Fix AS path detection

[dnsseed-rust] / src / bgp_client.rs

diff --git a/src/bgp_client.rs b/src/bgp_client.rs
index dc5c6736a923fdfdbc2487d0fc51e2718034a40e..8dfb3eba579d94cbc0c3297f1cea9a6e7fccca1a 100644 (file)
--- a/src/bgp_client.rs
+++ b/src/bgp_client.rs
@@ -22,7 +22,7 @@ use futures::sync::mpsc;
 use crate::printer::{Printer, Stat};
 use crate::timeout_stream::TimeoutStream;
 
-const PATH_SUFFIX_LEN: usize = 2;
+const PATH_SUFFIX_LEN: usize = 3;
 #[derive(Clone)]
 struct Route { // 32 bytes with a path id u32
        path_suffix: [u32; PATH_SUFFIX_LEN],
@@ -31,7 +31,7 @@ struct Route { // 32 bytes with a path id u32
        med: u32,
 }
 #[allow(dead_code)]
-const ROUTE_LEN: usize = 32 - std::mem::size_of::<(u32, Route)>();
+const ROUTE_LEN: usize = 36 - std::mem::size_of::<(u32, Route)>();
 
 // To keep memory tight (and since we dont' need such close alignment), newtype the v4/v6 routing
 // table entries to make sure they are aligned to single bytes.
@@ -84,8 +84,8 @@ struct RoutingTable {
 impl RoutingTable {
        fn new() -> Self {
                Self {
-                       v4_table: HashMap::new(),
-                       v6_table: HashMap::new(),
+                       v4_table: HashMap::with_capacity(900_000),
+                       v6_table: HashMap::with_capacity(100_000),
                }
        }
 
@@ -145,7 +145,6 @@ impl RoutingTable {
                        NLRIEncoding::IP_MPLS_WITH_PATH_ID(_) => (),
                        NLRIEncoding::IP_VPN_MPLS(_) => (),
                        NLRIEncoding::L2VPN(_) => (),
-                       NLRIEncoding::FLOWSPEC(_) => (),
                };
        }
 
@@ -176,7 +175,6 @@ impl RoutingTable {
                        NLRIEncoding::IP_MPLS_WITH_PATH_ID(_) => (),
                        NLRIEncoding::IP_VPN_MPLS(_) => (),
                        NLRIEncoding::L2VPN(_) => (),
-                       NLRIEncoding::FLOWSPEC(_) => (),
                };
        }
 }
@@ -222,6 +220,9 @@ impl codec::Decoder for MsgCoder {
                match reader.read() {
                        Ok((_header, msg)) => {
                                decoder.buf.advance(decoder.pos);
+                               if let Message::Open(ref o) = &msg {
+                                       self.0 = Some(Capabilities::from_parameters(o.parameters.clone()));
+                               }
                                Ok(Some(msg))
                        },
                        Err(e) => match e.kind() {
@@ -258,14 +259,35 @@ impl BGPClient {
                });
 
                let primary_route = path_vecs.pop().unwrap();
-               'asn_candidates: for asn in primary_route.path_suffix.iter().rev() {
-                       if *asn == 0 { continue 'asn_candidates; }
-                       for secondary_route in path_vecs.iter() {
-                               if !secondary_route.path_suffix.contains(asn) {
-                                       continue 'asn_candidates;
+               if path_vecs.len() > 3 {
+                       // If we have at least 3 paths, try to find the last unique ASN which doesn't show up in other paths
+                       // If we hit a T1 that is reasonably assumed to care about net neutrality, return the
+                       // previous ASN.
+                       let mut prev_asn = 0;
+                       'asn_candidates: for asn in primary_route.path_suffix.iter().rev() {
+                               if *asn == 0 { continue 'asn_candidates; }
+                               match *asn {
+                                       // Included: CenturyLink (L3), Cogent, Telia, NTT, GTT, Level3,
+                                       //           GBLX (L3), Zayo, TI Sparkle Seabone, HE, Telefonica
+                                       // Left out from Caida top-20: TATA, PCCW, Vodafone, RETN, Orange, Telstra,
+                                       //                             Singtel, Rostelecom, DTAG
+                                       209|174|1299|2914|3257|3356|3549|6461|6762|6939|12956 if prev_asn != 0 => return prev_asn,
+                                       _ => if path_vecs.iter().any(|route| !route.path_suffix.contains(asn)) {
+                                               if prev_asn != 0 { return prev_asn } else {
+                                                       // Multi-origin prefix, just give up and take the last AS in the
+                                                       // default path
+                                                       break 'asn_candidates;
+                                               }
+                                       } else {
+                                               // We only ever possibly return an ASN if it appears in all paths
+                                               prev_asn = *asn;
+                                       },
                                }
                        }
-                       return *asn;
+                       // All paths were the same, if the first ASN is non-0, return it.
+                       if prev_asn != 0 {
+                               return prev_asn;
+                       }
                }
 
                for asn in primary_route.path_suffix.iter().rev() {