_ 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 struct RoutingTable {
  35         v4_table: HashMap<(Ipv4Addr, u8), HashMap<u32, Route>>,
  36         v6_table: HashMap<(Ipv6Addr, u8), HashMap<u32, Route>>,
  37 }
  38
  39 impl RoutingTable {
  40         fn new() -> Self {
  41                 Self {
  42                         v4_table: HashMap::new(),
  43                         v6_table: HashMap::new(),
  44                 }
  45         }
  46
  47         fn get_route_attrs(&self, ip: IpAddr) -> (u8, Vec<&Route>) {
  48                 macro_rules! lookup_res {
  49                         ($addrty: ty, $addr: expr, $table: expr, $addr_bits: expr) => { {
  50                                 //TODO: Optimize this (probably means making the tables btrees)!
  51                                 for i in (0..$addr_bits).rev() {
  52                                         let mut lookup = $addr.octets();
  53                                         for b in 0..(i / 8) {
  54                                                 lookup[lookup.len() - b - 1] = 0;
  55                                         }
  56                                         lookup[lookup.len() - (i/8) - 1] &= !(((1u16 << (i % 8)) - 1) as u8);
  57                                         let lookup_addr = <$addrty>::from(lookup);
  58                                         if let Some(routes) = $table.get(&(lookup_addr, $addr_bits - i as u8)).map(|hm| hm.values()) {
  59                                                 if routes.len() > 0 {
  60                                                         return ($addr_bits - i as u8, routes.collect());
  61                                                 }
  62                                         }
  63                                 }
  64                                 (0, vec![])
  65                         } }
  66                 }
  67                 match ip {
  68                         IpAddr::V4(v4a) => lookup_res!(Ipv4Addr, v4a, self.v4_table, 32),
  69                         IpAddr::V6(v6a) => lookup_res!(Ipv6Addr, v6a, self.v6_table, 128)
  70                 }
  71         }
  72
  73         fn withdraw(&mut self, route: NLRIEncoding) {
  74                 match route {
  75                         NLRIEncoding::IP(p) => {
  76                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
  77                                 match ip {
  78                                         IpAddr::V4(v4a) => self.v4_table.get_mut(&(v4a, len)).and_then(|hm| hm.remove(&0)),
  79                                         IpAddr::V6(v6a) => self.v6_table.get_mut(&(v6a, len)).and_then(|hm| hm.remove(&0)),
  80                                 }
  81                         },
  82                         NLRIEncoding::IP_WITH_PATH_ID((p, id)) => {
  83                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
  84                                 match ip {
  85                                         IpAddr::V4(v4a) => self.v4_table.get_mut(&(v4a, len)).and_then(|hm| hm.remove(&id)),
  86                                         IpAddr::V6(v6a) => self.v6_table.get_mut(&(v6a, len)).and_then(|hm| hm.remove(&id)),
  87                                 }
  88                         },
  89                         NLRIEncoding::IP_MPLS(_) => None,
  90                 };
  91         }
  92
  93         fn announce(&mut self, prefix: NLRIEncoding, route: Route) {
  94                 match prefix {
  95                         NLRIEncoding::IP(p) => {
  96                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
  97                                 match ip {
  98                                         IpAddr::V4(v4a) => self.v4_table.entry((v4a, len)).or_insert(HashMap::new()).insert(0, route),
  99                                         IpAddr::V6(v6a) => self.v6_table.entry((v6a, len)).or_insert(HashMap::new()).insert(0, route),
 100                                 }
 101                         },
 102                         NLRIEncoding::IP_WITH_PATH_ID((p, id)) => {
 103                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
 104                                 match ip {
 105                                         IpAddr::V4(v4a) => self.v4_table.entry((v4a, len)).or_insert(HashMap::new()).insert(id, route),
 106                                         IpAddr::V6(v6a) => self.v6_table.entry((v6a, len)).or_insert(HashMap::new()).insert(id, route),
 107                                 }
 108                         },
 109                         NLRIEncoding::IP_MPLS(_) => None,
 110                 };
 111         }
 112 }
 113
 114 struct BytesCoder<'a>(&'a mut bytes::BytesMut);
 115 impl<'a> std::io::Write for BytesCoder<'a> {
 116         fn write(&mut self, b: &[u8]) -> Result<usize, std::io::Error> {
 117                 self.0.extend_from_slice(&b);
 118                 Ok(b.len())
 119         }
 120         fn flush(&mut self) -> Result<(), std::io::Error> {
 121                 Ok(())
 122         }
 123 }
 124 struct BytesDecoder<'a> {
 125         buf: &'a mut bytes::BytesMut,
 126         pos: usize,
 127 }
 128 impl<'a> std::io::Read for BytesDecoder<'a> {
 129         fn read(&mut self, b: &mut [u8]) -> Result<usize, std::io::Error> {
 130                 let copy_len = cmp::min(b.len(), self.buf.len() - self.pos);
 131                 b[..copy_len].copy_from_slice(&self.buf[self.pos..self.pos + copy_len]);
 132                 self.pos += copy_len;
 133                 Ok(copy_len)
 134         }
 135 }
 136
 137 struct MsgCoder<'a>(&'a Printer);
 138 impl<'a> codec::Decoder for MsgCoder<'a> {
 139         type Item = Message;
 140         type Error = std::io::Error;
 141
 142         fn decode(&mut self, bytes: &mut bytes::BytesMut) -> Result<Option<Message>, std::io::Error> {
 143                 let mut decoder = BytesDecoder {
 144                         buf: bytes,
 145                         pos: 0
 146                 };
 147                 match (Reader {
 148                         stream: &mut decoder,
 149                         capabilities: Capabilities {
