_ 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;
   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
  28         path_suffix: [u32; PATH_SUFFIX_LEN],
  29         path_len: u32,
  30         pref: u32,
  31         med: u32,
  32 }
  33
  34 // To keep memory tight (and since we dont' need such close alignment), newtype the v4/v6 routing
  35 // table entries to make sure they are aligned to single bytes.
  36
  37 #[repr(packed)]
  38 #[derive(PartialEq, Eq, Hash)]
  39 struct V4Addr {
  40         addr: [u8; 4],
  41         pfxlen: u8,
  42 }
  43 impl From<(Ipv4Addr, u8)> for V4Addr {
  44         fn from(p: (Ipv4Addr, u8)) -> Self {
  45                 Self {
  46                         addr: p.0.octets(),
  47                         pfxlen: p.1,
  48                 }
  49         }
  50 }
  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
  67 struct RoutingTable {
  68         v4_table: HashMap<V4Addr, HashMap<u32, Route>>,
  69         v6_table: HashMap<V6Addr, HashMap<u32, Route>>,
  70 }
  71
  72 impl RoutingTable {
  73         fn new() -> Self {
  74                 Self {
  75                         v4_table: HashMap::new(),
  76                         v6_table: HashMap::new(),
  77                 }
  78         }
  79
  80         fn get_route_attrs(&self, ip: IpAddr) -> (u8, Vec<&Route>) {
  81                 macro_rules! lookup_res {
  82                         ($addrty: ty, $addr: expr, $table: expr, $addr_bits: expr) => { {
  83                                 //TODO: Optimize this (probably means making the tables btrees)!
  84                                 let mut lookup = <$addrty>::from(($addr, $addr_bits));
  85                                 for i in 0..$addr_bits {
  86                                         if let Some(routes) = $table.get(&lookup).map(|hm| hm.values()) {
  87                                                 if routes.len() > 0 {
  88                                                         return (lookup.pfxlen, routes.collect());
  89                                                 }
  90                                         }
  91                                         lookup.addr[lookup.addr.len() - (i/8) - 1] &= !(1u8 << (i % 8));
  92                                         lookup.pfxlen -= 1;
  93                                 }
  94                                 (0, vec![])
  95                         } }
  96                 }
  97                 match ip {
  98                         IpAddr::V4(v4a) => lookup_res!(V4Addr, v4a, self.v4_table, 32),
  99                         IpAddr::V6(v6a) => lookup_res!(V6Addr, v6a, self.v6_table, 128)
 100                 }
 101         }
 102
 103         fn withdraw(&mut self, route: NLRIEncoding) {
 104                 match route {
 105                         NLRIEncoding::IP(p) => {
 106                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
 107                                 match ip {
 108                                         IpAddr::V4(v4a) => self.v4_table.get_mut(&(v4a, len).into()).and_then(|hm| hm.remove(&0)),
 109                                         IpAddr::V6(v6a) => self.v6_table.get_mut(&(v6a, len).into()).and_then(|hm| hm.remove(&0)),
 110                                 }
 111                         },
 112                         NLRIEncoding::IP_WITH_PATH_ID((p, id)) => {
 113                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
 114                                 match ip {
 115                                         IpAddr::V4(v4a) => self.v4_table.get_mut(&(v4a, len).into()).and_then(|hm| hm.remove(&id)),
 116                                         IpAddr::V6(v6a) => self.v6_table.get_mut(&(v6a, len).into()).and_then(|hm| hm.remove(&id)),
 117                                 }
 118                         },
 119                         NLRIEncoding::IP_MPLS(_) => None,
 120                 };
 121         }
 122
 123         fn announce(&mut self, prefix: NLRIEncoding, route: Route) {
 124                 match prefix {
 125                         NLRIEncoding::IP(p) => {
 126                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
 127                                 match ip {
 128                                         IpAddr::V4(v4a) => self.v4_table.entry((v4a, len).into()).or_insert(HashMap::new()).insert(0, route),
 129                                         IpAddr::V6(v6a) => self.v6_table.entry((v6a, len).into()).or_insert(HashMap::new()).insert(0, route),
 130                                 }
 131                         },
 132                         NLRIEncoding::IP_WITH_PATH_ID((p, id)) => {
 133                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
 134                                 match ip {
