From: Angus Gratton <angus@espressif.com>
Date: Thu, 20 Jul 2017 00:04:20 +0000 (+1000)
Subject: lwip: Use hardware RNG for LWIP_RAND(), use LWIP_RAND() for random port assignment
X-Git-Tag: v3.1-dev~302^2~1
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=73b3ae8a2d9e51cdcec825ec94b321ef04a20a2b;p=esp-idf

lwip: Use hardware RNG for LWIP_RAND(), use LWIP_RAND() for random port assignment
---

diff --git a/components/lwip/core/tcp.c b/components/lwip/core/tcp.c
index 3ad5903d9e..1f915128a4 100755
--- a/components/lwip/core/tcp.c
+++ b/components/lwip/core/tcp.c
@@ -696,14 +696,12 @@ tcp_new_port(void)
 again:
 
 #if ESP_RANDOM_TCP_PORT
-	tcp_port = system_get_time();
-	if (tcp_port < 0)
-		tcp_port = LWIP_RAND() - tcp_port;
-	tcp_port %= TCP_LOCAL_PORT_RANGE_START;
+  tcp_port = abs(LWIP_RAND()) % (TCP_LOCAL_PORT_RANGE_END - TCP_LOCAL_PORT_RANGE_START);
+  tcp_port += TCP_LOCAL_PORT_RANGE_START;
 #else
-      if (tcp_port++ == TCP_LOCAL_PORT_RANGE_END) {
-            tcp_port = TCP_LOCAL_PORT_RANGE_START;
-      }
+  if (tcp_port++ == TCP_LOCAL_PORT_RANGE_END) {
+    tcp_port = TCP_LOCAL_PORT_RANGE_START;
+  }
 #endif
 
   /* Check all PCB lists. */
diff --git a/components/lwip/include/lwip/port/arch/sys_arch.h b/components/lwip/include/lwip/port/arch/sys_arch.h
index 8d30ef171d..716fd9fa53 100644
--- a/components/lwip/include/lwip/port/arch/sys_arch.h
+++ b/components/lwip/include/lwip/port/arch/sys_arch.h
@@ -67,7 +67,6 @@ typedef struct sys_mbox_s {
 #define sys_sem_valid( x ) ( ( ( *x ) == NULL) ? pdFALSE : pdTRUE )
 #define sys_sem_set_invalid( x ) ( ( *x ) = NULL )
 
-uint32_t system_get_time(void);
 void sys_delay_ms(uint32_t ms);
 sys_sem_t* sys_thread_sem_init(void);
 void sys_thread_sem_deinit(void);
diff --git a/components/lwip/include/lwip/port/lwipopts.h b/components/lwip/include/lwip/port/lwipopts.h
index 49c2174bf3..7bc4021e5a 100644
--- a/components/lwip/include/lwip/port/lwipopts.h
+++ b/components/lwip/include/lwip/port/lwipopts.h
@@ -37,6 +37,7 @@
 #include <sys/time.h>
 #include <sys/fcntl.h>
 #include "esp_task.h"
+#include "esp_system.h"
 #include "sdkconfig.h"
 
 /* Enable all Espressif-only options */
@@ -65,7 +66,7 @@
  */
 #define SMEMCPY(dst,src,len)            memcpy(dst,src,len)
 
-#define LWIP_RAND       rand
+#define LWIP_RAND       esp_random
 
 /*
    ------------------------------------