Add delay between handshake attempts

This avoids mod loading failure messages caused by partially copied mod
files after initial download, the same way it is already avoided while
loading files from cache.

Addresses some instances of
https://github.com/BeamMP/BeamMP-Launcher/issues/91

---

By creating this pull request, I understand that code that is AI
generated or otherwise automatically generated may be rejected without
further discussion.
I declare that I fully understand all code I pushed into this PR, and
wrote all this code myself and own the rights to this code.

include/Network/network.hpp

@@ -42,7 +42,7 @@ extern std::string magic;
 int KillSocket(uint64_t Dead);
 void UUl(const std::string& R);
 void UDPSend(std::string Data);
-bool CheckBytes(int32_t Bytes);
+bool CheckBytes(int32_t Bytes, int32_t Expected = -1);
 void GameSend(std::string_view Data);
 void SendLarge(std::string Data);
 std::string TCPRcv(uint64_t Sock);
@@ -56,3 +56,4 @@ void UDPClientMain(const std::string& IP, int Port);
 void TCPGameServer(const std::string& IP, int Port);
 bool SecurityWarning();
 void CoreSend(std::string data);
+int RecvWaitAll(int sockfd, char *buf, int len);

src/Network/Core.cpp

@@ -143,29 +143,28 @@ void GetServerInfo(std::string Data) {
     const std::string buffer = ([&]() -> std::string {
         int32_t Header;
         std::vector<char> data(sizeof(Header));
-        int Temp = recv(ISock, data.data(), sizeof(Header), MSG_WAITALL);
+        int Temp = RecvWaitAll(ISock, data.data(), sizeof(Header));
 
-        auto checkBytes = ([&](const int32_t bytes) -> bool {
+        auto checkBytes = ([&](const int32_t bytes, const int32_t expected = -1) -> bool {
             if (bytes == 0) {
                 return false;
             } else if (bytes < 0) {
                 return false;
             }
+            if (expected != -1 && bytes != expected) {
+                return false;
+            }
             return true;
         });
 
-        if (!checkBytes(Temp)) {
+        if (!checkBytes(Temp, sizeof(Header))) {
             return "";
         }
         memcpy(&Header, data.data(), sizeof(Header));
 
-        if (!checkBytes(Temp)) {
-            return "";
-        }
-
         data.resize(Header, 0);
-        Temp = recv(ISock, data.data(), Header, MSG_WAITALL);
+        Temp = RecvWaitAll(ISock, data.data(), Header);
-        if (!checkBytes(Temp)) {
+        if (!checkBytes(Temp, Header)) {
             return "";
         }
         return std::string(data.data(), Header);

src/Network/GlobalHandler.cpp

@@ -50,18 +50,11 @@ int KillSocket(uint64_t Dead) {
     return a;
 }
 
-bool CheckBytes(uint32_t Bytes) {
-    if (Bytes == 0) {
-        debug("(Proxy) Connection closing");
-        return false;
-    } else if (Bytes < 0) {
-        debug("(Proxy) send failed with error: " + std::to_string(WSAGetLastError()));
-        return false;
-    }
-    return true;
-}
-
 void GameSend(std::string_view Data) {
+    if (!GConnected) {
+        debug("Tried to call GameSend but socket was not connected. Data: " + std::string(Data));
+        return;
+    }
     static std::mutex Lock;
     std::scoped_lock Guard(Lock);
     auto ToSend = Utils::PrependHeader<std::string_view>(Data);
@@ -206,6 +199,7 @@ void ParserAsync(std::string_view Data) {
         return;
     case 'U':
         magic = Data.substr(1);
+        return;
     default:
         break;
     }