 135                                         IpAddr::V4(v4a) => self.v4_table.entry((v4a, len).into()).or_insert(HashMap::new()).insert(id, route),
 136                                         IpAddr::V6(v6a) => self.v6_table.entry((v6a, len).into()).or_insert(HashMap::new()).insert(id, route),
 137                                 }
 138                         },
 139                         NLRIEncoding::IP_MPLS(_) => None,
 140                 };
 141         }
 142 }
 143
 144 struct BytesCoder<'a>(&'a mut bytes::BytesMut);
 145 impl<'a> std::io::Write for BytesCoder<'a> {
 146         fn write(&mut self, b: &[u8]) -> Result<usize, std::io::Error> {
 147                 self.0.extend_from_slice(&b);
 148                 Ok(b.len())
 149         }
 150         fn flush(&mut self) -> Result<(), std::io::Error> {
 151                 Ok(())
 152         }
 153 }
 154 struct BytesDecoder<'a> {
 155         buf: &'a mut bytes::BytesMut,
 156         pos: usize,
 157 }
 158 impl<'a> std::io::Read for BytesDecoder<'a> {
 159         fn read(&mut self, b: &mut [u8]) -> Result<usize, std::io::Error> {
 160                 let copy_len = cmp::min(b.len(), self.buf.len() - self.pos);
 161                 b[..copy_len].copy_from_slice(&self.buf[self.pos..self.pos + copy_len]);
 162                 self.pos += copy_len;
 163                 Ok(copy_len)
 164         }
 165 }
 166
 167 struct MsgCoder<'a>(&'a Printer);
 168 impl<'a> codec::Decoder for MsgCoder<'a> {
 169         type Item = Message;
 170         type Error = std::io::Error;
 171
 172         fn decode(&mut self, bytes: &mut bytes::BytesMut) -> Result<Option<Message>, std::io::Error> {
 173                 let mut decoder = BytesDecoder {
 174                         buf: bytes,
 175                         pos: 0
 176                 };
 177                 match (Reader {
 178                         stream: &mut decoder,
 179                         capabilities: Capabilities {
 180                                 FOUR_OCTET_ASN_SUPPORT: true,
 181                                 EXTENDED_PATH_NLRI_SUPPORT: true,
 182                         }
 183                 }).read() {
 184                         Ok((_header, msg)) => {
 185                                 decoder.buf.advance(decoder.pos);
 186                                 Ok(Some(msg))
 187                         },
 188                         Err(e) => match e.kind() {
 189                                 std::io::ErrorKind::UnexpectedEof => Ok(None),
 190                                 _ => Err(e),
 191                         },
 192                 }
 193         }
 194 }
 195 impl<'a> codec::Encoder for MsgCoder<'a> {
 196         type Item = Message;
 197         type Error = std::io::Error;
 198
 199         fn encode(&mut self, msg: Message, res: &mut bytes::BytesMut) -> Result<(), std::io::Error> {
 200                 msg.write(&mut BytesCoder(res))?;
 201                 Ok(())
 202         }
 203 }
 204
 205 pub struct BGPClient {
 206         routes: Mutex<RoutingTable>,
 207         shutdown: AtomicBool,
 208 }
 209 impl BGPClient {
 210         pub fn get_asn(&self, addr: IpAddr) -> u32 {
 211                 let lock = self.routes.lock().unwrap();
 212                 let mut path_vecs = lock.get_route_attrs(addr).1;
 213                 if path_vecs.is_empty() { return 0; }
 214
 215                 path_vecs.sort_unstable_by(|path_a, path_b| {
 216                         path_a.pref.cmp(&path_b.pref)
 217                                 .then(path_b.path_len.cmp(&path_a.path_len))
 218                                 .then(path_b.med.cmp(&path_a.med))
 219                 });
 220
 221                 let primary_route = path_vecs.pop().unwrap();
 222                 'asn_candidates: for asn in primary_route.path_suffix.iter().rev() {
 223                         if *asn == 0 { continue 'asn_candidates; }
 224                         for secondary_route in path_vecs.iter() {
 225                                 if !secondary_route.path_suffix.contains(asn) {
 226                                         continue 'asn_candidates;
 227                                 }
 228                         }
 229                         return *asn;
 230                 }
 231
 232                 for asn in primary_route.path_suffix.iter().rev() {
 233                         if *asn != 0 {
 234                                 return *asn;
 235                         }
 236                 }
 237                 0
 238         }
 239
 240         pub fn get_path(&self, addr: IpAddr) -> (u8, [u32; PATH_SUFFIX_LEN]) {
 241                 let lock = self.routes.lock().unwrap();
 242                 let (prefixlen, mut path_vecs) = lock.get_route_attrs(addr);
 243                 if path_vecs.is_empty() { return (0, [0; PATH_SUFFIX_LEN]); }
 244
 245                 path_vecs.sort_unstable_by(|path_a, path_b| {
 246                         path_a.pref.cmp(&path_b.pref)
