Added a config option to randomize initial local TCP/UDP ports (so that different port ranges are used after a reboot; bug #33818; this one added tcp_init/udp_init functions again);

fixed a possible endless loop in tcp_new_port() if the number of active PCBs exceeds the number of available ports;

src/include/lwip/opt.h

@@ -606,6 +606,15 @@
 #define IP_FORWARD_ALLOW_TX_ON_RX_NETIF 0
 #endif
 
+/**
+ * LWIP_RANDOMIZE_INITIAL_LOCAL_PORTS==1: randomize the local port for the first
+ * local TCP/UDP pcb (default==0). This can prevent creating predictable port
+ * numbers after booting a device.
+ */
+#ifndef LWIP_RANDOMIZE_INITIAL_LOCAL_PORTS
+#define LWIP_RANDOMIZE_INITIAL_LOCAL_PORTS 0
+#endif
+
 /*
    ----------------------------------
    ---------- ICMP options ----------

src/include/lwip/tcp_impl.h

@@ -52,7 +52,7 @@ extern "C" {
 /* Functions for interfacing with TCP: */
 
 /* Lower layer interface to TCP: */
-#define tcp_init() /* Compatibility define, no init needed. */
+void             tcp_init    (void);  /* Initialize this module. */
 void             tcp_tmr     (void);  /* Must be called every
                                          TCP_TMR_INTERVAL
                                          ms. (Typically 250 ms). */

src/include/lwip/udp.h

@@ -178,7 +178,7 @@ err_t            udp_send_chksum(struct udp_pcb *pcb, struct pbuf *p,
 /* The following functions are the lower layer interface to UDP. */
 void             udp_input      (struct pbuf *p, struct netif *inp);
 
-#define udp_init() /* Compatibility define, not init needed. */
+void             udp_init       (void);
 
 #if LWIP_IPV6
 struct udp_pcb * udp_new_ip6(void);