src/Network/Resources.cpp

@@ -163,8 +163,13 @@ std::vector<char> TCPRcvRaw(SOCKET Sock, uint64_t& GRcv, uint64_t Size) {
     int i = 0;
     do {
         // receive at most some MB at a time
-        int Len = std::min(int(Size - Rcv), 1 * 1024 * 1024);
+        uint64_t Len = std::min<uint64_t>((Size - Rcv), 1 * 1024 * 1024);
-        int Temp = recv(Sock, &File[Rcv], Len, MSG_WAITALL);
+        if (Len == 0) {
+            error("Download size miscalculation");
+            break;
+        }
+
+        int Temp = RecvWaitAll(Sock, &File[Rcv], Len);
         if (Temp == -1 || Temp == 0) {
             debug("Recv returned: " + std::to_string(Temp));
             if (Temp == -1) {
@@ -302,7 +307,7 @@ void InvalidResource(const std::string& File) {
 }
 
 struct ModInfo {
-    static std::pair<bool, std::vector<ModInfo>> ParseModInfosFromPacket(const std::string& packet) {
+    static std::optional<std::pair<bool, std::vector<ModInfo>>> ParseModInfosFromPacket(const std::string& packet) {
         bool success = false;
         std::vector<ModInfo> modInfos;
         try {
@@ -323,6 +328,12 @@ struct ModInfo {
                     modInfo.Protected = entry["protected"];
                 }
 
+                if (auto fsFile = std::filesystem::path(modInfo.FileName);
+                    !fsFile.has_filename() || fsFile.filename().string() != modInfo.FileName ||
+                    !fsFile.filename().has_extension() || fsFile.filename().extension() != ".zip"){
+                    return std::nullopt;
+                }
+
                 modInfos.push_back(modInfo);
                 success = true;
             }
@@ -578,8 +589,17 @@ void NewSyncResources(SOCKET Sock, const std::string& Mods, const std::vector<Mo
                 c = ::tolower(c);
             }
 #endif
+            auto name = std::filesystem::path(GetGamePath()) / "mods/multiplayer" / FName;
+            auto tmp_name = name;
+            tmp_name += ".tmp";
 
-            fs::copy_file(PathToSaveTo, std::filesystem::path(GetGamePath()) / "mods/multiplayer" / FName, fs::copy_options::overwrite_existing);
+            std::error_code ec;
+            fs::copy_file(PathToSaveTo, tmp_name, fs::copy_options::overwrite_existing, ec);
+            if (ec) {
+                error(beammp_wide("Error in copy_file during download of ") + beammp_fs_string(PathToSaveTo) + beammp_wide(": ") + Utils::ToWString(ec.message()));
+                break;
+            }
+            fs::rename(tmp_name, name);
             UpdateModUsage(FName);
         }
         WaitForConfirm();
@@ -602,7 +622,13 @@ void SyncResources(SOCKET Sock) {
     if (Ret.starts_with("R")) {
         debug("This server is likely outdated, not trying to parse new mod info format");
     } else {
-        auto [success, modInfo] = ModInfo::ParseModInfosFromPacket(Ret);
+        auto ParsedInfo = ModInfo::ParseModInfosFromPacket(Ret);
+        if (!ParsedInfo.has_value()) {
+            error("Invalid mod info");
+            Terminate = true;
+            return;
+        }
+        auto [success, modInfo] = ParsedInfo.value();
 
         if (success) {
             NewSyncResources(Sock, Ret, modInfo);
@@ -738,7 +764,12 @@ void SyncResources(SOCKET Sock) {
             }
 #endif
 
-            fs::copy_file(PathToSaveTo, GetGamePath() / beammp_wide("mods/multiplayer") / Utils::ToWString(FName), fs::copy_options::overwrite_existing);
+            auto name = GetGamePath() / beammp_wide("mods/multiplayer") / Utils::ToWString(FName);
+            auto tmp_name = name;
+            tmp_name += L".tmp";
+
+            fs::copy_file(PathToSaveTo, tmp_name, fs::copy_options::overwrite_existing);
+            fs::rename(tmp_name, name);
             UpdateModUsage(FN->substr(pos));
         }
         WaitForConfirm();

src/Network/VehicleData.cpp

@@ -7,6 +7,7 @@
 #include "Network/network.hpp"
 #include "Zlib/Compressor.h"
 #include <stdexcept>
+#include <thread>
 
