From d859a983678c4642671b79330b1664e40f8aabcc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C4=99drzej=20Stuczy=C5=84ski?=
 <jedrzej.stuczynski@gmail.com>
Date: Thu, 2 Apr 2020 15:39:14 +0100
Subject: [PATCH] Checking if any other node is already announcing the same
 host (#168)

---
 Cargo.lock                       |  2 ++
 mixnode/Cargo.toml               |  1 +
 mixnode/src/node/mod.rs          | 19 +++++++++++++++++++
 sfw-provider/Cargo.toml          |  1 +
 sfw-provider/src/provider/mod.rs | 23 +++++++++++++++++++++++
 5 files changed, 46 insertions(+)

diff --git a/Cargo.lock b/Cargo.lock
index 4d3b9027f8..549606f022 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1591,6 +1591,7 @@ dependencies = [
  "sphinx",
  "tempfile",
  "tokio 0.2.12",
+ "topology",
 ]
 
 [[package]]
@@ -1620,6 +1621,7 @@ dependencies = [
  "sphinx",
  "tempfile",
  "tokio 0.2.12",
+ "topology",
 ]
 
 [[package]]
diff --git a/mixnode/Cargo.toml b/mixnode/Cargo.toml
index 23614966a5..1d22c565c8 100644
--- a/mixnode/Cargo.toml
+++ b/mixnode/Cargo.toml
@@ -26,6 +26,7 @@ crypto = {path = "../common/crypto"}
 directory-client = { path = "../common/clients/directory-client" }
 multi-tcp-client = { path = "../common/clients/multi-tcp-client" }
 pemstore = {path = "../common/pemstore"}
+topology = {path = "../common/topology"}
 
 ## will be moved to proper dependencies once released
 sphinx = { git = "https://github.com/nymtech/sphinx", rev="44d8f2aece5049eaa4fe84b7948758ce82b4b80d" }
diff --git a/mixnode/src/node/mod.rs b/mixnode/src/node/mod.rs
index 80d0b6a743..ee992f9568 100644
--- a/mixnode/src/node/mod.rs
+++ b/mixnode/src/node/mod.rs
@@ -2,11 +2,13 @@ use crate::config::persistence::pathfinder::MixNodePathfinder;
 use crate::config::Config;
 use crate::node::packet_processing::PacketProcessor;
 use crypto::encryption;
+use directory_client::presence::Topology;
 use futures::channel::mpsc;
 use log::*;
 use pemstore::pemstore::PemStore;
 use std::net::SocketAddr;
 use tokio::runtime::Runtime;
+use topology::NymTopology;
 
 mod listener;
 mod metrics;
@@ -97,7 +99,24 @@ impl MixNode {
             .start(self.runtime.handle())
     }
 
+    fn check_if_same_ip_node_exists(&self) -> Option<String> {
+        // TODO: once we change to graph topology this here will need to be updated!
+        let topology = Topology::new(self.config.get_presence_directory_server());
+        let existing_mixes_presence = topology.mix_nodes;
+        existing_mixes_presence
+            .iter()
+            .find(|node| node.host == self.config.get_announce_address())
+            .map(|node| node.pub_key.clone())
+    }
+
     pub fn run(&mut self) {
+        if let Some(duplicate_node_key) = self.check_if_same_ip_node_exists() {
+            error!(
+                "Our announce-host is identical to one of existing nodes! (its key is {:?}",
+                duplicate_node_key
+            );
+            return;
+        }
         let forwarding_channel = self.start_packet_forwarder();
         let metrics_reporter = self.start_metrics_reporter();
         self.start_socket_listener(metrics_reporter, forwarding_channel);
diff --git a/sfw-provider/Cargo.toml b/sfw-provider/Cargo.toml
index 6e4e20dde9..63caeb06a8 100644
--- a/sfw-provider/Cargo.toml
+++ b/sfw-provider/Cargo.toml
@@ -29,6 +29,7 @@ config = {path = "../common/config"}
 directory-client = { path = "../common/clients/directory-client" }
 pemstore = {path = "../common/pemstore"}
 sfw-provider-requests = { path = "./sfw-provider-requests" }
+topology = {path = "../common/topology"}
 
 # this dependency is due to requiring to know content of loop message. however, mix-client module itself
 # is going to be removed or renamed at some point as it no longer servers its purpose of sending traffic to mix network
diff --git a/sfw-provider/src/provider/mod.rs b/sfw-provider/src/provider/mod.rs
index 78affe4264..b0a3b8ecfb 100644
--- a/sfw-provider/src/provider/mod.rs
+++ b/sfw-provider/src/provider/mod.rs
@@ -3,9 +3,11 @@ use crate::config::Config;
 use crate::provider::client_handling::ledger::ClientLedger;
 use crate::provider::storage::ClientStorage;
 use crypto::encryption;
+use directory_client::presence::Topology;
 use log::*;
 use pemstore::pemstore::PemStore;
 use tokio::runtime::Runtime;
+use topology::NymTopology;
 
 mod client_handling;
 mod mix_handling;
@@ -85,12 +87,33 @@ impl ServiceProvider {
         );
     }
 
+    fn check_if_same_ip_provider_exists(&self) -> Option<String> {
+        // TODO: once we change to graph topology this here will need to be updated!
+        let topology = Topology::new(self.config.get_presence_directory_server());
+        let existing_providers_presence = topology.mix_provider_nodes;
+        existing_providers_presence
+            .iter()
+            .find(|node| {
+                node.mixnet_listener == self.config.get_mix_announce_address()
+                    || node.client_listener == self.config.get_clients_announce_address()
+            })
+            .map(|node| node.pub_key.clone())
+    }
+
     pub fn run(&mut self) {
         // A possible future optimisation, depending on bottlenecks and resource usage:
         // considering, presumably, there will be more mix packets received than client requests:
         // create 2 separate runtimes - one with bigger threadpool dedicated solely for
         // the mix handling and the other one for the rest of tasks
 
+        if let Some(duplicate_provider_key) = self.check_if_same_ip_provider_exists() {
+            error!(
+                "Our announce-host is identical to one of existing nodes! (its key is {:?}",
+                duplicate_provider_key
+            );
+            return;
+        }
+
         let client_storage = ClientStorage::new(
             self.config.get_message_retrieval_limit() as usize,
             self.config.get_stored_messages_filename_length(),