From 022debfa5be737e66e63742db3ee8a1d9571efdb Mon Sep 17 00:00:00 2001
From: DcruBro <info@dcrubro.com>
Date: Sat, 22 Nov 2025 21:53:45 +0100
Subject: [PATCH] Fix byte order for sessionid, add 64-bit conversion helpers -
 damn you C standard for no htonl/ntohl for 64-bit :(

---
 include/columnlynx/common/utils.hpp          | 19 +++++++++++++++++++
 src/client/main.cpp                          |  4 ++--
 src/client/net/tcp/tcp_client.cpp            |  3 +++
 src/server/server/net/tcp/tcp_connection.cpp |  6 +++---
 4 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/include/columnlynx/common/utils.hpp b/include/columnlynx/common/utils.hpp
index 46d77ea..d8026ba 100644
--- a/include/columnlynx/common/utils.hpp
+++ b/include/columnlynx/common/utils.hpp
@@ -38,4 +38,23 @@ namespace ColumnLynx::Utils {
     inline std::string uint8ArrayToString(const uint8_t* data, size_t length) {
         return std::string(reinterpret_cast<const char*>(data), length);
     }
+
+    inline constexpr uint64_t bswap64(uint64_t x) {
+        return ((x & 0x00000000000000FFULL) << 56) |
+               ((x & 0x000000000000FF00ULL) << 40) |
+               ((x & 0x0000000000FF0000ULL) << 24) |
+               ((x & 0x00000000FF000000ULL) << 8)  |
+               ((x & 0x000000FF00000000ULL) >> 8)  |
+               ((x & 0x0000FF0000000000ULL) >> 24) |
+               ((x & 0x00FF000000000000ULL) >> 40) |
+               ((x & 0xFF00000000000000ULL) >> 56);
+    }
+
+    inline constexpr uint64_t htobe64(uint64_t x) {
+        return bswap64(x);   // host -> big-endian (for little-endian hosts)
+    }
+
+    inline constexpr uint64_t be64toh(uint64_t x) {
+        return bswap64(x);   // big-endian -> host (for little-endian hosts)
+    }
 };
\ No newline at end of file
diff --git a/src/client/main.cpp b/src/client/main.cpp
index a331bf1..fb4a6d3 100644
--- a/src/client/main.cpp
+++ b/src/client/main.cpp
@@ -63,7 +63,7 @@ int main(int argc, char** argv) {
         WintunInitialize();
 #endif
 
-        std::shared_ptr<VirtualInterface> tun = std::make_shared<VirtualInterface>("utun0");
+        std::shared_ptr<VirtualInterface> tun = std::make_shared<VirtualInterface>("utun1");
         log("Using virtual interface: " + tun->getName());
 
         LibSodiumWrapper sodiumWrapper = LibSodiumWrapper();
@@ -111,4 +111,4 @@ int main(int argc, char** argv) {
     } catch (const std::exception& e) {
         error("Client error: " + std::string(e.what()));
     }
-}
\ No newline at end of file
+}
diff --git a/src/client/net/tcp/tcp_client.cpp b/src/client/net/tcp/tcp_client.cpp
index c6185e7..b7dc53c 100644
--- a/src/client/net/tcp/tcp_client.cpp
+++ b/src/client/net/tcp/tcp_client.cpp
@@ -247,6 +247,9 @@ namespace ColumnLynx::Net::TCP {
 
                     std::memcpy(&mConnectionSessionID, decrypted.data(), sizeof(mConnectionSessionID));
                     std::memcpy(&mTunConfig, decrypted.data() + sizeof(mConnectionSessionID), sizeof(Protocol::TunConfig));
+
+                    mConnectionSessionID = Utils::be64toh(mConnectionSessionID);
+
                     Utils::log("Connection established with Session ID: " + std::to_string(mConnectionSessionID));
                 
                     if (mSessionIDRef) { // Copy to the global reference
diff --git a/src/server/server/net/tcp/tcp_connection.cpp b/src/server/server/net/tcp/tcp_connection.cpp
index 4c0282f..dd902f6 100644
--- a/src/server/server/net/tcp/tcp_connection.cpp
+++ b/src/server/server/net/tcp/tcp_connection.cpp
@@ -173,8 +173,6 @@ namespace ColumnLynx::Net::TCP {
                     // Make a Session ID
                     randombytes_buf(&mConnectionSessionID, sizeof(mConnectionSessionID));
 
-                    // TODO: Make the session ID little-endian for network transmission
-
                     // Encrypt the Session ID with the established AES key (using symmetric encryption, nonce can be all zeros for this purpose)
                     Nonce symNonce{}; // All zeros
 
@@ -190,8 +188,10 @@ namespace ColumnLynx::Net::TCP {
 
                     SessionRegistry::getInstance().lockIP(mConnectionSessionID, clientIP);
 
+                    uint64_t sessionIDNet = Utils::htobe64(mConnectionSessionID);
+
                     std::vector<uint8_t> payload(sizeof(uint64_t) + sizeof(tunConfig));
-                    std::memcpy(payload.data(), &mConnectionSessionID, sizeof(uint64_t));
+                    std::memcpy(payload.data(), &sessionIDNet, sizeof(uint64_t));
                     std::memcpy(payload.data() + sizeof(uint64_t), &tunConfig, sizeof(tunConfig));
 
                     std::vector<uint8_t> encryptedPayload = Utils::LibSodiumWrapper::encryptMessage(