 247                                 .then(path_b.path_len.cmp(&path_a.path_len))
 248                                 .then(path_b.med.cmp(&path_a.med))
 249                 });
 250
 251                 let primary_route = path_vecs.pop().unwrap();
 252                 (prefixlen, primary_route.path_suffix)
 253         }
 254
 255         pub fn disconnect(&self) {
 256                 self.shutdown.store(true, Ordering::Relaxed);
 257         }
 258
 259         fn map_attrs(mut attrs: Vec<PathAttribute>) -> Option<Route> {
 260                 let mut as4_path = None;
 261                 let mut as_path = None;
 262                 let mut pref = 100;
 263                 let mut med = 0;
 264                 for attr in attrs.drain(..) {
 265                         match attr {
 266                                 PathAttribute::AS4_PATH(path) => as4_path = Some(path),
 267                                 PathAttribute::AS_PATH(path) => as_path = Some(path),
 268                                 PathAttribute::LOCAL_PREF(p) => pref = p,
 269                                 PathAttribute::MULTI_EXIT_DISC(m) => med = m,
 270                                 _ => {},
 271                         }
 272                 }
 273                 if let Some(mut aspath) = as4_path.or(as_path) {
 274                         let mut pathvec = Vec::new();
 275                         for seg in aspath.segments.drain(..) {
 276                                 match seg {
 277                                         Segment::AS_SEQUENCE(mut asn) => pathvec.append(&mut asn),
 278                                         Segment::AS_SET(_) => {}, // Ignore sets for now, they're not that common anyway
 279                                 }
 280                         }
 281                         let path_len = pathvec.len() as u32;
 282                         pathvec.dedup_by(|a, b| (*a).eq(b)); // Drop prepends, cause we don't care in this case
 283
 284                         let mut path_suffix = [0; PATH_SUFFIX_LEN];
 285                         for (idx, asn) in pathvec.iter().rev().enumerate() {
 286                                 path_suffix[PATH_SUFFIX_LEN - idx - 1] = *asn;
 287                                 if idx == PATH_SUFFIX_LEN - 1 { break; }
 288                         }
 289
 290                         return Some(Route {
 291                                 path_suffix,
 292                                 path_len,
 293                                 pref,
 294                                 med,
 295                         })
 296                 } else { None }
 297         }
 298
 299         fn connect_given_client(addr: SocketAddr, timeout: Duration, printer: &'static Printer, client: Arc<BGPClient>) {
 300                 tokio::spawn(Delay::new(Instant::now() + timeout / 4).then(move |_| {
 301                         let connect_timeout = Delay::new(Instant::now() + timeout.clone()).then(|_| {
 302                                 future::err(std::io::Error::new(std::io::ErrorKind::TimedOut, "timeout reached"))
 303                         });
 304                         let client_reconn = Arc::clone(&client);
 305                         TcpStream::connect(&addr).select(connect_timeout)
 306                                 .or_else(move |_| {
 307                                         Delay::new(Instant::now() + timeout / 2).then(|_| {
 308                                                 future::err(())
 309                                         })
 310                                 }).and_then(move |stream| {
 311                                         let (write, read) = Framed::new(stream.0, MsgCoder(printer)).split();
 312                                         let (mut sender, receiver) = mpsc::channel(10); // We never really should send more than 10 messages unless they're dumb
 313                                         tokio::spawn(write.sink_map_err(|_| { () }).send_all(receiver)
 314                                                 .then(|_| {
 315                                                         future::err(())
 316                                                 }));
 317                                         let _ = sender.try_send(Message::Open(Open {
 318                                                 version: 4,
 319                                                 peer_asn: 23456,
 320                                                 hold_timer: timeout.as_secs() as u16,
 321                                                 identifier: 0x453b1215, // 69.59.18.21
 322                                                 parameters: vec![OpenParameter::Capabilities(vec![
 323                                                         OpenCapability::MultiProtocol((AFI::IPV4, SAFI::Unicast)),
