_ 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::ops::Bound::Included;
   5 use std::collections::BTreeMap;
   6 use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr};
   7 use std::time::{Duration, Instant};
   8
   9 use bgp_rs::{AFI, SAFI, AddPathDirection, Open, OpenCapability, OpenParameter, NLRIEncoding, PathAttribute};
  10 use bgp_rs::Capabilities;
  11 use bgp_rs::Segment;
  12 use bgp_rs::Message;
  13 use bgp_rs::Reader;
  14
  15 use tokio::prelude::*;
  16 use tokio::codec;
  17 use tokio::codec::Framed;
  18 use tokio::net::TcpStream;
  19 use tokio::timer::Delay;
  20
  21 use futures::sync::mpsc;
  22
  23 use crate::printer::{Printer, Stat};
  24 use crate::timeout_stream::TimeoutStream;
  25
  26 struct Route {
  27         path: Vec<u32>,
  28         pref: u32,
  29         med: u32,
  30 }
  31
  32 struct RoutingTable {
  33         v4_table: BTreeMap<(Ipv4Addr, u8, u32), Arc<Route>>,
  34         v6_table: BTreeMap<(Ipv6Addr, u8, u32), Arc<Route>>,
  35 }
  36
  37 impl RoutingTable {
  38         fn new() -> Self {
  39                 Self {
  40                         v4_table: BTreeMap::new(),
  41                         v6_table: BTreeMap::new(),
  42                 }
  43         }
  44
  45         fn get_route_attrs(&self, ip: IpAddr) -> Vec<Arc<Route>> {
  46                 macro_rules! lookup_res {
  47                         ($addrty: ty, $addr: expr, $table: expr, $addr_bits: expr) => { {
  48                                 let mut res = Vec::new();
  49                                 //TODO: Optimize this!
  50                                 for i in (0..$addr_bits).rev() {
  51                                         let mut lookup = $addr.octets();
  52                                         for b in 0..(i / 8) {
  53                                                 lookup[lookup.len() - b - 1] = 0;
  54                                         }
  55                                         lookup[lookup.len() - (i/8) - 1] &= !(((1u16 << (i % 8)) - 1) as u8);
  56                                         let lookup_addr = <$addrty>::from(lookup);
  57                                         for attrs in $table.range((Included((lookup_addr, $addr_bits - i as u8, 0)), Included((lookup_addr, $addr_bits - i as u8, std::u32::MAX)))) {
  58                                                 res.push(Arc::clone(&attrs.1));
  59                                         }
  60                                         if !res.is_empty() { break; }
  61                                 }
  62                                 res
  63                         } }
  64                 }
  65                 match ip {
  66                         IpAddr::V4(v4a) => lookup_res!(Ipv4Addr, v4a, self.v4_table, 32),
  67                         IpAddr::V6(v6a) => lookup_res!(Ipv6Addr, v6a, self.v6_table, 128)
  68                 }
  69         }
  70
  71         fn withdraw(&mut self, route: NLRIEncoding) {
  72                 match route {
  73                         NLRIEncoding::IP(p) => {
  74                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
  75                                 match ip {
  76                                         IpAddr::V4(v4a) => self.v4_table.remove(&(v4a, len, 0)),
  77                                         IpAddr::V6(v6a) => self.v6_table.remove(&(v6a, len, 0)),
  78                                 }
  79                         },
  80                         NLRIEncoding::IP_WITH_PATH_ID((p, id)) => {
  81                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
  82                                 match ip {
  83                                         IpAddr::V4(v4a) => self.v4_table.remove(&(v4a, len, id)),
  84                                         IpAddr::V6(v6a) => self.v6_table.remove(&(v6a, len, id)),
  85                                 }
  86                         },
  87                         NLRIEncoding::IP_MPLS(_) => None,
  88                 };
  89         }
  90
  91         fn announce(&mut self, prefix: NLRIEncoding, route: Arc<Route>) {
  92                 match prefix {
  93                         NLRIEncoding::IP(p) => {
  94                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
  95                                 match ip {
  96                                         IpAddr::V4(v4a) => self.v4_table.insert((v4a, len, 0), route),
  97                                         IpAddr::V6(v6a) => self.v6_table.insert((v6a, len, 0), route),
  98                                 }
  99                         },
 100                         NLRIEncoding::IP_WITH_PATH_ID((p, id)) => {
 101                                 let (ip, len) = <(IpAddr, u8)>::from(&p);
 102                                 match ip {
 103                                         IpAddr::V4(v4a) => self.v4_table.insert((v4a, len, id), route),
 104                                         IpAddr::V6(v6a) => self.v6_table.insert((v6a, len, id), route),
 105                                 }
 106                         },
 107                         NLRIEncoding::IP_MPLS(_) => None,
 108                 };
 109         }
 110 }
 111
 112 struct BytesCoder<'a>(&'a mut bytes::BytesMut);
 113 impl<'a> std::io::Write for BytesCoder<'a> {
 114         fn write(&mut self, b: &[u8]) -> Result<usize, std::io::Error> {
 115                 self.0.extend_from_slice(&b);
 116                 Ok(b.len())
 117         }
 118         fn flush(&mut self) -> Result<(), std::io::Error> {
 119                 Ok(())
 120         }
 121 }
 122 struct BytesDecoder<'a> {
 123         buf: &'a mut bytes::BytesMut,
 124         pos: usize,
 125 }
 126 impl<'a> std::io::Read for BytesDecoder<'a> {
 127         fn read(&mut self, b: &mut [u8]) -> Result<usize, std::io::Error> {
 128                 let copy_len = cmp::min(b.len(), self.buf.len() - self.pos);
