No longer hook GetHostName(), just store servers

amax-redirect.cfg

@@ -1,3 +1,3 @@
-lsg.demonware.net amax-emu.com
-blur-pc-live.auth.mmp3.demonware.net amax-emu.com
-blur-pc-live.lsg.mmp3.demonware.net amax-emu.com
+#0x0 lsg.demonware.net amax-emu.com
+0xAC5B3C blur-pc-live.auth.mmp3.demonware.net amax-emu.com
+0xAC5B64 blur-pc-live.lsg.mmp3.demonware.net amax-emu.com

source/dllmain.cpp

@@ -1,61 +1,86 @@
 #include <windows.h>
-#include <winsock.h>
-#include <libloaderapi.h>
-#include <stdint.h>
 
-//#include <iostream>
-#include <fstream> // used for std::ifstream input file reading
-#include <string> // std::string magic
-#include <map> // saving string key-value pairs in the input file
+#include <fstream> // used for reading std::ifstream input file
+#include <string>
+#include <vector>
 
-#pragma comment(lib, "ws2_32.lib") 
-#pragma comment(lib, "user32.lib") 
-
-
-#define HOOK_NET_FUNC_ADDY 0x92213B
-#define OP_CALL_LEN 6
 
+//TODO consider to give that file a better home / name?
 #define DNS_FILE_NAME "amax-redirect.cfg" // input file, must sit next to the amax-redirect.asi
 
 
-// global map for orignal->redirect domains
-std::map<std::string, std::string> dns_redirects;
-
-
-// parse input file and return domain pairs as map
-std::map<std::string, std::string> get_dns_redirects() {
-	std::map<std::string, std::string> r = {};
-	std::string key, value;
-	std::ifstream f(DNS_FILE_NAME);
-	while (f >> key >> value) {
-		r[key] = value;
+typedef struct {
+	uintptr_t addy; // offset from start Blur.exe where the entry is located
+	std::string org_host; // original hostname, in case we would want to restore it. TODO implement restore on unload?
+	std::string new_host; // new hostname
+} Redirect;
+
+
+// loads and parses entries from text file
+std::vector<Redirect> load_redirects(const char* filename) {
+	std::vector<Redirect> vec_redirects;
+	std::string str_addy;
+	uintptr_t addy;
+	std::string org_host;
+	std::string new_host;
+	std::ifstream f(filename);
+	while (f >> str_addy >> org_host >> new_host) { // this just eats every 3 string (anything), doesnt go line by line
+		if (str_addy[0] != '#') { // idk something with comments
+			if ((addy = std::strtol(str_addy.c_str(), NULL, 0)) > 0x0) {
+				// https://man7.org/linux/man-pages/man3/strtol.3.html
+				// (EXAMPLE: strtol("0xF") = 15 ) // converts string repr of number into actual number (accepts hex repr)
+				if (new_host.length() <= org_host.length()) {
+					Redirect r { addy, org_host, new_host };
+					vec_redirects.push_back(r);
+				} else {
+					// Inform user (by console or log file?) that one of the entries in filename is too long.
+					// TBH, I dont know how long (# of chars) they are allowed to be, should we check in Cheat-Engine?
+				}
+			} else {
+				// Could not convert string representation (hex 0x?) to actual addy
+			}
+		} else {
+			// It was a silly comment starting with '#'
+		}
 	}
-	return r;
+	return vec_redirects;
 }
 
 
-struct hostent* __stdcall hook_gethostbyname(const char* name) {
-	if (dns_redirects.count(name)) {
-		name = dns_redirects[name].c_str();
+bool set_redirects(uintptr_t moduleBase, std::vector<Redirect> vec_redirects) {
+	bool ok = true;
+	unsigned char* dst; // where we will write the new host string to
+	DWORD srcProtection, _; // for VirtualProtect, idk if its really needed?
+	for (Redirect r : vec_redirects) {
+		dst = (unsigned char*) (moduleBase + r.addy); // addy stored in cfg = offset from Blur.exe; so we add it to the base (moduleBase is almost always 0x40000)
+		VirtualProtect(dst, r.org_host.length(), PAGE_EXECUTE_READWRITE, &srcProtection);
+		// copy chars over, im sure there is more elegant way to do it...
+		for (unsigned int i = 0; i < r.new_host.length(); i++) {
+			// checking if the original chars match, unused so far...
+			ok = ok && (dst[i] == r.org_host[i]);
+			dst[i] = r.new_host[i];
+		}
+		// set the rest to null chars just in case
+		for (unsigned int i = r.new_host.length(); i < r.org_host.length(); i++) {
+			dst[i] = '\0';
+		}
+		VirtualProtect(dst, r.org_host.length(), srcProtection, &_);
 	}
-	return gethostbyname(name);
+	return ok;
 }
 
 
 BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpReserved) {
-	switch(fdwReason) { 
+	switch(fdwReason) {
 		case DLL_PROCESS_ATTACH: {
-			dns_redirects = get_dns_redirects();
-
 			uintptr_t moduleBase = (uintptr_t) GetModuleHandle(NULL);
-			void* src = (void*) (moduleBase + HOOK_NET_FUNC_ADDY);
-			void* callArg = VirtualAlloc(0, sizeof(uintptr_t), MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
-			*(uintptr_t*) callArg = (uintptr_t) hook_gethostbyname;
-
-			DWORD srcProtection, _;
-			VirtualProtect(src, OP_CALL_LEN, PAGE_EXECUTE_READWRITE, &srcProtection);
-			*(uintptr_t*) (((uint8_t*)src) + 2) = (uintptr_t) callArg;
-			VirtualProtect(src, OP_CALL_LEN, srcProtection, &_);
+			std::vector<Redirect> vec_redirects = load_redirects(DNS_FILE_NAME);
+			bool ok = set_redirects(moduleBase, vec_redirects);
+			if (ok) {
+				// Inform?
+			} else {
+				// IDK, restore?
+			}
 			break;
 
 		} case DLL_THREAD_ATTACH: { // Do thread-specific initialization.