 150                                 FOUR_OCTET_ASN_SUPPORT: true,
 151                                 EXTENDED_PATH_NLRI_SUPPORT: true,
 152                         }
 153                 }).read() {
 154                         Ok((_header, msg)) => {
 155                                 decoder.buf.advance(decoder.pos);
 156                                 Ok(Some(msg))
 157                         },
 158                         Err(e) => match e.kind() {
 159                                 std::io::ErrorKind::UnexpectedEof => Ok(None),
 160                                 _ => Err(e),
 161                         },
 162                 }
 163         }
 164 }
 165 impl<'a> codec::Encoder for MsgCoder<'a> {
 166         type Item = Message;
 167         type Error = std::io::Error;
 168
 169         fn encode(&mut self, msg: Message, res: &mut bytes::BytesMut) -> Result<(), std::io::Error> {
 170                 msg.write(&mut BytesCoder(res))?;
 171                 Ok(())
 172         }
 173 }
 174
 175 pub struct BGPClient {
 176         routes: Mutex<RoutingTable>,
 177         shutdown: AtomicBool,
 178 }
 179 impl BGPClient {
 180         pub fn get_asn(&self, addr: IpAddr) -> u32 {
 181                 let lock = self.routes.lock().unwrap();
 182                 let mut path_vecs = lock.get_route_attrs(addr).1;
 183                 if path_vecs.is_empty() { return 0; }
 184
 185                 path_vecs.sort_unstable_by(|path_a, path_b| {
 186                         path_a.pref.cmp(&path_b.pref)
 187                                 .then(path_b.path_len.cmp(&path_a.path_len))
 188                                 .then(path_b.med.cmp(&path_a.med))
 189                 });
 190
 191                 let primary_route = path_vecs.pop().unwrap();
 192                 'asn_candidates: for asn in primary_route.path_suffix.iter().rev() {
 193                         if *asn == 0 { continue 'asn_candidates; }
 194                         for secondary_route in path_vecs.iter() {
 195                                 if !secondary_route.path_suffix.contains(asn) {
 196                                         continue 'asn_candidates;
 197                                 }
 198                         }
 199                         return *asn;
 200                 }
 201
 202                 for asn in primary_route.path_suffix.iter().rev() {
 203                         if *asn != 0 {
 204                                 return *asn;
 205                         }
 206                 }
 207                 0
 208         }
 209
 210         pub fn get_path(&self, addr: IpAddr) -> (u8, [u32; PATH_SUFFIX_LEN]) {
 211                 let lock = self.routes.lock().unwrap();
 212                 let (prefixlen, mut path_vecs) = lock.get_route_attrs(addr);
 213                 if path_vecs.is_empty() { return (0, [0; PATH_SUFFIX_LEN]); }
 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                 (prefixlen, primary_route.path_suffix)
 223         }
 224
 225         pub fn disconnect(&self) {
 226                 self.shutdown.store(true, Ordering::Relaxed);
 227         }
 228
 229         fn map_attrs(mut attrs: Vec<PathAttribute>) -> Option<Route> {
 230                 let mut as4_path = None;
 231                 let mut as_path = None;
 232                 let mut pref = 100;
 233                 let mut med = 0;
 234                 for attr in attrs.drain(..) {
 235                         match attr {
 236                                 PathAttribute::AS4_PATH(path) => as4_path = Some(path),
 237                                 PathAttribute::AS_PATH(path) => as_path = Some(path),
 238                                 PathAttribute::LOCAL_PREF(p) => pref = p,
 239                                 PathAttribute::MULTI_EXIT_DISC(m) => med = m,
 240                                 _ => {},
 241                         }
 242                 }
 243                 if let Some(mut aspath) = as4_path.or(as_path) {
 244                         let mut pathvec = Vec::new();
 245                         for seg in aspath.segments.drain(..) {
 246                                 match seg {
 247                                         Segment::AS_SEQUENCE(mut asn) => pathvec.append(&mut asn),
 248                                         Segment::AS_SET(_) => {}, // Ignore sets for now, they're not that common anyway
 249                                 }
 250                         }
 251                         let path_len = pathvec.len() as u32;
 252                         pathvec.dedup_by(|a, b| (*a).eq(b)); // Drop prepends, cause we don't care in this case
 253
 254                         let mut path_suffix = [0; PATH_SUFFIX_LEN];
 255                         for (idx, asn) in pathvec.iter().rev().enumerate() {
 256                                 path_suffix[PATH_SUFFIX_LEN - idx - 1] = *asn;
 257                                 if idx == PATH_SUFFIX_LEN - 1 { break; }
 258                         }
 259
 260                         return Some(Route {
 261                                 path_suffix,
 262                                 path_len,
 263                                 pref,
 264                                 med,
 265                         })
 266                 } else { None }
 267         }
 268
 269         fn connect_given_client(addr: SocketAddr, timeout: Duration, printer: &'static Printer, client: Arc<BGPClient>) {
 270                 tokio::spawn(Delay::new(Instant::now() + timeout / 4).then(move |_| {
 271                         let connect_timeout = Delay::new(Instant::now() + timeout.clone()).then(|_| {
 272                                 future::err(std::io::Error::new(std::io::ErrorKind::TimedOut, "timeout reached"))
 273                         });
 274                         let client_reconn = Arc::clone(&client);
 275                         TcpStream::connect(&addr).select(connect_timeout)
 276                                 .or_else(move |_| {
 277                                         Delay::new(Instant::now() + timeout / 2).then(|_| {
 278                                                 future::err(())
 279                                         })
