fuzz: some improvements and add two new fuzzers (#1881)

Remove `FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION` define from
`fuzz/Makefile.am`; it is already included by the main configure script
(when fuzzing).

Add a knob to force disabling of AESNI optimizations: this way we can
fuzz also no-aesni crypto code.

Move CRC32 algorithm into the library.

Add some fake traces to extend fuzzing coverage. Note that these traces
are hand-made (via scapy/curl) and must not be used as "proof" that the
dissectors are really able to identify this kind of traffic.

Some small updates to some dissectors:

CSGO: remove a wrong rule (never triggered, BTW). Any UDP packet starting
with "VS01" will be classified as STEAM (see steam.c around line 111).
Googling it, it seems right so.

XBOX: XBOX only analyses UDP flows while HTTP only TCP ones; therefore
that condition is false.

RTP, STUN: removed useless "break"s

Zattoo: `flow->zattoo_stage` is never set to any values greater or equal
to 5, so these checks are never true.

PPStream: `flow->l4.udp.ppstream_stage` is never read. Delete it.

TeamSpeak: we check for `flow->packet_counter == 3` just above, so the
following check `flow->packet_counter >= 3` is always false.

4 files changed, 6 insertions, 4 deletions

diff --git a/src/include/ndpi_api.h b/src/include/ndpi_api.h
index 9968e9eb3..3abe2080d 100644
--- a/src/include/ndpi_api.h
+++ b/src/include/ndpi_api.h
@@ -1713,6 +1713,10 @@ extern "C" {
 
   /* ******************************* */
 
+  u_int32_t ndpi_crc32(const void* data, size_t n_bytes);
+
+  /* ******************************* */
+
   int ndpi_des_init(struct ndpi_des_struct *des, double alpha, double beta, float significance);
   int ndpi_des_add_value(struct ndpi_des_struct *des, const double _value, double *forecast, double *confidence_band);
   void ndpi_des_fitting(double *values, u_int32_t num_values, float *ret_alpha, float *ret_beta);
diff --git a/src/include/ndpi_main.h b/src/include/ndpi_main.h
index 6662c0ca9..1337cc63f 100644
--- a/src/include/ndpi_main.h
+++ b/src/include/ndpi_main.h
@@ -125,6 +125,8 @@ extern "C" {
 
   extern u_int8_t ndpi_is_proto(ndpi_protocol proto, u_int16_t p);
 
+  extern void ndpi_search_tcp_or_udp(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow);
+
 #ifdef NDPI_ENABLE_DEBUG_MESSAGES
   void ndpi_debug_get_last_log_function_line(struct ndpi_detection_module_struct *ndpi_struct,
 					     const char **file, const char **func, u_int32_t * line);
diff --git a/src/include/ndpi_protocols.h b/src/include/ndpi_protocols.h
index 9b98c82d1..0389bcfad 100644
--- a/src/include/ndpi_protocols.h
+++ b/src/include/ndpi_protocols.h
@@ -49,7 +49,6 @@ u_int ndpi_search_tcp_or_udp_raw(struct ndpi_detection_module_struct *ndpi_struc
 				 u_int32_t saddr, u_int32_t daddr,
 				 u_int16_t sport, u_int16_t dport);
 
-void ndpi_search_tcp_or_udp(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow);
 
 void init_diameter_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id);
 void init_afp_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id);
diff --git a/src/include/ndpi_typedefs.h b/src/include/ndpi_typedefs.h
index 9460b2888..bd811f6a2 100644
--- a/src/include/ndpi_typedefs.h
+++ b/src/include/ndpi_typedefs.h
@@ -769,9 +769,6 @@ struct ndpi_flow_tcp_struct {
 /* ************************************************** */
 
 struct ndpi_flow_udp_struct {
-  /* NDPI_PROTOCOL_PPSTREAM */
-  u_int32_t ppstream_stage:3;		  // 0 - 7
-
   /* NDPI_PROTOCOL_HALFLIFE2 */
   u_int32_t halflife2_stage:2;		  // 0 - 2