 129                 b[..copy_len].copy_from_slice(&self.buf[self.pos..self.pos + copy_len]);
 130                 self.pos += copy_len;
 131                 Ok(copy_len)
 132         }
 133 }
 134
 135 struct MsgCoder<'a>(&'a Printer);
 136 impl<'a> codec::Decoder for MsgCoder<'a> {
 137         type Item = Message;
 138         type Error = std::io::Error;
 139
 140         fn decode(&mut self, bytes: &mut bytes::BytesMut) -> Result<Option<Message>, std::io::Error> {
 141                 let mut decoder = BytesDecoder {
 142                         buf: bytes,
 143                         pos: 0
 144                 };
 145                 match (Reader {
 146                         stream: &mut decoder,
 147                         capabilities: Capabilities {
 148                                 FOUR_OCTET_ASN_SUPPORT: true,
 149                                 EXTENDED_PATH_NLRI_SUPPORT: true,
 150                         }
 151                 }).read() {
 152                         Ok((_header, msg)) => {
 153                                 decoder.buf.advance(decoder.pos);
 154                                 Ok(Some(msg))
 155                         },
 156                         Err(e) => match e.kind() {
 157                                 std::io::ErrorKind::UnexpectedEof => Ok(None),
 158                                 _ => Err(e),
 159                         },
 160                 }
 161         }
 162 }
 163 impl<'a> codec::Encoder for MsgCoder<'a> {
 164         type Item = Message;
 165         type Error = std::io::Error;
 166
 167         fn encode(&mut self, msg: Message, res: &mut bytes::BytesMut) -> Result<(), std::io::Error> {
 168                 msg.write(&mut BytesCoder(res))?;
 169                 Ok(())
 170         }
 171 }
 172
 173 pub struct BGPClient {
 174         routes: Mutex<RoutingTable>,
 175         shutdown: AtomicBool,
 176 }
 177 impl BGPClient {
 178         pub fn get_asn(&self, addr: IpAddr) -> u32 {
 179                 let mut path_vecs = self.routes.lock().unwrap().get_route_attrs(addr).clone();
 180                 if path_vecs.is_empty() { return 0; }
 181
 182                 path_vecs.sort_unstable_by(|path_a, path_b| {
 183                         path_a.pref.cmp(&path_b.pref)
 184                                 .then(path_b.path.len().cmp(&path_a.path.len()))
 185                                 .then(path_b.med.cmp(&path_a.med))
 186                 });
 187
 188                 let primary_route = path_vecs.pop().unwrap();
 189                 'asn_candidates: for asn in primary_route.path.iter().rev() {
 190                         for secondary_route in path_vecs.iter() {
 191                                 if !secondary_route.path.contains(asn) {
 192                                         continue 'asn_candidates;
 193                                 }
 194                         }
 195                         return *asn;
 196                 }
 197                 *primary_route.path.last().unwrap_or(&0)
 198         }
 199
 200         pub fn disconnect(&self) {
 201                 self.shutdown.store(true, Ordering::Relaxed);
 202         }
 203
 204         fn map_attrs(mut attrs: Vec<PathAttribute>) -> Option<Route> {
 205                 let mut as4_path = None;
 206                 let mut as_path = None;
 207                 let mut pref = 100;
 208                 let mut med = 0;
 209                 for attr in attrs.drain(..) {
 210                         match attr {
 211                                 PathAttribute::AS4_PATH(path) => as4_path = Some(path),
 212                                 PathAttribute::AS_PATH(path) => as_path = Some(path),
 213                                 PathAttribute::LOCAL_PREF(p) => pref = p,
 214                                 PathAttribute::MULTI_EXIT_DISC(m) => med = m,
 215                                 _ => {},
 216                         }
 217                 }
 218                 if let Some(mut aspath) = as4_path.or(as_path) {
 219                         let mut path = Vec::new();
 220                         for seg in aspath.segments.drain(..) {
 221                                 match seg {
 222                                         Segment::AS_SEQUENCE(mut asn) => path.append(&mut asn),
 223                                         Segment::AS_SET(_) => {}, // Ignore sets for now, they're not that common anyway
 224                                 }
 225                         }
 226                         return Some(Route {
 227                                 path: path.clone(),
 228                                 pref,
 229                                 med,
 230                         })
 231                 } else { None }
 232         }
 233
 234         fn connect_given_client(addr: SocketAddr, timeout: Duration, printer: &'static Printer, client: Arc<BGPClient>) {
 235                 tokio::spawn(Delay::new(Instant::now() + timeout / 4).then(move |_| {
 236                         let connect_timeout = Delay::new(Instant::now() + timeout.clone()).then(|_| {
 237                                 future::err(std::io::Error::new(std::io::ErrorKind::TimedOut, "timeout reached"))
 238                         });
 239                         let client_reconn = Arc::clone(&client);
 240                         TcpStream::connect(&addr).select(connect_timeout)
 241                                 .or_else(move |_| {
 242                                         Delay::new(Instant::now() + timeout / 2).then(|_| {
 243                                                 future::err(())
 244                                         })
 245                                 }).and_then(move |stream| {
 246                                         let (write, read) = Framed::new(stream.0, MsgCoder(printer)).split();
 247                                         let (mut sender, receiver) = mpsc::channel(10); // We never really should send more than 10 messages unless they're dumb
