From 91bb77a8806ee2987e856f66674cf3aa8b1d60db Mon Sep 17 00:00:00 2001
From: Ivan Nardi <12729895+IvanNardi@users.noreply.github.com>
Date: Wed, 22 Dec 2021 19:54:06 +0100
Subject: A final(?) effort to reduce memory usage per flow (#1389)

Remove some unused fields and re-organize other ones.
In particular:
* Update the parameters of `ndpi_ssl_version2str()` function
* Zattoo, Thunder: these timestamps aren't really used.
* Ftp/mail: these protocols are dissected only over TCP.
* Attention must be paid to TLS.Bittorrent flows to avoid invalid
read/write to `flow->protos.bittorrent.hash` field.

This is the last(?) commit of a long series (see 22241a1d, 227e586e,
730c2360, a8ffcd8b) aiming to reduce library memory consumption.

Before, at nDPI 4.0 (more precisly, at a6b10cf7, because memory stats
were wrong until that commit):
```
nDPI Memory statistics:
	nDPI Memory (once):      221.15 KB
	Flow Memory (per flow):  2.94 KB
```
Now:
```
nDPI Memory statistics:
	nDPI Memory (once):      231.71 KB
	Flow Memory (per flow):  1008 B       <---------
```
i.e. memory usage per flow has been reduced by 66%, dropping below the
psychological threshold of 1 KB.

To further reduce this value, we probably need to look into #1279:
let's fight this battle another day.
---
 src/lib/protocols/tls.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

(limited to 'src/lib/protocols/tls.c')

diff --git a/src/lib/protocols/tls.c b/src/lib/protocols/tls.c
index 87553de87..b8f8159e5 100644
--- a/src/lib/protocols/tls.c
+++ b/src/lib/protocols/tls.c
@@ -2030,6 +2030,7 @@ int processClientServerHello(struct ndpi_detection_module_struct *ndpi_struct,
 		u_int16_t s_offset = offset+extension_offset;
 		u_int8_t version_len = packet->payload[s_offset];
 		char version_str[256];
+		char buf_ver_tmp[16];
 		size_t version_str_len = 0;
 		version_str[0] = 0;
 #ifdef DEBUG_TLS
@@ -2049,14 +2050,14 @@ int processClientServerHello(struct ndpi_detection_module_struct *ndpi_struct,
 
 #ifdef DEBUG_TLS
 		    printf("Client TLS [TLS version: %s/0x%04X]\n",
-			   ndpi_ssl_version2str(flow, tls_version, &unknown_tls_version), tls_version);
+			   ndpi_ssl_version2str(buf_ver_tmp, sizeof(buf_ver_tmp), tls_version, &unknown_tls_version), tls_version);
 #endif
 
 		    if((version_str_len+8) < sizeof(version_str)) {
 		      int rc = snprintf(&version_str[version_str_len],
 					sizeof(version_str) - version_str_len, "%s%s",
 					(version_str_len > 0) ? "," : "",
-					ndpi_ssl_version2str(flow, tls_version, &unknown_tls_version));
+					ndpi_ssl_version2str(buf_ver_tmp, sizeof(buf_ver_tmp), tls_version, &unknown_tls_version));
 		      if(rc <= 0)
 			break;
 		      else
-- 
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