From f6c1c695433c38a4d6f06c7d89a125b1cd1bb95e Mon Sep 17 00:00:00 2001
From: SashaXser <24498484+SashaXser@users.noreply.github.com>
Date: Sun, 10 Sep 2023 14:43:52 +0400
Subject: [PATCH] Update goodbyedpi.c

---
 src/goodbyedpi.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/src/goodbyedpi.c b/src/goodbyedpi.c
index 116e6b5..095208e 100644
--- a/src/goodbyedpi.c
+++ b/src/goodbyedpi.c
@@ -177,21 +177,17 @@ static struct option long_options[] = {
 static char *filter_string = NULL;
 static char *filter_passive_string = NULL;
 
-static void add_maxpayloadsize_str(unsigned short maxpayload) {
-    const char *maxpayloadsize_str = "and (tcp.PayloadLength ? tcp.PayloadLength < %hu or tcp.Payload32[0] == 0x47455420 or tcp.Payload32[0] == 0x504F5354 : true)";
-    char *addfilter = malloc(strlen(maxpayloadsize_str) + 16);
+static void add_filter_str(int proto, int port) {
+    const char *udp = " or (udp and !impostor and !loopback and (udp.SrcPort == %d or udp.DstPort == %d))";
+    const char *tcp = " or (tcp and !impostor and !loopback " MAXPAYLOADSIZE_TEMPLATE " and (tcp.SrcPort == %d or tcp.DstPort == %d))";
 
-    sprintf(addfilter, maxpayloadsize_str, maxpayload);
-
-    char *newstr = repl_str(filter_string, MAXPAYLOADSIZE_TEMPLATE, addfilter);
-    free(filter_string);
-    filter_string = newstr;
+    size_t new_filter_size = strlen(filter_string) + (proto == IPPROTO_UDP ? strlen(udp) : strlen(tcp)) + 16;
+    char *new_filter = malloc(new_filter_size);
 
-    newstr = repl_str(filter_passive_string, MAXPAYLOADSIZE_TEMPLATE, addfilter);
-    free(filter_passive_string);
-    filter_passive_string = newstr;
+    sprintf(new_filter, proto == IPPROTO_UDP ? udp : tcp, port, port);
 
-    free(addfilter); // Free the allocated memory
+    free(filter_string);
+    filter_string = new_filter;
 }
 
 static void add_ip_id_str(int id) {
@@ -1470,4 +1466,4 @@ int main(int argc, char *argv[]) {
             break;
         }
     }
-}
\ No newline at end of file
+}