultiProtocol((AFI::IPV4, SAFI::Unicast)),
 356                                                         OpenCapability::MultiProtocol((AFI::IPV6, SAFI::Unicast)),
 357                                                         OpenCapability::FourByteASN(397444),
 358                                                         OpenCapability::RouteRefresh,
 359                                                         OpenCapability::AddPath(vec![
 360                                                                 (AFI::IPV4, SAFI::Unicast, AddPathDirection::ReceivePaths),
 361                                                                 (AFI::IPV6, SAFI::Unicast, AddPathDirection::ReceivePaths)]),
 362                                                 ])]
 363                                         }));
 364                                         TimeoutStream::new_persistent(read, timeout).for_each(move |bgp_msg| {
 365                                                 if client.shutdown.load(Ordering::Relaxed) {
 366                                                         return future::err(std::io::Error::new(std::io::ErrorKind::Other, "Shutting Down"));
 367                                                 }
 368                                                 match bgp_msg {
 369                                                         Message::Open(_) => {
 370                                                                 client.routes.lock().unwrap().v4_table.clear();
 371                                                                 client.routes.lock().unwrap().v6_table.clear();
 372                                                                 printer.add_line("Connected to BGP route provider".to_string(), false);
 373                                                         },
 374                                                         Message::KeepAlive => {
 375                                                                 let _ = sender.try_send(Message::KeepAlive);
 376                                                         },
 377                                                         Message::Update(mut upd) => {
 378                                                                 upd.normalize();
 379                                                                 let mut route_table = client.routes.lock().unwrap();
 380                                                                 for r in upd.withdrawn_routes {
 381                                                                         route_table.withdraw(r);
 382                                                                 }
 383                                                                 if let Some(path) = Self::map_attrs(upd.attributes) {
 384                                                                         for r in upd.announced_routes {
 385                                                                                 route_table.announce(r, path.clone());
 386                                                                         }
 387                                                                 }
 388                                                                 printer.set_stat(Stat::V4RoutingTableSize(route_table.v4_table.len()));
 389                                                                 printer.set_stat(Stat::V6RoutingTableSize(route_table.v6_table.len()));
 390                                                         },
 391                                                         _ => {}
 392                                                 }
 393                                                 future::ok(())
 394                                         }).or_else(move |e| {
 395                                                 printer.add_line(format!("Got error from BGP stream: {:?}", e), true);
 396                                                 future::ok(())
 397                                         })
 398                                 }).then(move |_| {
 399                                         if !client_reconn.shutdown.load(Ordering::Relaxed) {
 400                                                 BGPClient::connect_given_client(addr, timeout, printer, client_reconn);
 401                                         }
 402                                         future::ok(())
 403                                 })
 404                         })
 405                 );
 406         }
 407
 408         pub fn new(addr: SocketAddr, timeout: Duration, printer: &'static Printer) -> Arc<BGPClient> {
 409                 let client = Arc::new(BGPClient {
 410                         routes: Mutex::new(RoutingTable::new()),
 411                         shutdown: AtomicBool::new(false),
 412                 });
 413                 BGPClient::connect_given_client(addr, timeout, printer, Arc::clone(&client));
 414                 client
 415         }
 416 }