 280                                 }).and_then(move |stream| {
 281                                         let (write, read) = Framed::new(stream.0, MsgCoder(printer)).split();
 282                                         let (mut sender, receiver) = mpsc::channel(10); // We never really should send more than 10 messages unless they're dumb
 283                                         tokio::spawn(write.sink_map_err(|_| { () }).send_all(receiver)
 284                                                 .then(|_| {
 285                                                         future::err(())
 286                                                 }));
 287                                         let _ = sender.try_send(Message::Open(Open {
 288                                                 version: 4,
 289                                                 peer_asn: 23456,
 290                                                 hold_timer: timeout.as_secs() as u16,
 291                                                 identifier: 0x453b1215, // 69.59.18.21
 292                                                 parameters: vec![OpenParameter::Capabilities(vec![
 293                                                         OpenCapability::MultiProtocol((AFI::IPV4, SAFI::Unicast)),
 294                                                         OpenCapability::MultiProtocol((AFI::IPV6, SAFI::Unicast)),
 295                                                         OpenCapability::FourByteASN(397444),
 296                                                         OpenCapability::RouteRefresh,
 297                                                         OpenCapability::AddPath(vec![
 298                                                                 (AFI::IPV4, SAFI::Unicast, AddPathDirection::ReceivePaths),
 299                                                                 (AFI::IPV6, SAFI::Unicast, AddPathDirection::ReceivePaths)]),
 300                                                 ])]
 301                                         }));
 302                                         TimeoutStream::new_persistent(read, timeout).for_each(move |bgp_msg| {
 303                                                 if client.shutdown.load(Ordering::Relaxed) {
 304                                                         return future::err(std::io::Error::new(std::io::ErrorKind::Other, "Shutting Down"));
 305                                                 }
 306                                                 match bgp_msg {
 307                                                         Message::Open(_) => {
 308                                                                 client.routes.lock().unwrap().v4_table.clear();
 309                                                                 client.routes.lock().unwrap().v6_table.clear();
 310                                                                 printer.add_line("Connected to BGP route provider".to_string(), false);
 311                                                         },
 312                                                         Message::KeepAlive => {
 313                                                                 let _ = sender.try_send(Message::KeepAlive);
 314                                                         },
 315                                                         Message::Update(mut upd) => {
 316                                                                 upd.normalize();
 317                                                                 let mut route_table = client.routes.lock().unwrap();
 318                                                                 for r in upd.withdrawn_routes {
 319                                                                         route_table.withdraw(r);
 320                                                                 }
 321                                                                 if let Some(path) = Self::map_attrs(upd.attributes) {
 322                                                                         for r in upd.announced_routes {
 323                                                                                 route_table.announce(r, path.clone());
 324                                                                         }
 325                                                                 }
 326                                                                 printer.set_stat(Stat::V4RoutingTableSize(route_table.v4_table.len()));
 327                                                                 printer.set_stat(Stat::V6RoutingTableSize(route_table.v6_table.len()));
 328                                                         },
 329                                                         _ => {}
 330                                                 }
 331                                                 future::ok(())
 332                                         }).or_else(move |e| {
 333                                                 printer.add_line(format!("Got error from BGP stream: {:?}", e), true);
 334                                                 future::ok(())
 335                                         })
 336                                 }).then(move |_| {
 337                                         if !client_reconn.shutdown.load(Ordering::Relaxed) {
 338                                                 BGPClient::connect_given_client(addr, timeout, printer, client_reconn);
 339                                         }
 340                                         future::ok(())
 341                                 })
 342                         })
 343                 );
 344         }
 345
 346         pub fn new(addr: SocketAddr, timeout: Duration, printer: &'static Printer) -> Arc<BGPClient> {
 347                 let client = Arc::new(BGPClient {
 348                         routes: Mutex::new(RoutingTable::new()),
 349                         shutdown: AtomicBool::new(false),
 350                 });
 351                 BGPClient::connect_given_client(addr, timeout, printer, Arc::clone(&client));
 352                 client
 353         }
 354 }