Prioritization system

daemon/config.cc

@@ -63,7 +63,9 @@ Config::Config(const string& config_file_address)
 
 Config::Config(const asphr::json& config_json_input,
                const string& config_file_address)
-    : saved_file_address(config_file_address), db_rows_(CLIENT_DB_ROWS) {
+    : saved_file_address(config_file_address),
+      db_rows_(CLIENT_DB_ROWS),
+      dummyMe("dummyMe", 0, "", "", 0, false, 0, 0, 0, true) {
   auto config_json = config_json_input;
   if (!config_json.contains("has_registered")) {
     cout << "WARNING (invalid config file): config file does not contain "
@@ -112,7 +114,7 @@ Config::Config(const asphr::json& config_json_input,
 
   for (auto& friend_json : config_json.at("friends")) {
     Friend f = Friend::from_json(friend_json);
-    friendTable[f.name] = f;
+    friendTable.try_emplace(f.name, f);
   }
 
   data_dir = config_json.at("data_dir").get<string>();
@@ -194,14 +196,15 @@ auto Config::num_enabled_friends() -> int {
   return num_enabled_friends;
 }
 
-auto Config::random_enabled_friend() -> asphr::StatusOr<Friend> {
+auto Config::random_enabled_friend(const std::unordered_set<string>& excluded)
+    -> asphr::StatusOr<Friend> {
   const std::lock_guard<std::mutex> l(config_mtx);
 
   check_rep();
 
   vector<Friend> enabled_friends;
   for (auto& friend_pair : friendTable) {
-    if (friend_pair.second.enabled) {
+    if (friend_pair.second.enabled && !excluded.contains(friend_pair.first)) {
       enabled_friends.push_back(friend_pair.second);
     }
   }
@@ -231,7 +234,7 @@ auto Config::add_friend(const Friend& f) -> void {
   check_rep();
 
   assert(!friendTable.contains(f.name));
-  friendTable[f.name] = f;
+  friendTable.try_emplace(f.name, f);
 
   save();
   check_rep();
@@ -287,7 +290,7 @@ auto Config::update_friend(const Friend& f) -> void {
   check_rep();
 
   assert(friendTable.contains(f.name));
-  friendTable[f.name] = f;
+  friendTable.insert_or_assign(f.name, f);
   save();
 
   check_rep();
@@ -355,6 +358,7 @@ auto Config::check_rep() const -> void {
     assert(registrationInfo.allocation.size() > 0);
 
     assert(dummyMe.name == "dummyMe");
+    assert(dummyMe.dummy);
     assert(dummyMe.write_key.size() ==
            crypto_aead_xchacha20poly1305_ietf_KEYBYTES);
     assert(dummyMe.read_key.size() ==
@@ -400,7 +404,7 @@ auto Config::initialize_dummy_me() -> void {
       dummy_friend_keypair.first);
 
   dummyMe = Friend("dummyMe", 0, dummy_read_write_keys.first,
-                   dummy_read_write_keys.second, 0, false, 0, 0, 0);
+                   dummy_read_write_keys.second, 0, false, 0, 0, 0, true);
 
   save();
 }

daemon/config.hpp

@@ -45,7 +45,8 @@ class Config {
 
   auto has_space_for_friends() -> bool;
   auto num_enabled_friends() -> int;
-  auto random_enabled_friend() -> asphr::StatusOr<Friend>;
+  auto random_enabled_friend(const std::unordered_set<string>& excluded)
+      -> asphr::StatusOr<Friend>;
   auto dummy_me() -> Friend;
 
   auto has_registered() -> bool;

daemon/constants.hpp

@@ -23,6 +23,16 @@ constexpr auto DEFAULT_SERVER_ADDRESS = "server1.anysphere.co:443";
 // this commit hash will be automatically updated by gui/package.json.
 constexpr auto RELEASE_COMMIT_HASH = "32622be70c454ef4fc64517444727226d4df983b";
 
+// this is the number of friends that will be received from in each round
+// (ideally, they can all be received in a single PIR request using batch PIR)
+// it needs to be at least 2, or else we will get a liveness problem where we
+// are sending to one person who is not responding, and then continually trying
+// to read from that person while never receiving from anyone else.
+// TODO: when batch PIR implemented, increase this to the batch PIR number
+constexpr auto RECEIVE_FRIENDS_PER_ROUND = 2;
+static_assert(RECEIVE_FRIENDS_PER_ROUND >= 2,
+              "RECEIVE_FRIENDS_PER_ROUND must be >= 2");
+
 // this is copied from amazon-roots.pem
 // ideally we would do some kind of compile-time read file operation here, but
 // that seems to not exist

