Select only ASNs visible in all paths for an IP

diff --git a/src/bgp_client.rs b/src/bgp_client.rs
index a96de047731edc1bf0e958e61394e66d248f4a6a..1fa92501c2601ee16ed28c4cec4661e935a44c83 100644 (file)
--- a/src/bgp_client.rs
+++ b/src/bgp_client.rs
@@ -176,13 +176,24 @@ pub struct BGPClient {
 impl BGPClient {
        pub fn get_asn(&self, addr: IpAddr) -> u32 {
                let mut path_vecs = self.routes.lock().unwrap().get_route_attrs(addr).clone();
+               if path_vecs.is_empty() { return 0; }
+
                path_vecs.sort_unstable_by(|path_a, path_b| {
                        path_a.pref.cmp(&path_b.pref)
                                .then(path_b.path.len().cmp(&path_a.path.len()))
                                .then(path_b.med.cmp(&path_a.med))
                });
-               // TODO: Find last common ASN among all paths
-               *path_vecs.first().map(|route| route.path.last().unwrap_or(&0)).unwrap_or(&0)
+
+               let primary_route = path_vecs.pop().unwrap();
+               'asn_candidates: for asn in primary_route.path.iter().rev() {
+                       for secondary_route in path_vecs.iter() {
+                               if !secondary_route.path.contains(asn) {
+                                       continue 'asn_candidates;
+                               }
+                       }
+                       return *asn;
+               }
+               *primary_route.path.last().unwrap_or(&0)
        }
 
        pub fn disconnect(&self) {