Improvements for dta dissection

2 files changed, 36 insertions, 13 deletions

diff --git a/src/include/ndpi_api.h b/src/include/ndpi_api.h
index f2b03774f..d5cc9ad15 100644
--- a/src/include/ndpi_api.h
+++ b/src/include/ndpi_api.h
@@ -812,7 +812,9 @@ extern "C" {
   u_int16_t ndpi_guess_host_protocol_id(struct ndpi_detection_module_struct *ndpi_struct,
 					struct ndpi_flow_struct *flow);
   int ndpi_has_human_readeable_string(struct ndpi_detection_module_struct *ndpi_struct,
-				      char *buffer, u_int buffer_size);
+				      char *buffer, u_int buffer_size,
+				      u_int8_t min_string_match_len, /* Will return 0 if no string > min_string_match_len have been found */
+				      char *outbuf, u_int outbuf_len);
   char* ndpi_ssl_version2str(u_int16_t version);
 
   /* Serializer */
diff --git a/src/lib/ndpi_utils.c b/src/lib/ndpi_utils.c
index 02876d6f1..55c626c27 100644
--- a/src/lib/ndpi_utils.c
+++ b/src/lib/ndpi_utils.c
@@ -608,16 +608,21 @@ const char* ndpi_cipher2str(u_int32_t cipher) {
 
 static int ndpi_is_other_char(char c) {
   return((c == '.')
+	 || (c == ' ')
 	 || (c == '@')
+	 || (c == '/')
 	 );
 }
 
 /* ******************************************************************** */
 
 static int ndpi_is_valid_char(char c) {
-  return(isdigit(c)
-	 || isalpha(c)
-	 || ndpi_is_other_char(c));
+  if(ispunct(c) && (!ndpi_is_other_char(c)))
+    return(0);
+  else
+    return(isdigit(c)
+	   || isalpha(c)
+	   || ndpi_is_other_char(c));
 }
 
 /* ******************************************************************** */
@@ -628,11 +633,11 @@ static int ndpi_find_non_eng_bigrams(struct ndpi_detection_module_struct *ndpi_s
   char s[3];
 
   if((isdigit(str[0]) && isdigit(str[1]))
-     || (ndpi_is_other_char(str[0]) || ndpi_is_other_char(str[1]))
-     || (ndpi_is_other_char(str[0]) || ndpi_is_other_char(str[1]))
+     || ndpi_is_other_char(str[0])
+     || ndpi_is_other_char(str[1])
      )
     return(1);
-
+  
   s[0] = tolower(str[0]), s[1] = tolower(str[1]), s[2] = '\0';
 
   return(ndpi_match_bigram(ndpi_struct, &ndpi_struct->bigrams_automa, s));
@@ -643,13 +648,17 @@ static int ndpi_find_non_eng_bigrams(struct ndpi_detection_module_struct *ndpi_s
 /* #define PRINT_STRINGS 1 */
 
 int ndpi_has_human_readeable_string(struct ndpi_detection_module_struct *ndpi_struct,
-				    char *buffer, u_int buffer_size) {
-  u_int ret = 0, i = 0, do_cr = 0, len = 0;
-  const u_int8_t NDPI_MIN_VALID_STRING_LEN = 4; /* Will return 0 if no string > NDPI_MIN_VALID_STRING_LEN have been found */
+				    char *buffer, u_int buffer_size,
+				    u_int8_t min_string_match_len,
+				    char *outbuf, u_int outbuf_len) {
+  u_int ret = 0, i = 0, do_cr = 0, len = 0, o_idx = 0, being_o_idx = 0;
 
   if(buffer_size <= 0)
     return(0);
 
+  outbuf_len--;
+  outbuf[outbuf_len] = '\0';
+  
   for(i=0; i<buffer_size-2; i++) {
     if(ndpi_is_valid_char(buffer[i])
        && ndpi_is_valid_char(buffer[i+1])
@@ -657,23 +666,35 @@ int ndpi_has_human_readeable_string(struct ndpi_detection_module_struct *ndpi_st
 #ifdef PRINT_STRINGS
       printf("%c%c", buffer[i], buffer[i+1]);
 #endif
+      if(o_idx < outbuf_len) outbuf[o_idx++] = buffer[i];
+      if(o_idx < outbuf_len) outbuf[o_idx++] = buffer[i+1];
       do_cr = 1, i += 1, len += 2;
     } else {
       if(ndpi_is_valid_char(buffer[i]) && do_cr) {
 #ifdef PRINT_STRINGS
 	printf("%c", buffer[i]);
 #endif
+	if(o_idx < outbuf_len) outbuf[o_idx++] = buffer[i];
 	len += 1;
       }
 
       // printf("->> %c%c\n", isprint(buffer[i]) ? buffer[i] : '.', isprint(buffer[i+1]) ? buffer[i+1] : '.');
       if(do_cr) {
+	if(len > min_string_match_len)
+	  ret = 1;
+	else {
+	  o_idx = being_o_idx;
+	  being_o_idx = o_idx;
+	  outbuf[o_idx] = '\0';
+	}
+	
 #ifdef PRINT_STRINGS
-	printf(" [len: %u]\n", len);
+	printf(" [len: %u]%s\n", len, ret ? "<-- HIT" : "");
 #endif
-	if(len > NDPI_MIN_VALID_STRING_LEN)
-	  ret = 1;
 
+	if(ret)
+	  break;
+	
 	do_cr = 0, len = 0;
       }
     }