Fix byte order for sessionid, add 64-bit conversion helpers - damn you C standard for no htonl/ntohl for 64-bit :(

CMakeLists.txt

@@ -6,7 +6,7 @@ cmake_minimum_required(VERSION 3.16)
 # If MAJOR is 0, and MINOR > 0, Version is BETA
 
 project(ColumnLynx
-    VERSION 0.0.3
+    VERSION 0.0.4
     LANGUAGES CXX
 )
 

include/columnlynx/common/net/virtual_interface.hpp

@@ -49,9 +49,9 @@ namespace ColumnLynx::Net {
             const std::string& getName() const;
             int getFd() const; // For ASIO integration (on POSIX)
 
-            static inline std::string ipToString(uint32_t ip) {
+            static inline std::string ipv4ToString(uint32_t ip) {
                 struct in_addr addr;
-                addr.s_addr = ip; // expected in network byte order
+                addr.s_addr = htonl(ip);
             
                 char buf[INET_ADDRSTRLEN];
                 if (!inet_ntop(AF_INET, &addr, buf, sizeof(buf)))
@@ -60,6 +60,12 @@ namespace ColumnLynx::Net {
                 return std::string(buf);
             }
 
+            static inline uint32_t prefixLengthToNetmask(uint8_t prefixLen) {
+                if (prefixLen == 0) return 0;
+                uint32_t mask = (0xFFFFFFFF << (32 - prefixLen)) & 0xFFFFFFFF;
+                return htonl(mask);    // convert to network byte order
+            }
+
         private:
             bool mApplyLinuxIP(uint32_t clientIP, uint32_t serverIP, uint8_t prefixLen, uint16_t mtu);
             bool mApplyMacOSIP(uint32_t clientIP, uint32_t serverIP, uint8_t prefixLen, uint16_t mtu);

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)
+    }
 };

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()));
     }
-}
+}

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

src/common/utils.cpp

@@ -37,7 +37,7 @@ namespace ColumnLynx::Utils {
     }
 
     std::string getVersion() {
-        return "a0.3";
+        return "a0.4";
     }
 
     unsigned short serverPort() {

src/common/virtual_interface.cpp

@@ -42,8 +42,11 @@ namespace ColumnLynx::Net {
         sc.sc_id = ctlInfo.ctl_id;
         sc.sc_unit = 0; // utun0 (0 = auto-assign)
 
-        if (connect(mFd, (struct sockaddr*)&sc, sizeof(sc)) < 0)
+        if (connect(mFd, (struct sockaddr*)&sc, sizeof(sc)) < 0) {
+            if (errno == EPERM)
+                throw std::runtime_error("connect(AF_SYS_CONTROL) failed: Insufficient permissions (try running as root)");
             throw std::runtime_error("connect(AF_SYS_CONTROL) failed: " + std::string(strerror(errno)));
+        }
 
         // Retrieve actual utun device name
         struct sockaddr_storage addr;
@@ -158,8 +161,8 @@ namespace ColumnLynx::Net {
     {
         char cmd[512];
     
-        std::string ipStr = ipToString(clientIP);
-        std::string peerStr = ipToString(serverIP);
+        std::string ipStr = ipv4ToString(clientIP);
+        std::string peerStr = ipv4ToString(serverIP);
     
         snprintf(cmd, sizeof(cmd),
                  "ip addr add %s/%d peer %s dev %s",
@@ -181,13 +184,16 @@ namespace ColumnLynx::Net {
     {
         char cmd[512];
     
-        std::string ipStr = ipToString(clientIP);
-        std::string peerStr = ipToString(serverIP);
+        std::string ipStr = ipv4ToString(clientIP);
+        std::string peerStr = ipv4ToString(serverIP);
     
+        // Set netmask (/24 CIDR temporarily with raw command, improve later)
         snprintf(cmd, sizeof(cmd),
-                "ifconfig utun0 %s %s mtu %d up",
+                "ifconfig utun0 %s %s mtu %d netmask 255.255.255.0 up",
                  ipStr.c_str(), peerStr.c_str(), mtu);
         system(cmd);
+
+        Utils::log("Executed command: " + std::string(cmd));
     
         return true;
     }
@@ -200,8 +206,8 @@ namespace ColumnLynx::Net {
     {
     #ifdef _WIN32
         char ip[32], gw[32];
-        strcpy(ip, ipToString(clientIP).c_str());
-        strcpy(gw, ipToString(serverIP).c_str());
+        strcpy(ip, ipv4ToString(clientIP).c_str());
+        strcpy(gw, ipv4ToString(serverIP).c_str());
     
         char cmd[256];
         snprintf(cmd, sizeof(cmd),

src/server/main.cpp

@@ -107,7 +107,7 @@ int main(int argc, char** argv) {
         
             auto session = SessionRegistry::getInstance().getByIP(dstIP);
             if (!session) {
-                Utils::warn("TUN: No session found for destination IP " + VirtualInterface::ipToString(dstIP));
+                Utils::warn("TUN: No session found for destination IP " + VirtualInterface::ipv4ToString(dstIP));
                 continue;
             }
 

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(