patch #6865 (SO_REUSEADDR for TCP): if tcp_pcb.flags has TF_REUSEADDR set, allow binding to endpoint in TIME_WAIT

CHANGELOG

@@ -19,6 +19,10 @@ HISTORY
 
   ++ New features:
 
+  2010-02-12: Simon Goldschmidt/Jeff Barber
+  * tcp.c/h: patch #6865 (SO_REUSEADDR for TCP): if tcp_pcb.flags has
+    TF_REUSEADDR set, allow binding to endpoint in TIME_WAIT
+
   2010-02-12: Simon Goldschmidt
   * sys layer: task #10139 (Prefer statically allocated memory): converted
     mbox and semaphore functions to take pointers to sys_mbox_t/sys_sem_t;

src/core/tcp.c

@@ -317,12 +317,16 @@ tcp_bind(struct tcp_pcb *pcb, ip_addr_t *ipaddr, u16_t port)
       }
     }
   }
-  /* @todo: until SO_REUSEADDR is implemented (see task #6995 on savannah),
+  /* Unless the REUSEADDR flag is set,
    * we have to check the pcbs in TIME-WAIT state, also: */
-  for(cpcb = tcp_tw_pcbs; cpcb != NULL; cpcb = cpcb->next) {
-    if (cpcb->local_port == port) {
-      if (ip_addr_cmp(&(cpcb->local_ip), ipaddr)) {
-        return ERR_USE;
+  if ((pcb->flags & TF_REUSEADDR) == 0) {
+    for(cpcb = tcp_tw_pcbs; cpcb != NULL; cpcb = cpcb->next) {
+      if (cpcb->local_port == port) {
+        if (ip_addr_isany(&(cpcb->local_ip)) ||
+            ip_addr_isany(ipaddr) ||
+            ip_addr_cmp(&(cpcb->local_ip), ipaddr)) {
+          return ERR_USE;
+        }
       }
     }
   }

src/include/lwip/tcp.h

@@ -370,6 +370,7 @@ struct tcp_pcb {
 #define TF_ACK_NOW     ((u8_t)0x02U)   /* Immediate ACK. */
 #define TF_INFR        ((u8_t)0x04U)   /* In fast recovery. */
 #define TF_TIMESTAMP   ((u8_t)0x08U)   /* Timestamp option enabled */
+#define TF_REUSEADDR   ((u8_t)0x10U)   /* Bind to endpoint in TIME_WAIT */
 #define TF_FIN         ((u8_t)0x20U)   /* Connection was closed locally (FIN segment enqueued). */
 #define TF_NODELAY     ((u8_t)0x40U)   /* Disable Nagle algorithm */
 #define TF_NAGLEMEMERR ((u8_t)0x80U)   /* nagle enabled, memerr, try to output to prevent delayed ACK to happen */