Re: [PR] libc/lib_getrandom.c: add random configuration check [nuttx]

[via GitHub]

yamt commented on code in PR #10925:
URL: https://github.com/apache/nuttx/pull/10925#discussion_r1366289017


##########
net/tcp/tcp_conn.c:
##########
@@ -579,27 +579,26 @@ int tcp_selectport(uint8_t domain,
                    uint16_t portno)
 {
   static uint16_t g_last_tcp_port;
-  ssize_t ret;
 
   /* Generate port base dynamically */
 
   if (g_last_tcp_port == 0)
     {
-      ret = getrandom(&g_last_tcp_port, sizeof(uint16_t), 0);
+#if defined(CONFIG_DEV_URANDOM) || defined(CONFIG_DEV_RANDOM)
+      ssize_t ret = getrandom(&g_last_tcp_port, sizeof(uint16_t), 0);
       if (ret < 0)
         {
           ret = getrandom(&g_last_tcp_port, sizeof(uint16_t), GRND_RANDOM);
         }
 
       if (ret != sizeof(uint16_t))
+#endif
         {
-          g_last_tcp_port = clock_systime_ticks() % 32000;
-        }
-      else
-        {
-          g_last_tcp_port = g_last_tcp_port % 32000;
+          g_last_tcp_port = (uint16_t)clock_systime_ticks();
         }
 
+      g_last_tcp_port = g_last_tcp_port % 32000;

Review Comment:
   > what's difference?
   
   plotted with https://github.com/yamt/garbage/blob/master/py/rand/plot.py
   
   
![hist](https://github.com/apache/nuttx/assets/1845377/c1a7fa8a-97d9-4e93-ba3f-4d2f241130e2)
   



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