From 15793fb84f8df7995907d9312ac19571b42f8dd0 Mon Sep 17 00:00:00 2001
From: ValdikSS <iam@valdikss.org.ru>
Date: Sat, 14 Sep 2024 22:35:28 +0300
Subject: [PATCH] --fake-gen option: generate random-filled Fake Packets

This option is similar to fake-from-hex, but generates number of
packets with random payload.
---
 README.md         |  2 ++
 src/fakepackets.c | 24 ++++++++++++++++++++++++
 src/goodbyedpi.c  |  8 ++++++++
 3 files changed, 34 insertions(+)

diff --git a/README.md b/README.md
index 0c0dabb..4f44951 100644
--- a/README.md
+++ b/README.md
@@ -67,6 +67,8 @@ Usage: goodbyedpi.exe [OPTION...]
  --fake-from-hex <value>  Load fake packets for Fake Request Mode from HEX values (like 1234abcDEF).
                           This option can be supplied multiple times, in this case each fake packet
                           would be sent on every request in the command line argument order.
+ --fake-gen <value>       Generate random-filled fake packets for Fake Request Mode, value of them
+                          (up to 30).
  --max-payload [value]    packets with TCP payload data more than [value] won't be processed.
                           Use this option to reduce CPU usage by skipping huge amount of data
                           (like file transfers) in already established sessions.
diff --git a/src/fakepackets.c b/src/fakepackets.c
index b7fb1e2..e13c271 100644
--- a/src/fakepackets.c
+++ b/src/fakepackets.c
@@ -1,4 +1,5 @@
 #include <stdio.h>
+#define _CRT_RAND_S
 #include <stdlib.h>
 #include <stdbool.h>
 #include <ctype.h>
@@ -284,3 +285,26 @@ int fake_load_from_hex(const char *data) {
 
     return fake_add(finaldata, len / 2);
 }
+
+int fake_load_random(unsigned int count, unsigned int maxsize) {
+    if (count < 1 || count > sizeof(fakes) / sizeof(*fakes))
+        return 1;
+
+    unsigned int random = 0;
+
+    for (unsigned int i=0; i<count; i++) {
+        unsigned int len = 0;
+        if (rand_s(&len))
+            return 1;
+        len = 8 + (len % maxsize);
+
+        unsigned char *data = calloc(len, 1);
+        for (unsigned int j=0; j<len; j++) {
+            rand_s(&random);
+            data[j] = random % 0xFF;
+        }
+        if (fake_add(data, len))
+            return 2;
+    }
+    return 0;
+}
diff --git a/src/goodbyedpi.c b/src/goodbyedpi.c
index bf43e19..40d7e00 100644
--- a/src/goodbyedpi.c
+++ b/src/goodbyedpi.c
@@ -189,6 +189,7 @@ static struct option long_options[] = {
     {"reverse-frag",no_argument,       0,  '(' },
     {"max-payload", optional_argument, 0,  '|' },
     {"fake-from-hex", required_argument, 0,  'u' },
+    {"fake-gen",    required_argument, 0,  'j' },
     {"debug-exit",  optional_argument, 0,  'x' },
     {0,             0,                 0,   0  }
 };
@@ -946,6 +947,11 @@ int main(int argc, char *argv[]) {
                     printf("WARNING: bad fake HEX value %s\n", optarg);
                 }
                 break;
+            case 'j': // --fake-gen
+                if (fake_load_random(atoub(optarg, "Fake generator parameter error!"))) {
+                    puts("WARNING: fake generator has failed!");
+                }
+                break;
             case 'x': // --debug-exit
                 debug_exit = true;
                 break;
@@ -997,6 +1003,8 @@ int main(int argc, char *argv[]) {
                 " --fake-from-hex <value>  Load fake packets for Fake Request Mode from HEX values (like 1234abcDEF).\n"
                 "                          This option can be supplied multiple times, in this case each fake packet\n"
                 "                          would be sent on every request in the command line argument order.\n"
+                " --fake-gen <value>       Generate random-filled fake packets for Fake Request Mode, value of them\n"
+                "                          (up to 30).\n"
                 " --max-payload [value]    packets with TCP payload data more than [value] won't be processed.\n"
                 "                          Use this option to reduce CPU usage by skipping huge amount of data\n"
                 "                          (like file transfers) in already established sessions.\n"