Allow configuring the use of IPv6 and correctly handle unreachable errors

src/icmp.rs

@@ -11,12 +11,15 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+use std::sync::{Arc, RwLock};
+use std::time::Duration;
+
+use crate::util;
+
 use ekko::{Ekko, EkkoResponse};
 use gflags;
 use log::{error, info};
 use prometheus::{CounterVec, IntGaugeVec};
-use std::sync::{Arc, RwLock};
-use std::time::Duration;
 
 gflags::define! {
     /// The size in bytes of the ping requests.
@@ -44,8 +47,9 @@ pub fn start_echo_loop(
     ping_latency_guage: IntGaugeVec,
     ping_counter: CounterVec,
 ) {
-    info!("Pinging {}", domain_name);
-    let mut sender = Ekko::with_target(domain_name).unwrap();
+    let resolved = format!("{}", util::resolve_hosts(&vec![domain_name]).unwrap().first().unwrap().unwrap());
+    info!("Attempting to ping domain {} at address: {}", domain_name, resolved);
+    let mut sender = Ekko::with_target(&resolved).unwrap();
     loop {
         {
             // Limit the scope of this lock
@@ -54,35 +58,52 @@ pub fn start_echo_loop(
                 return;
             }
         }
-        let response = sender
-            .send_with_timeout(MAXHOPS.flag, Some(Duration::from_millis(PINGTIMEOUT.flag)))
-            .unwrap();
-        match response {
-            EkkoResponse::DestinationResponse(r) => {
-                info!(
-                    "ICMP: Reply from {}: time={}ms",
-                    r.address.unwrap(),
-                    r.elapsed.as_millis(),
-                );
-                ping_counter
-                    .with(&prometheus::labels! {"result" => "ok", "domain" => domain_name})
-                    .inc();
-                ping_latency_guage
-                    .with(&prometheus::labels! {"domain" => domain_name})
-                    .set(r.elapsed.as_millis() as i64);
-            }
-            EkkoResponse::ExceededResponse(_) => {
-                ping_counter
-                    .with(&prometheus::labels! {"result" => "timedout", "domain" => domain_name})
-                    .inc();
-            }
-            _ => {
-                ping_counter
-                    .with(&prometheus::labels! {"result" => "err", "domain" => domain_name})
-                    .inc();
-                error!("{:?}", response);
-            }
-        }
+        match sender
+            .send_with_timeout(MAXHOPS.flag, Some(Duration::from_millis(PINGTIMEOUT.flag))) {
+                Ok(r) => match r {
+                    EkkoResponse::DestinationResponse(r) => {
+                        info!(
+                            "ICMP: Reply from {}: time={}ms",
+                            r.address.unwrap(),
+                            r.elapsed.as_millis(),
+                        );
+                        ping_counter
+                            .with(&prometheus::labels! {"result" => "ok", "domain" => domain_name})
+                            .inc();
+                        ping_latency_guage
+                            .with(&prometheus::labels! {"domain" => domain_name})
+                            .set(r.elapsed.as_millis() as i64);
+                    }
+                    EkkoResponse::UnreachableResponse((_, ref _code)) => {
+                        // If we got unreachable we need to set up a new sender.
+                        error!("{:?}", r);
+                        info!("Restarting our sender");
+                        ping_counter
+                            .with(&prometheus::labels! {"result" => "unreachable", "domain" => domain_name})
+                            .inc();
+                        let mut new_sender = Ekko::with_target(&resolved).unwrap();
+                        std::mem::swap(&mut sender, &mut new_sender);
+
+                    }
+                    EkkoResponse::ExceededResponse(_) => {
+                        ping_counter
+                            .with(&prometheus::labels! {"result" => "timeout", "domain" => domain_name})
+                            .inc();
+                    }
+                    _ => {
+                        ping_counter
+                            .with(&prometheus::labels! {"result" => "err", "domain" => domain_name})
+                            .inc();
+                        error!("{:?}", r);
+                    }
+                },
+                Err(e) => {
+                    ping_counter
+                        .with(&prometheus::labels! {"result" => "err", "domain" => domain_name})
+                        .inc();
+                    error!("Ping send to {} failed: {:?}, Trying again later", domain_name, e);
+                }
+            };
         std::thread::sleep(Duration::from_secs(3));
     }
 }

src/main.rs

@@ -14,6 +14,7 @@
 
 use std::sync::Arc;
 use std::sync::RwLock;
+use std::convert::Into;
 
 use gflags;
 use log::{debug, error, info};
@@ -133,7 +134,7 @@ fn main() -> anyhow::Result<()> {
         .expect("Failed to register ping latency guage");
     r.register(Box::new(ping_counter_vec.clone()))
         .expect("Failed to register ping counter");
-    let stun_socket_addrs = util::resolve_addrs(&stun_servers).unwrap();
+    let stun_socket_addrs = util::resolve_socket_addrs(&stun_servers).unwrap();
     let stun_servers = Arc::new(stun_servers);
     let ping_hosts = Arc::new(ping_hosts);
 
@@ -202,7 +203,7 @@ fn main() -> anyhow::Result<()> {
                 stun::start_listen_thread(
                     domain_name,
                     stop_signal,
-                    s,
+                    s.into(),
                     stun_counter_vec_copy,
                     stun_latency_vec_copy,
                     stun_success_vec_copy,

src/util.rs

@@ -13,11 +13,33 @@
 // limitations under the License.
 
 use std::io;
+use std::net::IpAddr;
 use std::net::{SocketAddr, ToSocketAddrs};
 
 use log::info;
+use resolve::config::DnsConfig;
+use resolve::resolver::{DnsResolver};
+use gflags;
 
-pub fn resolve_addrs<'a>(servers: &'a Vec<&str>) -> io::Result<Vec<Option<SocketAddr>>> {
+gflags::define! {
+    /// Allow IPv6 addresses for domain name lookups.
+    --allowIpv6: bool = false
+}
+
+pub fn resolve_hosts<'a>(servers: &'a Vec<&str>) -> io::Result<Vec<Option<IpAddr>>> {
+    let mut results = Vec::new();
+    let mut config = DnsConfig::load_default()?;
+    config.use_inet6 = ALLOWIPV6.flag;
+    let resolver = DnsResolver::new(config)?;
+    for name in servers.iter().cloned() {
+        // TODO for resolution errors return a more valid error with the domain name.
+        let mut iter = resolver.resolve_host(name)?;
+        results.push(iter.next());
+    }
+    return Ok(results);
+}
+
+pub fn resolve_socket_addrs<'a>(servers: &'a Vec<&str>) -> io::Result<Vec<Option<SocketAddr>>> {
     let mut results = Vec::new();
     for name in servers.iter().cloned() {
         // TODO for resolution errors return a more valid error with the domain name.