From 95e85c74e7310a595aa6bd57dbbc69ec3516e9c6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marcel=20St=C3=B6r?= <marcelstoer@users.noreply.github.com>
Date: Sat, 20 Aug 2016 22:06:40 +0200
Subject: [PATCH] =?UTF-8?q?Revert=20"with=20this=20small=20fix,=20the=20DN?=
 =?UTF-8?q?S=20engine=20is=20RFC=205452=20compliant=20because=20it=20?=
 =?UTF-8?q?=E2=80=A6"=20(#1465)?=
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---
 app/include/lwip/udp.h |  5 -----
 app/lwip/core/dns.c    | 10 ++--------
 app/lwip/core/udp.c    |  4 ++++
 3 files changed, 6 insertions(+), 13 deletions(-)

diff --git a/app/include/lwip/udp.h b/app/include/lwip/udp.h
index 760b24cf..cb53d33e 100644
--- a/app/include/lwip/udp.h
+++ b/app/include/lwip/udp.h
@@ -156,11 +156,6 @@ void             udp_input      (struct pbuf *p, struct netif *inp)ICACHE_FLASH_
 
 #define udp_init() /* Compatibility define, not init needed. */
 
-#ifndef UDP_LOCAL_PORT_RANGE_START
-#define UDP_LOCAL_PORT_RANGE_START 4096
-#define UDP_LOCAL_PORT_RANGE_END   0x7fff
-#endif
-
 #if UDP_DEBUG
 void udp_debug_print(struct udp_hdr *udphdr)ICACHE_FLASH_ATTR;
 #else
diff --git a/app/lwip/core/dns.c b/app/lwip/core/dns.c
index 72a31995..c0d616f2 100644
--- a/app/lwip/core/dns.c
+++ b/app/lwip/core/dns.c
@@ -254,14 +254,8 @@ dns_init()
       LWIP_ASSERT("For implicit initialization to work, DNS_STATE_UNUSED needs to be 0",
         DNS_STATE_UNUSED == 0);
 
-      /* initialize DNS client, try to get RFC 5452 random source port */
-      u16_t port = UDP_LOCAL_PORT_RANGE_START + (os_random() % (UDP_LOCAL_PORT_RANGE_END - UDP_LOCAL_PORT_RANGE_START));
-      for(;;) {
-        if(udp_bind(dns_pcb, IP_ADDR_ANY, port) == ERR_OK)
-          break;
-        LWIP_ASSERT("Unable to get a PCB for DNS", port != 0);
-        port=0; // try again with random source
-      }
+      /* initialize DNS client */
+      udp_bind(dns_pcb, IP_ADDR_ANY, 0);
       udp_recv(dns_pcb, dns_recv, NULL);
 
       /* initialize default DNS primary server */
diff --git a/app/lwip/core/udp.c b/app/lwip/core/udp.c
index 2d794818..e44d7f38 100644
--- a/app/lwip/core/udp.c
+++ b/app/lwip/core/udp.c
@@ -758,6 +758,10 @@ udp_bind(struct udp_pcb *pcb, ip_addr_t *ipaddr, u16_t port)
 
   /* no port specified? */
   if (port == 0) {
+#ifndef UDP_LOCAL_PORT_RANGE_START
+#define UDP_LOCAL_PORT_RANGE_START 4096
+#define UDP_LOCAL_PORT_RANGE_END   0x7fff
+#endif
     port = UDP_LOCAL_PORT_RANGE_START;
     ipcb = udp_pcbs;
     while ((ipcb != NULL) && (port != UDP_LOCAL_PORT_RANGE_END)) {