 324                                                         OpenCapability::MultiProtocol((AFI::IPV6, SAFI::Unicast)),
 325                                                         OpenCapability::FourByteASN(397444),
 326                                                         OpenCapability::RouteRefresh,
 327                                                         OpenCapability::AddPath(vec![
 328                                                                 (AFI::IPV4, SAFI::Unicast, AddPathDirection::ReceivePaths),
 329                                                                 (AFI::IPV6, SAFI::Unicast, AddPathDirection::ReceivePaths)]),
 330                                                 ])]
 331                                         }));
 332                                         TimeoutStream::new_persistent(read, timeout).for_each(move |bgp_msg| {
 333                                                 if client.shutdown.load(Ordering::Relaxed) {
 334                                                         return future::err(std::io::Error::new(std::io::ErrorKind::Other, "Shutting Down"));
 335                                                 }
 336                                                 match bgp_msg {
 337                                                         Message::Open(_) => {
 338                                                                 client.routes.lock().unwrap().v4_table.clear();
 339                                                                 client.routes.lock().unwrap().v6_table.clear();
 340                                                                 printer.add_line("Connected to BGP route provider".to_string(), false);
 341                                                         },
 342                                                         Message::KeepAlive => {
 343                                                                 let _ = sender.try_send(Message::KeepAlive);
 344                                                         },
 345                                                         Message::Update(mut upd) => {
 346                                                                 upd.normalize();
 347                                                                 let mut route_table = client.routes.lock().unwrap();
 348                                                                 for r in upd.withdrawn_routes {
 349                                                                         route_table.withdraw(r);
 350                                                                 }
 351                                                                 if let Some(path) = Self::map_attrs(upd.attributes) {
 352                                                                         for r in upd.announced_routes {
 353                                                                                 route_table.announce(r, path.clone());
 354                                                                         }
 355                                                                 }
 356                                                                 printer.set_stat(Stat::V4RoutingTableSize(route_table.v4_table.len()));
 357                                                                 printer.set_stat(Stat::V6RoutingTableSize(route_table.v6_table.len()));
 358                                                         },
 359                                                         _ => {}
 360                                                 }
 361                                                 future::ok(())
 362                                         }).or_else(move |e| {
 363                                                 printer.add_line(format!("Got error from BGP stream: {:?}", e), true);
 364                                                 future::ok(())
 365                                         })
 366                                 }).then(move |_| {
 367                                         if !client_reconn.shutdown.load(Ordering::Relaxed) {
 368                                                 BGPClient::connect_given_client(addr, timeout, printer, client_reconn);
 369                                         }
 370                                         future::ok(())
 371                                 })
 372                         })
 373                 );
 374         }
 375
 376         pub fn new(addr: SocketAddr, timeout: Duration, printer: &'static Printer) -> Arc<BGPClient> {
 377                 let client = Arc::new(BGPClient {
 378                         routes: Mutex::new(RoutingTable::new()),
 379                         shutdown: AtomicBool::new(false),
 380                 });
 381                 BGPClient::connect_given_client(addr, timeout, printer, Arc::clone(&client));
 382                 client
 383         }
 384 }