 #if defined(_WIN32)
 #include <ws2tcpip.h>
@@ -93,9 +94,12 @@ void UDPClientMain(const std::string& IP, int Port) {
     ToServer->sin_port = htons(Port);
     inet_pton(AF_INET, IP.c_str(), &ToServer->sin_addr);
     UDPSock = socket(AF_INET, SOCK_DGRAM, 0);
-    if (!magic.empty())
+    if (!magic.empty()) {
-        for (int i = 0; i < 10; i++)
+        for (int i = 0; i < 10; i++) {
+            std::this_thread::sleep_for(std::chrono::milliseconds(10));
             UDPSend(magic);
+        }
+    }
     GameSend("P" + std::to_string(ClientID));
     TCPSend("H", TCPSock);
     UDPSend("p");

src/Network/VehicleEvent.cpp

@@ -28,9 +28,9 @@ int LastPort;
 std::string LastIP;
 SOCKET TCPSock = -1;
 
-bool CheckBytes(int32_t Bytes) {
+bool CheckBytes(int32_t Bytes, int32_t Expected) {
     if (Bytes == 0) {
-        debug("(TCP) Connection closing... CheckBytes(16)");
+        debug("(TCP) Connection closing...");
         Terminate = true;
         return false;
     } else if (Bytes < 0) {
@@ -39,6 +39,11 @@ bool CheckBytes(int32_t Bytes) {
         Terminate = true;
         return false;
     }
+    if (Expected != -1 && Bytes != Expected) {
+        debug(std::format("(TCP) Short recv detected, expected {} bytes, got {} bytes", Expected, Bytes));
+        Terminate = true;
+        return false;
+    }
     return true;
 }
 void UUl(const std::string& R) {
@@ -75,6 +80,24 @@ void TCPSend(const std::string& Data, uint64_t Sock) {
     } while (Sent < Size);
 }
 
+int RecvWaitAll(int sockfd, char *buf, int len) {
+    // handle MSG_WAITALL not actually filling the whole buffer
+    // happens frequently in wine, and can also happen natively when the OS pauses the execution for various reasons
+    int offset = 0;
+    while (offset < len) {
+        int recv_status = recv(sockfd, &buf[offset], len - offset, MSG_WAITALL);
+        if (recv_status == 0) {
+            // do not discard received data when the other side closes the socket cleanly
+            return offset;
+        }
+        if (recv_status == -1) {
+            return -1;
+        }
+        offset += recv_status;
+    }
+    return offset;
+}
+
 std::string TCPRcv(SOCKET Sock) {
     if (Sock == -1) {
         Terminate = true;
@@ -84,8 +107,8 @@ std::string TCPRcv(SOCKET Sock) {
     int32_t Header;
     int Temp;
     std::vector<char> Data(sizeof(Header));
-    Temp = recv(Sock, Data.data(), sizeof(Header), MSG_WAITALL);
+    Temp = RecvWaitAll(Sock, Data.data(), sizeof(Header));
-    if (!CheckBytes(Temp)) {
+    if (!CheckBytes(Temp, sizeof(Header))) {
         UUl("Socket Closed Code 3");
         return "";
     }
@@ -97,8 +120,8 @@ std::string TCPRcv(SOCKET Sock) {
     }
 
     Data.resize(Header, 0);
-    Temp = recv(Sock, Data.data(), Header, MSG_WAITALL);
+    Temp = RecvWaitAll(Sock, Data.data(), Header);
-    if (!CheckBytes(Temp)) {
+    if (!CheckBytes(Temp, Header)) {
         UUl("Socket Closed Code 5");
         return "";
     }

src/Startup.cpp

@@ -86,7 +86,7 @@ std::string GetVer() {
     return "2.8";
 }
 std::string GetPatch() {
-    return ".0";
+    return ".1";
 }
 
 beammp_fs_string GetEP(const beammp_fs_char* P) {