From f706b5366ed5d7b3bd82a1b1627b3203cc06ba78 Mon Sep 17 00:00:00 2001
From: SashaXser <24498484+SashaXser@users.noreply.github.com>
Date: Sun, 14 Apr 2024 21:40:03 +0400
Subject: [PATCH] mini optimization

---
 src/goodbyedpi.c | 44 ++++++++++++++++++--------------------------
 1 file changed, 18 insertions(+), 26 deletions(-)

diff --git a/src/goodbyedpi.c b/src/goodbyedpi.c
index cd5eabac..4587ef12 100644
--- a/src/goodbyedpi.c
+++ b/src/goodbyedpi.c
@@ -346,20 +346,23 @@ static int find_header_and_get_info(const char *pktdata, unsigned int pktlen,
                 char **hdrvalueaddr, unsigned int *hdrvaluelen) {
     char *data_addr_rn;
     char *hdr_begin;
+    size_t hdrname_len;
 
     *hdrvaluelen = 0u;
     *hdrnameaddr = NULL;
     *hdrvalueaddr = NULL;
 
+    hdrname_len = strlen(hdrname); // Calculate once
+
     /* Search for the header */
     hdr_begin = dumb_memmem(pktdata, pktlen,
-                hdrname, strlen(hdrname));
+                hdrname, hdrname_len);
     if (!hdr_begin) return FALSE;
     if (pktdata > hdr_begin) return FALSE;
 
     /* Set header address */
     *hdrnameaddr = hdr_begin;
-    *hdrvalueaddr = hdr_begin + strlen(hdrname);
+    *hdrvalueaddr = hdr_begin + hdrname_len;
 
     /* Search for header end (\r\n) */
     data_addr_rn = dumb_memmem(*hdrvalueaddr,
@@ -382,7 +385,7 @@ static int extract_sni(const char *pktdata, unsigned int pktlen,
     const unsigned char *hnaddr = NULL;
     int hnlen = 0;
 
-    while (pktlen >= 8) {
+    while (pktlen >= 9) { // Adjusted to account for minimum valid packet length
         if (*d == '\0' && *(d+1) == '\0' && *(d+2) == '\0' &&
             *(d+4) == '\0' && *(d+6) == '\0' && *(d+7) == '\0' &&
             *(d+3) - *(d+5) == 2 && *(d+5) - *(d+8) == 3)
@@ -390,19 +393,12 @@ static int extract_sni(const char *pktdata, unsigned int pktlen,
             hnaddr = d+9;
             hnlen = *(d+8);
 
-            if (hnlen < 3 || hnlen > HOST_MAXLEN) {
-                return FALSE;
-            }
-
-            if (pktlen < 8 + hnlen) {
+            if (hnlen < 3 || hnlen > HOST_MAXLEN || pktlen < 8 + hnlen) {
                 return FALSE;
             }
 
             for (int i = 0; i < hnlen; i++) {
-                if (!((hnaddr[i] >= '0' && hnaddr[i] <= '9') ||
-                      (hnaddr[i] >= 'a' && hnaddr[i] <= 'z') ||
-                      hnaddr[i] == '.' || hnaddr[i] == '-'))
-                {
+                if (!(isalnum(hnaddr[i]) || hnaddr[i] == '.' || hnaddr[i] == '-')) {
                     return FALSE;
                 }
             }
@@ -418,7 +414,6 @@ static int extract_sni(const char *pktdata, unsigned int pktlen,
     return FALSE;
 }
 
-
 static inline void change_window_size(const PWINDIVERT_TCPHDR ppTcpHdr, unsigned int size) {
     if (size >= 1 && size <= 0xFFFFu) {
         ppTcpHdr->Window = htons((u_short)size);
@@ -429,24 +424,24 @@ static inline void change_window_size(const PWINDIVERT_TCPHDR ppTcpHdr, unsigned
 static PVOID find_http_method_end(const char *pkt, unsigned int http_frag, int *is_fragmented) {
     unsigned int i;
     unsigned int pkt_length = strlen(pkt);
-    for (i = 0; i<(sizeof(http_methods) / sizeof(*http_methods)); i++) {
-        unsigned int method_length = strlen(http_methods[i]);
-        if (memcmp(pkt, http_methods[i], method_length) == 0) {
+    unsigned int methods_count = sizeof(http_methods) / sizeof(*http_methods);
+    unsigned int method_lengths[methods_count];
+    for (i = 0; i < methods_count; i++) {
+        method_lengths[i] = strlen(http_methods[i]);
+    }
+    for (i = 0; i < methods_count; i++) {
+        if (memcmp(pkt, http_methods[i], method_lengths[i]) == 0) {
             if (is_fragmented)
                 *is_fragmented = 0;
-            char *end = strchr(pkt + method_length, ' ');
+            char *end = strchr(pkt + method_lengths[i], ' ');
             if (end != NULL && end - pkt <= pkt_length)
                 return end;
         }
-        /* Try to find HTTP method in a second part of fragmented packet */
         if ((http_frag == 1 || http_frag == 2) &&
-            memcmp(pkt, http_methods[i] + http_frag,
-                        method_length - http_frag) == 0
-           )
-        {
+            memcmp(pkt, http_methods[i] + http_frag, method_lengths[i] - http_frag) == 0) {
             if (is_fragmented)
                 *is_fragmented = 1;
-            char *end = strchr(pkt + method_length - http_frag, ' ');
+            char *end = strchr(pkt + method_lengths[i] - http_frag, ' ');
             if (end != NULL && end - pkt <= pkt_length)
                 return end;
         }
@@ -454,9 +449,6 @@ static PVOID find_http_method_end(const char *pkt, unsigned int http_frag, int *
     return NULL;
 }
 
-
-
-
 /** Fragment and send the packet.
  *
  * This function cuts off the end of the packet (step=0) or