daemon/friend.cc

@@ -21,17 +21,15 @@ auto Friend::to_json() -> asphr::json {
 }
 
 auto Friend::from_json(const asphr::json& j) -> Friend {
-  Friend f;
-  f.name = j.at("name").get<string>();
-  f.read_index = j.at("read_index").get<int>();
-  asphr::Base64Unescape(j.at("write_key").get<string>(), &f.write_key);
-  asphr::Base64Unescape(j.at("read_key").get<string>(), &f.read_key);
-  f.ack_index = j.at("ack_index").get<int>();
-  f.enabled = j.at("enabled").get<bool>();
-  f.latest_ack_id = j.at("latest_ack_id").get<uint32_t>();
-  f.latest_send_id = j.at("latest_send_id").get<uint32_t>();
-  f.last_receive_id = j.at("last_receive_id").get<uint32_t>();
-  f.check_rep();
+  string read_key;
+  string write_key;
+  asphr::Base64Unescape(j.at("read_key").get<string>(), &read_key);
+  asphr::Base64Unescape(j.at("write_key").get<string>(), &write_key);
+  Friend f(j.at("name").get<string>(), j.at("read_index").get<int>(), read_key,
+           write_key, j.at("ack_index").get<int>(), j.at("enabled").get<bool>(),
+           j.at("latest_ack_id").get<uint32_t>(),
+           j.at("latest_send_id").get<uint32_t>(),
+           j.at("last_receive_id").get<uint32_t>(), false);
   return f;
 }
 

daemon/friend.hpp

@@ -10,7 +10,6 @@
 
 class Friend {
  public:
-  Friend() = default;
   Friend(const string& name, const vector<Friend>& friends)
       : name(name),
         read_index(0),
@@ -20,7 +19,8 @@ class Friend {
         enabled(false),
         latest_ack_id(0),
         latest_send_id(0),
-        last_receive_id(0) {
+        last_receive_id(0),
+        dummy(false) {
     auto rng = std::default_random_engine{};
 
     auto all_ack_indexes_not_used = asphr::unordered_set<int>{};
@@ -45,7 +45,7 @@ class Friend {
   Friend(const string& name, const int read_index, const string& read_key,
          const string& write_key, const int ack_index, const bool enabled,
          const uint32_t latest_ack_id, const uint32_t latest_send_id,
-         const uint32_t last_receive_id)
+         const uint32_t last_receive_id, bool dummy)
       : name(name),
         read_index(read_index),
         read_key(read_key),
@@ -54,7 +54,8 @@ class Friend {
         enabled(enabled),
         latest_ack_id(latest_ack_id),
         latest_send_id(latest_send_id),
-        last_receive_id(last_receive_id) {
+        last_receive_id(last_receive_id),
+        dummy(dummy) {
     check_rep();
   }
 
@@ -83,6 +84,8 @@ class Friend {
   // have received all IDs up to and including this value. Note that this refers
   // to ID in the sequence_number space, not the message ID space.
   uint32_t last_receive_id;
+  // dummy is true if the friend is a dummy friend!
+  bool dummy;
 
   auto to_json() -> asphr::json;
   static auto from_json(const asphr::json& j) -> Friend;

daemon/inbox.cc

@@ -134,7 +134,7 @@ auto Inbox::update_ack_from_friend(Config& config, pir_value_t& pir_acks,
 auto Inbox::receive_message(FastPIRClient& client, Config& config,
                             const asphrserver::ReceiveMessageResponse& reply,
                             const Friend& friend_info_in, const Crypto& crypto,
-                            string& previous_success_receive_friend)
+                            string* previous_success_receive_friend)
     -> std::optional<InboxMessage> {
   check_rep();
   Friend friend_info = friend_info_in;
@@ -167,8 +167,6 @@ auto Inbox::receive_message(FastPIRClient& client, Config& config,
          << decrypted.status() << endl;
     save();
     return std::nullopt;
-  } else {
-    previous_success_receive_friend = friend_info.name;
   }
   auto& message = decrypted.value();
 
@@ -214,6 +212,10 @@ auto Inbox::receive_message(FastPIRClient& client, Config& config,
     return std::nullopt;
   }
 
+  // we have received a new message (chunk) that we haven't received before!
+  // this is a success!
+  *previous_success_receive_friend = friend_info.name;
+
   if (message.num_chunks() == 0) {
     save();
     return InboxMessage{message.msg(), friend_info.name, message.id()};

daemon/inbox.hpp

@@ -42,7 +42,7 @@ class Inbox {
   auto receive_message(FastPIRClient& client, Config& config,
                        const asphrserver::ReceiveMessageResponse& reply,
                        const Friend& friend_info_in, const Crypto& crypto,
-                       string& previous_success_receive_friend)
+                       string* previous_success_receive_friend)
       -> std::optional<InboxMessage>;
 
  private:

daemon/outbox.cc

@@ -8,14 +8,14 @@
 #include "client_lib/client_lib.hpp"
 
 auto MessageToSend::from_json(const asphr::json& json) -> MessageToSend {
-  MessageToSend message;
-  message.to = Friend::from_json(json.at("to"));
-  message.sequence_number = json.at("sequence_number").get<uint32_t>();
-  message.msg = json.at("msg").get<string>();
-  message.chunked = json.at("chunked").get<bool>();
-  message.num_chunks = json.at("num_chunks").get<uint32_t>();
-  message.chunks_start_id = json.at("chunks_start_id").get<uint32_t>();
-  message.full_message_id = json.at("full_message_id").get<string>();
+  auto message = MessageToSend{
+      .to = Friend::from_json(json.at("to")),
+      .sequence_number = json.at("sequence_number").get<uint32_t>(),
+      .msg = json.at("msg").get<string>(),
+      .chunked = json.at("chunked").get<bool>(),
+      .num_chunks = json.at("num_chunks").get<uint32_t>(),
+      .chunks_start_id = json.at("chunks_start_id").get<uint32_t>(),
+      .full_message_id = json.at("full_message_id").get<string>()};
   return message;
 }