 248                                         tokio::spawn(write.sink_map_err(|_| { () }).send_all(receiver)
 249                                                 .then(|_| {
 250                                                         future::err(())
 251                                                 }));
 252                                         let _ = sender.try_send(Message::Open(Open {
 253                                                 version: 4,
 254                                                 peer_asn: 23456,
 255                                                 hold_timer: timeout.as_secs() as u16,
 256                                                 identifier: 0x453b1215, // 69.59.18.21
 257                                                 parameters: vec![OpenParameter::Capabilities(vec![
 258                                                         OpenCapability::MultiProtocol((AFI::IPV4, SAFI::Unicast)),
 259                                                         OpenCapability::MultiProtocol((AFI::IPV6, SAFI::Unicast)),
 260                                                         OpenCapability::FourByteASN(397444),
 261                                                         OpenCapability::RouteRefresh,
 262                                                         OpenCapability::AddPath(vec![
 263                                                                 (AFI::IPV4, SAFI::Unicast, AddPathDirection::ReceivePaths),
 264                                                                 (AFI::IPV6, SAFI::Unicast, AddPathDirection::ReceivePaths)]),
 265                                                 ])]
 266                                         }));
 267                                         TimeoutStream::new_persistent(read, timeout).for_each(move |bgp_msg| {
 268                                                 if client.shutdown.load(Ordering::Relaxed) {
 269                                                         return future::err(std::io::Error::new(std::io::ErrorKind::Other, "Shutting Down"));
 270                                                 }
 271                                                 match bgp_msg {
 272                                                         Message::Open(_) => {
 273                                                                 client.routes.lock().unwrap().v4_table.clear();
 274                                                                 client.routes.lock().unwrap().v6_table.clear();
 275                                                                 printer.add_line("Connected to BGP route provider".to_string(), false);
 276                                                         },
 277                                                         Message::KeepAlive => {
 278                                                                 let _ = sender.try_send(Message::KeepAlive);
 279                                                         },
 280                                                         Message::Update(mut upd) => {
 281                                                                 upd.normalize();
 282                                                                 let mut route_table = client.routes.lock().unwrap();
 283                                                                 for r in upd.withdrawn_routes {
 284                                                                         route_table.withdraw(r);
 285                                                                 }
 286                                                                 if let Some(path) = Self::map_attrs(upd.attributes) {
 287                                                                         let path_arc = Arc::new(path);
 288                                                                         for r in upd.announced_routes {
 289                                                                                 route_table.announce(r, Arc::clone(&path_arc));
 290                                                                         }
 291                                                                 }
 292                                                                 printer.set_stat(Stat::V4RoutingTableSize(route_table.v4_table.len()));
 293                                                                 printer.set_stat(Stat::V6RoutingTableSize(route_table.v6_table.len()));
 294                                                         },
 295                                                         _ => {}
 296                                                 }
 297                                                 future::ok(())
 298                                         }).or_else(move |e| {
 299                                                 printer.add_line(format!("Got error from BGP stream: {:?}", e), true);
 300                                                 future::ok(())
 301                                         })
 302                                 }).then(move |_| {
 303                                         if !client_reconn.shutdown.load(Ordering::Relaxed) {
 304                                                 BGPClient::connect_given_client(addr, timeout, printer, client_reconn);
 305                                         }
 306                                         future::ok(())
 307                                 })
 308                         })
 309                 );
 310         }
 311
 312         pub fn new(addr: SocketAddr, timeout: Duration, printer: &'static Printer) -> Arc<BGPClient> {
 313                 let client = Arc::new(BGPClient {
 314                         routes: Mutex::new(RoutingTable::new()),
 315                         shutdown: AtomicBool::new(false),
 316                 });
 317                 BGPClient::connect_given_client(addr, timeout, printer, Arc::clone(&client));
 318                 client
 319         }
 320 }